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ToastyFS/TinyDFS.c
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cozis 1f4a9956da First commit
2025-10-27 18:01:33 +01:00

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// Architecture
// A TinyDFS instance is composed by a metadata server, a number
// of chunk servers, and a number of clients.
//
// The metadata server stores the full file system hieararchy,
// except instead of storing the file contents, it stores an
// array of hashes of the chunks of each file. A "chunk" is a
// file range that is fixed for a single file but may vary
// between files. Chunk servers hold an array of chunks that
// are identified by their hash. The metadata server keeps
// track of which chunks each chunk server is holding.
//
// Clients are users of the file system that can read and
// write metadata and files. They are assumed to behave
// correctly.
//
// Any read and write operation that doesn't involve file
// contents can be performed by clients by talking to the
// metadata server directly. Such operations include creating
// an empty file or a directory, deleting a file or directory,
// listing files.
//
// If a client wants to read a range of bytes from a file,
// it sends the metadata server the file name and range.
// The metadata server responds with the chunk size of that
// file, the list of hashes for the chunks involved in the
// read, and the IP addresses of the chunk servers that hold
// each chunk. The metadata server also adds the IP addresses
// of three chunk servers any new chunks should be written
// to. The client can then download the chunks from the chunk
// servers and reassemble the result.
//
// If a client wants to write at a range of bytes of a file,
// it starts by reading that range from the metadata server,
// getting the list of hashes it will modify, their locations,
// and locations for any new chunks. The client then modifies
// the chunk by sending to each chunk server the hash to modify
// and the patch (a range of bytes within a chunk plus the new
// data). The chunk server creates a new modified chunk and
// keeps the old version, then returns the new hash. If all
// modifications are successful, the client holds the set of
// old hashes and new hashes for that file range. It completes
// the write by telling the metadata server to swap the old
// hashes with the new ones. If the old hashes don't match,
// another write succeded in the mean time and touched that
// range, therefore the write fails. If the old hashes match,
// the write succeded. If the client fails to modify any
// chunks, it doesn't commit the write with the metadata server.
// Note that write failures may cause chunks to be orphaned
// on chunk servers. This is solved by a garbage collection
// algorithm implemented by the synchronization messages
// between metadata and chunk server.
//
// Note that clients may cache chunks and index them by their
// hash. When they read a file and receive its hashes, they may
// avoid reaching for the chunk servers if they already cached
// the chunks with those hashes. This allows reading files with
// only one round trip at no cost of correctness. If getting
// the up-to-date contents is not a concern, clients may also
// cache file metadata.
//
// Metadata and chunk server exchange:
//
// The metadata server is only aware of each chunk server
// as long as they have a TCP connection. When a chunk server
// first connects to the metadata server, it authenticates
// itself and sends its own IP addresses. If the server is
// authentic, the metadata server requests the full list
// of chunks the chunk server is holding. Upon receiving the
// state of chunk server, the metadata server adds all useful
// chunks to the "old_list" and all useless chunks to the
// "rem_list", then sends the rem_list to the chunk server
// which removes those chunks.
//
// When writes are committed to the metadata server involving
// new chunks to a chunk server, the metadata server adds those
// hashes to an "add_list" and any hashes that are not useful
// anymore to the rem_list.
//
// Periodically, the metadata server sends the add_list and
// rem_list to the chunk server. These list tell the chunk
// server the ideal state it should have from the point of
// view of the metadata server. Elements in the add_list should
// already be in the chunk servers, and elements from the
// rem_list are to be removed. A chunk server marks any chunk
// in the rem_list as to be removed and checks that hashes
// in the add list are present. If a chunk in the add list
// is marked as to be removed, it is unmarked. When a chunk
// is marked as to be removed for a certain amount of time,
// it is permanently deleted. When the synchronization is
// complete, the metadata server merges the add_list into
// the old_list and clears the rem_list. If chunks in the
// add_list are not present in the chunk server, it responds
// with an error message containing the list of missing chunks.
// The metadata server then responds with a list of chunk
// server addresses where the chunk server with the missing
// chunk can download it from. Each chunk server goes
// through its download list one at the time downloading
// the missing chunks.
//
// Note that if the chunk server finds that its holding some
// chunks that are not in the hash list of the metadata server,
// that does not mean they are orphaned. It's possible that
// some writes are being performed by clients that have uploaded
// chunks to that chunk server but didn't yet acknowledge it
// to the metadata server. If all goes well and the write
// succeded, the metadata server will add those hashes to the
// hash list. Chunk servers should only drop chunks if they
// are not referenced by the metadata server for a period of
// time (say, 30 minutes).
//
// Security
// All nodes of the system share a secret key and use it to
// authenticate each other and encrypt messages. This allows
// the server to accept new chunk servers and clients with
// no prior setup
//
// Reliability
// The metadata server is a single point of failure. To reduce
// the impact of crashes, the metadata server stores all write
// operations into a write-ahead log that is replayed any time
// the process goes online.
//
// TODO: When a write occurs, the written to chunks must be marked
// as orphaned or "to-be-deleted" unless they are used by
// someone else
#include <stdio.h>
#include <assert.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <stdbool.h>
#ifdef _WIN32
#include <winsock2.h>
#include <ws2tcpip.h>
#define POLL WSAPoll
#define CLOSE_SOCKET closesocket
#else
#include <time.h>
#include <poll.h>
#include <errno.h>
#include <dirent.h>
#include <unistd.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#define SOCKET int
#define INVALID_SOCKET -1
#define POLL poll
#define CLOSE_SOCKET close
#endif
#if !defined(BUILD_METADATA_SERVER) && !defined(BUILD_CHUNK_SERVER)
#define BUILD_METADATA_SERVER
#endif
//////////////////////////////////////////////////////////////////////////
// BASICS
//////////////////////////////////////////////////////////////////////////
typedef struct {
char data[64];
} SHA256;
typedef struct {
char *ptr;
int len;
} string;
typedef uint64_t Time;
#define INVALID_TIME ((Time) -1)
#define S(X) ((string) { (X), (int) sizeof(X)-1 })
#define MIN(X, Y) ((X) < (Y) ? (X) : (Y))
#define UNREACHABLE __builtin_trap();
static bool streq(string s1, string s2)
{
if (s1.len != s2.len)
return false;
for (int i = 0; i < s1.len; i++)
if (s1.ptr[i] != s2.ptr[i])
return false;
return true;
}
// Returns the current time in milliseconds since
// an unspecified time in the past (useful to calculate
// elapsed time intervals)
static Time get_current_time(void)
{
#ifdef _WIN32
{
int64_t count;
int64_t freq;
int ok;
ok = QueryPerformanceCounter((LARGE_INTEGER*) &count);
if (!ok) return INVALID_TIME;
ok = QueryPerformanceFrequency((LARGE_INTEGER*) &freq);
if (!ok) return INVALID_TIME;
uint64_t res = 1000 * (double) count / freq;
return res;
}
#else
{
struct timespec time;
if (clock_gettime(CLOCK_REALTIME, &time))
return INVALID_TIME;
uint64_t res;
uint64_t sec = time.tv_sec;
if (sec > UINT64_MAX / 1000000000)
return INVALID_TIME;
res = sec * 1000;
uint64_t nsec = time.tv_nsec;
if (res > UINT64_MAX - nsec)
return INVALID_TIME;
res += nsec / 1000000;
return res;
}
#endif
}
//////////////////////////////////////////////////////////////////////////
// SHA256
//////////////////////////////////////////////////////////////////////////
//usr/bin/env clang -Ofast -Wall -Wextra -pedantic ${0} -o ${0%%.c*} $* ;exit $?
//
// SHA-256 implementation, Mark 2
//
// Copyright (c) 2010,2014 Literatecode, http://www.literatecode.com
// Copyright (c) 2022 Ilia Levin (ilia@levin.sg)
//
// Permission to use, copy, modify, and distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
//
#define SHA256_SIZE_BYTES (32)
typedef struct {
uint8_t buf[64];
uint32_t hash[8];
uint32_t bits[2];
uint32_t len;
uint32_t rfu__;
uint32_t W[64];
} sha256_context;
#ifndef _cbmc_
#define __CPROVER_assume(...) do {} while(0)
#endif
#define FN_ static inline __attribute__((const))
static const uint32_t K[64] = {
0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
};
FN_ uint8_t _shb(uint32_t x, uint32_t n)
{
return ((x >> (n & 31)) & 0xff);
}
FN_ uint32_t _shw(uint32_t x, uint32_t n)
{
return ((x << (n & 31)) & 0xffffffff);
}
FN_ uint32_t _r(uint32_t x, uint8_t n)
{
return ((x >> n) | _shw(x, 32 - n));
}
FN_ uint32_t _Ch(uint32_t x, uint32_t y, uint32_t z)
{
return ((x & y) ^ ((~x) & z));
}
FN_ uint32_t _Ma(uint32_t x, uint32_t y, uint32_t z)
{
return ((x & y) ^ (x & z) ^ (y & z));
}
FN_ uint32_t _S0(uint32_t x)
{
return (_r(x, 2) ^ _r(x, 13) ^ _r(x, 22));
}
FN_ uint32_t _S1(uint32_t x)
{
return (_r(x, 6) ^ _r(x, 11) ^ _r(x, 25));
}
FN_ uint32_t _G0(uint32_t x)
{
return (_r(x, 7) ^ _r(x, 18) ^ (x >> 3));
}
FN_ uint32_t _G1(uint32_t x)
{
return (_r(x, 17) ^ _r(x, 19) ^ (x >> 10));
}
FN_ uint32_t _word(uint8_t *c)
{
return (_shw(c[0], 24) | _shw(c[1], 16) | _shw(c[2], 8) | (c[3]));
}
static void _addbits(sha256_context *ctx, uint32_t n)
{
__CPROVER_assume(__CPROVER_DYNAMIC_OBJECT(ctx));
if (ctx->bits[0] > (0xffffffff - n)) {
ctx->bits[1] = (ctx->bits[1] + 1) & 0xFFFFFFFF;
}
ctx->bits[0] = (ctx->bits[0] + n) & 0xFFFFFFFF;
} // _addbits
static void _hash(sha256_context *ctx)
{
__CPROVER_assume(__CPROVER_DYNAMIC_OBJECT(ctx));
register uint32_t a, b, c, d, e, f, g, h;
uint32_t t[2];
a = ctx->hash[0];
b = ctx->hash[1];
c = ctx->hash[2];
d = ctx->hash[3];
e = ctx->hash[4];
f = ctx->hash[5];
g = ctx->hash[6];
h = ctx->hash[7];
for (uint32_t i = 0; i < 64; i++) {
if (i < 16) {
ctx->W[i] = _word(&ctx->buf[_shw(i, 2)]);
} else {
ctx->W[i] = _G1(ctx->W[i - 2]) + ctx->W[i - 7] +
_G0(ctx->W[i - 15]) + ctx->W[i - 16];
}
t[0] = h + _S1(e) + _Ch(e, f, g) + K[i] + ctx->W[i];
t[1] = _S0(a) + _Ma(a, b, c);
h = g;
g = f;
f = e;
e = d + t[0];
d = c;
c = b;
b = a;
a = t[0] + t[1];
}
ctx->hash[0] += a;
ctx->hash[1] += b;
ctx->hash[2] += c;
ctx->hash[3] += d;
ctx->hash[4] += e;
ctx->hash[5] += f;
ctx->hash[6] += g;
ctx->hash[7] += h;
}
static void sha256_init(sha256_context *ctx)
{
if (ctx != NULL) {
ctx->bits[0] = ctx->bits[1] = ctx->len = 0;
ctx->hash[0] = 0x6a09e667;
ctx->hash[1] = 0xbb67ae85;
ctx->hash[2] = 0x3c6ef372;
ctx->hash[3] = 0xa54ff53a;
ctx->hash[4] = 0x510e527f;
ctx->hash[5] = 0x9b05688c;
ctx->hash[6] = 0x1f83d9ab;
ctx->hash[7] = 0x5be0cd19;
}
}
static void sha256_hash(sha256_context *ctx, const void *data, size_t len)
{
const uint8_t *bytes = (const uint8_t *)data;
if ((ctx != NULL) && (bytes != NULL) && (ctx->len < sizeof(ctx->buf))) {
__CPROVER_assume(__CPROVER_DYNAMIC_OBJECT(bytes));
__CPROVER_assume(__CPROVER_DYNAMIC_OBJECT(ctx));
for (size_t i = 0; i < len; i++) {
ctx->buf[ctx->len++] = bytes[i];
if (ctx->len == sizeof(ctx->buf)) {
_hash(ctx);
_addbits(ctx, sizeof(ctx->buf) * 8);
ctx->len = 0;
}
}
}
}
static void sha256_done(sha256_context *ctx, uint8_t *hash)
{
register uint32_t i, j;
if (ctx != NULL) {
j = ctx->len % sizeof(ctx->buf);
ctx->buf[j] = 0x80;
for (i = j + 1; i < sizeof(ctx->buf); i++) {
ctx->buf[i] = 0x00;
}
if (ctx->len > 55) {
_hash(ctx);
for (j = 0; j < sizeof(ctx->buf); j++) {
ctx->buf[j] = 0x00;
}
}
_addbits(ctx, ctx->len * 8);
ctx->buf[63] = _shb(ctx->bits[0], 0);
ctx->buf[62] = _shb(ctx->bits[0], 8);
ctx->buf[61] = _shb(ctx->bits[0], 16);
ctx->buf[60] = _shb(ctx->bits[0], 24);
ctx->buf[59] = _shb(ctx->bits[1], 0);
ctx->buf[58] = _shb(ctx->bits[1], 8);
ctx->buf[57] = _shb(ctx->bits[1], 16);
ctx->buf[56] = _shb(ctx->bits[1], 24);
_hash(ctx);
if (hash != NULL) {
for (i = 0, j = 24; i < 4; i++, j -= 8) {
hash[i + 0] = _shb(ctx->hash[0], j);
hash[i + 4] = _shb(ctx->hash[1], j);
hash[i + 8] = _shb(ctx->hash[2], j);
hash[i + 12] = _shb(ctx->hash[3], j);
hash[i + 16] = _shb(ctx->hash[4], j);
hash[i + 20] = _shb(ctx->hash[5], j);
hash[i + 24] = _shb(ctx->hash[6], j);
hash[i + 28] = _shb(ctx->hash[7], j);
}
}
}
}
static void sha256(const void *data, size_t len, uint8_t *hash)
{
sha256_context ctx;
sha256_init(&ctx);
sha256_hash(&ctx, data, len);
sha256_done(&ctx, hash);
}
//////////////////////////////////////////////////////////////////////////
// FILE SYSTEM
//////////////////////////////////////////////////////////////////////////
#ifdef __linux__
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <sys/file.h>
#include <sys/stat.h>
#endif
#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#endif
typedef struct {
uint64_t data;
} Handle;
static int rename_file_or_dir(string oldpath, string newpath);
static int file_open(string path, Handle *fd)
{
#ifdef __linux__
char zt[1<<10];
if (path.len >= (int) sizeof(zt))
return -1;
memcpy(zt, path.ptr, path.len);
zt[path.len] = '\0';
int ret = open(zt, O_RDWR | O_CREAT | O_APPEND, 0644);
if (ret < 0)
return -1;
*fd = (Handle) { (uint64_t) ret };
return 0;
#endif
#ifdef _WIN32
WCHAR wpath[MAX_PATH];
MultiByteToWideChar(CP_UTF8, 0, path.ptr, path.len, wpath, MAX_PATH);
wpath[path.len] = L'\0';
HANDLE h = CreateFileW(
wpath,
GENERIC_WRITE | GENERIC_READ,
0,
NULL,
OPEN_ALWAYS,
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_WRITE_THROUGH,
NULL
);
if (h == INVALID_HANDLE_VALUE)
return -1;
*fd = (Handle) { (uint64_t) h };
return 0;
#endif
}
static void file_close(Handle fd)
{
#ifdef __linux__
close((int) fd.data);
#endif
#ifdef _WIN32
CloseHandle((HANDLE) fd.data);
#endif
}
static int file_lock(Handle fd)
{
#ifdef __linux__
if (flock((int) fd.data, LOCK_EX) < 0)
return -1;
return 0;
#endif
#ifdef _WIN32
if (!LockFile((HANDLE) fd.data, 0, 0, MAXDWORD, MAXDWORD))
return -1;
return 0;
#endif
}
static int file_unlock(Handle fd)
{
#ifdef __linux__
if (flock((int) fd.data, LOCK_UN) < 0)
return -1;
return 0;
#endif
#ifdef _WIN32
if (!UnlockFile((HANDLE) fd.data, 0, 0, MAXDWORD, MAXDWORD))
return -1;
return 0;
#endif
}
static int file_sync(Handle fd)
{
#ifdef __linux__
if (fsync((int) fd.data) < 0)
return -1;
return 0;
#endif
#ifdef _WIN32
if (!FlushFileBuffers((HANDLE) fd.data))
return -1;
return 0;
#endif
}
static int file_read(Handle fd, char *dst, int max)
{
#ifdef __linux__
return read((int) fd.data, dst, max);
#endif
#ifdef _WIN32
DWORD num;
if (!ReadFile((HANDLE) fd.data, dst, max, &num, NULL))
return -1;
if (num > INT_MAX)
return -1;
return num;
#endif
}
static int file_write(Handle fd, char *src, int len)
{
#ifdef __linux__
return write((int) fd.data, src, len);
#endif
#ifdef _WIN32
DWORD num;
if (!WriteFile((HANDLE) fd.data, src, len, &num, NULL))
return -1;
if (num > INT_MAX)
return -1;
return num;
#endif
}
static int file_size(Handle fd, size_t *len)
{
#ifdef __linux__
struct stat buf;
if (fstat((int) fd.data, &buf) < 0)
return -1;
if (buf.st_size < 0 || (uint64_t) buf.st_size > SIZE_MAX)
return -1;
*len = (size_t) buf.st_size;
return 0;
#endif
#ifdef _WIN32
LARGE_INTEGER buf;
if (!GetFileSizeEx((HANDLE) fd.data, &buf))
return -1;
if (buf.QuadPart < 0 || (uint64_t) buf.QuadPart > SIZE_MAX)
return -1;
*len = buf.QuadPart;
return 0;
#endif
}
// TODO: test this
static string parent_path(string path)
{
if (path.len > 0 && path.ptr[path.len-1] == '/')
path.len--;
if (path.len == 0)
return S("");
while (path.len > 0 && path.ptr[path.len-1] != '/')
path.len--;
if (path.len > 0)
path.len--;
return path;
}
static int write_bytes(int fd, string data)
{
size_t written = 0;
while (written < (size_t) data.len) {
int ret = write(fd, data.ptr + written, data.len - written);
if (ret < 0) {
if (errno == EINTR)
continue;
return -1;
}
written += (size_t) ret;
}
assert((size_t) data.len == written);
return 0;
}
static int file_write_atomic(string path, string content)
{
string parent = parent_path(path);
char pattern[] = "/tmp_XXXXXXXX";
char tmp_path[PATH_MAX];
if (parent.len + strlen(pattern) >= (int) sizeof(tmp_path))
return -1;
memcpy(tmp_path, parent.ptr, parent.len);
memcpy(tmp_path + parent.len, pattern, strlen(pattern));
tmp_path[parent.len + strlen(pattern)] = '\0';
int fd = mkstemp(tmp_path);
if (fd < 0)
return -1;
if (write_bytes(fd, content) < 0) {
close(fd);
remove(tmp_path);
return -1;
}
#ifdef _WIN32
if (_commit(fd)) {
close(fd);
remove(tmp_path);
return -1;
}
#else
if (fsync(fd)) {
close(fd);
remove(tmp_path);
return -1;
}
#endif
close(fd);
if (rename_file_or_dir((string) { tmp_path, strlen(tmp_path) }, path)) {
remove(tmp_path);
return -1;
}
return 0;
}
static int create_dir(string path)
{
char zt[PATH_MAX];
if (path.len >= (int) sizeof(zt))
return -1;
memcpy(zt, path.ptr, path.len);
zt[path.len] = '\0';
#ifdef _WIN32
if (mkdir(zt) < 0)
return -1;
#else
if (mkdir(zt, 0766))
return -1;
#endif
return 0;
}
static int rename_file_or_dir(string oldpath, string newpath)
{
char oldpath_zt[PATH_MAX];
if (oldpath.len >= (int) sizeof(oldpath_zt))
return -1;
memcpy(oldpath_zt, oldpath.ptr, oldpath.len);
oldpath_zt[oldpath.len] = '\0';
char newpath_zt[PATH_MAX];
if (newpath.len >= (int) sizeof(newpath_zt))
return -1;
memcpy(newpath_zt, newpath.ptr, newpath.len);
newpath_zt[newpath.len] = '\0';
if (rename(oldpath_zt, newpath_zt))
return -1;
return 0;
}
static int remove_file_or_dir(string path)
{
char path_zt[PATH_MAX];
if (path.len >= (int) sizeof(path_zt))
return -1;
memcpy(path_zt, path.ptr, path.len);
path_zt[path.len] = '\0';
if (remove(path_zt))
return -1;
return 0;
}
static int get_full_path(string path, char *dst)
{
char path_zt[PATH_MAX];
if (path.len >= (int) sizeof(path_zt))
return -1;
memcpy(path_zt, path.ptr, path.len);
path_zt[path.len] = '\0';
#ifdef __linux__
if (realpath(path_zt, dst) == NULL)
return -1;
#endif
#ifdef _WIN32
if (_fullpath(path_zt, dst, PATH_MAX) == NULL)
return -1;
#endif
size_t path_len = strlen(dst);
if (path_len > 0 && dst[path_len-1] == '/')
dst[path_len-1] = '\0';
return 0;
}
static int file_read_all(string path, string *data)
{
Handle fd;
int ret = file_open(path, &fd);
if (ret < 0)
return -1;
size_t len;
ret = file_size(fd, &len);
if (ret < 0) {
file_close(fd);
return -1;
}
char *dst = malloc(len);
if (dst == NULL) {
file_close(fd);
return -1;
}
int copied = 0;
while ((size_t) copied < len) {
ret = file_read(fd, dst + copied, len - copied);
if (ret < 0) {
file_close(fd);
return -1;
}
copied += ret;
}
*data = (string) { dst, len };
file_close(fd);
return 0;
}
//////////////////////////////////////////////////////////////////////////
// BYTE QUEUE
//////////////////////////////////////////////////////////////////////////
// This is the implementation of a byte queue useful
// for systems that need to process engs of bytes.
//
// It features sticky errors, a zero-copy interface,
// and a safe mechanism to patch previously written
// bytes.
//
// Only up to 4GB of data can be stored at once.
typedef struct {
uint8_t *ptr;
size_t len;
} ByteView;
typedef struct {
uint64_t curs;
uint8_t* data;
uint32_t head;
uint32_t size;
uint32_t used;
uint32_t limit;
uint8_t* read_target;
uint32_t read_target_size;
int flags;
} ByteQueue;
typedef uint64_t ByteQueueOffset;
enum {
BYTE_QUEUE_ERROR = 1 << 0,
BYTE_QUEUE_READ = 1 << 1,
BYTE_QUEUE_WRITE = 1 << 2,
};
static void *mymalloc(ByteQueue *queue, uint32_t len)
{
(void) queue;
return malloc(len);
}
static void myfree(ByteQueue *queue, void *ptr, uint32_t len)
{
(void) queue;
(void) len,
free(ptr);
}
// Initialize the queue
static void byte_queue_init(ByteQueue *queue, uint32_t limit)
{
queue->flags = 0;
queue->head = 0;
queue->size = 0;
queue->used = 0;
queue->curs = 0;
queue->limit = limit;
queue->data = NULL;
queue->read_target = NULL;
}
// Deinitialize the queue
static void byte_queue_free(ByteQueue *queue)
{
if (queue->read_target) {
if (queue->read_target != queue->data)
myfree(queue, queue->read_target, queue->read_target_size);
queue->read_target = NULL;
queue->read_target_size = 0;
}
myfree(queue, queue->data, queue->size);
queue->data = NULL;
}
static int byte_queue_error(ByteQueue *queue)
{
return queue->flags & BYTE_QUEUE_ERROR;
}
static int byte_queue_empty(ByteQueue *queue)
{
return queue->used == 0;
}
static int byte_queue_full(ByteQueue *queue)
{
return queue->used == queue->limit;
}
// Start a read operation on the queue.
//
// This function returnes the pointer to the memory region containing the bytes
// to read. Callers can't read more than [*len] bytes from it. To complete the
// read, the [byte_queue_read_ack] function must be called with the number of
// bytes that were acknowledged by the caller.
//
// Note:
// - You can't have more than one pending read.
static ByteView byte_queue_read_buf(ByteQueue *queue)
{
if (queue->flags & BYTE_QUEUE_ERROR)
return (ByteView) {NULL, 0};
assert((queue->flags & BYTE_QUEUE_READ) == 0);
queue->flags |= BYTE_QUEUE_READ;
queue->read_target = queue->data;
queue->read_target_size = queue->size;
if (queue->data == NULL)
return (ByteView) {NULL, 0};
return (ByteView) { queue->data + queue->head, queue->used };
}
// Complete a previously started operation on the queue.
static void byte_queue_read_ack(ByteQueue *queue, uint32_t num)
{
if (queue->flags & BYTE_QUEUE_ERROR)
return;
if ((queue->flags & BYTE_QUEUE_READ) == 0)
return;
queue->flags &= ~BYTE_QUEUE_READ;
assert((uint32_t) num <= queue->used);
queue->head += (uint32_t) num;
queue->used -= (uint32_t) num;
queue->curs += (uint32_t) num;
if (queue->read_target) {
if (queue->read_target != queue->data)
myfree(queue, queue->read_target, queue->read_target_size);
queue->read_target = NULL;
queue->read_target_size = 0;
}
}
static ByteView byte_queue_write_buf(ByteQueue *queue)
{
if ((queue->flags & BYTE_QUEUE_ERROR) || queue->data == NULL)
return (ByteView) {NULL, 0};
assert((queue->flags & BYTE_QUEUE_WRITE) == 0);
queue->flags |= BYTE_QUEUE_WRITE;
return (ByteView) {
queue->data + (queue->head + queue->used),
queue->size - (queue->head + queue->used),
};
}
static void byte_queue_write_ack(ByteQueue *queue, uint32_t num)
{
if (queue->flags & BYTE_QUEUE_ERROR)
return;
if ((queue->flags & BYTE_QUEUE_WRITE) == 0)
return;
queue->flags &= ~BYTE_QUEUE_WRITE;
queue->used += num;
}
// Sets the minimum capacity for the next write operation
// and returns 1 if the content of the queue was moved, else
// 0 is returned.
//
// You must not call this function while a write is pending.
// In other words, you must do this:
//
// byte_queue_write_setmincap(queue, mincap);
// dst = byte_queue_write_buf(queue, &cap);
// ...
// byte_queue_write_ack(num);
//
// And NOT this:
//
// dst = byte_queue_write_buf(queue, &cap);
// byte_queue_write_setmincap(queue, mincap); <-- BAD
// ...
// byte_queue_write_ack(num);
//
static int byte_queue_write_setmincap(ByteQueue *queue, uint32_t mincap)
{
// Sticky error
if (queue->flags & BYTE_QUEUE_ERROR)
return 0;
// In general, the queue's contents look like this:
//
// size
// v
// [___xxxxxxxxxxxx________]
// ^ ^ ^
// 0 head head + used
//
// This function needs to make sure that at least [mincap]
// bytes are available on the right side of the content.
//
// We have 3 cases:
//
// 1) If there is enough memory already, this function doesn't
// need to do anything.
//
// 2) If there isn't enough memory on the right but there is
// enough free memory if we cound the left unused region,
// then the content is moved back to the
// start of the buffer.
//
// 3) If there isn't enough memory considering both sides, this
// function needs to allocate a new buffer.
//
// If there are pending read or write operations, the application
// is holding pointers to the buffer, so we need to make sure
// to not invalidate them. The only real problem is pending reads
// since this function can only be called before starting a write
// opearation.
//
// To avoid invalidating the read pointer when we allocate a new
// buffer, we don't free the old buffer. Instead, we store the
// pointer in the "old" field so that the read ack function can
// free it.
//
// To avoid invalidating the pointer when we are moving back the
// content since there is enough memory at the start of the buffer,
// we just avoid that. Even if there is enough memory considering
// left and right free regions, we allocate a new buffer.
assert((queue->flags & BYTE_QUEUE_WRITE) == 0);
uint32_t total_free_space = queue->size - queue->used;
uint32_t free_space_after_data = queue->size - queue->used - queue->head;
int moved = 0;
if (free_space_after_data < mincap) {
if (total_free_space < mincap || (queue->read_target == queue->data)) {
// Resize required
if (queue->used + mincap > queue->limit) {
queue->flags |= BYTE_QUEUE_ERROR;
return 0;
}
uint32_t size;
if (queue->size > UINT32_MAX / 2)
size = UINT32_MAX;
else
size = 2 * queue->size;
if (size < queue->used + mincap)
size = queue->used + mincap;
if (size > queue->limit)
size = queue->limit;
uint8_t *data = mymalloc(queue, size);
if (!data) {
queue->flags |= BYTE_QUEUE_ERROR;
return 0;
}
if (queue->used > 0)
memcpy(data, queue->data + queue->head, queue->used);
if (queue->read_target != queue->data)
myfree(queue, queue->data, queue->size);
queue->data = data;
queue->head = 0;
queue->size = size;
} else {
// Move required
memmove(queue->data, queue->data + queue->head, queue->used);
queue->head = 0;
}
moved = 1;
}
return moved;
}
static void byte_queue_write(ByteQueue *queue, void *ptr, uint32_t len)
{
byte_queue_write_setmincap(queue, len);
ByteView dst = byte_queue_write_buf(queue);
if (dst.ptr) {
memcpy(dst.ptr, ptr, len);
byte_queue_write_ack(queue, len);
}
}
static ByteQueueOffset byte_queue_offset(ByteQueue *queue)
{
if (queue->flags & BYTE_QUEUE_ERROR)
return (ByteQueueOffset) { 0 };
return (ByteQueueOffset) { queue->curs + queue->used };
}
static uint32_t byte_queue_size_from_offset(ByteQueue *queue, ByteQueueOffset off)
{
return queue->curs + queue->used - off;
}
static void byte_queue_patch(ByteQueue *queue, ByteQueueOffset off,
void *src, uint32_t len)
{
if (queue->flags & BYTE_QUEUE_ERROR)
return;
// Check that the offset is in range
assert(off >= queue->curs && off - queue->curs < queue->used);
// Check that the length is in range
assert(len <= queue->used - (off - queue->curs));
// Perform the patch
uint8_t *dst = queue->data + queue->head + (off - queue->curs);
memcpy(dst, src, len);
}
static void byte_queue_remove_from_offset(ByteQueue *queue, ByteQueueOffset offset)
{
if (queue->flags & BYTE_QUEUE_ERROR)
return;
uint64_t num = (queue->curs + queue->used) - offset;
assert(num <= queue->used);
queue->used -= num;
}
//////////////////////////////////////////////////////////////////////////
// SERIALIZATION
//////////////////////////////////////////////////////////////////////////
enum {
// Client -> Metadata server
MESSAGE_TYPE_CREATE,
MESSAGE_TYPE_DELETE,
MESSAGE_TYPE_LIST,
MESSAGE_TYPE_READ,
MESSAGE_TYPE_WRITE,
// Client -> Chunk server
MESSAGE_TYPE_CREATE_CHUNK,
MESSAGE_TYPE_UPLOAD_CHUNK,
MESSAGE_TYPE_DOWNLOAD_CHUNK,
// Metadata server -> Client
MESSAGE_TYPE_CREATE_ERROR,
MESSAGE_TYPE_CREATE_SUCCESS,
MESSAGE_TYPE_DELETE_ERROR,
MESSAGE_TYPE_DELETE_SUCCESS,
MESSAGE_TYPE_LIST_ERROR,
MESSAGE_TYPE_LIST_SUCCESS,
MESSAGE_TYPE_READ_ERROR,
MESSAGE_TYPE_READ_SUCCESS,
MESSAGE_TYPE_WRITE_ERROR,
MESSAGE_TYPE_WRITE_SUCCESS,
// Metadata server -> Chunk server
MESSAGE_TYPE_STATE_UPDATE,
MESSAGE_TYPE_DOWNLOAD_LOCATIONS,
// Chunk server -> Metadata server
MESSAGE_TYPE_AUTH,
MESSAGE_TYPE_STATE_UPDATE_ERROR,
MESSAGE_TYPE_STATE_UPDATE_SUCCESS,
// Chunk server -> Client
MESSAGE_TYPE_CREATE_CHUNK_ERROR,
MESSAGE_TYPE_CREATE_CHUNK_SUCCESS,
MESSAGE_TYPE_UPLOAD_CHUNK_ERROR,
MESSAGE_TYPE_UPLOAD_CHUNK_SUCCESS,
MESSAGE_TYPE_DOWNLOAD_CHUNK_ERROR,
MESSAGE_TYPE_DOWNLOAD_CHUNK_SUCCESS,
};
#define MESSAGE_VERSION 1
typedef struct {
uint8_t *src;
int len;
int cur;
} BinaryReader;
typedef struct {
uint16_t version;
uint16_t type;
uint32_t length;
} MessageHeader;
typedef struct {
ByteQueue *output;
ByteQueueOffset start;
ByteQueueOffset patch;
} MessageWriter;
static bool binary_read(BinaryReader *reader, void *dst, int len)
{
if (reader->len - reader->cur < len)
return false;
if (dst)
memcpy(dst, reader->src + reader->cur, len);
reader->cur += len;
return true;
}
static void message_writer_init(MessageWriter *writer, ByteQueue *output, uint16_t type)
{
uint16_t version = MESSAGE_VERSION;
uint16_t dummy = 0; // Dummy value
writer->output = output;
writer->start = byte_queue_offset(output);
byte_queue_write(output, &version, sizeof(version));
byte_queue_write(output, &type, sizeof(type));
writer->patch = byte_queue_offset(output);
byte_queue_write(output, &dummy, sizeof(dummy));
}
static bool message_writer_free(MessageWriter *writer)
{
uint32_t length = byte_queue_size_from_offset(writer->output, writer->start);
byte_queue_patch(writer->output, writer->patch, &length, sizeof(length));
if (byte_queue_error(writer->output))
return false;
return true;
}
static void message_write(MessageWriter *writer, void *mem, int len)
{
byte_queue_write(writer->output, mem, len);
}
static int message_peek(ByteView msg, uint16_t *type, uint32_t *len)
{
if (msg.len < (int) sizeof(MessageHeader))
return 0;
MessageHeader header;
memcpy(&header, msg.ptr, sizeof(header));
// (We ignore endianess for now)
if (header.version != MESSAGE_VERSION)
return -1;
if (header.length > msg.len)
return 0;
if (type) *type = header.type;
if (len) *len = header.length;
return 1;
}
//////////////////////////////////////////////////////////////////////////
// ASYNCHRONOUS TCP
//////////////////////////////////////////////////////////////////////////
#define MAX_CONNS 512
typedef enum {
EVENT_MESSAGE,
EVENT_CONNECT,
EVENT_DISCONNECT,
} EventType;
typedef struct {
EventType type;
int conn_idx;
} Event;
typedef struct {
uint32_t data;
} IPv4;
typedef struct {
uint16_t data[8];
} IPv6;
typedef struct {
union {
IPv4 ipv4;
IPv6 ipv6;
};
bool is_ipv4;
uint16_t port;
} Address;
typedef struct {
SOCKET fd;
int tag;
bool connecting;
bool closing;
uint32_t msglen;
ByteQueue input;
ByteQueue output;
} Connection;
typedef struct {
SOCKET listen_fd;
int num_conns;
Connection conns[MAX_CONNS];
} TCP;
static bool addr_eql(Address a, Address b)
{
if (a.is_ipv4 != b.is_ipv4)
return false;
if (a.port != b.port)
return false;
if (a.is_ipv4) {
if (memcmp(&a.ipv4, &b.ipv4, sizeof(a.ipv4)))
return false;
} else {
if (memcmp(&a.ipv6, &b.ipv6, sizeof(a.ipv6)))
return false;
}
return true;
}
static SOCKET create_listen_socket(char *addr, uint16_t port)
{
SOCKET fd = socket(AF_INET, SOCK_STREAM, 0);
if (fd == INVALID_SOCKET)
return INVALID_SOCKET;
struct sockaddr_in bind_buf;
bind_buf.sin_family = AF_INET;
bind_buf.sin_port = htons(port);
if (inet_pton(AF_INET, addr, &bind_buf.sin_addr) != 1)
return INVALID_SOCKET;
if (bind(fd, (struct sockaddr*) &bind_buf, sizeof(bind_buf)))
return INVALID_SOCKET;
int backlog = 32;
if (listen(fd, backlog) < 0)
return INVALID_SOCKET;
return fd;
}
static void conn_init(Connection *conn, SOCKET fd, bool connecting)
{
conn->fd = fd;
conn->tag = -1;
conn->connecting = connecting;
conn->closing = false;
conn->msglen = 0;
byte_queue_init(&conn->input, 1<<20);
byte_queue_init(&conn->output, 1<<20);
}
static void conn_free(Connection *conn)
{
CLOSE_SOCKET(conn->fd);
byte_queue_free(&conn->input);
byte_queue_free(&conn->output);
}
static int conn_events(Connection *conn)
{
int events = 0;
if (conn->connecting)
events |= POLLOUT;
else {
assert(!byte_queue_full(&conn->input));
if (!conn->closing)
events |= POLLIN;
if (!byte_queue_empty(&conn->output))
events |= POLLOUT;
}
return events;
}
static void tcp_context_init(TCP *tcp)
{
tcp->listen_fd = INVALID_SOCKET;
tcp->num_conns = 0;
}
static void tcp_context_free(TCP *tcp)
{
if (tcp->listen_fd != INVALID_SOCKET)
CLOSE_SOCKET(tcp->listen_fd);
}
static int tcp_listen(TCP *tcp, char *addr, uint16_t port)
{
SOCKET listen_fd = create_listen_socket(addr, port);
if (listen_fd == INVALID_SOCKET)
return -1;
tcp->listen_fd = listen_fd;
return 0;
}
static int tcp_next_message(TCP *tcp, int conn_idx, ByteView *msg, uint16_t *type)
{
*msg = byte_queue_read_buf(&tcp->conns[conn_idx].input);
uint32_t len;
int ret = message_peek(*msg, type, &len);
// Invalid message?
if (ret < 0) {
byte_queue_read_ack(&tcp->conns[conn_idx].input, 0);
return -1;
}
// Still buffering header?
if (ret == 0) {
byte_queue_read_ack(&tcp->conns[conn_idx].input, 0);
if (byte_queue_full(&tcp->conns[conn_idx].input))
return -1;
return 0;
}
// Message received
assert(ret > 0);
msg->len = len;
tcp->conns[conn_idx].msglen = len;
return 1;
}
static void tcp_consume_message(TCP *tcp, int conn_idx)
{
byte_queue_read_ack(&tcp->conns[conn_idx].input, tcp->conns[conn_idx].msglen);
tcp->conns[conn_idx].msglen = 0;
}
// The "events" array must be an array of capacity MAX_CONNS+1
static int tcp_process_events(TCP *tcp, Event *events)
{
struct pollfd polled[MAX_CONNS + 1];
void *contexts[MAX_CONNS + 1];
int num_polled = 0;
if (tcp->listen_fd != INVALID_SOCKET && tcp->num_conns < MAX_CONNS) {
polled[num_polled].fd = tcp->listen_fd;
polled[num_polled].events = POLLIN;
polled[num_polled].revents = 0;
contexts[num_polled] = NULL;
num_polled++;
}
for (int i = 0; i < tcp->num_conns; i++) {
int events = conn_events(&tcp->conns[i]);
if (events) {
polled[num_polled].fd = tcp->conns[i].fd;
polled[num_polled].events = events;
polled[num_polled].revents = 0;
contexts[num_polled] = &tcp->conns[i];
num_polled++;
}
}
POLL(polled, num_polled, -1);
bool removed[MAX_CONNS+1];
int num_events = 0;
for (int i = 0; i < num_polled; i++) {
if (polled[i].fd == tcp->listen_fd) {
SOCKET new_fd = accept(tcp->listen_fd, NULL, NULL);
if (new_fd != INVALID_SOCKET) {
events[num_events++] = (Event) { EVENT_CONNECT, tcp->num_conns };
conn_init(&tcp->conns[tcp->num_conns++], new_fd, false);
}
} else {
Connection *conn = contexts[i];
bool defer_close = false;
bool defer_ready = false;
if (conn->connecting) {
// TODO: handle error event flags
if (polled[i].revents & POLLOUT) {
int err = 0;
socklen_t len = sizeof(err);
if (getsockopt(conn->fd, SOL_SOCKET, SO_ERROR, (void*) &err, &len) < 0 || err != 0)
defer_close = true;
else {
conn->connecting = false;
events[num_events++] = (Event) { EVENT_CONNECT, conn - tcp->conns };
}
}
} else {
if (polled[i].revents & POLLIN) {
ByteView buf = byte_queue_write_buf(&conn->input);
int num = recv(conn->fd, (char*) buf.ptr, buf.len, 0);
if (num == 0)
defer_close = true;
else if (num < 0) {
if (errno != EINTR && errno != EWOULDBLOCK && errno != EAGAIN)
defer_close = true;
num = 0;
}
byte_queue_write_ack(&conn->input, num);
ByteView msg = byte_queue_read_buf(&conn->input);
int ret = message_peek(msg, NULL, NULL);
if (ret < 0) {
// Invalid message
byte_queue_read_ack(&conn->input, 0);
defer_close = true;
} else if (ret == 0) {
// Still buffering
byte_queue_read_ack(&conn->input, 0);
if (byte_queue_full(&conn->input))
defer_close = true;
} else {
// Message received
assert(ret > 0);
defer_ready = true;
}
}
if (polled[i].revents & POLLOUT) {
ByteView buf = byte_queue_read_buf(&conn->output);
int num = send(conn->fd, (char*) buf.ptr, buf.len, 0);
if (num < 0) {
if (errno != EINTR && errno != EWOULDBLOCK && errno != EAGAIN)
defer_close = true;
num = 0;
}
byte_queue_read_ack(&conn->output, num);
if (conn->closing && byte_queue_empty(&conn->output))
defer_close = true;
}
}
removed[i] = defer_close;
if (0) {}
else if (defer_close) events[num_events++] = (Event) { EVENT_DISCONNECT, conn - tcp->conns };
else if (defer_ready) events[num_events++] = (Event) { EVENT_MESSAGE, conn - tcp->conns };
}
}
for (int i = 0; i < tcp->num_conns; i++)
if (removed[i]) {
conn_free(&tcp->conns[i]);
tcp->conns[i] = tcp->conns[--tcp->num_conns];
}
return num_events;
}
static ByteQueue *tcp_output_buffer(TCP *tcp, int conn_idx)
{
return &tcp->conns[conn_idx].output;
}
static int tcp_connect(TCP *tcp, Address addr, int tag, ByteQueue **output)
{
if (tcp->num_conns == MAX_CONNS)
return -1;
int conn_idx = tcp->num_conns;
SOCKET fd = socket(AF_INET, SOCK_STREAM, 0);
if (fd == INVALID_SOCKET)
return -1;
int ret;
if (addr.is_ipv4) {
struct sockaddr_in buf;
buf.sin_family = AF_INET;
buf.sin_port = htons(addr.port);
memcpy(&buf.sin_addr, &addr.ipv4, sizeof(IPv4));
ret = connect(fd, (struct sockaddr*) &buf, sizeof(buf));
} else {
struct sockaddr_in6 buf;
buf.sin6_family = AF_INET6;
buf.sin6_port = htons(addr.port);
memcpy(&buf.sin6_addr, &addr.ipv6, sizeof(IPv6));
ret = connect(fd, (struct sockaddr*) &buf, sizeof(buf));
}
bool connecting;
if (ret == 0) {
connecting = false;
} else {
if (errno != EINPROGRESS) {
CLOSE_SOCKET(fd);
return -1;
}
connecting = true;
}
conn_init(&tcp->conns[conn_idx], fd, connecting);
tcp->conns[conn_idx].tag = tag;
if (output)
*output = &tcp->conns[conn_idx].output;
tcp->num_conns++;
return 0;
}
static void tcp_close(TCP *tcp, int conn_idx)
{
tcp->conns[conn_idx].closing = true;
}
static void tcp_set_tag(TCP *tcp, int conn_idx, int tag)
{
tcp->conns[conn_idx].tag = tag;
}
static int tcp_get_tag(TCP *tcp, int conn_idx)
{
return tcp->conns[conn_idx].tag;
}
//////////////////////////////////////////////////////////////////////////
// FILE TREE
//////////////////////////////////////////////////////////////////////////
#ifdef BUILD_METADATA_SERVER
enum {
FILETREE_NOMEM = -1,
FILETREE_NOENT = -2,
FILETREE_NOTDIR = -3,
FILETREE_ISDIR = -4,
FILETREE_EXISTS = -5,
FILETREE_BADPATH = -6,
FILETREE_BADOP = -7,
};
typedef struct Entity Entity;
typedef struct {
uint64_t chunk_size;
uint64_t num_chunks;
SHA256 *chunks;
} File;
typedef struct {
uint64_t max_children;
uint64_t num_children;
Entity *children;
} Dir;
struct Entity {
char name[1<<8];
uint16_t name_len;
bool is_dir;
union {
Dir d;
File f;
};
};
typedef struct {
Entity root;
} FileTree;
typedef struct {
char name[1<<8];
int name_len;
bool is_dir;
} ListItem;
#define MAX_COMPS 32
static int parse_path(string path, string *comps, int max)
{
if (path.len > 0 && path.ptr[0] == '/') {
path.ptr++;
path.len--;
if (path.len == 0)
return 0; // Absolute paths with no components are allowed
}
int num = 0;
uint32_t i = 0;
for (;;) {
uint32_t off = i;
while (i < (uint32_t) path.len && path.ptr[i] != '/')
i++;
uint32_t len = i - off;
if (len == 0)
return -1; // Empty component
string comp = { path.ptr + off, len };
if (comp.len == 2 && comp.ptr[0] == '.' && comp.ptr[1] == '.') {
if (num == 0)
return -1; // Path references the parent of the root. TODO: What if the path is absolute?
num--;
} else if (comp.len != 1 || comp.ptr[0] != '.') {
if (num == max)
return -1; // To many components
comps[num++] = comp;
}
if (i == (uint32_t) path.len)
break;
assert(path.ptr[i] == '/');
i++;
if (i == (uint32_t) path.len)
break;
}
return num;
}
static int dir_find(Dir *parent, string name)
{
for (uint64_t i = 0; i < parent->num_children; i++)
if (streq((string) { parent->children[i].name, parent->children[i].name_len }, name))
return i;
return -1;
}
static Entity *resolve_path(Entity *root, string *comps, int num_comps)
{
assert(root->is_dir);
Entity *current = root;
for (int i = 0; i < num_comps; i++) {
if (!current->is_dir)
return NULL;
int j = dir_find(&current->d, comps[i]);
if (j == -1)
return NULL;
current = &current->d.children[j];
}
return current;
}
static void entity_free(Entity *e);
static bool entity_uses_hash(Entity *e, SHA256 hash);
static void dir_init(Dir *d)
{
d->num_children = 0;
d->max_children = 0;
d->children = NULL;
}
static void dir_free(Dir *d)
{
for (uint64_t i = 0; i < d->num_children; i++)
entity_free(&d->children[i]);
free(d->children);
}
static void dir_remove(Dir *d, int idx)
{
d->children[idx] = d->children[--d->num_children];
}
static bool dir_uses_hash(Dir *d, SHA256 hash)
{
for (uint64_t i = 0; i < d->num_children; i++)
if (entity_uses_hash(&d->children[i], hash))
return true;
return false;
}
static void file_init(File *f, uint64_t chunk_size)
{
f->chunk_size = chunk_size;
f->num_chunks = 0;
f->chunks = NULL;
}
static void file_free(File *f)
{
free(f->chunks);
f->chunks = NULL;
}
static bool file_uses_hash(File *f, SHA256 hash)
{
for (uint64_t i = 0; i < f->num_chunks; i++)
if (!memcmp(&f->chunks[i], &hash, sizeof(SHA256)))
return true;
return false;
}
// Fails when the name is too long
static int entity_init(Entity *e, char *name, int name_len,
bool is_dir, uint64_t chunk_size)
{
if (name_len >= (int) sizeof(e->name))
return -1;
memcpy(e->name, name, name_len);
e->name[name_len] = '\0';
e->name_len = (uint16_t) name_len;
e->is_dir = is_dir;
if (is_dir)
dir_init(&e->d);
else
file_init(&e->f, chunk_size);
return 0;
}
static void entity_free(Entity *e)
{
if (e->is_dir)
dir_free(&e->d);
else
file_free(&e->f);
}
static bool entity_uses_hash(Entity *e, SHA256 hash)
{
if (e->is_dir)
return dir_uses_hash(&e->d, hash);
else
return file_uses_hash(&e->f, hash);
}
static int file_tree_init(FileTree *ft)
{
int ret = entity_init(&ft->root, "", 0, true, 0);
if (ret < 0) return -1;
return 0;
}
static void file_tree_free(FileTree *ft)
{
entity_free(&ft->root);
}
static bool file_tree_uses_hash(FileTree *ft, SHA256 hash)
{
return entity_uses_hash(&ft->root, hash);
}
static int file_tree_list(FileTree *ft, string path,
ListItem *items, int max_items)
{
int num_comps;
string comps[MAX_COMPS];
num_comps = parse_path(path, comps, MAX_COMPS);
if (num_comps < 0)
return FILETREE_BADPATH;
Entity *e = resolve_path(&ft->root, comps, num_comps);
if (e == NULL)
return FILETREE_NOENT;
if (!e->is_dir)
return FILETREE_NOTDIR;
Dir *d = &e->d;
int num_items = d->num_children;
if (num_items > max_items) num_items = max_items;
for (int i = 0; i < num_items; i++) {
Entity *c = &d->children[i];
int name_cpy = c->name_len;
if (name_cpy > (int) sizeof(items[i].name)-1)
name_cpy = (int) sizeof(items[i].name)-1;
memcpy(items[i].name, c->name, name_cpy);
items[i].name[name_cpy] = '\0';
items[i].name_len = name_cpy;
items[i].is_dir = c->is_dir;
}
return d->num_children;
}
static int
file_tree_create_entity(FileTree *ft, string path,
bool is_dir, uint64_t chunk_size)
{
int num_comps;
string comps[MAX_COMPS];
num_comps = parse_path(path, comps, MAX_COMPS);
if (num_comps < 0)
// Couldn't parse path
return FILETREE_BADPATH;
if (num_comps == 0)
// Path is empty, which means the caller is referencing the root,
// which exists already.
return FILETREE_EXISTS;
// Resolve the path up to the second last component
Entity *e = resolve_path(&ft->root, comps, num_comps-1);
if (e == NULL)
// Parent directory doesn't exist
return FILETREE_NOENT;
if (!e->is_dir)
// Parent entity is not a directory
return FILETREE_NOTDIR;
string name = comps[num_comps-1];
if (dir_find(&e->d, name) != -1)
return FILETREE_EXISTS;
Dir *d = &e->d;
if (d->num_children == d->max_children) {
int new_max = 2 * d->max_children;
if (new_max == 0)
new_max = 8;
Entity *p = malloc(sizeof(Entity) * new_max);
if (p == NULL)
return FILETREE_NOMEM;
for (uint64_t i = 0; i < d->num_children; i++)
p[i] = d->children[i];
free(d->children);
d->children = p;
d->max_children = new_max;
}
Entity *c = &d->children[d->num_children];
int ret = entity_init(c, (char*) name.ptr, name.len, is_dir, chunk_size);
if (ret < 0)
// Invalid name for the new file
return FILETREE_BADPATH;
d->num_children++;
return 0;
}
static int
file_tree_delete_entity(FileTree *ft, string path)
{
int num_comps;
string comps[MAX_COMPS];
num_comps = parse_path(path, comps, MAX_COMPS);
if (num_comps < 0)
return FILETREE_BADPATH;
if (num_comps == 0)
return FILETREE_BADOP;
Entity *e = resolve_path(&ft->root, comps, num_comps-1);
if (e == NULL)
return FILETREE_NOENT;
if (!e->is_dir)
return FILETREE_NOTDIR;
int i = dir_find(&e->d, comps[num_comps-1]);
if (i == -1)
return FILETREE_NOENT;
dir_remove(&e->d, i);
return 0;
}
static int file_tree_write(FileTree *ft, string path,
uint64_t off, uint64_t len, SHA256 *prev_hashes,
SHA256 *hashes)
{
int num_comps;
string comps[MAX_COMPS];
num_comps = parse_path(path, comps, MAX_COMPS);
if (num_comps < 0)
return -1; // TODO: proper error code
Entity *e = resolve_path(&ft->root, comps, num_comps);
if (e == NULL)
return -1; // TODO: proper error code
if (e->is_dir)
return -1; // TODO: proper error code
File *f = &e->f;
uint64_t first_chunk_index = off / f->chunk_size;
uint64_t last_chunk_index = (off + len - 1) / f->chunk_size;
if (last_chunk_index >= f->num_chunks) {
SHA256 *new_chunks = malloc((last_chunk_index+1) * sizeof(SHA256));
if (new_chunks == NULL)
return -1; // TODO: proper error code
if (f->chunks) {
if (f->num_chunks > 0)
memcpy(new_chunks, f->chunks, f->num_chunks);
free(f->chunks);
}
f->chunks = new_chunks;
f->num_chunks = last_chunk_index+1;
for (uint64_t i = f->num_chunks; i < last_chunk_index+1; i++)
memset(&f->chunks[i], 0, sizeof(SHA256));
}
for (uint64_t i = first_chunk_index; i <= last_chunk_index; i++)
if (memcmp(&f->chunks[i], &prev_hashes[i - first_chunk_index], sizeof(SHA256)))
return -1;
for (uint64_t i = first_chunk_index; i <= last_chunk_index; i++)
f->chunks[i] = hashes[i - first_chunk_index];
return 0;
}
#define ZERO_HASH ((SHA256) { .data={0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 } })
static int file_tree_read(FileTree *ft, string path,
uint64_t off, uint64_t len, uint64_t *chunk_size,
SHA256 *hashes, int max_hashes)
{
int num_comps;
string comps[MAX_COMPS];
num_comps = parse_path(path, comps, MAX_COMPS);
if (num_comps < 0)
return FILETREE_BADPATH;
Entity *e = resolve_path(&ft->root, comps, num_comps);
if (e == NULL)
return FILETREE_NOENT;
if (e->is_dir)
return FILETREE_NOTDIR;
File *f = &e->f;
if (len == 0)
return 0;
*chunk_size = f->chunk_size;
uint64_t first_chunk_index = off / f->chunk_size;
uint64_t last_chunk_index = (off + len - 1) / f->chunk_size;
int num_hashes = 0;
for (uint32_t i = first_chunk_index; i <= last_chunk_index; i++) {
SHA256 hash;
if (i >= f->num_chunks)
hash = ZERO_HASH;
else
hash = f->chunks[i];
if (num_hashes < max_hashes)
hashes[num_hashes] = hash;
num_hashes++;
}
return num_hashes;
}
static string file_tree_strerror(int code)
{
switch (code) {
case FILETREE_NOMEM : return S("Out of memory");
case FILETREE_NOENT : return S("No such file or directory");
case FILETREE_NOTDIR : return S("Entity is not a directory");
case FILETREE_ISDIR : return S("Entity is a directory");
case FILETREE_EXISTS : return S("File or directory already exists");
case FILETREE_BADPATH: return S("Invalid path");
case FILETREE_BADOP : return S("Invalid operation");
default:break;
}
return S("Unknown error");
}
#endif // BUILD_METADATA_SERVER
//////////////////////////////////////////////////////////////////////////
// METADATA SERVER
//////////////////////////////////////////////////////////////////////////
#ifdef BUILD_METADATA_SERVER
#define MAX_SERVER_ADDRS 8
#define MAX_CHUNK_SERVERS 32
#define CONNECTION_TAG_CLIENT -1
#define CONNECTION_TAG_UNKNOWN -2
typedef struct {
int count;
int capacity;
SHA256 *items;
SHA256 items_hash;
} ChunkList;
typedef struct {
bool auth;
int num_addrs;
Address addrs[MAX_SERVER_ADDRS];
// Chunks held by the chunk server during
// the last update
ChunkList old_list;
// Chunks added to the chunk server since
// the last update
ChunkList add_list;
// Chunks removed from the chunk server
// since the last update
ChunkList rem_list;
} ChunkServer;
typedef struct {
int num_chunk_servers;
TCP tcp;
FileTree file_tree;
ChunkServer chunk_servers[MAX_CHUNK_SERVERS];
} ProgramState;
static void chunk_list_init(ChunkList *chunk_list)
{
chunk_list->count = 0;
chunk_list->capacity = 0;
chunk_list->items = NULL;
memset(&chunk_list->items_hash, 0, sizeof(SHA256));
}
static void chunk_list_free(ChunkList *chunk_list)
{
free(chunk_list->items);
}
static int chunk_list_insert(ChunkList *chunk_list, SHA256 hash)
{
// Avoid duplicates
for (int i = 0; i < chunk_list->count; i++)
if (!memcmp(&chunk_list->items[i], &hash, sizeof(SHA256)))
return 0; // Already present
if (chunk_list->count == chunk_list->capacity) {
int new_capacity = chunk_list->capacity ? chunk_list->capacity * 2 : 16;
SHA256 *new_items = realloc(chunk_list->items, new_capacity * sizeof(SHA256));
if (new_items == NULL)
return -1;
chunk_list->items = new_items;
chunk_list->capacity = new_capacity;
}
chunk_list->items[chunk_list->count++] = hash;
return 0;
}
static bool chunk_list_contains(ChunkList *chunk_list, SHA256 hash)
{
for (int j = 0; j < chunk_list->count; j++)
if (!memcmp(&hash, &chunk_list->items[j], sizeof(SHA256)))
return true;
return false;
}
static void chunk_server_init(ChunkServer *chunk_server)
{
chunk_server->auth = false;
chunk_server->num_addrs = 0;
chunk_list_init(&chunk_server->old_list);
chunk_list_init(&chunk_server->add_list);
chunk_list_init(&chunk_server->rem_list);
}
static void chunk_server_free(ChunkServer *chunk_server)
{
chunk_list_free(&chunk_server->rem_list);
chunk_list_free(&chunk_server->add_list);
chunk_list_free(&chunk_server->old_list);
}
// Look for a chunk server holding a chunk with the
// given hash. If no such chunk server exists, return -1.
static int choose_server_holding_chunk(ProgramState *state, SHA256 hash)
{
for (int i = 0; i < state->num_chunk_servers; i++)
if (chunk_list_contains(&state->chunk_servers[i].old_list, hash) ||
chunk_list_contains(&state->chunk_servers[i].add_list, hash))
return i;
return -1;
}
// Return the index of the chunk server with less
// chunks, or -1 is no chunk servers are available.
static int choose_server_for_write(ProgramState *state)
{
if (state->num_chunk_servers == 0)
return -1;
int chunk_count = state->chunk_servers[0].old_list.count + state->chunk_servers[0].add_list.count;
int server_index = 0;
for (int i = 1; i < state->num_chunk_servers; i++) {
int tmp = state->chunk_servers[i].old_list.count + state->chunk_servers[i].add_list.count;
if (tmp < chunk_count) {
chunk_count = tmp;
server_index = i;
}
}
return server_index;
}
static int find_chunk_server_by_addr(ProgramState *state, Address addr)
{
for (int i = 0; i < state->num_chunk_servers; i++)
for (int j = 0; j < state->chunk_servers[i].num_addrs; j++)
if (addr_eql(state->chunk_servers[i].addrs[j], addr))
return j;
return -1;
}
// Serialize the list of addresses for the specified
// chunk server.
static void
message_write_server_addr(MessageWriter *writer, ChunkServer *server)
{
uint32_t num_ipv4 = 0;
for (int i = 0; i < server->num_addrs; i++)
if (server->addrs[i].is_ipv4)
num_ipv4++;
message_write(writer, &num_ipv4, sizeof(num_ipv4));
for (int i = 0; i < server->num_addrs; i++)
if (server->addrs[i].is_ipv4) {
message_write(writer, &server->addrs[i].ipv4, sizeof(server->addrs[i].ipv4));
message_write(writer, &server->addrs[i].port, sizeof(server->addrs[i].port));
}
uint32_t num_ipv6 = 0;
for (int i = 0; i < server->num_addrs; i++)
if (!server->addrs[i].is_ipv4)
num_ipv6++;
message_write(writer, &num_ipv6, sizeof(num_ipv6));
for (int i = 0; i < server->num_addrs; i++)
if (!server->addrs[i].is_ipv4) {
message_write(writer, &server->addrs[i].ipv6, sizeof(server->addrs[i].ipv6));
message_write(writer, &server->addrs[i].port, sizeof(server->addrs[i].port));
}
}
static int
process_client_create(ProgramState *state, int conn_idx, ByteView msg)
{
BinaryReader reader = { msg.ptr, msg.len, 0 };
// Read header
if (!binary_read(&reader, NULL, sizeof(MessageHeader)))
return -1;
char path_mem[1<<10];
uint16_t path_len;
if (binary_read(&reader, &path_len, sizeof(path_len)))
return -1;
if (path_len > sizeof(path_mem))
return -2;
if (binary_read(&reader, &path_mem, path_len))
return -1;
string path = { path_mem, path_len };
uint8_t is_dir;
if (binary_read(&reader, &is_dir, sizeof(path_len)))
return -1;
uint32_t chunk_size;
if (is_dir)
chunk_size = 0;
else {
if (binary_read(&reader, &chunk_size, sizeof(chunk_size)))
return -1;
}
// Check that there are no more bytes to read
if (binary_read(&reader, NULL, 1))
return -1;
int ret = file_tree_create_entity(&state->file_tree, path, is_dir, chunk_size);
if (ret < 0) {
string desc = file_tree_strerror(ret);
MessageWriter writer;
ByteQueue *output = tcp_output_buffer(&state->tcp, conn_idx);
message_writer_init(&writer, output, MESSAGE_TYPE_CREATE_ERROR);
uint16_t len = desc.len;
message_write(&writer, &len, sizeof(len));
message_write(&writer, desc.ptr, desc.len);
if (!message_writer_free(&writer))
return -1;
} else {
MessageWriter writer;
ByteQueue *output = tcp_output_buffer(&state->tcp, conn_idx);
message_writer_init(&writer, output, MESSAGE_TYPE_CREATE_SUCCESS);
if (!message_writer_free(&writer))
return -1;
}
return 0;
}
static int
process_client_delete(ProgramState *state, int conn_idx, ByteView msg)
{
BinaryReader reader = { msg.ptr, msg.len, 0 };
// Read header
if (!binary_read(&reader, NULL, sizeof(MessageHeader)))
return -1;
char path_mem[1<<10];
uint16_t path_len;
if (binary_read(&reader, &path_len, sizeof(path_len)))
return -1;
if (path_len > sizeof(path_mem))
return -2;
if (binary_read(&reader, &path_mem, path_len))
return -1;
string path = { path_mem, path_len };
// Check that there are no more bytes to read
if (binary_read(&reader, NULL, 1))
return -1;
int ret = file_tree_delete_entity(&state->file_tree, path);
if (ret < 0) {
string desc = file_tree_strerror(ret);
MessageWriter writer;
ByteQueue *output = tcp_output_buffer(&state->tcp, conn_idx);
message_writer_init(&writer, output, MESSAGE_TYPE_DELETE_ERROR);
uint16_t len = desc.len;
message_write(&writer, &len, sizeof(len));
message_write(&writer, desc.ptr, desc.len);
if (!message_writer_free(&writer))
return -1;
} else {
MessageWriter writer;
ByteQueue *output = tcp_output_buffer(&state->tcp, conn_idx);
message_writer_init(&writer, output, MESSAGE_TYPE_DELETE_SUCCESS);
if (!message_writer_free(&writer))
return -1;
}
return 0;
}
static int
process_client_list(ProgramState *state, int conn_idx, ByteView msg)
{
BinaryReader reader = { msg.ptr, msg.len, 0 };
// Read header
if (!binary_read(&reader, NULL, sizeof(MessageHeader)))
return -1;
char path_mem[1<<10];
uint16_t path_len;
if (binary_read(&reader, &path_len, sizeof(path_len)))
return -1;
if (path_len > sizeof(path_mem))
return -2;
if (binary_read(&reader, &path_mem, path_len))
return -1;
string path = { path_mem, path_len };
// Check that there are no more bytes to read
if (binary_read(&reader, NULL, 1))
return -1;
#define MAX_LIST_SIZE 128
ListItem items[MAX_LIST_SIZE];
int ret = file_tree_list(&state->file_tree, path, items, MAX_LIST_SIZE);
if (ret < 0) {
string desc = file_tree_strerror(ret);
MessageWriter writer;
ByteQueue *output = tcp_output_buffer(&state->tcp, conn_idx);
message_writer_init(&writer, output, MESSAGE_TYPE_LIST_ERROR);
uint16_t len = desc.len;
message_write(&writer, &len, sizeof(len));
message_write(&writer, desc.ptr, desc.len);
if (!message_writer_free(&writer))
return -1;
} else {
MessageWriter writer;
ByteQueue *output = tcp_output_buffer(&state->tcp, conn_idx);
message_writer_init(&writer, output, MESSAGE_TYPE_LIST_SUCCESS);
uint32_t item_count = ret;
uint8_t truncated = 0;
if (ret > MAX_LIST_SIZE) {
truncated = 1;
item_count = MAX_LIST_SIZE;
}
message_write(&writer, &item_count, sizeof(item_count));
message_write(&writer, &truncated, sizeof(truncated));
for (int i = 0; i < ret && i < MAX_LIST_SIZE; i++) {
uint8_t is_dir = items[i].is_dir;
message_write(&writer, &is_dir, sizeof(is_dir));
if (items[i].name_len > UINT16_MAX)
return -1;
uint16_t name_len = items[i].name_len;
message_write(&writer, &name_len, sizeof(name_len));
message_write(&writer, items[i].name, name_len);
}
if (!message_writer_free(&writer))
return -1;
}
return 0;
}
static int
process_client_read(ProgramState *state, int conn_idx, ByteView msg)
{
BinaryReader reader = { msg.ptr, msg.len, 0 };
// Read header
if (!binary_read(&reader, NULL, sizeof(MessageHeader)))
return -1;
char path_mem[1<<10];
uint16_t path_len;
if (binary_read(&reader, &path_len, sizeof(path_len)))
return -1;
if (path_len > sizeof(path_mem))
return -2;
if (binary_read(&reader, &path_mem, path_len))
return -1;
string path = { path_mem, path_len };
uint32_t offset;
if (binary_read(&reader, &offset, sizeof(offset)))
return -1;
uint32_t length;
if (binary_read(&reader, &length, sizeof(length)))
return -1;
// Check that there are no more bytes to read
if (binary_read(&reader, NULL, 1))
return -1;
#define MAX_READ_HASHES 128
uint64_t chunk_size;
SHA256 hashes[MAX_READ_HASHES];
int ret = file_tree_read(&state->file_tree, path, offset, length, &chunk_size, hashes, MAX_READ_HASHES);
if (ret < 0) {
string desc = file_tree_strerror(ret);
MessageWriter writer;
ByteQueue *output = tcp_output_buffer(&state->tcp, conn_idx);
message_writer_init(&writer, output, MESSAGE_TYPE_READ_ERROR);
uint16_t len = desc.len;
message_write(&writer, &len, sizeof(len));
message_write(&writer, desc.ptr, desc.len);
if (!message_writer_free(&writer))
return -1;
} else {
MessageWriter writer;
ByteQueue *output = tcp_output_buffer(&state->tcp, conn_idx);
message_writer_init(&writer, output, MESSAGE_TYPE_READ_SUCCESS);
uint32_t tmp = chunk_size; // TODO: check overflow
message_write(&writer, &tmp, sizeof(tmp));
uint32_t num_hashes = ret;
message_write(&writer, &num_hashes, sizeof(num_hashes));
for (uint32_t i = 0; i < num_hashes; i++) {
// TODO: This should write the address of 3 servers,
// not just 1.
int j = choose_server_holding_chunk(state, hashes[i]);
if (j < 0) {
// TODO
}
ChunkServer *chunk_server = &state->chunk_servers[j];
assert(chunk_server->auth);
assert(chunk_server->num_addrs > 0);
message_write(&writer, &hashes[i], sizeof(hashes[i]));
message_write_server_addr(&writer, chunk_server);
}
// TODO: This should write the location of 3 servers,
// not just 1.
int write_server_index = choose_server_for_write(state);
if (write_server_index == -1) {
// TODO
}
message_write_server_addr(&writer, &state->chunk_servers[write_server_index]);
if (!message_writer_free(&writer))
return -1;
}
return 0;
}
static int
process_client_write(ProgramState *state, int conn_idx, ByteView msg)
{
BinaryReader reader = { msg.ptr, msg.len, 0 };
// Read header
if (!binary_read(&reader, NULL, sizeof(MessageHeader)))
return -1;
char path_mem[1<<10];
uint16_t path_len;
if (binary_read(&reader, &path_len, sizeof(path_len)))
return -1;
if (path_len > sizeof(path_mem))
return -2;
if (binary_read(&reader, &path_mem, path_len))
return -1;
string path = { path_mem, path_len };
uint32_t offset;
if (binary_read(&reader, &offset, sizeof(offset)))
return -1;
uint32_t length;
if (binary_read(&reader, &length, sizeof(length)))
return -1;
uint32_t num_chunks;
if (binary_read(&reader, &num_chunks, sizeof(num_chunks)))
return -1;
#define MAX_CHUNKS_PER_WRITE 32
Address addrs[MAX_CHUNKS_PER_WRITE];
SHA256 new_hashes[MAX_CHUNKS_PER_WRITE];
SHA256 old_hashes[MAX_CHUNKS_PER_WRITE];
for (uint32_t i = 0; i < num_chunks; i++) {
SHA256 old_hash;
if (binary_read(&reader, &old_hash, sizeof(old_hash)))
return -1;
SHA256 new_hash;
if (binary_read(&reader, &new_hash, sizeof(new_hash)))
return -1;
uint8_t is_ipv4;
if (binary_read(&reader, &is_ipv4, sizeof(is_ipv4)))
return -1;
Address addr;
addr.is_ipv4 = is_ipv4;
if (is_ipv4) {
if (binary_read(&reader, &addr.ipv4, sizeof(addr.ipv4)))
return -1;
} else {
if (binary_read(&reader, &addr.ipv6, sizeof(addr.ipv6)))
return -1;
}
if (binary_read(&reader, &addr.port, sizeof(addr.port)))
return -1;
addrs[i] = addr;
new_hashes[i] = new_hash;
old_hashes[i] = old_hash;
}
// Check that there are no more bytes to read
if (binary_read(&reader, NULL, 1))
return -1;
int ret = file_tree_write(&state->file_tree, path, offset, length, old_hashes, new_hashes);
if (ret < 0) {
string desc = file_tree_strerror(ret);
MessageWriter writer;
ByteQueue *output = tcp_output_buffer(&state->tcp, conn_idx);
message_writer_init(&writer, output, MESSAGE_TYPE_WRITE_ERROR);
uint16_t len = desc.len;
message_write(&writer, &len, sizeof(len));
message_write(&writer, desc.ptr, desc.len);
if (!message_writer_free(&writer))
return -1;
} else {
// TODO: need to check whether chunks that were overwritten
// should be removed or not
for (uint32_t i = 0; i < num_chunks; i++) {
int j = find_chunk_server_by_addr(state, addrs[i]);
if (j == -1)
return -1;
if (!chunk_list_insert(&state->chunk_servers[j].add_list, new_hashes[i]))
return -1;
}
MessageWriter writer;
ByteQueue *output = tcp_output_buffer(&state->tcp, conn_idx);
message_writer_init(&writer, output, MESSAGE_TYPE_WRITE_SUCCESS);
if (!message_writer_free(&writer))
return -1;
}
return 0;
}
static int
process_client_message(ProgramState *state,
int conn_idx, uint8_t type, ByteView msg)
{
switch (type) {
case MESSAGE_TYPE_CREATE: return process_client_create(state, conn_idx, msg);
case MESSAGE_TYPE_DELETE: return process_client_delete(state, conn_idx, msg);
case MESSAGE_TYPE_LIST : return process_client_list (state, conn_idx, msg);
case MESSAGE_TYPE_READ : return process_client_read (state, conn_idx, msg);
case MESSAGE_TYPE_WRITE : return process_client_write (state, conn_idx, msg);
default:break;
}
return -1;
}
static ChunkServer*
chunk_server_from_conn(ProgramState *state, int conn_idx)
{
int tag = tcp_get_tag(&state->tcp, conn_idx);
assert(tag >= 0);
return &state->chunk_servers[tag];
}
static int process_chunk_server_auth(ProgramState *state,
int conn_idx, ByteView msg)
{
ChunkServer *chunk_server = chunk_server_from_conn(state, conn_idx);
chunk_server->num_addrs = 0;
BinaryReader reader = { msg.ptr, msg.len, 0 };
// Read header
if (!binary_read(&reader, NULL, sizeof(MessageHeader)))
return -1;
// Read IPv4s
{
uint32_t num_ipv4;
if (!binary_read(&reader, &num_ipv4, sizeof(num_ipv4)))
return -1;
for (uint32_t i = 0; i < num_ipv4; i++) {
IPv4 ipv4;
if (!binary_read(&reader, &ipv4, sizeof(ipv4)))
return -1;
uint16_t port;
if (!binary_read(&reader, &port, sizeof(port)))
return -1;
if (chunk_server->num_addrs < MAX_SERVER_ADDRS)
chunk_server->addrs[chunk_server->num_addrs++] =
(Address) { .ipv4=ipv4, .is_ipv4=true, .port=port };
}
}
// Read IPv6s
{
uint32_t num_ipv6;
if (!binary_read(&reader, &num_ipv6, sizeof(num_ipv6)))
return -1;
for (uint32_t i = 0; i < num_ipv6; i++) {
IPv6 ipv6;
if (!binary_read(&reader, &ipv6, sizeof(ipv6)))
return -1;
uint16_t port;
if (!binary_read(&reader, &port, sizeof(port)))
return -1;
if (chunk_server->num_addrs < MAX_SERVER_ADDRS)
chunk_server->addrs[chunk_server->num_addrs++] =
(Address) { .is_ipv4=true, .ipv6=ipv6, .port=port };
}
}
// No addresses were wpecified
if (chunk_server->num_addrs == 0)
return -1;
// Check that there are no more bytes to read
if (binary_read(&reader, NULL, 1))
return -1;
chunk_server->auth = true; // TODO: Verify
return 0;
}
static int
process_chunk_server_message(ProgramState *state,
int conn_idx, uint8_t type, ByteView msg)
{
switch (type) {
case MESSAGE_TYPE_AUTH : return process_chunk_server_auth(state, conn_idx, msg);
default:break;
}
return -1;
}
static bool is_chunk_server_message_type(uint16_t type)
{
switch (type) {
case MESSAGE_TYPE_AUTH:
case MESSAGE_TYPE_STATE_UPDATE_ERROR:
case MESSAGE_TYPE_STATE_UPDATE_SUCCESS:
return true;
default:
break;
}
return false;
}
int program_init(ProgramState *state, int argc, char **argv)
{
(void) argc;
(void) argv;
char addr[] = "127.0.0.1";
uint16_t port = 8080;
state->num_chunk_servers = 0;
tcp_context_init(&state->tcp);
int ret = tcp_listen(&state->tcp, addr, port);
if (ret < 0) {
tcp_context_free(&state->tcp);
return -1;
}
ret = file_tree_init(&state->file_tree);
if (ret < 0) {
tcp_context_free(&state->tcp);
return -1;
}
return 0;
}
int program_free(ProgramState *state)
{
file_tree_free(&state->file_tree);
tcp_context_free(&state->tcp);
return 0;
}
int program_step(ProgramState *state)
{
Event events[MAX_CONNS+1];
int num_events = tcp_process_events(&state->tcp, events);
for (int i = 0; i < num_events; i++) {
int conn_idx = events[i].conn_idx;
switch (events[i].type) {
case EVENT_CONNECT:
tcp_set_tag(&state->tcp, conn_idx, CONNECTION_TAG_UNKNOWN);
break;
case EVENT_DISCONNECT:
{
int tag = tcp_get_tag(&state->tcp, conn_idx);
if (tag >= 0) {
chunk_server_free(&state->chunk_servers[tag]);
state->num_chunk_servers--;
}
}
break;
case EVENT_MESSAGE:
{
ByteView msg;
uint16_t msg_type;
while (tcp_next_message(&state->tcp, conn_idx, &msg, &msg_type)) {
if (tcp_get_tag(&state->tcp, conn_idx) == CONNECTION_TAG_UNKNOWN) {
if (is_chunk_server_message_type(msg_type)) {
int chunk_server_idx = state->num_chunk_servers++;
chunk_server_init(&state->chunk_servers[chunk_server_idx]);
tcp_set_tag(&state->tcp, conn_idx, chunk_server_idx);
} else {
tcp_set_tag(&state->tcp, conn_idx, CONNECTION_TAG_CLIENT);
}
}
int ret;
if (tcp_get_tag(&state->tcp, conn_idx) == CONNECTION_TAG_CLIENT)
ret = process_client_message(state, conn_idx, msg_type, msg);
else
ret = process_chunk_server_message(state, conn_idx, msg_type, msg);
if (ret < 0)
tcp_close(&state->tcp, conn_idx);
tcp_consume_message(&state->tcp, conn_idx);
}
}
break;
}
}
return 0;
}
#endif // BUILD_METADATA_SERVER
//////////////////////////////////////////////////////////////////////////
// CHUNK SERVER
//////////////////////////////////////////////////////////////////////////
#ifdef BUILD_CHUNK_SERVER
#define TAG_METADATA_SERVER 1
#define TAG_CHUNK_SERVER 2
#define CHUNK_SERVER_RECONNECT_TIME 10000
typedef struct {
char path[PATH_MAX];
} ChunkStore;
typedef struct {
Address addr;
SHA256 hash;
} PendingDownload;
typedef struct {
int count;
int capacity;
PendingDownload *items;
} PendingDownloadList;
typedef struct {
Address metadata_server_addr;
Time metadata_server_disconnect_time;
TCP tcp;
ChunkStore store;
bool downloading;
PendingDownloadList pending_download_list;
} ProgramState;
static void
pending_download_list_init(PendingDownloadList *list)
{
list->count = 0;
list->capacity = 0;
list->items = NULL;
}
static void
pending_download_list_free(PendingDownloadList *list)
{
free(list->items);
}
static int
pending_download_list_add(PendingDownloadList *list, Address addr, SHA256 hash)
{
// Avoid duplicates
for (int i = 0; i < list->count; i++)
if (addr_eql(list->items[i].addr, addr) && !memcmp(&list->items[i].hash, &hash, sizeof(SHA256)))
return 0;
if (list->count == list->capacity) {
int new_capacity;
if (list->capacity == 0) new_capacity = 8;
else new_capacity = 2 * list->capacity;
PendingDownload *new_items = malloc(new_capacity * sizeof(PendingDownload));
if (new_items == NULL)
return -1;
if (list->capacity > 0) {
memcpy(new_items, list->items, list->count * sizeof(list->items[0]));
free(list->items);
}
list->items = new_items;
list->capacity = new_capacity;
}
list->items[list->count++] = (PendingDownload) { addr, hash };
return 0;
}
static int chunk_store_init(ChunkStore *store, string path)
{
if (create_dir(path) && errno != EEXIST)
return -1;
if (get_full_path(path, store->path) < 0)
return -1;
return 0;
}
static void chunk_store_free(ChunkStore *store)
{
(void) store;
}
static void append_hex_as_str(char *out, SHA256 hash)
{
char table[] = "0123456789abcdef";
for (int i = 0; i < (int) sizeof(hash); i++) {
out[(i << 1) + 0] = table[hash.data[i] >> 4];
out[(i << 1) + 1] = table[hash.data[i] & 0xF];
}
}
static string hash2path(ChunkStore *store, SHA256 hash, char *out)
{
strcpy(out, store->path);
strcat(out, "/");
size_t tmp = strlen(out);
append_hex_as_str(out + tmp, hash);
out[tmp + 64] = '\0';
return (string) { out, strlen(out) };
}
static int load_chunk(ChunkStore *store, SHA256 hash, string *data)
{
char buf[PATH_MAX];
string path = hash2path(store, hash, buf);
return file_read_all(path, data);
}
static int store_chunk(ChunkStore *store, string data, SHA256 *hash)
{
sha256(data.ptr, data.len, (uint8_t*) hash->data);
char buf[PATH_MAX];
string path = hash2path(store, *hash, buf);
return file_write_atomic(path, data);
}
static int chunk_store_get(ChunkStore *store, SHA256 hash, string *data)
{
return load_chunk(store, hash, data);
}
static int chunk_store_add(ChunkStore *store, string data)
{
SHA256 dummy;
return store_chunk(store, data, &dummy);
}
static void chunk_store_remove(ChunkStore *store, SHA256 hash)
{
char buf[PATH_MAX];
string path = hash2path(store, hash, buf);
remove_file_or_dir(path);
}
static int chunk_store_patch(ChunkStore *store, SHA256 target_chunk,
uint64_t patch_off, string patch, SHA256 *new_hash)
{
string data;
int ret = load_chunk(store, target_chunk, &data);
if (ret < 0)
return -1;
if (patch_off > SIZE_MAX - patch.len) {
free(data.ptr);
return -1;
}
if (patch_off + (size_t) patch.len > (size_t) data.len) {
free(data.ptr);
return -1;
}
memcpy(data.ptr + patch_off, patch.ptr, patch.len);
ret = store_chunk(store, data, new_hash);
if (ret < 0) {
free(data.ptr);
return -1;
}
free(data.ptr);
return 0;
}
static int send_error(TCP *tcp, int conn_idx,
bool close, uint16_t type, string msg)
{
MessageWriter writer;
ByteQueue *output = tcp_output_buffer(tcp, conn_idx);
message_writer_init(&writer, output, type);
uint16_t len = MIN(msg.len, UINT16_MAX);
message_write(&writer, &len, sizeof(len));
message_write(&writer, msg.ptr, len);
if (!message_writer_free(&writer))
return -1;
if (close)
return -1;
return 0;
}
static void start_download_if_necessary(ProgramState *state)
{
if (state->pending_download_list.count == 0 || state->downloading)
return;
ByteQueue *output;
if (tcp_connect(&state->tcp, state->pending_download_list.items[0].addr, TAG_CHUNK_SERVER, &output) < 0) {
// TODO
}
MessageWriter writer;
message_writer_init(&writer, output, xxx);
// TODO
if (!message_writer_free(&writer)) {
// TODO
}
}
static int
process_metadata_server_state_update(ProgramState *state, int conn_idx, ByteView msg)
{
uint32_t add_count;
uint32_t rem_count;
BinaryReader reader = { msg.ptr, msg.len, 0 };
// Read header
if (!binary_read(&reader, NULL, sizeof(MessageHeader)))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_STATE_UPDATE_ERROR, S("Invalid message"));
if (!binary_read(&reader, &add_count, sizeof(add_count)))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_STATE_UPDATE_ERROR, S("Invalid message"));
if (!binary_read(&reader, &rem_count, sizeof(rem_count)))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_STATE_UPDATE_ERROR, S("Invalid message"));
SHA256 *add_list = malloc(add_count * sizeof(SHA256));
SHA256 *rem_list = malloc(rem_count * sizeof(SHA256));
if (add_list == NULL || rem_list == NULL) {
free(add_list);
free(rem_list);
return send_error(&state->tcp, conn_idx, false, MESSAGE_TYPE_STATE_UPDATE_ERROR, S("Out of memory"));
}
for (uint32_t i = 0; i < add_count; i++) {
if (!binary_read(&reader, &add_list[i], sizeof(SHA256))) {
free(add_list);
free(rem_list);
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_STATE_UPDATE_ERROR, S("Invalid message"));
}
}
for (uint32_t i = 0; i < rem_count; i++) {
if (!binary_read(&reader, &rem_list[i], sizeof(SHA256))) {
free(add_list);
free(rem_list);
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_STATE_UPDATE_ERROR, S("Invalid message"));
}
}
if (binary_read(&reader, NULL, 1)) {
free(add_list);
free(rem_list);
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_STATE_UPDATE_ERROR, S("Invalid message"));
}
// TODO:
// - Move chunks in the remove list from the main directory to the orphaned directory
// - Check that chunks in the add list are either in the main directory or the orphaned
// directory. If they are in the orphaned directory, move them to the main directory.
// - If one or more chunks in the add list were not present in the main or orphaned
// directory, send an error to the metadata server with the list of missing chunks.
// If all chunks were present, send a success message.
free(add_list);
free(rem_list);
return 0;
}
static int
process_metadata_server_download_locations(ProgramState *state, int conn_idx, ByteView msg)
{
// The metadata server wants us to download chunks from other chunk servers
BinaryReader reader = { msg.ptr, msg.len, 0 };
// Read header
if (!binary_read(&reader, NULL, sizeof(MessageHeader)))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_XXX, S("Invalid message"));
// The message layout is this:
//
// struct IPv4Pair {
// IPv4 addr;
// uint16_t port;
// }
//
// struct IPv6Pair {
// IPv6 addr;
// uint16_t port;
// }
//
// struct AddressList {
// uint8_t num_ipv4;
// uint8_t num_ipv6;
// IPv4Pair ipv4[num_ipv4];
// IPv6Pair ipv6[num_ipv6];
// }
//
// struct Group {
// AddressList address_list;
// uint32_t num_hashes;
// SHA256 hashes[num_hashes];
// }
//
// struct Message {
// uint16_t num_groups;
// Group groups[num_groups]
// }
uint16_t num_groups;
if (binary_read(&reader, &num_groups, sizeof(num_groups)))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_XXX, S("Invalid message"));
for (uint16_t i = 0; i < num_groups; i++) {
uint8_t num_ipv4;
if (binary_read(&reader, &num_ipv4, sizeof(num_ipv4)))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_XXX, S("Invalid message"));
uint8_t num_ipv6;
if (binary_read(&reader, &num_ipv6, sizeof(num_ipv6)))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_XXX, S("Invalid message"));
IPv4 ipv4[UINT8_MAX];
IPv6 ipv6[UINT8_MAX];
uint8_t ipv4_port[UINT8_MAX];
uint16_t ipv6_port[UINT8_MAX];
for (uint8_t j = 0; j < num_ipv4; j++) {
if (binary_read(&reader, &ipv4[i], sizeof(ipv4[i])))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_XXX, S("Invalid message"));
if (binary_read(&reader, &ipv4_port[i], sizeof(ipv4_port[i])))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_XXX, S("Invalid message"));
}
for (uint8_t j = 0; j < num_ipv6; j++) {
if (binary_read(&reader, &ipv6[i], sizeof(ipv6[i])))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_XXX, S("Invalid message"));
if (binary_read(&reader, &ipv6_port[i], sizeof(ipv6_port[i])))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_XXX, S("Invalid message"));
}
uint32_t num_hashes;
if (binary_read(&reader, &num_hashes, sizeof(num_hashes)))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_XXX, S("Invalid message"));
for (uint32_t j = 0; j < num_hashes; j++) {
SHA256 hash;
if (binary_read(&reader, &hash, sizeof(hash)))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_XXX, S("Invalid message"));
for (uint8_t k = 0; k < num_ipv4; k++)
pending_download_list_add(
&state->pending_download_list,
(Address) { .is_ipv4=true, .ipv4=ipv4[k], .port=ipv4_port[i] },
hash
);
for (uint8_t k = 0; k < num_ipv6; k++)
pending_download_list_add(
&state->pending_download_list,
(Address) { .is_ipv4=false, .ipv6=ipv6[k], .port=ipv6_port[i] },
hash
);
}
}
if (binary_read(&reader, NULL, 1))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_XXX, S("Invalid message"));
start_download_if_necessary(state);
// There is no need to respond here
return 0;
}
static int
process_metadata_server_message(ProgramState *state, int conn_idx, uint16_t type, ByteView msg)
{
switch (type) {
case MESSAGE_TYPE_STATE_UPDATE:
return process_metadata_server_state_update(state, conn_idx, msg);
case MESSAGE_TYPE_DOWNLOAD_LOCATIONS:
return process_metadata_server_download_locations(state, conn_idx, msg);
}
return -1;
}
static int
process_chunk_server_download_error(ProgramState *state, int conn_idx, ByteView msg)
{
// TODO
}
static int
process_chunk_server_download_success(ProgramState *state, int conn_idx, ByteView msg)
{
// TODO
}
static int
process_chunk_server_message(ProgramState *state, int conn_idx, uint16_t msg_type, ByteView msg)
{
switch (msg_type) {
case MESSAGE_TYPE_DOWNLOAD_CHUNK_ERROR:
return process_chunk_server_download_error(state, conn_idx, msg);
case MESSAGE_TYPE_DOWNLOAD_CHUNK_SUCCESS:
return process_chunk_server_download_success(state, conn_idx, msg);
}
return -1;
}
static int
process_client_create_chunk(ProgramState *state, int conn_idx, ByteView msg)
{
BinaryReader reader = { msg.ptr, msg.len, 0 };
// Read header
if (!binary_read(&reader, NULL, sizeof(MessageHeader)))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_CREATE_CHUNK_ERROR, S("Invalid message"));
uint32_t chunk_size;
if (!binary_read(&reader, &chunk_size, sizeof(chunk_size)))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_CREATE_CHUNK_ERROR, S("Invalid message"));
uint32_t target_off;
if (!binary_read(&reader, &target_off, sizeof(target_off)))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_CREATE_CHUNK_ERROR, S("Invalid message"));
uint32_t target_len;
if (!binary_read(&reader, &target_len, sizeof(target_len)))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_CREATE_CHUNK_ERROR, S("Invalid message"));
string data = { reader.src + reader.cur, target_len };
if (!binary_read(&reader, NULL, target_len))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_CREATE_CHUNK_ERROR, S("Invalid message"));
// Check that there are no more bytes to read
if (binary_read(&reader, NULL, 1))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_CREATE_CHUNK_ERROR, S("Invalid message"));
char *mem = malloc(chunk_size);
if (mem == NULL)
return send_error(&state->tcp, conn_idx, false, MESSAGE_TYPE_CREATE_CHUNK_ERROR, S("Out of memory"));
assert(target_off + data.len <= chunk_size);
memset(mem, 0, chunk_size);
memcpy(mem + target_off, data.ptr, data.len);
SHA256 new_hash;
sha256(mem, chunk_size, (uint8_t*) new_hash.data);
int ret = chunk_store_add(&state->store, (string) { mem, chunk_size });
free(mem);
if (ret < 0)
return send_error(&state->tcp, conn_idx, false, MESSAGE_TYPE_CREATE_CHUNK_ERROR, S("I/O error"));
MessageWriter writer;
ByteQueue *output = tcp_output_buffer(&state->tcp, conn_idx);
message_writer_init(&writer, output, MESSAGE_TYPE_CREATE_CHUNK_SUCCESS);
message_write(&writer, &new_hash, sizeof(new_hash));
if (!message_writer_free(&writer))
return -1;
return 0;
}
static int
process_client_upload_chunk(ProgramState *state, int conn_idx, ByteView msg)
{
BinaryReader reader = { msg.ptr, msg.len, 0 };
// Read header
if (!binary_read(&reader, NULL, sizeof(MessageHeader)))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_UPLOAD_CHUNK_ERROR, S("Invalid message"));
SHA256 target_hash;
if (!binary_read(&reader, &target_hash, sizeof(target_hash)))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_UPLOAD_CHUNK_ERROR, S("Invalid message"));
uint32_t target_off;
if (!binary_read(&reader, &target_off, sizeof(target_off)))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_UPLOAD_CHUNK_ERROR, S("Invalid message"));
uint32_t data_len;
if (!binary_read(&reader, &data_len, sizeof(data_len)))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_UPLOAD_CHUNK_ERROR, S("Invalid message"));
string data = { reader.src + reader.cur, data_len };
// Check that there are no more bytes to read
if (binary_read(&reader, NULL, 1))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_UPLOAD_CHUNK_ERROR, S("Invalid message"));
SHA256 new_hash;
int ret = chunk_store_patch(&state->store, target_hash, target_off, data, &new_hash);
if (ret < 0)
return send_error(&state->tcp, conn_idx, false, MESSAGE_TYPE_UPLOAD_CHUNK_ERROR, S("I/O error"));
MessageWriter writer;
ByteQueue *output = tcp_output_buffer(&state->tcp, conn_idx);
message_writer_init(&writer, output, MESSAGE_TYPE_UPLOAD_CHUNK_SUCCESS);
if (!message_writer_free(&writer))
return -1;
return 0;
}
static int
process_client_download_chunk(ProgramState *state, int conn_idx, ByteView msg)
{
BinaryReader reader = { msg.ptr, msg.len, 0 };
// Read header
if (!binary_read(&reader, NULL, sizeof(MessageHeader)))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_DOWNLOAD_CHUNK_ERROR, S("Invalid message"));
SHA256 target_hash;
if (!binary_read(&reader, &target_hash, sizeof(target_hash)))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_DOWNLOAD_CHUNK_ERROR, S("Invalid message"));
uint32_t target_off;
if (!binary_read(&reader, &target_off, sizeof(target_off)))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_DOWNLOAD_CHUNK_ERROR, S("Invalid message"));
uint32_t target_len;
if (!binary_read(&reader, &target_len, sizeof(target_len)))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_DOWNLOAD_CHUNK_ERROR, S("Invalid message"));
// Check that there are no more bytes to read
if (binary_read(&reader, NULL, 1))
return send_error(&state->tcp, conn_idx, true, MESSAGE_TYPE_DOWNLOAD_CHUNK_ERROR, S("Invalid message"));
string data;
int ret = chunk_store_get(&state->store, target_hash, &data);
if (ret < 0)
return send_error(&state->tcp, conn_idx, false, MESSAGE_TYPE_DOWNLOAD_CHUNK_ERROR, S("I/O error"));
if (target_off >= (size_t) data.len || target_len > (size_t) data.len - target_off) {
free(data.ptr);
return send_error(&state->tcp, conn_idx, false, MESSAGE_TYPE_DOWNLOAD_CHUNK_ERROR, S("Invalid range"));
}
string slice = { data.ptr + target_off, target_len };
MessageWriter writer;
ByteQueue *output = tcp_output_buffer(&state->tcp, conn_idx);
message_writer_init(&writer, output, MESSAGE_TYPE_DOWNLOAD_CHUNK_SUCCESS);
message_write(&writer, &target_len, sizeof(target_len));
message_write(&writer, slice.ptr, slice.len);
free(data.ptr);
if (!message_writer_free(&writer))
return -1;
return 0;
}
static int
process_client_message(ProgramState *state, int conn_idx, uint16_t type, ByteView msg)
{
switch (type) {
case MESSAGE_TYPE_CREATE_CHUNK: return process_client_create_chunk(state, conn_idx, msg);
case MESSAGE_TYPE_UPLOAD_CHUNK: return process_client_upload_chunk(state, conn_idx, msg);
case MESSAGE_TYPE_DOWNLOAD_CHUNK: return process_client_download_chunk(state, conn_idx, msg);
default:break;
}
return -1;
}
int program_init(ProgramState *state, int argc, char **argv)
{
(void) argc;
(void) argv;
char addr[] = "127.0.0.1";
uint16_t port = 8080;
string path = S("chunk_server_data_0/");
char metadata_server_addr[] = "127.0.0.1";
uint16_t metadata_server_port = 8081;
tcp_context_init(&state->tcp);
int ret = tcp_listen(&state->tcp, addr, port);
if (ret < 0) {
tcp_context_free(&state->tcp);
return -1;
}
ret = chunk_store_init(&state->store, path);
if (ret < 0) {
tcp_context_free(&state->tcp);
return -1;
}
state->downloading = false;
pending_download_list_init(&state->pending_download_list);
// Initialize metadata server address
// // TODO: This should also support IPv6
state->metadata_server_addr.is_ipv4 = true;
if (inet_pton(AF_INET, metadata_server_addr, &state->metadata_server_addr.ipv4) != 1) {
tcp_context_free(&state->tcp);
chunk_store_free(&state->store);
return -1;
}
state->metadata_server_addr.port = metadata_server_port;
state->metadata_server_disconnect_time = 0;
return 0;
}
int program_free(ProgramState *state)
{
pending_download_list_free(&state->pending_download_list);
chunk_store_free(&state->store);
tcp_context_free(&state->tcp);
return 0;
}
int program_step(ProgramState *state)
{
Event events[MAX_CONNS+1];
int num_events = tcp_process_events(&state->tcp, events);
Time current_time = get_current_time();
if (current_time == INVALID_TIME)
return -1;
for (int i = 0; i < num_events; i++) {
int conn_idx = events[i].conn_idx;
switch (events[i].type) {
case EVENT_CONNECT:
if (tcp_get_tag(&state->tcp, conn_idx) == TAG_METADATA_SERVER)
state->metadata_server_disconnect_time = 0;
break;
case EVENT_DISCONNECT:
switch (tcp_get_tag(&state->tcp, conn_idx)) {
case TAG_METADATA_SERVER:
state->metadata_server_disconnect_time = current_time;
break;
case TAG_CHUNK_SERVER:
assert(state->downloading);
// TODO
break;
}
break;
case EVENT_MESSAGE:
{
ByteView msg;
uint16_t msg_type;
while (tcp_next_message(&state->tcp, conn_idx, &msg, &msg_type)) {
int ret;
switch (tcp_get_tag(&state->tcp, conn_idx)) {
case TAG_METADATA_SERVER:
ret = process_metadata_server_message(state, conn_idx, msg_type, msg);
break;
case TAG_CHUNK_SERVER:
ret = process_chunk_server_message(state, conn_idx, msg_type, msg);
break;
default:
ret = process_client_message(state, conn_idx, msg_type, msg);
break;
}
if (ret < 0) {
tcp_close(&state->tcp, conn_idx);
break;
}
tcp_consume_message(&state->tcp, conn_idx);
}
}
break;
}
}
// TODO: periodically look for chunks that have their hashes messed up and delete them
// TODO: periodically start downloads if some are pending and weren't started yet
// start_download_if_necessary(state);
if (state->metadata_server_disconnect_time > 0 && current_time - state->metadata_server_disconnect_time > CHUNK_SERVER_RECONNECT_TIME) {
ByteQueue *output;
if (tcp_connect(&state->tcp, state->metadata_server_addr, TAG_METADATA_SERVER, &output) < 0)
state->metadata_server_disconnect_time = current_time;
else {
state->metadata_server_disconnect_time = 0;
// TODO: need to send the AUTH message here
}
}
return 0;
}
#endif // BUILD_CHUNK_SERVER
//////////////////////////////////////////////////////////////////////////
// ENTRY POINT FOR METADATA AND CHUNK SERVER
//////////////////////////////////////////////////////////////////////////
#if defined(BUILD_METADATA_SERVER) || defined(BUILD_CHUNK_SERVER)
int main(int argc, char **argv)
{
int ret;
ProgramState state;
ret = program_init(&state, argc, argv);
if (ret < 0) return -1;
for (;;) {
ret = program_step(&state);
if (ret < 0) return -1;
}
return program_free(&state);
}
#endif
//////////////////////////////////////////////////////////////////////////
// CLIENT
//////////////////////////////////////////////////////////////////////////
#if !defined(BUILD_METADATA_SERVER) && !defined(BUILD_CHUNK_SERVER)
#include "TinyDFS.h"
#define MAX_OPERATIONS 128
#define MAX_REQUESTS_PER_QUEUE 128
typedef enum {
RESULT_TYPE_EMPTY,
RESULT_TYPE_CREATE_ERROR,
RESULT_TYPE_CREATE_SUCCESS,
RESULT_TYPE_DELETE_ERROR,
RESULT_TYPE_DELETE_SUCCESS,
RESULT_TYPE_LIST_ERROR,
RESULT_TYPE_LIST_SUCCESS,
RESULT_TYPE_READ_ERROR,
RESULT_TYPE_READ_SUCCESS,
RESULT_TYPE_WRITE_ERROR,
RESULT_TYPE_WRITE_SUCCESS,
} ResultType;
typedef struct {
ResultType type;
} Result;
typedef struct {
SHA256 hash;
char* dst;
uint32_t offset_within_chunk;
uint32_t length_within_chunk;
} Range;
typedef enum {
OPERATION_TYPE_FREE,
OPERATION_TYPE_CREATE,
OPERATION_TYPE_DELETE,
OPERATION_TYPE_LIST,
OPERATION_TYPE_READ,
OPERATION_TYPE_WRITE,
} OperationType;
typedef struct {
OperationType type;
void *ptr;
int len;
Range *ranges;
int ranges_head;
int ranges_count;
int num_pending;
Result result;
} Operation;
typedef struct {
int tag;
int operation_index;
} Request;
typedef struct {
int head;
int count;
Request items[MAX_REQUESTS_PER_QUEUE];
} RequestQueue;
typedef struct {
bool used;
Address addr;
RequestQueue reqs;
} MetadataServer;
typedef struct {
bool used;
Address addr;
RequestQueue reqs;
} ChunkServer;
typedef struct {
TCP tcp;
MetadataServer metadata_server;
int num_chunk_servers;
ChunkServer chunk_servers[MAX_CHUNK_SERVERS];
int num_operations;
Operation operations[MAX_OPERATIONS];
} Client;
static int client_init(Client *client)
{
tcp_context_init(&client->tcp);
if (tcp_connect(&client->tcp, addr, TAG_METADATA_SERVER) < 0) {
tcp_context_free(&client->tcp);
return -1;
}
client->num_operations = 0;
for (int i = 0; i < MAX_OPERATIONS; i++)
client->operations[i].type = OPERATION_TYPE_FREE;
return 0;
}
static void client_free(Client *client)
{
tcp_context_free(&client->tcp);
}
static int
alloc_operation(Client *client, OperationType type, void *ptr, int len)
{
if (client->num_operations == MAX_OPERATIONS)
return -1;
Operation *o = client->operations;
while (o->type != OPERATION_TYPE_FREE)
o++;
o->type = type;
o->ptr = ptr;
o->len = len;
o->result = (Result) { RESULT_TYPE_EMPTY };
client->num_operations++;
return o - client->operations;
}
static void free_operation(Client *client, int opidx)
{
client->operations[opidx].type = OPERATION_TYPE_FREE;
client->num_operations--;
}
static void
request_queue_init(RequestQueue *reqs)
{
reqs->head = 0;
reqs->count = 0;
}
static int
request_queue_push(RequestQueue *reqs, Request req)
{
if (reqs->count == MAX_REQUESTS_PER_QUEUE)
return -1;
int tail = (reqs->head + reqs->count) % MAX_REQUESTS_PER_QUEUE;
reqs->items[tail] = req;
reqs->count++;
return 0;
}
static int
request_queue_pop(RequestQueue *reqs, Request *req)
{
if (reqs->count == 0)
return -1;
if (req) *req = reqs->items[reqs->head];
reqs->head = (reqs->head + 1) % MAX_REQUESTS_PER_QUEUE;
reqs->count--;
return 0;
}
static void
metadata_server_request_start(Client *client, Writer *writer, uint16_t type)
{
int conn_idx = tcp_index_from_tag(&client->tcp, TAG_METADATA_SERVER);
ByteQueue *output = &tcp_output_buffer(&client->tcp, conn_idx);
message_writer_init(&writer, output, type);
}
static int
metadata_server_request_end(Client *client, Writer *writer, int opidx, int tag)
{
if (!message_writer_free(writer))
return -1;
RequestQueue *reqs = &client->metadata_server.reqs;
if (request_queue_push(reqs, (Request) { tag, opidx }) < 0)
return -1;
return 0;
}
static int
client_submit_create(Client *client, string path, bool is_dir, uint32_t chunk_size)
{
OperationType type = OPERATION_TYPE_CREATE;
int opidx = alloc_operation(client, type, NULL, 0);
if (opidx < 0) return -1;
Writer writer;
metadata_server_request_start(client, &writer, MESSAGE_TYPE_CREATE);
if (path.len > UINT16_MAX) {
free_operation(client, opidx);
return -1;
}
uint16_t path_len = path.len;
message_write(&writer, &path_len, sizeof(path_len));
message_write(&writer, path.ptr, path.len);
uint8_t tmp_u8 = is_dir;
message_write(&writer, &tmp_u8, sizeof(tmp_u8));
if (!is_dir) {
if (chunk_size == 0 || chunk_size > UINT32_MAX) {
free_operation(client, opidx);
return -1;
}
uint32_t tmp_u32 = chunk_size;
message_write(&writer, &tmp_u32, sizeof(tmp_u32));
}
if (metadata_server_request_end(client, &writer, opidx, 0) < 0) {
free_operation(client, opidx);
return -1;
}
return 0;
}
static int
client_submit_delete(Client *client, string path)
{
OperationType type = OPERATION_TYPE_DELETE;
int opidx = alloc_operation(client, type, NULL, 0);
if (opidx < 0) return -1;
Writer writer;
metadata_server_request_start(client, &writer, MESSAGE_TYPE_DELETE);
if (path.len > UINT16_MAX) {
free_operation(client, opidx);
return -1;
}
uint16_t path_len = path.len;
message_write(&writer, &path_len, sizeof(path_len));
message_write(&writer, path.ptr, path.len);
if (metadata_server_request_end(client, &writer, opidx, 0) < 0) {
free_operation(client, opidx);
return -1;
}
return 0;
}
static int
client_submit_list(Client *client, string path)
{
OperationType type = OPERATION_TYPE_LIST;
int opidx = alloc_operation(client, type, NULL, 0);
if (opidx < 0) return -1;
Writer writer;
metadata_server_request_start(client, &writer, MESSAGE_TYPE_LIST);
if (path.len > UINT16_MAX) {
free_operation(client, opidx);
return -1;
}
uint16_t path_len = path.len;
message_write(&writer, &path_len, sizeof(path_len));
message_write(&writer, path.ptr, path.len);
if (metadata_server_request_end(client, &writer, opidx, 0) < 0) {
free_operation(client, opidx);
return -1;
}
return 0;
}
static int send_read_message(Client *client, int opidx, int tag, string path, uint32_t offset, uint32_t length)
{
if (path.len > UINT16_MAX)
return -1;
uint16_t path_len = path.len;
Writer writer;
metadata_server_request_start(client, &writer, MESSAGE_TYPE_READ);
message_write(&writer, &path_len, sizeof(path_len));
message_write(&writer, path.ptr, path.len);
message_write(&writer, &offset, sizeof(offset));
message_write(&writer, &length, sizeof(length));
if (metadata_server_request_end(client, &writer, opidx, tag) < 0)
return -1;
return 0;
}
static int
client_submit_read(Client *client, string path, void *dst, int len)
{
OperationType type = OPERATION_TYPE_READ;
int opidx = alloc_operation(client, type, NULL, 0);
if (opidx < 0) return -1;
if (send_read_message(client, opidx, TAG_RETRIEVE_METADATA_FOR_READ, path, off, len) < 0) {
free_operation(client, opidx);
return -1;
}
return 0;
}
static int
client_submit_write(Client *client, string path, void *src, int len)
{
OperationType type = OPERATION_TYPE_WRITE;
int opidx = alloc_operation(client, type, NULL, 0);
if (opidx < 0) return -1;
if (send_read_message(client, opidx, TAG_RETRIEVE_METADATA_FOR_WRITE, path, off, len) < 0) {
free_operation(client, opidx);
return -1;
}
return 0;
}
static void process_event_for_create(Client *client,
int opidx, int request_tag, ByteView msg)
{
if (msg.len == 0) {
client->operations[opidx].result = (Result) { RESULT_TYPE_CREATE_ERROR };
return;
}
Reader reader = { msg.ptr, msg.len, 0 };
// version;
if (!binary_read(&reader, NULL, sizeof(uint16_t))) {
client->operations[opidx].result = (Result) { RESULT_TYPE_CREATE_ERROR };
return;
}
uint16_t type;
if (!binary_read(&reader, &type, sizeof(type))) {
client->operations[opidx].result = (Result) { RESULT_TYPE_CREATE_ERROR };
return;
}
// length
if (!binary_read(&reader, NULL, sizeof(uint32_t))) {
client->operations[opidx].result = (Result) { RESULT_TYPE_CREATE_ERROR };
return;
}
if (type != MESSAGE_TYPE_CREATE_SUCCESS) {
client->operations[opidx].result = (Result) { RESULT_TYPE_CREATE_ERROR };
return;
}
// Check there is nothing else to read
if (binary_read(&reader, NULL, 1)) {
client->operations[opidx].result = (Result) { RESULT_TYPE_CREATE_ERROR };
return;
}
client->operations[opidx].result = (Result) { RESULT_TYPE_CREATE_SUCCESS };
}
static void process_event_for_delete(Client *client,
int opidx, int request_tag, ByteView msg)
{
if (msg.len == 0) {
client->operations[opidx].result = (Result) { RESULT_TYPE_DELETE_ERROR };
return;
}
Reader reader = { msg.ptr, msg.len, 0 };
// version
if (!binary_read(&reader, NULL, sizeof(uint16_t))) {
client->operations[opidx].result = (Result) { RESULT_TYPE_DELETE_ERROR };
return;
}
uint16_t type;
if (!binary_read(&reader, &type, sizeof(type))) {
client->operations[opidx].result = (Result) { RESULT_TYPE_DELETE_ERROR };
return;
}
// length
if (!binary_read(&reader, NULL, sizeof(uint32_t))) {
client->operations[opidx].result = (Result) { RESULT_TYPE_DELETE_ERROR };
return;
}
if (type != MESSAGE_TYPE_DELETE_SUCCESS) {
client->operations[opidx].result = (Result) { RESULT_TYPE_DELETE_ERROR };
return;
}
// Check there is nothing else to read
if (binary_read(&reader, NULL, 1)) {
client->operations[opidx].result = (Result) { RESULT_TYPE_DELETE_ERROR };
return;
}
client->operations[opidx].result = (Result) { RESULT_TYPE_DELETE_SUCCESS };
}
static void process_event_for_list(Client *client,
int opidx, int request_tag, ByteView msg)
{
if (msg.len == 0) {
client->operations[opidx].result = (Result) { RESULT_TYPE_LIST_ERROR };
return;
}
Reader reader = { msg.ptr, msg.len, 0 };
// version
if (!binary_read(&reader, NULL, sizeof(uint16_t))) {
client->operations[opidx].result = (Result) { RESULT_TYPE_LIST_ERROR };
return;
}
uint16_t type;
if (!binary_read(&reader, &type, sizeof(type))) {
client->operations[opidx].result = (Result) { RESULT_TYPE_LIST_ERROR };
return;
}
// length
if (!binary_read(&reader, NULL, sizeof(uint32_t))) {
client->operations[opidx].result = (Result) { RESULT_TYPE_LIST_ERROR };
return;
}
if (type != MESSAGE_TYPE_LIST_SUCCESS) {
client->operations[opidx].result = (Result) { RESULT_TYPE_LIST_ERROR };
return;
}
// TODO: read list
// Check there is nothing else to read
if (binary_read(&reader, NULL, 1)) {
client->operations[opidx].result = (Result) { RESULT_TYPE_LIST_ERROR };
return;
}
client->operations[opidx].result = (Result) { RESULT_TYPE_LIST_SUCCESS };
}
static void process_event_for_read(Client *client,
int opidx, int request_tag, ByteView msg)
{
if (msg.len == 0) {
client->operations[opidx].result = (Result) { RESULT_TYPE_READ_ERROR };
return;
}
switch (request_tag) {
case TAG_RETRIEVE_METADATA_FOR_READ:
{
Reader reader = { msg.ptr, msg.len, 0 };
// version
if (!binary_read(&reader, NULL, sizeof(uint16_t))) {
client->operations[opidx].result = (Result) { RESULT_TYPE_READ_ERROR };
return;
}
uint16_t type;
if (!binary_read(&reader, &type, sizeof(type))) {
client->operations[opidx].result = (Result) { RESULT_TYPE_READ_ERROR };
return;
}
if (type != MESSAGE_TYPE_READ_SUCCESS) {
// TODO
}
// length
if (!binary_read(&reader, NULL, sizeof(uint32_t))) {
client->operations[opidx].result = (Result) { RESULT_TYPE_READ_ERROR };
return;
}
uint32_t chunk_size;
if (!binary_read(&reader, &chunk_size, sizeof(chunk_size))) {
client->operations[opidx].result = (Result) { RESULT_TYPE_READ_ERROR };
return;
}
uint32_t first_byte = off;
uint32_t last_byte = off + len - 1; // TODO: what if len=0 ?
uint32_t first_chunk = first_byte / chunk_size;
uint32_t last_chunk = last_byte / chunk_size;
uint32_t num_chunks = 1 + last_chunk - first_chunk;
uint32_t num_hashes;
if (!binary_read(&writer, &num_hashes, sizeof(num_hashes))) {
// TODO
}
Range *ranges = malloc(num_hashes * sizeof(Range));
if (ranges == NULL) {
client->operations[opidx].result = (Result) { RESULT_TYPE_READ_ERROR };
return;
}
char *ptr = client->operations[opidx].ptr;
for (uint32_t i = first_chunk; i <= last_chunk; i++) {
uint32_t first_byte_within_chunk = 0;
uint32_t last_byte_within_chunk = chunk_size-1; // TODO: what if chunk size is 0 ?
if (i == first_chunk) first_byte_within_chunk = first_byte % chunk_size;
if (i == last_chunk) last_byte_within_chunk = last_byte % chunk_size;
uint32_t length_within_chunk = 1 + last_byte_within_chunk - first_byte_within_chunk;
if (i - first_chunk < num_hashes) {
SHA256 hash;
if (!binary_read(&writer, &hash, sizeof(hash))) {
// TODO
}
ranges[i - first_chunk] = (Range) {
.hash = hash,
.dst = ptr,
.offset_within_chunk = offset_within_chunk,
.length_within_chunk = length_within_chunk,
};
} else {
memset(ptr, 0, length_within_chunk);
}
ptr += length_within_chunk;
}
// Check there is nothing else to read
if (binary_read(&reader, NULL, 1)) {
client->operations[opidx].result = (Result) { RESULT_TYPE_LIST_ERROR };
return;
}
client->operations[opidx].ranges = ranges;
client->operations[opidx].ranges_head = 0;
client->operations[opidx].ranges_count = num_hashes;
client->operations[opidx].num_pending = 0;
// TODO: start N downloads
}
break;
default:
{
Reader reader = { msg.ptr, msg.len, 0 };
// version
if (!binary_read(&reader, NULL, sizeof(uint16_t))) {
client->operations[opidx].result = (Result) { RESULT_TYPE_READ_ERROR };
return;
}
uint16_t type;
if (!binary_read(&reader, &type, sizeof(type))) {
client->operations[opidx].result = (Result) { RESULT_TYPE_READ_ERROR };
return;
}
if (type != MESSAGE_TYPE_DOWNLOAD_CHUNK_SUCCESS) {
// TODO
}
// length
if (!binary_read(&reader, NULL, sizeof(uint32_t))) {
client->operations[opidx].result = (Result) { RESULT_TYPE_READ_ERROR };
return;
}
// TODO
// Check there is nothing else to read
if (binary_read(&reader, NULL, 1)) {
client->operations[opidx].result = (Result) { RESULT_TYPE_LIST_ERROR };
return;
}
memcpy(client->operations[opidx].ranges[request_tag].dst, xxx, yyy);
client->operations[opidx].num_pending--;
if (client->operations[opidx].num_pending == 0) {
client->operations[opidx].result = (Result) { RESULT_TYPE_READ_SUCCESS };
} else {
// TODO: start operation
}
}
break;
}
}
static void process_event_for_write(Client *client,
int opidx, int request_tag, ByteView msg)
{
if (msg.len == 0) {
client->operations[opidx].result = (Result) { RESULT_TYPE_WRITE_ERROR };
return;
}
switch (request_tag) {
case TAG_RETRIEVE_METADATA_FOR_WRITE:
break;
}
// TODO
}
static void process_event(Client *client,
int opidx, int request_tag, ByteView msg)
{
switch (client->operations[opidx].type) {
case OPERATION_TYPE_CREATE: process_event_for_create(client, opidx, request_tag, msg); break;
case OPERATION_TYPE_DELETE: process_event_for_delete(client, opidx, request_tag, msg); break;
case OPERATION_TYPE_LIST : process_event_for_list (client, opidx, request_tag, msg); break;
case OPERATION_TYPE_READ : process_event_for_read (client, opidx, request_tag, msg); break;
case OPERATION_TYPE_WRITE : process_event_for_write (client, opidx, request_tag, msg); break;
default: UNREACHABLE;
}
}
static bool
translate_operation_into_result(Client *client, int opidx, Result *result)
{
if (client->operations[opidx].result.type == RESULT_TYPE_EMPTY)
return false;
*result = client->operations[opidx].result;
client->operations[opidx].type = OPERATION_TYPE_FREE;
client->num_operations--;
return true;
}
static void client_wait(Client *client, int opidx, Result *result, int timeout)
{
for (;;) {
if (opidx < 0) {
for (int i = 0, j = 0; j < client->num_operations; i++) {
if (client->operations[i].type == OPERATION_TYPE_FREE)
continue;
j++;
if (translate_operation_into_result(client, i, result))
return;
}
} else {
if (translate_operation_into_result(client, opidx, result))
return;
}
int num_events;
Event events[MAX_CONNS+1];
num_events = tcp_process_events(&client->tcp, events);
for (int i = 0; i < num_events; i++) {
int conn_idx = events[i].conn_idx;
switch (events[i].type) {
case EVENT_CONNECT:
break;
case EVENT_DISCONNECT:
{
RequestQueue *reqs;
int tag = tcp_get_tag(&client->tcp, conn_idx);
if (tag == TAG_METADATA_SERVER_TO_CLIENT)
reqs = &client->metadata_server.reqs;
else {
assert(tag > -1);
reqs = &client->chunk_servers[tag].reqs;
}
for (Request req; request_queue_pop(reqs, &req) == 0; )
process_event(client, req.opidx, (ByteView) { NULL, 0 });
}
break;
case EVENT_MESSAGE:
{
RequestQueue *reqs;
int tag = tcp_get_tag(&client->tcp, conn_idx);
if (tag == TAG_METADATA_SERVER_TO_CLIENT)
reqs = &client->metadata_server.reqs;
else {
assert(tag > -1);
reqs = &client->chunk_servers[tag].reqs;
}
Request req;
if (request_queue_pop(reqs, &req) < 0) {
UNREACHABLE;
}
process_event(client, req.opidx, req.tag, events[i].msg);
}
break;
}
}
}
}
struct TinyDFS {
Client client;
};
TinyDFS *tinydfs_init(void)
{
TinyDFS *tdfs = malloc(sizeof(TinyDFS));
if (tdfs == NULL)
return NULL;
if (client_init(&tdfs->client) < 0) {
free(tdfs);
return NULL;
}
return tdfs;
}
void tinydfs_free(TinyDFS *tdfs)
{
client_free(&tdfs->client);
free(tdfs);
}
int tinydfs_wait(TinyDFS *tdfs, TinyDFS_Handle handle,
TinyDFS_Result *result, int timeout)
{
// TODO
}
TinyDFS_Handle tinydfs_submit_create(TinyDFS *tdfs,
char *path, int path_len, bool is_dir, unsigned int chunk_size)
{
// TODO
}
TinyDFS_Handle tinydfs_submit_delete(TinyDFS *tdfs,
char *path, int path_len)
{
// TODO
}
TinyDFS_Handle tinydfs_submit_list(TinyDFS *tdfs,
char *path, int path_len)
{
// TODO
}
TinyDFS_Handle tinydfs_submit_read(TinyDFS *tdfs,
char *path, int path_len, void *dst, int len)
{
// TODO
}
TinyDFS_Handle tinydfs_submit_write(TinyDFS *tdfs,
char *path, int path_len, void *src, int len)
{
// TODO
}
#endif
//////////////////////////////////////////////////////////////////////////
// THE END
//////////////////////////////////////////////////////////////////////////
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