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9948716be851e87b7efd9277603bc2fd06159d55
ToastyFS/src/file_tree.c
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Claude 9948716be8 Fix assertion failure in file_tree_read when read operation fails 
Initialize *gen to NO_GENERATION at the start of file_tree_read so that
error paths (FILETREE_BADPATH, FILETREE_NOENT, FILETREE_ISDIR) have a
well-defined value. Previously, when file_tree_read failed, gen was
uninitialized, causing the assertion in process_client_read to fire.

The assertion checking gen != NO_GENERATION before the error check was
removed since:
1. On error paths, gen is not used
2. On success paths, the assertion at line 482 already validates gen
2026-01-16 18:48:23 +00:00

821 lines
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#ifdef MAIN_SIMULATION
#define QUAKEY_ENABLE_MOCKS
#endif
#include <stdint.h>
#include <assert.h>
#include <quakey.h>
#include "basic.h"
#include "file_tree.h"
static int parse_path(string path, string *comps, int max)
{
bool is_absolute = false;
if (path.len > 0 && path.ptr[0] == '/') {
is_absolute = true;
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) {
// For absolute paths, ".." at root is ignored (stays at root)
// For relative paths, ".." with no components references parent, which is invalid
if (!is_absolute)
return -1;
// Otherwise, ignore the ".." (absolute path, already at root)
} else {
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 bool gen_match(uint64_t expected_gen, uint64_t entity_gen)
{
assert(entity_gen != NO_GENERATION);
assert(entity_gen != MISSING_FILE_GENERATION);
// NO_GENERATION means "skip generation check"
if (expected_gen == NO_GENERATION)
return true;
// MISSING_FILE_GENERATION means "expect file to NOT exist"
// Since we're checking against an existing entity, this is a mismatch
if (expected_gen == MISSING_FILE_GENERATION)
return false;
return expected_gen == entity_gen;
}
static uint64_t create_generation(uint64_t *next_gen)
{
(*next_gen)++;
if (*next_gen == 0 || *next_gen == UINT64_MAX)
*next_gen = 1;
return *next_gen;
}
static int dir_remove(Dir *d, int idx, uint64_t expected_gen)
{
if (!gen_match(expected_gen, d->children[idx].gen))
return -1;
// TODO: pretty sure this leaks memory
d->children[idx] = d->children[--d->num_children];
return 0;
}
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->file_size = 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, uint64_t *next_gen)
{
if (name_len >= (int) sizeof(e->name))
return -1;
e->gen = create_generation(next_gen);
assert(e->gen != NO_GENERATION);
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);
}
int file_tree_init(FileTree *ft)
{
ft->next_gen = 1;
int ret = entity_init(&ft->root, "", 0, true, 0, &ft->next_gen);
if (ret < 0) return -1;
return 0;
}
void file_tree_free(FileTree *ft)
{
entity_free(&ft->root);
}
bool file_tree_uses_hash(FileTree *ft, SHA256 hash)
{
return entity_uses_hash(&ft->root, hash);
}
int file_tree_list(FileTree *ft, string path,
ListItem *items, int max_items, uint64_t *gen)
{
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;
items[i].gen = c->gen;
}
assert(e->gen != NO_GENERATION);
*gen = e->gen;
return d->num_children;
}
int file_tree_create_entity(FileTree *ft, string path,
bool is_dir, uint64_t chunk_size, uint64_t *gen)
{
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, &ft->next_gen);
if (ret < 0)
// Invalid name for the new file
return FILETREE_BADPATH;
assert(e->gen != NO_GENERATION);
*gen = e->gen;
d->num_children++;
return 0;
}
// TODO: this should return the list of unreferenced hashes
int file_tree_delete_entity(FileTree *ft, string path,
uint64_t expected_gen)
{
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) {
// File doesn't exist
// If caller expected it not to exist (MISSING_FILE_GENERATION), succeed
if (expected_gen == MISSING_FILE_GENERATION)
return 0;
return FILETREE_NOENT;
}
// File exists - check generation
if (dir_remove(&e->d, i, expected_gen) < 0)
return FILETREE_BADGEN;
return 0;
}
int file_tree_write(
FileTree* ft,
string path,
uint64_t off,
uint64_t len,
uint32_t num_chunks,
uint64_t expect_gen,
uint64_t* new_gen,
SHA256* hashes,
SHA256* removed_hashes,
int* num_removed,
bool truncate_after)
{
// WRITE operations cannot use expect_gen=0
if (expect_gen == NO_GENERATION)
return FILETREE_BADGEN;
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) {
// File doesn't exist
// If caller expected it not to exist (MISSING_FILE_GENERATION), that's correct
// but we still can't write to a non-existent file (need CREATE_IF_MISSING flag in client layer)
if (expect_gen == MISSING_FILE_GENERATION)
return FILETREE_NOENT; // Expected behavior: file missing as expected, but can't write
return FILETREE_NOENT;
}
if (e->is_dir)
return FILETREE_ISDIR;
// Check generation - will fail if expect_gen is MISSING_FILE_GENERATION (expects missing but file exists)
if (!gen_match(expect_gen, e->gen))
return FILETREE_BADGEN;
File *f = &e->f;
uint64_t first_chunk_index = off / f->chunk_size;
uint64_t last_chunk_index = first_chunk_index + (len - 1) / f->chunk_size;
assert(last_chunk_index - first_chunk_index + 1 == num_chunks);
if (last_chunk_index >= f->num_chunks) {
uint64_t old_num_chunks = f->num_chunks;
SHA256 *new_chunks = malloc((last_chunk_index+1) * sizeof(SHA256));
if (new_chunks == NULL)
return FILETREE_NOMEM;
if (f->chunks) {
if (f->num_chunks > 0)
memcpy(new_chunks, f->chunks, f->num_chunks * sizeof(SHA256));
free(f->chunks);
}
f->chunks = new_chunks;
f->num_chunks = last_chunk_index+1;
for (uint64_t i = old_num_chunks; i < last_chunk_index+1; i++)
memset(&f->chunks[i], 0, sizeof(SHA256));
}
int num_overwritten_hashes = 0;
SHA256 overwritten_hashes[100]; // TODO: fix this limit
if (num_chunks > 100) {
assert(0); // TODO
}
// Update chunks
for (uint64_t i = first_chunk_index; i <= last_chunk_index; i++) {
overwritten_hashes[num_overwritten_hashes++] = f->chunks[i];
f->chunks[i] = hashes[i - first_chunk_index];
}
// Update file size (last byte written + 1)
uint64_t new_size = off + len;
if (truncate_after) {
// With truncation, set file size to exactly new_size and remove chunks beyond
uint64_t new_num_chunks = last_chunk_index + 1;
// Add any chunks beyond the write to the overwritten list (they'll be removed)
for (uint64_t i = new_num_chunks; i < f->num_chunks; i++) {
if (num_overwritten_hashes < 100) { // Respect the limit
overwritten_hashes[num_overwritten_hashes++] = f->chunks[i];
}
}
f->num_chunks = new_num_chunks;
f->file_size = new_size;
} else {
// Without truncation, only grow the file
if (new_size > f->file_size)
f->file_size = new_size;
}
// Now check which old hashes are no longer used
// anywhere in the tree
//
// NOTE: If removed_hashes is NULL, the caller isn't
// interested in which hashes are no longer reachable.
if (removed_hashes != NULL) {
*num_removed = 0;
for (int i = 0; i < num_overwritten_hashes; i++) {
SHA256 hash = overwritten_hashes[i];
// Skip zero hashes
bool is_zero = true;
for (int j = 0; j < (int) sizeof(SHA256); j++) {
if (hash.data[j] != 0) {
is_zero = false;
break;
}
}
if (is_zero)
continue;
// Check if this hash is still used anywhere in the tree
if (!entity_uses_hash(&ft->root, hash)) {
removed_hashes[*num_removed] = hash;
(*num_removed)++;
}
}
}
e->gen = create_generation(&ft->next_gen);
assert(e->gen != NO_GENERATION);
*new_gen = e->gen;
return 0;
}
int file_tree_read(FileTree *ft, string path,
uint64_t off, uint64_t len, uint64_t *gen, uint64_t *chunk_size,
SHA256 *hashes, int max_hashes, uint64_t *actual_bytes)
{
// Initialize gen to NO_GENERATION so error paths have a well-defined value
*gen = NO_GENERATION;
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_ISDIR;
File *f = &e->f;
*chunk_size = f->chunk_size;
// Calculate actual bytes that can be read based on actual file size
if (off >= f->file_size) {
*actual_bytes = 0;
} else if (off + len > f->file_size) {
*actual_bytes = f->file_size - off;
} else {
*actual_bytes = len;
}
if (len == 0) {
assert(e->gen != NO_GENERATION);
*gen = e->gen;
return 0;
}
uint64_t first_chunk_index = off / f->chunk_size;
uint64_t last_chunk_index = first_chunk_index + (len - 1) / f->chunk_size;
if (first_chunk_index >= f->num_chunks) {
*gen = e->gen;
return 0;
}
if (last_chunk_index >= f->num_chunks) {
if (f->num_chunks == 0) {
assert(e->gen != NO_GENERATION);
*gen = e->gen;
return 0;
}
last_chunk_index = f->num_chunks-1;
}
int num_hashes = 0;
for (uint32_t i = first_chunk_index; i <= last_chunk_index; i++) {
SHA256 hash = f->chunks[i];
if (num_hashes < max_hashes)
hashes[num_hashes] = hash;
num_hashes++;
}
assert(e->gen != NO_GENERATION);
*gen = e->gen;
return num_hashes;
}
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");
case FILETREE_BADGEN : return S("Generation counter mismatch or invalid value");
default:break;
}
return S("Unknown error");
}
typedef struct {
int (*write_fn)(char*,int,void*);
void *write_data;
char *buffer;
int buffer_size;
int buffer_used;
bool error;
} SerializeContext;
static void sc_flush(SerializeContext *sc)
{
if (sc->error)
return;
int ret = sc->write_fn(sc->buffer, sc->buffer_used, sc->write_data);
if (ret < 0) {
sc->error = true;
return;
}
sc->buffer_used = 0;
}
static void sc_write_mem(SerializeContext *sc, char *src, int len)
{
if (sc->error)
return;
if (sc->buffer_size - sc->buffer_used < len) {
if (len > sc->buffer_size) {
sc->error = true;
return;
}
sc_flush(sc);
if (sc->error)
return;
}
memcpy(sc->buffer + sc->buffer_used, src, len);
sc->buffer_used += len;
}
static void sc_write_u8 (SerializeContext *sc, uint8_t value) { sc_write_mem(sc, (char*) &value, (int) sizeof(value)); }
static void sc_write_u16 (SerializeContext *sc, uint16_t value) { sc_write_mem(sc, (char*) &value, (int) sizeof(value)); }
static void sc_write_u64 (SerializeContext *sc, uint64_t value) { sc_write_mem(sc, (char*) &value, (int) sizeof(value)); }
static void sc_write_hash(SerializeContext *sc, SHA256 value) { sc_write_mem(sc, (char*) &value, (int) sizeof(value)); }
static void file_serialize(SerializeContext *sc, File *f)
{
sc_write_u64(sc, f->chunk_size);
sc_write_u64(sc, f->num_chunks);
sc_write_u64(sc, f->file_size);
for (uint64_t i = 0; i < f->num_chunks; i++)
sc_write_hash(sc, f->chunks[i]);
}
static void entity_serialize(SerializeContext *sc, Entity *e);
static void dir_serialize(SerializeContext *sc, Dir *d)
{
sc_write_u64(sc, d->num_children);
for (uint64_t i = 0; i < d->num_children; i++)
entity_serialize(sc, &d->children[i]);
}
static void entity_serialize(SerializeContext *sc, Entity *e)
{
sc_write_u16(sc, e->name_len);
sc_write_mem(sc, e->name, e->name_len);
sc_write_u8(sc, e->is_dir);
if (e->is_dir)
dir_serialize(sc, &e->d);
else
file_serialize(sc, &e->f);
}
int file_tree_serialize(FileTree *ft, int (*write_fn)(char*,int,void*), void *write_data)
{
SerializeContext sc;
sc.write_fn = write_fn;
sc.write_data = write_data;
sc.buffer_used = 0;
sc.buffer_size = 1<<10;
sc.buffer = malloc(sc.buffer_size);
sc.error = false;
if (sc.buffer == NULL)
sc.error = true;
entity_serialize(&sc, &ft->root);
sc_flush(&sc);
free(sc.buffer);
if (sc.error)
return -1;
return 0;
}
typedef struct {
int (*read_fn)(char*,int,void*);
void *read_data;
char *buffer;
int buffer_size;
int buffer_used;
int buffer_head;
bool error;
uint64_t total_read;
} DeserializeContext;
static void dc_read_mem(DeserializeContext *dc, void *dst, int len)
{
if (dc->error)
return;
if (dc->buffer_used < len) {
if (dc->buffer_size < len) {
dc->error = true;
return;
}
memmove(dc->buffer, dc->buffer + dc->buffer_head, dc->buffer_used);
dc->buffer_head = 0;
int ret = dc->read_fn(
dc->buffer + dc->buffer_used,
dc->buffer_size - dc->buffer_used,
dc->read_data);
if (ret < 0) {
dc->error = true;
return;
}
dc->buffer_used += ret;
if (dc->buffer_used < len) {
dc->error = true;
return;
}
}
memcpy(dst, dc->buffer + dc->buffer_head, len);
dc->buffer_head += len;
dc->buffer_used -= len;
dc->total_read += len;
}
static void dc_read_u8 (DeserializeContext *dc, uint8_t *dst) { dc_read_mem(dc, dst, sizeof(*dst)); }
static void dc_read_u16(DeserializeContext *dc, uint16_t *dst) { dc_read_mem(dc, dst, sizeof(*dst)); }
static void dc_read_u64(DeserializeContext *dc, uint64_t *dst) { dc_read_mem(dc, dst, sizeof(*dst)); }
static void dc_read_hash(DeserializeContext *dc, SHA256 *dst) { dc_read_mem(dc, dst, sizeof(*dst)); }
static void file_deserialize(DeserializeContext *dc, File *f)
{
dc_read_u64(dc, &f->chunk_size);
dc_read_u64(dc, &f->num_chunks);
dc_read_u64(dc, &f->file_size);
f->chunks = malloc(f->num_chunks * sizeof(SHA256));
if (f->chunks == NULL) {
assert(0); // TODO
}
for (uint64_t i = 0; i < f->num_chunks; i++)
dc_read_hash(dc, &f->chunks[i]);
}
static void entity_deserialize(DeserializeContext *dc, Entity *e);
static void dir_deserialize(DeserializeContext *dc, Dir *d)
{
dc_read_u64(dc, &d->num_children);
d->max_children = d->num_children;
d->children = malloc(d->num_children * sizeof(Entity));
if (d->children == NULL) {
assert(0); // TODO
}
// TODO: not checking for errors is not okay as
// the code will branch based on garbage
// values.
for (uint64_t i = 0; i < d->num_children; i++)
entity_deserialize(dc, &d->children[i]);
}
static void entity_deserialize(DeserializeContext *dc, Entity *e)
{
dc_read_u16(dc, &e->name_len); // TODO: make sure this doesn't go over the static buffer
dc_read_mem(dc, e->name, e->name_len);
uint8_t is_dir;
dc_read_u8 (dc, &is_dir);
e->is_dir = (is_dir != 0);
if (e->is_dir)
dir_deserialize(dc, &e->d);
else
file_deserialize(dc, &e->f);
}
int file_tree_deserialize(FileTree *ft, int (*read_fn)(char*,int,void*), void *read_data)
{
DeserializeContext dc;
dc.read_fn = read_fn;
dc.read_data = read_data;
dc.buffer_head = 0;
dc.buffer_used = 0;
dc.buffer_size = 1<<10;
dc.buffer = malloc(dc.buffer_size);
dc.error = false;
if (dc.buffer == NULL)
dc.error = true;
dc.total_read = 0;
entity_deserialize(&dc, &ft->root);
free(dc.buffer);
if (dc.error)
return -1;
if (dc.total_read > INT_MAX) {
assert(0); // TODO
}
return dc.total_read;
}
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