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fix(linux): prevent segfaults during rapid module reloads

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Fixes multiple issues causing segfaults when hot-reloading modules
on Linux, particularly when file changes are detected rapidly:

- Enable is_file_ready() check on Linux to prevent loading partially-written
  shared libraries (previously only used on Windows/BSD)
- Fix event deduplication on Linux to actually remove duplicate inotify events
  instead of just marking them, preventing double-free on same module
- Reorder reload operations to unload old module only after successfully
  copying new version, avoiding invalid state when copy fails

Changes:
- platform.c: Remove __linux__ guards around is_file_ready() function
- platform.c: Add compaction step after deduplication to remove -1 entries
- stk.c: Move module unload to after platform_copy_file() in reload loop

These changes make Linux hot-reload as robust as Windows/BSD implementations.
This commit is contained in:
anth64
2026-02-09 22:25:02 +01:00
parent 043fea6092
commit f83f2051ef
2 changed files with 114 additions and 103 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/platform.c
+112 -100
View File
@@ -32,7 +32,6 @@ int is_mod_loaded(const char *module_name);
uint8_t is_valid_module_file(const char *filename); uint8_t is_valid_module_file(const char *filename);
void extract_module_id(const char *path, char *out_id); void extract_module_id(const char *path, char *out_id);
#ifndef __linux__
static uint8_t is_file_ready(const char *dir_path, const char *filename) static uint8_t is_file_ready(const char *dir_path, const char *filename)
{ {
char full_path[STK_PATH_MAX_OS]; char full_path[STK_PATH_MAX_OS];
@@ -80,6 +79,7 @@ static uint8_t is_file_ready(const char *dir_path, const char *filename)
#endif #endif
} }
#ifndef __linux__
typedef struct { typedef struct {
char filename[STK_PATH_MAX]; char filename[STK_PATH_MAX];
#ifdef _WIN32 #ifdef _WIN32
@@ -146,7 +146,6 @@ uint8_t platform_copy_file(const char *from, const char *to)
FILE *src = NULL, *dst = NULL; FILE *src = NULL, *dst = NULL;
char tmp_path[STK_PATH_MAX_OS]; char tmp_path[STK_PATH_MAX_OS];
size_t n; size_t n;
#ifndef __linux__
char dir_path[STK_PATH_MAX_OS]; char dir_path[STK_PATH_MAX_OS];
const char *filename; const char *filename;
@@ -163,7 +162,6 @@ uint8_t platform_copy_file(const char *from, const char *to)
if (!is_file_ready(dir_path, filename)) if (!is_file_ready(dir_path, filename))
goto done; goto done;
#endif
sprintf(tmp_path, "%s.tmp", to); sprintf(tmp_path, "%s.tmp", to);
@@ -286,128 +284,127 @@ void *platform_get_symbol(void *h, const char *s)
#endif #endif
} }
char (*platform_directory_init_scan(const char *dir_path, char (*platform_directory_init_scan(const char *dir_path, size_t *out_count))
size_t *out_count))[STK_PATH_MAX] [STK_PATH_MAX] {
{ size_t count = 0, i = 0, name_len;
size_t count = 0, i = 0, name_len; char (*list)[STK_PATH_MAX] = NULL;
char(*list)[STK_PATH_MAX] = NULL;
#ifdef _WIN32 #ifdef _WIN32
WIN32_FIND_DATAA fd; WIN32_FIND_DATAA fd;
HANDLE h; HANDLE h;
char s[STK_PATH_MAX_OS]; char s[STK_PATH_MAX_OS];
sprintf(s, "%s\\*", dir_path); sprintf(s, "%s\\*", dir_path);
h = FindFirstFileA(s, &fd); h = FindFirstFileA(s, &fd);
if (h == INVALID_HANDLE_VALUE) if (h == INVALID_HANDLE_VALUE)
goto create_and_exit; goto create_and_exit;
do { do {
if ((fd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)) if ((fd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY))
continue; continue;
if (is_valid_module_file(fd.cFileName)) if (is_valid_module_file(fd.cFileName))
count++; count++;
} while (FindNextFileA(h, &fd)); } while (FindNextFileA(h, &fd));
FindClose(h); FindClose(h);
if (count == 0) if (count == 0)
goto exit; goto exit;
list = malloc(count * sizeof(*list)); list = malloc(count * sizeof(*list));
if (!list) if (!list)
goto exit; goto exit;
h = FindFirstFileA(s, &fd); h = FindFirstFileA(s, &fd);
if (h == INVALID_HANDLE_VALUE) if (h == INVALID_HANDLE_VALUE)
goto exit; goto exit;
do { do {
if ((fd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)) if ((fd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY))
continue; continue;
if (is_valid_module_file(fd.cFileName) && i < count) { if (is_valid_module_file(fd.cFileName) && i < count) {
name_len = strlen(fd.cFileName); name_len = strlen(fd.cFileName);
if (name_len >= STK_PATH_MAX) if (name_len >= STK_PATH_MAX)
name_len = STK_PATH_MAX - 1; name_len = STK_PATH_MAX - 1;
memcpy(list[i], fd.cFileName, name_len); memcpy(list[i], fd.cFileName, name_len);
list[i][name_len] = '\0'; list[i][name_len] = '\0';
i++; i++;
} }
} while (FindNextFileA(h, &fd)); } while (FindNextFileA(h, &fd));
FindClose(h); FindClose(h);
goto exit; goto exit;
create_and_exit: create_and_exit:
platform_mkdir(dir_path); platform_mkdir(dir_path);
exit: exit:
*out_count = i; *out_count = i;
return list; return list;
#else #else
DIR *d; DIR *d;
struct dirent *e; struct dirent *e;
struct stat st; struct stat st;
char f[STK_PATH_MAX_OS]; char f[STK_PATH_MAX_OS];
d = opendir(dir_path); d = opendir(dir_path);
if (!d) if (!d)
goto create_and_exit; goto create_and_exit;
count_loop: count_loop:
e = readdir(d); e = readdir(d);
if (!e) if (!e)
goto count_done; goto count_done;
sprintf(f, "%s/%s", dir_path, e->d_name); sprintf(f, "%s/%s", dir_path, e->d_name);
if (!is_valid_module_file(e->d_name)) if (!is_valid_module_file(e->d_name))
goto count_loop; goto count_loop;
if (stat(f, &st) != 0 || !S_ISREG(st.st_mode)) if (stat(f, &st) != 0 || !S_ISREG(st.st_mode))
goto count_loop; goto count_loop;
count++; count++;
goto count_loop; goto count_loop;
count_done: count_done:
if (count == 0) if (count == 0)
goto close_and_exit; goto close_and_exit;
rewinddir(d); rewinddir(d);
list = malloc(count * sizeof(*list)); list = malloc(count * sizeof(*list));
if (!list) if (!list)
goto close_and_exit; goto close_and_exit;
fill_loop: fill_loop:
e = readdir(d); e = readdir(d);
if (!e || i >= count) if (!e || i >= count)
goto close_and_exit; goto close_and_exit;
sprintf(f, "%s/%s", dir_path, e->d_name); sprintf(f, "%s/%s", dir_path, e->d_name);
if (!is_valid_module_file(e->d_name)) if (!is_valid_module_file(e->d_name))
goto fill_loop; goto fill_loop;
if (stat(f, &st) != 0 || !S_ISREG(st.st_mode)) if (stat(f, &st) != 0 || !S_ISREG(st.st_mode))
goto fill_loop; goto fill_loop;
name_len = strlen(e->d_name); name_len = strlen(e->d_name);
if (name_len >= STK_PATH_MAX) { if (name_len >= STK_PATH_MAX) {
name_len = STK_PATH_MAX - 1; name_len = STK_PATH_MAX - 1;
} }
memcpy(list[i++], e->d_name, name_len); memcpy(list[i++], e->d_name, name_len);
list[i - 1][name_len] = '\0'; list[i - 1][name_len] = '\0';
goto fill_loop; goto fill_loop;
create_and_exit: create_and_exit:
platform_mkdir(dir_path); platform_mkdir(dir_path);
*out_count = 0; *out_count = 0;
return NULL; return NULL;
close_and_exit: close_and_exit:
closedir(d); closedir(d);
*out_count = i; *out_count = i;
return list; return list;
#endif #endif
} }
#if !defined(__linux__) && !defined(_WIN32) #if !defined(__linux__) && !defined(_WIN32)
static void update_watches(platform_watch_context_t *ctx) static void update_watches(platform_watch_context_t *ctx)
@@ -665,7 +662,7 @@ stk_module_event_t *platform_directory_watch_check(
int fd = (int)(long)handle; int fd = (int)(long)handle;
char buf[STK_EVENT_BUFFER]; char buf[STK_EVENT_BUFFER];
ssize_t len; ssize_t len;
size_t index = 0, count = 0, i; size_t index = 0, count = 0, i, write_idx;
stk_module_event_t *evs; stk_module_event_t *evs;
char *ptr, *end; char *ptr, *end;
struct inotify_event *e; struct inotify_event *e;
@@ -763,6 +760,21 @@ stk_module_event_t *platform_directory_watch_check(
} }
} }
write_idx = 0;
for (i = 0; i < index; ++i) {
if (evs[i] != -1) {
if (write_idx != i) {
evs[write_idx] = evs[i];
strncpy((*file_list)[write_idx],
(*file_list)[i], STK_PATH_MAX - 1);
(*file_list)[write_idx][STK_PATH_MAX - 1] =
'\0';
}
write_idx++;
}
}
index = write_idx;
*out_count = index; *out_count = index;
return evs; return evs;
src/stk.c
+2 -3
View File
@@ -242,9 +242,6 @@ begin_operations:
for (i = 0; i < unload_count; ++i) for (i = 0; i < unload_count; ++i)
stk_module_unload(unloaded_mod_indices[i]); stk_module_unload(unloaded_mod_indices[i]);
for (i = 0; i < reload_count; ++i)
stk_module_unload(reloaded_mod_indices[i]);
for (i = 0; i < reload_count; ++i) { for (i = 0; i < reload_count; ++i) {
int file_index = reloaded_mod_file_indices[i]; int file_index = reloaded_mod_file_indices[i];
int mod_index = reloaded_mod_indices[i]; int mod_index = reloaded_mod_indices[i];
@@ -261,6 +258,8 @@ begin_operations:
continue; continue;
} }
stk_module_unload(mod_index);
load_result = stk_module_load(tmp_path, mod_index); load_result = stk_module_load(tmp_path, mod_index);
if (load_result != STK_MOD_INIT_SUCCESS) { if (load_result != STK_MOD_INIT_SUCCESS) {
stk_log(stderr, "Failed to reload module %s: %s", stk_log(stderr, "Failed to reload module %s: %s",