Global g_server variable in server.c is not thread-safe for signal handling #66

New Issue

2026-07-20T17:14:08+02:00

TapTap commented

2026-07-20 17:14:08 +02:00

Description

In src/server/server.c lines 115-123, a global variable g_server is used for cleanup on signals:

static Server* g_server = NULL;

static void cleanup(int sig) {
    (void)sig;
    if (g_server) {
        server_delete(&g_server);
    }
    _exit(0);
}

While the server uses fork() per connection (not threads), the _exit(0) in the signal handler is safe. However, the server_delete() call isn't async-signal-safe — it calls close(), SSL_CTX_free(), and free(), none of which are guaranteed to be safe inside a signal handler.

Location

src/server/server.c:115-123

Suggested Fix

Change the signal handler to only set a flag, and let the main loop check the flag:

static volatile sig_atomic_t g_shutdown_requested = 0;

static void cleanup(int sig) {
    (void)sig;
    g_shutdown_requested = 1;
}

Then in the accept loop, check g_shutdown_requested and break out to clean up properly.

Severity

Low

Category

Quality

## Description In `src/server/server.c` lines 115-123, a global variable `g_server` is used for cleanup on signals: ```c static Server* g_server = NULL; static void cleanup(int sig) { (void)sig; if (g_server) { server_delete(&g_server); } _exit(0); } ``` While the server uses `fork()` per connection (not threads), the `_exit(0)` in the signal handler is safe. However, the `server_delete()` call isn't async-signal-safe — it calls `close()`, `SSL_CTX_free()`, and `free()`, none of which are guaranteed to be safe inside a signal handler. ## Location `src/server/server.c:115-123` ## Suggested Fix Change the signal handler to only set a flag, and let the main loop check the flag: ```c static volatile sig_atomic_t g_shutdown_requested = 0; static void cleanup(int sig) { (void)sig; g_shutdown_requested = 1; } ``` Then in the accept loop, check `g_shutdown_requested` and break out to clean up properly. ## Severity Low ## Category Quality

TapTap referenced this issue

2026-07-20 18:37:04 +02:00

Fix logic/correctness bugs (#73, #68, #67, #66, #59, #58, #54, #48, #53) #78

TapTap referenced this issue from a commit

2026-07-20 19:04:40 +02:00

fix: logic/correctness bugs — issues #73, #68, #67, #66, #59, #58, #54, #48, #53

TapTap referenced this issue

2026-07-20 19:04:42 +02:00

Fix logic/correctness bugs (#73, #68, #67, #66, #59, #58, #54, #48, #53) #82

TapTap referenced this issue from a commit

2026-07-20 19:05:03 +02:00

Merge pull request 'Fix logic/correctness bugs (#73, #68, #67, #66, #59, #58, #54, #48, #53)' (#82) from fix/logic-correctness into main