Remove dependency on signal() function

Replaces uses of signal() with sigaction() which should be far more portable.
2023-10-02 16:29:06 +01:00
parent bce303c3a8
commit d11617adbe
6 changed files with 191 additions and 10 deletions
@@ -2987,10 +2987,28 @@ g_set_alarm(void (*func)(int), unsigned int secs)
 #if defined(_WIN32)
    return 0;
 #else
+    struct sigaction action;
+
    /* Cancel any previous alarm to prevent a race */
    unsigned int rv = alarm(0);
-    signal(SIGALRM, func);
-    (void)alarm(secs);
+
+    if (func == NULL)
+    {
+        action.sa_handler = SIG_DFL;
+        action.sa_flags = 0;
+    }
+    else
+    {
+        action.sa_handler = func;
+        action.sa_flags = SA_RESTART;
+    }
+    sigemptyset (&action.sa_mask);
+
+    sigaction(SIGALRM, &action, NULL);
+    if (func != NULL && secs > 0)
+    {
+        (void)alarm(secs);
+    }
    return rv;
 #endif
 }
@@ -3002,7 +3020,22 @@ g_signal_child_stop(void (*func)(int))
 {
 #if defined(_WIN32)
 #else
-    signal(SIGCHLD, func);
+    struct sigaction action;
+
+    if (func == NULL)
+    {
+        action.sa_handler = SIG_DFL;
+        action.sa_flags = 0;
+    }
+    else
+    {
+        action.sa_handler = func;
+        // Don't need to know when children are stopped or started
+        action.sa_flags = (SA_RESTART | SA_NOCLDSTOP);
+    }
+    sigemptyset (&action.sa_mask);
+
+    sigaction(SIGCHLD, &action, NULL);
 #endif
 }

@@ -3013,7 +3046,21 @@ g_signal_segfault(void (*func)(int))
 {
 #if defined(_WIN32)
 #else
-    signal(SIGSEGV, func);
+    struct sigaction action;
+
+    if (func == NULL)
+    {
+        action.sa_handler = SIG_DFL;
+        action.sa_flags = 0;
+    }
+    else
+    {
+        action.sa_handler = func;
+        action.sa_flags = SA_RESETHAND; // This is a one-shot
+    }
+    sigemptyset (&action.sa_mask);
+
+    sigaction(SIGSEGV, &action, NULL);
 #endif
 }

@@ -3024,7 +3071,21 @@ g_signal_hang_up(void (*func)(int))
 {
 #if defined(_WIN32)
 #else
-    signal(SIGHUP, func);
+    struct sigaction action;
+
+    if (func == NULL)
+    {
+        action.sa_handler = SIG_DFL;
+        action.sa_flags = 0;
+    }
+    else
+    {
+        action.sa_handler = func;
+        action.sa_flags = SA_RESTART;
+    }
+    sigemptyset (&action.sa_mask);
+
+    sigaction(SIGHUP, &action, NULL);
 #endif
 }

@@ -3035,7 +3096,21 @@ g_signal_user_interrupt(void (*func)(int))
 {
 #if defined(_WIN32)
 #else
-    signal(SIGINT, func);
+    struct sigaction action;
+
+    if (func == NULL)
+    {
+        action.sa_handler = SIG_DFL;
+        action.sa_flags = 0;
+    }
+    else
+    {
+        action.sa_handler = func;
+        action.sa_flags = SA_RESTART;
+    }
+    sigemptyset (&action.sa_mask);
+
+    sigaction(SIGINT, &action, NULL);
 #endif
 }

@@ -3046,7 +3121,21 @@ g_signal_terminate(void (*func)(int))
 {
 #if defined(_WIN32)
 #else
-    signal(SIGTERM, func);
+    struct sigaction action;
+
+    if (func == NULL)
+    {
+        action.sa_handler = SIG_DFL;
+        action.sa_flags = 0;
+    }
+    else
+    {
+        action.sa_handler = func;
+        action.sa_flags = SA_RESTART;
+    }
+    sigemptyset (&action.sa_mask);
+
+    sigaction(SIGTERM, &action, NULL);
 #endif
 }

@@ -3057,7 +3146,21 @@ g_signal_pipe(void (*func)(int))
 {
 #if defined(_WIN32)
 #else
-    signal(SIGPIPE, func);
+    struct sigaction action;
+
+    if (func == NULL)
+    {
+        action.sa_handler = SIG_DFL;
+        action.sa_flags = 0;
+    }
+    else
+    {
+        action.sa_handler = func;
+        action.sa_flags = SA_RESTART;
+    }
+    sigemptyset (&action.sa_mask);
+
+    sigaction(SIGPIPE, &action, NULL);
 #endif
 }

@@ -3068,7 +3171,21 @@ g_signal_usr1(void (*func)(int))
 {
 #if defined(_WIN32)
 #else
-    signal(SIGUSR1, func);
+    struct sigaction action;
+
+    if (func == NULL)
+    {
+        action.sa_handler = SIG_DFL;
+        action.sa_flags = 0;
+    }
+    else
+    {
+        action.sa_handler = func;
+        action.sa_flags = SA_RESTART;
+    }
+    sigemptyset (&action.sa_mask);
+
+    sigaction(SIGUSR1, &action, NULL);
 #endif
 }

@@ -176,6 +176,14 @@ g_sck_get_peer_ip_address(int sck,
 const char *
 g_sck_get_peer_description(int sck,
                           char *desc, unsigned int bytes);
+/**
+ * Sleep for the specified number of milli-seconds
+ * @param msecs Milli-seconds
+ *
+ * If a signal is processed, it is possible that this call will
+ * sleep for less than the specified number of milli-seconds. This
+ * is platform-specific
+ */
 void     g_sleep(int msecs);
 int      g_pipe(int fd[2]);

@@ -275,13 +283,56 @@ int      g_execvp(const char *p1, char *args[]);
 */
 int      g_execvp_list(const char *file, struct list *argv);
 int      g_execlp3(const char *a1, const char *a2, const char *a3);
+/**
+ * Set an alarm using SIGALRM
+ * @param func Signal handler, or NULL to cancel an alarm
+ * @param secs Number of seconds until an alarm is raised
+ * @return Number of seconds remaining before a previously requested
+ *         alarm is raised
+ */
 unsigned int g_set_alarm(void (*func)(int), unsigned int secs);
+/**
+ * Set a handler up for SIGCHLD
+ * @param func signal handler, or NULL to restore the default handler
+ * The handler remains in place until explicitly replaced.
+ */
 void     g_signal_child_stop(void (*func)(int));
+/**
+ * Set a handler up for SIGSEGV
+ * @param func signal handler, or NULL to restore the default handler
+ * The handler can only be called once, at which point the
+ * default handler is restored. This is to avoid infinite loops
+ */
 void     g_signal_segfault(void (*func)(int));
+/**
+ * Set a handler up for SIGHUP
+ * @param func signal handler, or NULL to restore the default handler
+ * The handler remains in place until explicitly replaced.
+ */
 void     g_signal_hang_up(void (*func)(int));
+/**
+ * Set a handler up for SIGINT
+ * @param func signal handler, or NULL to restore the default handler
+ * The handler remains in place until explicitly replaced.
+ */
 void     g_signal_user_interrupt(void (*func)(int));
+/**
+ * Set a handler up for SIGTERM
+ * @param func signal handler, or NULL to restore the default handler
+ * The handler remains in place until explicitly replaced.
+ */
 void     g_signal_terminate(void (*func)(int));
+/**
+ * Set a handler up for SIGPIPE
+ * @param func signal handler, or NULL to restore the default handler
+ * The handler remains in place until explicitly replaced.
+ */
 void     g_signal_pipe(void (*func)(int));
+/**
+ * Set a handler up for SIGUSR1
+ * @param func signal handler, or NULL to restore the default handler
+ * The handler remains in place until explicitly replaced.
+ */
 void     g_signal_usr1(void (*func)(int));
 int      g_fork(void);
 int      g_setgid(int pid);