Add small backtrace

[vlc] / bin / override.c

diff --git a/bin/override.c b/bin/override.c
index 5098a7d59823e329a3c9e6469a72e1fdece1b84d..c98ff81deba45f8e97d1d6be5dda0d30dc4e768e 100644 (file)
--- a/bin/override.c
+++ b/bin/override.c
@@ -41,14 +41,28 @@ void vlc_enable_override (void)
 #include <stdio.h>
 #include <stdlib.h>
 #include <dlfcn.h>
+#include <pthread.h>
+#ifdef HAVE_EXECINFO_H
+# include <execinfo.h>
+#endif
 
 static void vlogbug (const char *level, const char *func, const char *fmt,
                      va_list ap)
 {
+#ifdef HAVE_BACKTRACE
+    const size_t framec = 8;
+    void *framev[framec];
+
+    backtrace (framev, framec);
+#endif
     flockfile (stderr);
     fprintf (stderr, "%s: call to %s(", level, func);
     vfprintf (stderr, fmt, ap);
     fputs (")\n", stderr);
+    fflush (stderr);
+#ifdef HAVE_BACKTRACE
+    backtrace_symbols_fd (framev + 2, framec - 2, fileno (stderr));
+#endif
     funlockfile (stderr);
 }
 
@@ -116,4 +130,60 @@ int unsetenv (const char *name)
 }
 
 
+/*** Pseudo random numbers ***
+ *
+ * The C PRNG is not thread-safe (and generally sucks, the POSIX 48-bits PRNG
+ * is much better as a reproducible non-secure PRNG). To work around this, we
+ * force evil callers to serialize. This makes the call safe, but fails to
+ * preserve reproducibility of the number sequence (which usually does not
+ * matter).
+ **/
+static pthread_mutex_t prng_lock = PTHREAD_MUTEX_INITIALIZER;
+
+void srand (unsigned int seed)
+{
+    pthread_mutex_lock (&prng_lock);
+    LOG("Warning", "%d", seed);
+    CALL(srand, seed);
+    pthread_mutex_unlock (&prng_lock);
+}
+
+int rand (void)
+{
+    int ret;
+
+    pthread_mutex_lock (&prng_lock);
+    LOG("Warning", "");
+    ret = CALL(rand);
+    pthread_mutex_unlock (&prng_lock);
+    return ret;
+}
+
+
+/** Signals **/
+#include <signal.h>
+
+void (*signal (int signum, void (*handler) (int))) (int)
+{
+    if (override)
+    {
+        const char *msg = "Error";
+
+        if ((signum == SIGPIPE && handler == SIG_IGN)
+         || (signum != SIGPIPE && handler == SIG_DFL))
+            /* Same settings we already use */
+            msg = "Warning";
+        LOG(msg, "%d, %p", signum, handler);
+    }
+    return CALL(signal, signum, handler);
+}
+
+int sigaction (int signum, const struct sigaction *act, struct sigaction *old)
+{
+    if (act != NULL)
+        LOG("Error", "%d, %p, %p", signum, act, old);
+    return CALL(sigaction, signum, act, old);
+}
+
+
 #endif /* __ELF__ */