#endif
#include <stdbool.h>
+#define MAX_ERRORS 5
void vlc_enable_override (void);
-static bool override = false;
-
-void vlc_enable_override (void)
-{
- override = true;
-}
-
-#if defined (__GNUC__) /* typeof and statement-expression */ \
+#if defined (__GNUC__) \
&& (defined (__ELF__) && !defined (__sun__))
/* Solaris crashes on printf("%s", NULL); which is legal, but annoying. */
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
+#include <string.h>
#include <dlfcn.h>
+#include <pthread.h>
+#ifdef HAVE_EXECINFO_H
+# include <execinfo.h>
+#endif
+#ifdef NDEBUG
+# undef HAVE_BACKTRACE
+#endif
+
+static bool override = false;
+
+static void vlc_reset_override (void)
+{
+ override = false;
+}
-static void vlogbug (const char *level, const char *func, const char *fmt,
- va_list ap)
+void vlc_enable_override (void)
{
+ override = true;
+ pthread_atfork (NULL, NULL, vlc_reset_override);
+}
+
+static void vlogbug (unsigned *pc, const char *level, const char *func,
+ const char *fmt, va_list ap)
+{
+#ifdef HAVE_BACKTRACE
+ const size_t framec = 5;
+ void *framev[framec];
+
+ backtrace (framev, framec);
+#endif
flockfile (stderr);
- fprintf (stderr, "%s: call to %s(", level, func);
- vfprintf (stderr, fmt, ap);
- fputs (")\n", stderr);
+ if (*pc < MAX_ERRORS)
+ {
+ (*pc)++;
+ 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);
}
-static void logbug (const char *level, const char *func, const char *fmt, ...)
+static void logbug (unsigned *pc, const char *level, const char *func,
+ const char *fmt, ...)
{
va_list ap;
va_start (ap, fmt);
- vlogbug (level, func, fmt, ap);
+ vlogbug (pc, level, func, fmt, ap);
va_end (ap);
}
void *sym = dlsym (RTLD_NEXT, name);
if (sym == NULL)
{
- fprintf (stderr, "Cannot resolve symbol %s!\n", name);
+ fprintf (stderr, "Cannot resolve symbol %s: %s\n", name,
+ dlerror ());
abort ();
}
return sym;
}
-#define LOG(level, ...) logbug(level, __func__, __VA_ARGS__)
+#define LOG(level, ...) \
+ do { \
+ static unsigned counter = 0; \
+ logbug(&counter, level, __func__, __VA_ARGS__); \
+ } while (0)
+
+/* Evil non-standard GNU C macro ;)
+ * typeof keyword,
+ * statement-expression,
+ * nested function...
+ */
#define CALL(func, ...) \
- ({ typeof (func) *sym = getsym ( # func); sym (__VA_ARGS__); })
+({ \
+ static typeof (func) *sym = NULL; \
+ static pthread_once_t once = PTHREAD_ONCE_INIT; \
+ auto void getsym_once (void); \
+ void getsym_once (void) \
+ { \
+ sym = getsym ( # func); \
+ } \
+ pthread_once (&once, getsym_once); \
+ sym (__VA_ARGS__); \
+})
+
+
+/*** Environment ***
+ *
+ * "Conforming multi-threaded applications shall not use the environ variable
+ * to access or modify any environment variable while any other thread is
+ * concurrently modifying any environment variable." -- POSIX.
+ *
+ * Some evil libraries modify the environment. We currently ignore the calls as
+ * they could crash the process. This may cause funny behaviour though. */
+int putenv (char *str)
+{
+ if (override)
+ {
+ LOG("Blocked", "\"%s\"", str);
+ return 0;
+ }
+ return CALL(putenv, str);
+}
+
+int setenv (const char *name, const char *value, int overwrite)
+{
+ if (override)
+ {
+ LOG("Blocked", "\"%s\", \"%s\", %d", name, value, overwrite);
+ return 0;
+ }
+ return CALL(setenv, name, value, overwrite);
+}
+
+int unsetenv (const char *name)
+{
+ if (override)
+ {
+ LOG("Blocked", "\"%s\"", name);
+ return 0;
+ }
+ return CALL(unsetenv, 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 struct
+{
+ pthread_mutex_t lock;
+ unsigned int seed;
+} prng = { PTHREAD_MUTEX_INITIALIZER, 0, };
+
+void srand (unsigned int seed)
+{
+ pthread_mutex_lock (&prng.lock);
+ LOG("Warning", "%d", seed);
+ prng.seed = seed;
+ pthread_mutex_unlock (&prng.lock);
+}
+
+int rand (void)
+{
+ int ret;
+
+ pthread_mutex_lock (&prng.lock);
+ LOG("Warning", "");
+ ret = rand_r (&prng.seed);
+ pthread_mutex_unlock (&prng.lock);
+ return ret;
+}
+
+
+#if 0
+/** Signals **/
+#include <signal.h>
+
+static bool blocked_signal (int num)
+{
+ switch (num)
+ {
+ case SIGINT:
+ case SIGHUP:
+ case SIGQUIT:
+ case SIGTERM:
+ case SIGPIPE:
+ case SIGCHLD:
+ return true;
+ }
+ return false;
+}
+
+void (*signal (int signum, void (*handler) (int))) (int)
+{
+ if (override)
+ {
+ if (handler != SIG_IGN && handler != SIG_DFL)
+ goto error;
+ if (!blocked_signal (signum))
+ goto error;
+ /* For our blocked signals, the handler won't matter much... */
+ if (handler == SIG_DFL)
+ LOG("Warning", "%d, SIG_DFL", signum, handler);
+ }
+ return CALL(signal, signum, handler);
+error:
+ LOG("Blocked", "%d, %p", signum, handler);
+ return SIG_DFL;
+}
+int sigaction (int signum, const struct sigaction *act, struct sigaction *old)
+{
+ if (override && act != NULL)
+ {
+ if ((act->sa_flags & SA_SIGINFO)
+ || (act->sa_handler != SIG_IGN && act->sa_handler != SIG_DFL))
+ goto error;
+ if (act->sa_handler == SIG_DFL)
+ LOG("Warning", "%d, %p, SIG_DFL", signum, act);
+ }
+ return CALL(sigaction, signum, act, old);
+error:
+ LOG("Blocked", "%d, %p, %p", signum, act, old);
+ return -1;
+}
+#endif
-#endif /* __ELF__ */
+
+/*** Locales ***
+ * setlocale() is not thread-safe and has a tendency to crash other threads as
+ * quite many libc and libintl calls depend on the locale.
+ * Use uselocale() instead for thread-safety.
+ */
+#include <locale.h>
+
+char *setlocale (int cat, const char *locale)
+{
+ if (override && locale != NULL)
+ {
+ LOG("Blocked", "%d, \"%s\"", cat, locale);
+ return NULL;
+ }
+ return CALL(setlocale, cat, locale);
+}
+
+
+/* strerror() is not thread-safe in theory (POSIX), nor in practice (glibc).
+ * This caused quite nasty crashes in the history of VLC/Linux. */
+char *strerror (int val)
+{
+ if (override)
+ {
+ static const char msg[] =
+ "Error message unavailable (use strerror_r instead of strerror)!";
+ LOG("Blocked", "%d", val);
+ return (char *)msg;
+ }
+ return CALL(strerror, val);
+}
+
+/*** Xlib ****/
+#ifdef HAVE_X11_XLIB_H
+# include <X11/Xlib.h>
+
+static pthread_mutex_t xlib_lock = PTHREAD_MUTEX_INITIALIZER;
+
+int (*XSetErrorHandler (int (*handler) (Display *, XErrorEvent *)))
+ (Display *, XErrorEvent *)
+{
+ if (override)
+ {
+ int (*ret) (Display *, XErrorEvent *);
+
+ pthread_mutex_lock (&xlib_lock);
+ LOG("Error", "%p", handler);
+ ret = CALL(XSetErrorHandler, handler);
+ pthread_mutex_unlock (&xlib_lock);
+ return ret;
+ }
+ return CALL(XSetErrorHandler, handler);
+}
+
+int (*XSetIOErrorHandler (int (*handler) (Display *))) (Display *)
+{
+ if (override)
+ {
+ int (*ret) (Display *);
+
+ pthread_mutex_lock (&xlib_lock);
+ LOG("Error", "%p", handler);
+ ret = CALL(XSetIOErrorHandler, handler);
+ pthread_mutex_unlock (&xlib_lock);
+ return ret;
+ }
+ return CALL(XSetIOErrorHandler, handler);
+}
+#endif
+#else
+void vlc_enable_override (void)
+{
+}
+#endif
projects / vlc / blobdiff