libshouldbeinlibc: Add backtrace_stderr and backtrace_mach

as convenience for printing a backtrace without erroring out.

2 files changed, 41 insertions, 2 deletions

diff --git a/libshouldbeinlibc/assert-backtrace.c b/libshouldbeinlibc/assert-backtrace.c
index 66ce47c1..7c6fac51 100644
--- a/libshouldbeinlibc/assert-backtrace.c
+++ b/libshouldbeinlibc/assert-backtrace.c
@@ -26,9 +26,13 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include <mach/mach_traps.h>
 
 #include "assert-backtrace.h"
 
+static const size_t size = 128;
+static const size_t skip = 2;
+
 static void __attribute__ ((noreturn))
 __assert_fail_base_backtrace (const char *fmt,
 			      const char *assertion,
@@ -36,8 +40,6 @@ __assert_fail_base_backtrace (const char *fmt,
 			      unsigned int line,
 			      const char *function)
 {
-  const size_t size = 128;
-  const size_t skip = 2;
   int nptrs;
   void *buffer[size];
 
@@ -79,4 +81,35 @@ __assert_perror_fail_backtrace (int errnum,
 
 }
 
+void
+backtrace_stderr (void)
+{
+  int nptrs;
+  void *buffer[size];
+
+  nptrs = backtrace (buffer, size);
+  backtrace_symbols_fd (buffer, nptrs, STDERR_FILENO);
+  fflush (stderr);
+}
+
+void
+backtrace_mach (void)
+{
+  int nptrs;
+  void *buffer[size];
+  char **symbols;
+  int i;
+
+  nptrs = backtrace (buffer, size);
+  symbols = backtrace_symbols (buffer, nptrs);
+
+  for (i = 0; i < nptrs; i++)
+    {
+      mach_print(symbols[i]);
+      mach_print("\n");
+    }
+
+  free(symbols);
+}
+
 #endif /* ! defined NDEBUG */
diff --git a/libshouldbeinlibc/assert-backtrace.h b/libshouldbeinlibc/assert-backtrace.h
index c1e51594..84a9e7c1 100644
--- a/libshouldbeinlibc/assert-backtrace.h
+++ b/libshouldbeinlibc/assert-backtrace.h
@@ -58,5 +58,11 @@ void __assert_perror_fail_backtrace (int errnum,
 				     __FILE__, __LINE__,		\
 				     __PRETTY_FUNCTION__))
 
+/* Print a stack trace on stderr.  */
+void backtrace_stderr (void);
+
+/* Print a stack trace on the mach console.  */
+void backtrace_mach (void);
+
 #endif /* NDEBUG */
 #endif /* __ASSERT_BACKTRACE__ */