Add backtrace generation to MALLOC_DEBUG memory corruption reports

This patch allows astmm to access the backtrace generation code in Asterisk.
When memory is allocated, a backtrace is created and stored with the memory
region that tracks the allocation. If a memory corruption is detected, the
backtrace is printed to the astmm log. The backtrace will make use of the
BETTER_BACKTRACES build option if available.

As a result, this patch moves the backtrace generation code into its own file
and uses the non-wrapped versions of the C library memory allocation routines.
This allows the memory allocation code to safely use the backtrace generation
routines without infinitely recursing.

Review: https://reviewboard.asterisk.org/r/2567


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@391012 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 6 insertions, 195 deletions

diff --git a/main/logger.c b/main/logger.c
index fd0310a50..ae1537acd 100644
--- a/main/logger.c
+++ b/main/logger.c
@@ -45,6 +45,10 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 /* When we include logger.h again it will trample on some stuff in syslog.h, but
  * nothing we care about in here. */
 #include <syslog.h>
+#include <signal.h>
+#include <time.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 
 #include "asterisk/_private.h"
 #include "asterisk/paths.h"	/* use ast_config_AST_LOG_DIR */
@@ -64,19 +68,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include "asterisk/syslog.h"
 #include "asterisk/buildinfo.h"
 #include "asterisk/ast_version.h"
-
-#include <signal.h>
-#include <time.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-#ifdef HAVE_BKTR
-#include <execinfo.h>
-#define MAX_BACKTRACE_FRAMES 20
-#  if defined(HAVE_DLADDR) && defined(HAVE_BFD) && defined(BETTER_BACKTRACES)
-#    include <dlfcn.h>
-#    include <bfd.h>
-#  endif
-#endif
+#include "asterisk/backtrace.h"
 
 /*** DOCUMENTATION
  ***/
@@ -1576,189 +1568,8 @@ void ast_log_callid(int level, const char *file, int line, const char *function,
 	va_end(ap);
 }
 
-#ifdef HAVE_BKTR
-
-struct ast_bt *ast_bt_create(void)
-{
-	struct ast_bt *bt = ast_calloc(1, sizeof(*bt));
-	if (!bt) {
-		ast_log(LOG_ERROR, "Unable to allocate memory for backtrace structure!\n");
-		return NULL;
-	}
-
-	bt->alloced = 1;
-
-	ast_bt_get_addresses(bt);
-
-	return bt;
-}
-
-int ast_bt_get_addresses(struct ast_bt *bt)
-{
-	bt->num_frames = backtrace(bt->addresses, AST_MAX_BT_FRAMES);
-
-	return 0;
-}
-
-void *ast_bt_destroy(struct ast_bt *bt)
-{
-	if (bt->alloced) {
-		ast_free(bt);
-	}
-
-	return NULL;
-}
-
-char **ast_bt_get_symbols(void **addresses, size_t num_frames)
-{
-	char **strings = NULL;
-#if defined(BETTER_BACKTRACES)
-	int stackfr;
-	bfd *bfdobj;           /* bfd.h */
-	Dl_info dli;           /* dlfcn.h */
-	long allocsize;
-	asymbol **syms = NULL; /* bfd.h */
-	bfd_vma offset;        /* bfd.h */
-	const char *lastslash;
-	asection *section;
-	const char *file, *func;
-	unsigned int line;
-	char address_str[128];
-	char msg[1024];
-	size_t strings_size;
-	size_t *eachlen;
-#endif
-
-#if defined(BETTER_BACKTRACES)
-	strings_size = num_frames * sizeof(*strings);
-	eachlen = ast_calloc(num_frames, sizeof(*eachlen));
-
-	if (!(strings = ast_calloc(num_frames, sizeof(*strings)))) {
-		return NULL;
-	}
-
-	for (stackfr = 0; stackfr < num_frames; stackfr++) {
-		int found = 0, symbolcount;
-
-		msg[0] = '\0';
-
-		if (!dladdr(addresses[stackfr], &dli)) {
-			continue;
-		}
-
-		if (strcmp(dli.dli_fname, "asterisk") == 0) {
-			char asteriskpath[256];
-			if (!(dli.dli_fname = ast_utils_which("asterisk", asteriskpath, sizeof(asteriskpath)))) {
-				/* This will fail to find symbols */
-				ast_debug(1, "Failed to find asterisk binary for debug symbols.\n");
-				dli.dli_fname = "asterisk";
-			}
-		}
-
-		lastslash = strrchr(dli.dli_fname, '/');
-		if (	(bfdobj = bfd_openr(dli.dli_fname, NULL)) &&
-				bfd_check_format(bfdobj, bfd_object) &&
-				(allocsize = bfd_get_symtab_upper_bound(bfdobj)) > 0 &&
-				(syms = ast_malloc(allocsize)) &&
-				(symbolcount = bfd_canonicalize_symtab(bfdobj, syms))) {
-
-			if (bfdobj->flags & DYNAMIC) {
-				offset = addresses[stackfr] - dli.dli_fbase;
-			} else {
-				offset = addresses[stackfr] - (void *) 0;
-			}
-
-			for (section = bfdobj->sections; section; section = section->next) {
-				if (	!bfd_get_section_flags(bfdobj, section) & SEC_ALLOC ||
-						section->vma > offset ||
-						section->size + section->vma < offset) {
-					continue;
-				}
-
-				if (!bfd_find_nearest_line(bfdobj, section, syms, offset - section->vma, &file, &func, &line)) {
-					continue;
-				}
-
-				/* file can possibly be null even with a success result from bfd_find_nearest_line */
-				file = file ? file : "";
-
-				/* Stack trace output */
-				found++;
-				if ((lastslash = strrchr(file, '/'))) {
-					const char *prevslash;
-					for (prevslash = lastslash - 1; *prevslash != '/' && prevslash >= file; prevslash--);
-					if (prevslash >= file) {
-						lastslash = prevslash;
-					}
-				}
-				if (dli.dli_saddr == NULL) {
-					address_str[0] = '\0';
-				} else {
-					snprintf(address_str, sizeof(address_str), " (%p+%lX)",
-						dli.dli_saddr,
-						(unsigned long) (addresses[stackfr] - dli.dli_saddr));
-				}
-				snprintf(msg, sizeof(msg), "%s:%u %s()%s",
-					lastslash ? lastslash + 1 : file, line,
-					S_OR(func, "???"),
-					address_str);
-
-				break; /* out of section iteration */
-			}
-		}
-		if (bfdobj) {
-			bfd_close(bfdobj);
-			if (syms) {
-				ast_free(syms);
-			}
-		}
-
-		/* Default output, if we cannot find the information within BFD */
-		if (!found) {
-			if (dli.dli_saddr == NULL) {
-				address_str[0] = '\0';
-			} else {
-				snprintf(address_str, sizeof(address_str), " (%p+%lX)",
-					dli.dli_saddr,
-					(unsigned long) (addresses[stackfr] - dli.dli_saddr));
-			}
-			snprintf(msg, sizeof(msg), "%s %s()%s",
-				lastslash ? lastslash + 1 : dli.dli_fname,
-				S_OR(dli.dli_sname, "<unknown>"),
-				address_str);
-		}
-
-		if (!ast_strlen_zero(msg)) {
-			char **tmp;
-			eachlen[stackfr] = strlen(msg);
-			if (!(tmp = ast_realloc(strings, strings_size + eachlen[stackfr] + 1))) {
-				ast_free(strings);
-				strings = NULL;
-				break; /* out of stack frame iteration */
-			}
-			strings = tmp;
-			strings[stackfr] = (char *) strings + strings_size;
-			ast_copy_string(strings[stackfr], msg, eachlen[stackfr] + 1);
-			strings_size += eachlen[stackfr] + 1;
-		}
-	}
-
-	if (strings) {
-		/* Recalculate the offset pointers */
-		strings[0] = (char *) strings + num_frames * sizeof(*strings);
-		for (stackfr = 1; stackfr < num_frames; stackfr++) {
-			strings[stackfr] = strings[stackfr - 1] + eachlen[stackfr - 1] + 1;
-		}
-	}
-#else /* !defined(BETTER_BACKTRACES) */
-	strings = backtrace_symbols(addresses, num_frames);
-#endif /* defined(BETTER_BACKTRACES) */
-	return strings;
-}
-
-#endif /* HAVE_BKTR */
 
-void ast_backtrace(void)
+void ast_log_backtrace(void)
 {
 #ifdef HAVE_BKTR
 	struct ast_bt *bt;