Merged revisions 298960 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.8

................
  r298960 | tilghman | 2010-12-17 17:52:04 -0600 (Fri, 17 Dec 2010) | 20 lines
  
  Merged revisions 298957 via svnmerge from 
  https://origsvn.digium.com/svn/asterisk/branches/1.6.2
  
  ................
    r298957 | tilghman | 2010-12-17 17:30:55 -0600 (Fri, 17 Dec 2010) | 13 lines
    
    Merged revisions 298905 via svnmerge from 
    https://origsvn.digium.com/svn/asterisk/branches/1.4
    
    ........
      r298905 | tilghman | 2010-12-17 15:40:56 -0600 (Fri, 17 Dec 2010) | 6 lines
      
      Let Asterisk find better backtrace information with libbfd.
      
      The menuselect option BETTER_BACKTRACES, if enabled, will use libbfd to search
      for better symbol information within both the Asterisk binary, as well as
      loaded modules, to assist when using inline backtraces to track down problems.

      Review: https://reviewboard.asterisk.org/r/1055/
    ........
  ................
................


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@298961 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 150 insertions, 2 deletions

diff --git a/main/logger.c b/main/logger.c
index 430f01f58..12f835f99 100644
--- a/main/logger.c
+++ b/main/logger.c
@@ -56,6 +56,10 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #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
 
 static char dateformat[256] = "%b %e %T";		/* Original Asterisk Format */
@@ -1213,6 +1217,150 @@ void *ast_bt_destroy(struct ast_bt *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_log(LOG_DEBUG, "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;
+				}
+
+				/* 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)
@@ -1227,7 +1375,7 @@ void ast_backtrace(void)
 		return;
 	}
 
-	if ((strings = backtrace_symbols(bt->addresses, bt->num_frames))) {
+	if ((strings = ast_bt_get_symbols(bt->addresses, bt->num_frames))) {
 		ast_debug(1, "Got %d backtrace record%c\n", bt->num_frames, bt->num_frames != 1 ? 's' : ' ');
 		for (i = 3; i < bt->num_frames - 2; i++) {
 			ast_log(LOG_DEBUG, "#%d: [%p] %s\n", i - 3, bt->addresses[i], strings[i]);
@@ -1242,7 +1390,7 @@ void ast_backtrace(void)
 	ast_bt_destroy(bt);
 #else
 	ast_log(LOG_WARNING, "Must run configure with '--with-execinfo' for stack backtraces.\n");
-#endif
+#endif /* defined(HAVE_BKTR) */
 }
 
 void __ast_verbose_ap(const char *file, int line, const char *func, const char *fmt, va_list ap)