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Add backtrace generation to MALLOC_DEBUG memory corruption reports

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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
This commit is contained in:
Matthew Jordan
2013-06-08 22:09:07 +00:00
parent 2fe6b6a533
commit c43f380d03
8 changed files with 360 additions and 256 deletions
Download Patch File Download Diff File Expand all files Collapse all files

201
main/logger.c
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@@ -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;