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Print backtrace in a signal-safe manner

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Backtraces are often printed in signal context, such as when a segfault
occurs.

Signed-off-by: Chase Douglas <chase.douglas@canonical.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

os: print offset as unsigned int, not long unsigned int

pnprintf() takes unsigned int for %u

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
This commit is contained in:
Chase Douglas 2012-04-06 16:09:05 -07:00 committed by Keith Packard
parent ac20815d52
commit 0fa5217836
1 changed files with 29 additions and 20 deletions
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49
os/backtrace.c
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@ -45,29 +45,37 @@ xorg_backtrace(void)
int size, i;
Dl_info info;
ErrorF("\n");
ErrorF("Backtrace:\n");
ErrorFSigSafe("\n");
ErrorFSigSafe("Backtrace:\n");
size = backtrace(array, 64);
for (i = 0; i < size; i++) {
int rc = dladdr(array[i], &info);
if (rc == 0) {
ErrorF("%d: ?? [%p]\n", i, array[i]);
ErrorFSigSafe("%u: ?? [%p]\n", i, array[i]);
continue;
}
mod = (info.dli_fname && *info.dli_fname) ? info.dli_fname : "(vdso)";
if (info.dli_saddr)
ErrorF("%d: %s (%s+0x%lx) [%p]\n", i, mod,
info.dli_sname,
(long unsigned int) ((char *) array[i] -
(char *) info.dli_saddr), array[i]);
ErrorFSigSafe(
"%u: %s (%s+0x%x) [%p]\n",
i,
mod,
info.dli_sname,
(unsigned int)((char *) array[i] -
(char *) info.dli_saddr),
array[i]);
else
ErrorF("%d: %s (%p+0x%lx) [%p]\n", i, mod,
info.dli_fbase,
(long unsigned int) ((char *) array[i] -
(char *) info.dli_fbase), array[i]);
ErrorFSigSafe(
"%u: %s (%p+0x%x) [%p]\n",
i,
mod,
info.dli_fbase,
(unsigned int)((char *) array[i] -
(char *) info.dli_fbase),
array[i]);
}
ErrorF("\n");
ErrorFSigSafe("\n");
}
#else /* not glibc or glibc < 2.1 */
@ -105,7 +113,7 @@ xorg_backtrace_frame(uintptr_t pc, int signo, void *arg)
strcpy(signame, "unknown");
}
ErrorF("** Signal %d (%s)\n", signo, signame);
ErrorFSigSafe("** Signal %u (%s)\n", signo, signame);
}
snprintf(header, sizeof(header), "%d: 0x%lx", depth, pc);
@ -123,7 +131,8 @@ xorg_backtrace_frame(uintptr_t pc, int signo, void *arg)
symname = "<section start>";
offset = pc - (uintptr_t) dlinfo.dli_fbase;
}
ErrorF("%s: %s:%s+0x%lx\n", header, dlinfo.dli_fname, symname, offset);
ErrorFSigSafe("%s: %s:%s+0x%x\n", header, dlinfo.dli_fname, symname,
offset);
}
else {
@ -131,7 +140,7 @@ xorg_backtrace_frame(uintptr_t pc, int signo, void *arg)
* probably poke elfloader here, but haven't written that code yet,
* so we just print the pc.
*/
ErrorF("%s\n", header);
ErrorFSigSafe("%s\n", header);
}
return 0;
@ -183,7 +192,7 @@ xorg_backtrace_pstack(void)
if (bytesread > 0) {
btline[bytesread] = 0;
ErrorF("%s", btline);
ErrorFSigSafe("%s", btline);
}
else if ((bytesread < 0) || ((errno != EINTR) && (errno != EAGAIN)))
done = 1;
@ -203,8 +212,8 @@ void
xorg_backtrace(void)
{
ErrorF("\n");
ErrorF("Backtrace:\n");
ErrorFSigSafe("\n");
ErrorFSigSafe("Backtrace:\n");
#ifdef HAVE_PSTACK
/* First try fork/exec of pstack - otherwise fall back to walkcontext
@ -221,9 +230,9 @@ xorg_backtrace(void)
walkcontext(&u, xorg_backtrace_frame, &depth);
else
#endif
ErrorF("Failed to get backtrace info: %s\n", strerror(errno));
ErrorFSigSafe("Failed to get backtrace info: %s\n", strerror(errno));
}
ErrorF("\n");
ErrorFSigSafe("\n");
}
#else