static void
backtrace_and_maps (int do_abort, bool written, int fd)
{
if (do_abort > 1 && written)
{
void *addrs[64];
#define naddrs (sizeof (addrs) / sizeof (addrs[0]))
int n = __backtrace (addrs, naddrs);
if (n > 2)
{
#define strnsize(str) str, strlen (str)
#define writestr(str) write_not_cancel (fd, str)
writestr (strnsize ("======= Backtrace: =========\n"));
__backtrace_symbols_fd (addrs + 1, n - 1, fd);
writestr (strnsize ("======= Memory map: ========\n"));
int fd2 = open_not_cancel_2 ("/proc/self/maps", O_RDONLY);
char buf[1024];
ssize_t n2;
while ((n2 = read_not_cancel (fd2, buf, sizeof (buf))) > 0)
if (write_not_cancel (fd, buf, n2) != n2)
break;
close_not_cancel_no_status (fd2);
}
}
}
/* This function is called when a segmentation fault is caught. The system
is in an unstable state now. This means especially that malloc() might
not work anymore. */
static void
catch_segfault (int signal, SIGCONTEXT ctx)
{
int fd, cnt, i;
void **arr;
struct sigaction sa;
uintptr_t pc;
/* This is the name of the file we are writing to. If none is given
or we cannot write to this file write to stderr. */
fd = 2;
if (fname != NULL)
{
fd = open (fname, O_TRUNC | O_WRONLY | O_CREAT, 0666);
if (fd == -1)
fd = 2;
}
WRITE_STRING ("*** ");
write_strsignal (fd, signal);
WRITE_STRING ("\n");
#ifdef REGISTER_DUMP
REGISTER_DUMP;
#endif
#if __OPTION_EGLIBC_BACKTRACE
WRITE_STRING ("\nBacktrace:\n");
/* Get the backtrace. */
arr = alloca (256 * sizeof (void *));
cnt = backtrace (arr, 256);
/* Now try to locate the PC from signal context in the backtrace.
Normally it will be found at arr[2], but it might appear later
if there were some signal handler wrappers. Allow a few bytes
difference to cope with as many arches as possible. */
pc = (uintptr_t) GET_PC (ctx);
for (i = 0; i < cnt; ++i)
if ((uintptr_t) arr[i] >= pc - 16 && (uintptr_t) arr[i] <= pc + 16)
break;
/* If we haven't found it, better dump full backtrace even including
the signal handler frames instead of not dumping anything. */
if (i == cnt)
i = 0;
/* Now generate nicely formatted output. */
__backtrace_symbols_fd (arr + i, cnt - i, fd);
#endif
#ifdef HAVE_PROC_SELF
/* Now the link map. */
int mapfd = open ("/proc/self/maps", O_RDONLY);
if (mapfd != -1)
{
write (fd, "\nMemory map:\n\n", 14);
char buf[256];
ssize_t n;
while ((n = TEMP_FAILURE_RETRY (read (mapfd, buf, sizeof (buf)))) > 0)
TEMP_FAILURE_RETRY (write (fd, buf, n));
close (mapfd);
}
#endif
/* Pass on the signal (so that a core file is produced). */
sa.sa_handler = SIG_DFL;
sigemptyset (&sa.sa_mask);
sa.sa_flags = 0;
sigaction (signal, &sa, NULL);
raise (signal);
}
/* This function is called when a segmentation fault is caught. The system
is in an instable state now. This means especially that malloc() might
not work anymore. */
static void
catch_segfault (int signal, SIGCONTEXT ctx)
{
struct layout *current;
void *__unbounded top_frame;
void *__unbounded top_stack;
int fd;
void **arr;
size_t cnt;
struct sigaction sa;
/* This is the name of the file we are writing to. If none is given
or we cannot write to this file write to stderr. */
fd = 2;
if (fname != NULL)
{
fd = open (fname, O_TRUNC | O_WRONLY | O_CREAT, 0666);
if (fd == -1)
fd = 2;
}
WRITE_STRING ("*** ");
write_strsignal (fd, signal);
WRITE_STRING ("\n");
#ifdef REGISTER_DUMP
REGISTER_DUMP;
#endif
WRITE_STRING ("\nBacktrace:\n");
top_frame = GET_FRAME (ctx);
top_stack = GET_STACK (ctx);
/* First count how many entries we'll have. */
cnt = 1;
current = BOUNDED_1 ((struct layout *) top_frame);
while (!((void *) current INNER_THAN top_stack
|| !((void *) current INNER_THAN __libc_stack_end)))
{
++cnt;
current = ADVANCE_STACK_FRAME (current->next);
}
arr = alloca (cnt * sizeof (void *));
/* First handle the program counter from the structure. */
arr[0] = GET_PC (ctx);
current = BOUNDED_1 ((struct layout *) top_frame);
cnt = 1;
while (!((void *) current INNER_THAN top_stack
|| !((void *) current INNER_THAN __libc_stack_end)))
{
arr[cnt++] = current->return_address;
current = ADVANCE_STACK_FRAME (current->next);
}
/* If the last return address was NULL, assume that it doesn't count. */
if (arr[cnt-1] == NULL)
cnt--;
/* Now generate nicely formatted output. */
__backtrace_symbols_fd (arr, cnt, fd);
/* Pass on the signal (so that a core file is produced). */
sa.sa_handler = SIG_DFL;
sigemptyset (&sa.sa_mask);
sa.sa_flags = 0;
sigaction (signal, &sa, NULL);
raise (signal);
}
