sysdeps/unix/sysv/linux/libc_fatal.c

   1 /* Catastrophic failure reports.  Linux version.
   2    Copyright (C) 1993-2017 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <execinfo.h>
  21 #include <fcntl.h>
  22 #include <not-cancel.h>
  23 #include <string.h>
  24 #include <sys/mman.h>
  25 #include <sys/uio.h>
  26
  27 static bool
  28 writev_for_fatal (int fd, const struct iovec *iov, size_t niov, size_t total)
  29 {
  30   INTERNAL_SYSCALL_DECL (err);
  31   ssize_t cnt;
  32   do
  33     cnt = INTERNAL_SYSCALL (writev, err, 3, fd, iov, niov);
  34   while (INTERNAL_SYSCALL_ERROR_P (cnt, err)
  35          && INTERNAL_SYSCALL_ERRNO (cnt, err) == EINTR);
  36   return cnt == total;
  37 }
  38 #define WRITEV_FOR_FATAL        writev_for_fatal
  39
  40 static void
  41 backtrace_and_maps (int do_abort, bool written, int fd)
  42 {
  43   if (do_abort > 1 && written)
  44     {
  45       void *addrs[64];
  46 #define naddrs (sizeof (addrs) / sizeof (addrs[0]))
  47       int n = __backtrace (addrs, naddrs);
  48       if (n > 2)
  49         {
  50 #define strnsize(str) str, strlen (str)
  51 #define writestr(str) write_not_cancel (fd, str)
  52           writestr (strnsize ("======= Backtrace: =========\n"));
  53           __backtrace_symbols_fd (addrs + 1, n - 1, fd);
  54
  55           writestr (strnsize ("======= Memory map: ========\n"));
  56           int fd2 = __open_nocancel ("/proc/self/maps", O_RDONLY);
  57           char buf[1024];
  58           ssize_t n2;
  59           while ((n2 = __read_nocancel (fd2, buf, sizeof (buf))) > 0)
  60             if (write_not_cancel (fd, buf, n2) != n2)
  61               break;
  62           close_not_cancel_no_status (fd2);
  63         }
  64     }
  65 }
  66 #define BEFORE_ABORT            backtrace_and_maps
  67
  68 #include <sysdeps/posix/libc_fatal.c>