sysdeps/posix/libc_fatal.c

   1 /* Copyright (C) 1993-2013 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <atomic.h>
  19 #include <errno.h>
  20 #include <fcntl.h>
  21 #include <ldsodefs.h>
  22 #include <paths.h>
  23 #include <stdarg.h>
  24 #include <stdbool.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <sysdep.h>
  29 #include <unistd.h>
  30 #include <sys/syslog.h>
  31 #include <sys/uio.h>
  32 #include <not-cancel.h>
  33
  34 #ifdef FATAL_PREPARE_INCLUDE
  35 #include FATAL_PREPARE_INCLUDE
  36 #endif
  37
  38 struct str_list
  39 {
  40   const char *str;
  41   size_t len;
  42   struct str_list *next;
  43 };
  44
  45
  46 /* Abort with an error message.  */
  47 void
  48 __libc_message (int do_abort, const char *fmt, ...)
  49 {
  50   va_list ap;
  51   va_list ap_copy;
  52   int fd = -1;
  53
  54   va_start (ap, fmt);
  55   va_copy (ap_copy, ap);
  56
  57 #ifdef FATAL_PREPARE
  58   FATAL_PREPARE;
  59 #endif
  60
  61   /* Open a descriptor for /dev/tty unless the user explicitly
  62      requests errors on standard error.  */
  63   const char *on_2 = __libc_secure_getenv ("LIBC_FATAL_STDERR_");
  64   if (on_2 == NULL || *on_2 == '\0')
  65     fd = open_not_cancel_2 (_PATH_TTY, O_RDWR | O_NOCTTY | O_NDELAY);
  66
  67   if (fd == -1)
  68     fd = STDERR_FILENO;
  69
  70   struct str_list *list = NULL;
  71   int nlist = 0;
  72
  73   const char *cp = fmt;
  74   while (*cp != '\0')
  75     {
  76       /* Find the next "%s" or the end of the string.  */
  77       const char *next = cp;
  78       while (next[0] != '%' || next[1] != 's')
  79         {
  80           next = __strchrnul (next + 1, '%');
  81
  82           if (next[0] == '\0')
  83             break;
  84         }
  85
  86       /* Determine what to print.  */
  87       const char *str;
  88       size_t len;
  89       if (cp[0] == '%' && cp[1] == 's')
  90         {
  91           str = va_arg (ap, const char *);
  92           len = strlen (str);
  93           cp += 2;
  94         }
  95       else
  96         {
  97           str = cp;
  98           len = next - cp;
  99           cp = next;
 100         }
 101
 102       struct str_list *newp = alloca (sizeof (struct str_list));
 103       newp->str = str;
 104       newp->len = len;
 105       newp->next = list;
 106       list = newp;
 107       ++nlist;
 108     }
 109
 110   bool written = false;
 111   if (nlist > 0)
 112     {
 113       struct iovec *iov = alloca (nlist * sizeof (struct iovec));
 114       ssize_t total = 0;
 115
 116       for (int cnt = nlist - 1; cnt >= 0; --cnt)
 117         {
 118           iov[cnt].iov_base = (char *) list->str;
 119           iov[cnt].iov_len = list->len;
 120           total += list->len;
 121           list = list->next;
 122         }
 123
 124       if (TEMP_FAILURE_RETRY (__writev (fd, iov, nlist)) == total)
 125         written = true;
 126
 127       if (do_abort)
 128         {
 129           total = ((total + 1 + GLRO(dl_pagesize) - 1)
 130                    & ~(GLRO(dl_pagesize) - 1));
 131           struct abort_msg_s *buf = __mmap (NULL, total,
 132                                             PROT_READ | PROT_WRITE,
 133                                             MAP_ANON | MAP_PRIVATE, -1, 0);
 134           if (buf != MAP_FAILED)
 135             {
 136               buf->size = total;
 137               char *wp = buf->msg;
 138               for (int cnt = 0; cnt < nlist; ++cnt)
 139                 wp = mempcpy (wp, iov[cnt].iov_base, iov[cnt].iov_len);
 140               *wp = '\0';
 141
 142               /* We have to free the old buffer since the application might
 143                  catch the SIGABRT signal.  */
 144               struct abort_msg_s *old = atomic_exchange_acq (&__abort_msg,
 145                                                              buf);
 146               if (old != NULL)
 147                 __munmap (old, old->size);
 148             }
 149         }
 150     }
 151
 152   va_end (ap);
 153
 154   /* If we  had no success writing the message, use syslog.  */
 155   if (! written)
 156     vsyslog (LOG_ERR, fmt, ap_copy);
 157
 158   va_end (ap_copy);
 159
 160   if (do_abort)
 161     /* Kill the application.  */
 162     abort ();
 163 }
 164
 165
 166 void
 167 __libc_fatal (message)
 168      const char *message;
 169 {
 170   /* The loop is added only to keep gcc happy.  */
 171   while (1)
 172     __libc_message (1, "%s", message);
 173 }
 174 libc_hidden_def (__libc_fatal)