sysdeps/posix/libc_fatal.c

   1 /* Copyright (C) 1993-1995,1997,2000,2004,2005,2009,2011
   2         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 <atomic.h>
  20 #include <errno.h>
  21 #include <fcntl.h>
  22 #include <ldsodefs.h>
  23 #include <paths.h>
  24 #include <stdarg.h>
  25 #include <stdbool.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <sysdep.h>
  30 #include <unistd.h>
  31 #include <sys/syslog.h>
  32 #include <sys/uio.h>
  33 #include <not-cancel.h>
  34
  35 #ifdef FATAL_PREPARE_INCLUDE
  36 #include FATAL_PREPARE_INCLUDE
  37 #endif
  38
  39 struct str_list
  40 {
  41   const char *str;
  42   size_t len;
  43   struct str_list *next;
  44 };
  45
  46
  47 /* Abort with an error message.  */
  48 void
  49 __libc_message (int do_abort, const char *fmt, ...)
  50 {
  51   va_list ap;
  52   va_list ap_copy;
  53   int fd = -1;
  54
  55   va_start (ap, fmt);
  56   va_copy (ap_copy, ap);
  57
  58 #ifdef FATAL_PREPARE
  59   FATAL_PREPARE;
  60 #endif
  61
  62   /* Open a descriptor for /dev/tty unless the user explicitly
  63      requests errors on standard error.  */
  64   const char *on_2 = __secure_getenv ("LIBC_FATAL_STDERR_");
  65   if (on_2 == NULL || *on_2 == '\0')
  66     fd = open_not_cancel_2 (_PATH_TTY, O_RDWR | O_NOCTTY | O_NDELAY);
  67
  68   if (fd == -1)
  69     fd = STDERR_FILENO;
  70
  71   struct str_list *list = NULL;
  72   int nlist = 0;
  73
  74   const char *cp = fmt;
  75   while (*cp != '\0')
  76     {
  77       /* Find the next "%s" or the end of the string.  */
  78       const char *next = cp;
  79       while (next[0] != '%' || next[1] != 's')
  80         {
  81           next = __strchrnul (next + 1, '%');
  82
  83           if (next[0] == '\0')
  84             break;
  85         }
  86
  87       /* Determine what to print.  */
  88       const char *str;
  89       size_t len;
  90       if (cp[0] == '%' && cp[1] == 's')
  91         {
  92           str = va_arg (ap, const char *);
  93           len = strlen (str);
  94           cp += 2;
  95         }
  96       else
  97         {
  98           str = cp;
  99           len = next - cp;
 100           cp = next;
 101         }
 102
 103       struct str_list *newp = alloca (sizeof (struct str_list));
 104       newp->str = str;
 105       newp->len = len;
 106       newp->next = list;
 107       list = newp;
 108       ++nlist;
 109     }
 110
 111   bool written = false;
 112   if (nlist > 0)
 113     {
 114       struct iovec *iov = alloca (nlist * sizeof (struct iovec));
 115       ssize_t total = 0;
 116
 117       for (int cnt = nlist - 1; cnt >= 0; --cnt)
 118         {
 119           iov[cnt].iov_base = (char *) list->str;
 120           iov[cnt].iov_len = list->len;
 121           total += list->len;
 122           list = list->next;
 123         }
 124
 125       if (TEMP_FAILURE_RETRY (__writev (fd, iov, nlist)) == total)
 126         written = true;
 127
 128       if (do_abort)
 129         {
 130           total = ((total + 1 + GLRO(dl_pagesize) - 1)
 131                    & ~(GLRO(dl_pagesize) - 1));
 132           struct abort_msg_s *buf = __mmap (NULL, total,
 133                                             PROT_READ | PROT_WRITE,
 134                                             MAP_ANON | MAP_PRIVATE, -1, 0);
 135           if (buf != MAP_FAILED)
 136             {
 137               buf->size = total;
 138               char *wp = buf->msg;
 139               for (int cnt = 0; cnt < nlist; ++cnt)
 140                 wp = mempcpy (wp, iov[cnt].iov_base, iov[cnt].iov_len);
 141               *wp = '\0';
 142
 143               /* We have to free the old buffer since the application might
 144                  catch the SIGABRT signal.  */
 145               struct abort_msg_s *old = atomic_exchange_acq (&__abort_msg,
 146                                                              buf);
 147               if (old != NULL)
 148                 __munmap (old, old->size);
 149             }
 150         }
 151     }
 152
 153   va_end (ap);
 154
 155   /* If we  had no success writing the message, use syslog.  */
 156   if (! written)
 157     vsyslog (LOG_ERR, fmt, ap_copy);
 158
 159   va_end (ap_copy);
 160
 161   if (do_abort)
 162     /* Kill the application.  */
 163     abort ();
 164 }
 165
 166
 167 void
 168 __libc_fatal (message)
 169      const char *message;
 170 {
 171   /* The loop is added only to keep gcc happy.  */
 172   while (1)
 173     __libc_message (1, "%s", message);
 174 }
 175 libc_hidden_def (__libc_fatal)