sysdeps/unix/sysv/linux/libc_fatal.c

   1 /* Copyright (C) 1993-1995,1997,2000,2002-2005 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, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <errno.h>
  20 #include <fcntl.h>
  21 #include <paths.h>
  22 #include <stdarg.h>
  23 #include <stdbool.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <sysdep.h>
  28 #include <unistd.h>
  29 #include <sys/syslog.h>
  30 #include <execinfo.h>
  31
  32 /* Abort with an error message.  */
  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 = (void *) list->str;
 120           iov[cnt].iov_len = list->len;
 121           total += list->len;
 122           list = list->next;
 123         }
 124
 125       INTERNAL_SYSCALL_DECL (err);
 126       ssize_t cnt;
 127       do
 128         cnt = INTERNAL_SYSCALL (writev, err, 3, fd, iov, nlist);
 129       while (INTERNAL_SYSCALL_ERROR_P (cnt, err)
 130              && INTERNAL_SYSCALL_ERRNO (cnt, err) == EINTR);
 131
 132       if (cnt == total)
 133         written = true;
 134     }
 135
 136   va_end (ap);
 137
 138   /* If we  had no success writing the message, use syslog.  */
 139   if (! written)
 140     vsyslog (LOG_ERR, fmt, ap_copy);
 141
 142   va_end (ap_copy);
 143
 144   if (do_abort)
 145     {
 146       if (do_abort > 1 && written)
 147         {
 148           void *addrs[64];
 149 #define naddrs (sizeof (addrs) / sizeof (addrs[0]))
 150           int n = __backtrace (addrs, naddrs);
 151           if (n > 2)
 152             {
 153 #define strnsize(str) str, strlen (str)
 154 #define writestr(str) write_not_cancel (fd, str)
 155               writestr (strnsize ("======= Backtrace: =========\n"));
 156               __backtrace_symbols_fd (addrs + 1, n - 1, fd);
 157
 158               writestr (strnsize ("======= Memory map: ========\n"));
 159               int fd2 = open_not_cancel_2 ("/proc/self/maps", O_RDONLY);
 160               char buf[1024];
 161               ssize_t n2;
 162               while ((n2 = read_not_cancel (fd2, buf, sizeof (buf))) > 0)
 163                 if (write_not_cancel (fd, buf, n2) != n2)
 164                   break;
 165               close_not_cancel_no_status (fd2);
 166             }
 167         }
 168
 169       /* Terminate the process.  */
 170       abort ();
 171     }
 172 }
 173
 174
 175 void
 176 __libc_fatal (message)
 177      const char *message;
 178 {
 179   /* The loop is added only to keep gcc happy.  */
 180   while (1)
 181     __libc_message (1, "%s", message);
 182 }
 183 libc_hidden_def (__libc_fatal)