1/* Catastrophic failure reports. Generic POSIX.1 version.
2 Copyright (C) 1993-2016 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/mman.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#ifndef WRITEV_FOR_FATAL
40# define WRITEV_FOR_FATAL writev_for_fatal
41static bool
42writev_for_fatal (int fd, const struct iovec *iov, size_t niov, size_t total)
43{
44 return TEMP_FAILURE_RETRY (__writev (fd, iov, niov)) == total;
45}
46#endif
47
48#ifndef BEFORE_ABORT
49# define BEFORE_ABORT before_abort
50static void
51before_abort (int do_abort __attribute__ ((unused)),
52 bool written __attribute__ ((unused)),
53 int fd __attribute__ ((unused)))
54{
55}
56#endif
57
58struct str_list
59{
60 const char *str;
61 size_t len;
62 struct str_list *next;
63};
64
65/* Abort with an error message. */
66void
67__libc_message (int do_abort, const char *fmt, ...)
68{
69 va_list ap;
70 int fd = -1;
71
72 va_start (ap, fmt);
73
74#ifdef FATAL_PREPARE
75 FATAL_PREPARE;
76#endif
77
78 /* Open a descriptor for /dev/tty unless the user explicitly
79 requests errors on standard error. */
80 const char *on_2 = __libc_secure_getenv ("LIBC_FATAL_STDERR_");
81 if (on_2 == NULL || *on_2 == '\0')
82 fd = open_not_cancel_2 (_PATH_TTY, O_RDWR | O_NOCTTY | O_NDELAY);
83
84 if (fd == -1)
85 fd = STDERR_FILENO;
86
87 struct str_list *list = NULL;
88 int nlist = 0;
89
90 const char *cp = fmt;
91 while (*cp != '\0')
92 {
93 /* Find the next "%s" or the end of the string. */
94 const char *next = cp;
95 while (next[0] != '%' || next[1] != 's')
96 {
97 next = __strchrnul (next + 1, '%');
98
99 if (next[0] == '\0')
100 break;
101 }
102
103 /* Determine what to print. */
104 const char *str;
105 size_t len;
106 if (cp[0] == '%' && cp[1] == 's')
107 {
108 str = va_arg (ap, const char *);
109 len = strlen (str);
110 cp += 2;
111 }
112 else
113 {
114 str = cp;
115 len = next - cp;
116 cp = next;
117 }
118
119 struct str_list *newp = alloca (sizeof (struct str_list));
120 newp->str = str;
121 newp->len = len;
122 newp->next = list;
123 list = newp;
124 ++nlist;
125 }
126
127 bool written = false;
128 if (nlist > 0)
129 {
130 struct iovec *iov = alloca (nlist * sizeof (struct iovec));
131 ssize_t total = 0;
132
133 for (int cnt = nlist - 1; cnt >= 0; --cnt)
134 {
135 iov[cnt].iov_base = (char *) list->str;
136 iov[cnt].iov_len = list->len;
137 total += list->len;
138 list = list->next;
139 }
140
141 written = WRITEV_FOR_FATAL (fd, iov, nlist, total);
142
143 if (do_abort)
144 {
145 total = ((total + 1 + GLRO(dl_pagesize) - 1)
146 & ~(GLRO(dl_pagesize) - 1));
147 struct abort_msg_s *buf = __mmap (NULL, total,
148 PROT_READ | PROT_WRITE,
149 MAP_ANON | MAP_PRIVATE, -1, 0);
150 if (__glibc_likely (buf != MAP_FAILED))
151 {
152 buf->size = total;
153 char *wp = buf->msg;
154 for (int cnt = 0; cnt < nlist; ++cnt)
155 wp = mempcpy (wp, iov[cnt].iov_base, iov[cnt].iov_len);
156 *wp = '\0';
157
158 /* We have to free the old buffer since the application might
159 catch the SIGABRT signal. */
160 struct abort_msg_s *old = atomic_exchange_acq (&__abort_msg,
161 buf);
162 if (old != NULL)
163 __munmap (old, old->size);
164 }
165 }
166 }
167
168 va_end (ap);
169
170 if (do_abort)
171 {
172 BEFORE_ABORT (do_abort, written, fd);
173
174 /* Kill the application. */
175 abort ();
176 }
177}
178
179
180void
181__libc_fatal (const char *message)
182{
183 /* The loop is added only to keep gcc happy. */
184 while (1)
185 __libc_message (1, "%s", message);
186}
187libc_hidden_def (__libc_fatal)
188