1/* Catastrophic failure reports. Generic POSIX.1 version.
2 Copyright (C) 1993-2018 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 (enum __libc_message_action action, 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 /* Don't call __libc_secure_getenv if we aren't doing backtrace, which
79 may access the corrupted stack. */
80 if ((action & do_backtrace))
81 {
82 /* Open a descriptor for /dev/tty unless the user explicitly
83 requests errors on standard error. */
84 const char *on_2 = __libc_secure_getenv ("LIBC_FATAL_STDERR_");
85 if (on_2 == NULL || *on_2 == '\0')
86 fd = __open_nocancel (_PATH_TTY, O_RDWR | O_NOCTTY | O_NDELAY);
87 }
88
89 if (fd == -1)
90 fd = STDERR_FILENO;
91
92 struct str_list *list = NULL;
93 int nlist = 0;
94
95 const char *cp = fmt;
96 while (*cp != '\0')
97 {
98 /* Find the next "%s" or the end of the string. */
99 const char *next = cp;
100 while (next[0] != '%' || next[1] != 's')
101 {
102 next = __strchrnul (next + 1, '%');
103
104 if (next[0] == '\0')
105 break;
106 }
107
108 /* Determine what to print. */
109 const char *str;
110 size_t len;
111 if (cp[0] == '%' && cp[1] == 's')
112 {
113 str = va_arg (ap, const char *);
114 len = strlen (str);
115 cp += 2;
116 }
117 else
118 {
119 str = cp;
120 len = next - cp;
121 cp = next;
122 }
123
124 struct str_list *newp = alloca (sizeof (struct str_list));
125 newp->str = str;
126 newp->len = len;
127 newp->next = list;
128 list = newp;
129 ++nlist;
130 }
131
132 bool written = false;
133 if (nlist > 0)
134 {
135 struct iovec *iov = alloca (nlist * sizeof (struct iovec));
136 ssize_t total = 0;
137
138 for (int cnt = nlist - 1; cnt >= 0; --cnt)
139 {
140 iov[cnt].iov_base = (char *) list->str;
141 iov[cnt].iov_len = list->len;
142 total += list->len;
143 list = list->next;
144 }
145
146 written = WRITEV_FOR_FATAL (fd, iov, nlist, total);
147
148 if ((action & do_abort))
149 {
150 total = ((total + 1 + GLRO(dl_pagesize) - 1)
151 & ~(GLRO(dl_pagesize) - 1));
152 struct abort_msg_s *buf = __mmap (NULL, total,
153 PROT_READ | PROT_WRITE,
154 MAP_ANON | MAP_PRIVATE, -1, 0);
155 if (__glibc_likely (buf != MAP_FAILED))
156 {
157 buf->size = total;
158 char *wp = buf->msg;
159 for (int cnt = 0; cnt < nlist; ++cnt)
160 wp = mempcpy (wp, iov[cnt].iov_base, iov[cnt].iov_len);
161 *wp = '\0';
162
163 /* We have to free the old buffer since the application might
164 catch the SIGABRT signal. */
165 struct abort_msg_s *old = atomic_exchange_acq (&__abort_msg,
166 buf);
167 if (old != NULL)
168 __munmap (old, old->size);
169 }
170 }
171 }
172
173 va_end (ap);
174
175 if ((action & do_abort))
176 {
177 if ((action & do_backtrace))
178 BEFORE_ABORT (do_abort, written, fd);
179
180 /* Kill the application. */
181 abort ();
182 }
183}
184
185
186void
187__libc_fatal (const char *message)
188{
189 /* The loop is added only to keep gcc happy. */
190 while (1)
191 __libc_message (do_abort | do_backtrace, "%s", message);
192}
193libc_hidden_def (__libc_fatal)
194