1 /* Error handler for noninteractive utilities
2 Copyright (C) 1990-2023 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 <https://www.gnu.org/licenses/>. */
18
19 /* Written by David MacKenzie <djm@gnu.ai.mit.edu>. */
20
21 #if !_LIBC
22 # include <config.h>
23 #endif
24
25 #include "error.h"
26
27 #include <stdarg.h>
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <string.h>
31
32 #if !_LIBC && ENABLE_NLS
33 # include "gettext.h"
34 # define _(msgid) gettext (msgid)
35 #endif
36
37 #ifdef _LIBC
38 # include <libintl.h>
39 # include <stdbool.h>
40 # include <stdint.h>
41 # include <wchar.h>
42 # define mbsrtowcs __mbsrtowcs
43 # define USE_UNLOCKED_IO 0
44 # define _GL_ATTRIBUTE_FORMAT_PRINTF(a, b)
45 # define _GL_ARG_NONNULL(a)
46 #endif
47
48 #if USE_UNLOCKED_IO
49 # include "unlocked-io.h"
50 #endif
51
52 #ifndef _
53 # define _(String) String
54 #endif
55
56 /* If NULL, error will flush stdout, then print on stderr the program
57 name, a colon and a space. Otherwise, error will call this
58 function without parameters instead. */
59 void (*error_print_progname) (void);
60
61 /* This variable is incremented each time 'error' is called. */
62 unsigned int error_message_count;
63
64 #ifdef _LIBC
65 /* In the GNU C library, there is a predefined variable for this. */
66
67 # define program_name program_invocation_name
68 # include <errno.h>
69 # include <limits.h>
70 # include <libio/libioP.h>
71
72 /* In GNU libc we want do not want to use the common name 'error' directly.
73 Instead make it a weak alias. */
74 extern void __error (int status, int errnum, const char *message, ...)
75 __attribute__ ((__format__ (__printf__, 3, 4)));
76 extern void __error_at_line (int status, int errnum, const char *file_name,
77 unsigned int line_number, const char *message,
78 ...)
79 __attribute__ ((__format__ (__printf__, 5, 6)));;
80 # define error __error
81 # define error_at_line __error_at_line
82
83 # include <libio/iolibio.h>
84 # define fflush(s) _IO_fflush (s)
85 # undef putc
86 # define putc(c, fp) _IO_putc (c, fp)
87
88 # include <libc-lock.h>
89
90 #else /* not _LIBC */
91
92 # include <fcntl.h>
93 # include <unistd.h>
94
95 # if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
96 /* Get declarations of the native Windows API functions. */
97 # define WIN32_LEAN_AND_MEAN
98 # include <windows.h>
99 /* Get _get_osfhandle. */
100 # include "msvc-nothrow.h"
101 # endif
102
103 /* The gnulib override of fcntl is not needed in this file. */
104 # undef fcntl
105
106 # if !HAVE_DECL_STRERROR_R
107 # ifndef HAVE_DECL_STRERROR_R
108 "this configure-time declaration test was not run"
109 # endif
110 # if STRERROR_R_CHAR_P
111 char *strerror_r ();
112 # else
113 int strerror_r ();
114 # endif
115 # endif
116
117 /* The calling program should define program_name and set it to the
118 name of the executing program. */
119 extern char *program_name;
120
121 # if HAVE_STRERROR_R || defined strerror_r
122 # define __strerror_r strerror_r
123 # endif /* HAVE_STRERROR_R || defined strerror_r */
124 #endif /* not _LIBC */
125
126 #if !_LIBC
127 /* Return non-zero if FD is open. */
128 static int
129 is_open (int fd)
130 {
131 # if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
132 /* On native Windows: The initial state of unassigned standard file
133 descriptors is that they are open but point to an INVALID_HANDLE_VALUE.
134 There is no fcntl, and the gnulib replacement fcntl does not support
135 F_GETFL. */
136 return (HANDLE) _get_osfhandle (fd) != INVALID_HANDLE_VALUE;
137 # else
138 # ifndef F_GETFL
139 # error Please port fcntl to your platform
140 # endif
141 return 0 <= fcntl (fd, F_GETFL);
142 # endif
143 }
144 #endif
145
146 static void
147 flush_stdout (void)
148 {
149 #if !_LIBC
150 int stdout_fd;
151
152 # if GNULIB_FREOPEN_SAFER
153 /* Use of gnulib's freopen-safer module normally ensures that
154 fileno (stdout) == 1
155 whenever stdout is open. */
156 stdout_fd = STDOUT_FILENO;
157 # else
158 /* POSIX states that fileno (stdout) after fclose is unspecified. But in
159 practice it is not a problem, because stdout is statically allocated and
160 the fd of a FILE stream is stored as a field in its allocated memory. */
161 stdout_fd = fileno (stdout);
162 # endif
163 /* POSIX states that fflush (stdout) after fclose is unspecified; it
164 is safe in glibc, but not on all other platforms. fflush (NULL)
165 is always defined, but too draconian. */
166 if (0 <= stdout_fd && is_open (stdout_fd))
167 #endif
168 fflush (stdout);
169 }
170
171 static void
172 print_errno_message (int errnum)
173 {
174 char const *s;
175
176 #if defined HAVE_STRERROR_R || _LIBC
177 char errbuf[1024];
178 # if _LIBC || STRERROR_R_CHAR_P
179 s = __strerror_r (errnum, errbuf, sizeof errbuf);
180 # else
181 if (__strerror_r (errnum, errbuf, sizeof errbuf) == 0)
182 s = errbuf;
183 else
184 s = 0;
185 # endif
186 #else
187 s = strerror (errnum);
188 #endif
189
190 #if !_LIBC
191 if (! s)
192 s = _("Unknown system error");
193 #endif
194
195 #if _LIBC
196 __fxprintf (NULL, ": %s", s);
197 #else
198 fprintf (stderr, ": %s", s);
199 #endif
200 }
201
202 static void _GL_ATTRIBUTE_FORMAT_PRINTF (3, 0) _GL_ARG_NONNULL ((3))
203 error_tail (int status, int errnum, const char *message, va_list args,
204 unsigned int mode_flags)
205 {
206 #if _LIBC
207 int ret = __vfxprintf (stderr, message, args, mode_flags);
208 if (ret < 0 && errno == ENOMEM && _IO_fwide (stderr, 0) > 0)
209 /* Leave a trace in case the heap allocation of the message string
210 failed. */
211 fputws_unlocked (L"out of memory\n", stderr);
212 #else
213 vfprintf (stderr, message, args);
214 #endif
215 va_end (args);
216
217 ++error_message_count;
218 if (errnum)
219 print_errno_message (errnum);
220 #if _LIBC
221 __fxprintf (NULL, "\n");
222 #else
223 putc ('\n', stderr);
224 #endif
225 fflush (stderr);
226 if (status)
227 exit (status);
228 }
229
230
231 /* Print the program name and error message MESSAGE, which is a printf-style
232 format string with optional args.
233 If ERRNUM is nonzero, print its corresponding system error message.
234 Exit with status STATUS if it is nonzero. */
235 void
236 __error_internal (int status, int errnum, const char *message,
237 va_list args, unsigned int mode_flags)
238 {
239 #if defined _LIBC
240 /* We do not want this call to be cut short by a thread
241 cancellation. Therefore disable cancellation for now. */
242 int state = PTHREAD_CANCEL_ENABLE;
243 __pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &state);
244 #endif
245
246 flush_stdout ();
247 #ifdef _LIBC
248 _IO_flockfile (stderr);
249 #endif
250 if (error_print_progname)
251 (*error_print_progname) ();
252 else
253 {
254 #if _LIBC
255 __fxprintf (NULL, "%s: ", program_name);
256 #else
257 fprintf (stderr, "%s: ", program_name);
258 #endif
259 }
260
261 error_tail (status, errnum, message, args, mode_flags);
262
263 #ifdef _LIBC
264 _IO_funlockfile (stderr);
265 __pthread_setcancelstate (state, NULL);
266 #endif
267 }
268
269 void
270 error (int status, int errnum, const char *message, ...)
271 {
272 va_list ap;
273 va_start (ap, message);
274 __error_internal (status, errnum, message, ap, 0);
275 va_end (ap);
276 }
277
278 /* Sometimes we want to have at most one error per line. This
279 variable controls whether this mode is selected or not. */
280 int error_one_per_line;
281
282 void
283 __error_at_line_internal (int status, int errnum, const char *file_name,
284 unsigned int line_number, const char *message,
285 va_list args, unsigned int mode_flags)
286 {
287 if (error_one_per_line)
288 {
289 static const char *old_file_name;
290 static unsigned int old_line_number;
291
292 if (old_line_number == line_number
293 && (file_name == old_file_name
294 || (old_file_name != NULL
295 && file_name != NULL
296 && strcmp (old_file_name, file_name) == 0)))
297
298 /* Simply return and print nothing. */
299 return;
300
301 old_file_name = file_name;
302 old_line_number = line_number;
303 }
304
305 #if defined _LIBC
306 /* We do not want this call to be cut short by a thread
307 cancellation. Therefore disable cancellation for now. */
308 int state = PTHREAD_CANCEL_ENABLE;
309 __pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &state);
310 #endif
311
312 flush_stdout ();
313 #ifdef _LIBC
314 _IO_flockfile (stderr);
315 #endif
316 if (error_print_progname)
317 (*error_print_progname) ();
318 else
319 {
320 #if _LIBC
321 __fxprintf (NULL, "%s:", program_name);
322 #else
323 fprintf (stderr, "%s:", program_name);
324 #endif
325 }
326
327 #if _LIBC
328 __fxprintf (NULL, file_name != NULL ? "%s:%d: " : " ",
329 file_name, line_number);
330 #else
331 fprintf (stderr, file_name != NULL ? "%s:%d: " : " ",
332 file_name, line_number);
333 #endif
334
335 error_tail (status, errnum, message, args, mode_flags);
336
337 #ifdef _LIBC
338 _IO_funlockfile (stderr);
339 __pthread_setcancelstate (state, NULL);
340 #endif
341 }
342
343 void
344 error_at_line (int status, int errnum, const char *file_name,
345 unsigned int line_number, const char *message, ...)
346 {
347 va_list ap;
348 va_start (ap, message);
349 __error_at_line_internal (status, errnum, file_name, line_number,
350 message, ap, 0);
351 va_end (ap);
352 }
353
354 #ifdef _LIBC
355 /* Make the weak alias. */
356 # undef error
357 # undef error_at_line
358 weak_alias (__error, error)
359 weak_alias (__error_at_line, error_at_line)
360 #endif