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1 /* Error handler for noninteractive utilities
2    Copyright (C) 1990-1998, 2000-2007, 2009-2012 Free Software Foundation, Inc.
3    This file is part of the GNU C Library.
4 
5    This program is free software: you can redistribute it and/or modify
6    it under the terms of the GNU General Public License as published by
7    the Free Software Foundation; either version 3 of the License, or
8    (at your option) any later version.
9 
10    This program 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
13    GNU General Public License for more details.
14 
15    You should have received a copy of the GNU General Public License
16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
17 
18 /* Written by David MacKenzie <djm@gnu.ai.mit.edu>.  */
19 
20 #if !_LIBC
21 # include <config.h>
22 #endif
23 
24 #include "error.h"
25 
26 #include <stdarg.h>
27 #include <stdio.h>
28 #include <stdlib.h>
29 #include <string.h>
30 
31 #if !_LIBC && ENABLE_NLS
32 # include "gettext.h"
33 # define _(msgid) gettext (msgid)
34 #endif
35 
36 #ifdef _LIBC
37 # include <libintl.h>
38 # include <stdbool.h>
39 # include <stdint.h>
40 # include <wchar.h>
41 # define mbsrtowcs __mbsrtowcs
42 #endif
43 
44 #if USE_UNLOCKED_IO
45 # include "unlocked-io.h"
46 #endif
47 
48 #ifndef _
49 # define _(String) String
50 #endif
51 
52 /* If NULL, error will flush stdout, then print on stderr the program
53    name, a colon and a space.  Otherwise, error will call this
54    function without parameters instead.  */
55 void (*error_print_progname) (void);
56 
57 /* This variable is incremented each time 'error' is called.  */
58 unsigned int error_message_count;
59 
60 #ifdef _LIBC
61 /* In the GNU C library, there is a predefined variable for this.  */
62 
63 # define program_name program_invocation_name
64 # include <errno.h>
65 # include <limits.h>
66 # include <libio/libioP.h>
67 
68 /* In GNU libc we want do not want to use the common name 'error' directly.
69    Instead make it a weak alias.  */
70 extern void __error (int status, int errnum, const char *message, ...)
71      __attribute__ ((__format__ (__printf__, 3, 4)));
72 extern void __error_at_line (int status, int errnum, const char *file_name,
73                              unsigned int line_number, const char *message,
74                              ...)
75      __attribute__ ((__format__ (__printf__, 5, 6)));;
76 # define error __error
77 # define error_at_line __error_at_line
78 
79 # include <libio/iolibio.h>
80 # define fflush(s) INTUSE(_IO_fflush) (s)
81 # undef putc
82 # define putc(c, fp) INTUSE(_IO_putc) (c, fp)
83 
84 # include <bits/libc-lock.h>
85 
86 #else /* not _LIBC */
87 
88 # include <fcntl.h>
89 # include <unistd.h>
90 
91 # if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
92 /* Get declarations of the native Windows API functions.  */
93 #  define WIN32_LEAN_AND_MEAN
94 #  include <windows.h>
95 /* Get _get_osfhandle.  */
96 #  include "msvc-nothrow.h"
97 # endif
98 
99 /* The gnulib override of fcntl is not needed in this file.  */
100 # undef fcntl
101 
102 # if !HAVE_DECL_STRERROR_R
103 #  ifndef HAVE_DECL_STRERROR_R
104 "this configure-time declaration test was not run"
105 #  endif
106 #  if STRERROR_R_CHAR_P
107 char *strerror_r ();
108 #  else
109 int strerror_r ();
110 #  endif
111 # endif
112 
113 /* The calling program should define program_name and set it to the
114    name of the executing program.  */
115 extern char *program_name;
116 
117 # if HAVE_STRERROR_R || defined strerror_r
118 #  define __strerror_r strerror_r
119 # endif /* HAVE_STRERROR_R || defined strerror_r */
120 #endif  /* not _LIBC */
121 
122 #if !_LIBC
123 /* Return non-zero if FD is open.  */
124 static int
is_open(int fd)125 is_open (int fd)
126 {
127 # if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
128   /* On native Windows: The initial state of unassigned standard file
129      descriptors is that they are open but point to an INVALID_HANDLE_VALUE.
130      There is no fcntl, and the gnulib replacement fcntl does not support
131      F_GETFL.  */
132   return (HANDLE) _get_osfhandle (fd) != INVALID_HANDLE_VALUE;
133 # else
134 #  ifndef F_GETFL
135 #   error Please port fcntl to your platform
136 #  endif
137   return 0 <= fcntl (fd, F_GETFL);
138 # endif
139 }
140 #endif
141 
142 static void
flush_stdout(void)143 flush_stdout (void)
144 {
145 #if !_LIBC
146   int stdout_fd;
147 
148 # if GNULIB_FREOPEN_SAFER
149   /* Use of gnulib's freopen-safer module normally ensures that
150        fileno (stdout) == 1
151      whenever stdout is open.  */
152   stdout_fd = STDOUT_FILENO;
153 # else
154   /* POSIX states that fileno (stdout) after fclose is unspecified.  But in
155      practice it is not a problem, because stdout is statically allocated and
156      the fd of a FILE stream is stored as a field in its allocated memory.  */
157   stdout_fd = fileno (stdout);
158 # endif
159   /* POSIX states that fflush (stdout) after fclose is unspecified; it
160      is safe in glibc, but not on all other platforms.  fflush (NULL)
161      is always defined, but too draconian.  */
162   if (0 <= stdout_fd && is_open (stdout_fd))
163 #endif
164     fflush (stdout);
165 }
166 
167 static void
print_errno_message(int errnum)168 print_errno_message (int errnum)
169 {
170   char const *s;
171 
172 #if defined HAVE_STRERROR_R || _LIBC
173   char errbuf[1024];
174 # if STRERROR_R_CHAR_P || _LIBC
175   s = __strerror_r (errnum, errbuf, sizeof errbuf);
176 # else
177   if (__strerror_r (errnum, errbuf, sizeof errbuf) == 0)
178     s = errbuf;
179   else
180     s = 0;
181 # endif
182 #else
183   s = strerror (errnum);
184 #endif
185 
186 #if !_LIBC
187   if (! s)
188     s = _("Unknown system error");
189 #endif
190 
191 #if _LIBC
192   __fxprintf (NULL, ": %s", s);
193 #else
194   fprintf (stderr, ": %s", s);
195 #endif
196 }
197 
198 static void
error_tail(int status,int errnum,const char * message,va_list args)199 error_tail (int status, int errnum, const char *message, va_list args)
200 {
201 #if _LIBC
202   if (_IO_fwide (stderr, 0) > 0)
203     {
204 # define ALLOCA_LIMIT 2000
205       size_t len = strlen (message) + 1;
206       wchar_t *wmessage = NULL;
207       mbstate_t st;
208       size_t res;
209       const char *tmp;
210       bool use_malloc = false;
211 
212       while (1)
213         {
214           if (__libc_use_alloca (len * sizeof (wchar_t)))
215             wmessage = (wchar_t *) alloca (len * sizeof (wchar_t));
216           else
217             {
218               if (!use_malloc)
219                 wmessage = NULL;
220 
221               wchar_t *p = (wchar_t *) realloc (wmessage,
222                                                 len * sizeof (wchar_t));
223               if (p == NULL)
224                 {
225                   free (wmessage);
226                   fputws_unlocked (L"out of memory\n", stderr);
227                   return;
228                 }
229               wmessage = p;
230               use_malloc = true;
231             }
232 
233           memset (&st, '\0', sizeof (st));
234           tmp = message;
235 
236           res = mbsrtowcs (wmessage, &tmp, len, &st);
237           if (res != len)
238             break;
239 
240           if (__builtin_expect (len >= SIZE_MAX / 2, 0))
241             {
242               /* This really should not happen if everything is fine.  */
243               res = (size_t) -1;
244               break;
245             }
246 
247           len *= 2;
248         }
249 
250       if (res == (size_t) -1)
251         {
252           /* The string cannot be converted.  */
253           if (use_malloc)
254             {
255               free (wmessage);
256               use_malloc = false;
257             }
258           wmessage = (wchar_t *) L"???";
259         }
260 
261       __vfwprintf (stderr, wmessage, args);
262 
263       if (use_malloc)
264         free (wmessage);
265     }
266   else
267 #endif
268     vfprintf (stderr, message, args);
269   va_end (args);
270 
271   ++error_message_count;
272   if (errnum)
273     print_errno_message (errnum);
274 #if _LIBC
275   __fxprintf (NULL, "\n");
276 #else
277   putc ('\n', stderr);
278 #endif
279   fflush (stderr);
280   if (status)
281     exit (status);
282 }
283 
284 
285 /* Print the program name and error message MESSAGE, which is a printf-style
286    format string with optional args.
287    If ERRNUM is nonzero, print its corresponding system error message.
288    Exit with status STATUS if it is nonzero.  */
289 void
error(int status,int errnum,const char * message,...)290 error (int status, int errnum, const char *message, ...)
291 {
292   va_list args;
293 
294 #if defined _LIBC && defined __libc_ptf_call
295   /* We do not want this call to be cut short by a thread
296      cancellation.  Therefore disable cancellation for now.  */
297   int state = PTHREAD_CANCEL_ENABLE;
298   __libc_ptf_call (pthread_setcancelstate, (PTHREAD_CANCEL_DISABLE, &state),
299                    0);
300 #endif
301 
302   flush_stdout ();
303 #ifdef _LIBC
304   _IO_flockfile (stderr);
305 #endif
306   if (error_print_progname)
307     (*error_print_progname) ();
308   else
309     {
310 #if _LIBC
311       __fxprintf (NULL, "%s: ", program_name);
312 #else
313       fprintf (stderr, "%s: ", program_name);
314 #endif
315     }
316 
317   va_start (args, message);
318   error_tail (status, errnum, message, args);
319 
320 #ifdef _LIBC
321   _IO_funlockfile (stderr);
322 # ifdef __libc_ptf_call
323   __libc_ptf_call (pthread_setcancelstate, (state, NULL), 0);
324 # endif
325 #endif
326 }
327 
328 /* Sometimes we want to have at most one error per line.  This
329    variable controls whether this mode is selected or not.  */
330 int error_one_per_line;
331 
332 void
error_at_line(int status,int errnum,const char * file_name,unsigned int line_number,const char * message,...)333 error_at_line (int status, int errnum, const char *file_name,
334                unsigned int line_number, const char *message, ...)
335 {
336   va_list args;
337 
338   if (error_one_per_line)
339     {
340       static const char *old_file_name;
341       static unsigned int old_line_number;
342 
343       if (old_line_number == line_number
344           && (file_name == old_file_name
345               || strcmp (old_file_name, file_name) == 0))
346         /* Simply return and print nothing.  */
347         return;
348 
349       old_file_name = file_name;
350       old_line_number = line_number;
351     }
352 
353 #if defined _LIBC && defined __libc_ptf_call
354   /* We do not want this call to be cut short by a thread
355      cancellation.  Therefore disable cancellation for now.  */
356   int state = PTHREAD_CANCEL_ENABLE;
357   __libc_ptf_call (pthread_setcancelstate, (PTHREAD_CANCEL_DISABLE, &state),
358                    0);
359 #endif
360 
361   flush_stdout ();
362 #ifdef _LIBC
363   _IO_flockfile (stderr);
364 #endif
365   if (error_print_progname)
366     (*error_print_progname) ();
367   else
368     {
369 #if _LIBC
370       __fxprintf (NULL, "%s:", program_name);
371 #else
372       fprintf (stderr, "%s:", program_name);
373 #endif
374     }
375 
376 #if _LIBC
377   __fxprintf (NULL, file_name != NULL ? "%s:%d: " : " ",
378               file_name, line_number);
379 #else
380   fprintf (stderr, file_name != NULL ? "%s:%d: " : " ",
381            file_name, line_number);
382 #endif
383 
384   va_start (args, message);
385   error_tail (status, errnum, message, args);
386 
387 #ifdef _LIBC
388   _IO_funlockfile (stderr);
389 # ifdef __libc_ptf_call
390   __libc_ptf_call (pthread_setcancelstate, (state, NULL), 0);
391 # endif
392 #endif
393 }
394 
395 #ifdef _LIBC
396 /* Make the weak alias.  */
397 # undef error
398 # undef error_at_line
399 weak_alias (__error, error)
400 weak_alias (__error_at_line, error_at_line)
401 #endif
402