1/* Error handler for noninteractive utilities
2   Copyright (C) 1990-1998, 2000-2007, 2009-2020 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 <https://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# define USE_UNLOCKED_IO 0
43# define _GL_ATTRIBUTE_FORMAT_PRINTF(a, b)
44# define _GL_ARG_NONNULL(a)
45#else
46# include "getprogname.h"
47#endif
48
49#if USE_UNLOCKED_IO
50# include "unlocked-io.h"
51#endif
52
53#ifndef _
54# define _(String) String
55#endif
56
57/* If NULL, error will flush stdout, then print on stderr the program
58   name, a colon and a space.  Otherwise, error will call this
59   function without parameters instead.  */
60void (*error_print_progname) (void);
61
62/* This variable is incremented each time 'error' is called.  */
63unsigned int error_message_count;
64
65#ifdef _LIBC
66/* In the GNU C library, there is a predefined variable for this.  */
67
68# define program_name program_invocation_name
69# include <errno.h>
70# include <limits.h>
71# include <libio/libioP.h>
72
73/* In GNU libc we want do not want to use the common name 'error' directly.
74   Instead make it a weak alias.  */
75extern void __error (int status, int errnum, const char *message, ...)
76     __attribute__ ((__format__ (__printf__, 3, 4)));
77extern void __error_at_line (int status, int errnum, const char *file_name,
78                             unsigned int line_number, const char *message,
79                             ...)
80     __attribute__ ((__format__ (__printf__, 5, 6)));
81# define error __error
82# define error_at_line __error_at_line
83
84# include <libio/iolibio.h>
85# define fflush(s) _IO_fflush (s)
86# undef putc
87# define putc(c, fp) _IO_putc (c, fp)
88
89# include <bits/libc-lock.h>
90
91#else /* not _LIBC */
92
93# include <fcntl.h>
94# include <unistd.h>
95
96# if defined _WIN32 && ! defined __CYGWIN__
97/* Get declarations of the native Windows API functions.  */
98#  define WIN32_LEAN_AND_MEAN
99#  include <windows.h>
100/* Get _get_osfhandle.  */
101#  if GNULIB_MSVC_NOTHROW
102#   include "msvc-nothrow.h"
103#  else
104#   include <io.h>
105#  endif
106# endif
107
108/* The gnulib override of fcntl is not needed in this file.  */
109# undef fcntl
110
111# if !(GNULIB_STRERROR_R_POSIX || HAVE_DECL_STRERROR_R)
112#  ifndef HAVE_DECL_STRERROR_R
113"this configure-time declaration test was not run"
114#  endif
115#  if STRERROR_R_CHAR_P
116char *strerror_r (int errnum, char *buf, size_t buflen);
117#  else
118int strerror_r (int errnum, char *buf, size_t buflen);
119#  endif
120# endif
121
122# define program_name getprogname ()
123
124# if GNULIB_STRERROR_R_POSIX || HAVE_STRERROR_R || defined strerror_r
125#  define __strerror_r strerror_r
126# endif /* GNULIB_STRERROR_R_POSIX || HAVE_STRERROR_R || defined strerror_r */
127#endif  /* not _LIBC */
128
129#if !_LIBC
130/* Return non-zero if FD is open.  */
131static int
132is_open (int fd)
133{
134# if defined _WIN32 && ! defined __CYGWIN__
135  /* On native Windows: The initial state of unassigned standard file
136     descriptors is that they are open but point to an INVALID_HANDLE_VALUE.
137     There is no fcntl, and the gnulib replacement fcntl does not support
138     F_GETFL.  */
139  return (HANDLE) _get_osfhandle (fd) != INVALID_HANDLE_VALUE;
140# else
141#  ifndef F_GETFL
142#   error Please port fcntl to your platform
143#  endif
144  return 0 <= fcntl (fd, F_GETFL);
145# endif
146}
147#endif
148
149static void
150flush_stdout (void)
151{
152#if !_LIBC
153  int stdout_fd;
154
155# if GNULIB_FREOPEN_SAFER
156  /* Use of gnulib's freopen-safer module normally ensures that
157       fileno (stdout) == 1
158     whenever stdout is open.  */
159  stdout_fd = STDOUT_FILENO;
160# else
161  /* POSIX states that fileno (stdout) after fclose is unspecified.  But in
162     practice it is not a problem, because stdout is statically allocated and
163     the fd of a FILE stream is stored as a field in its allocated memory.  */
164  stdout_fd = fileno (stdout);
165# endif
166  /* POSIX states that fflush (stdout) after fclose is unspecified; it
167     is safe in glibc, but not on all other platforms.  fflush (NULL)
168     is always defined, but too draconian.  */
169  if (0 <= stdout_fd && is_open (stdout_fd))
170#endif
171    fflush (stdout);
172}
173
174static void
175print_errno_message (int errnum)
176{
177  char const *s;
178
179#if _LIBC || GNULIB_STRERROR_R_POSIX || defined HAVE_STRERROR_R
180  char errbuf[1024];
181# if _LIBC || (!GNULIB_STRERROR_R_POSIX && STRERROR_R_CHAR_P)
182  s = __strerror_r (errnum, errbuf, sizeof errbuf);
183# else
184  if (__strerror_r (errnum, errbuf, sizeof errbuf) == 0)
185    s = errbuf;
186  else
187    s = 0;
188# endif
189#else
190  s = strerror (errnum);
191#endif
192
193#if !_LIBC
194  if (! s)
195    s = _("Unknown system error");
196#endif
197
198#if _LIBC
199  __fxprintf (NULL, ": %s", s);
200#else
201  fprintf (stderr, ": %s", s);
202#endif
203}
204
205static void _GL_ATTRIBUTE_FORMAT_PRINTF (3, 0) _GL_ARG_NONNULL ((3))
206error_tail (int status, int errnum, const char *message, va_list args)
207{
208#if _LIBC
209  if (_IO_fwide (stderr, 0) > 0)
210    {
211      size_t len = strlen (message) + 1;
212      wchar_t *wmessage = NULL;
213      mbstate_t st;
214      size_t res;
215      const char *tmp;
216      bool use_malloc = false;
217
218      while (1)
219        {
220          if (__libc_use_alloca (len * sizeof (wchar_t)))
221            wmessage = (wchar_t *) alloca (len * sizeof (wchar_t));
222          else
223            {
224              if (!use_malloc)
225                wmessage = NULL;
226
227              wchar_t *p = (wchar_t *) realloc (wmessage,
228                                                len * sizeof (wchar_t));
229              if (p == NULL)
230                {
231                  free (wmessage);
232                  fputws_unlocked (L"out of memory\n", stderr);
233                  return;
234                }
235              wmessage = p;
236              use_malloc = true;
237            }
238
239          memset (&st, '\0', sizeof (st));
240          tmp = message;
241
242          res = mbsrtowcs (wmessage, &tmp, len, &st);
243          if (res != len)
244            break;
245
246          if (__builtin_expect (len >= SIZE_MAX / sizeof (wchar_t) / 2, 0))
247            {
248              /* This really should not happen if everything is fine.  */
249              res = (size_t) -1;
250              break;
251            }
252
253          len *= 2;
254        }
255
256      if (res == (size_t) -1)
257        {
258          /* The string cannot be converted.  */
259          if (use_malloc)
260            {
261              free (wmessage);
262              use_malloc = false;
263            }
264          wmessage = (wchar_t *) L"???";
265        }
266
267      __vfwprintf (stderr, wmessage, args);
268
269      if (use_malloc)
270        free (wmessage);
271    }
272  else
273#endif
274    vfprintf (stderr, message, args);
275
276  ++error_message_count;
277  if (errnum)
278    print_errno_message (errnum);
279#if _LIBC
280  __fxprintf (NULL, "\n");
281#else
282  putc ('\n', stderr);
283#endif
284  fflush (stderr);
285  if (status)
286    exit (status);
287}
288
289
290/* Print the program name and error message MESSAGE, which is a printf-style
291   format string with optional args.
292   If ERRNUM is nonzero, print its corresponding system error message.
293   Exit with status STATUS if it is nonzero.  */
294void
295error (int status, int errnum, const char *message, ...)
296{
297  va_list args;
298
299#if defined _LIBC && defined __libc_ptf_call
300  /* We do not want this call to be cut short by a thread
301     cancellation.  Therefore disable cancellation for now.  */
302  int state = PTHREAD_CANCEL_ENABLE;
303  __libc_ptf_call (pthread_setcancelstate, (PTHREAD_CANCEL_DISABLE, &state),
304                   0);
305#endif
306
307  flush_stdout ();
308#ifdef _LIBC
309  _IO_flockfile (stderr);
310#endif
311  if (error_print_progname)
312    (*error_print_progname) ();
313  else
314    {
315#if _LIBC
316      __fxprintf (NULL, "%s: ", program_name);
317#else
318      fprintf (stderr, "%s: ", program_name);
319#endif
320    }
321
322  va_start (args, message);
323  error_tail (status, errnum, message, args);
324  va_end (args);
325
326#ifdef _LIBC
327  _IO_funlockfile (stderr);
328# ifdef __libc_ptf_call
329  __libc_ptf_call (pthread_setcancelstate, (state, NULL), 0);
330# endif
331#endif
332}
333
334/* Sometimes we want to have at most one error per line.  This
335   variable controls whether this mode is selected or not.  */
336int error_one_per_line;
337
338void
339error_at_line (int status, int errnum, const char *file_name,
340               unsigned int line_number, const char *message, ...)
341{
342  va_list args;
343
344  if (error_one_per_line)
345    {
346      static const char *old_file_name;
347      static unsigned int old_line_number;
348
349      if (old_line_number == line_number
350          && (file_name == old_file_name
351              || (old_file_name != NULL
352                  && file_name != NULL
353                  && strcmp (old_file_name, file_name) == 0)))
354
355        /* Simply return and print nothing.  */
356        return;
357
358      old_file_name = file_name;
359      old_line_number = line_number;
360    }
361
362#if defined _LIBC && defined __libc_ptf_call
363  /* We do not want this call to be cut short by a thread
364     cancellation.  Therefore disable cancellation for now.  */
365  int state = PTHREAD_CANCEL_ENABLE;
366  __libc_ptf_call (pthread_setcancelstate, (PTHREAD_CANCEL_DISABLE, &state),
367                   0);
368#endif
369
370  flush_stdout ();
371#ifdef _LIBC
372  _IO_flockfile (stderr);
373#endif
374  if (error_print_progname)
375    (*error_print_progname) ();
376  else
377    {
378#if _LIBC
379      __fxprintf (NULL, "%s:", program_name);
380#else
381      fprintf (stderr, "%s:", program_name);
382#endif
383    }
384
385#if _LIBC
386  __fxprintf (NULL, file_name != NULL ? "%s:%u: " : " ",
387              file_name, line_number);
388#else
389  fprintf (stderr, file_name != NULL ? "%s:%u: " : " ",
390           file_name, line_number);
391#endif
392
393  va_start (args, message);
394  error_tail (status, errnum, message, args);
395  va_end (args);
396
397#ifdef _LIBC
398  _IO_funlockfile (stderr);
399# ifdef __libc_ptf_call
400  __libc_ptf_call (pthread_setcancelstate, (state, NULL), 0);
401# endif
402#endif
403}
404
405#ifdef _LIBC
406/* Make the weak alias.  */
407# undef error
408# undef error_at_line
409weak_alias (__error, error)
410weak_alias (__error_at_line, error_at_line)
411#endif
412