lib/error.c

   1 /* Error handler for noninteractive utilities
   2    Copyright (C) 1990-1998, 2000-2007, 2009-2024 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    This file is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU Lesser General Public License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    License, or (at your option) any later version.
   9
  10    This file 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 Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser 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 # define _GL_NO_INLINE_ERROR
  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_STANDARD(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 <bits/libc-lock.h>
  89
  90 #else /* not _LIBC */
  91
  92 # include <fcntl.h>
  93 # include <unistd.h>
  94
  95 # if 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 #  if GNULIB_MSVC_NOTHROW
 101 #   include "msvc-nothrow.h"
 102 #  else
 103 #   include <io.h>
 104 #  endif
 105 # endif
 106
 107 /* The gnulib override of fcntl is not needed in this file.  */
 108 # undef fcntl
 109
 110 # if !(GNULIB_STRERROR_R_POSIX || HAVE_DECL_STRERROR_R)
 111 #  ifndef HAVE_DECL_STRERROR_R
 112 "this configure-time declaration test was not run"
 113 #  endif
 114 #  if STRERROR_R_CHAR_P
 115 char *strerror_r (int errnum, char *buf, size_t buflen);
 116 #  else
 117 int strerror_r (int errnum, char *buf, size_t buflen);
 118 #  endif
 119 # endif
 120
 121 # define program_name getprogname ()
 122
 123 # if GNULIB_STRERROR_R_POSIX || HAVE_STRERROR_R || defined strerror_r
 124 #  define __strerror_r strerror_r
 125 # endif /* GNULIB_STRERROR_R_POSIX || HAVE_STRERROR_R || defined strerror_r */
 126 #endif  /* not _LIBC */
 127
 128 #if !_LIBC
 129 /* Return non-zero if FD is open.  */
 130 static int
 131 is_open (int fd)
 132 {
 133 # if defined _WIN32 && ! defined __CYGWIN__
 134   /* On native Windows: The initial state of unassigned standard file
 135      descriptors is that they are open but point to an INVALID_HANDLE_VALUE.
 136      There is no fcntl, and the gnulib replacement fcntl does not support
 137      F_GETFL.  */
 138   return (HANDLE) _get_osfhandle (fd) != INVALID_HANDLE_VALUE;
 139 # else
 140 #  ifndef F_GETFL
 141 #   error Please port fcntl to your platform
 142 #  endif
 143   return 0 <= fcntl (fd, F_GETFL);
 144 # endif
 145 }
 146 #endif
 147
 148 static void
 149 flush_stdout (void)
 150 {
 151 #if !_LIBC
 152   int stdout_fd;
 153
 154 # if GNULIB_FREOPEN_SAFER
 155   /* Use of gnulib's freopen-safer module normally ensures that
 156        fileno (stdout) == 1
 157      whenever stdout is open.  */
 158   stdout_fd = STDOUT_FILENO;
 159 # else
 160   /* POSIX states that fileno (stdout) after fclose is unspecified.  But in
 161      practice it is not a problem, because stdout is statically allocated and
 162      the fd of a FILE stream is stored as a field in its allocated memory.  */
 163   stdout_fd = fileno (stdout);
 164 # endif
 165   /* POSIX states that fflush (stdout) after fclose is unspecified; it
 166      is safe in glibc, but not on all other platforms.  fflush (NULL)
 167      is always defined, but too draconian.  */
 168   if (0 <= stdout_fd && is_open (stdout_fd))
 169 #endif
 170     fflush (stdout);
 171 }
 172
 173 static void
 174 print_errno_message (int errnum)
 175 {
 176   char const *s;
 177
 178 #if _LIBC || GNULIB_STRERROR_R_POSIX || defined HAVE_STRERROR_R
 179   char errbuf[1024];
 180 # if _LIBC || (!GNULIB_STRERROR_R_POSIX && STRERROR_R_CHAR_P)
 181   s = __strerror_r (errnum, errbuf, sizeof errbuf);
 182 # else
 183   if (__strerror_r (errnum, errbuf, sizeof errbuf) == 0)
 184     s = errbuf;
 185   else
 186     s = 0;
 187 # endif
 188 #else
 189   s = strerror (errnum);
 190 #endif
 191
 192 #if !_LIBC
 193   if (! s)
 194     s = _("Unknown system error");
 195 #endif
 196
 197 #if _LIBC
 198   __fxprintf (NULL, ": %s", s);
 199 #else
 200   fprintf (stderr, ": %s", s);
 201 #endif
 202 }
 203
 204 static void _GL_ATTRIBUTE_FORMAT_PRINTF_STANDARD (3, 0) _GL_ARG_NONNULL ((3))
 205 error_tail (int status, int errnum, const char *message, va_list args)
 206 {
 207 #if _LIBC
 208   if (_IO_fwide (stderr, 0) > 0)
 209     {
 210       size_t len = strlen (message) + 1;
 211       wchar_t *wmessage = NULL;
 212       mbstate_t st;
 213       size_t res;
 214       const char *tmp;
 215       bool use_malloc = false;
 216
 217       while (1)
 218         {
 219           if (__libc_use_alloca (len * sizeof (wchar_t)))
 220             wmessage = (wchar_t *) alloca (len * sizeof (wchar_t));
 221           else
 222             {
 223               if (!use_malloc)
 224                 wmessage = NULL;
 225
 226               wchar_t *p = (wchar_t *) realloc (wmessage,
 227                                                 len * sizeof (wchar_t));
 228               if (p == NULL)
 229                 {
 230                   free (wmessage);
 231                   fputws_unlocked (L"out of memory\n", stderr);
 232                   return;
 233                 }
 234               wmessage = p;
 235               use_malloc = true;
 236             }
 237
 238           memset (&st, '\0', sizeof (st));
 239           tmp = message;
 240
 241           res = mbsrtowcs (wmessage, &tmp, len, &st);
 242           if (res != len)
 243             break;
 244
 245           if (__builtin_expect (len >= SIZE_MAX / sizeof (wchar_t) / 2, 0))
 246             {
 247               /* This really should not happen if everything is fine.  */
 248               res = (size_t) -1;
 249               break;
 250             }
 251
 252           len *= 2;
 253         }
 254
 255       if (res == (size_t) -1)
 256         {
 257           /* The string cannot be converted.  */
 258           if (use_malloc)
 259             {
 260               free (wmessage);
 261               use_malloc = false;
 262             }
 263           wmessage = (wchar_t *) L"???";
 264         }
 265
 266       __vfwprintf (stderr, wmessage, args);
 267
 268       if (use_malloc)
 269         free (wmessage);
 270     }
 271   else
 272 #endif
 273     vfprintf (stderr, message, args);
 274
 275   ++error_message_count;
 276   if (errnum)
 277     print_errno_message (errnum);
 278 #if _LIBC
 279   __fxprintf (NULL, "\n");
 280 #else
 281   putc ('\n', stderr);
 282 #endif
 283   fflush (stderr);
 284   if (status)
 285     exit (status);
 286 }
 287
 288
 289 /* Print the program name and error message MESSAGE, which is a printf-style
 290    format string with optional args.
 291    If ERRNUM is nonzero, print its corresponding system error message.
 292    Exit with status STATUS if it is nonzero.  */
 293 void
 294 error (int status, int errnum, const char *message, ...)
 295 {
 296   va_list args;
 297
 298 #if defined _LIBC && defined __libc_ptf_call
 299   /* We do not want this call to be cut short by a thread
 300      cancellation.  Therefore disable cancellation for now.  */
 301   int state = PTHREAD_CANCEL_ENABLE;
 302   __libc_ptf_call (pthread_setcancelstate, (PTHREAD_CANCEL_DISABLE, &state),
 303                    0);
 304 #endif
 305
 306   flush_stdout ();
 307 #ifdef _LIBC
 308   _IO_flockfile (stderr);
 309 #endif
 310   if (error_print_progname)
 311     (*error_print_progname) ();
 312   else
 313     {
 314 #if _LIBC
 315       __fxprintf (NULL, "%s: ", program_name);
 316 #else
 317       fprintf (stderr, "%s: ", program_name);
 318 #endif
 319     }
 320
 321   va_start (args, message);
 322   error_tail (status, errnum, message, args);
 323   va_end (args);
 324
 325 #ifdef _LIBC
 326   _IO_funlockfile (stderr);
 327 # ifdef __libc_ptf_call
 328   __libc_ptf_call (pthread_setcancelstate, (state, NULL), 0);
 329 # endif
 330 #endif
 331 }
 332 \f
 333 /* Sometimes we want to have at most one error per line.  This
 334    variable controls whether this mode is selected or not.  */
 335 int error_one_per_line;
 336
 337 void
 338 error_at_line (int status, int errnum, const char *file_name,
 339                unsigned int line_number, const char *message, ...)
 340 {
 341   va_list args;
 342
 343   if (error_one_per_line)
 344     {
 345       static const char *old_file_name;
 346       static unsigned int old_line_number;
 347
 348       if (old_line_number == line_number
 349           && (file_name == old_file_name
 350               || (old_file_name != NULL
 351                   && file_name != NULL
 352                   && strcmp (old_file_name, file_name) == 0)))
 353
 354         /* Simply return and print nothing.  */
 355         return;
 356
 357       old_file_name = file_name;
 358       old_line_number = line_number;
 359     }
 360
 361 #if defined _LIBC && defined __libc_ptf_call
 362   /* We do not want this call to be cut short by a thread
 363      cancellation.  Therefore disable cancellation for now.  */
 364   int state = PTHREAD_CANCEL_ENABLE;
 365   __libc_ptf_call (pthread_setcancelstate, (PTHREAD_CANCEL_DISABLE, &state),
 366                    0);
 367 #endif
 368
 369   flush_stdout ();
 370 #ifdef _LIBC
 371   _IO_flockfile (stderr);
 372 #endif
 373   if (error_print_progname)
 374     (*error_print_progname) ();
 375   else
 376     {
 377 #if _LIBC
 378       __fxprintf (NULL, "%s:", program_name);
 379 #else
 380       fprintf (stderr, "%s:", program_name);
 381 #endif
 382     }
 383
 384 #if _LIBC
 385   __fxprintf (NULL, file_name != NULL ? "%s:%u: " : " ",
 386               file_name, line_number);
 387 #else
 388   fprintf (stderr, file_name != NULL ? "%s:%u: " : " ",
 389            file_name, line_number);
 390 #endif
 391
 392   va_start (args, message);
 393   error_tail (status, errnum, message, args);
 394   va_end (args);
 395
 396 #ifdef _LIBC
 397   _IO_funlockfile (stderr);
 398 # ifdef __libc_ptf_call
 399   __libc_ptf_call (pthread_setcancelstate, (state, NULL), 0);
 400 # endif
 401 #endif
 402 }
 403
 404 #ifdef _LIBC
 405 /* Make the weak alias.  */
 406 # undef error
 407 # undef error_at_line
 408 weak_alias (__error, error)
 409 weak_alias (__error_at_line, error_at_line)
 410 #endif