lib/error.c

   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.  */
  60 void (*error_print_progname) (void);
  61
  62 /* This variable is incremented each time 'error' is called.  */
  63 unsigned 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.  */
  75 extern void __error (int status, int errnum, const char *message, ...)
  76      __attribute__ ((__format__ (__printf__, 3, 4)));
  77 extern 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
 116 char *strerror_r (int errnum, char *buf, size_t buflen);
 117 #  else
 118 int 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.  */
 131 static int
 132 is_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
 149 static void
 150 flush_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
 174 static void
 175 print_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
 205 static void _GL_ATTRIBUTE_FORMAT_PRINTF (3, 0) _GL_ARG_NONNULL ((3))
 206 error_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.  */
 294 void
 295 error (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 \f
 334 /* Sometimes we want to have at most one error per line.  This
 335    variable controls whether this mode is selected or not.  */
 336 int error_one_per_line;
 337
 338 void
 339 error_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
 409 weak_alias (__error, error)
 410 weak_alias (__error_at_line, error_at_line)
 411 #endif