misc/error.c

   1 /* Error handler for noninteractive utilities
   2    Copyright (C) 1990-2022 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 \f
 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