gl/stdio-write.c

   1 /* POSIX compatible FILE stream write function.
   2    Copyright (C) 2008-2024 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2008.
   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 #include <config.h>
  19
  20 /* Specification.  */
  21 #include <stdio.h>
  22
  23 /* Replace these functions only if module 'nonblocking' or module 'sigpipe' is
  24    requested.  */
  25 #if GNULIB_NONBLOCKING || GNULIB_SIGPIPE
  26
  27 /* On native Windows platforms, SIGPIPE does not exist.  When write() is
  28    called on a pipe with no readers, WriteFile() fails with error
  29    GetLastError() = ERROR_NO_DATA, and write() in consequence fails with
  30    error EINVAL.  This write() function is at the basis of the function
  31    which flushes the buffer of a FILE stream.  */
  32
  33 # if defined _WIN32 && ! defined __CYGWIN__
  34
  35 #  include <errno.h>
  36 #  include <signal.h>
  37 #  include <io.h>
  38
  39 #  define WIN32_LEAN_AND_MEAN  /* avoid including junk */
  40 #  include <windows.h>
  41
  42 #  if GNULIB_MSVC_NOTHROW
  43 #   include "msvc-nothrow.h"
  44 #  else
  45 #   include <io.h>
  46 #  endif
  47
  48 /* Don't assume that UNICODE is not defined.  */
  49 #  undef GetNamedPipeHandleState
  50 #  define GetNamedPipeHandleState GetNamedPipeHandleStateA
  51
  52 #  if GNULIB_NONBLOCKING
  53 #   define CLEAR_ERRNO \
  54       errno = 0;
  55 #   define HANDLE_ENOSPC \
  56           if (errno == ENOSPC && ferror (stream))                             \
  57             {                                                                 \
  58               int fd = fileno (stream);                                       \
  59               if (fd >= 0)                                                    \
  60                 {                                                             \
  61                   HANDLE h = (HANDLE) _get_osfhandle (fd);                    \
  62                   if (GetFileType (h) == FILE_TYPE_PIPE)                      \
  63                     {                                                         \
  64                       /* h is a pipe or socket.  */                           \
  65                       DWORD state;                                            \
  66                       if (GetNamedPipeHandleState (h, &state, NULL, NULL,     \
  67                                                    NULL, NULL, 0)             \
  68                           && (state & PIPE_NOWAIT) != 0)                      \
  69                         /* h is a pipe in non-blocking mode.                  \
  70                            Change errno from ENOSPC to EAGAIN.  */            \
  71                         errno = EAGAIN;                                       \
  72                     }                                                         \
  73                 }                                                             \
  74             }                                                                 \
  75           else
  76 #  else
  77 #   define CLEAR_ERRNO
  78 #   define HANDLE_ENOSPC
  79 #  endif
  80
  81 #  if GNULIB_SIGPIPE
  82 #   define CLEAR_LastError \
  83       SetLastError (0);
  84 #   define HANDLE_ERROR_NO_DATA \
  85           if (GetLastError () == ERROR_NO_DATA && ferror (stream))            \
  86             {                                                                 \
  87               int fd = fileno (stream);                                       \
  88               if (fd >= 0                                                     \
  89                   && GetFileType ((HANDLE) _get_osfhandle (fd))               \
  90                      == FILE_TYPE_PIPE)                                       \
  91                 {                                                             \
  92                   /* Try to raise signal SIGPIPE.  */                         \
  93                   raise (SIGPIPE);                                            \
  94                   /* If it is currently blocked or ignored, change errno from \
  95                      EINVAL to EPIPE.  */                                     \
  96                   errno = EPIPE;                                              \
  97                 }                                                             \
  98             }                                                                 \
  99           else
 100 #  else
 101 #   define CLEAR_LastError
 102 #   define HANDLE_ERROR_NO_DATA
 103 #  endif
 104
 105 #  define CALL_WITH_SIGPIPE_EMULATION(RETTYPE, EXPRESSION, FAILED) \
 106   if (ferror (stream))                                                        \
 107     return (EXPRESSION);                                                      \
 108   else                                                                        \
 109     {                                                                         \
 110       RETTYPE ret;                                                            \
 111       CLEAR_ERRNO                                                             \
 112       CLEAR_LastError                                                         \
 113       ret = (EXPRESSION);                                                     \
 114       if (FAILED)                                                             \
 115         {                                                                     \
 116           HANDLE_ENOSPC                                                       \
 117           HANDLE_ERROR_NO_DATA                                                \
 118           ;                                                                   \
 119         }                                                                     \
 120       return ret;                                                             \
 121     }
 122
 123 #  if !REPLACE_PRINTF_POSIX /* avoid collision with printf.c */
 124 int
 125 printf (const char *format, ...)
 126 {
 127   int retval;
 128   va_list args;
 129
 130   va_start (args, format);
 131   retval = vfprintf (stdout, format, args);
 132   va_end (args);
 133
 134   return retval;
 135 }
 136 #  endif
 137
 138 #  if !REPLACE_FPRINTF_POSIX /* avoid collision with fprintf.c */
 139 int
 140 fprintf (FILE *stream, const char *format, ...)
 141 {
 142   int retval;
 143   va_list args;
 144
 145   va_start (args, format);
 146   retval = vfprintf (stream, format, args);
 147   va_end (args);
 148
 149   return retval;
 150 }
 151 #  endif
 152
 153 #  if !REPLACE_VPRINTF_POSIX /* avoid collision with vprintf.c */
 154 int
 155 vprintf (const char *format, va_list args)
 156 {
 157   return vfprintf (stdout, format, args);
 158 }
 159 #  endif
 160
 161 #  if !REPLACE_VFPRINTF_POSIX /* avoid collision with vfprintf.c */
 162 int
 163 vfprintf (FILE *stream, const char *format, va_list args)
 164 #undef vfprintf
 165 {
 166   CALL_WITH_SIGPIPE_EMULATION (int, vfprintf (stream, format, args), ret == EOF)
 167 }
 168 #  endif
 169
 170 int
 171 putchar (int c)
 172 {
 173   return fputc (c, stdout);
 174 }
 175
 176 int
 177 fputc (int c, FILE *stream)
 178 #undef fputc
 179 {
 180   CALL_WITH_SIGPIPE_EMULATION (int, fputc (c, stream), ret == EOF)
 181 }
 182
 183 int
 184 fputs (const char *string, FILE *stream)
 185 #undef fputs
 186 {
 187   CALL_WITH_SIGPIPE_EMULATION (int, fputs (string, stream), ret == EOF)
 188 }
 189
 190 int
 191 puts (const char *string)
 192 #undef puts
 193 {
 194   FILE *stream = stdout;
 195   CALL_WITH_SIGPIPE_EMULATION (int, puts (string), ret == EOF)
 196 }
 197
 198 size_t
 199 fwrite (const void *ptr, size_t s, size_t n, FILE *stream)
 200 #undef fwrite
 201 {
 202   CALL_WITH_SIGPIPE_EMULATION (size_t, fwrite (ptr, s, n, stream), ret < n)
 203 }
 204
 205 # endif
 206 #endif