lib/stdio-write.c

   1 /* POSIX compatible FILE stream write function.
   2    Copyright (C) 2008-2019 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2008.
   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 #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 #  if GNULIB_NONBLOCKING
  49 #   define CLEAR_ERRNO \
  50       errno = 0;
  51 #   define HANDLE_ENOSPC \
  52           if (errno == ENOSPC && ferror (stream))                             \
  53             {                                                                 \
  54               int fd = fileno (stream);                                       \
  55               if (fd >= 0)                                                    \
  56                 {                                                             \
  57                   HANDLE h = (HANDLE) _get_osfhandle (fd);                    \
  58                   if (GetFileType (h) == FILE_TYPE_PIPE)                      \
  59                     {                                                         \
  60                       /* h is a pipe or socket.  */                           \
  61                       DWORD state;                                            \
  62                       if (GetNamedPipeHandleState (h, &state, NULL, NULL,     \
  63                                                    NULL, NULL, 0)             \
  64                           && (state & PIPE_NOWAIT) != 0)                      \
  65                         /* h is a pipe in non-blocking mode.                  \
  66                            Change errno from ENOSPC to EAGAIN.  */            \
  67                         errno = EAGAIN;                                       \
  68                     }                                                         \
  69                 }                                                             \
  70             }                                                                 \
  71           else
  72 #  else
  73 #   define CLEAR_ERRNO
  74 #   define HANDLE_ENOSPC
  75 #  endif
  76
  77 #  if GNULIB_SIGPIPE
  78 #   define CLEAR_LastError \
  79       SetLastError (0);
  80 #   define HANDLE_ERROR_NO_DATA \
  81           if (GetLastError () == ERROR_NO_DATA && ferror (stream))            \
  82             {                                                                 \
  83               int fd = fileno (stream);                                       \
  84               if (fd >= 0                                                     \
  85                   && GetFileType ((HANDLE) _get_osfhandle (fd))               \
  86                      == FILE_TYPE_PIPE)                                       \
  87                 {                                                             \
  88                   /* Try to raise signal SIGPIPE.  */                         \
  89                   raise (SIGPIPE);                                            \
  90                   /* If it is currently blocked or ignored, change errno from \
  91                      EINVAL to EPIPE.  */                                     \
  92                   errno = EPIPE;                                              \
  93                 }                                                             \
  94             }                                                                 \
  95           else
  96 #  else
  97 #   define CLEAR_LastError
  98 #   define HANDLE_ERROR_NO_DATA
  99 #  endif
 100
 101 #  define CALL_WITH_SIGPIPE_EMULATION(RETTYPE, EXPRESSION, FAILED) \
 102   if (ferror (stream))                                                        \
 103     return (EXPRESSION);                                                      \
 104   else                                                                        \
 105     {                                                                         \
 106       RETTYPE ret;                                                            \
 107       CLEAR_ERRNO                                                             \
 108       CLEAR_LastError                                                         \
 109       ret = (EXPRESSION);                                                     \
 110       if (FAILED)                                                             \
 111         {                                                                     \
 112           HANDLE_ENOSPC                                                       \
 113           HANDLE_ERROR_NO_DATA                                                \
 114           ;                                                                   \
 115         }                                                                     \
 116       return ret;                                                             \
 117     }
 118
 119 #  if !REPLACE_PRINTF_POSIX /* avoid collision with printf.c */
 120 int
 121 printf (const char *format, ...)
 122 {
 123   int retval;
 124   va_list args;
 125
 126   va_start (args, format);
 127   retval = vfprintf (stdout, format, args);
 128   va_end (args);
 129
 130   return retval;
 131 }
 132 #  endif
 133
 134 #  if !REPLACE_FPRINTF_POSIX /* avoid collision with fprintf.c */
 135 int
 136 fprintf (FILE *stream, const char *format, ...)
 137 {
 138   int retval;
 139   va_list args;
 140
 141   va_start (args, format);
 142   retval = vfprintf (stream, format, args);
 143   va_end (args);
 144
 145   return retval;
 146 }
 147 #  endif
 148
 149 #  if !REPLACE_VPRINTF_POSIX /* avoid collision with vprintf.c */
 150 int
 151 vprintf (const char *format, va_list args)
 152 {
 153   return vfprintf (stdout, format, args);
 154 }
 155 #  endif
 156
 157 #  if !REPLACE_VFPRINTF_POSIX /* avoid collision with vfprintf.c */
 158 int
 159 vfprintf (FILE *stream, const char *format, va_list args)
 160 #undef vfprintf
 161 {
 162   CALL_WITH_SIGPIPE_EMULATION (int, vfprintf (stream, format, args), ret == EOF)
 163 }
 164 #  endif
 165
 166 int
 167 putchar (int c)
 168 {
 169   return fputc (c, stdout);
 170 }
 171
 172 int
 173 fputc (int c, FILE *stream)
 174 #undef fputc
 175 {
 176   CALL_WITH_SIGPIPE_EMULATION (int, fputc (c, stream), ret == EOF)
 177 }
 178
 179 int
 180 fputs (const char *string, FILE *stream)
 181 #undef fputs
 182 {
 183   CALL_WITH_SIGPIPE_EMULATION (int, fputs (string, stream), ret == EOF)
 184 }
 185
 186 int
 187 puts (const char *string)
 188 #undef puts
 189 {
 190   FILE *stream = stdout;
 191   CALL_WITH_SIGPIPE_EMULATION (int, puts (string), ret == EOF)
 192 }
 193
 194 size_t
 195 fwrite (const void *ptr, size_t s, size_t n, FILE *stream)
 196 #undef fwrite
 197 {
 198   CALL_WITH_SIGPIPE_EMULATION (size_t, fwrite (ptr, s, n, stream), ret < n)
 199 }
 200
 201 # endif
 202 #endif