sysdeps/generic/sysd-stdio.c

   1 /* Copyright (C) 1991, 92, 93, 94, 95, 96, 97 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include <errno.h>
  20 #include <stddef.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <sys/types.h>
  25 #include <sys/stat.h>
  26 #include <fcntl.h>
  27 #include <unistd.h>
  28
  29 /* Read N bytes into BUF from COOKIE.  */
  30 int
  31 __stdio_read (void *cookie, char *buf, size_t n;)
  32 {
  33   const int fd = (int) cookie;
  34 #if     defined (EINTR) && defined (EINTR_REPEAT)
  35   int save = errno;
  36   int nread;
  37
  38  try:;
  39   __set_errno (0);
  40   nread = __read (fd, buf, (int) n);
  41   if (nread < 0)
  42     {
  43       if (errno == EINTR)
  44         goto try;
  45       return -1;
  46     }
  47   __set_errno (save);
  48   return nread;
  49
  50 #else   /* No EINTR.  */
  51   return __read (fd, buf, n);
  52 #endif
  53 }
  54
  55
  56 /* Write N bytes from BUF to COOKIE.  */
  57 int
  58 __stdio_write (void *cookie, const char *buf, size_t n)
  59 {
  60   const int fd = (int) cookie;
  61   register size_t written = 0;
  62
  63   while (n > 0)
  64     {
  65       int count = __write (fd, buf, (int) n);
  66       if (count > 0)
  67         {
  68           buf += count;
  69           written += count;
  70           n -= count;
  71         }
  72       else if (count < 0
  73 #if     defined (EINTR) && defined (EINTR_REPEAT)
  74                && errno != EINTR
  75 #endif
  76                )
  77         /* Write error.  */
  78         return -1;
  79     }
  80
  81   return (int) written;
  82 }
  83
  84
  85 /* Move COOKIE's file position *POS bytes, according to WHENCE.
  86    The new file position is stored in *POS.
  87    Returns zero if successful, nonzero if not.  */
  88 int
  89 __stdio_seek (void *cookie, fpos_t *pos, int whence)
  90 {
  91   off_t new;
  92   new = __lseek ((int) cookie, (off_t) *pos, whence);
  93   if (new < 0)
  94     return 1;
  95   *pos = (fpos_t) new;
  96   return 0;
  97 }
  98
  99
 100 /* Close COOKIE.  */
 101 int
 102 __stdio_close (void *cookie)
 103 {
 104   return __close ((int) cookie);
 105 }
 106
 107 /* Return the POSIX.1 file descriptor associated with COOKIE,
 108    or -1 for errors.  If COOKIE does not relate to any POSIX.1 file
 109    descriptor, this should return -1 with errno set to EOPNOTSUPP.  */
 110 int
 111 __stdio_fileno (void *cookie)
 112 {
 113   return (int) cookie;
 114 }
 115
 116
 117 /* Open the given file with the mode given in the __io_mode argument.  */
 118 int
 119 __stdio_open (const char *filename, __io_mode m, void **cookieptr)
 120 {
 121   int fd;
 122   int mode;
 123
 124   if (m.__read && m.__write)
 125     mode = O_RDWR;
 126   else
 127     mode = m.__read ? O_RDONLY : O_WRONLY;
 128
 129   if (m.__append)
 130     mode |= O_APPEND;
 131   if (m.__exclusive)
 132     mode |= O_EXCL;
 133   if (m.__truncate)
 134     mode |= O_TRUNC;
 135
 136   if (m.__create)
 137     fd = __open (filename, mode | O_CREAT,
 138                  S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH);
 139   else
 140     fd = __open (filename, mode);
 141
 142   if (fd < 0)
 143     return -1;
 144
 145   *cookieptr = (void *) fd;
 146   return 0;
 147 }
 148
 149
 150 /* Open FILENAME with the mode in M.  Use the same magic cookie
 151    already in *COOKIEPTR if possible, closing the old cookie with CLOSEFN.  */
 152 int
 153 __stdio_reopen (const char *filename, __io_mode m, void **cookieptr,
 154                 __io_close_fn closefn)
 155 {
 156   void *newcookie;
 157
 158   /* We leave the old descriptor open while we open the file.
 159      That way ``freopen ("/dev/stdin", "r", stdin)'' works.  */
 160
 161   if (__stdio_open (filename, m, &newcookie))
 162     {
 163       if (errno == ENFILE || errno == EMFILE)
 164         {
 165           /* We are out of file descriptors.  Try closing the old one and
 166              retrying the open.  */
 167           (void) (*closefn) (*cookieptr);
 168           if (__stdio_open (filename, m, &newcookie))
 169             return -1;
 170         }
 171       else
 172         return -1;
 173     }
 174
 175   if (newcookie != *cookieptr)
 176     {
 177       if (closefn != __stdio_close ||
 178           /* Try to move the descriptor to the desired one.  */
 179           __dup2 ((int) newcookie, (int) *cookieptr) < 0)
 180         /* Didn't work.  Give the caller the new cookie.  */
 181         *cookieptr = newcookie;
 182     }
 183
 184   return 0;
 185 }