sysdeps/posix/fpathconf.c

   1 /* Copyright (C) 1991,1995,1996,1998,2000,2001,2003
   2    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    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <stddef.h>
  21 #include <unistd.h>
  22 #include <limits.h>
  23 #include <sys/stat.h>
  24 #include <sys/statfs.h>
  25 #include <sys/statvfs.h>
  26
  27
  28 /* Get file-specific information about descriptor FD.  */
  29 long int
  30 __fpathconf (fd, name)
  31      int fd;
  32      int name;
  33 {
  34   if (fd < 0)
  35     {
  36       __set_errno (EBADF);
  37       return -1;
  38     }
  39
  40   switch (name)
  41     {
  42     default:
  43       __set_errno (EINVAL);
  44       return -1;
  45
  46     case _PC_LINK_MAX:
  47 #ifdef  LINK_MAX
  48       return LINK_MAX;
  49 #else
  50       return -1;
  51 #endif
  52
  53     case _PC_MAX_CANON:
  54 #ifdef  MAX_CANON
  55       return MAX_CANON;
  56 #else
  57       return -1;
  58 #endif
  59
  60     case _PC_MAX_INPUT:
  61 #ifdef  MAX_INPUT
  62       return MAX_INPUT;
  63 #else
  64       return -1;
  65 #endif
  66
  67     case _PC_NAME_MAX:
  68 #ifdef  NAME_MAX
  69       {
  70         struct statfs buf;
  71         int save_errno = errno;
  72
  73         if (__fstatfs (fd, &buf) < 0)
  74           {
  75             if (errno == ENOSYS)
  76               {
  77                 __set_errno (save_errno);
  78                 return NAME_MAX;
  79               }
  80             else if (errno == ENODEV)
  81               __set_errno (EINVAL);
  82
  83             return -1;
  84           }
  85         else
  86           {
  87 #ifdef _STATFS_F_NAMELEN
  88             return buf.f_namelen;
  89 #else
  90 # ifdef _STATFS_F_NAME_MAX
  91             return buf.f_name_max;
  92 # else
  93             return NAME_MAX;
  94 # endif
  95 #endif
  96           }
  97       }
  98 #else
  99       return -1;
 100 #endif
 101
 102     case _PC_PATH_MAX:
 103 #ifdef  PATH_MAX
 104       return PATH_MAX;
 105 #else
 106       return -1;
 107 #endif
 108
 109     case _PC_PIPE_BUF:
 110 #ifdef  PIPE_BUF
 111       return PIPE_BUF;
 112 #else
 113       return -1;
 114 #endif
 115
 116     case _PC_CHOWN_RESTRICTED:
 117 #ifdef  _POSIX_CHOWN_RESTRICTED
 118       return _POSIX_CHOWN_RESTRICTED;
 119 #else
 120       return -1;
 121 #endif
 122
 123     case _PC_NO_TRUNC:
 124 #ifdef  _POSIX_NO_TRUNC
 125       return _POSIX_NO_TRUNC;
 126 #else
 127       return -1;
 128 #endif
 129
 130     case _PC_VDISABLE:
 131 #ifdef  _POSIX_VDISABLE
 132       return _POSIX_VDISABLE;
 133 #else
 134       return -1;
 135 #endif
 136
 137     case _PC_SYNC_IO:
 138 #ifdef  _POSIX_SYNC_IO
 139       return _POSIX_SYNC_IO;
 140 #else
 141       return -1;
 142 #endif
 143
 144     case _PC_ASYNC_IO:
 145 #ifdef  _POSIX_ASYNC_IO
 146       {
 147         /* AIO is only allowed on regular files and block devices.  */
 148         struct stat64 st;
 149
 150         if (__fxstat64 (_STAT_VER, fd, &st) < 0
 151             || (! S_ISREG (st.st_mode) && ! S_ISBLK (st.st_mode)))
 152           return -1;
 153         else
 154           return 1;
 155       }
 156 #else
 157       return -1;
 158 #endif
 159
 160     case _PC_PRIO_IO:
 161 #ifdef  _POSIX_PRIO_IO
 162       return _POSIX_PRIO_IO;
 163 #else
 164       return -1;
 165 #endif
 166
 167     case _PC_SOCK_MAXBUF:
 168 #ifdef  SOCK_MAXBUF
 169       return SOCK_MAXBUF;
 170 #else
 171       return -1;
 172 #endif
 173
 174     case _PC_FILESIZEBITS:
 175 #ifdef FILESIZEBITS
 176       return FILESIZEBITS;
 177 #else
 178       /* We let platforms with larger file sizes overwrite this value.  */
 179       return 32;
 180 #endif
 181
 182     case _PC_REC_INCR_XFER_SIZE:
 183       /* XXX It is not entirely clear what the limit is supposed to do.
 184          What is incremented?  */
 185       return -1;
 186
 187     case _PC_REC_MAX_XFER_SIZE:
 188       /* XXX It is not entirely clear what the limit is supposed to do.
 189          In general there is no top limit of the number of bytes which
 190          case be transported at once.  */
 191       return -1;
 192
 193     case _PC_REC_MIN_XFER_SIZE:
 194       {
 195         /* XXX It is not entirely clear what the limit is supposed to do.
 196            I assume this is the block size of the filesystem.  */
 197         struct statvfs64 sv;
 198
 199         if (__fstatvfs64 (fd, &sv) < 0)
 200           return -1;
 201         return sv.f_bsize;
 202       }
 203
 204     case _PC_REC_XFER_ALIGN:
 205       {
 206         /* XXX It is not entirely clear what the limit is supposed to do.
 207            I assume that the number should reflect the minimal block
 208            alignment.  */
 209         struct statvfs64 sv;
 210
 211         if (__fstatvfs64 (fd, &sv) < 0)
 212           return -1;
 213         return sv.f_frsize;
 214       }
 215
 216     case _PC_ALLOC_SIZE_MIN:
 217       {
 218         /* XXX It is not entirely clear what the limit is supposed to do.
 219            I assume that the number should reflect the minimal block
 220            alignment.  */
 221         struct statvfs64 sv;
 222
 223         if (__fstatvfs64 (fd, &sv) < 0)
 224           return -1;
 225         return sv.f_frsize;
 226       }
 227
 228     case _PC_SYMLINK_MAX:
 229       /* In general there are no limits.  If a system has one it should
 230          overwrite this case.  */
 231       return -1;
 232
 233     case _PC_2_SYMLINKS:
 234       /* Unix systems generally have symlinks.  */
 235       return 1;
 236     }
 237 }
 238
 239 #undef __fpathconf
 240 weak_alias (__fpathconf, fpathconf)