sysdeps/posix/fpathconf.c

   1 /* Copyright (C) 1991-2017 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 Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the 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    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <stddef.h>
  20 #include <unistd.h>
  21 #include <limits.h>
  22 #include <sys/stat.h>
  23 #include <sys/statfs.h>
  24 #include <sys/statvfs.h>
  25
  26
  27 /* Get file-specific information about descriptor FD.  */
  28 long int
  29 __fpathconf (int fd, int name)
  30 {
  31   if (fd < 0)
  32     {
  33       __set_errno (EBADF);
  34       return -1;
  35     }
  36
  37   switch (name)
  38     {
  39     default:
  40       __set_errno (EINVAL);
  41       return -1;
  42
  43     case _PC_LINK_MAX:
  44 #ifdef  LINK_MAX
  45       return LINK_MAX;
  46 #else
  47       return -1;
  48 #endif
  49
  50     case _PC_MAX_CANON:
  51 #ifdef  MAX_CANON
  52       return MAX_CANON;
  53 #else
  54       return -1;
  55 #endif
  56
  57     case _PC_MAX_INPUT:
  58 #ifdef  MAX_INPUT
  59       return MAX_INPUT;
  60 #else
  61       return -1;
  62 #endif
  63
  64     case _PC_NAME_MAX:
  65 #ifdef  NAME_MAX
  66       {
  67         struct statvfs64 sv;
  68         int save_errno = errno;
  69
  70         if (__fstatvfs64 (fd, &sv) < 0)
  71           {
  72             if (errno == ENOSYS)
  73               {
  74                 __set_errno (save_errno);
  75                 return NAME_MAX;
  76               }
  77             else if (errno == ENODEV)
  78               __set_errno (EINVAL);
  79
  80             return -1;
  81           }
  82         else
  83           {
  84             return sv.f_namemax;
  85           }
  86       }
  87 #else
  88       return -1;
  89 #endif
  90
  91     case _PC_PATH_MAX:
  92 #ifdef  PATH_MAX
  93       return PATH_MAX;
  94 #else
  95       return -1;
  96 #endif
  97
  98     case _PC_PIPE_BUF:
  99 #ifdef  PIPE_BUF
 100       return PIPE_BUF;
 101 #else
 102       return -1;
 103 #endif
 104
 105     case _PC_CHOWN_RESTRICTED:
 106 #ifdef  _POSIX_CHOWN_RESTRICTED
 107       return _POSIX_CHOWN_RESTRICTED;
 108 #else
 109       return -1;
 110 #endif
 111
 112     case _PC_NO_TRUNC:
 113 #ifdef  _POSIX_NO_TRUNC
 114       return _POSIX_NO_TRUNC;
 115 #else
 116       return -1;
 117 #endif
 118
 119     case _PC_VDISABLE:
 120 #ifdef  _POSIX_VDISABLE
 121       return _POSIX_VDISABLE;
 122 #else
 123       return -1;
 124 #endif
 125
 126     case _PC_SYNC_IO:
 127 #ifdef  _POSIX_SYNC_IO
 128       return _POSIX_SYNC_IO;
 129 #else
 130       return -1;
 131 #endif
 132
 133     case _PC_ASYNC_IO:
 134 #ifdef  _POSIX_ASYNC_IO
 135       {
 136         /* AIO is only allowed on regular files and block devices.  */
 137         struct stat64 st;
 138
 139         if (__fxstat64 (_STAT_VER, fd, &st) < 0
 140             || (! S_ISREG (st.st_mode) && ! S_ISBLK (st.st_mode)))
 141           return -1;
 142         else
 143           return 1;
 144       }
 145 #else
 146       return -1;
 147 #endif
 148
 149     case _PC_PRIO_IO:
 150 #ifdef  _POSIX_PRIO_IO
 151       return _POSIX_PRIO_IO;
 152 #else
 153       return -1;
 154 #endif
 155
 156     case _PC_SOCK_MAXBUF:
 157 #ifdef  SOCK_MAXBUF
 158       return SOCK_MAXBUF;
 159 #else
 160       return -1;
 161 #endif
 162
 163     case _PC_FILESIZEBITS:
 164 #ifdef FILESIZEBITS
 165       return FILESIZEBITS;
 166 #else
 167       /* We let platforms with larger file sizes overwrite this value.  */
 168       return 32;
 169 #endif
 170
 171     case _PC_REC_INCR_XFER_SIZE:
 172       /* XXX It is not entirely clear what the limit is supposed to do.
 173          What is incremented?  */
 174       return -1;
 175
 176     case _PC_REC_MAX_XFER_SIZE:
 177       /* XXX It is not entirely clear what the limit is supposed to do.
 178          In general there is no top limit of the number of bytes which
 179          case be transported at once.  */
 180       return -1;
 181
 182     case _PC_REC_MIN_XFER_SIZE:
 183       {
 184         /* XXX It is not entirely clear what the limit is supposed to do.
 185            I assume this is the block size of the filesystem.  */
 186         struct statvfs64 sv;
 187
 188         if (__fstatvfs64 (fd, &sv) < 0)
 189           return -1;
 190         return sv.f_bsize;
 191       }
 192
 193     case _PC_REC_XFER_ALIGN:
 194       {
 195         /* XXX It is not entirely clear what the limit is supposed to do.
 196            I assume that the number should reflect the minimal block
 197            alignment.  */
 198         struct statvfs64 sv;
 199
 200         if (__fstatvfs64 (fd, &sv) < 0)
 201           return -1;
 202         return sv.f_frsize;
 203       }
 204
 205     case _PC_ALLOC_SIZE_MIN:
 206       {
 207         /* XXX It is not entirely clear what the limit is supposed to do.
 208            I assume that the number should reflect the minimal block
 209            alignment.  */
 210         struct statvfs64 sv;
 211
 212         if (__fstatvfs64 (fd, &sv) < 0)
 213           return -1;
 214         return sv.f_frsize;
 215       }
 216
 217     case _PC_SYMLINK_MAX:
 218       /* In general there are no limits.  If a system has one it should
 219          overwrite this case.  */
 220       return -1;
 221
 222     case _PC_2_SYMLINKS:
 223       /* Unix systems generally have symlinks.  */
 224       return 1;
 225     }
 226 }
 227
 228 #undef __fpathconf
 229 weak_alias (__fpathconf, fpathconf)