sysdeps/posix/fpathconf.c

   1 /* Copyright (C) 1991-2014 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 (fd, name)
  30      int fd;
  31      int name;
  32 {
  33   if (fd < 0)
  34     {
  35       __set_errno (EBADF);
  36       return -1;
  37     }
  38
  39   switch (name)
  40     {
  41     default:
  42       __set_errno (EINVAL);
  43       return -1;
  44
  45     case _PC_LINK_MAX:
  46 #ifdef  LINK_MAX
  47       return LINK_MAX;
  48 #else
  49       return -1;
  50 #endif
  51
  52     case _PC_MAX_CANON:
  53 #ifdef  MAX_CANON
  54       return MAX_CANON;
  55 #else
  56       return -1;
  57 #endif
  58
  59     case _PC_MAX_INPUT:
  60 #ifdef  MAX_INPUT
  61       return MAX_INPUT;
  62 #else
  63       return -1;
  64 #endif
  65
  66     case _PC_NAME_MAX:
  67 #ifdef  NAME_MAX
  68       {
  69         struct statfs buf;
  70         int save_errno = errno;
  71
  72         if (__fstatfs (fd, &buf) < 0)
  73           {
  74             if (errno == ENOSYS)
  75               {
  76                 __set_errno (save_errno);
  77                 return NAME_MAX;
  78               }
  79             else if (errno == ENODEV)
  80               __set_errno (EINVAL);
  81
  82             return -1;
  83           }
  84         else
  85           {
  86 #ifdef _STATFS_F_NAMELEN
  87             return buf.f_namelen;
  88 #else
  89 # ifdef _STATFS_F_NAME_MAX
  90             return buf.f_name_max;
  91 # else
  92             return NAME_MAX;
  93 # endif
  94 #endif
  95           }
  96       }
  97 #else
  98       return -1;
  99 #endif
 100
 101     case _PC_PATH_MAX:
 102 #ifdef  PATH_MAX
 103       return PATH_MAX;
 104 #else
 105       return -1;
 106 #endif
 107
 108     case _PC_PIPE_BUF:
 109 #ifdef  PIPE_BUF
 110       return PIPE_BUF;
 111 #else
 112       return -1;
 113 #endif
 114
 115     case _PC_CHOWN_RESTRICTED:
 116 #ifdef  _POSIX_CHOWN_RESTRICTED
 117       return _POSIX_CHOWN_RESTRICTED;
 118 #else
 119       return -1;
 120 #endif
 121
 122     case _PC_NO_TRUNC:
 123 #ifdef  _POSIX_NO_TRUNC
 124       return _POSIX_NO_TRUNC;
 125 #else
 126       return -1;
 127 #endif
 128
 129     case _PC_VDISABLE:
 130 #ifdef  _POSIX_VDISABLE
 131       return _POSIX_VDISABLE;
 132 #else
 133       return -1;
 134 #endif
 135
 136     case _PC_SYNC_IO:
 137 #ifdef  _POSIX_SYNC_IO
 138       return _POSIX_SYNC_IO;
 139 #else
 140       return -1;
 141 #endif
 142
 143     case _PC_ASYNC_IO:
 144 #ifdef  _POSIX_ASYNC_IO
 145       {
 146         /* AIO is only allowed on regular files and block devices.  */
 147         struct stat64 st;
 148
 149         if (__fxstat64 (_STAT_VER, fd, &st) < 0
 150             || (! S_ISREG (st.st_mode) && ! S_ISBLK (st.st_mode)))
 151           return -1;
 152         else
 153           return 1;
 154       }
 155 #else
 156       return -1;
 157 #endif
 158
 159     case _PC_PRIO_IO:
 160 #ifdef  _POSIX_PRIO_IO
 161       return _POSIX_PRIO_IO;
 162 #else
 163       return -1;
 164 #endif
 165
 166     case _PC_SOCK_MAXBUF:
 167 #ifdef  SOCK_MAXBUF
 168       return SOCK_MAXBUF;
 169 #else
 170       return -1;
 171 #endif
 172
 173     case _PC_FILESIZEBITS:
 174 #ifdef FILESIZEBITS
 175       return FILESIZEBITS;
 176 #else
 177       /* We let platforms with larger file sizes overwrite this value.  */
 178       return 32;
 179 #endif
 180
 181     case _PC_REC_INCR_XFER_SIZE:
 182       /* XXX It is not entirely clear what the limit is supposed to do.
 183          What is incremented?  */
 184       return -1;
 185
 186     case _PC_REC_MAX_XFER_SIZE:
 187       /* XXX It is not entirely clear what the limit is supposed to do.
 188          In general there is no top limit of the number of bytes which
 189          case be transported at once.  */
 190       return -1;
 191
 192     case _PC_REC_MIN_XFER_SIZE:
 193       {
 194         /* XXX It is not entirely clear what the limit is supposed to do.
 195            I assume this is the block size of the filesystem.  */
 196         struct statvfs64 sv;
 197
 198         if (__fstatvfs64 (fd, &sv) < 0)
 199           return -1;
 200         return sv.f_bsize;
 201       }
 202
 203     case _PC_REC_XFER_ALIGN:
 204       {
 205         /* XXX It is not entirely clear what the limit is supposed to do.
 206            I assume that the number should reflect the minimal block
 207            alignment.  */
 208         struct statvfs64 sv;
 209
 210         if (__fstatvfs64 (fd, &sv) < 0)
 211           return -1;
 212         return sv.f_frsize;
 213       }
 214
 215     case _PC_ALLOC_SIZE_MIN:
 216       {
 217         /* XXX It is not entirely clear what the limit is supposed to do.
 218            I assume that the number should reflect the minimal block
 219            alignment.  */
 220         struct statvfs64 sv;
 221
 222         if (__fstatvfs64 (fd, &sv) < 0)
 223           return -1;
 224         return sv.f_frsize;
 225       }
 226
 227     case _PC_SYMLINK_MAX:
 228       /* In general there are no limits.  If a system has one it should
 229          overwrite this case.  */
 230       return -1;
 231
 232     case _PC_2_SYMLINKS:
 233       /* Unix systems generally have symlinks.  */
 234       return 1;
 235     }
 236 }
 237
 238 #undef __fpathconf
 239 weak_alias (__fpathconf, fpathconf)