sysdeps/posix/pathconf.c

   1 /* Copyright (C) 1991-2013 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 <fcntl.h>
  23 #include <sys/stat.h>
  24 #include <sys/statfs.h>
  25 #include <sys/statvfs.h>
  26
  27
  28 /* Get file-specific information about PATH.  */
  29 long int
  30 __pathconf (const char *path, int name)
  31 {
  32   if (path[0] == '\0')
  33     {
  34       __set_errno (ENOENT);
  35       return -1;
  36     }
  37
  38   switch (name)
  39     {
  40     default:
  41       __set_errno (EINVAL);
  42       return -1;
  43
  44     case _PC_LINK_MAX:
  45 #ifdef  LINK_MAX
  46       return LINK_MAX;
  47 #else
  48       return -1;
  49 #endif
  50
  51     case _PC_MAX_CANON:
  52 #ifdef  MAX_CANON
  53       return MAX_CANON;
  54 #else
  55       return -1;
  56 #endif
  57
  58     case _PC_MAX_INPUT:
  59 #ifdef  MAX_INPUT
  60       return MAX_INPUT;
  61 #else
  62       return -1;
  63 #endif
  64
  65     case _PC_NAME_MAX:
  66 #ifdef  NAME_MAX
  67       {
  68         struct statfs buf;
  69         int save_errno = errno;
  70
  71         if (__statfs (path, &buf) < 0)
  72           {
  73             if (errno == ENOSYS)
  74               {
  75                 errno = save_errno;
  76                 return NAME_MAX;
  77               }
  78             return -1;
  79           }
  80         else
  81           {
  82 #ifdef _STATFS_F_NAMELEN
  83             return buf.f_namelen;
  84 #else
  85 # ifdef _STATFS_F_NAME_MAX
  86             return buf.f_name_max;
  87 # else
  88             return NAME_MAX;
  89 # endif
  90 #endif
  91           }
  92       }
  93 #else
  94       return -1;
  95 #endif
  96
  97     case _PC_PATH_MAX:
  98 #ifdef  PATH_MAX
  99       return PATH_MAX;
 100 #else
 101       return -1;
 102 #endif
 103
 104     case _PC_PIPE_BUF:
 105 #ifdef  PIPE_BUF
 106       return PIPE_BUF;
 107 #else
 108       return -1;
 109 #endif
 110
 111     case _PC_CHOWN_RESTRICTED:
 112 #ifdef  _POSIX_CHOWN_RESTRICTED
 113       return _POSIX_CHOWN_RESTRICTED;
 114 #else
 115       return -1;
 116 #endif
 117
 118     case _PC_NO_TRUNC:
 119 #ifdef  _POSIX_NO_TRUNC
 120       return _POSIX_NO_TRUNC;
 121 #else
 122       return -1;
 123 #endif
 124
 125     case _PC_VDISABLE:
 126 #ifdef  _POSIX_VDISABLE
 127       return _POSIX_VDISABLE;
 128 #else
 129       return -1;
 130 #endif
 131
 132     case _PC_SYNC_IO:
 133 #ifdef  _POSIX_SYNC_IO
 134       return _POSIX_SYNC_IO;
 135 #else
 136       return -1;
 137 #endif
 138
 139     case _PC_ASYNC_IO:
 140 #ifdef  _POSIX_ASYNC_IO
 141       {
 142         /* AIO is only allowed on regular files and block devices.  */
 143         struct stat64 st;
 144
 145         if (__xstat64 (_STAT_VER, path, &st) < 0
 146             || (! S_ISREG (st.st_mode) && ! S_ISBLK (st.st_mode)))
 147           return -1;
 148         else
 149           return 1;
 150       }
 151 #else
 152       return -1;
 153 #endif
 154
 155     case _PC_PRIO_IO:
 156 #ifdef  _POSIX_PRIO_IO
 157       return _POSIX_PRIO_IO;
 158 #else
 159       return -1;
 160 #endif
 161
 162     case _PC_SOCK_MAXBUF:
 163 #ifdef  SOCK_MAXBUF
 164       return SOCK_MAXBUF;
 165 #else
 166       return -1;
 167 #endif
 168
 169     case _PC_FILESIZEBITS:
 170 #ifdef FILESIZEBITS
 171       return FILESIZEBITS;
 172 #else
 173       /* We let platforms with larger file sizes overwrite this value.  */
 174       return 32;
 175 #endif
 176
 177     case _PC_REC_INCR_XFER_SIZE:
 178       /* XXX It is not entirely clear what the limit is supposed to do.
 179          What is incremented?  */
 180       return -1;
 181
 182     case _PC_REC_MAX_XFER_SIZE:
 183       /* XXX It is not entirely clear what the limit is supposed to do.
 184          In general there is no top limit of the number of bytes which
 185          case be transported at once.  */
 186       return -1;
 187
 188     case _PC_REC_MIN_XFER_SIZE:
 189       {
 190         /* XXX It is not entirely clear what the limit is supposed to do.
 191            I assume this is the block size of the filesystem.  */
 192         struct statvfs64 sv;
 193
 194         if (__statvfs64 (path, &sv) < 0)
 195           return -1;
 196         return sv.f_bsize;
 197       }
 198
 199     case _PC_REC_XFER_ALIGN:
 200       {
 201         /* XXX It is not entirely clear what the limit is supposed to do.
 202            I assume that the number should reflect the minimal block
 203            alignment.  */
 204         struct statvfs64 sv;
 205
 206         if (__statvfs64 (path, &sv) < 0)
 207           return -1;
 208         return sv.f_frsize;
 209       }
 210
 211     case _PC_ALLOC_SIZE_MIN:
 212       {
 213         /* XXX It is not entirely clear what the limit is supposed to do.
 214            I assume that the number should reflect the minimal block
 215            alignment.  */
 216         struct statvfs64 sv;
 217
 218         if (__statvfs64 (path, &sv) < 0)
 219           return -1;
 220         return sv.f_frsize;
 221       }
 222
 223     case _PC_SYMLINK_MAX:
 224       /* In general there are no limits.  If a system has one it should
 225          overwrite this case.  */
 226       return -1;
 227
 228     case _PC_2_SYMLINKS:
 229       /* Unix systems generally have symlinks.  */
 230       return 1;
 231     }
 232 }
 233
 234 #undef __pathconf
 235 weak_alias (__pathconf, pathconf)