sysdeps/posix/pathconf.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 <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 statvfs64 sv;
  69         int save_errno = errno;
  70
  71         if (__statvfs64 (path, &sv) < 0)
  72           {
  73             if (errno == ENOSYS)
  74               {
  75                 errno = save_errno;
  76                 return NAME_MAX;
  77               }
  78             return -1;
  79           }
  80         else
  81           {
  82             return sv.f_namemax;
  83           }
  84       }
  85 #else
  86       return -1;
  87 #endif
  88
  89     case _PC_PATH_MAX:
  90 #ifdef  PATH_MAX
  91       return PATH_MAX;
  92 #else
  93       return -1;
  94 #endif
  95
  96     case _PC_PIPE_BUF:
  97 #ifdef  PIPE_BUF
  98       return PIPE_BUF;
  99 #else
 100       return -1;
 101 #endif
 102
 103     case _PC_CHOWN_RESTRICTED:
 104 #ifdef  _POSIX_CHOWN_RESTRICTED
 105       return _POSIX_CHOWN_RESTRICTED;
 106 #else
 107       return -1;
 108 #endif
 109
 110     case _PC_NO_TRUNC:
 111 #ifdef  _POSIX_NO_TRUNC
 112       return _POSIX_NO_TRUNC;
 113 #else
 114       return -1;
 115 #endif
 116
 117     case _PC_VDISABLE:
 118 #ifdef  _POSIX_VDISABLE
 119       return _POSIX_VDISABLE;
 120 #else
 121       return -1;
 122 #endif
 123
 124     case _PC_SYNC_IO:
 125 #ifdef  _POSIX_SYNC_IO
 126       return _POSIX_SYNC_IO;
 127 #else
 128       return -1;
 129 #endif
 130
 131     case _PC_ASYNC_IO:
 132 #ifdef  _POSIX_ASYNC_IO
 133       {
 134         /* AIO is only allowed on regular files and block devices.  */
 135         struct stat64 st;
 136
 137         if (__xstat64 (_STAT_VER, path, &st) < 0
 138             || (! S_ISREG (st.st_mode) && ! S_ISBLK (st.st_mode)))
 139           return -1;
 140         else
 141           return 1;
 142       }
 143 #else
 144       return -1;
 145 #endif
 146
 147     case _PC_PRIO_IO:
 148 #ifdef  _POSIX_PRIO_IO
 149       return _POSIX_PRIO_IO;
 150 #else
 151       return -1;
 152 #endif
 153
 154     case _PC_SOCK_MAXBUF:
 155 #ifdef  SOCK_MAXBUF
 156       return SOCK_MAXBUF;
 157 #else
 158       return -1;
 159 #endif
 160
 161     case _PC_FILESIZEBITS:
 162 #ifdef FILESIZEBITS
 163       return FILESIZEBITS;
 164 #else
 165       /* We let platforms with larger file sizes overwrite this value.  */
 166       return 32;
 167 #endif
 168
 169     case _PC_REC_INCR_XFER_SIZE:
 170       /* XXX It is not entirely clear what the limit is supposed to do.
 171          What is incremented?  */
 172       return -1;
 173
 174     case _PC_REC_MAX_XFER_SIZE:
 175       /* XXX It is not entirely clear what the limit is supposed to do.
 176          In general there is no top limit of the number of bytes which
 177          case be transported at once.  */
 178       return -1;
 179
 180     case _PC_REC_MIN_XFER_SIZE:
 181       {
 182         /* XXX It is not entirely clear what the limit is supposed to do.
 183            I assume this is the block size of the filesystem.  */
 184         struct statvfs64 sv;
 185
 186         if (__statvfs64 (path, &sv) < 0)
 187           return -1;
 188         return sv.f_bsize;
 189       }
 190
 191     case _PC_REC_XFER_ALIGN:
 192       {
 193         /* XXX It is not entirely clear what the limit is supposed to do.
 194            I assume that the number should reflect the minimal block
 195            alignment.  */
 196         struct statvfs64 sv;
 197
 198         if (__statvfs64 (path, &sv) < 0)
 199           return -1;
 200         return sv.f_frsize;
 201       }
 202
 203     case _PC_ALLOC_SIZE_MIN:
 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 (__statvfs64 (path, &sv) < 0)
 211           return -1;
 212         return sv.f_frsize;
 213       }
 214
 215     case _PC_SYMLINK_MAX:
 216       /* In general there are no limits.  If a system has one it should
 217          overwrite this case.  */
 218       return -1;
 219
 220     case _PC_2_SYMLINKS:
 221       /* Unix systems generally have symlinks.  */
 222       return 1;
 223     }
 224 }
 225
 226 #undef __pathconf
 227 weak_alias (__pathconf, pathconf)