sysdeps/posix/pathconf.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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <errno.h>
  21 #include <stddef.h>
  22 #include <unistd.h>
  23 #include <limits.h>
  24 #include <fcntl.h>
  25 #include <sys/stat.h>
  26 #include <sys/statfs.h>
  27 #include <sys/statvfs.h>
  28
  29
  30 /* Get file-specific information about PATH.  */
  31 long int
  32 __pathconf (const char *path, int name)
  33 {
  34   if (path[0] == '\0')
  35     {
  36       __set_errno (ENOENT);
  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 (__statfs (path, &buf) < 0)
  74           {
  75             if (errno == ENOSYS)
  76               {
  77                 errno = save_errno;
  78                 return NAME_MAX;
  79               }
  80             return -1;
  81           }
  82         else
  83           {
  84 #ifdef _STATFS_F_NAMELEN
  85             return buf.f_namelen;
  86 #else
  87 # ifdef _STATFS_F_NAME_MAX
  88             return buf.f_name_max;
  89 # else
  90             return NAME_MAX;
  91 # endif
  92 #endif
  93           }
  94       }
  95 #else
  96       return -1;
  97 #endif
  98
  99     case _PC_PATH_MAX:
 100 #ifdef  PATH_MAX
 101       return PATH_MAX;
 102 #else
 103       return -1;
 104 #endif
 105
 106     case _PC_PIPE_BUF:
 107 #ifdef  PIPE_BUF
 108       return PIPE_BUF;
 109 #else
 110       return -1;
 111 #endif
 112
 113     case _PC_CHOWN_RESTRICTED:
 114 #ifdef  _POSIX_CHOWN_RESTRICTED
 115       return _POSIX_CHOWN_RESTRICTED;
 116 #else
 117       return -1;
 118 #endif
 119
 120     case _PC_NO_TRUNC:
 121 #ifdef  _POSIX_NO_TRUNC
 122       return _POSIX_NO_TRUNC;
 123 #else
 124       return -1;
 125 #endif
 126
 127     case _PC_VDISABLE:
 128 #ifdef  _POSIX_VDISABLE
 129       return _POSIX_VDISABLE;
 130 #else
 131       return -1;
 132 #endif
 133
 134     case _PC_SYNC_IO:
 135 #ifdef  _POSIX_SYNC_IO
 136       return _POSIX_SYNC_IO;
 137 #else
 138       return -1;
 139 #endif
 140
 141     case _PC_ASYNC_IO:
 142 #ifdef  _POSIX_ASYNC_IO
 143       {
 144         /* AIO is only allowed on regular files and block devices.  */
 145         struct stat64 st;
 146
 147         if (__xstat64 (_STAT_VER, path, &st) < 0
 148             || (! S_ISREG (st.st_mode) && ! S_ISBLK (st.st_mode)))
 149           return -1;
 150         else
 151           return 1;
 152       }
 153 #else
 154       return -1;
 155 #endif
 156
 157     case _PC_PRIO_IO:
 158 #ifdef  _POSIX_PRIO_IO
 159       return _POSIX_PRIO_IO;
 160 #else
 161       return -1;
 162 #endif
 163
 164     case _PC_SOCK_MAXBUF:
 165 #ifdef  SOCK_MAXBUF
 166       return SOCK_MAXBUF;
 167 #else
 168       return -1;
 169 #endif
 170
 171     case _PC_FILESIZEBITS:
 172 #ifdef FILESIZEBITS
 173       return FILESIZEBITS;
 174 #else
 175       /* We let platforms with larger file sizes overwrite this value.  */
 176       return 32;
 177 #endif
 178
 179     case _PC_REC_INCR_XFER_SIZE:
 180       /* XXX It is not entirely clear what the limit is supposed to do.
 181          What is incremented?  */
 182       return -1;
 183
 184     case _PC_REC_MAX_XFER_SIZE:
 185       /* XXX It is not entirely clear what the limit is supposed to do.
 186          In general there is no top limit of the number of bytes which
 187          case be transported at once.  */
 188       return -1;
 189
 190     case _PC_REC_MIN_XFER_SIZE:
 191       {
 192         /* XXX It is not entirely clear what the limit is supposed to do.
 193            I assume this is the block size of the filesystem.  */
 194         struct statvfs64 sv;
 195
 196         if (__statvfs64 (path, &sv) < 0)
 197           return -1;
 198         return sv.f_bsize;
 199       }
 200
 201     case _PC_REC_XFER_ALIGN:
 202       {
 203         /* XXX It is not entirely clear what the limit is supposed to do.
 204            I assume that the number should reflect the minimal block
 205            alignment.  */
 206         struct statvfs64 sv;
 207
 208         if (__statvfs64 (path, &sv) < 0)
 209           return -1;
 210         return sv.f_frsize;
 211       }
 212
 213     case _PC_ALLOC_SIZE_MIN:
 214       {
 215         /* XXX It is not entirely clear what the limit is supposed to do.
 216            I assume that the number should reflect the minimal block
 217            alignment.  */
 218         struct statvfs64 sv;
 219
 220         if (__statvfs64 (path, &sv) < 0)
 221           return -1;
 222         return sv.f_frsize;
 223       }
 224
 225     case _PC_SYMLINK_MAX:
 226       /* In general there are no limits.  If a system has one it should
 227          overwrite this case.  */
 228       return -1;
 229
 230     case _PC_2_SYMLINKS:
 231       /* Unix systems generally have symlinks.  */
 232       return 1;
 233     }
 234 }
 235
 236 #undef __pathconf
 237 weak_alias (__pathconf, pathconf)