sysdeps/unix/sysv/linux/pathconf.c

   1 /* Get file-specific information about a file.  Linux version.
   2    Copyright (C) 1991,1995,1996,1998-2003,2008 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 <unistd.h>
  21 #include <errno.h>
  22
  23 #include "pathconf.h"
  24 #include "linux_fsinfo.h"
  25 #include <not-cancel.h>
  26
  27 static long int posix_pathconf (const char *file, int name);
  28
  29 /* Define this first, so it can be inlined.  */
  30 #define __pathconf static posix_pathconf
  31 #include <sysdeps/posix/pathconf.c>
  32
  33
  34 /* Get file-specific information about FILE.  */
  35 long int
  36 __pathconf (const char *file, int name)
  37 {
  38   struct statfs fsbuf;
  39
  40   switch (name)
  41     {
  42     case _PC_LINK_MAX:
  43       return __statfs_link_max (__statfs (file, &fsbuf), &fsbuf);
  44
  45     case _PC_FILESIZEBITS:
  46       return __statfs_filesize_max (__statfs (file, &fsbuf), &fsbuf);
  47
  48     case _PC_2_SYMLINKS:
  49       return __statfs_symlinks (__statfs (file, &fsbuf), &fsbuf);
  50
  51     case _PC_CHOWN_RESTRICTED:
  52       return __statfs_chown_restricted (__statfs (file, &fsbuf), &fsbuf);
  53
  54     default:
  55       return posix_pathconf (file, name);
  56     }
  57 }
  58
  59
  60 /* Used like: return statfs_link_max (__statfs (name, &buf), &buf); */
  61 long int
  62 __statfs_link_max (int result, const struct statfs *fsbuf)
  63 {
  64   if (result < 0)
  65     {
  66       if (errno == ENOSYS)
  67         /* Not possible, return the default value.  */
  68         return LINUX_LINK_MAX;
  69
  70       /* Some error occured.  */
  71       return -1;
  72     }
  73
  74   switch (fsbuf->f_type)
  75     {
  76     case EXT2_SUPER_MAGIC:
  77       return EXT2_LINK_MAX;
  78
  79     case MINIX_SUPER_MAGIC:
  80     case MINIX_SUPER_MAGIC2:
  81       return MINIX_LINK_MAX;
  82
  83     case MINIX2_SUPER_MAGIC:
  84     case MINIX2_SUPER_MAGIC2:
  85       return MINIX2_LINK_MAX;
  86
  87     case XENIX_SUPER_MAGIC:
  88       return XENIX_LINK_MAX;
  89
  90     case SYSV4_SUPER_MAGIC:
  91     case SYSV2_SUPER_MAGIC:
  92       return SYSV_LINK_MAX;
  93
  94     case COH_SUPER_MAGIC:
  95       return COH_LINK_MAX;
  96
  97     case UFS_MAGIC:
  98     case UFS_CIGAM:
  99       return UFS_LINK_MAX;
 100
 101     case REISERFS_SUPER_MAGIC:
 102       return REISERFS_LINK_MAX;
 103
 104     case XFS_SUPER_MAGIC:
 105       return XFS_LINK_MAX;
 106
 107     default:
 108       return LINUX_LINK_MAX;
 109     }
 110 }
 111
 112
 113 /* Used like: return statfs_filesize_max (__statfs (name, &buf), &buf); */
 114 long int
 115 __statfs_filesize_max (int result, const struct statfs *fsbuf)
 116 {
 117   if (result < 0)
 118     {
 119       if (errno == ENOSYS)
 120         /* Not possible, return the default value.  */
 121         return 32;
 122
 123       /* Some error occured.  */
 124       return -1;
 125     }
 126
 127   switch (fsbuf->f_type)
 128     {
 129     case EXT2_SUPER_MAGIC:
 130     case UFS_MAGIC:
 131     case UFS_CIGAM:
 132     case REISERFS_SUPER_MAGIC:
 133     case XFS_SUPER_MAGIC:
 134     case SMB_SUPER_MAGIC:
 135     case NTFS_SUPER_MAGIC:
 136     case UDF_SUPER_MAGIC:
 137     case JFS_SUPER_MAGIC:
 138     case VXFS_SUPER_MAGIC:
 139       return 64;
 140
 141     case MSDOS_SUPER_MAGIC:
 142     case JFFS_SUPER_MAGIC:
 143     case JFFS2_SUPER_MAGIC:
 144     case NCP_SUPER_MAGIC:
 145     case ROMFS_SUPER_MAGIC:
 146       return 32;
 147
 148     default:
 149       return 32;
 150     }
 151 }
 152
 153
 154 /* Used like: return statfs_link_max (__statfs (name, &buf), &buf); */
 155 long int
 156 __statfs_symlinks (int result, const struct statfs *fsbuf)
 157 {
 158   if (result < 0)
 159     {
 160       if (errno == ENOSYS)
 161         /* Not possible, return the default value.  */
 162         return 1;
 163
 164       /* Some error occured.  */
 165       return -1;
 166     }
 167
 168   switch (fsbuf->f_type)
 169     {
 170     case ADFS_SUPER_MAGIC:
 171     case BFS_MAGIC:
 172     case CRAMFS_MAGIC:
 173     case DEVPTS_SUPER_MAGIC:
 174     case EFS_SUPER_MAGIC:
 175     case EFS_MAGIC:
 176     case MSDOS_SUPER_MAGIC:
 177     case NTFS_SUPER_MAGIC:
 178     case QNX4_SUPER_MAGIC:
 179     case ROMFS_SUPER_MAGIC:
 180       /* No symlink support.  */
 181       return 0;
 182
 183     default:
 184       return 1;
 185     }
 186 }
 187
 188
 189 /* Used like: return __statfs_chown_restricted (__statfs (name, &buf), &buf);*/
 190 long int
 191 __statfs_chown_restricted (int result, const struct statfs *fsbuf)
 192 {
 193   if (result < 0)
 194     {
 195       if (errno == ENOSYS)
 196         /* Not possible, return the default value.  */
 197         return 1;
 198
 199       /* Some error occured.  */
 200       return -1;
 201     }
 202
 203   int fd;
 204   long int retval = 1;
 205   switch (fsbuf->f_type)
 206     {
 207     case XFS_SUPER_MAGIC:
 208       /* Read the value from /proc/sys/fs/xfs/restrict_chown.  If we cannot
 209          read it default to assume the restriction is in place.  */
 210       fd = open_not_cancel_2 ("/proc/sys/fs/xfs/restrict_chown", O_RDONLY);
 211       if (fd != -1)
 212         {
 213           char buf[2];
 214           if (TEMP_FAILURE_RETRY (read_not_cancel (fd, buf, 2)) == 2
 215               && buf[0] >= '0' && buf[0] <= '1')
 216             retval = buf[0] - '0';
 217
 218           close_not_cancel_no_status (fd);
 219         }
 220       break;
 221
 222     default:
 223       break;
 224     }
 225
 226   return retval;
 227 }