libc/unistd/fpathconf.c

   1 /* fpathconf -- adjusted for busybox
   2    Copyright (C) 1991,95,96,98,99,2000,2001 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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <unistd.h>
  21 #include <limits.h>
  22 #include <stddef.h>
  23 #include <fcntl.h>
  24 #include <sys/stat.h>
  25 #include <sys/statfs.h>
  26
  27
  28 #ifndef __USE_FILE_OFFSET64
  29 extern int fstatfs (int __fildes, struct statfs *__buf)
  30      __THROW __nonnull ((2));
  31 #else
  32 # ifdef __REDIRECT_NTH
  33          extern int __REDIRECT_NTH (fstatfs, (int __fildes, struct statfs *__buf),
  34                                     fstatfs64) __nonnull ((2));
  35 # else
  36 #  define fstatfs fstatfs64
  37 # endif
  38 #endif
  39
  40 extern __typeof(fstatfs) __libc_fstatfs;
  41
  42 /* The Linux kernel headers mention this as a kind of generic value.  */
  43 #define LINUX_LINK_MAX  127
  44
  45
  46 /* Get file-specific information about descriptor FD.  */
  47 long int fpathconf(int fd, int name)
  48 {
  49     if (fd < 0)
  50     {
  51         __set_errno (EBADF);
  52         return -1;
  53     }
  54
  55     if (name == _PC_LINK_MAX)
  56     {
  57         /* Cut some corners */
  58 #if 0
  59         struct statfs fsbuf;
  60
  61         /* Determine the filesystem type.  */
  62         if (__libc_fstatfs (fd, &fsbuf) < 0)
  63         {
  64             if (errno == ENOSYS)
  65                 /* not possible, return the default value.  */
  66                 return LINUX_LINK_MAX;
  67
  68             /* Some error occured.  */
  69             return -1;
  70         }
  71
  72         switch (fsbuf.f_type)
  73         {
  74             case EXT2_SUPER_MAGIC:
  75                 return EXT2_LINK_MAX;
  76
  77             case MINIX_SUPER_MAGIC:
  78             case MINIX_SUPER_MAGIC2:
  79                 return MINIX_LINK_MAX;
  80
  81             case MINIX2_SUPER_MAGIC:
  82             case MINIX2_SUPER_MAGIC2:
  83                 return MINIX2_LINK_MAX;
  84
  85             case XENIX_SUPER_MAGIC:
  86                 return XENIX_LINK_MAX;
  87
  88             case SYSV4_SUPER_MAGIC:
  89             case SYSV2_SUPER_MAGIC:
  90                 return SYSV_LINK_MAX;
  91
  92             case COH_SUPER_MAGIC:
  93                 return COH_LINK_MAX;
  94
  95             case UFS_MAGIC:
  96             case UFS_CIGAM:
  97                 return UFS_LINK_MAX;
  98
  99             case REISERFS_SUPER_MAGIC:
 100                 return REISERFS_LINK_MAX;
 101
 102             default:
 103                 return LINUX_LINK_MAX;
 104         }
 105 #else
 106         return LINUX_LINK_MAX;
 107 #endif
 108     }
 109
 110     switch (name)
 111     {
 112         default:
 113             __set_errno (EINVAL);
 114             return -1;
 115
 116         case _PC_MAX_CANON:
 117 #ifdef  MAX_CANON
 118             return MAX_CANON;
 119 #else
 120             return -1;
 121 #endif
 122
 123         case _PC_MAX_INPUT:
 124 #ifdef  MAX_INPUT
 125             return MAX_INPUT;
 126 #else
 127             return -1;
 128 #endif
 129
 130         case _PC_NAME_MAX:
 131 #ifdef  NAME_MAX
 132             {
 133                 struct statfs buf;
 134                 int save_errno = errno;
 135
 136                 if (__libc_fstatfs (fd, &buf) < 0)
 137                 {
 138                     if (errno == ENOSYS)
 139                     {
 140                         errno = save_errno;
 141                         return NAME_MAX;
 142                     }
 143                     return -1;
 144                 }
 145                 else
 146                 {
 147 #ifdef _STATFS_F_NAMELEN
 148                     return buf.f_namelen;
 149 #else
 150 # ifdef _STATFS_F_NAME_MAX
 151                     return buf.f_name_max;
 152 # else
 153                     return NAME_MAX;
 154 # endif
 155 #endif
 156                 }
 157             }
 158 #else
 159             return -1;
 160 #endif
 161
 162         case _PC_PATH_MAX:
 163 #ifdef  PATH_MAX
 164             return PATH_MAX;
 165 #else
 166             return -1;
 167 #endif
 168
 169         case _PC_PIPE_BUF:
 170 #ifdef  PIPE_BUF
 171             return PIPE_BUF;
 172 #else
 173             return -1;
 174 #endif
 175
 176         case _PC_CHOWN_RESTRICTED:
 177 #ifdef  _POSIX_CHOWN_RESTRICTED
 178             return _POSIX_CHOWN_RESTRICTED;
 179 #else
 180             return -1;
 181 #endif
 182
 183         case _PC_NO_TRUNC:
 184 #ifdef  _POSIX_NO_TRUNC
 185             return _POSIX_NO_TRUNC;
 186 #else
 187             return -1;
 188 #endif
 189
 190         case _PC_VDISABLE:
 191 #ifdef  _POSIX_VDISABLE
 192             return _POSIX_VDISABLE;
 193 #else
 194             return -1;
 195 #endif
 196
 197         case _PC_SYNC_IO:
 198 #ifdef  _POSIX_SYNC_IO
 199             return _POSIX_SYNC_IO;
 200 #else
 201             return -1;
 202 #endif
 203
 204         case _PC_ASYNC_IO:
 205 #if defined _POSIX_ASYNC_IO
 206             {
 207                 /* AIO is only allowed on regular files and block devices.  */
 208                 struct stat st;
 209
 210                 if (fstat (fd, &st) < 0 || (! S_ISREG (st.st_mode) && ! S_ISBLK (st.st_mode)))
 211                     return -1;
 212                 else
 213                     return 1;
 214             }
 215 #else
 216             return -1;
 217 #endif
 218
 219         case _PC_PRIO_IO:
 220 #ifdef  _POSIX_PRIO_IO
 221             return _POSIX_PRIO_IO;
 222 #else
 223             return -1;
 224 #endif
 225
 226         case _PC_SOCK_MAXBUF:
 227 #ifdef  SOCK_MAXBUF
 228             return SOCK_MAXBUF;
 229 #else
 230             return -1;
 231 #endif
 232
 233         case _PC_FILESIZEBITS:
 234 #ifdef FILESIZEBITS
 235             return FILESIZEBITS;
 236 #else
 237             /* We let platforms with larger file sizes overwrite this value.  */
 238             return 32;
 239 #endif
 240
 241             /* Be lazy -- skip these */
 242         case _PC_REC_INCR_XFER_SIZE:
 243         case _PC_REC_MAX_XFER_SIZE:
 244         case _PC_REC_MIN_XFER_SIZE:
 245         case _PC_REC_XFER_ALIGN:
 246         case _PC_ALLOC_SIZE_MIN:
 247         case _PC_SYMLINK_MAX:
 248             return -1;
 249     }
 250
 251 }
 252