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 #define STAT stat64
  28 #define FSTAT fstat64
  29
  30 #ifndef __USE_FILE_OFFSET64
  31 extern int fstatfs (int __fildes, struct statfs *__buf)
  32      __THROW __nonnull ((2));
  33 #else
  34 # ifdef __REDIRECT_NTH
  35          extern int __REDIRECT_NTH (fstatfs, (int __fildes, struct statfs *__buf),
  36                                     fstatfs64) __nonnull ((2));
  37 # else
  38 #  define fstatfs fstatfs64
  39 # endif
  40 #endif
  41
  42 extern __typeof(fstatfs) __libc_fstatfs;
  43
  44 /* The Linux kernel headers mention this as a kind of generic value.  */
  45 #define LINUX_LINK_MAX  127
  46
  47
  48 /* Get file-specific information about descriptor FD.  */
  49 long int fpathconf(int fd, int name)
  50 {
  51     if (fd < 0)
  52     {
  53         __set_errno (EBADF);
  54         return -1;
  55     }
  56
  57     if (name == _PC_LINK_MAX)
  58     {
  59         /* Cut some corners */
  60 #if 0
  61         struct statfs fsbuf;
  62
  63         /* Determine the filesystem type.  */
  64         if (__libc_fstatfs (fd, &fsbuf) < 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             default:
 105                 return LINUX_LINK_MAX;
 106         }
 107 #else
 108         return LINUX_LINK_MAX;
 109 #endif
 110     }
 111
 112     switch (name)
 113     {
 114         default:
 115             __set_errno (EINVAL);
 116             return -1;
 117
 118         case _PC_MAX_CANON:
 119 #ifdef  MAX_CANON
 120             return MAX_CANON;
 121 #else
 122             return -1;
 123 #endif
 124
 125         case _PC_MAX_INPUT:
 126 #ifdef  MAX_INPUT
 127             return MAX_INPUT;
 128 #else
 129             return -1;
 130 #endif
 131
 132         case _PC_NAME_MAX:
 133 #ifdef  NAME_MAX
 134             {
 135                 struct statfs buf;
 136                 int save_errno = errno;
 137
 138                 if (__libc_fstatfs (fd, &buf) < 0)
 139                 {
 140                     if (errno == ENOSYS)
 141                     {
 142                         errno = save_errno;
 143                         return NAME_MAX;
 144                     }
 145                     return -1;
 146                 }
 147                 else
 148                 {
 149 #ifdef _STATFS_F_NAMELEN
 150                     return buf.f_namelen;
 151 #else
 152 # ifdef _STATFS_F_NAME_MAX
 153                     return buf.f_name_max;
 154 # else
 155                     return NAME_MAX;
 156 # endif
 157 #endif
 158                 }
 159             }
 160 #else
 161             return -1;
 162 #endif
 163
 164         case _PC_PATH_MAX:
 165 #ifdef  PATH_MAX
 166             return PATH_MAX;
 167 #else
 168             return -1;
 169 #endif
 170
 171         case _PC_PIPE_BUF:
 172 #ifdef  PIPE_BUF
 173             return PIPE_BUF;
 174 #else
 175             return -1;
 176 #endif
 177
 178         case _PC_CHOWN_RESTRICTED:
 179 #ifdef  _POSIX_CHOWN_RESTRICTED
 180             return _POSIX_CHOWN_RESTRICTED;
 181 #else
 182             return -1;
 183 #endif
 184
 185         case _PC_NO_TRUNC:
 186 #ifdef  _POSIX_NO_TRUNC
 187             return _POSIX_NO_TRUNC;
 188 #else
 189             return -1;
 190 #endif
 191
 192         case _PC_VDISABLE:
 193 #ifdef  _POSIX_VDISABLE
 194             return _POSIX_VDISABLE;
 195 #else
 196             return -1;
 197 #endif
 198
 199         case _PC_SYNC_IO:
 200 #ifdef  _POSIX_SYNC_IO
 201             return _POSIX_SYNC_IO;
 202 #else
 203             return -1;
 204 #endif
 205
 206         case _PC_ASYNC_IO:
 207 #if defined _POSIX_ASYNC_IO
 208             {
 209                 /* AIO is only allowed on regular files and block devices.  */
 210                 struct STAT st;
 211
 212                 if (FSTAT (fd, &st) < 0 || (! S_ISREG (st.st_mode) && ! S_ISBLK (st.st_mode)))
 213                     return -1;
 214                 else
 215                     return 1;
 216             }
 217 #else
 218             return -1;
 219 #endif
 220
 221         case _PC_PRIO_IO:
 222 #ifdef  _POSIX_PRIO_IO
 223             return _POSIX_PRIO_IO;
 224 #else
 225             return -1;
 226 #endif
 227
 228         case _PC_SOCK_MAXBUF:
 229 #ifdef  SOCK_MAXBUF
 230             return SOCK_MAXBUF;
 231 #else
 232             return -1;
 233 #endif
 234
 235         case _PC_FILESIZEBITS:
 236 #ifdef FILESIZEBITS
 237             return FILESIZEBITS;
 238 #else
 239             /* We let platforms with larger file sizes overwrite this value.  */
 240             return 32;
 241 #endif
 242
 243             /* Be lazy -- skip these */
 244         case _PC_REC_INCR_XFER_SIZE:
 245         case _PC_REC_MAX_XFER_SIZE:
 246         case _PC_REC_MIN_XFER_SIZE:
 247         case _PC_REC_XFER_ALIGN:
 248         case _PC_ALLOC_SIZE_MIN:
 249         case _PC_SYMLINK_MAX:
 250             return -1;
 251     }
 252
 253 }
 254