hurd/hurdlookup.c

   1 /* Copyright (C) 1992,93,94,95,96,97,99,2001 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, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <hurd.h>
  20 #include <hurd/lookup.h>
  21 #include <string.h>
  22 #include <fcntl.h>
  23
  24
  25 /* Translate the error from dir_lookup into the error the user sees.  */
  26 static inline error_t
  27 lookup_error (error_t error)
  28 {
  29   switch (error)
  30     {
  31     case EOPNOTSUPP:
  32     case MIG_BAD_ID:
  33       /* These indicate that the server does not understand dir_lookup
  34          at all.  If it were a directory, it would, by definition.  */
  35       return ENOTDIR;
  36     default:
  37       return error;
  38     }
  39 }
  40
  41 error_t
  42 __hurd_file_name_lookup (error_t (*use_init_port)
  43                            (int which, error_t (*operate) (file_t)),
  44                          file_t (*get_dtable_port) (int fd),
  45                          error_t (*lookup)
  46                            (file_t dir, char *name, int flags, mode_t mode,
  47                             retry_type *do_retry, string_t retry_name,
  48                             mach_port_t *result),
  49                          const char *file_name, int flags, mode_t mode,
  50                          file_t *result)
  51 {
  52   error_t err;
  53   enum retry_type doretry;
  54   char retryname[1024];         /* XXX string_t LOSES! */
  55   int startport;
  56
  57   error_t lookup_op (mach_port_t startdir)
  58     {
  59       return lookup_error ((*lookup) (startdir, file_name, flags, mode,
  60                                       &doretry, retryname, result));
  61     }
  62
  63   if (! lookup)
  64     lookup = __dir_lookup;
  65
  66   startport = (file_name[0] == '/') ? INIT_PORT_CRDIR : INIT_PORT_CWDIR;
  67   while (file_name[0] == '/')
  68     file_name++;
  69
  70   if (flags & O_NOFOLLOW)       /* See comments below about O_NOFOLLOW.  */
  71     flags |= O_NOTRANS;
  72
  73   if (flags & O_DIRECTORY)
  74     {
  75       /* The caller wants to require that the file we look up is a directory.
  76          We can do this without an extra RPC by appending a trailing slash
  77          to the file name we look up.  */
  78       size_t len = strlen (file_name);
  79       if (len == 0)
  80         file_name = "/";
  81       else if (file_name[len - 1] != '/')
  82         {
  83           char *n = alloca (len + 2);
  84           memcpy (n, file_name, len);
  85           n[len] = '/';
  86           n[len + 1] = '\0';
  87           file_name = n;
  88         }
  89     }
  90
  91   err = (*use_init_port) (startport, &lookup_op);
  92   if (! err)
  93     err = __hurd_file_name_lookup_retry (use_init_port, get_dtable_port,
  94                                          lookup, doretry, retryname,
  95                                          flags, mode, result);
  96
  97   return err;
  98 }
  99 weak_alias (__hurd_file_name_lookup, hurd_file_name_lookup)
 100
 101 error_t
 102 __hurd_file_name_split (error_t (*use_init_port)
 103                           (int which, error_t (*operate) (file_t)),
 104                         file_t (*get_dtable_port) (int fd),
 105                         error_t (*lookup)
 106                           (file_t dir, char *name, int flags, mode_t mode,
 107                            retry_type *do_retry, string_t retry_name,
 108                            mach_port_t *result),
 109                         const char *file_name,
 110                         file_t *dir, char **name)
 111 {
 112   error_t addref (file_t crdir)
 113     {
 114       *dir = crdir;
 115       return __mach_port_mod_refs (__mach_task_self (),
 116                                    crdir, MACH_PORT_RIGHT_SEND, +1);
 117     }
 118
 119   const char *lastslash = strrchr (file_name, '/');
 120
 121   if (lastslash != NULL)
 122     {
 123       if (lastslash == file_name)
 124         {
 125           /* "/foobar" => crdir + "foobar".  */
 126           *name = (char *) file_name + 1;
 127           return (*use_init_port) (INIT_PORT_CRDIR, &addref);
 128         }
 129       else
 130         {
 131           /* "/dir1/dir2/.../file".  */
 132           char dirname[lastslash - file_name + 1];
 133           memcpy (dirname, file_name, lastslash - file_name);
 134           dirname[lastslash - file_name] = '\0';
 135           *name = (char *) lastslash + 1;
 136           return
 137             __hurd_file_name_lookup (use_init_port, get_dtable_port, lookup,
 138                                      dirname, 0, 0, dir);
 139         }
 140     }
 141   else
 142     {
 143       /* "foobar" => cwdir + "foobar".  */
 144       *name = (char *) file_name;
 145       return (*use_init_port) (INIT_PORT_CWDIR, &addref);
 146     }
 147 }
 148 weak_alias (__hurd_file_name_split, hurd_file_name_split)
 149
 150 /* This is the same as hurd_file_name_split, except that it ignores
 151    trailing slashes (so *NAME is never "").  */
 152 error_t
 153 __hurd_directory_name_split (error_t (*use_init_port)
 154                              (int which, error_t (*operate) (file_t)),
 155                              file_t (*get_dtable_port) (int fd),
 156                              error_t (*lookup)
 157                              (file_t dir, char *name, int flags, mode_t mode,
 158                               retry_type *do_retry, string_t retry_name,
 159                               mach_port_t *result),
 160                              const char *file_name,
 161                              file_t *dir, char **name)
 162 {
 163   error_t addref (file_t crdir)
 164     {
 165       *dir = crdir;
 166       return __mach_port_mod_refs (__mach_task_self (),
 167                                    crdir, MACH_PORT_RIGHT_SEND, +1);
 168     }
 169
 170   const char *lastslash = strrchr (file_name, '/');
 171
 172   if (lastslash != NULL && lastslash[1] == '\0')
 173     {
 174       /* Trailing slash doesn't count.  Look back further.  */
 175
 176       /* Back up over all trailing slashes.  */
 177       while (lastslash > file_name && *lastslash == '/')
 178         --lastslash;
 179
 180       /* Find the last one earlier in the string, before the trailing ones.  */
 181 #if __GLIBC__ > 2 || __GLIBC_MINOR__ >= 2
 182       lastslash = __memrchr (file_name, '/', lastslash - file_name);
 183 #else
 184       /* Keep backing up, looking for a slash.  */
 185       do
 186         if (lastslash == file_name)
 187           {
 188             /* Hit the start with no slash.  */
 189             lastslash = NULL;
 190             break;
 191           }
 192       while (*lastslash-- != '/');
 193 #endif
 194     }
 195
 196   if (lastslash != NULL)
 197     {
 198       if (lastslash == file_name)
 199         {
 200           /* "/foobar" => crdir + "foobar".  */
 201           *name = (char *) file_name + 1;
 202           return (*use_init_port) (INIT_PORT_CRDIR, &addref);
 203         }
 204       else
 205         {
 206           /* "/dir1/dir2/.../file".  */
 207           char dirname[lastslash - file_name + 1];
 208           memcpy (dirname, file_name, lastslash - file_name);
 209           dirname[lastslash - file_name] = '\0';
 210           *name = (char *) lastslash + 1;
 211           return
 212             __hurd_file_name_lookup (use_init_port, get_dtable_port, lookup,
 213                                      dirname, 0, 0, dir);
 214         }
 215     }
 216   else
 217     {
 218       /* "foobar" => cwdir + "foobar".  */
 219       *name = (char *) file_name;
 220       return (*use_init_port) (INIT_PORT_CWDIR, &addref);
 221     }
 222 }
 223 weak_alias (__hurd_directory_name_split, hurd_directory_name_split)
 224
 225 \f
 226 file_t
 227 __file_name_lookup (const char *file_name, int flags, mode_t mode)
 228 {
 229   error_t err;
 230   file_t result;
 231
 232   err = __hurd_file_name_lookup (&_hurd_ports_use, &__getdport, 0,
 233                                  file_name, flags, mode & ~_hurd_umask,
 234                                  &result);
 235
 236   return err ? (__hurd_fail (err), MACH_PORT_NULL) : result;
 237 }
 238 weak_alias (__file_name_lookup, file_name_lookup)
 239
 240
 241 file_t
 242 __file_name_split (const char *file_name, char **name)
 243 {
 244   error_t err;
 245   file_t result;
 246
 247   err = __hurd_file_name_split (&_hurd_ports_use, &__getdport, 0,
 248                                 file_name, &result, name);
 249
 250   return err ? (__hurd_fail (err), MACH_PORT_NULL) : result;
 251 }
 252 weak_alias (__file_name_split, file_name_split)
 253
 254 file_t
 255 __directory_name_split (const char *directory_name, char **name)
 256 {
 257   error_t err;
 258   file_t result;
 259
 260   err = __hurd_directory_name_split (&_hurd_ports_use, &__getdport, 0,
 261                                      directory_name, &result, name);
 262
 263   return err ? (__hurd_fail (err), MACH_PORT_NULL) : result;
 264 }
 265 weak_alias (__directory_name_split, directory_name_split)
 266
 267
 268 file_t
 269 __file_name_lookup_under (file_t startdir,
 270                           const char *file_name, int flags, mode_t mode)
 271 {
 272   error_t err;
 273   file_t result;
 274
 275   error_t use_init_port (int which, error_t (*operate) (mach_port_t))
 276     {
 277       return (which == INIT_PORT_CWDIR ? (*operate) (startdir) :
 278               _hurd_ports_use (which, operate));
 279     }
 280
 281   err = __hurd_file_name_lookup (&use_init_port, &__getdport, 0,
 282                                  file_name, flags, mode & ~_hurd_umask,
 283                                  &result);
 284
 285   return err ? (__hurd_fail (err), MACH_PORT_NULL) : result;
 286 }
 287 weak_alias (__file_name_lookup_under, file_name_lookup_under)