hurd/hurdlookup.c

   1 /* Copyright (C) 1992,93,94,95,96,97,99,2001,2004
   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 <hurd.h>
  21 #include <hurd/lookup.h>
  22 #include <string.h>
  23 #include <fcntl.h>
  24
  25
  26 /* Translate the error from dir_lookup into the error the user sees.  */
  27 static inline error_t
  28 lookup_error (error_t error)
  29 {
  30   switch (error)
  31     {
  32     case EOPNOTSUPP:
  33     case MIG_BAD_ID:
  34       /* These indicate that the server does not understand dir_lookup
  35          at all.  If it were a directory, it would, by definition.  */
  36       return ENOTDIR;
  37     default:
  38       return error;
  39     }
  40 }
  41
  42 error_t
  43 __hurd_file_name_lookup (error_t (*use_init_port)
  44                            (int which, error_t (*operate) (file_t)),
  45                          file_t (*get_dtable_port) (int fd),
  46                          error_t (*lookup)
  47                            (file_t dir, char *name, int flags, mode_t mode,
  48                             retry_type *do_retry, string_t retry_name,
  49                             mach_port_t *result),
  50                          const char *file_name, int flags, mode_t mode,
  51                          file_t *result)
  52 {
  53   error_t err;
  54   enum retry_type doretry;
  55   char retryname[1024];         /* XXX string_t LOSES! */
  56   int startport;
  57
  58   error_t lookup_op (mach_port_t startdir)
  59     {
  60       return lookup_error ((*lookup) (startdir, file_name, flags, mode,
  61                                       &doretry, retryname, result));
  62     }
  63
  64   if (! lookup)
  65     lookup = __dir_lookup;
  66
  67   if (file_name[0] == '\0')
  68     return ENOENT;
  69
  70   startport = (file_name[0] == '/') ? INIT_PORT_CRDIR : INIT_PORT_CWDIR;
  71   while (file_name[0] == '/')
  72     file_name++;
  73
  74   if (flags & O_NOFOLLOW)       /* See lookup-retry.c about O_NOFOLLOW.  */
  75     flags |= O_NOTRANS;
  76
  77   if (flags & O_DIRECTORY)
  78     {
  79       /* The caller wants to require that the file we look up is a directory.
  80          We can do this without an extra RPC by appending a trailing slash
  81          to the file name we look up.  */
  82       size_t len = strlen (file_name);
  83       if (len == 0)
  84         file_name = "/";
  85       else if (file_name[len - 1] != '/')
  86         {
  87           char *n = alloca (len + 2);
  88           memcpy (n, file_name, len);
  89           n[len] = '/';
  90           n[len + 1] = '\0';
  91           file_name = n;
  92         }
  93     }
  94
  95   err = (*use_init_port) (startport, &lookup_op);
  96   if (! err)
  97     err = __hurd_file_name_lookup_retry (use_init_port, get_dtable_port,
  98                                          lookup, doretry, retryname,
  99                                          flags, mode, result);
 100
 101   return err;
 102 }
 103 weak_alias (__hurd_file_name_lookup, hurd_file_name_lookup)
 104
 105 error_t
 106 __hurd_file_name_split (error_t (*use_init_port)
 107                           (int which, error_t (*operate) (file_t)),
 108                         file_t (*get_dtable_port) (int fd),
 109                         error_t (*lookup)
 110                           (file_t dir, char *name, int flags, mode_t mode,
 111                            retry_type *do_retry, string_t retry_name,
 112                            mach_port_t *result),
 113                         const char *file_name,
 114                         file_t *dir, char **name)
 115 {
 116   error_t addref (file_t crdir)
 117     {
 118       *dir = crdir;
 119       return __mach_port_mod_refs (__mach_task_self (),
 120                                    crdir, MACH_PORT_RIGHT_SEND, +1);
 121     }
 122
 123   const char *lastslash = strrchr (file_name, '/');
 124
 125   if (lastslash != NULL)
 126     {
 127       if (lastslash == file_name)
 128         {
 129           /* "/foobar" => crdir + "foobar".  */
 130           *name = (char *) file_name + 1;
 131           return (*use_init_port) (INIT_PORT_CRDIR, &addref);
 132         }
 133       else
 134         {
 135           /* "/dir1/dir2/.../file".  */
 136           char dirname[lastslash - file_name + 1];
 137           memcpy (dirname, file_name, lastslash - file_name);
 138           dirname[lastslash - file_name] = '\0';
 139           *name = (char *) lastslash + 1;
 140           return
 141             __hurd_file_name_lookup (use_init_port, get_dtable_port, lookup,
 142                                      dirname, 0, 0, dir);
 143         }
 144     }
 145   else if (file_name[0] == '\0')
 146     return ENOENT;
 147   else
 148     {
 149       /* "foobar" => cwdir + "foobar".  */
 150       *name = (char *) file_name;
 151       return (*use_init_port) (INIT_PORT_CWDIR, &addref);
 152     }
 153 }
 154 weak_alias (__hurd_file_name_split, hurd_file_name_split)
 155
 156 /* This is the same as hurd_file_name_split, except that it ignores
 157    trailing slashes (so *NAME is never "").  */
 158 error_t
 159 __hurd_directory_name_split (error_t (*use_init_port)
 160                              (int which, error_t (*operate) (file_t)),
 161                              file_t (*get_dtable_port) (int fd),
 162                              error_t (*lookup)
 163                              (file_t dir, char *name, int flags, mode_t mode,
 164                               retry_type *do_retry, string_t retry_name,
 165                               mach_port_t *result),
 166                              const char *file_name,
 167                              file_t *dir, char **name)
 168 {
 169   error_t addref (file_t crdir)
 170     {
 171       *dir = crdir;
 172       return __mach_port_mod_refs (__mach_task_self (),
 173                                    crdir, MACH_PORT_RIGHT_SEND, +1);
 174     }
 175
 176   const char *lastslash = strrchr (file_name, '/');
 177
 178   if (lastslash != NULL && lastslash[1] == '\0')
 179     {
 180       /* Trailing slash doesn't count.  Look back further.  */
 181
 182       /* Back up over all trailing slashes.  */
 183       while (lastslash > file_name && *lastslash == '/')
 184         --lastslash;
 185
 186       /* Find the last one earlier in the string, before the trailing ones.  */
 187 #if __GLIBC__ > 2 || __GLIBC_MINOR__ >= 2
 188       lastslash = __memrchr (file_name, '/', lastslash - file_name);
 189 #else
 190       /* Keep backing up, looking for a slash.  */
 191       do
 192         if (lastslash == file_name)
 193           {
 194             /* Hit the start with no slash.  */
 195             lastslash = NULL;
 196             break;
 197           }
 198       while (*lastslash-- != '/');
 199 #endif
 200     }
 201
 202   if (lastslash != NULL)
 203     {
 204       if (lastslash == file_name)
 205         {
 206           /* "/foobar" => crdir + "foobar".  */
 207           *name = (char *) file_name + 1;
 208           return (*use_init_port) (INIT_PORT_CRDIR, &addref);
 209         }
 210       else
 211         {
 212           /* "/dir1/dir2/.../file".  */
 213           char dirname[lastslash - file_name + 1];
 214           memcpy (dirname, file_name, lastslash - file_name);
 215           dirname[lastslash - file_name] = '\0';
 216           *name = (char *) lastslash + 1;
 217           return
 218             __hurd_file_name_lookup (use_init_port, get_dtable_port, lookup,
 219                                      dirname, 0, 0, dir);
 220         }
 221     }
 222   else if (file_name[0] == '\0')
 223     return ENOENT;
 224   else
 225     {
 226       /* "foobar" => cwdir + "foobar".  */
 227       *name = (char *) file_name;
 228       return (*use_init_port) (INIT_PORT_CWDIR, &addref);
 229     }
 230 }
 231 weak_alias (__hurd_directory_name_split, hurd_directory_name_split)
 232
 233 \f
 234 file_t
 235 __file_name_lookup (const char *file_name, int flags, mode_t mode)
 236 {
 237   error_t err;
 238   file_t result;
 239
 240   err = __hurd_file_name_lookup (&_hurd_ports_use, &__getdport, 0,
 241                                  file_name, flags, mode & ~_hurd_umask,
 242                                  &result);
 243
 244   return err ? (__hurd_fail (err), MACH_PORT_NULL) : result;
 245 }
 246 weak_alias (__file_name_lookup, file_name_lookup)
 247
 248
 249 file_t
 250 __file_name_split (const char *file_name, char **name)
 251 {
 252   error_t err;
 253   file_t result;
 254
 255   err = __hurd_file_name_split (&_hurd_ports_use, &__getdport, 0,
 256                                 file_name, &result, name);
 257
 258   return err ? (__hurd_fail (err), MACH_PORT_NULL) : result;
 259 }
 260 weak_alias (__file_name_split, file_name_split)
 261
 262 file_t
 263 __directory_name_split (const char *directory_name, char **name)
 264 {
 265   error_t err;
 266   file_t result;
 267
 268   err = __hurd_directory_name_split (&_hurd_ports_use, &__getdport, 0,
 269                                      directory_name, &result, name);
 270
 271   return err ? (__hurd_fail (err), MACH_PORT_NULL) : result;
 272 }
 273 weak_alias (__directory_name_split, directory_name_split)
 274
 275
 276 file_t
 277 __file_name_lookup_under (file_t startdir,
 278                           const char *file_name, int flags, mode_t mode)
 279 {
 280   error_t err;
 281   file_t result;
 282
 283   error_t use_init_port (int which, error_t (*operate) (mach_port_t))
 284     {
 285       return (which == INIT_PORT_CWDIR ? (*operate) (startdir) :
 286               _hurd_ports_use (which, operate));
 287     }
 288
 289   err = __hurd_file_name_lookup (&use_init_port, &__getdport, 0,
 290                                  file_name, flags, mode & ~_hurd_umask,
 291                                  &result);
 292
 293   return err ? (__hurd_fail (err), MACH_PORT_NULL) : result;
 294 }
 295 weak_alias (__file_name_lookup_under, file_name_lookup_under)