hurd/path-lookup.c

   1 /* Filename lookup using a search path
   2
   3    Copyright (C) 1995, 1996 Free Software Foundation, Inc.
   4
   5    Written by Miles Bader <miles@gnu.ai.mit.edu>
   6
   7    This program is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU General Public License as
   9    published by the Free Software Foundation; either version 2, or (at
  10    your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful, but
  13    WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
  20
  21 #include <string.h>
  22 #include <hurd.h>
  23 #include <hurd/lookup.h>
  24
  25 /* If FILE_NAME contains a '/', or PATH is NULL, call FUN with FILE_NAME, and
  26    return the result (if PREFIXED_NAME is non-NULL, setting *PREFIXED_NAME to
  27    NULL).  Otherwise, call FUN repeatedly with FILE_NAME prefixed with each
  28    successive `:' separated element of PATH, returning whenever FUN returns
  29    0 (if PREFIXED_NAME is non-NULL, setting *PREFIXED_NAME to the resulting
  30    prefixed path).  If FUN never returns 0, return the first non-ENOENT
  31    return value, or ENOENT if there is none.  */
  32 error_t
  33 file_name_path_scan (const char *file_name, const char *path,
  34                      error_t (*fun)(const char *name),
  35                      char **prefixed_name)
  36 {
  37   if (path == NULL || index (file_name, '/'))
  38     {
  39       if (prefixed_name)
  40         *prefixed_name = 0;
  41       return (*fun)(file_name);
  42     }
  43   else
  44     {
  45       error_t real_err = 0;
  46       size_t file_name_len = strlen (file_name);
  47
  48       for (;;)
  49         {
  50           error_t err;
  51           const char *next = index (path, ':') ?: path + strlen (path);
  52           size_t pfx_len = next - path;
  53           char pfxed_name[pfx_len + 2 + file_name_len + 1];
  54
  55           if (pfx_len == 0)
  56             pfxed_name[pfx_len++] = '.';
  57           else
  58             bcopy (path, pfxed_name, pfx_len);
  59           if (pfxed_name[pfx_len - 1] != '/')
  60             pfxed_name[pfx_len++] = '/';
  61           bcopy (file_name, pfxed_name + pfx_len, file_name_len + 1);
  62
  63           err = (*fun)(pfxed_name);
  64           if (err == 0)
  65             {
  66               if (prefixed_name)
  67                 *prefixed_name = strdup (pfxed_name);
  68               return 0;
  69             }
  70           if (!real_err && err != ENOENT)
  71             real_err = err;
  72
  73           if (*next == '\0')
  74             return real_err ?: ENOENT;
  75           else
  76             path = next + 1;
  77         }
  78     }
  79 }
  80
  81 /* Lookup FILE_NAME and return the node opened with FLAGS & MODE in result
  82    (see hurd_file_name_lookup for details), but a simple filename (without
  83    any directory prefixes) will be consectutively prefixed with the pathnames
  84    in the `:' separated list PATH until one succeeds in a successful lookup.
  85    If none succeed, then the first error that wasn't ENOENT is returned, or
  86    ENOENT if no other errors were returned.  If PREFIXED_NAME is non-NULL,
  87    then if RESULT is looked up directly, *PREFIXED_NAME is set to NULL, and
  88    if it is looked up using a prefix from PATH, *PREFIXED_NAME is set to
  89    malloced storage containing the prefixed name.  */
  90 error_t
  91 hurd_file_name_path_lookup (error_t (*use_init_port)
  92                             (int which,
  93                              error_t (*operate) (mach_port_t)),
  94                             file_t (*get_dtable_port) (int fd),
  95                             const char *file_name, const char *path,
  96                             int flags, mode_t mode,
  97                             file_t *result, char **prefixed_name)
  98 {
  99   error_t lookup (const char *name)
 100     {
 101       return
 102         __hurd_file_name_lookup (use_init_port, get_dtable_port,
 103                                  name, flags, mode, result);
 104     }
 105   return file_name_path_scan (file_name, path, lookup, prefixed_name);
 106 }
 107
 108 file_t
 109 file_name_path_lookup (const char *file_name, const char *path,
 110                        int flags, mode_t mode, char **prefixed_name)
 111 {
 112   error_t err;
 113   file_t result;
 114
 115   err = hurd_file_name_path_lookup (&_hurd_ports_use, &__getdport,
 116                                     file_name, path, flags, mode,
 117                                     &result, prefixed_name);
 118
 119   return err ? (__hurd_fail (err), MACH_PORT_NULL) : result;
 120 }