hurd/lookup-at.c

   1 /* Lookup helper function for Hurd implementation of *at functions.
   2    Copyright (C) 2006-2023 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    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <hurd.h>
  20 #include <hurd/lookup.h>
  21 #include <hurd/fd.h>
  22 #include <string.h>
  23 #include <fcntl.h>
  24
  25 file_t
  26 __file_name_lookup_at (int fd, int at_flags,
  27                        const char *file_name, int flags, mode_t mode)
  28 {
  29   error_t err;
  30   file_t result;
  31   int empty = at_flags & AT_EMPTY_PATH;
  32   int orig_flags;
  33
  34   at_flags &= ~AT_EMPTY_PATH;
  35
  36   err = __hurd_at_flags (&at_flags, &flags);
  37   if (err)
  38     return (__hurd_fail (err), MACH_PORT_NULL);
  39
  40   if (empty != 0 && file_name[0] == '\0')
  41     {
  42       enum retry_type doretry;
  43       char retryname[1024];     /* XXX string_t LOSES! */
  44
  45       err = HURD_DPORT_USE (fd, __dir_lookup (port, "", flags, mode,
  46                                               &doretry, retryname,
  47                                               &result));
  48
  49       if (! err)
  50         err = __hurd_file_name_lookup_retry (&_hurd_ports_use, &__getdport,
  51                                              NULL, doretry, retryname,
  52                                              flags, mode, &result);
  53
  54       return err ? (__hurd_dfail (fd, err), MACH_PORT_NULL) : result;
  55     }
  56
  57   orig_flags = flags;
  58   if (flags & O_TMPFILE)
  59     flags = O_DIRECTORY;
  60
  61   if (fd == AT_FDCWD || file_name[0] == '/')
  62     {
  63       err = __hurd_file_name_lookup (&_hurd_ports_use, &__getdport, 0,
  64                                      file_name, flags, mode & ~_hurd_umask,
  65                                      &result);
  66       if (err)
  67         {
  68           __hurd_fail (err);
  69           return MACH_PORT_NULL;
  70         }
  71     }
  72   else
  73     {
  74       file_t startdir;
  75       /* We need to look the file up relative to the given directory (and
  76          not our cwd).  For this to work, we supply our own wrapper for
  77          _hurd_ports_use, which replaces cwd with our startdir.  */
  78       error_t use_init_port (int which, error_t (*operate) (mach_port_t))
  79         {
  80           return (which == INIT_PORT_CWDIR ? (*operate) (startdir)
  81                   : _hurd_ports_use (which, operate));
  82         }
  83
  84       err = HURD_DPORT_USE (fd, (startdir = port,
  85                                  __hurd_file_name_lookup (&use_init_port,
  86                                                           &__getdport, NULL,
  87                                                           file_name,
  88                                                           flags,
  89                                                           mode & ~_hurd_umask,
  90                                                           &result)));
  91       if (err)
  92         {
  93           __hurd_dfail (fd, err);
  94           return MACH_PORT_NULL;
  95         }
  96     }
  97
  98   if (orig_flags & O_TMPFILE)
  99     {
 100       /* What we have looked up is not the file itself, but actually
 101          the directory to create the file in.  Do that now.  */
 102       file_t dir = result;
 103
 104       err = __dir_mkfile (dir, orig_flags & ~(O_TMPFILE | O_DIRECTORY),
 105                           mode, &result);
 106       __mach_port_deallocate (__mach_task_self (), dir);
 107       if (err)
 108         {
 109           __hurd_fail (err);
 110           return MACH_PORT_NULL;
 111         }
 112     }
 113
 114   return result;
 115 }
 116
 117 file_t
 118 __file_name_split_at (int fd, const char *file_name, char **name)
 119 {
 120   error_t err;
 121   file_t result;
 122
 123   if (fd == AT_FDCWD || file_name[0] == '/')
 124     return __file_name_split (file_name, name);
 125
 126   err = __hurd_file_name_split (&_hurd_ports_use, &__getdport, 0,
 127                                 file_name, &result, name);
 128
 129   file_t startdir;
 130   error_t use_init_port (int which, error_t (*operate) (mach_port_t))
 131   {
 132     return (which == INIT_PORT_CWDIR ? (*operate) (startdir)
 133             : _hurd_ports_use (which, operate));
 134   }
 135
 136   err = HURD_DPORT_USE (fd, (startdir = port,
 137                              __hurd_file_name_split (&use_init_port,
 138                                                      &__getdport, 0,
 139                                                      file_name,
 140                                                      &result, name)));
 141
 142   return err ? (__hurd_dfail (fd, err), MACH_PORT_NULL) : result;
 143 }
 144
 145 file_t
 146 __directory_name_split_at (int fd, const char *directory_name, char **name)
 147 {
 148   error_t err;
 149   file_t result;
 150
 151   if (fd == AT_FDCWD || directory_name[0] == '/')
 152     return __directory_name_split (directory_name, name);
 153
 154   file_t startdir;
 155   error_t use_init_port (int which, error_t (*operate) (mach_port_t))
 156     {
 157       return (which == INIT_PORT_CWDIR ? (*operate) (startdir)
 158               : _hurd_ports_use (which, operate));
 159     }
 160
 161   err = HURD_DPORT_USE (fd, (startdir = port,
 162                              __hurd_directory_name_split (&use_init_port,
 163                                                           &__getdport, 0,
 164                                                           directory_name,
 165                                                           &result, name)));
 166
 167   return err ? (__hurd_dfail (fd, err), MACH_PORT_NULL) : result;
 168 }