summaryrefslogtreecommitdiff
path: root/libdiskfs/file-set-trans.c
blob: 07f365a5113adb60a56a48364906daaa76dae8a0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
/* libdiskfs implementation of fs.defs: file_set_translator
   Copyright (C) 1992, 1993, 1994, 1995, 1996 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2, or (at
   your option) any later version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */

#include "priv.h"
#include "fs_S.h"
#include <hurd/paths.h>
#include <hurd/fsys.h>

/* XXX - Temporary */
#define makedev(maj,min) ((((maj)&0xFF)<<8)+((min)&0xFF))

/* Implement file_set_translator as described in <hurd/fs.defs>. */
kern_return_t
diskfs_S_file_set_translator (struct protid *cred,
			      int passive_flags,
			      int active_flags,
			      int killtrans_flags,
			      char *passive,
			      u_int passivelen,
			      fsys_t active)
{
  struct node *np;
  error_t error;
  mach_port_t control = MACH_PORT_NULL;

  if (!cred)
    return EOPNOTSUPP;

  if (!(passive_flags & FS_TRANS_SET) && !(active_flags & FS_TRANS_SET))
    return 0;

  if ((passive_flags & FS_TRANS_SET) && diskfs_check_readonly ())
    return EROFS;

  if (passive && passive[passivelen - 1])
    return EINVAL;

  np = cred->po->np;

  mutex_lock (&np->lock);

  error = fshelp_isowner (&np->dn_stat, cred->user);
  if (error)
    {
      mutex_unlock (&np->lock);
      return error;
    }

  if (active_flags & FS_TRANS_SET)
    {
      error = fshelp_fetch_control (&np->transbox, &control);
      if (error)
	{
	  mutex_unlock (&np->lock);
	  return error;
	}

      if ((control != MACH_PORT_NULL) && ((active_flags & FS_TRANS_EXCL) == 0))
	{
	  mutex_unlock (&np->lock);
	  error = fsys_goaway (control, killtrans_flags);
	  mach_port_deallocate (mach_task_self (), control);
	  if (error && (error != MIG_SERVER_DIED)
	      && (error != MACH_SEND_INVALID_DEST))
	    return error;
	  error = 0;
	  mutex_lock (&np->lock);
	}
      else if (control != MACH_PORT_NULL)
	mach_port_deallocate (mach_task_self (), control);
    }

  /* Handle exclusive passive bit *first*.  */
  if ((passive_flags & FS_TRANS_SET)
      && (passive_flags & FS_TRANS_EXCL)
      && np->istranslated)
    {
      mutex_unlock (&np->lock);
      return EBUSY;
    }

  if (active_flags & FS_TRANS_SET)
    {
      error = fshelp_set_active (&np->transbox, active,
				 active_flags & FS_TRANS_EXCL);
      if (error)
	{
	  mutex_unlock (&np->lock);
	  return error;
	}
    }

  /* Set passive translator */
  if (passive_flags & FS_TRANS_SET)
    {
      if (!(passive_flags & FS_TRANS_FORCE))
	{
	  /* Handle the short-circuited translators */
	  mode_t newmode = 0;

	  if (diskfs_shortcut_symlink && !strcmp (passive, _HURD_SYMLINK))
	    newmode = S_IFLNK;
	  else if (diskfs_shortcut_chrdev && !(strcmp (passive, _HURD_CHRDEV)))
	    newmode = S_IFCHR;
	  else if (diskfs_shortcut_blkdev && !strcmp (passive, _HURD_BLKDEV))
	    newmode = S_IFBLK;
	  else if (diskfs_shortcut_fifo && !strcmp (passive, _HURD_FIFO))
	    newmode = S_IFIFO;
	  else if (diskfs_shortcut_ifsock && !strcmp (passive, _HURD_IFSOCK))
	    newmode = S_IFSOCK;

	  if (newmode)
	    {
	      if (S_ISDIR (np->dn_stat.st_mode))
		{
		  /* We can't allow this, because if the mode of the directory
		     changes, the links will be lost.  Perhaps it might be
		     allowed for empty directories, but that's too much of a
		     pain.  */
		  mutex_unlock (&np->lock);
		  return EISDIR;
		}
	      if (newmode == S_IFBLK || newmode == S_IFCHR)
		{
		  /* Find the device number from the arguments
		     of the translator. */
		  int major, minor;
		  char *arg;

		  arg = passive + strlen (passive) + 1;
		  assert (arg <= passive + passivelen);
		  if (arg == passive + passivelen)
		    {
		      mutex_unlock (&np->lock);
		      return EINVAL;
		    }
		  major = strtol (arg, 0, 0);

		  arg = arg + strlen (arg) + 1;
		  assert (arg < passive + passivelen);
		  if (arg == passive + passivelen)
		    {
		      mutex_unlock (&np->lock);
		      return EINVAL;
		    }
		  minor = strtol (arg, 0, 0);

		  error = diskfs_validate_rdev_change (np, 
						       makedev (major, minor));
		  if (error)
		    {
		      mutex_unlock (&np->lock);
		      return error;
		    }
		  np->dn_stat.st_rdev = makedev (major, minor);
		}

	      diskfs_truncate (np, 0);
	      if (newmode == S_IFLNK)
		{
		  char *arg = passive + strlen (passive) + 1;
		  assert (arg <= passive + passivelen);
		  if (arg == passive + passivelen)
		    {
		      mutex_unlock (&np->lock);
		      return EINVAL;
		    }

		  if (diskfs_create_symlink_hook)
		    error = (*diskfs_create_symlink_hook)(np, arg);
		  if (!diskfs_create_symlink_hook || error == EINVAL)
		    /* Store the argument in the file as the
		       target of the link */
		    error = diskfs_node_rdwr (np, arg, 0, strlen (arg),
					      1, cred, 0);
		  if (error)
		    {
		      mutex_unlock (&np->lock);
		      return error;
		    }
		}
	      newmode = (np->dn_stat.st_mode & ~S_IFMT) | newmode;
	      error = diskfs_validate_mode_change (np, newmode);
	      if (!error)
		{
		  np->dn_stat.st_mode = newmode;
		  diskfs_node_update (np, 1);
		}
	      mutex_unlock (&np->lock);
	      return error;
	    }
	}
      error = diskfs_set_translator (np, passive, passivelen, cred);
    }

  mutex_unlock (&np->lock);
  return error;
}