aboutsummaryrefslogtreecommitdiff
path: root/sysdeps/mach/hurd/getcwd.c
blob: c0d9bcd5678141185f3d28b00c43ad10ab6b8b3f (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
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
/* Copyright (C) 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
This file is part of the GNU C Library.

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

The GNU C Library 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
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA.  */

#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <hurd.h>
#include <hurd/port.h>
#include <dirent.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <fcntl.h>


/* Get the pathname of the current working directory, and put it in SIZE
   bytes of BUF.  Returns NULL if the directory couldn't be determined or
   SIZE was too small.  If successful, returns BUF.  In GNU, if BUF is
   NULL, an array is allocated with `malloc'; the array is SIZE bytes long,
   unless SIZE <= 0, in which case it is as big as necessary.  */

char *
getcwd (char *buf, size_t size)
{
  error_t err;
  dev_t rootdev, thisdev;
  ino_t rootino, thisino;
  char *file_name;
  register char *file_namep;
  struct stat st;
  file_t parent;
  char *dirbuf = NULL;
  unsigned int dirbufsize = 0;
  file_t crdir;
  struct hurd_userlink crdir_ulink;

  inline void cleanup (void)
    {
      _hurd_port_free (&_hurd_ports[INIT_PORT_CRDIR], &crdir_ulink, crdir);
      __mach_port_deallocate (__mach_task_self (), parent);

      if (dirbuf != NULL)
	__vm_deallocate (__mach_task_self (),
			 (vm_address_t) dirbuf, dirbufsize);
    }

      
  if (size == 0)
    {
      if (buf != NULL)
	{
	  errno = EINVAL;
	  return NULL;
	}

      size = FILENAME_MAX * 4 + 1;	/* Good starting guess.  */
    }

  if (buf != NULL)
    file_name = buf;
  else
    {
      file_name = malloc (size);
      if (file_name == NULL)
	return NULL;
    }

  file_namep = file_name + size;
  *--file_namep = '\0';

  /* Get a port to our root directory and stat it.  */

  crdir = _hurd_port_get (&_hurd_ports[INIT_PORT_CRDIR], &crdir_ulink);
  if (err = __io_stat (crdir, &st))
    {
      _hurd_port_free (&_hurd_ports[INIT_PORT_CRDIR], &crdir_ulink, crdir);
      return __hurd_fail (err), NULL;
    }
  rootdev = st.st_dev;
  rootino = st.st_ino;

  /* Get a port to our current working directory and stat it.  */

  if (err = __USEPORT (CWDIR, __mach_port_mod_refs (__mach_task_self (),
						    (parent = port),
						    MACH_PORT_RIGHT_SEND,
						    1)))
    {
      _hurd_port_free (&_hurd_ports[INIT_PORT_CRDIR], &crdir_ulink, crdir);
      return __hurd_fail (err), NULL;
    }
  if (err = __io_stat (parent, &st))
    {
      cleanup ();
      return __hurd_fail (err), NULL;
    }

  thisdev = st.st_dev;
  thisino = st.st_ino;

  while (!(thisdev == rootdev && thisino == rootino))
    {
      /* PARENT is a port to the directory we are currently on;
	 THISDEV and THISINO are its device and node numbers.
	 Look in its parent (..) for a file with the same numbers.  */

      struct dirent *d;
      dev_t dotdev;
      ino_t dotino;
      int mount_point;
      file_t newp;
      char *dirdata;
      unsigned int dirdatasize;
      int direntry, nentries;

      /* Look at the parent directory.  */
      if (err = __hurd_file_name_lookup (crdir, parent, "..", O_READ, 0, &newp))
	goto lose;
      __mach_port_deallocate (__mach_task_self (), parent);
      parent = newp;

      /* Figure out if this directory is a mount point.  */
      if (err = __io_stat (parent, &st))
	goto lose;
      dotdev = st.st_dev;
      dotino = st.st_ino;
      mount_point = dotdev != thisdev;

      /* Search for the last directory.  */
      direntry = 0;
      dirdata = dirbuf;
      dirdatasize = dirbufsize;
      while (!(err = __dir_readdir (parent, &dirdata, &dirdatasize,
				    direntry, -1, 0, &nentries)) &&
	     nentries != 0)	     
	{
	  /* We have a block of directory entries.  */

	  unsigned int offset;

	  direntry += nentries;

	  if (dirdata != dirbuf)
	    {
	      /* The data was passed out of line, so our old buffer is no
		 longer useful.  Deallocate the old buffer and reset our
		 information for the new buffer.  */
	      __vm_deallocate (__mach_task_self (),
			       (vm_address_t) dirbuf, dirbufsize);
	      dirbuf = dirdata;
	      dirbufsize = round_page (dirdatasize);
	    }

	  /* Iterate over the returned directory entries, looking for one
	     whose file number is THISINO.  */

	  offset = 0;
	  while (offset < dirdatasize)
	    {
	      d = (struct dirent *) &dirdata[offset];
	      offset += d->d_reclen;

	      /* Ignore `.' and `..'.  */	
	      if (d->d_name[0] == '.' &&
		  (d->d_namlen == 1 ||
		   (d->d_namlen == 2 && d->d_name[1] == '.')))
		continue;

	      if (mount_point || d->d_ino == thisino)
		{
		  file_t try;
		  if (err = __hurd_file_name_lookup (crdir, parent, d->d_name,
						     O_NOLINK, 0, &try))
		    goto lose;
		  err = __io_stat (try, &st);
		  __mach_port_deallocate (__mach_task_self (), try);
		  if (err)
		    goto lose;
		  if (st.st_dev == thisdev && st.st_ino == thisino)
		    break;
		}
	    }
	}

      if (err)
	goto lose;
      else
	{
	  /* Prepend the directory name just discovered.  */

	  if (file_namep - file_name < d->d_namlen + 1)
	    {
	      if (buf != NULL)
		{
		  errno = ERANGE;
		  return NULL;
		}
	      else
		{
		  size *= 2;
		  buf = realloc (file_name, size);
		  if (buf == NULL)
		    {
		      free (file_name);
		      return NULL;
		    }
		  file_namep = &buf[file_namep - file_name];
		  file_name = buf;
		}
	    }
	  file_namep -= d->d_namlen;
	  (void) memcpy (file_namep, d->d_name, d->d_namlen);
	  *--file_namep = '/';
	}

      /* The next iteration will find the name of the directory we
	 just searched through.  */
      thisdev = dotdev;
      thisino = dotino;
    }

  if (file_namep == &file_name[size - 1])
    /* We found nothing and got all the way to the root.
       So the root is our current directory.  */
    *--file_namep = '/';

  memmove (file_name, file_namep, file_name + size - file_namep);
  cleanup ();
  return file_name;

 lose:
  cleanup ();
  return NULL;
}