File: getcwd.c

package info (click to toggle)
glibc 2.29-3
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, sid
  • size: 271,436 kB
  • sloc: ansic: 1,013,441; asm: 261,303; makefile: 11,428; sh: 10,300; python: 8,944; cpp: 5,062; awk: 1,956; perl: 514; yacc: 290; pascal: 182; sed: 73
file content (309 lines) | stat: -rw-r--r-- 8,834 bytes parent folder | download | duplicates (6)
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
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
/* Copyright (C) 1991-2019 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 Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#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 canonical absolute name of the given directory port, 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.
   If our root directory cannot be reached, the result will not begin with
   a slash to indicate that it is relative to some unknown root directory.  */

char *
__hurd_canonicalize_directory_name_internal (file_t thisdir,
					    char *buf,
					    size_t size)
{
  error_t err;
  mach_port_t rootid, thisid, rootdevid, thisdevid;
  ino64_t rootino, thisino;
  char *file_name;
  char *file_namep;
  file_t parent;
  char *dirbuf = NULL;
  unsigned int dirbufsize = 0;
  const size_t orig_size = size;

  inline void cleanup (void)
    {
      if (parent != thisdir)
	__mach_port_deallocate (__mach_task_self (), parent);

      __mach_port_deallocate (__mach_task_self (), thisid);
      __mach_port_deallocate (__mach_task_self (), thisdevid);
      __mach_port_deallocate (__mach_task_self (), rootid);

      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 get its identity.  */

  if (err = __USEPORT (CRDIR, __io_identity (port,
					     &rootid, &rootdevid, &rootino)))
    return __hurd_fail (err), NULL;
  __mach_port_deallocate (__mach_task_self (), rootdevid);

  /* Stat the port to the directory of interest.  */

  if (err = __io_identity (thisdir, &thisid, &thisdevid, &thisino))
    {
      __mach_port_deallocate (__mach_task_self (), rootid);
      return __hurd_fail (err), NULL;
    }

  parent = thisdir;
  while (thisid != rootid)
    {
      /* PARENT is a port to the directory we are currently on;
	 THISID, THISDEV, and THISINO are its identity.
	 Look in its parent (..) for a file with the same file number.  */

      struct dirent64 *d;
      mach_port_t dotid, dotdevid;
      ino64_t dotino;
      int mount_point;
      file_t newp;
      char *dirdata;
      size_t dirdatasize;
      int direntry, nentries;


      /* Look at the parent directory.  */
      newp = __file_name_lookup_under (parent, "..", O_READ, 0);
      if (newp == MACH_PORT_NULL)
	goto lose;
      if (parent != thisdir)
	__mach_port_deallocate (__mach_task_self (), parent);
      parent = newp;

      /* Get this directory's identity and figure out if it's a mount
         point.  */
      if (err = __io_identity (parent, &dotid, &dotdevid, &dotino))
	goto errlose;
      mount_point = dotdevid != thisdevid;

      if (thisid == dotid)
	{
	  /* `..' == `.' but it is not our root directory.  */
	  __mach_port_deallocate (__mach_task_self (), dotid);
	  __mach_port_deallocate (__mach_task_self (), dotdevid);
	  break;
	}

      /* 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 dirent64 *) &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 = __file_name_lookup_under (parent, d->d_name,
							 O_NOLINK, 0);
		  file_t id, devid;
		  ino64_t fileno;
		  if (try == MACH_PORT_NULL)
		    goto lose;
		  err = __io_identity (try, &id, &devid, &fileno);
		  __mach_port_deallocate (__mach_task_self (), try);
		  if (err)
		    goto inner_errlose;
		  __mach_port_deallocate (__mach_task_self (), id);
		  __mach_port_deallocate (__mach_task_self (), devid);
		  if (id == thisid)
		    goto found;
		}
	    }
	}

      if (err)
	{
	inner_errlose:		/* Goto ERRLOSE: after cleaning up.  */
	  __mach_port_deallocate (__mach_task_self (), dotid);
	  __mach_port_deallocate (__mach_task_self (), dotdevid);
	  goto errlose;
	}
      else if (nentries == 0)
	{
	  /* We got to the end of the directory without finding anything!
	     We are in a directory that has been unlinked, or something is
	     broken.  */
	  err = ENOENT;
	  goto inner_errlose;
	}
      else
      found:
	{
	  /* Prepend the directory name just discovered.  */

	  if (file_namep - file_name < d->d_namlen + 1)
	    {
	      if (orig_size > 0)
		{
		  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 + size / 2];
		  file_name = buf;
		  /* Move current contents up to the end of the buffer.
		     This is guaranteed to be non-overlapping.  */
		  memcpy (file_namep, file_namep - size / 2,
			  file_name + size - file_namep);
		}
	    }
	  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.  */
      __mach_port_deallocate (__mach_task_self (), thisid);
      __mach_port_deallocate (__mach_task_self (), thisdevid);
      thisid = dotid;
      thisdevid = dotdevid;
      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;

 errlose:
  /* Set errno.  */
  (void) __hurd_fail (err);
 lose:
  cleanup ();
  return NULL;
}
strong_alias (__hurd_canonicalize_directory_name_internal, _hurd_canonicalize_directory_name_internal)

char *
__canonicalize_directory_name_internal (const char *thisdir, char *buf,
					size_t size)
{
  char *result;
  file_t port = __file_name_lookup (thisdir, 0, 0);
  if (port == MACH_PORT_NULL)
    return NULL;
  result = __hurd_canonicalize_directory_name_internal (port, buf, size);
  __mach_port_deallocate (__mach_task_self (), port);
  return result;
}

/* 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)
{
  char *cwd =
    __USEPORT (CWDIR,
	       __hurd_canonicalize_directory_name_internal (port,
							    buf, size));
  return cwd;
}
weak_alias (__getcwd, getcwd)