aboutsummaryrefslogtreecommitdiff
path: root/gnulib/import/canonicalize-lgpl.c
blob: 7d3c710f10f0d98713068d30dba4227d0da83c72 (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
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
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
/* Return the canonical absolute name of a given file.
   Copyright (C) 1996-2020 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   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 3 of the License, 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, see <https://www.gnu.org/licenses/>.  */

#ifndef _LIBC
/* Don't use __attribute__ __nonnull__ in this compilation unit.  Otherwise gcc
   optimizes away the name == NULL test below.  */
# define _GL_ARG_NONNULL(params)

# define _GL_USE_STDLIB_ALLOC 1
# include <config.h>
#endif

#if !HAVE_CANONICALIZE_FILE_NAME || !FUNC_REALPATH_WORKS || defined _LIBC

/* Specification.  */
#include <stdlib.h>

#include <alloca.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>
#if HAVE_SYS_PARAM_H || defined _LIBC
# include <sys/param.h>
#endif
#include <sys/stat.h>
#include <errno.h>
#include <stddef.h>

#ifdef _LIBC
# include <shlib-compat.h>
#else
# define SHLIB_COMPAT(lib, introduced, obsoleted) 0
# define versioned_symbol(lib, local, symbol, version) extern int dummy
# define compat_symbol(lib, local, symbol, version)
# define weak_alias(local, symbol)
# define __canonicalize_file_name canonicalize_file_name
# define __realpath realpath
# include "pathmax.h"
# include "malloca.h"
# include "dosname.h"
# if HAVE_GETCWD
#  if IN_RELOCWRAPPER
    /* When building the relocatable program wrapper, use the system's getcwd
       function, not the gnulib override, otherwise we would get a link error.
     */
#   undef getcwd
#  endif
#  if defined VMS && !defined getcwd
    /* We want the directory in Unix syntax, not in VMS syntax.
       The gnulib override of 'getcwd' takes 2 arguments; the original VMS
       'getcwd' takes 3 arguments.  */
#   define __getcwd(buf, max) getcwd (buf, max, 0)
#  else
#   define __getcwd getcwd
#  endif
# else
#  define __getcwd(buf, max) getwd (buf)
# endif
# define __readlink readlink
# define __set_errno(e) errno = (e)
# ifndef MAXSYMLINKS
#  ifdef SYMLOOP_MAX
#   define MAXSYMLINKS SYMLOOP_MAX
#  else
#   define MAXSYMLINKS 20
#  endif
# endif
#endif

#ifndef DOUBLE_SLASH_IS_DISTINCT_ROOT
# define DOUBLE_SLASH_IS_DISTINCT_ROOT 0
#endif

/* Define this independently so that stdint.h is not a prerequisite.  */
#ifndef SIZE_MAX
# define SIZE_MAX ((size_t) -1)
#endif

#if !FUNC_REALPATH_WORKS || defined _LIBC

static void
alloc_failed (void)
{
#if defined _WIN32 && ! defined __CYGWIN__
  /* Avoid errno problem without using the malloc or realloc modules; see:
     https://lists.gnu.org/r/bug-gnulib/2016-08/msg00025.html  */
  errno = ENOMEM;
#endif
}

/* Return the canonical absolute name of file NAME.  A canonical name
   does not contain any ".", ".." components nor any repeated path
   separators ('/') or symlinks.  All path components must exist.  If
   RESOLVED is null, the result is malloc'd; otherwise, if the
   canonical name is PATH_MAX chars or more, returns null with 'errno'
   set to ENAMETOOLONG; if the name fits in fewer than PATH_MAX chars,
   returns the name in RESOLVED.  If the name cannot be resolved and
   RESOLVED is non-NULL, it contains the path of the first component
   that cannot be resolved.  If the path can be resolved, RESOLVED
   holds the same value as the value returned.  */

char *
__realpath (const char *name, char *resolved)
{
  char *rpath, *dest, *extra_buf = NULL;
  const char *start, *end, *rpath_limit;
  long int path_max;
  int num_links = 0;
  size_t prefix_len;

  if (name == NULL)
    {
      /* As per Single Unix Specification V2 we must return an error if
         either parameter is a null pointer.  We extend this to allow
         the RESOLVED parameter to be NULL in case the we are expected to
         allocate the room for the return value.  */
      __set_errno (EINVAL);
      return NULL;
    }

  if (name[0] == '\0')
    {
      /* As per Single Unix Specification V2 we must return an error if
         the name argument points to an empty string.  */
      __set_errno (ENOENT);
      return NULL;
    }

#ifdef PATH_MAX
  path_max = PATH_MAX;
#else
  path_max = pathconf (name, _PC_PATH_MAX);
  if (path_max <= 0)
    path_max = 8192;
#endif

  if (resolved == NULL)
    {
      rpath = malloc (path_max);
      if (rpath == NULL)
        {
          alloc_failed ();
          return NULL;
        }
    }
  else
    rpath = resolved;
  rpath_limit = rpath + path_max;

  /* This is always zero for Posix hosts, but can be 2 for MS-Windows
     and MS-DOS X:/foo/bar file names.  */
  prefix_len = FILE_SYSTEM_PREFIX_LEN (name);

  if (!IS_ABSOLUTE_FILE_NAME (name))
    {
      if (!__getcwd (rpath, path_max))
        {
          rpath[0] = '\0';
          goto error;
        }
      dest = strchr (rpath, '\0');
      start = name;
      prefix_len = FILE_SYSTEM_PREFIX_LEN (rpath);
    }
  else
    {
      dest = rpath;
      if (prefix_len)
        {
          memcpy (rpath, name, prefix_len);
          dest += prefix_len;
        }
      *dest++ = '/';
      if (DOUBLE_SLASH_IS_DISTINCT_ROOT)
        {
          if (ISSLASH (name[1]) && !ISSLASH (name[2]) && !prefix_len)
            *dest++ = '/';
          *dest = '\0';
        }
      start = name + prefix_len;
    }

  for (end = start; *start; start = end)
    {
#ifdef _LIBC
      struct stat64 st;
#else
      struct stat st;
#endif

      /* Skip sequence of multiple path-separators.  */
      while (ISSLASH (*start))
        ++start;

      /* Find end of path component.  */
      for (end = start; *end && !ISSLASH (*end); ++end)
        /* Nothing.  */;

      if (end - start == 0)
        break;
      else if (end - start == 1 && start[0] == '.')
        /* nothing */;
      else if (end - start == 2 && start[0] == '.' && start[1] == '.')
        {
          /* Back up to previous component, ignore if at root already.  */
          if (dest > rpath + prefix_len + 1)
            for (--dest; dest > rpath && !ISSLASH (dest[-1]); --dest)
              continue;
          if (DOUBLE_SLASH_IS_DISTINCT_ROOT
              && dest == rpath + 1 && !prefix_len
              && ISSLASH (*dest) && !ISSLASH (dest[1]))
            dest++;
        }
      else
        {
          size_t new_size;

          if (!ISSLASH (dest[-1]))
            *dest++ = '/';

          if (dest + (end - start) >= rpath_limit)
            {
              ptrdiff_t dest_offset = dest - rpath;
              char *new_rpath;

              if (resolved)
                {
                  __set_errno (ENAMETOOLONG);
                  if (dest > rpath + prefix_len + 1)
                    dest--;
                  *dest = '\0';
                  goto error;
                }
              new_size = rpath_limit - rpath;
              if (end - start + 1 > path_max)
                new_size += end - start + 1;
              else
                new_size += path_max;
              new_rpath = (char *) realloc (rpath, new_size);
              if (new_rpath == NULL)
                {
                  alloc_failed ();
                  goto error;
                }
              rpath = new_rpath;
              rpath_limit = rpath + new_size;

              dest = rpath + dest_offset;
            }

#ifdef _LIBC
          dest = __mempcpy (dest, start, end - start);
#else
          memcpy (dest, start, end - start);
          dest += end - start;
#endif
          *dest = '\0';

          /* FIXME: if lstat fails with errno == EOVERFLOW,
             the entry exists.  */
#ifdef _LIBC
          if (__lxstat64 (_STAT_VER, rpath, &st) < 0)
#else
          if (lstat (rpath, &st) < 0)
#endif
            goto error;

          if (S_ISLNK (st.st_mode))
            {
              char *buf;
              size_t len;
              ssize_t n;

              if (++num_links > MAXSYMLINKS)
                {
                  __set_errno (ELOOP);
                  goto error;
                }

              buf = malloca (path_max);
              if (!buf)
                {
                  __set_errno (ENOMEM);
                  goto error;
                }

              n = __readlink (rpath, buf, path_max - 1);
              if (n < 0)
                {
                  int saved_errno = errno;
                  freea (buf);
                  __set_errno (saved_errno);
                  goto error;
                }
              buf[n] = '\0';

              if (!extra_buf)
                {
                  extra_buf = malloca (path_max);
                  if (!extra_buf)
                    {
                      freea (buf);
                      __set_errno (ENOMEM);
                      goto error;
                    }
                }

              len = strlen (end);
              /* Check that n + len + 1 doesn't overflow and is <= path_max. */
              if (n >= SIZE_MAX - len || n + len >= path_max)
                {
                  freea (buf);
                  __set_errno (ENAMETOOLONG);
                  goto error;
                }

              /* Careful here, end may be a pointer into extra_buf... */
              memmove (&extra_buf[n], end, len + 1);
              name = end = memcpy (extra_buf, buf, n);

              if (IS_ABSOLUTE_FILE_NAME (buf))
                {
                  size_t pfxlen = FILE_SYSTEM_PREFIX_LEN (buf);

                  if (pfxlen)
                    memcpy (rpath, buf, pfxlen);
                  dest = rpath + pfxlen;
                  *dest++ = '/'; /* It's an absolute symlink */
                  if (DOUBLE_SLASH_IS_DISTINCT_ROOT)
                    {
                      if (ISSLASH (buf[1]) && !ISSLASH (buf[2]) && !pfxlen)
                        *dest++ = '/';
                      *dest = '\0';
                    }
                  /* Install the new prefix to be in effect hereafter.  */
                  prefix_len = pfxlen;
                }
              else
                {
                  /* Back up to previous component, ignore if at root
                     already: */
                  if (dest > rpath + prefix_len + 1)
                    for (--dest; dest > rpath && !ISSLASH (dest[-1]); --dest)
                      continue;
                  if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rpath + 1
                      && ISSLASH (*dest) && !ISSLASH (dest[1]) && !prefix_len)
                    dest++;
                }
            }
          else if (!S_ISDIR (st.st_mode) && *end != '\0')
            {
              __set_errno (ENOTDIR);
              goto error;
            }
        }
    }
  if (dest > rpath + prefix_len + 1 && ISSLASH (dest[-1]))
    --dest;
  if (DOUBLE_SLASH_IS_DISTINCT_ROOT && dest == rpath + 1 && !prefix_len
      && ISSLASH (*dest) && !ISSLASH (dest[1]))
    dest++;
  *dest = '\0';

  if (extra_buf)
    freea (extra_buf);

  return rpath;

error:
  {
    int saved_errno = errno;
    if (extra_buf)
      freea (extra_buf);
    if (resolved == NULL)
      free (rpath);
    __set_errno (saved_errno);
  }
  return NULL;
}
versioned_symbol (libc, __realpath, realpath, GLIBC_2_3);
#endif /* !FUNC_REALPATH_WORKS || defined _LIBC */


#if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_3)
char *
attribute_compat_text_section
__old_realpath (const char *name, char *resolved)
{
  if (resolved == NULL)
    {
      __set_errno (EINVAL);
      return NULL;
    }

  return __realpath (name, resolved);
}
compat_symbol (libc, __old_realpath, realpath, GLIBC_2_0);
#endif


char *
__canonicalize_file_name (const char *name)
{
  return __realpath (name, NULL);
}
weak_alias (__canonicalize_file_name, canonicalize_file_name)

#else

/* This declaration is solely to ensure that after preprocessing
   this file is never empty.  */
typedef int dummy;

#endif