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[/] [or1k/] [trunk/] [newlib-1.10.0/] [newlib/] [libc/] [unix/] [getcwd.c] - Blame information for rev 1773

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Line No. Rev Author Line
1 1010 ivang
/*
2
 * Copyright (c) 1989, 1991 The Regents of the University of California.
3
 * All rights reserved.
4
 *
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 * Redistribution and use in source and binary forms, with or without
6
 * modification, are permitted provided that the following conditions
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 * are met:
8
 * 1. Redistributions of source code must retain the above copyright
9
 *    notice, this list of conditions and the following disclaimer.
10
 * 2. Redistributions in binary form must reproduce the above copyright
11
 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. All advertising materials mentioning features or use of this software
14
 *    must display the following acknowledgement:
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 *      This product includes software developed by the University of
16
 *      California, Berkeley and its contributors.
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 * 4. Neither the name of the University nor the names of its contributors
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 *    may be used to endorse or promote products derived from this software
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 *    without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * SUCH DAMAGE.
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 */
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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)getcwd.c    5.11 (Berkeley) 2/24/91";
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#endif /* LIBC_SCCS and not lint */
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#include <sys/stat.h>
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#include <errno.h>
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#include <dirent.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <reent.h>
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#include <_syslist.h>
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#define bcopy(a,b,c)    memmove (b,a,c)
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50
#define ISDOT(dp) \
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        (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \
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           (dp->d_name[1] == '.' && dp->d_name[2] == '\0')))
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54
#ifndef _REENT_ONLY
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56
char *
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getcwd (pt, size)
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     char *pt;
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     size_t size;
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{
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  register struct dirent *dp;
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  register DIR *dir;
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  register dev_t dev;
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  register ino_t ino;
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  register int first;
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  register char *bpt, *bup;
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  struct stat s;
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  dev_t root_dev;
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  ino_t root_ino;
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  size_t ptsize, upsize;
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  int save_errno;
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  char *ept, *eup, *up;
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  /*
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   * If no buffer specified by the user, allocate one as necessary.
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   * If a buffer is specified, the size has to be non-zero.  The path
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   * is built from the end of the buffer backwards.
78
   */
79
 
80
  if (pt)
81
    {
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      ptsize = 0;
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      if (!size)
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        {
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          errno = EINVAL;
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          return (char *) NULL;
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        }
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      ept = pt + size;
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    }
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  else
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    {
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      if (!(pt = (char *) malloc (ptsize = 1024 - 4)))
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        {
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          return (char *) NULL;
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        }
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      ept = pt + ptsize;
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    }
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  bpt = ept - 1;
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  *bpt = '\0';
100
 
101
  /*
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   * Allocate bytes (1024 - malloc space) for the string of "../"'s.
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   * Should always be enough (it's 340 levels).  If it's not, allocate
104
   * as necessary.  Special * case the first stat, it's ".", not "..".
105
   */
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107
  if (!(up = (char *) malloc (upsize = 1024 - 4)))
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    {
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      goto err;
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    }
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  eup = up + MAXPATHLEN;
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  bup = up;
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  up[0] = '.';
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  up[1] = '\0';
115
 
116
  /* Save root values, so know when to stop. */
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  if (stat ("/", &s))
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    goto err;
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  root_dev = s.st_dev;
120
  root_ino = s.st_ino;
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122
  errno = 0;                     /* XXX readdir has no error return. */
123
 
124
  for (first = 1;; first = 0)
125
    {
126
      /* Stat the current level. */
127
      if (_stat (up, &s))
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        goto err;
129
 
130
      /* Save current node values. */
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      ino = s.st_ino;
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      dev = s.st_dev;
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      /* Check for reaching root. */
135
      if (root_dev == dev && root_ino == ino)
136
        {
137
          *--bpt = '/';
138
          /*
139
           * It's unclear that it's a requirement to copy the
140
           * path to the beginning of the buffer, but it's always
141
           * been that way and stuff would probably break.
142
           */
143
          (void) bcopy (bpt, pt, ept - bpt);
144
          free (up);
145
          return pt;
146
        }
147
 
148
      /*
149
       * Build pointer to the parent directory, allocating memory
150
       * as necessary.  Max length is 3 for "../", the largest
151
       * possible component name, plus a trailing NULL.
152
       */
153
 
154
      if (bup + 3 + MAXNAMLEN + 1 >= eup)
155
        {
156
          if (!(up = (char *) realloc (up, upsize *= 2)))
157
            {
158
              goto err;
159
            }
160
          bup = up;
161
          eup = up + upsize;
162
        }
163
      *bup++ = '.';
164
      *bup++ = '.';
165
      *bup = '\0';
166
 
167
      /* Open and stat parent directory. */
168
      if (!(dir = _opendir (up)) || _fstat (__dirfd (dir), &s))
169
        goto err;
170
 
171
      /* Add trailing slash for next directory. */
172
      *bup++ = '/';
173
 
174
      /*
175
       * If it's a mount point, have to stat each element because
176
       * the inode number in the directory is for the entry in the
177
       * parent directory, not the inode number of the mounted file.
178
       */
179
 
180
      save_errno = 0;
181
      if (s.st_dev == dev)
182
        {
183
          for (;;)
184
            {
185
              if (!(dp = _readdir (dir)))
186
                goto notfound;
187
              if (dp->d_ino == ino)
188
                break;
189
            }
190
        }
191
      else
192
        for (;;)
193
          {
194
            if (!(dp = _readdir (dir)))
195
              goto notfound;
196
            if (ISDOT (dp))
197
              continue;
198
            bcopy (dp->d_name, bup, strlen (dp->d_name) + 1);
199
 
200
            /* Save the first error for later. */
201
            if (stat (up, &s))
202
              {
203
                if (!save_errno)
204
                  save_errno = errno;
205
                errno = 0;
206
                continue;
207
              }
208
            if (s.st_dev == dev && s.st_ino == ino)
209
              break;
210
          }
211
 
212
      /*
213
       * Check for length of the current name, preceding slash,
214
       * leading slash.
215
       */
216
 
217
      if (bpt - pt <= strlen (dp->d_name) + (first ? 1 : 2))
218
        {
219
          size_t len, off;
220
 
221
          if (!ptsize)
222
            {
223
              errno = ERANGE;
224
              goto err;
225
            }
226
          off = bpt - pt;
227
          len = ept - bpt;
228
          if (!(pt = (char *) realloc (pt, ptsize *= 2)))
229
            {
230
              goto err;
231
            }
232
          bpt = pt + off;
233
          ept = pt + ptsize;
234
          (void) bcopy (bpt, ept - len, len);
235
          bpt = ept - len;
236
        }
237
      if (!first)
238
        *--bpt = '/';
239
      bpt -= strlen (dp->d_name);
240
      bcopy (dp->d_name, bpt, strlen (dp->d_name));
241
      (void) _closedir (dir);
242
 
243
      /* Truncate any file name. */
244
      *bup = '\0';
245
    }
246
 
247
notfound:
248
  /*
249
   * If readdir set errno, use it, not any saved error; otherwise,
250
   * didn't find the current directory in its parent directory, set
251
   * errno to ENOENT.
252
   */
253
 
254
  if (!errno)
255
    errno = save_errno ? save_errno : ENOENT;
256
  /* FALLTHROUGH */
257
 
258
err:
259
  if (ptsize)
260
    free (pt);
261
  free (up);
262
  return (char *) NULL;
263
}
264
 
265
#endif /* _REENT_ONLY */

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