/[path-sandbox]/tags/sandbox_1_2_13/canonicalize.c
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Contents of /tags/sandbox_1_2_13/canonicalize.c

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Revision 43 - (hide annotations) (download) (as text)
Sat Apr 23 20:44:15 2005 UTC (9 years, 2 months ago) by azarah
Original Path: trunk/canonicalize.c
File MIME type: text/x-csrc
File size: 4787 byte(s)
Make sure all functions used in libsandbox.c is declared static.  Define
SB_STATIC in localdecls.h for this.  Include sandbox_futils.c rather than
linking with its object.  Hopefully this will fix bug #90153.

1 ferringb 2 /* Return the canonical absolute name of a given file.
2     Copyright (C) 1996-2001, 2002 Free Software Foundation, Inc.
3     This file is part of the GNU C Library.
4    
5     The GNU C Library is free software; you can redistribute it and/or
6     modify it under the terms of the GNU Lesser General Public
7     License as published by the Free Software Foundation; either
8     version 2.1 of the License, or (at your option) any later version.
9    
10     The GNU C Library is distributed in the hope that it will be useful,
11     but WITHOUT ANY WARRANTY; without even the implied warranty of
12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13     Lesser General Public License for more details.
14    
15     You should have received a copy of the GNU Lesser General Public
16     License along with the GNU C Library; if not, write to the Free
17     Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
18     02111-1307 USA. */
19    
20     /*
21     * $Header$
22     */
23    
24     #include <stdlib.h>
25     #include <string.h>
26     #include <unistd.h>
27     #include <limits.h>
28     #include <sys/param.h>
29     #include <sys/stat.h>
30     #include <errno.h>
31     #include <stddef.h>
32    
33 ferringb 25 #include "config.h"
34 ferringb 26 #include "localdecls.h"
35 ferringb 25
36 ferringb 2 #ifndef __set_errno
37     # define __set_errno(val) errno = (val)
38     #endif
39    
40     /* Return the canonical absolute name of file NAME. A canonical name
41     does not contain any `.', `..' components nor any repeated path
42     separators ('/') or symlinks. All path components must exist. If
43     RESOLVED is null, the result is malloc'd; otherwise, if the
44     canonical name is SB_PATH_MAX chars or more, returns null with `errno'
45     set to ENAMETOOLONG; if the name fits in fewer than SB_PATH_MAX chars,
46     returns the name in RESOLVED. If the name cannot be resolved and
47     RESOLVED is non-NULL, it contains the path of the first component
48     that cannot be resolved. If the path can be resolved, RESOLVED
49 azarah 30 holds the same value as the value returned. */
50 ferringb 2
51     /* Modified: 19 Aug 2002; Martin Schlemmer <azarah@gentoo.org>
52     *
53     * Cleaned up unneeded stuff, and change so that it will not
54     * resolve symlinks. Also prepended a 'e' to functions that
55     * I did not rip out.
56     *
57     */
58    
59 azarah 43 SB_STATIC char *
60 ferringb 2 erealpath(const char *name, char *resolved)
61     {
62     char *rpath, *dest;
63     const char *start, *end, *rpath_limit;
64     long int path_max;
65    
66     if (name == NULL) {
67     /* As per Single Unix Specification V2 we must return an error if
68 azarah 30 either parameter is a null pointer. We extend this to allow
69 ferringb 2 the RESOLVED parameter to be NULL in case the we are expected to
70     allocate the room for the return value. */
71     __set_errno(EINVAL);
72     return NULL;
73     }
74    
75     if (name[0] == '\0') {
76     /* As per Single Unix Specification V2 we must return an error if
77     the name argument points to an empty string. */
78     __set_errno(ENOENT);
79     return NULL;
80     }
81     #ifdef SB_PATH_MAX
82     path_max = SB_PATH_MAX;
83     #else
84     path_max = pathconf(name, _PC_PATH_MAX);
85     if (path_max <= 0)
86     path_max = 1024;
87     #endif
88    
89     if (resolved == NULL) {
90     rpath = malloc(path_max);
91     if (rpath == NULL)
92     return NULL;
93     } else
94     rpath = resolved;
95     rpath_limit = rpath + path_max;
96    
97     if (name[0] != '/') {
98     if (!egetcwd(rpath, path_max)) {
99     rpath[0] = '\0';
100     goto error;
101     }
102     dest = strchr(rpath, '\0');
103     } else {
104     rpath[0] = '/';
105     dest = rpath + 1;
106     }
107    
108     for (start = end = name; *start; start = end) {
109     /* Skip sequence of multiple path-separators. */
110     while (*start == '/')
111     ++start;
112    
113 azarah 30 /* Find end of path component. */
114 ferringb 2 for (end = start; *end && *end != '/'; ++end)
115     /* Nothing. */ ;
116    
117     if (end - start == 0)
118     break;
119     else if (end - start == 1 && start[0] == '.')
120     /* nothing */ ;
121     else if (end - start == 2 && start[0] == '.' && start[1] == '.') {
122     /* Back up to previous component, ignore if at root already. */
123     if (dest > rpath + 1)
124     while ((--dest)[-1] != '/') ;
125     } else {
126     size_t new_size;
127    
128     if (dest[-1] != '/')
129     *dest++ = '/';
130    
131     if (dest + (end - start) >= rpath_limit) {
132     ptrdiff_t dest_offset = dest - rpath;
133     char *new_rpath;
134    
135     if (resolved) {
136     __set_errno(ENAMETOOLONG);
137     if (dest > rpath + 1)
138     dest--;
139     *dest = '\0';
140     goto error;
141     }
142     new_size = rpath_limit - rpath;
143     if (end - start + 1 > path_max)
144     new_size += end - start + 1;
145     else
146     new_size += path_max;
147     new_rpath = (char *) realloc(rpath, new_size);
148     if (new_rpath == NULL)
149     goto error;
150     rpath = new_rpath;
151     rpath_limit = rpath + new_size;
152    
153     dest = rpath + dest_offset;
154     }
155    
156     dest = __mempcpy(dest, start, end - start);
157     *dest = '\0';
158     }
159     }
160     #if 1
161     if (dest > rpath + 1 && dest[-1] == '/')
162     --dest;
163     #endif
164     *dest = '\0';
165    
166 azarah 29 return resolved ? rpath : memcpy(resolved, rpath, dest - rpath + 1);
167 ferringb 2
168     error:
169     if (resolved)
170 azarah 29 strncpy(resolved, rpath, path_max - 1);
171 ferringb 2 else
172     free(rpath);
173     return NULL;
174     }
175    
176 azarah 29 // vim:noexpandtab noai:cindent ai

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