1 /* Open a stream to a file.
2 Copyright (C) 2007-2012 Free Software Foundation, Inc.
3
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 3 of the License, or
7 (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
16
17 /* Written by Bruno Haible <bruno@clisp.org>, 2007. */
18
19 /* If the user's config.h happens to include <stdio.h>, let it include only
20 the system's <stdio.h> here, so that orig_fopen doesn't recurse to
21 rpl_fopen. */
22 #define __need_FILE
23 #include <config.h>
24
25 /* Get the original definition of fopen. It might be defined as a macro. */
26 #include <stdio.h>
27 #undef __need_FILE
28
29 static FILE *
orig_fopen(const char * filename,const char * mode)30 orig_fopen (const char *filename, const char *mode)
31 {
32 return fopen (filename, mode);
33 }
34
35 /* Specification. */
36 /* Write "stdio.h" here, not <stdio.h>, otherwise OSF/1 5.1 DTK cc eliminates
37 this include because of the preliminary #include <stdio.h> above. */
38 #include "stdio.h"
39
40 #include <errno.h>
41 #include <fcntl.h>
42 #include <string.h>
43 #include <unistd.h>
44 #include <sys/types.h>
45 #include <sys/stat.h>
46
47 FILE *
rpl_fopen(const char * filename,const char * mode)48 rpl_fopen (const char *filename, const char *mode)
49 {
50 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
51 if (strcmp (filename, "/dev/null") == 0)
52 filename = "NUL";
53 #endif
54
55 #if FOPEN_TRAILING_SLASH_BUG
56 /* If the filename ends in a slash and a mode that requires write access is
57 specified, then fail.
58 Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html>
59 says that
60 "A pathname that contains at least one non-slash character and that
61 ends with one or more trailing slashes shall be resolved as if a
62 single dot character ( '.' ) were appended to the pathname."
63 and
64 "The special filename dot shall refer to the directory specified by
65 its predecessor."
66 If the named file already exists as a directory, then if a mode that
67 requires write access is specified, fopen() must fail because POSIX
68 <http://www.opengroup.org/susv3/functions/fopen.html> says that it
69 fails with errno = EISDIR in this case.
70 If the named file does not exist or does not name a directory, then
71 fopen() must fail since the file does not contain a '.' directory. */
72 {
73 size_t len = strlen (filename);
74 if (len > 0 && filename[len - 1] == '/')
75 {
76 int fd;
77 struct stat statbuf;
78 FILE *fp;
79
80 if (mode[0] == 'w' || mode[0] == 'a')
81 {
82 errno = EISDIR;
83 return NULL;
84 }
85
86 fd = open (filename, O_RDONLY);
87 if (fd < 0)
88 return NULL;
89
90 if (fstat (fd, &statbuf) >= 0 && !S_ISDIR (statbuf.st_mode))
91 {
92 close (fd);
93 errno = ENOTDIR;
94 return NULL;
95 }
96
97 fp = fdopen (fd, mode);
98 if (fp == NULL)
99 {
100 int saved_errno = errno;
101 close (fd);
102 errno = saved_errno;
103 }
104 return fp;
105 }
106 }
107 # endif
108
109 return orig_fopen (filename, mode);
110 }
111