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Diffstat (limited to 'gl/open.c')
-rw-r--r-- | gl/open.c | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/gl/open.c b/gl/open.c new file mode 100644 index 00000000..13af2746 --- /dev/null +++ b/gl/open.c | |||
@@ -0,0 +1,140 @@ | |||
1 | /* Open a descriptor to a file. | ||
2 | Copyright (C) 2007-2008 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 | #include <config.h> | ||
20 | |||
21 | /* Get the original definition of open. It might be defined as a macro. */ | ||
22 | #define __need_system_fcntl_h | ||
23 | #include <fcntl.h> | ||
24 | #undef __need_system_fcntl_h | ||
25 | #include <sys/types.h> | ||
26 | |||
27 | static inline int | ||
28 | orig_open (const char *filename, int flags, mode_t mode) | ||
29 | { | ||
30 | return open (filename, flags, mode); | ||
31 | } | ||
32 | |||
33 | /* Specification. */ | ||
34 | #include <fcntl.h> | ||
35 | |||
36 | #include <errno.h> | ||
37 | #include <stdarg.h> | ||
38 | #include <string.h> | ||
39 | #include <sys/types.h> | ||
40 | #include <sys/stat.h> | ||
41 | |||
42 | int | ||
43 | open (const char *filename, int flags, ...) | ||
44 | { | ||
45 | mode_t mode; | ||
46 | int fd; | ||
47 | |||
48 | mode = 0; | ||
49 | if (flags & O_CREAT) | ||
50 | { | ||
51 | va_list arg; | ||
52 | va_start (arg, flags); | ||
53 | |||
54 | /* If mode_t is narrower than int, use the promoted type (int), | ||
55 | not mode_t. Use sizeof to guess whether mode_t is narrower; | ||
56 | we don't know of any practical counterexamples. */ | ||
57 | mode = (sizeof (mode_t) < sizeof (int) | ||
58 | ? va_arg (arg, int) | ||
59 | : va_arg (arg, mode_t)); | ||
60 | |||
61 | va_end (arg); | ||
62 | } | ||
63 | |||
64 | #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__ | ||
65 | if (strcmp (filename, "/dev/null") == 0) | ||
66 | filename = "NUL"; | ||
67 | #endif | ||
68 | |||
69 | #if OPEN_TRAILING_SLASH_BUG | ||
70 | /* If the filename ends in a slash and one of O_CREAT, O_WRONLY, O_RDWR | ||
71 | is specified, then fail. | ||
72 | Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html> | ||
73 | says that | ||
74 | "A pathname that contains at least one non-slash character and that | ||
75 | ends with one or more trailing slashes shall be resolved as if a | ||
76 | single dot character ( '.' ) were appended to the pathname." | ||
77 | and | ||
78 | "The special filename dot shall refer to the directory specified by | ||
79 | its predecessor." | ||
80 | If the named file already exists as a directory, then | ||
81 | - if O_CREAT is specified, open() must fail because of the semantics | ||
82 | of O_CREAT, | ||
83 | - if O_WRONLY or O_RDWR is specified, open() must fail because POSIX | ||
84 | <http://www.opengroup.org/susv3/functions/open.html> says that it | ||
85 | fails with errno = EISDIR in this case. | ||
86 | If the named file does not exist or does not name a directory, then | ||
87 | - if O_CREAT is specified, open() must fail since open() cannot create | ||
88 | directories, | ||
89 | - if O_WRONLY or O_RDWR is specified, open() must fail because the | ||
90 | file does not contain a '.' directory. */ | ||
91 | if (flags & (O_CREAT | O_WRONLY | O_RDWR)) | ||
92 | { | ||
93 | size_t len = strlen (filename); | ||
94 | if (len > 0 && filename[len - 1] == '/') | ||
95 | { | ||
96 | errno = EISDIR; | ||
97 | return -1; | ||
98 | } | ||
99 | } | ||
100 | #endif | ||
101 | |||
102 | fd = orig_open (filename, flags, mode); | ||
103 | |||
104 | #if OPEN_TRAILING_SLASH_BUG | ||
105 | /* If the filename ends in a slash and fd does not refer to a directory, | ||
106 | then fail. | ||
107 | Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html> | ||
108 | says that | ||
109 | "A pathname that contains at least one non-slash character and that | ||
110 | ends with one or more trailing slashes shall be resolved as if a | ||
111 | single dot character ( '.' ) were appended to the pathname." | ||
112 | and | ||
113 | "The special filename dot shall refer to the directory specified by | ||
114 | its predecessor." | ||
115 | If the named file without the slash is not a directory, open() must fail | ||
116 | with ENOTDIR. */ | ||
117 | if (fd >= 0) | ||
118 | { | ||
119 | size_t len = strlen (filename); | ||
120 | if (len > 0 && filename[len - 1] == '/') | ||
121 | { | ||
122 | struct stat statbuf; | ||
123 | |||
124 | if (fstat (fd, &statbuf) >= 0 && !S_ISDIR (statbuf.st_mode)) | ||
125 | { | ||
126 | close (fd); | ||
127 | errno = ENOTDIR; | ||
128 | return -1; | ||
129 | } | ||
130 | } | ||
131 | } | ||
132 | #endif | ||
133 | |||
134 | #ifdef FCHDIR_REPLACEMENT | ||
135 | if (fd >= 0) | ||
136 | _gl_register_fd (fd, filename); | ||
137 | #endif | ||
138 | |||
139 | return fd; | ||
140 | } | ||