diff options
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 | } | ||
