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 @@ +/* Open a descriptor to a file. + Copyright (C) 2007-2008 Free Software Foundation, Inc. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. */ + +/* Written by Bruno Haible <bruno@clisp.org>, 2007. */ + +#include <config.h> + +/* Get the original definition of open. It might be defined as a macro. */ +#define __need_system_fcntl_h +#include <fcntl.h> +#undef __need_system_fcntl_h +#include <sys/types.h> + +static inline int +orig_open (const char *filename, int flags, mode_t mode) +{ + return open (filename, flags, mode); +} + +/* Specification. */ +#include <fcntl.h> + +#include <errno.h> +#include <stdarg.h> +#include <string.h> +#include <sys/types.h> +#include <sys/stat.h> + +int +open (const char *filename, int flags, ...) +{ + mode_t mode; + int fd; + + mode = 0; + if (flags & O_CREAT) + { + va_list arg; + va_start (arg, flags); + + /* If mode_t is narrower than int, use the promoted type (int), + not mode_t. Use sizeof to guess whether mode_t is narrower; + we don't know of any practical counterexamples. */ + mode = (sizeof (mode_t) < sizeof (int) + ? va_arg (arg, int) + : va_arg (arg, mode_t)); + + va_end (arg); + } + +#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__ + if (strcmp (filename, "/dev/null") == 0) + filename = "NUL"; +#endif + +#if OPEN_TRAILING_SLASH_BUG + /* If the filename ends in a slash and one of O_CREAT, O_WRONLY, O_RDWR + is specified, then fail. + Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html> + says that + "A pathname that contains at least one non-slash character and that + ends with one or more trailing slashes shall be resolved as if a + single dot character ( '.' ) were appended to the pathname." + and + "The special filename dot shall refer to the directory specified by + its predecessor." + If the named file already exists as a directory, then + - if O_CREAT is specified, open() must fail because of the semantics + of O_CREAT, + - if O_WRONLY or O_RDWR is specified, open() must fail because POSIX + <http://www.opengroup.org/susv3/functions/open.html> says that it + fails with errno = EISDIR in this case. + If the named file does not exist or does not name a directory, then + - if O_CREAT is specified, open() must fail since open() cannot create + directories, + - if O_WRONLY or O_RDWR is specified, open() must fail because the + file does not contain a '.' directory. */ + if (flags & (O_CREAT | O_WRONLY | O_RDWR)) + { + size_t len = strlen (filename); + if (len > 0 && filename[len - 1] == '/') + { + errno = EISDIR; + return -1; + } + } +#endif + + fd = orig_open (filename, flags, mode); + +#if OPEN_TRAILING_SLASH_BUG + /* If the filename ends in a slash and fd does not refer to a directory, + then fail. + Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html> + says that + "A pathname that contains at least one non-slash character and that + ends with one or more trailing slashes shall be resolved as if a + single dot character ( '.' ) were appended to the pathname." + and + "The special filename dot shall refer to the directory specified by + its predecessor." + If the named file without the slash is not a directory, open() must fail + with ENOTDIR. */ + if (fd >= 0) + { + size_t len = strlen (filename); + if (len > 0 && filename[len - 1] == '/') + { + struct stat statbuf; + + if (fstat (fd, &statbuf) >= 0 && !S_ISDIR (statbuf.st_mode)) + { + close (fd); + errno = ENOTDIR; + return -1; + } + } + } +#endif + +#ifdef FCHDIR_REPLACEMENT + if (fd >= 0) + _gl_register_fd (fd, filename); +#endif + + return fd; +} |