X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fopenat.c;h=9d2f7d49c2946b5d710a9fee85bacbeef973d9bd;hb=7ef6c64e210ac0979d7e8ac69bc5b5208c2405ab;hp=69d4c23f9add6d9becc19c9fb6535281c833fac2;hpb=14bf04a59fbfa9ae7a9b55f7885ed96a5f0341ac;p=gnulib.git diff --git a/lib/openat.c b/lib/openat.c index 69d4c23f9..9d2f7d49c 100644 --- a/lib/openat.c +++ b/lib/openat.c @@ -1,10 +1,10 @@ /* provide a replacement openat function - Copyright (C) 2004, 2005 Free Software Foundation, Inc. + Copyright (C) 2004-2014 Free Software Foundation, Inc. - This program is free software; you can redistribute it and/or modify + 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 2, or (at your option) - any later version. + 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 @@ -12,32 +12,144 @@ 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, write to the Free Software Foundation, - Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + along with this program. If not, see . */ /* written by Jim Meyering */ -#ifdef HAVE_CONFIG_H -# include +/* If the user's config.h happens to include , let it include only + the system's here, so that orig_openat doesn't recurse to + rpl_openat. */ +#define __need_system_fcntl_h +#include + +/* Get the original definition of open. It might be defined as a macro. */ +#include +#include +#undef __need_system_fcntl_h + +#if HAVE_OPENAT +static int +orig_openat (int fd, char const *filename, int flags, mode_t mode) +{ + return openat (fd, filename, flags, mode); +} #endif -#include "openat.h" +/* Write "fcntl.h" here, not , otherwise OSF/1 5.1 DTK cc eliminates + this include because of the preliminary #include above. */ +#include "fcntl.h" -#include "dirname.h" /* solely for definition of IS_ABSOLUTE_FILE_NAME */ -#include "fcntl--.h" -#include "openat-priv.h" -#include "save-cwd.h" -#include "unistd--.h" +#include "openat.h" #include +#include #include +#include +#include #include +#if HAVE_OPENAT + +/* Like openat, but work around Solaris 9 bugs with trailing slash. */ +int +rpl_openat (int dfd, char const *filename, int flags, ...) +{ + mode_t mode; + int fd; + + mode = 0; + if (flags & O_CREAT) + { + va_list arg; + va_start (arg, flags); + + /* We have to use PROMOTED_MODE_T instead of mode_t, otherwise GCC 4 + creates crashing code when 'mode_t' is smaller than 'int'. */ + mode = va_arg (arg, PROMOTED_MODE_T); + + va_end (arg); + } + +# 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 + 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 + 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_openat (dfd, 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 + 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) + { + /* We know len is positive, since open did not fail with ENOENT. */ + size_t len = strlen (filename); + if (filename[len - 1] == '/') + { + struct stat statbuf; + + if (fstat (fd, &statbuf) >= 0 && !S_ISDIR (statbuf.st_mode)) + { + close (fd); + errno = ENOTDIR; + return -1; + } + } + } +# endif + + return fd; +} + +#else /* !HAVE_OPENAT */ + +# include "dosname.h" /* solely for definition of IS_ABSOLUTE_FILE_NAME */ +# include "openat-priv.h" +# include "save-cwd.h" + /* Replacement for Solaris' openat function. - Simulate it by doing save_cwd/fchdir/open/restore_cwd. - If either the save_cwd or the restore_cwd fails (relatively unlikely, - and usually indicative of a problem that deserves close attention), + First, try to simulate it via open ("/proc/self/fd/FD/FILE"). + Failing that, simulate it by doing save_cwd/fchdir/open/restore_cwd. + If either the save_cwd or the restore_cwd fails (relatively unlikely), then give a diagnostic and exit nonzero. Otherwise, upon failure, set errno and return -1, as openat does. Upon successful completion, return a file descriptor. */ @@ -51,13 +163,9 @@ openat (int fd, char const *file, int flags, ...) 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 nerrower; - we don't know of any practical counterexamples. */ - if (sizeof (mode_t) < sizeof (int)) - mode = va_arg (arg, int); - else - mode = va_arg (arg, mode_t); + /* We have to use PROMOTED_MODE_T instead of mode_t, otherwise GCC 4 + creates crashing code when 'mode_t' is smaller than 'int'. */ + mode = va_arg (arg, PROMOTED_MODE_T); va_end (arg); } @@ -72,13 +180,13 @@ openat (int fd, char const *file, int flags, ...) directory argument. If a previous attempt to restore the current working directory - failed, then we must not even try to access a `.'-relative name. + failed, then we must not even try to access a '.'-relative name. It is the caller's responsibility not to call this function in that case. */ int openat_permissive (int fd, char const *file, int flags, mode_t mode, - int *cwd_errno) + int *cwd_errno) { struct saved_cwd saved_cwd; int saved_errno; @@ -89,149 +197,61 @@ openat_permissive (int fd, char const *file, int flags, mode_t mode, return open (file, flags, mode); { - char *proc_file; - BUILD_PROC_NAME (proc_file, fd, file); - err = open (proc_file, flags, mode); - /* If the syscall succeeds, or if it fails with an unexpected - errno value, then return right away. Otherwise, fall through - and resort to using save_cwd/restore_cwd. */ - if (0 <= err || ! EXPECTED_ERRNO (errno)) - return err; + char buf[OPENAT_BUFFER_SIZE]; + char *proc_file = openat_proc_name (buf, fd, file); + if (proc_file) + { + int open_result = open (proc_file, flags, mode); + int open_errno = errno; + if (proc_file != buf) + free (proc_file); + /* If the syscall succeeds, or if it fails with an unexpected + errno value, then return right away. Otherwise, fall through + and resort to using save_cwd/restore_cwd. */ + if (0 <= open_result || ! EXPECTED_ERRNO (open_errno)) + { + errno = open_errno; + return open_result; + } + } } save_ok = (save_cwd (&saved_cwd) == 0); if (! save_ok) { if (! cwd_errno) - openat_save_fail (errno); + openat_save_fail (errno); *cwd_errno = errno; } - - err = fchdir (fd); - saved_errno = errno; - - if (! err) + if (0 <= fd && fd == saved_cwd.desc) { - err = open (file, flags, mode); - saved_errno = errno; - if (save_ok && restore_cwd (&saved_cwd) != 0) - { - if (! cwd_errno) - openat_restore_fail (errno); - *cwd_errno = errno; - } - } - - free_cwd (&saved_cwd); - errno = saved_errno; - return err; -} - -#if !HAVE_FDOPENDIR - -/* Replacement for Solaris' function by the same name. - - Simulate it by doing save_cwd/fchdir/opendir(".")/restore_cwd. - If either the save_cwd or the restore_cwd fails (relatively unlikely, - and usually indicative of a problem that deserves close attention), - then give a diagnostic and exit nonzero. - Otherwise, this function works just like Solaris' fdopendir. - - W A R N I N G: - Unlike the other fd-related functions here, this one - effectively consumes its FD parameter. The caller should not - close or otherwise manipulate FD if this function returns successfully. */ -DIR * -fdopendir (int fd) -{ - struct saved_cwd saved_cwd; - int saved_errno; - DIR *dir; - - char *proc_file; - BUILD_PROC_NAME (proc_file, fd, "."); - dir = opendir (proc_file); - saved_errno = errno; - - /* If the syscall fails with an expected errno value, resort to - save_cwd/restore_cwd. */ - if (! dir && EXPECTED_ERRNO (saved_errno)) - { - if (save_cwd (&saved_cwd) != 0) - openat_save_fail (errno); - - if (fchdir (fd) != 0) - { - dir = NULL; - saved_errno = errno; - } - else - { - dir = opendir ("."); - saved_errno = errno; - - if (restore_cwd (&saved_cwd) != 0) - openat_restore_fail (errno); - } - + /* If saving the working directory collides with the user's + requested fd, then the user's fd must have been closed to + begin with. */ free_cwd (&saved_cwd); + errno = EBADF; + return -1; } - if (dir) - close (fd); - errno = saved_errno; - return dir; -} - -#endif - -/* Replacement for Solaris' function by the same name. - - Simulate it by doing save_cwd/fchdir/(stat|lstat)/restore_cwd. - If either the save_cwd or the restore_cwd fails (relatively unlikely, - and usually indicative of a problem that deserves close attention), - then give a diagnostic and exit nonzero. - Otherwise, this function works just like Solaris' fstatat. */ -int -fstatat (int fd, char const *file, struct stat *st, int flag) -{ - struct saved_cwd saved_cwd; - int saved_errno; - int err; - - if (fd == AT_FDCWD || IS_ABSOLUTE_FILE_NAME (file)) - return (flag == AT_SYMLINK_NOFOLLOW - ? lstat (file, st) - : stat (file, st)); - - { - char *proc_file; - BUILD_PROC_NAME (proc_file, fd, file); - err = (flag == AT_SYMLINK_NOFOLLOW - ? lstat (proc_file, st) - : stat (proc_file, st)); - /* If the syscall succeeds, or if it fails with an unexpected - errno value, then return right away. Otherwise, fall through - and resort to using save_cwd/restore_cwd. */ - if (0 <= err || ! EXPECTED_ERRNO (errno)) - return err; - } - - if (save_cwd (&saved_cwd) != 0) - openat_save_fail (errno); - err = fchdir (fd); saved_errno = errno; if (! err) { - err = (flag == AT_SYMLINK_NOFOLLOW - ? lstat (file, st) - : stat (file, st)); + err = open (file, flags, mode); saved_errno = errno; - - if (restore_cwd (&saved_cwd) != 0) - openat_restore_fail (errno); + if (save_ok && restore_cwd (&saved_cwd) != 0) + { + if (! cwd_errno) + { + /* Don't write a message to just-created fd 2. */ + saved_errno = errno; + if (err == STDERR_FILENO) + close (err); + openat_restore_fail (saved_errno); + } + *cwd_errno = errno; + } } free_cwd (&saved_cwd); @@ -239,50 +259,28 @@ fstatat (int fd, char const *file, struct stat *st, int flag) return err; } -/* Replacement for Solaris' function by the same name. - - Simulate it by doing save_cwd/fchdir/(unlink|rmdir)/restore_cwd. - If either the save_cwd or the restore_cwd fails (relatively unlikely, - and usually indicative of a problem that deserves close attention), - then give a diagnostic and exit nonzero. - Otherwise, this function works just like Solaris' unlinkat. */ -int -unlinkat (int fd, char const *file, int flag) +/* Return true if our openat implementation must resort to + using save_cwd and restore_cwd. */ +bool +openat_needs_fchdir (void) { - struct saved_cwd saved_cwd; - int saved_errno; - int err; - - if (fd == AT_FDCWD || IS_ABSOLUTE_FILE_NAME (file)) - return (flag == AT_REMOVEDIR ? rmdir (file) : unlink (file)); - - { - char *proc_file; - BUILD_PROC_NAME (proc_file, fd, file); - err = (flag == AT_REMOVEDIR ? rmdir (proc_file) : unlink (proc_file)); - /* If the syscall succeeds, or if it fails with an unexpected - errno value, then return right away. Otherwise, fall through - and resort to using save_cwd/restore_cwd. */ - if (0 <= err || ! EXPECTED_ERRNO (errno)) - return err; - } + bool needs_fchdir = true; + int fd = open ("/", O_SEARCH); - if (save_cwd (&saved_cwd) != 0) - openat_save_fail (errno); - - err = fchdir (fd); - saved_errno = errno; - - if (! err) + if (0 <= fd) { - err = (flag == AT_REMOVEDIR ? rmdir (file) : unlink (file)); - saved_errno = errno; - - if (restore_cwd (&saved_cwd) != 0) - openat_restore_fail (errno); + char buf[OPENAT_BUFFER_SIZE]; + char *proc_file = openat_proc_name (buf, fd, "."); + if (proc_file) + { + needs_fchdir = false; + if (proc_file != buf) + free (proc_file); + } + close (fd); } - free_cwd (&saved_cwd); - errno = saved_errno; - return err; + return needs_fchdir; } + +#endif /* !HAVE_OPENAT */