119 lines
3.3 KiB
C
119 lines
3.3 KiB
C
/* Target directory operands for coreutils
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Copyright 2004-2022 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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#include <config.h>
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#define TARGETDIR_INLINE _GL_EXTERN_INLINE
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#include <targetdir.h>
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#include <attribute.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#ifdef O_PATH
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enum { O_PATHSEARCH = O_PATH };
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#else
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enum { O_PATHSEARCH = O_SEARCH };
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#endif
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/* Must F designate the working directory? */
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ATTRIBUTE_PURE static bool
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must_be_working_directory (char const *f)
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{
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/* Return true for ".", "./.", ".///./", etc. */
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while (*f++ == '.')
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{
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if (*f != '/')
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return !*f;
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while (*++f == '/')
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continue;
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if (!*f)
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return true;
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}
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return false;
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}
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/* Return a file descriptor open to FILE, for use in openat.
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As an optimization, return AT_FDCWD if FILE must be the working directory.
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As a side effect, possibly set *ST to the file's status.
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Fail and set errno if FILE is not a directory.
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On failure return -2 if AT_FDCWD is -1, -1 otherwise. */
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int
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target_directory_operand (char const *file, struct stat *st)
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{
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if (must_be_working_directory (file))
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return AT_FDCWD;
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int fd = -1;
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int try_to_open = 1;
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int stat_result;
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/* On old systems without O_DIRECTORY, like Solaris 10, check with
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stat first lest we try to open a fifo for example and hang. */
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if (!O_DIRECTORY)
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{
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stat_result = stat (file, st);
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if (stat_result == 0)
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{
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try_to_open = S_ISDIR (st->st_mode);
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errno = ENOTDIR;
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}
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else
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{
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/* On EOVERFLOW failure, give up on checking, as there is no
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easy way to check. This should be rare. */
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try_to_open = errno == EOVERFLOW;
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}
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}
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if (try_to_open)
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{
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fd = open (file, O_PATHSEARCH | O_DIRECTORY);
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/* On platforms lacking O_PATH, using O_SEARCH | O_DIRECTORY to
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open an overly-protected non-directory can fail with either
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EACCES or ENOTDIR. Prefer ENOTDIR as it makes for better
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diagnostics. */
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if (O_PATHSEARCH == O_SEARCH && fd < 0 && errno == EACCES)
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errno = (((O_DIRECTORY ? stat (file, st) : stat_result) == 0
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&& !S_ISDIR (st->st_mode))
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? ENOTDIR : EACCES);
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}
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if (!O_DIRECTORY && 0 <= fd)
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{
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/* On old systems like Solaris 10 double check type,
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to ensure we've opened a directory. */
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int err;
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if (fstat (fd, st) == 0
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? !S_ISDIR (st->st_mode) && (err = ENOTDIR, true)
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: (err = errno) != EOVERFLOW)
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{
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close (fd);
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errno = err;
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fd = -1;
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}
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}
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return fd - (AT_FDCWD == -1 && fd < 0);
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}
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