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/* Target directory operands for coreutils
Copyright 2004-2022 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 <https://www.gnu.org/licenses/>. */
#include <config.h>
#define TARGETDIR_INLINE _GL_EXTERN_INLINE
#include <targetdir.h>
#include <attribute.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <unistd.h>
#ifdef O_PATH
enum { O_PATHSEARCH = O_PATH };
#else
enum { O_PATHSEARCH = O_SEARCH };
#endif
/* Must F designate the working directory? */
ATTRIBUTE_PURE static bool
must_be_working_directory (char const *f)
{
/* Return true for ".", "./.", ".///./", etc. */
while (*f++ == '.')
{
if (*f != '/')
return !*f;
while (*++f == '/')
continue;
if (!*f)
return true;
}
return false;
}
/* Return a file descriptor open to FILE, for use in openat.
As an optimization, return AT_FDCWD if FILE must be the working directory.
As a side effect, possibly set *ST to the file's status.
Fail and set errno if FILE is not a directory.
On failure return -2 if AT_FDCWD is -1, -1 otherwise. */
int
target_directory_operand (char const *file, struct stat *st)
{
if (must_be_working_directory (file))
return AT_FDCWD;
int fd = -1;
int try_to_open = 1;
int stat_result;
/* On old systems without O_DIRECTORY, like Solaris 10, check with
stat first lest we try to open a fifo for example and hang. */
if (!O_DIRECTORY)
{
stat_result = stat (file, st);
if (stat_result == 0)
{
try_to_open = S_ISDIR (st->st_mode);
errno = ENOTDIR;
}
else
{
/* On EOVERFLOW failure, give up on checking, as there is no
easy way to check. This should be rare. */
try_to_open = errno == EOVERFLOW;
}
}
if (try_to_open)
{
fd = open (file, O_PATHSEARCH | O_DIRECTORY);
/* On platforms lacking O_PATH, using O_SEARCH | O_DIRECTORY to
open an overly-protected non-directory can fail with either
EACCES or ENOTDIR. Prefer ENOTDIR as it makes for better
diagnostics. */
if (O_PATHSEARCH == O_SEARCH && fd < 0 && errno == EACCES)
errno = (((O_DIRECTORY ? stat (file, st) : stat_result) == 0
&& !S_ISDIR (st->st_mode))
? ENOTDIR : EACCES);
}
if (!O_DIRECTORY && 0 <= fd)
{
/* On old systems like Solaris 10 double check type,
to ensure we've opened a directory. */
int err;
if (fstat (fd, st) == 0
? !S_ISDIR (st->st_mode) && (err = ENOTDIR, true)
: (err = errno) != EOVERFLOW)
{
close (fd);
errno = err;
fd = -1;
}
}
return fd - (AT_FDCWD == -1 && fd < 0);
}
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