platform_bionic/libc/bionic/fchmodat.cpp
Elliott Hughes 50080a29f7 Remove the ___ hack.
Plain __ for generated syscalls didn't mean it was a hidden symbol, it
just meant "please don't use this". We added ___ to signify that a
hidden symbol should be generated, but then we added the map files
anyway so you now have to explicitly export symbols. Given that, this
convention serves no particular purpose so we may as well just use the
nicer names have everything look the same.

Test: treehugger
Change-Id: If424e17a49c36f4be545f5d283c4561a6ea9c7ea
2019-06-19 15:38:42 -07:00

67 lines
2.5 KiB
C++

/*
* Copyright (C) 2015 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <errno.h>
#include <unistd.h>
#include "private/ErrnoRestorer.h"
extern "C" int __fchmodat(int, const char*, mode_t);
int fchmodat(int dirfd, const char* pathname, mode_t mode, int flags) {
if ((flags & ~AT_SYMLINK_NOFOLLOW) != 0) {
errno = EINVAL;
return -1;
}
if (flags & AT_SYMLINK_NOFOLLOW) {
// Emulate AT_SYMLINK_NOFOLLOW using the mechanism described
// at https://sourceware.org/bugzilla/show_bug.cgi?id=14578
// comment #10
int fd = openat(dirfd, pathname, O_PATH | O_NOFOLLOW | O_CLOEXEC);
if (fd == -1) {
return -1; // returns errno from openat
}
// POSIX requires that ENOTSUP be returned when the system
// doesn't support setting the mode of a symbolic link.
// This is true for all Linux kernels.
// We rely on the O_PATH compatibility layer added in the
// fchmod() function to get errno correct.
int result = fchmod(fd, mode);
ErrnoRestorer errno_restorer; // don't let close() clobber errno
close(fd);
return result;
}
return __fchmodat(dirfd, pathname, mode);
}