4d215aad85
I'm skeptical about the usefulness of this, but it's in POSIX, it's in glibc (but not iOS), and it is used in some internal source (test runners and container code). Bug: N/A Test: ran tests Change-Id: I92c5398f2a679b21a33fba92bc8e67e3ae2eb76f
71 lines
2.6 KiB
C++
71 lines
2.6 KiB
C++
/*
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* Copyright (C) 2015 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <fcntl.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <errno.h>
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#include <unistd.h>
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#include <stdio.h>
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#include "private/FdPath.h"
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extern "C" int ___fchmod(int, mode_t);
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int fchmod(int fd, mode_t mode) {
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int saved_errno = errno;
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int result = ___fchmod(fd, mode);
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if (result == 0 || errno != EBADF) {
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return result;
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}
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// fd could be an O_PATH file descriptor, and the kernel
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// may not directly support fchmod() on such a file descriptor.
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// Use /proc/self/fd instead to emulate this support.
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// https://sourceware.org/bugzilla/show_bug.cgi?id=14578
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//
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// As of February 2015, there are no kernels which support fchmod
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// on an O_PATH file descriptor, and "man open" documents fchmod
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// on O_PATH file descriptors as returning EBADF.
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int fd_flag = fcntl(fd, F_GETFL);
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if (fd_flag == -1 || (fd_flag & O_PATH) == 0) {
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errno = EBADF;
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return -1;
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}
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errno = saved_errno;
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result = chmod(FdPath(fd).c_str(), mode);
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if (result == -1 && errno == ELOOP) {
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// Linux does not support changing the mode of a symlink.
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// For fchmodat(AT_SYMLINK_NOFOLLOW), POSIX requires a return
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// value of ENOTSUP. Assume that's true here too.
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errno = ENOTSUP;
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}
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return result;
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}
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