e1d0810cd7
A continuation of commit 2825f10b7f.
Add O_PATH compatibility support for flistxattr(). This allows
a process to list out all the extended attributes associated with
O_PATH file descriptors.
Change-Id: Ie2285ac7ad2e4eac427ddba6c2d182d41b130f75
59 lines
2.2 KiB
C++
59 lines
2.2 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 <sys/stat.h>
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#include <sys/types.h>
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#include <sys/xattr.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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extern "C" ssize_t ___flistxattr(int, char*, size_t);
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ssize_t flistxattr(int fd, char *list, size_t size) {
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int saved_errno = errno;
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ssize_t result = ___flistxattr(fd, list, size);
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if ((result != -1) || (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 fgetxattr() on such a file descriptor.
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// Use /proc/self/fd instead to emulate this support.
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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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char buf[40];
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snprintf(buf, sizeof(buf), "/proc/self/fd/%d", fd);
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errno = saved_errno;
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return listxattr(buf, list, size);
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}
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