1 /* 2 * Copyright (C) 2015 The Android Open Source Project 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/stat.h> 30 #include <sys/types.h> 31 #include <sys/xattr.h> 32 #include <errno.h> 33 #include <fcntl.h> 34 #include <stdio.h> 35 36 extern "C" int ___fsetxattr(int, const char*, const void*, size_t, int); 37 38 int fsetxattr(int fd, const char* name, const void* value, size_t size, int flags) { 39 int saved_errno = errno; 40 int result = ___fsetxattr(fd, name, value, size, flags); 41 42 if ((result == 0) || (errno != EBADF)) { 43 return result; 44 } 45 46 // fd could be an O_PATH file descriptor, and the kernel 47 // may not directly support fsetxattr() on such a file descriptor. 48 // Use /proc/self/fd instead to emulate this support. 49 int fd_flag = fcntl(fd, F_GETFL); 50 if ((fd_flag == -1) || ((fd_flag & O_PATH) == 0)) { 51 errno = EBADF; 52 return -1; 53 } 54 55 char buf[40]; 56 snprintf(buf, sizeof(buf), "/proc/self/fd/%d", fd); 57 errno = saved_errno; 58 return setxattr(buf, name, value, size, flags); 59 } 60