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" ssize_t ___flistxattr(int, char*, size_t);
37
flistxattr(int fd,char * list,size_t size)38 ssize_t flistxattr(int fd, char *list, size_t size) {
39 int saved_errno = errno;
40 ssize_t result = ___flistxattr(fd, list, size);
41
42 if ((result != -1) || (errno != EBADF)) {
43 return result;
44 }
45
46 // fd could be an O_PATH file descriptor, and the kernel
47 // may not directly support fgetxattr() 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 listxattr(buf, list, size);
59 }
60