1 /*
2 * Copyright (C) 2019 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 <stdarg.h>
30 #include <fcntl.h>
31
32 #include "private/bionic_fdtrack.h"
33 #include "private/bionic_fortify.h"
34
35 extern "C" int __fcntl(int fd, int cmd, ...);
36 extern "C" int __fcntl64(int, int, ...);
37
fcntl(int fd,int cmd,...)38 int fcntl(int fd, int cmd, ...) {
39 va_list args;
40 va_start(args, cmd);
41 // This is a bit sketchy for LP64, especially because arg can be an int,
42 // but all of our supported 64-bit ABIs pass the argument in a register.
43 void* arg = va_arg(args, void*);
44 va_end(args);
45
46 if (cmd == F_SETFD && (reinterpret_cast<uintptr_t>(arg) & ~FD_CLOEXEC) != 0) {
47 __fortify_fatal("fcntl(F_SETFD) only supports FD_CLOEXEC but was passed %p", arg);
48 }
49
50 #if defined(__LP64__)
51 int rc = __fcntl(fd, cmd, arg);
52 #else
53 // For LP32 we use the fcntl64 system call to signal that we're using struct flock64.
54 int rc = __fcntl64(fd, cmd, arg);
55 #endif
56 if (cmd == F_DUPFD) {
57 return FDTRACK_CREATE_NAME("F_DUPFD", rc);
58 } else if (cmd == F_DUPFD_CLOEXEC) {
59 return FDTRACK_CREATE_NAME("F_DUPFD_CLOEXEC", rc);
60 }
61 return rc;
62 }
63