1/* Copyright (C) 2008-2017 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@redhat.com>, 2008.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
18
19#include <errno.h>
20#include <signal.h>
21#include <sys/socket.h>
22
23#include <sysdep-cancel.h>
24#include <sys/syscall.h>
25#include <kernel-features.h>
26
27/* Do not use the accept4 syscall on socketcall architectures unless
28 it was added at the same time as the socketcall support or can be
29 assumed to be present. */
30#if defined __ASSUME_SOCKETCALL \
31 && !defined __ASSUME_ACCEPT4_SYSCALL_WITH_SOCKETCALL \
32 && !defined __ASSUME_ACCEPT4_SYSCALL
33# undef __NR_accept4
34#endif
35
36#ifdef __NR_accept4
37int
38accept4 (int fd, __SOCKADDR_ARG addr, socklen_t *addr_len, int flags)
39{
40 return SYSCALL_CANCEL (accept4, fd, addr.__sockaddr__, addr_len, flags);
41}
42#elif defined __NR_socketcall
43# include <socketcall.h>
44# ifdef __ASSUME_ACCEPT4_SOCKETCALL
45int
46accept4 (int fd, __SOCKADDR_ARG addr, socklen_t *addr_len, int flags)
47{
48 return SOCKETCALL_CANCEL (accept4, fd, addr.__sockaddr__, addr_len, flags);
49}
50# else
51static int have_accept4;
52
53int
54accept4 (int fd, __SOCKADDR_ARG addr, socklen_t *addr_len, int flags)
55{
56 if (__glibc_likely (have_accept4 >= 0))
57 {
58 int ret = SOCKETCALL_CANCEL (accept4, fd, addr.__sockaddr__, addr_len,
59 flags);
60 /* The kernel returns -EINVAL for unknown socket operations.
61 We need to convert that error to an ENOSYS error. */
62 if (__builtin_expect (ret < 0, 0)
63 && have_accept4 == 0
64 && errno == EINVAL)
65 {
66 /* Try another call, this time with the FLAGS parameter
67 cleared and an invalid file descriptor. This call will not
68 cause any harm and it will return immediately. */
69 ret = SOCKETCALL_CANCEL (invalid, -1);
70 if (errno == EINVAL)
71 {
72 have_accept4 = -1;
73 __set_errno (ENOSYS);
74 }
75 else
76 {
77 have_accept4 = 1;
78 __set_errno (EINVAL);
79 }
80 return -1;
81 }
82 return ret;
83 }
84 __set_errno (ENOSYS);
85 return -1;
86}
87# endif /* __ASSUME_ACCEPT4_SOCKETCALL */
88#else /* __NR_socketcall */
89int
90accept4 (int fd, __SOCKADDR_ARG addr, socklen_t *addr_len, int flags)
91{
92 __set_errno (ENOSYS);
93 return -1;
94}
95stub_warning (accept4)
96#endif
97