1/* Copyright (C) 2010-2017 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Andreas Schwab <schwab@redhat.com>, 2010.
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 <sys/socket.h>
21
22#include <sysdep-cancel.h>
23#include <sys/syscall.h>
24#include <kernel-features.h>
25
26/* Do not use the recvmmsg syscall on socketcall architectures unless
27 it was added at the same time as the socketcall support or can be
28 assumed to be present. */
29#if defined __ASSUME_SOCKETCALL \
30 && !defined __ASSUME_RECVMMSG_SYSCALL_WITH_SOCKETCALL \
31 && !defined __ASSUME_RECVMMSG_SYSCALL
32# undef __NR_recvmmsg
33#endif
34
35#ifdef __NR_recvmmsg
36int
37recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags,
38 struct timespec *tmo)
39{
40 return SYSCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags, tmo);
41}
42#elif defined __NR_socketcall
43# include <socketcall.h>
44# ifdef __ASSUME_RECVMMSG_SOCKETCALL
45int
46recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags,
47 struct timespec *tmo)
48{
49 return SOCKETCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags, tmo);
50}
51# else
52static int have_recvmmsg;
53
54int
55recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags,
56 struct timespec *tmo)
57{
58 if (__glibc_likely (have_recvmmsg >= 0))
59 {
60 int ret = SOCKETCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags,
61 tmo);
62 /* The kernel returns -EINVAL for unknown socket operations.
63 We need to convert that error to an ENOSYS error. */
64 if (__builtin_expect (ret < 0, 0)
65 && have_recvmmsg == 0
66 && errno == EINVAL)
67 {
68 /* Try another call, this time with an invalid file
69 descriptor and all other parameters cleared. This call
70 will not cause any harm and it will return
71 immediately. */
72 ret = SOCKETCALL_CANCEL (invalid, -1);
73 if (errno == EINVAL)
74 {
75 have_recvmmsg = -1;
76 __set_errno (ENOSYS);
77 }
78 else
79 {
80 have_recvmmsg = 1;
81 __set_errno (EINVAL);
82 }
83 return -1;
84 }
85 return ret;
86 }
87 __set_errno (ENOSYS);
88 return -1;
89}
90# endif /* __ASSUME_RECVMMSG_SOCKETCALL */
91#else
92# include <socket/recvmmsg.c>
93#endif
94