1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
|
//===-- Linux implementation of recvfrom ----------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "src/sys/socket/recvfrom.h"
#include <linux/net.h> // For SYS_SOCKET socketcall number.
#include <sys/syscall.h> // For syscall numbers.
#include "hdr/types/socklen_t.h"
#include "hdr/types/ssize_t.h"
#include "hdr/types/struct_sockaddr.h"
#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
#include "src/__support/common.h"
#include "src/__support/libc_errno.h"
#include "src/__support/macros/sanitizer.h"
namespace LIBC_NAMESPACE_DECL {
LLVM_LIBC_FUNCTION(ssize_t, recvfrom,
(int sockfd, void *buf, size_t len, int flags,
sockaddr *__restrict src_addr,
socklen_t *__restrict addrlen)) {
// addrlen is a value-result argument. If it's not null, it passes the max
// size of the buffer src_addr to the syscall. After the syscall, it's updated
// to the actual size of the source address. This may be larger than the
// buffer, in which case the buffer contains a truncated result.
size_t srcaddr_sz;
if (src_addr)
srcaddr_sz = *addrlen;
(void)srcaddr_sz; // prevent "set but not used" warning
#ifdef SYS_recvfrom
ssize_t ret = LIBC_NAMESPACE::syscall_impl<ssize_t>(
SYS_recvfrom, sockfd, buf, len, flags, src_addr, addrlen);
#elif defined(SYS_socketcall)
unsigned long sockcall_args[6] = {static_cast<unsigned long>(sockfd),
reinterpret_cast<unsigned long>(buf),
static_cast<unsigned long>(len),
static_cast<unsigned long>(flags),
reinterpret_cast<unsigned long>(src_addr),
static_cast<unsigned long>(addrlen)};
ssize_t ret = LIBC_NAMESPACE::syscall_impl<ssize_t>(
SYS_socketcall, SYS_RECVFROM, sockcall_args);
#else
#error "socket and socketcall syscalls unavailable for this platform."
#endif
if (ret < 0) {
libc_errno = static_cast<int>(-ret);
return -1;
}
MSAN_UNPOISON(buf, ret);
if (src_addr) {
size_t min_src_addr_size = (*addrlen < srcaddr_sz) ? *addrlen : srcaddr_sz;
(void)min_src_addr_size; // prevent "set but not used" warning
MSAN_UNPOISON(src_addr, min_src_addr_size);
}
return ret;
}
} // namespace LIBC_NAMESPACE_DECL
|
