xref: /base/startup/init/ueventd/ueventd_socket.c (revision d9f0492f) 
1/*
2 * Copyright (c) 2021 Huawei Device Co., Ltd.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 *     http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15
16#include <poll.h>
17#include <stdlib.h>
18#include <errno.h>
19#include <unistd.h>
20#include <sys/socket.h>
21#include <linux/netlink.h>
22#include "securec.h"
23#define INIT_LOG_TAG "ueventd"
24#include "init_log.h"
25
26#define UEVENT_SOCKET_BUFF_SIZE (256 * 1024)
27
28int UeventdSocketInit(void)
29{
30    struct sockaddr_nl addr;
31    int buffSize = UEVENT_SOCKET_BUFF_SIZE;
32    int on = 1;
33
34    if (memset_s(&addr, sizeof(addr), 0, sizeof(addr)) != EOK) {
35        INIT_LOGE("Failed to clear socket address");
36        return -1;
37    }
38    addr.nl_family = AF_NETLINK;
39    addr.nl_pid = getpid();
40    addr.nl_groups = 0xffffffff;
41
42    int sockfd = socket(PF_NETLINK, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, NETLINK_KOBJECT_UEVENT);
43    if (sockfd < 0) {
44        INIT_LOGE("Create socket failed, err = %d", errno);
45        return -1;
46    }
47
48    setsockopt(sockfd, SOL_SOCKET, SO_RCVBUFFORCE, &buffSize, sizeof(buffSize));
49    setsockopt(sockfd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
50
51    if (bind(sockfd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
52        INIT_LOGE("Bind socket failed, err = %d", errno);
53#ifndef STARTUP_INIT_TEST
54        close(sockfd);
55        return -1;
56#endif
57    }
58    return sockfd;
59}
60
61ssize_t ReadUeventMessage(int sockFd, char *buffer, size_t length)
62{
63    ssize_t n = -1;
64    struct msghdr msghdr = {};
65    struct iovec iov;
66    struct sockaddr_nl addr;
67    char credMsg[CMSG_SPACE(sizeof(struct ucred))];
68
69    // sanity check
70    if (sockFd < 0 || buffer == NULL) {
71        return n;
72    }
73
74    iov.iov_base = buffer;
75    iov.iov_len = length;
76    msghdr.msg_name = &addr;
77    msghdr.msg_namelen = sizeof(addr);
78    msghdr.msg_iov = &iov;
79    msghdr.msg_iovlen = 1;
80    msghdr.msg_control = credMsg;
81    msghdr.msg_controllen = sizeof(credMsg);
82
83    n = recvmsg(sockFd, &msghdr, 0);
84    if (n <= 0) {
85        return n;
86    }
87    struct cmsghdr *cmsghdr = CMSG_FIRSTHDR(&msghdr);
88    if (cmsghdr == NULL || cmsghdr->cmsg_type != SCM_CREDENTIALS) {
89        INIT_LOGE("Unexpected control message, ignored");
90        // Drop this message
91        *buffer = '\0';
92        n = -1;
93    }
94    return n;
95}
96