1/*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <hardware_legacy/uevent.h>
18
19#include <malloc.h>
20#include <string.h>
21#include <unistd.h>
22#include <poll.h>
23#include <pthread.h>
24
25#include <sys/socket.h>
26#include <sys/un.h>
27#include <sys/queue.h>
28#include <linux/netlink.h>
29
30
31LIST_HEAD(uevent_handler_head, uevent_handler) uevent_handler_list;
32pthread_mutex_t uevent_handler_list_lock = PTHREAD_MUTEX_INITIALIZER;
33
34struct uevent_handler {
35    void (*handler)(void *data, const char *msg, int msg_len);
36    void *handler_data;
37    LIST_ENTRY(uevent_handler) list;
38};
39
40static int fd = -1;
41
42/* Returns 0 on failure, 1 on success */
43int uevent_init()
44{
45    struct sockaddr_nl addr;
46    int sz = 64*1024;
47    int s;
48
49    memset(&addr, 0, sizeof(addr));
50    addr.nl_family = AF_NETLINK;
51    addr.nl_pid = getpid();
52    addr.nl_groups = 0xffffffff;
53
54    s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
55    if(s < 0)
56        return 0;
57
58    setsockopt(s, SOL_SOCKET, SO_RCVBUFFORCE, &sz, sizeof(sz));
59
60    if(bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
61        close(s);
62        return 0;
63    }
64
65    fd = s;
66    return (fd > 0);
67}
68
69int uevent_get_fd()
70{
71    return fd;
72}
73
74int uevent_next_event(char* buffer, int buffer_length)
75{
76    while (1) {
77        struct pollfd fds;
78        int nr;
79
80        fds.fd = fd;
81        fds.events = POLLIN;
82        fds.revents = 0;
83        nr = poll(&fds, 1, -1);
84
85        if(nr > 0 && (fds.revents & POLLIN)) {
86            int count = recv(fd, buffer, buffer_length, 0);
87            if (count > 0) {
88                struct uevent_handler *h;
89                pthread_mutex_lock(&uevent_handler_list_lock);
90                LIST_FOREACH(h, &uevent_handler_list, list)
91                    h->handler(h->handler_data, buffer, buffer_length);
92                pthread_mutex_unlock(&uevent_handler_list_lock);
93
94                return count;
95            }
96        }
97    }
98
99    // won't get here
100    return 0;
101}
102
103int uevent_add_native_handler(void (*handler)(void *data, const char *msg, int msg_len),
104                             void *handler_data)
105{
106    struct uevent_handler *h;
107
108    h = malloc(sizeof(struct uevent_handler));
109    if (h == NULL)
110        return -1;
111    h->handler = handler;
112    h->handler_data = handler_data;
113
114    pthread_mutex_lock(&uevent_handler_list_lock);
115    LIST_INSERT_HEAD(&uevent_handler_list, h, list);
116    pthread_mutex_unlock(&uevent_handler_list_lock);
117
118    return 0;
119}
120
121int uevent_remove_native_handler(void (*handler)(void *data, const char *msg, int msg_len))
122{
123    struct uevent_handler *h;
124    int err = -1;
125
126    pthread_mutex_lock(&uevent_handler_list_lock);
127    LIST_FOREACH(h, &uevent_handler_list, list) {
128        if (h->handler == handler) {
129            LIST_REMOVE(h, list);
130            err = 0;
131            break;
132       }
133    }
134    pthread_mutex_unlock(&uevent_handler_list_lock);
135
136    return err;
137}
138