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 <string.h>
20#include <unistd.h>
21#include <poll.h>
22#include <pthread.h>
23
24#include <sys/socket.h>
25#include <sys/un.h>
26#include <sys/queue.h>
27#include <linux/netlink.h>
28
29
30LIST_HEAD(uevent_handler_head, uevent_handler) uevent_handler_list;
31pthread_mutex_t uevent_handler_list_lock = PTHREAD_MUTEX_INITIALIZER;
32
33struct uevent_handler {
34    void (*handler)(void *data, const char *msg, int msg_len);
35    void *handler_data;
36    LIST_ENTRY(uevent_handler) list;
37};
38
39static int fd = -1;
40
41/* Returns 0 on failure, 1 on success */
42int uevent_init()
43{
44    struct sockaddr_nl addr;
45    int sz = 64*1024;
46    int s;
47
48    memset(&addr, 0, sizeof(addr));
49    addr.nl_family = AF_NETLINK;
50    addr.nl_pid = getpid();
51    addr.nl_groups = 0xffffffff;
52
53    s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
54    if(s < 0)
55        return 0;
56
57    setsockopt(s, SOL_SOCKET, SO_RCVBUFFORCE, &sz, sizeof(sz));
58
59    if(bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
60        close(s);
61        return 0;
62    }
63
64    fd = s;
65    return (fd > 0);
66}
67
68int uevent_get_fd()
69{
70    return fd;
71}
72
73int uevent_next_event(char* buffer, int buffer_length)
74{
75    while (1) {
76        struct pollfd fds;
77        int nr;
78
79        fds.fd = fd;
80        fds.events = POLLIN;
81        fds.revents = 0;
82        nr = poll(&fds, 1, -1);
83
84        if(nr > 0 && (fds.revents & POLLIN)) {
85            int count = recv(fd, buffer, buffer_length, 0);
86            if (count > 0) {
87                struct uevent_handler *h;
88                pthread_mutex_lock(&uevent_handler_list_lock);
89                LIST_FOREACH(h, &uevent_handler_list, list)
90                    h->handler(h->handler_data, buffer, buffer_length);
91                pthread_mutex_unlock(&uevent_handler_list_lock);
92
93                return count;
94            }
95        }
96    }
97
98    // won't get here
99    return 0;
100}
101
102int uevent_add_native_handler(void (*handler)(void *data, const char *msg, int msg_len),
103                             void *handler_data)
104{
105    struct uevent_handler *h;
106
107    h = malloc(sizeof(struct uevent_handler));
108    if (h == NULL)
109        return -1;
110    h->handler = handler;
111    h->handler_data = handler_data;
112
113    pthread_mutex_lock(&uevent_handler_list_lock);
114    LIST_INSERT_HEAD(&uevent_handler_list, h, list);
115    pthread_mutex_unlock(&uevent_handler_list_lock);
116
117    return 0;
118}
119
120int uevent_remove_native_handler(void (*handler)(void *data, const char *msg, int msg_len))
121{
122    struct uevent_handler *h;
123    int err = -1;
124
125    pthread_mutex_lock(&uevent_handler_list_lock);
126    LIST_FOREACH(h, &uevent_handler_list, list) {
127        if (h->handler == handler) {
128            LIST_REMOVE(h, list);
129            err = 0;
130            break;
131       }
132    }
133    pthread_mutex_unlock(&uevent_handler_list_lock);
134
135    return err;
136}
137