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
30 LIST_HEAD(uevent_handler_head, uevent_handler) uevent_handler_list;
31 pthread_mutex_t uevent_handler_list_lock = PTHREAD_MUTEX_INITIALIZER;
32
33 struct 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
39 static int fd = -1;
40
41 /* Returns 0 on failure, 1 on success */
uevent_init()42 int 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
uevent_get_fd()68 int uevent_get_fd()
69 {
70 return fd;
71 }
72
uevent_next_event(char * buffer,int buffer_length)73 int 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
uevent_add_native_handler(void (* handler)(void * data,const char * msg,int msg_len),void * handler_data)102 int 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
uevent_remove_native_handler(void (* handler)(void * data,const char * msg,int msg_len))120 int 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