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
31 LIST_HEAD(uevent_handler_head, uevent_handler) uevent_handler_list;
32 pthread_mutex_t uevent_handler_list_lock = PTHREAD_MUTEX_INITIALIZER;
33
34 struct 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
40 static int fd = -1;
41
42 /* Returns 0 on failure, 1 on success */
uevent_init()43 int 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
uevent_get_fd()69 int uevent_get_fd()
70 {
71 return fd;
72 }
73
uevent_next_event(char * buffer,int buffer_length)74 int 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
uevent_add_native_handler(void (* handler)(void * data,const char * msg,int msg_len),void * handler_data)103 int 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
uevent_remove_native_handler(void (* handler)(void * data,const char * msg,int msg_len))121 int 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