1 /*
2  * Copyright (C) 2010 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 <ctype.h>
18 #include <fcntl.h>
19 #include <poll.h>
20 #include <signal.h>
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <string.h>
24 
25 #include <android-base/stringprintf.h>
26 #include <private/android_filesystem_config.h>
27 #include <selinux/selinux.h>
28 
29 #include "ueventd.h"
30 #include "log.h"
31 #include "util.h"
32 #include "devices.h"
33 #include "ueventd_parser.h"
34 #include "property_service.h"
35 
ueventd_main(int argc,char ** argv)36 int ueventd_main(int argc, char **argv)
37 {
38     /*
39      * init sets the umask to 077 for forked processes. We need to
40      * create files with exact permissions, without modification by
41      * the umask.
42      */
43     umask(000);
44 
45     /* Prevent fire-and-forget children from becoming zombies.
46      * If we should need to wait() for some children in the future
47      * (as opposed to none right now), double-forking here instead
48      * of ignoring SIGCHLD may be the better solution.
49      */
50     signal(SIGCHLD, SIG_IGN);
51 
52     open_devnull_stdio();
53     klog_init();
54     klog_set_level(KLOG_NOTICE_LEVEL);
55 
56     NOTICE("ueventd started!\n");
57 
58     selinux_callback cb;
59     cb.func_log = selinux_klog_callback;
60     selinux_set_callback(SELINUX_CB_LOG, cb);
61 
62     std::string hardware = property_get("ro.hardware");
63 
64     ueventd_parse_config_file("/ueventd.rc");
65     ueventd_parse_config_file(android::base::StringPrintf("/ueventd.%s.rc", hardware.c_str()).c_str());
66 
67     device_init();
68 
69     pollfd ufd;
70     ufd.events = POLLIN;
71     ufd.fd = get_device_fd();
72 
73     while (true) {
74         ufd.revents = 0;
75         int nr = poll(&ufd, 1, -1);
76         if (nr <= 0) {
77             continue;
78         }
79         if (ufd.revents & POLLIN) {
80             handle_device_fd();
81         }
82     }
83 
84     return 0;
85 }
86 
get_android_id(const char * id)87 static int get_android_id(const char *id)
88 {
89     unsigned int i;
90     for (i = 0; i < ARRAY_SIZE(android_ids); i++)
91         if (!strcmp(id, android_ids[i].name))
92             return android_ids[i].aid;
93     return -1;
94 }
95 
set_device_permission(int nargs,char ** args)96 void set_device_permission(int nargs, char **args)
97 {
98     char *name;
99     char *attr = 0;
100     mode_t perm;
101     uid_t uid;
102     gid_t gid;
103     int prefix = 0;
104     int wildcard = 0;
105     char *endptr;
106     int ret;
107     char *tmp = 0;
108 
109     if (nargs == 0)
110         return;
111 
112     if (args[0][0] == '#')
113         return;
114 
115     name = args[0];
116 
117     if (!strncmp(name,"/sys/", 5) && (nargs == 5)) {
118         INFO("/sys/ rule %s %s\n",args[0],args[1]);
119         attr = args[1];
120         args++;
121         nargs--;
122     }
123 
124     if (nargs != 4) {
125         ERROR("invalid line ueventd.rc line for '%s'\n", args[0]);
126         return;
127     }
128 
129     /* If path starts with mtd@ lookup the mount number. */
130     if (!strncmp(name, "mtd@", 4)) {
131         int n = mtd_name_to_number(name + 4);
132         if (n >= 0)
133             asprintf(&tmp, "/dev/mtd/mtd%d", n);
134         name = tmp;
135     } else {
136         int len = strlen(name);
137         char *wildcard_chr = strchr(name, '*');
138         if ((name[len - 1] == '*') &&
139             (wildcard_chr == (name + len - 1))) {
140             prefix = 1;
141             name[len - 1] = '\0';
142         } else if (wildcard_chr) {
143             wildcard = 1;
144         }
145     }
146 
147     perm = strtol(args[1], &endptr, 8);
148     if (!endptr || *endptr != '\0') {
149         ERROR("invalid mode '%s'\n", args[1]);
150         free(tmp);
151         return;
152     }
153 
154     ret = get_android_id(args[2]);
155     if (ret < 0) {
156         ERROR("invalid uid '%s'\n", args[2]);
157         free(tmp);
158         return;
159     }
160     uid = ret;
161 
162     ret = get_android_id(args[3]);
163     if (ret < 0) {
164         ERROR("invalid gid '%s'\n", args[3]);
165         free(tmp);
166         return;
167     }
168     gid = ret;
169 
170     add_dev_perms(name, attr, perm, uid, gid, prefix, wildcard);
171     free(tmp);
172 }
173