ueventd.c revision 6ebf12fe1bc2de7af4522349973e8bfcc71d6126 
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 <poll.h>
18#include <fcntl.h>
19#include <string.h>
20#include <stdlib.h>
21#include <stdio.h>
22#include <ctype.h>
23#include <signal.h>
24
25#include <private/android_filesystem_config.h>
26
27#include "ueventd.h"
28#include "log.h"
29#include "util.h"
30#include "devices.h"
31#include "ueventd_parser.h"
32
33static char hardware[32];
34static unsigned revision = 0;
35
36static void import_kernel_nv(char *name, int in_qemu)
37{
38    if (*name != '\0') {
39        char *value = strchr(name, '=');
40        if (value != NULL) {
41            *value++ = 0;
42            if (!strcmp(name,"androidboot.hardware"))
43            {
44                strlcpy(hardware, value, sizeof(hardware));
45            }
46        }
47    }
48}
49
50int ueventd_main(int argc, char **argv)
51{
52    struct pollfd ufd;
53    int nr;
54    char tmp[32];
55
56    /*
57     * init sets the umask to 077 for forked processes. We need to
58     * create files with exact permissions, without modification by
59     * the umask.
60     */
61    umask(000);
62
63    /* Prevent fire-and-forget children from becoming zombies.
64     * If we should need to wait() for some children in the future
65     * (as opposed to none right now), double-forking here instead
66     * of ignoring SIGCHLD may be the better solution.
67     */
68    signal(SIGCHLD, SIG_IGN);
69
70    open_devnull_stdio();
71    klog_init();
72
73    INFO("starting ueventd\n");
74
75    /* Respect hardware passed in through the kernel cmd line. Here we will look
76     * for androidboot.hardware param in kernel cmdline, and save its value in
77     * hardware[]. */
78    import_kernel_cmdline(0, import_kernel_nv);
79
80    get_hardware_name(hardware, &revision);
81
82    ueventd_parse_config_file("/ueventd.rc");
83
84    snprintf(tmp, sizeof(tmp), "/ueventd.%s.rc", hardware);
85    ueventd_parse_config_file(tmp);
86
87    device_init();
88
89    ufd.events = POLLIN;
90    ufd.fd = get_device_fd();
91
92    while(1) {
93        ufd.revents = 0;
94        nr = poll(&ufd, 1, -1);
95        if (nr <= 0)
96            continue;
97        if (ufd.revents == POLLIN)
98               handle_device_fd();
99    }
100}
101
102static int get_android_id(const char *id)
103{
104    unsigned int i;
105    for (i = 0; i < ARRAY_SIZE(android_ids); i++)
106        if (!strcmp(id, android_ids[i].name))
107            return android_ids[i].aid;
108    return 0;
109}
110
111void set_device_permission(int nargs, char **args)
112{
113    char *name;
114    char *attr = 0;
115    mode_t perm;
116    uid_t uid;
117    gid_t gid;
118    int prefix = 0;
119    char *endptr;
120    int ret;
121    char *tmp = 0;
122
123    if (nargs == 0)
124        return;
125
126    if (args[0][0] == '#')
127        return;
128
129    name = args[0];
130
131    if (!strncmp(name,"/sys/", 5) && (nargs == 5)) {
132        INFO("/sys/ rule %s %s\n",args[0],args[1]);
133        attr = args[1];
134        args++;
135        nargs--;
136    }
137
138    if (nargs != 4) {
139        ERROR("invalid line ueventd.rc line for '%s'\n", args[0]);
140        return;
141    }
142
143    /* If path starts with mtd@ lookup the mount number. */
144    if (!strncmp(name, "mtd@", 4)) {
145        int n = mtd_name_to_number(name + 4);
146        if (n >= 0)
147            asprintf(&tmp, "/dev/mtd/mtd%d", n);
148        name = tmp;
149    } else {
150        int len = strlen(name);
151        if (name[len - 1] == '*') {
152            prefix = 1;
153            name[len - 1] = '\0';
154        }
155    }
156
157    perm = strtol(args[1], &endptr, 8);
158    if (!endptr || *endptr != '\0') {
159        ERROR("invalid mode '%s'\n", args[1]);
160        free(tmp);
161        return;
162    }
163
164    ret = get_android_id(args[2]);
165    if (ret < 0) {
166        ERROR("invalid uid '%s'\n", args[2]);
167        free(tmp);
168        return;
169    }
170    uid = ret;
171
172    ret = get_android_id(args[3]);
173    if (ret < 0) {
174        ERROR("invalid gid '%s'\n", args[3]);
175        free(tmp);
176        return;
177    }
178    gid = ret;
179
180    add_dev_perms(name, attr, perm, uid, gid, prefix);
181    free(tmp);
182}
183