ueventd.c revision eb6ffc765b4a2919bbabd3132bf2bd68a4966415 
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#if LOG_UEVENTS
73    /* Ensure we're at a logging level that will show the events */
74    if (klog_get_level() < KLOG_INFO_LEVEL) {
75        klog_set_level(KLOG_INFO_LEVEL);
76    }
77#endif
78
79    INFO("starting ueventd\n");
80
81    /* Respect hardware passed in through the kernel cmd line. Here we will look
82     * for androidboot.hardware param in kernel cmdline, and save its value in
83     * hardware[]. */
84    import_kernel_cmdline(0, import_kernel_nv);
85
86    get_hardware_name(hardware, &revision);
87
88    ueventd_parse_config_file("/ueventd.rc");
89
90    snprintf(tmp, sizeof(tmp), "/ueventd.%s.rc", hardware);
91    ueventd_parse_config_file(tmp);
92
93    device_init();
94
95    ufd.events = POLLIN;
96    ufd.fd = get_device_fd();
97
98    while(1) {
99        ufd.revents = 0;
100        nr = poll(&ufd, 1, -1);
101        if (nr <= 0)
102            continue;
103        if (ufd.revents & POLLIN)
104               handle_device_fd();
105    }
106}
107
108static int get_android_id(const char *id)
109{
110    unsigned int i;
111    for (i = 0; i < ARRAY_SIZE(android_ids); i++)
112        if (!strcmp(id, android_ids[i].name))
113            return android_ids[i].aid;
114    return -1;
115}
116
117void set_device_permission(int nargs, char **args)
118{
119    char *name;
120    char *attr = 0;
121    mode_t perm;
122    uid_t uid;
123    gid_t gid;
124    int prefix = 0;
125    char *endptr;
126    int ret;
127    char *tmp = 0;
128
129    if (nargs == 0)
130        return;
131
132    if (args[0][0] == '#')
133        return;
134
135    name = args[0];
136
137    if (!strncmp(name,"/sys/", 5) && (nargs == 5)) {
138        INFO("/sys/ rule %s %s\n",args[0],args[1]);
139        attr = args[1];
140        args++;
141        nargs--;
142    }
143
144    if (nargs != 4) {
145        ERROR("invalid line ueventd.rc line for '%s'\n", args[0]);
146        return;
147    }
148
149    /* If path starts with mtd@ lookup the mount number. */
150    if (!strncmp(name, "mtd@", 4)) {
151        int n = mtd_name_to_number(name + 4);
152        if (n >= 0)
153            asprintf(&tmp, "/dev/mtd/mtd%d", n);
154        name = tmp;
155    } else {
156        int len = strlen(name);
157        if (name[len - 1] == '*') {
158            prefix = 1;
159            name[len - 1] = '\0';
160        }
161    }
162
163    perm = strtol(args[1], &endptr, 8);
164    if (!endptr || *endptr != '\0') {
165        ERROR("invalid mode '%s'\n", args[1]);
166        free(tmp);
167        return;
168    }
169
170    ret = get_android_id(args[2]);
171    if (ret < 0) {
172        ERROR("invalid uid '%s'\n", args[2]);
173        free(tmp);
174        return;
175    }
176    uid = ret;
177
178    ret = get_android_id(args[3]);
179    if (ret < 0) {
180        ERROR("invalid gid '%s'\n", args[3]);
181        free(tmp);
182        return;
183    }
184    gid = ret;
185
186    add_dev_perms(name, attr, perm, uid, gid, prefix);
187    free(tmp);
188}
189