util.c revision dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0 
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 <stdarg.h>
18#include <stdlib.h>
19#include <stdio.h>
20#include <string.h>
21#include <fcntl.h>
22#include <ctype.h>
23#include <errno.h>
24
25#include <sys/stat.h>
26#include <sys/types.h>
27#include <sys/socket.h>
28#include <sys/un.h>
29
30/* for ANDROID_SOCKET_* */
31#include <cutils/sockets.h>
32
33#include <private/android_filesystem_config.h>
34
35#include "init.h"
36
37static int log_fd = -1;
38/* Inital log level before init.rc is parsed and this this is reset. */
39static int log_level = LOG_DEFAULT_LEVEL;
40
41
42void log_set_level(int level) {
43    log_level = level;
44}
45
46void log_init(void)
47{
48    static const char *name = "/dev/__kmsg__";
49    if (mknod(name, S_IFCHR | 0600, (1 << 8) | 11) == 0) {
50        log_fd = open(name, O_WRONLY);
51        fcntl(log_fd, F_SETFD, FD_CLOEXEC);
52        unlink(name);
53    }
54}
55
56#define LOG_BUF_MAX 512
57
58void log_write(int level, const char *fmt, ...)
59{
60    char buf[LOG_BUF_MAX];
61    va_list ap;
62
63    if (level > log_level) return;
64    if (log_fd < 0) return;
65
66    va_start(ap, fmt);
67    vsnprintf(buf, LOG_BUF_MAX, fmt, ap);
68    buf[LOG_BUF_MAX - 1] = 0;
69    va_end(ap);
70    write(log_fd, buf, strlen(buf));
71}
72
73/*
74 * android_name_to_id - returns the integer uid/gid associated with the given
75 * name, or -1U on error.
76 */
77static unsigned int android_name_to_id(const char *name)
78{
79    struct android_id_info *info = android_ids;
80    unsigned int n;
81
82    for (n = 0; n < android_id_count; n++) {
83        if (!strcmp(info[n].name, name))
84            return info[n].aid;
85    }
86
87    return -1U;
88}
89
90/*
91 * decode_uid - decodes and returns the given string, which can be either the
92 * numeric or name representation, into the integer uid or gid. Returns -1U on
93 * error.
94 */
95unsigned int decode_uid(const char *s)
96{
97    unsigned int v;
98
99    if (!s || *s == '\0')
100        return -1U;
101    if (isalpha(s[0]))
102        return android_name_to_id(s);
103
104    errno = 0;
105    v = (unsigned int) strtoul(s, 0, 0);
106    if (errno)
107        return -1U;
108    return v;
109}
110
111/*
112 * create_socket - creates a Unix domain socket in ANDROID_SOCKET_DIR
113 * ("/dev/socket") as dictated in init.rc. This socket is inherited by the
114 * daemon. We communicate the file descriptor's value via the environment
115 * variable ANDROID_SOCKET_ENV_PREFIX<name> ("ANDROID_SOCKET_foo").
116 */
117int create_socket(const char *name, int type, mode_t perm, uid_t uid, gid_t gid)
118{
119    struct sockaddr_un addr;
120    int fd, ret;
121
122    fd = socket(PF_UNIX, type, 0);
123    if (fd < 0) {
124        ERROR("Failed to open socket '%s': %s\n", name, strerror(errno));
125        return -1;
126    }
127
128    memset(&addr, 0 , sizeof(addr));
129    addr.sun_family = AF_UNIX;
130    snprintf(addr.sun_path, sizeof(addr.sun_path), ANDROID_SOCKET_DIR"/%s",
131             name);
132
133    ret = unlink(addr.sun_path);
134    if (ret != 0 && errno != ENOENT) {
135        ERROR("Failed to unlink old socket '%s': %s\n", name, strerror(errno));
136        goto out_close;
137    }
138
139    ret = bind(fd, (struct sockaddr *) &addr, sizeof (addr));
140    if (ret) {
141        ERROR("Failed to bind socket '%s': %s\n", name, strerror(errno));
142        goto out_unlink;
143    }
144
145    chown(addr.sun_path, uid, gid);
146    chmod(addr.sun_path, perm);
147
148    INFO("Created socket '%s' with mode '%o', user '%d', group '%d'\n",
149         addr.sun_path, perm, uid, gid);
150
151    return fd;
152
153out_unlink:
154    unlink(addr.sun_path);
155out_close:
156    close(fd);
157    return -1;
158}
159
160/* reads a file, making sure it is terminated with \n \0 */
161void *read_file(const char *fn, unsigned *_sz)
162{
163    char *data;
164    int sz;
165    int fd;
166
167    data = 0;
168    fd = open(fn, O_RDONLY);
169    if(fd < 0) return 0;
170
171    sz = lseek(fd, 0, SEEK_END);
172    if(sz < 0) goto oops;
173
174    if(lseek(fd, 0, SEEK_SET) != 0) goto oops;
175
176    data = (char*) malloc(sz + 2);
177    if(data == 0) goto oops;
178
179    if(read(fd, data, sz) != sz) goto oops;
180    close(fd);
181    data[sz] = '\n';
182    data[sz+1] = 0;
183    if(_sz) *_sz = sz;
184    return data;
185
186oops:
187    close(fd);
188    if(data != 0) free(data);
189    return 0;
190}
191
192void list_init(struct listnode *node)
193{
194    node->next = node;
195    node->prev = node;
196}
197
198void list_add_tail(struct listnode *head, struct listnode *item)
199{
200    item->next = head;
201    item->prev = head->prev;
202    head->prev->next = item;
203    head->prev = item;
204}
205
206void list_remove(struct listnode *item)
207{
208    item->next->prev = item->prev;
209    item->prev->next = item->next;
210}
211
212