util.c revision cd0f173e2790ee068fd2a20bcfc6c20468e97e51 
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#include <time.h>
25
26#include <sys/stat.h>
27#include <sys/types.h>
28#include <sys/socket.h>
29#include <sys/un.h>
30
31/* for ANDROID_SOCKET_* */
32#include <cutils/sockets.h>
33
34#include <private/android_filesystem_config.h>
35
36#include "log.h"
37#include "list.h"
38
39static int log_fd = -1;
40/* Inital log level before init.rc is parsed and this this is reset. */
41static int log_level = LOG_DEFAULT_LEVEL;
42
43
44void log_set_level(int level) {
45    log_level = level;
46}
47
48void log_init(void)
49{
50    static const char *name = "/dev/__kmsg__";
51    if (mknod(name, S_IFCHR | 0600, (1 << 8) | 11) == 0) {
52        log_fd = open(name, O_WRONLY);
53        fcntl(log_fd, F_SETFD, FD_CLOEXEC);
54        unlink(name);
55    }
56}
57
58#define LOG_BUF_MAX 512
59
60void log_write(int level, const char *fmt, ...)
61{
62    char buf[LOG_BUF_MAX];
63    va_list ap;
64
65    if (level > log_level) return;
66    if (log_fd < 0) return;
67
68    va_start(ap, fmt);
69    vsnprintf(buf, LOG_BUF_MAX, fmt, ap);
70    buf[LOG_BUF_MAX - 1] = 0;
71    va_end(ap);
72    write(log_fd, buf, strlen(buf));
73}
74
75/*
76 * android_name_to_id - returns the integer uid/gid associated with the given
77 * name, or -1U on error.
78 */
79static unsigned int android_name_to_id(const char *name)
80{
81    struct android_id_info *info = android_ids;
82    unsigned int n;
83
84    for (n = 0; n < android_id_count; n++) {
85        if (!strcmp(info[n].name, name))
86            return info[n].aid;
87    }
88
89    return -1U;
90}
91
92/*
93 * decode_uid - decodes and returns the given string, which can be either the
94 * numeric or name representation, into the integer uid or gid. Returns -1U on
95 * error.
96 */
97unsigned int decode_uid(const char *s)
98{
99    unsigned int v;
100
101    if (!s || *s == '\0')
102        return -1U;
103    if (isalpha(s[0]))
104        return android_name_to_id(s);
105
106    errno = 0;
107    v = (unsigned int) strtoul(s, 0, 0);
108    if (errno)
109        return -1U;
110    return v;
111}
112
113/*
114 * create_socket - creates a Unix domain socket in ANDROID_SOCKET_DIR
115 * ("/dev/socket") as dictated in init.rc. This socket is inherited by the
116 * daemon. We communicate the file descriptor's value via the environment
117 * variable ANDROID_SOCKET_ENV_PREFIX<name> ("ANDROID_SOCKET_foo").
118 */
119int create_socket(const char *name, int type, mode_t perm, uid_t uid, gid_t gid)
120{
121    struct sockaddr_un addr;
122    int fd, ret;
123
124    fd = socket(PF_UNIX, type, 0);
125    if (fd < 0) {
126        ERROR("Failed to open socket '%s': %s\n", name, strerror(errno));
127        return -1;
128    }
129
130    memset(&addr, 0 , sizeof(addr));
131    addr.sun_family = AF_UNIX;
132    snprintf(addr.sun_path, sizeof(addr.sun_path), ANDROID_SOCKET_DIR"/%s",
133             name);
134
135    ret = unlink(addr.sun_path);
136    if (ret != 0 && errno != ENOENT) {
137        ERROR("Failed to unlink old socket '%s': %s\n", name, strerror(errno));
138        goto out_close;
139    }
140
141    ret = bind(fd, (struct sockaddr *) &addr, sizeof (addr));
142    if (ret) {
143        ERROR("Failed to bind socket '%s': %s\n", name, strerror(errno));
144        goto out_unlink;
145    }
146
147    chown(addr.sun_path, uid, gid);
148    chmod(addr.sun_path, perm);
149
150    INFO("Created socket '%s' with mode '%o', user '%d', group '%d'\n",
151         addr.sun_path, perm, uid, gid);
152
153    return fd;
154
155out_unlink:
156    unlink(addr.sun_path);
157out_close:
158    close(fd);
159    return -1;
160}
161
162/* reads a file, making sure it is terminated with \n \0 */
163void *read_file(const char *fn, unsigned *_sz)
164{
165    char *data;
166    int sz;
167    int fd;
168
169    data = 0;
170    fd = open(fn, O_RDONLY);
171    if(fd < 0) return 0;
172
173    sz = lseek(fd, 0, SEEK_END);
174    if(sz < 0) goto oops;
175
176    if(lseek(fd, 0, SEEK_SET) != 0) goto oops;
177
178    data = (char*) malloc(sz + 2);
179    if(data == 0) goto oops;
180
181    if(read(fd, data, sz) != sz) goto oops;
182    close(fd);
183    data[sz] = '\n';
184    data[sz+1] = 0;
185    if(_sz) *_sz = sz;
186    return data;
187
188oops:
189    close(fd);
190    if(data != 0) free(data);
191    return 0;
192}
193
194void list_init(struct listnode *node)
195{
196    node->next = node;
197    node->prev = node;
198}
199
200void list_add_tail(struct listnode *head, struct listnode *item)
201{
202    item->next = head;
203    item->prev = head->prev;
204    head->prev->next = item;
205    head->prev = item;
206}
207
208void list_remove(struct listnode *item)
209{
210    item->next->prev = item->prev;
211    item->prev->next = item->next;
212}
213
214#define MAX_MTD_PARTITIONS 16
215
216static struct {
217    char name[16];
218    int number;
219} mtd_part_map[MAX_MTD_PARTITIONS];
220
221static int mtd_part_count = -1;
222
223static void find_mtd_partitions(void)
224{
225    int fd;
226    char buf[1024];
227    char *pmtdbufp;
228    ssize_t pmtdsize;
229    int r;
230
231    fd = open("/proc/mtd", O_RDONLY);
232    if (fd < 0)
233        return;
234
235    buf[sizeof(buf) - 1] = '\0';
236    pmtdsize = read(fd, buf, sizeof(buf) - 1);
237    pmtdbufp = buf;
238    while (pmtdsize > 0) {
239        int mtdnum, mtdsize, mtderasesize;
240        char mtdname[16];
241        mtdname[0] = '\0';
242        mtdnum = -1;
243        r = sscanf(pmtdbufp, "mtd%d: %x %x %15s",
244                   &mtdnum, &mtdsize, &mtderasesize, mtdname);
245        if ((r == 4) && (mtdname[0] == '"')) {
246            char *x = strchr(mtdname + 1, '"');
247            if (x) {
248                *x = 0;
249            }
250            INFO("mtd partition %d, %s\n", mtdnum, mtdname + 1);
251            if (mtd_part_count < MAX_MTD_PARTITIONS) {
252                strcpy(mtd_part_map[mtd_part_count].name, mtdname + 1);
253                mtd_part_map[mtd_part_count].number = mtdnum;
254                mtd_part_count++;
255            } else {
256                ERROR("too many mtd partitions\n");
257            }
258        }
259        while (pmtdsize > 0 && *pmtdbufp != '\n') {
260            pmtdbufp++;
261            pmtdsize--;
262        }
263        if (pmtdsize > 0) {
264            pmtdbufp++;
265            pmtdsize--;
266        }
267    }
268    close(fd);
269}
270
271int mtd_name_to_number(const char *name)
272{
273    int n;
274    if (mtd_part_count < 0) {
275        mtd_part_count = 0;
276        find_mtd_partitions();
277    }
278    for (n = 0; n < mtd_part_count; n++) {
279        if (!strcmp(name, mtd_part_map[n].name)) {
280            return mtd_part_map[n].number;
281        }
282    }
283    return -1;
284}
285
286/*
287 * gettime() - returns the time in seconds of the system's monotonic clock or
288 * zero on error.
289 */
290time_t gettime(void)
291{
292    struct timespec ts;
293    int ret;
294
295    ret = clock_gettime(CLOCK_MONOTONIC, &ts);
296    if (ret < 0) {
297        ERROR("clock_gettime(CLOCK_MONOTONIC) failed: %s\n", strerror(errno));
298        return 0;
299    }
300
301    return ts.tv_sec;
302}
303
304int mkdir_recursive(const char *pathname, mode_t mode)
305{
306    char buf[128];
307    const char *slash;
308    const char *p = pathname;
309    int width;
310    int ret;
311    struct stat info;
312
313    while ((slash = strchr(p, '/')) != NULL) {
314        width = slash - pathname;
315        p = slash + 1;
316        if (width < 0)
317            break;
318        if (width == 0)
319            continue;
320        if ((unsigned int)width > sizeof(buf) - 1) {
321            ERROR("path too long for mkdir_recursive\n");
322            return -1;
323        }
324        memcpy(buf, pathname, width);
325        buf[width] = 0;
326        if (stat(buf, &info) != 0) {
327            ret = mkdir(buf, mode);
328            if (ret && errno != EEXIST)
329                return ret;
330        }
331    }
332    ret = mkdir(pathname, mode);
333    if (ret && errno != EEXIST)
334        return ret;
335    return 0;
336}
337
338void sanitize(char *s)
339{
340    if (!s)
341        return;
342    while (isalnum(*s))
343        s++;
344    *s = 0;
345}
346void make_link(const char *oldpath, const char *newpath)
347{
348    int ret;
349    char buf[256];
350    char *slash;
351    int width;
352
353    slash = strrchr(newpath, '/');
354    if (!slash)
355        return;
356    width = slash - newpath;
357    if (width <= 0 || width > (int)sizeof(buf) - 1)
358        return;
359    memcpy(buf, newpath, width);
360    buf[width] = 0;
361    ret = mkdir_recursive(buf, 0755);
362    if (ret)
363        ERROR("Failed to create directory %s: %s (%d)\n", buf, strerror(errno), errno);
364
365    ret = symlink(oldpath, newpath);
366    if (ret && errno != EEXIST)
367        ERROR("Failed to symlink %s to %s: %s (%d)\n", oldpath, newpath, strerror(errno), errno);
368}
369
370void remove_link(const char *oldpath, const char *newpath)
371{
372    char path[256];
373    ssize_t ret;
374    ret = readlink(newpath, path, sizeof(path) - 1);
375    if (ret <= 0)
376        return;
377    path[ret] = 0;
378    if (!strcmp(path, oldpath))
379        unlink(newpath);
380}
381
382int wait_for_file(const char *filename, int timeout)
383{
384    struct stat info;
385    time_t timeout_time = gettime() + timeout;
386    int ret = -1;
387
388    while (gettime() < timeout_time && ((ret = stat(filename, &info)) < 0))
389        usleep(10000);
390
391    return ret;
392}
393