util.c revision b0ab94b7d5a888f0b6920b156e5c6a075fa0741a 
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 "init.h"
37
38static int log_fd = -1;
39/* Inital log level before init.rc is parsed and this this is reset. */
40static int log_level = LOG_DEFAULT_LEVEL;
41
42
43void log_set_level(int level) {
44    log_level = level;
45}
46
47void log_init(void)
48{
49    static const char *name = "/dev/__kmsg__";
50    if (mknod(name, S_IFCHR | 0600, (1 << 8) | 11) == 0) {
51        log_fd = open(name, O_WRONLY);
52        fcntl(log_fd, F_SETFD, FD_CLOEXEC);
53        unlink(name);
54    }
55}
56
57#define LOG_BUF_MAX 512
58
59void log_write(int level, const char *fmt, ...)
60{
61    char buf[LOG_BUF_MAX];
62    va_list ap;
63
64    if (level > log_level) return;
65    if (log_fd < 0) return;
66
67    va_start(ap, fmt);
68    vsnprintf(buf, LOG_BUF_MAX, fmt, ap);
69    buf[LOG_BUF_MAX - 1] = 0;
70    va_end(ap);
71    write(log_fd, buf, strlen(buf));
72}
73
74/*
75 * android_name_to_id - returns the integer uid/gid associated with the given
76 * name, or -1U on error.
77 */
78static unsigned int android_name_to_id(const char *name)
79{
80    struct android_id_info *info = android_ids;
81    unsigned int n;
82
83    for (n = 0; n < android_id_count; n++) {
84        if (!strcmp(info[n].name, name))
85            return info[n].aid;
86    }
87
88    return -1U;
89}
90
91/*
92 * decode_uid - decodes and returns the given string, which can be either the
93 * numeric or name representation, into the integer uid or gid. Returns -1U on
94 * error.
95 */
96unsigned int decode_uid(const char *s)
97{
98    unsigned int v;
99
100    if (!s || *s == '\0')
101        return -1U;
102    if (isalpha(s[0]))
103        return android_name_to_id(s);
104
105    errno = 0;
106    v = (unsigned int) strtoul(s, 0, 0);
107    if (errno)
108        return -1U;
109    return v;
110}
111
112/*
113 * create_socket - creates a Unix domain socket in ANDROID_SOCKET_DIR
114 * ("/dev/socket") as dictated in init.rc. This socket is inherited by the
115 * daemon. We communicate the file descriptor's value via the environment
116 * variable ANDROID_SOCKET_ENV_PREFIX<name> ("ANDROID_SOCKET_foo").
117 */
118int create_socket(const char *name, int type, mode_t perm, uid_t uid, gid_t gid)
119{
120    struct sockaddr_un addr;
121    int fd, ret;
122
123    fd = socket(PF_UNIX, type, 0);
124    if (fd < 0) {
125        ERROR("Failed to open socket '%s': %s\n", name, strerror(errno));
126        return -1;
127    }
128
129    memset(&addr, 0 , sizeof(addr));
130    addr.sun_family = AF_UNIX;
131    snprintf(addr.sun_path, sizeof(addr.sun_path), ANDROID_SOCKET_DIR"/%s",
132             name);
133
134    ret = unlink(addr.sun_path);
135    if (ret != 0 && errno != ENOENT) {
136        ERROR("Failed to unlink old socket '%s': %s\n", name, strerror(errno));
137        goto out_close;
138    }
139
140    ret = bind(fd, (struct sockaddr *) &addr, sizeof (addr));
141    if (ret) {
142        ERROR("Failed to bind socket '%s': %s\n", name, strerror(errno));
143        goto out_unlink;
144    }
145
146    chown(addr.sun_path, uid, gid);
147    chmod(addr.sun_path, perm);
148
149    INFO("Created socket '%s' with mode '%o', user '%d', group '%d'\n",
150         addr.sun_path, perm, uid, gid);
151
152    return fd;
153
154out_unlink:
155    unlink(addr.sun_path);
156out_close:
157    close(fd);
158    return -1;
159}
160
161/* reads a file, making sure it is terminated with \n \0 */
162void *read_file(const char *fn, unsigned *_sz)
163{
164    char *data;
165    int sz;
166    int fd;
167
168    data = 0;
169    fd = open(fn, O_RDONLY);
170    if(fd < 0) return 0;
171
172    sz = lseek(fd, 0, SEEK_END);
173    if(sz < 0) goto oops;
174
175    if(lseek(fd, 0, SEEK_SET) != 0) goto oops;
176
177    data = (char*) malloc(sz + 2);
178    if(data == 0) goto oops;
179
180    if(read(fd, data, sz) != sz) goto oops;
181    close(fd);
182    data[sz] = '\n';
183    data[sz+1] = 0;
184    if(_sz) *_sz = sz;
185    return data;
186
187oops:
188    close(fd);
189    if(data != 0) free(data);
190    return 0;
191}
192
193void list_init(struct listnode *node)
194{
195    node->next = node;
196    node->prev = node;
197}
198
199void list_add_tail(struct listnode *head, struct listnode *item)
200{
201    item->next = head;
202    item->prev = head->prev;
203    head->prev->next = item;
204    head->prev = item;
205}
206
207void list_remove(struct listnode *item)
208{
209    item->next->prev = item->prev;
210    item->prev->next = item->next;
211}
212
213#define MAX_MTD_PARTITIONS 16
214
215static struct {
216    char name[16];
217    int number;
218} mtd_part_map[MAX_MTD_PARTITIONS];
219
220static int mtd_part_count = -1;
221
222static void find_mtd_partitions(void)
223{
224    int fd;
225    char buf[1024];
226    char *pmtdbufp;
227    ssize_t pmtdsize;
228    int r;
229
230    fd = open("/proc/mtd", O_RDONLY);
231    if (fd < 0)
232        return;
233
234    buf[sizeof(buf) - 1] = '\0';
235    pmtdsize = read(fd, buf, sizeof(buf) - 1);
236    pmtdbufp = buf;
237    while (pmtdsize > 0) {
238        int mtdnum, mtdsize, mtderasesize;
239        char mtdname[16];
240        mtdname[0] = '\0';
241        mtdnum = -1;
242        r = sscanf(pmtdbufp, "mtd%d: %x %x %15s",
243                   &mtdnum, &mtdsize, &mtderasesize, mtdname);
244        if ((r == 4) && (mtdname[0] == '"')) {
245            char *x = strchr(mtdname + 1, '"');
246            if (x) {
247                *x = 0;
248            }
249            INFO("mtd partition %d, %s\n", mtdnum, mtdname + 1);
250            if (mtd_part_count < MAX_MTD_PARTITIONS) {
251                strcpy(mtd_part_map[mtd_part_count].name, mtdname + 1);
252                mtd_part_map[mtd_part_count].number = mtdnum;
253                mtd_part_count++;
254            } else {
255                ERROR("too many mtd partitions\n");
256            }
257        }
258        while (pmtdsize > 0 && *pmtdbufp != '\n') {
259            pmtdbufp++;
260            pmtdsize--;
261        }
262        if (pmtdsize > 0) {
263            pmtdbufp++;
264            pmtdsize--;
265        }
266    }
267    close(fd);
268}
269
270int mtd_name_to_number(const char *name)
271{
272    int n;
273    if (mtd_part_count < 0) {
274        mtd_part_count = 0;
275        find_mtd_partitions();
276    }
277    for (n = 0; n < mtd_part_count; n++) {
278        if (!strcmp(name, mtd_part_map[n].name)) {
279            return mtd_part_map[n].number;
280        }
281    }
282    return -1;
283}
284
285/*
286 * gettime() - returns the time in seconds of the system's monotonic clock or
287 * zero on error.
288 */
289time_t gettime(void)
290{
291    struct timespec ts;
292    int ret;
293
294    ret = clock_gettime(CLOCK_MONOTONIC, &ts);
295    if (ret < 0) {
296        ERROR("clock_gettime(CLOCK_MONOTONIC) failed: %s\n", strerror(errno));
297        return 0;
298    }
299
300    return ts.tv_sec;
301}
302
303int mkdir_recursive(const char *pathname, mode_t mode)
304{
305    char buf[128];
306    const char *slash;
307    const char *p = pathname;
308    int width;
309    int ret;
310    struct stat info;
311
312    while ((slash = strchr(p, '/')) != NULL) {
313        width = slash - pathname;
314        p = slash + 1;
315        if (width < 0)
316            break;
317        if (width == 0)
318            continue;
319        if ((unsigned int)width > sizeof(buf) - 1) {
320            ERROR("path too long for mkdir_recursive\n");
321            return -1;
322        }
323        memcpy(buf, pathname, width);
324        buf[width] = 0;
325        if (stat(buf, &info) != 0) {
326            ret = mkdir(buf, mode);
327            if (ret && errno != EEXIST)
328                return ret;
329        }
330    }
331    ret = mkdir(pathname, mode);
332    if (ret && errno != EEXIST)
333        return ret;
334    return 0;
335}
336
337void sanitize(char *s)
338{
339    if (!s)
340        return;
341    while (isalnum(*s))
342        s++;
343    *s = 0;
344}
345void make_link(const char *oldpath, const char *newpath)
346{
347    int ret;
348    char buf[256];
349    char *slash;
350    int width;
351
352    slash = strrchr(newpath, '/');
353    if (!slash)
354        return;
355    width = slash - newpath;
356    if (width <= 0 || width > (int)sizeof(buf) - 1)
357        return;
358    memcpy(buf, newpath, width);
359    buf[width] = 0;
360    ret = mkdir_recursive(buf, 0755);
361    if (ret)
362        ERROR("Failed to create directory %s: %s (%d)\n", buf, strerror(errno), errno);
363
364    ret = symlink(oldpath, newpath);
365    if (ret && errno != EEXIST)
366        ERROR("Failed to symlink %s to %s: %s (%d)\n", oldpath, newpath, strerror(errno), errno);
367}
368
369void remove_link(const char *oldpath, const char *newpath)
370{
371    char path[256];
372    ssize_t ret;
373    ret = readlink(newpath, path, sizeof(path) - 1);
374    if (ret <= 0)
375        return;
376    path[ret] = 0;
377    if (!strcmp(path, oldpath))
378        unlink(newpath);
379}
380