devices.c revision 038862e152b98d0c0f355c6802beaa1ed59cefbe 
1/*
2 * Copyright (C) 2007 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 <errno.h>
18#include <stdio.h>
19#include <stdlib.h>
20#include <sys/stat.h>
21#include <sys/types.h>
22
23#include <fcntl.h>
24#include <dirent.h>
25#include <unistd.h>
26#include <string.h>
27
28#include <sys/socket.h>
29#include <sys/un.h>
30#include <linux/netlink.h>
31#include <private/android_filesystem_config.h>
32#include <sys/time.h>
33#include <asm/page.h>
34
35#include "init.h"
36#include "devices.h"
37
38#define CMDLINE_PREFIX  "/dev"
39#define SYSFS_PREFIX    "/sys"
40#define FIRMWARE_DIR    "/etc/firmware"
41#define MAX_QEMU_PERM 6
42
43struct uevent {
44    const char *action;
45    const char *path;
46    const char *subsystem;
47    const char *firmware;
48    int major;
49    int minor;
50};
51
52static int open_uevent_socket(void)
53{
54    struct sockaddr_nl addr;
55    int sz = 64*1024; // XXX larger? udev uses 16MB!
56    int s;
57
58    memset(&addr, 0, sizeof(addr));
59    addr.nl_family = AF_NETLINK;
60    addr.nl_pid = getpid();
61    addr.nl_groups = 0xffffffff;
62
63    s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
64    if(s < 0)
65        return -1;
66
67    setsockopt(s, SOL_SOCKET, SO_RCVBUFFORCE, &sz, sizeof(sz));
68
69    if(bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
70        close(s);
71        return -1;
72    }
73
74    return s;
75}
76
77struct perms_ {
78    char *name;
79    mode_t perm;
80    unsigned int uid;
81    unsigned int gid;
82    unsigned short prefix;
83};
84static struct perms_ devperms[] = {
85    { "/dev/null",          0666,   AID_ROOT,       AID_ROOT,       0 },
86    { "/dev/zero",          0666,   AID_ROOT,       AID_ROOT,       0 },
87    { "/dev/full",          0666,   AID_ROOT,       AID_ROOT,       0 },
88    { "/dev/ptmx",          0666,   AID_ROOT,       AID_ROOT,       0 },
89    { "/dev/tty",           0666,   AID_ROOT,       AID_ROOT,       0 },
90    { "/dev/random",        0666,   AID_ROOT,       AID_ROOT,       0 },
91    { "/dev/urandom",       0666,   AID_ROOT,       AID_ROOT,       0 },
92    { "/dev/ashmem",        0666,   AID_ROOT,       AID_ROOT,       0 },
93    { "/dev/binder",        0666,   AID_ROOT,       AID_ROOT,       0 },
94
95	    /* logger should be world writable (for logging) but not readable */
96    { "/dev/log/",          0662,   AID_ROOT,       AID_LOG,        1 },
97
98        /* these should not be world writable */
99    { "/dev/android_adb",   0660,   AID_ADB,        AID_ADB,        0 },
100    { "/dev/android_adb_enable",   0660,   AID_ADB,        AID_ADB,        0 },
101    /* TODO: remove legacy ttyMSM0 */
102    { "/dev/ttyMSM0",       0600,   AID_BLUETOOTH,  AID_BLUETOOTH,  0 },
103    { "/dev/ttyHS0",        0600,   AID_BLUETOOTH,  AID_BLUETOOTH,  0 },
104    { "/dev/uinput",        0600,   AID_BLUETOOTH,  AID_BLUETOOTH,  0 },
105    { "/dev/alarm",         0664,   AID_SYSTEM,     AID_RADIO,      0 },
106    { "/dev/tty0",          0660,   AID_ROOT,       AID_SYSTEM,     0 },
107    { "/dev/graphics/",     0660,   AID_ROOT,       AID_GRAPHICS,   1 },
108    { "/dev/hw3d",          0660,   AID_SYSTEM,     AID_GRAPHICS,   0 },
109    { "/dev/input/",        0660,   AID_ROOT,       AID_INPUT,      1 },
110    { "/dev/eac",           0660,   AID_ROOT,       AID_AUDIO,      0 },
111    { "/dev/cam",           0660,   AID_ROOT,       AID_CAMERA,     0 },
112    { "/dev/pmem",          0660,   AID_SYSTEM,     AID_GRAPHICS,   0 },
113    { "/dev/pmem_gpu",      0660,   AID_SYSTEM,     AID_GRAPHICS,   1 },
114    { "/dev/pmem_adsp",     0660,   AID_SYSTEM,     AID_AUDIO,      1 },
115    { "/dev/pmem_camera",   0660,   AID_SYSTEM,     AID_CAMERA,     1 },
116    { "/dev/oncrpc/",       0660,   AID_ROOT,       AID_SYSTEM,     1 },
117    { "/dev/adsp/",         0660,   AID_SYSTEM,     AID_AUDIO,      1 },
118    { "/dev/mt9t013",       0660,   AID_SYSTEM,     AID_SYSTEM,     0 },
119    { "/dev/akm8976_daemon",0640,   AID_COMPASS,    AID_SYSTEM,     0 },
120    { "/dev/akm8976_aot",   0640,   AID_COMPASS,    AID_SYSTEM,     0 },
121    { "/dev/akm8976_pffd",  0640,   AID_COMPASS,    AID_SYSTEM,     0 },
122    { "/dev/msm_pcm_out",   0660,   AID_SYSTEM,     AID_AUDIO,      1 },
123    { "/dev/msm_pcm_in",    0660,   AID_SYSTEM,     AID_AUDIO,      1 },
124    { "/dev/msm_pcm_ctl",   0660,   AID_SYSTEM,     AID_AUDIO,      1 },
125    { "/dev/msm_snd",       0660,   AID_SYSTEM,     AID_AUDIO,      1 },
126    { "/dev/msm_mp3",       0660,   AID_SYSTEM,     AID_AUDIO,      1 },
127    { "/dev/msm_snd",       0660,   AID_SYSTEM,     AID_AUDIO,      1 },
128    { "/dev/smd0",          0640,   AID_RADIO,      AID_RADIO,      0 },
129    { "/dev/qmi",           0640,   AID_RADIO,      AID_RADIO,      0 },
130    { "/dev/qmi0",          0640,   AID_RADIO,      AID_RADIO,      0 },
131    { "/dev/qmi1",          0640,   AID_RADIO,      AID_RADIO,      0 },
132    { "/dev/qmi2",          0640,   AID_RADIO,      AID_RADIO,      0 },
133    { "/dev/htc-acoustic",  0640,   AID_RADIO,      AID_RADIO,      0 },
134    { "/dev/snd/",          0664,   AID_SYSTEM,     AID_AUDIO,      1 },
135    { NULL, 0, 0, 0, 0 },
136};
137
138/* devperms_partners list and perm_node are for hardware specific /dev entries */
139struct perm_node {
140    struct perms_ dp;
141    struct listnode plist;
142};
143list_declare(devperms_partners);
144
145/*
146 * Permission override when in emulator mode, must be parsed before
147 * system properties is initalized.
148 */
149static int qemu_perm_count;
150static struct perms_ qemu_perms[MAX_QEMU_PERM + 1];
151
152int add_devperms_partners(const char *name, mode_t perm, unsigned int uid,
153                        unsigned int gid, unsigned short prefix) {
154    int size;
155    struct perm_node *node = malloc(sizeof (struct perm_node));
156    if (!node)
157        return -ENOMEM;
158
159    size = strlen(name) + 1;
160    if ((node->dp.name = malloc(size)) == NULL)
161        return -ENOMEM;
162
163    memcpy(node->dp.name, name, size);
164    node->dp.perm = perm;
165    node->dp.uid = uid;
166    node->dp.gid = gid;
167    node->dp.prefix = prefix;
168
169    list_add_tail(&devperms_partners, &node->plist);
170    return 0;
171}
172
173void qemu_init(void) {
174    qemu_perm_count = 0;
175    memset(&qemu_perms, 0, sizeof(qemu_perms));
176}
177
178static int qemu_perm(const char* name, mode_t perm, unsigned int uid,
179                         unsigned int gid, unsigned short prefix)
180{
181    char *buf;
182    if (qemu_perm_count == MAX_QEMU_PERM)
183        return -ENOSPC;
184
185    buf = malloc(strlen(name) + 1);
186    if (!buf)
187        return -errno;
188
189    strlcpy(buf, name, strlen(name) + 1);
190    qemu_perms[qemu_perm_count].name = buf;
191    qemu_perms[qemu_perm_count].perm = perm;
192    qemu_perms[qemu_perm_count].uid = uid;
193    qemu_perms[qemu_perm_count].gid = gid;
194    qemu_perms[qemu_perm_count].prefix = prefix;
195
196    qemu_perm_count++;
197    return 0;
198}
199
200/* Permission overrides for emulator that are parsed from /proc/cmdline. */
201void qemu_cmdline(const char* name, const char *value)
202{
203    char *buf;
204    if (!strcmp(name, "android.ril")) {
205        /* cmd line params currently assume /dev/ prefix */
206        if (asprintf(&buf, CMDLINE_PREFIX"/%s", value) == -1) {
207            return;
208        }
209        INFO("nani- buf:: %s\n", buf);
210        qemu_perm(buf, 0660, AID_RADIO, AID_ROOT, 0);
211    }
212}
213
214static int get_device_perm_inner(struct perms_ *perms, const char *path,
215                                    unsigned *uid, unsigned *gid, mode_t *perm)
216{
217    int i;
218    for(i = 0; perms[i].name; i++) {
219
220        if(perms[i].prefix) {
221            if(strncmp(path, perms[i].name, strlen(perms[i].name)))
222                continue;
223        } else {
224            if(strcmp(path, perms[i].name))
225                continue;
226        }
227        *uid = perms[i].uid;
228        *gid = perms[i].gid;
229        *perm = perms[i].perm;
230        return 0;
231    }
232    return -1;
233}
234
235/* First checks for emulator specific permissions specified in /proc/cmdline. */
236static mode_t get_device_perm(const char *path, unsigned *uid, unsigned *gid)
237{
238    mode_t perm;
239
240    if (get_device_perm_inner(qemu_perms, path, uid, gid, &perm) == 0) {
241        return perm;
242    } else if (get_device_perm_inner(devperms, path, uid, gid, &perm) == 0) {
243        return perm;
244    } else {
245        struct listnode *node;
246        struct perm_node *perm_node;
247        struct perms_ *dp;
248
249        /* Check partners list. */
250        list_for_each(node, &devperms_partners) {
251            perm_node = node_to_item(node, struct perm_node, plist);
252            dp = &perm_node->dp;
253
254            if (dp->prefix) {
255                if (strncmp(path, dp->name, strlen(dp->name)))
256                    continue;
257            } else {
258                if (strcmp(path, dp->name))
259                    continue;
260            }
261            /* Found perm in partner list. */
262            *uid = dp->uid;
263            *gid = dp->gid;
264            return dp->perm;
265        }
266        /* Default if nothing found. */
267        *uid = 0;
268        *gid = 0;
269        return 0600;
270    }
271}
272
273static void make_device(const char *path, int block, int major, int minor)
274{
275    unsigned uid;
276    unsigned gid;
277    mode_t mode;
278    dev_t dev;
279
280    if(major > 255 || minor > 255)
281        return;
282
283    mode = get_device_perm(path, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
284    dev = (major << 8) | minor;
285    mknod(path, mode, dev);
286    chown(path, uid, gid);
287}
288
289#ifdef LOG_UEVENTS
290
291static inline suseconds_t get_usecs(void)
292{
293    struct timeval tv;
294    gettimeofday(&tv, 0);
295    return tv.tv_sec * (suseconds_t) 1000000 + tv.tv_usec;
296}
297
298#define log_event_print(x...) INFO(x)
299
300#else
301
302#define log_event_print(fmt, args...)   do { } while (0)
303#define get_usecs()                     0
304
305#endif
306
307static void parse_event(const char *msg, struct uevent *uevent)
308{
309    uevent->action = "";
310    uevent->path = "";
311    uevent->subsystem = "";
312    uevent->firmware = "";
313    uevent->major = -1;
314    uevent->minor = -1;
315
316        /* currently ignoring SEQNUM */
317    while(*msg) {
318        if(!strncmp(msg, "ACTION=", 7)) {
319            msg += 7;
320            uevent->action = msg;
321        } else if(!strncmp(msg, "DEVPATH=", 8)) {
322            msg += 8;
323            uevent->path = msg;
324        } else if(!strncmp(msg, "SUBSYSTEM=", 10)) {
325            msg += 10;
326            uevent->subsystem = msg;
327        } else if(!strncmp(msg, "FIRMWARE=", 9)) {
328            msg += 9;
329            uevent->firmware = msg;
330        } else if(!strncmp(msg, "MAJOR=", 6)) {
331            msg += 6;
332            uevent->major = atoi(msg);
333        } else if(!strncmp(msg, "MINOR=", 6)) {
334            msg += 6;
335            uevent->minor = atoi(msg);
336        }
337
338            /* advance to after the next \0 */
339        while(*msg++)
340            ;
341    }
342
343    log_event_print("event { '%s', '%s', '%s', '%s', %d, %d }\n",
344                    uevent->action, uevent->path, uevent->subsystem,
345                    uevent->firmware, uevent->major, uevent->minor);
346}
347
348static void handle_device_event(struct uevent *uevent)
349{
350    char devpath[96];
351    char *base, *name;
352    int block;
353
354        /* if it's not a /dev device, nothing to do */
355    if((uevent->major < 0) || (uevent->minor < 0))
356        return;
357
358        /* do we have a name? */
359    name = strrchr(uevent->path, '/');
360    if(!name)
361        return;
362    name++;
363
364        /* too-long names would overrun our buffer */
365    if(strlen(name) > 64)
366        return;
367
368        /* are we block or char? where should we live? */
369    if(!strncmp(uevent->subsystem, "block", 5)) {
370        block = 1;
371        base = "/dev/block/";
372        mkdir(base, 0755);
373    } else {
374        block = 0;
375            /* this should probably be configurable somehow */
376        if(!strncmp(uevent->subsystem, "graphics", 8)) {
377            base = "/dev/graphics/";
378            mkdir(base, 0755);
379        } else if (!strncmp(uevent->subsystem, "oncrpc", 6)) {
380            base = "/dev/oncrpc/";
381            mkdir(base, 0755);
382        } else if (!strncmp(uevent->subsystem, "adsp", 4)) {
383            base = "/dev/adsp/";
384            mkdir(base, 0755);
385      } else if(!strncmp(uevent->subsystem, "input", 5)) {
386            base = "/dev/input/";
387            mkdir(base, 0755);
388        } else if(!strncmp(uevent->subsystem, "mtd", 3)) {
389            base = "/dev/mtd/";
390            mkdir(base, 0755);
391        } else if(!strncmp(uevent->subsystem, "sound", 5)) {
392            base = "/dev/snd/";
393            mkdir(base, 0755);
394        } else if(!strncmp(uevent->subsystem, "misc", 4) &&
395                    !strncmp(name, "log_", 4)) {
396            base = "/dev/log/";
397            mkdir(base, 0755);
398            name += 4;
399        } else
400            base = "/dev/";
401    }
402
403    snprintf(devpath, sizeof(devpath), "%s%s", base, name);
404
405    if(!strcmp(uevent->action, "add")) {
406        make_device(devpath, block, uevent->major, uevent->minor);
407        return;
408    }
409
410    if(!strcmp(uevent->action, "remove")) {
411        unlink(devpath);
412        return;
413    }
414}
415
416static int load_firmware(int fw_fd, int loading_fd, int data_fd)
417{
418    struct stat st;
419    long len_to_copy;
420    int ret = 0;
421
422    if(fstat(fw_fd, &st) < 0)
423        return -1;
424    len_to_copy = st.st_size;
425
426    write(loading_fd, "1", 1);  /* start transfer */
427
428    while (len_to_copy > 0) {
429        char buf[PAGE_SIZE];
430        ssize_t nr;
431
432        nr = read(fw_fd, buf, sizeof(buf));
433        if(!nr)
434            break;
435        if(nr < 0) {
436            ret = -1;
437            break;
438        }
439
440        len_to_copy -= nr;
441        while (nr > 0) {
442            ssize_t nw = 0;
443
444            nw = write(data_fd, buf + nw, nr);
445            if(nw <= 0) {
446                ret = -1;
447                goto out;
448            }
449            nr -= nw;
450        }
451    }
452
453out:
454    if(!ret)
455        write(loading_fd, "0", 1);  /* successful end of transfer */
456    else
457        write(loading_fd, "-1", 2); /* abort transfer */
458
459    return ret;
460}
461
462static void process_firmware_event(struct uevent *uevent)
463{
464    char *root, *loading, *data, *file;
465    int l, loading_fd, data_fd, fw_fd;
466
467    log_event_print("firmware event { '%s', '%s' }\n",
468                    uevent->path, uevent->firmware);
469
470    l = asprintf(&root, SYSFS_PREFIX"%s/", uevent->path);
471    if (l == -1)
472        return;
473
474    l = asprintf(&loading, "%sloading", root);
475    if (l == -1)
476        goto root_free_out;
477
478    l = asprintf(&data, "%sdata", root);
479    if (l == -1)
480        goto loading_free_out;
481
482    l = asprintf(&file, FIRMWARE_DIR"/%s", uevent->firmware);
483    if (l == -1)
484        goto data_free_out;
485
486    loading_fd = open(loading, O_WRONLY);
487    if(loading_fd < 0)
488        goto file_free_out;
489
490    data_fd = open(data, O_WRONLY);
491    if(data_fd < 0)
492        goto loading_close_out;
493
494    fw_fd = open(file, O_RDONLY);
495    if(fw_fd < 0)
496        goto data_close_out;
497
498    if(!load_firmware(fw_fd, loading_fd, data_fd))
499        log_event_print("firmware copy success { '%s', '%s' }\n", root, file);
500    else
501        log_event_print("firmware copy failure { '%s', '%s' }\n", root, file);
502
503    close(fw_fd);
504data_close_out:
505    close(data_fd);
506loading_close_out:
507    close(loading_fd);
508file_free_out:
509    free(file);
510data_free_out:
511    free(data);
512loading_free_out:
513    free(loading);
514root_free_out:
515    free(root);
516}
517
518static void handle_firmware_event(struct uevent *uevent)
519{
520    pid_t pid;
521
522    if(strcmp(uevent->subsystem, "firmware"))
523        return;
524
525    if(strcmp(uevent->action, "add"))
526        return;
527
528    /* we fork, to avoid making large memory allocations in init proper */
529    pid = fork();
530    if (!pid) {
531        process_firmware_event(uevent);
532        exit(EXIT_SUCCESS);
533    }
534}
535
536#define UEVENT_MSG_LEN  1024
537void handle_device_fd(int fd)
538{
539    char msg[UEVENT_MSG_LEN+2];
540    int n;
541
542    while((n = recv(fd, msg, UEVENT_MSG_LEN, 0)) > 0) {
543        struct uevent uevent;
544
545        if(n == UEVENT_MSG_LEN)   /* overflow -- discard */
546            continue;
547
548        msg[n] = '\0';
549        msg[n+1] = '\0';
550
551        parse_event(msg, &uevent);
552
553        handle_device_event(&uevent);
554        handle_firmware_event(&uevent);
555    }
556}
557
558/* Coldboot walks parts of the /sys tree and pokes the uevent files
559** to cause the kernel to regenerate device add events that happened
560** before init's device manager was started
561**
562** We drain any pending events from the netlink socket every time
563** we poke another uevent file to make sure we don't overrun the
564** socket's buffer.
565*/
566
567static void do_coldboot(int event_fd, DIR *d)
568{
569    struct dirent *de;
570    int dfd, fd;
571
572    dfd = dirfd(d);
573
574    fd = openat(dfd, "uevent", O_WRONLY);
575    if(fd >= 0) {
576        write(fd, "add\n", 4);
577        close(fd);
578        handle_device_fd(event_fd);
579    }
580
581    while((de = readdir(d))) {
582        DIR *d2;
583
584        if(de->d_type != DT_DIR || de->d_name[0] == '.')
585            continue;
586
587        fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
588        if(fd < 0)
589            continue;
590
591        d2 = fdopendir(fd);
592        if(d2 == 0)
593            close(fd);
594        else {
595            do_coldboot(event_fd, d2);
596            closedir(d2);
597        }
598    }
599}
600
601static void coldboot(int event_fd, const char *path)
602{
603    DIR *d = opendir(path);
604    if(d) {
605        do_coldboot(event_fd, d);
606        closedir(d);
607    }
608}
609
610int device_init(void)
611{
612    suseconds_t t0, t1;
613    int fd;
614
615    fd = open_uevent_socket();
616    if(fd < 0)
617        return -1;
618
619    fcntl(fd, F_SETFD, FD_CLOEXEC);
620    fcntl(fd, F_SETFL, O_NONBLOCK);
621
622    t0 = get_usecs();
623    coldboot(fd, "/sys/class");
624    coldboot(fd, "/sys/block");
625    coldboot(fd, "/sys/devices");
626    t1 = get_usecs();
627
628    log_event_print("coldboot %ld uS\n", ((long) (t1 - t0)));
629
630    return fd;
631}
632