devices.c revision 5bb44c8ea2bc513fefc526918980ab3d17494ecc 
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    { "/dev/ttyMSM0",       0660,   AID_BLUETOOTH,  AID_BLUETOOTH,  0 },
102    { "/dev/alarm",         0664,   AID_SYSTEM,     AID_RADIO,      0 },
103    { "/dev/tty0",          0666,   AID_ROOT,       AID_SYSTEM,     0 },
104    { "/dev/graphics/",     0660,   AID_ROOT,       AID_GRAPHICS,   1 },
105    { "/dev/hw3d",          0660,   AID_SYSTEM,     AID_GRAPHICS,   0 },
106    { "/dev/input/",        0660,   AID_ROOT,       AID_INPUT,      1 },
107    { "/dev/eac",           0660,   AID_ROOT,       AID_AUDIO,      0 },
108    { "/dev/cam",           0660,   AID_ROOT,       AID_CAMERA,     0 },
109    { "/dev/pmem",          0660,   AID_SYSTEM,     AID_GRAPHICS,   0 },
110    { "/dev/pmem_gpu",      0660,   AID_SYSTEM,     AID_GRAPHICS,   1 },
111    { "/dev/pmem_adsp",     0660,   AID_SYSTEM,     AID_AUDIO,      1 },
112    { "/dev/pmem_camera",   0660,   AID_SYSTEM,     AID_CAMERA,     1 },
113    { "/dev/oncrpc/",       0660,   AID_ROOT,       AID_SYSTEM,     1 },
114    { "/dev/adsp/",         0660,   AID_SYSTEM,     AID_AUDIO,      1 },
115    { "/dev/mt9t013",       0660,   AID_SYSTEM,     AID_SYSTEM,     0 },
116    { "/dev/akm8976_daemon",0640,   AID_COMPASS,    AID_SYSTEM,     0 },
117    { "/dev/akm8976_aot",   0640,   AID_COMPASS,    AID_SYSTEM,     0 },
118    { "/dev/akm8976_pffd",  0640,   AID_COMPASS,    AID_SYSTEM,     0 },
119    { "/dev/msm_pcm_out",   0660,   AID_SYSTEM,     AID_AUDIO,      1 },
120    { "/dev/msm_pcm_in",    0660,   AID_SYSTEM,     AID_AUDIO,      1 },
121    { "/dev/msm_pcm_ctl",   0660,   AID_SYSTEM,     AID_AUDIO,      1 },
122    { "/dev/msm_mp3",       0660,   AID_SYSTEM,     AID_AUDIO,      1 },
123    { "/dev/msm_snd",       0660,   AID_SYSTEM,     AID_AUDIO,      1 },
124    { "/dev/smd0",          0640,   AID_RADIO,      AID_RADIO,      0 },
125    { "/dev/qmi",           0640,   AID_RADIO,      AID_RADIO,      0 },
126    { "/dev/qmi0",          0640,   AID_RADIO,      AID_RADIO,      0 },
127    { "/dev/qmi1",          0640,   AID_RADIO,      AID_RADIO,      0 },
128    { "/dev/qmi2",          0640,   AID_RADIO,      AID_RADIO,      0 },
129    { "/dev/htc-acoustic",  0640,   AID_RADIO,      AID_RADIO,      0 },
130    { "/dev/snd/",          0664,   AID_SYSTEM,     AID_AUDIO,      1 },
131    { NULL, 0, 0, 0, 0 },
132};
133
134/* devperms_partners list and perm_node are for hardware specific /dev entries */
135struct perm_node {
136    struct perms_ dp;
137    struct listnode plist;
138};
139list_declare(devperms_partners);
140
141/*
142 * Permission override when in emulator mode, must be parsed before
143 * system properties is initalized.
144 */
145static int qemu_perm_count;
146static struct perms_ qemu_perms[MAX_QEMU_PERM + 1];
147
148int add_devperms_partners(const char *name, mode_t perm, unsigned int uid,
149                        unsigned int gid, unsigned short prefix) {
150    int size;
151    struct perm_node *node = malloc(sizeof (struct perm_node));
152    if (!node)
153        return -ENOMEM;
154
155    size = strlen(name) + 1;
156    if ((node->dp.name = malloc(size)) == NULL)
157        return -ENOMEM;
158
159    memcpy(node->dp.name, name, size);
160    node->dp.perm = perm;
161    node->dp.uid = uid;
162    node->dp.gid = gid;
163    node->dp.prefix = prefix;
164
165    list_add_tail(&devperms_partners, &node->plist);
166    return 0;
167}
168
169void qemu_init(void) {
170    qemu_perm_count = 0;
171    memset(&qemu_perms, 0, sizeof(qemu_perms));
172}
173
174static int qemu_perm(const char* name, mode_t perm, unsigned int uid,
175                         unsigned int gid, unsigned short prefix)
176{
177    char *buf;
178    if (qemu_perm_count == MAX_QEMU_PERM)
179        return -ENOSPC;
180
181    buf = malloc(strlen(name) + 1);
182    if (!buf)
183        return -errno;
184
185    strlcpy(buf, name, strlen(name) + 1);
186    qemu_perms[qemu_perm_count].name = buf;
187    qemu_perms[qemu_perm_count].perm = perm;
188    qemu_perms[qemu_perm_count].uid = uid;
189    qemu_perms[qemu_perm_count].gid = gid;
190    qemu_perms[qemu_perm_count].prefix = prefix;
191
192    qemu_perm_count++;
193    return 0;
194}
195
196/* Permission overrides for emulator that are parsed from /proc/cmdline. */
197void qemu_cmdline(const char* name, const char *value)
198{
199    char *buf;
200    if (!strcmp(name, "android.ril")) {
201        /* cmd line params currently assume /dev/ prefix */
202        if (asprintf(&buf, CMDLINE_PREFIX"/%s", value) == -1) {
203            return;
204        }
205        INFO("nani- buf:: %s\n", buf);
206        qemu_perm(buf, 0660, AID_RADIO, AID_ROOT, 0);
207    }
208}
209
210static int get_device_perm_inner(struct perms_ *perms, const char *path,
211                                    unsigned *uid, unsigned *gid, mode_t *perm)
212{
213    int i;
214    for(i = 0; perms[i].name; i++) {
215
216        if(perms[i].prefix) {
217            if(strncmp(path, perms[i].name, strlen(perms[i].name)))
218                continue;
219        } else {
220            if(strcmp(path, perms[i].name))
221                continue;
222        }
223        *uid = perms[i].uid;
224        *gid = perms[i].gid;
225        *perm = perms[i].perm;
226        return 0;
227    }
228    return -1;
229}
230
231/* First checks for emulator specific permissions specified in /proc/cmdline. */
232static mode_t get_device_perm(const char *path, unsigned *uid, unsigned *gid)
233{
234    mode_t perm;
235
236    if (get_device_perm_inner(qemu_perms, path, uid, gid, &perm) == 0) {
237        return perm;
238    } else if (get_device_perm_inner(devperms, path, uid, gid, &perm) == 0) {
239        return perm;
240    } else {
241        struct listnode *node;
242        struct perm_node *perm_node;
243        struct perms_ *dp;
244
245        /* Check partners list. */
246        list_for_each(node, &devperms_partners) {
247            perm_node = node_to_item(node, struct perm_node, plist);
248            dp = &perm_node->dp;
249
250            if (dp->prefix) {
251                if (strncmp(path, dp->name, strlen(dp->name)))
252                    continue;
253            } else {
254                if (strcmp(path, dp->name))
255                    continue;
256            }
257            /* Found perm in partner list. */
258            *uid = dp->uid;
259            *gid = dp->gid;
260            return dp->perm;
261        }
262        /* Default if nothing found. */
263        *uid = 0;
264        *gid = 0;
265        return 0600;
266    }
267}
268
269static void make_device(const char *path, int block, int major, int minor)
270{
271    unsigned uid;
272    unsigned gid;
273    mode_t mode;
274    dev_t dev;
275
276    if(major > 255 || minor > 255)
277        return;
278
279    mode = get_device_perm(path, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
280    dev = (major << 8) | minor;
281    mknod(path, mode, dev);
282    chown(path, uid, gid);
283}
284
285#ifdef LOG_UEVENTS
286
287static inline suseconds_t get_usecs(void)
288{
289    struct timeval tv;
290    gettimeofday(&tv, 0);
291    return tv.tv_sec * (suseconds_t) 1000000 + tv.tv_usec;
292}
293
294#define log_event_print(x...) INFO(x)
295
296#else
297
298#define log_event_print(fmt, args...)   do { } while (0)
299#define get_usecs()                     0
300
301#endif
302
303static void parse_event(const char *msg, struct uevent *uevent)
304{
305    uevent->action = "";
306    uevent->path = "";
307    uevent->subsystem = "";
308    uevent->firmware = "";
309    uevent->major = -1;
310    uevent->minor = -1;
311
312        /* currently ignoring SEQNUM */
313    while(*msg) {
314        if(!strncmp(msg, "ACTION=", 7)) {
315            msg += 7;
316            uevent->action = msg;
317        } else if(!strncmp(msg, "DEVPATH=", 8)) {
318            msg += 8;
319            uevent->path = msg;
320        } else if(!strncmp(msg, "SUBSYSTEM=", 10)) {
321            msg += 10;
322            uevent->subsystem = msg;
323        } else if(!strncmp(msg, "FIRMWARE=", 9)) {
324            msg += 9;
325            uevent->firmware = msg;
326        } else if(!strncmp(msg, "MAJOR=", 6)) {
327            msg += 6;
328            uevent->major = atoi(msg);
329        } else if(!strncmp(msg, "MINOR=", 6)) {
330            msg += 6;
331            uevent->minor = atoi(msg);
332        }
333
334            /* advance to after the next \0 */
335        while(*msg++)
336            ;
337    }
338
339    log_event_print("event { '%s', '%s', '%s', '%s', %d, %d }\n",
340                    uevent->action, uevent->path, uevent->subsystem,
341                    uevent->firmware, uevent->major, uevent->minor);
342}
343
344static void handle_device_event(struct uevent *uevent)
345{
346    char devpath[96];
347    char *base, *name;
348    int block;
349
350        /* if it's not a /dev device, nothing to do */
351    if((uevent->major < 0) || (uevent->minor < 0))
352        return;
353
354        /* do we have a name? */
355    name = strrchr(uevent->path, '/');
356    if(!name)
357        return;
358    name++;
359
360        /* too-long names would overrun our buffer */
361    if(strlen(name) > 64)
362        return;
363
364        /* are we block or char? where should we live? */
365    if(!strncmp(uevent->path, "/block", 6)) {
366        block = 1;
367        base = "/dev/block/";
368        mkdir(base, 0755);
369    } else {
370        block = 0;
371            /* this should probably be configurable somehow */
372        if(!strncmp(uevent->path, "/class/graphics/", 16)) {
373            base = "/dev/graphics/";
374            mkdir(base, 0755);
375        } else if (!strncmp(uevent->path, "/class/oncrpc/", 14)) {
376            base = "/dev/oncrpc/";
377            mkdir(base, 0755);
378        } else if (!strncmp(uevent->path, "/class/adsp/", 12)) {
379            base = "/dev/adsp/";
380            mkdir(base, 0755);
381      } else if(!strncmp(uevent->path, "/class/input/", 13)) {
382            base = "/dev/input/";
383            mkdir(base, 0755);
384        } else if(!strncmp(uevent->path, "/class/mtd/", 11)) {
385            base = "/dev/mtd/";
386            mkdir(base, 0755);
387        } else if(!strncmp(uevent->subsystem, "sound", 5)) {
388            base = "/dev/snd/";
389            mkdir(base, 0755);
390        } else if(!strncmp(uevent->path, "/class/misc/", 12) &&
391                    !strncmp(name, "log_", 4)) {
392            base = "/dev/log/";
393            mkdir(base, 0755);
394            name += 4;
395        } else
396            base = "/dev/";
397    }
398
399    snprintf(devpath, sizeof(devpath), "%s%s", base, name);
400
401    if(!strcmp(uevent->action, "add")) {
402        make_device(devpath, block, uevent->major, uevent->minor);
403        return;
404    }
405
406    if(!strcmp(uevent->action, "remove")) {
407        unlink(devpath);
408        return;
409    }
410}
411
412static int load_firmware(int fw_fd, int loading_fd, int data_fd)
413{
414    struct stat st;
415    long len_to_copy;
416    int ret = 0;
417
418    if(fstat(fw_fd, &st) < 0)
419        return -1;
420    len_to_copy = st.st_size;
421
422    write(loading_fd, "1", 1);  /* start transfer */
423
424    while (len_to_copy > 0) {
425        char buf[PAGE_SIZE];
426        ssize_t nr;
427
428        nr = read(fw_fd, buf, sizeof(buf));
429        if(!nr)
430            break;
431        if(nr < 0) {
432            ret = -1;
433            break;
434        }
435
436        len_to_copy -= nr;
437        while (nr > 0) {
438            ssize_t nw = 0;
439
440            nw = write(data_fd, buf + nw, nr);
441            if(nw <= 0) {
442                ret = -1;
443                goto out;
444            }
445            nr -= nw;
446        }
447    }
448
449out:
450    if(!ret)
451        write(loading_fd, "0", 1);  /* successful end of transfer */
452    else
453        write(loading_fd, "-1", 2); /* abort transfer */
454
455    return ret;
456}
457
458static void process_firmware_event(struct uevent *uevent)
459{
460    char *root, *loading, *data, *file;
461    int l, loading_fd, data_fd, fw_fd;
462
463    log_event_print("firmware event { '%s', '%s' }\n",
464                    uevent->path, uevent->firmware);
465
466    l = asprintf(&root, SYSFS_PREFIX"%s/", uevent->path);
467    if (l == -1)
468        return;
469
470    l = asprintf(&loading, "%sloading", root);
471    if (l == -1)
472        goto root_free_out;
473
474    l = asprintf(&data, "%sdata", root);
475    if (l == -1)
476        goto loading_free_out;
477
478    l = asprintf(&file, FIRMWARE_DIR"/%s", uevent->firmware);
479    if (l == -1)
480        goto data_free_out;
481
482    loading_fd = open(loading, O_WRONLY);
483    if(loading_fd < 0)
484        goto file_free_out;
485
486    data_fd = open(data, O_WRONLY);
487    if(data_fd < 0)
488        goto loading_close_out;
489
490    fw_fd = open(file, O_RDONLY);
491    if(fw_fd < 0)
492        goto data_close_out;
493
494    if(!load_firmware(fw_fd, loading_fd, data_fd))
495        log_event_print("firmware copy success { '%s', '%s' }\n", root, file);
496    else
497        log_event_print("firmware copy failure { '%s', '%s' }\n", root, file);
498
499    close(fw_fd);
500data_close_out:
501    close(data_fd);
502loading_close_out:
503    close(loading_fd);
504file_free_out:
505    free(file);
506data_free_out:
507    free(data);
508loading_free_out:
509    free(loading);
510root_free_out:
511    free(root);
512}
513
514static void handle_firmware_event(struct uevent *uevent)
515{
516    pid_t pid;
517
518    if(strcmp(uevent->subsystem, "firmware"))
519        return;
520
521    if(strcmp(uevent->action, "add"))
522        return;
523
524    /* we fork, to avoid making large memory allocations in init proper */
525    pid = fork();
526    if (!pid) {
527        process_firmware_event(uevent);
528        exit(EXIT_SUCCESS);
529    }
530}
531
532#define UEVENT_MSG_LEN  1024
533void handle_device_fd(int fd)
534{
535    char msg[UEVENT_MSG_LEN+2];
536    int n;
537
538    while((n = recv(fd, msg, UEVENT_MSG_LEN, 0)) > 0) {
539        struct uevent uevent;
540
541        if(n == UEVENT_MSG_LEN)   /* overflow -- discard */
542            continue;
543
544        msg[n] = '\0';
545        msg[n+1] = '\0';
546
547        parse_event(msg, &uevent);
548
549        handle_device_event(&uevent);
550        handle_firmware_event(&uevent);
551    }
552}
553
554/* Coldboot walks parts of the /sys tree and pokes the uevent files
555** to cause the kernel to regenerate device add events that happened
556** before init's device manager was started
557**
558** We drain any pending events from the netlink socket every time
559** we poke another uevent file to make sure we don't overrun the
560** socket's buffer.
561*/
562
563static void do_coldboot(int event_fd, DIR *d)
564{
565    struct dirent *de;
566    int dfd, fd;
567
568    dfd = dirfd(d);
569
570    fd = openat(dfd, "uevent", O_WRONLY);
571    if(fd >= 0) {
572        write(fd, "add\n", 4);
573        close(fd);
574        handle_device_fd(event_fd);
575    }
576
577    while((de = readdir(d))) {
578        DIR *d2;
579
580        if(de->d_type != DT_DIR || de->d_name[0] == '.')
581            continue;
582
583        fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
584        if(fd < 0)
585            continue;
586
587        d2 = fdopendir(fd);
588        if(d2 == 0)
589            close(fd);
590        else {
591            do_coldboot(event_fd, d2);
592            closedir(d2);
593        }
594    }
595}
596
597static void coldboot(int event_fd, const char *path)
598{
599    DIR *d = opendir(path);
600    if(d) {
601        do_coldboot(event_fd, d);
602        closedir(d);
603    }
604}
605
606int device_init(void)
607{
608    suseconds_t t0, t1;
609    int fd;
610
611    fd = open_uevent_socket();
612    if(fd < 0)
613        return -1;
614
615    fcntl(fd, F_SETFD, FD_CLOEXEC);
616    fcntl(fd, F_SETFL, O_NONBLOCK);
617
618    t0 = get_usecs();
619    coldboot(fd, "/sys/class");
620    coldboot(fd, "/sys/block");
621    coldboot(fd, "/sys/devices");
622    t1 = get_usecs();
623
624    log_event_print("coldboot %ld uS\n", ((long) (t1 - t0)));
625
626    return fd;
627}
628