devices.c revision 35237d135807af84bf9b0e5b8d7f8633e58db6f5 
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_mp3",       0660,   AID_SYSTEM,     AID_AUDIO,      1 },
126    { "/dev/smd0",          0640,   AID_RADIO,      AID_RADIO,      0 },
127    { "/dev/qmi",           0640,   AID_RADIO,      AID_RADIO,      0 },
128    { "/dev/qmi0",          0640,   AID_RADIO,      AID_RADIO,      0 },
129    { "/dev/qmi1",          0640,   AID_RADIO,      AID_RADIO,      0 },
130    { "/dev/qmi2",          0640,   AID_RADIO,      AID_RADIO,      0 },
131    { "/dev/htc-acoustic",  0640,   AID_RADIO,      AID_RADIO,      0 },
132    { NULL, 0, 0, 0, 0 },
133};
134
135/* devperms_partners list and perm_node are for hardware specific /dev entries */
136struct perm_node {
137    struct perms_ dp;
138    struct listnode plist;
139};
140list_declare(devperms_partners);
141
142/*
143 * Permission override when in emulator mode, must be parsed before
144 * system properties is initalized.
145 */
146static int qemu_perm_count;
147static struct perms_ qemu_perms[MAX_QEMU_PERM + 1];
148
149int add_devperms_partners(const char *name, mode_t perm, unsigned int uid,
150                        unsigned int gid, unsigned short prefix) {
151    int size;
152    struct perm_node *node = malloc(sizeof (struct perm_node));
153    if (!node)
154        return -ENOMEM;
155
156    size = strlen(name) + 1;
157    if ((node->dp.name = malloc(size)) == NULL)
158        return -ENOMEM;
159
160    memcpy(node->dp.name, name, size);
161    node->dp.perm = perm;
162    node->dp.uid = uid;
163    node->dp.gid = gid;
164    node->dp.prefix = prefix;
165
166    list_add_tail(&devperms_partners, &node->plist);
167    return 0;
168}
169
170void qemu_init(void) {
171    qemu_perm_count = 0;
172    memset(&qemu_perms, 0, sizeof(qemu_perms));
173}
174
175static int qemu_perm(const char* name, mode_t perm, unsigned int uid,
176                         unsigned int gid, unsigned short prefix)
177{
178    char *buf;
179    if (qemu_perm_count == MAX_QEMU_PERM)
180        return -ENOSPC;
181
182    buf = malloc(strlen(name) + 1);
183    if (!buf)
184        return -errno;
185
186    strlcpy(buf, name, strlen(name) + 1);
187    qemu_perms[qemu_perm_count].name = buf;
188    qemu_perms[qemu_perm_count].perm = perm;
189    qemu_perms[qemu_perm_count].uid = uid;
190    qemu_perms[qemu_perm_count].gid = gid;
191    qemu_perms[qemu_perm_count].prefix = prefix;
192
193    qemu_perm_count++;
194    return 0;
195}
196
197/* Permission overrides for emulator that are parsed from /proc/cmdline. */
198void qemu_cmdline(const char* name, const char *value)
199{
200    char *buf;
201    if (!strcmp(name, "android.ril")) {
202        /* cmd line params currently assume /dev/ prefix */
203        if (asprintf(&buf, CMDLINE_PREFIX"/%s", value) == -1) {
204            return;
205        }
206        INFO("nani- buf:: %s\n", buf);
207        qemu_perm(buf, 0660, AID_RADIO, AID_ROOT, 0);
208    }
209}
210
211static int get_device_perm_inner(struct perms_ *perms, const char *path,
212                                    unsigned *uid, unsigned *gid, mode_t *perm)
213{
214    int i;
215    for(i = 0; perms[i].name; i++) {
216
217        if(perms[i].prefix) {
218            if(strncmp(path, perms[i].name, strlen(perms[i].name)))
219                continue;
220        } else {
221            if(strcmp(path, perms[i].name))
222                continue;
223        }
224        *uid = perms[i].uid;
225        *gid = perms[i].gid;
226        *perm = perms[i].perm;
227        return 0;
228    }
229    return -1;
230}
231
232/* First checks for emulator specific permissions specified in /proc/cmdline. */
233static mode_t get_device_perm(const char *path, unsigned *uid, unsigned *gid)
234{
235    mode_t perm;
236
237    if (get_device_perm_inner(qemu_perms, path, uid, gid, &perm) == 0) {
238        return perm;
239    } else if (get_device_perm_inner(devperms, path, uid, gid, &perm) == 0) {
240        return perm;
241    } else {
242        struct listnode *node;
243        struct perm_node *perm_node;
244        struct perms_ *dp;
245
246        /* Check partners list. */
247        list_for_each(node, &devperms_partners) {
248            perm_node = node_to_item(node, struct perm_node, plist);
249            dp = &perm_node->dp;
250
251            if (dp->prefix) {
252                if (strncmp(path, dp->name, strlen(dp->name)))
253                    continue;
254            } else {
255                if (strcmp(path, dp->name))
256                    continue;
257            }
258            /* Found perm in partner list. */
259            *uid = dp->uid;
260            *gid = dp->gid;
261            return dp->perm;
262        }
263        /* Default if nothing found. */
264        *uid = 0;
265        *gid = 0;
266        return 0600;
267    }
268}
269
270static void make_device(const char *path, int block, int major, int minor)
271{
272    unsigned uid;
273    unsigned gid;
274    mode_t mode;
275    dev_t dev;
276
277    if(major > 255 || minor > 255)
278        return;
279
280    mode = get_device_perm(path, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
281    dev = (major << 8) | minor;
282    mknod(path, mode, dev);
283    chown(path, uid, gid);
284}
285
286#ifdef LOG_UEVENTS
287
288static inline suseconds_t get_usecs(void)
289{
290    struct timeval tv;
291    gettimeofday(&tv, 0);
292    return tv.tv_sec * (suseconds_t) 1000000 + tv.tv_usec;
293}
294
295#define log_event_print(x...) INFO(x)
296
297#else
298
299#define log_event_print(fmt, args...)   do { } while (0)
300#define get_usecs()                     0
301
302#endif
303
304static void parse_event(const char *msg, struct uevent *uevent)
305{
306    uevent->action = "";
307    uevent->path = "";
308    uevent->subsystem = "";
309    uevent->firmware = "";
310    uevent->major = -1;
311    uevent->minor = -1;
312
313        /* currently ignoring SEQNUM */
314    while(*msg) {
315        if(!strncmp(msg, "ACTION=", 7)) {
316            msg += 7;
317            uevent->action = msg;
318        } else if(!strncmp(msg, "DEVPATH=", 8)) {
319            msg += 8;
320            uevent->path = msg;
321        } else if(!strncmp(msg, "SUBSYSTEM=", 10)) {
322            msg += 10;
323            uevent->subsystem = msg;
324        } else if(!strncmp(msg, "FIRMWARE=", 9)) {
325            msg += 9;
326            uevent->firmware = msg;
327        } else if(!strncmp(msg, "MAJOR=", 6)) {
328            msg += 6;
329            uevent->major = atoi(msg);
330        } else if(!strncmp(msg, "MINOR=", 6)) {
331            msg += 6;
332            uevent->minor = atoi(msg);
333        }
334
335            /* advance to after the next \0 */
336        while(*msg++)
337            ;
338    }
339
340    log_event_print("event { '%s', '%s', '%s', '%s', %d, %d }\n",
341                    uevent->action, uevent->path, uevent->subsystem,
342                    uevent->firmware, uevent->major, uevent->minor);
343}
344
345static void handle_device_event(struct uevent *uevent)
346{
347    char devpath[96];
348    char *base, *name;
349    int block;
350
351        /* if it's not a /dev device, nothing to do */
352    if((uevent->major < 0) || (uevent->minor < 0))
353        return;
354
355        /* do we have a name? */
356    name = strrchr(uevent->path, '/');
357    if(!name)
358        return;
359    name++;
360
361        /* too-long names would overrun our buffer */
362    if(strlen(name) > 64)
363        return;
364
365        /* are we block or char? where should we live? */
366    if(!strncmp(uevent->subsystem, "block", 5)) {
367        block = 1;
368        base = "/dev/block/";
369        mkdir(base, 0755);
370    } else {
371        block = 0;
372            /* this should probably be configurable somehow */
373        if(!strncmp(uevent->subsystem, "graphics", 8)) {
374            base = "/dev/graphics/";
375            mkdir(base, 0755);
376        } else if (!strncmp(uevent->subsystem, "oncrpc", 6)) {
377            base = "/dev/oncrpc/";
378            mkdir(base, 0755);
379        } else if (!strncmp(uevent->subsystem, "adsp", 4)) {
380            base = "/dev/adsp/";
381            mkdir(base, 0755);
382      } else if(!strncmp(uevent->subsystem, "input", 5)) {
383            base = "/dev/input/";
384            mkdir(base, 0755);
385        } else if(!strncmp(uevent->subsystem, "mtd", 3)) {
386            base = "/dev/mtd/";
387            mkdir(base, 0755);
388        } else if(!strncmp(uevent->subsystem, "misc", 4) &&
389                    !strncmp(name, "log_", 4)) {
390            base = "/dev/log/";
391            mkdir(base, 0755);
392            name += 4;
393        } else
394            base = "/dev/";
395    }
396
397    snprintf(devpath, sizeof(devpath), "%s%s", base, name);
398
399    if(!strcmp(uevent->action, "add")) {
400        make_device(devpath, block, uevent->major, uevent->minor);
401        return;
402    }
403
404    if(!strcmp(uevent->action, "remove")) {
405        unlink(devpath);
406        return;
407    }
408}
409
410static int load_firmware(int fw_fd, int loading_fd, int data_fd)
411{
412    struct stat st;
413    long len_to_copy;
414    int ret = 0;
415
416    if(fstat(fw_fd, &st) < 0)
417        return -1;
418    len_to_copy = st.st_size;
419
420    write(loading_fd, "1", 1);  /* start transfer */
421
422    while (len_to_copy > 0) {
423        char buf[PAGE_SIZE];
424        ssize_t nr;
425
426        nr = read(fw_fd, buf, sizeof(buf));
427        if(!nr)
428            break;
429        if(nr < 0) {
430            ret = -1;
431            break;
432        }
433
434        len_to_copy -= nr;
435        while (nr > 0) {
436            ssize_t nw = 0;
437
438            nw = write(data_fd, buf + nw, nr);
439            if(nw <= 0) {
440                ret = -1;
441                goto out;
442            }
443            nr -= nw;
444        }
445    }
446
447out:
448    if(!ret)
449        write(loading_fd, "0", 1);  /* successful end of transfer */
450    else
451        write(loading_fd, "-1", 2); /* abort transfer */
452
453    return ret;
454}
455
456static void process_firmware_event(struct uevent *uevent)
457{
458    char *root, *loading, *data, *file;
459    int l, loading_fd, data_fd, fw_fd;
460
461    log_event_print("firmware event { '%s', '%s' }\n",
462                    uevent->path, uevent->firmware);
463
464    l = asprintf(&root, SYSFS_PREFIX"%s/", uevent->path);
465    if (l == -1)
466        return;
467
468    l = asprintf(&loading, "%sloading", root);
469    if (l == -1)
470        goto root_free_out;
471
472    l = asprintf(&data, "%sdata", root);
473    if (l == -1)
474        goto loading_free_out;
475
476    l = asprintf(&file, FIRMWARE_DIR"/%s", uevent->firmware);
477    if (l == -1)
478        goto data_free_out;
479
480    loading_fd = open(loading, O_WRONLY);
481    if(loading_fd < 0)
482        goto file_free_out;
483
484    data_fd = open(data, O_WRONLY);
485    if(data_fd < 0)
486        goto loading_close_out;
487
488    fw_fd = open(file, O_RDONLY);
489    if(fw_fd < 0)
490        goto data_close_out;
491
492    if(!load_firmware(fw_fd, loading_fd, data_fd))
493        log_event_print("firmware copy success { '%s', '%s' }\n", root, file);
494    else
495        log_event_print("firmware copy failure { '%s', '%s' }\n", root, file);
496
497    close(fw_fd);
498data_close_out:
499    close(data_fd);
500loading_close_out:
501    close(loading_fd);
502file_free_out:
503    free(file);
504data_free_out:
505    free(data);
506loading_free_out:
507    free(loading);
508root_free_out:
509    free(root);
510}
511
512static void handle_firmware_event(struct uevent *uevent)
513{
514    pid_t pid;
515
516    if(strcmp(uevent->subsystem, "firmware"))
517        return;
518
519    if(strcmp(uevent->action, "add"))
520        return;
521
522    /* we fork, to avoid making large memory allocations in init proper */
523    pid = fork();
524    if (!pid) {
525        process_firmware_event(uevent);
526        exit(EXIT_SUCCESS);
527    }
528}
529
530#define UEVENT_MSG_LEN  1024
531void handle_device_fd(int fd)
532{
533    char msg[UEVENT_MSG_LEN+2];
534    int n;
535
536    while((n = recv(fd, msg, UEVENT_MSG_LEN, 0)) > 0) {
537        struct uevent uevent;
538
539        if(n == UEVENT_MSG_LEN)   /* overflow -- discard */
540            continue;
541
542        msg[n] = '\0';
543        msg[n+1] = '\0';
544
545        parse_event(msg, &uevent);
546
547        handle_device_event(&uevent);
548        handle_firmware_event(&uevent);
549    }
550}
551
552/* Coldboot walks parts of the /sys tree and pokes the uevent files
553** to cause the kernel to regenerate device add events that happened
554** before init's device manager was started
555**
556** We drain any pending events from the netlink socket every time
557** we poke another uevent file to make sure we don't overrun the
558** socket's buffer.
559*/
560
561static void do_coldboot(int event_fd, DIR *d)
562{
563    struct dirent *de;
564    int dfd, fd;
565
566    dfd = dirfd(d);
567
568    fd = openat(dfd, "uevent", O_WRONLY);
569    if(fd >= 0) {
570        write(fd, "add\n", 4);
571        close(fd);
572        handle_device_fd(event_fd);
573    }
574
575    while((de = readdir(d))) {
576        DIR *d2;
577
578        if(de->d_type != DT_DIR || de->d_name[0] == '.')
579            continue;
580
581        fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
582        if(fd < 0)
583            continue;
584
585        d2 = fdopendir(fd);
586        if(d2 == 0)
587            close(fd);
588        else {
589            do_coldboot(event_fd, d2);
590            closedir(d2);
591        }
592    }
593}
594
595static void coldboot(int event_fd, const char *path)
596{
597    DIR *d = opendir(path);
598    if(d) {
599        do_coldboot(event_fd, d);
600        closedir(d);
601    }
602}
603
604int device_init(void)
605{
606    suseconds_t t0, t1;
607    int fd;
608
609    fd = open_uevent_socket();
610    if(fd < 0)
611        return -1;
612
613    fcntl(fd, F_SETFD, FD_CLOEXEC);
614    fcntl(fd, F_SETFL, O_NONBLOCK);
615
616    t0 = get_usecs();
617    coldboot(fd, "/sys/class");
618    coldboot(fd, "/sys/block");
619    coldboot(fd, "/sys/devices");
620    t1 = get_usecs();
621
622    log_event_print("coldboot %ld uS\n", ((long) (t1 - t0)));
623
624    return fd;
625}
626