devices.c revision 4f6e8d7a00cbeda1e70cc15be9c4af1018bdad53 
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/smd0",          0640,   AID_RADIO,      AID_RADIO,      0 },
124    { "/dev/qmi",           0640,   AID_RADIO,      AID_RADIO,      0 },
125    { "/dev/qmi0",          0640,   AID_RADIO,      AID_RADIO,      0 },
126    { "/dev/qmi1",          0640,   AID_RADIO,      AID_RADIO,      0 },
127    { "/dev/qmi2",          0640,   AID_RADIO,      AID_RADIO,      0 },
128    { "/dev/htc-acoustic",  0640,   AID_RADIO,      AID_RADIO,      0 },
129    { NULL, 0, 0, 0, 0 },
130};
131
132/* devperms_partners list and perm_node are for hardware specific /dev entries */
133struct perm_node {
134    struct perms_ dp;
135    struct listnode plist;
136};
137list_declare(devperms_partners);
138
139/*
140 * Permission override when in emulator mode, must be parsed before
141 * system properties is initalized.
142 */
143static int qemu_perm_count;
144static struct perms_ qemu_perms[MAX_QEMU_PERM + 1];
145
146int add_devperms_partners(const char *name, mode_t perm, unsigned int uid,
147                        unsigned int gid, unsigned short prefix) {
148    int size;
149    struct perm_node *node = malloc(sizeof (struct perm_node));
150    if (!node)
151        return -ENOMEM;
152
153    size = strlen(name) + 1;
154    if ((node->dp.name = malloc(size)) == NULL)
155        return -ENOMEM;
156
157    memcpy(node->dp.name, name, size);
158    node->dp.perm = perm;
159    node->dp.uid = uid;
160    node->dp.gid = gid;
161    node->dp.prefix = prefix;
162
163    list_add_tail(&devperms_partners, &node->plist);
164    return 0;
165}
166
167void qemu_init(void) {
168    qemu_perm_count = 0;
169    memset(&qemu_perms, 0, sizeof(qemu_perms));
170}
171
172static int qemu_perm(const char* name, mode_t perm, unsigned int uid,
173                         unsigned int gid, unsigned short prefix)
174{
175    char *buf;
176    if (qemu_perm_count == MAX_QEMU_PERM)
177        return -ENOSPC;
178
179    buf = malloc(strlen(name) + 1);
180    if (!buf)
181        return -errno;
182
183    strlcpy(buf, name, strlen(name) + 1);
184    qemu_perms[qemu_perm_count].name = buf;
185    qemu_perms[qemu_perm_count].perm = perm;
186    qemu_perms[qemu_perm_count].uid = uid;
187    qemu_perms[qemu_perm_count].gid = gid;
188    qemu_perms[qemu_perm_count].prefix = prefix;
189
190    qemu_perm_count++;
191    return 0;
192}
193
194/* Permission overrides for emulator that are parsed from /proc/cmdline. */
195void qemu_cmdline(const char* name, const char *value)
196{
197    char *buf;
198    if (!strcmp(name, "android.ril")) {
199        /* cmd line params currently assume /dev/ prefix */
200        if (asprintf(&buf, CMDLINE_PREFIX"/%s", value) == -1) {
201            return;
202        }
203        INFO("nani- buf:: %s\n", buf);
204        qemu_perm(buf, 0660, AID_RADIO, AID_ROOT, 0);
205    }
206}
207
208static int get_device_perm_inner(struct perms_ *perms, const char *path,
209                                    unsigned *uid, unsigned *gid, mode_t *perm)
210{
211    int i;
212    for(i = 0; perms[i].name; i++) {
213
214        if(perms[i].prefix) {
215            if(strncmp(path, perms[i].name, strlen(perms[i].name)))
216                continue;
217        } else {
218            if(strcmp(path, perms[i].name))
219                continue;
220        }
221        *uid = perms[i].uid;
222        *gid = perms[i].gid;
223        *perm = perms[i].perm;
224        return 0;
225    }
226    return -1;
227}
228
229/* First checks for emulator specific permissions specified in /proc/cmdline. */
230static mode_t get_device_perm(const char *path, unsigned *uid, unsigned *gid)
231{
232    mode_t perm;
233
234    if (get_device_perm_inner(qemu_perms, path, uid, gid, &perm) == 0) {
235        return perm;
236    } else if (get_device_perm_inner(devperms, path, uid, gid, &perm) == 0) {
237        return perm;
238    } else {
239        struct listnode *node;
240        struct perm_node *perm_node;
241        struct perms_ *dp;
242
243        /* Check partners list. */
244        list_for_each(node, &devperms_partners) {
245            perm_node = node_to_item(node, struct perm_node, plist);
246            dp = &perm_node->dp;
247
248            if (dp->prefix) {
249                if (strncmp(path, dp->name, strlen(dp->name)))
250                    continue;
251            } else {
252                if (strcmp(path, dp->name))
253                    continue;
254            }
255            /* Found perm in partner list. */
256            *uid = dp->uid;
257            *gid = dp->gid;
258            return dp->perm;
259        }
260        /* Default if nothing found. */
261        *uid = 0;
262        *gid = 0;
263        return 0600;
264    }
265}
266
267static void make_device(const char *path, int block, int major, int minor)
268{
269    unsigned uid;
270    unsigned gid;
271    mode_t mode;
272    dev_t dev;
273
274    if(major > 255 || minor > 255)
275        return;
276
277    mode = get_device_perm(path, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
278    dev = (major << 8) | minor;
279    mknod(path, mode, dev);
280    chown(path, uid, gid);
281}
282
283#ifdef LOG_UEVENTS
284
285static inline suseconds_t get_usecs(void)
286{
287    struct timeval tv;
288    gettimeofday(&tv, 0);
289    return tv.tv_sec * (suseconds_t) 1000000 + tv.tv_usec;
290}
291
292#define log_event_print(x...) INFO(x)
293
294#else
295
296#define log_event_print(fmt, args...)   do { } while (0)
297#define get_usecs()                     0
298
299#endif
300
301static void parse_event(const char *msg, struct uevent *uevent)
302{
303    uevent->action = "";
304    uevent->path = "";
305    uevent->subsystem = "";
306    uevent->firmware = "";
307    uevent->major = -1;
308    uevent->minor = -1;
309
310        /* currently ignoring SEQNUM */
311    while(*msg) {
312        if(!strncmp(msg, "ACTION=", 7)) {
313            msg += 7;
314            uevent->action = msg;
315        } else if(!strncmp(msg, "DEVPATH=", 8)) {
316            msg += 8;
317            uevent->path = msg;
318        } else if(!strncmp(msg, "SUBSYSTEM=", 10)) {
319            msg += 10;
320            uevent->subsystem = msg;
321        } else if(!strncmp(msg, "FIRMWARE=", 9)) {
322            msg += 9;
323            uevent->firmware = msg;
324        } else if(!strncmp(msg, "MAJOR=", 6)) {
325            msg += 6;
326            uevent->major = atoi(msg);
327        } else if(!strncmp(msg, "MINOR=", 6)) {
328            msg += 6;
329            uevent->minor = atoi(msg);
330        }
331
332            /* advance to after the next \0 */
333        while(*msg++)
334            ;
335    }
336
337    log_event_print("event { '%s', '%s', '%s', '%s', %d, %d }\n",
338                    uevent->action, uevent->path, uevent->subsystem,
339                    uevent->firmware, uevent->major, uevent->minor);
340}
341
342static void handle_device_event(struct uevent *uevent)
343{
344    char devpath[96];
345    char *base, *name;
346    int block;
347
348        /* if it's not a /dev device, nothing to do */
349    if((uevent->major < 0) || (uevent->minor < 0))
350        return;
351
352        /* do we have a name? */
353    name = strrchr(uevent->path, '/');
354    if(!name)
355        return;
356    name++;
357
358        /* too-long names would overrun our buffer */
359    if(strlen(name) > 64)
360        return;
361
362        /* are we block or char? where should we live? */
363    if(!strncmp(uevent->path, "/block", 6)) {
364        block = 1;
365        base = "/dev/block/";
366        mkdir(base, 0755);
367    } else {
368        block = 0;
369            /* this should probably be configurable somehow */
370        if(!strncmp(uevent->path, "/class/graphics/", 16)) {
371            base = "/dev/graphics/";
372            mkdir(base, 0755);
373        } else if (!strncmp(uevent->path, "/class/oncrpc/", 14)) {
374            base = "/dev/oncrpc/";
375            mkdir(base, 0755);
376        } else if (!strncmp(uevent->path, "/class/adsp/", 12)) {
377            base = "/dev/adsp/";
378            mkdir(base, 0755);
379      } else if(!strncmp(uevent->path, "/class/input/", 13)) {
380            base = "/dev/input/";
381            mkdir(base, 0755);
382        } else if(!strncmp(uevent->path, "/class/mtd/", 11)) {
383            base = "/dev/mtd/";
384            mkdir(base, 0755);
385        } else if(!strncmp(uevent->path, "/class/misc/", 12) &&
386                    !strncmp(name, "log_", 4)) {
387            base = "/dev/log/";
388            mkdir(base, 0755);
389            name += 4;
390        } else
391            base = "/dev/";
392    }
393
394    snprintf(devpath, sizeof(devpath), "%s%s", base, name);
395
396    if(!strcmp(uevent->action, "add")) {
397        make_device(devpath, block, uevent->major, uevent->minor);
398        return;
399    }
400
401    if(!strcmp(uevent->action, "remove")) {
402        unlink(devpath);
403        return;
404    }
405}
406
407static int load_firmware(int fw_fd, int loading_fd, int data_fd)
408{
409    struct stat st;
410    long len_to_copy;
411    int ret = 0;
412
413    if(fstat(fw_fd, &st) < 0)
414        return -1;
415    len_to_copy = st.st_size;
416
417    write(loading_fd, "1", 1);  /* start transfer */
418
419    while (len_to_copy > 0) {
420        char buf[PAGE_SIZE];
421        ssize_t nr;
422
423        nr = read(fw_fd, buf, sizeof(buf));
424        if(!nr)
425            break;
426        if(nr < 0) {
427            ret = -1;
428            break;
429        }
430
431        len_to_copy -= nr;
432        while (nr > 0) {
433            ssize_t nw = 0;
434
435            nw = write(data_fd, buf + nw, nr);
436            if(nw <= 0) {
437                ret = -1;
438                goto out;
439            }
440            nr -= nw;
441        }
442    }
443
444out:
445    if(!ret)
446        write(loading_fd, "0", 1);  /* successful end of transfer */
447    else
448        write(loading_fd, "-1", 2); /* abort transfer */
449
450    return ret;
451}
452
453static void process_firmware_event(struct uevent *uevent)
454{
455    char *root, *loading, *data, *file;
456    int l, loading_fd, data_fd, fw_fd;
457
458    log_event_print("firmware event { '%s', '%s' }\n",
459                    uevent->path, uevent->firmware);
460
461    l = asprintf(&root, SYSFS_PREFIX"%s/", uevent->path);
462    if (l == -1)
463        return;
464
465    l = asprintf(&loading, "%sloading", root);
466    if (l == -1)
467        goto root_free_out;
468
469    l = asprintf(&data, "%sdata", root);
470    if (l == -1)
471        goto loading_free_out;
472
473    l = asprintf(&file, FIRMWARE_DIR"/%s", uevent->firmware);
474    if (l == -1)
475        goto data_free_out;
476
477    loading_fd = open(loading, O_WRONLY);
478    if(loading_fd < 0)
479        goto file_free_out;
480
481    data_fd = open(data, O_WRONLY);
482    if(data_fd < 0)
483        goto loading_close_out;
484
485    fw_fd = open(file, O_RDONLY);
486    if(fw_fd < 0)
487        goto data_close_out;
488
489    if(!load_firmware(fw_fd, loading_fd, data_fd))
490        log_event_print("firmware copy success { '%s', '%s' }\n", root, file);
491    else
492        log_event_print("firmware copy failure { '%s', '%s' }\n", root, file);
493
494    close(fw_fd);
495data_close_out:
496    close(data_fd);
497loading_close_out:
498    close(loading_fd);
499file_free_out:
500    free(file);
501data_free_out:
502    free(data);
503loading_free_out:
504    free(loading);
505root_free_out:
506    free(root);
507}
508
509static void handle_firmware_event(struct uevent *uevent)
510{
511    pid_t pid;
512
513    if(strcmp(uevent->subsystem, "firmware"))
514        return;
515
516    if(strcmp(uevent->action, "add"))
517        return;
518
519    /* we fork, to avoid making large memory allocations in init proper */
520    pid = fork();
521    if (!pid) {
522        process_firmware_event(uevent);
523        exit(EXIT_SUCCESS);
524    }
525}
526
527#define UEVENT_MSG_LEN  1024
528void handle_device_fd(int fd)
529{
530    char msg[UEVENT_MSG_LEN+2];
531    int n;
532
533    while((n = recv(fd, msg, UEVENT_MSG_LEN, 0)) > 0) {
534        struct uevent uevent;
535
536        if(n == UEVENT_MSG_LEN)   /* overflow -- discard */
537            continue;
538
539        msg[n] = '\0';
540        msg[n+1] = '\0';
541
542        parse_event(msg, &uevent);
543
544        handle_device_event(&uevent);
545        handle_firmware_event(&uevent);
546    }
547}
548
549/* Coldboot walks parts of the /sys tree and pokes the uevent files
550** to cause the kernel to regenerate device add events that happened
551** before init's device manager was started
552**
553** We drain any pending events from the netlink socket every time
554** we poke another uevent file to make sure we don't overrun the
555** socket's buffer.
556*/
557
558static void do_coldboot(int event_fd, DIR *d)
559{
560    struct dirent *de;
561    int dfd, fd;
562
563    dfd = dirfd(d);
564
565    fd = openat(dfd, "uevent", O_WRONLY);
566    if(fd >= 0) {
567        write(fd, "add\n", 4);
568        close(fd);
569        handle_device_fd(event_fd);
570    }
571
572    while((de = readdir(d))) {
573        DIR *d2;
574
575        if(de->d_type != DT_DIR || de->d_name[0] == '.')
576            continue;
577
578        fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
579        if(fd < 0)
580            continue;
581
582        d2 = fdopendir(fd);
583        if(d2 == 0)
584            close(fd);
585        else {
586            do_coldboot(event_fd, d2);
587            closedir(d2);
588        }
589    }
590}
591
592static void coldboot(int event_fd, const char *path)
593{
594    DIR *d = opendir(path);
595    if(d) {
596        do_coldboot(event_fd, d);
597        closedir(d);
598    }
599}
600
601int device_init(void)
602{
603    suseconds_t t0, t1;
604    int fd;
605
606    fd = open_uevent_socket();
607    if(fd < 0)
608        return -1;
609
610    fcntl(fd, F_SETFD, FD_CLOEXEC);
611    fcntl(fd, F_SETFL, O_NONBLOCK);
612
613    t0 = get_usecs();
614    coldboot(fd, "/sys/class");
615    coldboot(fd, "/sys/block");
616    coldboot(fd, "/sys/devices");
617    t1 = get_usecs();
618
619    log_event_print("coldboot %ld uS\n", ((long) (t1 - t0)));
620
621    return fd;
622}
623