devices.c revision 6405c6953fa02d41d9f6377f4cdb947604f481c4 
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    /* the msm hw3d client device node is world writable/readable. */
99    { "/dev/msm_hw3dc",     0666,   AID_ROOT,       AID_ROOT,       0 },
100
101    /* gpu driver for adreno200 is globally accessible */
102    { "/dev/kgsl",          0666,   AID_ROOT,       AID_ROOT,       0 },
103
104        /* these should not be world writable */
105    { "/dev/diag",          0660,   AID_RADIO,      AID_RADIO,        0 },
106    { "/dev/diag_arm9",     0660,   AID_RADIO,      AID_RADIO,        0 },
107    { "/dev/android_adb",   0660,   AID_ADB,        AID_ADB,        0 },
108    { "/dev/android_adb_enable",   0660,   AID_ADB,        AID_ADB,        0 },
109    { "/dev/ttyMSM0",       0600,   AID_BLUETOOTH,  AID_BLUETOOTH,  0 },
110    { "/dev/ttyHS0",        0600,   AID_BLUETOOTH,  AID_BLUETOOTH,  0 },
111    { "/dev/uinput",        0660,   AID_SYSTEM,     AID_BLUETOOTH,  0 },
112    { "/dev/alarm",         0664,   AID_SYSTEM,     AID_RADIO,      0 },
113    { "/dev/tty0",          0660,   AID_ROOT,       AID_SYSTEM,     0 },
114    { "/dev/graphics/",     0660,   AID_ROOT,       AID_GRAPHICS,   1 },
115    { "/dev/msm_hw3dm",     0660,   AID_SYSTEM,     AID_GRAPHICS,   0 },
116    { "/dev/input/",        0660,   AID_ROOT,       AID_INPUT,      1 },
117    { "/dev/eac",           0660,   AID_ROOT,       AID_AUDIO,      0 },
118    { "/dev/cam",           0660,   AID_ROOT,       AID_CAMERA,     0 },
119    { "/dev/pmem",          0660,   AID_SYSTEM,     AID_GRAPHICS,   0 },
120    { "/dev/pmem_adsp",     0660,   AID_SYSTEM,     AID_AUDIO,      1 },
121    { "/dev/pmem_camera",   0660,   AID_SYSTEM,     AID_CAMERA,     1 },
122    { "/dev/oncrpc/",       0660,   AID_ROOT,       AID_SYSTEM,     1 },
123    { "/dev/adsp/",         0660,   AID_SYSTEM,     AID_AUDIO,      1 },
124    { "/dev/snd/",          0660,   AID_SYSTEM,     AID_AUDIO,      1 },
125    { "/dev/mt9t013",       0660,   AID_SYSTEM,     AID_SYSTEM,     0 },
126    { "/dev/msm_camera/",   0660,   AID_SYSTEM,     AID_SYSTEM,     1 },
127    { "/dev/akm8976_daemon",0640,   AID_COMPASS,    AID_SYSTEM,     0 },
128    { "/dev/akm8976_aot",   0640,   AID_COMPASS,    AID_SYSTEM,     0 },
129    { "/dev/akm8973_daemon",0640,   AID_COMPASS,    AID_SYSTEM,     0 },
130    { "/dev/akm8973_aot",   0640,   AID_COMPASS,    AID_SYSTEM,     0 },
131    { "/dev/bma150",        0640,   AID_COMPASS,    AID_SYSTEM,     0 },
132    { "/dev/cm3602",        0640,   AID_COMPASS,    AID_SYSTEM,     0 },
133    { "/dev/akm8976_pffd",  0640,   AID_COMPASS,    AID_SYSTEM,     0 },
134    { "/dev/lightsensor",   0640,   AID_SYSTEM,     AID_SYSTEM,     0 },
135    { "/dev/msm_pcm_out",   0660,   AID_SYSTEM,     AID_AUDIO,      1 },
136    { "/dev/msm_pcm_in",    0660,   AID_SYSTEM,     AID_AUDIO,      1 },
137    { "/dev/msm_pcm_ctl",   0660,   AID_SYSTEM,     AID_AUDIO,      1 },
138    { "/dev/msm_snd",       0660,   AID_SYSTEM,     AID_AUDIO,      1 },
139    { "/dev/msm_mp3",       0660,   AID_SYSTEM,     AID_AUDIO,      1 },
140    { "/dev/audience_a1026", 0660,   AID_SYSTEM,     AID_AUDIO,      1 },
141    { "/dev/msm_audpre",    0660,   AID_SYSTEM,     AID_AUDIO,      0 },
142    { "/dev/msm_audio_ctl", 0660,   AID_SYSTEM,     AID_AUDIO,      0 },
143    { "/dev/htc-acoustic",  0660,   AID_SYSTEM,     AID_AUDIO,      0 },
144    { "/dev/vdec",          0660,   AID_SYSTEM,     AID_AUDIO,      0 },
145    { "/dev/q6venc",        0660,   AID_SYSTEM,     AID_AUDIO,      0 },
146    { "/dev/snd/dsp",       0660,   AID_SYSTEM,     AID_AUDIO,      0 },
147    { "/dev/snd/dsp1",      0660,   AID_SYSTEM,     AID_AUDIO,      0 },
148    { "/dev/snd/mixer",     0660,   AID_SYSTEM,     AID_AUDIO,      0 },
149    { "/dev/smd0",          0640,   AID_RADIO,      AID_RADIO,      0 },
150    { "/dev/qemu_trace",    0666,   AID_SYSTEM,     AID_SYSTEM,     0 },
151    { "/dev/qmi",           0640,   AID_RADIO,      AID_RADIO,      0 },
152    { "/dev/qmi0",          0640,   AID_RADIO,      AID_RADIO,      0 },
153    { "/dev/qmi1",          0640,   AID_RADIO,      AID_RADIO,      0 },
154    { "/dev/qmi2",          0640,   AID_RADIO,      AID_RADIO,      0 },
155        /* CDMA radio interface MUX */
156    { "/dev/ts0710mux",     0640,   AID_RADIO,      AID_RADIO,      1 },
157    { "/dev/ppp",           0660,   AID_RADIO,      AID_VPN,        0 },
158    { "/dev/tun",           0640,   AID_VPN,        AID_VPN,        0 },
159    { NULL, 0, 0, 0, 0 },
160};
161
162/* devperms_partners list and perm_node are for hardware specific /dev entries */
163struct perm_node {
164    struct perms_ dp;
165    struct listnode plist;
166};
167list_declare(devperms_partners);
168
169/*
170 * Permission override when in emulator mode, must be parsed before
171 * system properties is initalized.
172 */
173static int qemu_perm_count;
174static struct perms_ qemu_perms[MAX_QEMU_PERM + 1];
175
176int add_devperms_partners(const char *name, mode_t perm, unsigned int uid,
177                        unsigned int gid, unsigned short prefix) {
178    int size;
179    struct perm_node *node = malloc(sizeof (struct perm_node));
180    if (!node)
181        return -ENOMEM;
182
183    size = strlen(name) + 1;
184    if ((node->dp.name = malloc(size)) == NULL)
185        return -ENOMEM;
186
187    memcpy(node->dp.name, name, size);
188    node->dp.perm = perm;
189    node->dp.uid = uid;
190    node->dp.gid = gid;
191    node->dp.prefix = prefix;
192
193    list_add_tail(&devperms_partners, &node->plist);
194    return 0;
195}
196
197void qemu_init(void) {
198    qemu_perm_count = 0;
199    memset(&qemu_perms, 0, sizeof(qemu_perms));
200}
201
202static int qemu_perm(const char* name, mode_t perm, unsigned int uid,
203                         unsigned int gid, unsigned short prefix)
204{
205    char *buf;
206    if (qemu_perm_count == MAX_QEMU_PERM)
207        return -ENOSPC;
208
209    buf = malloc(strlen(name) + 1);
210    if (!buf)
211        return -errno;
212
213    strlcpy(buf, name, strlen(name) + 1);
214    qemu_perms[qemu_perm_count].name = buf;
215    qemu_perms[qemu_perm_count].perm = perm;
216    qemu_perms[qemu_perm_count].uid = uid;
217    qemu_perms[qemu_perm_count].gid = gid;
218    qemu_perms[qemu_perm_count].prefix = prefix;
219
220    qemu_perm_count++;
221    return 0;
222}
223
224/* Permission overrides for emulator that are parsed from /proc/cmdline. */
225void qemu_cmdline(const char* name, const char *value)
226{
227    char *buf;
228    if (!strcmp(name, "android.ril")) {
229        /* cmd line params currently assume /dev/ prefix */
230        if (asprintf(&buf, CMDLINE_PREFIX"/%s", value) == -1) {
231            return;
232        }
233        INFO("nani- buf:: %s\n", buf);
234        qemu_perm(buf, 0660, AID_RADIO, AID_ROOT, 0);
235    }
236}
237
238static int get_device_perm_inner(struct perms_ *perms, const char *path,
239                                    unsigned *uid, unsigned *gid, mode_t *perm)
240{
241    int i;
242    for(i = 0; perms[i].name; i++) {
243
244        if(perms[i].prefix) {
245            if(strncmp(path, perms[i].name, strlen(perms[i].name)))
246                continue;
247        } else {
248            if(strcmp(path, perms[i].name))
249                continue;
250        }
251        *uid = perms[i].uid;
252        *gid = perms[i].gid;
253        *perm = perms[i].perm;
254        return 0;
255    }
256    return -1;
257}
258
259/* First checks for emulator specific permissions specified in /proc/cmdline. */
260static mode_t get_device_perm(const char *path, unsigned *uid, unsigned *gid)
261{
262    mode_t perm;
263
264    if (get_device_perm_inner(qemu_perms, path, uid, gid, &perm) == 0) {
265        return perm;
266    } else if (get_device_perm_inner(devperms, path, uid, gid, &perm) == 0) {
267        return perm;
268    } else {
269        struct listnode *node;
270        struct perm_node *perm_node;
271        struct perms_ *dp;
272
273        /* Check partners list. */
274        list_for_each(node, &devperms_partners) {
275            perm_node = node_to_item(node, struct perm_node, plist);
276            dp = &perm_node->dp;
277
278            if (dp->prefix) {
279                if (strncmp(path, dp->name, strlen(dp->name)))
280                    continue;
281            } else {
282                if (strcmp(path, dp->name))
283                    continue;
284            }
285            /* Found perm in partner list. */
286            *uid = dp->uid;
287            *gid = dp->gid;
288            return dp->perm;
289        }
290        /* Default if nothing found. */
291        *uid = 0;
292        *gid = 0;
293        return 0600;
294    }
295}
296
297static void make_device(const char *path, int block, int major, int minor)
298{
299    unsigned uid;
300    unsigned gid;
301    mode_t mode;
302    dev_t dev;
303
304    if(major > 255 || minor > 255)
305        return;
306
307    mode = get_device_perm(path, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
308    dev = (major << 8) | minor;
309    /* Temporarily change egid to avoid race condition setting the gid of the
310     * device node. Unforunately changing the euid would prevent creation of
311     * some device nodes, so the uid has to be set with chown() and is still
312     * racy. Fixing the gid race at least fixed the issue with system_server
313     * opening dynamic input devices under the AID_INPUT gid. */
314    setegid(gid);
315    mknod(path, mode, dev);
316    chown(path, uid, -1);
317    setegid(AID_ROOT);
318}
319
320#if LOG_UEVENTS
321
322static inline suseconds_t get_usecs(void)
323{
324    struct timeval tv;
325    gettimeofday(&tv, 0);
326    return tv.tv_sec * (suseconds_t) 1000000 + tv.tv_usec;
327}
328
329#define log_event_print(x...) INFO(x)
330
331#else
332
333#define log_event_print(fmt, args...)   do { } while (0)
334#define get_usecs()                     0
335
336#endif
337
338static void parse_event(const char *msg, struct uevent *uevent)
339{
340    uevent->action = "";
341    uevent->path = "";
342    uevent->subsystem = "";
343    uevent->firmware = "";
344    uevent->major = -1;
345    uevent->minor = -1;
346
347        /* currently ignoring SEQNUM */
348    while(*msg) {
349        if(!strncmp(msg, "ACTION=", 7)) {
350            msg += 7;
351            uevent->action = msg;
352        } else if(!strncmp(msg, "DEVPATH=", 8)) {
353            msg += 8;
354            uevent->path = msg;
355        } else if(!strncmp(msg, "SUBSYSTEM=", 10)) {
356            msg += 10;
357            uevent->subsystem = msg;
358        } else if(!strncmp(msg, "FIRMWARE=", 9)) {
359            msg += 9;
360            uevent->firmware = msg;
361        } else if(!strncmp(msg, "MAJOR=", 6)) {
362            msg += 6;
363            uevent->major = atoi(msg);
364        } else if(!strncmp(msg, "MINOR=", 6)) {
365            msg += 6;
366            uevent->minor = atoi(msg);
367        }
368
369            /* advance to after the next \0 */
370        while(*msg++)
371            ;
372    }
373
374    log_event_print("event { '%s', '%s', '%s', '%s', %d, %d }\n",
375                    uevent->action, uevent->path, uevent->subsystem,
376                    uevent->firmware, uevent->major, uevent->minor);
377}
378
379static void handle_device_event(struct uevent *uevent)
380{
381    char devpath[96];
382    char *base, *name;
383    int block;
384
385        /* if it's not a /dev device, nothing to do */
386    if((uevent->major < 0) || (uevent->minor < 0))
387        return;
388
389        /* do we have a name? */
390    name = strrchr(uevent->path, '/');
391    if(!name)
392        return;
393    name++;
394
395        /* too-long names would overrun our buffer */
396    if(strlen(name) > 64)
397        return;
398
399        /* are we block or char? where should we live? */
400    if(!strncmp(uevent->subsystem, "block", 5)) {
401        block = 1;
402        base = "/dev/block/";
403        mkdir(base, 0755);
404    } else {
405        block = 0;
406            /* this should probably be configurable somehow */
407        if(!strncmp(uevent->subsystem, "graphics", 8)) {
408            base = "/dev/graphics/";
409            mkdir(base, 0755);
410        } else if (!strncmp(uevent->subsystem, "oncrpc", 6)) {
411            base = "/dev/oncrpc/";
412            mkdir(base, 0755);
413        } else if (!strncmp(uevent->subsystem, "adsp", 4)) {
414            base = "/dev/adsp/";
415            mkdir(base, 0755);
416        } else if (!strncmp(uevent->subsystem, "msm_camera", 10)) {
417            base = "/dev/msm_camera/";
418            mkdir(base, 0755);
419        } else if(!strncmp(uevent->subsystem, "input", 5)) {
420            base = "/dev/input/";
421            mkdir(base, 0755);
422        } else if(!strncmp(uevent->subsystem, "mtd", 3)) {
423            base = "/dev/mtd/";
424            mkdir(base, 0755);
425        } else if(!strncmp(uevent->subsystem, "sound", 5)) {
426            base = "/dev/snd/";
427            mkdir(base, 0755);
428        } else if(!strncmp(uevent->subsystem, "misc", 4) &&
429                    !strncmp(name, "log_", 4)) {
430            base = "/dev/log/";
431            mkdir(base, 0755);
432            name += 4;
433        } else
434            base = "/dev/";
435    }
436
437    snprintf(devpath, sizeof(devpath), "%s%s", base, name);
438
439    if(!strcmp(uevent->action, "add")) {
440        make_device(devpath, block, uevent->major, uevent->minor);
441        return;
442    }
443
444    if(!strcmp(uevent->action, "remove")) {
445        unlink(devpath);
446        return;
447    }
448}
449
450static int load_firmware(int fw_fd, int loading_fd, int data_fd)
451{
452    struct stat st;
453    long len_to_copy;
454    int ret = 0;
455
456    if(fstat(fw_fd, &st) < 0)
457        return -1;
458    len_to_copy = st.st_size;
459
460    write(loading_fd, "1", 1);  /* start transfer */
461
462    while (len_to_copy > 0) {
463        char buf[PAGE_SIZE];
464        ssize_t nr;
465
466        nr = read(fw_fd, buf, sizeof(buf));
467        if(!nr)
468            break;
469        if(nr < 0) {
470            ret = -1;
471            break;
472        }
473
474        len_to_copy -= nr;
475        while (nr > 0) {
476            ssize_t nw = 0;
477
478            nw = write(data_fd, buf + nw, nr);
479            if(nw <= 0) {
480                ret = -1;
481                goto out;
482            }
483            nr -= nw;
484        }
485    }
486
487out:
488    if(!ret)
489        write(loading_fd, "0", 1);  /* successful end of transfer */
490    else
491        write(loading_fd, "-1", 2); /* abort transfer */
492
493    return ret;
494}
495
496static void process_firmware_event(struct uevent *uevent)
497{
498    char *root, *loading, *data, *file;
499    int l, loading_fd, data_fd, fw_fd;
500
501    log_event_print("firmware event { '%s', '%s' }\n",
502                    uevent->path, uevent->firmware);
503
504    l = asprintf(&root, SYSFS_PREFIX"%s/", uevent->path);
505    if (l == -1)
506        return;
507
508    l = asprintf(&loading, "%sloading", root);
509    if (l == -1)
510        goto root_free_out;
511
512    l = asprintf(&data, "%sdata", root);
513    if (l == -1)
514        goto loading_free_out;
515
516    l = asprintf(&file, FIRMWARE_DIR"/%s", uevent->firmware);
517    if (l == -1)
518        goto data_free_out;
519
520    loading_fd = open(loading, O_WRONLY);
521    if(loading_fd < 0)
522        goto file_free_out;
523
524    data_fd = open(data, O_WRONLY);
525    if(data_fd < 0)
526        goto loading_close_out;
527
528    fw_fd = open(file, O_RDONLY);
529    if(fw_fd < 0)
530        goto data_close_out;
531
532    if(!load_firmware(fw_fd, loading_fd, data_fd))
533        log_event_print("firmware copy success { '%s', '%s' }\n", root, file);
534    else
535        log_event_print("firmware copy failure { '%s', '%s' }\n", root, file);
536
537    close(fw_fd);
538data_close_out:
539    close(data_fd);
540loading_close_out:
541    close(loading_fd);
542file_free_out:
543    free(file);
544data_free_out:
545    free(data);
546loading_free_out:
547    free(loading);
548root_free_out:
549    free(root);
550}
551
552static void handle_firmware_event(struct uevent *uevent)
553{
554    pid_t pid;
555
556    if(strcmp(uevent->subsystem, "firmware"))
557        return;
558
559    if(strcmp(uevent->action, "add"))
560        return;
561
562    /* we fork, to avoid making large memory allocations in init proper */
563    pid = fork();
564    if (!pid) {
565        process_firmware_event(uevent);
566        exit(EXIT_SUCCESS);
567    }
568}
569
570#define UEVENT_MSG_LEN  1024
571void handle_device_fd(int fd)
572{
573    char msg[UEVENT_MSG_LEN+2];
574    int n;
575
576    while((n = recv(fd, msg, UEVENT_MSG_LEN, 0)) > 0) {
577        struct uevent uevent;
578
579        if(n == UEVENT_MSG_LEN)   /* overflow -- discard */
580            continue;
581
582        msg[n] = '\0';
583        msg[n+1] = '\0';
584
585        parse_event(msg, &uevent);
586
587        handle_device_event(&uevent);
588        handle_firmware_event(&uevent);
589    }
590}
591
592/* Coldboot walks parts of the /sys tree and pokes the uevent files
593** to cause the kernel to regenerate device add events that happened
594** before init's device manager was started
595**
596** We drain any pending events from the netlink socket every time
597** we poke another uevent file to make sure we don't overrun the
598** socket's buffer.
599*/
600
601static void do_coldboot(int event_fd, DIR *d)
602{
603    struct dirent *de;
604    int dfd, fd;
605
606    dfd = dirfd(d);
607
608    fd = openat(dfd, "uevent", O_WRONLY);
609    if(fd >= 0) {
610        write(fd, "add\n", 4);
611        close(fd);
612        handle_device_fd(event_fd);
613    }
614
615    while((de = readdir(d))) {
616        DIR *d2;
617
618        if(de->d_type != DT_DIR || de->d_name[0] == '.')
619            continue;
620
621        fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
622        if(fd < 0)
623            continue;
624
625        d2 = fdopendir(fd);
626        if(d2 == 0)
627            close(fd);
628        else {
629            do_coldboot(event_fd, d2);
630            closedir(d2);
631        }
632    }
633}
634
635static void coldboot(int event_fd, const char *path)
636{
637    DIR *d = opendir(path);
638    if(d) {
639        do_coldboot(event_fd, d);
640        closedir(d);
641    }
642}
643
644int device_init(void)
645{
646    suseconds_t t0, t1;
647    int fd;
648
649    fd = open_uevent_socket();
650    if(fd < 0)
651        return -1;
652
653    fcntl(fd, F_SETFD, FD_CLOEXEC);
654    fcntl(fd, F_SETFL, O_NONBLOCK);
655
656    t0 = get_usecs();
657    coldboot(fd, "/sys/class");
658    coldboot(fd, "/sys/block");
659    coldboot(fd, "/sys/devices");
660    t1 = get_usecs();
661
662    log_event_print("coldboot %ld uS\n", ((long) (t1 - t0)));
663
664    return fd;
665}
666