devices.c revision eb5ba8306522acdbf3a63ca847e5e6b990d842b9 
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 <stddef.h>
19#include <stdio.h>
20#include <stdlib.h>
21#include <sys/stat.h>
22#include <sys/types.h>
23
24#include <fcntl.h>
25#include <dirent.h>
26#include <unistd.h>
27#include <string.h>
28
29#include <sys/socket.h>
30#include <sys/un.h>
31#include <linux/netlink.h>
32#include <private/android_filesystem_config.h>
33#include <sys/time.h>
34#include <asm/page.h>
35#include <sys/wait.h>
36
37#include "devices.h"
38#include "util.h"
39#include "log.h"
40#include "list.h"
41
42#define SYSFS_PREFIX    "/sys"
43#define FIRMWARE_DIR1   "/etc/firmware"
44#define FIRMWARE_DIR2   "/vendor/firmware"
45
46static int device_fd = -1;
47
48struct uevent {
49    const char *action;
50    const char *path;
51    const char *subsystem;
52    const char *firmware;
53    const char *partition_name;
54    int partition_num;
55    int major;
56    int minor;
57};
58
59static int open_uevent_socket(void)
60{
61    struct sockaddr_nl addr;
62    int sz = 64*1024; // XXX larger? udev uses 16MB!
63    int on = 1;
64    int s;
65
66    memset(&addr, 0, sizeof(addr));
67    addr.nl_family = AF_NETLINK;
68    addr.nl_pid = getpid();
69    addr.nl_groups = 0xffffffff;
70
71    s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
72    if(s < 0)
73        return -1;
74
75    setsockopt(s, SOL_SOCKET, SO_RCVBUFFORCE, &sz, sizeof(sz));
76    setsockopt(s, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
77
78    if(bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
79        close(s);
80        return -1;
81    }
82
83    return s;
84}
85
86struct perms_ {
87    char *name;
88    char *attr;
89    mode_t perm;
90    unsigned int uid;
91    unsigned int gid;
92    unsigned short prefix;
93};
94
95struct perm_node {
96    struct perms_ dp;
97    struct listnode plist;
98};
99
100static list_declare(sys_perms);
101static list_declare(dev_perms);
102
103int add_dev_perms(const char *name, const char *attr,
104                  mode_t perm, unsigned int uid, unsigned int gid,
105                  unsigned short prefix) {
106    struct perm_node *node = calloc(1, sizeof(*node));
107    if (!node)
108        return -ENOMEM;
109
110    node->dp.name = strdup(name);
111    if (!node->dp.name)
112        return -ENOMEM;
113
114    if (attr) {
115        node->dp.attr = strdup(attr);
116        if (!node->dp.attr)
117            return -ENOMEM;
118    }
119
120    node->dp.perm = perm;
121    node->dp.uid = uid;
122    node->dp.gid = gid;
123    node->dp.prefix = prefix;
124
125    if (attr)
126        list_add_tail(&sys_perms, &node->plist);
127    else
128        list_add_tail(&dev_perms, &node->plist);
129
130    return 0;
131}
132
133void fixup_sys_perms(const char *upath)
134{
135    char buf[512];
136    struct listnode *node;
137    struct perms_ *dp;
138
139        /* upaths omit the "/sys" that paths in this list
140         * contain, so we add 4 when comparing...
141         */
142    list_for_each(node, &sys_perms) {
143        dp = &(node_to_item(node, struct perm_node, plist))->dp;
144        if (dp->prefix) {
145            if (strncmp(upath, dp->name + 4, strlen(dp->name + 4)))
146                continue;
147        } else {
148            if (strcmp(upath, dp->name + 4))
149                continue;
150        }
151
152        if ((strlen(upath) + strlen(dp->attr) + 6) > sizeof(buf))
153            return;
154
155        sprintf(buf,"/sys%s/%s", upath, dp->attr);
156        INFO("fixup %s %d %d 0%o\n", buf, dp->uid, dp->gid, dp->perm);
157        chown(buf, dp->uid, dp->gid);
158        chmod(buf, dp->perm);
159    }
160}
161
162static mode_t get_device_perm(const char *path, unsigned *uid, unsigned *gid)
163{
164    mode_t perm;
165    struct listnode *node;
166    struct perm_node *perm_node;
167    struct perms_ *dp;
168
169    /* search the perms list in reverse so that ueventd.$hardware can
170     * override ueventd.rc
171     */
172    list_for_each_reverse(node, &dev_perms) {
173        perm_node = node_to_item(node, struct perm_node, plist);
174        dp = &perm_node->dp;
175
176        if (dp->prefix) {
177            if (strncmp(path, dp->name, strlen(dp->name)))
178                continue;
179        } else {
180            if (strcmp(path, dp->name))
181                continue;
182        }
183        *uid = dp->uid;
184        *gid = dp->gid;
185        return dp->perm;
186    }
187    /* Default if nothing found. */
188    *uid = 0;
189    *gid = 0;
190    return 0600;
191}
192
193static void make_device(const char *path,
194                        const char *upath,
195                        int block, int major, int minor)
196{
197    unsigned uid;
198    unsigned gid;
199    mode_t mode;
200    dev_t dev;
201
202    mode = get_device_perm(path, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
203    dev = makedev(major, minor);
204    /* Temporarily change egid to avoid race condition setting the gid of the
205     * device node. Unforunately changing the euid would prevent creation of
206     * some device nodes, so the uid has to be set with chown() and is still
207     * racy. Fixing the gid race at least fixed the issue with system_server
208     * opening dynamic input devices under the AID_INPUT gid. */
209    setegid(gid);
210    mknod(path, mode, dev);
211    chown(path, uid, -1);
212    setegid(AID_ROOT);
213}
214
215#if LOG_UEVENTS
216
217static inline suseconds_t get_usecs(void)
218{
219    struct timeval tv;
220    gettimeofday(&tv, 0);
221    return tv.tv_sec * (suseconds_t) 1000000 + tv.tv_usec;
222}
223
224#define log_event_print(x...) INFO(x)
225
226#else
227
228#define log_event_print(fmt, args...)   do { } while (0)
229#define get_usecs()                     0
230
231#endif
232
233static void parse_event(const char *msg, struct uevent *uevent)
234{
235    uevent->action = "";
236    uevent->path = "";
237    uevent->subsystem = "";
238    uevent->firmware = "";
239    uevent->major = -1;
240    uevent->minor = -1;
241    uevent->partition_name = NULL;
242    uevent->partition_num = -1;
243
244        /* currently ignoring SEQNUM */
245    while(*msg) {
246        if(!strncmp(msg, "ACTION=", 7)) {
247            msg += 7;
248            uevent->action = msg;
249        } else if(!strncmp(msg, "DEVPATH=", 8)) {
250            msg += 8;
251            uevent->path = msg;
252        } else if(!strncmp(msg, "SUBSYSTEM=", 10)) {
253            msg += 10;
254            uevent->subsystem = msg;
255        } else if(!strncmp(msg, "FIRMWARE=", 9)) {
256            msg += 9;
257            uevent->firmware = msg;
258        } else if(!strncmp(msg, "MAJOR=", 6)) {
259            msg += 6;
260            uevent->major = atoi(msg);
261        } else if(!strncmp(msg, "MINOR=", 6)) {
262            msg += 6;
263            uevent->minor = atoi(msg);
264        } else if(!strncmp(msg, "PARTN=", 6)) {
265            msg += 6;
266            uevent->partition_num = atoi(msg);
267        } else if(!strncmp(msg, "PARTNAME=", 9)) {
268            msg += 9;
269            uevent->partition_name = msg;
270        }
271
272            /* advance to after the next \0 */
273        while(*msg++)
274            ;
275    }
276
277    log_event_print("event { '%s', '%s', '%s', '%s', %d, %d }\n",
278                    uevent->action, uevent->path, uevent->subsystem,
279                    uevent->firmware, uevent->major, uevent->minor);
280}
281
282static char **get_character_device_symlinks(struct uevent *uevent)
283{
284    const char *parent;
285    char *slash;
286    char **links;
287    int link_num = 0;
288    int width;
289
290    if (strncmp(uevent->path, "/devices/platform/", 18))
291        return NULL;
292
293    links = malloc(sizeof(char *) * 2);
294    if (!links)
295        return NULL;
296    memset(links, 0, sizeof(char *) * 2);
297
298    /* skip "/devices/platform/<driver>" */
299    parent = strchr(uevent->path + 18, '/');
300    if (!*parent)
301        goto err;
302
303    if (!strncmp(parent, "/usb", 4)) {
304        /* skip root hub name and device. use device interface */
305        while (*++parent && *parent != '/');
306        if (*parent)
307            while (*++parent && *parent != '/');
308        if (!*parent)
309            goto err;
310        slash = strchr(++parent, '/');
311        if (!slash)
312            goto err;
313        width = slash - parent;
314        if (width <= 0)
315            goto err;
316
317        if (asprintf(&links[link_num], "/dev/usb/%s%.*s", uevent->subsystem, width, parent) > 0)
318            link_num++;
319        else
320            links[link_num] = NULL;
321        mkdir("/dev/usb", 0755);
322    }
323    else {
324        goto err;
325    }
326
327    return links;
328err:
329    free(links);
330    return NULL;
331}
332
333static char **parse_platform_block_device(struct uevent *uevent)
334{
335    const char *driver;
336    const char *path;
337    char *slash;
338    int width;
339    char buf[256];
340    char link_path[256];
341    int fd;
342    int link_num = 0;
343    int ret;
344    char *p;
345    unsigned int size;
346    struct stat info;
347
348    char **links = malloc(sizeof(char *) * 4);
349    if (!links)
350        return NULL;
351    memset(links, 0, sizeof(char *) * 4);
352
353    /* Drop "/devices/platform/" */
354    path = uevent->path;
355    driver = path + 18;
356    slash = strchr(driver, '/');
357    if (!slash)
358        goto err;
359    width = slash - driver;
360    if (width <= 0)
361        goto err;
362
363    snprintf(link_path, sizeof(link_path), "/dev/block/platform/%.*s",
364             width, driver);
365
366    if (uevent->partition_name) {
367        p = strdup(uevent->partition_name);
368        sanitize(p);
369        if (asprintf(&links[link_num], "%s/by-name/%s", link_path, p) > 0)
370            link_num++;
371        else
372            links[link_num] = NULL;
373        free(p);
374    }
375
376    if (uevent->partition_num >= 0) {
377        if (asprintf(&links[link_num], "%s/by-num/p%d", link_path, uevent->partition_num) > 0)
378            link_num++;
379        else
380            links[link_num] = NULL;
381    }
382
383    slash = strrchr(path, '/');
384    if (asprintf(&links[link_num], "%s/%s", link_path, slash + 1) > 0)
385        link_num++;
386    else
387        links[link_num] = NULL;
388
389    return links;
390
391err:
392    free(links);
393    return NULL;
394}
395
396static void handle_device(const char *action, const char *devpath,
397        const char *path, int block, int major, int minor, char **links)
398{
399    int i;
400
401    if(!strcmp(action, "add")) {
402        make_device(devpath, path, block, major, minor);
403        if (links) {
404            for (i = 0; links[i]; i++)
405                make_link(devpath, links[i]);
406        }
407    }
408
409    if(!strcmp(action, "remove")) {
410        if (links) {
411            for (i = 0; links[i]; i++)
412                remove_link(devpath, links[i]);
413        }
414        unlink(devpath);
415    }
416
417    if (links) {
418        for (i = 0; links[i]; i++)
419            free(links[i]);
420        free(links);
421    }
422}
423
424static const char *parse_device_name(struct uevent *uevent, unsigned int len)
425{
426    const char *name;
427
428    /* if it's not a /dev device, nothing else to do */
429    if((uevent->major < 0) || (uevent->minor < 0))
430        return NULL;
431
432    /* do we have a name? */
433    name = strrchr(uevent->path, '/');
434    if(!name)
435        return NULL;
436    name++;
437
438    /* too-long names would overrun our buffer */
439    if(strlen(name) > len)
440        return NULL;
441
442    return name;
443}
444
445static void handle_block_device_event(struct uevent *uevent)
446{
447    const char *base = "/dev/block/";
448    const char *name;
449    char devpath[96];
450    char **links = NULL;
451
452    name = parse_device_name(uevent, 64);
453    if (!name)
454        return;
455
456    snprintf(devpath, sizeof(devpath), "%s%s", base, name);
457    mkdir(base, 0755);
458
459    if (!strncmp(uevent->path, "/devices/platform/", 18))
460        links = parse_platform_block_device(uevent);
461
462    handle_device(uevent->action, devpath, uevent->path, 1,
463            uevent->major, uevent->minor, links);
464
465}
466
467static void handle_generic_device_event(struct uevent *uevent)
468{
469    char *base;
470    const char *name;
471    char devpath[96] = {0};
472    char **links = NULL;
473
474    name = parse_device_name(uevent, 64);
475    if (!name)
476        return;
477
478    if (!strncmp(uevent->subsystem, "usb", 3)) {
479         if (!strcmp(uevent->subsystem, "usb")) {
480             /* This imitates the file system that would be created
481              * if we were using devfs instead.
482              * Minors are broken up into groups of 128, starting at "001"
483              */
484             int bus_id = uevent->minor / 128 + 1;
485             int device_id = uevent->minor % 128 + 1;
486             /* build directories */
487             mkdir("/dev/bus", 0755);
488             mkdir("/dev/bus/usb", 0755);
489             snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d", bus_id);
490             mkdir(devpath, 0755);
491             snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d/%03d", bus_id, device_id);
492         } else {
493             /* ignore other USB events */
494             return;
495         }
496     } else if (!strncmp(uevent->subsystem, "graphics", 8)) {
497         base = "/dev/graphics/";
498         mkdir(base, 0755);
499     } else if (!strncmp(uevent->subsystem, "oncrpc", 6)) {
500         base = "/dev/oncrpc/";
501         mkdir(base, 0755);
502     } else if (!strncmp(uevent->subsystem, "adsp", 4)) {
503         base = "/dev/adsp/";
504         mkdir(base, 0755);
505     } else if (!strncmp(uevent->subsystem, "msm_camera", 10)) {
506         base = "/dev/msm_camera/";
507         mkdir(base, 0755);
508     } else if(!strncmp(uevent->subsystem, "input", 5)) {
509         base = "/dev/input/";
510         mkdir(base, 0755);
511     } else if(!strncmp(uevent->subsystem, "mtd", 3)) {
512         base = "/dev/mtd/";
513         mkdir(base, 0755);
514     } else if(!strncmp(uevent->subsystem, "sound", 5)) {
515         base = "/dev/snd/";
516         mkdir(base, 0755);
517     } else if(!strncmp(uevent->subsystem, "misc", 4) &&
518                 !strncmp(name, "log_", 4)) {
519         base = "/dev/log/";
520         mkdir(base, 0755);
521         name += 4;
522     } else
523         base = "/dev/";
524     links = get_character_device_symlinks(uevent);
525
526     if (!devpath[0])
527         snprintf(devpath, sizeof(devpath), "%s%s", base, name);
528
529     handle_device(uevent->action, devpath, uevent->path, 0,
530             uevent->major, uevent->minor, links);
531}
532
533static void handle_device_event(struct uevent *uevent)
534{
535    if (!strcmp(uevent->action,"add"))
536        fixup_sys_perms(uevent->path);
537
538    if (!strncmp(uevent->subsystem, "block", 5)) {
539        handle_block_device_event(uevent);
540    } else {
541        handle_generic_device_event(uevent);
542    }
543}
544
545static int load_firmware(int fw_fd, int loading_fd, int data_fd)
546{
547    struct stat st;
548    long len_to_copy;
549    int ret = 0;
550
551    if(fstat(fw_fd, &st) < 0)
552        return -1;
553    len_to_copy = st.st_size;
554
555    write(loading_fd, "1", 1);  /* start transfer */
556
557    while (len_to_copy > 0) {
558        char buf[PAGE_SIZE];
559        ssize_t nr;
560
561        nr = read(fw_fd, buf, sizeof(buf));
562        if(!nr)
563            break;
564        if(nr < 0) {
565            ret = -1;
566            break;
567        }
568
569        len_to_copy -= nr;
570        while (nr > 0) {
571            ssize_t nw = 0;
572
573            nw = write(data_fd, buf + nw, nr);
574            if(nw <= 0) {
575                ret = -1;
576                goto out;
577            }
578            nr -= nw;
579        }
580    }
581
582out:
583    if(!ret)
584        write(loading_fd, "0", 1);  /* successful end of transfer */
585    else
586        write(loading_fd, "-1", 2); /* abort transfer */
587
588    return ret;
589}
590
591static int is_booting(void)
592{
593    return access("/dev/.booting", F_OK) == 0;
594}
595
596static void process_firmware_event(struct uevent *uevent)
597{
598    char *root, *loading, *data, *file1 = NULL, *file2 = NULL;
599    int l, loading_fd, data_fd, fw_fd;
600    int booting = is_booting();
601
602    INFO("firmware: loading '%s' for '%s'\n",
603         uevent->firmware, uevent->path);
604
605    l = asprintf(&root, SYSFS_PREFIX"%s/", uevent->path);
606    if (l == -1)
607        return;
608
609    l = asprintf(&loading, "%sloading", root);
610    if (l == -1)
611        goto root_free_out;
612
613    l = asprintf(&data, "%sdata", root);
614    if (l == -1)
615        goto loading_free_out;
616
617    l = asprintf(&file1, FIRMWARE_DIR1"/%s", uevent->firmware);
618    if (l == -1)
619        goto data_free_out;
620
621    l = asprintf(&file2, FIRMWARE_DIR2"/%s", uevent->firmware);
622    if (l == -1)
623        goto data_free_out;
624
625    loading_fd = open(loading, O_WRONLY);
626    if(loading_fd < 0)
627        goto file_free_out;
628
629    data_fd = open(data, O_WRONLY);
630    if(data_fd < 0)
631        goto loading_close_out;
632
633try_loading_again:
634    fw_fd = open(file1, O_RDONLY);
635    if(fw_fd < 0) {
636        fw_fd = open(file2, O_RDONLY);
637        if (fw_fd < 0) {
638            if (booting) {
639                    /* If we're not fully booted, we may be missing
640                     * filesystems needed for firmware, wait and retry.
641                     */
642                usleep(100000);
643                booting = is_booting();
644                goto try_loading_again;
645            }
646            INFO("firmware: could not open '%s' %d\n", uevent->firmware, errno);
647            write(loading_fd, "-1", 2);
648            goto data_close_out;
649        }
650    }
651
652    if(!load_firmware(fw_fd, loading_fd, data_fd))
653        INFO("firmware: copy success { '%s', '%s' }\n", root, uevent->firmware);
654    else
655        INFO("firmware: copy failure { '%s', '%s' }\n", root, uevent->firmware);
656
657    close(fw_fd);
658data_close_out:
659    close(data_fd);
660loading_close_out:
661    close(loading_fd);
662file_free_out:
663    free(file1);
664    free(file2);
665data_free_out:
666    free(data);
667loading_free_out:
668    free(loading);
669root_free_out:
670    free(root);
671}
672
673static void handle_firmware_event(struct uevent *uevent)
674{
675    pid_t pid;
676    int ret;
677
678    if(strcmp(uevent->subsystem, "firmware"))
679        return;
680
681    if(strcmp(uevent->action, "add"))
682        return;
683
684    /* we fork, to avoid making large memory allocations in init proper */
685    pid = fork();
686    if (!pid) {
687        process_firmware_event(uevent);
688        exit(EXIT_SUCCESS);
689    }
690}
691
692#define UEVENT_MSG_LEN  1024
693void handle_device_fd()
694{
695    for(;;) {
696        char msg[UEVENT_MSG_LEN+2];
697        char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
698        struct iovec iov = {msg, sizeof(msg)};
699        struct sockaddr_nl snl;
700        struct msghdr hdr = {&snl, sizeof(snl), &iov, 1, cred_msg, sizeof(cred_msg), 0};
701
702        ssize_t n = recvmsg(device_fd, &hdr, 0);
703        if (n <= 0) {
704            break;
705        }
706
707        if ((snl.nl_groups != 1) || (snl.nl_pid != 0)) {
708            /* ignoring non-kernel netlink multicast message */
709            continue;
710        }
711
712        struct cmsghdr * cmsg = CMSG_FIRSTHDR(&hdr);
713        if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
714            /* no sender credentials received, ignore message */
715            continue;
716        }
717
718        struct ucred * cred = (struct ucred *)CMSG_DATA(cmsg);
719        if (cred->uid != 0) {
720            /* message from non-root user, ignore */
721            continue;
722        }
723
724        if(n >= UEVENT_MSG_LEN)   /* overflow -- discard */
725            continue;
726
727        msg[n] = '\0';
728        msg[n+1] = '\0';
729
730        struct uevent uevent;
731        parse_event(msg, &uevent);
732
733        handle_device_event(&uevent);
734        handle_firmware_event(&uevent);
735    }
736}
737
738/* Coldboot walks parts of the /sys tree and pokes the uevent files
739** to cause the kernel to regenerate device add events that happened
740** before init's device manager was started
741**
742** We drain any pending events from the netlink socket every time
743** we poke another uevent file to make sure we don't overrun the
744** socket's buffer.
745*/
746
747static void do_coldboot(DIR *d)
748{
749    struct dirent *de;
750    int dfd, fd;
751
752    dfd = dirfd(d);
753
754    fd = openat(dfd, "uevent", O_WRONLY);
755    if(fd >= 0) {
756        write(fd, "add\n", 4);
757        close(fd);
758        handle_device_fd();
759    }
760
761    while((de = readdir(d))) {
762        DIR *d2;
763
764        if(de->d_type != DT_DIR || de->d_name[0] == '.')
765            continue;
766
767        fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
768        if(fd < 0)
769            continue;
770
771        d2 = fdopendir(fd);
772        if(d2 == 0)
773            close(fd);
774        else {
775            do_coldboot(d2);
776            closedir(d2);
777        }
778    }
779}
780
781static void coldboot(const char *path)
782{
783    DIR *d = opendir(path);
784    if(d) {
785        do_coldboot(d);
786        closedir(d);
787    }
788}
789
790void device_init(void)
791{
792    suseconds_t t0, t1;
793    struct stat info;
794    int fd;
795
796    device_fd = open_uevent_socket();
797    if(device_fd < 0)
798        return;
799
800    fcntl(device_fd, F_SETFD, FD_CLOEXEC);
801    fcntl(device_fd, F_SETFL, O_NONBLOCK);
802
803    if (stat(coldboot_done, &info) < 0) {
804        t0 = get_usecs();
805        coldboot("/sys/class");
806        coldboot("/sys/block");
807        coldboot("/sys/devices");
808        t1 = get_usecs();
809        fd = open(coldboot_done, O_WRONLY|O_CREAT, 0000);
810        close(fd);
811        log_event_print("coldboot %ld uS\n", ((long) (t1 - t0)));
812    } else {
813        log_event_print("skipping coldboot, already done\n");
814    }
815}
816
817int get_device_fd()
818{
819    return device_fd;
820}
821