devices.c revision 53a0288463c3fd88fb7f2cfa37c0e985eb1870f4 
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
33#include <selinux/selinux.h>
34#include <selinux/label.h>
35#include <selinux/android.h>
36
37#include <private/android_filesystem_config.h>
38#include <sys/time.h>
39#include <asm/page.h>
40#include <sys/wait.h>
41
42#include <cutils/list.h>
43#include <cutils/uevent.h>
44
45#include "devices.h"
46#include "util.h"
47#include "log.h"
48
49#define SYSFS_PREFIX    "/sys"
50#define FIRMWARE_DIR1   "/etc/firmware"
51#define FIRMWARE_DIR2   "/vendor/firmware"
52#define FIRMWARE_DIR3   "/firmware/image"
53
54extern struct selabel_handle *sehandle;
55
56static int device_fd = -1;
57
58struct uevent {
59    const char *action;
60    const char *path;
61    const char *subsystem;
62    const char *firmware;
63    const char *partition_name;
64    const char *device_name;
65    int partition_num;
66    int major;
67    int minor;
68};
69
70struct perms_ {
71    char *name;
72    char *attr;
73    mode_t perm;
74    unsigned int uid;
75    unsigned int gid;
76    unsigned short prefix;
77};
78
79struct perm_node {
80    struct perms_ dp;
81    struct listnode plist;
82};
83
84struct platform_node {
85    char *name;
86    char *path;
87    int path_len;
88    struct listnode list;
89};
90
91static list_declare(sys_perms);
92static list_declare(dev_perms);
93static list_declare(platform_names);
94
95int add_dev_perms(const char *name, const char *attr,
96                  mode_t perm, unsigned int uid, unsigned int gid,
97                  unsigned short prefix) {
98    struct perm_node *node = calloc(1, sizeof(*node));
99    if (!node)
100        return -ENOMEM;
101
102    node->dp.name = strdup(name);
103    if (!node->dp.name)
104        return -ENOMEM;
105
106    if (attr) {
107        node->dp.attr = strdup(attr);
108        if (!node->dp.attr)
109            return -ENOMEM;
110    }
111
112    node->dp.perm = perm;
113    node->dp.uid = uid;
114    node->dp.gid = gid;
115    node->dp.prefix = prefix;
116
117    if (attr)
118        list_add_tail(&sys_perms, &node->plist);
119    else
120        list_add_tail(&dev_perms, &node->plist);
121
122    return 0;
123}
124
125void fixup_sys_perms(const char *upath)
126{
127    char buf[512];
128    struct listnode *node;
129    struct perms_ *dp;
130
131        /* upaths omit the "/sys" that paths in this list
132         * contain, so we add 4 when comparing...
133         */
134    list_for_each(node, &sys_perms) {
135        dp = &(node_to_item(node, struct perm_node, plist))->dp;
136        if (dp->prefix) {
137            if (strncmp(upath, dp->name + 4, strlen(dp->name + 4)))
138                continue;
139        } else {
140            if (strcmp(upath, dp->name + 4))
141                continue;
142        }
143
144        if ((strlen(upath) + strlen(dp->attr) + 6) > sizeof(buf))
145            return;
146
147        sprintf(buf,"/sys%s/%s", upath, dp->attr);
148        INFO("fixup %s %d %d 0%o\n", buf, dp->uid, dp->gid, dp->perm);
149        chown(buf, dp->uid, dp->gid);
150        chmod(buf, dp->perm);
151    }
152}
153
154static mode_t get_device_perm(const char *path, unsigned *uid, unsigned *gid)
155{
156    mode_t perm;
157    struct listnode *node;
158    struct perm_node *perm_node;
159    struct perms_ *dp;
160
161    /* search the perms list in reverse so that ueventd.$hardware can
162     * override ueventd.rc
163     */
164    list_for_each_reverse(node, &dev_perms) {
165        perm_node = node_to_item(node, struct perm_node, plist);
166        dp = &perm_node->dp;
167
168        if (dp->prefix) {
169            if (strncmp(path, dp->name, strlen(dp->name)))
170                continue;
171        } else {
172            if (strcmp(path, dp->name))
173                continue;
174        }
175        *uid = dp->uid;
176        *gid = dp->gid;
177        return dp->perm;
178    }
179    /* Default if nothing found. */
180    *uid = 0;
181    *gid = 0;
182    return 0600;
183}
184
185static void make_device(const char *path,
186                        const char *upath,
187                        int block, int major, int minor)
188{
189    unsigned uid;
190    unsigned gid;
191    mode_t mode;
192    dev_t dev;
193    char *secontext = NULL;
194
195    mode = get_device_perm(path, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
196
197    if (sehandle) {
198        selabel_lookup(sehandle, &secontext, path, mode);
199        setfscreatecon(secontext);
200    }
201
202    dev = makedev(major, minor);
203    /* Temporarily change egid to avoid race condition setting the gid of the
204     * device node. Unforunately changing the euid would prevent creation of
205     * some device nodes, so the uid has to be set with chown() and is still
206     * racy. Fixing the gid race at least fixed the issue with system_server
207     * opening dynamic input devices under the AID_INPUT gid. */
208    setegid(gid);
209    mknod(path, mode, dev);
210    chown(path, uid, -1);
211    setegid(AID_ROOT);
212
213    if (secontext) {
214        freecon(secontext);
215        setfscreatecon(NULL);
216    }
217}
218
219static void add_platform_device(const char *path)
220{
221    int path_len = strlen(path);
222    struct listnode *node;
223    struct platform_node *bus;
224    const char *name = path;
225
226    if (!strncmp(path, "/devices/", 9)) {
227        name += 9;
228        if (!strncmp(name, "platform/", 9))
229            name += 9;
230    }
231
232    list_for_each_reverse(node, &platform_names) {
233        bus = node_to_item(node, struct platform_node, list);
234        if ((bus->path_len < path_len) &&
235                (path[bus->path_len] == '/') &&
236                !strncmp(path, bus->path, bus->path_len))
237            /* subdevice of an existing platform, ignore it */
238            return;
239    }
240
241    INFO("adding platform device %s (%s)\n", name, path);
242
243    bus = calloc(1, sizeof(struct platform_node));
244    bus->path = strdup(path);
245    bus->path_len = path_len;
246    bus->name = bus->path + (name - path);
247    list_add_tail(&platform_names, &bus->list);
248}
249
250/*
251 * given a path that may start with a platform device, find the length of the
252 * platform device prefix.  If it doesn't start with a platform device, return
253 * 0.
254 */
255static struct platform_node *find_platform_device(const char *path)
256{
257    int path_len = strlen(path);
258    struct listnode *node;
259    struct platform_node *bus;
260
261    list_for_each_reverse(node, &platform_names) {
262        bus = node_to_item(node, struct platform_node, list);
263        if ((bus->path_len < path_len) &&
264                (path[bus->path_len] == '/') &&
265                !strncmp(path, bus->path, bus->path_len))
266            return bus;
267    }
268
269    return NULL;
270}
271
272static void remove_platform_device(const char *path)
273{
274    struct listnode *node;
275    struct platform_node *bus;
276
277    list_for_each_reverse(node, &platform_names) {
278        bus = node_to_item(node, struct platform_node, list);
279        if (!strcmp(path, bus->path)) {
280            INFO("removing platform device %s\n", bus->name);
281            free(bus->path);
282            list_remove(node);
283            free(bus);
284            return;
285        }
286    }
287}
288
289#if LOG_UEVENTS
290
291static inline suseconds_t get_usecs(void)
292{
293    struct timeval tv;
294    gettimeofday(&tv, 0);
295    return tv.tv_sec * (suseconds_t) 1000000 + tv.tv_usec;
296}
297
298#define log_event_print(x...) INFO(x)
299
300#else
301
302#define log_event_print(fmt, args...)   do { } while (0)
303#define get_usecs()                     0
304
305#endif
306
307static void parse_event(const char *msg, struct uevent *uevent)
308{
309    uevent->action = "";
310    uevent->path = "";
311    uevent->subsystem = "";
312    uevent->firmware = "";
313    uevent->major = -1;
314    uevent->minor = -1;
315    uevent->partition_name = NULL;
316    uevent->partition_num = -1;
317    uevent->device_name = NULL;
318
319        /* currently ignoring SEQNUM */
320    while(*msg) {
321        if(!strncmp(msg, "ACTION=", 7)) {
322            msg += 7;
323            uevent->action = msg;
324        } else if(!strncmp(msg, "DEVPATH=", 8)) {
325            msg += 8;
326            uevent->path = msg;
327        } else if(!strncmp(msg, "SUBSYSTEM=", 10)) {
328            msg += 10;
329            uevent->subsystem = msg;
330        } else if(!strncmp(msg, "FIRMWARE=", 9)) {
331            msg += 9;
332            uevent->firmware = msg;
333        } else if(!strncmp(msg, "MAJOR=", 6)) {
334            msg += 6;
335            uevent->major = atoi(msg);
336        } else if(!strncmp(msg, "MINOR=", 6)) {
337            msg += 6;
338            uevent->minor = atoi(msg);
339        } else if(!strncmp(msg, "PARTN=", 6)) {
340            msg += 6;
341            uevent->partition_num = atoi(msg);
342        } else if(!strncmp(msg, "PARTNAME=", 9)) {
343            msg += 9;
344            uevent->partition_name = msg;
345        } else if(!strncmp(msg, "DEVNAME=", 8)) {
346            msg += 8;
347            uevent->device_name = msg;
348        }
349
350        /* advance to after the next \0 */
351        while(*msg++)
352            ;
353    }
354
355    log_event_print("event { '%s', '%s', '%s', '%s', %d, %d }\n",
356                    uevent->action, uevent->path, uevent->subsystem,
357                    uevent->firmware, uevent->major, uevent->minor);
358}
359
360static char **get_character_device_symlinks(struct uevent *uevent)
361{
362    const char *parent;
363    char *slash;
364    char **links;
365    int link_num = 0;
366    int width;
367    struct platform_node *pdev;
368
369    pdev = find_platform_device(uevent->path);
370    if (!pdev)
371        return NULL;
372
373    links = malloc(sizeof(char *) * 2);
374    if (!links)
375        return NULL;
376    memset(links, 0, sizeof(char *) * 2);
377
378    /* skip "/devices/platform/<driver>" */
379    parent = strchr(uevent->path + pdev->path_len, '/');
380    if (!*parent)
381        goto err;
382
383    if (!strncmp(parent, "/usb", 4)) {
384        /* skip root hub name and device. use device interface */
385        while (*++parent && *parent != '/');
386        if (*parent)
387            while (*++parent && *parent != '/');
388        if (!*parent)
389            goto err;
390        slash = strchr(++parent, '/');
391        if (!slash)
392            goto err;
393        width = slash - parent;
394        if (width <= 0)
395            goto err;
396
397        if (asprintf(&links[link_num], "/dev/usb/%s%.*s", uevent->subsystem, width, parent) > 0)
398            link_num++;
399        else
400            links[link_num] = NULL;
401        mkdir("/dev/usb", 0755);
402    }
403    else {
404        goto err;
405    }
406
407    return links;
408err:
409    free(links);
410    return NULL;
411}
412
413static char **parse_platform_block_device(struct uevent *uevent)
414{
415    const char *device;
416    struct platform_node *pdev;
417    char *slash;
418    int width;
419    char buf[256];
420    char link_path[256];
421    int fd;
422    int link_num = 0;
423    int ret;
424    char *p;
425    unsigned int size;
426    struct stat info;
427
428    pdev = find_platform_device(uevent->path);
429    if (!pdev)
430        return NULL;
431    device = pdev->name;
432
433    char **links = malloc(sizeof(char *) * 4);
434    if (!links)
435        return NULL;
436    memset(links, 0, sizeof(char *) * 4);
437
438    INFO("found platform device %s\n", device);
439
440    snprintf(link_path, sizeof(link_path), "/dev/block/platform/%s", device);
441
442    if (uevent->partition_name) {
443        p = strdup(uevent->partition_name);
444        sanitize(p);
445        if (asprintf(&links[link_num], "%s/by-name/%s", link_path, p) > 0)
446            link_num++;
447        else
448            links[link_num] = NULL;
449        free(p);
450    }
451
452    if (uevent->partition_num >= 0) {
453        if (asprintf(&links[link_num], "%s/by-num/p%d", link_path, uevent->partition_num) > 0)
454            link_num++;
455        else
456            links[link_num] = NULL;
457    }
458
459    slash = strrchr(uevent->path, '/');
460    if (asprintf(&links[link_num], "%s/%s", link_path, slash + 1) > 0)
461        link_num++;
462    else
463        links[link_num] = NULL;
464
465    return links;
466}
467
468static void handle_device(const char *action, const char *devpath,
469        const char *path, int block, int major, int minor, char **links)
470{
471    int i;
472
473    if(!strcmp(action, "add")) {
474        make_device(devpath, path, block, major, minor);
475        if (links) {
476            for (i = 0; links[i]; i++)
477                make_link(devpath, links[i]);
478        }
479    }
480
481    if(!strcmp(action, "remove")) {
482        if (links) {
483            for (i = 0; links[i]; i++)
484                remove_link(devpath, links[i]);
485        }
486        unlink(devpath);
487    }
488
489    if (links) {
490        for (i = 0; links[i]; i++)
491            free(links[i]);
492        free(links);
493    }
494}
495
496static void handle_platform_device_event(struct uevent *uevent)
497{
498    const char *path = uevent->path;
499
500    if (!strcmp(uevent->action, "add"))
501        add_platform_device(path);
502    else if (!strcmp(uevent->action, "remove"))
503        remove_platform_device(path);
504}
505
506static const char *parse_device_name(struct uevent *uevent, unsigned int len)
507{
508    const char *name;
509
510    /* if it's not a /dev device, nothing else to do */
511    if((uevent->major < 0) || (uevent->minor < 0))
512        return NULL;
513
514    /* do we have a name? */
515    name = strrchr(uevent->path, '/');
516    if(!name)
517        return NULL;
518    name++;
519
520    /* too-long names would overrun our buffer */
521    if(strlen(name) > len)
522        return NULL;
523
524    return name;
525}
526
527static void handle_block_device_event(struct uevent *uevent)
528{
529    const char *base = "/dev/block/";
530    const char *name;
531    char devpath[96];
532    char **links = NULL;
533
534    name = parse_device_name(uevent, 64);
535    if (!name)
536        return;
537
538    snprintf(devpath, sizeof(devpath), "%s%s", base, name);
539    make_dir(base, 0755);
540
541    if (!strncmp(uevent->path, "/devices/", 9))
542        links = parse_platform_block_device(uevent);
543
544    handle_device(uevent->action, devpath, uevent->path, 1,
545            uevent->major, uevent->minor, links);
546}
547
548static void handle_generic_device_event(struct uevent *uevent)
549{
550    char *base;
551    const char *name;
552    char devpath[96] = {0};
553    char **links = NULL;
554
555    name = parse_device_name(uevent, 64);
556    if (!name)
557        return;
558
559    if (!strncmp(uevent->subsystem, "usb", 3)) {
560         if (!strcmp(uevent->subsystem, "usb")) {
561            if (uevent->device_name) {
562                /*
563                 * create device node provided by kernel if present
564                 * see drivers/base/core.c
565                 */
566                char *p = devpath;
567                snprintf(devpath, sizeof(devpath), "/dev/%s", uevent->device_name);
568                /* skip leading /dev/ */
569                p += 5;
570                /* build directories */
571                while (*p) {
572                    if (*p == '/') {
573                        *p = 0;
574                        make_dir(devpath, 0755);
575                        *p = '/';
576                    }
577                    p++;
578                }
579             }
580             else {
581                 /* This imitates the file system that would be created
582                  * if we were using devfs instead.
583                  * Minors are broken up into groups of 128, starting at "001"
584                  */
585                 int bus_id = uevent->minor / 128 + 1;
586                 int device_id = uevent->minor % 128 + 1;
587                 /* build directories */
588                 make_dir("/dev/bus", 0755);
589                 make_dir("/dev/bus/usb", 0755);
590                 snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d", bus_id);
591                 make_dir(devpath, 0755);
592                 snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d/%03d", bus_id, device_id);
593             }
594         } else {
595             /* ignore other USB events */
596             return;
597         }
598     } else if (!strncmp(uevent->subsystem, "graphics", 8)) {
599         base = "/dev/graphics/";
600         make_dir(base, 0755);
601     } else if (!strncmp(uevent->subsystem, "drm", 3)) {
602         base = "/dev/dri/";
603         make_dir(base, 0755);
604     } else if (!strncmp(uevent->subsystem, "oncrpc", 6)) {
605         base = "/dev/oncrpc/";
606         make_dir(base, 0755);
607     } else if (!strncmp(uevent->subsystem, "adsp", 4)) {
608         base = "/dev/adsp/";
609         make_dir(base, 0755);
610     } else if (!strncmp(uevent->subsystem, "msm_camera", 10)) {
611         base = "/dev/msm_camera/";
612         make_dir(base, 0755);
613     } else if(!strncmp(uevent->subsystem, "input", 5)) {
614         base = "/dev/input/";
615         make_dir(base, 0755);
616     } else if(!strncmp(uevent->subsystem, "mtd", 3)) {
617         base = "/dev/mtd/";
618         make_dir(base, 0755);
619     } else if(!strncmp(uevent->subsystem, "sound", 5)) {
620         base = "/dev/snd/";
621         make_dir(base, 0755);
622     } else if(!strncmp(uevent->subsystem, "misc", 4) &&
623                 !strncmp(name, "log_", 4)) {
624         base = "/dev/log/";
625         make_dir(base, 0755);
626         name += 4;
627     } else
628         base = "/dev/";
629     links = get_character_device_symlinks(uevent);
630
631     if (!devpath[0])
632         snprintf(devpath, sizeof(devpath), "%s%s", base, name);
633
634     handle_device(uevent->action, devpath, uevent->path, 0,
635             uevent->major, uevent->minor, links);
636}
637
638static void handle_device_event(struct uevent *uevent)
639{
640    if (!strcmp(uevent->action,"add") || !strcmp(uevent->action, "change"))
641        fixup_sys_perms(uevent->path);
642
643    if (!strncmp(uevent->subsystem, "block", 5)) {
644        handle_block_device_event(uevent);
645    } else if (!strncmp(uevent->subsystem, "platform", 8)) {
646        handle_platform_device_event(uevent);
647    } else {
648        handle_generic_device_event(uevent);
649    }
650}
651
652static int load_firmware(int fw_fd, int loading_fd, int data_fd)
653{
654    struct stat st;
655    long len_to_copy;
656    int ret = 0;
657
658    if(fstat(fw_fd, &st) < 0)
659        return -1;
660    len_to_copy = st.st_size;
661
662    write(loading_fd, "1", 1);  /* start transfer */
663
664    while (len_to_copy > 0) {
665        char buf[PAGE_SIZE];
666        ssize_t nr;
667
668        nr = read(fw_fd, buf, sizeof(buf));
669        if(!nr)
670            break;
671        if(nr < 0) {
672            ret = -1;
673            break;
674        }
675
676        len_to_copy -= nr;
677        while (nr > 0) {
678            ssize_t nw = 0;
679
680            nw = write(data_fd, buf + nw, nr);
681            if(nw <= 0) {
682                ret = -1;
683                goto out;
684            }
685            nr -= nw;
686        }
687    }
688
689out:
690    if(!ret)
691        write(loading_fd, "0", 1);  /* successful end of transfer */
692    else
693        write(loading_fd, "-1", 2); /* abort transfer */
694
695    return ret;
696}
697
698static int is_booting(void)
699{
700    return access("/dev/.booting", F_OK) == 0;
701}
702
703static void process_firmware_event(struct uevent *uevent)
704{
705    char *root, *loading, *data, *file1 = NULL, *file2 = NULL, *file3 = NULL;
706    int l, loading_fd, data_fd, fw_fd;
707    int booting = is_booting();
708
709    INFO("firmware: loading '%s' for '%s'\n",
710         uevent->firmware, uevent->path);
711
712    l = asprintf(&root, SYSFS_PREFIX"%s/", uevent->path);
713    if (l == -1)
714        return;
715
716    l = asprintf(&loading, "%sloading", root);
717    if (l == -1)
718        goto root_free_out;
719
720    l = asprintf(&data, "%sdata", root);
721    if (l == -1)
722        goto loading_free_out;
723
724    l = asprintf(&file1, FIRMWARE_DIR1"/%s", uevent->firmware);
725    if (l == -1)
726        goto data_free_out;
727
728    l = asprintf(&file2, FIRMWARE_DIR2"/%s", uevent->firmware);
729    if (l == -1)
730        goto data_free_out;
731
732    l = asprintf(&file3, FIRMWARE_DIR3"/%s", uevent->firmware);
733    if (l == -1)
734        goto data_free_out;
735
736    loading_fd = open(loading, O_WRONLY);
737    if(loading_fd < 0)
738        goto file_free_out;
739
740    data_fd = open(data, O_WRONLY);
741    if(data_fd < 0)
742        goto loading_close_out;
743
744try_loading_again:
745    fw_fd = open(file1, O_RDONLY);
746    if(fw_fd < 0) {
747        fw_fd = open(file2, O_RDONLY);
748        if (fw_fd < 0) {
749            fw_fd = open(file3, O_RDONLY);
750            if (fw_fd < 0) {
751                if (booting) {
752                        /* If we're not fully booted, we may be missing
753                         * filesystems needed for firmware, wait and retry.
754                         */
755                    usleep(100000);
756                    booting = is_booting();
757                    goto try_loading_again;
758                }
759                INFO("firmware: could not open '%s' %d\n", uevent->firmware, errno);
760                write(loading_fd, "-1", 2);
761                goto data_close_out;
762            }
763        }
764    }
765
766    if(!load_firmware(fw_fd, loading_fd, data_fd))
767        INFO("firmware: copy success { '%s', '%s' }\n", root, uevent->firmware);
768    else
769        INFO("firmware: copy failure { '%s', '%s' }\n", root, uevent->firmware);
770
771    close(fw_fd);
772data_close_out:
773    close(data_fd);
774loading_close_out:
775    close(loading_fd);
776file_free_out:
777    free(file1);
778    free(file2);
779data_free_out:
780    free(data);
781loading_free_out:
782    free(loading);
783root_free_out:
784    free(root);
785}
786
787static void handle_firmware_event(struct uevent *uevent)
788{
789    pid_t pid;
790    int ret;
791
792    if(strcmp(uevent->subsystem, "firmware"))
793        return;
794
795    if(strcmp(uevent->action, "add"))
796        return;
797
798    /* we fork, to avoid making large memory allocations in init proper */
799    pid = fork();
800    if (!pid) {
801        process_firmware_event(uevent);
802        exit(EXIT_SUCCESS);
803    }
804}
805
806#define UEVENT_MSG_LEN  1024
807void handle_device_fd()
808{
809    char msg[UEVENT_MSG_LEN+2];
810    int n;
811    while ((n = uevent_kernel_multicast_recv(device_fd, msg, UEVENT_MSG_LEN)) > 0) {
812        if(n >= UEVENT_MSG_LEN)   /* overflow -- discard */
813            continue;
814
815        msg[n] = '\0';
816        msg[n+1] = '\0';
817
818        struct uevent uevent;
819        parse_event(msg, &uevent);
820
821        handle_device_event(&uevent);
822        handle_firmware_event(&uevent);
823    }
824}
825
826/* Coldboot walks parts of the /sys tree and pokes the uevent files
827** to cause the kernel to regenerate device add events that happened
828** before init's device manager was started
829**
830** We drain any pending events from the netlink socket every time
831** we poke another uevent file to make sure we don't overrun the
832** socket's buffer.
833*/
834
835static void do_coldboot(DIR *d)
836{
837    struct dirent *de;
838    int dfd, fd;
839
840    dfd = dirfd(d);
841
842    fd = openat(dfd, "uevent", O_WRONLY);
843    if(fd >= 0) {
844        write(fd, "add\n", 4);
845        close(fd);
846        handle_device_fd();
847    }
848
849    while((de = readdir(d))) {
850        DIR *d2;
851
852        if(de->d_type != DT_DIR || de->d_name[0] == '.')
853            continue;
854
855        fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
856        if(fd < 0)
857            continue;
858
859        d2 = fdopendir(fd);
860        if(d2 == 0)
861            close(fd);
862        else {
863            do_coldboot(d2);
864            closedir(d2);
865        }
866    }
867}
868
869static void coldboot(const char *path)
870{
871    DIR *d = opendir(path);
872    if(d) {
873        do_coldboot(d);
874        closedir(d);
875    }
876}
877
878void device_init(void)
879{
880    suseconds_t t0, t1;
881    struct stat info;
882    int fd;
883
884    sehandle = NULL;
885    if (is_selinux_enabled() > 0) {
886        sehandle = selinux_android_file_context_handle();
887    }
888
889    /* is 256K enough? udev uses 16MB! */
890    device_fd = uevent_open_socket(256*1024, true);
891    if(device_fd < 0)
892        return;
893
894    fcntl(device_fd, F_SETFD, FD_CLOEXEC);
895    fcntl(device_fd, F_SETFL, O_NONBLOCK);
896
897    if (stat(coldboot_done, &info) < 0) {
898        t0 = get_usecs();
899        coldboot("/sys/class");
900        coldboot("/sys/block");
901        coldboot("/sys/devices");
902        t1 = get_usecs();
903        fd = open(coldboot_done, O_WRONLY|O_CREAT, 0000);
904        close(fd);
905        log_event_print("coldboot %ld uS\n", ((long) (t1 - t0)));
906    } else {
907        log_event_print("skipping coldboot, already done\n");
908    }
909}
910
911int get_device_fd()
912{
913    return device_fd;
914}
915