devices.c revision 57de8b8f27f887ca8084671df777a4ac199ba647 
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 <cutils/uevent.h>
38
39#include "devices.h"
40#include "util.h"
41#include "log.h"
42#include "list.h"
43
44#define SYSFS_PREFIX    "/sys"
45#define FIRMWARE_DIR1   "/etc/firmware"
46#define FIRMWARE_DIR2   "/vendor/firmware"
47
48static int device_fd = -1;
49
50struct uevent {
51    const char *action;
52    const char *path;
53    const char *subsystem;
54    const char *firmware;
55    const char *partition_name;
56    int partition_num;
57    int major;
58    int minor;
59};
60
61static int open_uevent_socket(void)
62{
63    struct sockaddr_nl addr;
64    int sz = 64*1024; // XXX larger? udev uses 16MB!
65    int on = 1;
66    int s;
67
68    memset(&addr, 0, sizeof(addr));
69    addr.nl_family = AF_NETLINK;
70    addr.nl_pid = getpid();
71    addr.nl_groups = 0xffffffff;
72
73    s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
74    if(s < 0)
75        return -1;
76
77    setsockopt(s, SOL_SOCKET, SO_RCVBUFFORCE, &sz, sizeof(sz));
78    setsockopt(s, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
79
80    if(bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
81        close(s);
82        return -1;
83    }
84
85    return s;
86}
87
88struct perms_ {
89    char *name;
90    char *attr;
91    mode_t perm;
92    unsigned int uid;
93    unsigned int gid;
94    unsigned short prefix;
95};
96
97struct perm_node {
98    struct perms_ dp;
99    struct listnode plist;
100};
101
102struct platform_node {
103    char *name;
104    int name_len;
105    struct listnode list;
106};
107
108static list_declare(sys_perms);
109static list_declare(dev_perms);
110static list_declare(platform_names);
111
112int add_dev_perms(const char *name, const char *attr,
113                  mode_t perm, unsigned int uid, unsigned int gid,
114                  unsigned short prefix) {
115    struct perm_node *node = calloc(1, sizeof(*node));
116    if (!node)
117        return -ENOMEM;
118
119    node->dp.name = strdup(name);
120    if (!node->dp.name)
121        return -ENOMEM;
122
123    if (attr) {
124        node->dp.attr = strdup(attr);
125        if (!node->dp.attr)
126            return -ENOMEM;
127    }
128
129    node->dp.perm = perm;
130    node->dp.uid = uid;
131    node->dp.gid = gid;
132    node->dp.prefix = prefix;
133
134    if (attr)
135        list_add_tail(&sys_perms, &node->plist);
136    else
137        list_add_tail(&dev_perms, &node->plist);
138
139    return 0;
140}
141
142void fixup_sys_perms(const char *upath)
143{
144    char buf[512];
145    struct listnode *node;
146    struct perms_ *dp;
147
148        /* upaths omit the "/sys" that paths in this list
149         * contain, so we add 4 when comparing...
150         */
151    list_for_each(node, &sys_perms) {
152        dp = &(node_to_item(node, struct perm_node, plist))->dp;
153        if (dp->prefix) {
154            if (strncmp(upath, dp->name + 4, strlen(dp->name + 4)))
155                continue;
156        } else {
157            if (strcmp(upath, dp->name + 4))
158                continue;
159        }
160
161        if ((strlen(upath) + strlen(dp->attr) + 6) > sizeof(buf))
162            return;
163
164        sprintf(buf,"/sys%s/%s", upath, dp->attr);
165        INFO("fixup %s %d %d 0%o\n", buf, dp->uid, dp->gid, dp->perm);
166        chown(buf, dp->uid, dp->gid);
167        chmod(buf, dp->perm);
168    }
169}
170
171static mode_t get_device_perm(const char *path, unsigned *uid, unsigned *gid)
172{
173    mode_t perm;
174    struct listnode *node;
175    struct perm_node *perm_node;
176    struct perms_ *dp;
177
178    /* search the perms list in reverse so that ueventd.$hardware can
179     * override ueventd.rc
180     */
181    list_for_each_reverse(node, &dev_perms) {
182        perm_node = node_to_item(node, struct perm_node, plist);
183        dp = &perm_node->dp;
184
185        if (dp->prefix) {
186            if (strncmp(path, dp->name, strlen(dp->name)))
187                continue;
188        } else {
189            if (strcmp(path, dp->name))
190                continue;
191        }
192        *uid = dp->uid;
193        *gid = dp->gid;
194        return dp->perm;
195    }
196    /* Default if nothing found. */
197    *uid = 0;
198    *gid = 0;
199    return 0600;
200}
201
202static void make_device(const char *path,
203                        const char *upath,
204                        int block, int major, int minor)
205{
206    unsigned uid;
207    unsigned gid;
208    mode_t mode;
209    dev_t dev;
210
211    mode = get_device_perm(path, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
212    dev = makedev(major, minor);
213    /* Temporarily change egid to avoid race condition setting the gid of the
214     * device node. Unforunately changing the euid would prevent creation of
215     * some device nodes, so the uid has to be set with chown() and is still
216     * racy. Fixing the gid race at least fixed the issue with system_server
217     * opening dynamic input devices under the AID_INPUT gid. */
218    setegid(gid);
219    mknod(path, mode, dev);
220    chown(path, uid, -1);
221    setegid(AID_ROOT);
222}
223
224static void add_platform_device(const char *name)
225{
226    int name_len = strlen(name);
227    struct listnode *node;
228    struct platform_node *bus;
229
230    list_for_each_reverse(node, &platform_names) {
231        bus = node_to_item(node, struct platform_node, list);
232        if ((bus->name_len < name_len) &&
233                (name[bus->name_len] == '/') &&
234                !strncmp(name, bus->name, bus->name_len))
235            /* subdevice of an existing platform, ignore it */
236            return;
237    }
238
239    INFO("adding platform device %s\n", name);
240
241    bus = calloc(1, sizeof(struct platform_node));
242    bus->name = strdup(name);
243    bus->name_len = name_len;
244    list_add_tail(&platform_names, &bus->list);
245}
246
247/*
248 * given a name that may start with a platform device, find the length of the
249 * platform device prefix.  If it doesn't start with a platform device, return
250 * 0.
251 */
252static const char *find_platform_device(const char *name)
253{
254    int name_len = strlen(name);
255    struct listnode *node;
256    struct platform_node *bus;
257
258    list_for_each_reverse(node, &platform_names) {
259        bus = node_to_item(node, struct platform_node, list);
260        if ((bus->name_len < name_len) &&
261                (name[bus->name_len] == '/') &&
262                !strncmp(name, bus->name, bus->name_len))
263            return bus->name;
264    }
265
266    return NULL;
267}
268
269static void remove_platform_device(const char *name)
270{
271    struct listnode *node;
272    struct platform_node *bus;
273
274    list_for_each_reverse(node, &platform_names) {
275        bus = node_to_item(node, struct platform_node, list);
276        if (!strcmp(name, bus->name)) {
277            INFO("removing platform device %s\n", name);
278            free(bus->name);
279            list_remove(node);
280            free(bus);
281            return;
282        }
283    }
284}
285
286#if 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    uevent->partition_name = NULL;
313    uevent->partition_num = -1;
314
315        /* currently ignoring SEQNUM */
316    while(*msg) {
317        if(!strncmp(msg, "ACTION=", 7)) {
318            msg += 7;
319            uevent->action = msg;
320        } else if(!strncmp(msg, "DEVPATH=", 8)) {
321            msg += 8;
322            uevent->path = msg;
323        } else if(!strncmp(msg, "SUBSYSTEM=", 10)) {
324            msg += 10;
325            uevent->subsystem = msg;
326        } else if(!strncmp(msg, "FIRMWARE=", 9)) {
327            msg += 9;
328            uevent->firmware = msg;
329        } else if(!strncmp(msg, "MAJOR=", 6)) {
330            msg += 6;
331            uevent->major = atoi(msg);
332        } else if(!strncmp(msg, "MINOR=", 6)) {
333            msg += 6;
334            uevent->minor = atoi(msg);
335        } else if(!strncmp(msg, "PARTN=", 6)) {
336            msg += 6;
337            uevent->partition_num = atoi(msg);
338        } else if(!strncmp(msg, "PARTNAME=", 9)) {
339            msg += 9;
340            uevent->partition_name = msg;
341        }
342
343            /* advance to after the next \0 */
344        while(*msg++)
345            ;
346    }
347
348    log_event_print("event { '%s', '%s', '%s', '%s', %d, %d }\n",
349                    uevent->action, uevent->path, uevent->subsystem,
350                    uevent->firmware, uevent->major, uevent->minor);
351}
352
353static char **get_character_device_symlinks(struct uevent *uevent)
354{
355    const char *parent;
356    char *slash;
357    char **links;
358    int link_num = 0;
359    int width;
360
361    if (strncmp(uevent->path, "/devices/platform/", 18))
362        return NULL;
363
364    links = malloc(sizeof(char *) * 2);
365    if (!links)
366        return NULL;
367    memset(links, 0, sizeof(char *) * 2);
368
369    /* skip "/devices/platform/<driver>" */
370    parent = strchr(uevent->path + 18, '/');
371    if (!*parent)
372        goto err;
373
374    if (!strncmp(parent, "/usb", 4)) {
375        /* skip root hub name and device. use device interface */
376        while (*++parent && *parent != '/');
377        if (*parent)
378            while (*++parent && *parent != '/');
379        if (!*parent)
380            goto err;
381        slash = strchr(++parent, '/');
382        if (!slash)
383            goto err;
384        width = slash - parent;
385        if (width <= 0)
386            goto err;
387
388        if (asprintf(&links[link_num], "/dev/usb/%s%.*s", uevent->subsystem, width, parent) > 0)
389            link_num++;
390        else
391            links[link_num] = NULL;
392        mkdir("/dev/usb", 0755);
393    }
394    else {
395        goto err;
396    }
397
398    return links;
399err:
400    free(links);
401    return NULL;
402}
403
404static char **parse_platform_block_device(struct uevent *uevent)
405{
406    const char *device;
407    const char *path;
408    char *slash;
409    int width;
410    char buf[256];
411    char link_path[256];
412    int fd;
413    int link_num = 0;
414    int ret;
415    char *p;
416    unsigned int size;
417    struct stat info;
418
419    char **links = malloc(sizeof(char *) * 4);
420    if (!links)
421        return NULL;
422    memset(links, 0, sizeof(char *) * 4);
423
424    /* Drop "/devices/platform/" */
425    path = uevent->path;
426    device = path + 18;
427    device = find_platform_device(device);
428    if (!device)
429        goto err;
430
431    INFO("found platform device %s\n", device);
432
433    snprintf(link_path, sizeof(link_path), "/dev/block/platform/%s", device);
434
435    if (uevent->partition_name) {
436        p = strdup(uevent->partition_name);
437        sanitize(p);
438        if (asprintf(&links[link_num], "%s/by-name/%s", link_path, p) > 0)
439            link_num++;
440        else
441            links[link_num] = NULL;
442        free(p);
443    }
444
445    if (uevent->partition_num >= 0) {
446        if (asprintf(&links[link_num], "%s/by-num/p%d", link_path, uevent->partition_num) > 0)
447            link_num++;
448        else
449            links[link_num] = NULL;
450    }
451
452    slash = strrchr(path, '/');
453    if (asprintf(&links[link_num], "%s/%s", link_path, slash + 1) > 0)
454        link_num++;
455    else
456        links[link_num] = NULL;
457
458    return links;
459
460err:
461    free(links);
462    return NULL;
463}
464
465static void handle_device(const char *action, const char *devpath,
466        const char *path, int block, int major, int minor, char **links)
467{
468    int i;
469
470    if(!strcmp(action, "add")) {
471        make_device(devpath, path, block, major, minor);
472        if (links) {
473            for (i = 0; links[i]; i++)
474                make_link(devpath, links[i]);
475        }
476    }
477
478    if(!strcmp(action, "remove")) {
479        if (links) {
480            for (i = 0; links[i]; i++)
481                remove_link(devpath, links[i]);
482        }
483        unlink(devpath);
484    }
485
486    if (links) {
487        for (i = 0; links[i]; i++)
488            free(links[i]);
489        free(links);
490    }
491}
492
493static void handle_platform_device_event(struct uevent *uevent)
494{
495    const char *name = uevent->path + 18; /* length of /devices/platform/ */
496
497    if (!strcmp(uevent->action, "add"))
498        add_platform_device(name);
499    else if (!strcmp(uevent->action, "remove"))
500        remove_platform_device(name);
501}
502
503static const char *parse_device_name(struct uevent *uevent, unsigned int len)
504{
505    const char *name;
506
507    /* if it's not a /dev device, nothing else to do */
508    if((uevent->major < 0) || (uevent->minor < 0))
509        return NULL;
510
511    /* do we have a name? */
512    name = strrchr(uevent->path, '/');
513    if(!name)
514        return NULL;
515    name++;
516
517    /* too-long names would overrun our buffer */
518    if(strlen(name) > len)
519        return NULL;
520
521    return name;
522}
523
524static void handle_block_device_event(struct uevent *uevent)
525{
526    const char *base = "/dev/block/";
527    const char *name;
528    char devpath[96];
529    char **links = NULL;
530
531    name = parse_device_name(uevent, 64);
532    if (!name)
533        return;
534
535    snprintf(devpath, sizeof(devpath), "%s%s", base, name);
536    mkdir(base, 0755);
537
538    if (!strncmp(uevent->path, "/devices/platform/", 18))
539        links = parse_platform_block_device(uevent);
540
541    handle_device(uevent->action, devpath, uevent->path, 1,
542            uevent->major, uevent->minor, links);
543}
544
545static void handle_generic_device_event(struct uevent *uevent)
546{
547    char *base;
548    const char *name;
549    char devpath[96] = {0};
550    char **links = NULL;
551
552    name = parse_device_name(uevent, 64);
553    if (!name)
554        return;
555
556    if (!strncmp(uevent->subsystem, "usb", 3)) {
557         if (!strcmp(uevent->subsystem, "usb")) {
558             /* This imitates the file system that would be created
559              * if we were using devfs instead.
560              * Minors are broken up into groups of 128, starting at "001"
561              */
562             int bus_id = uevent->minor / 128 + 1;
563             int device_id = uevent->minor % 128 + 1;
564             /* build directories */
565             mkdir("/dev/bus", 0755);
566             mkdir("/dev/bus/usb", 0755);
567             snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d", bus_id);
568             mkdir(devpath, 0755);
569             snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d/%03d", bus_id, device_id);
570         } else {
571             /* ignore other USB events */
572             return;
573         }
574     } else if (!strncmp(uevent->subsystem, "graphics", 8)) {
575         base = "/dev/graphics/";
576         mkdir(base, 0755);
577     } else if (!strncmp(uevent->subsystem, "oncrpc", 6)) {
578         base = "/dev/oncrpc/";
579         mkdir(base, 0755);
580     } else if (!strncmp(uevent->subsystem, "adsp", 4)) {
581         base = "/dev/adsp/";
582         mkdir(base, 0755);
583     } else if (!strncmp(uevent->subsystem, "msm_camera", 10)) {
584         base = "/dev/msm_camera/";
585         mkdir(base, 0755);
586     } else if(!strncmp(uevent->subsystem, "input", 5)) {
587         base = "/dev/input/";
588         mkdir(base, 0755);
589     } else if(!strncmp(uevent->subsystem, "mtd", 3)) {
590         base = "/dev/mtd/";
591         mkdir(base, 0755);
592     } else if(!strncmp(uevent->subsystem, "sound", 5)) {
593         base = "/dev/snd/";
594         mkdir(base, 0755);
595     } else if(!strncmp(uevent->subsystem, "misc", 4) &&
596                 !strncmp(name, "log_", 4)) {
597         base = "/dev/log/";
598         mkdir(base, 0755);
599         name += 4;
600     } else
601         base = "/dev/";
602     links = get_character_device_symlinks(uevent);
603
604     if (!devpath[0])
605         snprintf(devpath, sizeof(devpath), "%s%s", base, name);
606
607     handle_device(uevent->action, devpath, uevent->path, 0,
608             uevent->major, uevent->minor, links);
609}
610
611static void handle_device_event(struct uevent *uevent)
612{
613    if (!strcmp(uevent->action,"add"))
614        fixup_sys_perms(uevent->path);
615
616    if (!strncmp(uevent->subsystem, "block", 5)) {
617        handle_block_device_event(uevent);
618    } else if (!strncmp(uevent->subsystem, "platform", 8)) {
619        handle_platform_device_event(uevent);
620    } else {
621        handle_generic_device_event(uevent);
622    }
623}
624
625static int load_firmware(int fw_fd, int loading_fd, int data_fd)
626{
627    struct stat st;
628    long len_to_copy;
629    int ret = 0;
630
631    if(fstat(fw_fd, &st) < 0)
632        return -1;
633    len_to_copy = st.st_size;
634
635    write(loading_fd, "1", 1);  /* start transfer */
636
637    while (len_to_copy > 0) {
638        char buf[PAGE_SIZE];
639        ssize_t nr;
640
641        nr = read(fw_fd, buf, sizeof(buf));
642        if(!nr)
643            break;
644        if(nr < 0) {
645            ret = -1;
646            break;
647        }
648
649        len_to_copy -= nr;
650        while (nr > 0) {
651            ssize_t nw = 0;
652
653            nw = write(data_fd, buf + nw, nr);
654            if(nw <= 0) {
655                ret = -1;
656                goto out;
657            }
658            nr -= nw;
659        }
660    }
661
662out:
663    if(!ret)
664        write(loading_fd, "0", 1);  /* successful end of transfer */
665    else
666        write(loading_fd, "-1", 2); /* abort transfer */
667
668    return ret;
669}
670
671static int is_booting(void)
672{
673    return access("/dev/.booting", F_OK) == 0;
674}
675
676static void process_firmware_event(struct uevent *uevent)
677{
678    char *root, *loading, *data, *file1 = NULL, *file2 = NULL;
679    int l, loading_fd, data_fd, fw_fd;
680    int booting = is_booting();
681
682    INFO("firmware: loading '%s' for '%s'\n",
683         uevent->firmware, uevent->path);
684
685    l = asprintf(&root, SYSFS_PREFIX"%s/", uevent->path);
686    if (l == -1)
687        return;
688
689    l = asprintf(&loading, "%sloading", root);
690    if (l == -1)
691        goto root_free_out;
692
693    l = asprintf(&data, "%sdata", root);
694    if (l == -1)
695        goto loading_free_out;
696
697    l = asprintf(&file1, FIRMWARE_DIR1"/%s", uevent->firmware);
698    if (l == -1)
699        goto data_free_out;
700
701    l = asprintf(&file2, FIRMWARE_DIR2"/%s", uevent->firmware);
702    if (l == -1)
703        goto data_free_out;
704
705    loading_fd = open(loading, O_WRONLY);
706    if(loading_fd < 0)
707        goto file_free_out;
708
709    data_fd = open(data, O_WRONLY);
710    if(data_fd < 0)
711        goto loading_close_out;
712
713try_loading_again:
714    fw_fd = open(file1, O_RDONLY);
715    if(fw_fd < 0) {
716        fw_fd = open(file2, O_RDONLY);
717        if (fw_fd < 0) {
718            if (booting) {
719                    /* If we're not fully booted, we may be missing
720                     * filesystems needed for firmware, wait and retry.
721                     */
722                usleep(100000);
723                booting = is_booting();
724                goto try_loading_again;
725            }
726            INFO("firmware: could not open '%s' %d\n", uevent->firmware, errno);
727            write(loading_fd, "-1", 2);
728            goto data_close_out;
729        }
730    }
731
732    if(!load_firmware(fw_fd, loading_fd, data_fd))
733        INFO("firmware: copy success { '%s', '%s' }\n", root, uevent->firmware);
734    else
735        INFO("firmware: copy failure { '%s', '%s' }\n", root, uevent->firmware);
736
737    close(fw_fd);
738data_close_out:
739    close(data_fd);
740loading_close_out:
741    close(loading_fd);
742file_free_out:
743    free(file1);
744    free(file2);
745data_free_out:
746    free(data);
747loading_free_out:
748    free(loading);
749root_free_out:
750    free(root);
751}
752
753static void handle_firmware_event(struct uevent *uevent)
754{
755    pid_t pid;
756    int ret;
757
758    if(strcmp(uevent->subsystem, "firmware"))
759        return;
760
761    if(strcmp(uevent->action, "add"))
762        return;
763
764    /* we fork, to avoid making large memory allocations in init proper */
765    pid = fork();
766    if (!pid) {
767        process_firmware_event(uevent);
768        exit(EXIT_SUCCESS);
769    }
770}
771
772#define UEVENT_MSG_LEN  1024
773void handle_device_fd()
774{
775    char msg[UEVENT_MSG_LEN+2];
776    int n;
777    while ((n = uevent_kernel_multicast_recv(device_fd, msg, UEVENT_MSG_LEN)) > 0) {
778        if(n >= UEVENT_MSG_LEN)   /* overflow -- discard */
779            continue;
780
781        msg[n] = '\0';
782        msg[n+1] = '\0';
783
784        struct uevent uevent;
785        parse_event(msg, &uevent);
786
787        handle_device_event(&uevent);
788        handle_firmware_event(&uevent);
789    }
790}
791
792/* Coldboot walks parts of the /sys tree and pokes the uevent files
793** to cause the kernel to regenerate device add events that happened
794** before init's device manager was started
795**
796** We drain any pending events from the netlink socket every time
797** we poke another uevent file to make sure we don't overrun the
798** socket's buffer.
799*/
800
801static void do_coldboot(DIR *d)
802{
803    struct dirent *de;
804    int dfd, fd;
805
806    dfd = dirfd(d);
807
808    fd = openat(dfd, "uevent", O_WRONLY);
809    if(fd >= 0) {
810        write(fd, "add\n", 4);
811        close(fd);
812        handle_device_fd();
813    }
814
815    while((de = readdir(d))) {
816        DIR *d2;
817
818        if(de->d_type != DT_DIR || de->d_name[0] == '.')
819            continue;
820
821        fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
822        if(fd < 0)
823            continue;
824
825        d2 = fdopendir(fd);
826        if(d2 == 0)
827            close(fd);
828        else {
829            do_coldboot(d2);
830            closedir(d2);
831        }
832    }
833}
834
835static void coldboot(const char *path)
836{
837    DIR *d = opendir(path);
838    if(d) {
839        do_coldboot(d);
840        closedir(d);
841    }
842}
843
844void device_init(void)
845{
846    suseconds_t t0, t1;
847    struct stat info;
848    int fd;
849
850    device_fd = open_uevent_socket();
851    if(device_fd < 0)
852        return;
853
854    fcntl(device_fd, F_SETFD, FD_CLOEXEC);
855    fcntl(device_fd, F_SETFL, O_NONBLOCK);
856
857    if (stat(coldboot_done, &info) < 0) {
858        t0 = get_usecs();
859        coldboot("/sys/class");
860        coldboot("/sys/block");
861        coldboot("/sys/devices");
862        t1 = get_usecs();
863        fd = open(coldboot_done, O_WRONLY|O_CREAT, 0000);
864        close(fd);
865        log_event_print("coldboot %ld uS\n", ((long) (t1 - t0)));
866    } else {
867        log_event_print("skipping coldboot, already done\n");
868    }
869}
870
871int get_device_fd()
872{
873    return device_fd;
874}
875