devices.cpp revision dc848566a17eb62109b0e682e8c62628e420ea19 
1/*
2 * Copyright (C) 2007-2014 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 <fnmatch.h>
19#include <stddef.h>
20#include <stdio.h>
21#include <stdlib.h>
22#include <sys/stat.h>
23#include <sys/types.h>
24
25#include <fcntl.h>
26#include <dirent.h>
27#include <unistd.h>
28#include <string.h>
29
30#include <sys/socket.h>
31#include <sys/un.h>
32#include <linux/netlink.h>
33
34#include <selinux/selinux.h>
35#include <selinux/label.h>
36#include <selinux/android.h>
37#include <selinux/avc.h>
38
39#include <private/android_filesystem_config.h>
40#include <sys/time.h>
41#include <sys/wait.h>
42
43#include <android-base/file.h>
44#include <cutils/list.h>
45#include <cutils/uevent.h>
46
47#include "devices.h"
48#include "ueventd_parser.h"
49#include "util.h"
50#include "log.h"
51
52#define SYSFS_PREFIX    "/sys"
53static const char *firmware_dirs[] = { "/etc/firmware",
54                                       "/vendor/firmware",
55                                       "/firmware/image" };
56
57extern struct selabel_handle *sehandle;
58
59static int device_fd = -1;
60
61struct uevent {
62    const char *action;
63    const char *path;
64    const char *subsystem;
65    const char *firmware;
66    const char *partition_name;
67    const char *device_name;
68    int partition_num;
69    int major;
70    int minor;
71};
72
73struct perms_ {
74    char *name;
75    char *attr;
76    mode_t perm;
77    unsigned int uid;
78    unsigned int gid;
79    unsigned short prefix;
80    unsigned short wildcard;
81};
82
83struct perm_node {
84    struct perms_ dp;
85    struct listnode plist;
86};
87
88struct platform_node {
89    char *name;
90    char *path;
91    int path_len;
92    struct listnode list;
93};
94
95static list_declare(sys_perms);
96static list_declare(dev_perms);
97static list_declare(platform_names);
98
99int add_dev_perms(const char *name, const char *attr,
100                  mode_t perm, unsigned int uid, unsigned int gid,
101                  unsigned short prefix,
102                  unsigned short wildcard) {
103    struct perm_node *node = (perm_node*) calloc(1, sizeof(*node));
104    if (!node)
105        return -ENOMEM;
106
107    node->dp.name = strdup(name);
108    if (!node->dp.name)
109        return -ENOMEM;
110
111    if (attr) {
112        node->dp.attr = strdup(attr);
113        if (!node->dp.attr)
114            return -ENOMEM;
115    }
116
117    node->dp.perm = perm;
118    node->dp.uid = uid;
119    node->dp.gid = gid;
120    node->dp.prefix = prefix;
121    node->dp.wildcard = wildcard;
122
123    if (attr)
124        list_add_tail(&sys_perms, &node->plist);
125    else
126        list_add_tail(&dev_perms, &node->plist);
127
128    return 0;
129}
130
131void fixup_sys_perms(const char *upath)
132{
133    char buf[512];
134    struct listnode *node;
135    struct perms_ *dp;
136
137    /* upaths omit the "/sys" that paths in this list
138     * contain, so we add 4 when comparing...
139     */
140    list_for_each(node, &sys_perms) {
141        dp = &(node_to_item(node, struct perm_node, plist))->dp;
142        if (dp->prefix) {
143            if (strncmp(upath, dp->name + 4, strlen(dp->name + 4)))
144                continue;
145        } else if (dp->wildcard) {
146            if (fnmatch(dp->name + 4, upath, FNM_PATHNAME) != 0)
147                continue;
148        } else {
149            if (strcmp(upath, dp->name + 4))
150                continue;
151        }
152
153        if ((strlen(upath) + strlen(dp->attr) + 6) > sizeof(buf))
154            break;
155
156        snprintf(buf, sizeof(buf), "/sys%s/%s", upath, dp->attr);
157        INFO("fixup %s %d %d 0%o\n", buf, dp->uid, dp->gid, dp->perm);
158        chown(buf, dp->uid, dp->gid);
159        chmod(buf, dp->perm);
160    }
161
162    // Now fixup SELinux file labels
163    int len = snprintf(buf, sizeof(buf), "/sys%s", upath);
164    if ((len < 0) || ((size_t) len >= sizeof(buf))) {
165        // Overflow
166        return;
167    }
168    if (access(buf, F_OK) == 0) {
169        INFO("restorecon_recursive: %s\n", buf);
170        restorecon_recursive(buf);
171    }
172}
173
174static bool perm_path_matches(const char *path, struct perms_ *dp)
175{
176    if (dp->prefix) {
177        if (strncmp(path, dp->name, strlen(dp->name)) == 0)
178            return true;
179    } else if (dp->wildcard) {
180        if (fnmatch(dp->name, path, FNM_PATHNAME) == 0)
181            return true;
182    } else {
183        if (strcmp(path, dp->name) == 0)
184            return true;
185    }
186
187    return false;
188}
189
190static mode_t get_device_perm(const char *path, const char **links,
191                unsigned *uid, unsigned *gid)
192{
193    struct listnode *node;
194    struct perm_node *perm_node;
195    struct perms_ *dp;
196
197    /* search the perms list in reverse so that ueventd.$hardware can
198     * override ueventd.rc
199     */
200    list_for_each_reverse(node, &dev_perms) {
201        bool match = false;
202
203        perm_node = node_to_item(node, struct perm_node, plist);
204        dp = &perm_node->dp;
205
206        if (perm_path_matches(path, dp)) {
207            match = true;
208        } else {
209            if (links) {
210                int i;
211                for (i = 0; links[i]; i++) {
212                    if (perm_path_matches(links[i], dp)) {
213                        match = true;
214                        break;
215                    }
216                }
217            }
218        }
219
220        if (match) {
221            *uid = dp->uid;
222            *gid = dp->gid;
223            return dp->perm;
224        }
225    }
226    /* Default if nothing found. */
227    *uid = 0;
228    *gid = 0;
229    return 0600;
230}
231
232static void make_device(const char *path,
233                        const char */*upath*/,
234                        int block, int major, int minor,
235                        const char **links)
236{
237    unsigned uid;
238    unsigned gid;
239    mode_t mode;
240    dev_t dev;
241    char *secontext = NULL;
242
243    mode = get_device_perm(path, links, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
244
245    selabel_lookup_best_match(sehandle, &secontext, path, links, mode);
246    setfscreatecon(secontext);
247
248    dev = makedev(major, minor);
249    /* Temporarily change egid to avoid race condition setting the gid of the
250     * device node. Unforunately changing the euid would prevent creation of
251     * some device nodes, so the uid has to be set with chown() and is still
252     * racy. Fixing the gid race at least fixed the issue with system_server
253     * opening dynamic input devices under the AID_INPUT gid. */
254    setegid(gid);
255    mknod(path, mode, dev);
256    chown(path, uid, -1);
257    setegid(AID_ROOT);
258
259    if (secontext) {
260        freecon(secontext);
261        setfscreatecon(NULL);
262    }
263}
264
265static void add_platform_device(const char *path)
266{
267    int path_len = strlen(path);
268    struct platform_node *bus;
269    const char *name = path;
270
271    if (!strncmp(path, "/devices/", 9)) {
272        name += 9;
273        if (!strncmp(name, "platform/", 9))
274            name += 9;
275    }
276
277    INFO("adding platform device %s (%s)\n", name, path);
278
279    bus = (platform_node*) calloc(1, sizeof(struct platform_node));
280    bus->path = strdup(path);
281    bus->path_len = path_len;
282    bus->name = bus->path + (name - path);
283    list_add_tail(&platform_names, &bus->list);
284}
285
286/*
287 * given a path that may start with a platform device, find the length of the
288 * platform device prefix.  If it doesn't start with a platform device, return
289 * 0.
290 */
291static struct platform_node *find_platform_device(const char *path)
292{
293    int path_len = strlen(path);
294    struct listnode *node;
295    struct platform_node *bus;
296
297    list_for_each_reverse(node, &platform_names) {
298        bus = node_to_item(node, struct platform_node, list);
299        if ((bus->path_len < path_len) &&
300                (path[bus->path_len] == '/') &&
301                !strncmp(path, bus->path, bus->path_len))
302            return bus;
303    }
304
305    return NULL;
306}
307
308static void remove_platform_device(const char *path)
309{
310    struct listnode *node;
311    struct platform_node *bus;
312
313    list_for_each_reverse(node, &platform_names) {
314        bus = node_to_item(node, struct platform_node, list);
315        if (!strcmp(path, bus->path)) {
316            INFO("removing platform device %s\n", bus->name);
317            free(bus->path);
318            list_remove(node);
319            free(bus);
320            return;
321        }
322    }
323}
324
325/* Given a path that may start with a PCI device, populate the supplied buffer
326 * with the PCI domain/bus number and the peripheral ID and return 0.
327 * If it doesn't start with a PCI device, or there is some error, return -1 */
328static int find_pci_device_prefix(const char *path, char *buf, ssize_t buf_sz)
329{
330    const char *start, *end;
331
332    if (strncmp(path, "/devices/pci", 12))
333        return -1;
334
335    /* Beginning of the prefix is the initial "pci" after "/devices/" */
336    start = path + 9;
337
338    /* End of the prefix is two path '/' later, capturing the domain/bus number
339     * and the peripheral ID. Example: pci0000:00/0000:00:1f.2 */
340    end = strchr(start, '/');
341    if (!end)
342        return -1;
343    end = strchr(end + 1, '/');
344    if (!end)
345        return -1;
346
347    /* Make sure we have enough room for the string plus null terminator */
348    if (end - start + 1 > buf_sz)
349        return -1;
350
351    strncpy(buf, start, end - start);
352    buf[end - start] = '\0';
353    return 0;
354}
355
356static void parse_event(const char *msg, struct uevent *uevent)
357{
358    uevent->action = "";
359    uevent->path = "";
360    uevent->subsystem = "";
361    uevent->firmware = "";
362    uevent->major = -1;
363    uevent->minor = -1;
364    uevent->partition_name = NULL;
365    uevent->partition_num = -1;
366    uevent->device_name = NULL;
367
368        /* currently ignoring SEQNUM */
369    while(*msg) {
370        if(!strncmp(msg, "ACTION=", 7)) {
371            msg += 7;
372            uevent->action = msg;
373        } else if(!strncmp(msg, "DEVPATH=", 8)) {
374            msg += 8;
375            uevent->path = msg;
376        } else if(!strncmp(msg, "SUBSYSTEM=", 10)) {
377            msg += 10;
378            uevent->subsystem = msg;
379        } else if(!strncmp(msg, "FIRMWARE=", 9)) {
380            msg += 9;
381            uevent->firmware = msg;
382        } else if(!strncmp(msg, "MAJOR=", 6)) {
383            msg += 6;
384            uevent->major = atoi(msg);
385        } else if(!strncmp(msg, "MINOR=", 6)) {
386            msg += 6;
387            uevent->minor = atoi(msg);
388        } else if(!strncmp(msg, "PARTN=", 6)) {
389            msg += 6;
390            uevent->partition_num = atoi(msg);
391        } else if(!strncmp(msg, "PARTNAME=", 9)) {
392            msg += 9;
393            uevent->partition_name = msg;
394        } else if(!strncmp(msg, "DEVNAME=", 8)) {
395            msg += 8;
396            uevent->device_name = msg;
397        }
398
399        /* advance to after the next \0 */
400        while(*msg++)
401            ;
402    }
403
404    if (LOG_UEVENTS) {
405        INFO("event { '%s', '%s', '%s', '%s', %d, %d }\n",
406             uevent->action, uevent->path, uevent->subsystem,
407             uevent->firmware, uevent->major, uevent->minor);
408    }
409}
410
411static char **get_character_device_symlinks(struct uevent *uevent)
412{
413    const char *parent;
414    char *slash;
415    char **links;
416    int link_num = 0;
417    int width;
418    struct platform_node *pdev;
419
420    pdev = find_platform_device(uevent->path);
421    if (!pdev)
422        return NULL;
423
424    links = (char**) malloc(sizeof(char *) * 2);
425    if (!links)
426        return NULL;
427    memset(links, 0, sizeof(char *) * 2);
428
429    /* skip "/devices/platform/<driver>" */
430    parent = strchr(uevent->path + pdev->path_len, '/');
431    if (!parent)
432        goto err;
433
434    if (!strncmp(parent, "/usb", 4)) {
435        /* skip root hub name and device. use device interface */
436        while (*++parent && *parent != '/');
437        if (*parent)
438            while (*++parent && *parent != '/');
439        if (!*parent)
440            goto err;
441        slash = strchr(++parent, '/');
442        if (!slash)
443            goto err;
444        width = slash - parent;
445        if (width <= 0)
446            goto err;
447
448        if (asprintf(&links[link_num], "/dev/usb/%s%.*s", uevent->subsystem, width, parent) > 0)
449            link_num++;
450        else
451            links[link_num] = NULL;
452        mkdir("/dev/usb", 0755);
453    }
454    else {
455        goto err;
456    }
457
458    return links;
459err:
460    free(links);
461    return NULL;
462}
463
464static char **get_block_device_symlinks(struct uevent *uevent)
465{
466    const char *device;
467    struct platform_node *pdev;
468    char *slash;
469    const char *type;
470    char buf[256];
471    char link_path[256];
472    int link_num = 0;
473    char *p;
474
475    pdev = find_platform_device(uevent->path);
476    if (pdev) {
477        device = pdev->name;
478        type = "platform";
479    } else if (!find_pci_device_prefix(uevent->path, buf, sizeof(buf))) {
480        device = buf;
481        type = "pci";
482    } else {
483        return NULL;
484    }
485
486    char **links = (char**) malloc(sizeof(char *) * 4);
487    if (!links)
488        return NULL;
489    memset(links, 0, sizeof(char *) * 4);
490
491    INFO("found %s device %s\n", type, device);
492
493    snprintf(link_path, sizeof(link_path), "/dev/block/%s/%s", type, device);
494
495    if (uevent->partition_name) {
496        p = strdup(uevent->partition_name);
497        sanitize(p);
498        if (strcmp(uevent->partition_name, p))
499            NOTICE("Linking partition '%s' as '%s'\n", uevent->partition_name, p);
500        if (asprintf(&links[link_num], "%s/by-name/%s", link_path, p) > 0)
501            link_num++;
502        else
503            links[link_num] = NULL;
504        free(p);
505    }
506
507    if (uevent->partition_num >= 0) {
508        if (asprintf(&links[link_num], "%s/by-num/p%d", link_path, uevent->partition_num) > 0)
509            link_num++;
510        else
511            links[link_num] = NULL;
512    }
513
514    slash = strrchr(uevent->path, '/');
515    if (asprintf(&links[link_num], "%s/%s", link_path, slash + 1) > 0)
516        link_num++;
517    else
518        links[link_num] = NULL;
519
520    return links;
521}
522
523static void handle_device(const char *action, const char *devpath,
524        const char *path, int block, int major, int minor, char **links)
525{
526    int i;
527
528    if(!strcmp(action, "add")) {
529        make_device(devpath, path, block, major, minor, (const char **)links);
530        if (links) {
531            for (i = 0; links[i]; i++)
532                make_link_init(devpath, links[i]);
533        }
534    }
535
536    if(!strcmp(action, "remove")) {
537        if (links) {
538            for (i = 0; links[i]; i++)
539                remove_link(devpath, links[i]);
540        }
541        unlink(devpath);
542    }
543
544    if (links) {
545        for (i = 0; links[i]; i++)
546            free(links[i]);
547        free(links);
548    }
549}
550
551static void handle_platform_device_event(struct uevent *uevent)
552{
553    const char *path = uevent->path;
554
555    if (!strcmp(uevent->action, "add"))
556        add_platform_device(path);
557    else if (!strcmp(uevent->action, "remove"))
558        remove_platform_device(path);
559}
560
561static const char *parse_device_name(struct uevent *uevent, unsigned int len)
562{
563    const char *name;
564
565    /* if it's not a /dev device, nothing else to do */
566    if((uevent->major < 0) || (uevent->minor < 0))
567        return NULL;
568
569    /* do we have a name? */
570    name = strrchr(uevent->path, '/');
571    if(!name)
572        return NULL;
573    name++;
574
575    /* too-long names would overrun our buffer */
576    if(strlen(name) > len) {
577        ERROR("DEVPATH=%s exceeds %u-character limit on filename; ignoring event\n",
578                name, len);
579        return NULL;
580    }
581
582    return name;
583}
584
585static void handle_block_device_event(struct uevent *uevent)
586{
587    const char *base = "/dev/block/";
588    const char *name;
589    char devpath[96];
590    char **links = NULL;
591
592    name = parse_device_name(uevent, 64);
593    if (!name)
594        return;
595
596    snprintf(devpath, sizeof(devpath), "%s%s", base, name);
597    make_dir(base, 0755);
598
599    if (!strncmp(uevent->path, "/devices/", 9))
600        links = get_block_device_symlinks(uevent);
601
602    handle_device(uevent->action, devpath, uevent->path, 1,
603            uevent->major, uevent->minor, links);
604}
605
606#define DEVPATH_LEN 96
607
608static bool assemble_devpath(char *devpath, const char *dirname,
609        const char *devname)
610{
611    int s = snprintf(devpath, DEVPATH_LEN, "%s/%s", dirname, devname);
612    if (s < 0) {
613        ERROR("failed to assemble device path (%s); ignoring event\n",
614                strerror(errno));
615        return false;
616    } else if (s >= DEVPATH_LEN) {
617        ERROR("%s/%s exceeds %u-character limit on path; ignoring event\n",
618                dirname, devname, DEVPATH_LEN);
619        return false;
620    }
621    return true;
622}
623
624static void mkdir_recursive_for_devpath(const char *devpath)
625{
626    char dir[DEVPATH_LEN];
627    char *slash;
628
629    strcpy(dir, devpath);
630    slash = strrchr(dir, '/');
631    *slash = '\0';
632    mkdir_recursive(dir, 0755);
633}
634
635static void handle_generic_device_event(struct uevent *uevent)
636{
637    const char *base;
638    const char *name;
639    char devpath[DEVPATH_LEN] = {0};
640    char **links = NULL;
641
642    name = parse_device_name(uevent, 64);
643    if (!name)
644        return;
645
646    struct ueventd_subsystem *subsystem =
647            ueventd_subsystem_find_by_name(uevent->subsystem);
648
649    if (subsystem) {
650        const char *devname;
651
652        switch (subsystem->devname_src) {
653        case DEVNAME_UEVENT_DEVNAME:
654            devname = uevent->device_name;
655            break;
656
657        case DEVNAME_UEVENT_DEVPATH:
658            devname = name;
659            break;
660
661        default:
662            ERROR("%s subsystem's devpath option is not set; ignoring event\n",
663                    uevent->subsystem);
664            return;
665        }
666
667        if (!assemble_devpath(devpath, subsystem->dirname, devname))
668            return;
669        mkdir_recursive_for_devpath(devpath);
670    } else if (!strncmp(uevent->subsystem, "usb", 3)) {
671         if (!strcmp(uevent->subsystem, "usb")) {
672            if (uevent->device_name) {
673                if (!assemble_devpath(devpath, "/dev", uevent->device_name))
674                    return;
675                mkdir_recursive_for_devpath(devpath);
676             }
677             else {
678                 /* This imitates the file system that would be created
679                  * if we were using devfs instead.
680                  * Minors are broken up into groups of 128, starting at "001"
681                  */
682                 int bus_id = uevent->minor / 128 + 1;
683                 int device_id = uevent->minor % 128 + 1;
684                 /* build directories */
685                 make_dir("/dev/bus", 0755);
686                 make_dir("/dev/bus/usb", 0755);
687                 snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d", bus_id);
688                 make_dir(devpath, 0755);
689                 snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d/%03d", bus_id, device_id);
690             }
691         } else {
692             /* ignore other USB events */
693             return;
694         }
695     } else if (!strncmp(uevent->subsystem, "graphics", 8)) {
696         base = "/dev/graphics/";
697         make_dir(base, 0755);
698     } else if (!strncmp(uevent->subsystem, "drm", 3)) {
699         base = "/dev/dri/";
700         make_dir(base, 0755);
701     } else if (!strncmp(uevent->subsystem, "oncrpc", 6)) {
702         base = "/dev/oncrpc/";
703         make_dir(base, 0755);
704     } else if (!strncmp(uevent->subsystem, "adsp", 4)) {
705         base = "/dev/adsp/";
706         make_dir(base, 0755);
707     } else if (!strncmp(uevent->subsystem, "msm_camera", 10)) {
708         base = "/dev/msm_camera/";
709         make_dir(base, 0755);
710     } else if(!strncmp(uevent->subsystem, "input", 5)) {
711         base = "/dev/input/";
712         make_dir(base, 0755);
713     } else if(!strncmp(uevent->subsystem, "mtd", 3)) {
714         base = "/dev/mtd/";
715         make_dir(base, 0755);
716     } else if(!strncmp(uevent->subsystem, "sound", 5)) {
717         base = "/dev/snd/";
718         make_dir(base, 0755);
719     } else if(!strncmp(uevent->subsystem, "misc", 4) &&
720                 !strncmp(name, "log_", 4)) {
721         INFO("kernel logger is deprecated\n");
722         base = "/dev/log/";
723         make_dir(base, 0755);
724         name += 4;
725     } else
726         base = "/dev/";
727     links = get_character_device_symlinks(uevent);
728
729     if (!devpath[0])
730         snprintf(devpath, sizeof(devpath), "%s%s", base, name);
731
732     handle_device(uevent->action, devpath, uevent->path, 0,
733             uevent->major, uevent->minor, links);
734}
735
736static void handle_device_event(struct uevent *uevent)
737{
738    if (!strcmp(uevent->action,"add") || !strcmp(uevent->action, "change") || !strcmp(uevent->action, "online"))
739        fixup_sys_perms(uevent->path);
740
741    if (!strncmp(uevent->subsystem, "block", 5)) {
742        handle_block_device_event(uevent);
743    } else if (!strncmp(uevent->subsystem, "platform", 8)) {
744        handle_platform_device_event(uevent);
745    } else {
746        handle_generic_device_event(uevent);
747    }
748}
749
750static int load_firmware(int fw_fd, int loading_fd, int data_fd)
751{
752    struct stat st;
753    long len_to_copy;
754    int ret = 0;
755
756    if(fstat(fw_fd, &st) < 0)
757        return -1;
758    len_to_copy = st.st_size;
759
760    write(loading_fd, "1", 1);  /* start transfer */
761
762    while (len_to_copy > 0) {
763        char buf[PAGE_SIZE];
764        ssize_t nr;
765
766        nr = read(fw_fd, buf, sizeof(buf));
767        if(!nr)
768            break;
769        if(nr < 0) {
770            ret = -1;
771            break;
772        }
773        if (!android::base::WriteFully(data_fd, buf, nr)) {
774            ret = -1;
775            break;
776        }
777        len_to_copy -= nr;
778    }
779
780    if(!ret)
781        write(loading_fd, "0", 1);  /* successful end of transfer */
782    else
783        write(loading_fd, "-1", 2); /* abort transfer */
784
785    return ret;
786}
787
788static int is_booting(void)
789{
790    return access("/dev/.booting", F_OK) == 0;
791}
792
793static void process_firmware_event(struct uevent *uevent)
794{
795    char *root, *loading, *data;
796    int l, loading_fd, data_fd, fw_fd;
797    size_t i;
798    int booting = is_booting();
799
800    INFO("firmware: loading '%s' for '%s'\n",
801         uevent->firmware, uevent->path);
802
803    l = asprintf(&root, SYSFS_PREFIX"%s/", uevent->path);
804    if (l == -1)
805        return;
806
807    l = asprintf(&loading, "%sloading", root);
808    if (l == -1)
809        goto root_free_out;
810
811    l = asprintf(&data, "%sdata", root);
812    if (l == -1)
813        goto loading_free_out;
814
815    loading_fd = open(loading, O_WRONLY|O_CLOEXEC);
816    if(loading_fd < 0)
817        goto data_free_out;
818
819    data_fd = open(data, O_WRONLY|O_CLOEXEC);
820    if(data_fd < 0)
821        goto loading_close_out;
822
823try_loading_again:
824    for (i = 0; i < ARRAY_SIZE(firmware_dirs); i++) {
825        char *file = NULL;
826        l = asprintf(&file, "%s/%s", firmware_dirs[i], uevent->firmware);
827        if (l == -1)
828            goto data_free_out;
829        fw_fd = open(file, O_RDONLY|O_CLOEXEC);
830        free(file);
831        if (fw_fd >= 0) {
832            if(!load_firmware(fw_fd, loading_fd, data_fd))
833                INFO("firmware: copy success { '%s', '%s' }\n", root, uevent->firmware);
834            else
835                INFO("firmware: copy failure { '%s', '%s' }\n", root, uevent->firmware);
836            break;
837        }
838    }
839    if (fw_fd < 0) {
840        if (booting) {
841            /* If we're not fully booted, we may be missing
842             * filesystems needed for firmware, wait and retry.
843             */
844            usleep(100000);
845            booting = is_booting();
846            goto try_loading_again;
847        }
848        INFO("firmware: could not open '%s': %s\n", uevent->firmware, strerror(errno));
849        write(loading_fd, "-1", 2);
850        goto data_close_out;
851    }
852
853    close(fw_fd);
854data_close_out:
855    close(data_fd);
856loading_close_out:
857    close(loading_fd);
858data_free_out:
859    free(data);
860loading_free_out:
861    free(loading);
862root_free_out:
863    free(root);
864}
865
866static void handle_firmware_event(struct uevent *uevent)
867{
868    pid_t pid;
869
870    if(strcmp(uevent->subsystem, "firmware"))
871        return;
872
873    if(strcmp(uevent->action, "add"))
874        return;
875
876    /* we fork, to avoid making large memory allocations in init proper */
877    pid = fork();
878    if (!pid) {
879        process_firmware_event(uevent);
880        _exit(EXIT_SUCCESS);
881    } else if (pid < 0) {
882        ERROR("could not fork to process firmware event: %s\n", strerror(errno));
883    }
884}
885
886#define UEVENT_MSG_LEN  2048
887void handle_device_fd()
888{
889    char msg[UEVENT_MSG_LEN+2];
890    int n;
891    while ((n = uevent_kernel_multicast_recv(device_fd, msg, UEVENT_MSG_LEN)) > 0) {
892        if(n >= UEVENT_MSG_LEN)   /* overflow -- discard */
893            continue;
894
895        msg[n] = '\0';
896        msg[n+1] = '\0';
897
898        struct uevent uevent;
899        parse_event(msg, &uevent);
900
901        if (selinux_status_updated() > 0) {
902            struct selabel_handle *sehandle2;
903            sehandle2 = selinux_android_file_context_handle();
904            if (sehandle2) {
905                selabel_close(sehandle);
906                sehandle = sehandle2;
907            }
908        }
909
910        handle_device_event(&uevent);
911        handle_firmware_event(&uevent);
912    }
913}
914
915/* Coldboot walks parts of the /sys tree and pokes the uevent files
916** to cause the kernel to regenerate device add events that happened
917** before init's device manager was started
918**
919** We drain any pending events from the netlink socket every time
920** we poke another uevent file to make sure we don't overrun the
921** socket's buffer.
922*/
923
924static void do_coldboot(DIR *d)
925{
926    struct dirent *de;
927    int dfd, fd;
928
929    dfd = dirfd(d);
930
931    fd = openat(dfd, "uevent", O_WRONLY);
932    if(fd >= 0) {
933        write(fd, "add\n", 4);
934        close(fd);
935        handle_device_fd();
936    }
937
938    while((de = readdir(d))) {
939        DIR *d2;
940
941        if(de->d_type != DT_DIR || de->d_name[0] == '.')
942            continue;
943
944        fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
945        if(fd < 0)
946            continue;
947
948        d2 = fdopendir(fd);
949        if(d2 == 0)
950            close(fd);
951        else {
952            do_coldboot(d2);
953            closedir(d2);
954        }
955    }
956}
957
958static void coldboot(const char *path)
959{
960    DIR *d = opendir(path);
961    if(d) {
962        do_coldboot(d);
963        closedir(d);
964    }
965}
966
967void device_init() {
968    sehandle = selinux_android_file_context_handle();
969    selinux_status_open(true);
970
971    /* is 256K enough? udev uses 16MB! */
972    device_fd = uevent_open_socket(256*1024, true);
973    if (device_fd == -1) {
974        return;
975    }
976    fcntl(device_fd, F_SETFL, O_NONBLOCK);
977
978    if (access(COLDBOOT_DONE, F_OK) == 0) {
979        NOTICE("Skipping coldboot, already done!\n");
980        return;
981    }
982
983    Timer t;
984    coldboot("/sys/class");
985    coldboot("/sys/block");
986    coldboot("/sys/devices");
987    close(open(COLDBOOT_DONE, O_WRONLY|O_CREAT|O_CLOEXEC, 0000));
988    NOTICE("Coldboot took %.2fs.\n", t.duration());
989}
990
991int get_device_fd()
992{
993    return device_fd;
994}
995