devices.cpp revision 7eed474db429e88bcc6808a438ccc2cb18e210f6 
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 <memory>
35
36#include <selinux/selinux.h>
37#include <selinux/label.h>
38#include <selinux/android.h>
39#include <selinux/avc.h>
40
41#include <private/android_filesystem_config.h>
42#include <sys/time.h>
43#include <sys/wait.h>
44
45#include <android-base/file.h>
46#include <android-base/stringprintf.h>
47#include <cutils/list.h>
48#include <cutils/uevent.h>
49
50#include "devices.h"
51#include "ueventd_parser.h"
52#include "util.h"
53#include "log.h"
54
55#define SYSFS_PREFIX    "/sys"
56static const char *firmware_dirs[] = { "/etc/firmware",
57                                       "/vendor/firmware",
58                                       "/firmware/image" };
59
60extern struct selabel_handle *sehandle;
61
62static int device_fd = -1;
63
64struct uevent {
65    const char *action;
66    const char *path;
67    const char *subsystem;
68    const char *firmware;
69    const char *partition_name;
70    const char *device_name;
71    int partition_num;
72    int major;
73    int minor;
74};
75
76struct perms_ {
77    char *name;
78    char *attr;
79    mode_t perm;
80    unsigned int uid;
81    unsigned int gid;
82    unsigned short prefix;
83    unsigned short wildcard;
84};
85
86struct perm_node {
87    struct perms_ dp;
88    struct listnode plist;
89};
90
91struct platform_node {
92    char *name;
93    char *path;
94    int path_len;
95    struct listnode list;
96};
97
98static list_declare(sys_perms);
99static list_declare(dev_perms);
100static list_declare(platform_names);
101
102int add_dev_perms(const char *name, const char *attr,
103                  mode_t perm, unsigned int uid, unsigned int gid,
104                  unsigned short prefix,
105                  unsigned short wildcard) {
106    struct perm_node *node = (perm_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    node->dp.wildcard = wildcard;
125
126    if (attr)
127        list_add_tail(&sys_perms, &node->plist);
128    else
129        list_add_tail(&dev_perms, &node->plist);
130
131    return 0;
132}
133
134static bool perm_path_matches(const char *path, struct perms_ *dp)
135{
136    if (dp->prefix) {
137        if (strncmp(path, dp->name, strlen(dp->name)) == 0)
138            return true;
139    } else if (dp->wildcard) {
140        if (fnmatch(dp->name, path, FNM_PATHNAME) == 0)
141            return true;
142    } else {
143        if (strcmp(path, dp->name) == 0)
144            return true;
145    }
146
147    return false;
148}
149
150static bool match_subsystem(perms_* dp, const char* pattern,
151                            const char* path, const char* subsystem) {
152    if (!pattern || !subsystem || strstr(dp->name, subsystem) == NULL) {
153        return false;
154    }
155
156    std::string subsys_path = android::base::StringPrintf(pattern, subsystem, basename(path));
157    return perm_path_matches(subsys_path.c_str(), dp);
158}
159
160static void fixup_sys_perms(const char* upath, const char* subsystem) {
161    // upaths omit the "/sys" that paths in this list
162    // contain, so we prepend it...
163    std::string path = std::string(SYSFS_PREFIX) + upath;
164
165    listnode* node;
166    list_for_each(node, &sys_perms) {
167        perms_* dp = &(node_to_item(node, perm_node, plist))->dp;
168        if (match_subsystem(dp, SYSFS_PREFIX "/class/%s/%s", path.c_str(), subsystem)) {
169            ; // matched
170        } else if (match_subsystem(dp, SYSFS_PREFIX "/bus/%s/devices/%s", path.c_str(), subsystem)) {
171            ; // matched
172        } else if (!perm_path_matches(path.c_str(), dp)) {
173            continue;
174        }
175
176        std::string attr_file = path + "/" + dp->attr;
177        LOG(INFO) << "fixup " << attr_file
178                  << " " << dp->uid << " " << dp->gid << " " << std::oct << dp->perm;
179        chown(attr_file.c_str(), dp->uid, dp->gid);
180        chmod(attr_file.c_str(), dp->perm);
181    }
182
183    if (access(path.c_str(), F_OK) == 0) {
184        LOG(VERBOSE) << "restorecon_recursive: " << path;
185        restorecon_recursive(path.c_str());
186    }
187}
188
189static mode_t get_device_perm(const char *path, const char **links,
190                unsigned *uid, unsigned *gid)
191{
192    struct listnode *node;
193    struct perm_node *perm_node;
194    struct perms_ *dp;
195
196    /* search the perms list in reverse so that ueventd.$hardware can
197     * override ueventd.rc
198     */
199    list_for_each_reverse(node, &dev_perms) {
200        bool match = false;
201
202        perm_node = node_to_item(node, struct perm_node, plist);
203        dp = &perm_node->dp;
204
205        if (perm_path_matches(path, dp)) {
206            match = true;
207        } else {
208            if (links) {
209                int i;
210                for (i = 0; links[i]; i++) {
211                    if (perm_path_matches(links[i], dp)) {
212                        match = true;
213                        break;
214                    }
215                }
216            }
217        }
218
219        if (match) {
220            *uid = dp->uid;
221            *gid = dp->gid;
222            return dp->perm;
223        }
224    }
225    /* Default if nothing found. */
226    *uid = 0;
227    *gid = 0;
228    return 0600;
229}
230
231static void make_device(const char *path,
232                        const char */*upath*/,
233                        int block, int major, int minor,
234                        const char **links)
235{
236    unsigned uid;
237    unsigned gid;
238    mode_t mode;
239    dev_t dev;
240    char *secontext = NULL;
241
242    mode = get_device_perm(path, links, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
243
244    if (selabel_lookup_best_match(sehandle, &secontext, path, links, mode)) {
245        PLOG(ERROR) << "Device '" << path << "' not created; cannot find SELinux label";
246        return;
247    }
248    setfscreatecon(secontext);
249
250    dev = makedev(major, minor);
251    /* Temporarily change egid to avoid race condition setting the gid of the
252     * device node. Unforunately changing the euid would prevent creation of
253     * some device nodes, so the uid has to be set with chown() and is still
254     * racy. Fixing the gid race at least fixed the issue with system_server
255     * opening dynamic input devices under the AID_INPUT gid. */
256    setegid(gid);
257    /* If the node already exists update its SELinux label to handle cases when
258     * it was created with the wrong context during coldboot procedure. */
259    if (mknod(path, mode, dev) && (errno == EEXIST)) {
260
261        char* fcon = nullptr;
262        int rc = lgetfilecon(path, &fcon);
263        if (rc < 0) {
264            PLOG(ERROR) << "Cannot get SELinux label on '" << path << "' device";
265            goto out;
266        }
267
268        bool different = strcmp(fcon, secontext) != 0;
269        freecon(fcon);
270
271        if (different && lsetfilecon(path, secontext)) {
272            PLOG(ERROR) << "Cannot set '" << secontext << "' SELinux label on '" << path << "' device";
273        }
274    }
275
276out:
277    chown(path, uid, -1);
278    setegid(AID_ROOT);
279
280    freecon(secontext);
281    setfscreatecon(NULL);
282}
283
284static void add_platform_device(const char *path)
285{
286    int path_len = strlen(path);
287    struct platform_node *bus;
288    const char *name = path;
289
290    if (!strncmp(path, "/devices/", 9)) {
291        name += 9;
292        if (!strncmp(name, "platform/", 9))
293            name += 9;
294    }
295
296    LOG(INFO) << "adding platform device " << name << " (" << path << ")";
297
298    bus = (platform_node*) calloc(1, sizeof(struct platform_node));
299    bus->path = strdup(path);
300    bus->path_len = path_len;
301    bus->name = bus->path + (name - path);
302    list_add_tail(&platform_names, &bus->list);
303}
304
305/*
306 * given a path that may start with a platform device, find the length of the
307 * platform device prefix.  If it doesn't start with a platform device, return
308 * 0.
309 */
310static struct platform_node *find_platform_device(const char *path)
311{
312    int path_len = strlen(path);
313    struct listnode *node;
314    struct platform_node *bus;
315
316    list_for_each_reverse(node, &platform_names) {
317        bus = node_to_item(node, struct platform_node, list);
318        if ((bus->path_len < path_len) &&
319                (path[bus->path_len] == '/') &&
320                !strncmp(path, bus->path, bus->path_len))
321            return bus;
322    }
323
324    return NULL;
325}
326
327static void remove_platform_device(const char *path)
328{
329    struct listnode *node;
330    struct platform_node *bus;
331
332    list_for_each_reverse(node, &platform_names) {
333        bus = node_to_item(node, struct platform_node, list);
334        if (!strcmp(path, bus->path)) {
335            LOG(INFO) << "removing platform device " << bus->name;
336            free(bus->path);
337            list_remove(node);
338            free(bus);
339            return;
340        }
341    }
342}
343
344/* Given a path that may start with a PCI device, populate the supplied buffer
345 * with the PCI domain/bus number and the peripheral ID and return 0.
346 * If it doesn't start with a PCI device, or there is some error, return -1 */
347static int find_pci_device_prefix(const char *path, char *buf, ssize_t buf_sz)
348{
349    const char *start, *end;
350
351    if (strncmp(path, "/devices/pci", 12))
352        return -1;
353
354    /* Beginning of the prefix is the initial "pci" after "/devices/" */
355    start = path + 9;
356
357    /* End of the prefix is two path '/' later, capturing the domain/bus number
358     * and the peripheral ID. Example: pci0000:00/0000:00:1f.2 */
359    end = strchr(start, '/');
360    if (!end)
361        return -1;
362    end = strchr(end + 1, '/');
363    if (!end)
364        return -1;
365
366    /* Make sure we have enough room for the string plus null terminator */
367    if (end - start + 1 > buf_sz)
368        return -1;
369
370    strncpy(buf, start, end - start);
371    buf[end - start] = '\0';
372    return 0;
373}
374
375static void parse_event(const char *msg, struct uevent *uevent)
376{
377    uevent->action = "";
378    uevent->path = "";
379    uevent->subsystem = "";
380    uevent->firmware = "";
381    uevent->major = -1;
382    uevent->minor = -1;
383    uevent->partition_name = NULL;
384    uevent->partition_num = -1;
385    uevent->device_name = NULL;
386
387        /* currently ignoring SEQNUM */
388    while(*msg) {
389        if(!strncmp(msg, "ACTION=", 7)) {
390            msg += 7;
391            uevent->action = msg;
392        } else if(!strncmp(msg, "DEVPATH=", 8)) {
393            msg += 8;
394            uevent->path = msg;
395        } else if(!strncmp(msg, "SUBSYSTEM=", 10)) {
396            msg += 10;
397            uevent->subsystem = msg;
398        } else if(!strncmp(msg, "FIRMWARE=", 9)) {
399            msg += 9;
400            uevent->firmware = msg;
401        } else if(!strncmp(msg, "MAJOR=", 6)) {
402            msg += 6;
403            uevent->major = atoi(msg);
404        } else if(!strncmp(msg, "MINOR=", 6)) {
405            msg += 6;
406            uevent->minor = atoi(msg);
407        } else if(!strncmp(msg, "PARTN=", 6)) {
408            msg += 6;
409            uevent->partition_num = atoi(msg);
410        } else if(!strncmp(msg, "PARTNAME=", 9)) {
411            msg += 9;
412            uevent->partition_name = msg;
413        } else if(!strncmp(msg, "DEVNAME=", 8)) {
414            msg += 8;
415            uevent->device_name = msg;
416        }
417
418        /* advance to after the next \0 */
419        while(*msg++)
420            ;
421    }
422
423    if (LOG_UEVENTS) {
424        LOG(INFO) << android::base::StringPrintf("event { '%s', '%s', '%s', '%s', %d, %d }",
425                                                 uevent->action, uevent->path, uevent->subsystem,
426                                                 uevent->firmware, uevent->major, uevent->minor);
427    }
428}
429
430static char **get_character_device_symlinks(struct uevent *uevent)
431{
432    const char *parent;
433    const char *slash;
434    char **links;
435    int link_num = 0;
436    int width;
437    struct platform_node *pdev;
438
439    pdev = find_platform_device(uevent->path);
440    if (!pdev)
441        return NULL;
442
443    links = (char**) malloc(sizeof(char *) * 2);
444    if (!links)
445        return NULL;
446    memset(links, 0, sizeof(char *) * 2);
447
448    /* skip "/devices/platform/<driver>" */
449    parent = strchr(uevent->path + pdev->path_len, '/');
450    if (!parent)
451        goto err;
452
453    if (!strncmp(parent, "/usb", 4)) {
454        /* skip root hub name and device. use device interface */
455        while (*++parent && *parent != '/');
456        if (*parent)
457            while (*++parent && *parent != '/');
458        if (!*parent)
459            goto err;
460        slash = strchr(++parent, '/');
461        if (!slash)
462            goto err;
463        width = slash - parent;
464        if (width <= 0)
465            goto err;
466
467        if (asprintf(&links[link_num], "/dev/usb/%s%.*s", uevent->subsystem, width, parent) > 0)
468            link_num++;
469        else
470            links[link_num] = NULL;
471        mkdir("/dev/usb", 0755);
472    }
473    else {
474        goto err;
475    }
476
477    return links;
478err:
479    free(links);
480    return NULL;
481}
482
483static char **get_block_device_symlinks(struct uevent *uevent)
484{
485    const char *device;
486    struct platform_node *pdev;
487    const char *slash;
488    const char *type;
489    char buf[256];
490    char link_path[256];
491    int link_num = 0;
492    char *p;
493
494    pdev = find_platform_device(uevent->path);
495    if (pdev) {
496        device = pdev->name;
497        type = "platform";
498    } else if (!find_pci_device_prefix(uevent->path, buf, sizeof(buf))) {
499        device = buf;
500        type = "pci";
501    } else {
502        return NULL;
503    }
504
505    char **links = (char**) malloc(sizeof(char *) * 4);
506    if (!links)
507        return NULL;
508    memset(links, 0, sizeof(char *) * 4);
509
510    LOG(INFO) << "found " << type << " device " << device;
511
512    snprintf(link_path, sizeof(link_path), "/dev/block/%s/%s", type, device);
513
514    if (uevent->partition_name) {
515        p = strdup(uevent->partition_name);
516        sanitize(p);
517        if (strcmp(uevent->partition_name, p)) {
518            LOG(VERBOSE) << "Linking partition '" << uevent->partition_name << "' as '" << p << "'";
519        }
520        if (asprintf(&links[link_num], "%s/by-name/%s", link_path, p) > 0)
521            link_num++;
522        else
523            links[link_num] = NULL;
524        free(p);
525    }
526
527    if (uevent->partition_num >= 0) {
528        if (asprintf(&links[link_num], "%s/by-num/p%d", link_path, uevent->partition_num) > 0)
529            link_num++;
530        else
531            links[link_num] = NULL;
532    }
533
534    slash = strrchr(uevent->path, '/');
535    if (asprintf(&links[link_num], "%s/%s", link_path, slash + 1) > 0)
536        link_num++;
537    else
538        links[link_num] = NULL;
539
540    return links;
541}
542
543static void handle_device(const char *action, const char *devpath,
544        const char *path, int block, int major, int minor, char **links)
545{
546    int i;
547
548    if(!strcmp(action, "add")) {
549        make_device(devpath, path, block, major, minor, (const char **)links);
550        if (links) {
551            for (i = 0; links[i]; i++)
552                make_link_init(devpath, links[i]);
553        }
554    }
555
556    if(!strcmp(action, "remove")) {
557        if (links) {
558            for (i = 0; links[i]; i++)
559                remove_link(devpath, links[i]);
560        }
561        unlink(devpath);
562    }
563
564    if (links) {
565        for (i = 0; links[i]; i++)
566            free(links[i]);
567        free(links);
568    }
569}
570
571static void handle_platform_device_event(struct uevent *uevent)
572{
573    const char *path = uevent->path;
574
575    if (!strcmp(uevent->action, "add"))
576        add_platform_device(path);
577    else if (!strcmp(uevent->action, "remove"))
578        remove_platform_device(path);
579}
580
581static const char *parse_device_name(struct uevent *uevent, unsigned int len)
582{
583    const char *name;
584
585    /* if it's not a /dev device, nothing else to do */
586    if((uevent->major < 0) || (uevent->minor < 0))
587        return NULL;
588
589    /* do we have a name? */
590    name = strrchr(uevent->path, '/');
591    if(!name)
592        return NULL;
593    name++;
594
595    /* too-long names would overrun our buffer */
596    if(strlen(name) > len) {
597        LOG(ERROR) << "DEVPATH=" << name << " exceeds " << len << "-character limit on filename; ignoring event";
598        return NULL;
599    }
600
601    return name;
602}
603
604static void handle_block_device_event(struct uevent *uevent)
605{
606    const char *base = "/dev/block/";
607    const char *name;
608    char devpath[96];
609    char **links = NULL;
610
611    name = parse_device_name(uevent, 64);
612    if (!name)
613        return;
614
615    snprintf(devpath, sizeof(devpath), "%s%s", base, name);
616    make_dir(base, 0755);
617
618    if (!strncmp(uevent->path, "/devices/", 9))
619        links = get_block_device_symlinks(uevent);
620
621    handle_device(uevent->action, devpath, uevent->path, 1,
622            uevent->major, uevent->minor, links);
623}
624
625#define DEVPATH_LEN 96
626
627static bool assemble_devpath(char *devpath, const char *dirname,
628        const char *devname)
629{
630    int s = snprintf(devpath, DEVPATH_LEN, "%s/%s", dirname, devname);
631    if (s < 0) {
632        PLOG(ERROR) << "failed to assemble device path; ignoring event";
633        return false;
634    } else if (s >= DEVPATH_LEN) {
635        LOG(ERROR) << dirname << "/" << devname
636                   << " exceeds " << DEVPATH_LEN << "-character limit on path; ignoring event";
637        return false;
638    }
639    return true;
640}
641
642static void mkdir_recursive_for_devpath(const char *devpath)
643{
644    char dir[DEVPATH_LEN];
645    char *slash;
646
647    strcpy(dir, devpath);
648    slash = strrchr(dir, '/');
649    *slash = '\0';
650    mkdir_recursive(dir, 0755);
651}
652
653static void handle_generic_device_event(struct uevent *uevent)
654{
655    const char *base;
656    const char *name;
657    char devpath[DEVPATH_LEN] = {0};
658    char **links = NULL;
659
660    name = parse_device_name(uevent, 64);
661    if (!name)
662        return;
663
664    struct ueventd_subsystem *subsystem =
665            ueventd_subsystem_find_by_name(uevent->subsystem);
666
667    if (subsystem) {
668        const char *devname;
669
670        switch (subsystem->devname_src) {
671        case DEVNAME_UEVENT_DEVNAME:
672            devname = uevent->device_name;
673            break;
674
675        case DEVNAME_UEVENT_DEVPATH:
676            devname = name;
677            break;
678
679        default:
680            LOG(ERROR) << uevent->subsystem << " subsystem's devpath option is not set; ignoring event";
681            return;
682        }
683
684        if (!assemble_devpath(devpath, subsystem->dirname, devname))
685            return;
686        mkdir_recursive_for_devpath(devpath);
687    } else if (!strncmp(uevent->subsystem, "usb", 3)) {
688         if (!strcmp(uevent->subsystem, "usb")) {
689            if (uevent->device_name) {
690                if (!assemble_devpath(devpath, "/dev", uevent->device_name))
691                    return;
692                mkdir_recursive_for_devpath(devpath);
693             }
694             else {
695                 /* This imitates the file system that would be created
696                  * if we were using devfs instead.
697                  * Minors are broken up into groups of 128, starting at "001"
698                  */
699                 int bus_id = uevent->minor / 128 + 1;
700                 int device_id = uevent->minor % 128 + 1;
701                 /* build directories */
702                 make_dir("/dev/bus", 0755);
703                 make_dir("/dev/bus/usb", 0755);
704                 snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d", bus_id);
705                 make_dir(devpath, 0755);
706                 snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d/%03d", bus_id, device_id);
707             }
708         } else {
709             /* ignore other USB events */
710             return;
711         }
712     } else if (!strncmp(uevent->subsystem, "graphics", 8)) {
713         base = "/dev/graphics/";
714         make_dir(base, 0755);
715     } else if (!strncmp(uevent->subsystem, "drm", 3)) {
716         base = "/dev/dri/";
717         make_dir(base, 0755);
718     } else if (!strncmp(uevent->subsystem, "oncrpc", 6)) {
719         base = "/dev/oncrpc/";
720         make_dir(base, 0755);
721     } else if (!strncmp(uevent->subsystem, "adsp", 4)) {
722         base = "/dev/adsp/";
723         make_dir(base, 0755);
724     } else if (!strncmp(uevent->subsystem, "msm_camera", 10)) {
725         base = "/dev/msm_camera/";
726         make_dir(base, 0755);
727     } else if(!strncmp(uevent->subsystem, "input", 5)) {
728         base = "/dev/input/";
729         make_dir(base, 0755);
730     } else if(!strncmp(uevent->subsystem, "mtd", 3)) {
731         base = "/dev/mtd/";
732         make_dir(base, 0755);
733     } else if(!strncmp(uevent->subsystem, "sound", 5)) {
734         base = "/dev/snd/";
735         make_dir(base, 0755);
736     } else if(!strncmp(uevent->subsystem, "misc", 4) && !strncmp(name, "log_", 4)) {
737         LOG(INFO) << "kernel logger is deprecated";
738         base = "/dev/log/";
739         make_dir(base, 0755);
740         name += 4;
741     } else
742         base = "/dev/";
743     links = get_character_device_symlinks(uevent);
744
745     if (!devpath[0])
746         snprintf(devpath, sizeof(devpath), "%s%s", base, name);
747
748     handle_device(uevent->action, devpath, uevent->path, 0,
749             uevent->major, uevent->minor, links);
750}
751
752static void handle_device_event(struct uevent *uevent)
753{
754    if (!strcmp(uevent->action,"add") || !strcmp(uevent->action, "change") || !strcmp(uevent->action, "online"))
755        fixup_sys_perms(uevent->path, uevent->subsystem);
756
757    if (!strncmp(uevent->subsystem, "block", 5)) {
758        handle_block_device_event(uevent);
759    } else if (!strncmp(uevent->subsystem, "platform", 8)) {
760        handle_platform_device_event(uevent);
761    } else {
762        handle_generic_device_event(uevent);
763    }
764}
765
766static int load_firmware(int fw_fd, int loading_fd, int data_fd)
767{
768    struct stat st;
769    long len_to_copy;
770    int ret = 0;
771
772    if(fstat(fw_fd, &st) < 0)
773        return -1;
774    len_to_copy = st.st_size;
775
776    write(loading_fd, "1", 1);  /* start transfer */
777
778    while (len_to_copy > 0) {
779        char buf[PAGE_SIZE];
780        ssize_t nr;
781
782        nr = read(fw_fd, buf, sizeof(buf));
783        if(!nr)
784            break;
785        if(nr < 0) {
786            ret = -1;
787            break;
788        }
789        if (!android::base::WriteFully(data_fd, buf, nr)) {
790            ret = -1;
791            break;
792        }
793        len_to_copy -= nr;
794    }
795
796    if(!ret)
797        write(loading_fd, "0", 1);  /* successful end of transfer */
798    else
799        write(loading_fd, "-1", 2); /* abort transfer */
800
801    return ret;
802}
803
804static int is_booting(void)
805{
806    return access("/dev/.booting", F_OK) == 0;
807}
808
809static void process_firmware_event(struct uevent *uevent)
810{
811    char *root, *loading, *data;
812    int l, loading_fd, data_fd, fw_fd;
813    size_t i;
814    int booting = is_booting();
815
816    LOG(INFO) << "firmware: loading '" << uevent->firmware << "' for '" << uevent->path << "'";
817
818    l = asprintf(&root, SYSFS_PREFIX"%s/", uevent->path);
819    if (l == -1)
820        return;
821
822    l = asprintf(&loading, "%sloading", root);
823    if (l == -1)
824        goto root_free_out;
825
826    l = asprintf(&data, "%sdata", root);
827    if (l == -1)
828        goto loading_free_out;
829
830    loading_fd = open(loading, O_WRONLY|O_CLOEXEC);
831    if(loading_fd < 0)
832        goto data_free_out;
833
834    data_fd = open(data, O_WRONLY|O_CLOEXEC);
835    if(data_fd < 0)
836        goto loading_close_out;
837
838try_loading_again:
839    for (i = 0; i < arraysize(firmware_dirs); i++) {
840        char *file = NULL;
841        l = asprintf(&file, "%s/%s", firmware_dirs[i], uevent->firmware);
842        if (l == -1)
843            goto data_free_out;
844        fw_fd = open(file, O_RDONLY|O_CLOEXEC);
845        free(file);
846        if (fw_fd >= 0) {
847            if (!load_firmware(fw_fd, loading_fd, data_fd)) {
848                LOG(INFO) << "firmware: copy success { '" << root << "', '" << uevent->firmware << "' }";
849            } else {
850                LOG(ERROR) << "firmware: copy failure { '" << root << "', '" << uevent->firmware << "' }";
851            }
852            break;
853        }
854    }
855    if (fw_fd < 0) {
856        if (booting) {
857            /* If we're not fully booted, we may be missing
858             * filesystems needed for firmware, wait and retry.
859             */
860            usleep(100000);
861            booting = is_booting();
862            goto try_loading_again;
863        }
864        PLOG(ERROR) << "firmware: could not open '" << uevent->firmware << "'";
865        write(loading_fd, "-1", 2);
866        goto data_close_out;
867    }
868
869    close(fw_fd);
870data_close_out:
871    close(data_fd);
872loading_close_out:
873    close(loading_fd);
874data_free_out:
875    free(data);
876loading_free_out:
877    free(loading);
878root_free_out:
879    free(root);
880}
881
882static void handle_firmware_event(struct uevent *uevent)
883{
884    pid_t pid;
885
886    if(strcmp(uevent->subsystem, "firmware"))
887        return;
888
889    if(strcmp(uevent->action, "add"))
890        return;
891
892    /* we fork, to avoid making large memory allocations in init proper */
893    pid = fork();
894    if (!pid) {
895        process_firmware_event(uevent);
896        _exit(EXIT_SUCCESS);
897    } else if (pid < 0) {
898        PLOG(ERROR) << "could not fork to process firmware event";
899    }
900}
901
902#define UEVENT_MSG_LEN  2048
903void handle_device_fd()
904{
905    char msg[UEVENT_MSG_LEN+2];
906    int n;
907    while ((n = uevent_kernel_multicast_recv(device_fd, msg, UEVENT_MSG_LEN)) > 0) {
908        if(n >= UEVENT_MSG_LEN)   /* overflow -- discard */
909            continue;
910
911        msg[n] = '\0';
912        msg[n+1] = '\0';
913
914        struct uevent uevent;
915        parse_event(msg, &uevent);
916
917        if (selinux_status_updated() > 0) {
918            struct selabel_handle *sehandle2;
919            sehandle2 = selinux_android_file_context_handle();
920            if (sehandle2) {
921                selabel_close(sehandle);
922                sehandle = sehandle2;
923            }
924        }
925
926        handle_device_event(&uevent);
927        handle_firmware_event(&uevent);
928    }
929}
930
931/* Coldboot walks parts of the /sys tree and pokes the uevent files
932** to cause the kernel to regenerate device add events that happened
933** before init's device manager was started
934**
935** We drain any pending events from the netlink socket every time
936** we poke another uevent file to make sure we don't overrun the
937** socket's buffer.
938*/
939
940static void do_coldboot(DIR *d)
941{
942    struct dirent *de;
943    int dfd, fd;
944
945    dfd = dirfd(d);
946
947    fd = openat(dfd, "uevent", O_WRONLY);
948    if(fd >= 0) {
949        write(fd, "add\n", 4);
950        close(fd);
951        handle_device_fd();
952    }
953
954    while((de = readdir(d))) {
955        DIR *d2;
956
957        if(de->d_type != DT_DIR || de->d_name[0] == '.')
958            continue;
959
960        fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
961        if(fd < 0)
962            continue;
963
964        d2 = fdopendir(fd);
965        if(d2 == 0)
966            close(fd);
967        else {
968            do_coldboot(d2);
969            closedir(d2);
970        }
971    }
972}
973
974static void coldboot(const char *path)
975{
976    std::unique_ptr<DIR, decltype(&closedir)> d(opendir(path), closedir);
977    if(d) {
978        do_coldboot(d.get());
979    }
980}
981
982void device_init() {
983    sehandle = selinux_android_file_context_handle();
984    selinux_status_open(true);
985
986    /* is 256K enough? udev uses 16MB! */
987    device_fd = uevent_open_socket(256*1024, true);
988    if (device_fd == -1) {
989        return;
990    }
991    fcntl(device_fd, F_SETFL, O_NONBLOCK);
992
993    if (access(COLDBOOT_DONE, F_OK) == 0) {
994        LOG(VERBOSE) << "Skipping coldboot, already done!";
995        return;
996    }
997
998    Timer t;
999    coldboot("/sys/class");
1000    coldboot("/sys/block");
1001    coldboot("/sys/devices");
1002    close(open(COLDBOOT_DONE, O_WRONLY|O_CREAT|O_CLOEXEC, 0000));
1003    LOG(INFO) << "Coldboot took " << t.duration() << "s.";
1004}
1005
1006int get_device_fd()
1007{
1008    return device_fd;
1009}
1010