devices.cpp revision ea23983a9c84db151478c0c5a8b41f7d0c4c3fde 
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 <dirent.h>
18#include <errno.h>
19#include <fcntl.h>
20#include <fnmatch.h>
21#include <libgen.h>
22#include <stddef.h>
23#include <stdio.h>
24#include <stdlib.h>
25#include <string.h>
26#include <sys/sendfile.h>
27#include <sys/socket.h>
28#include <sys/stat.h>
29#include <sys/time.h>
30#include <sys/types.h>
31#include <sys/un.h>
32#include <sys/wait.h>
33#include <unistd.h>
34
35#include <linux/netlink.h>
36
37#include <memory>
38#include <thread>
39
40#include <selinux/selinux.h>
41#include <selinux/label.h>
42#include <selinux/android.h>
43#include <selinux/avc.h>
44
45#include <private/android_filesystem_config.h>
46
47#include <android-base/file.h>
48#include <android-base/stringprintf.h>
49#include <android-base/unique_fd.h>
50#include <cutils/list.h>
51#include <cutils/uevent.h>
52
53#include "devices.h"
54#include "ueventd_parser.h"
55#include "util.h"
56#include "log.h"
57
58#define SYSFS_PREFIX    "/sys"
59static const char *firmware_dirs[] = { "/etc/firmware",
60                                       "/vendor/firmware",
61                                       "/firmware/image" };
62
63extern struct selabel_handle *sehandle;
64
65static int device_fd = -1;
66
67struct uevent {
68    const char *action;
69    const char *path;
70    const char *subsystem;
71    const char *firmware;
72    const char *partition_name;
73    const char *device_name;
74    int partition_num;
75    int major;
76    int minor;
77};
78
79struct perms_ {
80    char *name;
81    char *attr;
82    mode_t perm;
83    unsigned int uid;
84    unsigned int gid;
85    unsigned short prefix;
86    unsigned short wildcard;
87};
88
89struct perm_node {
90    struct perms_ dp;
91    struct listnode plist;
92};
93
94struct platform_node {
95    char *name;
96    char *path;
97    int path_len;
98    struct listnode list;
99};
100
101static list_declare(sys_perms);
102static list_declare(dev_perms);
103static list_declare(platform_names);
104
105int add_dev_perms(const char *name, const char *attr,
106                  mode_t perm, unsigned int uid, unsigned int gid,
107                  unsigned short prefix,
108                  unsigned short wildcard) {
109    struct perm_node *node = (perm_node*) calloc(1, sizeof(*node));
110    if (!node)
111        return -ENOMEM;
112
113    node->dp.name = strdup(name);
114    if (!node->dp.name) {
115        free(node);
116        return -ENOMEM;
117    }
118
119    if (attr) {
120        node->dp.attr = strdup(attr);
121        if (!node->dp.attr) {
122            free(node->dp.name);
123            free(node);
124            return -ENOMEM;
125        }
126    }
127
128    node->dp.perm = perm;
129    node->dp.uid = uid;
130    node->dp.gid = gid;
131    node->dp.prefix = prefix;
132    node->dp.wildcard = wildcard;
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
142static bool perm_path_matches(const char *path, struct perms_ *dp)
143{
144    if (dp->prefix) {
145        if (strncmp(path, dp->name, strlen(dp->name)) == 0)
146            return true;
147    } else if (dp->wildcard) {
148        if (fnmatch(dp->name, path, FNM_PATHNAME) == 0)
149            return true;
150    } else {
151        if (strcmp(path, dp->name) == 0)
152            return true;
153    }
154
155    return false;
156}
157
158static bool match_subsystem(perms_* dp, const char* pattern,
159                            const char* path, const char* subsystem) {
160    if (!pattern || !subsystem || strstr(dp->name, subsystem) == NULL) {
161        return false;
162    }
163
164    std::string subsys_path = android::base::StringPrintf(pattern, subsystem, basename(path));
165    return perm_path_matches(subsys_path.c_str(), dp);
166}
167
168static void fixup_sys_perms(const char* upath, const char* subsystem) {
169    // upaths omit the "/sys" that paths in this list
170    // contain, so we prepend it...
171    std::string path = std::string(SYSFS_PREFIX) + upath;
172
173    listnode* node;
174    list_for_each(node, &sys_perms) {
175        perms_* dp = &(node_to_item(node, perm_node, plist))->dp;
176        if (match_subsystem(dp, SYSFS_PREFIX "/class/%s/%s", path.c_str(), subsystem)) {
177            ; // matched
178        } else if (match_subsystem(dp, SYSFS_PREFIX "/bus/%s/devices/%s", path.c_str(), subsystem)) {
179            ; // matched
180        } else if (!perm_path_matches(path.c_str(), dp)) {
181            continue;
182        }
183
184        std::string attr_file = path + "/" + dp->attr;
185        LOG(INFO) << "fixup " << attr_file
186                  << " " << dp->uid << " " << dp->gid << " " << std::oct << dp->perm;
187        chown(attr_file.c_str(), dp->uid, dp->gid);
188        chmod(attr_file.c_str(), dp->perm);
189    }
190
191    if (access(path.c_str(), F_OK) == 0) {
192        LOG(VERBOSE) << "restorecon_recursive: " << path;
193        restorecon(path.c_str(), SELINUX_ANDROID_RESTORECON_RECURSE);
194    }
195}
196
197static mode_t get_device_perm(const char *path, const char **links,
198                unsigned *uid, unsigned *gid)
199{
200    struct listnode *node;
201    struct perm_node *perm_node;
202    struct perms_ *dp;
203
204    /* search the perms list in reverse so that ueventd.$hardware can
205     * override ueventd.rc
206     */
207    list_for_each_reverse(node, &dev_perms) {
208        bool match = false;
209
210        perm_node = node_to_item(node, struct perm_node, plist);
211        dp = &perm_node->dp;
212
213        if (perm_path_matches(path, dp)) {
214            match = true;
215        } else {
216            if (links) {
217                int i;
218                for (i = 0; links[i]; i++) {
219                    if (perm_path_matches(links[i], dp)) {
220                        match = true;
221                        break;
222                    }
223                }
224            }
225        }
226
227        if (match) {
228            *uid = dp->uid;
229            *gid = dp->gid;
230            return dp->perm;
231        }
232    }
233    /* Default if nothing found. */
234    *uid = 0;
235    *gid = 0;
236    return 0600;
237}
238
239static void make_device(const char *path,
240                        const char */*upath*/,
241                        int block, int major, int minor,
242                        const char **links)
243{
244    unsigned uid;
245    unsigned gid;
246    mode_t mode;
247    dev_t dev;
248    char *secontext = NULL;
249
250    mode = get_device_perm(path, links, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
251
252    if (sehandle) {
253        if (selabel_lookup_best_match(sehandle, &secontext, path, links, mode)) {
254            PLOG(ERROR) << "Device '" << path << "' not created; cannot find SELinux label";
255            return;
256        }
257        setfscreatecon(secontext);
258    }
259
260    dev = makedev(major, minor);
261    /* Temporarily change egid to avoid race condition setting the gid of the
262     * device node. Unforunately changing the euid would prevent creation of
263     * some device nodes, so the uid has to be set with chown() and is still
264     * racy. Fixing the gid race at least fixed the issue with system_server
265     * opening dynamic input devices under the AID_INPUT gid. */
266    setegid(gid);
267    /* If the node already exists update its SELinux label to handle cases when
268     * it was created with the wrong context during coldboot procedure. */
269    if (mknod(path, mode, dev) && (errno == EEXIST) && secontext) {
270
271        char* fcon = nullptr;
272        int rc = lgetfilecon(path, &fcon);
273        if (rc < 0) {
274            PLOG(ERROR) << "Cannot get SELinux label on '" << path << "' device";
275            goto out;
276        }
277
278        bool different = strcmp(fcon, secontext) != 0;
279        freecon(fcon);
280
281        if (different && lsetfilecon(path, secontext)) {
282            PLOG(ERROR) << "Cannot set '" << secontext << "' SELinux label on '" << path << "' device";
283        }
284    }
285
286out:
287    chown(path, uid, -1);
288    setegid(AID_ROOT);
289
290    if (secontext) {
291        freecon(secontext);
292        setfscreatecon(NULL);
293    }
294}
295
296static void add_platform_device(const char *path)
297{
298    int path_len = strlen(path);
299    struct platform_node *bus;
300    const char *name = path;
301
302    if (!strncmp(path, "/devices/", 9)) {
303        name += 9;
304        if (!strncmp(name, "platform/", 9))
305            name += 9;
306    }
307
308    LOG(VERBOSE) << "adding platform device " << name << " (" << path << ")";
309
310    bus = (platform_node*) calloc(1, sizeof(struct platform_node));
311    bus->path = strdup(path);
312    bus->path_len = path_len;
313    bus->name = bus->path + (name - path);
314    list_add_tail(&platform_names, &bus->list);
315}
316
317/*
318 * given a path that may start with a platform device, find the length of the
319 * platform device prefix.  If it doesn't start with a platform device, return
320 * 0.
321 */
322static struct platform_node *find_platform_device(const char *path)
323{
324    int path_len = strlen(path);
325    struct listnode *node;
326    struct platform_node *bus;
327
328    list_for_each_reverse(node, &platform_names) {
329        bus = node_to_item(node, struct platform_node, list);
330        if ((bus->path_len < path_len) &&
331                (path[bus->path_len] == '/') &&
332                !strncmp(path, bus->path, bus->path_len))
333            return bus;
334    }
335
336    return NULL;
337}
338
339static void remove_platform_device(const char *path)
340{
341    struct listnode *node;
342    struct platform_node *bus;
343
344    list_for_each_reverse(node, &platform_names) {
345        bus = node_to_item(node, struct platform_node, list);
346        if (!strcmp(path, bus->path)) {
347            LOG(INFO) << "removing platform device " << bus->name;
348            free(bus->path);
349            list_remove(node);
350            free(bus);
351            return;
352        }
353    }
354}
355
356/* Given a path that may start with a PCI device, populate the supplied buffer
357 * with the PCI domain/bus number and the peripheral ID and return 0.
358 * If it doesn't start with a PCI device, or there is some error, return -1 */
359static int find_pci_device_prefix(const char *path, char *buf, ssize_t buf_sz)
360{
361    const char *start, *end;
362
363    if (strncmp(path, "/devices/pci", 12))
364        return -1;
365
366    /* Beginning of the prefix is the initial "pci" after "/devices/" */
367    start = path + 9;
368
369    /* End of the prefix is two path '/' later, capturing the domain/bus number
370     * and the peripheral ID. Example: pci0000:00/0000:00:1f.2 */
371    end = strchr(start, '/');
372    if (!end)
373        return -1;
374    end = strchr(end + 1, '/');
375    if (!end)
376        return -1;
377
378    /* Make sure we have enough room for the string plus null terminator */
379    if (end - start + 1 > buf_sz)
380        return -1;
381
382    strncpy(buf, start, end - start);
383    buf[end - start] = '\0';
384    return 0;
385}
386
387static void parse_event(const char *msg, struct uevent *uevent)
388{
389    uevent->action = "";
390    uevent->path = "";
391    uevent->subsystem = "";
392    uevent->firmware = "";
393    uevent->major = -1;
394    uevent->minor = -1;
395    uevent->partition_name = NULL;
396    uevent->partition_num = -1;
397    uevent->device_name = NULL;
398
399        /* currently ignoring SEQNUM */
400    while(*msg) {
401        if(!strncmp(msg, "ACTION=", 7)) {
402            msg += 7;
403            uevent->action = msg;
404        } else if(!strncmp(msg, "DEVPATH=", 8)) {
405            msg += 8;
406            uevent->path = msg;
407        } else if(!strncmp(msg, "SUBSYSTEM=", 10)) {
408            msg += 10;
409            uevent->subsystem = msg;
410        } else if(!strncmp(msg, "FIRMWARE=", 9)) {
411            msg += 9;
412            uevent->firmware = msg;
413        } else if(!strncmp(msg, "MAJOR=", 6)) {
414            msg += 6;
415            uevent->major = atoi(msg);
416        } else if(!strncmp(msg, "MINOR=", 6)) {
417            msg += 6;
418            uevent->minor = atoi(msg);
419        } else if(!strncmp(msg, "PARTN=", 6)) {
420            msg += 6;
421            uevent->partition_num = atoi(msg);
422        } else if(!strncmp(msg, "PARTNAME=", 9)) {
423            msg += 9;
424            uevent->partition_name = msg;
425        } else if(!strncmp(msg, "DEVNAME=", 8)) {
426            msg += 8;
427            uevent->device_name = msg;
428        }
429
430        /* advance to after the next \0 */
431        while(*msg++)
432            ;
433    }
434
435    if (LOG_UEVENTS) {
436        LOG(INFO) << android::base::StringPrintf("event { '%s', '%s', '%s', '%s', %d, %d }",
437                                                 uevent->action, uevent->path, uevent->subsystem,
438                                                 uevent->firmware, uevent->major, uevent->minor);
439    }
440}
441
442static char **get_character_device_symlinks(struct uevent *uevent)
443{
444    const char *parent;
445    const char *slash;
446    char **links;
447    int link_num = 0;
448    int width;
449    struct platform_node *pdev;
450
451    pdev = find_platform_device(uevent->path);
452    if (!pdev)
453        return NULL;
454
455    links = (char**) malloc(sizeof(char *) * 2);
456    if (!links)
457        return NULL;
458    memset(links, 0, sizeof(char *) * 2);
459
460    /* skip "/devices/platform/<driver>" */
461    parent = strchr(uevent->path + pdev->path_len, '/');
462    if (!parent)
463        goto err;
464
465    if (!strncmp(parent, "/usb", 4)) {
466        /* skip root hub name and device. use device interface */
467        while (*++parent && *parent != '/');
468        if (*parent)
469            while (*++parent && *parent != '/');
470        if (!*parent)
471            goto err;
472        slash = strchr(++parent, '/');
473        if (!slash)
474            goto err;
475        width = slash - parent;
476        if (width <= 0)
477            goto err;
478
479        if (asprintf(&links[link_num], "/dev/usb/%s%.*s", uevent->subsystem, width, parent) > 0)
480            link_num++;
481        else
482            links[link_num] = NULL;
483        mkdir("/dev/usb", 0755);
484    }
485    else {
486        goto err;
487    }
488
489    return links;
490err:
491    free(links);
492    return NULL;
493}
494
495static char **get_block_device_symlinks(struct uevent *uevent)
496{
497    const char *device;
498    struct platform_node *pdev;
499    const char *slash;
500    const char *type;
501    char buf[256];
502    char link_path[256];
503    int link_num = 0;
504    char *p;
505
506    pdev = find_platform_device(uevent->path);
507    if (pdev) {
508        device = pdev->name;
509        type = "platform";
510    } else if (!find_pci_device_prefix(uevent->path, buf, sizeof(buf))) {
511        device = buf;
512        type = "pci";
513    } else {
514        return NULL;
515    }
516
517    char **links = (char**) malloc(sizeof(char *) * 4);
518    if (!links)
519        return NULL;
520    memset(links, 0, sizeof(char *) * 4);
521
522    LOG(INFO) << "found " << type << " device " << device;
523
524    snprintf(link_path, sizeof(link_path), "/dev/block/%s/%s", type, device);
525
526    if (uevent->partition_name) {
527        p = strdup(uevent->partition_name);
528        sanitize(p);
529        if (strcmp(uevent->partition_name, p)) {
530            LOG(VERBOSE) << "Linking partition '" << uevent->partition_name << "' as '" << p << "'";
531        }
532        if (asprintf(&links[link_num], "%s/by-name/%s", link_path, p) > 0)
533            link_num++;
534        else
535            links[link_num] = NULL;
536        free(p);
537    }
538
539    if (uevent->partition_num >= 0) {
540        if (asprintf(&links[link_num], "%s/by-num/p%d", link_path, uevent->partition_num) > 0)
541            link_num++;
542        else
543            links[link_num] = NULL;
544    }
545
546    slash = strrchr(uevent->path, '/');
547    if (asprintf(&links[link_num], "%s/%s", link_path, slash + 1) > 0)
548        link_num++;
549    else
550        links[link_num] = NULL;
551
552    return links;
553}
554
555static void make_link_init(const char* oldpath, const char* newpath) {
556  const char* slash = strrchr(newpath, '/');
557  if (!slash) return;
558
559  if (mkdir_recursive(dirname(newpath), 0755)) {
560    PLOG(ERROR) << "Failed to create directory " << dirname(newpath);
561  }
562
563  if (symlink(oldpath, newpath) && errno != EEXIST) {
564    PLOG(ERROR) << "Failed to symlink " << oldpath << " to " << newpath;
565  }
566}
567
568static void remove_link(const char* oldpath, const char* newpath) {
569  std::string path;
570  if (android::base::Readlink(newpath, &path) && path == oldpath) unlink(newpath);
571}
572
573static void handle_device(const char *action, const char *devpath,
574        const char *path, int block, int major, int minor, char **links)
575{
576    if(!strcmp(action, "add")) {
577        make_device(devpath, path, block, major, minor, (const char **)links);
578        if (links) {
579            for (int i = 0; links[i]; i++) {
580                make_link_init(devpath, links[i]);
581            }
582        }
583    }
584
585    if(!strcmp(action, "remove")) {
586        if (links) {
587            for (int i = 0; links[i]; i++) {
588                remove_link(devpath, links[i]);
589            }
590        }
591        unlink(devpath);
592    }
593
594    if (links) {
595        for (int i = 0; links[i]; i++) {
596            free(links[i]);
597        }
598        free(links);
599    }
600}
601
602static void handle_platform_device_event(struct uevent *uevent)
603{
604    const char *path = uevent->path;
605
606    if (!strcmp(uevent->action, "add"))
607        add_platform_device(path);
608    else if (!strcmp(uevent->action, "remove"))
609        remove_platform_device(path);
610}
611
612static const char *parse_device_name(struct uevent *uevent, unsigned int len)
613{
614    const char *name;
615
616    /* if it's not a /dev device, nothing else to do */
617    if((uevent->major < 0) || (uevent->minor < 0))
618        return NULL;
619
620    /* do we have a name? */
621    name = strrchr(uevent->path, '/');
622    if(!name)
623        return NULL;
624    name++;
625
626    /* too-long names would overrun our buffer */
627    if(strlen(name) > len) {
628        LOG(ERROR) << "DEVPATH=" << name << " exceeds " << len << "-character limit on filename; ignoring event";
629        return NULL;
630    }
631
632    return name;
633}
634
635#define DEVPATH_LEN 96
636#define MAX_DEV_NAME 64
637
638static void handle_block_device_event(struct uevent *uevent)
639{
640    const char *base = "/dev/block/";
641    const char *name;
642    char devpath[DEVPATH_LEN];
643    char **links = NULL;
644
645    name = parse_device_name(uevent, MAX_DEV_NAME);
646    if (!name)
647        return;
648
649    snprintf(devpath, sizeof(devpath), "%s%s", base, name);
650    make_dir(base, 0755);
651
652    if (!strncmp(uevent->path, "/devices/", 9))
653        links = get_block_device_symlinks(uevent);
654
655    handle_device(uevent->action, devpath, uevent->path, 1,
656            uevent->major, uevent->minor, links);
657}
658
659static bool assemble_devpath(char *devpath, const char *dirname,
660        const char *devname)
661{
662    int s = snprintf(devpath, DEVPATH_LEN, "%s/%s", dirname, devname);
663    if (s < 0) {
664        PLOG(ERROR) << "failed to assemble device path; ignoring event";
665        return false;
666    } else if (s >= DEVPATH_LEN) {
667        LOG(ERROR) << dirname << "/" << devname
668                   << " exceeds " << DEVPATH_LEN << "-character limit on path; ignoring event";
669        return false;
670    }
671    return true;
672}
673
674static void mkdir_recursive_for_devpath(const char *devpath)
675{
676    char dir[DEVPATH_LEN];
677    char *slash;
678
679    strcpy(dir, devpath);
680    slash = strrchr(dir, '/');
681    *slash = '\0';
682    mkdir_recursive(dir, 0755);
683}
684
685static void handle_generic_device_event(struct uevent *uevent)
686{
687    const char *base;
688    const char *name;
689    char devpath[DEVPATH_LEN] = {0};
690    char **links = NULL;
691
692    name = parse_device_name(uevent, MAX_DEV_NAME);
693    if (!name)
694        return;
695
696    struct ueventd_subsystem *subsystem =
697            ueventd_subsystem_find_by_name(uevent->subsystem);
698
699    if (subsystem) {
700        const char *devname;
701
702        switch (subsystem->devname_src) {
703        case DEVNAME_UEVENT_DEVNAME:
704            devname = uevent->device_name;
705            break;
706
707        case DEVNAME_UEVENT_DEVPATH:
708            devname = name;
709            break;
710
711        default:
712            LOG(ERROR) << uevent->subsystem << " subsystem's devpath option is not set; ignoring event";
713            return;
714        }
715
716        if (!assemble_devpath(devpath, subsystem->dirname, devname))
717            return;
718        mkdir_recursive_for_devpath(devpath);
719    } else if (!strncmp(uevent->subsystem, "usb", 3)) {
720         if (!strcmp(uevent->subsystem, "usb")) {
721            if (uevent->device_name) {
722                if (!assemble_devpath(devpath, "/dev", uevent->device_name))
723                    return;
724                mkdir_recursive_for_devpath(devpath);
725             }
726             else {
727                 /* This imitates the file system that would be created
728                  * if we were using devfs instead.
729                  * Minors are broken up into groups of 128, starting at "001"
730                  */
731                 int bus_id = uevent->minor / 128 + 1;
732                 int device_id = uevent->minor % 128 + 1;
733                 /* build directories */
734                 make_dir("/dev/bus", 0755);
735                 make_dir("/dev/bus/usb", 0755);
736                 snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d", bus_id);
737                 make_dir(devpath, 0755);
738                 snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d/%03d", bus_id, device_id);
739             }
740         } else {
741             /* ignore other USB events */
742             return;
743         }
744     } else if (!strncmp(uevent->subsystem, "graphics", 8)) {
745         base = "/dev/graphics/";
746         make_dir(base, 0755);
747     } else if (!strncmp(uevent->subsystem, "drm", 3)) {
748         base = "/dev/dri/";
749         make_dir(base, 0755);
750     } else if (!strncmp(uevent->subsystem, "oncrpc", 6)) {
751         base = "/dev/oncrpc/";
752         make_dir(base, 0755);
753     } else if (!strncmp(uevent->subsystem, "adsp", 4)) {
754         base = "/dev/adsp/";
755         make_dir(base, 0755);
756     } else if (!strncmp(uevent->subsystem, "msm_camera", 10)) {
757         base = "/dev/msm_camera/";
758         make_dir(base, 0755);
759     } else if(!strncmp(uevent->subsystem, "input", 5)) {
760         base = "/dev/input/";
761         make_dir(base, 0755);
762     } else if(!strncmp(uevent->subsystem, "mtd", 3)) {
763         base = "/dev/mtd/";
764         make_dir(base, 0755);
765     } else if(!strncmp(uevent->subsystem, "sound", 5)) {
766         base = "/dev/snd/";
767         make_dir(base, 0755);
768     } else if(!strncmp(uevent->subsystem, "misc", 4) && !strncmp(name, "log_", 4)) {
769         LOG(INFO) << "kernel logger is deprecated";
770         base = "/dev/log/";
771         make_dir(base, 0755);
772         name += 4;
773     } else
774         base = "/dev/";
775     links = get_character_device_symlinks(uevent);
776
777     if (!devpath[0])
778         snprintf(devpath, sizeof(devpath), "%s%s", base, name);
779
780     handle_device(uevent->action, devpath, uevent->path, 0,
781             uevent->major, uevent->minor, links);
782}
783
784static void handle_device_event(struct uevent *uevent)
785{
786    if (!strcmp(uevent->action,"add") || !strcmp(uevent->action, "change") || !strcmp(uevent->action, "online"))
787        fixup_sys_perms(uevent->path, uevent->subsystem);
788
789    if (!strncmp(uevent->subsystem, "block", 5)) {
790        handle_block_device_event(uevent);
791    } else if (!strncmp(uevent->subsystem, "platform", 8)) {
792        handle_platform_device_event(uevent);
793    } else {
794        handle_generic_device_event(uevent);
795    }
796}
797
798static void load_firmware(uevent* uevent, const std::string& root,
799                          int fw_fd, size_t fw_size,
800                          int loading_fd, int data_fd) {
801    // Start transfer.
802    android::base::WriteFully(loading_fd, "1", 1);
803
804    // Copy the firmware.
805    int rc = sendfile(data_fd, fw_fd, nullptr, fw_size);
806    if (rc == -1) {
807        PLOG(ERROR) << "firmware: sendfile failed { '" << root << "', '" << uevent->firmware << "' }";
808    }
809
810    // Tell the firmware whether to abort or commit.
811    const char* response = (rc != -1) ? "0" : "-1";
812    android::base::WriteFully(loading_fd, response, strlen(response));
813}
814
815static int is_booting() {
816    return access("/dev/.booting", F_OK) == 0;
817}
818
819static void process_firmware_event(uevent* uevent) {
820    int booting = is_booting();
821
822    LOG(INFO) << "firmware: loading '" << uevent->firmware << "' for '" << uevent->path << "'";
823
824    std::string root = android::base::StringPrintf("/sys%s", uevent->path);
825    std::string loading = root + "/loading";
826    std::string data = root + "/data";
827
828    android::base::unique_fd loading_fd(open(loading.c_str(), O_WRONLY|O_CLOEXEC));
829    if (loading_fd == -1) {
830        PLOG(ERROR) << "couldn't open firmware loading fd for " << uevent->firmware;
831        return;
832    }
833
834    android::base::unique_fd data_fd(open(data.c_str(), O_WRONLY|O_CLOEXEC));
835    if (data_fd == -1) {
836        PLOG(ERROR) << "couldn't open firmware data fd for " << uevent->firmware;
837        return;
838    }
839
840try_loading_again:
841    for (size_t i = 0; i < arraysize(firmware_dirs); i++) {
842        std::string file = android::base::StringPrintf("%s/%s", firmware_dirs[i], uevent->firmware);
843        android::base::unique_fd fw_fd(open(file.c_str(), O_RDONLY|O_CLOEXEC));
844        struct stat sb;
845        if (fw_fd != -1 && fstat(fw_fd, &sb) != -1) {
846            load_firmware(uevent, root, fw_fd, sb.st_size, loading_fd, data_fd);
847            return;
848        }
849    }
850
851    if (booting) {
852        // If we're not fully booted, we may be missing
853        // filesystems needed for firmware, wait and retry.
854        std::this_thread::sleep_for(100ms);
855        booting = is_booting();
856        goto try_loading_again;
857    }
858
859    LOG(ERROR) << "firmware: could not find firmware for " << uevent->firmware;
860
861    // Write "-1" as our response to the kernel's firmware request, since we have nothing for it.
862    write(loading_fd, "-1", 2);
863}
864
865static void handle_firmware_event(uevent* uevent) {
866    if (strcmp(uevent->subsystem, "firmware")) return;
867    if (strcmp(uevent->action, "add")) return;
868
869    // Loading the firmware in a child means we can do that in parallel...
870    // (We ignore SIGCHLD rather than wait for our children.)
871    pid_t pid = fork();
872    if (pid == 0) {
873        Timer t;
874        process_firmware_event(uevent);
875        LOG(INFO) << "loading " << uevent->path << " took " << t;
876        _exit(EXIT_SUCCESS);
877    } else if (pid == -1) {
878        PLOG(ERROR) << "could not fork to process firmware event for " << uevent->firmware;
879    }
880}
881
882#define UEVENT_MSG_LEN  2048
883
884static inline void handle_device_fd_with(void (handle_uevent)(struct uevent*))
885{
886    char msg[UEVENT_MSG_LEN+2];
887    int n;
888    while ((n = uevent_kernel_multicast_recv(device_fd, msg, UEVENT_MSG_LEN)) > 0) {
889        if(n >= UEVENT_MSG_LEN)   /* overflow -- discard */
890            continue;
891
892        msg[n] = '\0';
893        msg[n+1] = '\0';
894
895        struct uevent uevent;
896        parse_event(msg, &uevent);
897        handle_uevent(&uevent);
898    }
899}
900
901void handle_device_fd()
902{
903    handle_device_fd_with(
904        [](struct uevent *uevent) {
905            if (selinux_status_updated() > 0) {
906                struct selabel_handle *sehandle2;
907                sehandle2 = selinux_android_file_context_handle();
908                if (sehandle2) {
909                    selabel_close(sehandle);
910                    sehandle = sehandle2;
911                }
912            }
913
914            handle_device_event(uevent);
915            handle_firmware_event(uevent);
916        });
917}
918
919/* Coldboot walks parts of the /sys tree and pokes the uevent files
920** to cause the kernel to regenerate device add events that happened
921** before init's device manager was started
922**
923** We drain any pending events from the netlink socket every time
924** we poke another uevent file to make sure we don't overrun the
925** socket's buffer.
926*/
927
928static void do_coldboot(DIR *d)
929{
930    struct dirent *de;
931    int dfd, fd;
932
933    dfd = dirfd(d);
934
935    fd = openat(dfd, "uevent", O_WRONLY);
936    if(fd >= 0) {
937        write(fd, "add\n", 4);
938        close(fd);
939        handle_device_fd();
940    }
941
942    while((de = readdir(d))) {
943        DIR *d2;
944
945        if(de->d_type != DT_DIR || de->d_name[0] == '.')
946            continue;
947
948        fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
949        if(fd < 0)
950            continue;
951
952        d2 = fdopendir(fd);
953        if(d2 == 0)
954            close(fd);
955        else {
956            do_coldboot(d2);
957            closedir(d2);
958        }
959    }
960}
961
962static void coldboot(const char *path)
963{
964    std::unique_ptr<DIR, decltype(&closedir)> d(opendir(path), closedir);
965    if(d) {
966        do_coldboot(d.get());
967    }
968}
969
970static void early_uevent_handler(struct uevent *uevent, const char *base, bool is_block)
971{
972    const char *name;
973    char devpath[DEVPATH_LEN];
974
975    if (is_block && strncmp(uevent->subsystem, "block", 5))
976        return;
977
978    name = parse_device_name(uevent, MAX_DEV_NAME);
979    if (!name) {
980        LOG(ERROR) << "Failed to parse dev name from uevent: " << uevent->action
981                   << " " << uevent->partition_name << " " << uevent->partition_num
982                   << " " << uevent->major << ":" << uevent->minor;
983        return;
984    }
985
986    snprintf(devpath, sizeof(devpath), "%s%s", base, name);
987    make_dir(base, 0755);
988
989    dev_t dev = makedev(uevent->major, uevent->minor);
990    mode_t mode = 0600 | (is_block ? S_IFBLK : S_IFCHR);
991    mknod(devpath, mode, dev);
992}
993
994void early_create_dev(const std::string& syspath, early_device_type dev_type)
995{
996    android::base::unique_fd dfd(open(syspath.c_str(), O_RDONLY));
997    if (dfd < 0) {
998        LOG(ERROR) << "Failed to open " << syspath;
999        return;
1000    }
1001
1002    android::base::unique_fd fd(openat(dfd, "uevent", O_WRONLY));
1003    if (fd < 0) {
1004        LOG(ERROR) << "Failed to open " << syspath << "/uevent";
1005        return;
1006    }
1007
1008    fcntl(device_fd, F_SETFL, O_NONBLOCK);
1009
1010    write(fd, "add\n", 4);
1011    handle_device_fd_with(dev_type == EARLY_BLOCK_DEV ?
1012        [](struct uevent *uevent) {
1013            early_uevent_handler(uevent, "/dev/block/", true);
1014        } :
1015        [](struct uevent *uevent) {
1016            early_uevent_handler(uevent, "/dev/", false);
1017        });
1018}
1019
1020int early_device_socket_open() {
1021    device_fd = uevent_open_socket(256*1024, true);
1022    return device_fd < 0;
1023}
1024
1025void early_device_socket_close() {
1026    close(device_fd);
1027}
1028
1029void device_init() {
1030    sehandle = selinux_android_file_context_handle();
1031    selinux_status_open(true);
1032
1033    /* is 256K enough? udev uses 16MB! */
1034    device_fd = uevent_open_socket(256*1024, true);
1035    if (device_fd == -1) {
1036        return;
1037    }
1038    fcntl(device_fd, F_SETFL, O_NONBLOCK);
1039
1040    if (access(COLDBOOT_DONE, F_OK) == 0) {
1041        LOG(VERBOSE) << "Skipping coldboot, already done!";
1042        return;
1043    }
1044
1045    Timer t;
1046    coldboot("/sys/class");
1047    coldboot("/sys/block");
1048    coldboot("/sys/devices");
1049    close(open(COLDBOOT_DONE, O_WRONLY|O_CREAT|O_CLOEXEC, 0000));
1050    LOG(INFO) << "Coldboot took " << t;
1051}
1052
1053int get_device_fd() {
1054    return device_fd;
1055}
1056