devices.c revision 7ca8f1243b68147c317aa5c6172fc4a7a1ef2567 
1/*
2 * Copyright (C) 2007 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <errno.h>
18#include <stdio.h>
19#include <stdlib.h>
20#include <sys/stat.h>
21#include <sys/types.h>
22
23#include <fcntl.h>
24#include <dirent.h>
25#include <unistd.h>
26#include <string.h>
27
28#include <sys/socket.h>
29#include <sys/un.h>
30#include <linux/netlink.h>
31#include <private/android_filesystem_config.h>
32#include <sys/time.h>
33#include <asm/page.h>
34#include <sys/wait.h>
35
36#include "devices.h"
37#include "util.h"
38#include "log.h"
39#include "list.h"
40
41#define SYSFS_PREFIX    "/sys"
42#define FIRMWARE_DIR1   "/etc/firmware"
43#define FIRMWARE_DIR2   "/vendor/firmware"
44
45static int device_fd = -1;
46
47struct uevent {
48    const char *action;
49    const char *path;
50    const char *subsystem;
51    const char *firmware;
52    const char *partition_name;
53    int partition_num;
54    int major;
55    int minor;
56};
57
58static int open_uevent_socket(void)
59{
60    struct sockaddr_nl addr;
61    int sz = 64*1024; // XXX larger? udev uses 16MB!
62    int on = 1;
63    int s;
64
65    memset(&addr, 0, sizeof(addr));
66    addr.nl_family = AF_NETLINK;
67    addr.nl_pid = getpid();
68    addr.nl_groups = 0xffffffff;
69
70    s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
71    if(s < 0)
72        return -1;
73
74    setsockopt(s, SOL_SOCKET, SO_RCVBUFFORCE, &sz, sizeof(sz));
75    setsockopt(s, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
76
77    if(bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
78        close(s);
79        return -1;
80    }
81
82    return s;
83}
84
85struct perms_ {
86    char *name;
87    char *attr;
88    mode_t perm;
89    unsigned int uid;
90    unsigned int gid;
91    unsigned short prefix;
92};
93
94struct perm_node {
95    struct perms_ dp;
96    struct listnode plist;
97};
98
99static list_declare(sys_perms);
100static list_declare(dev_perms);
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    struct perm_node *node = calloc(1, sizeof(*node));
106    if (!node)
107        return -ENOMEM;
108
109    node->dp.name = strdup(name);
110    if (!node->dp.name)
111        return -ENOMEM;
112
113    if (attr) {
114        node->dp.attr = strdup(attr);
115        if (!node->dp.attr)
116            return -ENOMEM;
117    }
118
119    node->dp.perm = perm;
120    node->dp.uid = uid;
121    node->dp.gid = gid;
122    node->dp.prefix = prefix;
123
124    if (attr)
125        list_add_tail(&sys_perms, &node->plist);
126    else
127        list_add_tail(&dev_perms, &node->plist);
128
129    return 0;
130}
131
132void fixup_sys_perms(const char *upath)
133{
134    char buf[512];
135    struct listnode *node;
136    struct perms_ *dp;
137
138        /* upaths omit the "/sys" that paths in this list
139         * contain, so we add 4 when comparing...
140         */
141    list_for_each(node, &sys_perms) {
142        dp = &(node_to_item(node, struct perm_node, plist))->dp;
143        if (dp->prefix) {
144            if (strncmp(upath, dp->name + 4, strlen(dp->name + 4)))
145                continue;
146        } else {
147            if (strcmp(upath, dp->name + 4))
148                continue;
149        }
150
151        if ((strlen(upath) + strlen(dp->attr) + 6) > sizeof(buf))
152            return;
153
154        sprintf(buf,"/sys%s/%s", upath, dp->attr);
155        INFO("fixup %s %d %d 0%o\n", buf, dp->uid, dp->gid, dp->perm);
156        chown(buf, dp->uid, dp->gid);
157        chmod(buf, dp->perm);
158    }
159}
160
161static mode_t get_device_perm(const char *path, unsigned *uid, unsigned *gid)
162{
163    mode_t perm;
164    struct listnode *node;
165    struct perm_node *perm_node;
166    struct perms_ *dp;
167
168    /* search the perms list in reverse so that ueventd.$hardware can
169     * override ueventd.rc
170     */
171    list_for_each_reverse(node, &dev_perms) {
172        perm_node = node_to_item(node, struct perm_node, plist);
173        dp = &perm_node->dp;
174
175        if (dp->prefix) {
176            if (strncmp(path, dp->name, strlen(dp->name)))
177                continue;
178        } else {
179            if (strcmp(path, dp->name))
180                continue;
181        }
182        *uid = dp->uid;
183        *gid = dp->gid;
184        return dp->perm;
185    }
186    /* Default if nothing found. */
187    *uid = 0;
188    *gid = 0;
189    return 0600;
190}
191
192static void make_device(const char *path,
193                        const char *upath,
194                        int block, int major, int minor)
195{
196    unsigned uid;
197    unsigned gid;
198    mode_t mode;
199    dev_t dev;
200
201    mode = get_device_perm(path, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
202    dev = makedev(major, minor);
203    /* Temporarily change egid to avoid race condition setting the gid of the
204     * device node. Unforunately changing the euid would prevent creation of
205     * some device nodes, so the uid has to be set with chown() and is still
206     * racy. Fixing the gid race at least fixed the issue with system_server
207     * opening dynamic input devices under the AID_INPUT gid. */
208    setegid(gid);
209    mknod(path, mode, dev);
210    chown(path, uid, -1);
211    setegid(AID_ROOT);
212}
213
214#if LOG_UEVENTS
215
216static inline suseconds_t get_usecs(void)
217{
218    struct timeval tv;
219    gettimeofday(&tv, 0);
220    return tv.tv_sec * (suseconds_t) 1000000 + tv.tv_usec;
221}
222
223#define log_event_print(x...) INFO(x)
224
225#else
226
227#define log_event_print(fmt, args...)   do { } while (0)
228#define get_usecs()                     0
229
230#endif
231
232static void parse_event(const char *msg, struct uevent *uevent)
233{
234    uevent->action = "";
235    uevent->path = "";
236    uevent->subsystem = "";
237    uevent->firmware = "";
238    uevent->major = -1;
239    uevent->minor = -1;
240    uevent->partition_name = NULL;
241    uevent->partition_num = -1;
242
243        /* currently ignoring SEQNUM */
244    while(*msg) {
245        if(!strncmp(msg, "ACTION=", 7)) {
246            msg += 7;
247            uevent->action = msg;
248        } else if(!strncmp(msg, "DEVPATH=", 8)) {
249            msg += 8;
250            uevent->path = msg;
251        } else if(!strncmp(msg, "SUBSYSTEM=", 10)) {
252            msg += 10;
253            uevent->subsystem = msg;
254        } else if(!strncmp(msg, "FIRMWARE=", 9)) {
255            msg += 9;
256            uevent->firmware = msg;
257        } else if(!strncmp(msg, "MAJOR=", 6)) {
258            msg += 6;
259            uevent->major = atoi(msg);
260        } else if(!strncmp(msg, "MINOR=", 6)) {
261            msg += 6;
262            uevent->minor = atoi(msg);
263        } else if(!strncmp(msg, "PARTN=", 6)) {
264            msg += 6;
265            uevent->partition_num = atoi(msg);
266        } else if(!strncmp(msg, "PARTNAME=", 9)) {
267            msg += 9;
268            uevent->partition_name = msg;
269        }
270
271            /* advance to after the next \0 */
272        while(*msg++)
273            ;
274    }
275
276    log_event_print("event { '%s', '%s', '%s', '%s', %d, %d }\n",
277                    uevent->action, uevent->path, uevent->subsystem,
278                    uevent->firmware, uevent->major, uevent->minor);
279}
280
281static char **get_character_device_symlinks(struct uevent *uevent)
282{
283    const char *parent;
284    char *slash;
285    char **links;
286    int link_num = 0;
287    int width;
288
289    if (strncmp(uevent->path, "/devices/platform/", 18))
290        return NULL;
291
292    links = malloc(sizeof(char *) * 2);
293    if (!links)
294        return NULL;
295    memset(links, 0, sizeof(char *) * 2);
296
297    /* skip "/devices/platform/<driver>" */
298    parent = strchr(uevent->path + 18, '/');
299    if (!*parent)
300        goto err;
301
302    if (!strncmp(parent, "/usb", 4)) {
303        /* skip root hub name and device. use device interface */
304        while (*++parent && *parent != '/');
305        if (*parent)
306            while (*++parent && *parent != '/');
307        if (!*parent)
308            goto err;
309        slash = strchr(++parent, '/');
310        if (!slash)
311            goto err;
312        width = slash - parent;
313        if (width <= 0)
314            goto err;
315
316        if (asprintf(&links[link_num], "/dev/usb/%s%.*s", uevent->subsystem, width, parent) > 0)
317            link_num++;
318        else
319            links[link_num] = NULL;
320        mkdir("/dev/usb", 0755);
321    }
322    else {
323        goto err;
324    }
325
326    return links;
327err:
328    free(links);
329    return NULL;
330}
331
332static char **parse_platform_block_device(struct uevent *uevent)
333{
334    const char *driver;
335    const char *path;
336    char *slash;
337    int width;
338    char buf[256];
339    char link_path[256];
340    int fd;
341    int link_num = 0;
342    int ret;
343    char *p;
344    unsigned int size;
345    struct stat info;
346
347    char **links = malloc(sizeof(char *) * 4);
348    if (!links)
349        return NULL;
350    memset(links, 0, sizeof(char *) * 4);
351
352    /* Drop "/devices/platform/" */
353    path = uevent->path;
354    driver = path + 18;
355    slash = strchr(driver, '/');
356    if (!slash)
357        goto err;
358    width = slash - driver;
359    if (width <= 0)
360        goto err;
361
362    snprintf(link_path, sizeof(link_path), "/dev/block/platform/%.*s",
363             width, driver);
364
365    if (uevent->partition_name) {
366        p = strdup(uevent->partition_name);
367        sanitize(p);
368        if (asprintf(&links[link_num], "%s/by-name/%s", link_path, p) > 0)
369            link_num++;
370        else
371            links[link_num] = NULL;
372        free(p);
373    }
374
375    if (uevent->partition_num >= 0) {
376        if (asprintf(&links[link_num], "%s/by-num/p%d", link_path, uevent->partition_num) > 0)
377            link_num++;
378        else
379            links[link_num] = NULL;
380    }
381
382    slash = strrchr(path, '/');
383    if (asprintf(&links[link_num], "%s/%s", link_path, slash + 1) > 0)
384        link_num++;
385    else
386        links[link_num] = NULL;
387
388    return links;
389
390err:
391    free(links);
392    return NULL;
393}
394
395static void handle_device_event(struct uevent *uevent)
396{
397    char devpath[96];
398    int devpath_ready = 0;
399    char *base, *name;
400    char **links = NULL;
401    int block;
402    int i;
403
404    if (!strcmp(uevent->action,"add"))
405        fixup_sys_perms(uevent->path);
406
407        /* if it's not a /dev device, nothing else to do */
408    if((uevent->major < 0) || (uevent->minor < 0))
409        return;
410
411        /* do we have a name? */
412    name = strrchr(uevent->path, '/');
413    if(!name)
414        return;
415    name++;
416
417        /* too-long names would overrun our buffer */
418    if(strlen(name) > 64)
419        return;
420
421        /* are we block or char? where should we live? */
422    if(!strncmp(uevent->subsystem, "block", 5)) {
423        block = 1;
424        base = "/dev/block/";
425        mkdir(base, 0755);
426        if (!strncmp(uevent->path, "/devices/platform/", 18))
427            links = parse_platform_block_device(uevent);
428    } else {
429        block = 0;
430            /* this should probably be configurable somehow */
431        if (!strncmp(uevent->subsystem, "usb", 3)) {
432            if (!strcmp(uevent->subsystem, "usb")) {
433                /* This imitates the file system that would be created
434                 * if we were using devfs instead.
435                 * Minors are broken up into groups of 128, starting at "001"
436                 */
437                int bus_id = uevent->minor / 128 + 1;
438                int device_id = uevent->minor % 128 + 1;
439                /* build directories */
440                mkdir("/dev/bus", 0755);
441                mkdir("/dev/bus/usb", 0755);
442                snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d", bus_id);
443                mkdir(devpath, 0755);
444                snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d/%03d", bus_id, device_id);
445                devpath_ready = 1;
446            } else {
447                /* ignore other USB events */
448                return;
449            }
450        } else if (!strncmp(uevent->subsystem, "graphics", 8)) {
451            base = "/dev/graphics/";
452            mkdir(base, 0755);
453        } else if (!strncmp(uevent->subsystem, "oncrpc", 6)) {
454            base = "/dev/oncrpc/";
455            mkdir(base, 0755);
456        } else if (!strncmp(uevent->subsystem, "adsp", 4)) {
457            base = "/dev/adsp/";
458            mkdir(base, 0755);
459        } else if (!strncmp(uevent->subsystem, "msm_camera", 10)) {
460            base = "/dev/msm_camera/";
461            mkdir(base, 0755);
462        } else if(!strncmp(uevent->subsystem, "input", 5)) {
463            base = "/dev/input/";
464            mkdir(base, 0755);
465        } else if(!strncmp(uevent->subsystem, "mtd", 3)) {
466            base = "/dev/mtd/";
467            mkdir(base, 0755);
468        } else if(!strncmp(uevent->subsystem, "sound", 5)) {
469            base = "/dev/snd/";
470            mkdir(base, 0755);
471        } else if(!strncmp(uevent->subsystem, "misc", 4) &&
472                    !strncmp(name, "log_", 4)) {
473            base = "/dev/log/";
474            mkdir(base, 0755);
475            name += 4;
476        } else
477            base = "/dev/";
478        links = get_character_device_symlinks(uevent);
479    }
480
481    if (!devpath_ready)
482        snprintf(devpath, sizeof(devpath), "%s%s", base, name);
483
484    if(!strcmp(uevent->action, "add")) {
485        make_device(devpath, uevent->path, block, uevent->major, uevent->minor);
486        if (links) {
487            for (i = 0; links[i]; i++)
488                make_link(devpath, links[i]);
489        }
490    }
491
492    if(!strcmp(uevent->action, "remove")) {
493        if (links) {
494            for (i = 0; links[i]; i++)
495                remove_link(devpath, links[i]);
496        }
497        unlink(devpath);
498    }
499
500    if (links) {
501        for (i = 0; links[i]; i++)
502            free(links[i]);
503        free(links);
504    }
505}
506
507static int load_firmware(int fw_fd, int loading_fd, int data_fd)
508{
509    struct stat st;
510    long len_to_copy;
511    int ret = 0;
512
513    if(fstat(fw_fd, &st) < 0)
514        return -1;
515    len_to_copy = st.st_size;
516
517    write(loading_fd, "1", 1);  /* start transfer */
518
519    while (len_to_copy > 0) {
520        char buf[PAGE_SIZE];
521        ssize_t nr;
522
523        nr = read(fw_fd, buf, sizeof(buf));
524        if(!nr)
525            break;
526        if(nr < 0) {
527            ret = -1;
528            break;
529        }
530
531        len_to_copy -= nr;
532        while (nr > 0) {
533            ssize_t nw = 0;
534
535            nw = write(data_fd, buf + nw, nr);
536            if(nw <= 0) {
537                ret = -1;
538                goto out;
539            }
540            nr -= nw;
541        }
542    }
543
544out:
545    if(!ret)
546        write(loading_fd, "0", 1);  /* successful end of transfer */
547    else
548        write(loading_fd, "-1", 2); /* abort transfer */
549
550    return ret;
551}
552
553static void process_firmware_event(struct uevent *uevent)
554{
555    char *root, *loading, *data, *file1 = NULL, *file2 = NULL;
556    int l, loading_fd, data_fd, fw_fd;
557
558    log_event_print("firmware event { '%s', '%s' }\n",
559                    uevent->path, uevent->firmware);
560
561    l = asprintf(&root, SYSFS_PREFIX"%s/", uevent->path);
562    if (l == -1)
563        return;
564
565    l = asprintf(&loading, "%sloading", root);
566    if (l == -1)
567        goto root_free_out;
568
569    l = asprintf(&data, "%sdata", root);
570    if (l == -1)
571        goto loading_free_out;
572
573    l = asprintf(&file1, FIRMWARE_DIR1"/%s", uevent->firmware);
574    if (l == -1)
575        goto data_free_out;
576
577    l = asprintf(&file2, FIRMWARE_DIR2"/%s", uevent->firmware);
578    if (l == -1)
579        goto data_free_out;
580
581    loading_fd = open(loading, O_WRONLY);
582    if(loading_fd < 0)
583        goto file_free_out;
584
585    data_fd = open(data, O_WRONLY);
586    if(data_fd < 0)
587        goto loading_close_out;
588
589    fw_fd = open(file1, O_RDONLY);
590    if(fw_fd < 0) {
591        fw_fd = open(file2, O_RDONLY);
592        if(fw_fd < 0)
593            goto data_close_out;
594    }
595
596    if(!load_firmware(fw_fd, loading_fd, data_fd))
597        log_event_print("firmware copy success { '%s', '%s' }\n", root, uevent->firmware);
598    else
599        log_event_print("firmware copy failure { '%s', '%s' }\n", root, uevent->firmware);
600
601    close(fw_fd);
602data_close_out:
603    close(data_fd);
604loading_close_out:
605    close(loading_fd);
606file_free_out:
607    free(file1);
608    free(file2);
609data_free_out:
610    free(data);
611loading_free_out:
612    free(loading);
613root_free_out:
614    free(root);
615}
616
617static void handle_firmware_event(struct uevent *uevent)
618{
619    pid_t pid;
620    int status;
621    int ret;
622
623    if(strcmp(uevent->subsystem, "firmware"))
624        return;
625
626    if(strcmp(uevent->action, "add"))
627        return;
628
629    /* we fork, to avoid making large memory allocations in init proper */
630    pid = fork();
631    if (!pid) {
632        process_firmware_event(uevent);
633        exit(EXIT_SUCCESS);
634    } else {
635        do {
636            ret = waitpid(pid, &status, 0);
637        } while (ret == -1 && errno == EINTR);
638    }
639}
640
641#define UEVENT_MSG_LEN  1024
642void handle_device_fd()
643{
644    for(;;) {
645        char msg[UEVENT_MSG_LEN+2];
646        char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
647        struct iovec iov = {msg, sizeof(msg)};
648        struct sockaddr_nl snl;
649        struct msghdr hdr = {&snl, sizeof(snl), &iov, 1, cred_msg, sizeof(cred_msg), 0};
650
651        ssize_t n = recvmsg(device_fd, &hdr, 0);
652        if (n <= 0) {
653            break;
654        }
655
656        if ((snl.nl_groups != 1) || (snl.nl_pid != 0)) {
657            /* ignoring non-kernel netlink multicast message */
658            continue;
659        }
660
661        struct cmsghdr * cmsg = CMSG_FIRSTHDR(&hdr);
662        if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
663            /* no sender credentials received, ignore message */
664            continue;
665        }
666
667        struct ucred * cred = (struct ucred *)CMSG_DATA(cmsg);
668        if (cred->uid != 0) {
669            /* message from non-root user, ignore */
670            continue;
671        }
672
673        if(n >= UEVENT_MSG_LEN)   /* overflow -- discard */
674            continue;
675
676        msg[n] = '\0';
677        msg[n+1] = '\0';
678
679        struct uevent uevent;
680        parse_event(msg, &uevent);
681
682        handle_device_event(&uevent);
683        handle_firmware_event(&uevent);
684    }
685}
686
687/* Coldboot walks parts of the /sys tree and pokes the uevent files
688** to cause the kernel to regenerate device add events that happened
689** before init's device manager was started
690**
691** We drain any pending events from the netlink socket every time
692** we poke another uevent file to make sure we don't overrun the
693** socket's buffer.
694*/
695
696static void do_coldboot(DIR *d)
697{
698    struct dirent *de;
699    int dfd, fd;
700
701    dfd = dirfd(d);
702
703    fd = openat(dfd, "uevent", O_WRONLY);
704    if(fd >= 0) {
705        write(fd, "add\n", 4);
706        close(fd);
707        handle_device_fd();
708    }
709
710    while((de = readdir(d))) {
711        DIR *d2;
712
713        if(de->d_type != DT_DIR || de->d_name[0] == '.')
714            continue;
715
716        fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
717        if(fd < 0)
718            continue;
719
720        d2 = fdopendir(fd);
721        if(d2 == 0)
722            close(fd);
723        else {
724            do_coldboot(d2);
725            closedir(d2);
726        }
727    }
728}
729
730static void coldboot(const char *path)
731{
732    DIR *d = opendir(path);
733    if(d) {
734        do_coldboot(d);
735        closedir(d);
736    }
737}
738
739void device_init(void)
740{
741    suseconds_t t0, t1;
742    struct stat info;
743    int fd;
744
745    device_fd = open_uevent_socket();
746    if(device_fd < 0)
747        return;
748
749    fcntl(device_fd, F_SETFD, FD_CLOEXEC);
750    fcntl(device_fd, F_SETFL, O_NONBLOCK);
751
752    if (stat(coldboot_done, &info) < 0) {
753        t0 = get_usecs();
754        coldboot("/sys/class");
755        coldboot("/sys/block");
756        coldboot("/sys/devices");
757        t1 = get_usecs();
758        fd = open(coldboot_done, O_WRONLY|O_CREAT, 0000);
759        close(fd);
760        log_event_print("coldboot %ld uS\n", ((long) (t1 - t0)));
761    } else {
762        log_event_print("skipping coldboot, already done\n");
763    }
764}
765
766int get_device_fd()
767{
768    return device_fd;
769}
770