devices.c revision de35f2741c4e32e331a92be99f7c04b92b94beb2 
1/*
2 * Copyright (C) 2007 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <errno.h>
18#include <stddef.h>
19#include <stdio.h>
20#include <stdlib.h>
21#include <sys/stat.h>
22#include <sys/types.h>
23
24#include <fcntl.h>
25#include <dirent.h>
26#include <unistd.h>
27#include <string.h>
28
29#include <sys/socket.h>
30#include <sys/un.h>
31#include <linux/netlink.h>
32#include <private/android_filesystem_config.h>
33#include <sys/time.h>
34#include <asm/page.h>
35#include <sys/wait.h>
36
37#include "devices.h"
38#include "util.h"
39#include "log.h"
40#include "list.h"
41
42#define SYSFS_PREFIX    "/sys"
43#define FIRMWARE_DIR1   "/etc/firmware"
44#define FIRMWARE_DIR2   "/vendor/firmware"
45
46static int device_fd = -1;
47
48struct uevent {
49    const char *action;
50    const char *path;
51    const char *subsystem;
52    const char *firmware;
53    const char *partition_name;
54    int partition_num;
55    int major;
56    int minor;
57};
58
59static int open_uevent_socket(void)
60{
61    struct sockaddr_nl addr;
62    int sz = 64*1024; // XXX larger? udev uses 16MB!
63    int on = 1;
64    int s;
65
66    memset(&addr, 0, sizeof(addr));
67    addr.nl_family = AF_NETLINK;
68    addr.nl_pid = getpid();
69    addr.nl_groups = 0xffffffff;
70
71    s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
72    if(s < 0)
73        return -1;
74
75    setsockopt(s, SOL_SOCKET, SO_RCVBUFFORCE, &sz, sizeof(sz));
76    setsockopt(s, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
77
78    if(bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
79        close(s);
80        return -1;
81    }
82
83    return s;
84}
85
86struct perms_ {
87    char *name;
88    char *attr;
89    mode_t perm;
90    unsigned int uid;
91    unsigned int gid;
92    unsigned short prefix;
93};
94
95struct perm_node {
96    struct perms_ dp;
97    struct listnode plist;
98};
99
100static list_declare(sys_perms);
101static list_declare(dev_perms);
102
103int add_dev_perms(const char *name, const char *attr,
104                  mode_t perm, unsigned int uid, unsigned int gid,
105                  unsigned short prefix) {
106    struct perm_node *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
125    if (attr)
126        list_add_tail(&sys_perms, &node->plist);
127    else
128        list_add_tail(&dev_perms, &node->plist);
129
130    return 0;
131}
132
133void fixup_sys_perms(const char *upath)
134{
135    char buf[512];
136    struct listnode *node;
137    struct perms_ *dp;
138
139        /* upaths omit the "/sys" that paths in this list
140         * contain, so we add 4 when comparing...
141         */
142    list_for_each(node, &sys_perms) {
143        dp = &(node_to_item(node, struct perm_node, plist))->dp;
144        if (dp->prefix) {
145            if (strncmp(upath, dp->name + 4, strlen(dp->name + 4)))
146                continue;
147        } else {
148            if (strcmp(upath, dp->name + 4))
149                continue;
150        }
151
152        if ((strlen(upath) + strlen(dp->attr) + 6) > sizeof(buf))
153            return;
154
155        sprintf(buf,"/sys%s/%s", upath, dp->attr);
156        INFO("fixup %s %d %d 0%o\n", buf, dp->uid, dp->gid, dp->perm);
157        chown(buf, dp->uid, dp->gid);
158        chmod(buf, dp->perm);
159    }
160}
161
162static mode_t get_device_perm(const char *path, unsigned *uid, unsigned *gid)
163{
164    mode_t perm;
165    struct listnode *node;
166    struct perm_node *perm_node;
167    struct perms_ *dp;
168
169    /* search the perms list in reverse so that ueventd.$hardware can
170     * override ueventd.rc
171     */
172    list_for_each_reverse(node, &dev_perms) {
173        perm_node = node_to_item(node, struct perm_node, plist);
174        dp = &perm_node->dp;
175
176        if (dp->prefix) {
177            if (strncmp(path, dp->name, strlen(dp->name)))
178                continue;
179        } else {
180            if (strcmp(path, dp->name))
181                continue;
182        }
183        *uid = dp->uid;
184        *gid = dp->gid;
185        return dp->perm;
186    }
187    /* Default if nothing found. */
188    *uid = 0;
189    *gid = 0;
190    return 0600;
191}
192
193static void make_device(const char *path,
194                        const char *upath,
195                        int block, int major, int minor)
196{
197    unsigned uid;
198    unsigned gid;
199    mode_t mode;
200    dev_t dev;
201
202    mode = get_device_perm(path, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
203    dev = makedev(major, minor);
204    /* Temporarily change egid to avoid race condition setting the gid of the
205     * device node. Unforunately changing the euid would prevent creation of
206     * some device nodes, so the uid has to be set with chown() and is still
207     * racy. Fixing the gid race at least fixed the issue with system_server
208     * opening dynamic input devices under the AID_INPUT gid. */
209    setegid(gid);
210    mknod(path, mode, dev);
211    chown(path, uid, -1);
212    setegid(AID_ROOT);
213}
214
215#if LOG_UEVENTS
216
217static inline suseconds_t get_usecs(void)
218{
219    struct timeval tv;
220    gettimeofday(&tv, 0);
221    return tv.tv_sec * (suseconds_t) 1000000 + tv.tv_usec;
222}
223
224#define log_event_print(x...) INFO(x)
225
226#else
227
228#define log_event_print(fmt, args...)   do { } while (0)
229#define get_usecs()                     0
230
231#endif
232
233static void parse_event(const char *msg, struct uevent *uevent)
234{
235    uevent->action = "";
236    uevent->path = "";
237    uevent->subsystem = "";
238    uevent->firmware = "";
239    uevent->major = -1;
240    uevent->minor = -1;
241    uevent->partition_name = NULL;
242    uevent->partition_num = -1;
243
244        /* currently ignoring SEQNUM */
245    while(*msg) {
246        if(!strncmp(msg, "ACTION=", 7)) {
247            msg += 7;
248            uevent->action = msg;
249        } else if(!strncmp(msg, "DEVPATH=", 8)) {
250            msg += 8;
251            uevent->path = msg;
252        } else if(!strncmp(msg, "SUBSYSTEM=", 10)) {
253            msg += 10;
254            uevent->subsystem = msg;
255        } else if(!strncmp(msg, "FIRMWARE=", 9)) {
256            msg += 9;
257            uevent->firmware = msg;
258        } else if(!strncmp(msg, "MAJOR=", 6)) {
259            msg += 6;
260            uevent->major = atoi(msg);
261        } else if(!strncmp(msg, "MINOR=", 6)) {
262            msg += 6;
263            uevent->minor = atoi(msg);
264        } else if(!strncmp(msg, "PARTN=", 6)) {
265            msg += 6;
266            uevent->partition_num = atoi(msg);
267        } else if(!strncmp(msg, "PARTNAME=", 9)) {
268            msg += 9;
269            uevent->partition_name = msg;
270        }
271
272            /* advance to after the next \0 */
273        while(*msg++)
274            ;
275    }
276
277    log_event_print("event { '%s', '%s', '%s', '%s', %d, %d }\n",
278                    uevent->action, uevent->path, uevent->subsystem,
279                    uevent->firmware, uevent->major, uevent->minor);
280}
281
282static char **get_character_device_symlinks(struct uevent *uevent)
283{
284    const char *parent;
285    char *slash;
286    char **links;
287    int link_num = 0;
288    int width;
289
290    if (strncmp(uevent->path, "/devices/platform/", 18))
291        return NULL;
292
293    links = malloc(sizeof(char *) * 2);
294    if (!links)
295        return NULL;
296    memset(links, 0, sizeof(char *) * 2);
297
298    /* skip "/devices/platform/<driver>" */
299    parent = strchr(uevent->path + 18, '/');
300    if (!*parent)
301        goto err;
302
303    if (!strncmp(parent, "/usb", 4)) {
304        /* skip root hub name and device. use device interface */
305        while (*++parent && *parent != '/');
306        if (*parent)
307            while (*++parent && *parent != '/');
308        if (!*parent)
309            goto err;
310        slash = strchr(++parent, '/');
311        if (!slash)
312            goto err;
313        width = slash - parent;
314        if (width <= 0)
315            goto err;
316
317        if (asprintf(&links[link_num], "/dev/usb/%s%.*s", uevent->subsystem, width, parent) > 0)
318            link_num++;
319        else
320            links[link_num] = NULL;
321        mkdir("/dev/usb", 0755);
322    }
323    else {
324        goto err;
325    }
326
327    return links;
328err:
329    free(links);
330    return NULL;
331}
332
333static char **parse_platform_block_device(struct uevent *uevent)
334{
335    const char *driver;
336    const char *path;
337    char *slash;
338    int width;
339    char buf[256];
340    char link_path[256];
341    int fd;
342    int link_num = 0;
343    int ret;
344    char *p;
345    unsigned int size;
346    struct stat info;
347
348    char **links = malloc(sizeof(char *) * 4);
349    if (!links)
350        return NULL;
351    memset(links, 0, sizeof(char *) * 4);
352
353    /* Drop "/devices/platform/" */
354    path = uevent->path;
355    driver = path + 18;
356    slash = strchr(driver, '/');
357    if (!slash)
358        goto err;
359    width = slash - driver;
360    if (width <= 0)
361        goto err;
362
363    snprintf(link_path, sizeof(link_path), "/dev/block/platform/%.*s",
364             width, driver);
365
366    if (uevent->partition_name) {
367        p = strdup(uevent->partition_name);
368        sanitize(p);
369        if (asprintf(&links[link_num], "%s/by-name/%s", link_path, p) > 0)
370            link_num++;
371        else
372            links[link_num] = NULL;
373        free(p);
374    }
375
376    if (uevent->partition_num >= 0) {
377        if (asprintf(&links[link_num], "%s/by-num/p%d", link_path, uevent->partition_num) > 0)
378            link_num++;
379        else
380            links[link_num] = NULL;
381    }
382
383    slash = strrchr(path, '/');
384    if (asprintf(&links[link_num], "%s/%s", link_path, slash + 1) > 0)
385        link_num++;
386    else
387        links[link_num] = NULL;
388
389    return links;
390
391err:
392    free(links);
393    return NULL;
394}
395
396static void handle_device_event(struct uevent *uevent)
397{
398    char devpath[96];
399    int devpath_ready = 0;
400    char *base, *name;
401    char **links = NULL;
402    int block;
403    int i;
404
405    if (!strcmp(uevent->action,"add"))
406        fixup_sys_perms(uevent->path);
407
408        /* if it's not a /dev device, nothing else to do */
409    if((uevent->major < 0) || (uevent->minor < 0))
410        return;
411
412        /* do we have a name? */
413    name = strrchr(uevent->path, '/');
414    if(!name)
415        return;
416    name++;
417
418        /* too-long names would overrun our buffer */
419    if(strlen(name) > 64)
420        return;
421
422        /* are we block or char? where should we live? */
423    if(!strncmp(uevent->subsystem, "block", 5)) {
424        block = 1;
425        base = "/dev/block/";
426        mkdir(base, 0755);
427        if (!strncmp(uevent->path, "/devices/platform/", 18))
428            links = parse_platform_block_device(uevent);
429    } else {
430        block = 0;
431            /* this should probably be configurable somehow */
432        if (!strncmp(uevent->subsystem, "usb", 3)) {
433            if (!strcmp(uevent->subsystem, "usb")) {
434                /* This imitates the file system that would be created
435                 * if we were using devfs instead.
436                 * Minors are broken up into groups of 128, starting at "001"
437                 */
438                int bus_id = uevent->minor / 128 + 1;
439                int device_id = uevent->minor % 128 + 1;
440                /* build directories */
441                mkdir("/dev/bus", 0755);
442                mkdir("/dev/bus/usb", 0755);
443                snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d", bus_id);
444                mkdir(devpath, 0755);
445                snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d/%03d", bus_id, device_id);
446                devpath_ready = 1;
447            } else {
448                /* ignore other USB events */
449                return;
450            }
451        } else if (!strncmp(uevent->subsystem, "graphics", 8)) {
452            base = "/dev/graphics/";
453            mkdir(base, 0755);
454        } else if (!strncmp(uevent->subsystem, "oncrpc", 6)) {
455            base = "/dev/oncrpc/";
456            mkdir(base, 0755);
457        } else if (!strncmp(uevent->subsystem, "adsp", 4)) {
458            base = "/dev/adsp/";
459            mkdir(base, 0755);
460        } else if (!strncmp(uevent->subsystem, "msm_camera", 10)) {
461            base = "/dev/msm_camera/";
462            mkdir(base, 0755);
463        } else if(!strncmp(uevent->subsystem, "input", 5)) {
464            base = "/dev/input/";
465            mkdir(base, 0755);
466        } else if(!strncmp(uevent->subsystem, "mtd", 3)) {
467            base = "/dev/mtd/";
468            mkdir(base, 0755);
469        } else if(!strncmp(uevent->subsystem, "sound", 5)) {
470            base = "/dev/snd/";
471            mkdir(base, 0755);
472        } else if(!strncmp(uevent->subsystem, "misc", 4) &&
473                    !strncmp(name, "log_", 4)) {
474            base = "/dev/log/";
475            mkdir(base, 0755);
476            name += 4;
477        } else
478            base = "/dev/";
479        links = get_character_device_symlinks(uevent);
480    }
481
482    if (!devpath_ready)
483        snprintf(devpath, sizeof(devpath), "%s%s", base, name);
484
485    if(!strcmp(uevent->action, "add")) {
486        make_device(devpath, uevent->path, block, uevent->major, uevent->minor);
487        if (links) {
488            for (i = 0; links[i]; i++)
489                make_link(devpath, links[i]);
490        }
491    }
492
493    if(!strcmp(uevent->action, "remove")) {
494        if (links) {
495            for (i = 0; links[i]; i++)
496                remove_link(devpath, links[i]);
497        }
498        unlink(devpath);
499    }
500
501    if (links) {
502        for (i = 0; links[i]; i++)
503            free(links[i]);
504        free(links);
505    }
506}
507
508static int load_firmware(int fw_fd, int loading_fd, int data_fd)
509{
510    struct stat st;
511    long len_to_copy;
512    int ret = 0;
513
514    if(fstat(fw_fd, &st) < 0)
515        return -1;
516    len_to_copy = st.st_size;
517
518    write(loading_fd, "1", 1);  /* start transfer */
519
520    while (len_to_copy > 0) {
521        char buf[PAGE_SIZE];
522        ssize_t nr;
523
524        nr = read(fw_fd, buf, sizeof(buf));
525        if(!nr)
526            break;
527        if(nr < 0) {
528            ret = -1;
529            break;
530        }
531
532        len_to_copy -= nr;
533        while (nr > 0) {
534            ssize_t nw = 0;
535
536            nw = write(data_fd, buf + nw, nr);
537            if(nw <= 0) {
538                ret = -1;
539                goto out;
540            }
541            nr -= nw;
542        }
543    }
544
545out:
546    if(!ret)
547        write(loading_fd, "0", 1);  /* successful end of transfer */
548    else
549        write(loading_fd, "-1", 2); /* abort transfer */
550
551    return ret;
552}
553
554static void process_firmware_event(struct uevent *uevent)
555{
556    char *root, *loading, *data, *file1 = NULL, *file2 = NULL;
557    int l, loading_fd, data_fd, fw_fd;
558
559    log_event_print("firmware event { '%s', '%s' }\n",
560                    uevent->path, uevent->firmware);
561
562    l = asprintf(&root, SYSFS_PREFIX"%s/", uevent->path);
563    if (l == -1)
564        return;
565
566    l = asprintf(&loading, "%sloading", root);
567    if (l == -1)
568        goto root_free_out;
569
570    l = asprintf(&data, "%sdata", root);
571    if (l == -1)
572        goto loading_free_out;
573
574    l = asprintf(&file1, FIRMWARE_DIR1"/%s", uevent->firmware);
575    if (l == -1)
576        goto data_free_out;
577
578    l = asprintf(&file2, FIRMWARE_DIR2"/%s", uevent->firmware);
579    if (l == -1)
580        goto data_free_out;
581
582    loading_fd = open(loading, O_WRONLY);
583    if(loading_fd < 0)
584        goto file_free_out;
585
586    data_fd = open(data, O_WRONLY);
587    if(data_fd < 0)
588        goto loading_close_out;
589
590    fw_fd = open(file1, O_RDONLY);
591    if(fw_fd < 0) {
592        fw_fd = open(file2, O_RDONLY);
593        if (fw_fd < 0) {
594            write(loading_fd, "-1", 2);
595            goto data_close_out;
596        }
597    }
598
599    if(!load_firmware(fw_fd, loading_fd, data_fd))
600        log_event_print("firmware copy success { '%s', '%s' }\n", root, uevent->firmware);
601    else
602        log_event_print("firmware copy failure { '%s', '%s' }\n", root, uevent->firmware);
603
604    close(fw_fd);
605data_close_out:
606    close(data_fd);
607loading_close_out:
608    close(loading_fd);
609file_free_out:
610    free(file1);
611    free(file2);
612data_free_out:
613    free(data);
614loading_free_out:
615    free(loading);
616root_free_out:
617    free(root);
618}
619
620static void handle_firmware_event(struct uevent *uevent)
621{
622    pid_t pid;
623    int status;
624    int ret;
625
626    if(strcmp(uevent->subsystem, "firmware"))
627        return;
628
629    if(strcmp(uevent->action, "add"))
630        return;
631
632    /* we fork, to avoid making large memory allocations in init proper */
633    pid = fork();
634    if (!pid) {
635        process_firmware_event(uevent);
636        exit(EXIT_SUCCESS);
637    } else {
638        do {
639            ret = waitpid(pid, &status, 0);
640        } while (ret == -1 && errno == EINTR);
641    }
642}
643
644#define UEVENT_MSG_LEN  1024
645void handle_device_fd()
646{
647    for(;;) {
648        char msg[UEVENT_MSG_LEN+2];
649        char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
650        struct iovec iov = {msg, sizeof(msg)};
651        struct sockaddr_nl snl;
652        struct msghdr hdr = {&snl, sizeof(snl), &iov, 1, cred_msg, sizeof(cred_msg), 0};
653
654        ssize_t n = recvmsg(device_fd, &hdr, 0);
655        if (n <= 0) {
656            break;
657        }
658
659        if ((snl.nl_groups != 1) || (snl.nl_pid != 0)) {
660            /* ignoring non-kernel netlink multicast message */
661            continue;
662        }
663
664        struct cmsghdr * cmsg = CMSG_FIRSTHDR(&hdr);
665        if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
666            /* no sender credentials received, ignore message */
667            continue;
668        }
669
670        struct ucred * cred = (struct ucred *)CMSG_DATA(cmsg);
671        if (cred->uid != 0) {
672            /* message from non-root user, ignore */
673            continue;
674        }
675
676        if(n >= UEVENT_MSG_LEN)   /* overflow -- discard */
677            continue;
678
679        msg[n] = '\0';
680        msg[n+1] = '\0';
681
682        struct uevent uevent;
683        parse_event(msg, &uevent);
684
685        handle_device_event(&uevent);
686        handle_firmware_event(&uevent);
687    }
688}
689
690/* Coldboot walks parts of the /sys tree and pokes the uevent files
691** to cause the kernel to regenerate device add events that happened
692** before init's device manager was started
693**
694** We drain any pending events from the netlink socket every time
695** we poke another uevent file to make sure we don't overrun the
696** socket's buffer.
697*/
698
699static void do_coldboot(DIR *d)
700{
701    struct dirent *de;
702    int dfd, fd;
703
704    dfd = dirfd(d);
705
706    fd = openat(dfd, "uevent", O_WRONLY);
707    if(fd >= 0) {
708        write(fd, "add\n", 4);
709        close(fd);
710        handle_device_fd();
711    }
712
713    while((de = readdir(d))) {
714        DIR *d2;
715
716        if(de->d_type != DT_DIR || de->d_name[0] == '.')
717            continue;
718
719        fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
720        if(fd < 0)
721            continue;
722
723        d2 = fdopendir(fd);
724        if(d2 == 0)
725            close(fd);
726        else {
727            do_coldboot(d2);
728            closedir(d2);
729        }
730    }
731}
732
733static void coldboot(const char *path)
734{
735    DIR *d = opendir(path);
736    if(d) {
737        do_coldboot(d);
738        closedir(d);
739    }
740}
741
742void device_init(void)
743{
744    suseconds_t t0, t1;
745    struct stat info;
746    int fd;
747
748    device_fd = open_uevent_socket();
749    if(device_fd < 0)
750        return;
751
752    fcntl(device_fd, F_SETFD, FD_CLOEXEC);
753    fcntl(device_fd, F_SETFL, O_NONBLOCK);
754
755    if (stat(coldboot_done, &info) < 0) {
756        t0 = get_usecs();
757        coldboot("/sys/class");
758        coldboot("/sys/block");
759        coldboot("/sys/devices");
760        t1 = get_usecs();
761        fd = open(coldboot_done, O_WRONLY|O_CREAT, 0000);
762        close(fd);
763        log_event_print("coldboot %ld uS\n", ((long) (t1 - t0)));
764    } else {
765        log_event_print("skipping coldboot, already done\n");
766    }
767}
768
769int get_device_fd()
770{
771    return device_fd;
772}
773