devices.c revision e3ab42457077ec2a66bac553e59a7fee08d4fa9e 
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 <cutils/uevent.h>
38
39#include "devices.h"
40#include "util.h"
41#include "log.h"
42#include "list.h"
43
44#define SYSFS_PREFIX    "/sys"
45#define FIRMWARE_DIR1   "/etc/firmware"
46#define FIRMWARE_DIR2   "/vendor/firmware"
47
48static int device_fd = -1;
49
50struct uevent {
51    const char *action;
52    const char *path;
53    const char *subsystem;
54    const char *firmware;
55    const char *partition_name;
56    int partition_num;
57    int major;
58    int minor;
59};
60
61static int open_uevent_socket(void)
62{
63    struct sockaddr_nl addr;
64    int sz = 64*1024; // XXX larger? udev uses 16MB!
65    int on = 1;
66    int s;
67
68    memset(&addr, 0, sizeof(addr));
69    addr.nl_family = AF_NETLINK;
70    addr.nl_pid = getpid();
71    addr.nl_groups = 0xffffffff;
72
73    s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
74    if(s < 0)
75        return -1;
76
77    setsockopt(s, SOL_SOCKET, SO_RCVBUFFORCE, &sz, sizeof(sz));
78    setsockopt(s, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
79
80    if(bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
81        close(s);
82        return -1;
83    }
84
85    return s;
86}
87
88struct perms_ {
89    char *name;
90    char *attr;
91    mode_t perm;
92    unsigned int uid;
93    unsigned int gid;
94    unsigned short prefix;
95};
96
97struct perm_node {
98    struct perms_ dp;
99    struct listnode plist;
100};
101
102static list_declare(sys_perms);
103static list_declare(dev_perms);
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    struct perm_node *node = calloc(1, sizeof(*node));
109    if (!node)
110        return -ENOMEM;
111
112    node->dp.name = strdup(name);
113    if (!node->dp.name)
114        return -ENOMEM;
115
116    if (attr) {
117        node->dp.attr = strdup(attr);
118        if (!node->dp.attr)
119            return -ENOMEM;
120    }
121
122    node->dp.perm = perm;
123    node->dp.uid = uid;
124    node->dp.gid = gid;
125    node->dp.prefix = prefix;
126
127    if (attr)
128        list_add_tail(&sys_perms, &node->plist);
129    else
130        list_add_tail(&dev_perms, &node->plist);
131
132    return 0;
133}
134
135void fixup_sys_perms(const char *upath)
136{
137    char buf[512];
138    struct listnode *node;
139    struct perms_ *dp;
140
141        /* upaths omit the "/sys" that paths in this list
142         * contain, so we add 4 when comparing...
143         */
144    list_for_each(node, &sys_perms) {
145        dp = &(node_to_item(node, struct perm_node, plist))->dp;
146        if (dp->prefix) {
147            if (strncmp(upath, dp->name + 4, strlen(dp->name + 4)))
148                continue;
149        } else {
150            if (strcmp(upath, dp->name + 4))
151                continue;
152        }
153
154        if ((strlen(upath) + strlen(dp->attr) + 6) > sizeof(buf))
155            return;
156
157        sprintf(buf,"/sys%s/%s", upath, dp->attr);
158        INFO("fixup %s %d %d 0%o\n", buf, dp->uid, dp->gid, dp->perm);
159        chown(buf, dp->uid, dp->gid);
160        chmod(buf, dp->perm);
161    }
162}
163
164static mode_t get_device_perm(const char *path, unsigned *uid, unsigned *gid)
165{
166    mode_t perm;
167    struct listnode *node;
168    struct perm_node *perm_node;
169    struct perms_ *dp;
170
171    /* search the perms list in reverse so that ueventd.$hardware can
172     * override ueventd.rc
173     */
174    list_for_each_reverse(node, &dev_perms) {
175        perm_node = node_to_item(node, struct perm_node, plist);
176        dp = &perm_node->dp;
177
178        if (dp->prefix) {
179            if (strncmp(path, dp->name, strlen(dp->name)))
180                continue;
181        } else {
182            if (strcmp(path, dp->name))
183                continue;
184        }
185        *uid = dp->uid;
186        *gid = dp->gid;
187        return dp->perm;
188    }
189    /* Default if nothing found. */
190    *uid = 0;
191    *gid = 0;
192    return 0600;
193}
194
195static void make_device(const char *path,
196                        const char *upath,
197                        int block, int major, int minor)
198{
199    unsigned uid;
200    unsigned gid;
201    mode_t mode;
202    dev_t dev;
203
204    mode = get_device_perm(path, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
205    dev = makedev(major, minor);
206    /* Temporarily change egid to avoid race condition setting the gid of the
207     * device node. Unforunately changing the euid would prevent creation of
208     * some device nodes, so the uid has to be set with chown() and is still
209     * racy. Fixing the gid race at least fixed the issue with system_server
210     * opening dynamic input devices under the AID_INPUT gid. */
211    setegid(gid);
212    mknod(path, mode, dev);
213    chown(path, uid, -1);
214    setegid(AID_ROOT);
215}
216
217#if LOG_UEVENTS
218
219static inline suseconds_t get_usecs(void)
220{
221    struct timeval tv;
222    gettimeofday(&tv, 0);
223    return tv.tv_sec * (suseconds_t) 1000000 + tv.tv_usec;
224}
225
226#define log_event_print(x...) INFO(x)
227
228#else
229
230#define log_event_print(fmt, args...)   do { } while (0)
231#define get_usecs()                     0
232
233#endif
234
235static void parse_event(const char *msg, struct uevent *uevent)
236{
237    uevent->action = "";
238    uevent->path = "";
239    uevent->subsystem = "";
240    uevent->firmware = "";
241    uevent->major = -1;
242    uevent->minor = -1;
243    uevent->partition_name = NULL;
244    uevent->partition_num = -1;
245
246        /* currently ignoring SEQNUM */
247    while(*msg) {
248        if(!strncmp(msg, "ACTION=", 7)) {
249            msg += 7;
250            uevent->action = msg;
251        } else if(!strncmp(msg, "DEVPATH=", 8)) {
252            msg += 8;
253            uevent->path = msg;
254        } else if(!strncmp(msg, "SUBSYSTEM=", 10)) {
255            msg += 10;
256            uevent->subsystem = msg;
257        } else if(!strncmp(msg, "FIRMWARE=", 9)) {
258            msg += 9;
259            uevent->firmware = msg;
260        } else if(!strncmp(msg, "MAJOR=", 6)) {
261            msg += 6;
262            uevent->major = atoi(msg);
263        } else if(!strncmp(msg, "MINOR=", 6)) {
264            msg += 6;
265            uevent->minor = atoi(msg);
266        } else if(!strncmp(msg, "PARTN=", 6)) {
267            msg += 6;
268            uevent->partition_num = atoi(msg);
269        } else if(!strncmp(msg, "PARTNAME=", 9)) {
270            msg += 9;
271            uevent->partition_name = msg;
272        }
273
274            /* advance to after the next \0 */
275        while(*msg++)
276            ;
277    }
278
279    log_event_print("event { '%s', '%s', '%s', '%s', %d, %d }\n",
280                    uevent->action, uevent->path, uevent->subsystem,
281                    uevent->firmware, uevent->major, uevent->minor);
282}
283
284static char **get_character_device_symlinks(struct uevent *uevent)
285{
286    const char *parent;
287    char *slash;
288    char **links;
289    int link_num = 0;
290    int width;
291
292    if (strncmp(uevent->path, "/devices/platform/", 18))
293        return NULL;
294
295    links = malloc(sizeof(char *) * 2);
296    if (!links)
297        return NULL;
298    memset(links, 0, sizeof(char *) * 2);
299
300    /* skip "/devices/platform/<driver>" */
301    parent = strchr(uevent->path + 18, '/');
302    if (!*parent)
303        goto err;
304
305    if (!strncmp(parent, "/usb", 4)) {
306        /* skip root hub name and device. use device interface */
307        while (*++parent && *parent != '/');
308        if (*parent)
309            while (*++parent && *parent != '/');
310        if (!*parent)
311            goto err;
312        slash = strchr(++parent, '/');
313        if (!slash)
314            goto err;
315        width = slash - parent;
316        if (width <= 0)
317            goto err;
318
319        if (asprintf(&links[link_num], "/dev/usb/%s%.*s", uevent->subsystem, width, parent) > 0)
320            link_num++;
321        else
322            links[link_num] = NULL;
323        mkdir("/dev/usb", 0755);
324    }
325    else {
326        goto err;
327    }
328
329    return links;
330err:
331    free(links);
332    return NULL;
333}
334
335static char **parse_platform_block_device(struct uevent *uevent)
336{
337    const char *driver;
338    const char *path;
339    char *slash;
340    int width;
341    char buf[256];
342    char link_path[256];
343    int fd;
344    int link_num = 0;
345    int ret;
346    char *p;
347    unsigned int size;
348    struct stat info;
349
350    char **links = malloc(sizeof(char *) * 4);
351    if (!links)
352        return NULL;
353    memset(links, 0, sizeof(char *) * 4);
354
355    /* Drop "/devices/platform/" */
356    path = uevent->path;
357    driver = path + 18;
358    slash = strchr(driver, '/');
359    if (!slash)
360        goto err;
361    width = slash - driver;
362    if (width <= 0)
363        goto err;
364
365    snprintf(link_path, sizeof(link_path), "/dev/block/platform/%.*s",
366             width, driver);
367
368    if (uevent->partition_name) {
369        p = strdup(uevent->partition_name);
370        sanitize(p);
371        if (asprintf(&links[link_num], "%s/by-name/%s", link_path, p) > 0)
372            link_num++;
373        else
374            links[link_num] = NULL;
375        free(p);
376    }
377
378    if (uevent->partition_num >= 0) {
379        if (asprintf(&links[link_num], "%s/by-num/p%d", link_path, uevent->partition_num) > 0)
380            link_num++;
381        else
382            links[link_num] = NULL;
383    }
384
385    slash = strrchr(path, '/');
386    if (asprintf(&links[link_num], "%s/%s", link_path, slash + 1) > 0)
387        link_num++;
388    else
389        links[link_num] = NULL;
390
391    return links;
392
393err:
394    free(links);
395    return NULL;
396}
397
398static void handle_device_event(struct uevent *uevent)
399{
400    char devpath[96];
401    int devpath_ready = 0;
402    char *base, *name;
403    char **links = NULL;
404    int block;
405    int i;
406
407    if (!strcmp(uevent->action,"add"))
408        fixup_sys_perms(uevent->path);
409
410        /* if it's not a /dev device, nothing else to do */
411    if((uevent->major < 0) || (uevent->minor < 0))
412        return;
413
414        /* do we have a name? */
415    name = strrchr(uevent->path, '/');
416    if(!name)
417        return;
418    name++;
419
420        /* too-long names would overrun our buffer */
421    if(strlen(name) > 64)
422        return;
423
424        /* are we block or char? where should we live? */
425    if(!strncmp(uevent->subsystem, "block", 5)) {
426        block = 1;
427        base = "/dev/block/";
428        mkdir(base, 0755);
429        if (!strncmp(uevent->path, "/devices/platform/", 18))
430            links = parse_platform_block_device(uevent);
431    } else {
432        block = 0;
433            /* this should probably be configurable somehow */
434        if (!strncmp(uevent->subsystem, "usb", 3)) {
435            if (!strcmp(uevent->subsystem, "usb")) {
436                /* This imitates the file system that would be created
437                 * if we were using devfs instead.
438                 * Minors are broken up into groups of 128, starting at "001"
439                 */
440                int bus_id = uevent->minor / 128 + 1;
441                int device_id = uevent->minor % 128 + 1;
442                /* build directories */
443                mkdir("/dev/bus", 0755);
444                mkdir("/dev/bus/usb", 0755);
445                snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d", bus_id);
446                mkdir(devpath, 0755);
447                snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d/%03d", bus_id, device_id);
448                devpath_ready = 1;
449            } else {
450                /* ignore other USB events */
451                return;
452            }
453        } else if (!strncmp(uevent->subsystem, "graphics", 8)) {
454            base = "/dev/graphics/";
455            mkdir(base, 0755);
456        } else if (!strncmp(uevent->subsystem, "oncrpc", 6)) {
457            base = "/dev/oncrpc/";
458            mkdir(base, 0755);
459        } else if (!strncmp(uevent->subsystem, "adsp", 4)) {
460            base = "/dev/adsp/";
461            mkdir(base, 0755);
462        } else if (!strncmp(uevent->subsystem, "msm_camera", 10)) {
463            base = "/dev/msm_camera/";
464            mkdir(base, 0755);
465        } else if(!strncmp(uevent->subsystem, "input", 5)) {
466            base = "/dev/input/";
467            mkdir(base, 0755);
468        } else if(!strncmp(uevent->subsystem, "mtd", 3)) {
469            base = "/dev/mtd/";
470            mkdir(base, 0755);
471        } else if(!strncmp(uevent->subsystem, "sound", 5)) {
472            base = "/dev/snd/";
473            mkdir(base, 0755);
474        } else if(!strncmp(uevent->subsystem, "misc", 4) &&
475                    !strncmp(name, "log_", 4)) {
476            base = "/dev/log/";
477            mkdir(base, 0755);
478            name += 4;
479        } else
480            base = "/dev/";
481        links = get_character_device_symlinks(uevent);
482    }
483
484    if (!devpath_ready)
485        snprintf(devpath, sizeof(devpath), "%s%s", base, name);
486
487    if(!strcmp(uevent->action, "add")) {
488        make_device(devpath, uevent->path, block, uevent->major, uevent->minor);
489        if (links) {
490            for (i = 0; links[i]; i++)
491                make_link(devpath, links[i]);
492        }
493    }
494
495    if(!strcmp(uevent->action, "remove")) {
496        if (links) {
497            for (i = 0; links[i]; i++)
498                remove_link(devpath, links[i]);
499        }
500        unlink(devpath);
501    }
502
503    if (links) {
504        for (i = 0; links[i]; i++)
505            free(links[i]);
506        free(links);
507    }
508}
509
510static int load_firmware(int fw_fd, int loading_fd, int data_fd)
511{
512    struct stat st;
513    long len_to_copy;
514    int ret = 0;
515
516    if(fstat(fw_fd, &st) < 0)
517        return -1;
518    len_to_copy = st.st_size;
519
520    write(loading_fd, "1", 1);  /* start transfer */
521
522    while (len_to_copy > 0) {
523        char buf[PAGE_SIZE];
524        ssize_t nr;
525
526        nr = read(fw_fd, buf, sizeof(buf));
527        if(!nr)
528            break;
529        if(nr < 0) {
530            ret = -1;
531            break;
532        }
533
534        len_to_copy -= nr;
535        while (nr > 0) {
536            ssize_t nw = 0;
537
538            nw = write(data_fd, buf + nw, nr);
539            if(nw <= 0) {
540                ret = -1;
541                goto out;
542            }
543            nr -= nw;
544        }
545    }
546
547out:
548    if(!ret)
549        write(loading_fd, "0", 1);  /* successful end of transfer */
550    else
551        write(loading_fd, "-1", 2); /* abort transfer */
552
553    return ret;
554}
555
556static void process_firmware_event(struct uevent *uevent)
557{
558    char *root, *loading, *data, *file1 = NULL, *file2 = NULL;
559    int l, loading_fd, data_fd, fw_fd;
560
561    log_event_print("firmware event { '%s', '%s' }\n",
562                    uevent->path, uevent->firmware);
563
564    l = asprintf(&root, SYSFS_PREFIX"%s/", uevent->path);
565    if (l == -1)
566        return;
567
568    l = asprintf(&loading, "%sloading", root);
569    if (l == -1)
570        goto root_free_out;
571
572    l = asprintf(&data, "%sdata", root);
573    if (l == -1)
574        goto loading_free_out;
575
576    l = asprintf(&file1, FIRMWARE_DIR1"/%s", uevent->firmware);
577    if (l == -1)
578        goto data_free_out;
579
580    l = asprintf(&file2, FIRMWARE_DIR2"/%s", uevent->firmware);
581    if (l == -1)
582        goto data_free_out;
583
584    loading_fd = open(loading, O_WRONLY);
585    if(loading_fd < 0)
586        goto file_free_out;
587
588    data_fd = open(data, O_WRONLY);
589    if(data_fd < 0)
590        goto loading_close_out;
591
592    fw_fd = open(file1, O_RDONLY);
593    if(fw_fd < 0) {
594        fw_fd = open(file2, O_RDONLY);
595        if (fw_fd < 0) {
596            write(loading_fd, "-1", 2);
597            goto data_close_out;
598        }
599    }
600
601    if(!load_firmware(fw_fd, loading_fd, data_fd))
602        log_event_print("firmware copy success { '%s', '%s' }\n", root, uevent->firmware);
603    else
604        log_event_print("firmware copy failure { '%s', '%s' }\n", root, uevent->firmware);
605
606    close(fw_fd);
607data_close_out:
608    close(data_fd);
609loading_close_out:
610    close(loading_fd);
611file_free_out:
612    free(file1);
613    free(file2);
614data_free_out:
615    free(data);
616loading_free_out:
617    free(loading);
618root_free_out:
619    free(root);
620}
621
622static void handle_firmware_event(struct uevent *uevent)
623{
624    pid_t pid;
625    int status;
626    int ret;
627
628    if(strcmp(uevent->subsystem, "firmware"))
629        return;
630
631    if(strcmp(uevent->action, "add"))
632        return;
633
634    /* we fork, to avoid making large memory allocations in init proper */
635    pid = fork();
636    if (!pid) {
637        process_firmware_event(uevent);
638        exit(EXIT_SUCCESS);
639    } else {
640        do {
641            ret = waitpid(pid, &status, 0);
642        } while (ret == -1 && errno == EINTR);
643    }
644}
645
646#define UEVENT_MSG_LEN  1024
647void handle_device_fd()
648{
649    char msg[UEVENT_MSG_LEN+2];
650    int n;
651    while ((n = uevent_checked_recv(device_fd, msg, UEVENT_MSG_LEN)) > 0) {
652        if(n >= UEVENT_MSG_LEN)   /* overflow -- discard */
653            continue;
654
655        msg[n] = '\0';
656        msg[n+1] = '\0';
657
658        struct uevent uevent;
659        parse_event(msg, &uevent);
660
661        handle_device_event(&uevent);
662        handle_firmware_event(&uevent);
663    }
664}
665
666/* Coldboot walks parts of the /sys tree and pokes the uevent files
667** to cause the kernel to regenerate device add events that happened
668** before init's device manager was started
669**
670** We drain any pending events from the netlink socket every time
671** we poke another uevent file to make sure we don't overrun the
672** socket's buffer.
673*/
674
675static void do_coldboot(DIR *d)
676{
677    struct dirent *de;
678    int dfd, fd;
679
680    dfd = dirfd(d);
681
682    fd = openat(dfd, "uevent", O_WRONLY);
683    if(fd >= 0) {
684        write(fd, "add\n", 4);
685        close(fd);
686        handle_device_fd();
687    }
688
689    while((de = readdir(d))) {
690        DIR *d2;
691
692        if(de->d_type != DT_DIR || de->d_name[0] == '.')
693            continue;
694
695        fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
696        if(fd < 0)
697            continue;
698
699        d2 = fdopendir(fd);
700        if(d2 == 0)
701            close(fd);
702        else {
703            do_coldboot(d2);
704            closedir(d2);
705        }
706    }
707}
708
709static void coldboot(const char *path)
710{
711    DIR *d = opendir(path);
712    if(d) {
713        do_coldboot(d);
714        closedir(d);
715    }
716}
717
718void device_init(void)
719{
720    suseconds_t t0, t1;
721    struct stat info;
722    int fd;
723
724    device_fd = open_uevent_socket();
725    if(device_fd < 0)
726        return;
727
728    fcntl(device_fd, F_SETFD, FD_CLOEXEC);
729    fcntl(device_fd, F_SETFL, O_NONBLOCK);
730
731    if (stat(coldboot_done, &info) < 0) {
732        t0 = get_usecs();
733        coldboot("/sys/class");
734        coldboot("/sys/block");
735        coldboot("/sys/devices");
736        t1 = get_usecs();
737        fd = open(coldboot_done, O_WRONLY|O_CREAT, 0000);
738        close(fd);
739        log_event_print("coldboot %ld uS\n", ((long) (t1 - t0)));
740    } else {
741        log_event_print("skipping coldboot, already done\n");
742    }
743}
744
745int get_device_fd()
746{
747    return device_fd;
748}
749