devices.c revision c0d8fb5842f57bbc244e9c9596707787caabf44e 
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
35#include "devices.h"
36#include "util.h"
37#include "log.h"
38#include "list.h"
39
40#define SYSFS_PREFIX    "/sys"
41#define FIRMWARE_DIR    "/etc/firmware"
42
43static int device_fd = -1;
44
45struct uevent {
46    const char *action;
47    const char *path;
48    const char *subsystem;
49    const char *firmware;
50    const char *partition_name;
51    int partition_num;
52    int major;
53    int minor;
54};
55
56static int open_uevent_socket(void)
57{
58    struct sockaddr_nl addr;
59    int sz = 64*1024; // XXX larger? udev uses 16MB!
60    int s;
61
62    memset(&addr, 0, sizeof(addr));
63    addr.nl_family = AF_NETLINK;
64    addr.nl_pid = getpid();
65    addr.nl_groups = 0xffffffff;
66
67    s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
68    if(s < 0)
69        return -1;
70
71    setsockopt(s, SOL_SOCKET, SO_RCVBUFFORCE, &sz, sizeof(sz));
72
73    if(bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
74        close(s);
75        return -1;
76    }
77
78    return s;
79}
80
81struct perms_ {
82    char *name;
83    mode_t perm;
84    unsigned int uid;
85    unsigned int gid;
86    unsigned short prefix;
87};
88
89struct perm_node {
90    struct perms_ dp;
91    struct listnode plist;
92};
93static list_declare(dev_perms);
94
95/*
96 * Permission override when in emulator mode, must be parsed before
97 * system properties is initalized.
98 */
99int add_dev_perms(const char *name, mode_t perm, unsigned int uid,
100                  unsigned int gid, unsigned short prefix) {
101    int size;
102    char *tmp = 0;
103    struct perm_node *node = malloc(sizeof (struct perm_node));
104    if (!node)
105        return -ENOMEM;
106
107    size = strlen(name) + 1;
108    if ((node->dp.name = malloc(size)) == NULL)
109        return -ENOMEM;
110
111    memcpy(node->dp.name, name, size);
112    node->dp.perm = perm;
113    node->dp.uid = uid;
114    node->dp.gid = gid;
115    node->dp.prefix = prefix;
116
117    list_add_tail(&dev_perms, &node->plist);
118    return 0;
119}
120
121static int get_device_perm_inner(struct perms_ *perms, const char *path,
122                                    unsigned *uid, unsigned *gid, mode_t *perm)
123{
124    int i;
125    for(i = 0; perms[i].name; i++) {
126
127        if(perms[i].prefix) {
128            if(strncmp(path, perms[i].name, strlen(perms[i].name)))
129                continue;
130        } else {
131            if(strcmp(path, perms[i].name))
132                continue;
133        }
134        *uid = perms[i].uid;
135        *gid = perms[i].gid;
136        *perm = perms[i].perm;
137        return 0;
138    }
139    return -1;
140}
141
142/* First checks for emulator specific permissions specified in /proc/cmdline. */
143static mode_t get_device_perm(const char *path, unsigned *uid, unsigned *gid)
144{
145    mode_t perm;
146    struct listnode *node;
147    struct perm_node *perm_node;
148    struct perms_ *dp;
149
150    /* search the perms list in reverse so that ueventd.$hardware can
151     * override ueventd.rc
152     */
153    list_for_each_reverse(node, &dev_perms) {
154        perm_node = node_to_item(node, struct perm_node, plist);
155        dp = &perm_node->dp;
156
157        if (dp->prefix) {
158            if (strncmp(path, dp->name, strlen(dp->name)))
159                continue;
160        } else {
161            if (strcmp(path, dp->name))
162                continue;
163        }
164        *uid = dp->uid;
165        *gid = dp->gid;
166        return dp->perm;
167    }
168    /* Default if nothing found. */
169    *uid = 0;
170    *gid = 0;
171    return 0600;
172}
173
174static void make_device(const char *path, int block, int major, int minor)
175{
176    unsigned uid;
177    unsigned gid;
178    mode_t mode;
179    dev_t dev;
180
181    if(major > 255 || minor > 255)
182        return;
183
184    mode = get_device_perm(path, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
185    dev = (major << 8) | minor;
186    /* Temporarily change egid to avoid race condition setting the gid of the
187     * device node. Unforunately changing the euid would prevent creation of
188     * some device nodes, so the uid has to be set with chown() and is still
189     * racy. Fixing the gid race at least fixed the issue with system_server
190     * opening dynamic input devices under the AID_INPUT gid. */
191    setegid(gid);
192    mknod(path, mode, dev);
193    chown(path, uid, -1);
194    setegid(AID_ROOT);
195}
196
197#if LOG_UEVENTS
198
199static inline suseconds_t get_usecs(void)
200{
201    struct timeval tv;
202    gettimeofday(&tv, 0);
203    return tv.tv_sec * (suseconds_t) 1000000 + tv.tv_usec;
204}
205
206#define log_event_print(x...) INFO(x)
207
208#else
209
210#define log_event_print(fmt, args...)   do { } while (0)
211#define get_usecs()                     0
212
213#endif
214
215static void parse_event(const char *msg, struct uevent *uevent)
216{
217    uevent->action = "";
218    uevent->path = "";
219    uevent->subsystem = "";
220    uevent->firmware = "";
221    uevent->major = -1;
222    uevent->minor = -1;
223    uevent->partition_name = NULL;
224    uevent->partition_num = -1;
225
226        /* currently ignoring SEQNUM */
227    while(*msg) {
228        if(!strncmp(msg, "ACTION=", 7)) {
229            msg += 7;
230            uevent->action = msg;
231        } else if(!strncmp(msg, "DEVPATH=", 8)) {
232            msg += 8;
233            uevent->path = msg;
234        } else if(!strncmp(msg, "SUBSYSTEM=", 10)) {
235            msg += 10;
236            uevent->subsystem = msg;
237        } else if(!strncmp(msg, "FIRMWARE=", 9)) {
238            msg += 9;
239            uevent->firmware = msg;
240        } else if(!strncmp(msg, "MAJOR=", 6)) {
241            msg += 6;
242            uevent->major = atoi(msg);
243        } else if(!strncmp(msg, "MINOR=", 6)) {
244            msg += 6;
245            uevent->minor = atoi(msg);
246        } else if(!strncmp(msg, "PARTN=", 6)) {
247            msg += 6;
248            uevent->partition_num = atoi(msg);
249        } else if(!strncmp(msg, "PARTNAME=", 9)) {
250            msg += 9;
251            uevent->partition_name = msg;
252        }
253
254            /* advance to after the next \0 */
255        while(*msg++)
256            ;
257    }
258
259    log_event_print("event { '%s', '%s', '%s', '%s', %d, %d }\n",
260                    uevent->action, uevent->path, uevent->subsystem,
261                    uevent->firmware, uevent->major, uevent->minor);
262}
263
264static char **parse_platform_block_device(struct uevent *uevent)
265{
266    const char *driver;
267    const char *path;
268    char *slash;
269    int width;
270    char buf[256];
271    char link_path[256];
272    int fd;
273    int link_num = 0;
274    int ret;
275    char *p;
276    unsigned int size;
277    struct stat info;
278
279    char **links = malloc(sizeof(char *) * 4);
280    if (!links)
281        return NULL;
282    memset(links, 0, sizeof(char *) * 4);
283
284    /* Drop "/devices/platform/" */
285    path = uevent->path;
286    driver = path + 18;
287    slash = strchr(driver, '/');
288    if (!slash)
289        goto err;
290    width = slash - driver;
291    if (width <= 0)
292        goto err;
293
294    snprintf(link_path, sizeof(link_path), "/dev/block/platform/%.*s",
295             width, driver);
296
297    if (uevent->partition_name) {
298        p = strdup(uevent->partition_name);
299        sanitize(p);
300        if (asprintf(&links[link_num], "%s/by-name/%s", link_path, p) > 0)
301            link_num++;
302        else
303            links[link_num] = NULL;
304        free(p);
305    }
306
307    if (uevent->partition_num >= 0) {
308        if (asprintf(&links[link_num], "%s/by-num/p%d", link_path, uevent->partition_num) > 0)
309            link_num++;
310        else
311            links[link_num] = NULL;
312    }
313
314    slash = strrchr(path, '/');
315    if (asprintf(&links[link_num], "%s/%s", link_path, slash + 1) > 0)
316        link_num++;
317    else
318        links[link_num] = NULL;
319
320    return links;
321
322err:
323    free(links);
324    return NULL;
325}
326
327static void handle_device_event(struct uevent *uevent)
328{
329    char devpath[96];
330    int devpath_ready = 0;
331    char *base, *name;
332    char **links = NULL;
333    int block;
334    int i;
335
336        /* if it's not a /dev device, nothing to do */
337    if((uevent->major < 0) || (uevent->minor < 0))
338        return;
339
340        /* do we have a name? */
341    name = strrchr(uevent->path, '/');
342    if(!name)
343        return;
344    name++;
345
346        /* too-long names would overrun our buffer */
347    if(strlen(name) > 64)
348        return;
349
350        /* are we block or char? where should we live? */
351    if(!strncmp(uevent->subsystem, "block", 5)) {
352        block = 1;
353        base = "/dev/block/";
354        mkdir(base, 0755);
355        if (!strncmp(uevent->path, "/devices/platform/", 18))
356            links = parse_platform_block_device(uevent);
357    } else {
358        block = 0;
359            /* this should probably be configurable somehow */
360        if (!strncmp(uevent->subsystem, "usb", 3)) {
361            if (!strcmp(uevent->subsystem, "usb")) {
362                /* This imitates the file system that would be created
363                 * if we were using devfs instead.
364                 * Minors are broken up into groups of 128, starting at "001"
365                 */
366                int bus_id = uevent->minor / 128 + 1;
367                int device_id = uevent->minor % 128 + 1;
368                /* build directories */
369                mkdir("/dev/bus", 0755);
370                mkdir("/dev/bus/usb", 0755);
371                snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d", bus_id);
372                mkdir(devpath, 0755);
373                snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d/%03d", bus_id, device_id);
374                devpath_ready = 1;
375            } else {
376                /* ignore other USB events */
377                return;
378            }
379        } else if (!strncmp(uevent->subsystem, "graphics", 8)) {
380            base = "/dev/graphics/";
381            mkdir(base, 0755);
382        } else if (!strncmp(uevent->subsystem, "oncrpc", 6)) {
383            base = "/dev/oncrpc/";
384            mkdir(base, 0755);
385        } else if (!strncmp(uevent->subsystem, "adsp", 4)) {
386            base = "/dev/adsp/";
387            mkdir(base, 0755);
388        } else if (!strncmp(uevent->subsystem, "msm_camera", 10)) {
389            base = "/dev/msm_camera/";
390            mkdir(base, 0755);
391        } else if(!strncmp(uevent->subsystem, "input", 5)) {
392            base = "/dev/input/";
393            mkdir(base, 0755);
394        } else if(!strncmp(uevent->subsystem, "mtd", 3)) {
395            base = "/dev/mtd/";
396            mkdir(base, 0755);
397        } else if(!strncmp(uevent->subsystem, "sound", 5)) {
398            base = "/dev/snd/";
399            mkdir(base, 0755);
400        } else if(!strncmp(uevent->subsystem, "misc", 4) &&
401                    !strncmp(name, "log_", 4)) {
402            base = "/dev/log/";
403            mkdir(base, 0755);
404            name += 4;
405        } else
406            base = "/dev/";
407    }
408
409    if (!devpath_ready)
410        snprintf(devpath, sizeof(devpath), "%s%s", base, name);
411
412    if(!strcmp(uevent->action, "add")) {
413        make_device(devpath, block, uevent->major, uevent->minor);
414        if (links) {
415            for (i = 0; links[i]; i++)
416                make_link(devpath, links[i]);
417        }
418    }
419
420    if(!strcmp(uevent->action, "remove")) {
421        if (links) {
422            for (i = 0; links[i]; i++)
423                remove_link(devpath, links[i]);
424        }
425        unlink(devpath);
426    }
427
428    if (links) {
429        for (i = 0; links[i]; i++)
430            free(links[i]);
431        free(links);
432    }
433}
434
435static int load_firmware(int fw_fd, int loading_fd, int data_fd)
436{
437    struct stat st;
438    long len_to_copy;
439    int ret = 0;
440
441    if(fstat(fw_fd, &st) < 0)
442        return -1;
443    len_to_copy = st.st_size;
444
445    write(loading_fd, "1", 1);  /* start transfer */
446
447    while (len_to_copy > 0) {
448        char buf[PAGE_SIZE];
449        ssize_t nr;
450
451        nr = read(fw_fd, buf, sizeof(buf));
452        if(!nr)
453            break;
454        if(nr < 0) {
455            ret = -1;
456            break;
457        }
458
459        len_to_copy -= nr;
460        while (nr > 0) {
461            ssize_t nw = 0;
462
463            nw = write(data_fd, buf + nw, nr);
464            if(nw <= 0) {
465                ret = -1;
466                goto out;
467            }
468            nr -= nw;
469        }
470    }
471
472out:
473    if(!ret)
474        write(loading_fd, "0", 1);  /* successful end of transfer */
475    else
476        write(loading_fd, "-1", 2); /* abort transfer */
477
478    return ret;
479}
480
481static void process_firmware_event(struct uevent *uevent)
482{
483    char *root, *loading, *data, *file;
484    int l, loading_fd, data_fd, fw_fd;
485
486    log_event_print("firmware event { '%s', '%s' }\n",
487                    uevent->path, uevent->firmware);
488
489    l = asprintf(&root, SYSFS_PREFIX"%s/", uevent->path);
490    if (l == -1)
491        return;
492
493    l = asprintf(&loading, "%sloading", root);
494    if (l == -1)
495        goto root_free_out;
496
497    l = asprintf(&data, "%sdata", root);
498    if (l == -1)
499        goto loading_free_out;
500
501    l = asprintf(&file, FIRMWARE_DIR"/%s", uevent->firmware);
502    if (l == -1)
503        goto data_free_out;
504
505    loading_fd = open(loading, O_WRONLY);
506    if(loading_fd < 0)
507        goto file_free_out;
508
509    data_fd = open(data, O_WRONLY);
510    if(data_fd < 0)
511        goto loading_close_out;
512
513    fw_fd = open(file, O_RDONLY);
514    if(fw_fd < 0)
515        goto data_close_out;
516
517    if(!load_firmware(fw_fd, loading_fd, data_fd))
518        log_event_print("firmware copy success { '%s', '%s' }\n", root, file);
519    else
520        log_event_print("firmware copy failure { '%s', '%s' }\n", root, file);
521
522    close(fw_fd);
523data_close_out:
524    close(data_fd);
525loading_close_out:
526    close(loading_fd);
527file_free_out:
528    free(file);
529data_free_out:
530    free(data);
531loading_free_out:
532    free(loading);
533root_free_out:
534    free(root);
535}
536
537static void handle_firmware_event(struct uevent *uevent)
538{
539    pid_t pid;
540
541    if(strcmp(uevent->subsystem, "firmware"))
542        return;
543
544    if(strcmp(uevent->action, "add"))
545        return;
546
547    /* we fork, to avoid making large memory allocations in init proper */
548    pid = fork();
549    if (!pid) {
550        process_firmware_event(uevent);
551        exit(EXIT_SUCCESS);
552    }
553}
554
555#define UEVENT_MSG_LEN  1024
556void handle_device_fd()
557{
558    char msg[UEVENT_MSG_LEN+2];
559    int n;
560
561    while((n = recv(device_fd, msg, UEVENT_MSG_LEN, 0)) > 0) {
562        struct uevent uevent;
563
564        if(n == UEVENT_MSG_LEN)   /* overflow -- discard */
565            continue;
566
567        msg[n] = '\0';
568        msg[n+1] = '\0';
569
570        parse_event(msg, &uevent);
571
572        handle_device_event(&uevent);
573        handle_firmware_event(&uevent);
574    }
575}
576
577/* Coldboot walks parts of the /sys tree and pokes the uevent files
578** to cause the kernel to regenerate device add events that happened
579** before init's device manager was started
580**
581** We drain any pending events from the netlink socket every time
582** we poke another uevent file to make sure we don't overrun the
583** socket's buffer.
584*/
585
586static void do_coldboot(DIR *d)
587{
588    struct dirent *de;
589    int dfd, fd;
590
591    dfd = dirfd(d);
592
593    fd = openat(dfd, "uevent", O_WRONLY);
594    if(fd >= 0) {
595        write(fd, "add\n", 4);
596        close(fd);
597        handle_device_fd();
598    }
599
600    while((de = readdir(d))) {
601        DIR *d2;
602
603        if(de->d_type != DT_DIR || de->d_name[0] == '.')
604            continue;
605
606        fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
607        if(fd < 0)
608            continue;
609
610        d2 = fdopendir(fd);
611        if(d2 == 0)
612            close(fd);
613        else {
614            do_coldboot(d2);
615            closedir(d2);
616        }
617    }
618}
619
620static void coldboot(const char *path)
621{
622    DIR *d = opendir(path);
623    if(d) {
624        do_coldboot(d);
625        closedir(d);
626    }
627}
628
629void device_init(void)
630{
631    suseconds_t t0, t1;
632    struct stat info;
633    int fd;
634
635    device_fd = open_uevent_socket();
636    if(device_fd < 0)
637        return;
638
639    fcntl(device_fd, F_SETFD, FD_CLOEXEC);
640    fcntl(device_fd, F_SETFL, O_NONBLOCK);
641
642    if (stat(coldboot_done, &info) < 0) {
643        t0 = get_usecs();
644        coldboot("/sys/class");
645        coldboot("/sys/block");
646        coldboot("/sys/devices");
647        t1 = get_usecs();
648        fd = open(coldboot_done, O_WRONLY|O_CREAT, 0000);
649        close(fd);
650        log_event_print("coldboot %ld uS\n", ((long) (t1 - t0)));
651    } else {
652        log_event_print("skipping coldboot, already done\n");
653    }
654}
655
656int get_device_fd()
657{
658    return device_fd;
659}
660