devices.c revision 982a815c10cc28707d81c46112fc45b1c10df3be 
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_DIR    "/etc/firmware"
43
44static int device_fd = -1;
45
46struct uevent {
47    const char *action;
48    const char *path;
49    const char *subsystem;
50    const char *firmware;
51    const char *partition_name;
52    int partition_num;
53    int major;
54    int minor;
55};
56
57static int open_uevent_socket(void)
58{
59    struct sockaddr_nl addr;
60    int sz = 64*1024; // XXX larger? udev uses 16MB!
61    int s;
62
63    memset(&addr, 0, sizeof(addr));
64    addr.nl_family = AF_NETLINK;
65    addr.nl_pid = getpid();
66    addr.nl_groups = 0xffffffff;
67
68    s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
69    if(s < 0)
70        return -1;
71
72    setsockopt(s, SOL_SOCKET, SO_RCVBUFFORCE, &sz, sizeof(sz));
73
74    if(bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
75        close(s);
76        return -1;
77    }
78
79    return s;
80}
81
82struct perms_ {
83    char *name;
84    mode_t perm;
85    unsigned int uid;
86    unsigned int gid;
87    unsigned short prefix;
88};
89
90struct perm_node {
91    struct perms_ dp;
92    struct listnode plist;
93};
94static list_declare(dev_perms);
95
96/*
97 * Permission override when in emulator mode, must be parsed before
98 * system properties is initalized.
99 */
100int add_dev_perms(const char *name, mode_t perm, unsigned int uid,
101                  unsigned int gid, unsigned short prefix) {
102    int size;
103    char *tmp = 0;
104    struct perm_node *node = malloc(sizeof (struct perm_node));
105    if (!node)
106        return -ENOMEM;
107
108    size = strlen(name) + 1;
109    if ((node->dp.name = malloc(size)) == NULL)
110        return -ENOMEM;
111
112    memcpy(node->dp.name, name, size);
113    node->dp.perm = perm;
114    node->dp.uid = uid;
115    node->dp.gid = gid;
116    node->dp.prefix = prefix;
117
118    list_add_tail(&dev_perms, &node->plist);
119    return 0;
120}
121
122static int get_device_perm_inner(struct perms_ *perms, const char *path,
123                                    unsigned *uid, unsigned *gid, mode_t *perm)
124{
125    int i;
126    for(i = 0; perms[i].name; i++) {
127
128        if(perms[i].prefix) {
129            if(strncmp(path, perms[i].name, strlen(perms[i].name)))
130                continue;
131        } else {
132            if(strcmp(path, perms[i].name))
133                continue;
134        }
135        *uid = perms[i].uid;
136        *gid = perms[i].gid;
137        *perm = perms[i].perm;
138        return 0;
139    }
140    return -1;
141}
142
143/* First checks for emulator specific permissions specified in /proc/cmdline. */
144static mode_t get_device_perm(const char *path, unsigned *uid, unsigned *gid)
145{
146    mode_t perm;
147    struct listnode *node;
148    struct perm_node *perm_node;
149    struct perms_ *dp;
150
151    /* search the perms list in reverse so that ueventd.$hardware can
152     * override ueventd.rc
153     */
154    list_for_each_reverse(node, &dev_perms) {
155        perm_node = node_to_item(node, struct perm_node, plist);
156        dp = &perm_node->dp;
157
158        if (dp->prefix) {
159            if (strncmp(path, dp->name, strlen(dp->name)))
160                continue;
161        } else {
162            if (strcmp(path, dp->name))
163                continue;
164        }
165        *uid = dp->uid;
166        *gid = dp->gid;
167        return dp->perm;
168    }
169    /* Default if nothing found. */
170    *uid = 0;
171    *gid = 0;
172    return 0600;
173}
174
175static void make_device(const char *path, int block, int major, int minor)
176{
177    unsigned uid;
178    unsigned gid;
179    mode_t mode;
180    dev_t dev;
181
182    if(major > 255 || minor > 255)
183        return;
184
185    mode = get_device_perm(path, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
186    dev = (major << 8) | minor;
187    /* Temporarily change egid to avoid race condition setting the gid of the
188     * device node. Unforunately changing the euid would prevent creation of
189     * some device nodes, so the uid has to be set with chown() and is still
190     * racy. Fixing the gid race at least fixed the issue with system_server
191     * opening dynamic input devices under the AID_INPUT gid. */
192    setegid(gid);
193    mknod(path, mode, dev);
194    chown(path, uid, -1);
195    setegid(AID_ROOT);
196}
197
198#if LOG_UEVENTS
199
200static inline suseconds_t get_usecs(void)
201{
202    struct timeval tv;
203    gettimeofday(&tv, 0);
204    return tv.tv_sec * (suseconds_t) 1000000 + tv.tv_usec;
205}
206
207#define log_event_print(x...) INFO(x)
208
209#else
210
211#define log_event_print(fmt, args...)   do { } while (0)
212#define get_usecs()                     0
213
214#endif
215
216static void parse_event(const char *msg, struct uevent *uevent)
217{
218    uevent->action = "";
219    uevent->path = "";
220    uevent->subsystem = "";
221    uevent->firmware = "";
222    uevent->major = -1;
223    uevent->minor = -1;
224    uevent->partition_name = NULL;
225    uevent->partition_num = -1;
226
227        /* currently ignoring SEQNUM */
228    while(*msg) {
229        if(!strncmp(msg, "ACTION=", 7)) {
230            msg += 7;
231            uevent->action = msg;
232        } else if(!strncmp(msg, "DEVPATH=", 8)) {
233            msg += 8;
234            uevent->path = msg;
235        } else if(!strncmp(msg, "SUBSYSTEM=", 10)) {
236            msg += 10;
237            uevent->subsystem = msg;
238        } else if(!strncmp(msg, "FIRMWARE=", 9)) {
239            msg += 9;
240            uevent->firmware = msg;
241        } else if(!strncmp(msg, "MAJOR=", 6)) {
242            msg += 6;
243            uevent->major = atoi(msg);
244        } else if(!strncmp(msg, "MINOR=", 6)) {
245            msg += 6;
246            uevent->minor = atoi(msg);
247        } else if(!strncmp(msg, "PARTN=", 6)) {
248            msg += 6;
249            uevent->partition_num = atoi(msg);
250        } else if(!strncmp(msg, "PARTNAME=", 9)) {
251            msg += 9;
252            uevent->partition_name = msg;
253        }
254
255            /* advance to after the next \0 */
256        while(*msg++)
257            ;
258    }
259
260    log_event_print("event { '%s', '%s', '%s', '%s', %d, %d }\n",
261                    uevent->action, uevent->path, uevent->subsystem,
262                    uevent->firmware, uevent->major, uevent->minor);
263}
264
265static char **parse_platform_block_device(struct uevent *uevent)
266{
267    const char *driver;
268    const char *path;
269    char *slash;
270    int width;
271    char buf[256];
272    char link_path[256];
273    int fd;
274    int link_num = 0;
275    int ret;
276    char *p;
277    unsigned int size;
278    struct stat info;
279
280    char **links = malloc(sizeof(char *) * 4);
281    if (!links)
282        return NULL;
283    memset(links, 0, sizeof(char *) * 4);
284
285    /* Drop "/devices/platform/" */
286    path = uevent->path;
287    driver = path + 18;
288    slash = strchr(driver, '/');
289    if (!slash)
290        goto err;
291    width = slash - driver;
292    if (width <= 0)
293        goto err;
294
295    snprintf(link_path, sizeof(link_path), "/dev/block/platform/%.*s",
296             width, driver);
297
298    if (uevent->partition_name) {
299        p = strdup(uevent->partition_name);
300        sanitize(p);
301        if (asprintf(&links[link_num], "%s/by-name/%s", link_path, p) > 0)
302            link_num++;
303        else
304            links[link_num] = NULL;
305        free(p);
306    }
307
308    if (uevent->partition_num >= 0) {
309        if (asprintf(&links[link_num], "%s/by-num/p%d", link_path, uevent->partition_num) > 0)
310            link_num++;
311        else
312            links[link_num] = NULL;
313    }
314
315    slash = strrchr(path, '/');
316    if (asprintf(&links[link_num], "%s/%s", link_path, slash + 1) > 0)
317        link_num++;
318    else
319        links[link_num] = NULL;
320
321    return links;
322
323err:
324    free(links);
325    return NULL;
326}
327
328static void handle_device_event(struct uevent *uevent)
329{
330    char devpath[96];
331    int devpath_ready = 0;
332    char *base, *name;
333    char **links = NULL;
334    int block;
335    int i;
336
337        /* if it's not a /dev device, nothing to do */
338    if((uevent->major < 0) || (uevent->minor < 0))
339        return;
340
341        /* do we have a name? */
342    name = strrchr(uevent->path, '/');
343    if(!name)
344        return;
345    name++;
346
347        /* too-long names would overrun our buffer */
348    if(strlen(name) > 64)
349        return;
350
351        /* are we block or char? where should we live? */
352    if(!strncmp(uevent->subsystem, "block", 5)) {
353        block = 1;
354        base = "/dev/block/";
355        mkdir(base, 0755);
356        if (!strncmp(uevent->path, "/devices/platform/", 18))
357            links = parse_platform_block_device(uevent);
358    } else {
359        block = 0;
360            /* this should probably be configurable somehow */
361        if (!strncmp(uevent->subsystem, "usb", 3)) {
362            if (!strcmp(uevent->subsystem, "usb")) {
363                /* This imitates the file system that would be created
364                 * if we were using devfs instead.
365                 * Minors are broken up into groups of 128, starting at "001"
366                 */
367                int bus_id = uevent->minor / 128 + 1;
368                int device_id = uevent->minor % 128 + 1;
369                /* build directories */
370                mkdir("/dev/bus", 0755);
371                mkdir("/dev/bus/usb", 0755);
372                snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d", bus_id);
373                mkdir(devpath, 0755);
374                snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d/%03d", bus_id, device_id);
375                devpath_ready = 1;
376            } else {
377                /* ignore other USB events */
378                return;
379            }
380        } else if (!strncmp(uevent->subsystem, "graphics", 8)) {
381            base = "/dev/graphics/";
382            mkdir(base, 0755);
383        } else if (!strncmp(uevent->subsystem, "oncrpc", 6)) {
384            base = "/dev/oncrpc/";
385            mkdir(base, 0755);
386        } else if (!strncmp(uevent->subsystem, "adsp", 4)) {
387            base = "/dev/adsp/";
388            mkdir(base, 0755);
389        } else if (!strncmp(uevent->subsystem, "msm_camera", 10)) {
390            base = "/dev/msm_camera/";
391            mkdir(base, 0755);
392        } else if(!strncmp(uevent->subsystem, "input", 5)) {
393            base = "/dev/input/";
394            mkdir(base, 0755);
395        } else if(!strncmp(uevent->subsystem, "mtd", 3)) {
396            base = "/dev/mtd/";
397            mkdir(base, 0755);
398        } else if(!strncmp(uevent->subsystem, "sound", 5)) {
399            base = "/dev/snd/";
400            mkdir(base, 0755);
401        } else if(!strncmp(uevent->subsystem, "misc", 4) &&
402                    !strncmp(name, "log_", 4)) {
403            base = "/dev/log/";
404            mkdir(base, 0755);
405            name += 4;
406        } else
407            base = "/dev/";
408    }
409
410    if (!devpath_ready)
411        snprintf(devpath, sizeof(devpath), "%s%s", base, name);
412
413    if(!strcmp(uevent->action, "add")) {
414        make_device(devpath, block, uevent->major, uevent->minor);
415        if (links) {
416            for (i = 0; links[i]; i++)
417                make_link(devpath, links[i]);
418        }
419    }
420
421    if(!strcmp(uevent->action, "remove")) {
422        if (links) {
423            for (i = 0; links[i]; i++)
424                remove_link(devpath, links[i]);
425        }
426        unlink(devpath);
427    }
428
429    if (links) {
430        for (i = 0; links[i]; i++)
431            free(links[i]);
432        free(links);
433    }
434}
435
436static int load_firmware(int fw_fd, int loading_fd, int data_fd)
437{
438    struct stat st;
439    long len_to_copy;
440    int ret = 0;
441
442    if(fstat(fw_fd, &st) < 0)
443        return -1;
444    len_to_copy = st.st_size;
445
446    write(loading_fd, "1", 1);  /* start transfer */
447
448    while (len_to_copy > 0) {
449        char buf[PAGE_SIZE];
450        ssize_t nr;
451
452        nr = read(fw_fd, buf, sizeof(buf));
453        if(!nr)
454            break;
455        if(nr < 0) {
456            ret = -1;
457            break;
458        }
459
460        len_to_copy -= nr;
461        while (nr > 0) {
462            ssize_t nw = 0;
463
464            nw = write(data_fd, buf + nw, nr);
465            if(nw <= 0) {
466                ret = -1;
467                goto out;
468            }
469            nr -= nw;
470        }
471    }
472
473out:
474    if(!ret)
475        write(loading_fd, "0", 1);  /* successful end of transfer */
476    else
477        write(loading_fd, "-1", 2); /* abort transfer */
478
479    return ret;
480}
481
482static void process_firmware_event(struct uevent *uevent)
483{
484    char *root, *loading, *data, *file;
485    int l, loading_fd, data_fd, fw_fd;
486
487    log_event_print("firmware event { '%s', '%s' }\n",
488                    uevent->path, uevent->firmware);
489
490    l = asprintf(&root, SYSFS_PREFIX"%s/", uevent->path);
491    if (l == -1)
492        return;
493
494    l = asprintf(&loading, "%sloading", root);
495    if (l == -1)
496        goto root_free_out;
497
498    l = asprintf(&data, "%sdata", root);
499    if (l == -1)
500        goto loading_free_out;
501
502    l = asprintf(&file, FIRMWARE_DIR"/%s", uevent->firmware);
503    if (l == -1)
504        goto data_free_out;
505
506    loading_fd = open(loading, O_WRONLY);
507    if(loading_fd < 0)
508        goto file_free_out;
509
510    data_fd = open(data, O_WRONLY);
511    if(data_fd < 0)
512        goto loading_close_out;
513
514    fw_fd = open(file, O_RDONLY);
515    if(fw_fd < 0)
516        goto data_close_out;
517
518    if(!load_firmware(fw_fd, loading_fd, data_fd))
519        log_event_print("firmware copy success { '%s', '%s' }\n", root, file);
520    else
521        log_event_print("firmware copy failure { '%s', '%s' }\n", root, file);
522
523    close(fw_fd);
524data_close_out:
525    close(data_fd);
526loading_close_out:
527    close(loading_fd);
528file_free_out:
529    free(file);
530data_free_out:
531    free(data);
532loading_free_out:
533    free(loading);
534root_free_out:
535    free(root);
536}
537
538static void handle_firmware_event(struct uevent *uevent)
539{
540    pid_t pid;
541    int status;
542    int ret;
543
544    if(strcmp(uevent->subsystem, "firmware"))
545        return;
546
547    if(strcmp(uevent->action, "add"))
548        return;
549
550    /* we fork, to avoid making large memory allocations in init proper */
551    pid = fork();
552    if (!pid) {
553        process_firmware_event(uevent);
554        exit(EXIT_SUCCESS);
555    } else {
556        do {
557            ret = waitpid(pid, &status, 0);
558        } while (ret == -1 && errno == EINTR);
559    }
560}
561
562#define UEVENT_MSG_LEN  1024
563void handle_device_fd()
564{
565    char msg[UEVENT_MSG_LEN+2];
566    int n;
567
568    while((n = recv(device_fd, msg, UEVENT_MSG_LEN, 0)) > 0) {
569        struct uevent uevent;
570
571        if(n == UEVENT_MSG_LEN)   /* overflow -- discard */
572            continue;
573
574        msg[n] = '\0';
575        msg[n+1] = '\0';
576
577        parse_event(msg, &uevent);
578
579        handle_device_event(&uevent);
580        handle_firmware_event(&uevent);
581    }
582}
583
584/* Coldboot walks parts of the /sys tree and pokes the uevent files
585** to cause the kernel to regenerate device add events that happened
586** before init's device manager was started
587**
588** We drain any pending events from the netlink socket every time
589** we poke another uevent file to make sure we don't overrun the
590** socket's buffer.
591*/
592
593static void do_coldboot(DIR *d)
594{
595    struct dirent *de;
596    int dfd, fd;
597
598    dfd = dirfd(d);
599
600    fd = openat(dfd, "uevent", O_WRONLY);
601    if(fd >= 0) {
602        write(fd, "add\n", 4);
603        close(fd);
604        handle_device_fd();
605    }
606
607    while((de = readdir(d))) {
608        DIR *d2;
609
610        if(de->d_type != DT_DIR || de->d_name[0] == '.')
611            continue;
612
613        fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
614        if(fd < 0)
615            continue;
616
617        d2 = fdopendir(fd);
618        if(d2 == 0)
619            close(fd);
620        else {
621            do_coldboot(d2);
622            closedir(d2);
623        }
624    }
625}
626
627static void coldboot(const char *path)
628{
629    DIR *d = opendir(path);
630    if(d) {
631        do_coldboot(d);
632        closedir(d);
633    }
634}
635
636void device_init(void)
637{
638    suseconds_t t0, t1;
639    struct stat info;
640    int fd;
641
642    device_fd = open_uevent_socket();
643    if(device_fd < 0)
644        return;
645
646    fcntl(device_fd, F_SETFD, FD_CLOEXEC);
647    fcntl(device_fd, F_SETFL, O_NONBLOCK);
648
649    if (stat(coldboot_done, &info) < 0) {
650        t0 = get_usecs();
651        coldboot("/sys/class");
652        coldboot("/sys/block");
653        coldboot("/sys/devices");
654        t1 = get_usecs();
655        fd = open(coldboot_done, O_WRONLY|O_CREAT, 0000);
656        close(fd);
657        log_event_print("coldboot %ld uS\n", ((long) (t1 - t0)));
658    } else {
659        log_event_print("skipping coldboot, already done\n");
660    }
661}
662
663int get_device_fd()
664{
665    return device_fd;
666}
667