devices.c revision 44b65d047cc39baf30e21bfd8dd438f6bc1f77f5 
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    char *base, *name;
331    char **links = NULL;
332    int block;
333    int i;
334
335        /* if it's not a /dev device, nothing to do */
336    if((uevent->major < 0) || (uevent->minor < 0))
337        return;
338
339        /* do we have a name? */
340    name = strrchr(uevent->path, '/');
341    if(!name)
342        return;
343    name++;
344
345        /* too-long names would overrun our buffer */
346    if(strlen(name) > 64)
347        return;
348
349        /* are we block or char? where should we live? */
350    if(!strncmp(uevent->subsystem, "block", 5)) {
351        block = 1;
352        base = "/dev/block/";
353        mkdir(base, 0755);
354        if (!strncmp(uevent->path, "/devices/platform/", 18))
355            links = parse_platform_block_device(uevent);
356    } else {
357        block = 0;
358            /* this should probably be configurable somehow */
359        if(!strncmp(uevent->subsystem, "graphics", 8)) {
360            base = "/dev/graphics/";
361            mkdir(base, 0755);
362        } else if (!strncmp(uevent->subsystem, "oncrpc", 6)) {
363            base = "/dev/oncrpc/";
364            mkdir(base, 0755);
365        } else if (!strncmp(uevent->subsystem, "adsp", 4)) {
366            base = "/dev/adsp/";
367            mkdir(base, 0755);
368        } else if (!strncmp(uevent->subsystem, "msm_camera", 10)) {
369            base = "/dev/msm_camera/";
370            mkdir(base, 0755);
371        } else if(!strncmp(uevent->subsystem, "input", 5)) {
372            base = "/dev/input/";
373            mkdir(base, 0755);
374        } else if(!strncmp(uevent->subsystem, "mtd", 3)) {
375            base = "/dev/mtd/";
376            mkdir(base, 0755);
377        } else if(!strncmp(uevent->subsystem, "sound", 5)) {
378            base = "/dev/snd/";
379            mkdir(base, 0755);
380        } else if(!strncmp(uevent->subsystem, "misc", 4) &&
381                    !strncmp(name, "log_", 4)) {
382            base = "/dev/log/";
383            mkdir(base, 0755);
384            name += 4;
385        } else
386            base = "/dev/";
387    }
388
389    snprintf(devpath, sizeof(devpath), "%s%s", base, name);
390
391    if(!strcmp(uevent->action, "add")) {
392        make_device(devpath, block, uevent->major, uevent->minor);
393        if (links) {
394            for (i = 0; links[i]; i++)
395                make_link(devpath, links[i]);
396        }
397    }
398
399    if(!strcmp(uevent->action, "remove")) {
400        if (links) {
401            for (i = 0; links[i]; i++)
402                remove_link(devpath, links[i]);
403        }
404        unlink(devpath);
405    }
406
407    if (links) {
408        for (i = 0; links[i]; i++)
409            free(links[i]);
410        free(links);
411    }
412}
413
414static int load_firmware(int fw_fd, int loading_fd, int data_fd)
415{
416    struct stat st;
417    long len_to_copy;
418    int ret = 0;
419
420    if(fstat(fw_fd, &st) < 0)
421        return -1;
422    len_to_copy = st.st_size;
423
424    write(loading_fd, "1", 1);  /* start transfer */
425
426    while (len_to_copy > 0) {
427        char buf[PAGE_SIZE];
428        ssize_t nr;
429
430        nr = read(fw_fd, buf, sizeof(buf));
431        if(!nr)
432            break;
433        if(nr < 0) {
434            ret = -1;
435            break;
436        }
437
438        len_to_copy -= nr;
439        while (nr > 0) {
440            ssize_t nw = 0;
441
442            nw = write(data_fd, buf + nw, nr);
443            if(nw <= 0) {
444                ret = -1;
445                goto out;
446            }
447            nr -= nw;
448        }
449    }
450
451out:
452    if(!ret)
453        write(loading_fd, "0", 1);  /* successful end of transfer */
454    else
455        write(loading_fd, "-1", 2); /* abort transfer */
456
457    return ret;
458}
459
460static void process_firmware_event(struct uevent *uevent)
461{
462    char *root, *loading, *data, *file;
463    int l, loading_fd, data_fd, fw_fd;
464
465    log_event_print("firmware event { '%s', '%s' }\n",
466                    uevent->path, uevent->firmware);
467
468    l = asprintf(&root, SYSFS_PREFIX"%s/", uevent->path);
469    if (l == -1)
470        return;
471
472    l = asprintf(&loading, "%sloading", root);
473    if (l == -1)
474        goto root_free_out;
475
476    l = asprintf(&data, "%sdata", root);
477    if (l == -1)
478        goto loading_free_out;
479
480    l = asprintf(&file, FIRMWARE_DIR"/%s", uevent->firmware);
481    if (l == -1)
482        goto data_free_out;
483
484    loading_fd = open(loading, O_WRONLY);
485    if(loading_fd < 0)
486        goto file_free_out;
487
488    data_fd = open(data, O_WRONLY);
489    if(data_fd < 0)
490        goto loading_close_out;
491
492    fw_fd = open(file, O_RDONLY);
493    if(fw_fd < 0)
494        goto data_close_out;
495
496    if(!load_firmware(fw_fd, loading_fd, data_fd))
497        log_event_print("firmware copy success { '%s', '%s' }\n", root, file);
498    else
499        log_event_print("firmware copy failure { '%s', '%s' }\n", root, file);
500
501    close(fw_fd);
502data_close_out:
503    close(data_fd);
504loading_close_out:
505    close(loading_fd);
506file_free_out:
507    free(file);
508data_free_out:
509    free(data);
510loading_free_out:
511    free(loading);
512root_free_out:
513    free(root);
514}
515
516static void handle_firmware_event(struct uevent *uevent)
517{
518    pid_t pid;
519
520    if(strcmp(uevent->subsystem, "firmware"))
521        return;
522
523    if(strcmp(uevent->action, "add"))
524        return;
525
526    /* we fork, to avoid making large memory allocations in init proper */
527    pid = fork();
528    if (!pid) {
529        process_firmware_event(uevent);
530        exit(EXIT_SUCCESS);
531    }
532}
533
534#define UEVENT_MSG_LEN  1024
535void handle_device_fd()
536{
537    char msg[UEVENT_MSG_LEN+2];
538    int n;
539
540    while((n = recv(device_fd, msg, UEVENT_MSG_LEN, 0)) > 0) {
541        struct uevent uevent;
542
543        if(n == UEVENT_MSG_LEN)   /* overflow -- discard */
544            continue;
545
546        msg[n] = '\0';
547        msg[n+1] = '\0';
548
549        parse_event(msg, &uevent);
550
551        handle_device_event(&uevent);
552        handle_firmware_event(&uevent);
553    }
554}
555
556/* Coldboot walks parts of the /sys tree and pokes the uevent files
557** to cause the kernel to regenerate device add events that happened
558** before init's device manager was started
559**
560** We drain any pending events from the netlink socket every time
561** we poke another uevent file to make sure we don't overrun the
562** socket's buffer.
563*/
564
565static void do_coldboot(DIR *d)
566{
567    struct dirent *de;
568    int dfd, fd;
569
570    dfd = dirfd(d);
571
572    fd = openat(dfd, "uevent", O_WRONLY);
573    if(fd >= 0) {
574        write(fd, "add\n", 4);
575        close(fd);
576        handle_device_fd();
577    }
578
579    while((de = readdir(d))) {
580        DIR *d2;
581
582        if(de->d_type != DT_DIR || de->d_name[0] == '.')
583            continue;
584
585        fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
586        if(fd < 0)
587            continue;
588
589        d2 = fdopendir(fd);
590        if(d2 == 0)
591            close(fd);
592        else {
593            do_coldboot(d2);
594            closedir(d2);
595        }
596    }
597}
598
599static void coldboot(const char *path)
600{
601    DIR *d = opendir(path);
602    if(d) {
603        do_coldboot(d);
604        closedir(d);
605    }
606}
607
608void device_init(void)
609{
610    suseconds_t t0, t1;
611    struct stat info;
612    int fd;
613
614    device_fd = open_uevent_socket();
615    if(device_fd < 0)
616        return;
617
618    fcntl(device_fd, F_SETFD, FD_CLOEXEC);
619    fcntl(device_fd, F_SETFL, O_NONBLOCK);
620
621    if (stat(coldboot_done, &info) < 0) {
622        t0 = get_usecs();
623        coldboot("/sys/class");
624        coldboot("/sys/block");
625        coldboot("/sys/devices");
626        t1 = get_usecs();
627        fd = open(coldboot_done, O_WRONLY|O_CREAT, 0000);
628        close(fd);
629        log_event_print("coldboot %ld uS\n", ((long) (t1 - t0)));
630    } else {
631        log_event_print("skipping coldboot, already done\n");
632    }
633}
634
635int get_device_fd()
636{
637    return device_fd;
638}
639