devices.c revision 02863b957cfbfc302d3136ed78c0cba86accacd8 
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_DIR1   "/etc/firmware"
43#define FIRMWARE_DIR2   "/vendor/firmware"
44
45static int device_fd = -1;
46
47struct uevent {
48    const char *action;
49    const char *path;
50    const char *subsystem;
51    const char *firmware;
52    const char *partition_name;
53    int partition_num;
54    int major;
55    int minor;
56};
57
58static int open_uevent_socket(void)
59{
60    struct sockaddr_nl addr;
61    int sz = 64*1024; // XXX larger? udev uses 16MB!
62    int on = 1;
63    int s;
64
65    memset(&addr, 0, sizeof(addr));
66    addr.nl_family = AF_NETLINK;
67    addr.nl_pid = getpid();
68    addr.nl_groups = 0xffffffff;
69
70    s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
71    if(s < 0)
72        return -1;
73
74    setsockopt(s, SOL_SOCKET, SO_RCVBUFFORCE, &sz, sizeof(sz));
75    setsockopt(s, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
76
77    if(bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
78        close(s);
79        return -1;
80    }
81
82    return s;
83}
84
85struct perms_ {
86    char *name;
87    mode_t perm;
88    unsigned int uid;
89    unsigned int gid;
90    unsigned short prefix;
91};
92
93struct perm_node {
94    struct perms_ dp;
95    struct listnode plist;
96};
97static list_declare(dev_perms);
98
99/*
100 * Permission override when in emulator mode, must be parsed before
101 * system properties is initalized.
102 */
103int add_dev_perms(const char *name, mode_t perm, unsigned int uid,
104                  unsigned int gid, unsigned short prefix) {
105    int size;
106    char *tmp = 0;
107    struct perm_node *node = malloc(sizeof (struct perm_node));
108    if (!node)
109        return -ENOMEM;
110
111    size = strlen(name) + 1;
112    if ((node->dp.name = malloc(size)) == NULL)
113        return -ENOMEM;
114
115    memcpy(node->dp.name, name, size);
116    node->dp.perm = perm;
117    node->dp.uid = uid;
118    node->dp.gid = gid;
119    node->dp.prefix = prefix;
120
121    list_add_tail(&dev_perms, &node->plist);
122    return 0;
123}
124
125static int get_device_perm_inner(struct perms_ *perms, const char *path,
126                                    unsigned *uid, unsigned *gid, mode_t *perm)
127{
128    int i;
129    for(i = 0; perms[i].name; i++) {
130
131        if(perms[i].prefix) {
132            if(strncmp(path, perms[i].name, strlen(perms[i].name)))
133                continue;
134        } else {
135            if(strcmp(path, perms[i].name))
136                continue;
137        }
138        *uid = perms[i].uid;
139        *gid = perms[i].gid;
140        *perm = perms[i].perm;
141        return 0;
142    }
143    return -1;
144}
145
146/* First checks for emulator specific permissions specified in /proc/cmdline. */
147static mode_t get_device_perm(const char *path, unsigned *uid, unsigned *gid)
148{
149    mode_t perm;
150    struct listnode *node;
151    struct perm_node *perm_node;
152    struct perms_ *dp;
153
154    /* search the perms list in reverse so that ueventd.$hardware can
155     * override ueventd.rc
156     */
157    list_for_each_reverse(node, &dev_perms) {
158        perm_node = node_to_item(node, struct perm_node, plist);
159        dp = &perm_node->dp;
160
161        if (dp->prefix) {
162            if (strncmp(path, dp->name, strlen(dp->name)))
163                continue;
164        } else {
165            if (strcmp(path, dp->name))
166                continue;
167        }
168        *uid = dp->uid;
169        *gid = dp->gid;
170        return dp->perm;
171    }
172    /* Default if nothing found. */
173    *uid = 0;
174    *gid = 0;
175    return 0600;
176}
177
178static void make_device(const char *path, int block, int major, int minor)
179{
180    unsigned uid;
181    unsigned gid;
182    mode_t mode;
183    dev_t dev;
184
185    mode = get_device_perm(path, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
186    dev = makedev(major, 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, *file1 = NULL, *file2 = NULL;
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(&file1, FIRMWARE_DIR1"/%s", uevent->firmware);
503    if (l == -1)
504        goto data_free_out;
505
506    l = asprintf(&file2, FIRMWARE_DIR2"/%s", uevent->firmware);
507    if (l == -1)
508        goto data_free_out;
509
510    loading_fd = open(loading, O_WRONLY);
511    if(loading_fd < 0)
512        goto file_free_out;
513
514    data_fd = open(data, O_WRONLY);
515    if(data_fd < 0)
516        goto loading_close_out;
517
518    fw_fd = open(file1, O_RDONLY);
519    if(fw_fd < 0) {
520        fw_fd = open(file2, O_RDONLY);
521        if(fw_fd < 0)
522            goto data_close_out;
523    }
524
525    if(!load_firmware(fw_fd, loading_fd, data_fd))
526        log_event_print("firmware copy success { '%s', '%s' }\n", root, uevent->firmware);
527    else
528        log_event_print("firmware copy failure { '%s', '%s' }\n", root, uevent->firmware);
529
530    close(fw_fd);
531data_close_out:
532    close(data_fd);
533loading_close_out:
534    close(loading_fd);
535file_free_out:
536    free(file1);
537    free(file2);
538data_free_out:
539    free(data);
540loading_free_out:
541    free(loading);
542root_free_out:
543    free(root);
544}
545
546static void handle_firmware_event(struct uevent *uevent)
547{
548    pid_t pid;
549    int status;
550    int ret;
551
552    if(strcmp(uevent->subsystem, "firmware"))
553        return;
554
555    if(strcmp(uevent->action, "add"))
556        return;
557
558    /* we fork, to avoid making large memory allocations in init proper */
559    pid = fork();
560    if (!pid) {
561        process_firmware_event(uevent);
562        exit(EXIT_SUCCESS);
563    } else {
564        do {
565            ret = waitpid(pid, &status, 0);
566        } while (ret == -1 && errno == EINTR);
567    }
568}
569
570#define UEVENT_MSG_LEN  1024
571void handle_device_fd()
572{
573    for(;;) {
574        char msg[UEVENT_MSG_LEN+2];
575        char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
576        struct iovec iov = {msg, sizeof(msg)};
577        struct sockaddr_nl snl;
578        struct msghdr hdr = {&snl, sizeof(snl), &iov, 1, cred_msg, sizeof(cred_msg), 0};
579
580        ssize_t n = recvmsg(device_fd, &hdr, 0);
581        if (n <= 0) {
582            break;
583        }
584
585        if ((snl.nl_groups != 1) || (snl.nl_pid != 0)) {
586            /* ignoring non-kernel netlink multicast message */
587            continue;
588        }
589
590        struct cmsghdr * cmsg = CMSG_FIRSTHDR(&hdr);
591        if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
592            /* no sender credentials received, ignore message */
593            continue;
594        }
595
596        struct ucred * cred = (struct ucred *)CMSG_DATA(cmsg);
597        if (cred->uid != 0) {
598            /* message from non-root user, ignore */
599            continue;
600        }
601
602        if(n >= UEVENT_MSG_LEN)   /* overflow -- discard */
603            continue;
604
605        msg[n] = '\0';
606        msg[n+1] = '\0';
607
608        struct uevent uevent;
609        parse_event(msg, &uevent);
610
611        handle_device_event(&uevent);
612        handle_firmware_event(&uevent);
613    }
614}
615
616/* Coldboot walks parts of the /sys tree and pokes the uevent files
617** to cause the kernel to regenerate device add events that happened
618** before init's device manager was started
619**
620** We drain any pending events from the netlink socket every time
621** we poke another uevent file to make sure we don't overrun the
622** socket's buffer.
623*/
624
625static void do_coldboot(DIR *d)
626{
627    struct dirent *de;
628    int dfd, fd;
629
630    dfd = dirfd(d);
631
632    fd = openat(dfd, "uevent", O_WRONLY);
633    if(fd >= 0) {
634        write(fd, "add\n", 4);
635        close(fd);
636        handle_device_fd();
637    }
638
639    while((de = readdir(d))) {
640        DIR *d2;
641
642        if(de->d_type != DT_DIR || de->d_name[0] == '.')
643            continue;
644
645        fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
646        if(fd < 0)
647            continue;
648
649        d2 = fdopendir(fd);
650        if(d2 == 0)
651            close(fd);
652        else {
653            do_coldboot(d2);
654            closedir(d2);
655        }
656    }
657}
658
659static void coldboot(const char *path)
660{
661    DIR *d = opendir(path);
662    if(d) {
663        do_coldboot(d);
664        closedir(d);
665    }
666}
667
668void device_init(void)
669{
670    suseconds_t t0, t1;
671    struct stat info;
672    int fd;
673
674    device_fd = open_uevent_socket();
675    if(device_fd < 0)
676        return;
677
678    fcntl(device_fd, F_SETFD, FD_CLOEXEC);
679    fcntl(device_fd, F_SETFL, O_NONBLOCK);
680
681    if (stat(coldboot_done, &info) < 0) {
682        t0 = get_usecs();
683        coldboot("/sys/class");
684        coldboot("/sys/block");
685        coldboot("/sys/devices");
686        t1 = get_usecs();
687        fd = open(coldboot_done, O_WRONLY|O_CREAT, 0000);
688        close(fd);
689        log_event_print("coldboot %ld uS\n", ((long) (t1 - t0)));
690    } else {
691        log_event_print("skipping coldboot, already done\n");
692    }
693}
694
695int get_device_fd()
696{
697    return device_fd;
698}
699