devices.c

Android 一些工具

/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>

#include <fcntl.h>
#include <dirent.h>
#include <unistd.h>
#include <string.h>

#include <sys/socket.h>
#include <sys/un.h>
#include <linux/netlink.h>
#include <private/android_filesystem_config.h>
#include <sys/time.h>
#include <asm/page.h>

#include "init.h"
#include "devices.h"

#define CMDLINE_PREFIX  "/dev"
#define SYSFS_PREFIX    "/sys"
#define FIRMWARE_DIR    "/etc/firmware"
#define MAX_QEMU_PERM 6

struct uevent {
    const char *action;
    const char *path;
    const char *subsystem;
    const char *firmware;
    int major;
    int minor;
};

static int open_uevent_socket(void)
{
    struct sockaddr_nl addr;
    int sz = 64*1024; // XXX larger? udev uses 16MB!
    int s;

    memset(&addr, 0, sizeof(addr));
    addr.nl_family = AF_NETLINK;
    addr.nl_pid = getpid();
    addr.nl_groups = 0xffffffff;

    s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
    if(s < 0)
        return -1;

    setsockopt(s, SOL_SOCKET, SO_RCVBUFFORCE, &sz, sizeof(sz));

    if(bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
        close(s);
        return -1;
    }

    return s;
}

struct perms_ {
    char *name;
    mode_t perm;
    unsigned int uid;
    unsigned int gid;
    unsigned short prefix;
};
static struct perms_ devperms[] = {
    { "/dev/null",          0666,   AID_ROOT,       AID_ROOT,       0 },
    { "/dev/zero",          0666,   AID_ROOT,       AID_ROOT,       0 },
    { "/dev/full",          0666,   AID_ROOT,       AID_ROOT,       0 },
    { "/dev/ptmx",          0666,   AID_ROOT,       AID_ROOT,       0 },
    { "/dev/tty",           0666,   AID_ROOT,       AID_ROOT,       0 },
    { "/dev/random",        0666,   AID_ROOT,       AID_ROOT,       0 },
    { "/dev/urandom",       0666,   AID_ROOT,       AID_ROOT,       0 },
    { "/dev/ashmem",        0666,   AID_ROOT,       AID_ROOT,       0 },
    { "/dev/binder",        0666,   AID_ROOT,       AID_ROOT,       0 },

	    /* logger should be world writable (for logging) but not readable */
    { "/dev/log/",          0662,   AID_ROOT,       AID_LOG,        1 },

        /* these should not be world writable */
    { "/dev/android_adb",   0660,   AID_ADB,        AID_ADB,        0 },
    { "/dev/android_adb_enable",   0660,   AID_ADB,        AID_ADB,        0 },
    { "/dev/ttyMSM0",       0660,   AID_BLUETOOTH,  AID_BLUETOOTH,  0 },
    { "/dev/alarm",         0664,   AID_SYSTEM,     AID_RADIO,      0 },
    { "/dev/tty0",          0666,   AID_ROOT,       AID_SYSTEM,     0 },
    { "/dev/graphics/",     0660,   AID_ROOT,       AID_GRAPHICS,   1 },
    { "/dev/hw3d",          0660,   AID_SYSTEM,     AID_GRAPHICS,   0 },
    { "/dev/input/",        0660,   AID_ROOT,       AID_INPUT,      1 },
    { "/dev/eac",           0660,   AID_ROOT,       AID_AUDIO,      0 },
    { "/dev/cam",           0660,   AID_ROOT,       AID_CAMERA,     0 },
    { "/dev/pmem",          0660,   AID_SYSTEM,     AID_GRAPHICS,   0 },
    { "/dev/pmem_gpu",      0660,   AID_SYSTEM,     AID_GRAPHICS,   1 },
    { "/dev/pmem_adsp",     0660,   AID_SYSTEM,     AID_AUDIO,      1 },
    { "/dev/pmem_camera",   0660,   AID_SYSTEM,     AID_CAMERA,     1 },
    { "/dev/oncrpc/",       0660,   AID_ROOT,       AID_SYSTEM,     1 },
    { "/dev/adsp/",         0660,   AID_SYSTEM,     AID_AUDIO,      1 },
    { "/dev/mt9t013",       0660,   AID_SYSTEM,     AID_SYSTEM,     0 },
    { "/dev/akm8976_daemon",0640,   AID_COMPASS,    AID_SYSTEM,     0 },
    { "/dev/akm8976_aot",   0640,   AID_COMPASS,    AID_SYSTEM,     0 },
    { "/dev/akm8976_pffd",  0640,   AID_COMPASS,    AID_SYSTEM,     0 },
    { "/dev/msm_pcm_out",   0660,   AID_SYSTEM,     AID_AUDIO,      1 },
    { "/dev/msm_pcm_in",    0660,   AID_SYSTEM,     AID_AUDIO,      1 },
    { "/dev/msm_pcm_ctl",   0660,   AID_SYSTEM,     AID_AUDIO,      1 },
    { "/dev/msm_mp3",       0660,   AID_SYSTEM,     AID_AUDIO,      1 },
    { "/dev/smd0",          0640,   AID_RADIO,      AID_RADIO,      0 },
    { "/dev/qmi",           0640,   AID_RADIO,      AID_RADIO,      0 },
    { "/dev/qmi0",          0640,   AID_RADIO,      AID_RADIO,      0 },
    { "/dev/qmi1",          0640,   AID_RADIO,      AID_RADIO,      0 },
    { "/dev/qmi2",          0640,   AID_RADIO,      AID_RADIO,      0 },
    { "/dev/htc-acoustic",  0640,   AID_RADIO,      AID_RADIO,      0 },
    { NULL, 0, 0, 0, 0 },
};

/* devperms_partners list and perm_node are for hardware specific /dev entries */
struct perm_node {
    struct perms_ dp;
    struct listnode plist;
};
list_declare(devperms_partners);

/*
 * Permission override when in emulator mode, must be parsed before
 * system properties is initalized.
 */
static int qemu_perm_count;
static struct perms_ qemu_perms[MAX_QEMU_PERM + 1];

int add_devperms_partners(const char *name, mode_t perm, unsigned int uid,
                        unsigned int gid, unsigned short prefix) {
    int size;
    struct perm_node *node = malloc(sizeof (struct perm_node));
    if (!node)
        return -ENOMEM;

    size = strlen(name) + 1;
    if ((node->dp.name = malloc(size)) == NULL)
        return -ENOMEM;

    memcpy(node->dp.name, name, size);
    node->dp.perm = perm;
    node->dp.uid = uid;
    node->dp.gid = gid;
    node->dp.prefix = prefix;

    list_add_tail(&devperms_partners, &node->plist);
    return 0;
}

void qemu_init(void) {
    qemu_perm_count = 0;
    memset(&qemu_perms, 0, sizeof(qemu_perms));
}

static int qemu_perm(const char* name, mode_t perm, unsigned int uid,
                         unsigned int gid, unsigned short prefix)
{
    char *buf;
    if (qemu_perm_count == MAX_QEMU_PERM)
        return -ENOSPC;

    buf = malloc(strlen(name) + 1);
    if (!buf)
        return -errno;

    strlcpy(buf, name, strlen(name) + 1);
    qemu_perms[qemu_perm_count].name = buf;
    qemu_perms[qemu_perm_count].perm = perm;
    qemu_perms[qemu_perm_count].uid = uid;
    qemu_perms[qemu_perm_count].gid = gid;
    qemu_perms[qemu_perm_count].prefix = prefix;

    qemu_perm_count++;
    return 0;
}

/* Permission overrides for emulator that are parsed from /proc/cmdline. */
void qemu_cmdline(const char* name, const char *value)
{
    char *buf;
    if (!strcmp(name, "android.ril")) {
        /* cmd line params currently assume /dev/ prefix */
        if (asprintf(&buf, CMDLINE_PREFIX"/%s", value) == -1) {
            return;
        }
        INFO("nani- buf:: %s\n", buf);
        qemu_perm(buf, 0660, AID_RADIO, AID_ROOT, 0);
    }
}

static int get_device_perm_inner(struct perms_ *perms, const char *path,
                                    unsigned *uid, unsigned *gid, mode_t *perm)
{
    int i;
    for(i = 0; perms[i].name; i++) {

        if(perms[i].prefix) {
            if(strncmp(path, perms[i].name, strlen(perms[i].name)))
                continue;
        } else {
            if(strcmp(path, perms[i].name))
                continue;
        }
        *uid = perms[i].uid;
        *gid = perms[i].gid;
        *perm = perms[i].perm;
        return 0;
    }
    return -1;
}

/* First checks for emulator specific permissions specified in /proc/cmdline. */
static mode_t get_device_perm(const char *path, unsigned *uid, unsigned *gid)
{
    mode_t perm;

    if (get_device_perm_inner(qemu_perms, path, uid, gid, &perm) == 0) {
        return perm;
    } else if (get_device_perm_inner(devperms, path, uid, gid, &perm) == 0) {
        return perm;
    } else {
        struct listnode *node;
        struct perm_node *perm_node;
        struct perms_ *dp;

        /* Check partners list. */
        list_for_each(node, &devperms_partners) {
            perm_node = node_to_item(node, struct perm_node, plist);
            dp = &perm_node->dp;

            if (dp->prefix) {
                if (strncmp(path, dp->name, strlen(dp->name)))
                    continue;
            } else {
                if (strcmp(path, dp->name))
                    continue;
            }
            /* Found perm in partner list. */
            *uid = dp->uid;
            *gid = dp->gid;
            return dp->perm;
        }
        /* Default if nothing found. */
        *uid = 0;
        *gid = 0;
        return 0600;
    }
}

static void make_device(const char *path, int block, int major, int minor)
{
    unsigned uid;
    unsigned gid;
    mode_t mode;
    dev_t dev;

    if(major > 255 || minor > 255)
        return;

    mode = get_device_perm(path, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
    dev = (major << 8) | minor;
    mknod(path, mode, dev);
    chown(path, uid, gid);
}

#ifdef LOG_UEVENTS

static inline suseconds_t get_usecs(void)
{
    struct timeval tv;
    gettimeofday(&tv, 0);
    return tv.tv_sec * (suseconds_t) 1000000 + tv.tv_usec;
}

#define log_event_print(x...) INFO(x)

#else

#define log_event_print(fmt, args...)   do { } while (0)
#define get_usecs()                     0

#endif

static void parse_event(const char *msg, struct uevent *uevent)
{
    uevent->action = "";
    uevent->path = "";
    uevent->subsystem = "";
    uevent->firmware = "";
    uevent->major = -1;
    uevent->minor = -1;

        /* currently ignoring SEQNUM */
    while(*msg) {
        if(!strncmp(msg, "ACTION=", 7)) {