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platform_system_core/init/devices.c
Vernon Tang 3f582e92f0 Fold uevent message origin checking from init into libcutils. 
Change-Id: I7cbc0cb840d1b4962e6c360fdad9a9c0ce20e87b
2011-04-28 05:16:21 +10:00

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/*
* 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 <sys/wait.h>
#include <cutils/uevent.h>
#include "devices.h"
#include "util.h"
#include "log.h"
#include "list.h"
#define SYSFS_PREFIX "/sys"
#define FIRMWARE_DIR1 "/etc/firmware"
#define FIRMWARE_DIR2 "/vendor/firmware"
static int device_fd = -1;
struct uevent {
const char *action;
const char *path;
const char *subsystem;
const char *firmware;
const char *partition_name;
int partition_num;
int major;
int minor;
};
static int open_uevent_socket(void)
{
struct sockaddr_nl addr;
int sz = 64*1024; // XXX larger? udev uses 16MB!
int on = 1;
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));
setsockopt(s, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
if(bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
close(s);
return -1;
}
return s;
}
struct perms_ {
char *name;
char *attr;
mode_t perm;
unsigned int uid;
unsigned int gid;
unsigned short prefix;
};
struct perm_node {
struct perms_ dp;
struct listnode plist;
};
static list_declare(sys_perms);
static list_declare(dev_perms);
int add_dev_perms(const char *name, const char *attr,
mode_t perm, unsigned int uid, unsigned int gid,
unsigned short prefix) {
struct perm_node *node = calloc(1, sizeof(*node));
if (!node)
return -ENOMEM;
node->dp.name = strdup(name);
if (!node->dp.name)
return -ENOMEM;
if (attr) {
node->dp.attr = strdup(attr);
if (!node->dp.attr)
return -ENOMEM;
}
node->dp.perm = perm;
node->dp.uid = uid;
node->dp.gid = gid;
node->dp.prefix = prefix;
if (attr)
list_add_tail(&sys_perms, &node->plist);
else
list_add_tail(&dev_perms, &node->plist);
return 0;
}
void fixup_sys_perms(const char *upath)
{
char buf[512];
struct listnode *node;
struct perms_ *dp;
/* upaths omit the "/sys" that paths in this list
* contain, so we add 4 when comparing...
*/
list_for_each(node, &sys_perms) {
dp = &(node_to_item(node, struct perm_node, plist))->dp;
if (dp->prefix) {
if (strncmp(upath, dp->name + 4, strlen(dp->name + 4)))
continue;
} else {
if (strcmp(upath, dp->name + 4))
continue;
}
if ((strlen(upath) + strlen(dp->attr) + 6) > sizeof(buf))
return;
sprintf(buf,"/sys%s/%s", upath, dp->attr);
INFO("fixup %s %d %d 0%o\n", buf, dp->uid, dp->gid, dp->perm);
chown(buf, dp->uid, dp->gid);
chmod(buf, dp->perm);
}
}
static mode_t get_device_perm(const char *path, unsigned *uid, unsigned *gid)
{
mode_t perm;
struct listnode *node;
struct perm_node *perm_node;
struct perms_ *dp;
/* search the perms list in reverse so that ueventd.$hardware can
* override ueventd.rc
*/
list_for_each_reverse(node, &dev_perms) {
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;
}
*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,
const char *upath,
int block, int major, int minor)
{
unsigned uid;
unsigned gid;
mode_t mode;
dev_t dev;
mode = get_device_perm(path, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
dev = makedev(major, minor);
/* Temporarily change egid to avoid race condition setting the gid of the
* device node. Unforunately changing the euid would prevent creation of
* some device nodes, so the uid has to be set with chown() and is still
* racy. Fixing the gid race at least fixed the issue with system_server
* opening dynamic input devices under the AID_INPUT gid. */
setegid(gid);
mknod(path, mode, dev);
chown(path, uid, -1);
setegid(AID_ROOT);
}
#if 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;
uevent->partition_name = NULL;
uevent->partition_num = -1;
/* currently ignoring SEQNUM */
while(*msg) {
if(!strncmp(msg, "ACTION=", 7)) {
msg += 7;
uevent->action = msg;
} else if(!strncmp(msg, "DEVPATH=", 8)) {
msg += 8;
uevent->path = msg;
} else if(!strncmp(msg, "SUBSYSTEM=", 10)) {
msg += 10;
uevent->subsystem = msg;
} else if(!strncmp(msg, "FIRMWARE=", 9)) {
msg += 9;
uevent->firmware = msg;
} else if(!strncmp(msg, "MAJOR=", 6)) {
msg += 6;
uevent->major = atoi(msg);
} else if(!strncmp(msg, "MINOR=", 6)) {
msg += 6;
uevent->minor = atoi(msg);
} else if(!strncmp(msg, "PARTN=", 6)) {
msg += 6;
uevent->partition_num = atoi(msg);
} else if(!strncmp(msg, "PARTNAME=", 9)) {
msg += 9;
uevent->partition_name = msg;
}
/* advance to after the next \0 */
while(*msg++)
;
}
log_event_print("event { '%s', '%s', '%s', '%s', %d, %d }\n",
uevent->action, uevent->path, uevent->subsystem,
uevent->firmware, uevent->major, uevent->minor);
}
static char **parse_platform_block_device(struct uevent *uevent)
{
const char *driver;
const char *path;
char *slash;
int width;
char buf[256];
char link_path[256];
int fd;
int link_num = 0;
int ret;
char *p;
unsigned int size;
struct stat info;
char **links = malloc(sizeof(char *) * 4);
if (!links)
return NULL;
memset(links, 0, sizeof(char *) * 4);
/* Drop "/devices/platform/" */
path = uevent->path;
driver = path + 18;
slash = strchr(driver, '/');
if (!slash)
goto err;
width = slash - driver;
if (width <= 0)
goto err;
snprintf(link_path, sizeof(link_path), "/dev/block/platform/%.*s",
width, driver);
if (uevent->partition_name) {
p = strdup(uevent->partition_name);
sanitize(p);
if (asprintf(&links[link_num], "%s/by-name/%s", link_path, p) > 0)
link_num++;
else
links[link_num] = NULL;
free(p);
}
if (uevent->partition_num >= 0) {
if (asprintf(&links[link_num], "%s/by-num/p%d", link_path, uevent->partition_num) > 0)
link_num++;
else
links[link_num] = NULL;
}
slash = strrchr(path, '/');
if (asprintf(&links[link_num], "%s/%s", link_path, slash + 1) > 0)
link_num++;
else
links[link_num] = NULL;
return links;
err:
free(links);
return NULL;
}
static void handle_device_event(struct uevent *uevent)
{
char devpath[96];
int devpath_ready = 0;
char *base, *name;
char **links = NULL;
int block;
int i;
if (!strcmp(uevent->action,"add"))
fixup_sys_perms(uevent->path);
/* if it's not a /dev device, nothing else to do */
if((uevent->major < 0) || (uevent->minor < 0))
return;
/* do we have a name? */
name = strrchr(uevent->path, '/');
if(!name)
return;
name++;
/* too-long names would overrun our buffer */
if(strlen(name) > 64)
return;
/* are we block or char? where should we live? */
if(!strncmp(uevent->subsystem, "block", 5)) {
block = 1;
base = "/dev/block/";
mkdir(base, 0755);
if (!strncmp(uevent->path, "/devices/platform/", 18))
links = parse_platform_block_device(uevent);
} else {
block = 0;
/* this should probably be configurable somehow */
if (!strncmp(uevent->subsystem, "usb", 3)) {
if (!strcmp(uevent->subsystem, "usb")) {
/* This imitates the file system that would be created
* if we were using devfs instead.
* Minors are broken up into groups of 128, starting at "001"
*/
int bus_id = uevent->minor / 128 + 1;
int device_id = uevent->minor % 128 + 1;
/* build directories */
mkdir("/dev/bus", 0755);
mkdir("/dev/bus/usb", 0755);
snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d", bus_id);
mkdir(devpath, 0755);
snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d/%03d", bus_id, device_id);
devpath_ready = 1;
} else {
/* ignore other USB events */
return;
}
} else if (!strncmp(uevent->subsystem, "graphics", 8)) {
base = "/dev/graphics/";
mkdir(base, 0755);
} else if (!strncmp(uevent->subsystem, "oncrpc", 6)) {
base = "/dev/oncrpc/";
mkdir(base, 0755);
} else if (!strncmp(uevent->subsystem, "adsp", 4)) {
base = "/dev/adsp/";
mkdir(base, 0755);
} else if (!strncmp(uevent->subsystem, "msm_camera", 10)) {
base = "/dev/msm_camera/";
mkdir(base, 0755);
} else if(!strncmp(uevent->subsystem, "input", 5)) {
base = "/dev/input/";
mkdir(base, 0755);
} else if(!strncmp(uevent->subsystem, "mtd", 3)) {
base = "/dev/mtd/";
mkdir(base, 0755);
} else if(!strncmp(uevent->subsystem, "sound", 5)) {
base = "/dev/snd/";
mkdir(base, 0755);
} else if(!strncmp(uevent->subsystem, "misc", 4) &&
!strncmp(name, "log_", 4)) {
base = "/dev/log/";
mkdir(base, 0755);
name += 4;
} else
base = "/dev/";
}
if (!devpath_ready)
snprintf(devpath, sizeof(devpath), "%s%s", base, name);
if(!strcmp(uevent->action, "add")) {
make_device(devpath, uevent->path, block, uevent->major, uevent->minor);
if (links) {
for (i = 0; links[i]; i++)
make_link(devpath, links[i]);
}
}
if(!strcmp(uevent->action, "remove")) {
if (links) {
for (i = 0; links[i]; i++)
remove_link(devpath, links[i]);
}
unlink(devpath);
}
if (links) {
for (i = 0; links[i]; i++)
free(links[i]);
free(links);
}
}
static int load_firmware(int fw_fd, int loading_fd, int data_fd)
{
struct stat st;
long len_to_copy;
int ret = 0;
if(fstat(fw_fd, &st) < 0)
return -1;
len_to_copy = st.st_size;
write(loading_fd, "1", 1); /* start transfer */
while (len_to_copy > 0) {
char buf[PAGE_SIZE];
ssize_t nr;
nr = read(fw_fd, buf, sizeof(buf));
if(!nr)
break;
if(nr < 0) {
ret = -1;
break;
}
len_to_copy -= nr;
while (nr > 0) {
ssize_t nw = 0;
nw = write(data_fd, buf + nw, nr);
if(nw <= 0) {
ret = -1;
goto out;
}
nr -= nw;
}
}
out:
if(!ret)
write(loading_fd, "0", 1); /* successful end of transfer */
else
write(loading_fd, "-1", 2); /* abort transfer */
return ret;
}
static void process_firmware_event(struct uevent *uevent)
{
char *root, *loading, *data, *file1 = NULL, *file2 = NULL;
int l, loading_fd, data_fd, fw_fd;
log_event_print("firmware event { '%s', '%s' }\n",
uevent->path, uevent->firmware);
l = asprintf(&root, SYSFS_PREFIX"%s/", uevent->path);
if (l == -1)
return;
l = asprintf(&loading, "%sloading", root);
if (l == -1)
goto root_free_out;
l = asprintf(&data, "%sdata", root);
if (l == -1)
goto loading_free_out;
l = asprintf(&file1, FIRMWARE_DIR1"/%s", uevent->firmware);
if (l == -1)
goto data_free_out;
l = asprintf(&file2, FIRMWARE_DIR2"/%s", uevent->firmware);
if (l == -1)
goto data_free_out;
loading_fd = open(loading, O_WRONLY);
if(loading_fd < 0)
goto file_free_out;
data_fd = open(data, O_WRONLY);
if(data_fd < 0)
goto loading_close_out;
fw_fd = open(file1, O_RDONLY);
if(fw_fd < 0) {
fw_fd = open(file2, O_RDONLY);
if(fw_fd < 0)
goto data_close_out;
}
if(!load_firmware(fw_fd, loading_fd, data_fd))
log_event_print("firmware copy success { '%s', '%s' }\n", root, uevent->firmware);
else
log_event_print("firmware copy failure { '%s', '%s' }\n", root, uevent->firmware);
close(fw_fd);
data_close_out:
close(data_fd);
loading_close_out:
close(loading_fd);
file_free_out:
free(file1);
free(file2);
data_free_out:
free(data);
loading_free_out:
free(loading);
root_free_out:
free(root);
}
static void handle_firmware_event(struct uevent *uevent)
{
pid_t pid;
int status;
int ret;
if(strcmp(uevent->subsystem, "firmware"))
return;
if(strcmp(uevent->action, "add"))
return;
/* we fork, to avoid making large memory allocations in init proper */
pid = fork();
if (!pid) {
process_firmware_event(uevent);
exit(EXIT_SUCCESS);
} else {
do {
ret = waitpid(pid, &status, 0);
} while (ret == -1 && errno == EINTR);
}
}
#define UEVENT_MSG_LEN 1024
void handle_device_fd()
{
char msg[UEVENT_MSG_LEN+2];
int n;
while ((n = uevent_checked_recv(device_fd, msg, UEVENT_MSG_LEN)) > 0) {
if(n >= UEVENT_MSG_LEN) /* overflow -- discard */
continue;
msg[n] = '\0';
msg[n+1] = '\0';
struct uevent uevent;
parse_event(msg, &uevent);
handle_device_event(&uevent);
handle_firmware_event(&uevent);
}
}
/* Coldboot walks parts of the /sys tree and pokes the uevent files
** to cause the kernel to regenerate device add events that happened
** before init's device manager was started
**
** We drain any pending events from the netlink socket every time
** we poke another uevent file to make sure we don't overrun the
** socket's buffer.
*/
static void do_coldboot(DIR *d)
{
struct dirent *de;
int dfd, fd;
dfd = dirfd(d);
fd = openat(dfd, "uevent", O_WRONLY);
if(fd >= 0) {
write(fd, "add\n", 4);
close(fd);
handle_device_fd();
}
while((de = readdir(d))) {
DIR *d2;
if(de->d_type != DT_DIR || de->d_name[0] == '.')
continue;
fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
if(fd < 0)
continue;
d2 = fdopendir(fd);
if(d2 == 0)
close(fd);
else {
do_coldboot(d2);
closedir(d2);
}
}
}
static void coldboot(const char *path)
{
DIR *d = opendir(path);
if(d) {
do_coldboot(d);
closedir(d);
}
}
void device_init(void)
{
suseconds_t t0, t1;
struct stat info;
int fd;
device_fd = open_uevent_socket();
if(device_fd < 0)
return;
fcntl(device_fd, F_SETFD, FD_CLOEXEC);
fcntl(device_fd, F_SETFL, O_NONBLOCK);
if (stat(coldboot_done, &info) < 0) {
t0 = get_usecs();
coldboot("/sys/class");
coldboot("/sys/block");
coldboot("/sys/devices");
t1 = get_usecs();
fd = open(coldboot_done, O_WRONLY|O_CREAT, 0000);
close(fd);
log_event_print("coldboot %ld uS\n", ((long) (t1 - t0)));
} else {
log_event_print("skipping coldboot, already done\n");
}
}
int get_device_fd()
{
return device_fd;
}
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