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platform_system_core/init/devices.cpp
Tom Cherry 1225a61f0a init: consider all platform devices for find_platform_device 
Certain platforms list their platform devices with a path other than
the current /devices or /devices/platform.  Additionally, sometimes
these paths are a platform device themselves.  An example are devices
with a path /devices/soc.0/... where /devices/soc.0 is also a platform
devices.

Instead of continuing to special case these path prefixes, we can
consider the entire path, given that no mmc or usb devices create
platform devices as subdevices, which they should not by their very
nature.

This keeps the symlinks for block devices named identically for
current platform devices and places them in /dev/block/<full path to
device> for devices in locations other than /devices or
/devices/platform, eg /dev/block/platform/soc.0/7824900.sdhci

This keeps the symlinks for character deviced named identically for
all cases.

Change-Id: Ifc8eedf1086db1826dbc8f7e96cdfcfa5da876b3
2015-04-23 15:04:06 -07:00

1006 lines
26 KiB
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/*
* Copyright (C) 2007-2014 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 <fnmatch.h>
#include <stddef.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 <selinux/selinux.h>
#include <selinux/label.h>
#include <selinux/android.h>
#include <selinux/avc.h>
#include <private/android_filesystem_config.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <cutils/list.h>
#include <cutils/uevent.h>
#include "devices.h"
#include "ueventd_parser.h"
#include "util.h"
#include "log.h"
#define SYSFS_PREFIX "/sys"
static const char *firmware_dirs[] = { "/etc/firmware",
"/vendor/firmware",
"/firmware/image" };
extern struct selabel_handle *sehandle;
static int device_fd = -1;
struct uevent {
const char *action;
const char *path;
const char *subsystem;
const char *firmware;
const char *partition_name;
const char *device_name;
int partition_num;
int major;
int minor;
};
struct perms_ {
char *name;
char *attr;
mode_t perm;
unsigned int uid;
unsigned int gid;
unsigned short prefix;
unsigned short wildcard;
};
struct perm_node {
struct perms_ dp;
struct listnode plist;
};
struct platform_node {
char *name;
char *path;
int path_len;
struct listnode list;
};
static list_declare(sys_perms);
static list_declare(dev_perms);
static list_declare(platform_names);
int add_dev_perms(const char *name, const char *attr,
mode_t perm, unsigned int uid, unsigned int gid,
unsigned short prefix,
unsigned short wildcard) {
struct perm_node *node = (perm_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;
node->dp.wildcard = wildcard;
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 (dp->wildcard) {
if (fnmatch(dp->name + 4, upath, FNM_PATHNAME) != 0)
continue;
} else {
if (strcmp(upath, dp->name + 4))
continue;
}
if ((strlen(upath) + strlen(dp->attr) + 6) > sizeof(buf))
break;
snprintf(buf, sizeof(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);
}
// Now fixup SELinux file labels
int len = snprintf(buf, sizeof(buf), "/sys%s", upath);
if ((len < 0) || ((size_t) len >= sizeof(buf))) {
// Overflow
return;
}
if (access(buf, F_OK) == 0) {
INFO("restorecon_recursive: %s\n", buf);
restorecon_recursive(buf);
}
}
static bool perm_path_matches(const char *path, struct perms_ *dp)
{
if (dp->prefix) {
if (strncmp(path, dp->name, strlen(dp->name)) == 0)
return true;
} else if (dp->wildcard) {
if (fnmatch(dp->name, path, FNM_PATHNAME) == 0)
return true;
} else {
if (strcmp(path, dp->name) == 0)
return true;
}
return false;
}
static mode_t get_device_perm(const char *path, const char **links,
unsigned *uid, unsigned *gid)
{
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) {
bool match = false;
perm_node = node_to_item(node, struct perm_node, plist);
dp = &perm_node->dp;
if (perm_path_matches(path, dp)) {
match = true;
} else {
if (links) {
int i;
for (i = 0; links[i]; i++) {
if (perm_path_matches(links[i], dp)) {
match = true;
break;
}
}
}
}
if (match) {
*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,
const char **links)
{
unsigned uid;
unsigned gid;
mode_t mode;
dev_t dev;
char *secontext = NULL;
mode = get_device_perm(path, links, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
if (sehandle) {
selabel_lookup_best_match(sehandle, &secontext, path, links, mode);
setfscreatecon(secontext);
}
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 (secontext) {
freecon(secontext);
setfscreatecon(NULL);
}
}
static void add_platform_device(const char *path)
{
int path_len = strlen(path);
struct platform_node *bus;
const char *name = path;
if (!strncmp(path, "/devices/", 9)) {
name += 9;
if (!strncmp(name, "platform/", 9))
name += 9;
}
INFO("adding platform device %s (%s)\n", name, path);
bus = (platform_node*) calloc(1, sizeof(struct platform_node));
bus->path = strdup(path);
bus->path_len = path_len;
bus->name = bus->path + (name - path);
list_add_tail(&platform_names, &bus->list);
}
/*
* given a path that may start with a platform device, find the length of the
* platform device prefix. If it doesn't start with a platform device, return
* 0.
*/
static struct platform_node *find_platform_device(const char *path)
{
int path_len = strlen(path);
struct listnode *node;
struct platform_node *bus;
list_for_each_reverse(node, &platform_names) {
bus = node_to_item(node, struct platform_node, list);
if ((bus->path_len < path_len) &&
(path[bus->path_len] == '/') &&
!strncmp(path, bus->path, bus->path_len))
return bus;
}
return NULL;
}
static void remove_platform_device(const char *path)
{
struct listnode *node;
struct platform_node *bus;
list_for_each_reverse(node, &platform_names) {
bus = node_to_item(node, struct platform_node, list);
if (!strcmp(path, bus->path)) {
INFO("removing platform device %s\n", bus->name);
free(bus->path);
list_remove(node);
free(bus);
return;
}
}
}
/* Given a path that may start with a PCI device, populate the supplied buffer
* with the PCI domain/bus number and the peripheral ID and return 0.
* If it doesn't start with a PCI device, or there is some error, return -1 */
static int find_pci_device_prefix(const char *path, char *buf, ssize_t buf_sz)
{
const char *start, *end;
if (strncmp(path, "/devices/pci", 12))
return -1;
/* Beginning of the prefix is the initial "pci" after "/devices/" */
start = path + 9;
/* End of the prefix is two path '/' later, capturing the domain/bus number
* and the peripheral ID. Example: pci0000:00/0000:00:1f.2 */
end = strchr(start, '/');
if (!end)
return -1;
end = strchr(end + 1, '/');
if (!end)
return -1;
/* Make sure we have enough room for the string plus null terminator */
if (end - start + 1 > buf_sz)
return -1;
strncpy(buf, start, end - start);
buf[end - start] = '\0';
return 0;
}
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;
uevent->device_name = NULL;
/* 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;
} else if(!strncmp(msg, "DEVNAME=", 8)) {
msg += 8;
uevent->device_name = msg;
}
/* advance to after the next \0 */
while(*msg++)
;
}
if (LOG_UEVENTS) {
INFO("event { '%s', '%s', '%s', '%s', %d, %d }\n",
uevent->action, uevent->path, uevent->subsystem,
uevent->firmware, uevent->major, uevent->minor);
}
}
static char **get_character_device_symlinks(struct uevent *uevent)
{
const char *parent;
char *slash;
char **links;
int link_num = 0;
int width;
struct platform_node *pdev;
pdev = find_platform_device(uevent->path);
if (!pdev)
return NULL;
links = (char**) malloc(sizeof(char *) * 2);
if (!links)
return NULL;
memset(links, 0, sizeof(char *) * 2);
/* skip "/devices/platform/<driver>" */
parent = strchr(uevent->path + pdev->path_len, '/');
if (!parent)
goto err;
if (!strncmp(parent, "/usb", 4)) {
/* skip root hub name and device. use device interface */
while (*++parent && *parent != '/');
if (*parent)
while (*++parent && *parent != '/');
if (!*parent)
goto err;
slash = strchr(++parent, '/');
if (!slash)
goto err;
width = slash - parent;
if (width <= 0)
goto err;
if (asprintf(&links[link_num], "/dev/usb/%s%.*s", uevent->subsystem, width, parent) > 0)
link_num++;
else
links[link_num] = NULL;
mkdir("/dev/usb", 0755);
}
else {
goto err;
}
return links;
err:
free(links);
return NULL;
}
static char **get_block_device_symlinks(struct uevent *uevent)
{
const char *device;
struct platform_node *pdev;
char *slash;
const char *type;
char buf[256];
char link_path[256];
int link_num = 0;
char *p;
pdev = find_platform_device(uevent->path);
if (pdev) {
device = pdev->name;
type = "platform";
} else if (!find_pci_device_prefix(uevent->path, buf, sizeof(buf))) {
device = buf;
type = "pci";
} else {
return NULL;
}
char **links = (char**) malloc(sizeof(char *) * 4);
if (!links)
return NULL;
memset(links, 0, sizeof(char *) * 4);
INFO("found %s device %s\n", type, device);
snprintf(link_path, sizeof(link_path), "/dev/block/%s/%s", type, device);
if (uevent->partition_name) {
p = strdup(uevent->partition_name);
sanitize(p);
if (strcmp(uevent->partition_name, p))
NOTICE("Linking partition '%s' as '%s'\n", uevent->partition_name, 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(uevent->path, '/');
if (asprintf(&links[link_num], "%s/%s", link_path, slash + 1) > 0)
link_num++;
else
links[link_num] = NULL;
return links;
}
static void handle_device(const char *action, const char *devpath,
const char *path, int block, int major, int minor, char **links)
{
int i;
if(!strcmp(action, "add")) {
make_device(devpath, path, block, major, minor, (const char **)links);
if (links) {
for (i = 0; links[i]; i++)
make_link(devpath, links[i]);
}
}
if(!strcmp(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 void handle_platform_device_event(struct uevent *uevent)
{
const char *path = uevent->path;
if (!strcmp(uevent->action, "add"))
add_platform_device(path);
else if (!strcmp(uevent->action, "remove"))
remove_platform_device(path);
}
static const char *parse_device_name(struct uevent *uevent, unsigned int len)
{
const char *name;
/* if it's not a /dev device, nothing else to do */
if((uevent->major < 0) || (uevent->minor < 0))
return NULL;
/* do we have a name? */
name = strrchr(uevent->path, '/');
if(!name)
return NULL;
name++;
/* too-long names would overrun our buffer */
if(strlen(name) > len) {
ERROR("DEVPATH=%s exceeds %u-character limit on filename; ignoring event\n",
name, len);
return NULL;
}
return name;
}
static void handle_block_device_event(struct uevent *uevent)
{
const char *base = "/dev/block/";
const char *name;
char devpath[96];
char **links = NULL;
name = parse_device_name(uevent, 64);
if (!name)
return;
snprintf(devpath, sizeof(devpath), "%s%s", base, name);
make_dir(base, 0755);
if (!strncmp(uevent->path, "/devices/", 9))
links = get_block_device_symlinks(uevent);
handle_device(uevent->action, devpath, uevent->path, 1,
uevent->major, uevent->minor, links);
}
#define DEVPATH_LEN 96
static bool assemble_devpath(char *devpath, const char *dirname,
const char *devname)
{
int s = snprintf(devpath, DEVPATH_LEN, "%s/%s", dirname, devname);
if (s < 0) {
ERROR("failed to assemble device path (%s); ignoring event\n",
strerror(errno));
return false;
} else if (s >= DEVPATH_LEN) {
ERROR("%s/%s exceeds %u-character limit on path; ignoring event\n",
dirname, devname, DEVPATH_LEN);
return false;
}
return true;
}
static void mkdir_recursive_for_devpath(const char *devpath)
{
char dir[DEVPATH_LEN];
char *slash;
strcpy(dir, devpath);
slash = strrchr(dir, '/');
*slash = '\0';
mkdir_recursive(dir, 0755);
}
static void handle_generic_device_event(struct uevent *uevent)
{
const char *base;
const char *name;
char devpath[DEVPATH_LEN] = {0};
char **links = NULL;
name = parse_device_name(uevent, 64);
if (!name)
return;
struct ueventd_subsystem *subsystem =
ueventd_subsystem_find_by_name(uevent->subsystem);
if (subsystem) {
const char *devname;
switch (subsystem->devname_src) {
case DEVNAME_UEVENT_DEVNAME:
devname = uevent->device_name;
break;
case DEVNAME_UEVENT_DEVPATH:
devname = name;
break;
default:
ERROR("%s subsystem's devpath option is not set; ignoring event\n",
uevent->subsystem);
return;
}
if (!assemble_devpath(devpath, subsystem->dirname, devname))
return;
mkdir_recursive_for_devpath(devpath);
} else if (!strncmp(uevent->subsystem, "usb", 3)) {
if (!strcmp(uevent->subsystem, "usb")) {
if (uevent->device_name) {
if (!assemble_devpath(devpath, "/dev", uevent->device_name))
return;
mkdir_recursive_for_devpath(devpath);
}
else {
/* 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 */
make_dir("/dev/bus", 0755);
make_dir("/dev/bus/usb", 0755);
snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d", bus_id);
make_dir(devpath, 0755);
snprintf(devpath, sizeof(devpath), "/dev/bus/usb/%03d/%03d", bus_id, device_id);
}
} else {
/* ignore other USB events */
return;
}
} else if (!strncmp(uevent->subsystem, "graphics", 8)) {
base = "/dev/graphics/";
make_dir(base, 0755);
} else if (!strncmp(uevent->subsystem, "drm", 3)) {
base = "/dev/dri/";
make_dir(base, 0755);
} else if (!strncmp(uevent->subsystem, "oncrpc", 6)) {
base = "/dev/oncrpc/";
make_dir(base, 0755);
} else if (!strncmp(uevent->subsystem, "adsp", 4)) {
base = "/dev/adsp/";
make_dir(base, 0755);
} else if (!strncmp(uevent->subsystem, "msm_camera", 10)) {
base = "/dev/msm_camera/";
make_dir(base, 0755);
} else if(!strncmp(uevent->subsystem, "input", 5)) {
base = "/dev/input/";
make_dir(base, 0755);
} else if(!strncmp(uevent->subsystem, "mtd", 3)) {
base = "/dev/mtd/";
make_dir(base, 0755);
} else if(!strncmp(uevent->subsystem, "sound", 5)) {
base = "/dev/snd/";
make_dir(base, 0755);
} else if(!strncmp(uevent->subsystem, "misc", 4) &&
!strncmp(name, "log_", 4)) {
INFO("kernel logger is deprecated\n");
base = "/dev/log/";
make_dir(base, 0755);
name += 4;
} else
base = "/dev/";
links = get_character_device_symlinks(uevent);
if (!devpath[0])
snprintf(devpath, sizeof(devpath), "%s%s", base, name);
handle_device(uevent->action, devpath, uevent->path, 0,
uevent->major, uevent->minor, links);
}
static void handle_device_event(struct uevent *uevent)
{
if (!strcmp(uevent->action,"add") || !strcmp(uevent->action, "change") || !strcmp(uevent->action, "online"))
fixup_sys_perms(uevent->path);
if (!strncmp(uevent->subsystem, "block", 5)) {
handle_block_device_event(uevent);
} else if (!strncmp(uevent->subsystem, "platform", 8)) {
handle_platform_device_event(uevent);
} else {
handle_generic_device_event(uevent);
}
}
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 int is_booting(void)
{
return access("/dev/.booting", F_OK) == 0;
}
static void process_firmware_event(struct uevent *uevent)
{
char *root, *loading, *data;
int l, loading_fd, data_fd, fw_fd;
size_t i;
int booting = is_booting();
INFO("firmware: loading '%s' for '%s'\n",
uevent->firmware, uevent->path);
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;
loading_fd = open(loading, O_WRONLY|O_CLOEXEC);
if(loading_fd < 0)
goto data_free_out;
data_fd = open(data, O_WRONLY|O_CLOEXEC);
if(data_fd < 0)
goto loading_close_out;
try_loading_again:
for (i = 0; i < ARRAY_SIZE(firmware_dirs); i++) {
char *file = NULL;
l = asprintf(&file, "%s/%s", firmware_dirs[i], uevent->firmware);
if (l == -1)
goto data_free_out;
fw_fd = open(file, O_RDONLY|O_CLOEXEC);
free(file);
if (fw_fd >= 0) {
if(!load_firmware(fw_fd, loading_fd, data_fd))
INFO("firmware: copy success { '%s', '%s' }\n", root, uevent->firmware);
else
INFO("firmware: copy failure { '%s', '%s' }\n", root, uevent->firmware);
break;
}
}
if (fw_fd < 0) {
if (booting) {
/* If we're not fully booted, we may be missing
* filesystems needed for firmware, wait and retry.
*/
usleep(100000);
booting = is_booting();
goto try_loading_again;
}
INFO("firmware: could not open '%s': %s\n", uevent->firmware, strerror(errno));
write(loading_fd, "-1", 2);
goto data_close_out;
}
close(fw_fd);
data_close_out:
close(data_fd);
loading_close_out:
close(loading_fd);
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;
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 if (pid < 0) {
ERROR("could not fork to process firmware event: %s\n", strerror(errno));
}
}
#define UEVENT_MSG_LEN 2048
void handle_device_fd()
{
char msg[UEVENT_MSG_LEN+2];
int n;
while ((n = uevent_kernel_multicast_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);
if (sehandle && selinux_status_updated() > 0) {
struct selabel_handle *sehandle2;
sehandle2 = selinux_android_file_context_handle();
if (sehandle2) {
selabel_close(sehandle);
sehandle = sehandle2;
}
}
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() {
sehandle = NULL;
if (is_selinux_enabled() > 0) {
sehandle = selinux_android_file_context_handle();
selinux_status_open(true);
}
/* is 256K enough? udev uses 16MB! */
device_fd = uevent_open_socket(256*1024, true);
if (device_fd == -1) {
return;
}
fcntl(device_fd, F_SETFL, O_NONBLOCK);
if (access(COLDBOOT_DONE, F_OK) == 0) {
NOTICE("Skipping coldboot, already done!\n");
return;
}
Timer t;
coldboot("/sys/class");
coldboot("/sys/block");
coldboot("/sys/devices");
close(open(COLDBOOT_DONE, O_WRONLY|O_CREAT|O_CLOEXEC, 0000));
NOTICE("Coldboot took %.2fs.\n", t.duration());
}
int get_device_fd()
{
return device_fd;
}
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