blob: 1a6912f820f3a74e99252888b7a536e3535a33ca [file] [log] [blame]
/*
* 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 <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <fnmatch.h>
#include <libgen.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/un.h>
#include <sys/wait.h>
#include <unistd.h>
#include <linux/netlink.h>
#include <memory>
#include <selinux/selinux.h>
#include <selinux/label.h>
#include <selinux/android.h>
#include <selinux/avc.h>
#include <private/android_filesystem_config.h>
#include <android-base/file.h>
#include <android-base/stringprintf.h>
#include <android-base/unique_fd.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;
}
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 bool match_subsystem(perms_* dp, const char* pattern,
const char* path, const char* subsystem) {
if (!pattern || !subsystem || strstr(dp->name, subsystem) == NULL) {
return false;
}
std::string subsys_path = android::base::StringPrintf(pattern, subsystem, basename(path));
return perm_path_matches(subsys_path.c_str(), dp);
}
static void fixup_sys_perms(const char* upath, const char* subsystem) {
// upaths omit the "/sys" that paths in this list
// contain, so we prepend it...
std::string path = std::string(SYSFS_PREFIX) + upath;
listnode* node;
list_for_each(node, &sys_perms) {
perms_* dp = &(node_to_item(node, perm_node, plist))->dp;
if (match_subsystem(dp, SYSFS_PREFIX "/class/%s/%s", path.c_str(), subsystem)) {
; // matched
} else if (match_subsystem(dp, SYSFS_PREFIX "/bus/%s/devices/%s", path.c_str(), subsystem)) {
; // matched
} else if (!perm_path_matches(path.c_str(), dp)) {
continue;
}
std::string attr_file = path + "/" + dp->attr;
LOG(INFO) << "fixup " << attr_file
<< " " << dp->uid << " " << dp->gid << " " << std::oct << dp->perm;
chown(attr_file.c_str(), dp->uid, dp->gid);
chmod(attr_file.c_str(), dp->perm);
}
if (access(path.c_str(), F_OK) == 0) {
LOG(VERBOSE) << "restorecon_recursive: " << path;
restorecon_recursive(path.c_str());
}
}
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 (selabel_lookup_best_match(sehandle, &secontext, path, links, mode)) {
PLOG(ERROR) << "Device '" << path << "' not created; cannot find SELinux label";
return;
}
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);
/* If the node already exists update its SELinux label to handle cases when
* it was created with the wrong context during coldboot procedure. */
if (mknod(path, mode, dev) && (errno == EEXIST)) {
char* fcon = nullptr;
int rc = lgetfilecon(path, &fcon);
if (rc < 0) {
PLOG(ERROR) << "Cannot get SELinux label on '" << path << "' device";
goto out;
}
bool different = strcmp(fcon, secontext) != 0;
freecon(fcon);
if (different && lsetfilecon(path, secontext)) {
PLOG(ERROR) << "Cannot set '" << secontext << "' SELinux label on '" << path << "' device";
}
}
out:
chown(path, uid, -1);
setegid(AID_ROOT);
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;
}
LOG(VERBOSE) << "adding platform device " << 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)) {
LOG(INFO) << "removing platform device " << 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) {
LOG(INFO) << android::base::StringPrintf("event { '%s', '%s', '%s', '%s', %d, %d }",
uevent->action, uevent->path, uevent->subsystem,
uevent->firmware, uevent->major, uevent->minor);
}
}
static char **get_character_device_symlinks(struct uevent *uevent)
{
const char *parent;
const 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;
const 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);
LOG(INFO) << "found " << type << " device " << 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)) {
LOG(VERBOSE) << "Linking partition '" << uevent->partition_name << "' as '" << 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 make_link_init(const char* oldpath, const char* newpath) {
const char* slash = strrchr(newpath, '/');
if (!slash) return;
if (mkdir_recursive(dirname(newpath), 0755)) {
PLOG(ERROR) << "Failed to create directory " << dirname(newpath);
}
if (symlink(oldpath, newpath) && errno != EEXIST) {
PLOG(ERROR) << "Failed to symlink " << oldpath << " to " << newpath;
}
}
static void remove_link(const char* oldpath, const char* newpath) {
std::string path;
if (android::base::Readlink(newpath, &path) && path == oldpath) unlink(newpath);
}
static void handle_device(const char *action, const char *devpath,
const char *path, int block, int major, int minor, char **links)
{
if(!strcmp(action, "add")) {
make_device(devpath, path, block, major, minor, (const char **)links);
if (links) {
for (int i = 0; links[i]; i++) {
make_link_init(devpath, links[i]);
}
}
}
if(!strcmp(action, "remove")) {
if (links) {
for (int i = 0; links[i]; i++) {
remove_link(devpath, links[i]);
}
}
unlink(devpath);
}
if (links) {
for (int 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) {
LOG(ERROR) << "DEVPATH=" << name << " exceeds " << len << "-character limit on filename; ignoring event";
return NULL;
}
return name;
}
#define DEVPATH_LEN 96
#define MAX_DEV_NAME 64
static void handle_block_device_event(struct uevent *uevent)
{
const char *base = "/dev/block/";
const char *name;
char devpath[DEVPATH_LEN];
char **links = NULL;
name = parse_device_name(uevent, MAX_DEV_NAME);
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);
}
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) {
PLOG(ERROR) << "failed to assemble device path; ignoring event";
return false;
} else if (s >= DEVPATH_LEN) {
LOG(ERROR) << dirname << "/" << devname
<< " exceeds " << DEVPATH_LEN << "-character limit on path; ignoring event";
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, MAX_DEV_NAME);
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:
LOG(ERROR) << uevent->subsystem << " subsystem's devpath option is not set; ignoring event";
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)) {
LOG(INFO) << "kernel logger is deprecated";
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, uevent->subsystem);
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;
}
if (!android::base::WriteFully(data_fd, buf, nr)) {
ret = -1;
break;
}
len_to_copy -= nr;
}
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();
LOG(INFO) << "firmware: loading '" << uevent->firmware << "' for '" << 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 < arraysize(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)) {
LOG(INFO) << "firmware: copy success { '" << root << "', '" << uevent->firmware << "' }";
} else {
LOG(ERROR) << "firmware: copy failure { '" << 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;
}
PLOG(ERROR) << "firmware: could not open '" << uevent->firmware << "'";
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) {
PLOG(ERROR) << "could not fork to process firmware event";
}
}
#define UEVENT_MSG_LEN 2048
static inline void handle_device_fd_with(void (handle_uevent)(struct uevent*))
{
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);
handle_uevent(&uevent);
}
}
void handle_device_fd()
{
handle_device_fd_with(
[](struct uevent *uevent) {
if (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)
{
std::unique_ptr<DIR, decltype(&closedir)> d(opendir(path), closedir);
if(d) {
do_coldboot(d.get());
}
}
static void early_uevent_handler(struct uevent *uevent, const char *base, bool is_block)
{
const char *name;
char devpath[DEVPATH_LEN];
if (is_block && strncmp(uevent->subsystem, "block", 5))
return;
name = parse_device_name(uevent, MAX_DEV_NAME);
if (!name) {
LOG(ERROR) << "Failed to parse dev name from uevent: " << uevent->action
<< " " << uevent->partition_name << " " << uevent->partition_num
<< " " << uevent->major << ":" << uevent->minor;
return;
}
snprintf(devpath, sizeof(devpath), "%s%s", base, name);
make_dir(base, 0755);
dev_t dev = makedev(uevent->major, uevent->minor);
mode_t mode = 0600 | (is_block ? S_IFBLK : S_IFCHR);
mknod(devpath, mode, dev);
}
void early_create_dev(const std::string& syspath, early_device_type dev_type)
{
android::base::unique_fd dfd(open(syspath.c_str(), O_RDONLY));
if (dfd < 0) {
LOG(ERROR) << "Failed to open " << syspath;
return;
}
android::base::unique_fd fd(openat(dfd, "uevent", O_WRONLY));
if (fd < 0) {
LOG(ERROR) << "Failed to open " << syspath << "/uevent";
return;
}
fcntl(device_fd, F_SETFL, O_NONBLOCK);
write(fd, "add\n", 4);
handle_device_fd_with(dev_type == EARLY_BLOCK_DEV ?
[](struct uevent *uevent) {
early_uevent_handler(uevent, "/dev/block/", true);
} :
[](struct uevent *uevent) {
early_uevent_handler(uevent, "/dev/", false);
});
}
int early_device_socket_open() {
device_fd = uevent_open_socket(256*1024, true);
return device_fd < 0;
}
void early_device_socket_close() {
close(device_fd);
}
void device_init() {
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) {
LOG(VERBOSE) << "Skipping coldboot, already done!";
return;
}
Timer t;
coldboot("/sys/class");
coldboot("/sys/block");
coldboot("/sys/devices");
close(open(COLDBOOT_DONE, O_WRONLY|O_CREAT|O_CLOEXEC, 0000));
LOG(INFO) << "Coldboot took " << t.duration() << "s.";
}
int get_device_fd()
{
return device_fd;
}