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platform_system_core/init/devices.cpp
Tom Cherry 3fa467338f ueventd: Fix up string handling in handle_*_device_event() 
Bug: 36250207

Test: Boot bullhead
Test: Boot sailfish, observe no boot time regression
Test: init unit tests

Change-Id: Ie5ec609a3f74bb03f5920734ada4d7de57508de4
2017-04-12 16:36:53 -07:00

950 lines
29 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 <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <fnmatch.h>
#include <libgen.h>
#include <linux/netlink.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/sendfile.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/un.h>
#include <sys/wait.h>
#include <unistd.h>
#include <algorithm>
#include <memory>
#include <string>
#include <thread>
#include <vector>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <android-base/unique_fd.h>
#include <cutils/list.h>
#include <cutils/uevent.h>
#include <private/android_filesystem_config.h>
#include <selinux/android.h>
#include <selinux/avc.h>
#include <selinux/label.h>
#include <selinux/selinux.h>
#include "devices.h"
#include "ueventd_parser.h"
#include "util.h"
#define SYSFS_PREFIX "/sys"
static const char *firmware_dirs[] = { "/etc/firmware",
"/vendor/firmware",
"/firmware/image" };
extern struct selabel_handle *sehandle;
static android::base::unique_fd device_fd;
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) {
free(node);
return -ENOMEM;
}
if (attr) {
node->dp.attr = strdup(attr);
if (!node->dp.attr) {
free(node->dp.name);
free(node);
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(path.c_str(), SELINUX_ANDROID_RESTORECON_RECURSE);
}
}
static mode_t get_device_perm(const char* path, const std::vector<std::string>& 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) {
perm_node = node_to_item(node, struct perm_node, plist);
dp = &perm_node->dp;
if (perm_path_matches(path, dp) ||
std::any_of(links.begin(), links.end(),
[dp](const auto& link) { return perm_path_matches(link.c_str(), dp); })) {
*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 std::vector<std::string>& 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) {
std::vector<const char*> c_links;
for (const auto& link : links) {
c_links.emplace_back(link.c_str());
}
c_links.emplace_back(nullptr);
if (selabel_lookup_best_match(sehandle, &secontext, path, &c_links[0], 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. */
if (setegid(gid)) {
PLOG(ERROR) << "setegid(" << gid << ") for " << path << " device failed";
goto out;
}
/* 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) && secontext) {
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);
if (setegid(AID_ROOT)) {
PLOG(FATAL) << "setegid(AID_ROOT) failed";
}
if (secontext) {
freecon(secontext);
setfscreatecon(NULL);
}
}
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;
}
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;
}
}
}
static void destroy_platform_devices() {
struct listnode* node;
struct listnode* n;
struct platform_node* bus;
list_for_each_safe(node, n, &platform_names) {
list_remove(node);
bus = node_to_item(node, struct platform_node, list);
free(bus->path);
free(bus);
}
}
/* 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 bool find_pci_device_prefix(const std::string& path, std::string* result) {
result->clear();
if (!android::base::StartsWith(path, "/devices/pci")) return false;
/* Beginning of the prefix is the initial "pci" after "/devices/" */
std::string::size_type start = 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 */
auto end = path.find('/', start);
if (end == std::string::npos) return false;
end = path.find('/', end + 1);
if (end == std::string::npos) return false;
auto length = end - start;
if (length <= 4) {
// The minimum string that will get to this check is 'pci/', which is malformed,
// so return false
return false;
}
*result = path.substr(start, length);
return true;
}
/* Given a path that may start with a virtual block device, populate
* the supplied buffer with the virtual block device ID and return 0.
* If it doesn't start with a virtual block device, or there is some
* error, return -1 */
static bool find_vbd_device_prefix(const std::string& path, std::string* result) {
result->clear();
if (!android::base::StartsWith(path, "/devices/vbd-")) return false;
/* Beginning of the prefix is the initial "vbd-" after "/devices/" */
std::string::size_type start = 13;
/* End of the prefix is one path '/' later, capturing the
virtual block device ID. Example: 768 */
auto end = path.find('/', start);
if (end == std::string::npos) return false;
auto length = end - start;
if (length == 0) return false;
*result = path.substr(start, length);
return true;
}
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);
}
}
std::vector<std::string> get_character_device_symlinks(uevent* uevent) {
platform_node* pdev = find_platform_device(uevent->path);
if (!pdev) return {};
/* skip "/devices/platform/<driver>" */
std::string parent = std::string(uevent->path);
auto parent_start = parent.find('/', pdev->path_len);
if (parent_start == std::string::npos) return {};
parent.erase(0, parent_start);
if (!android::base::StartsWith(parent, "/usb")) return {};
// skip root hub name and device. use device interface
// skip 3 slashes, including the first / by starting the search at the 1st character, not 0th.
// then extract what comes between the 3rd and 4th slash
// e.g. "/usb/usb_device/name/tty2-1:1.0" -> "name"
std::string::size_type start = 0;
start = parent.find('/', start + 1);
if (start == std::string::npos) return {};
start = parent.find('/', start + 1);
if (start == std::string::npos) return {};
auto end = parent.find('/', start + 1);
if (end == std::string::npos) return {};
start++; // Skip the first '/'
auto length = end - start;
if (length == 0) return {};
auto name_string = parent.substr(start, length);
// TODO: remove std::string() when uevent->subsystem is an std::string
std::vector<std::string> links;
links.emplace_back("/dev/usb/" + std::string(uevent->subsystem) + name_string);
mkdir("/dev/usb", 0755);
return links;
}
// replaces any unacceptable characters with '_', the
// length of the resulting string is equal to the input string
void sanitize_partition_name(std::string* string) {
const char* accept =
"abcdefghijklmnopqrstuvwxyz"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"0123456789"
"_-.";
if (!string) return;
std::string::size_type pos = 0;
while ((pos = string->find_first_not_of(accept, pos)) != std::string::npos) {
(*string)[pos] = '_';
}
}
std::vector<std::string> get_block_device_symlinks(uevent* uevent) {
std::string device;
struct platform_node* pdev;
std::string type;
pdev = find_platform_device(uevent->path);
if (pdev) {
device = pdev->name;
type = "platform";
} else if (find_pci_device_prefix(uevent->path, &device)) {
type = "pci";
} else if (find_vbd_device_prefix(uevent->path, &device)) {
type = "vbd";
} else {
return {};
}
std::vector<std::string> links;
LOG(VERBOSE) << "found " << type << " device " << device;
auto link_path = "/dev/block/" + type + "/" + device;
if (uevent->partition_name) {
std::string partition_name_sanitized(uevent->partition_name);
sanitize_partition_name(&partition_name_sanitized);
if (partition_name_sanitized != uevent->partition_name) {
LOG(VERBOSE) << "Linking partition '" << uevent->partition_name << "' as '"
<< partition_name_sanitized << "'";
}
links.emplace_back(link_path + "/by-name/" + partition_name_sanitized);
}
if (uevent->partition_num >= 0) {
links.emplace_back(link_path + "/by-num/p" + std::to_string(uevent->partition_num));
}
// TODO: remove uevent_path when uevent->path is an std::string
std::string uevent_path = uevent->path;
auto last_slash = uevent_path.rfind('/');
links.emplace_back(link_path + "/" + uevent_path.substr(last_slash + 1));
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, const std::vector<std::string>& links) {
if(!strcmp(action, "add")) {
make_device(devpath, path, block, major, minor, links);
for (const auto& link : links) {
make_link_init(devpath, link.c_str());
}
}
if(!strcmp(action, "remove")) {
for (const auto& link : links) {
remove_link(devpath, link.c_str());
}
unlink(devpath);
}
}
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 void handle_block_device_event(uevent* uevent) {
// if it's not a /dev device, nothing to do
if (uevent->major < 0 || uevent->minor < 0) return;
const char* base = "/dev/block/";
make_dir(base, 0755);
std::string name = android::base::Basename(uevent->path);
std::string devpath = base + name;
std::vector<std::string> links;
if (!strncmp(uevent->path, "/devices/", 9))
links = get_block_device_symlinks(uevent);
handle_device(uevent->action, devpath.c_str(), uevent->path, 1, uevent->major, uevent->minor,
links);
}
static void handle_generic_device_event(uevent* uevent) {
// if it's not a /dev device, nothing to do
if (uevent->major < 0 || uevent->minor < 0) return;
std::string name = android::base::Basename(uevent->path);
ueventd_subsystem* subsystem = ueventd_subsystem_find_by_name(uevent->subsystem);
std::string devpath;
if (subsystem) {
std::string 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;
}
// TODO: Remove std::string()
devpath = std::string(subsystem->dirname) + "/" + devname;
mkdir_recursive(android::base::Dirname(devpath), 0755);
} else if (!strncmp(uevent->subsystem, "usb", 3)) {
if (!strcmp(uevent->subsystem, "usb")) {
if (uevent->device_name) {
// TODO: Remove std::string
devpath = "/dev/" + std::string(uevent->device_name);
} 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;
devpath = android::base::StringPrintf("/dev/bus/usb/%03d/%03d", bus_id, device_id);
}
mkdir_recursive(android::base::Dirname(devpath), 0755);
} else {
// ignore other USB events
return;
}
} else {
devpath = "/dev/" + name;
}
auto links = get_character_device_symlinks(uevent);
handle_device(uevent->action, devpath.c_str(), 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 void load_firmware(uevent* uevent, const std::string& root,
int fw_fd, size_t fw_size,
int loading_fd, int data_fd) {
// Start transfer.
android::base::WriteFully(loading_fd, "1", 1);
// Copy the firmware.
int rc = sendfile(data_fd, fw_fd, nullptr, fw_size);
if (rc == -1) {
PLOG(ERROR) << "firmware: sendfile failed { '" << root << "', '" << uevent->firmware << "' }";
}
// Tell the firmware whether to abort or commit.
const char* response = (rc != -1) ? "0" : "-1";
android::base::WriteFully(loading_fd, response, strlen(response));
}
static int is_booting() {
return access("/dev/.booting", F_OK) == 0;
}
static void process_firmware_event(uevent* uevent) {
int booting = is_booting();
LOG(INFO) << "firmware: loading '" << uevent->firmware << "' for '" << uevent->path << "'";
std::string root = android::base::StringPrintf("/sys%s", uevent->path);
std::string loading = root + "/loading";
std::string data = root + "/data";
android::base::unique_fd loading_fd(open(loading.c_str(), O_WRONLY|O_CLOEXEC));
if (loading_fd == -1) {
PLOG(ERROR) << "couldn't open firmware loading fd for " << uevent->firmware;
return;
}
android::base::unique_fd data_fd(open(data.c_str(), O_WRONLY|O_CLOEXEC));
if (data_fd == -1) {
PLOG(ERROR) << "couldn't open firmware data fd for " << uevent->firmware;
return;
}
try_loading_again:
for (size_t i = 0; i < arraysize(firmware_dirs); i++) {
std::string file = android::base::StringPrintf("%s/%s", firmware_dirs[i], uevent->firmware);
android::base::unique_fd fw_fd(open(file.c_str(), O_RDONLY|O_CLOEXEC));
struct stat sb;
if (fw_fd != -1 && fstat(fw_fd, &sb) != -1) {
load_firmware(uevent, root, fw_fd, sb.st_size, loading_fd, data_fd);
return;
}
}
if (booting) {
// If we're not fully booted, we may be missing
// filesystems needed for firmware, wait and retry.
std::this_thread::sleep_for(100ms);
booting = is_booting();
goto try_loading_again;
}
LOG(ERROR) << "firmware: could not find firmware for " << uevent->firmware;
// Write "-1" as our response to the kernel's firmware request, since we have nothing for it.
write(loading_fd, "-1", 2);
}
static void handle_firmware_event(uevent* uevent) {
if (strcmp(uevent->subsystem, "firmware")) return;
if (strcmp(uevent->action, "add")) return;
// Loading the firmware in a child means we can do that in parallel...
// (We ignore SIGCHLD rather than wait for our children.)
pid_t pid = fork();
if (pid == 0) {
Timer t;
process_firmware_event(uevent);
LOG(INFO) << "loading " << uevent->path << " took " << t;
_exit(EXIT_SUCCESS);
} else if (pid == -1) {
PLOG(ERROR) << "could not fork to process firmware event for " << uevent->firmware;
}
}
static bool inline should_stop_coldboot(coldboot_action_t act)
{
return (act == COLDBOOT_STOP || act == COLDBOOT_FINISH);
}
#define UEVENT_MSG_LEN 2048
static inline coldboot_action_t handle_device_fd_with(
std::function<coldboot_action_t(uevent* uevent)> handle_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);
coldboot_action_t act = handle_uevent(&uevent);
if (should_stop_coldboot(act))
return act;
}
return COLDBOOT_CONTINUE;
}
coldboot_action_t handle_device_fd(coldboot_callback fn)
{
coldboot_action_t ret = handle_device_fd_with(
[&](uevent* uevent) -> coldboot_action_t {
if (selinux_status_updated() > 0) {
struct selabel_handle *sehandle2;
sehandle2 = selinux_android_file_context_handle();
if (sehandle2) {
selabel_close(sehandle);
sehandle = sehandle2;
}
}
// default is to always create the devices
coldboot_action_t act = COLDBOOT_CREATE;
if (fn) {
act = fn(uevent);
}
if (act == COLDBOOT_CREATE || act == COLDBOOT_STOP) {
handle_device_event(uevent);
handle_firmware_event(uevent);
}
return act;
});
return ret;
}
/* 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 coldboot_action_t do_coldboot(DIR *d, coldboot_callback fn)
{
struct dirent *de;
int dfd, fd;
coldboot_action_t act = COLDBOOT_CONTINUE;
dfd = dirfd(d);
fd = openat(dfd, "uevent", O_WRONLY);
if (fd >= 0) {
write(fd, "add\n", 4);
close(fd);
act = handle_device_fd(fn);
if (should_stop_coldboot(act))
return act;
}
while (!should_stop_coldboot(act) && (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 {
act = do_coldboot(d2, fn);
closedir(d2);
}
}
// default is always to continue looking for uevents
return act;
}
static coldboot_action_t coldboot(const char *path, coldboot_callback fn)
{
std::unique_ptr<DIR, decltype(&closedir)> d(opendir(path), closedir);
if (d) {
return do_coldboot(d.get(), fn);
}
return COLDBOOT_CONTINUE;
}
void device_init(const char* path, coldboot_callback fn) {
if (!sehandle) {
sehandle = selinux_android_file_context_handle();
}
// open uevent socket and selinux status only if it hasn't been
// done before
if (device_fd == -1) {
/* is 256K enough? udev uses 16MB! */
device_fd.reset(uevent_open_socket(256 * 1024, true));
if (device_fd == -1) {
return;
}
fcntl(device_fd, F_SETFL, O_NONBLOCK);
selinux_status_open(true);
}
if (access(COLDBOOT_DONE, F_OK) == 0) {
LOG(VERBOSE) << "Skipping coldboot, already done!";
return;
}
Timer t;
coldboot_action_t act;
if (!path) {
act = coldboot("/sys/class", fn);
if (!should_stop_coldboot(act)) {
act = coldboot("/sys/block", fn);
if (!should_stop_coldboot(act)) {
act = coldboot("/sys/devices", fn);
}
}
} else {
act = coldboot(path, fn);
}
// If we have a callback, then do as it says. If no, then the default is
// to always create COLDBOOT_DONE file.
if (!fn || (act == COLDBOOT_FINISH)) {
close(open(COLDBOOT_DONE, O_WRONLY|O_CREAT|O_CLOEXEC, 0000));
}
LOG(INFO) << "Coldboot took " << t;
}
void device_close() {
destroy_platform_devices();
device_fd.reset();
selinux_status_close();
}
int get_device_fd() {
return device_fd;
}
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