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platform_system_core/init/devices.cpp
Elliott Hughes 51056c49d2 init should #include <sys/sysmacros.h> 
Bug: https://github.com/android-ndk/ndk/issues/398
Test: builds
Change-Id: I6428a6344a3ce649bd03ff9e9b0f156425c67f0c
2017-05-18 09:13:15 -07:00

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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 "devices.h"
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <fnmatch.h>
#include <grp.h>
#include <libgen.h>
#include <linux/netlink.h>
#include <pwd.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/sendfile.h>
#include <sys/socket.h>
#include <sys/sysmacros.h>
#include <sys/time.h>
#include <sys/un.h>
#include <sys/wait.h>
#include <unistd.h>
#include <algorithm>
#include <memory>
#include <thread>
#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/uevent.h>
#include <private/android_filesystem_config.h>
#include <selinux/android.h>
#include <selinux/label.h>
#include <selinux/selinux.h>
#include "keyword_map.h"
#include "ueventd.h"
#include "util.h"
#ifdef _INIT_INIT_H
#error "Do not include init.h in files used by ueventd or watchdogd; it will expose init's globals"
#endif
static selabel_handle* sehandle;
static android::base::unique_fd device_fd;
Permissions::Permissions(const std::string& name, mode_t perm, uid_t uid, gid_t gid)
: name_(name), perm_(perm), uid_(uid), gid_(gid), prefix_(false), wildcard_(false) {
// If the first * is the last character, then we'll treat name_ as a prefix
// Otherwise, if a * is present, then we do a full fnmatch().
auto wildcard_position = name_.find('*');
if (wildcard_position == name_.length() - 1) {
prefix_ = true;
name_.pop_back();
} else if (wildcard_position != std::string::npos) {
wildcard_ = true;
}
}
bool Permissions::Match(const std::string& path) const {
if (prefix_) {
return android::base::StartsWith(path, name_.c_str());
} else if (wildcard_) {
return fnmatch(name_.c_str(), path.c_str(), FNM_PATHNAME) == 0;
} else {
return path == name_;
}
return false;
}
bool SysfsPermissions::MatchWithSubsystem(const std::string& path,
const std::string& subsystem) const {
std::string path_basename = android::base::Basename(path);
if (name().find(subsystem) != std::string::npos) {
if (Match("/sys/class/" + subsystem + "/" + path_basename)) return true;
if (Match("/sys/bus/" + subsystem + "/devices/" + path_basename)) return true;
}
return Match(path);
}
void SysfsPermissions::SetPermissions(const std::string& path) const {
std::string attribute_file = path + "/" + attribute_;
LOG(INFO) << "fixup " << attribute_file << " " << uid() << " " << gid() << " " << std::oct
<< perm();
chown(attribute_file.c_str(), uid(), gid());
chmod(attribute_file.c_str(), perm());
}
// TODO: Move these to be member variables of a future devices class.
std::vector<Permissions> dev_permissions;
std::vector<SysfsPermissions> sysfs_permissions;
bool ParsePermissionsLine(std::vector<std::string>&& args, std::string* err, bool is_sysfs) {
if (is_sysfs && args.size() != 5) {
*err = "/sys/ lines must have 5 entries";
return false;
}
if (!is_sysfs && args.size() != 4) {
*err = "/dev/ lines must have 4 entries";
return false;
}
auto it = args.begin();
const std::string& name = *it++;
std::string sysfs_attribute;
if (is_sysfs) sysfs_attribute = *it++;
// args is now common to both sys and dev entries and contains: <perm> <uid> <gid>
std::string& perm_string = *it++;
char* end_pointer = 0;
mode_t perm = strtol(perm_string.c_str(), &end_pointer, 8);
if (end_pointer == nullptr || *end_pointer != '\0') {
*err = "invalid mode '" + perm_string + "'";
return false;
}
std::string& uid_string = *it++;
passwd* pwd = getpwnam(uid_string.c_str());
if (!pwd) {
*err = "invalid uid '" + uid_string + "'";
return false;
}
uid_t uid = pwd->pw_uid;
std::string& gid_string = *it++;
struct group* grp = getgrnam(gid_string.c_str());
if (!grp) {
*err = "invalid gid '" + gid_string + "'";
return false;
}
gid_t gid = grp->gr_gid;
if (is_sysfs) {
sysfs_permissions.emplace_back(name, sysfs_attribute, perm, uid, gid);
} else {
dev_permissions.emplace_back(name, perm, uid, gid);
}
return true;
}
// TODO: Move this to be a member variable of a future devices class.
static std::vector<Subsystem> subsystems;
std::string Subsystem::ParseDevPath(uevent* uevent) const {
std::string devname = devname_source_ == DevnameSource::DEVNAME_UEVENT_DEVNAME
? uevent->device_name
: android::base::Basename(uevent->path);
return dir_name_ + "/" + devname;
}
bool SubsystemParser::ParseSection(std::vector<std::string>&& args, const std::string& filename,
int line, std::string* err) {
if (args.size() != 2) {
*err = "subsystems must have exactly one name";
return false;
}
if (std::find(subsystems.begin(), subsystems.end(), args[1]) != subsystems.end()) {
*err = "ignoring duplicate subsystem entry";
return false;
}
subsystem_.name_ = args[1];
return true;
}
bool SubsystemParser::ParseDevName(std::vector<std::string>&& args, std::string* err) {
if (args[1] == "uevent_devname") {
subsystem_.devname_source_ = Subsystem::DevnameSource::DEVNAME_UEVENT_DEVNAME;
return true;
}
if (args[1] == "uevent_devpath") {
subsystem_.devname_source_ = Subsystem::DevnameSource::DEVNAME_UEVENT_DEVPATH;
return true;
}
*err = "invalid devname '" + args[1] + "'";
return false;
}
bool SubsystemParser::ParseDirName(std::vector<std::string>&& args, std::string* err) {
if (args[1].front() != '/') {
*err = "dirname '" + args[1] + " ' does not start with '/'";
return false;
}
subsystem_.dir_name_ = args[1];
return true;
}
bool SubsystemParser::ParseLineSection(std::vector<std::string>&& args, int line, std::string* err) {
using OptionParser =
bool (SubsystemParser::*)(std::vector<std::string> && args, std::string * err);
static class OptionParserMap : public KeywordMap<OptionParser> {
private:
const Map& map() const override {
// clang-format off
static const Map option_parsers = {
{"devname", {1, 1, &SubsystemParser::ParseDevName}},
{"dirname", {1, 1, &SubsystemParser::ParseDirName}},
};
// clang-format on
return option_parsers;
}
} parser_map;
auto parser = parser_map.FindFunction(args, err);
if (!parser) {
return false;
}
return (this->*parser)(std::move(args), err);
}
void SubsystemParser::EndSection() {
subsystems.emplace_back(std::move(subsystem_));
}
static void fixup_sys_permissions(const std::string& upath, const std::string& subsystem) {
// upaths omit the "/sys" that paths in this list
// contain, so we prepend it...
std::string path = "/sys" + upath;
for (const auto& s : sysfs_permissions) {
if (s.MatchWithSubsystem(path, subsystem)) s.SetPermissions(path);
}
if (access(path.c_str(), F_OK) == 0) {
LOG(VERBOSE) << "restorecon_recursive: " << path;
selinux_android_restorecon(path.c_str(), SELINUX_ANDROID_RESTORECON_RECURSE);
}
}
static std::tuple<mode_t, uid_t, gid_t> get_device_permissions(
const std::string& path, const std::vector<std::string>& links) {
// Search the perms list in reverse so that ueventd.$hardware can override ueventd.rc.
for (auto it = dev_permissions.rbegin(); it != dev_permissions.rend(); ++it) {
if (it->Match(path) || std::any_of(links.begin(), links.end(),
[it](const auto& link) { return it->Match(link); })) {
return {it->perm(), it->uid(), it->gid()};
}
}
/* Default if nothing found. */
return {0600, 0, 0};
}
static void make_device(const std::string& path, int block, int major, int minor,
const std::vector<std::string>& links) {
dev_t dev;
char *secontext = NULL;
auto [mode, uid, gid] = get_device_permissions(path, links);
mode |= (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_str(), &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.c_str(), mode, dev) && (errno == EEXIST) && secontext) {
char* fcon = nullptr;
int rc = lgetfilecon(path.c_str(), &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.c_str(), secontext)) {
PLOG(ERROR) << "Cannot set '" << secontext << "' SELinux label on '" << path << "' device";
}
}
out:
chown(path.c_str(), uid, -1);
if (setegid(AID_ROOT)) {
PLOG(FATAL) << "setegid(AID_ROOT) failed";
}
if (secontext) {
freecon(secontext);
setfscreatecon(NULL);
}
}
// TODO: Move this to be a member variable of a future devices class.
std::vector<std::string> platform_devices;
// 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 false
bool find_platform_device(const std::string& path, std::string* out_path) {
out_path->clear();
// platform_devices is searched backwards, since parents are added before their children,
// and we want to match as deep of a child as we can.
for (auto it = platform_devices.rbegin(); it != platform_devices.rend(); ++it) {
auto platform_device_path_length = it->length();
if (platform_device_path_length < path.length() &&
path[platform_device_path_length] == '/' &&
android::base::StartsWith(path, it->c_str())) {
*out_path = *it;
return true;
}
}
return false;
}
/* 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;
}
void parse_event(const char* msg, uevent* uevent) {
uevent->partition_num = -1;
uevent->major = -1;
uevent->minor = -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;
} 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) << "event { '" << uevent->action << "', '" << uevent->path << "', '"
<< uevent->subsystem << "', '" << uevent->firmware << "', " << uevent->major
<< ", " << uevent->minor << " }";
}
}
std::vector<std::string> get_character_device_symlinks(uevent* uevent) {
std::string parent_device;
if (!find_platform_device(uevent->path, &parent_device)) return {};
// skip path to the parent driver
std::string path = uevent->path.substr(parent_device.length());
if (!android::base::StartsWith(path, "/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 = path.find('/', start + 1);
if (start == std::string::npos) return {};
start = path.find('/', start + 1);
if (start == std::string::npos) return {};
auto end = path.find('/', start + 1);
if (end == std::string::npos) return {};
start++; // Skip the first '/'
auto length = end - start;
if (length == 0) return {};
auto name_string = path.substr(start, length);
std::vector<std::string> links;
links.emplace_back("/dev/usb/" + 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;
std::string type;
if (find_platform_device(uevent->path, &device)) {
// Skip /devices/platform or /devices/ if present
static const std::string devices_platform_prefix = "/devices/platform/";
static const std::string devices_prefix = "/devices/";
if (android::base::StartsWith(device, devices_platform_prefix.c_str())) {
device = device.substr(devices_platform_prefix.length());
} else if (android::base::StartsWith(device, devices_prefix.c_str())) {
device = device.substr(devices_prefix.length());
}
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.empty()) {
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));
}
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 std::string& oldpath, const std::string& newpath) {
if (mkdir_recursive(dirname(newpath.c_str()), 0755, sehandle)) {
PLOG(ERROR) << "Failed to create directory " << dirname(newpath.c_str());
}
if (symlink(oldpath.c_str(), newpath.c_str()) && errno != EEXIST) {
PLOG(ERROR) << "Failed to symlink " << oldpath << " to " << newpath;
}
}
static void remove_link(const std::string& oldpath, const std::string& newpath) {
std::string path;
if (android::base::Readlink(newpath, &path) && path == oldpath) unlink(newpath.c_str());
}
static void handle_device(const std::string& action, const std::string& devpath, int block,
int major, int minor, const std::vector<std::string>& links) {
if (action == "add") {
make_device(devpath, block, major, minor, links);
for (const auto& link : links) {
make_link_init(devpath, link);
}
}
if (action == "remove") {
for (const auto& link : links) {
remove_link(devpath, link);
}
unlink(devpath.c_str());
}
}
void handle_platform_device_event(uevent* uevent) {
if (uevent->action == "add") {
platform_devices.emplace_back(uevent->path);
} else if (uevent->action == "remove") {
auto it = std::find(platform_devices.begin(), platform_devices.end(), uevent->path);
if (it != platform_devices.end()) platform_devices.erase(it);
}
}
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, sehandle);
std::string name = android::base::Basename(uevent->path);
std::string devpath = base + name;
std::vector<std::string> links;
if (android::base::StartsWith(uevent->path, "/devices")) {
links = get_block_device_symlinks(uevent);
}
handle_device(uevent->action, devpath, 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 devpath;
if (android::base::StartsWith(uevent->subsystem, "usb")) {
if (uevent->subsystem == "usb") {
if (!uevent->device_name.empty()) {
devpath = "/dev/" + 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);
}
} else {
// ignore other USB events
return;
}
} else if (auto subsystem = std::find(subsystems.begin(), subsystems.end(), uevent->subsystem);
subsystem != subsystems.end()) {
devpath = subsystem->ParseDevPath(uevent);
} else {
devpath = "/dev/" + android::base::Basename(uevent->path);
}
mkdir_recursive(android::base::Dirname(devpath), 0755, sehandle);
auto links = get_character_device_symlinks(uevent);
handle_device(uevent->action, devpath, 0, uevent->major, uevent->minor, links);
}
static void handle_device_event(struct uevent *uevent)
{
if (uevent->action == "add" || uevent->action == "change" || uevent->action == "online") {
fixup_sys_permissions(uevent->path, uevent->subsystem);
}
if (uevent->subsystem == "block") {
handle_block_device_event(uevent);
} else if (uevent->subsystem == "platform") {
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 = "/sys" + 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;
}
static const char* firmware_dirs[] = {"/etc/firmware/", "/vendor/firmware/",
"/firmware/image/"};
try_loading_again:
for (size_t i = 0; i < arraysize(firmware_dirs); i++) {
std::string file = 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 (uevent->subsystem != "firmware" || 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';
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 {
// 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);
}
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() {
platform_devices.clear();
device_fd.reset();
}
int get_device_fd() {
return device_fd;
}
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