ueventd: add support for driver section in ueventd.rc
Allow ueventd configuration to specify what to do with
devices based on driver. This responds to bind events and
treats them similarly to add events.
The format of the driver stanza is exactly the same as
that of the subsystem stanza.
Bug: 376900376
Test: set up cbc_mbim driver stanza and ensure it properly
creates and destroys device nodes when a USB device with
that driver appears and disappears or is bound and unbound
Change-Id: I31f5c91bd074d14075b74fe7beefaa6ac07a7ac9
diff --git a/init/devices.cpp b/init/devices.cpp
index fafa58f..aeaa431 100644
--- a/init/devices.cpp
+++ b/init/devices.cpp
@@ -345,6 +345,26 @@
return FindSubsystemDevice(path, scsi_device_path, subsystem_paths);
}
+void DeviceHandler::TrackDeviceUevent(const Uevent& uevent) {
+ // No need to track any events if we won't bother handling any bind events
+ // later.
+ if (drivers_.size() == 0) return;
+
+ // Only track add, and not for block devices. We don't track remove because
+ // unbind events may arrive after remove events, so unbind will be the
+ // trigger to untrack those events.
+ if ((uevent.action != "add") || uevent.subsystem == "block" ||
+ (uevent.major < 0 || uevent.minor < 0)) {
+ return;
+ }
+
+ std::string path = sysfs_mount_point_ + uevent.path + "/device";
+ std::string device;
+ if (!Realpath(path, &device)) return;
+
+ tracked_uevents_.emplace_back(uevent, device);
+}
+
void DeviceHandler::FixupSysPermissions(const std::string& upath,
const std::string& subsystem) const {
// upaths omit the "/sys" that paths in this list
@@ -664,12 +684,53 @@
return true;
}
+void DeviceHandler::HandleBindInternal(std::string driver_name, std::string action,
+ const Uevent& uevent) {
+ if (uevent.subsystem == "block") {
+ LOG(FATAL) << "Tried to handle bind event for block device";
+ }
+
+ // Get tracked uevents for all devices that have this uevent's path as
+ // their canonical device path. Then handle those again if their driver
+ // is one of the ones we're interested in.
+ const auto driver = std::find(drivers_.cbegin(), drivers_.cend(), driver_name);
+ if (driver == drivers_.cend()) return;
+
+ std::string bind_path = sysfs_mount_point_ + uevent.path;
+ for (const TrackedUevent& tracked : tracked_uevents_) {
+ if (tracked.canonical_device_path != bind_path) continue;
+
+ LOG(VERBOSE) << "Propagating " << uevent.action << " as " << action << " for "
+ << uevent.path;
+
+ std::string devpath = driver->ParseDevPath(tracked.uevent);
+ mkdir_recursive(Dirname(devpath), 0755);
+ HandleDevice(action, devpath, false, tracked.uevent.major, tracked.uevent.minor,
+ std::vector<std::string>{});
+ }
+}
+
void DeviceHandler::HandleUevent(const Uevent& uevent) {
if (uevent.action == "add" || uevent.action == "change" || uevent.action == "bind" ||
uevent.action == "online") {
FixupSysPermissions(uevent.path, uevent.subsystem);
}
+ if (uevent.action == "bind") {
+ bound_drivers_[uevent.path] = uevent.driver;
+ HandleBindInternal(uevent.driver, "add", uevent);
+ return;
+ } else if (uevent.action == "unbind") {
+ if (bound_drivers_.count(uevent.path) == 0) return;
+ HandleBindInternal(bound_drivers_[uevent.path], "remove", uevent);
+
+ std::string sys_path = sysfs_mount_point_ + uevent.path;
+ std::erase_if(tracked_uevents_, [&sys_path](const TrackedUevent& tracked) {
+ return sys_path == tracked.canonical_device_path;
+ });
+ return;
+ }
+
// if it's not a /dev device, nothing to do
if (uevent.major < 0 || uevent.minor < 0) return;
@@ -677,6 +738,8 @@
std::vector<std::string> links;
bool block = false;
+ TrackDeviceUevent(uevent);
+
if (uevent.subsystem == "block") {
block = true;
devpath = "/dev/block/" + Basename(uevent.path);
@@ -725,10 +788,12 @@
DeviceHandler::DeviceHandler(std::vector<Permissions> dev_permissions,
std::vector<SysfsPermissions> sysfs_permissions,
- std::vector<Subsystem> subsystems, std::set<std::string> boot_devices,
- std::string boot_part_uuid, bool skip_restorecon)
+ std::vector<Subsystem> drivers, std::vector<Subsystem> subsystems,
+ std::set<std::string> boot_devices, std::string boot_part_uuid,
+ bool skip_restorecon)
: dev_permissions_(std::move(dev_permissions)),
sysfs_permissions_(std::move(sysfs_permissions)),
+ drivers_(std::move(drivers)),
subsystems_(std::move(subsystems)),
boot_devices_(std::move(boot_devices)),
boot_part_uuid_(boot_part_uuid),
@@ -744,7 +809,8 @@
DeviceHandler::DeviceHandler()
: DeviceHandler(std::vector<Permissions>{}, std::vector<SysfsPermissions>{},
- std::vector<Subsystem>{}, std::set<std::string>{}, "", false) {}
+ std::vector<Subsystem>{}, std::vector<Subsystem>{}, std::set<std::string>{}, "",
+ false) {}
} // namespace init
} // namespace android