Init: add dev.mnt.blk.bootdevice to access device sysfs
This patch adds a new property, 'dev.mnt.root.<mount_point>', which provides,
for example of /data,
1. dm-N
dev.mnt.dev.data = dm-N
dev.mnt.blk.data = sdaN or mmcblk0pN
dev.mnt.rootdisk.data = sda or mmcblk0
2. sdaN or mmcblk0pN
dev.mnt.dev.data = sdaN or mmcblk0pN
dev.mnt.blk.data = sdaN or mmcblk0pN
dev.mnt.rootdisk.data = sda or mmcblk0
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>
Change-Id: I0a58a62d416f966f26b5de04112c2f9a7eceb22c
diff --git a/init/README.md b/init/README.md
index c82dbfb..13c6ebd 100644
--- a/init/README.md
+++ b/init/README.md
@@ -804,13 +804,18 @@
`init.svc.<name>`
> State of a named service ("stopped", "stopping", "running", "restarting")
-`dev.mnt.blk.<mount_point>`
+`dev.mnt.dev.<mount_point>`, `dev.mnt.blk.<mount_point>`, `dev.mnt.rootdisk.<mount_point>`
> Block device base name associated with a *mount_point*.
The *mount_point* has / replaced by . and if referencing the root mount point
- "/", it will use "/root", specifically `dev.mnt.blk.root`.
- Meant for references to `/sys/device/block/${dev.mnt.blk.<mount_point>}/` and
- `/sys/fs/ext4/${dev.mnt.blk.<mount_point>}/` to tune the block device
- characteristics in a device agnostic manner.
+ "/", it will use "/root".
+ `dev.mnt.dev.<mount_point>` indicates a block device attached to filesystems.
+ (e.g., dm-N or sdaN/mmcblk0pN to access `/sys/fs/ext4/${dev.mnt.dev.<mount_point>}/`)
+
+ `dev.mnt.blk.<mount_point>` indicates the disk partition to the above block device.
+ (e.g., sdaN / mmcblk0pN to access `/sys/class/block/${dev.mnt.blk.<mount_point>}/`)
+
+ `dev.mnt.rootdisk.<mount_point>` indicates the root disk to contain the above disk partition.
+ (e.g., sda / mmcblk0 to access `/sys/class/block/${dev.mnt.rootdisk.<mount_point>}/queue`)
Init responds to properties that begin with `ctl.`. These properties take the format of
`ctl.[<target>_]<command>` and the _value_ of the system property is used as a parameter. The
diff --git a/init/mount_handler.cpp b/init/mount_handler.cpp
index 15ac305..227ce2f 100644
--- a/init/mount_handler.cpp
+++ b/init/mount_handler.cpp
@@ -72,8 +72,25 @@
return MountHandlerEntry(fields[0], fields[1], fields[2]);
}
-// return dm-4 or dm-8 for dm-4, sda for sda25, or mmcblk0 for mmcblk0p24
+// return sda25 for dm-4, sda25 for sda25, or mmcblk0p24 for mmcblk0p24
+std::string GetDiskPart(std::string blockdev) {
+ if (blockdev.find('/') != std::string::npos) return {};
+
+ while (android::base::StartsWith(blockdev, "dm-")) {
+ auto& dm = dm::DeviceMapper::Instance();
+ std::optional<std::string> parent = dm.GetParentBlockDeviceByPath("/dev/block/" + blockdev);
+ if (parent) {
+ blockdev = android::base::Basename(*parent);
+ } else {
+ return {};
+ }
+ }
+ return blockdev;
+}
+
+// return sda for sda25, or mmcblk0 for mmcblk0p24
std::string GetRootDisk(std::string blockdev) {
+ if (blockdev.empty()) return {};
if (blockdev.find('/') != std::string::npos) return {};
std::error_code ec;
@@ -83,7 +100,6 @@
return Basename(path);
}
}
- if (android::base::StartsWith(blockdev, "dm-")) return blockdev;
return {};
}
@@ -91,31 +107,47 @@
static constexpr char devblock[] = "/dev/block/";
if (!android::base::StartsWith(entry.blk_device, devblock)) return;
auto target = entry.blk_device.substr(strlen(devblock));
- std::string value;
+ std::string diskpart, rootdisk;
if (add) {
- value = GetRootDisk(target);
+ diskpart = GetDiskPart(target);
+ rootdisk = GetRootDisk(diskpart);
struct stat sb;
- if (stat(entry.mount_point.c_str(), &sb) || !S_ISDIR(sb.st_mode)) value = "";
+ if (stat(entry.mount_point.c_str(), &sb) || !S_ISDIR(sb.st_mode)) rootdisk = "";
// Clear the noise associated with loopback and APEX.
- if (android::base::StartsWith(value, "loop")) value = "";
- if (android::base::StartsWith(entry.mount_point, "/apex/")) value = "";
+ if (android::base::StartsWith(target, "loop")) rootdisk = "";
+ if (android::base::StartsWith(entry.mount_point, "/apex/")) rootdisk = "";
}
auto mount_prop = entry.mount_point;
if (mount_prop == "/") mount_prop = "/root";
std::replace(mount_prop.begin(), mount_prop.end(), '/', '.');
auto blk_mount_prop = "dev.mnt.blk" + mount_prop;
auto dev_mount_prop = "dev.mnt.dev" + mount_prop;
- // Set property even if its value does not change to trigger 'on property:'
+ auto rootdisk_mount_prop = "dev.mnt.rootdisk" + mount_prop;
+ // Set property even if its rootdisk does not change to trigger 'on property:'
// handling, except for clearing non-existent or already clear property.
// Goal is reduction of empty properties and associated triggers.
- if (value.empty() && android::base::GetProperty(blk_mount_prop, "").empty()) return;
- android::base::SetProperty(blk_mount_prop, value);
- if (!value.empty()) {
- android::base::SetProperty(dev_mount_prop, target);
- } else {
+ if (rootdisk.empty() && android::base::GetProperty(blk_mount_prop, "").empty()) return;
+
+ if (rootdisk.empty()) {
+ android::base::SetProperty(blk_mount_prop, "");
android::base::SetProperty(dev_mount_prop, "");
+ android::base::SetProperty(rootdisk_mount_prop, "");
+ return;
}
+
+ // 1. dm-N
+ // dev.mnt.dev.data = dm-N
+ // dev.mnt.blk.data = sdaN or mmcblk0pN
+ // dev.mnt.rootdisk.data = sda or mmcblk0
+ //
+ // 2. sdaN or mmcblk0pN
+ // dev.mnt.dev.data = sdaN or mmcblk0pN
+ // dev.mnt.blk.data = sdaN or mmcblk0pN
+ // dev.mnt.rootdisk.data = sda or mmcblk0
+ android::base::SetProperty(dev_mount_prop, target);
+ android::base::SetProperty(blk_mount_prop, diskpart);
+ android::base::SetProperty(rootdisk_mount_prop, rootdisk);
}
} // namespace