uvol: replace with re-write in ucode

Replace previous Shell draft-quality implementation of uvol with a
rewrite in ucode[1].
While the new code is slightly larger, it performs much better (as
we no longer fork() for parsing strings like in Shell with grep, sed
and friends).

Before:
  time uvol list -j
  [ ... ]
  real	0m 0.82s
  user	0m 0.13s
  sys	0m 0.10s

After:
  time uvol list -j
  [ ... ]
  real	0m 0.47s
  user	0m 0.05s
  sys	0m 0.05s

[1]: https://github.com/jow-/ucode
Signed-off-by: Daniel Golle <[email protected]>

utils/uvol/Makefile

@@ -1,7 +1,7 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=uvol
-PKG_VERSION:=0.6
+PKG_VERSION:=0.7
 PKG_RELEASE:=$(AUTORELEASE)
 
 PKG_MAINTAINER:=Daniel Golle <[email protected]>
@@ -19,27 +19,30 @@ define Package/autopart
 endef
 
 define Package/autopart/description
- Automatically allocate the GPT partition for LVM and initialize it
- on first boot.
+ Automatically allocate and initialize a partition for LVM on first boot.
 endef
 
 define Package/uvol
   SECTION:=utils
   CATEGORY:=Utilities
   SUBMENU:=Disc
   TITLE:=OpenWrt UBI/LVM volume abstraction
-  DEPENDS:=+blockd
+  DEPENDS:=+blockd +ucode +ucode-mod-fs +ucode-mod-uci
   PKGARCH=all
 endef
 
 define Package/uvol/description
   'uvol' is tool to automate storage volume handling on embedded
   devices in a generic way.
+  Depending on what is available, 'uvol' will use either UBI or LVM2
+  as storage backends and transparently offer identical operations on
+  top of them.
+
   Also install the 'autopart' package to easily make use of 'uvol' on
   block-storage based devices.
 
   Examples:
-  uvol create example_volume_1 256MiB rw
+  uvol create example_volume_1 268435456 rw
   uvol up example_volume_1
   uvol device example_volume_1
 
@@ -64,11 +67,12 @@ define Package/autopart/install
 endef
 
 define Package/uvol/install
-	$(INSTALL_DIR) $(1)/etc/init.d $(1)/usr/libexec/uvol $(1)/usr/sbin $(1)/lib/functions $(1)/etc/uci-defaults
+	$(INSTALL_DIR) $(1)/etc/init.d $(1)/usr/uvol/backends $(1)/usr/sbin $(1)/etc/uci-defaults
 	$(INSTALL_BIN) ./files/uvol.init $(1)/etc/init.d/uvol
-	$(INSTALL_BIN) ./files/common.sh $(1)/lib/functions/uvol.sh
-	$(INSTALL_BIN) ./files/ubi.sh $(1)/usr/libexec/uvol/20-ubi.sh
-	$(INSTALL_BIN) ./files/lvm.sh $(1)/usr/libexec/uvol/50-lvm.sh
+	$(INSTALL_DATA) ./files/blockdev_common.uc $(1)/usr/lib/uvol/
+	$(INSTALL_DATA) ./files/uci.uc $(1)/usr/lib/uvol/
+	$(INSTALL_DATA) ./files/lvm.uc $(1)/usr/lib/uvol/backends/
+	$(INSTALL_DATA) ./files/ubi.uc $(1)/usr/lib/uvol/backends/
 	$(INSTALL_BIN) ./files/uvol $(1)/usr/sbin
 	$(INSTALL_BIN) ./files/uvol.defaults $(1)/etc/uci-defaults/90-uvol-init
 endef

utils/uvol/files/blockdev_common.uc

@@ -0,0 +1,123 @@
+{%
+// SPDX-License-Identifier: GPL-2.0-or-later
+// Helper functions used to identify the boot device
+	// adapted from /lib/functions.sh
+	let cmdline_get_var = function(var) {
+		let cmdline = fs.open("/proc/cmdline", "r");
+		let allargs = cmdline.read("all");
+		cmdline.close();
+		let ret = null;
+		for (let arg in split(allargs, /[ \t\n]/)) {
+			let el = split(arg, "=");
+			if (shift(el) == var)
+				return join("=", el);
+		}
+		return ret;
+	};
+
+	// adapted from /lib/upgrade/common.sh
+	let get_blockdevs = function() {
+		let devs = [];
+		for (let dev in fs.glob('/dev/*'))
+			if (fs.stat(dev).type == "block")
+				push(devs, split(dev, '/')[-1]);
+
+		return devs;
+	};
+
+	// adapted from /lib/upgrade/common.sh
+	let get_uevent_major_minor = function(file) {
+		let uevf = fs.open(file, "r");
+		if (!uevf)
+			return null;
+
+		let r = {};
+		let evl;
+		while ((evl = uevf.read("line"))) {
+		let ev = split(evl, '=');
+			if (ev[0] == "MAJOR")
+				r.major = +ev[1];
+			if (ev[0] == "MINOR")
+				r.minor = +ev[1];
+		}
+		uevf.close();
+		return r;
+	};
+
+	// adapted from /lib/upgrade/common.sh
+	let get_bootdev = function(void) {
+		let rootpart = cmdline_get_var("root");
+		let uevent = null;
+
+		if (wildcard(rootpart, "PARTUUID=[a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9]-[a-f0-9][a-f0-9]")) {
+			let uuidarg = split(substr(rootpart, 9), '-')[0];
+			for (let bd in get_blockdevs()) {
+				let bdf = fs.open(sprintf("/dev/%s", bd), "r");
+				bdf.seek(440);
+				let bduuid = bdf.read(4);
+				bdf.close();
+				if (uuidarg == sprintf("%x%x%x%x", ord(bduuid, 3), ord(bduuid, 2), ord(bduuid, 1), ord(bduuid, 0))) {
+					uevent = sprintf("/sys/class/block/%s/uevent", bd);
+					break;
+				}
+			}
+		} else if (wildcard(rootpart, "PARTUUID=????????-????-????-????-??????????0?/PARTNROFF=*") ||
+			   wildcard(rootpart, "PARTUUID=????????-????-????-????-??????????02")) {
+			let uuidarg = substr(split(substr(rootpart, 9), '/')[0], 0, -2) + "00";
+			for (let bd in get_blockdevs()) {
+				let bdf = fs.open(sprintf("/dev/%s", bd), "r");
+				bdf.seek(568);
+				let bduuid = bdf.read(16);
+				bdf.close();
+				if (!bduuid)
+					continue;
+
+				let uuid = sprintf("%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
+					ord(bduuid, 3), ord(bduuid, 2), ord(bduuid, 1), ord(bduuid, 0),
+					ord(bduuid, 5), ord(bduuid, 4),
+					ord(bduuid, 7), ord(bduuid, 6),
+					ord(bduuid, 8), ord(bduuid, 9),
+					ord(bduuid, 10), ord(bduuid, 11), ord(bduuid, 12), ord(bduuid, 13), ord(bduuid, 14), ord(bduuid, 15));
+				if (uuidarg == uuid) {
+					uevent = sprintf("/sys/class/block/%s/uevent", bd);
+					break;
+				}
+			}
+		} else if (wildcard(rootpart, "0x[a-f0-9][a-f0-9][a-f0-9]") ||
+			   wildcard(rootpart, "0x[a-f0-9][a-f0-9][a-f0-9][a-f0-9]") ||
+			   wildcard(rootpart, "[a-f0-9][a-f0-9][a-f0-9]") ||
+			   wildcard(rootpart, "[a-f0-9][a-f0-9][a-f0-9][a-f0-9]")) {
+			let devid = rootpart;
+			if (substr(devid, 0, 2) == "0x")
+				devid = substr(devid, 2);
+
+			devid = hex(devid);
+			for (let bd in get_blockdevs()) {
+				let r = get_uevent_major_minor(sprintf("/sys/class/block/%s/uevent", bd));
+				if (r && (r.major == devid / 256) && (r.minor == devid % 256)) {
+					uevent = sprintf("/sys/class/block/%s/../uevent", bd);
+					break;
+				}
+			}
+		} else if (wildcard(rootpart, "/dev/*")) {
+			uevent = sprintf("/sys/class/block/%s/../uevent", split(rootpart, '/')[-1]);
+		}
+			return get_uevent_major_minor(uevent);
+	};
+
+	// adapted from /lib/upgrade/common.sh
+	let get_partition = function(dev, num) {
+		for (let bd in get_blockdevs()) {
+			let r = get_uevent_major_minor(sprintf("/sys/class/block/%s/uevent", bd));
+			if (r.major == dev.major && r.minor == dev.minor + num) {
+				return bd;
+				break;
+			}
+		}
+		return null;
+	};
+
+	blockdev_common = {};
+	blockdev_common.get_partition = get_partition;
+	blockdev_common.get_bootdev = get_bootdev;
+%}