From 7ee89d1aa63efc8d703ca5533390524a429f9c69 Mon Sep 17 00:00:00 2001
From: Helen Koike <helen.koike@collabora.com>
Date: Tue, 23 Apr 2019 15:58:36 -0300
Subject: [PATCH 1/2] dm: init: convert dm= to dm-mod.create=

Upstream code uses dm-mod.create= option to allow boot to device-mapper
without an initr*.

Add a dm= kernel parameter that just converts the given format to
dm-mod.create= format.
This patch is meant to be reverted once all ChromeOS build/userspace
code migrate to the new format.

BUG=chromium:960168
TEST=The following script passes all tests:
https://gitlab.collabora.com/koike/dm-cmdline-test/tree/chrome

Signed-off-by: Helen Koike <helen.koike@collabora.com>
Signed-off-by: Guenter Roeck <groeck@chromium.org>
(cherry picked from commit dc985b6cd66b29cb3cf0a9643606ccbd1d275f12)
Signed-off-by: Roy Yang <royyang@google.com>

BUG=b/154072035
TEST=manually build and boot correctly using kvm
SOURCE=CHROMEOS(dc985b6cd66b29cb3cf0a9643606ccbd1d275f12),
kernel-next/chromeos-5.4-md
Change-Id: I10ef47147a4f424d5ed00bc75ea3276e7dcd7e43
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/1180
Reviewed-by: Vaibhav Rustagi <vaibhavrustagi@google.com>
---
 drivers/md/dm-init.c | 251 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 251 insertions(+)

diff --git a/drivers/md/dm-init.c b/drivers/md/dm-init.c
index b0c45c6ebe0b..188b23cd2de8 100644
--- a/drivers/md/dm-init.c
+++ b/drivers/md/dm-init.c
@@ -301,3 +301,254 @@ late_initcall(dm_init_init);
 
 module_param(create, charp, 0);
 MODULE_PARM_DESC(create, "Create a mapped device in early boot");
+
+/* ---------------------------------------------------------------
+ * ChromeOS shim - convert dm= format to dm-mod.create= format
+ * ---------------------------------------------------------------
+ */
+
+struct dm_chrome_target {
+	char *field[4];
+};
+
+struct dm_chrome_dev {
+	char *name, *uuid, *mode;
+	unsigned int num_targets;
+	struct dm_chrome_target targets[DM_MAX_TARGETS];
+};
+
+static char __init *dm_chrome_parse_target(char *str, struct dm_chrome_target *tgt)
+{
+	unsigned int i;
+
+	tgt->field[0] = str;
+	/* Delimit first 3 fields that are separated by space */
+	for (i = 0; i < ARRAY_SIZE(tgt->field) - 1; i++) {
+		tgt->field[i + 1] = str_field_delimit(&tgt->field[i], ' ');
+		if (!tgt->field[i + 1])
+			return NULL;
+	}
+	/* Delimit last field that can be terminated by comma */
+	return str_field_delimit(&tgt->field[i], ',');
+}
+
+static char __init *dm_chrome_parse_dev(char *str, struct dm_chrome_dev *dev)
+{
+	char *target, *num;
+	unsigned int i;
+
+	if (!str)
+		return ERR_PTR(-EINVAL);
+
+	target = str_field_delimit(&str, ',');
+	if (!target)
+		return ERR_PTR(-EINVAL);
+
+	/* Delimit first 3 fields that are separated by space */
+	dev->name = str;
+	dev->uuid = str_field_delimit(&dev->name, ' ');
+	if (!dev->uuid)
+		return ERR_PTR(-EINVAL);
+
+	dev->mode = str_field_delimit(&dev->uuid, ' ');
+	if (!dev->mode)
+		return ERR_PTR(-EINVAL);
+
+	/* num is optional */
+	num = str_field_delimit(&dev->mode, ' ');
+	if (!num)
+		dev->num_targets = 1;
+	else {
+		/* Delimit num and check if it the last field */
+		if(str_field_delimit(&num, ' '))
+			return ERR_PTR(-EINVAL);
+		if (kstrtouint(num, 0, &dev->num_targets))
+			return ERR_PTR(-EINVAL);
+	}
+
+	if (dev->num_targets > DM_MAX_TARGETS) {
+		DMERR("too many targets %u > %d",
+		      dev->num_targets, DM_MAX_TARGETS);
+		return ERR_PTR(-EINVAL);
+	}
+
+	for (i = 0; i < dev->num_targets - 1; i++) {
+		target = dm_chrome_parse_target(target, &dev->targets[i]);
+		if (!target)
+			return ERR_PTR(-EINVAL);
+	}
+	/* The last one can return NULL if it reaches the end of str */
+	return dm_chrome_parse_target(target, &dev->targets[i]);
+}
+
+static char __init *dm_chrome_convert(struct dm_chrome_dev *devs, unsigned int num_devs)
+{
+	char *str = kmalloc(DM_MAX_STR_SIZE, GFP_KERNEL);
+	char *p = str;
+	unsigned int i, j;
+	int ret;
+
+	if (!str)
+		return ERR_PTR(-ENOMEM);
+
+	for (i = 0; i < num_devs; i++) {
+		if (!strcmp(devs[i].uuid, "none"))
+			devs[i].uuid = "";
+		ret = snprintf(p, DM_MAX_STR_SIZE - (p - str),
+			       "%s,%s,,%s",
+			       devs[i].name,
+			       devs[i].uuid,
+			       devs[i].mode);
+		if (ret < 0)
+			goto out;
+		p += ret;
+
+		for (j = 0; j < devs[i].num_targets; j++) {
+			ret = snprintf(p, DM_MAX_STR_SIZE - (p - str),
+				       ",%s %s %s %s",
+				       devs[i].targets[j].field[0],
+				       devs[i].targets[j].field[1],
+				       devs[i].targets[j].field[2],
+				       devs[i].targets[j].field[3]);
+			if (ret < 0)
+				goto out;
+			p += ret;
+		}
+		if (i < num_devs - 1) {
+			ret = snprintf(p, DM_MAX_STR_SIZE - (p - str), ";");
+			if (ret < 0)
+				goto out;
+			p += ret;
+		}
+	}
+
+	return str;
+
+out:
+	kfree(str);
+	return ERR_PTR(ret);
+}
+
+/**
+ * dm_chrome_shim - convert old dm= format used in chromeos to the new
+ * upstream format.
+ *
+ * ChromeOS old format
+ * -------------------
+ * <device>        ::= [<num>] <device-mapper>+
+ * <device-mapper> ::= <head> "," <target>+
+ * <head>          ::= <name> <uuid> <mode> [<num>]
+ * <target>        ::= <start> <length> <type> <options> ","
+ * <mode>          ::= "ro" | "rw"
+ * <uuid>          ::= xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx | "none"
+ * <type>          ::= "verity" | "bootcache" | ...
+ *
+ * Example:
+ * 2 vboot none ro 1,
+ *     0 1768000 bootcache
+ *       device=aa55b119-2a47-8c45-946a-5ac57765011f+1
+ *       signature=76e9be054b15884a9fa85973e9cb274c93afadb6
+ *       cache_start=1768000 max_blocks=100000 size_limit=23 max_trace=20000,
+ *   vroot none ro 1,
+ *     0 1740800 verity payload=254:0 hashtree=254:0 hashstart=1740800 alg=sha1
+ *       root_hexdigest=76e9be054b15884a9fa85973e9cb274c93afadb6
+ *       salt=5b3549d54d6c7a3837b9b81ed72e49463a64c03680c47835bef94d768e5646fe
+ *
+ * Notes:
+ *  1. uuid is a label for the device and we set it to "none".
+ *  2. The <num> field will be optional initially and assumed to be 1.
+ *     Once all the scripts that set these fields have been set, it will
+ *     be made mandatory.
+ */
+
+static char *chrome_create;
+
+static int __init dm_chrome_shim(char *arg) {
+	if (!arg || create)
+		return -EINVAL;
+	chrome_create = arg;
+	return 0;
+}
+
+static int __init dm_chrome_parse_devices(void)
+{
+	struct dm_chrome_dev *devs;
+	unsigned int num_devs, i;
+	char *next, *base_str;
+	int ret = 0;
+
+	/* Verify if dm-mod.create was not used */
+	if (!chrome_create || create)
+		return -EINVAL;
+
+	if (strlen(chrome_create) >= DM_MAX_STR_SIZE) {
+		DMERR("Argument is too big. Limit is %d\n", DM_MAX_STR_SIZE);
+		return -EINVAL;
+	}
+
+	base_str = kstrdup(chrome_create, GFP_KERNEL);
+	if (!base_str)
+		return -ENOMEM;
+
+	next = str_field_delimit(&base_str, ' ');
+	if (!next) {
+		ret = -EINVAL;
+		goto out_str;
+	}
+
+	/* if first field is not the optional <num> field */
+	if (kstrtouint(base_str, 0, &num_devs)) {
+		num_devs = 1;
+		/* rewind next pointer */
+		next = base_str;
+	}
+
+	if (num_devs > DM_MAX_DEVICES) {
+		DMERR("too many devices %u > %d", num_devs, DM_MAX_DEVICES);
+		ret = -EINVAL;
+		goto out_str;
+	}
+
+	devs = kcalloc(num_devs, sizeof(*devs), GFP_KERNEL);
+	if (!devs)
+		return -ENOMEM;
+
+	/* restore string */
+	strcpy(base_str, chrome_create);
+
+	/* parse devices */
+	for (i = 0; i < num_devs; i++) {
+		next = dm_chrome_parse_dev(next, &devs[i]);
+		if (IS_ERR(next)) {
+			DMERR("couldn't parse device");
+			ret = PTR_ERR(next);
+			goto out_devs;
+		}
+	}
+
+	create = dm_chrome_convert(devs, num_devs);
+	if (IS_ERR(create)) {
+		ret = PTR_ERR(create);
+		goto out_devs;
+	}
+
+	DMDEBUG("Converting:\n\tdm=\"%s\"\n\tdm-mod.create=\"%s\"\n",
+		chrome_create, create);
+
+	/* Call upstream code */
+	dm_init_init();
+
+	kfree(create);
+
+out_devs:
+	create = NULL;
+	kfree(devs);
+out_str:
+	kfree(base_str);
+
+	return ret;
+}
+
+late_initcall(dm_chrome_parse_devices);
+
+__setup("dm=", dm_chrome_shim);
-- 
2.36.0.550.gb090851708-goog