dumpconfig: add --type, --atversion and --validate arg

lvm dumpconfig [--type {current|default|missing|new}] [--atversion] [--validate]

This patch adds above-mentioned args to lvm dumpconfig and it maps them
to creation and writing out a configuration tree of a specific type
(see also previous commit):

  - current maps to CFG_TYPE_CURRENT
  - default maps to CFG_TYPE_DEFAULT
  - missing maps to CFG_TYPE_MISSING
  - new maps to CFG_TYPE_NEW

If --type is not defined, dumpconfig defaults to "--type current"
which is the original behaviour of dumpconfig before all these changes.

The --validate option just validates current configuration tree
(lvm.conf/--config) and it writes a simple status message:

  "LVM configuration valid" or "LVM configuration invalid"

1 files changed, 77 insertions, 3 deletions

diff --git a/tools/dumpconfig.c b/tools/dumpconfig.c
index c5f522652..ac90a95c3 100644
--- a/tools/dumpconfig.c
+++ b/tools/dumpconfig.c
@@ -15,14 +15,88 @@
 
 #include "tools.h"
 
+static int _get_vsn(struct cmd_context *cmd, unsigned int *major,
+		    unsigned int *minor, unsigned int *patchlevel)
+{
+	const char *atversion = arg_str_value(cmd, atversion_ARG, NULL);
+
+	if (!atversion)
+		atversion = LVM_VERSION;
+
+	if (sscanf(atversion, "%u.%u.%u", major, minor, patchlevel) != 3) {
+		log_error("Incorrect version format.");
+		return 0;
+	}
+
+	return 1;
+}
+
 int dumpconfig(struct cmd_context *cmd, int argc, char **argv)
 {
 	const char *file = arg_str_value(cmd, file_ARG, NULL);
+	const char *type = arg_str_value(cmd, configtype_ARG, "current");
+	unsigned int major, minor, patchlevel;
+	struct config_def_tree_spec tree_spec = {0};
+	struct dm_config_tree *cft;
+	int r = ECMD_PROCESSED;
+
+	if (arg_count(cmd, configtype_ARG) && arg_count(cmd, validate_ARG)) {
+		log_error("Only one of --type and --validate permitted.");
+		return EINVALID_CMD_LINE;
+	}
+
+	if (arg_count(cmd, atversion_ARG) && !arg_count(cmd, configtype_ARG)) {
+		log_error("--atversion requires --type");
+		return EINVALID_CMD_LINE;
+	}
+
+	if (arg_count(cmd, validate_ARG)) {
+		if (config_def_check(cmd, 1, 1, 0)) {
+			log_print("LVM configuration valid.");
+			return ECMD_PROCESSED;
+		} else {
+			log_error("LVM configuration invalid.");
+			return ECMD_FAILED;
+		}
+	}
+
+	if (!strcmp(type, "current")) {
+		if (arg_count(cmd, atversion_ARG)) {
+			log_error("--atversion has no effect with --type current");
+			return EINVALID_CMD_LINE;
+		}
+		cft = cmd->cft;
+		tree_spec.type = CFG_DEF_TREE_CURRENT;
+		config_def_check(cmd, 1, 1, 1);
+	}
 
-	if (!config_write(cmd->cft, file, argc, argv)) {
+	else if (!strcmp(type, "default"))
+		tree_spec.type = CFG_DEF_TREE_DEFAULT;
+	else if (!strcmp(type, "missing"))
+		tree_spec.type = CFG_DEF_TREE_MISSING;
+	else if (!strcmp(type, "new"))
+		tree_spec.type = CFG_DEF_TREE_NEW;
+	else {
+		log_error("Incorrect type of configuration specified. "
+			  "Expected one of: current, default, missing, new.");
+		return EINVALID_CMD_LINE;
+	}
+
+	if (tree_spec.type != CFG_DEF_TREE_CURRENT) {
+		if (!_get_vsn(cmd, &major, &minor, &patchlevel))
+			return EINVALID_CMD_LINE;
+		tree_spec.version = vsn(major, minor, patchlevel);
+		cft = config_def_create_tree(&tree_spec);
+	}
+
+	if (!config_write(cft, file, argc, argv)) {
 		stack;
-		return ECMD_FAILED;
+		r = ECMD_FAILED;
 	}
 
-	return ECMD_PROCESSED;
+	/* cmd->cft (the "current" tree) is destroyed with cmd context destroy! */
+	if (tree_spec.type != CFG_DEF_TREE_CURRENT && cft)
+		dm_pool_destroy(cft->mem);
+
+	return r;
 }