command: refactor to use const command structure

Refactor code so the definitions may become 'static const'
and with configure_command_option_values() we update options
val_enum for actually running command option when used.

Also update _update_relative_opt() which is used for
generating man pages and command help.

Introduce enumeration for lvm2 commands - so we may
use enum cmd_COMMAND instead of string checking.

So running command now does not modified opt_names.

tools/command.c

@@ -47,7 +47,7 @@ static const struct val_name val_names[VAL_COUNT + 1] = {
 
 /* create table of option names, e.g. --foo, and corresponding enum from args.h */
 
-static struct opt_name opt_names[ARG_COUNT + 1] = {
+static const struct opt_name opt_names[ARG_COUNT + 1] = {
 #define arg(a, b, c, d, e, f, g) { # a, b, a, "--" c, d, e, f, g },
 #include "args.h"
 #undef arg
@@ -85,7 +85,7 @@ static const struct cmd_name cmd_names[CMD_COUNT + 1] = {
 #ifdef MAN_PAGE_GENERATOR
 
 static struct command_name command_names[] = {
-#define xx(a, b, c...) { # a, b, c },
+#define xx(a, b, c...) { # a, b, c, NULL, a ## _COMMAND },
 #include "commands.h"
 #undef xx
 	{ .name = NULL }
@@ -95,7 +95,7 @@ static struct command commands[COMMAND_COUNT];
 #else /* MAN_PAGE_GENERATOR */
 
 struct command_name command_names[] = {
-#define xx(a, b, c...) { # a, b, c, a},
+#define xx(a, b, c...) { # a, b, c, a, a ## _COMMAND },
 #include "commands.h"
 #undef xx
 	{ .name = NULL }
@@ -130,7 +130,7 @@ const struct lv_type *get_lv_type(int lvt_enum)
 
 /* array of pointers into opt_names[] that is sorted alphabetically (by long opt name) */
 
-static struct opt_name *opt_names_alpha[ARG_COUNT + 1];
+static const struct opt_name *opt_names_alpha[ARG_COUNT + 1];
 
 /* lvm_all is for recording options that are common for all lvm commands */
 
@@ -1517,6 +1517,7 @@ int define_commands(struct cmd_context *cmdtool, const char *run_name)
 	return 1;
 }
 
+#ifndef MAN_PAGE_GENERATOR
 /*
  * The opt_names[] table describes each option.  It is indexed by the
  * option typedef, e.g. size_ARG.  The size_ARG entry specifies the
@@ -1533,8 +1534,10 @@ int define_commands(struct cmd_context *cmdtool, const char *run_name)
  * (they are created at build time), but different commands accept different
  * types of values for the same option, e.g. one command will accept
  * signed size values (ssizemb_VAL), while another does not accept a signed
- * number, (sizemb_VAL).  This function deals with this problem by tweaking
- * the opt_names[] table at run time according to the specific command being run.
+ * number, (sizemb_VAL).
+ *
+ * To resolve the issue, at run time command 'reconfigures' its opt_names[]
+ * values by querying particular arg_enum for particular command.
  * i.e. it changes size_ARG to accept sizemb_VAL or ssizemb_VAL depending
  * on the command.
  *
@@ -1558,53 +1561,57 @@ int define_commands(struct cmd_context *cmdtool, const char *run_name)
  * so the commands[] entry for the cmd def already references the
  * correct ssizemb_VAL.
  */
-void configure_command_option_values(const char *name)
+int configure_command_option_values(const struct command_name *cname, int arg_enum, int val_enum)
 {
-	if (!strcmp(name, "lvresize")) {
-		/* relative +|- allowed for LV, + allowed for metadata */
-		opt_names[size_ARG].val_enum = ssizemb_VAL;
-		opt_names[extents_ARG].val_enum = sextents_VAL;
-		opt_names[poolmetadatasize_ARG].val_enum = psizemb_VAL;
-		return;
+	switch (cname->lvm_command_enum) {
+	case lvconvert_COMMAND:
+		switch (arg_enum) {
+		case mirrors_ARG:		return snumber_VAL;
 		}
-
-	if (!strcmp(name, "lvextend")) {
-		/* relative + allowed */
-		opt_names[size_ARG].val_enum = psizemb_VAL;
-		opt_names[extents_ARG].val_enum = pextents_VAL;
-		opt_names[poolmetadatasize_ARG].val_enum = psizemb_VAL;
-		return;
-	}
-
-	if (!strcmp(name, "lvreduce")) {
-		/* relative - allowed */
-		opt_names[size_ARG].val_enum = nsizemb_VAL;
-		opt_names[extents_ARG].val_enum = nextents_VAL;
-		return;
-	}
-
-	if (!strcmp(name, "lvconvert")) {
-		opt_names[mirrors_ARG].val_enum = snumber_VAL;
-		return;
-	}
-
-	if (!strcmp(name, "lvcreate")) {
+		break;
+	case lvcreate_COMMAND:
 		/*
-		 * lvcreate is a bit of a mess because it has previously
-		 * accepted + but used it as an absolute value, so we
-		 * have to recognize it.  (We don't want to show the +
-		 * option in man/help, though, since it's confusing,
+		 * lvcreate is accepts also sizes with + (positive) value,
+		 * so we have to recognize it.  But we don't want to show
+		 * the + option in man/help as it can be seen confusing,
 		 * so there's a special case when printing man/help
 		 * output to show sizemb_VAL/extents_VAL rather than
 		 * psizemb_VAL/pextents_VAL.)
 		 */
-		opt_names[size_ARG].val_enum = psizemb_VAL;
-		opt_names[extents_ARG].val_enum = pextents_VAL;
-		opt_names[poolmetadatasize_ARG].val_enum = psizemb_VAL;
-		opt_names[mirrors_ARG].val_enum = pnumber_VAL;
-		return;
+		switch (arg_enum) {
+		case size_ARG:			return psizemb_VAL;
+		case extents_ARG:		return pextents_VAL;
+		case poolmetadatasize_ARG:	return psizemb_VAL;
+		case mirrors_ARG:		return pnumber_VAL;
 		}
+		break;
+	case lvextend_COMMAND:
+		/* relative + allowed */
+		switch (arg_enum) {
+		case size_ARG:			return psizemb_VAL;
+		case extents_ARG:		return pextents_VAL;
+		case poolmetadatasize_ARG:	return psizemb_VAL;
+		}
+		break;
+	case lvreduce_COMMAND:
+		/* relative - allowed */
+		switch (arg_enum) {
+		case size_ARG:			return nsizemb_VAL;
+		case extents_ARG:		return nextents_VAL;
+		}
+		break;
+	case lvresize_COMMAND:
+		switch (arg_enum) {
+		case size_ARG:			return ssizemb_VAL;
+		case extents_ARG:		return sextents_VAL;
+		case poolmetadatasize_ARG:	return psizemb_VAL;
+		}
+		break;
+	}
+
+	return val_enum;
 }
+#endif
 
 /* type_LVT to "type" */
 
@@ -1644,38 +1651,49 @@ static void _print_usage_description(struct command *cmd)
 	}
 }
 
-static void _update_relative_opt(const char *name, int opt_enum, int *val_enum)
+/* Function remappas existing command definitions val_enums for printing
+ * within man pages or command's help lines */
+static int _update_relative_opt(const char *name, int opt_enum, int val_enum)
 {
 	/* check for relative sign */
+	if (!strcmp(name, "lvconvert"))
 		switch (opt_enum) {
-	case extents_ARG:
-	case mirrors_ARG:
-	case poolmetadatasize_ARG:
-	case size_ARG:
+		case mirrors_ARG:	return snumber_VAL;
+		}
+	else if (!strcmp(name, "lvcreate"))
 		/*
 		 * Suppress the [+] prefix for lvcreate which we have to
 		 * accept for backwards compat, but don't want to advertise.
+		 * 'command-lines.in' currently uses PNumber in definition
 		 */
-		if (!strcmp(name, "lvcreate")) {
-			switch (*val_enum) {
-			case psizemb_VAL:
-				*val_enum = sizemb_VAL;
-				break;
-			case pextents_VAL:
-				*val_enum = extents_VAL;
-				break;
-			case pnumber_VAL:
-				if (opt_enum == mirrors_ARG)
-					*val_enum = number_VAL;
-				break;
+		switch (opt_enum) {
+		case mirrors_ARG:	return number_VAL;
 		}
+	else if (!strcmp(name, "lvextend"))
+		switch (opt_enum) {
+		case extents_ARG:	return pextents_VAL;
+		case poolmetadatasize_ARG:
+		case size_ARG:		return psizemb_VAL;
 		}
+	else if (!strcmp(name, "lvreduce"))
+		switch (opt_enum) {
+		case extents_ARG:	return nextents_VAL;
+		case poolmetadatasize_ARG:
+		case size_ARG:		return nsizemb_VAL;
 		}
+	else if (!strcmp(name, "lvresize"))
+		switch (opt_enum) {
+		case extents_ARG:	return sextents_VAL;
+		case poolmetadatasize_ARG:
+		case size_ARG:		return ssizemb_VAL;
+		}
+
+	return val_enum;
 }
 
 static void _print_val_usage(struct command *cmd, int opt_enum, int val_enum)
 {
-	_update_relative_opt(cmd->name, opt_enum, &val_enum);
+	val_enum = _update_relative_opt(cmd->name, opt_enum, val_enum);
 
 	if (!val_names[val_enum].usage)
 		printf("%s", val_names[val_enum].name);

tools/command.h

@@ -35,6 +35,7 @@ struct command_name {
 	const char *desc; /* general command description from commands.h */
 	unsigned int flags;
 	command_fn fn; /* old style */
+	uint16_t lvm_command_enum; /* as declared in commands.h with _COMMAND */
 
 	/* union of {required,optional}_opt_args for all commands with this name */
 	uint16_t valid_args[ARG_COUNT]; /* used for getopt */
@@ -274,7 +275,7 @@ void print_usage_common_lvm(const struct command_name *cname, struct command *cm
 void print_usage_notes(const struct command_name *cname);
 void factor_common_options(void);
 int command_has_alternate_extents(const char *name);
-void configure_command_option_values(const char *name);
+int configure_command_option_values(const struct command_name *cname, int arg_enum, int val_enum);
 const struct command_name *find_command_name(const char *name);
 
 #endif

tools/command_enums.h

@@ -49,6 +49,13 @@ enum {
 #undef lvt
 };
 
+enum {
+#define xx(a, b...) a ## _COMMAND,
+#include "commands.h"
+#undef xx
+        LVM_COMMAND_COUNT
+};
+
 #define PERMITTED_READ_ONLY 	0x00000002
 /* Process all VGs if none specified on the command line. */
 #define ALL_VGS_IS_DEFAULT	0x00000004

tools/lvmcmdline.c

@@ -2021,8 +2021,6 @@ static int _usage(const char *name, int longhelp, int skip_notes)
 		return 0;
 	}
 
-	configure_command_option_values(name);
-
 	/*
 	 * Looks at all variants of each command name and figures out
 	 * which options are common to all variants (for compact output)
@@ -2200,6 +2198,7 @@ static int _process_command_line(struct cmd_context *cmd, int *argc, char ***arg
 	struct arg_values *av;
 	struct arg_value_group_list *current_group = NULL;
 	int arg_enum; /* e.g. foo_ARG */
+	int val_enum;
 	int goval;    /* the number returned from getopt_long identifying what it found */
 	int i;
 
@@ -2291,8 +2290,8 @@ static int _process_command_line(struct cmd_context *cmd, int *argc, char ***arg
 			}
 
 			av->value = optarg;
-
-			if (!get_val_name(a->val_enum)->fn(cmd, av)) {
+			val_enum = configure_command_option_values(cmd->cname, arg_enum, a->val_enum);
+			if (!get_val_name(val_enum)->fn(cmd, av)) {
 				log_error("Invalid argument for %s: %s", a->long_opt, optarg);
 				return 0;
 			}
@@ -3072,8 +3071,6 @@ int lvm_run_command(struct cmd_context *cmd, int argc, char **argv)
 
 	init_log_command(find_config_tree_bool(cmd, log_command_names_CFG, NULL), 0);
 
-	configure_command_option_values(cmd->name);
-
 	/* eliminate '-' from all options starting with -- */
 	for (i = 1; i < argc; i++) {
 

tools/man-generator.c

@@ -119,6 +119,10 @@ static const char *_lvt_enum_to_name(int lvt_enum)
 	return lv_types[lvt_enum].name;
 }
 
+static int _get_val_enum(const struct command_name *cname, int opt_enum)
+{
+	return _update_relative_opt(cname->name, opt_enum, opt_names[opt_enum].val_enum);
+}
 /*
  * FIXME: this just replicates the val usage strings
  * that officially lives in vals.h.  Should there
@@ -137,8 +141,6 @@ static void _print_val_man(const struct command_name *cname, int opt_enum, int v
 
 	_was_hyphen = 0;
 
-	_update_relative_opt(cname->name, opt_enum, &val_enum);
-
 	switch (val_enum) {
 	case sizemb_VAL:
 		printf("\\fISize\\fP[m|UNIT]");
@@ -232,7 +234,7 @@ static void _print_val_man(const struct command_name *cname, int opt_enum, int v
 
 static void _print_def_man(const struct command_name *cname, int opt_enum, struct arg_def *def, int usage, uint64_t *lv_type_bits)
 {
-	int val_enum;
+	int val_enum, tmp_val;
 	int sep = 0;
 
 	if (lv_type_bits)
@@ -264,7 +266,8 @@ static void _print_def_man(const struct command_name *cname, int opt_enum, struc
 						printf("\\fI%s\\fP", val_names[val_enum].name);
 					}
 				} else {
-					_print_val_man(cname, opt_enum, val_enum);
+					tmp_val = _update_relative_opt(cname->name, opt_enum, val_enum);
+					_print_val_man(cname, opt_enum, tmp_val);
 				}
 
 				sep = 1;
@@ -577,7 +580,7 @@ static void _print_man_usage(char *lvmname, struct command *cmd)
 			 * in opt_names[] according to the command name.
 			 */
 			printf("[ \\fB-l\\fP|\\fB--extents\\fP ");
-			_print_val_man(cname, extents_ARG, opt_names[extents_ARG].val_enum);
+			_print_val_man(cname, extents_ARG, _get_val_enum(cname, extents_ARG));
 
 			printf_hyphen(']');
 			sep = 1;
@@ -1020,7 +1023,7 @@ static void _print_man_all_options_list(const struct command_name *cname)
 			printf("    \\fB%s\\fP", _man_long_opt_name(cname->name, opt_enum));
 		}
 
-		val_enum = opt_names[opt_enum].val_enum;
+		val_enum = _get_val_enum(cname, opt_enum);
 
 		if (!val_names[val_enum].fn) {
 			/* takes no arg */
@@ -1059,7 +1062,7 @@ static void _print_man_all_options_desc(const struct command_name *cname)
 		if (!cname->all_options[opt_enum])
 			continue;
 
-		val_enum = opt_names[opt_enum].val_enum;
+		val_enum = _get_val_enum(cname, opt_enum);
 
 		if (val_names[val_enum].usage &&
 		    (strlen(val_names[val_enum].usage) > _LONG_LINE)) {
@@ -1781,9 +1784,6 @@ int main(int argc, char *argv[])
 	if (!define_commands(&cmdtool, NULL))
 		goto out_free;
 
-	if (!check)
-		configure_command_option_values(cmdname);
-
 	factor_common_options();
 
 	if (primary && cmdname)