- Add gc_usage field to g_command structure. This will allow to define

  usage for a subcommand, so no 'usage' function has to be implemented
  in class library.
- Bump version number as it breaks ABI, but don't provide backward
  compatibility, because there are probably no external consumers of this
  geom(8).
This allows to print more precise usage for standard commands and simplify
class libraries a bit.

MFC after:	1 week

2 files changed, 52 insertions, 56 deletions

diff --git a/sbin/geom/core/geom.c b/sbin/geom/core/geom.c
index 62a1a7a388a0..67f19191ff66 100644
--- a/sbin/geom/core/geom.c
+++ b/sbin/geom/core/geom.c
@@ -56,7 +56,6 @@ static char comm[MAXPATHLEN], *class_name = NULL, *gclass_name = NULL;
 static uint32_t *version = NULL;
 static int verbose = 0;
 static struct g_command *class_commands = NULL;
-static void (*usage)(const char *name);
 
 #define	GEOM_CLASS_CMDS	0x01
 #define	GEOM_STD_CMDS	0x02
@@ -70,73 +69,75 @@ static void std_load(struct gctl_req *req, unsigned flags);
 static void std_unload(struct gctl_req *req, unsigned flags);
 
 struct g_command std_commands[] = {
-	{ "help", 0, std_help, G_NULL_OPTS },
-	{ "list", 0, std_list, G_NULL_OPTS },
+	{ "help", 0, std_help, G_NULL_OPTS, NULL },
+	{ "list", 0, std_list, G_NULL_OPTS,
+	    "[name ...]"
+	},
 	{ "status", 0, std_status,
 	    {
 		{ 's', "script", NULL, G_TYPE_NONE },
 		G_OPT_SENTINEL
-	    }
+	    },
+	    "[-s] [name ...]"
 	},
-	{ "load", G_FLAG_VERBOSE | G_FLAG_LOADKLD, std_load, G_NULL_OPTS },
-	{ "unload", G_FLAG_VERBOSE, std_unload, G_NULL_OPTS },
+	{ "load", G_FLAG_VERBOSE | G_FLAG_LOADKLD, std_load, G_NULL_OPTS, NULL },
+	{ "unload", G_FLAG_VERBOSE, std_unload, G_NULL_OPTS, NULL },
 	G_CMD_SENTINEL
 };
 
 static void
-std_usage(const char *name)
+usage_command(struct g_command *cmd, const char *prefix)
 {
-	struct g_command *cmd;
 	struct g_option *opt;
-	unsigned i, j;
+	unsigned i;
 
+	fprintf(stderr, "%s %s %s", prefix, comm, cmd->gc_name);
+	if (cmd->gc_usage != NULL) {
+		fprintf(stderr, " %s\n", cmd->gc_usage);
+		return;
+	}
+	if ((cmd->gc_flags & G_FLAG_VERBOSE) != 0)
+		fprintf(stderr, " [-v]");
 	for (i = 0; ; i++) {
-		cmd = &class_commands[i];
-		if (cmd->gc_name == NULL)
+		opt = &cmd->gc_options[i];
+		if (opt->go_name == NULL)
 			break;
-		fprintf(stderr, "%s %s %s %s", i == 0 ? "usage:" : "      ",
-		    name, class_name, cmd->gc_name);
-		if ((cmd->gc_flags & G_FLAG_VERBOSE) != 0)
-			fprintf(stderr, " [-v]");
-		for (j = 0; ; j++) {
-			opt = &cmd->gc_options[j];
-			if (opt->go_name == NULL)
-				break;
-			if (opt->go_val != NULL || opt->go_type == G_TYPE_NONE)
-				fprintf(stderr, " [");
-			else
-				fprintf(stderr, " ");
-			fprintf(stderr, "-%c", opt->go_char);
-			if (opt->go_type != G_TYPE_NONE)
-				fprintf(stderr, " %s", opt->go_name);
-			if (opt->go_val != NULL || opt->go_type == G_TYPE_NONE)
-				fprintf(stderr, "]");
-		}
-		fprintf(stderr, " ...\n");
+		if (opt->go_val != NULL || opt->go_type == G_TYPE_NONE)
+			fprintf(stderr, " [");
+		else
+			fprintf(stderr, " ");
+		fprintf(stderr, "-%c", opt->go_char);
+		if (opt->go_type != G_TYPE_NONE)
+			fprintf(stderr, " %s", opt->go_name);
+		if (opt->go_val != NULL || opt->go_type == G_TYPE_NONE)
+			fprintf(stderr, "]");
 	}
-	exit(EXIT_FAILURE);
+	fprintf(stderr, "\n");
 }
 
 static void
-geom_usage(void)
+usage(void)
 {
 
 	if (class_name == NULL) {
 		errx(EXIT_FAILURE, "usage: %s <class> <command> [options]",
 		    "geom");
 	} else {
+		struct g_command *cmd;
 		const char *prefix;
 		unsigned i;
 
-		if (usage == NULL)
-			prefix = "usage:";
-		else {
-			usage(comm);
-			prefix = "      ";
+		prefix = "usage:";
+		if (class_commands != NULL) {
+			for (i = 0; ; i++) {
+				cmd = &class_commands[i];
+				if (cmd->gc_name == NULL)
+					break;
+				usage_command(cmd, prefix);
+				prefix = "      ";
+			}
 		}
 		for (i = 0; ; i++) {
-			struct g_command *cmd;
-
 			cmd = &std_commands[i];
 			if (cmd->gc_name == NULL)
 				break;
@@ -147,10 +148,7 @@ geom_usage(void)
 			 */
 			if (find_command(cmd->gc_name, GEOM_CLASS_CMDS) != NULL)
 				continue;
-			fprintf(stderr, "%s %s %s", prefix, comm, cmd->gc_name);
-			if ((cmd->gc_flags & G_FLAG_VERBOSE) != 0)
-				fprintf(stderr, " [-v]");
-			fprintf(stderr, "\n");
+			usage_command(cmd, prefix);
 			prefix = "      ";
 		}
 		exit(EXIT_FAILURE);
@@ -287,11 +285,11 @@ parse_arguments(struct g_command *cmd, struct gctl_req *req, int *argc,
 		/* Options passed to kernel. */
 		opt = find_option(cmd, ch);
 		if (opt == NULL)
-			geom_usage();
+			usage();
 		if (G_OPT_ISDONE(opt)) {
 			fprintf(stderr, "Flag '%c' specified twice.\n",
 			    opt->go_char);
-			geom_usage();
+			usage();
 		}
 		G_OPT_DONE(opt);
 
@@ -320,7 +318,7 @@ parse_arguments(struct g_command *cmd, struct gctl_req *req, int *argc,
 			if (opt->go_val == NULL) {
 				fprintf(stderr, "Flag '%c' not specified.\n",
 				    opt->go_char);
-				geom_usage();
+				usage();
 			} else {
 				if (opt->go_type == G_TYPE_NUMBER) {
 					gctl_ro_param(req, opt->go_name,
@@ -409,7 +407,7 @@ run_command(int argc, char *argv[])
 		cmd = find_command(argv[0], GEOM_STD_CMDS);
 		if (cmd == NULL) {
 			fprintf(stderr, "Unknown command: %s\n", argv[0]);
-			geom_usage();
+			usage();
 		}
 		if (!std_available(cmd->gc_name)) {
 			fprintf(stderr, "Command '%s' not available.\n",
@@ -511,9 +509,6 @@ load_library(void)
 		dlclose(dlh);
 		exit(EXIT_FAILURE);
 	}
-	usage = dlsym(dlh, "usage");
-	if (usage == NULL)
-		usage = std_usage;
 }
 
 /*
@@ -541,11 +536,11 @@ get_class(int *argc, char ***argv)
 	snprintf(comm, sizeof(comm), "%s", basename((*argv)[0]));
 	if (strcmp(comm, "geom") == 0) {
 		if (*argc < 2)
-			geom_usage();
+			usage();
 		else if (*argc == 2) {
 			if (strcmp((*argv)[1], "-h") == 0 ||
 			    strcmp((*argv)[1], "help") == 0) {
-				geom_usage();
+				usage();
 			}
 		}
 		strlcatf(comm, sizeof(comm), " %s", (*argv)[1]);
@@ -562,7 +557,7 @@ get_class(int *argc, char ***argv)
 	set_class_name();
 	load_library();
 	if (*argc < 1)
-		geom_usage();
+		usage();
 }
 
 int
@@ -678,7 +673,7 @@ static void
 std_help(struct gctl_req *req __unused, unsigned flags __unused)
 {
 
-	geom_usage();
+	usage();
 }
 
 static int
diff --git a/sbin/geom/core/geom.h b/sbin/geom/core/geom.h
index 06b97a0c2154..e4d94beee161 100644
--- a/sbin/geom/core/geom.h
+++ b/sbin/geom/core/geom.h
@@ -28,7 +28,7 @@
 
 #ifndef _GEOM_H_
 #define	_GEOM_H_
-#define	G_LIB_VERSION	0
+#define	G_LIB_VERSION	1
 
 #define	G_FLAG_NONE	0x0000
 #define	G_FLAG_VERBOSE	0x0001
@@ -44,7 +44,7 @@
 
 #define G_OPT_SENTINEL	{ '\0', NULL, NULL, G_TYPE_NONE }
 #define G_NULL_OPTS	{ G_OPT_SENTINEL }
-#define	G_CMD_SENTINEL	{ NULL, 0, NULL, G_NULL_OPTS }
+#define	G_CMD_SENTINEL	{ NULL, 0, NULL, G_NULL_OPTS, NULL }
 
 struct g_option {
 	char		 go_char;
@@ -58,5 +58,6 @@ struct g_command {
 	unsigned	 gc_flags;
 	void		(*gc_func)(struct gctl_req *, unsigned);
 	struct g_option	gc_options[G_OPT_MAX];
+	const char	*gc_usage;
 };
 #endif	/* !_GEOM_H_ */