opt: add new parse_early_args_incomplete.

If we have plugins, and those can register args, we have a problem finding
the plugin dir!  So, do a best-effort incomplete parse.

Note that this can screw up in theory if we have "--unknown --foo" since we
don't know if unknown takes an argument (in which case, ignore --foo) or
not.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

ccan/opt/opt.c

@@ -207,14 +207,15 @@ bool opt_parse(int *argc, char *argv[], void (*errlog)(const char *fmt, ...))
 	/* This helps opt_usage. */
 	opt_argv0 = argv[0];
 
-	while ((ret = parse_one(argc, argv, 0, &offset, errlog)) == 1);
+	while ((ret = parse_one(argc, argv, 0, &offset, errlog, false)) == 1);
 
 	/* parse_one returns 0 on finish, -1 on error */
 	return (ret == 0);
 }
 
-bool opt_early_parse(int argc, char *argv[],
-		     void (*errlog)(const char *fmt, ...))
+static bool early_parse(int argc, char *argv[],
+			void (*errlog)(const char *fmt, ...),
+			bool ignore_unknown)
 {
 	int ret;
 	unsigned off = 0;
@@ -226,7 +227,7 @@ bool opt_early_parse(int argc, char *argv[],
 	/* This helps opt_usage. */
 	opt_argv0 = argv[0];
 
-	while ((ret = parse_one(&argc, tmpargv, OPT_EARLY, &off, errlog)) == 1);
+	while ((ret = parse_one(&argc, tmpargv, OPT_EARLY, &off, errlog, ignore_unknown)) == 1);
 
 	opt_alloc.free(tmpargv);
 
@@ -234,6 +235,18 @@ bool opt_early_parse(int argc, char *argv[],
 	return (ret == 0);
 }
 
+bool opt_early_parse(int argc, char *argv[],
+		     void (*errlog)(const char *fmt, ...))
+{
+	return early_parse(argc, argv, errlog, false);
+}
+
+bool opt_early_parse_incomplete(int argc, char *argv[],
+				void (*errlog)(const char *fmt, ...))
+{
+	return early_parse(argc, argv, errlog, true);
+}
+
 void opt_free_table(void)
 {
 	opt_alloc.free(opt_table);

ccan/opt/opt.h

@@ -286,6 +286,30 @@ bool opt_parse(int *argc, char *argv[], void (*errlog)(const char *fmt, ...));
 bool opt_early_parse(int argc, char *argv[],
 		     void (*errlog)(const char *fmt, ...));
 
+/**
+ * opt_early_parse_incomplete - parse early arguments, ignoring unknown ones.
+ * @argc: argc
+ * @argv: argv array.
+ * @errlog: the function to print errors
+ *
+ * If you have plugins, you might need to do early parsing (eg. to find the
+ * plugin directory) but you don't know what options the plugins will want.
+ *
+ * Thus, this function is just like opt_early_parse, but ignores unknown options.
+ *
+ * Example:
+ *	if (!opt_early_parse_incomplete(argc, argv, opt_log_stderr)) {
+ *		printf("You screwed up, aborting!\n");
+ *		exit(1);
+ *	}
+ *
+ * See Also:
+ *	opt_early_parse()
+ */
+bool opt_early_parse_incomplete(int argc, char *argv[],
+				void (*errlog)(const char *fmt, ...));
+
+
 /**
  * opt_free_table - reset the opt library.
  *

ccan/opt/parse.c

@@ -30,7 +30,7 @@ static void consume_option(int *argc, char *argv[], unsigned optnum)
 
 /* Returns 1 if argument consumed, 0 if all done, -1 on error. */
 int parse_one(int *argc, char *argv[], enum opt_type is_early, unsigned *offset,
-	      void (*errlog)(const char *fmt, ...))
+	      void (*errlog)(const char *fmt, ...), bool unknown_ok)
 {
 	unsigned i, arg, len;
 	const char *o, *optarg = NULL;
@@ -67,10 +67,13 @@ int parse_one(int *argc, char *argv[], enum opt_type is_early, unsigned *offset,
 				continue;
 			break;
 		}
-		if (!o)
+		if (!o) {
+			if (unknown_ok)
+				goto ok;
 			return parse_err(errlog, argv[0],
 					 argv[arg], strlen(argv[arg]),
 					 "unrecognized option");
+		}
 		/* For error messages, we include the leading '--' */
 		o -= 2;
 		len += 2;
@@ -82,10 +85,15 @@ int parse_one(int *argc, char *argv[], enum opt_type is_early, unsigned *offset,
 			(*offset)++;
 			break;
 		}
-		if (!o)
+		if (!o) {
+			if (unknown_ok) {
+				(*offset)++;
+				goto ok;
+			}
 			return parse_err(errlog, argv[0],
 					 argv[arg], strlen(argv[arg]),
 					 "unrecognized option");
+		}
 		/* For error messages, we include the leading '-' */
 		o--;
 		len = 2;
@@ -120,6 +128,7 @@ int parse_one(int *argc, char *argv[], enum opt_type is_early, unsigned *offset,
 		return -1;
 	}
 
+ok:
 	/* If no more letters in that short opt, reset offset. */
 	if (*offset && !argv[arg][*offset + 1])
 		*offset = 0;

ccan/opt/private.h

@@ -22,6 +22,6 @@ struct opt_alloc {
 extern struct opt_alloc opt_alloc;
 
 int parse_one(int *argc, char *argv[], enum opt_type is_early, unsigned *offset,
-	      void (*errlog)(const char *fmt, ...));
+	      void (*errlog)(const char *fmt, ...), bool unknown_ok);
 
 #endif /* CCAN_OPT_PRIVATE_H */

ccan/opt/test/run-early_incomplete.c

+/* With errlog == NULL, we never get a "failure". */
+#include <ccan/tap/tap.h>
+#include <stdlib.h>
+#include <ccan/opt/opt.c>
+#include <ccan/opt/usage.c>
+#include <ccan/opt/helpers.c>
+#include <ccan/opt/parse.c>
+#include "utils.h"
+
+int main(int argc, char *argv[])
+{
+	plan_tests(8);
+
+	/* Simple short args.*/
+	opt_register_noarg("-a", test_noarg, NULL, "All");
+	opt_register_early_noarg("-b|--blong", test_noarg, NULL, "All");
+
+	/* This is OK. */
+	ok1(parse_early_args_incomplete(&argc, &argv, "-c", NULL));
+	ok1(test_cb_called == 0);
+
+	/* Skips letters correctly */
+	ok1(parse_early_args_incomplete(&argc, &argv, "-ca", NULL));
+	ok1(test_cb_called == 0); /* a is not an early arg! */
+
+	test_cb_called = 0;
+	ok1(parse_early_args_incomplete(&argc, &argv, "-bca", NULL));
+	ok1(test_cb_called == 1);
+
+	test_cb_called = 0;
+	ok1(parse_early_args_incomplete(&argc, &argv, "--unknown", "--also-unknown", "--blong", NULL));
+	ok1(test_cb_called == 1);
+
+	/* parse_args allocates argv */
+	free(argv);
+	return exit_status();
+}

ccan/opt/test/utils.c

@@ -103,6 +103,29 @@ bool parse_early_args(int *argc, char ***argv, ...)
 	return opt_early_parse(*argc, *argv, save_err_output);
 }
 
+bool parse_early_args_incomplete(int *argc, char ***argv, ...)
+{
+	char **a;
+	va_list ap;
+
+	va_start(ap, argv);
+	*argc = 1;
+	a = malloc(sizeof(*a) * (*argc + 1));
+	a[0] = (*argv)[0];
+	while ((a[*argc] = va_arg(ap, char *)) != NULL) {
+		(*argc)++;
+		a = realloc(a, sizeof(*a) * (*argc + 1));
+	}
+
+	if (allocated)
+		free(*argv);
+
+	*argv = a;
+	allocated = true;
+
+	return opt_early_parse_incomplete(*argc, *argv, save_err_output);
+}
+
 struct opt_table short_table[] = {
 	/* Short opts, different args. */
 	OPT_WITHOUT_ARG("-a", test_noarg, "a", "Description of a"),

ccan/opt/test/utils.h

@@ -5,6 +5,7 @@
 
 bool parse_args(int *argc, char ***argv, ...);
 bool parse_early_args(int *argc, char ***argv, ...);
+bool parse_early_args_incomplete(int *argc, char ***argv, ...);
 extern char *err_output;
 void save_err_output(const char *fmt, ...);
 void reset_options(void);