kvmtool/util/parse-options.c - poc/vm-api - Git at Google

 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>

 #include <stdbool.h>

 /* user defined includes */
 #include <linux/types.h>
 #include <kvm/util.h>
 #include <kvm/parse-options.h>
 #include <kvm/strbuf.h>

 #define OPT_SHORT 1
 #define OPT_UNSET 2

 static int opterror(const struct option *opt, const char *reason, int flags)
 {
 	if (flags & OPT_SHORT)
 		return pr_err("switch `%c' %s", opt->short_name, reason);
 	if (flags & OPT_UNSET)
 		return pr_err("option `no-%s' %s", opt->long_name, reason);
 	return pr_err("option `%s' %s", opt->long_name, reason);
 }

 static int get_arg(struct parse_opt_ctx_t *p, const struct option *opt,
 		int flags, const char **arg)
 {
 	if (p->opt) {
 		*arg = p->opt;
 		p->opt = NULL;
 	} else if ((opt->flags & PARSE_OPT_LASTARG_DEFAULT) && (p->argc == 1 ||
 				**(p->argv + 1) == '-')) {
 		*arg = (const char *)opt->defval;
 	} else if (p->argc > 1) {
 		p->argc--;
 		*arg = *++p->argv;
 	} else
 		return opterror(opt, "requires a value", flags);
 	return 0;
 }

 static int readnum(const struct option *opt, int flags,
 		   const char *str, char **end)
 {
 	switch (opt->type) {
 	case OPTION_INTEGER:
 		*(int *)opt->value = strtol(str, end, 0);
 		break;
 	case OPTION_UINTEGER:
 		*(unsigned int *)opt->value = strtol(str, end, 0);
 		break;
 	case OPTION_LONG:
 		*(long *)opt->value = strtol(str, end, 0);
 		break;
 	case OPTION_U64:
 		*(u64 *)opt->value = strtoull(str, end, 0);
 		break;
 	default:
 		return opterror(opt, "invalid numeric conversion", flags);
 	}

 	return 0;
 }

 static int get_value(struct parse_opt_ctx_t *p,
 		const struct option *opt, int flags)
 {
 	const char *s, *arg = NULL;
 	const int unset = flags & OPT_UNSET;

 	if (unset && p->opt)
 		return opterror(opt, "takes no value", flags);
 	if (unset && (opt->flags & PARSE_OPT_NONEG))
 		return opterror(opt, "isn't available", flags);

 	if (!(flags & OPT_SHORT) && p->opt) {
 		switch (opt->type) {
 		case OPTION_CALLBACK:
 			if (!(opt->flags & PARSE_OPT_NOARG))
 				break;
 		/* FALLTHROUGH */
 		case OPTION_BOOLEAN:
 		case OPTION_INCR:
 		case OPTION_BIT:
 		case OPTION_SET_UINT:
 		case OPTION_SET_PTR:
 			return opterror(opt, "takes no value", flags);
 		case OPTION_END:
 		case OPTION_ARGUMENT:
 		case OPTION_GROUP:
 		case OPTION_STRING:
 		case OPTION_INTEGER:
 		case OPTION_UINTEGER:
 		case OPTION_LONG:
 		case OPTION_U64:
 		default:
 			break;
 		}
 	}

 	switch (opt->type) {
 	case OPTION_BIT:
 		if (unset)
 			*(int *)opt->value &= ~opt->defval;
 		else
 			*(int *)opt->value |= opt->defval;
 		return 0;

 	case OPTION_BOOLEAN:
 		*(bool *)opt->value = unset ? false : true;
 		return 0;

 	case OPTION_INCR:
 		*(int *)opt->value = unset ? 0 : *(int *)opt->value + 1;
 		return 0;

 	case OPTION_SET_UINT:
 		*(unsigned int *)opt->value = unset ? 0 : opt->defval;
 		return 0;

 	case OPTION_SET_PTR:
 		*(void **)opt->value = unset ? NULL : (void *)opt->defval;
 		return 0;

 	case OPTION_STRING:
 		if (unset)
 			*(const char **)opt->value = NULL;
 		else if (opt->flags & PARSE_OPT_OPTARG && !p->opt)
 			*(const char **)opt->value = (const char *)opt->defval;
 		else
 			return get_arg(p, opt, flags,
 					(const char **)opt->value);
 		return 0;

 	case OPTION_CALLBACK:
 		if (unset)
 			return (*opt->callback)(opt, NULL, 1) ? (-1) : 0;
 		if (opt->flags & PARSE_OPT_NOARG)
 			return (*opt->callback)(opt, NULL, 0) ? (-1) : 0;
 		if (opt->flags & PARSE_OPT_OPTARG && !p->opt)
 			return (*opt->callback)(opt, NULL, 0) ? (-1) : 0;
 		if (get_arg(p, opt, flags, &arg))
 			return -1;
 		return (*opt->callback)(opt, arg, 0) ? (-1) : 0;

 	case OPTION_INTEGER:
 		if (unset) {
 			*(int *)opt->value = 0;
 			return 0;
 		}
 		if (opt->flags & PARSE_OPT_OPTARG && !p->opt) {
 			*(int *)opt->value = opt->defval;
 			return 0;
 		}
 		if (get_arg(p, opt, flags, &arg))
 			return -1;
 		return readnum(opt, flags, arg, (char **)&s);

 	case OPTION_UINTEGER:
 		if (unset) {
 			*(unsigned int *)opt->value = 0;
 			return 0;
 		}
 		if (opt->flags & PARSE_OPT_OPTARG && !p->opt) {
 			*(unsigned int *)opt->value = opt->defval;
 			return 0;
 		}
 		if (get_arg(p, opt, flags, &arg))
 			return -1;
 		return readnum(opt, flags, arg, (char **)&s);

 	case OPTION_LONG:
 		if (unset) {
 			*(long *)opt->value = 0;
 			return 0;
 		}
 		if (opt->flags & PARSE_OPT_OPTARG && !p->opt) {
 			*(long *)opt->value = opt->defval;
 			return 0;
 		}
 		if (get_arg(p, opt, flags, &arg))
 			return -1;
 		return readnum(opt, flags, arg, (char **)&s);

 	case OPTION_U64:
 		if (unset) {
 			*(u64 *)opt->value = 0;
 			return 0;
 		}
 		if (opt->flags & PARSE_OPT_OPTARG && !p->opt) {
 			*(u64 *)opt->value = opt->defval;
 			return 0;
 		}
 		if (get_arg(p, opt, flags, &arg))
 			return -1;
 		return readnum(opt, flags, arg, (char **)&s);

 	case OPTION_END:
 	case OPTION_ARGUMENT:
 	case OPTION_GROUP:
 	default:
 		die("should not happen, someone must be hit on the forehead");
 	}
 }

 #define USAGE_OPTS_WIDTH 24
 #define USAGE_GAP         2

 static int usage_with_options_internal(const char * const *usagestr,
 		const struct option *opts, int full)
 {
 	if (!usagestr)
 		return PARSE_OPT_HELP;

 	fprintf(stderr, "\n usage: %s\n", *usagestr++);
 	while (*usagestr && **usagestr)
 		fprintf(stderr, "    or: %s\n", *usagestr++);
 	while (*usagestr) {
 		fprintf(stderr, "%s%s\n",
 				**usagestr ? "    " : "",
 				*usagestr);
 		usagestr++;
 	}

 	if (opts->type != OPTION_GROUP)
 		fputc('\n', stderr);

 	for (; opts->type != OPTION_END; opts++) {
 		size_t pos;
 		int pad;

 		if (opts->type == OPTION_GROUP) {
 			fputc('\n', stderr);
 			if (*opts->help)
 				fprintf(stderr, "%s\n", opts->help);
 			continue;
 		}
 		if (!full && (opts->flags & PARSE_OPT_HIDDEN))
 			continue;

 		pos = fprintf(stderr, "    ");
 		if (opts->short_name)
 			pos += fprintf(stderr, "-%c", opts->short_name);
 		else
 			pos += fprintf(stderr, "    ");

 		if (opts->long_name && opts->short_name)
 			pos += fprintf(stderr, ", ");
 		if (opts->long_name)
 			pos += fprintf(stderr, "--%s", opts->long_name);

 		switch (opts->type) {
 		case OPTION_ARGUMENT:
 			break;
 		case OPTION_LONG:
 		case OPTION_U64:
 		case OPTION_INTEGER:
 		case OPTION_UINTEGER:
 			if (opts->flags & PARSE_OPT_OPTARG)
 				if (opts->long_name)
 					pos += fprintf(stderr, "[=<n>]");
 				else
 					pos += fprintf(stderr, "[<n>]");
 			else
 				pos += fprintf(stderr, " <n>");
 			break;
 		case OPTION_CALLBACK:
 			if (opts->flags & PARSE_OPT_NOARG)
 				break;
 		/* FALLTHROUGH */
 		case OPTION_STRING:
 			if (opts->argh) {
 				if (opts->flags & PARSE_OPT_OPTARG)
 					if (opts->long_name)
 						pos += fprintf(stderr, "[=<%s>]", opts->argh);
 					else
 						pos += fprintf(stderr, "[<%s>]", opts->argh);
 				else
 					pos += fprintf(stderr, " <%s>", opts->argh);
 			} else {
 				if (opts->flags & PARSE_OPT_OPTARG)
 					if (opts->long_name)
 						pos += fprintf(stderr, "[=...]");
 					else
 						pos += fprintf(stderr, "[...]");
 				else
 					pos += fprintf(stderr, " ...");
 			}
 				break;
 		default: /* OPTION_{BIT,BOOLEAN,SET_UINT,SET_PTR} */
 		case OPTION_END:
 		case OPTION_GROUP:
 		case OPTION_BIT:
 		case OPTION_BOOLEAN:
 		case OPTION_INCR:
 		case OPTION_SET_UINT:
 		case OPTION_SET_PTR:
 			break;
 		}
 		if (pos <= USAGE_OPTS_WIDTH)
 			pad = USAGE_OPTS_WIDTH - pos;
 		else {
 			fputc('\n', stderr);
 			pad = USAGE_OPTS_WIDTH;
 		}
 		fprintf(stderr, "%*s%s\n", pad + USAGE_GAP, "", opts->help);
 	}
 	fputc('\n', stderr);

 	return PARSE_OPT_HELP;
 }

 void usage_with_options(const char * const *usagestr,
 		const struct option *opts)
 {
 	usage_with_options_internal(usagestr, opts, 0);
 	exit(129);
 }

 static void check_typos(const char *arg, const struct option *options)
 {
 	if (strlen(arg) < 3)
 		return;

 	if (!prefixcmp(arg, "no-")) {
 		pr_err("did you mean `--%s` (with two dashes ?)", arg);
 		exit(129);
 	}

 	for (; options->type != OPTION_END; options++) {
 		if (!options->long_name)
 			continue;
 		if (!prefixcmp(options->long_name, arg)) {
 			pr_err("did you mean `--%s` (with two dashes ?)", arg);
 			exit(129);
 		}
 	}
 }

 static int parse_options_usage(const char * const *usagestr,
 		const struct option *opts)
 {
 	return usage_with_options_internal(usagestr, opts, 0);
 }

 static int parse_short_opt(struct parse_opt_ctx_t *p,
         const struct option *options)
 {
 	for (; options->type != OPTION_END; options++) {
 		if (options->short_name == *p->opt) {
 			p->opt = p->opt[1] ? p->opt + 1 : NULL;
 			return get_value(p, options, OPT_SHORT);
 		}
 	}
 	return -2;
 }

 static int parse_long_opt(struct parse_opt_ctx_t *p, const char *arg,
 		const struct option *options)
 {
 	const char *arg_end = strchr(arg, '=');
 	const struct option *abbrev_option = NULL, *ambiguous_option = NULL;
 	int abbrev_flags = 0, ambiguous_flags = 0;

 	if (!arg_end)
 		arg_end = arg + strlen(arg);

 	for (; options->type != OPTION_END; options++) {
 		const char *rest;
 		int flags = 0;

 		if (!options->long_name)
 			continue;

 		rest = skip_prefix(arg, options->long_name);
 		if (options->type == OPTION_ARGUMENT) {
 			if (!rest)
 				continue;
 			if (*rest == '=')
 				return opterror(options, "takes no value",
 						flags);
 			if (*rest)
 				continue;
 			p->out[p->cpidx++] = arg - 2;
 			return 0;
 		}
 		if (!rest) {
 			/* abbreviated? */
 			if (!strncmp(options->long_name, arg, arg_end - arg)) {
 is_abbreviated:
 				if (abbrev_option) {
 					/*
 					 * If this is abbreviated, it is
 					 * ambiguous. So when there is no
 					 * exact match later, we need to
 					 * error out.
 					 */
 					ambiguous_option = abbrev_option;
 					ambiguous_flags = abbrev_flags;
 				}
 				if (!(flags & OPT_UNSET) && *arg_end)
 					p->opt = arg_end + 1;
 				abbrev_option = options;
 				abbrev_flags = flags;
 				continue;
 			}
 			/* negated and abbreviated very much? */
 			if (!prefixcmp("no-", arg)) {
 				flags |= OPT_UNSET;
 				goto is_abbreviated;
 			}
 			/* negated? */
 			if (strncmp(arg, "no-", 3))
 				continue;
 			flags |= OPT_UNSET;
 			rest = skip_prefix(arg + 3, options->long_name);
 			/* abbreviated and negated? */
 			if (!rest && !prefixcmp(options->long_name, arg + 3))
 				goto is_abbreviated;
 			if (!rest)
 				continue;
 		}
 		if (*rest) {
 			if (*rest != '=')
 				continue;
 			p->opt = rest + 1;
 		}
 		return get_value(p, options, flags);
 	}

 	if (ambiguous_option)
 		return pr_err("Ambiguous option: %s "
 				"(could be --%s%s or --%s%s)",
 				arg,
 				(ambiguous_flags & OPT_UNSET) ?  "no-" : "",
 				ambiguous_option->long_name,
 				(abbrev_flags & OPT_UNSET) ?  "no-" : "",
 				abbrev_option->long_name);
 	if (abbrev_option)
 		return get_value(p, abbrev_option, abbrev_flags);
 	return -2;
 }


 static void parse_options_start(struct parse_opt_ctx_t *ctx, int argc,
 		const char **argv, int flags)
 {
 	memset(ctx, 0, sizeof(*ctx));
 	ctx->argc = argc;
 	ctx->argv = argv;
 	ctx->out  = argv;
 	ctx->cpidx = ((flags & PARSE_OPT_KEEP_ARGV0) != 0);
 	ctx->flags = flags;
 	if ((flags & PARSE_OPT_KEEP_UNKNOWN) &&
 			(flags & PARSE_OPT_STOP_AT_NON_OPTION))
 		die("STOP_AT_NON_OPTION and KEEP_UNKNOWN don't go together");
 }

 static int parse_options_end(struct parse_opt_ctx_t *ctx)
 {
 	memmove(ctx->out + ctx->cpidx, ctx->argv, ctx->argc * sizeof(*ctx->out));
 	ctx->out[ctx->cpidx + ctx->argc] = NULL;
 	return ctx->cpidx + ctx->argc;
 }


 static int parse_options_step(struct parse_opt_ctx_t *ctx,
 		const struct option *options, const char * const usagestr[])
 {
 	int internal_help = !(ctx->flags & PARSE_OPT_NO_INTERNAL_HELP);

 	/* we must reset ->opt, unknown short option leave it dangling */
 	ctx->opt = NULL;

 	for (; ctx->argc; ctx->argc--, ctx->argv++) {
 		const char *arg = ctx->argv[0];

 		if (*arg != '-' || !arg[1]) {
 			if (ctx->flags & PARSE_OPT_STOP_AT_NON_OPTION)
 				break;
 			ctx->out[ctx->cpidx++] = ctx->argv[0];
 			continue;
 		}

 		if (arg[1] != '-') {
 			ctx->opt = arg + 1;
 			if (internal_help && *ctx->opt == 'h')
 				return parse_options_usage(usagestr, options);
 			switch (parse_short_opt(ctx, options)) {
 			case -1:
 				return parse_options_usage(usagestr, options);
 			case -2:
 				goto unknown;
 			default:
 				break;
 			}
 			if (ctx->opt)
 				check_typos(arg + 1, options);
 			while (ctx->opt) {
 				if (internal_help && *ctx->opt == 'h')
 					return parse_options_usage(usagestr,
 							options);
 				switch (parse_short_opt(ctx, options)) {
 				case -1:
 					return parse_options_usage(usagestr,
 							options);
 				case -2:
 					/* fake a short option thing to hide
 					 * the fact that we may have
 					 * started to parse aggregated stuff
 					 *
 					 * This is leaky, too bad.
 					 */
 					ctx->argv[0] = strdup(ctx->opt - 1);
 					*(char *)ctx->argv[0] = '-';
 					goto unknown;
 				default:
 					break;
 				}
 			}
 			continue;
 		}

 		if (!arg[2]) { /* "--" */
 			if (!(ctx->flags & PARSE_OPT_KEEP_DASHDASH)) {
 				ctx->argc--;
 				ctx->argv++;
 			}
 			break;
 		}

 		if (internal_help && !strcmp(arg + 2, "help-all"))
 			return usage_with_options_internal(usagestr, options,
 					1);
 		if (internal_help && !strcmp(arg + 2, "help"))
 			return parse_options_usage(usagestr, options);
 		switch (parse_long_opt(ctx, arg + 2, options)) {
 		case -1:
 			return parse_options_usage(usagestr, options);
 		case -2:
 			goto unknown;
 		default:
 			break;
 		}
 		continue;
 unknown:
 		if (!(ctx->flags & PARSE_OPT_KEEP_UNKNOWN))
 			return PARSE_OPT_UNKNOWN;
 		ctx->out[ctx->cpidx++] = ctx->argv[0];
 		ctx->opt = NULL;
 	}
 	return PARSE_OPT_DONE;
 }

 int parse_options(int argc, const char **argv, const struct option *options,
 		const char * const usagestr[], int flags)
 {
 	struct parse_opt_ctx_t ctx;

 	parse_options_start(&ctx, argc, argv, flags);
 	switch (parse_options_step(&ctx, options, usagestr)) {
 	case PARSE_OPT_HELP:
 		exit(129);
 	case PARSE_OPT_DONE:
 		break;
 	default: /* PARSE_OPT_UNKNOWN */
 		if (ctx.argv[0][1] == '-') {
 			pr_err("unknown option `%s'", ctx.argv[0] + 2);
 		} else {
 			pr_err("unknown switch `%c'", *ctx.opt);
 		}
 		usage_with_options(usagestr, options);
 	}

 	return parse_options_end(&ctx);
 }
	#include <stdlib.h>
	#include <stdio.h>
	#include <string.h>
	#include <unistd.h>

	#include <stdbool.h>

	/* user defined includes */
	#include <linux/types.h>
	#include <kvm/util.h>
	#include <kvm/parse-options.h>
	#include <kvm/strbuf.h>

	#define OPT_SHORT 1
	#define OPT_UNSET 2

	static int opterror(const struct option opt, const char reason, int flags)
	{
	if (flags & OPT_SHORT)
	return pr_err("switch `%c' %s", opt->short_name, reason);
	if (flags & OPT_UNSET)
	return pr_err("option `no-%s' %s", opt->long_name, reason);
	return pr_err("option `%s' %s", opt->long_name, reason);
	}

	static int get_arg(struct parse_opt_ctx_t p, const struct option opt,
	int flags, const char **arg)
	{
	if (p->opt) {
	*arg = p->opt;
	p->opt = NULL;
	} else if ((opt->flags & PARSE_OPT_LASTARG_DEFAULT) && (p->argc == 1 \|\|
	**(p->argv + 1) == '-')) {
	arg = (const char )opt->defval;
	} else if (p->argc > 1) {
	p->argc--;
	arg = ++p->argv;
	} else
	return opterror(opt, "requires a value", flags);
	return 0;
	}

	static int readnum(const struct option *opt, int flags,
	const char str, char *end)
	{
	switch (opt->type) {
	case OPTION_INTEGER:
	(int )opt->value = strtol(str, end, 0);
	break;
	case OPTION_UINTEGER:
	(unsigned int )opt->value = strtol(str, end, 0);
	break;
	case OPTION_LONG:
	(long )opt->value = strtol(str, end, 0);
	break;
	case OPTION_U64:
	(u64 )opt->value = strtoull(str, end, 0);
	break;
	default:
	return opterror(opt, "invalid numeric conversion", flags);
	}

	return 0;
	}

	static int get_value(struct parse_opt_ctx_t *p,
	const struct option *opt, int flags)
	{
	const char s, arg = NULL;
	const int unset = flags & OPT_UNSET;

	if (unset && p->opt)
	return opterror(opt, "takes no value", flags);
	if (unset && (opt->flags & PARSE_OPT_NONEG))
	return opterror(opt, "isn't available", flags);

	if (!(flags & OPT_SHORT) && p->opt) {
	switch (opt->type) {
	case OPTION_CALLBACK:
	if (!(opt->flags & PARSE_OPT_NOARG))
	break;
	/* FALLTHROUGH */
	case OPTION_BOOLEAN:
	case OPTION_INCR:
	case OPTION_BIT:
	case OPTION_SET_UINT:
	case OPTION_SET_PTR:
	return opterror(opt, "takes no value", flags);
	case OPTION_END:
	case OPTION_ARGUMENT:
	case OPTION_GROUP:
	case OPTION_STRING:
	case OPTION_INTEGER:
	case OPTION_UINTEGER:
	case OPTION_LONG:
	case OPTION_U64:
	default:
	break;
	}
	}

	switch (opt->type) {
	case OPTION_BIT:
	if (unset)
	(int )opt->value &= ~opt->defval;
	else
	(int )opt->value \|= opt->defval;
	return 0;

	case OPTION_BOOLEAN:
	(bool )opt->value = unset ? false : true;
	return 0;

	case OPTION_INCR:
	(int )opt->value = unset ? 0 : (int )opt->value + 1;
	return 0;

	case OPTION_SET_UINT:
	(unsigned int )opt->value = unset ? 0 : opt->defval;
	return 0;

	case OPTION_SET_PTR:
	(void )opt->value = unset ? NULL : (void )opt->defval;
	return 0;

	case OPTION_STRING:
	if (unset)
	(const char *)opt->value = NULL;
	else if (opt->flags & PARSE_OPT_OPTARG && !p->opt)
	(const char )opt->value = (const char )opt->defval;
	else
	return get_arg(p, opt, flags,
	(const char **)opt->value);
	return 0;

	case OPTION_CALLBACK:
	if (unset)
	return (*opt->callback)(opt, NULL, 1) ? (-1) : 0;
	if (opt->flags & PARSE_OPT_NOARG)
	return (*opt->callback)(opt, NULL, 0) ? (-1) : 0;
	if (opt->flags & PARSE_OPT_OPTARG && !p->opt)
	return (*opt->callback)(opt, NULL, 0) ? (-1) : 0;
	if (get_arg(p, opt, flags, &arg))
	return -1;
	return (*opt->callback)(opt, arg, 0) ? (-1) : 0;

	case OPTION_INTEGER:
	if (unset) {
	(int )opt->value = 0;
	return 0;
	}
	if (opt->flags & PARSE_OPT_OPTARG && !p->opt) {
	(int )opt->value = opt->defval;
	return 0;
	}
	if (get_arg(p, opt, flags, &arg))
	return -1;
	return readnum(opt, flags, arg, (char **)&s);

	case OPTION_UINTEGER:
	if (unset) {
	(unsigned int )opt->value = 0;
	return 0;
	}
	if (opt->flags & PARSE_OPT_OPTARG && !p->opt) {
	(unsigned int )opt->value = opt->defval;
	return 0;
	}
	if (get_arg(p, opt, flags, &arg))
	return -1;
	return readnum(opt, flags, arg, (char **)&s);

	case OPTION_LONG:
	if (unset) {
	(long )opt->value = 0;
	return 0;
	}
	if (opt->flags & PARSE_OPT_OPTARG && !p->opt) {
	(long )opt->value = opt->defval;
	return 0;
	}
	if (get_arg(p, opt, flags, &arg))
	return -1;
	return readnum(opt, flags, arg, (char **)&s);

	case OPTION_U64:
	if (unset) {
	(u64 )opt->value = 0;
	return 0;
	}
	if (opt->flags & PARSE_OPT_OPTARG && !p->opt) {
	(u64 )opt->value = opt->defval;
	return 0;
	}
	if (get_arg(p, opt, flags, &arg))
	return -1;
	return readnum(opt, flags, arg, (char **)&s);

	case OPTION_END:
	case OPTION_ARGUMENT:
	case OPTION_GROUP:
	default:
	die("should not happen, someone must be hit on the forehead");
	}
	}

	#define USAGE_OPTS_WIDTH 24
	#define USAGE_GAP 2

	static int usage_with_options_internal(const char * const *usagestr,
	const struct option *opts, int full)
	{
	if (!usagestr)
	return PARSE_OPT_HELP;

	fprintf(stderr, "\n usage: %s\n", *usagestr++);
	while (usagestr && *usagestr)
	fprintf(stderr, " or: %s\n", *usagestr++);
	while (*usagestr) {
	fprintf(stderr, "%s%s\n",
	**usagestr ? " " : "",
	*usagestr);
	usagestr++;
	}

	if (opts->type != OPTION_GROUP)
	fputc('\n', stderr);

	for (; opts->type != OPTION_END; opts++) {
	size_t pos;
	int pad;

	if (opts->type == OPTION_GROUP) {
	fputc('\n', stderr);
	if (*opts->help)
	fprintf(stderr, "%s\n", opts->help);
	continue;
	}
	if (!full && (opts->flags & PARSE_OPT_HIDDEN))
	continue;

	pos = fprintf(stderr, " ");
	if (opts->short_name)
	pos += fprintf(stderr, "-%c", opts->short_name);
	else
	pos += fprintf(stderr, " ");

	if (opts->long_name && opts->short_name)
	pos += fprintf(stderr, ", ");
	if (opts->long_name)
	pos += fprintf(stderr, "--%s", opts->long_name);

	switch (opts->type) {
	case OPTION_ARGUMENT:
	break;
	case OPTION_LONG:
	case OPTION_U64:
	case OPTION_INTEGER:
	case OPTION_UINTEGER:
	if (opts->flags & PARSE_OPT_OPTARG)
	if (opts->long_name)
	pos += fprintf(stderr, "[=<n>]");
	else
	pos += fprintf(stderr, "[<n>]");
	else
	pos += fprintf(stderr, " <n>");
	break;
	case OPTION_CALLBACK:
	if (opts->flags & PARSE_OPT_NOARG)
	break;
	/* FALLTHROUGH */
	case OPTION_STRING:
	if (opts->argh) {
	if (opts->flags & PARSE_OPT_OPTARG)
	if (opts->long_name)
	pos += fprintf(stderr, "[=<%s>]", opts->argh);
	else
	pos += fprintf(stderr, "[<%s>]", opts->argh);
	else
	pos += fprintf(stderr, " <%s>", opts->argh);
	} else {
	if (opts->flags & PARSE_OPT_OPTARG)
	if (opts->long_name)
	pos += fprintf(stderr, "[=...]");
	else
	pos += fprintf(stderr, "[...]");
	else
	pos += fprintf(stderr, " ...");
	}
	break;
	default: /* OPTION_{BIT,BOOLEAN,SET_UINT,SET_PTR} */
	case OPTION_END:
	case OPTION_GROUP:
	case OPTION_BIT:
	case OPTION_BOOLEAN:
	case OPTION_INCR:
	case OPTION_SET_UINT:
	case OPTION_SET_PTR:
	break;
	}
	if (pos <= USAGE_OPTS_WIDTH)
	pad = USAGE_OPTS_WIDTH - pos;
	else {
	fputc('\n', stderr);
	pad = USAGE_OPTS_WIDTH;
	}
	fprintf(stderr, "%*s%s\n", pad + USAGE_GAP, "", opts->help);
	}
	fputc('\n', stderr);

	return PARSE_OPT_HELP;
	}

	void usage_with_options(const char * const *usagestr,
	const struct option *opts)
	{
	usage_with_options_internal(usagestr, opts, 0);
	exit(129);
	}

	static void check_typos(const char arg, const struct option options)
	{
	if (strlen(arg) < 3)
	return;

	if (!prefixcmp(arg, "no-")) {
	pr_err("did you mean `--%s` (with two dashes ?)", arg);
	exit(129);
	}

	for (; options->type != OPTION_END; options++) {
	if (!options->long_name)
	continue;
	if (!prefixcmp(options->long_name, arg)) {
	pr_err("did you mean `--%s` (with two dashes ?)", arg);
	exit(129);
	}
	}
	}

	static int parse_options_usage(const char * const *usagestr,
	const struct option *opts)
	{
	return usage_with_options_internal(usagestr, opts, 0);
	}

	static int parse_short_opt(struct parse_opt_ctx_t *p,
	const struct option *options)
	{
	for (; options->type != OPTION_END; options++) {
	if (options->short_name == *p->opt) {
	p->opt = p->opt[1] ? p->opt + 1 : NULL;
	return get_value(p, options, OPT_SHORT);
	}
	}
	return -2;
	}

	static int parse_long_opt(struct parse_opt_ctx_t p, const char arg,
	const struct option *options)
	{
	const char *arg_end = strchr(arg, '=');
	const struct option abbrev_option = NULL, ambiguous_option = NULL;
	int abbrev_flags = 0, ambiguous_flags = 0;

	if (!arg_end)
	arg_end = arg + strlen(arg);

	for (; options->type != OPTION_END; options++) {
	const char *rest;
	int flags = 0;

	if (!options->long_name)
	continue;

	rest = skip_prefix(arg, options->long_name);
	if (options->type == OPTION_ARGUMENT) {
	if (!rest)
	continue;
	if (*rest == '=')
	return opterror(options, "takes no value",
	flags);
	if (*rest)
	continue;
	p->out[p->cpidx++] = arg - 2;
	return 0;
	}
	if (!rest) {
	/* abbreviated? */
	if (!strncmp(options->long_name, arg, arg_end - arg)) {
	is_abbreviated:
	if (abbrev_option) {
	/*
	* If this is abbreviated, it is
	* ambiguous. So when there is no
	* exact match later, we need to
	* error out.
	*/
	ambiguous_option = abbrev_option;
	ambiguous_flags = abbrev_flags;
	}
	if (!(flags & OPT_UNSET) && *arg_end)
	p->opt = arg_end + 1;
	abbrev_option = options;
	abbrev_flags = flags;
	continue;
	}
	/* negated and abbreviated very much? */
	if (!prefixcmp("no-", arg)) {
	flags \|= OPT_UNSET;
	goto is_abbreviated;
	}
	/* negated? */
	if (strncmp(arg, "no-", 3))
	continue;
	flags \|= OPT_UNSET;
	rest = skip_prefix(arg + 3, options->long_name);
	/* abbreviated and negated? */
	if (!rest && !prefixcmp(options->long_name, arg + 3))
	goto is_abbreviated;
	if (!rest)
	continue;
	}
	if (*rest) {
	if (*rest != '=')
	continue;
	p->opt = rest + 1;
	}
	return get_value(p, options, flags);
	}

	if (ambiguous_option)
	return pr_err("Ambiguous option: %s "
	"(could be --%s%s or --%s%s)",
	arg,
	(ambiguous_flags & OPT_UNSET) ? "no-" : "",
	ambiguous_option->long_name,
	(abbrev_flags & OPT_UNSET) ? "no-" : "",
	abbrev_option->long_name);
	if (abbrev_option)
	return get_value(p, abbrev_option, abbrev_flags);
	return -2;
	}


	static void parse_options_start(struct parse_opt_ctx_t *ctx, int argc,
	const char **argv, int flags)
	{
	memset(ctx, 0, sizeof(*ctx));
	ctx->argc = argc;
	ctx->argv = argv;
	ctx->out = argv;
	ctx->cpidx = ((flags & PARSE_OPT_KEEP_ARGV0) != 0);
	ctx->flags = flags;
	if ((flags & PARSE_OPT_KEEP_UNKNOWN) &&
	(flags & PARSE_OPT_STOP_AT_NON_OPTION))
	die("STOP_AT_NON_OPTION and KEEP_UNKNOWN don't go together");
	}

	static int parse_options_end(struct parse_opt_ctx_t *ctx)
	{
	memmove(ctx->out + ctx->cpidx, ctx->argv, ctx->argc * sizeof(*ctx->out));
	ctx->out[ctx->cpidx + ctx->argc] = NULL;
	return ctx->cpidx + ctx->argc;
	}


	static int parse_options_step(struct parse_opt_ctx_t *ctx,
	const struct option options, const char const usagestr[])
	{
	int internal_help = !(ctx->flags & PARSE_OPT_NO_INTERNAL_HELP);

	/* we must reset ->opt, unknown short option leave it dangling */
	ctx->opt = NULL;

	for (; ctx->argc; ctx->argc--, ctx->argv++) {
	const char *arg = ctx->argv[0];

	if (*arg != '-' \|\| !arg[1]) {
	if (ctx->flags & PARSE_OPT_STOP_AT_NON_OPTION)
	break;
	ctx->out[ctx->cpidx++] = ctx->argv[0];
	continue;
	}

	if (arg[1] != '-') {
	ctx->opt = arg + 1;
	if (internal_help && *ctx->opt == 'h')
	return parse_options_usage(usagestr, options);
	switch (parse_short_opt(ctx, options)) {
	case -1:
	return parse_options_usage(usagestr, options);
	case -2:
	goto unknown;
	default:
	break;
	}
	if (ctx->opt)
	check_typos(arg + 1, options);
	while (ctx->opt) {
	if (internal_help && *ctx->opt == 'h')
	return parse_options_usage(usagestr,
	options);
	switch (parse_short_opt(ctx, options)) {
	case -1:
	return parse_options_usage(usagestr,
	options);
	case -2:
	/* fake a short option thing to hide
	* the fact that we may have
	* started to parse aggregated stuff
	*
	* This is leaky, too bad.
	*/
	ctx->argv[0] = strdup(ctx->opt - 1);
	(char )ctx->argv[0] = '-';
	goto unknown;
	default:
	break;
	}
	}
	continue;
	}

	if (!arg[2]) { /* "--" */
	if (!(ctx->flags & PARSE_OPT_KEEP_DASHDASH)) {
	ctx->argc--;
	ctx->argv++;
	}
	break;
	}

	if (internal_help && !strcmp(arg + 2, "help-all"))
	return usage_with_options_internal(usagestr, options,
	1);
	if (internal_help && !strcmp(arg + 2, "help"))
	return parse_options_usage(usagestr, options);
	switch (parse_long_opt(ctx, arg + 2, options)) {
	case -1:
	return parse_options_usage(usagestr, options);
	case -2:
	goto unknown;
	default:
	break;
	}
	continue;
	unknown:
	if (!(ctx->flags & PARSE_OPT_KEEP_UNKNOWN))
	return PARSE_OPT_UNKNOWN;
	ctx->out[ctx->cpidx++] = ctx->argv[0];
	ctx->opt = NULL;
	}
	return PARSE_OPT_DONE;
	}

	int parse_options(int argc, const char *argv, const struct option options,
	const char * const usagestr[], int flags)
	{
	struct parse_opt_ctx_t ctx;

	parse_options_start(&ctx, argc, argv, flags);
	switch (parse_options_step(&ctx, options, usagestr)) {
	case PARSE_OPT_HELP:
	exit(129);
	case PARSE_OPT_DONE:
	break;
	default: /* PARSE_OPT_UNKNOWN */
	if (ctx.argv[0][1] == '-') {
	pr_err("unknown option `%s'", ctx.argv[0] + 2);
	} else {
	pr_err("unknown switch `%c'", *ctx.opt);
	}
	usage_with_options(usagestr, options);
	}

	return parse_options_end(&ctx);
	}