busybox/libbb/getopt_ulflags.c

/* vi: set sw=4 ts=4: */
/*
 * universal getopt_ulflags implementation for busybox
 *
 * Copyright (C) 2003-2005  Vladimir Oleynik  <dzo@simtreas.ru>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */

#include <getopt.h>
#include <string.h>
#include <assert.h>
#include <stdlib.h>
#include "libbb.h"

/*                  Documentation !

unsigned long
bb_getopt_ulflags (int argc, char **argv, const char *applet_opts, ...)

	The command line options must be declared in const char
	*applet_opts as a string of chars, for example:

	flags = bb_getopt_ulflags(argc, argv, "rnug");

	If one of the given options is found, a flag value is added to
	the return value (an unsigned long).

	The flag value is determined by the position of the char in
	applet_opts string.  For example, in the above case:

	flags = bb_getopt_ulflags(argc, argv, "rnug");

	"r" will add 1    (bit 1 : 0x01)
	"n" will add 2    (bit 2 : 0x02)
	"u  will add 4    (bit 3 : 0x03)
	"g" will add 8    (bit 4 : 0x04)

	 and so on.  You can also look at the return value as a bit
	 field and each option sets one of bits.

 ":"    If one of the options requires an argument, then add a ":"
	after the char in applet_opts and provide a pointer to store
	the argument.  For example:

	char *pointer_to_arg_for_a;
	char *pointer_to_arg_for_b;
	char *pointer_to_arg_for_c;
	char *pointer_to_arg_for_d;

	flags = bb_getopt_ulflags(argc, argv, "a:b:c:d:",
			 &pointer_to_arg_for_a, &pointer_to_arg_for_b,
			 &pointer_to_arg_for_c, &pointer_to_arg_for_d);

	The type of the pointer (char* or llist_t *) may be controlled
	by the "*" special character that is set in the external string
	bb_opt_complementally (see below for more info).

static const struct option bb_default_long_options[]

	This struct allows you to define long options.  The syntax for
	declaring the array is just like that of getopt's longopts.
	(see getopt(3))

	static const struct option applet_long_options[] = {
		{ "verbose", 0, 0, v },
		{ 0, 0, 0, 0 }
	};
	bb_applet_long_options = applet_long_options;

	The last argument (val) can undefined from applet_opts.
	If you use this, then:
	- return bit have next position after short options
	- if has_arg is not "no_argument", use ptr for arg also
	- bb_opt_complementally have effects for this too

	Note: a good applet will make long options configurable via the
	config process and not a required feature.  The current standard
	is to name the config option CONFIG_FEATURE_<applet>_LONG_OPTIONS.

const char *bb_opt_complementally

 ":"    The colon (":") is used to separate groups of two or more chars
	and/or groups of chars and special characters (stating some
	conditions to be checked).

 "abc"  If groups of two or more chars are specified, the first char
	is the main option and the other chars are secondary options.
	Their flags will be turned on if the main option is found even
	if they are not specifed on the command line.  For example:

	bb_opt_complementally = "abc";

	flags = bb_getopt_ulflags(argc, argv, "abcd")

	If getopt() finds "-a" on the command line, then
	bb_getopt_ulflags's return value will be as if "-a -b -c" were
	found.

Special characters:

 "-"    A dash between two options causes the second of the two
	to be unset (and ignored or triggered) if it is given on
	the command line.

	For example:
	The du applet has the options "-s" and "-d depth".  If
	bb_getopt_ulflags finds -s, then -d is unset or if it finds -d
	then -s is unset.  (Note:  busybox implements the GNU
	"--max-depth" option as "-d".)  To obtain this behavior, you
	set bb_opt_complementally = "s-d:d-s".  Only one flag value is
	added to bb_getopt_ulflags's return value depending on the
	position of the options on the command line.  If one of the
	two options requires an argument pointer (":" in applet_opts
	as in "d:") optarg is set accordingly.

	char *smax_print_depth;

	bb_opt_complementally = "s-d:d-s:x-x";
	opt = bb_getopt_ulflags(argc, argv, "sd:x", &smax_print_depth);

	if (opt & 2) {
		 max_print_depth = bb_xgetularg10_bnd(smax_print_depth,
			     0, INT_MAX);
	}
	if(opt & 4)
		printf("Detected odd -x usaging\n");

 "~"    A tilde between two options, or between an option and a group
	of options, means that they are mutually exclusive.  Unlike
	the "-" case above, an error will be forced if the options
	are used together.

	For example:
	The cut applet must have only one type of list specified, so
	-b, -c and -f are mutally exclusive and should raise an error
	if specified together.  In this case you must set
	bb_opt_complementally = "b~cf:c~bf:f~bc".  If two of the
	mutually exclusive options are found, bb_getopt_ulflags's
	return value will have the error flag set (BB_GETOPT_ERROR) so
	that we can check for it:

	if (flags & BB_GETOPT_ERROR)
		bb_show_usage();

 "!"    If previous point set BB_GETOPT_ERROR, don`t return and call
	previous example internally

 "*"    A star after a char in bb_opt_complementally means that the
	option can occur multiple times:

	For example:
	The grep applet can have one or more "-e pattern" arguments.
	In this case you should use bb_getopt_ulflags() as follows:

	llist_t *patterns = NULL;

	(this pointer must be initializated to NULL if the list is empty
	as required by *llist_add_to(llist_t *old_head, char *new_item).)

	bb_opt_complementally = "e*";

	bb_getopt_ulflags(argc, argv, "e:", &patterns);
	$ grep -e user -e root /etc/passwd
	root:x:0:0:root:/root:/bin/bash
	user:x:500:500::/home/user:/bin/bash
*/

const char *bb_opt_complementally;

typedef struct {
	unsigned char opt;
	char list_flg;
	unsigned long switch_on;
	unsigned long switch_off;
	unsigned long incongruously;
	void **optarg;               /* char **optarg or llist_t **optarg */
} t_complementally;

/* You can set bb_applet_long_options for parse called long options */

static const struct option bb_default_long_options[] = {
/*      { "help", 0, NULL, '?' }, */
	{ 0, 0, 0, 0 }
};

const struct option *bb_applet_long_options = bb_default_long_options;

unsigned long
bb_getopt_ulflags (int argc, char **argv, const char *applet_opts, ...)
{
	unsigned long flags = 0;
	t_complementally complementally[sizeof(flags) * 8 + 1];
	int c;
	const unsigned char *s;
	t_complementally *on_off;
	va_list p;
	const struct option *l_o;
	char flg_show_usage_if_error = 0;

	va_start (p, applet_opts);

	/* skip GNU extension */
	s = applet_opts;
	if(*s == '+' || *s == '-')
		s++;

	c = 0;
	on_off = complementally;
	for (; *s; s++) {
		if(c >= (sizeof(flags)*8))
			break;
		on_off->opt = *s;
		on_off->switch_on = (1 << c);
		on_off->list_flg = 0;
		on_off->switch_off = 0;
		on_off->incongruously = 0;
		on_off->optarg = NULL;
		if (s[1] == ':') {
			on_off->optarg = va_arg (p, void **);
			do
				s++;
			while (s[1] == ':');
		}
		on_off++;
		c++;
	}
	on_off->opt = 0;

	for(l_o = bb_applet_long_options; l_o->name; l_o++) {
		for(on_off = complementally; on_off->opt != 0; on_off++)
			if(on_off->opt == l_o->val)
				break;
		if(on_off->opt == 0) {
			if(c >= (sizeof(flags)*8))
				break;
			on_off->opt = l_o->val;
			on_off->switch_on = (1 << c);
			on_off->list_flg = 0;
			on_off->switch_off = 0;
			on_off->incongruously = 0;
			if(l_o->has_arg != no_argument)
				on_off->optarg = va_arg (p, void **);
			else
				on_off->optarg = NULL;
			on_off++;
			on_off->opt = 0;
			c++;
		}
	}
	c = 0;
	for (s = bb_opt_complementally; s && *s; s++) {
		t_complementally *pair;

		if (*s == ':') {
			c = 0;
			continue;
		}
		if (c)
			continue;
		if(*s == '!') {
			flg_show_usage_if_error = '!';
			continue;
		}
		for (on_off = complementally; on_off->opt; on_off++)
			if (on_off->opt == *s)
				break;
		pair = on_off;
		for(s++; *s && *s != ':'; s++) {
			if (*s == '-' || *s == '~') {
				c = *s;
			} else if(*s == '*') {
				pair->list_flg++;
			} else {
				unsigned long *pair_switch = &(pair->switch_on);
				if(c)
					pair_switch = c == '-' ? &(pair->switch_off) : &(pair->incongruously);
				for (on_off = complementally; on_off->opt; on_off++)
					if (on_off->opt == *s) {
						*pair_switch |= on_off->switch_on;
						break;
					}
			}
		}
		s--;
	}

	while ((c = getopt_long (argc, argv, applet_opts,
				 bb_applet_long_options, NULL)) > 0) {
		unsigned long trigger;

		for (on_off = complementally; on_off->opt != c; on_off++) {
			if(!on_off->opt)
				bb_show_usage ();
		}
		if(flags & on_off->incongruously) {
			if(flg_show_usage_if_error)
				bb_show_usage ();
			flags |= BB_GETOPT_ERROR;
		}
		trigger = on_off->switch_on & on_off->switch_off;
		flags &= ~(on_off->switch_off ^ trigger);
		flags |= on_off->switch_on ^ trigger;
		flags ^= trigger;
		if(on_off->list_flg) {
			*(llist_t **)(on_off->optarg) =
				llist_add_to(*(llist_t **)(on_off->optarg), optarg);
		} else if (on_off->optarg) {
			*(char **)(on_off->optarg) = optarg;
		}
	}

	return flags;
}