busybox/libbb/getopt32.c

/* vi: set sw=4 ts=4: */
/*
 * universal getopt32 implementation for busybox
 *
 * Copyright (C) 2003-2005  Vladimir Oleynik  <dzo@simtreas.ru>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

#include <getopt.h>
#include "libbb.h"

/*      Documentation

uint32_t
getopt32(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 = getopt32(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 = getopt32(argv, "rnug");

        "r" will add 1    (bit 0)
        "n" will add 2    (bit 1)
        "u" will add 4    (bit 2)
        "g" will add 8    (bit 3)

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

        On exit, global variable optind is set so that if you
        will do argc -= optind; argv += optind; then
        argc will be equal to number of remaining non-option
        arguments, first one would be in argv[0], next in argv[1] and so on
        (options and their parameters will be moved into argv[]
        positions prior to argv[optind]).

 ":"    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 = getopt32(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 separator that is set in the external string
        opt_complementary (see below for more info).

 "::"   If option can have an *optional* argument, then add a "::"
        after its char in applet_opts and provide a pointer to store
        the argument.  Note that optional arguments _must_
        immediately follow the option: -oparam, not -o param.

 "+"    If the first character in the applet_opts string is a plus,
        then option processing will stop as soon as a non-option is
        encountered in the argv array.  Useful for applets like env
        which should not process arguments to subprograms:
        env -i ls -d /
        Here we want env to process just the '-i', not the '-d'.

const char *applet_long_options

        This struct allows you to define long options:

        static const char applet_longopts[] ALIGN1 =
		//"name\0" has_arg val
		"verbose\0" No_argument "v"
		;
        applet_long_options = applet_longopts;

        The last member of struct option (val) typically is set to
        matching short option from applet_opts. If there is no matching
        char in applet_opts, then:
        - return bit have next position after short options
        - if has_arg is not "No_argument", use ptr for arg also
        - opt_complementary affects it 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 *opt_complementary

 ":"    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:

        opt_complementary = "abc";
        flags = getopt32(argv, "abcd")

        If getopt() finds "-a" on the command line, then
        getopt32's return value will be as if "-a -b -c" were
        found.

 "ww"   Adjacent double options have a counter associated which indicates
        the number of occurences of the option.
        For example the ps applet needs:
        if w is given once, GNU ps sets the width to 132,
        if w is given more than once, it is "unlimited"

        int w_counter = 0;
        opt_complementary = "ww";
        getopt32(argv, "w", &w_counter);
        if (w_counter)
                width = (w_counter == 1) ? 132 : INT_MAX;
        else
                get_terminal_width(...&width...);

        w_counter is a pointer to an integer. It has to be passed to
        getopt32() after all other option argument sinks.

        For example: accept multiple -v to indicate the level of verbosity
        and for each -b optarg, add optarg to my_b. Finally, if b is given,
        turn off c and vice versa:

        llist_t *my_b = NULL;
        int verbose_level = 0;
        opt_complementary = "vv:b::b-c:c-b";
        f = getopt32(argv, "vb:c", &my_b, &verbose_level);
        if (f & 2)       // -c after -b unsets -b flag
                while (my_b) { dosomething_with(my_b->data); my_b = my_b->link; }
        if (my_b)        // but llist is stored if -b is specified
                free_llist(my_b);
        if (verbose_level) printf("verbose level is %d\n", verbose_level);

Special characters:

 "-"    A dash as the first char in a opt_complementary group forces
        all arguments to be treated as options, even if they have
        no leading dashes. Next char in this case can't be a digit (0-9),
        use ':' or end of line. For example:

        opt_complementary = "-:w-x:x-w";
        getopt32(argv, "wx");

        Allows any arguments to be given without a dash (./program w x)
        as well as with a dash (./program -x).

 "--"   A double dash at the beginning of opt_complementary means the
        argv[1] string should always be treated as options, even if it isn't
        prefixed with a "-".  This is useful for special syntax in applets
        such as "ar" and "tar":
        tar xvf foo.tar

 "-N"   A dash as the first char in a opt_complementary group followed
        by a single digit (0-9) means that at least N non-option
        arguments must be present on the command line

 "=N"   An equal sign as the first char in a opt_complementary group followed
        by a single digit (0-9) means that exactly N non-option
        arguments must be present on the command line

 "?N"   A "?" as the first char in a opt_complementary group followed
        by a single digit (0-9) means that at most N arguments must be present
        on the command line.

 "V-"   An option with dash before colon or end-of-line results in
        bb_show_usage being called if this option is encountered.
        This is typically used to implement "print verbose usage message
        and exit" option.

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

        [FIXME: what if they are the same? like "x-x"? Is it ever useful?]

        For example:
        The du applet has the options "-s" and "-d depth".  If
        getopt32 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 opt_complementary = "s-d:d-s".  Only one flag value is
        added to getopt32'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;

        opt_complementary = "s-d:d-s:x-x";
        opt = getopt32(argv, "sd:x", &smax_print_depth);

        if (opt & 2)
                max_print_depth = atoi(smax_print_depth);
        if (opt & 4)
                printf("Detected odd -x usage\n");

 "a--b" A double dash 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 mutually exclusive and should raise an error
        if specified together.  In this case you must set
        opt_complementary = "b--cf:c--bf:f--bc".  If two of the
        mutually exclusive options are found, getopt32 will call
	bb_show_usage() and die.

 "x--x" Variation of the above, it means that -x option should occur
        at most once.

 "a::"  A double colon after a char in opt_complementary means that the
        option can occur multiple times. Each occurrence will be saved as
        a llist_t element instead of char*.

        For example:
        The grep applet can have one or more "-e pattern" arguments.
        In this case you should use getopt32() as follows:

        llist_t *patterns = NULL;

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

        opt_complementary = "e::";

        getopt32(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

 "a?b"  A "?" between an option and a group of options means that
        at least one of them is required to occur if the first option
        occurs in preceding command line arguments.

        For example from "id" applet:

        // Don't allow -n -r -rn -ug -rug -nug -rnug
        opt_complementary = "r?ug:n?ug:?u--g:g--u";
        flags = getopt32(argv, "rnug");

        This example allowed only:
        $ id; id -u; id -g; id -ru; id -nu; id -rg; id -ng; id -rnu; id -rng

 "X"    A opt_complementary group with just a single letter means
        that this option is required. If more than one such group exists,
        at least one option is required to occur (not all of them).
        For example from "start-stop-daemon" applet:

        // Don't allow -KS -SK, but -S or -K is required
        opt_complementary = "K:S:K--S:S--K";
        flags = getopt32(argv, "KS...);


        Don't forget to use ':'. For example, "?322-22-23X-x-a"
        is interpreted as "?3:22:-2:2-2:2-3Xa:2--x" -
        max 3 args; count uses of '-2'; min 2 args; if there is
        a '-2' option then unset '-3', '-X' and '-a'; if there is
        a '-2' and after it a '-x' then error out.
        But it's far too obfuscated. Use ':' to separate groups.
*/

/* Code here assumes that 'unsigned' is at least 32 bits wide */

const char *opt_complementary;

typedef struct {
	int opt;
	int list_flg;
	unsigned switch_on;
	unsigned switch_off;
	unsigned incongruously;
	unsigned requires;
	void **optarg;               /* char **optarg or llist_t **optarg */
	int *counter;
} t_complementary;

/* You can set applet_long_options for parse called long options */
#if ENABLE_GETOPT_LONG
static const struct option bb_null_long_options[1] = {
	{ 0, 0, 0, 0 }
};
const char *applet_long_options;
#endif

uint32_t option_mask32;

uint32_t
getopt32(char **argv, const char *applet_opts, ...)
{
	int argc;
	unsigned flags = 0;
	unsigned requires = 0;
	t_complementary complementary[33];
	int c;
	const unsigned char *s;
	t_complementary *on_off;
	va_list p;
#if ENABLE_GETOPT_LONG
	const struct option *l_o;
	struct option *long_options = (struct option *) &bb_null_long_options;
#endif
	unsigned trigger;
	char **pargv = NULL;
	int min_arg = 0;
	int max_arg = -1;

#define SHOW_USAGE_IF_ERROR     1
#define ALL_ARGV_IS_OPTS        2
#define FIRST_ARGV_IS_OPT       4
#define FREE_FIRST_ARGV_IS_OPT  8
	int spec_flgs = 0;

	argc = 0;
	while (argv[argc])
		argc++;

	va_start(p, applet_opts);

	c = 0;
	on_off = complementary;
	memset(on_off, 0, sizeof(complementary));

	/* skip GNU extension */
	s = (const unsigned char *)applet_opts;
	if (*s == '+' || *s == '-')
		s++;
	while (*s) {
		if (c >= 32) break;
		on_off->opt = *s;
		on_off->switch_on = (1 << c);
		if (*++s == ':') {
			on_off->optarg = va_arg(p, void **);
			while (*++s == ':') /* skip */;
		}
		on_off++;
		c++;
	}

#if ENABLE_GETOPT_LONG
	if (applet_long_options) {
		const char *optstr;
		unsigned i, count;

		count = 1;
		optstr = applet_long_options;
		while (optstr[0]) {
			optstr += strlen(optstr) + 3; /* skip NUL, has_arg, val */
			count++;
		}
		/* count == no. of longopts + 1 */
		long_options = alloca(count * sizeof(*long_options));
		memset(long_options, 0, count * sizeof(*long_options));
		i = 0;
		optstr = applet_long_options;
		while (--count) {
			long_options[i].name = optstr;
			optstr += strlen(optstr) + 1;
			long_options[i].has_arg = (unsigned char)(*optstr++);
			/* long_options[i].flag = NULL; */
			long_options[i].val = (unsigned char)(*optstr++);
			i++;
		}
		for (l_o = long_options; l_o->name; l_o++) {
			if (l_o->flag)
				continue;
			for (on_off = complementary; on_off->opt != 0; on_off++)
				if (on_off->opt == l_o->val)
					goto next_long;
			if (c >= 32) break;
			on_off->opt = l_o->val;
			on_off->switch_on = (1 << c);
			if (l_o->has_arg != no_argument)
				on_off->optarg = va_arg(p, void **);
			c++;
 next_long: ;
		}
	}
#endif /* ENABLE_GETOPT_LONG */
	for (s = (const unsigned char *)opt_complementary; s && *s; s++) {
		t_complementary *pair;
		unsigned *pair_switch;

		if (*s == ':')
			continue;
		c = s[1];
		if (*s == '?') {
			if (c < '0' || c > '9') {
				spec_flgs |= SHOW_USAGE_IF_ERROR;
			} else {
				max_arg = c - '0';
				s++;
			}
			continue;
		}
		if (*s == '-') {
			if (c < '0' || c > '9') {
				if (c == '-') {
					spec_flgs |= FIRST_ARGV_IS_OPT;
					s++;
				} else
					spec_flgs |= ALL_ARGV_IS_OPTS;
			} else {
				min_arg = c - '0';
				s++;
			}
			continue;
		}
		if (*s == '=') {
			min_arg = max_arg = c - '0';
			s++;
			continue;
		}
		for (on_off = complementary; on_off->opt; on_off++)
			if (on_off->opt == *s)
				break;
		if (c == ':' && s[2] == ':') {
			on_off->list_flg++;
			continue;
		}
		if (c == ':' || c == '\0') {
			requires |= on_off->switch_on;
			continue;
		}
		if (c == '-' && (s[2] == ':' || s[2] == '\0')) {
			flags |= on_off->switch_on;
			on_off->incongruously |= on_off->switch_on;
			s++;
			continue;
		}
		if (c == *s) {
			on_off->counter = va_arg(p, int *);
			s++;
		}
		pair = on_off;
		pair_switch = &(pair->switch_on);
		for (s++; *s && *s != ':'; s++) {
			if (*s == '?') {
				pair_switch = &(pair->requires);
			} else if (*s == '-') {
				if (pair_switch == &(pair->switch_off))
					pair_switch = &(pair->incongruously);
				else
					pair_switch = &(pair->switch_off);
			} else {
				for (on_off = complementary; on_off->opt; on_off++)
					if (on_off->opt == *s) {
						*pair_switch |= on_off->switch_on;
						break;
					}
			}
		}
		s--;
	}
	va_end(p);

	if (spec_flgs & FIRST_ARGV_IS_OPT) {
		if (argv[1] && argv[1][0] != '-' && argv[1][0] != '\0') {
			argv[1] = xasprintf("-%s", argv[1]);
			if (ENABLE_FEATURE_CLEAN_UP)
				spec_flgs |= FREE_FIRST_ARGV_IS_OPT;
		}
	}

	/* In case getopt32 was already called:
	 * reset the libc getopt() function, which keeps internal state.
	 *
	 * BSD-derived getopt() functions require that optind be set to 1 in
	 * order to reset getopt() state.  This used to be generally accepted
	 * way of resetting getopt().  However, glibc's getopt()
	 * has additional getopt() state beyond optind, and requires that
	 * optind be set to zero to reset its state.  So the unfortunate state of
	 * affairs is that BSD-derived versions of getopt() misbehave if
	 * optind is set to 0 in order to reset getopt(), and glibc's getopt()
	 * will core dump if optind is set 1 in order to reset getopt().
	 * 
	 * More modern versions of BSD require that optreset be set to 1 in
	 * order to reset getopt().   Sigh.  Standards, anyone?
	 */
#ifdef __GLIBC__
	optind = 0;
#else /* BSD style */
	optind = 1;
	/* optreset = 1; */
#endif
	/* optarg = NULL; opterr = 0; optopt = 0; - do we need this?? */

	/* Note: just "getopt() <= 0" will not work well for
	 * "fake" short options, like this one:
	 * wget $'-\203' "Test: test" http://kernel.org/
	 * (supposed to act as --header, but doesn't) */
#if ENABLE_GETOPT_LONG
	while ((c = getopt_long(argc, argv, applet_opts,
			long_options, NULL)) != -1) {
#else
	while ((c = getopt(argc, argv, applet_opts)) != -1) {
#endif
		c &= 0xff; /* fight libc's sign extension */
 loop_arg_is_opt:
		for (on_off = complementary; on_off->opt != c; on_off++) {
			/* c==0 if long opt have non NULL flag */
			if (on_off->opt == 0 && c != 0)
				bb_show_usage();
		}
		if (flags & on_off->incongruously)
			bb_show_usage();
		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->counter)
			(*(on_off->counter))++;
		if (on_off->list_flg) {
			llist_add_to_end((llist_t **)(on_off->optarg), optarg);
		} else if (on_off->optarg) {
			*(char **)(on_off->optarg) = optarg;
		}
		if (pargv != NULL)
			break;
	}

	if (spec_flgs & ALL_ARGV_IS_OPTS) {
		/* process argv is option, for example "ps" applet */
		if (pargv == NULL)
			pargv = argv + optind;
		while (*pargv) {
			c = **pargv;
			if (c == '\0') {
				pargv++;
			} else {
				(*pargv)++;
				goto loop_arg_is_opt;
			}
		}
	}

#if (ENABLE_AR || ENABLE_TAR) && ENABLE_FEATURE_CLEAN_UP
	if (spec_flgs & FREE_FIRST_ARGV_IS_OPT)
		free(argv[1]);
#endif
	/* check depending requires for given options */
	for (on_off = complementary; on_off->opt; on_off++) {
		if (on_off->requires && (flags & on_off->switch_on) &&
					(flags & on_off->requires) == 0)
			bb_show_usage();
	}
	if (requires && (flags & requires) == 0)
		bb_show_usage();
	argc -= optind;
	if (argc < min_arg || (max_arg >= 0 && argc > max_arg))
		bb_show_usage();

	option_mask32 = flags;
	return flags;
}