options.c

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Kenneth Almquist.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <signal.h>
#include <unistd.h>
#include <stdlib.h>

#include "shell.h"
#define DEFINE_OPTIONS
#include "options.h"
#undef DEFINE_OPTIONS
#include "nodes.h"	/* for other header files */
#include "eval.h"
#include "jobs.h"
#include "input.h"
#include "output.h"
#include "trap.h"
#include "var.h"
#include "memalloc.h"
#include "error.h"
#include "mystring.h"
#include "builtins.h"
#ifndef NO_HISTORY
#include "myhistedit.h"
#endif

char *arg0;			/* value of $0 */
struct shparam shellparam;	/* current positional parameters */
char **argptr;			/* argument list for builtin commands */
char *shoptarg;			/* set by nextopt (like getopt) */
char *nextopt_optptr;		/* used by nextopt */

char *minusc;			/* argument to -c option */


static int options(int);
static void minus_o(char *, int);
static void setoption(int, int);
static void setoptionbyindex(int, int);
static void setparam(int, char **);
static int getopts(char *, char *, char **, char ***, char **);


/*
 * Process the shell command line arguments.
 */

int
procargs(int argc, char **argv)
{
	int i, login;
	char *scriptname;

	argptr = argv;
	login = argptr[0] != NULL && argptr[0][0] == '-';
	if (argc > 0)
		argptr++;
	for (i = 0; i < NOPTS; i++)
		optval[i] = 2;
	privileged = (getuid() != geteuid() || getgid() != getegid());
	login |= options(1);
	if (*argptr == NULL && minusc == NULL)
		sflag = 1;
	if (iflag != 0 && sflag == 1 && isatty(0) && isatty(1)) {
		iflag = 1;
		if (Eflag == 2)
			Eflag = 1;
	}
	if (mflag == 2)
		mflag = iflag;
	for (i = 0; i < NOPTS; i++)
		if (optval[i] == 2)
			optval[i] = 0;
	arg0 = argv[0];
	if (sflag == 0 && minusc == NULL) {
		scriptname = *argptr++;
		setinputfile(scriptname, 0, -1 /* verify */);
		commandname = arg0 = scriptname;
	}
	/* POSIX 1003.2: first arg after -c cmd is $0, remainder $1... */
	if (argptr && minusc && *argptr)
		arg0 = *argptr++;

	shellparam.p = argptr;
	shellparam.reset = 1;
	/* assert(shellparam.malloc == 0 && shellparam.nparam == 0); */
	while (*argptr) {
		shellparam.nparam++;
		argptr++;
	}
	optschanged();

	return (login);
}


void
optschanged(void)
{
	setinteractive();
#ifndef NO_HISTORY
	histedit();
#endif
	setjobctl(mflag);
}

/*
 * Process shell options.  The global variable argptr contains a pointer
 * to the argument list; we advance it past the options.
 * If cmdline is true, process the shell's argv; otherwise, process arguments
 * to the set special builtin.
 */

static int
options(int cmdline)
{
	char *kp, *p;
	int val;
	int c;
	int login = 0;

	if (cmdline)
		minusc = NULL;
	while ((p = *argptr) != NULL) {
		argptr++;
		if ((c = *p++) == '-') {
			val = 1;
			/* A "-" or  "--" terminates options */
			if (p[0] == '\0')
				goto end_options1;
			if (p[0] == '-' && p[1] == '\0')
				goto end_options2;
			/**
			 * For the benefit of `#!' lines in shell scripts,
			 * treat a string of '-- *#.*' the same as '--'.
			 * This is needed so that a script starting with:
			 *	#!/bin/sh -- # -*- perl -*-
			 * will continue to work after a change is made to
			 * kern/imgact_shell.c to NOT token-ize the options
			 * specified on a '#!' line.  A bit of a kludge,
			 * but that trick is recommended in documentation
			 * for some scripting languages, and we might as
			 * well continue to support it.
			 */
			if (p[0] == '-') {
				kp = p + 1;
				while (*kp == ' ' || *kp == '\t')
					kp++;
				if (*kp == '#' || *kp == '\0')
					goto end_options2;
			}
		} else if (c == '+') {
			val = 0;
		} else {
			argptr--;
			break;
		}
		while ((c = *p++) != '\0') {
			if (c == 'c' && cmdline) {
				char *q;

				q = *argptr++;
				if (q == NULL || minusc != NULL)
					error("Bad -c option");
				minusc = q;
			} else if (c == 'l' && cmdline) {
				login = 1;
			} else if (c == 'o') {
				minus_o(*argptr, val);
				if (*argptr)
					argptr++;
			} else
				setoption(c, val);
		}
	}
	return (login);

	/* When processing `set', a single "-" means turn off -x and -v */
end_options1:
	if (!cmdline) {
		xflag = vflag = 0;
		return (login);
	}

	/*
	 * When processing `set', a "--" means the remaining arguments
	 * replace the positional parameters in the active shell.  If
	 * there are no remaining options, then all the positional
	 * parameters are cleared (equivalent to doing ``shift $#'').
	 */
end_options2:
	if (!cmdline) {
		if (*argptr == NULL)
			setparam(0, argptr);
		return (login);
	}

	/*
	 * At this point we are processing options given to 'sh' on a command
	 * line.  If an end-of-options marker ("-" or "--") is followed by an
	 * arg of "#", then skip over all remaining arguments.  Some scripting
	 * languages (e.g.: perl) document that /bin/sh will implement this
	 * behavior, and they recommend that users take advantage of it to
	 * solve certain issues that can come up when writing a perl script.
	 * Yes, this feature is in /bin/sh to help users write perl scripts.
	 */
	p = *argptr;
	if (p != NULL && p[0] == '#' && p[1] == '\0') {
		while (*argptr != NULL)
			argptr++;
		/* We need to keep the final argument */
		argptr--;
	}

	return (login);
}

static void
minus_o(char *name, int val)
{
	int i;
	const unsigned char *on;
	size_t len;

	if (name == NULL) {
		if (val) {
			/* "Pretty" output. */
			out1str("Current option settings\n");
			for (i = 0, on = optname; i < NOPTS; i++, on += *on + 1)
				out1fmt("%-16.*s%s\n", *on, on + 1,
					optval[i] ? "on" : "off");
		} else {
			/* Output suitable for re-input to shell. */
			for (i = 0, on = optname; i < NOPTS; i++, on += *on + 1)
				out1fmt("%s %co %.*s%s",
				    i % 6 == 0 ? "set" : "",
				    optval[i] ? '-' : '+',
				    *on, on + 1,
				    i % 6 == 5 || i == NOPTS - 1 ? "\n" : "");
		}
	} else {
		len = strlen(name);
		for (i = 0, on = optname; i < NOPTS; i++, on += *on + 1)
			if (*on == len && memcmp(on + 1, name, len) == 0) {
				setoptionbyindex(i, val);
				return;
			}
		error("Illegal option -o %s", name);
	}
}


static void
setoptionbyindex(int idx, int val)
{
	if (&optval[idx] == &privileged && !val && privileged) {
		if (setgid(getgid()) == -1)
			error("setgid");
		if (setuid(getuid()) == -1)
			error("setuid");
	}
	optval[idx] = val;
	if (val) {
		/* #%$ hack for ksh semantics */
		if (&optval[idx] == &Vflag)
			Eflag = 0;
		else if (&optval[idx] == &Eflag)
			Vflag = 0;
	}
}

static void
setoption(int flag, int val)
{
	int i;

	for (i = 0; i < NSHORTOPTS; i++)
		if (optletter[i] == flag) {
			setoptionbyindex(i, val);
			return;
		}
	error("Illegal option -%c", flag);
}


/*
 * Set the shell parameters.
 */

static void
setparam(int argc, char **argv)
{
	char **newparam;
	char **ap;

	ap = newparam = ckmalloc((argc + 1) * sizeof *ap);
	while (*argv) {
		*ap++ = savestr(*argv++);
	}
	*ap = NULL;
	freeparam(&shellparam);
	shellparam.malloc = 1;
	shellparam.nparam = argc;
	shellparam.p = newparam;
	shellparam.optp = NULL;
	shellparam.reset = 1;
	shellparam.optnext = NULL;
}


/*
 * Free the list of positional parameters.
 */

void
freeparam(struct shparam *param)
{
	char **ap;

	if (param->malloc) {
		for (ap = param->p ; *ap ; ap++)
			ckfree(*ap);
		ckfree(param->p);
	}
	if (param->optp) {
		for (ap = param->optp ; *ap ; ap++)
			ckfree(*ap);
		ckfree(param->optp);
	}
}



/*
 * The shift builtin command.
 */

int
shiftcmd(int argc, char **argv)
{
	int i, n;

	n = 1;
	if (argc > 1)
		n = number(argv[1]);
	if (n > shellparam.nparam)
		return 1;
	INTOFF;
	shellparam.nparam -= n;
	if (shellparam.malloc)
		for (i = 0; i < n; i++)
			ckfree(shellparam.p[i]);
	memmove(shellparam.p, shellparam.p + n,
	    (shellparam.nparam + 1) * sizeof(shellparam.p[0]));
	shellparam.reset = 1;
	INTON;
	return 0;
}



/*
 * The set builtin command.
 */

int
setcmd(int argc, char **argv)
{
	if (argc == 1)
		return showvarscmd(argc, argv);
	INTOFF;
	options(0);
	optschanged();
	if (*argptr != NULL) {
		setparam(argc - (argptr - argv), argptr);
	}
	INTON;
	return 0;
}


void
getoptsreset(const char *value)
{
	while (*value == '0')
		value++;
	if (strcmp(value, "1") == 0)
		shellparam.reset = 1;
}

/*
 * The getopts builtin.  Shellparam.optnext points to the next argument
 * to be processed.  Shellparam.optptr points to the next character to
 * be processed in the current argument.  If shellparam.optnext is NULL,
 * then it's the first time getopts has been called.
 */

int
getoptscmd(int argc, char **argv)
{
	char **optbase = NULL, **ap;
	int i;

	if (argc < 3)
		error("usage: getopts optstring var [arg]");

	if (shellparam.reset == 1) {
		INTOFF;
		if (shellparam.optp) {
			for (ap = shellparam.optp ; *ap ; ap++)
				ckfree(*ap);
			ckfree(shellparam.optp);
			shellparam.optp = NULL;
		}
		if (argc > 3) {
			shellparam.optp = ckmalloc((argc - 2) * sizeof *ap);
			memset(shellparam.optp, '\0', (argc - 2) * sizeof *ap);
			for (i = 0; i < argc - 3; i++)
				shellparam.optp[i] = savestr(argv[i + 3]);
		}
		INTON;
		optbase = argc == 3 ? shellparam.p : shellparam.optp;
		shellparam.optnext = optbase;
		shellparam.optptr = NULL;
		shellparam.reset = 0;
	} else
		optbase = shellparam.optp ? shellparam.optp : shellparam.p;

	return getopts(argv[1], argv[2], optbase, &shellparam.optnext,
		       &shellparam.optptr);
}

static int
getopts(char *optstr, char *optvar, char **optfirst, char ***optnext,
    char **optptr)
{
	char *p, *q;
	char c = '?';
	int done = 0;
	int ind = 0;
	int err = 0;
	char s[10];
	const char *newoptarg = NULL;

	if ((p = *optptr) == NULL || *p == '\0') {
		/* Current word is done, advance */
		if (*optnext == NULL)
			return 1;
		p = **optnext;
		if (p == NULL || *p != '-' || *++p == '\0') {
atend:
			ind = *optnext - optfirst + 1;
			*optnext = NULL;
			p = NULL;
			done = 1;
			goto out;
		}
		(*optnext)++;
		if (p[0] == '-' && p[1] == '\0')	/* check for "--" */
			goto atend;
	}

	c = *p++;
	for (q = optstr; *q != c; ) {
		if (*q == '\0') {
			if (optstr[0] == ':') {
				s[0] = c;
				s[1] = '\0';
				newoptarg = s;
			}
			else
				out2fmt_flush("Illegal option -%c\n", c);
			c = '?';
			goto out;
		}
		if (*++q == ':')
			q++;
	}

	if (*++q == ':') {
		if (*p == '\0' && (p = **optnext) == NULL) {
			if (optstr[0] == ':') {
				s[0] = c;
				s[1] = '\0';
				newoptarg = s;
				c = ':';
			}
			else {
				out2fmt_flush("No arg for -%c option\n", c);
				c = '?';
			}
			goto out;
		}

		if (p == **optnext)
			(*optnext)++;
		newoptarg = p;
		p = NULL;
	}

out:
	if (*optnext != NULL)
		ind = *optnext - optfirst + 1;
	*optptr = p;
	if (newoptarg != NULL)
		err |= setvarsafe("OPTARG", newoptarg, 0);
	else {
		INTOFF;
		err |= unsetvar("OPTARG");
		INTON;
	}
	fmtstr(s, sizeof(s), "%d", ind);
	err |= setvarsafe("OPTIND", s, VNOFUNC);
	s[0] = c;
	s[1] = '\0';
	err |= setvarsafe(optvar, s, 0);
	if (err) {
		*optnext = NULL;
		*optptr = NULL;
		flushall();
		exraise(EXERROR);
	}
	return done;
}

/*
 * Standard option processing (a la getopt) for builtin routines.  The
 * only argument that is passed to nextopt is the option string; the
 * other arguments are unnecessary.  It returns the option, or '\0' on
 * end of input.
 */

int
nextopt(const char *optstring)
{
	char *p;
	const char *q;
	char c;

	if ((p = nextopt_optptr) == NULL || *p == '\0') {
		p = *argptr;
		if (p == NULL || *p != '-' || *++p == '\0')
			return '\0';
		argptr++;
		if (p[0] == '-' && p[1] == '\0')	/* check for "--" */
			return '\0';
	}
	c = *p++;
	for (q = optstring ; *q != c ; ) {
		if (*q == '\0')
			error("Illegal option -%c", c);
		if (*++q == ':')
			q++;
	}
	if (*++q == ':') {
		if (*p == '\0' && (p = *argptr++) == NULL)
			error("No arg for -%c option", c);
		shoptarg = p;
		p = NULL;
	}
	if (p != NULL && *p != '\0')
		nextopt_optptr = p;
	else
		nextopt_optptr = NULL;
	return c;
}