/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
/*	  All Rights Reserved  	*/

/*
 * Copyright (c) 1980 Regents of the University of California.
 * All rights reserved.  The Berkeley Software License Agreement
 * specifies the terms and conditions for redistribution.
 */

#include "sh.h"
#include "sh.tconst.h"

/*
 * C shell
 */

#define	IGNORE	1	/* in ignore, it means to ignore value, just parse */
#define	NOGLOB	2	/* in ignore, it means not to globone */

#define	ADDOP	1
#define	MULOP	2
#define	EQOP	4
#define	RELOP	8
#define	RESTOP	16
#define	ANYOP	31

#define	EQEQ	1
#define	GTR	2
#define	LSS	4
#define	NOTEQ	6
#define	EQMATCH 7
#define	NOTEQMATCH 8

int	uid;

int	exp0(tchar ***, bool);
int	exp1(tchar ***, bool);
int	exp2(tchar ***, bool);
int	exp2a(tchar ***, bool);
int	exp2b(tchar ***, bool);
int	exp2c(tchar ***, bool);
tchar	*exp3(tchar ***, bool);
tchar	*exp3a(tchar ***, bool);
tchar	*exp4(tchar ***, bool);
tchar	*exp5(tchar ***, bool);
tchar	*exp6(tchar ***, bool);
void	evalav(tchar **);

/*
 * Determine if file given by name is accessible with permissions
 * given by mode.
 *
 * Borrowed from the Bourne sh, and modified a bit
 *
 * If the requested access  is  permitted,  a  value  of  0  is
 * returned.  Otherwise, a value of -1 is returned and errno is
 * set to indicate the error
 */

int
chk_access(tchar *path, mode_t mode)
{
	static int flag;
	static uid_t euid;
	struct stat statb;
	mode_t ftype;
	unsigned char name[MAXPATHLEN*MB_LEN_MAX]; /* General use buffer. */

	/* convert tchar * to char * */
	tstostr((char *)name, path);

	if (flag == 0) {
		euid = geteuid();
		flag = 1;
	}
	if (stat((char *)name, &statb) == 0) {
		ftype = statb.st_mode & S_IFMT;
		if (access((char *)name, 010|(mode>>6)) == 0) {
			if (euid == 0) {
				if (ftype != S_IFREG || mode != S_IEXEC)
					return (0);
				/* root can execute file as long as it has execute
				permission for someone */
				if (statb.st_mode & (S_IEXEC|(S_IEXEC>>3)|(S_IEXEC>>6)))
					return (0);
				return (-1);
			}
			return (0);
		}
	}
	return (-1);
}

int
exp(tchar ***vp)
{
#ifdef TRACE
	tprintf("TRACE- exp()\n");
#endif

	return (exp0(vp, 0));
}

int
exp0(tchar ***vp, bool ignore)
{
	int p1 = exp1(vp, ignore);
#ifdef TRACE
	tprintf("TRACE- exp0()\n");
#endif

#ifdef EDEBUG
	etraci("exp0 p1", p1, vp);
#endif
	if (**vp && eq(**vp, S_BARBAR /* "||" */)) {
		int p2;

		(*vp)++;
		p2 = exp0(vp, (ignore&IGNORE) || p1);
#ifdef EDEBUG
		etraci("exp0 p2", p2, vp);
#endif
		return (p1 || p2);
	}
	return (p1);
}

int
exp1(tchar ***vp, bool ignore)
{
	int p1 = exp2(vp, ignore);

#ifdef TRACE
	tprintf("TRACE- exp1()\n");
#endif
#ifdef EDEBUG
	etraci("exp1 p1", p1, vp);
#endif
	if (**vp && eq(**vp, S_ANDAND /* "&&" */)) {
		int p2;

		(*vp)++;
		p2 = exp1(vp, (ignore&IGNORE) || !p1);
#ifdef EDEBUG
		etraci("exp1 p2", p2, vp);
#endif
		return (p1 && p2);
	}
	return (p1);
}

int
exp2(tchar ***vp, bool ignore)
{
	int p1 = exp2a(vp, ignore);

#ifdef TRACE
	tprintf("TRACE- exp2()\n");
#endif
#ifdef EDEBUG
	etraci("exp3 p1", p1, vp);
#endif
	if (**vp && eq(**vp, S_BAR /* "|" */)) {
		int p2;

		(*vp)++;
		p2 = exp2(vp, ignore);
#ifdef EDEBUG
		etraci("exp3 p2", p2, vp);
#endif
		return (p1 | p2);
	}
	return (p1);
}

int
exp2a(tchar ***vp, bool ignore)
{
	int p1 = exp2b(vp, ignore);

#ifdef TRACE
	tprintf("TRACE- exp2a()\n");
#endif
#ifdef EDEBUG
	etraci("exp2a p1", p1, vp);
#endif
	if (**vp && eq(**vp, S_HAT /* "^" */)) {
		int p2;

		(*vp)++;
		p2 = exp2a(vp, ignore);
#ifdef EDEBUG
		etraci("exp2a p2", p2, vp);
#endif
		return (p1 ^ p2);
	}
	return (p1);
}

int
exp2b(tchar ***vp, bool ignore)
{
	int p1 = exp2c(vp, ignore);

#ifdef TRACE
	tprintf("TRACE- exp2b()\n");
#endif
#ifdef EDEBUG
	etraci("exp2b p1", p1, vp);
#endif
	if (**vp && eq(**vp, S_AND /* "&" */)) {
		int p2;

		(*vp)++;
		p2 = exp2b(vp, ignore);
#ifdef EDEBUG
		etraci("exp2b p2", p2, vp);
#endif
		return (p1 & p2);
	}
	return (p1);
}

int
exp2c(tchar ***vp, bool ignore)
{
	tchar *p1 = exp3(vp, ignore);
	tchar *p2;
	int i;

#ifdef TRACE
	tprintf("TRACE- exp2c()\n");
#endif
#ifdef EDEBUG
	etracc("exp2c p1", p1, vp);
#endif
	if (i = isa(**vp, EQOP)) {
		(*vp)++;
		if (i == EQMATCH || i == NOTEQMATCH)
			ignore |= NOGLOB;
		p2 = exp3(vp, ignore);
#ifdef EDEBUG
		etracc("exp2c p2", p2, vp);
#endif
		if (!(ignore&IGNORE)) switch (i) {

		case EQEQ:
			i = eq(p1, p2);
			break;

		case NOTEQ:
			i = !eq(p1, p2);
			break;

		case EQMATCH:
			i = Gmatch(p1, p2);
			break;

		case NOTEQMATCH:
			i = !Gmatch(p1, p2);
			break;
		}
		xfree(p1), xfree(p2);
		return (i);
	}
	i = egetn(p1);
	xfree(p1);
	return (i);
}

tchar *
exp3(tchar ***vp, bool ignore)
{
	tchar *p1, *p2;
	int i;

#ifdef TRACE
	tprintf("TRACE- exp3()\n");
#endif
	p1 = exp3a(vp, ignore);
#ifdef EDEBUG
	etracc("exp3 p1", p1, vp);
#endif
	if (i = isa(**vp, RELOP)) {
		(*vp)++;
		if (**vp && eq(**vp, S_EQ /* "=" */))
			i |= 1, (*vp)++;
		p2 = exp3(vp, ignore);
#ifdef EDEBUG
		etracc("exp3 p2", p2, vp);
#endif
		if (!(ignore&IGNORE)) switch (i) {

		case GTR:
			i = egetn(p1) > egetn(p2);
			break;

		case GTR|1:
			i = egetn(p1) >= egetn(p2);
			break;

		case LSS:
			i = egetn(p1) < egetn(p2);
			break;

		case LSS|1:
			i = egetn(p1) <= egetn(p2);
			break;
		}
		xfree(p1), xfree(p2);
		return (putn(i));
	}
	return (p1);
}

tchar *
exp3a(tchar ***vp, bool ignore)
{
	tchar *p1, *p2, *op;
	int i;

#ifdef TRACE
	tprintf("TRACE- exp3a()\n");
#endif
	p1 = exp4(vp, ignore);
#ifdef EDEBUG
	etracc("exp3a p1", p1, vp);
#endif
	op = **vp;
	/* if (op && any(op[0], "<>") && op[0] == op[1]) { */
	if (op && (op[0] == '<' || op[0] == '>') && op[0] == op[1]) {
		(*vp)++;
		p2 = exp3a(vp, ignore);
#ifdef EDEBUG
		etracc("exp3a p2", p2, vp);
#endif
		if (op[0] == '<')
			i = egetn(p1) << egetn(p2);
		else
			i = egetn(p1) >> egetn(p2);
		xfree(p1), xfree(p2);
		return (putn(i));
	}
	return (p1);
}

tchar *
exp4(tchar ***vp, bool ignore)
{
	tchar *p1, *p2;
	int i = 0;

#ifdef TRACE
	tprintf("TRACE- exp4()\n");
#endif
	p1 = exp5(vp, ignore);
#ifdef EDEBUG
	etracc("exp4 p1", p1, vp);
#endif
	if (isa(**vp, ADDOP)) {
		tchar *op = *(*vp)++;

		p2 = exp4(vp, ignore);
#ifdef EDEBUG
		etracc("exp4 p2", p2, vp);
#endif
		if (!(ignore&IGNORE)) switch (op[0]) {

		case '+':
			i = egetn(p1) + egetn(p2);
			break;

		case '-':
			i = egetn(p1) - egetn(p2);
			break;
		}
		xfree(p1), xfree(p2);
		return (putn(i));
	}
	return (p1);
}

tchar *
exp5(tchar ***vp, bool ignore)
{
	tchar *p1, *p2;
	int i = 0;

#ifdef TRACE
	tprintf("TRACE- exp5()\n");
#endif
	p1 = exp6(vp, ignore);
#ifdef EDEBUG
	etracc("exp5 p1", p1, vp);
#endif
	if (isa(**vp, MULOP)) {
		tchar *op = *(*vp)++;

		p2 = exp5(vp, ignore);
#ifdef EDEBUG
		etracc("exp5 p2", p2, vp);
#endif
		if (!(ignore&IGNORE)) switch (op[0]) {

		case '*':
			i = egetn(p1) * egetn(p2);
			break;

		case '/':
			i = egetn(p2);
			if (i == 0)
				error("Divide by 0");
			i = egetn(p1) / i;
			break;

		case '%':
			i = egetn(p2);
			if (i == 0)
				error("Mod by 0");
			i = egetn(p1) % i;
			break;
		}
		xfree(p1), xfree(p2);
		return (putn(i));
	}
	return (p1);
}

tchar *
exp6(tchar ***vp, bool ignore)
{
	int ccode, i;
	tchar *cp, *dp, *ep;

#ifdef TRACE
	tprintf("TRACE- exp6()\n");
#endif
	if (**vp == 0)
		bferr("Expression syntax");
	if (eq(**vp, S_EXAS /* "!" */)) {
		(*vp)++;
		cp = exp6(vp, ignore);
#ifdef EDEBUG
		etracc("exp6 ! cp", cp, vp);
#endif
		i = egetn(cp);
		xfree(cp);
		return (putn(!i));
	}
	if (eq(**vp, S_TIL /* "~" */)) {
		(*vp)++;
		cp = exp6(vp, ignore);
#ifdef EDEBUG
		etracc("exp6 ~ cp", cp, vp);
#endif
		i = egetn(cp);
		xfree(cp);
		return (putn(~i));
	}
	if (eq(**vp, S_LPAR /* "(" */)) {
		(*vp)++;
		ccode = exp0(vp, ignore);
#ifdef EDEBUG
		etraci("exp6 () ccode", ccode, vp);
#endif
		if (*vp == 0 || **vp == 0 || ***vp != ')')
			bferr("Expression syntax");
		(*vp)++;
		return (putn(ccode));
	}
	if (eq(**vp, S_LBRA /* "{" */)) {
		tchar **v;
		struct command faket;
		tchar *fakecom[2];

		faket.t_dtyp = TCOM;
		faket.t_dflg = 0;
		faket.t_dcar = faket.t_dcdr = faket.t_dspr = (struct command *)0;
		faket.t_dcom = fakecom;
		fakecom[0] = S_BRAPPPBRA /* "{ ... }" */;
		fakecom[1] = NOSTR;
		(*vp)++;
		v = *vp;
		for (;;) {
			if (!**vp)
				bferr("Missing }");
			if (eq(*(*vp)++, S_RBRA /* "}" */))
				break;
		}
		if (ignore&IGNORE)
			return (S_ /* "" */);
		psavejob();
		if (pfork(&faket, -1) == 0) {
			*--(*vp) = 0;
			evalav(v);
			exitstat();
		}
		pwait();
		prestjob();
#ifdef EDEBUG
		etraci("exp6 {} status", egetn(value("status")), vp);
#endif
		return (putn(egetn(value(S_status /* "status" */)) == 0));
	}
	if (isa(**vp, ANYOP))
		return (S_ /* "" */);
	cp = *(*vp)++;
	if (*cp == '-' && any(cp[1], S_erwxfdzo /* "erwxfdzo" */)) {
		struct stat stb;

		if (cp[2] != '\0')
			bferr("Malformed file inquiry");

		/*
		 * Detect missing file names by checking for operator
		 * in the file name position.  However, if an operator
		 * name appears there, we must make sure that there's
		 * no file by that name (e.g., "/") before announcing
		 * an error.  Even this check isn't quite right, since
		 * it doesn't take globbing into account.
		 */
		if ((**vp == NULL) || isa(**vp, ANYOP) && stat_(**vp, &stb))
			bferr("Missing file name");
		dp = *(*vp)++;

		if (ignore&IGNORE)
			return (S_ /* "" */);
		ep = globone(dp);
		switch (cp[1]) {

		case 'r':
			i = !chk_access(ep, S_IREAD);
			break;

		case 'w':
			i = !chk_access(ep, S_IWRITE);
			break;

		case 'x':
			i = !chk_access(ep, S_IEXEC);
			break;

		default:
			if (stat_(ep, &stb)) {
				xfree(ep);
				return (S_0 /* "0" */);
			}
			switch (cp[1]) {

			case 'f':
				i = (stb.st_mode & S_IFMT) == S_IFREG;
				break;

			case 'd':
				i = (stb.st_mode & S_IFMT) == S_IFDIR;
				break;

			case 'z':
				i = stb.st_size == 0;
				break;

			case 'e':
				i = 1;
				break;

			case 'o':
				i = stb.st_uid == uid;
				break;
			}
		}
#ifdef EDEBUG
		etraci("exp6 -? i", i, vp);
#endif
		xfree(ep);
		return (putn(i));
	}
#ifdef EDEBUG
	etracc("exp6 default", cp, vp);
#endif
	return (ignore&NOGLOB ? savestr(cp) : globone(cp));
}

void
evalav(tchar **v)
{
	struct wordent paraml;
	struct wordent *hp = &paraml;
	struct command *t;
	struct wordent *wdp = hp;

#ifdef TRACE
	tprintf("TRACE- evalav()\n");
#endif
	set(S_status /* "status" */, S_0 /* "0" */);
	hp->prev = hp->next = hp;
	hp->word = S_ /* "" */;
	while (*v) {
		struct wordent *new = (struct wordent *)xcalloc(1, sizeof *wdp);

		new->prev = wdp;
		new->next = hp;
		wdp->next = new;
		wdp = new;
		wdp->word = savestr(*v++);
	}
	hp->prev = wdp;
	alias(&paraml);
	t = syntax(paraml.next, &paraml, 0);
	if (err_msg)
		error("%s", gettext(err_msg));
	execute(t, -1);
	freelex(&paraml), freesyn(t);
}

int
isa(tchar *cp, int what)
{

#ifdef TRACE
	tprintf("TRACE- isa()\n");
#endif
	if (cp == 0)
		return ((what & RESTOP) != 0);
	if (cp[1] == 0) {
		if (what & ADDOP && (*cp == '+' || *cp == '-'))
			return (1);
		if (what & MULOP && (*cp == '*' || *cp == '/' || *cp == '%'))
			return (1);
		if (what & RESTOP && (*cp == '(' || *cp == ')' || *cp == '!' ||
					*cp == '~' || *cp == '^' || *cp == '"'))
			return (1);
	} else if (cp[2] == 0) {
		if (what & RESTOP) {
			if (cp[0] == '|' && cp[1] == '&')
				return (1);
			if (cp[0] == '<' && cp[1] == '<')
				return (1);
			if (cp[0] == '>' && cp[1] == '>')
				return (1);
		}
		if (what & EQOP) {
			if (cp[0] == '=') {
				if (cp[1] == '=')
					return (EQEQ);
				if (cp[1] == '~')
					return (EQMATCH);
			} else if (cp[0] == '!') {
				if (cp[1] == '=')
					return (NOTEQ);
				if (cp[1] == '~')
					return (NOTEQMATCH);
			}
		}
	}
	if (what & RELOP) {
		if (*cp == '<')
			return (LSS);
		if (*cp == '>')
			return (GTR);
	}
	return (0);
}

int
egetn(tchar *cp)
{

#ifdef TRACE
	tprintf("TRACE- egetn()\n");
#endif
	if (*cp && *cp != '-' && !digit(*cp))
		bferr("Expression syntax");
	return (getn(cp));
}

/* Phew! */

#ifdef EDEBUG
void
etraci(tchar *str, int i, tchar ***vp)
{

	printf("%s=%d\t", str, i);
	blkpr(*vp);
	printf("\n");
}

void
etracc(tchar *str, tchar *cp, tchar ***vp)
{

	printf("%s=%s\t", str, cp);
	blkpr(*vp);
	printf("\n");
}
#endif