cmd/csh/sh.exp.c

/*
 * 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.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#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 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(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)
        error("%s", gettext(err));
    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