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sh.parse.c

/* $Header: /src/pub/tcsh/sh.parse.c,v 3.11 2002/03/08 17:36:46 christos Exp $ */
/*
 * sh.parse.c: Interpret a list of tokens
 */
/*-
 * Copyright (c) 1980, 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * 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 "sh.h"

RCSID("$Id: sh.parse.c,v 3.11 2002/03/08 17:36:46 christos Exp $")

/*
 * C shell
 */
static      void         asyntax __P((struct wordent *, struct wordent *));
static      void         asyn0       __P((struct wordent *, struct wordent *));
static      void         asyn3       __P((struct wordent *, struct wordent *));
static      struct wordent    *freenod __P((struct wordent *, struct wordent *));
static      struct command    *syn0  __P((struct wordent *, struct wordent *, int));
static      struct command    *syn1  __P((struct wordent *, struct wordent *, int));
static      struct command    *syn1a       __P((struct wordent *, struct wordent *, int));
static      struct command    *syn1b       __P((struct wordent *, struct wordent *, int));
static      struct command    *syn2  __P((struct wordent *, struct wordent *, int));
static      struct command    *syn3  __P((struct wordent *, struct wordent *, int));

#define ALEFT     51          /* max of 50 alias expansions  */
#define HLEFT     11          /* max of 10 history expansions */
/*
 * Perform aliasing on the word list lexp
 * Do a (very rudimentary) parse to separate into commands.
 * If word 0 of a command has an alias, do it.
 * Repeat a maximum of 50 times.
 */
static int aleft;
extern int hleft;
void
alias(lexp)
    register struct wordent *lexp;
{
    jmp_buf_t osetexit;

    aleft = ALEFT;
    hleft = HLEFT;
    getexit(osetexit);
    (void) setexit();
    if (haderr) {
      resexit(osetexit);
      reset();
    }
    if (--aleft == 0)
      stderror(ERR_ALIASLOOP);
    asyntax(lexp->next, lexp);
    resexit(osetexit);
}

static void
asyntax(p1, p2)
    register struct wordent *p1, *p2;
{
    while (p1 != p2)
      if (any(";&\n", p1->word[0]))
          p1 = p1->next;
      else {
          asyn0(p1, p2);
          return;
      }
}

static void
asyn0(p1, p2)
    struct wordent *p1;
    register struct wordent *p2;
{
    register struct wordent *p;
    register int l = 0;

    for (p = p1; p != p2; p = p->next)
      switch (p->word[0]) {

      case '(':
          l++;
          continue;

      case ')':
          l--;
          if (l < 0)
            stderror(ERR_TOOMANYRP);
          continue;

      case '>':
          if (p->next != p2 && eq(p->next->word, STRand))
            p = p->next;
          continue;

      case '&':
      case '|':
      case ';':
      case '\n':
          if (l != 0)
            continue;
          asyn3(p1, p);
          asyntax(p->next, p2);
          return;

      default:
          break;
      }
    if (l == 0)
      asyn3(p1, p2);
}

static void
asyn3(p1, p2)
    struct wordent *p1;
    register struct wordent *p2;
{
    register struct varent *ap;
    struct wordent alout;
    register bool redid;

    if (p1 == p2)
      return;
    if (p1->word[0] == '(') {
      for (p2 = p2->prev; p2->word[0] != ')'; p2 = p2->prev)
          if (p2 == p1)
            return;
      if (p2 == p1->next)
          return;
      asyn0(p1->next, p2);
      return;
    }
    ap = adrof1(p1->word, &aliases);
    if (ap == 0)
      return;
    alhistp = p1->prev;
    alhistt = p2;
    alvec = ap->vec;
    redid = lex(&alout);
    alhistp = alhistt = 0;
    alvec = 0;
    if (seterr) {
      freelex(&alout);
      stderror(ERR_OLD);
    }
    if (p1->word[0] && eq(p1->word, alout.next->word)) {
      Char   *cp = alout.next->word;

      alout.next->word = Strspl(STRQNULL, cp);
      xfree((ptr_t) cp);
    }
    p1 = freenod(p1, redid ? p2 : p1->next);
    if (alout.next != &alout) {
      p1->next->prev = alout.prev->prev;
      alout.prev->prev->next = p1->next;
      alout.next->prev = p1;
      p1->next = alout.next;
      xfree((ptr_t) alout.prev->word);
      xfree((ptr_t) (alout.prev));
    }
    reset();                  /* throw! */
}

static struct wordent *
freenod(p1, p2)
    register struct wordent *p1, *p2;
{
    register struct wordent *retp = p1->prev;

    while (p1 != p2) {
      xfree((ptr_t) p1->word);
      p1 = p1->next;
      xfree((ptr_t) (p1->prev));
    }
    retp->next = p2;
    p2->prev = retp;
    return (retp);
}

#define     P_HERE      1
#define     P_IN  2
#define     P_OUT 4
#define     P_DIAG      8

/*
 * syntax
 *    empty
 *    syn0
 */
struct command *
syntax(p1, p2, flags)
    register struct wordent *p1, *p2;
    int     flags;
{

    while (p1 != p2)
      if (any(";&\n", p1->word[0]))
          p1 = p1->next;
      else
          return (syn0(p1, p2, flags));
    return (0);
}

/*
 * syn0
 *    syn1
 *    syn1 & syntax
 */
static struct command *
syn0(p1, p2, flags)
    struct wordent *p1, *p2;
    int     flags;
{
    register struct wordent *p;
    register struct command *t, *t1;
    int     l;

    l = 0;
    for (p = p1; p != p2; p = p->next)
      switch (p->word[0]) {

      case '(':
          l++;
          continue;

      case ')':
          l--;
          if (l < 0)
            seterror(ERR_TOOMANYRP);
          continue;

      case '|':
          if (p->word[1] == '|')
            continue;
          /*FALLTHROUGH*/

      case '>':
          if (p->next != p2 && eq(p->next->word, STRand))
            p = p->next;
          continue;

      case '&':
          if (l != 0)
            break;
          if (p->word[1] == '&')
            continue;
          t1 = syn1(p1, p, flags);
          if (t1->t_dtyp == NODE_LIST ||
            t1->t_dtyp == NODE_AND ||
            t1->t_dtyp == NODE_OR) {
            t = (struct command *) xcalloc(1, sizeof(*t));
            t->t_dtyp = NODE_PAREN;
            t->t_dflg = F_AMPERSAND | F_NOINTERRUPT;
            t->t_dspr = t1;
            t1 = t;
          }
          else
            t1->t_dflg |= F_AMPERSAND | F_NOINTERRUPT;
          t = (struct command *) xcalloc(1, sizeof(*t));
          t->t_dtyp = NODE_LIST;
          t->t_dflg = 0;
          t->t_dcar = t1;
          t->t_dcdr = syntax(p, p2, flags);
          return (t);
      default:
          break;
      }
    if (l == 0)
      return (syn1(p1, p2, flags));
    seterror(ERR_TOOMANYLP);
    return (0);
}

/*
 * syn1
 *    syn1a
 *    syn1a ; syntax
 */
static struct command *
syn1(p1, p2, flags)
    struct wordent *p1, *p2;
    int     flags;
{
    register struct wordent *p;
    register struct command *t;
    int     l;

    l = 0;
    for (p = p1; p != p2; p = p->next)
      switch (p->word[0]) {

      case '(':
          l++;
          continue;

      case ')':
          l--;
          continue;

      case ';':
      case '\n':
          if (l != 0)
            break;
          t = (struct command *) xcalloc(1, sizeof(*t));
          t->t_dtyp = NODE_LIST;
          t->t_dcar = syn1a(p1, p, flags);
          t->t_dcdr = syntax(p->next, p2, flags);
          if (t->t_dcdr == 0)
            t->t_dcdr = t->t_dcar, t->t_dcar = 0;
          return (t);

      default:
          break;
      }
    return (syn1a(p1, p2, flags));
}

/*
 * syn1a
 *    syn1b
 *    syn1b || syn1a
 */
static struct command *
syn1a(p1, p2, flags)
    struct wordent *p1, *p2;
    int     flags;
{
    register struct wordent *p;
    register struct command *t;
    register int l = 0;

    for (p = p1; p != p2; p = p->next)
      switch (p->word[0]) {

      case '(':
          l++;
          continue;

      case ')':
          l--;
          continue;

      case '|':
          if (p->word[1] != '|')
            continue;
          if (l == 0) {
            t = (struct command *) xcalloc(1, sizeof(*t));
            t->t_dtyp = NODE_OR;
            t->t_dcar = syn1b(p1, p, flags);
            t->t_dcdr = syn1a(p->next, p2, flags);
            t->t_dflg = 0;
            return (t);
          }
          continue;

      default:
          break;
      }
    return (syn1b(p1, p2, flags));
}

/*
 * syn1b
 *    syn2
 *    syn2 && syn1b
 */
static struct command *
syn1b(p1, p2, flags)
    struct wordent *p1, *p2;
    int     flags;
{
    register struct wordent *p;
    register struct command *t;
    register int l = 0;

    for (p = p1; p != p2; p = p->next)
      switch (p->word[0]) {

      case '(':
          l++;
          continue;

      case ')':
          l--;
          continue;

      case '&':
          if (p->word[1] == '&' && l == 0) {
            t = (struct command *) xcalloc(1, sizeof(*t));
            t->t_dtyp = NODE_AND;
            t->t_dcar = syn2(p1, p, flags);
            t->t_dcdr = syn1b(p->next, p2, flags);
            t->t_dflg = 0;
            return (t);
          }
          continue;

      default:
          break;
      }
    return (syn2(p1, p2, flags));
}

/*
 * syn2
 *    syn3
 *    syn3 | syn2
 *    syn3 |& syn2
 */
static struct command *
syn2(p1, p2, flags)
    struct wordent *p1, *p2;
    int     flags;
{
    register struct wordent *p, *pn;
    register struct command *t;
    register int l = 0;
    int     f;

    for (p = p1; p != p2; p = p->next)
      switch (p->word[0]) {

      case '(':
          l++;
          continue;

      case ')':
          l--;
          continue;

      case '|':
          if (l != 0)
            continue;
          t = (struct command *) xcalloc(1, sizeof(*t));
          f = flags | P_OUT;
          pn = p->next;
          if (pn != p2 && pn->word[0] == '&') {
            f |= P_DIAG;
            t->t_dflg |= F_STDERR;
          }
          t->t_dtyp = NODE_PIPE;
          t->t_dcar = syn3(p1, p, f);
          if (pn != p2 && pn->word[0] == '&')
            p = pn;
          t->t_dcdr = syn2(p->next, p2, flags | P_IN);
          return (t);

      default:
          break;
      }
    return (syn3(p1, p2, flags));
}

static char RELPAR[] = {'<', '>', '(', ')', '\0'};

/*
 * syn3
 *    ( syn0 ) [ < in  ] [ > out ]
 *    word word* [ < in ] [ > out ]
 *    KEYWORD ( word* ) word* [ < in ] [ > out ]
 *
 *    KEYWORD = (@ exit foreach if set switch test while)
 */
static struct command *
syn3(p1, p2, flags)
    struct wordent *p1, *p2;
    int     flags;
{
    register struct wordent *p;
    struct wordent *lp, *rp;
    register struct command *t;
    register int l;
    Char  **av;
    int     n, c;
    bool    specp = 0;

    if (p1 != p2) {
      p = p1;
again:
      switch (srchx(p->word)) {

      case TC_ELSE:
          p = p->next;
          if (p != p2)
            goto again;
          break;

      case TC_EXIT:
      case TC_FOREACH:
      case TC_IF:
      case TC_LET:
      case TC_SET:
      case TC_SWITCH:
      case TC_WHILE:
          specp = 1;
          break;
      default:
          break;
      }
    }
    n = 0;
    l = 0;
    for (p = p1; p != p2; p = p->next)
      switch (p->word[0]) {

      case '(':
          if (specp)
            n++;
          l++;
          continue;

      case ')':
          if (specp)
            n++;
          l--;
          continue;

      case '>':
      case '<':
          if (l != 0) {
            if (specp)
                n++;
            continue;
          }
          if (p->next == p2)
            continue;
          if (any(RELPAR, p->next->word[0]))
            continue;
          n--;
          continue;

      default:
          if (!specp && l != 0)
            continue;
          n++;
          continue;
      }
    if (n < 0)
      n = 0;
    t = (struct command *) xcalloc(1, sizeof(*t));
    av = (Char **) xcalloc((size_t) (n + 1), sizeof(Char **));
    t->t_dcom = av;
    n = 0;
    if (p2->word[0] == ')')
      t->t_dflg = F_NOFORK;
    lp = 0;
    rp = 0;
    l = 0;
    for (p = p1; p != p2; p = p->next) {
      c = p->word[0];
      switch (c) {

      case '(':
          if (l == 0) {
            if (lp != 0 && !specp)
                seterror(ERR_BADPLP);
            lp = p->next;
          }
          l++;
          goto savep;

      case ')':
          l--;
          if (l == 0)
            rp = p;
          goto savep;

      case '>':
          if (l != 0)
            goto savep;
          if (p->word[1] == '>')
            t->t_dflg |= F_APPEND;
          if (p->next != p2 && eq(p->next->word, STRand)) {
            t->t_dflg |= F_STDERR, p = p->next;
            if (flags & (P_OUT | P_DIAG)) {
                seterror(ERR_OUTRED);
                continue;
            }
          }
          if (p->next != p2 && eq(p->next->word, STRbang))
            t->t_dflg |= F_OVERWRITE, p = p->next;
          if (p->next == p2) {
            seterror(ERR_MISRED);
            continue;
          }
          p = p->next;
          if (any(RELPAR, p->word[0])) {
            seterror(ERR_MISRED);
            continue;
          }
          if (((flags & P_OUT) && (flags & P_DIAG) == 0) || t->t_drit)
            seterror(ERR_OUTRED);
          else
            t->t_drit = Strsave(p->word);
          continue;

      case '<':
          if (l != 0)
            goto savep;
          if (p->word[1] == '<')
            t->t_dflg |= F_READ;
          if (p->next == p2) {
            seterror(ERR_MISRED);
            continue;
          }
          p = p->next;
          if (any(RELPAR, p->word[0])) {
            seterror(ERR_MISRED);
            continue;
          }
          if ((flags & P_HERE) && (t->t_dflg & F_READ))
            seterror(ERR_REDPAR);
          else if ((flags & P_IN) || t->t_dlef)
            seterror(ERR_INRED);
          else
            t->t_dlef = Strsave(p->word);
          continue;

    savep:
          if (!specp)
            continue;
      default:
          if (l != 0 && !specp)
            continue;
          if (seterr == 0)
            av[n] = Strsave(p->word);
          n++;
          continue;
      }
    }
    if (lp != 0 && !specp) {
      if (n != 0)
          seterror(ERR_BADPLPS);
      t->t_dtyp = NODE_PAREN;
      t->t_dspr = syn0(lp, rp, P_HERE);
    }
    else {
      if (n == 0)
          seterror(ERR_NULLCOM);
      t->t_dtyp = NODE_COMMAND;
    }
    return (t);
}

void
freesyn(t)
    register struct command *t;
{
    register Char **v;

    if (t == 0)
      return;
    switch (t->t_dtyp) {

    case NODE_COMMAND:
      for (v = t->t_dcom; *v; v++)
          xfree((ptr_t) * v);
      xfree((ptr_t) (t->t_dcom));
      xfree((ptr_t) t->t_dlef);
      xfree((ptr_t) t->t_drit);
      break;
    case NODE_PAREN:
      freesyn(t->t_dspr);
      xfree((ptr_t) t->t_dlef);
      xfree((ptr_t) t->t_drit);
      break;

    case NODE_AND:
    case NODE_OR:
    case NODE_PIPE:
    case NODE_LIST:
      freesyn(t->t_dcar), freesyn(t->t_dcdr);
      break;
    default:
      break;
    }
    xfree((ptr_t) t);
}

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