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minix/commands/ash/parser.c

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Initial revision
2005-04-21 16:53:53 +02:00
/*-
* Copyright (c) 1991 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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.
*/
#ifndef lint
static char sccsid[] = "@(#)parser.c 5.3 (Berkeley) 4/12/91";
#endif /* not lint */
#include "shell.h"
#include "parser.h"
#include "nodes.h"
#include "expand.h" /* defines rmescapes() */
#include "redir.h" /* defines copyfd() */
#include "syntax.h"
#include "options.h"
#include "input.h"
#include "output.h"
#include "var.h"
#include "error.h"
#include "memalloc.h"
#include "mystring.h"
/*
* Shell command parser.
*/
#define EOFMARKLEN 79
/* values returned by readtoken */
#include "token.def"
struct heredoc {
struct heredoc *next; /* next here document in list */
union node *here; /* redirection node */
char *eofmark; /* string indicating end of input */
int striptabs; /* if set, strip leading tabs */
};
struct heredoc *heredoclist; /* list of here documents to read */
int parsebackquote; /* nonzero if we are inside backquotes */
int doprompt; /* if set, prompt the user */
int needprompt; /* true if interactive and at start of line */
int lasttoken; /* last token read */
MKINIT int tokpushback; /* last token pushed back */
char *wordtext; /* text of last word returned by readtoken */
int checkkwd; /* 1 == check for kwds, 2 == also eat newlines */
struct nodelist *backquotelist;
union node *redirnode;
struct heredoc *heredoc;
int quoteflag; /* set if (part of) last token was quoted */
int startlinno; /* line # where last token started */
#define GDB_HACK 1 /* avoid local declarations which gdb can't handle */
#ifdef GDB_HACK
static const char argvars[5] = {CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'};
static const char types[] = "}-+?=";
#endif
STATIC union node *list __P((int));
STATIC union node *andor __P((void));
STATIC union node *pipeline __P((void));
STATIC union node *command __P((void));
STATIC union node *simplecmd __P((union node **, union node *));
STATIC void parsefname __P((void));
STATIC void parseheredoc __P((void));
STATIC int readtoken __P((void));
STATIC int readtoken1 __P((int, char const *, char *, int));
STATIC void attyline __P((void));
STATIC int noexpand __P((char *));
STATIC void synexpect __P((int));
STATIC void synerror __P((char *));
#if ATTY || READLINE
STATIC void putprompt __P((char *));
#else /* not ATTY */
#define putprompt(s) out2str(s)
#endif
/*
* Read and parse a command. Returns NEOF on end of file. (NULL is a
* valid parse tree indicating a blank line.)
*/
union node *
parsecmd(interact) {
int t;
extern int exitstatus;
doprompt = interact;
if (doprompt)
putprompt(exitstatus == 0 ? ps1val() : pseval());
needprompt = 0;
if ((t = readtoken()) == TEOF)
return NEOF;
if (t == TNL)
return NULL;
tokpushback++;
return list(1);
}
STATIC union node *
list(nlflag) {
union node *n1, *n2, *n3, **pn;
int first;
checkkwd = 2;
if (nlflag == 0 && tokendlist[peektoken()])
return NULL;
n1 = andor();
for (first = 1; ; first = 0) {
switch (readtoken()) {
case TBACKGND:
pn = &n1;
if (!first && n1->type == NSEMI) pn = &n1->nbinary.ch2;
if ((*pn)->type == NCMD || (*pn)->type == NPIPE) {
(*pn)->ncmd.backgnd = 1;
} else if ((*pn)->type == NREDIR) {
(*pn)->type = NBACKGND;
} else {
n3 = (union node *)stalloc(sizeof (struct nredir));
n3->type = NBACKGND;
n3->nredir.n = *pn;
n3->nredir.redirect = NULL;
*pn = n3;
}
goto tsemi;
case TNL:
tokpushback++;
/* fall through */
tsemi: case TSEMI:
if (readtoken() == TNL) {
parseheredoc();
if (nlflag)
return n1;
} else {
tokpushback++;
}
checkkwd = 2;
if (tokendlist[peektoken()])
return n1;
n2 = andor();
n3 = (union node *)stalloc(sizeof (struct nbinary));
n3->type = NSEMI;
n3->nbinary.ch1 = n1;
n3->nbinary.ch2 = n2;
n1 = n3;
break;
case TEOF:
if (heredoclist)
parseheredoc();
else
pungetc(); /* push back EOF on input */
return n1;
default:
if (nlflag)
synexpect(-1);
tokpushback++;
return n1;
}
}
}
STATIC union node *
andor() {
union node *n1, *n2, *n3;
int t;
n1 = pipeline();
for (;;) {
if ((t = readtoken()) == TAND) {
t = NAND;
} else if (t == TOR) {
t = NOR;
} else {
tokpushback++;
return n1;
}
n2 = pipeline();
n3 = (union node *)stalloc(sizeof (struct nbinary));
n3->type = t;
n3->nbinary.ch1 = n1;
n3->nbinary.ch2 = n2;
n1 = n3;
}
}
STATIC union node *
pipeline() {
union node *n1, *pipenode;
struct nodelist *lp, *prev;
n1 = command();
if (readtoken() == TPIPE) {
pipenode = (union node *)stalloc(sizeof (struct npipe));
pipenode->type = NPIPE;
pipenode->npipe.backgnd = 0;
lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
pipenode->npipe.cmdlist = lp;
lp->n = n1;
do {
prev = lp;
lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
lp->n = command();
prev->next = lp;
} while (readtoken() == TPIPE);
lp->next = NULL;
n1 = pipenode;
}
tokpushback++;
return n1;
}
STATIC union node *
command() {
union node *n1, *n2;
union node *ap, **app;
union node *cp, **cpp;
union node *redir, **rpp;
int t;
checkkwd = 2;
redir = 0;
rpp = &redir;
/* Check for redirection which may precede command */
while (readtoken() == TREDIR) {
*rpp = n2 = redirnode;
rpp = &n2->nfile.next;
parsefname();
}
tokpushback++;
switch (readtoken()) {
case TIF:
n1 = (union node *)stalloc(sizeof (struct nif));
n1->type = NIF;
n1->nif.test = list(0);
if (readtoken() != TTHEN)
synexpect(TTHEN);
n1->nif.ifpart = list(0);
n2 = n1;
while (readtoken() == TELIF) {
n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
n2 = n2->nif.elsepart;
n2->type = NIF;
n2->nif.test = list(0);
if (readtoken() != TTHEN)
synexpect(TTHEN);
n2->nif.ifpart = list(0);
}
if (lasttoken == TELSE)
n2->nif.elsepart = list(0);
else {
n2->nif.elsepart = NULL;
tokpushback++;
}
if (readtoken() != TFI)
synexpect(TFI);
checkkwd = 1;
break;
case TWHILE:
case TUNTIL: {
int got;
n1 = (union node *)stalloc(sizeof (struct nbinary));
n1->type = (lasttoken == TWHILE)? NWHILE : NUNTIL;
n1->nbinary.ch1 = list(0);
if ((got=readtoken()) != TDO) {
TRACE(("expecting DO got %s %s\n", tokname[got], got == TWORD ? wordtext : ""));
synexpect(TDO);
}
n1->nbinary.ch2 = list(0);
if (readtoken() != TDONE)
synexpect(TDONE);
checkkwd = 1;
break;
}
case TFOR:
if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
synerror("Bad for loop variable");
n1 = (union node *)stalloc(sizeof (struct nfor));
n1->type = NFOR;
n1->nfor.var = wordtext;
if (readtoken() == TWORD && ! quoteflag && equal(wordtext, "in")) {
app = ≈
while (readtoken() == TWORD) {
n2 = (union node *)stalloc(sizeof (struct narg));
n2->type = NARG;
n2->narg.text = wordtext;
n2->narg.backquote = backquotelist;
*app = n2;
app = &n2->narg.next;
}
*app = NULL;
n1->nfor.args = ap;
/* A newline or semicolon is required here to end
the list. */
if (lasttoken != TNL && lasttoken != TSEMI)
synexpect(-1);
} else {
#ifndef GDB_HACK
static const char argvars[5] = {CTLVAR, VSNORMAL|VSQUOTE,
'@', '=', '\0'};
#endif
n2 = (union node *)stalloc(sizeof (struct narg));
n2->type = NARG;
n2->narg.text = (char *)argvars;
n2->narg.backquote = NULL;
n2->narg.next = NULL;
n1->nfor.args = n2;
/* A newline or semicolon is optional here. Anything
else gets pushed back so we can read it again. */
if (lasttoken != TNL && lasttoken != TSEMI)
tokpushback++;
}
checkkwd = 2;
if ((t = readtoken()) == TDO)
t = TDONE;
else if (t == TBEGIN)
t = TEND;
else
synexpect(-1);
n1->nfor.body = list(0);
if (readtoken() != t)
synexpect(t);
checkkwd = 1;
break;
case TCASE:
n1 = (union node *)stalloc(sizeof (struct ncase));
n1->type = NCASE;
if (readtoken() != TWORD)
synexpect(TWORD);
n1->ncase.expr = n2 = (union node *)stalloc(sizeof (struct narg));
n2->type = NARG;
n2->narg.text = wordtext;
n2->narg.backquote = backquotelist;
n2->narg.next = NULL;
while (readtoken() == TNL);
if (lasttoken != TWORD || ! equal(wordtext, "in"))
synerror("expecting \"in\"");
cpp = &n1->ncase.cases;
while (checkkwd = 2, readtoken() == TWORD) {
*cpp = cp = (union node *)stalloc(sizeof (struct nclist));
cp->type = NCLIST;
app = &cp->nclist.pattern;
for (;;) {
*app = ap = (union node *)stalloc(sizeof (struct narg));
ap->type = NARG;
ap->narg.text = wordtext;
ap->narg.backquote = backquotelist;
if (readtoken() != TPIPE)
break;
app = &ap->narg.next;
if (readtoken() != TWORD)
synexpect(TWORD);
}
ap->narg.next = NULL;
if (lasttoken != TRP)
synexpect(TRP);
cp->nclist.body = list(0);
if ((t = readtoken()) == TESAC)
tokpushback++;
else if (t != TENDCASE)
synexpect(TENDCASE);
cpp = &cp->nclist.next;
}
*cpp = NULL;
if (lasttoken != TESAC)
synexpect(TESAC);
checkkwd = 1;
break;
case TLP:
n1 = (union node *)stalloc(sizeof (struct nredir));
n1->type = NSUBSHELL;
n1->nredir.n = list(0);
n1->nredir.redirect = NULL;
if (readtoken() != TRP)
synexpect(TRP);
checkkwd = 1;
break;
case TBEGIN:
n1 = list(0);
if (readtoken() != TEND)
synexpect(TEND);
checkkwd = 1;
break;
/* Handle an empty command like other simple commands. */
case TNL:
case TSEMI:
case TEND:
case TRP:
case TEOF:
case TWORD:
tokpushback++;
return simplecmd(rpp, redir);
default:
synexpect(-1);
}
/* Now check for redirection which may follow command */
while (readtoken() == TREDIR) {
*rpp = n2 = redirnode;
rpp = &n2->nfile.next;
parsefname();
}
tokpushback++;
*rpp = NULL;
if (redir) {
if (n1->type != NSUBSHELL) {
n2 = (union node *)stalloc(sizeof (struct nredir));
n2->type = NREDIR;
n2->nredir.n = n1;
n1 = n2;
}
n1->nredir.redirect = redir;
}
return n1;
}
STATIC union node *
simplecmd(rpp, redir)
union node **rpp, *redir;
{
union node *args, **app;
union node **orig_rpp = rpp;
union node *n;
/* If we don't have any redirections already, then we must reset
rpp to be the address of the local redir variable. */
if (redir == 0)
rpp = &redir;
args = NULL;
app = &args;
/* We save the incoming value, because we need this for shell
functions. There can not be a redirect or an argument between
the function name and the open parenthesis. */
orig_rpp = rpp;
for (;;) {
if (readtoken() == TWORD) {
n = (union node *)stalloc(sizeof (struct narg));
n->type = NARG;
n->narg.text = wordtext;
n->narg.backquote = backquotelist;
*app = n;
app = &n->narg.next;
} else if (lasttoken == TREDIR) {
*rpp = n = redirnode;
rpp = &n->nfile.next;
parsefname(); /* read name of redirection file */
} else if (lasttoken == TLP && app == &args->narg.next
&& rpp == orig_rpp) {
/* We have a function */
if (readtoken() != TRP)
synexpect(TRP);
#ifdef notdef
if (! goodname(n->narg.text))
synerror("Bad function name");
#endif
n->type = NDEFUN;
n->narg.next = command();
return n;
} else {
tokpushback++;
break;
}
}
*app = NULL;
*rpp = NULL;
n = (union node *)stalloc(sizeof (struct ncmd));
n->type = NCMD;
n->ncmd.backgnd = 0;
n->ncmd.args = args;
n->ncmd.redirect = redir;
return n;
}
STATIC void
parsefname() {
union node *n = redirnode;
if (readtoken() != TWORD)
synexpect(-1);
if (n->type == NHERE) {
struct heredoc *here = heredoc;
struct heredoc *p;
int i;
if (quoteflag == 0)
n->type = NXHERE;
TRACE(("Here document %d\n", n->type));
if (here->striptabs) {
while (*wordtext == '\t')
wordtext++;
}
if (! noexpand(wordtext) || (i = strlen(wordtext)) == 0 || i > EOFMARKLEN)
synerror("Illegal eof marker for << redirection");
rmescapes(wordtext);
here->eofmark = wordtext;
here->next = NULL;
if (heredoclist == NULL)
heredoclist = here;
else {
for (p = heredoclist ; p->next ; p = p->next);
p->next = here;
}
} else if (n->type == NTOFD || n->type == NFROMFD) {
if (is_digit(wordtext[0]))
n->ndup.dupfd = digit_val(wordtext[0]);
else if (wordtext[0] == '-')
n->ndup.dupfd = -1;
else
goto bad;
if (wordtext[1] != '\0') {
bad:
synerror("Bad fd number");
}
} else {
n->nfile.fname = (union node *)stalloc(sizeof (struct narg));
n = n->nfile.fname;
n->type = NARG;
n->narg.next = NULL;
n->narg.text = wordtext;
n->narg.backquote = backquotelist;
}
}
/*
* Input any here documents.
*/
STATIC void
parseheredoc() {
struct heredoc *here;
union node *n;
while (heredoclist) {
here = heredoclist;
heredoclist = here->next;
if (needprompt) {
putprompt(ps2val());
needprompt = 0;
}
readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
here->eofmark, here->striptabs);
n = (union node *)stalloc(sizeof (struct narg));
n->narg.type = NARG;
n->narg.next = NULL;
n->narg.text = wordtext;
n->narg.backquote = backquotelist;
here->here->nhere.doc = n;
}
}
STATIC int
peektoken() {
int t;
t = readtoken();
tokpushback++;
return (t);
}
STATIC int xxreadtoken();
STATIC int
readtoken() {
int t;
#if DEBUG
int alreadyseen = tokpushback;
#endif
t = xxreadtoken();
if (checkkwd) {
/*
* eat newlines
*/
if (checkkwd == 2) {
checkkwd = 0;
while (t == TNL) {
parseheredoc();
t = xxreadtoken();
}
} else
checkkwd = 0;
/*
* check for keywords
*/
if (t == TWORD && !quoteflag) {
register char *const *pp;
for (pp = parsekwd; *pp; pp++) {
if (**pp == *wordtext && equal(*pp, wordtext)) {
lasttoken = t = pp - parsekwd + KWDOFFSET;
TRACE(("keyword %s recognized\n", tokname[t]));
break;
}
}
}
}
#if DEBUG
if (!alreadyseen)
TRACE(("token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
else
TRACE(("reread token %s %s\n", tokname[t], t == TWORD ? wordtext : ""));
#endif
return (t);
}
/*
* Read the next input token.
* If the token is a word, we set backquotelist to the list of cmds in
* backquotes. We set quoteflag to true if any part of the word was
* quoted.
* If the token is TREDIR, then we set redirnode to a structure containing
* the redirection.
* In all cases, the variable startlinno is set to the number of the line
* on which the token starts.
*
* [Change comment: here documents and internal procedures]
* [Readtoken shouldn't have any arguments. Perhaps we should make the
* word parsing code into a separate routine. In this case, readtoken
* doesn't need to have any internal procedures, but parseword does.
* We could also make parseoperator in essence the main routine, and
* have parseword (readtoken1?) handle both words and redirection.]
*/
#define RETURN(token) return lasttoken = token
STATIC int
xxreadtoken() {
register c;
if (tokpushback) {
tokpushback = 0;
return lasttoken;
}
if (needprompt) {
putprompt(ps2val());
needprompt = 0;
}
startlinno = plinno;
for (;;) { /* until token or start of word found */
c = pgetc_macro();
if (c == ' ' || c == '\t')
continue; /* quick check for white space first */
switch (c) {
case ' ': case '\t':
continue;
case '#':
while ((c = pgetc()) != '\n' && c != PEOF);
pungetc();
continue;
case '\\':
if (pgetc() == '\n') {
startlinno = ++plinno;
if (doprompt)
putprompt(ps2val());
continue;
}
pungetc();
goto breakloop;
case '\n':
plinno++;
needprompt = doprompt;
RETURN(TNL);
case PEOF:
RETURN(TEOF);
case '&':
if (pgetc() == '&')
RETURN(TAND);
pungetc();
RETURN(TBACKGND);
case '|':
if (pgetc() == '|')
RETURN(TOR);
pungetc();
RETURN(TPIPE);
case ';':
if (pgetc() == ';')
RETURN(TENDCASE);
pungetc();
RETURN(TSEMI);
case '(':
RETURN(TLP);
case ')':
RETURN(TRP);
default:
goto breakloop;
}
}
breakloop:
return readtoken1(c, BASESYNTAX, (char *)NULL, 0);
#undef RETURN
}
/*
* If eofmark is NULL, read a word or a redirection symbol. If eofmark
* is not NULL, read a here document. In the latter case, eofmark is the
* word which marks the end of the document and striptabs is true if
* leading tabs should be stripped from the document. The argument firstc
* is the first character of the input token or document.
*
* Because C does not have internal subroutines, I have simulated them
* using goto's to implement the subroutine linkage. The following macros
* will run code that appears at the end of readtoken1.
*/
#define CHECKEND() {goto checkend; checkend_return:;}
#define PARSEREDIR() {goto parseredir; parseredir_return:;}
#define PARSESUB() {goto parsesub; parsesub_return:;}
#define PARSEBACKQOLD() {oldstyle = 1; goto parsebackq; parsebackq_oldreturn:;}
#define PARSEBACKQNEW() {oldstyle = 0; goto parsebackq; parsebackq_newreturn:;}
STATIC int
readtoken1(firstc, syntax, eofmark, striptabs)
int firstc;
char const *syntax;
char *eofmark;
int striptabs;
{
register c = firstc;
register char *out;
int len;
char line[EOFMARKLEN + 1];
struct nodelist *bqlist;
int quotef;
int dblquote;
int varnest;
int oldstyle;
startlinno = plinno;
dblquote = 0;
if (syntax == DQSYNTAX)
dblquote = 1;
quotef = 0;
bqlist = NULL;
varnest = 0;
STARTSTACKSTR(out);
loop: { /* for each line, until end of word */
#if ATTY
if (c == '\034' && doprompt
&& attyset() && ! equal(termval(), "emacs")) {
attyline();
if (syntax == BASESYNTAX)
return readtoken();
c = pgetc();
goto loop;
}
#endif
CHECKEND(); /* set c to PEOF if at end of here document */
for (;;) { /* until end of line or end of word */
CHECKSTRSPACE(3, out); /* permit 3 calls to USTPUTC */
switch(syntax[c]) {
case CNL: /* '\n' */
if (syntax == BASESYNTAX)
goto endword; /* exit outer loop */
USTPUTC(c, out);
plinno++;
if (doprompt) {
putprompt(ps2val());
}
c = pgetc();
goto loop; /* continue outer loop */
case CWORD:
USTPUTC(c, out);
break;
case CCTL:
if (eofmark == NULL || dblquote)
USTPUTC(CTLESC, out);
USTPUTC(c, out);
break;
case CBACK: /* backslash */
c = pgetc();
if (c == PEOF) {
USTPUTC('\\', out);
pungetc();
} else if (c == '\n') {
if (doprompt)
putprompt(ps2val());
} else {
if (dblquote && c != '\\' && c != '`' && c != '$'
&& (c != '"' || eofmark != NULL))
USTPUTC('\\', out);
if (SQSYNTAX[c] == CCTL)
USTPUTC(CTLESC, out);
USTPUTC(c, out);
quotef++;
}
break;
case CSQUOTE:
syntax = SQSYNTAX;
break;
case CDQUOTE:
syntax = DQSYNTAX;
dblquote = 1;
break;
case CENDQUOTE:
if (eofmark) {
USTPUTC(c, out);
} else {
syntax = BASESYNTAX;
quotef++;
dblquote = 0;
}
break;
case CVAR: /* '$' */
PARSESUB(); /* parse substitution */
break;
case CENDVAR: /* '}' */
if (varnest > 0) {
varnest--;
USTPUTC(CTLENDVAR, out);
} else {
USTPUTC(c, out);
}
break;
case CBQUOTE: /* '`' */
PARSEBACKQOLD();
break;
case CEOF:
goto endword; /* exit outer loop */
default:
if (varnest == 0)
goto endword; /* exit outer loop */
USTPUTC(c, out);
}
c = pgetc_macro();
}
}
endword:
if (syntax != BASESYNTAX && ! parsebackquote && eofmark == NULL)
synerror("Unterminated quoted string");
if (varnest != 0) {
startlinno = plinno;
synerror("Missing '}'");
}
USTPUTC('\0', out);
len = out - stackblock();
out = stackblock();
if (eofmark == NULL) {
if ((c == '>' || c == '<')
&& quotef == 0
&& len <= 2
&& (*out == '\0' || is_digit(*out))) {
PARSEREDIR();
return lasttoken = TREDIR;
} else {
pungetc();
}
}
quoteflag = quotef;
backquotelist = bqlist;
grabstackblock(len);
wordtext = out;
return lasttoken = TWORD;
/* end of readtoken routine */
/*
* Check to see whether we are at the end of the here document. When this
* is called, c is set to the first character of the next input line. If
* we are at the end of the here document, this routine sets the c to PEOF.
*/
checkend: {
if (eofmark) {
if (striptabs) {
while (c == '\t')
c = pgetc();
}
if (c == *eofmark) {
if (pfgets(line, sizeof line) != NULL) {
register char *p, *q;
p = line;
for (q = eofmark + 1 ; *q && *p == *q ; p++, q++);
if (*p == '\n' && *q == '\0') {
c = PEOF;
plinno++;
needprompt = doprompt;
} else {
ppushback(line, strlen(line));
}
}
}
}
goto checkend_return;
}
/*
* Parse a redirection operator. The variable "out" points to a string
* specifying the fd to be redirected. The variable "c" contains the
* first character of the redirection operator.
*/
parseredir: {
char fd = *out;
union node *np;
np = (union node *)stalloc(sizeof (struct nfile));
if (c == '>') {
np->nfile.fd = 1;
c = pgetc();
if (c == '>')
np->type = NAPPEND;
else if (c == '&')
np->type = NTOFD;
else {
np->type = NTO;
pungetc();
}
} else { /* c == '<' */
np->nfile.fd = 0;
c = pgetc();
if (c == '<') {
if (sizeof (struct nfile) != sizeof (struct nhere)) {
np = (union node *)stalloc(sizeof (struct nhere));
np->nfile.fd = 0;
}
np->type = NHERE;
heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
heredoc->here = np;
if ((c = pgetc()) == '-') {
heredoc->striptabs = 1;
} else {
heredoc->striptabs = 0;
pungetc();
}
} else if (c == '&')
np->type = NFROMFD;
else {
np->type = NFROM;
pungetc();
}
}
if (fd != '\0')
np->nfile.fd = digit_val(fd);
redirnode = np;
goto parseredir_return;
}
/*
* Parse a substitution. At this point, we have read the dollar sign
* and nothing else.
*/
parsesub: {
int subtype;
int typeloc;
int flags;
char *p;
#ifndef GDB_HACK
static const char types[] = "}-+?=";
#endif
c = pgetc();
if (c != '(' && c != '{' && !is_name(c) && !is_special(c)) {
USTPUTC('$', out);
pungetc();
} else if (c == '(') { /* $(command) */
PARSEBACKQNEW();
} else {
USTPUTC(CTLVAR, out);
typeloc = out - stackblock();
USTPUTC(VSNORMAL, out);
subtype = VSNORMAL;
if (c == '{') {
c = pgetc();
subtype = 0;
}
if (is_name(c)) {
do {
STPUTC(c, out);
c = pgetc();
} while (is_in_name(c));
} else {
if (! is_special(c))
badsub: synerror("Bad substitution");
USTPUTC(c, out);
c = pgetc();
}
STPUTC('=', out);
flags = 0;
if (subtype == 0) {
if (c == ':') {
flags = VSNUL;
c = pgetc();
}
p = strchr(types, c);
if (p == NULL)
goto badsub;
subtype = p - types + VSNORMAL;
} else {
pungetc();
}
if (dblquote)
flags |= VSQUOTE;
*(stackblock() + typeloc) = subtype | flags;
if (subtype != VSNORMAL)
varnest++;
}
goto parsesub_return;
}
/*
* Called to parse command substitutions. Newstyle is set if the command
* is enclosed inside $(...); nlpp is a pointer to the head of the linked
* list of commands (passed by reference), and savelen is the number of
* characters on the top of the stack which must be preserved.
*/
parsebackq: {
struct nodelist **nlpp;
int savepbq;
union node *n;
char *volatile str;
struct jmploc jmploc;
struct jmploc *volatile savehandler;
int savelen;
int savedoprompt;
savepbq = parsebackquote;
if (setjmp(jmploc.loc)) {
if (str)
ckfree(str);
parsebackquote = 0;
handler = savehandler;
longjmp(handler->loc, 1);
}
INTOFF;
str = NULL;
savelen = out - stackblock();
if (savelen > 0) {
str = ckmalloc(savelen);
bcopy(stackblock(), str, savelen);
}
savehandler = handler;
handler = &jmploc;
INTON;
if (oldstyle) {
/* We must read until the closing backquote, giving special
treatment to some slashes, and then push the string and
reread it as input, interpreting it normally. */
register char *out;
register c;
int savelen;
char *str;
STARTSTACKSTR(out);
while ((c = pgetc ()) != '`') {
if (c == '\\') {
c = pgetc ();
if (c != '\\' && c != '`' && c != '$'
&& (!dblquote || c != '"'))
STPUTC('\\', out);
}
if (c == '\n') {
plinno++;
if (doprompt)
putprompt(ps2val());
}
STPUTC(c, out);
}
STPUTC('\0', out);
savelen = out - stackblock();
if (savelen > 0) {
str = ckmalloc(savelen);
bcopy(stackblock(), str, savelen);
}
setinputstring(str, 1);
savedoprompt = doprompt;
doprompt = 0; /* no prompts while rereading string */
}
nlpp = &bqlist;
while (*nlpp)
nlpp = &(*nlpp)->next;
*nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
(*nlpp)->next = NULL;
parsebackquote = oldstyle;
n = list(0);
if (!oldstyle && (readtoken() != TRP))
synexpect(TRP);
(*nlpp)->n = n;
/* Start reading from old file again. */
if (oldstyle) {
popfile();
doprompt = savedoprompt;
}
while (stackblocksize() <= savelen)
growstackblock();
STARTSTACKSTR(out);
if (str) {
bcopy(str, out, savelen);
STADJUST(savelen, out);
INTOFF;
ckfree(str);
str = NULL;
INTON;
}
parsebackquote = savepbq;
handler = savehandler;
USTPUTC(CTLBACKQ + dblquote, out);
if (oldstyle)
goto parsebackq_oldreturn;
else
goto parsebackq_newreturn;
}
} /* end of readtoken */
#ifdef mkinit
RESET {
tokpushback = 0;
}
#endif
#if READLINE
/*
* Remember a prompt for use with readline if input and output is a terminal.
*/
STATIC void
putprompt(s)
char *s;
{
if (editable) {
r_use_prompt = s;
} else {
out2str(s);
}
}
#endif
#if ATTY
/*
* Called to process a command generated by atty. We execute the line,
* and catch any errors that occur so they don't propagate outside of
* this routine.
*/
STATIC void
attyline() {
char line[256];
struct stackmark smark;
struct jmploc jmploc;
struct jmploc *volatile savehandler;
if (pfgets(line, sizeof line) == NULL)
return; /* "can't happen" */
if (setjmp(jmploc.loc)) {
if (exception == EXERROR)
out2str("\033]D\n");
handler = savehandler;
longjmp(handler->loc, 1);
}
savehandler = handler;
handler = &jmploc;
setstackmark(&smark);
evalstring(line);
popstackmark(&smark);
handler = savehandler;
doprompt = 1;
}
/*
* Output a prompt for atty. We output the prompt as part of the
* appropriate escape sequence.
*/
STATIC void
putprompt(s)
char *s;
{
register char *p;
if (attyset() && ! equal(termval(), "emacs")) {
if (strchr(s, '\7'))
out2c('\7');
out2str("\033]P1;");
for (p = s ; *p ; p++) {
if ((unsigned)(*p - ' ') <= '~' - ' ')
out2c(*p);
}
out2c('\n');
} else {
out2str(s);
}
}
#endif
/*
* Returns true if the text contains nothing to expand (no dollar signs
* or backquotes).
*/
STATIC int
noexpand(text)
char *text;
{
register char *p;
register char c;
p = text;
while ((c = *p++) != '\0') {
if (c == CTLESC)
p++;
else if (BASESYNTAX[c] == CCTL)
return 0;
}
return 1;
}
/*
* Return true if the argument is a legal variable name (a letter or
* underscore followed by zero or more letters, underscores, and digits).
*/
int
goodname(name)
char *name;
{
register char *p;
p = name;
if (! is_name(*p))
return 0;
while (*++p) {
if (! is_in_name(*p))
return 0;
}
return 1;
}
/*
* Called when an unexpected token is read during the parse. The argument
* is the token that is expected, or -1 if more than one type of token can
* occur at this point.
*/
STATIC void
synexpect(token) {
char msg[64];
if (token >= 0) {
fmtstr(msg, 64, "%s unexpected (expecting %s)",
tokname[lasttoken], tokname[token]);
} else {
fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
}
synerror(msg);
}
STATIC void
synerror(msg)
char *msg;
{
if (commandname)
outfmt(&errout, "%s: %d: ", commandname, startlinno);
outfmt(&errout, "Syntax error: %s\n", msg);
error((char *)NULL);
}
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