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freebsd-skq/bin/sh/parser.c
Jilles Tjoelker 135ff4b5b0 sh: Fix some issues with aliases and case, by importing dash checkkwd code. 
This moves the function of the noaliases variable into the checkkwd
variable. This way it is properly reset on errors and aliases can be used
normally in the commands for each case (the case labels recognize the
keyword esac but no aliases).

The new code is clearer as well.

Obtained from:	dash
2010-11-02 23:44:29 +00:00

1840 lines
40 KiB
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/*-
* 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.
* 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
#if 0
static char sccsid[] = "@(#)parser.c 8.7 (Berkeley) 5/16/95";
#endif
#endif /* not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include "shell.h"
#include "parser.h"
#include "nodes.h"
#include "expand.h" /* defines rmescapes() */
#include "syntax.h"
#include "options.h"
#include "input.h"
#include "output.h"
#include "var.h"
#include "error.h"
#include "memalloc.h"
#include "mystring.h"
#include "alias.h"
#include "show.h"
#include "eval.h"
#include "exec.h" /* to check for special builtins */
#ifndef NO_HISTORY
#include "myhistedit.h"
#endif
/*
* Shell command parser.
*/
#define EOFMARKLEN 79
#define PROMPTLEN 128
/* values of checkkwd variable */
#define CHKALIAS 0x1
#define CHKKWD 0x2
#define CHKNL 0x4
/* values returned by readtoken */
#include "token.h"
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 parser_temp {
struct parser_temp *next;
void *data;
};
static struct heredoc *heredoclist; /* list of here documents to read */
static int doprompt; /* if set, prompt the user */
static int needprompt; /* true if interactive and at start of line */
static int lasttoken; /* last token read */
MKINIT int tokpushback; /* last token pushed back */
static char *wordtext; /* text of last word returned by readtoken */
MKINIT int checkkwd; /* 1 == check for kwds, 2 == also eat newlines */
static struct nodelist *backquotelist;
static union node *redirnode;
static struct heredoc *heredoc;
static int quoteflag; /* set if (part of) last token was quoted */
static int startlinno; /* line # where last token started */
static int funclinno; /* line # where the current function started */
static struct parser_temp *parser_temp;
static union node *list(int, int);
static union node *andor(void);
static union node *pipeline(void);
static union node *command(void);
static union node *simplecmd(union node **, union node *);
static union node *makename(void);
static void parsefname(void);
static void parseheredoc(void);
static int peektoken(void);
static int readtoken(void);
static int xxreadtoken(void);
static int readtoken1(int, char const *, char *, int);
static int noexpand(char *);
static void synexpect(int) __dead2;
static void synerror(const char *) __dead2;
static void setprompt(int);
static void *
parser_temp_alloc(size_t len)
{
struct parser_temp *t;
INTOFF;
t = ckmalloc(sizeof(*t));
t->data = NULL;
t->next = parser_temp;
parser_temp = t;
t->data = ckmalloc(len);
INTON;
return t->data;
}
static void *
parser_temp_realloc(void *ptr, size_t len)
{
struct parser_temp *t;
INTOFF;
t = parser_temp;
if (ptr != t->data)
error("bug: parser_temp_realloc misused");
t->data = ckrealloc(t->data, len);
INTON;
return t->data;
}
static void
parser_temp_free_upto(void *ptr)
{
struct parser_temp *t;
int done = 0;
INTOFF;
while (parser_temp != NULL && !done) {
t = parser_temp;
parser_temp = t->next;
done = t->data == ptr;
ckfree(t->data);
ckfree(t);
}
INTON;
if (!done)
error("bug: parser_temp_free_upto misused");
}
static void
parser_temp_free_all(void)
{
struct parser_temp *t;
INTOFF;
while (parser_temp != NULL) {
t = parser_temp;
parser_temp = t->next;
ckfree(t->data);
ckfree(t);
}
INTON;
}
/*
* Read and parse a command. Returns NEOF on end of file. (NULL is a
* valid parse tree indicating a blank line.)
*/
union node *
parsecmd(int interact)
{
int t;
/* This assumes the parser is not re-entered,
* which could happen if we add command substitution on PS1/PS2.
*/
parser_temp_free_all();
heredoclist = NULL;
tokpushback = 0;
doprompt = interact;
if (doprompt)
setprompt(1);
else
setprompt(0);
needprompt = 0;
t = readtoken();
if (t == TEOF)
return NEOF;
if (t == TNL)
return NULL;
tokpushback++;
return list(1, 1);
}
static union node *
list(int nlflag, int erflag)
{
union node *ntop, *n1, *n2, *n3;
int tok;
checkkwd = CHKNL | CHKKWD | CHKALIAS;
if (!nlflag && !erflag && tokendlist[peektoken()])
return NULL;
ntop = n1 = NULL;
for (;;) {
n2 = andor();
tok = readtoken();
if (tok == TBACKGND) {
if (n2->type == NCMD || n2->type == NPIPE) {
n2->ncmd.backgnd = 1;
} else if (n2->type == NREDIR) {
n2->type = NBACKGND;
} else {
n3 = (union node *)stalloc(sizeof (struct nredir));
n3->type = NBACKGND;
n3->nredir.n = n2;
n3->nredir.redirect = NULL;
n2 = n3;
}
}
if (ntop == NULL)
ntop = n2;
else if (n1 == NULL) {
n1 = (union node *)stalloc(sizeof (struct nbinary));
n1->type = NSEMI;
n1->nbinary.ch1 = ntop;
n1->nbinary.ch2 = n2;
ntop = n1;
}
else {
n3 = (union node *)stalloc(sizeof (struct nbinary));
n3->type = NSEMI;
n3->nbinary.ch1 = n1->nbinary.ch2;
n3->nbinary.ch2 = n2;
n1->nbinary.ch2 = n3;
n1 = n3;
}
switch (tok) {
case TBACKGND:
case TSEMI:
tok = readtoken();
/* FALLTHROUGH */
case TNL:
if (tok == TNL) {
parseheredoc();
if (nlflag)
return ntop;
} else if (tok == TEOF && nlflag) {
parseheredoc();
return ntop;
} else {
tokpushback++;
}
checkkwd = CHKNL | CHKKWD | CHKALIAS;
if (!nlflag && !erflag && tokendlist[peektoken()])
return ntop;
break;
case TEOF:
if (heredoclist)
parseheredoc();
else
pungetc(); /* push back EOF on input */
return ntop;
default:
if (nlflag || erflag)
synexpect(-1);
tokpushback++;
return ntop;
}
}
}
static union node *
andor(void)
{
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(void)
{
union node *n1, *n2, *pipenode;
struct nodelist *lp, *prev;
int negate, t;
negate = 0;
checkkwd = CHKNL | CHKKWD | CHKALIAS;
TRACE(("pipeline: entered\n"));
while (readtoken() == TNOT)
negate = !negate;
tokpushback++;
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));
checkkwd = CHKNL | CHKKWD | CHKALIAS;
t = readtoken();
tokpushback++;
if (t == TNOT)
lp->n = pipeline();
else
lp->n = command();
prev->next = lp;
} while (readtoken() == TPIPE);
lp->next = NULL;
n1 = pipenode;
}
tokpushback++;
if (negate) {
n2 = (union node *)stalloc(sizeof (struct nnot));
n2->type = NNOT;
n2->nnot.com = n1;
return n2;
} else
return n1;
}
static union node *
command(void)
{
union node *n1, *n2;
union node *ap, **app;
union node *cp, **cpp;
union node *redir, **rpp;
int t;
checkkwd = CHKNL | CHKKWD | CHKALIAS;
redir = NULL;
n1 = NULL;
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;
if ((n1->nif.test = list(0, 0)) == NULL)
synexpect(-1);
if (readtoken() != TTHEN)
synexpect(TTHEN);
n1->nif.ifpart = list(0, 0);
n2 = n1;
while (readtoken() == TELIF) {
n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
n2 = n2->nif.elsepart;
n2->type = NIF;
if ((n2->nif.test = list(0, 0)) == NULL)
synexpect(-1);
if (readtoken() != TTHEN)
synexpect(TTHEN);
n2->nif.ifpart = list(0, 0);
}
if (lasttoken == TELSE)
n2->nif.elsepart = list(0, 0);
else {
n2->nif.elsepart = NULL;
tokpushback++;
}
if (readtoken() != TFI)
synexpect(TFI);
checkkwd = CHKKWD | CHKALIAS;
break;
case TWHILE:
case TUNTIL: {
int got;
n1 = (union node *)stalloc(sizeof (struct nbinary));
n1->type = (lasttoken == TWHILE)? NWHILE : NUNTIL;
if ((n1->nbinary.ch1 = list(0, 0)) == NULL)
synexpect(-1);
if ((got=readtoken()) != TDO) {
TRACE(("expecting DO got %s %s\n", tokname[got], got == TWORD ? wordtext : ""));
synexpect(TDO);
}
n1->nbinary.ch2 = list(0, 0);
if (readtoken() != TDONE)
synexpect(TDONE);
checkkwd = CHKKWD | CHKALIAS;
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;
while (readtoken() == TNL)
;
if (lasttoken == TWORD && ! quoteflag && equal(wordtext, "in")) {
app = &ap;
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;
if (lasttoken != TNL && lasttoken != TSEMI)
synexpect(-1);
} else {
static char argvars[5] = {
CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0'
};
n2 = (union node *)stalloc(sizeof (struct narg));
n2->type = NARG;
n2->narg.text = argvars;
n2->narg.backquote = NULL;
n2->narg.next = NULL;
n1->nfor.args = n2;
/*
* Newline or semicolon here is optional (but note
* that the original Bourne shell only allowed NL).
*/
if (lasttoken != TNL && lasttoken != TSEMI)
tokpushback++;
}
checkkwd = CHKNL | CHKKWD | CHKALIAS;
if ((t = readtoken()) == TDO)
t = TDONE;
else if (t == TBEGIN)
t = TEND;
else
synexpect(-1);
n1->nfor.body = list(0, 0);
if (readtoken() != t)
synexpect(t);
checkkwd = CHKKWD | CHKALIAS;
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;
checkkwd = CHKNL | CHKKWD, readtoken();
while (lasttoken != TESAC) {
*cpp = cp = (union node *)stalloc(sizeof (struct nclist));
cp->type = NCLIST;
app = &cp->nclist.pattern;
if (lasttoken == TLP)
readtoken();
for (;;) {
*app = ap = (union node *)stalloc(sizeof (struct narg));
ap->type = NARG;
ap->narg.text = wordtext;
ap->narg.backquote = backquotelist;
checkkwd = CHKNL | CHKKWD;
if (readtoken() != TPIPE)
break;
app = &ap->narg.next;
readtoken();
}
ap->narg.next = NULL;
if (lasttoken != TRP)
synexpect(TRP);
cp->nclist.body = list(0, 0);
checkkwd = CHKNL | CHKKWD | CHKALIAS;
if ((t = readtoken()) != TESAC) {
if (t != TENDCASE)
synexpect(TENDCASE);
else
checkkwd = CHKNL | CHKKWD, readtoken();
}
cpp = &cp->nclist.next;
}
*cpp = NULL;
checkkwd = CHKKWD | CHKALIAS;
break;
case TLP:
n1 = (union node *)stalloc(sizeof (struct nredir));
n1->type = NSUBSHELL;
n1->nredir.n = list(0, 0);
n1->nredir.redirect = NULL;
if (readtoken() != TRP)
synexpect(TRP);
checkkwd = CHKKWD | CHKALIAS;
break;
case TBEGIN:
n1 = list(0, 0);
if (readtoken() != TEND)
synexpect(TEND);
checkkwd = CHKKWD | CHKALIAS;
break;
/* Handle an empty command like other simple commands. */
case TBACKGND:
case TSEMI:
case TAND:
case TOR:
/*
* An empty command before a ; doesn't make much sense, and
* should certainly be disallowed in the case of `if ;'.
*/
if (!redir)
synexpect(-1);
case TNL:
case TEOF:
case TWORD:
case TRP:
tokpushback++;
n1 = simplecmd(rpp, redir);
return n1;
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(union node **rpp, union node *redir)
{
union node *args, **app;
union node **orig_rpp = rpp;
union node *n = NULL;
int special;
/* 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);
funclinno = plinno;
/*
* - Require plain text.
* - Functions with '/' cannot be called.
* - Reject name=().
* - Reject ksh extended glob patterns.
*/
if (!noexpand(n->narg.text) || quoteflag ||
strchr(n->narg.text, '/') ||
strchr("!%*+-=?@}~",
n->narg.text[strlen(n->narg.text) - 1]))
synerror("Bad function name");
rmescapes(n->narg.text);
if (find_builtin(n->narg.text, &special) >= 0 &&
special)
synerror("Cannot override a special builtin with a function");
n->type = NDEFUN;
n->narg.next = command();
funclinno = 0;
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 union node *
makename(void)
{
union node *n;
n = (union node *)stalloc(sizeof (struct narg));
n->type = NARG;
n->narg.next = NULL;
n->narg.text = wordtext;
n->narg.backquote = backquotelist;
return n;
}
void
fixredir(union node *n, const char *text, int err)
{
TRACE(("Fix redir %s %d\n", text, err));
if (!err)
n->ndup.vname = NULL;
if (is_digit(text[0]) && text[1] == '\0')
n->ndup.dupfd = digit_val(text[0]);
else if (text[0] == '-' && text[1] == '\0')
n->ndup.dupfd = -1;
else {
if (err)
synerror("Bad fd number");
else
n->ndup.vname = makename();
}
}
static void
parsefname(void)
{
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) {
fixredir(n, wordtext, 0);
} else {
n->nfile.fname = makename();
}
}
/*
* Input any here documents.
*/
static void
parseheredoc(void)
{
struct heredoc *here;
union node *n;
while (heredoclist) {
here = heredoclist;
heredoclist = here->next;
if (needprompt) {
setprompt(2);
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(void)
{
int t;
t = readtoken();
tokpushback++;
return (t);
}
static int
readtoken(void)
{
int t;
struct alias *ap;
#ifdef DEBUG
int alreadyseen = tokpushback;
#endif
top:
t = xxreadtoken();
/*
* eat newlines
*/
if (checkkwd & CHKNL) {
while (t == TNL) {
parseheredoc();
t = xxreadtoken();
}
}
/*
* check for keywords and aliases
*/
if (t == TWORD && !quoteflag)
{
const char * const *pp;
if (checkkwd & CHKKWD)
for (pp = parsekwd; *pp; pp++) {
if (**pp == *wordtext && equal(*pp, wordtext))
{
lasttoken = t = pp - parsekwd + KWDOFFSET;
TRACE(("keyword %s recognized\n", tokname[t]));
goto out;
}
}
if (checkkwd & CHKALIAS &&
(ap = lookupalias(wordtext, 1)) != NULL) {
pushstring(ap->val, strlen(ap->val), ap);
goto top;
}
}
out:
if (t != TNOT)
checkkwd = 0;
#ifdef 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(void)
{
int c;
if (tokpushback) {
tokpushback = 0;
return lasttoken;
}
if (needprompt) {
setprompt(2);
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)
setprompt(2);
else
setprompt(0);
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
}
#define MAXNEST_static 8
struct tokenstate
{
const char *syntax; /* *SYNTAX */
int parenlevel; /* levels of parentheses in arithmetic */
enum tokenstate_category
{
TSTATE_TOP,
TSTATE_VAR_OLD, /* ${var+-=?}, inherits dquotes */
TSTATE_VAR_NEW, /* other ${var...}, own dquote state */
TSTATE_ARITH
} category;
};
/*
* Called to parse command substitutions.
*/
static char *
parsebackq(char *out, struct nodelist **pbqlist,
int oldstyle, int dblquote, int quoted)
{
struct nodelist **nlpp;
union node *n;
char *volatile str;
struct jmploc jmploc;
struct jmploc *const savehandler = handler;
int savelen;
int saveprompt;
const int bq_startlinno = plinno;
char *volatile ostr = NULL;
struct parsefile *const savetopfile = getcurrentfile();
struct heredoc *const saveheredoclist = heredoclist;
struct heredoc *here;
str = NULL;
if (setjmp(jmploc.loc)) {
popfilesupto(savetopfile);
if (str)
ckfree(str);
if (ostr)
ckfree(ostr);
heredoclist = saveheredoclist;
handler = savehandler;
if (exception == EXERROR) {
startlinno = bq_startlinno;
synerror("Error in command substitution");
}
longjmp(handler->loc, 1);
}
INTOFF;
savelen = out - stackblock();
if (savelen > 0) {
str = ckmalloc(savelen);
memcpy(str, stackblock(), savelen);
}
handler = &jmploc;
heredoclist = NULL;
INTON;
if (oldstyle) {
/* We must read until the closing backquote, giving special
treatment to some slashes, and then push the string and
reread it as input, interpreting it normally. */
char *oout;
int c;
int olen;
STARTSTACKSTR(oout);
for (;;) {
if (needprompt) {
setprompt(2);
needprompt = 0;
}
switch (c = pgetc()) {
case '`':
goto done;
case '\\':
if ((c = pgetc()) == '\n') {
plinno++;
if (doprompt)
setprompt(2);
else
setprompt(0);
/*
* If eating a newline, avoid putting
* the newline into the new character
* stream (via the STPUTC after the
* switch).
*/
continue;
}
if (c != '\\' && c != '`' && c != '$'
&& (!dblquote || c != '"'))
STPUTC('\\', oout);
break;
case '\n':
plinno++;
needprompt = doprompt;
break;
case PEOF:
startlinno = plinno;
synerror("EOF in backquote substitution");
break;
default:
break;
}
STPUTC(c, oout);
}
done:
STPUTC('\0', oout);
olen = oout - stackblock();
INTOFF;
ostr = ckmalloc(olen);
memcpy(ostr, stackblock(), olen);
setinputstring(ostr, 1);
INTON;
}
nlpp = pbqlist;
while (*nlpp)
nlpp = &(*nlpp)->next;
*nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
(*nlpp)->next = NULL;
if (oldstyle) {
saveprompt = doprompt;
doprompt = 0;
}
n = list(0, oldstyle);
if (oldstyle)
doprompt = saveprompt;
else {
if (readtoken() != TRP)
synexpect(TRP);
}
(*nlpp)->n = n;
if (oldstyle) {
/*
* Start reading from old file again, ignoring any pushed back
* tokens left from the backquote parsing
*/
popfile();
tokpushback = 0;
}
while (stackblocksize() <= savelen)
growstackblock();
STARTSTACKSTR(out);
INTOFF;
if (str) {
memcpy(out, str, savelen);
STADJUST(savelen, out);
ckfree(str);
str = NULL;
}
if (ostr) {
ckfree(ostr);
ostr = NULL;
}
here = saveheredoclist;
if (here != NULL) {
while (here->next != NULL)
here = here->next;
here->next = heredoclist;
heredoclist = saveheredoclist;
}
handler = savehandler;
INTON;
if (quoted)
USTPUTC(CTLBACKQ | CTLQUOTE, out);
else
USTPUTC(CTLBACKQ, out);
return out;
}
/*
* 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 PARSEARITH() {goto parsearith; parsearith_return:;}
static int
readtoken1(int firstc, char const *initialsyntax, char *eofmark, int striptabs)
{
int c = firstc;
char *out;
int len;
char line[EOFMARKLEN + 1];
struct nodelist *bqlist;
int quotef;
int newvarnest;
int level;
int synentry;
struct tokenstate state_static[MAXNEST_static];
int maxnest = MAXNEST_static;
struct tokenstate *state = state_static;
startlinno = plinno;
quotef = 0;
bqlist = NULL;
newvarnest = 0;
level = 0;
state[level].syntax = initialsyntax;
state[level].parenlevel = 0;
state[level].category = TSTATE_TOP;
STARTSTACKSTR(out);
loop: { /* for each line, until end of word */
CHECKEND(); /* set c to PEOF if at end of here document */
for (;;) { /* until end of line or end of word */
CHECKSTRSPACE(4, out); /* permit 4 calls to USTPUTC */
synentry = state[level].syntax[c];
switch(synentry) {
case CNL: /* '\n' */
if (state[level].syntax == BASESYNTAX)
goto endword; /* exit outer loop */
USTPUTC(c, out);
plinno++;
if (doprompt)
setprompt(2);
else
setprompt(0);
c = pgetc();
goto loop; /* continue outer loop */
case CWORD:
USTPUTC(c, out);
break;
case CCTL:
if (eofmark == NULL || initialsyntax != SQSYNTAX)
USTPUTC(CTLESC, out);
USTPUTC(c, out);
break;
case CBACK: /* backslash */
c = pgetc();
if (c == PEOF) {
USTPUTC('\\', out);
pungetc();
} else if (c == '\n') {
plinno++;
if (doprompt)
setprompt(2);
else
setprompt(0);
} else {
if (state[level].syntax == DQSYNTAX &&
c != '\\' && c != '`' && c != '$' &&
(c != '"' || (eofmark != NULL &&
newvarnest == 0)) &&
(c != '}' || state[level].category != TSTATE_VAR_OLD))
USTPUTC('\\', out);
if ((eofmark == NULL ||
newvarnest > 0) &&
state[level].syntax == BASESYNTAX)
USTPUTC(CTLQUOTEMARK, out);
if (SQSYNTAX[c] == CCTL)
USTPUTC(CTLESC, out);
USTPUTC(c, out);
if ((eofmark == NULL ||
newvarnest > 0) &&
state[level].syntax == BASESYNTAX &&
state[level].category == TSTATE_VAR_OLD)
USTPUTC(CTLQUOTEEND, out);
quotef++;
}
break;
case CSQUOTE:
USTPUTC(CTLQUOTEMARK, out);
state[level].syntax = SQSYNTAX;
break;
case CDQUOTE:
USTPUTC(CTLQUOTEMARK, out);
state[level].syntax = DQSYNTAX;
break;
case CENDQUOTE:
if (eofmark != NULL && newvarnest == 0)
USTPUTC(c, out);
else {
if (state[level].category == TSTATE_VAR_OLD)
USTPUTC(CTLQUOTEEND, out);
state[level].syntax = BASESYNTAX;
quotef++;
}
break;
case CVAR: /* '$' */
PARSESUB(); /* parse substitution */
break;
case CENDVAR: /* '}' */
if (level > 0 &&
((state[level].category == TSTATE_VAR_OLD &&
state[level].syntax ==
state[level - 1].syntax) ||
(state[level].category == TSTATE_VAR_NEW &&
state[level].syntax == BASESYNTAX))) {
if (state[level].category == TSTATE_VAR_NEW)
newvarnest--;
level--;
USTPUTC(CTLENDVAR, out);
} else {
USTPUTC(c, out);
}
break;
case CLP: /* '(' in arithmetic */
state[level].parenlevel++;
USTPUTC(c, out);
break;
case CRP: /* ')' in arithmetic */
if (state[level].parenlevel > 0) {
USTPUTC(c, out);
--state[level].parenlevel;
} else {
if (pgetc() == ')') {
if (level > 0 &&
state[level].category == TSTATE_ARITH) {
level--;
USTPUTC(CTLENDARI, out);
} else
USTPUTC(')', out);
} else {
/*
* unbalanced parens
* (don't 2nd guess - no error)
*/
pungetc();
USTPUTC(')', out);
}
}
break;
case CBQUOTE: /* '`' */
out = parsebackq(out, &bqlist, 1,
state[level].syntax == DQSYNTAX &&
(eofmark == NULL || newvarnest > 0),
state[level].syntax == DQSYNTAX || state[level].syntax == ARISYNTAX);
break;
case CEOF:
goto endword; /* exit outer loop */
case CIGN:
break;
default:
if (level == 0)
goto endword; /* exit outer loop */
USTPUTC(c, out);
}
c = pgetc_macro();
}
}
endword:
if (state[level].syntax == ARISYNTAX)
synerror("Missing '))'");
if (state[level].syntax != BASESYNTAX && eofmark == NULL)
synerror("Unterminated quoted string");
if (state[level].category == TSTATE_VAR_OLD ||
state[level].category == TSTATE_VAR_NEW) {
startlinno = plinno;
synerror("Missing '}'");
}
if (state != state_static)
parser_temp_free_upto(state);
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) {
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 {
pushstring(line, strlen(line), NULL);
}
}
}
}
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 if (c == '|')
np->type = NCLOBBER;
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 if (c == '>')
np->type = NFROMTO;
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: {
char buf[10];
int subtype;
int typeloc;
int flags;
char *p;
static const char types[] = "}-+?=";
int bracketed_name = 0; /* used to handle ${[0-9]*} variables */
int i;
int linno;
int length;
c = pgetc();
if (c != '(' && c != '{' && (is_eof(c) || !is_name(c)) &&
!is_special(c)) {
USTPUTC('$', out);
pungetc();
} else if (c == '(') { /* $(command) or $((arith)) */
if (pgetc() == '(') {
PARSEARITH();
} else {
pungetc();
out = parsebackq(out, &bqlist, 0,
state[level].syntax == DQSYNTAX &&
(eofmark == NULL || newvarnest > 0),
state[level].syntax == DQSYNTAX ||
state[level].syntax == ARISYNTAX);
}
} else {
USTPUTC(CTLVAR, out);
typeloc = out - stackblock();
USTPUTC(VSNORMAL, out);
subtype = VSNORMAL;
flags = 0;
if (c == '{') {
bracketed_name = 1;
c = pgetc();
if (c == '#') {
if ((c = pgetc()) == '}')
c = '#';
else
subtype = VSLENGTH;
}
else
subtype = 0;
}
if (!is_eof(c) && is_name(c)) {
length = 0;
do {
STPUTC(c, out);
c = pgetc();
length++;
} while (!is_eof(c) && is_in_name(c));
if (length == 6 &&
strncmp(out - length, "LINENO", length) == 0) {
/* Replace the variable name with the
* current line number. */
linno = plinno;
if (funclinno != 0)
linno -= funclinno - 1;
snprintf(buf, sizeof(buf), "%d", linno);
STADJUST(-6, out);
for (i = 0; buf[i] != '\0'; i++)
STPUTC(buf[i], out);
flags |= VSLINENO;
}
} else if (is_digit(c)) {
if (bracketed_name) {
do {
STPUTC(c, out);
c = pgetc();
} while (is_digit(c));
} else {
STPUTC(c, out);
c = pgetc();
}
} else {
if (! is_special(c)) {
subtype = VSERROR;
if (c == '}')
pungetc();
else if (c == '\n' || c == PEOF)
synerror("Unexpected end of line in substitution");
else
USTPUTC(c, out);
} else {
USTPUTC(c, out);
c = pgetc();
}
}
if (subtype == 0) {
switch (c) {
case ':':
flags |= VSNUL;
c = pgetc();
/*FALLTHROUGH*/
default:
p = strchr(types, c);
if (p == NULL) {
if (c == '\n' || c == PEOF)
synerror("Unexpected end of line in substitution");
if (flags == VSNUL)
STPUTC(':', out);
STPUTC(c, out);
subtype = VSERROR;
} else
subtype = p - types + VSNORMAL;
break;
case '%':
case '#':
{
int cc = c;
subtype = c == '#' ? VSTRIMLEFT :
VSTRIMRIGHT;
c = pgetc();
if (c == cc)
subtype++;
else
pungetc();
break;
}
}
} else if (subtype != VSERROR) {
pungetc();
}
STPUTC('=', out);
if (subtype != VSLENGTH && (state[level].syntax == DQSYNTAX ||
state[level].syntax == ARISYNTAX))
flags |= VSQUOTE;
*(stackblock() + typeloc) = subtype | flags;
if (subtype != VSNORMAL) {
if (level + 1 >= maxnest) {
maxnest *= 2;
if (state == state_static) {
state = parser_temp_alloc(
maxnest * sizeof(*state));
memcpy(state, state_static,
MAXNEST_static * sizeof(*state));
} else
state = parser_temp_realloc(state,
maxnest * sizeof(*state));
}
level++;
state[level].parenlevel = 0;
if (subtype == VSMINUS || subtype == VSPLUS ||
subtype == VSQUESTION || subtype == VSASSIGN) {
/*
* For operators that were in the Bourne shell,
* inherit the double-quote state.
*/
state[level].syntax = state[level - 1].syntax;
state[level].category = TSTATE_VAR_OLD;
} else {
/*
* The other operators take a pattern,
* so go to BASESYNTAX.
* Also, ' and " are now special, even
* in here documents.
*/
state[level].syntax = BASESYNTAX;
state[level].category = TSTATE_VAR_NEW;
newvarnest++;
}
}
}
goto parsesub_return;
}
/*
* Parse an arithmetic expansion (indicate start of one and set state)
*/
parsearith: {
if (level + 1 >= maxnest) {
maxnest *= 2;
if (state == state_static) {
state = parser_temp_alloc(
maxnest * sizeof(*state));
memcpy(state, state_static,
MAXNEST_static * sizeof(*state));
} else
state = parser_temp_realloc(state,
maxnest * sizeof(*state));
}
level++;
state[level].syntax = ARISYNTAX;
state[level].parenlevel = 0;
state[level].category = TSTATE_ARITH;
USTPUTC(CTLARI, out);
if (state[level - 1].syntax == DQSYNTAX)
USTPUTC('"',out);
else
USTPUTC(' ',out);
goto parsearith_return;
}
} /* end of readtoken */
#ifdef mkinit
RESET {
tokpushback = 0;
checkkwd = 0;
}
#endif
/*
* Returns true if the text contains nothing to expand (no dollar signs
* or backquotes).
*/
static int
noexpand(char *text)
{
char *p;
char c;
p = text;
while ((c = *p++) != '\0') {
if ( c == CTLQUOTEMARK)
continue;
if (c == CTLESC)
p++;
else if (BASESYNTAX[(int)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(const char *name)
{
const 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(int 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(const char *msg)
{
if (commandname)
outfmt(out2, "%s: %d: ", commandname, startlinno);
outfmt(out2, "Syntax error: %s\n", msg);
error((char *)NULL);
}
static void
setprompt(int which)
{
whichprompt = which;
#ifndef NO_HISTORY
if (!el)
#endif
{
out2str(getprompt(NULL));
flushout(out2);
}
}
/*
* called by editline -- any expansions to the prompt
* should be added here.
*/
char *
getprompt(void *unused __unused)
{
static char ps[PROMPTLEN];
char *fmt;
const char *pwd;
int i, trim;
static char internal_error[] = "??";
/*
* Select prompt format.
*/
switch (whichprompt) {
case 0:
fmt = nullstr;
break;
case 1:
fmt = ps1val();
break;
case 2:
fmt = ps2val();
break;
default:
return internal_error;
}
/*
* Format prompt string.
*/
for (i = 0; (i < 127) && (*fmt != '\0'); i++, fmt++)
if (*fmt == '\\')
switch (*++fmt) {
/*
* Hostname.
*
* \h specifies just the local hostname,
* \H specifies fully-qualified hostname.
*/
case 'h':
case 'H':
ps[i] = '\0';
gethostname(&ps[i], PROMPTLEN - i);
/* Skip to end of hostname. */
trim = (*fmt == 'h') ? '.' : '\0';
while ((ps[i+1] != '\0') && (ps[i+1] != trim))
i++;
break;
/*
* Working directory.
*
* \W specifies just the final component,
* \w specifies the entire path.
*/
case 'W':
case 'w':
pwd = lookupvar("PWD");
if (pwd == NULL)
pwd = "?";
if (*fmt == 'W' &&
*pwd == '/' && pwd[1] != '\0')
strlcpy(&ps[i], strrchr(pwd, '/') + 1,
PROMPTLEN - i);
else
strlcpy(&ps[i], pwd, PROMPTLEN - i);
/* Skip to end of path. */
while (ps[i + 1] != '\0')
i++;
break;
/*
* Superuser status.
*
* '$' for normal users, '#' for root.
*/
case '$':
ps[i] = (geteuid() != 0) ? '$' : '#';
break;
/*
* A literal \.
*/
case '\\':
ps[i] = '\\';
break;
/*
* Emit unrecognized formats verbatim.
*/
default:
ps[i++] = '\\';
ps[i] = *fmt;
break;
}
else
ps[i] = *fmt;
ps[i] = '\0';
return (ps);
}
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