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expand.c
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/* $NetBSD: expand.c,v 1.68.2.2 2005/04/07 11:37:39 tron Exp $ */
/*-
* 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.
* 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 <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)expand.c 8.5 (Berkeley) 5/15/95";
#else
__RCSID("$NetBSD: expand.c,v 1.68.2.2 2005/04/07 11:37:39 tron Exp $");
#endif
#endif /* not lint */
#include <sys/types.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <errno.h>
#include <dirent.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
/*
* Routines to expand arguments to commands. We have to deal with
* backquotes, shell variables, and file metacharacters.
*/
#include "shell.h"
#include "main.h"
#include "nodes.h"
#include "eval.h"
#include "expand.h"
#include "syntax.h"
#include "parser.h"
#include "jobs.h"
#include "options.h"
#include "var.h"
#include "input.h"
#include "output.h"
#include "memalloc.h"
#include "error.h"
#include "mystring.h"
#include "show.h"
/*
* Structure specifying which parts of the string should be searched
* for IFS characters.
*/
struct ifsregion {
struct ifsregion *next; /* next region in list */
int begoff; /* offset of start of region */
int endoff; /* offset of end of region */
int inquotes; /* search for nul bytes only */
};
char *expdest; /* output of current string */
struct nodelist *argbackq; /* list of back quote expressions */
struct ifsregion ifsfirst; /* first struct in list of ifs regions */
struct ifsregion *ifslastp; /* last struct in list */
struct arglist exparg; /* holds expanded arg list */
STATIC void argstr(char *, int);
STATIC char *exptilde(char *, int);
STATIC void expbackq(union node *, int, int);
STATIC int subevalvar(char *, char *, int, int, int, int);
STATIC char *evalvar(char *, int);
STATIC int varisset(char *, int);
STATIC void varvalue(char *, int, int, int);
STATIC void recordregion(int, int, int);
STATIC void removerecordregions(int);
STATIC void ifsbreakup(char *, struct arglist *);
STATIC void ifsfree(void);
STATIC void expandmeta(struct strlist *, int);
STATIC void expmeta(char *, char *);
STATIC void addfname(char *);
STATIC struct strlist *expsort(struct strlist *);
STATIC struct strlist *msort(struct strlist *, int);
STATIC int pmatch(char *, char *, int);
STATIC char *cvtnum(int, char *);
/*
* Expand shell variables and backquotes inside a here document.
*/
void
expandhere(union node *arg, int fd)
{
herefd = fd;
expandarg(arg, (struct arglist *)NULL, 0);
xwrite(fd, stackblock(), expdest - stackblock());
}
/*
* Perform variable substitution and command substitution on an argument,
* placing the resulting list of arguments in arglist. If EXP_FULL is true,
* perform splitting and file name expansion. When arglist is NULL, perform
* here document expansion.
*/
void
expandarg(union node *arg, struct arglist *arglist, int flag)
{
struct strlist *sp;
char *p;
argbackq = arg->narg.backquote;
STARTSTACKSTR(expdest);
ifsfirst.next = NULL;
ifslastp = NULL;
argstr(arg->narg.text, flag);
if (arglist == NULL) {
return; /* here document expanded */
}
STPUTC('\0', expdest);
p = grabstackstr(expdest);
exparg.lastp = &exparg.list;
/*
* TODO - EXP_REDIR
*/
if (flag & EXP_FULL) {
ifsbreakup(p, &exparg);
*exparg.lastp = NULL;
exparg.lastp = &exparg.list;
expandmeta(exparg.list, flag);
} else {
if (flag & EXP_REDIR) /*XXX - for now, just remove escapes */
rmescapes(p);
sp = (struct strlist *)stalloc(sizeof (struct strlist));
sp->text = p;
*exparg.lastp = sp;
exparg.lastp = &sp->next;
}
ifsfree();
*exparg.lastp = NULL;
if (exparg.list) {
*arglist->lastp = exparg.list;
arglist->lastp = exparg.lastp;
}
}
/*
* Perform variable and command substitution.
* If EXP_FULL is set, output CTLESC characters to allow for further processing.
* Otherwise treat $@ like $* since no splitting will be performed.
*/
STATIC void
argstr(char *p, int flag)
{
char c;
int quotes = flag & (EXP_FULL | EXP_CASE); /* do CTLESC */
int firsteq = 1;
const char *ifs = 0;
int ifs_split = EXP_IFS_SPLIT;
if (flag & EXP_IFS_SPLIT)
ifs = ifsset() ? ifsval() : " \t\n";
if (*p == '~' && (flag & (EXP_TILDE | EXP_VARTILDE)))
p = exptilde(p, flag);
for (;;) {
switch (c = *p++) {
case '\0':
case CTLENDVAR: /* end of expanding yyy in ${xxx-yyy} */
return;
case CTLQUOTEMARK:
/* "$@" syntax adherence hack */
if (p[0] == CTLVAR && p[2] == '@' && p[3] == '=')
break;
if ((flag & EXP_FULL) != 0)
STPUTC(c, expdest);
ifs_split = 0;
break;
case CTLQUOTEEND:
ifs_split = EXP_IFS_SPLIT;
break;
case CTLESC:
if (quotes)
STPUTC(c, expdest);
c = *p++;
STPUTC(c, expdest);
break;
case CTLVAR:
p = evalvar(p, (flag & ~EXP_IFS_SPLIT) | (flag & ifs_split));
break;
case CTLBACKQ:
case CTLBACKQ|CTLQUOTE:
expbackq(argbackq->n, c & CTLQUOTE, flag);
argbackq = argbackq->next;
break;
case CTLENDARI:
expari(flag);
break;
case ':':
case '=':
/*
* sort of a hack - expand tildes in variable
* assignments (after the first '=' and after ':'s).
*/
STPUTC(c, expdest);
if (flag & EXP_VARTILDE && *p == '~') {
if (c == '=') {
if (firsteq)
firsteq = 0;
else
break;
}
p = exptilde(p, flag);
}
break;
default:
STPUTC(c, expdest);
if (flag & EXP_IFS_SPLIT & ifs_split && strchr(ifs, c) != NULL) {
/* We need to get the output split here... */
recordregion(expdest - stackblock() - 1,
expdest - stackblock(), 0);
}
break;
}
}
}
STATIC char *
exptilde(char *p, int flag)
{
char c, *startp = p;
const char *home;
int quotes = flag & (EXP_FULL | EXP_CASE);
while ((c = *p) != '\0') {
switch(c) {
case CTLESC:
return (startp);
case CTLQUOTEMARK:
return (startp);
case ':':
if (flag & EXP_VARTILDE)
goto done;
break;
case '/':
goto done;
}
p++;
}
done:
*p = '\0';
if (*(startp+1) == '\0') {
if ((home = lookupvar("HOME")) == NULL)
goto lose;
} else
goto lose;
if (*home == '\0')
goto lose;
*p = c;
while ((c = *home++) != '\0') {
if (quotes && SQSYNTAX[(int)c] == CCTL)
STPUTC(CTLESC, expdest);
STPUTC(c, expdest);
}
return (p);
lose:
*p = c;
return (startp);
}
STATIC void
removerecordregions(int endoff)
{
if (ifslastp == NULL)
return;
if (ifsfirst.endoff > endoff) {
while (ifsfirst.next != NULL) {
struct ifsregion *ifsp;
INTOFF;
ifsp = ifsfirst.next->next;
ckfree(ifsfirst.next);
ifsfirst.next = ifsp;
INTON;
}
if (ifsfirst.begoff > endoff)
ifslastp = NULL;
else {
ifslastp = &ifsfirst;
ifsfirst.endoff = endoff;
}
return;
}
ifslastp = &ifsfirst;
while (ifslastp->next && ifslastp->next->begoff < endoff)
ifslastp=ifslastp->next;
while (ifslastp->next != NULL) {
struct ifsregion *ifsp;
INTOFF;
ifsp = ifslastp->next->next;
ckfree(ifslastp->next);
ifslastp->next = ifsp;
INTON;
}
if (ifslastp->endoff > endoff)
ifslastp->endoff = endoff;
}
/*
* Expand arithmetic expression. Backup to start of expression,
* evaluate, place result in (backed up) result, adjust string position.
*/
void
expari(int flag)
{
char *p, *start;
int result;
int begoff;
int quotes = flag & (EXP_FULL | EXP_CASE);
int quoted;
/* ifsfree(); */
/*
* This routine is slightly over-complicated for
* efficiency. First we make sure there is
* enough space for the result, which may be bigger
* than the expression if we add exponentation. Next we
* scan backwards looking for the start of arithmetic. If the
* next previous character is a CTLESC character, then we
* have to rescan starting from the beginning since CTLESC
* characters have to be processed left to right.
*/
#if INT_MAX / 1000000000 >= 10 || INT_MIN / 1000000000 <= -10
#error "integers with more than 10 digits are not supported"
#endif
CHECKSTRSPACE(12 - 2, expdest);
USTPUTC('\0', expdest);
start = stackblock();
p = expdest - 1;
while (*p != CTLARI && p >= start)
--p;
if (*p != CTLARI)
error("missing CTLARI (shouldn't happen)");
if (p > start && *(p-1) == CTLESC)
for (p = start; *p != CTLARI; p++)
if (*p == CTLESC)
p++;
if (p[1] == '"')
quoted=1;
else
quoted=0;
begoff = p - start;
removerecordregions(begoff);
if (quotes)
rmescapes(p+2);
result = arith(p+2);
fmtstr(p, 12, "%d", result);
while (*p++)
;
if (quoted == 0)
recordregion(begoff, p - 1 - start, 0);
result = expdest - p + 1;
STADJUST(-result, expdest);
}
/*
* Expand stuff in backwards quotes.
*/
STATIC void
expbackq(union node *cmd, int quoted, int flag)
{
struct backcmd in;
int i;
char buf[128];
char *p;
char *dest = expdest;
struct ifsregion saveifs, *savelastp;
struct nodelist *saveargbackq;
char lastc;
int startloc = dest - stackblock();
char const *syntax = quoted? DQSYNTAX : BASESYNTAX;
int saveherefd;
int quotes = flag & (EXP_FULL | EXP_CASE);
INTOFF;
saveifs = ifsfirst;
savelastp = ifslastp;
saveargbackq = argbackq;
saveherefd = herefd;
herefd = -1;
p = grabstackstr(dest);
evalbackcmd(cmd, &in);
ungrabstackstr(p, dest);
ifsfirst = saveifs;
ifslastp = savelastp;
argbackq = saveargbackq;
herefd = saveherefd;
p = in.buf;
lastc = '\0';
for (;;) {
if (--in.nleft < 0) {
if (in.fd < 0)
break;
while ((i = read(in.fd, buf, sizeof buf)) < 0 && errno == EINTR);
TRACE(("expbackq: read returns %d\n", i));
if (i <= 0)
break;
p = buf;
in.nleft = i - 1;
}
lastc = *p++;
if (lastc != '\0') {
if (quotes && syntax[(int)lastc] == CCTL)
STPUTC(CTLESC, dest);
STPUTC(lastc, dest);
}
}
/* Eat all trailing newlines */
p = stackblock() + startloc;
while (dest > p && dest[-1] == '\n')
STUNPUTC(dest);
if (in.fd >= 0)
close(in.fd);
if (in.buf)
ckfree(in.buf);
if (in.jp)
back_exitstatus = waitforjob(in.jp);
if (quoted == 0)
recordregion(startloc, dest - stackblock(), 0);
TRACE(("evalbackq: size=%d: \"%.*s\"\n",
(dest - stackblock()) - startloc,
(dest - stackblock()) - startloc,
stackblock() + startloc));
expdest = dest;
INTON;
}
STATIC int
subevalvar(char *p, char *str, int strloc, int subtype, int startloc, int varflags)
{
char *startp;
char *loc = NULL;
char *q;
int c = 0;
int saveherefd = herefd;
struct nodelist *saveargbackq = argbackq;
int amount;
herefd = -1;
argstr(p, 0);
STACKSTRNUL(expdest);
herefd = saveherefd;
argbackq = saveargbackq;
startp = stackblock() + startloc;
if (str == NULL)
str = stackblock() + strloc;
switch (subtype) {
case VSASSIGN:
setvar(str, startp, 0);
amount = startp - expdest;
STADJUST(amount, expdest);
varflags &= ~VSNUL;
if (c != 0)
*loc = c;
return 1;
case VSQUESTION:
if (*p != CTLENDVAR) {
outfmt(&errout, "%s\n", startp);
error((char *)NULL);
}
error("%.*s: parameter %snot set", p - str - 1,
str, (varflags & VSNUL) ? "null or "
: nullstr);
/* NOTREACHED */
case VSTRIMLEFT:
for (loc = startp; loc < str; loc++) {
c = *loc;
*loc = '\0';
if (patmatch(str, startp, varflags & VSQUOTE))
goto recordleft;
*loc = c;
if ((varflags & VSQUOTE) && *loc == CTLESC)
loc++;
}
return 0;
case VSTRIMLEFTMAX:
for (loc = str - 1; loc >= startp;) {
c = *loc;
*loc = '\0';
if (patmatch(str, startp, varflags & VSQUOTE))
goto recordleft;
*loc = c;
loc--;
if ((varflags & VSQUOTE) && loc > startp &&
*(loc - 1) == CTLESC) {
for (q = startp; q < loc; q++)
if (*q == CTLESC)
q++;
if (q > loc)
loc--;
}
}
return 0;
case VSTRIMRIGHT:
for (loc = str - 1; loc >= startp;) {
if (patmatch(str, loc, varflags & VSQUOTE))
goto recordright;
loc--;
if ((varflags & VSQUOTE) && loc > startp &&
*(loc - 1) == CTLESC) {
for (q = startp; q < loc; q++)
if (*q == CTLESC)
q++;
if (q > loc)
loc--;
}
}
return 0;
case VSTRIMRIGHTMAX:
for (loc = startp; loc < str - 1; loc++) {
if (patmatch(str, loc, varflags & VSQUOTE))
goto recordright;
if ((varflags & VSQUOTE) && *loc == CTLESC)
loc++;
}
return 0;
default:
abort();
}
recordleft:
*loc = c;
amount = ((str - 1) - (loc - startp)) - expdest;
STADJUST(amount, expdest);
while (loc != str - 1)
*startp++ = *loc++;
return 1;
recordright:
amount = loc - expdest;
STADJUST(amount, expdest);
STPUTC('\0', expdest);
STADJUST(-1, expdest);
return 1;
}
/*
* Expand a variable, and return a pointer to the next character in the
* input string.
*/
STATIC char *
evalvar(char *p, int flag)
{
int subtype;
int varflags;
char *var;
char *val;
int patloc;
int c;
int set;
int special;
int startloc;
int varlen;
int apply_ifs;
int quotes = flag & (EXP_FULL | EXP_CASE);
varflags = (unsigned char)*p++;
subtype = varflags & VSTYPE;
var = p;
special = !is_name(*p);
p = strchr(p, '=') + 1;
again: /* jump here after setting a variable with ${var=text} */
if (special) {
set = varisset(var, varflags & VSNUL);
val = NULL;
} else {
val = lookupvar(var);
if (val == NULL || ((varflags & VSNUL) && val[0] == '\0')) {
val = NULL;
set = 0;
} else
set = 1;
}
varlen = 0;
startloc = expdest - stackblock();
if (!set && uflag) {
switch (subtype) {
case VSNORMAL:
case VSTRIMLEFT:
case VSTRIMLEFTMAX:
case VSTRIMRIGHT:
case VSTRIMRIGHTMAX:
case VSLENGTH:
error("%.*s: parameter not set", p - var - 1, var);
/* NOTREACHED */
}
}
if (set && subtype != VSPLUS) {
/* insert the value of the variable */
if (special) {
varvalue(var, varflags & VSQUOTE, subtype, flag);
if (subtype == VSLENGTH) {
varlen = expdest - stackblock() - startloc;
STADJUST(-varlen, expdest);
}
} else {
char const *syntax = (varflags & VSQUOTE) ? DQSYNTAX
: BASESYNTAX;
if (subtype == VSLENGTH) {
for (;*val; val++)
varlen++;
} else {
while (*val) {
if (quotes && syntax[(int)*val] == CCTL)
STPUTC(CTLESC, expdest);
STPUTC(*val++, expdest);
}
}
}
}
apply_ifs = ((varflags & VSQUOTE) == 0 ||
(*var == '@' && shellparam.nparam != 1));
switch (subtype) {
case VSLENGTH:
expdest = cvtnum(varlen, expdest);
break;
case VSNORMAL:
break;
case VSPLUS:
set = !set;
/* FALLTHROUGH */
case VSMINUS:
if (!set) {
argstr(p, flag | (apply_ifs ? EXP_IFS_SPLIT : 0));
/*
* ${x-a b c} doesn't get split, but removing the
* 'apply_ifs = 0' apparantly breaks ${1+"$@"}..
* ${x-'a b' c} should generate 2 args.
*/
/* We should have marked stuff already */
apply_ifs = 0;
}
break;
case VSTRIMLEFT:
case VSTRIMLEFTMAX:
case VSTRIMRIGHT:
case VSTRIMRIGHTMAX:
if (!set)
break;
/*
* Terminate the string and start recording the pattern
* right after it
*/
STPUTC('\0', expdest);
patloc = expdest - stackblock();
if (subevalvar(p, NULL, patloc, subtype,
startloc, varflags) == 0) {
int amount = (expdest - stackblock() - patloc) + 1;
STADJUST(-amount, expdest);
}
/* Remove any recorded regions beyond start of variable */
removerecordregions(startloc);
apply_ifs = 1;
break;
case VSASSIGN:
case VSQUESTION:
if (set)
break;
if (subevalvar(p, var, 0, subtype, startloc, varflags)) {
varflags &= ~VSNUL;
/*
* Remove any recorded regions beyond
* start of variable
*/
removerecordregions(startloc);
goto again;
}
apply_ifs = 0;
break;
default:
abort();
}
if (apply_ifs)
recordregion(startloc, expdest - stackblock(),
varflags & VSQUOTE);
if (subtype != VSNORMAL) { /* skip to end of alternative */
int nesting = 1;
for (;;) {
if ((c = *p++) == CTLESC)
p++;
else if (c == CTLBACKQ || c == (CTLBACKQ|CTLQUOTE)) {
if (set)
argbackq = argbackq->next;
} else if (c == CTLVAR) {
if ((*p++ & VSTYPE) != VSNORMAL)
nesting++;
} else if (c == CTLENDVAR) {
if (--nesting == 0)
break;
}
}
}
return p;
}
/*
* Test whether a specialized variable is set.
*/
STATIC int
varisset(char *name, int nulok)
{
if (*name == '!')
return backgndpid != -1;
else if (*name == '@' || *name == '*') {
if (*shellparam.p == NULL)
return 0;
if (nulok) {
char **av;
for (av = shellparam.p; *av; av++)
if (**av != '\0')
return 1;
return 0;
}
} else if (is_digit(*name)) {
char *ap;
int num = atoi(name);
if (num > shellparam.nparam)
return 0;
if (num == 0)
ap = arg0;
else
ap = shellparam.p[num - 1];
if (nulok && (ap == NULL || *ap == '\0'))
return 0;
}
return 1;
}
/*
* Add the value of a specialized variable to the stack string.
*/
STATIC void
varvalue(char *name, int quoted, int subtype, int flag)
{
int num;
char *p;
int i;
char sep;
char **ap;
char const *syntax;
#define STRTODEST(p) \
do {\
if (flag & (EXP_FULL | EXP_CASE) && subtype != VSLENGTH) { \
syntax = quoted? DQSYNTAX : BASESYNTAX; \
while (*p) { \
if (syntax[(int)*p] == CCTL) \
STPUTC(CTLESC, expdest); \
STPUTC(*p++, expdest); \
} \
} else \
while (*p) \
STPUTC(*p++, expdest); \
} while (0)
switch (*name) {
case '$':
num = rootpid;
goto numvar;
case '?':
num = exitstatus;
goto numvar;
case '#':
num = shellparam.nparam;
goto numvar;
case '!':
num = backgndpid;
numvar:
expdest = cvtnum(num, expdest);
break;
case '-':
for (i = 0; optlist[i].name; i++) {
if (optlist[i].val)
STPUTC(optlist[i].letter, expdest);
}
break;
case '@':
if (flag & EXP_FULL && quoted) {
for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
STRTODEST(p);
if (*ap)
STPUTC('\0', expdest);
}
break;
}
/* fall through */
case '*':
if (ifsset() != 0)
sep = ifsval()[0];
else
sep = ' ';
for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
STRTODEST(p);
if (*ap && sep)
STPUTC(sep, expdest);
}
break;
case '0':
p = arg0;
STRTODEST(p);
break;
default:
if (is_digit(*name)) {
num = atoi(name);
if (num > 0 && num <= shellparam.nparam) {
p = shellparam.p[num - 1];
STRTODEST(p);
}
}
break;
}
}
/*
* Record the fact that we have to scan this region of the
* string for IFS characters.
*/
STATIC void
recordregion(int start, int end, int inquotes)
{
struct ifsregion *ifsp;
if (ifslastp == NULL) {
ifsp = &ifsfirst;
} else {
if (ifslastp->endoff == start
&& ifslastp->inquotes == inquotes) {
/* extend previous area */
ifslastp->endoff = end;
return;
}
ifsp = (struct ifsregion *)ckmalloc(sizeof (struct ifsregion));
ifslastp->next = ifsp;
}
ifslastp = ifsp;
ifslastp->next = NULL;
ifslastp->begoff = start;
ifslastp->endoff = end;
ifslastp->inquotes = inquotes;
}
/*
* Break the argument string into pieces based upon IFS and add the
* strings to the argument list. The regions of the string to be
* searched for IFS characters have been stored by recordregion.
*/
STATIC void
ifsbreakup(char *string, struct arglist *arglist)
{
struct ifsregion *ifsp;
struct strlist *sp;
char *start;
char *p;
char *q;
const char *ifs;
const char *ifsspc;
int inquotes;
start = string;
ifsspc = NULL;
inquotes = 0;
if (ifslastp == NULL) {
/* Return entire argument, IFS doesn't apply to any of it */
sp = (struct strlist *)stalloc(sizeof *sp);
sp->text = start;
*arglist->lastp = sp;
arglist->lastp = &sp->next;
return;
}
ifs = ifsset() ? ifsval() : " \t\n";
for (ifsp = &ifsfirst; ifsp != NULL; ifsp = ifsp->next) {
p = string + ifsp->begoff;
inquotes = ifsp->inquotes;
ifsspc = NULL;
while (p < string + ifsp->endoff) {
q = p;
if (*p == CTLESC)
p++;
if (inquotes) {
/* Only NULs (probably from "$@") end args */
if (*p != 0) {
p++;
continue;
}
} else {
if (!strchr(ifs, *p)) {
p++;
continue;
}
ifsspc = strchr(" \t\n", *p);
/* Ignore IFS whitespace at start */
if (q == start && ifsspc != NULL) {
p++;
start = p;
continue;
}
}
/* Save this argument... */
*q = '\0';