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eval.c
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eval.c
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/* $NetBSD: eval.c,v 1.81.2.1 2005/06/13 22:03:51 tron Exp $ */
/*-
* Copyright (c) 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[] = "@(#)eval.c 8.9 (Berkeley) 6/8/95";
#else
__RCSID("$NetBSD: eval.c,v 1.81.2.1 2005/06/13 22:03:51 tron Exp $");
#endif
#endif /* not lint */
#include <stdlib.h>
#include <signal.h>
#include <stdio.h>
#include <unistd.h>
#ifdef __linux__
#include <fcntl.h>
#else
#include <sys/fcntl.h>
#endif
#include <sys/times.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/wait.h>
/*
* Evaluate a command.
*/
#include "shell.h"
#include "nodes.h"
#include "syntax.h"
#include "expand.h"
#include "parser.h"
#include "jobs.h"
#include "eval.h"
#include "builtins.h"
#include "options.h"
#include "exec.h"
#include "redir.h"
#include "input.h"
#include "output.h"
#include "trap.h"
#include "var.h"
#include "memalloc.h"
#include "error.h"
#include "show.h"
#include "mystring.h"
#include "main.h"
#ifndef SMALL
#include "myhistedit.h"
#endif
/* flags in argument to evaltree */
#define EV_EXIT 01 /* exit after evaluating tree */
#define EV_TESTED 02 /* exit status is checked; ignore -e flag */
#define EV_BACKCMD 04 /* command executing within back quotes */
int evalskip; /* set if we are skipping commands */
STATIC int skipcount; /* number of levels to skip */
MKINIT int loopnest; /* current loop nesting level */
int funcnest; /* depth of function calls */
char *commandname;
struct strlist *cmdenviron;
int exitstatus; /* exit status of last command */
int back_exitstatus; /* exit status of backquoted command */
STATIC void evalloop(union node *, int);
STATIC void evalfor(union node *, int);
STATIC void evalcase(union node *, int);
STATIC void evalsubshell(union node *, int);
STATIC void expredir(union node *);
STATIC void evalpipe(union node *);
STATIC void evalcommand(union node *, int, struct backcmd *);
STATIC void prehash(union node *);
/*
* Called to reset things after an exception.
*/
#ifdef mkinit
INCLUDE "eval.h"
RESET {
evalskip = 0;
loopnest = 0;
funcnest = 0;
}
SHELLPROC {
exitstatus = 0;
}
#endif
static int
sh_pipe(int fds[2])
{
int nfd;
if (pipe(fds))
return -1;
if (fds[0] < 3) {
nfd = fcntl(fds[0], F_DUPFD, 3);
if (nfd != -1) {
close(fds[0]);
fds[0] = nfd;
}
}
if (fds[1] < 3) {
nfd = fcntl(fds[1], F_DUPFD, 3);
if (nfd != -1) {
close(fds[1]);
fds[1] = nfd;
}
}
return 0;
}
/*
* The eval commmand.
*/
int
evalcmd(int argc, char **argv)
{
char *p;
char *concat;
char **ap;
if (argc > 1) {
p = argv[1];
if (argc > 2) {
STARTSTACKSTR(concat);
ap = argv + 2;
for (;;) {
while (*p)
STPUTC(*p++, concat);
if ((p = *ap++) == NULL)
break;
STPUTC(' ', concat);
}
STPUTC('\0', concat);
p = grabstackstr(concat);
}
evalstring(p, EV_TESTED);
}
return exitstatus;
}
/*
* Execute a command or commands contained in a string.
*/
void
evalstring(char *s, int flag)
{
union node *n;
struct stackmark smark;
setstackmark(&smark);
setinputstring(s, 1);
while ((n = parsecmd(0)) != NEOF) {
evaltree(n, flag);
popstackmark(&smark);
}
popfile();
popstackmark(&smark);
}
/*
* Evaluate a parse tree. The value is left in the global variable
* exitstatus.
*/
void
evaltree(union node *n, int flags)
{
if (n == NULL) {
TRACE(("evaltree(NULL) called\n"));
exitstatus = 0;
goto out;
}
#ifdef WITH_HISTORY
displayhist = 1; /* show history substitutions done with fc */
#endif
TRACE(("pid %d, evaltree(%p: %d, %d) called\n",
getpid(), n, n->type, flags));
switch (n->type) {
case NSEMI:
evaltree(n->nbinary.ch1, flags & EV_TESTED);
if (evalskip)
goto out;
evaltree(n->nbinary.ch2, flags);
break;
case NAND:
evaltree(n->nbinary.ch1, EV_TESTED);
if (evalskip || exitstatus != 0)
goto out;
evaltree(n->nbinary.ch2, flags);
break;
case NOR:
evaltree(n->nbinary.ch1, EV_TESTED);
if (evalskip || exitstatus == 0)
goto out;
evaltree(n->nbinary.ch2, flags);
break;
case NREDIR:
expredir(n->nredir.redirect);
redirect(n->nredir.redirect, REDIR_PUSH);
evaltree(n->nredir.n, flags);
popredir();
break;
case NSUBSHELL:
evalsubshell(n, flags);
break;
case NBACKGND:
evalsubshell(n, flags);
break;
case NIF: {
evaltree(n->nif.test, EV_TESTED);
if (evalskip)
goto out;
if (exitstatus == 0)
evaltree(n->nif.ifpart, flags);
else if (n->nif.elsepart)
evaltree(n->nif.elsepart, flags);
else
exitstatus = 0;
break;
}
case NWHILE:
case NUNTIL:
evalloop(n, flags);
break;
case NFOR:
evalfor(n, flags);
break;
case NCASE:
evalcase(n, flags);
break;
case NDEFUN:
defun(n->narg.text, n->narg.next);
exitstatus = 0;
break;
case NNOT:
evaltree(n->nnot.com, EV_TESTED);
exitstatus = !exitstatus;
break;
case NPIPE:
evalpipe(n);
break;
case NCMD:
evalcommand(n, flags, (struct backcmd *)NULL);
break;
default:
out1fmt("Node type = %d\n", n->type);
flushout(&output);
break;
}
out:
if (pendingsigs)
dotrap();
if ((flags & EV_EXIT) != 0)
exitshell(exitstatus);
}
STATIC void
evalloop(union node *n, int flags)
{
int status;
loopnest++;
status = 0;
for (;;) {
evaltree(n->nbinary.ch1, EV_TESTED);
if (evalskip) {
skipping: if (evalskip == SKIPCONT && --skipcount <= 0) {
evalskip = 0;
continue;
}
if (evalskip == SKIPBREAK && --skipcount <= 0)
evalskip = 0;
break;
}
if (n->type == NWHILE) {
if (exitstatus != 0)
break;
} else {
if (exitstatus == 0)
break;
}
evaltree(n->nbinary.ch2, flags & EV_TESTED);
status = exitstatus;
if (evalskip)
goto skipping;
}
loopnest--;
exitstatus = status;
}
STATIC void
evalfor(union node *n, int flags)
{
struct arglist arglist;
union node *argp;
struct strlist *sp;
struct stackmark smark;
int status = 0;
setstackmark(&smark);
arglist.lastp = &arglist.list;
for (argp = n->nfor.args ; argp ; argp = argp->narg.next) {
expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
if (evalskip)
goto out;
}
*arglist.lastp = NULL;
loopnest++;
for (sp = arglist.list ; sp ; sp = sp->next) {
setvar(n->nfor.var, sp->text, 0);
evaltree(n->nfor.body, flags & EV_TESTED);
status = exitstatus;
if (evalskip) {
if (evalskip == SKIPCONT && --skipcount <= 0) {
evalskip = 0;
continue;
}
if (evalskip == SKIPBREAK && --skipcount <= 0)
evalskip = 0;
break;
}
}
loopnest--;
exitstatus = status;
out:
popstackmark(&smark);
}
STATIC void
evalcase(union node *n, int flags)
{
union node *cp;
union node *patp;
struct arglist arglist;
struct stackmark smark;
int status = 0;
setstackmark(&smark);
arglist.lastp = &arglist.list;
expandarg(n->ncase.expr, &arglist, EXP_TILDE);
for (cp = n->ncase.cases ; cp && evalskip == 0 ; cp = cp->nclist.next) {
for (patp = cp->nclist.pattern ; patp ; patp = patp->narg.next) {
if (casematch(patp, arglist.list->text)) {
if (evalskip == 0) {
evaltree(cp->nclist.body, flags);
status = exitstatus;
}
goto out;
}
}
}
out:
exitstatus = status;
popstackmark(&smark);
}
/*
* Kick off a subshell to evaluate a tree.
*/
STATIC void
evalsubshell(union node *n, int flags)
{
struct job *jp;
int backgnd = (n->type == NBACKGND);
expredir(n->nredir.redirect);
INTOFF;
jp = makejob(n, 1);
if (forkshell(jp, n, backgnd) == 0) {
INTON;
if (backgnd)
flags &=~ EV_TESTED;
redirect(n->nredir.redirect, 0);
/* never returns */
evaltree(n->nredir.n, flags | EV_EXIT);
}
if (! backgnd)
exitstatus = waitforjob(jp);
INTON;
}
/*
* Compute the names of the files in a redirection list.
*/
STATIC void
expredir(union node *n)
{
union node *redir;
for (redir = n ; redir ; redir = redir->nfile.next) {
struct arglist fn;
fn.lastp = &fn.list;
switch (redir->type) {
case NFROMTO:
case NFROM:
case NTO:
case NCLOBBER:
case NAPPEND:
expandarg(redir->nfile.fname, &fn, EXP_TILDE | EXP_REDIR);
redir->nfile.expfname = fn.list->text;
break;
case NFROMFD:
case NTOFD:
if (redir->ndup.vname) {
expandarg(redir->ndup.vname, &fn, EXP_FULL | EXP_TILDE);
fixredir(redir, fn.list->text, 1);
}
break;
}
}
}
/*
* Evaluate a pipeline. All the processes in the pipeline are children
* of the process creating the pipeline. (This differs from some versions
* of the shell, which make the last process in a pipeline the parent
* of all the rest.)
*/
STATIC void
evalpipe(union node *n)
{
struct job *jp;
struct nodelist *lp;
int pipelen;
int prevfd;
int pip[2];
TRACE(("evalpipe(0x%lx) called\n", (long)n));
pipelen = 0;
for (lp = n->npipe.cmdlist ; lp ; lp = lp->next)
pipelen++;
INTOFF;
jp = makejob(n, pipelen);
prevfd = -1;
for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
prehash(lp->n);
pip[1] = -1;
if (lp->next) {
if (sh_pipe(pip) < 0) {
close(prevfd);
error("Pipe call failed");
}
}
if (forkshell(jp, lp->n, n->npipe.backgnd) == 0) {
INTON;
if (prevfd > 0) {
close(0);
copyfd(prevfd, 0);
close(prevfd);
}
if (pip[1] >= 0) {
close(pip[0]);
if (pip[1] != 1) {
close(1);
copyfd(pip[1], 1);
close(pip[1]);
}
}
evaltree(lp->n, EV_EXIT);
}
if (prevfd >= 0)
close(prevfd);
prevfd = pip[0];
close(pip[1]);
}
if (n->npipe.backgnd == 0) {
exitstatus = waitforjob(jp);
TRACE(("evalpipe: job done exit status %d\n", exitstatus));
}
INTON;
}
/*
* Execute a command inside back quotes. If it's a builtin command, we
* want to save its output in a block obtained from malloc. Otherwise
* we fork off a subprocess and get the output of the command via a pipe.
* Should be called with interrupts off.
*/
void
evalbackcmd(union node *n, struct backcmd *result)
{
int pip[2];
struct job *jp;
struct stackmark smark; /* unnecessary */
setstackmark(&smark);
result->fd = -1;
result->buf = NULL;
result->nleft = 0;
result->jp = NULL;
if (n == NULL) {
goto out;
}
#ifdef notyet
/*
* For now we disable executing builtins in the same
* context as the shell, because we are not keeping
* enough state to recover from changes that are
* supposed only to affect subshells. eg. echo "`cd /`"
*/
if (n->type == NCMD) {
exitstatus = oexitstatus;
evalcommand(n, EV_BACKCMD, result);
} else
#endif
{
INTOFF;
if (sh_pipe(pip) < 0)
error("Pipe call failed");
jp = makejob(n, 1);
if (forkshell(jp, n, FORK_NOJOB) == 0) {
FORCEINTON;
close(pip[0]);
if (pip[1] != 1) {
close(1);
copyfd(pip[1], 1);
close(pip[1]);
}
eflag = 0;
evaltree(n, EV_EXIT);
/* NOTREACHED */
}
close(pip[1]);
result->fd = pip[0];
result->jp = jp;
INTON;
}
out:
popstackmark(&smark);
TRACE(("evalbackcmd done: fd=%d buf=0x%x nleft=%d jp=0x%x\n",
result->fd, result->buf, result->nleft, result->jp));
}
static const char *
syspath(void)
{
static char *sys_path = NULL;
#ifndef __linux__
static int mib[] = {CTL_USER, USER_CS_PATH};
#endif
static char def_path[] = "PATH=/usr/bin:/bin:/usr/sbin:/sbin";
if (sys_path == NULL) {
#ifndef __linux__
size_t len;
if (sysctl(mib, 2, 0, &len, 0, 0) != -1 &&
(sys_path = ckmalloc(len + 5)) != NULL &&
sysctl(mib, 2, sys_path + 5, &len, 0, 0) != -1) {
memcpy(sys_path, "PATH=", 5);
} else
#endif
{
ckfree(sys_path);
/* something to keep things happy */
sys_path = def_path;
}
}
return sys_path;
}
static int
parse_command_args(int argc, char **argv, int *use_syspath)
{
int sv_argc = argc;
char *cp, c;
*use_syspath = 0;
for (;;) {
argv++;
if (--argc == 0)
break;
cp = *argv;
if (*cp++ != '-')
break;
if (*cp == '-' && cp[1] == 0) {
argv++;
argc--;
break;
}
while ((c = *cp++)) {
switch (c) {
case 'p':
*use_syspath = 1;
break;
default:
/* run 'typecmd' for other options */
return 0;
}
}
}
return sv_argc - argc;
}
int vforked = 0;
/*
* Execute a simple command.
*/
STATIC void
evalcommand(union node *cmd, int flags, struct backcmd *backcmd)
{
struct stackmark smark;
union node *argp;
struct arglist arglist;
struct arglist varlist;
char **argv;
int argc;
char **envp;
int varflag;
struct strlist *sp;
int mode;
int pip[2];
struct cmdentry cmdentry;
struct job *jp;
struct jmploc jmploc;
struct jmploc *volatile savehandler = 0;
char *volatile savecmdname;
volatile struct shparam saveparam;
struct localvar *volatile savelocalvars;
volatile int e;
char *lastarg;
const char *path = pathval();
volatile int temp_path = 0;
#if __GNUC__
/* Avoid longjmp clobbering */
(void) &argv;
(void) &argc;
(void) &lastarg;
(void) &flags;
#endif
vforked = 0;
/* First expand the arguments. */
TRACE(("evalcommand(0x%lx, %d) called\n", (long)cmd, flags));
setstackmark(&smark);
back_exitstatus = 0;
arglist.lastp = &arglist.list;
varflag = 1;
/* Expand arguments, ignoring the initial 'name=value' ones */
for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) {
char *p = argp->narg.text;
if (varflag && is_name(*p)) {
do {
p++;
} while (is_in_name(*p));
if (*p == '=')
continue;
}
expandarg(argp, &arglist, EXP_FULL | EXP_TILDE);
varflag = 0;
}
*arglist.lastp = NULL;
expredir(cmd->ncmd.redirect);
/* Now do the initial 'name=value' ones we skipped above */
varlist.lastp = &varlist.list;
for (argp = cmd->ncmd.args ; argp ; argp = argp->narg.next) {
char *p = argp->narg.text;
if (!is_name(*p))
break;
do
p++;
while (is_in_name(*p));
if (*p != '=')
break;
expandarg(argp, &varlist, EXP_VARTILDE);
}
*varlist.lastp = NULL;
argc = 0;
for (sp = arglist.list ; sp ; sp = sp->next)
argc++;
argv = stalloc(sizeof (char *) * (argc + 1));
for (sp = arglist.list ; sp ; sp = sp->next) {
TRACE(("evalcommand arg: %s\n", sp->text));
*argv++ = sp->text;
}
*argv = NULL;
lastarg = NULL;
if (iflag && funcnest == 0 && argc > 0)
lastarg = argv[-1];
argv -= argc;
/* Print the command if xflag is set. */
if (xflag) {
char sep = 0;
out2str(ps4val());
for (sp = varlist.list ; sp ; sp = sp->next) {
if (sep != 0)
outc(sep, &errout);
out2str(sp->text);
sep = ' ';
}
for (sp = arglist.list ; sp ; sp = sp->next) {
if (sep != 0)
outc(sep, &errout);
out2str(sp->text);
sep = ' ';
}
outc('\n', &errout);
flushout(&errout);
}
/* Now locate the command. */
if (argc == 0) {
cmdentry.cmdtype = CMDSPLBLTIN;
cmdentry.u.bltin = bltincmd;
} else {
static const char PATH[] = "PATH=";
int cmd_flags = DO_ERR;
/*
* Modify the command lookup path, if a PATH= assignment
* is present
*/
for (sp = varlist.list; sp; sp = sp->next)
if (strncmp(sp->text, PATH, sizeof(PATH) - 1) == 0)
path = sp->text + sizeof(PATH) - 1;
do {
int argsused, use_syspath;
find_command(argv[0], &cmdentry, cmd_flags, path);
if (cmdentry.cmdtype == CMDUNKNOWN) {
exitstatus = 127;
flushout(&errout);
goto out;
}
/* implement the 'command' builtin here */
if (cmdentry.cmdtype != CMDBUILTIN ||
cmdentry.u.bltin != bltincmd)
break;
cmd_flags |= DO_NOFUNC;
argsused = parse_command_args(argc, argv, &use_syspath);
if (argsused == 0) {
/* use 'type' builting to display info */
cmdentry.u.bltin = typecmd;
break;
}
argc -= argsused;
argv += argsused;
if (use_syspath)
path = syspath() + 5;
} while (argc != 0);
if (cmdentry.cmdtype == CMDSPLBLTIN && cmd_flags & DO_NOFUNC)
/* posix mandates that 'command <splbltin>' act as if
<splbltin> was a normal builtin */
cmdentry.cmdtype = CMDBUILTIN;
}
/* Fork off a child process if necessary. */
if (cmd->ncmd.backgnd
|| (cmdentry.cmdtype == CMDNORMAL && (flags & EV_EXIT) == 0)
|| ((flags & EV_BACKCMD) != 0
&& ((cmdentry.cmdtype != CMDBUILTIN && cmdentry.cmdtype != CMDSPLBLTIN)
|| cmdentry.u.bltin == dotcmd
|| cmdentry.u.bltin == evalcmd))) {
INTOFF;
jp = makejob(cmd, 1);
mode = cmd->ncmd.backgnd;
if (flags & EV_BACKCMD) {
mode = FORK_NOJOB;
if (sh_pipe(pip) < 0)
error("Pipe call failed");
}
#ifdef DO_SHAREDVFORK
/* It is essential that if DO_SHAREDVFORK is defined that the
* child's address space is actually shared with the parent as
* we rely on this.
*/
if (cmdentry.cmdtype == CMDNORMAL) {
pid_t pid;
savelocalvars = localvars;
localvars = NULL;
vforked = 1;
switch (pid = vfork()) {
case -1:
TRACE(("Vfork failed, errno=%d\n", errno));
INTON;
error("Cannot vfork");
break;
case 0:
/* Make sure that exceptions only unwind to
* after the vfork(2)
*/
if (setjmp(jmploc.loc)) {
if (exception == EXSHELLPROC) {
/* We can't progress with the vfork,
* so, set vforked = 2 so the parent
* knows, and _exit();
*/
vforked = 2;
_exit(0);
} else {
_exit(exerrno);
}
}
savehandler = handler;
handler = &jmploc;
listmklocal(varlist.list, VEXPORT | VNOFUNC);
forkchild(jp, cmd, mode, vforked);
break;
default:
handler = savehandler; /* restore from vfork(2) */
poplocalvars();
localvars = savelocalvars;
if (vforked == 2) {
vforked = 0;
(void)waitpid(pid, NULL, 0);
/* We need to progress in a normal fork fashion */
goto normal_fork;
}
vforked = 0;
forkparent(jp, cmd, mode, pid);
goto parent;
}
} else {
normal_fork:
#endif
if (forkshell(jp, cmd, mode) != 0)
goto parent; /* at end of routine */
FORCEINTON;
#ifdef DO_SHAREDVFORK
}
#endif
if (flags & EV_BACKCMD) {
if (!vforked) {
FORCEINTON;
}
close(pip[0]);
if (pip[1] != 1) {
close(1);
copyfd(pip[1], 1);
close(pip[1]);
}
}
flags |= EV_EXIT;
}
/* This is the child process if a fork occurred. */
/* Execute the command. */
switch (cmdentry.cmdtype) {
case CMDFUNCTION:
#ifdef DEBUG
trputs("Shell function: "); trargs(argv);
#endif
redirect(cmd->ncmd.redirect, REDIR_PUSH);
saveparam = shellparam;
shellparam.malloc = 0;
shellparam.reset = 1;
shellparam.nparam = argc - 1;
shellparam.p = argv + 1;
shellparam.optnext = NULL;
INTOFF;
savelocalvars = localvars;
localvars = NULL;
INTON;
if (setjmp(jmploc.loc)) {
if (exception == EXSHELLPROC) {
freeparam((volatile struct shparam *)
&saveparam);
} else {
freeparam(&shellparam);
shellparam = saveparam;
}
poplocalvars();
localvars = savelocalvars;
handler = savehandler;
longjmp(handler->loc, 1);
}
savehandler = handler;
handler = &jmploc;
listmklocal(varlist.list, 0);
/* stop shell blowing its stack */
if (++funcnest > 1000)
error("too many nested function calls");
evaltree(cmdentry.u.func, flags & EV_TESTED);
funcnest--;
INTOFF;
poplocalvars();
localvars = savelocalvars;
freeparam(&shellparam);
shellparam = saveparam;
handler = savehandler;
popredir();
INTON;
if (evalskip == SKIPFUNC) {
evalskip = 0;
skipcount = 0;
}
if (flags & EV_EXIT)
exitshell(exitstatus);
break;
case CMDBUILTIN:
case CMDSPLBLTIN:
#ifdef DEBUG
trputs("builtin command: "); trargs(argv);
#endif
mode = (cmdentry.u.bltin == execcmd) ? 0 : REDIR_PUSH;
if (flags == EV_BACKCMD) {
memout.nleft = 0;
memout.nextc = memout.buf;
memout.bufsize = 64;
mode |= REDIR_BACKQ;
}
e = -1;
savehandler = handler;
savecmdname = commandname;
handler = &jmploc;
if (!setjmp(jmploc.loc)) {
/* We need to ensure the command hash table isn't
* corruped by temporary PATH assignments.
* However we must ensure the 'local' command works!
*/
if (path != pathval() && (cmdentry.u.bltin == hashcmd ||
cmdentry.u.bltin == typecmd)) {
savelocalvars = localvars;
localvars = 0;
mklocal(path - 5 /* PATH= */, 0);
temp_path = 1;