| Current Path : /compat/linux/proc/68247/root/usr/src/release/picobsd/tinyware/msh/ |
FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //compat/linux/proc/68247/root/usr/src/release/picobsd/tinyware/msh/sh3.c |
#define Extern extern
#include <sys/types.h>
#include <signal.h>
#define _NSIG NSIG
#include <errno.h>
#include <setjmp.h>
#include <stddef.h>
#include <time.h>
#include <sys/times.h>
#include <sys/stat.h>
#include <sys/wait.h>
#undef NULL
#include "sh.h"
/* -------- exec.c -------- */
/* #include "sh.h" */
/*
* execute tree
*/
static char *signame[] = {
"Signal 0",
"Hangup",
(char *)NULL, /* interrupt */
"Quit",
"Illegal instruction",
"Trace/BPT trap",
"Abort",
"EMT trap",
"Floating exception",
"Killed",
"Bus error",
"Memory fault",
"Bad system call",
(char *)NULL, /* broken pipe */
"Alarm clock",
"Terminated",
};
#define NSIGNAL (sizeof(signame)/sizeof(signame[0]))
_PROTOTYPE(static int forkexec, (struct op *t, int *pin, int *pout, int act, char **wp, int *pforked ));
_PROTOTYPE(static int parent, (void));
_PROTOTYPE(int iosetup, (struct ioword *iop, int pipein, int pipeout ));
_PROTOTYPE(static void echo, (char **wp ));
_PROTOTYPE(static struct op **find1case, (struct op *t, char *w ));
_PROTOTYPE(static struct op *findcase, (struct op *t, char *w ));
_PROTOTYPE(static void brkset, (struct brkcon *bc ));
_PROTOTYPE(int dolabel, (void));
_PROTOTYPE(int dochdir, (struct op *t ));
_PROTOTYPE(int doshift, (struct op *t ));
_PROTOTYPE(int dologin, (struct op *t ));
_PROTOTYPE(int doumask, (struct op *t ));
_PROTOTYPE(int doexec, (struct op *t ));
_PROTOTYPE(int dodot, (struct op *t ));
_PROTOTYPE(int dowait, (struct op *t ));
_PROTOTYPE(int doread, (struct op *t ));
_PROTOTYPE(int doeval, (struct op *t ));
_PROTOTYPE(int dotrap, (struct op *t ));
_PROTOTYPE(int getsig, (char *s ));
_PROTOTYPE(void setsig, (int n, void (*f)()));
_PROTOTYPE(int getn, (char *as ));
_PROTOTYPE(int dobreak, (struct op *t ));
_PROTOTYPE(int docontinue, (struct op *t ));
_PROTOTYPE(static int brkcontin, (char *cp, int val ));
_PROTOTYPE(int doexit, (struct op *t ));
_PROTOTYPE(int doexport, (struct op *t ));
_PROTOTYPE(int doreadonly, (struct op *t ));
_PROTOTYPE(static void rdexp, (char **wp, void (*f)(), int key));
_PROTOTYPE(static void badid, (char *s ));
_PROTOTYPE(int doset, (struct op *t ));
_PROTOTYPE(void varput, (char *s, int out ));
_PROTOTYPE(int dotimes, (void));
int
execute(t, pin, pout, act)
register struct op *t;
int *pin, *pout;
int act;
{
register struct op *t1;
int i, pv[2], rv, child, a;
char *cp, **wp, **wp2;
struct var *vp;
struct brkcon bc;
if (t == NULL)
return(0);
rv = 0;
a = areanum++;
wp = (wp2 = t->words) != NULL
? eval(wp2, t->type == TCOM ? DOALL : DOALL & ~DOKEY)
: NULL;
switch(t->type) {
case TPAREN:
case TCOM:
rv = forkexec(t, pin, pout, act, wp, &child);
if (child) {
exstat = rv;
leave();
}
break;
case TPIPE:
if ((rv = openpipe(pv)) < 0)
break;
pv[0] = remap(pv[0]);
pv[1] = remap(pv[1]);
(void) execute(t->left, pin, pv, 0);
rv = execute(t->right, pv, pout, 0);
break;
case TLIST:
(void) execute(t->left, pin, pout, 0);
rv = execute(t->right, pin, pout, 0);
break;
case TASYNC:
i = parent();
if (i != 0) {
if (i != -1) {
setval(lookup("!"), putn(i));
if (pin != NULL)
closepipe(pin);
if (talking) {
prs(putn(i));
prs("\n");
}
} else
rv = -1;
setstatus(rv);
} else {
signal(SIGINT, SIG_IGN);
signal(SIGQUIT, SIG_IGN);
if (talking)
signal(SIGTERM, SIG_DFL);
talking = 0;
if (pin == NULL) {
close(0);
open("/dev/null", 0);
}
exit(execute(t->left, pin, pout, FEXEC));
}
break;
case TOR:
case TAND:
rv = execute(t->left, pin, pout, 0);
if ((t1 = t->right)!=NULL && (rv == 0) == (t->type == TAND))
rv = execute(t1, pin, pout, 0);
break;
case TFOR:
if (wp == NULL) {
wp = dolv+1;
if ((i = dolc) < 0)
i = 0;
} else {
i = -1;
while (*wp++ != NULL)
;
}
vp = lookup(t->str);
while (setjmp(bc.brkpt))
if (isbreak)
goto broken;
brkset(&bc);
for (t1 = t->left; i-- && *wp != NULL;) {
setval(vp, *wp++);
rv = execute(t1, pin, pout, 0);
}
brklist = brklist->nextlev;
break;
case TWHILE:
case TUNTIL:
while (setjmp(bc.brkpt))
if (isbreak)
goto broken;
brkset(&bc);
t1 = t->left;
while ((execute(t1, pin, pout, 0) == 0) == (t->type == TWHILE))
rv = execute(t->right, pin, pout, 0);
brklist = brklist->nextlev;
break;
case TIF:
case TELIF:
if (t->right != NULL) {
rv = !execute(t->left, pin, pout, 0) ?
execute(t->right->left, pin, pout, 0):
execute(t->right->right, pin, pout, 0);
}
break;
case TCASE:
if ((cp = evalstr(t->str, DOSUB|DOTRIM)) == 0)
cp = "";
if ((t1 = findcase(t->left, cp)) != NULL)
rv = execute(t1, pin, pout, 0);
break;
case TBRACE:
/*
if (iopp = t->ioact)
while (*iopp)
if (iosetup(*iopp++, pin!=NULL, pout!=NULL)) {
rv = -1;
break;
}
*/
if (rv >= 0 && (t1 = t->left))
rv = execute(t1, pin, pout, 0);
break;
}
broken:
t->words = wp2;
isbreak = 0;
freehere(areanum);
freearea(areanum);
areanum = a;
if (talking && intr) {
closeall();
fail();
}
if ((i = trapset) != 0) {
trapset = 0;
runtrap(i);
}
return(rv);
}
static int
forkexec(t, pin, pout, act, wp, pforked)
register struct op *t;
int *pin, *pout;
int act;
char **wp;
int *pforked;
{
int i, rv, (*shcom)();
register int f;
char *cp;
struct ioword **iopp;
int resetsig;
char **owp;
owp = wp;
resetsig = 0;
*pforked = 0;
shcom = NULL;
rv = -1; /* system-detected error */
if (t->type == TCOM) {
while ((cp = *wp++) != NULL)
;
cp = *wp;
/* strip all initial assignments */
/* not correct wrt PATH=yyy command etc */
if (flag['x'])
echo (cp ? wp: owp);
if (cp == NULL && t->ioact == NULL) {
while ((cp = *owp++) != NULL && assign(cp, COPYV))
;
return(setstatus(0));
}
else if (cp != NULL)
shcom = inbuilt(cp);
}
t->words = wp;
f = act;
if (shcom == NULL && (f & FEXEC) == 0) {
i = parent();
if (i != 0) {
if (i == -1)
return(rv);
if (pin != NULL)
closepipe(pin);
return(pout==NULL? setstatus(waitfor(i,0)): 0);
}
if (talking) {
signal(SIGINT, SIG_IGN);
signal(SIGQUIT, SIG_IGN);
resetsig = 1;
}
talking = 0;
intr = 0;
(*pforked)++;
brklist = 0;
execflg = 0;
}
if (owp != NULL)
while ((cp = *owp++) != NULL && assign(cp, COPYV))
if (shcom == NULL)
export(lookup(cp));
#ifdef COMPIPE
if ((pin != NULL || pout != NULL) && shcom != NULL && shcom != doexec) {
err("piping to/from shell builtins not yet done");
return(-1);
}
#endif
if (pin != NULL) {
dup2(pin[0], 0);
closepipe(pin);
}
if (pout != NULL) {
dup2(pout[1], 1);
closepipe(pout);
}
if ((iopp = t->ioact) != NULL) {
if (shcom != NULL && shcom != doexec) {
prs(cp);
err(": cannot redirect shell command");
return(-1);
}
while (*iopp)
if (iosetup(*iopp++, pin!=NULL, pout!=NULL))
return(rv);
}
if (shcom)
return(setstatus((*shcom)(t)));
/* should use FIOCEXCL */
for (i=FDBASE; i<NOFILE; i++)
close(i);
if (resetsig) {
signal(SIGINT, SIG_DFL);
signal(SIGQUIT, SIG_DFL);
}
if (t->type == TPAREN)
exit(execute(t->left, NOPIPE, NOPIPE, FEXEC));
if (wp[0] == NULL)
exit(0);
cp = rexecve(wp[0], wp, makenv());
prs(wp[0]); prs(": "); warn(cp);
if (!execflg)
trap[0] = NULL;
leave();
/* NOTREACHED */
}
/*
* common actions when creating a new child
*/
static int
parent()
{
register int i;
i = fork();
if (i != 0) {
if (i == -1)
warn("try again");
}
return(i);
}
/*
* 0< 1> are ignored as required
* within pipelines.
*/
int
iosetup(iop, pipein, pipeout)
register struct ioword *iop;
int pipein, pipeout;
{
register u;
char *cp, *msg;
if (iop->io_unit == IODEFAULT) /* take default */
iop->io_unit = iop->io_flag&(IOREAD|IOHERE)? 0: 1;
if (pipein && iop->io_unit == 0)
return(0);
if (pipeout && iop->io_unit == 1)
return(0);
msg = iop->io_flag&(IOREAD|IOHERE)? "open": "create";
if ((iop->io_flag & IOHERE) == 0) {
cp = iop->io_name;
if ((cp = evalstr(cp, DOSUB|DOTRIM)) == NULL)
return(1);
}
if (iop->io_flag & IODUP) {
if (cp[1] || (!digit(*cp) && *cp != '-')) {
prs(cp);
err(": illegal >& argument");
return(1);
}
if (*cp == '-')
iop->io_flag = IOCLOSE;
iop->io_flag &= ~(IOREAD|IOWRITE);
}
switch (iop->io_flag) {
case IOREAD:
u = open(cp, 0);
break;
case IOHERE:
case IOHERE|IOXHERE:
u = herein(iop->io_name, iop->io_flag&IOXHERE);
cp = "here file";
break;
case IOWRITE|IOCAT:
if ((u = open(cp, 1)) >= 0) {
lseek(u, (long)0, 2);
break;
}
case IOWRITE:
u = creat(cp, 0666);
break;
case IODUP:
u = dup2(*cp-'0', iop->io_unit);
break;
case IOCLOSE:
close(iop->io_unit);
return(0);
}
if (u < 0) {
prs(cp);
prs(": cannot ");
warn(msg);
return(1);
} else {
if (u != iop->io_unit) {
dup2(u, iop->io_unit);
close(u);
}
}
return(0);
}
static void
echo(wp)
register char **wp;
{
register i;
prs("+");
for (i=0; wp[i]; i++) {
if (i)
prs(" ");
prs(wp[i]);
}
prs("\n");
}
static struct op **
find1case(t, w)
struct op *t;
char *w;
{
register struct op *t1;
struct op **tp;
register char **wp, *cp;
if (t == NULL)
return((struct op **)NULL);
if (t->type == TLIST) {
if ((tp = find1case(t->left, w)) != NULL)
return(tp);
t1 = t->right; /* TPAT */
} else
t1 = t;
for (wp = t1->words; *wp;)
if ((cp = evalstr(*wp++, DOSUB)) && gmatch(w, cp))
return(&t1->left);
return((struct op **)NULL);
}
static struct op *
findcase(t, w)
struct op *t;
char *w;
{
register struct op **tp;
return((tp = find1case(t, w)) != NULL? *tp: (struct op *)NULL);
}
/*
* Enter a new loop level (marked for break/continue).
*/
static void
brkset(bc)
struct brkcon *bc;
{
bc->nextlev = brklist;
brklist = bc;
}
/*
* Wait for the last process created.
* Print a message for each process found
* that was killed by a signal.
* Ignore interrupt signals while waiting
* unless `canintr' is true.
*/
int
waitfor(lastpid, canintr)
register int lastpid;
int canintr;
{
register int pid, rv;
int s;
int oheedint = heedint;
heedint = 0;
rv = 0;
do {
pid = wait(&s);
if (pid == -1) {
if (errno != EINTR || canintr)
break;
} else {
if ((rv = WAITSIG(s)) != 0) {
if (rv < NSIGNAL) {
if (signame[rv] != NULL) {
if (pid != lastpid) {
prn(pid);
prs(": ");
}
prs(signame[rv]);
}
} else {
if (pid != lastpid) {
prn(pid);
prs(": ");
}
prs("Signal "); prn(rv); prs(" ");
}
if (WAITCORE(s))
prs(" - core dumped");
if (rv >= NSIGNAL || signame[rv])
prs("\n");
rv = -1;
} else
rv = WAITVAL(s);
}
} while (pid != lastpid);
heedint = oheedint;
if (intr)
if (talking) {
if (canintr)
intr = 0;
} else {
if (exstat == 0) exstat = rv;
onintr(0);
}
return(rv);
}
int
setstatus(s)
register int s;
{
exstat = s;
setval(lookup("?"), putn(s));
return(s);
}
/*
* PATH-searching interface to execve.
* If getenv("PATH") were kept up-to-date,
* execvp might be used.
*/
char *
rexecve(c, v, envp)
char *c, **v, **envp;
{
register int i;
register char *sp, *tp;
int eacces = 0, asis = 0;
sp = any('/', c)? "": path->value;
asis = *sp == '\0';
while (asis || *sp != '\0') {
asis = 0;
tp = e.linep;
for (; *sp != '\0'; tp++)
if ((*tp = *sp++) == ':') {
asis = *sp == '\0';
break;
}
if (tp != e.linep)
*tp++ = '/';
for (i = 0; (*tp++ = c[i++]) != '\0';)
;
execve(e.linep, v, envp);
switch (errno) {
case ENOEXEC:
*v = e.linep;
tp = *--v;
*v = e.linep;
execve("/bin/sh", v, envp);
*v = tp;
return("no Shell");
case ENOMEM:
return("program too big");
case E2BIG:
return("argument list too long");
case EACCES:
eacces++;
break;
}
}
return(errno==ENOENT ? "not found" : "cannot execute");
}
/*
* Run the command produced by generator `f'
* applied to stream `arg'.
*/
int
run(argp, f)
struct ioarg *argp;
int (*f)();
{
struct op *otree;
struct wdblock *swdlist;
struct wdblock *siolist;
jmp_buf ev, rt;
xint *ofail;
int rv;
areanum++;
swdlist = wdlist;
siolist = iolist;
otree = outtree;
ofail = failpt;
rv = -1;
if (newenv(setjmp(errpt = ev)) == 0) {
wdlist = 0;
iolist = 0;
pushio(argp, f);
e.iobase = e.iop;
yynerrs = 0;
if (setjmp(failpt = rt) == 0 && yyparse() == 0)
rv = execute(outtree, NOPIPE, NOPIPE, 0);
quitenv();
}
wdlist = swdlist;
iolist = siolist;
failpt = ofail;
outtree = otree;
freearea(areanum--);
return(rv);
}
/* -------- do.c -------- */
/* #include "sh.h" */
/*
* built-in commands: doX
*/
int
dolabel()
{
return(0);
}
int
dochdir(t)
register struct op *t;
{
register char *cp, *er;
if ((cp = t->words[1]) == NULL && (cp = homedir->value) == NULL)
er = ": no home directory";
else if(chdir(cp) < 0)
er = ": bad directory";
else
return(0);
prs(cp != NULL? cp: "cd");
err(er);
return(1);
}
int
doshift(t)
register struct op *t;
{
register n;
n = t->words[1]? getn(t->words[1]): 1;
if(dolc < n) {
err("nothing to shift");
return(1);
}
dolv[n] = dolv[0];
dolv += n;
dolc -= n;
setval(lookup("#"), putn(dolc));
return(0);
}
/*
* execute login and newgrp directly
*/
int
dologin(t)
struct op *t;
{
register char *cp;
if (talking) {
signal(SIGINT, SIG_DFL);
signal(SIGQUIT, SIG_DFL);
}
cp = rexecve(t->words[0], t->words, makenv());
prs(t->words[0]); prs(": "); err(cp);
return(1);
}
int
doumask(t)
register struct op *t;
{
register int i, n;
register char *cp;
if ((cp = t->words[1]) == NULL) {
i = umask(0);
umask(i);
for (n=3*4; (n-=3) >= 0;)
putc('0'+((i>>n)&07));
putc('\n');
} else {
for (n=0; *cp>='0' && *cp<='9'; cp++)
n = n*8 + (*cp-'0');
umask(n);
}
return(0);
}
int
doexec(t)
register struct op *t;
{
register i;
jmp_buf ex;
xint *ofail;
t->ioact = NULL;
for(i = 0; (t->words[i]=t->words[i+1]) != NULL; i++)
;
if (i == 0)
return(1);
execflg = 1;
ofail = failpt;
if (setjmp(failpt = ex) == 0)
execute(t, NOPIPE, NOPIPE, FEXEC);
failpt = ofail;
execflg = 0;
return(1);
}
int
dodot(t)
struct op *t;
{
register i;
register char *sp, *tp;
char *cp;
if ((cp = t->words[1]) == NULL)
return(0);
sp = any('/', cp)? ":": path->value;
while (*sp) {
tp = e.linep;
while (*sp && (*tp = *sp++) != ':')
tp++;
if (tp != e.linep)
*tp++ = '/';
for (i = 0; (*tp++ = cp[i++]) != '\0';)
;
if ((i = open(e.linep, 0)) >= 0) {
exstat = 0;
next(remap(i));
return(exstat);
}
}
prs(cp);
err(": not found");
return(-1);
}
int
dowait(t)
struct op *t;
{
register i;
register char *cp;
if ((cp = t->words[1]) != NULL) {
i = getn(cp);
if (i == 0)
return(0);
} else
i = -1;
setstatus(waitfor(i, 1));
return(0);
}
int
doread(t)
struct op *t;
{
register char *cp, **wp;
register nb;
register int nl = 0;
if (t->words[1] == NULL) {
err("usage: read name ...");
return(1);
}
for (wp = t->words+1; *wp; wp++) {
for (cp = e.linep; !nl && cp < elinep-1; cp++)
if ((nb = read(0, cp, sizeof(*cp))) != sizeof(*cp) ||
(nl = (*cp == '\n')) ||
(wp[1] && any(*cp, ifs->value)))
break;
*cp = 0;
if (nb <= 0)
break;
setval(lookup(*wp), e.linep);
}
return(nb <= 0);
}
int
doeval(t)
register struct op *t;
{
return(RUN(awordlist, t->words+1, wdchar));
}
int
dotrap(t)
register struct op *t;
{
register int n, i;
register int resetsig;
if (t->words[1] == NULL) {
for (i=0; i<=_NSIG; i++)
if (trap[i]) {
prn(i);
prs(": ");
prs(trap[i]);
prs("\n");
}
return(0);
}
resetsig = digit(*t->words[1]);
for (i = resetsig ? 1 : 2; t->words[i] != NULL; ++i) {
n = getsig(t->words[i]);
xfree(trap[n]);
trap[n] = 0;
if (!resetsig) {
if (*t->words[1] != '\0') {
trap[n] = strsave(t->words[1], 0);
setsig(n, sig);
} else
setsig(n, SIG_IGN);
} else {
if (talking)
if (n == SIGINT)
setsig(n, onintr);
else
setsig(n, n == SIGQUIT ? SIG_IGN
: SIG_DFL);
else
setsig(n, SIG_DFL);
}
}
return(0);
}
int
getsig(s)
char *s;
{
register int n;
if ((n = getn(s)) < 0 || n > _NSIG) {
err("trap: bad signal number");
n = 0;
}
return(n);
}
void
setsig(n, f)
register n;
_PROTOTYPE(void (*f), (int));
{
if (n == 0)
return;
if (signal(n, SIG_IGN) != SIG_IGN || ourtrap[n]) {
ourtrap[n] = 1;
signal(n, f);
}
}
int
getn(as)
char *as;
{
register char *s;
register n, m;
s = as;
m = 1;
if (*s == '-') {
m = -1;
s++;
}
for (n = 0; digit(*s); s++)
n = (n*10) + (*s-'0');
if (*s) {
prs(as);
err(": bad number");
}
return(n*m);
}
int
dobreak(t)
struct op *t;
{
return(brkcontin(t->words[1], 1));
}
int
docontinue(t)
struct op *t;
{
return(brkcontin(t->words[1], 0));
}
static int
brkcontin(cp, val)
register char *cp;
int val;
{
register struct brkcon *bc;
register nl;
nl = cp == NULL? 1: getn(cp);
if (nl <= 0)
nl = 999;
do {
if ((bc = brklist) == NULL)
break;
brklist = bc->nextlev;
} while (--nl);
if (nl) {
err("bad break/continue level");
return(1);
}
isbreak = val;
longjmp(bc->brkpt, 1);
/* NOTREACHED */
}
int
doexit(t)
struct op *t;
{
register char *cp;
execflg = 0;
if ((cp = t->words[1]) != NULL)
setstatus(getn(cp));
leave();
/* NOTREACHED */
}
int
doexport(t)
struct op *t;
{
rdexp(t->words+1, export, EXPORT);
return(0);
}
int
doreadonly(t)
struct op *t;
{
rdexp(t->words+1, ronly, RONLY);
return(0);
}
static void
rdexp(wp, f, key)
register char **wp;
void (*f)();
int key;
{
if (*wp != NULL) {
for (; *wp != NULL; wp++)
if (checkname(*wp))
(*f)(lookup(*wp));
else
badid(*wp);
} else
putvlist(key, 1);
}
static void
badid(s)
register char *s;
{
prs(s);
err(": bad identifier");
}
int
doset(t)
register struct op *t;
{
register struct var *vp;
register char *cp;
register n;
if ((cp = t->words[1]) == NULL) {
for (vp = vlist; vp; vp = vp->next)
varput(vp->name, 1);
return(0);
}
if (*cp == '-') {
/* bad: t->words++; */
for(n = 0; (t->words[n]=t->words[n+1]) != NULL; n++)
;
if (*++cp == 0)
flag['x'] = flag['v'] = 0;
else
for (; *cp; cp++)
switch (*cp) {
case 'e':
if (!talking)
flag['e']++;
break;
default:
if (*cp>='a' && *cp<='z')
flag[*cp]++;
break;
}
setdash();
}
if (t->words[1]) {
t->words[0] = dolv[0];
for (n=1; t->words[n]; n++)
setarea((char *)t->words[n], 0);
dolc = n-1;
dolv = t->words;
setval(lookup("#"), putn(dolc));
setarea((char *)(dolv-1), 0);
}
return(0);
}
void
varput(s, out)
register char *s;
int out;
{
if (letnum(*s)) {
write(out, s, strlen(s));
write(out, "\n", 1);
}
}
#define SECS 60L
#define MINS 3600L
int
dotimes()
{
struct tms tbuf;
times(&tbuf);
prn((int)(tbuf.tms_cutime / MINS));
prs("m");
prn((int)((tbuf.tms_cutime % MINS) / SECS));
prs("s ");
prn((int)(tbuf.tms_cstime / MINS));
prs("m");
prn((int)((tbuf.tms_cstime % MINS) / SECS));
prs("s\n");
return(0);
}
struct builtin {
char *command;
int (*fn)();
};
static struct builtin builtin[] = {
":", dolabel,
"cd", dochdir,
"shift", doshift,
"exec", doexec,
"wait", dowait,
"read", doread,
"eval", doeval,
"trap", dotrap,
"break", dobreak,
"continue", docontinue,
"exit", doexit,
"export", doexport,
"readonly", doreadonly,
"set", doset,
".", dodot,
"umask", doumask,
"login", dologin,
"newgrp", dologin,
"times", dotimes,
0,
};
int (*inbuilt(s))()
register char *s;
{
register struct builtin *bp;
for (bp = builtin; bp->command != NULL; bp++)
if (strcmp(bp->command, s) == 0)
return(bp->fn);
return((int(*)())NULL);
}