sh3.c

操作系统源代码

	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);
}