[unix-history] / usr / src / sys / kern / kern_proc.c

/*	kern_proc.c	4.9	%G%	*/

#include "../h/param.h"
#include "../h/systm.h"
#include "../h/map.h"
#include "../h/mtpr.h"
#include "../h/dir.h"
#include "../h/user.h"
#include "../h/proc.h"
#include "../h/buf.h"
#include "../h/reg.h"
#include "../h/inode.h"
#include "../h/seg.h"
#include "../h/acct.h"
#include "/usr/include/wait.h"
#include "../h/pte.h"
#include "../h/vm.h"
#include "../h/text.h"
#include "../h/psl.h"
#include "../h/vlimit.h"
#include "../h/file.h"

/*
 * exec system call, with and without environments.
 */
struct execa {
	char	*fname;
	char	**argp;
	char	**envp;
};

exec()
{
	((struct execa *)u.u_ap)->envp = NULL;
	exece();
}

exece()
{
	register nc;
	register char *cp;
	register struct buf *bp;
	register struct execa *uap;
	int na, ne, ucp, ap, c;
	int indir, uid, gid;
	char *sharg;
	struct inode *ip;
	swblk_t bno;
	char cfname[DIRSIZ];
	char cfarg[SHSIZE];

	if ((ip = namei(uchar, 0)) == NULL)
		return;

	bno = 0;
	bp = 0;
	indir = 0;
	uid = u.u_uid;
	gid = u.u_gid;

	if (ip->i_mode & ISUID)
		uid = ip->i_uid;
	if (ip->i_mode & ISGID)
		gid = ip->i_gid;

  again:
	if(access(ip, IEXEC))
		goto bad;
	if((u.u_procp->p_flag&STRC) && access(ip, IREAD))
		goto bad;
	if((ip->i_mode & IFMT) != IFREG ||
	   (ip->i_mode & (IEXEC|(IEXEC>>3)|(IEXEC>>6))) == 0) {
		u.u_error = EACCES;
		goto bad;
	}

	/*
	 * Read in first few bytes of file for segment sizes, ux_mag:
	 *	407 = plain executable
	 *	410 = RO text
	 *	413 = demand paged RO text
	 * Also an ASCII line beginning with #! is
	 * the file name of a ``shell'' and arguments may be prepended
	 * to the argument list if given here.
	 *
	 * SHELL NAMES ARE LIMITED IN LENGTH.
	 *
	 * ONLY ONE ARGUMENT MAY BE PASSED TO THE SHELL FROM
	 * THE ASCII LINE.
	 */
	u.u_base = (caddr_t)&u.u_exdata;
	u.u_count = sizeof(u.u_exdata);
	u.u_offset = 0;
	u.u_segflg = 1;
	readi(ip);
	u.u_segflg = 0;
	if(u.u_error)
		goto bad;
	if (u.u_count > sizeof(u.u_exdata) - sizeof(u.u_exdata.Ux_A)
		&& u.u_exdata.ux_shell[0] != '#') {
		u.u_error = ENOEXEC;
		goto bad;
	}
	switch (u.u_exdata.ux_mag) {

	case 0407:
		u.u_exdata.ux_dsize += u.u_exdata.ux_tsize;
		u.u_exdata.ux_tsize = 0;
		break;

	case 0413:
	case 0410:
		if (u.u_exdata.ux_tsize == 0) {
			u.u_error = ENOEXEC;
			goto bad;
		}
		break;

	default:
		if (u.u_exdata.ux_shell[0] != '#' ||
		    u.u_exdata.ux_shell[1] != '!' ||
		    indir) {
			u.u_error = ENOEXEC;
			goto bad;
		}
		cp = &u.u_exdata.ux_shell[2];		/* skip "#!" */
		while (cp < &u.u_exdata.ux_shell[SHSIZE]) {
			if (*cp == '\t')
				*cp = ' ';
			else if (*cp == '\n') {
				*cp = '\0';
				break;
			}
			cp++;
		}
		if (*cp != '\0') {
			u.u_error = ENOEXEC;
			goto bad;
		}
		cp = &u.u_exdata.ux_shell[2];
		while (*cp == ' ')
			cp++;
		u.u_dirp = cp;
		while (*cp && *cp != ' ')
			cp++;
		sharg = NULL;
		if (*cp) {
			*cp++ = '\0';
			while (*cp == ' ')
				cp++;
			if (*cp) {
				bcopy((caddr_t)cp, (caddr_t)cfarg, SHSIZE);
				sharg = cfarg;
			}
		}
		bcopy((caddr_t)u.u_dbuf, (caddr_t)cfname, DIRSIZ);
		indir = 1;
		iput(ip);
		ip = namei(schar, 0);
		if (ip == NULL)
			return;
		goto again;
	}

	/*
	 * Collect arguments on "file" in swap space.
	 */
	na = 0;
	ne = 0;
	nc = 0;
	uap = (struct execa *)u.u_ap;
	if ((bno = rmalloc(argmap, ctod(clrnd((int) btoc(NCARGS))))) == 0) {
		swkill(u.u_procp, "exece");
		goto bad;
	}
	if (bno % CLSIZE)
		panic("execa rmalloc");
	if (uap->argp) for (;;) {
		ap = NULL;
		if (na == 1 && indir) {
			if (sharg == NULL)
				ap = (int)uap->fname;
		} else if (na == 2 && indir && sharg != NULL)
			ap = (int)uap->fname;
		else if (uap->argp) {
			ap = fuword((caddr_t)uap->argp);
			uap->argp++;
		}
		if (ap==NULL && uap->envp) {
			uap->argp = NULL;
			if ((ap = fuword((caddr_t)uap->envp)) == NULL)
				break;
			uap->envp++;
			ne++;
		}
		if (ap==NULL)
			break;
		na++;
		if(ap == -1)
			u.u_error = EFAULT;
		do {
			if (nc >= NCARGS-1)
				u.u_error = E2BIG;
			if (indir && na == 2 && sharg != NULL)
				c = *sharg++ & 0377;
			else if ((c = fubyte((caddr_t)ap++)) < 0)
				u.u_error = EFAULT;
			if (u.u_error) {
				if (bp)
					brelse(bp);
				bp = 0;
				goto badarg;
			}
			if ((nc&BMASK) == 0) {
				if (bp)
					bdwrite(bp);
				bp = getblk(argdev,
				    (daddr_t)(dbtofsb(bno)+(nc>>BSHIFT)));
				cp = bp->b_un.b_addr;
			}
			nc++;
			*cp++ = c;
		} while (c>0);
	}
	if (bp)
		bdwrite(bp);
	bp = 0;
	nc = (nc + NBPW-1) & ~(NBPW-1);
	if (indir)
		bcopy((caddr_t)cfname, (caddr_t)u.u_dbuf, DIRSIZ);
	getxfile(ip, nc + (na+4)*NBPW, uid, gid);
	if (u.u_error) {
badarg:
		for (c = 0; c < nc; c += BSIZE)
			if (bp = baddr(argdev, dbtofsb(bno)+(c>>BSHIFT))) {
				bp->b_flags |= B_AGE;		/* throw away */
				bp->b_flags &= ~B_DELWRI;	/* cancel io */
				brelse(bp);
				bp = 0;
			}
		goto bad;
	}

	/*
	 * copy back arglist
	 */

	ucp = USRSTACK - nc - NBPW;
	ap = ucp - na*NBPW - 3*NBPW;
	u.u_ar0[SP] = ap;
	(void) suword((caddr_t)ap, na-ne);
	nc = 0;
	for (;;) {
		ap += NBPW;
		if (na==ne) {
			(void) suword((caddr_t)ap, 0);
			ap += NBPW;
		}
		if (--na < 0)
			break;
		(void) suword((caddr_t)ap, ucp);
		do {
			if ((nc&BMASK) == 0) {
				if (bp)
					brelse(bp);
				bp = bread(argdev,
				    (daddr_t)(dbtofsb(bno)+(nc>>BSHIFT)));
				bp->b_flags |= B_AGE;		/* throw away */
				bp->b_flags &= ~B_DELWRI;	/* cancel io */
				cp = bp->b_un.b_addr;
			}
			(void) subyte((caddr_t)ucp++, (c = *cp++));
			nc++;
		} while(c&0377);
	}
	(void) suword((caddr_t)ap, 0);
	(void) suword((caddr_t)ucp, 0);
	setregs();
bad:
	if (bp)
		brelse(bp);
	if (bno)
		rmfree(argmap, ctod(clrnd((int) btoc(NCARGS))), bno);
	iput(ip);
}

/*
 * Read in and set up memory for executed file.
 */
getxfile(ip, nargc, uid, gid)
register struct inode *ip;
{
	register size_t ts, ds, ss;
	int pagi;

	if (u.u_exdata.ux_mag == 0413)
		pagi = SPAGI;
	else
		pagi = 0;

	if(u.u_exdata.ux_tsize!=0 && (ip->i_flag&ITEXT)==0 && ip->i_count!=1) {
		register struct file *fp;

		for (fp = file; fp < fileNFILE; fp++)
			if (fp->f_inode == ip && (fp->f_flag&FWRITE)) {
				u.u_error = ETXTBSY;
				goto bad;
			}
	}

	/*
	 * find text and data sizes
	 * try them out for possible
	 * exceed of max sizes
	 */

	ts = clrnd(btoc(u.u_exdata.ux_tsize));
	ds = clrnd(btoc((u.u_exdata.ux_dsize+u.u_exdata.ux_bsize)));
	ss = clrnd(SSIZE + btoc(nargc));
	if (chksize(ts, ds, ss))
		goto bad;
	u.u_cdmap = zdmap;
	u.u_csmap = zdmap;
	if (swpexpand(ds, ss, &u.u_cdmap, &u.u_csmap) == NULL)
		goto bad;

	/*
	 * At this point, committed to the new image!
	 * Release virtual memory resources of old process, and
	 * initialize the virtual memory of the new process.
	 * If we resulted from vfork(), instead wakeup our
	 * parent who will set SVFDONE when he has taken back
	 * our resources.
	 */
	u.u_prof.pr_scale = 0;
	if ((u.u_procp->p_flag & SVFORK) == 0)
		vrelvm();
	else {
		u.u_procp->p_flag &= ~SVFORK;
		u.u_procp->p_flag |= SKEEP;
		wakeup((caddr_t)u.u_procp);
		while ((u.u_procp->p_flag & SVFDONE) == 0)
			sleep((caddr_t)u.u_procp, PZERO - 1);
		u.u_procp->p_flag &= ~(SVFDONE|SKEEP);
	}
	u.u_procp->p_flag &= ~(SPAGI|SANOM|SUANOM|SNUSIG);
	u.u_procp->p_flag |= pagi;
	u.u_dmap = u.u_cdmap;
	u.u_smap = u.u_csmap;
	vgetvm(ts, ds, ss);

	if (pagi == 0) {
		/*
		 * Read in data segment.
		 */
		u.u_base = (char *)ctob(ts);
		u.u_offset = sizeof(u.u_exdata)+u.u_exdata.ux_tsize;
		u.u_count = u.u_exdata.ux_dsize;
		readi(ip);
	}
	xalloc(ip, pagi);
	if (pagi && u.u_procp->p_textp)
		vinifod((struct fpte *)dptopte(u.u_procp, 0),
		    PG_FTEXT, u.u_procp->p_textp->x_iptr,
		    1 + ts/CLSIZE, (int)btoc(u.u_exdata.ux_dsize));

	/* THIS SHOULD BE DONE AT A LOWER LEVEL, IF AT ALL */
	mtpr(TBIA, 0);

	/*
	 * set SUID/SGID protections, if no tracing
	 */
	if ((u.u_procp->p_flag&STRC)==0) {
#ifndef	MELB
		if(u.u_uid != 0)
#endif
		{
			u.u_uid = uid;
			u.u_procp->p_uid = uid;
		}
		u.u_gid = gid;
	} else
		psignal(u.u_procp, SIGTRAP);
	u.u_tsize = ts;
	u.u_dsize = ds;
	u.u_ssize = ss;
bad:
	return;
}

/*
 * Clear registers on exec
 */
setregs()
{
	register int (**rp)();
	register i;
	long sigmask;

	for(rp = &u.u_signal[0], sigmask = 1L; rp < &u.u_signal[NSIG];
	    sigmask <<= 1, rp++) {
		switch (*rp) {

		case SIG_IGN:
		case SIG_DFL:
		case SIG_HOLD:
			continue;

		default:
			/*
			 * Normal or deferring catch; revert to default.
			 */
			(void) spl6();
			*rp = SIG_DFL;
			if ((int)*rp & 1)
				u.u_procp->p_siga0 |= sigmask;
			else
				u.u_procp->p_siga1 &= ~sigmask;
			if ((int)*rp & 2)
				u.u_procp->p_siga1 |= sigmask;
			else
				u.u_procp->p_siga1 &= ~sigmask;
			(void) spl0();
			continue;
		}
	}
/*
	for(rp = &u.u_ar0[0]; rp < &u.u_ar0[16];)
		*rp++ = 0;
*/
	u.u_ar0[PC] = u.u_exdata.ux_entloc + 2; /* skip over entry mask */
	for(i=0; i<NOFILE; i++) {
		if (u.u_pofile[i]&EXCLOSE) {
			closef(u.u_ofile[i]);
			u.u_ofile[i] = NULL;
			u.u_pofile[i] &= ~EXCLOSE;
		}
	}
	/*
	 * Remember file name for accounting.
	 */
	u.u_acflag &= ~AFORK;
	bcopy((caddr_t)u.u_dbuf, (caddr_t)u.u_comm, DIRSIZ);
}

/*
 * exit system call:
 * pass back caller's arg
 */
rexit()
{
	register struct a {
		int	rval;
	} *uap;

	uap = (struct a *)u.u_ap;
	exit((uap->rval & 0377) << 8);
}

/*
 * Release resources.
 * Save u. area for parent to look at.
 * Enter zombie state.
 * Wake up parent and init processes,
 * and dispose of children.
 */
exit(rv)
{
	register int i;
	register struct proc *p, *q;
	register struct file *f;
	register int x;

#ifdef PGINPROF
	vmsizmon();
#endif
	p = u.u_procp;
	p->p_flag &= ~(STRC|SULOCK);
	p->p_flag |= SWEXIT;
	p->p_clktim = 0;
	(void) spl6();
	if ((int)SIG_IGN & 1)
		p->p_siga0 = ~0;
	else
		p->p_siga0 = 0;
	if ((int)SIG_IGN & 2)
		p->p_siga1 = ~0;
	else
		p->p_siga1 = 0;
	(void) spl0();
	p->p_cpticks = 0;
	p->p_pctcpu = 0;
	for(i=0; i<NSIG; i++)
		u.u_signal[i] = SIG_IGN;
	/*
	 * Release virtual memory.  If we resulted from
	 * a vfork(), instead give the resources back to
	 * the parent.
	 */
	if ((p->p_flag & SVFORK) == 0)
		vrelvm();
	else {
		p->p_flag &= ~SVFORK;
		wakeup((caddr_t)p);
		while ((p->p_flag & SVFDONE) == 0)
			sleep((caddr_t)p, PZERO - 1);
		p->p_flag &= ~SVFDONE;
	}
	for(i=0; i<NOFILE; i++) {
		f = u.u_ofile[i];
		u.u_ofile[i] = NULL;
		closef(f);
	}
	plock(u.u_cdir);
	iput(u.u_cdir);
	if (u.u_rdir) {
		plock(u.u_rdir);
		iput(u.u_rdir);
	}
	u.u_limit[LIM_FSIZE] = INFINITY;
	acct();
	vrelpt(u.u_procp);
	vrelu(u.u_procp, 0);
	multprog--;
/*	spl7();			/* clock will get mad because of overlaying */
	p->p_stat = SZOMB;
	noproc = 1;
	i = PIDHASH(p->p_pid);
	x = p - proc;
	if (pidhash[i] == x)
		pidhash[i] = p->p_idhash;
	else {
		for (i = pidhash[i]; i != 0; i = proc[i].p_idhash)
			if (proc[i].p_idhash == x) {
				proc[i].p_idhash = p->p_idhash;
				goto done;
			}
		panic("exit");
	}
	if (p->p_pid == 1)
		panic("init died");
done:
	((struct xproc *)p)->xp_xstat = rv;		/* overlay */
	((struct xproc *)p)->xp_vm = u.u_vm;		/* overlay */
	vmsadd(&((struct xproc *)p)->xp_vm, &u.u_cvm);
	for(q = proc; q < procNPROC; q++)
		if(q->p_pptr == p) {
			q->p_pptr = &proc[1];
			q->p_ppid = 1;
			wakeup((caddr_t)&proc[1]);
			/*
			 * Traced processes are killed
			 * since their existence means someone is screwing up.
			 * Stopped processes are sent a hangup and a continue.
			 * This is designed to be ``safe'' for setuid
			 * processes since they must be willing to tolerate
			 * hangups anyways.
			 */
			if (q->p_flag&STRC) {
				q->p_flag &= ~STRC;
				psignal(q, SIGKILL);
			} else if (q->p_stat == SSTOP) {
				psignal(q, SIGHUP);
				psignal(q, SIGCONT);
			}
			/*
			 * Protect this process from future
			 * tty signals, clear TSTP/TTIN/TTOU if pending,
			 * and set SDETACH bit on procs.
			 */
			(void) spgrp(q, -1);
		}
	wakeup((caddr_t)p->p_pptr);
	psignal(p->p_pptr, SIGCHLD);
	swtch();
}

wait()
{
	struct vtimes vm;
	struct vtimes *vp;

	if ((u.u_ar0[PS] & PSL_ALLCC) != PSL_ALLCC) {
		wait1(0, (struct vtimes *)0);
		return;
	}
	vp = (struct vtimes *)u.u_ar0[R1];
	wait1(u.u_ar0[R0], &vm);
	if (u.u_error)
		return;
	(void) copyout((caddr_t)&vm, (caddr_t)vp, sizeof (struct vtimes));
}

/*
 * Wait system call.
 * Search for a terminated (zombie) child,
 * finally lay it to rest, and collect its status.
 * Look also for stopped (traced) children,
 * and pass back status from them.
 */
wait1(options, vp)
	register options;
	struct vtimes *vp;
{
	register f;
	register struct proc *p;

	f = 0;
loop:
	for(p = proc; p < procNPROC; p++)
	if(p->p_pptr == u.u_procp) {
		f++;
		if(p->p_stat == SZOMB) {
			u.u_r.r_val1 = p->p_pid;
			u.u_r.r_val2 = ((struct xproc *)p)->xp_xstat;
			((struct xproc *)p)->xp_xstat = 0;
			if (vp)
				*vp = ((struct xproc *)p)->xp_vm;
			vmsadd(&u.u_cvm, &((struct xproc *)p)->xp_vm);
			((struct xproc *)p)->xp_vm = zvms;
			p->p_stat = NULL;
			p->p_pid = 0;
			p->p_ppid = 0;
			p->p_pptr = 0;
			p->p_sig = 0;
			p->p_siga0 = 0;
			p->p_siga1 = 0;
			p->p_pgrp = 0;
			p->p_flag = 0;
			p->p_wchan = 0;
			p->p_cursig = 0;
			return;
		}
		if (p->p_stat == SSTOP && (p->p_flag&SWTED)==0 &&
		    (p->p_flag&STRC || options&WUNTRACED)) {
			p->p_flag |= SWTED;
			u.u_r.r_val1 = p->p_pid;
			u.u_r.r_val2 = (p->p_cursig<<8) | WSTOPPED;
			return;
		}
	}
	if (f==0) {
		u.u_error = ECHILD;
		return;
	}
	if (options&WNOHANG) {
		u.u_r.r_val1 = 0;
		return;
	}
	if ((u.u_procp->p_flag&SNUSIG) && setjmp(u.u_qsav)) {
		u.u_eosys = RESTARTSYS;
		return;
	}
	sleep((caddr_t)u.u_procp, PWAIT);
	goto loop;
}

/*
 * fork system call.
 */
fork()
{

	u.u_cdmap = zdmap;
	u.u_csmap = zdmap;
	if (swpexpand(u.u_dsize, u.u_ssize, &u.u_cdmap, &u.u_csmap) == 0) {
		u.u_r.r_val2 = 0;
		return;
	}
	fork1(0);
}

fork1(isvfork)
{
	register struct proc *p1, *p2;
	register a;

	a = 0;
	p2 = NULL;
	for(p1 = proc; p1 < procNPROC; p1++) {
		if (p1->p_stat==NULL && p2==NULL)
			p2 = p1;
		else {
			if (p1->p_uid==u.u_uid && p1->p_stat!=NULL)
				a++;
		}
	}
	/*
	 * Disallow if
	 *  No processes at all;
	 *  not su and too many procs owned; or
	 *  not su and would take last slot.
	 */
	if (p2==NULL)
		tablefull("proc");
	if (p2==NULL || (u.u_uid!=0 && (p2==procNPROC-1 || a>MAXUPRC))) {
		u.u_error = EAGAIN;
		if (!isvfork) {
			(void) vsexpand(0, &u.u_cdmap, 1);
			(void) vsexpand(0, &u.u_csmap, 1);
		}
		goto out;
	}
	p1 = u.u_procp;
	if(newproc(isvfork)) {
		u.u_r.r_val1 = p1->p_pid;
		u.u_r.r_val2 = 1;  /* child */
		u.u_start = time;
		u.u_acflag = AFORK;
		return;
	}
	u.u_r.r_val1 = p2->p_pid;

out:
	u.u_r.r_val2 = 0;
}

/*
 * break system call.
 *  -- bad planning: "break" is a dirty word in C.
 */
sbreak()
{
	struct a {
		char	*nsiz;
	};
	register int n, d;

	/*
	 * set n to new data size
	 * set d to new-old
	 */

	n = btoc(((struct a *)u.u_ap)->nsiz);
	if (!u.u_sep)
		n -= ctos(u.u_tsize) * stoc(1);
	if (n < 0)
		n = 0;
	d = clrnd(n - u.u_dsize);
	if (ctob(u.u_dsize+d) > u.u_limit[LIM_DATA]) {
		u.u_error = ENOMEM;
		return;
	}
	if (chksize(u.u_tsize, u.u_dsize+d, u.u_ssize))
		return;
	if (swpexpand(u.u_dsize+d, u.u_ssize, &u.u_dmap, &u.u_smap)==0)
		return;
	expand(d, P0BR);
}
Commit	Line	Data
62901f34	1	/* kern_proc.c 4.9 %G% */
29dd101b BJ	2
	3	#include "../h/param.h"
	4	#include "../h/systm.h"
	5	#include "../h/map.h"
	6	#include "../h/mtpr.h"
	7	#include "../h/dir.h"
	8	#include "../h/user.h"
	9	#include "../h/proc.h"
	10	#include "../h/buf.h"
	11	#include "../h/reg.h"
	12	#include "../h/inode.h"
	13	#include "../h/seg.h"
	14	#include "../h/acct.h"
8643403f	15	#include "/usr/include/wait.h"
29dd101b BJ	16	#include "../h/pte.h"
	17	#include "../h/vm.h"
	18	#include "../h/text.h"
bdfe5b0f	19	#include "../h/psl.h"
b07c4d64	20	#include "../h/vlimit.h"
3ca1542b	21	#include "../h/file.h"
29dd101b BJ	22
	23	/*
	24	* exec system call, with and without environments.
	25	*/
	26	struct execa {
	27	char *fname;
	28	char **argp;
	29	char **envp;
	30	};
	31
	32	exec()
	33	{
	34	((struct execa *)u.u_ap)->envp = NULL;
	35	exece();
	36	}
	37
	38	exece()
	39	{
	40	register nc;
	41	register char *cp;
	42	register struct buf *bp;
	43	register struct execa *uap;
	44	int na, ne, ucp, ap, c;
7eeaac77 RE	45	int indir, uid, gid;
7eeaac77 RE	46	char *sharg;
29dd101b BJ	47	struct inode *ip;
29dd101b BJ	48	swblk_t bno;
7eeaac77 RE	49	char cfname[DIRSIZ];
7eeaac77 RE	50	char cfarg[SHSIZE];
29dd101b BJ	51
	52	if ((ip = namei(uchar, 0)) == NULL)
	53	return;
7eeaac77	54
29dd101b BJ	55	bno = 0;
29dd101b BJ	56	bp = 0;
7eeaac77 RE	57	indir = 0;
	58	uid = u.u_uid;
	59	gid = u.u_gid;
	60
	61	if (ip->i_mode & ISUID)
	62	uid = ip->i_uid;
	63	if (ip->i_mode & ISGID)
	64	gid = ip->i_gid;
	65
	66	again:
29dd101b BJ	67	if(access(ip, IEXEC))
29dd101b BJ	68	goto bad;
eb83bf86 BJ	69	if((u.u_procp->p_flag&STRC) && access(ip, IREAD))
eb83bf86 BJ	70	goto bad;
29dd101b BJ	71	if((ip->i_mode & IFMT) != IFREG \|\|
	72	(ip->i_mode & (IEXEC\|(IEXEC>>3)\|(IEXEC>>6))) == 0) {
	73	u.u_error = EACCES;
	74	goto bad;
	75	}
7eeaac77 RE	76
	77	/*
	78	* Read in first few bytes of file for segment sizes, ux_mag:
	79	* 407 = plain executable
	80	* 410 = RO text
	81	* 413 = demand paged RO text
	82	* Also an ASCII line beginning with #! is
	83	* the file name of a ``shell'' and arguments may be prepended
	84	* to the argument list if given here.
	85	*
	86	* SHELL NAMES ARE LIMITED IN LENGTH.
	87	*
	88	* ONLY ONE ARGUMENT MAY BE PASSED TO THE SHELL FROM
	89	* THE ASCII LINE.
	90	*/
	91	u.u_base = (caddr_t)&u.u_exdata;
	92	u.u_count = sizeof(u.u_exdata);
	93	u.u_offset = 0;
	94	u.u_segflg = 1;
	95	readi(ip);
	96	u.u_segflg = 0;
	97	if(u.u_error)
	98	goto bad;
	99	if (u.u_count > sizeof(u.u_exdata) - sizeof(u.u_exdata.Ux_A)
	100	&& u.u_exdata.ux_shell[0] != '#') {
	101	u.u_error = ENOEXEC;
	102	goto bad;
	103	}
	104	switch (u.u_exdata.ux_mag) {
	105
	106	case 0407:
	107	u.u_exdata.ux_dsize += u.u_exdata.ux_tsize;
	108	u.u_exdata.ux_tsize = 0;
	109	break;
	110
	111	case 0413:
	112	case 0410:
	113	if (u.u_exdata.ux_tsize == 0) {
	114	u.u_error = ENOEXEC;
	115	goto bad;
	116	}
	117	break;
	118
	119	default:
	120	if (u.u_exdata.ux_shell[0] != '#' \|\|
	121	u.u_exdata.ux_shell[1] != '!' \|\|
	122	indir) {
	123	u.u_error = ENOEXEC;
	124	goto bad;
	125	}
	126	cp = &u.u_exdata.ux_shell[2]; /* skip "#!" */
	127	while (cp < &u.u_exdata.ux_shell[SHSIZE]) {
	128	if (*cp == '\t')
	129	*cp = ' ';
	130	else if (*cp == '\n') {
	131	*cp = '\0';
	132	break;
	133	}
	134	cp++;
	135	}
	136	if (*cp != '\0') {
	137	u.u_error = ENOEXEC;
	138	goto bad;
	139	}
140	cp = &u.u_exdata.ux_shell[2];
141	while (*cp == ' ')
142	cp++;
143	u.u_dirp = cp;
144	while (cp && cp != ' ')
145	cp++;
146	sharg = NULL;
147	if (*cp) {
148	*cp++ = '\0';
149	while (*cp == ' ')
150	cp++;
151	if (*cp) {
152	bcopy((caddr_t)cp, (caddr_t)cfarg, SHSIZE);
153	sharg = cfarg;
154	}
155	}
156	bcopy((caddr_t)u.u_dbuf, (caddr_t)cfname, DIRSIZ);
157	indir = 1;
158	iput(ip);
159	ip = namei(schar, 0);
160	if (ip == NULL)
161	return;
162	goto again;
163	}
164
29dd101b BJ	165	/*
	166	* Collect arguments on "file" in swap space.
	167	*/
	168	na = 0;
	169	ne = 0;
	170	nc = 0;
	171	uap = (struct execa *)u.u_ap;
b725a0ca	172	if ((bno = rmalloc(argmap, ctod(clrnd((int) btoc(NCARGS))))) == 0) {
29dd101b BJ	173	swkill(u.u_procp, "exece");
	174	goto bad;
	175	}
	176	if (bno % CLSIZE)
b725a0ca	177	panic("execa rmalloc");
29dd101b BJ	178	if (uap->argp) for (;;) {
29dd101b BJ	179	ap = NULL;
7eeaac77 RE	180	if (na == 1 && indir) {
	181	if (sharg == NULL)
	182	ap = (int)uap->fname;
	183	} else if (na == 2 && indir && sharg != NULL)
	184	ap = (int)uap->fname;
	185	else if (uap->argp) {
29dd101b BJ	186	ap = fuword((caddr_t)uap->argp);
	187	uap->argp++;
	188	}
	189	if (ap==NULL && uap->envp) {
	190	uap->argp = NULL;
	191	if ((ap = fuword((caddr_t)uap->envp)) == NULL)
	192	break;
	193	uap->envp++;
	194	ne++;
	195	}
	196	if (ap==NULL)
	197	break;
	198	na++;
	199	if(ap == -1)
	200	u.u_error = EFAULT;
	201	do {
	202	if (nc >= NCARGS-1)
	203	u.u_error = E2BIG;
7eeaac77 RE	204	if (indir && na == 2 && sharg != NULL)
	205	c = *sharg++ & 0377;
	206	else if ((c = fubyte((caddr_t)ap++)) < 0)
29dd101b	207	u.u_error = EFAULT;
64d6118b BJ	208	if (u.u_error) {
	209	if (bp)
	210	brelse(bp);
	211	bp = 0;
29dd101b	212	goto badarg;
64d6118b	213	}
29dd101b BJ	214	if ((nc&BMASK) == 0) {
	215	if (bp)
	216	bdwrite(bp);
41888f16 BJ	217	bp = getblk(argdev,
41888f16 BJ	218	(daddr_t)(dbtofsb(bno)+(nc>>BSHIFT)));
29dd101b BJ	219	cp = bp->b_un.b_addr;
	220	}
	221	nc++;
	222	*cp++ = c;
	223	} while (c>0);
	224	}
	225	if (bp)
	226	bdwrite(bp);
	227	bp = 0;
	228	nc = (nc + NBPW-1) & ~(NBPW-1);
7eeaac77 RE	229	if (indir)
	230	bcopy((caddr_t)cfname, (caddr_t)u.u_dbuf, DIRSIZ);
	231	getxfile(ip, nc + (na+4)*NBPW, uid, gid);
29a06346	232	if (u.u_error) {
29dd101b BJ	233	badarg:
29dd101b BJ	234	for (c = 0; c < nc; c += BSIZE)
41888f16	235	if (bp = baddr(argdev, dbtofsb(bno)+(c>>BSHIFT))) {
29dd101b BJ	236	bp->b_flags \|= B_AGE; /* throw away */
	237	bp->b_flags &= ~B_DELWRI; /* cancel io */
	238	brelse(bp);
	239	bp = 0;
	240	}
	241	goto bad;
	242	}
	243
	244	/*
	245	* copy back arglist
	246	*/
	247
	248	ucp = USRSTACK - nc - NBPW;
	249	ap = ucp - naNBPW - 3NBPW;
	250	u.u_ar0[SP] = ap;
81263dba	251	(void) suword((caddr_t)ap, na-ne);
29dd101b BJ	252	nc = 0;
	253	for (;;) {
	254	ap += NBPW;
	255	if (na==ne) {
81263dba	256	(void) suword((caddr_t)ap, 0);
29dd101b BJ	257	ap += NBPW;
	258	}
	259	if (--na < 0)
	260	break;
81263dba	261	(void) suword((caddr_t)ap, ucp);
29dd101b BJ	262	do {
	263	if ((nc&BMASK) == 0) {
	264	if (bp)
	265	brelse(bp);
41888f16 BJ	266	bp = bread(argdev,
41888f16 BJ	267	(daddr_t)(dbtofsb(bno)+(nc>>BSHIFT)));
29dd101b BJ	268	bp->b_flags \|= B_AGE; /* throw away */
	269	bp->b_flags &= ~B_DELWRI; /* cancel io */
	270	cp = bp->b_un.b_addr;
	271	}
81263dba	272	(void) subyte((caddr_t)ucp++, (c = *cp++));
29dd101b BJ	273	nc++;
	274	} while(c&0377);
	275	}
81263dba BJ	276	(void) suword((caddr_t)ap, 0);
81263dba BJ	277	(void) suword((caddr_t)ucp, 0);
29dd101b BJ	278	setregs();
	279	bad:
	280	if (bp)
	281	brelse(bp);
	282	if (bno)
b725a0ca	283	rmfree(argmap, ctod(clrnd((int) btoc(NCARGS))), bno);
29dd101b BJ	284	iput(ip);
	285	}
	286
	287	/*
	288	* Read in and set up memory for executed file.
29dd101b	289	*/
7eeaac77	290	getxfile(ip, nargc, uid, gid)
29dd101b BJ	291	register struct inode *ip;
29dd101b BJ	292	{
29dd101b	293	register size_t ts, ds, ss;
7eeaac77	294	int pagi;
29dd101b	295
7eeaac77	296	if (u.u_exdata.ux_mag == 0413)
29dd101b	297	pagi = SPAGI;
7eeaac77 RE	298	else
7eeaac77 RE	299	pagi = 0;
29dd101b	300
29dd101b	301	if(u.u_exdata.ux_tsize!=0 && (ip->i_flag&ITEXT)==0 && ip->i_count!=1) {
3ca1542b BJ	302	register struct file *fp;
3ca1542b BJ	303
fb21923a	304	for (fp = file; fp < fileNFILE; fp++)
3ca1542b BJ	305	if (fp->f_inode == ip && (fp->f_flag&FWRITE)) {
	306	u.u_error = ETXTBSY;
	307	goto bad;
	308	}
29dd101b BJ	309	}
	310
	311	/*
	312	* find text and data sizes
	313	* try them out for possible
	314	* exceed of max sizes
	315	*/
	316
	317	ts = clrnd(btoc(u.u_exdata.ux_tsize));
	318	ds = clrnd(btoc((u.u_exdata.ux_dsize+u.u_exdata.ux_bsize)));
	319	ss = clrnd(SSIZE + btoc(nargc));
29a06346 BJ	320	if (chksize(ts, ds, ss))
	321	goto bad;
	322	u.u_cdmap = zdmap;
	323	u.u_csmap = zdmap;
	324	if (swpexpand(ds, ss, &u.u_cdmap, &u.u_csmap) == NULL)
	325	goto bad;
29dd101b	326
29a06346 BJ	327	/*
	328	* At this point, committed to the new image!
	329	* Release virtual memory resources of old process, and
	330	* initialize the virtual memory of the new process.
	331	* If we resulted from vfork(), instead wakeup our
	332	* parent who will set SVFDONE when he has taken back
	333	* our resources.
	334	*/
	335	u.u_prof.pr_scale = 0;
	336	if ((u.u_procp->p_flag & SVFORK) == 0)
	337	vrelvm();
	338	else {
	339	u.u_procp->p_flag &= ~SVFORK;
	340	u.u_procp->p_flag \|= SKEEP;
	341	wakeup((caddr_t)u.u_procp);
	342	while ((u.u_procp->p_flag & SVFDONE) == 0)
	343	sleep((caddr_t)u.u_procp, PZERO - 1);
	344	u.u_procp->p_flag &= ~(SVFDONE\|SKEEP);
	345	}
	346	u.u_procp->p_flag &= ~(SPAGI\|SANOM\|SUANOM\|SNUSIG);
	347	u.u_procp->p_flag \|= pagi;
	348	u.u_dmap = u.u_cdmap;
	349	u.u_smap = u.u_csmap;
	350	vgetvm(ts, ds, ss);
29dd101b	351
29a06346	352	if (pagi == 0) {
29dd101b	353	/*
29a06346	354	* Read in data segment.
29dd101b	355	*/
29a06346 BJ	356	u.u_base = (char *)ctob(ts);
	357	u.u_offset = sizeof(u.u_exdata)+u.u_exdata.ux_tsize;
	358	u.u_count = u.u_exdata.ux_dsize;
	359	readi(ip);
29dd101b	360	}
29a06346 BJ	361	xalloc(ip, pagi);
	362	if (pagi && u.u_procp->p_textp)
	363	vinifod((struct fpte *)dptopte(u.u_procp, 0),
	364	PG_FTEXT, u.u_procp->p_textp->x_iptr,
	365	1 + ts/CLSIZE, (int)btoc(u.u_exdata.ux_dsize));
	366
	367	/* THIS SHOULD BE DONE AT A LOWER LEVEL, IF AT ALL */
	368	mtpr(TBIA, 0);
	369
	370	/*
	371	* set SUID/SGID protections, if no tracing
	372	*/
	373	if ((u.u_procp->p_flag&STRC)==0) {
7eeaac77 RE	374	#ifndef MELB
	375	if(u.u_uid != 0)
	376	#endif
	377	{
	378	u.u_uid = uid;
	379	u.u_procp->p_uid = uid;
	380	}
	381	u.u_gid = gid;
29a06346 BJ	382	} else
29a06346 BJ	383	psignal(u.u_procp, SIGTRAP);
29dd101b BJ	384	u.u_tsize = ts;
	385	u.u_dsize = ds;
	386	u.u_ssize = ss;
29dd101b	387	bad:
29a06346	388	return;
29dd101b BJ	389	}
	390
	391	/*
	392	* Clear registers on exec
	393	*/
	394	setregs()
	395	{
594ebedd	396	register int (**rp)();
29dd101b	397	register i;
bdfe5b0f	398	long sigmask;
29dd101b	399
bdfe5b0f BJ	400	for(rp = &u.u_signal[0], sigmask = 1L; rp < &u.u_signal[NSIG];
	401	sigmask <<= 1, rp++) {
	402	switch (*rp) {
	403
	404	case SIG_IGN:
	405	case SIG_DFL:
	406	case SIG_HOLD:
	407	continue;
	408
	409	default:
	410	/*
99fa88a2	411	* Normal or deferring catch; revert to default.
bdfe5b0f	412	*/
99fa88a2 BJ	413	(void) spl6();
99fa88a2 BJ	414	*rp = SIG_DFL;
bdfe5b0f BJ	415	if ((int)*rp & 1)
	416	u.u_procp->p_siga0 \|= sigmask;
	417	else
	418	u.u_procp->p_siga1 &= ~sigmask;
	419	if ((int)*rp & 2)
	420	u.u_procp->p_siga1 \|= sigmask;
	421	else
	422	u.u_procp->p_siga1 &= ~sigmask;
99fa88a2	423	(void) spl0();
bdfe5b0f BJ	424	continue;
	425	}
	426	}
29dd101b BJ	427	/*
	428	for(rp = &u.u_ar0[0]; rp < &u.u_ar0[16];)
	429	*rp++ = 0;
	430	*/
	431	u.u_ar0[PC] = u.u_exdata.ux_entloc + 2; /* skip over entry mask */
	432	for(i=0; i<NOFILE; i++) {
	433	if (u.u_pofile[i]&EXCLOSE) {
	434	closef(u.u_ofile[i]);
	435	u.u_ofile[i] = NULL;
bdfe5b0f	436	u.u_pofile[i] &= ~EXCLOSE;
29dd101b	437	}
29dd101b BJ	438	}
	439	/*
	440	* Remember file name for accounting.
	441	*/
	442	u.u_acflag &= ~AFORK;
	443	bcopy((caddr_t)u.u_dbuf, (caddr_t)u.u_comm, DIRSIZ);
	444	}
	445
	446	/*
	447	* exit system call:
	448	* pass back caller's arg
	449	*/
	450	rexit()
	451	{
	452	register struct a {
	453	int rval;
	454	} *uap;
	455
	456	uap = (struct a *)u.u_ap;
	457	exit((uap->rval & 0377) << 8);
	458	}
	459
	460	/*
	461	* Release resources.
	462	* Save u. area for parent to look at.
	463	* Enter zombie state.
	464	* Wake up parent and init processes,
	465	* and dispose of children.
	466	*/
	467	exit(rv)
	468	{
	469	register int i;
	470	register struct proc p, q;
	471	register struct file *f;
	472	register int x;
	473
	474	#ifdef PGINPROF
	475	vmsizmon();
	476	#endif
	477	p = u.u_procp;
	478	p->p_flag &= ~(STRC\|SULOCK);
	479	p->p_flag \|= SWEXIT;
	480	p->p_clktim = 0;
bdfe5b0f BJ	481	(void) spl6();
	482	if ((int)SIG_IGN & 1)
	483	p->p_siga0 = ~0;
	484	else
	485	p->p_siga0 = 0;
	486	if ((int)SIG_IGN & 2)
	487	p->p_siga1 = ~0;
	488	else
99fa88a2	489	p->p_siga1 = 0;
bdfe5b0f	490	(void) spl0();
dd808ba3 BJ	491	p->p_cpticks = 0;
dd808ba3 BJ	492	p->p_pctcpu = 0;
29dd101b	493	for(i=0; i<NSIG; i++)
594ebedd	494	u.u_signal[i] = SIG_IGN;
29dd101b BJ	495	/*
	496	* Release virtual memory. If we resulted from
	497	* a vfork(), instead give the resources back to
	498	* the parent.
	499	*/
	500	if ((p->p_flag & SVFORK) == 0)
	501	vrelvm();
	502	else {
	503	p->p_flag &= ~SVFORK;
	504	wakeup((caddr_t)p);
	505	while ((p->p_flag & SVFDONE) == 0)
	506	sleep((caddr_t)p, PZERO - 1);
	507	p->p_flag &= ~SVFDONE;
	508	}
	509	for(i=0; i<NOFILE; i++) {
	510	f = u.u_ofile[i];
	511	u.u_ofile[i] = NULL;
	512	closef(f);
	513	}
	514	plock(u.u_cdir);
	515	iput(u.u_cdir);
	516	if (u.u_rdir) {
	517	plock(u.u_rdir);
	518	iput(u.u_rdir);
	519	}
054016e1	520	u.u_limit[LIM_FSIZE] = INFINITY;
29dd101b BJ	521	acct();
	522	vrelpt(u.u_procp);
	523	vrelu(u.u_procp, 0);
	524	multprog--;
41888f16	525	/* spl7(); /* clock will get mad because of overlaying */
29dd101b	526	p->p_stat = SZOMB;
42343c0f	527	noproc = 1;
29dd101b BJ	528	i = PIDHASH(p->p_pid);
	529	x = p - proc;
	530	if (pidhash[i] == x)
	531	pidhash[i] = p->p_idhash;
	532	else {
	533	for (i = pidhash[i]; i != 0; i = proc[i].p_idhash)
	534	if (proc[i].p_idhash == x) {
	535	proc[i].p_idhash = p->p_idhash;
	536	goto done;
	537	}
	538	panic("exit");
	539	}
9c82b9fd BJ	540	if (p->p_pid == 1)
9c82b9fd BJ	541	panic("init died");
29dd101b BJ	542	done:
	543	((struct xproc )p)->xp_xstat = rv; / overlay */
	544	((struct xproc )p)->xp_vm = u.u_vm; / overlay */
	545	vmsadd(&((struct xproc *)p)->xp_vm, &u.u_cvm);
86fd527f	546	for(q = proc; q < procNPROC; q++)
bdfe5b0f BJ	547	if(q->p_pptr == p) {
bdfe5b0f BJ	548	q->p_pptr = &proc[1];
29dd101b	549	q->p_ppid = 1;
bdfe5b0f BJ	550	wakeup((caddr_t)&proc[1]);
bdfe5b0f BJ	551	/*
0dde1c43	552	* Traced processes are killed
bdfe5b0f	553	* since their existence means someone is screwing up.
62bac59f	554	* Stopped processes are sent a hangup and a continue.
0dde1c43 BJ	555	* This is designed to be ``safe'' for setuid
	556	* processes since they must be willing to tolerate
	557	* hangups anyways.
bdfe5b0f	558	*/
0dde1c43	559	if (q->p_flag&STRC) {
bdfe5b0f BJ	560	q->p_flag &= ~STRC;
bdfe5b0f BJ	561	psignal(q, SIGKILL);
0dde1c43 BJ	562	} else if (q->p_stat == SSTOP) {
	563	psignal(q, SIGHUP);
	564	psignal(q, SIGCONT);
bdfe5b0f	565	}
8643403f BJ	566	/*
8643403f BJ	567	* Protect this process from future
62bac59f BJ	568	* tty signals, clear TSTP/TTIN/TTOU if pending,
62bac59f BJ	569	* and set SDETACH bit on procs.
8643403f	570	*/
934e4ecf	571	(void) spgrp(q, -1);
29dd101b	572	}
bdfe5b0f BJ	573	wakeup((caddr_t)p->p_pptr);
bdfe5b0f BJ	574	psignal(p->p_pptr, SIGCHLD);
29dd101b BJ	575	swtch();
	576	}
	577
	578	wait()
	579	{
bdfe5b0f BJ	580	struct vtimes vm;
bdfe5b0f BJ	581	struct vtimes *vp;
29dd101b	582
bdfe5b0f BJ	583	if ((u.u_ar0[PS] & PSL_ALLCC) != PSL_ALLCC) {
	584	wait1(0, (struct vtimes *)0);
	585	return;
	586	}
	587	vp = (struct vtimes *)u.u_ar0[R1];
	588	wait1(u.u_ar0[R0], &vm);
	589	if (u.u_error)
	590	return;
	591	(void) copyout((caddr_t)&vm, (caddr_t)vp, sizeof (struct vtimes));
29dd101b BJ	592	}
	593
	594	/*
	595	* Wait system call.
	596	* Search for a terminated (zombie) child,
	597	* finally lay it to rest, and collect its status.
	598	* Look also for stopped (traced) children,
	599	* and pass back status from them.
	600	*/
bdfe5b0f BJ	601	wait1(options, vp)
bdfe5b0f BJ	602	register options;
29dd101b BJ	603	struct vtimes *vp;
	604	{
	605	register f;
	606	register struct proc *p;
	607
	608	f = 0;
29dd101b	609	loop:
86fd527f	610	for(p = proc; p < procNPROC; p++)
bdfe5b0f	611	if(p->p_pptr == u.u_procp) {
29dd101b BJ	612	f++;
	613	if(p->p_stat == SZOMB) {
	614	u.u_r.r_val1 = p->p_pid;
	615	u.u_r.r_val2 = ((struct xproc *)p)->xp_xstat;
	616	((struct xproc *)p)->xp_xstat = 0;
	617	if (vp)
	618	vp = ((struct xproc )p)->xp_vm;
	619	vmsadd(&u.u_cvm, &((struct xproc *)p)->xp_vm);
	620	((struct xproc *)p)->xp_vm = zvms;
	621	p->p_stat = NULL;
	622	p->p_pid = 0;
	623	p->p_ppid = 0;
bdfe5b0f	624	p->p_pptr = 0;
29dd101b	625	p->p_sig = 0;
bdfe5b0f BJ	626	p->p_siga0 = 0;
bdfe5b0f BJ	627	p->p_siga1 = 0;
29dd101b BJ	628	p->p_pgrp = 0;
	629	p->p_flag = 0;
	630	p->p_wchan = 0;
bdfe5b0f	631	p->p_cursig = 0;
29dd101b BJ	632	return;
29dd101b BJ	633	}
bdfe5b0f BJ	634	if (p->p_stat == SSTOP && (p->p_flag&SWTED)==0 &&
	635	(p->p_flag&STRC \|\| options&WUNTRACED)) {
	636	p->p_flag \|= SWTED;
	637	u.u_r.r_val1 = p->p_pid;
	638	u.u_r.r_val2 = (p->p_cursig<<8) \| WSTOPPED;
	639	return;
29dd101b BJ	640	}
29dd101b BJ	641	}
bdfe5b0f BJ	642	if (f==0) {
	643	u.u_error = ECHILD;
	644	return;
	645	}
	646	if (options&WNOHANG) {
	647	u.u_r.r_val1 = 0;
	648	return;
	649	}
29a06346	650	if ((u.u_procp->p_flag&SNUSIG) && setjmp(u.u_qsav)) {
bdfe5b0f BJ	651	u.u_eosys = RESTARTSYS;
bdfe5b0f BJ	652	return;
29dd101b	653	}
bdfe5b0f BJ	654	sleep((caddr_t)u.u_procp, PWAIT);
bdfe5b0f BJ	655	goto loop;
29dd101b BJ	656	}
	657
	658	/*
	659	* fork system call.
	660	*/
	661	fork()
	662	{
	663
	664	u.u_cdmap = zdmap;
	665	u.u_csmap = zdmap;
	666	if (swpexpand(u.u_dsize, u.u_ssize, &u.u_cdmap, &u.u_csmap) == 0) {
	667	u.u_r.r_val2 = 0;
	668	return;
	669	}
	670	fork1(0);
	671	}
	672
	673	fork1(isvfork)
	674	{
	675	register struct proc p1, p2;
	676	register a;
	677
	678	a = 0;
	679	p2 = NULL;
86fd527f	680	for(p1 = proc; p1 < procNPROC; p1++) {
29dd101b BJ	681	if (p1->p_stat==NULL && p2==NULL)
	682	p2 = p1;
	683	else {
	684	if (p1->p_uid==u.u_uid && p1->p_stat!=NULL)
	685	a++;
	686	}
	687	}
	688	/*
	689	* Disallow if
	690	* No processes at all;
	691	* not su and too many procs owned; or
	692	* not su and would take last slot.
	693	*/
62901f34 BJ	694	if (p2==NULL)
62901f34 BJ	695	tablefull("proc");
86fd527f	696	if (p2==NULL \|\| (u.u_uid!=0 && (p2==procNPROC-1 \|\| a>MAXUPRC))) {
29dd101b BJ	697	u.u_error = EAGAIN;
29dd101b BJ	698	if (!isvfork) {
81263dba BJ	699	(void) vsexpand(0, &u.u_cdmap, 1);
81263dba BJ	700	(void) vsexpand(0, &u.u_csmap, 1);
29dd101b BJ	701	}
	702	goto out;
	703	}
	704	p1 = u.u_procp;
	705	if(newproc(isvfork)) {
	706	u.u_r.r_val1 = p1->p_pid;
	707	u.u_r.r_val2 = 1; /* child */
	708	u.u_start = time;
	709	u.u_acflag = AFORK;
	710	return;
	711	}
	712	u.u_r.r_val1 = p2->p_pid;
	713
	714	out:
	715	u.u_r.r_val2 = 0;
	716	}
	717
	718	/*
	719	* break system call.
	720	* -- bad planning: "break" is a dirty word in C.
	721	*/
	722	sbreak()
	723	{
	724	struct a {
	725	char *nsiz;
	726	};
	727	register int n, d;
	728
	729	/*
	730	* set n to new data size
	731	* set d to new-old
	732	*/
	733
	734	n = btoc(((struct a *)u.u_ap)->nsiz);
	735	if (!u.u_sep)
	736	n -= ctos(u.u_tsize) * stoc(1);
	737	if (n < 0)
	738	n = 0;
	739	d = clrnd(n - u.u_dsize);
5290ec92	740	if (ctob(u.u_dsize+d) > u.u_limit[LIM_DATA]) {
054016e1 BJ	741	u.u_error = ENOMEM;
	742	return;
	743	}
29dd101b BJ	744	if (chksize(u.u_tsize, u.u_dsize+d, u.u_ssize))
	745	return;
	746	if (swpexpand(u.u_dsize+d, u.u_ssize, &u.u_dmap, &u.u_smap)==0)
	747	return;
	748	expand(d, P0BR);
	749	}