32V/usr/src/sys/sys/sys1.c
#include "../h/param.h"
#include "../h/systm.h"
#include "../h/uba.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 "../h/page.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, bno, ucp, ap, c;
struct inode *ip;
if ((ip = namei(uchar, 0)) == NULL)
return;
bno = 0;
bp = 0;
if(access(ip, IEXEC))
goto bad;
if((ip->i_mode & IFMT) != IFREG ||
(ip->i_mode & (IEXEC|(IEXEC>>3)|(IEXEC>>6))) == 0) {
u.u_error = EACCES;
goto bad;
}
/*
* Collect arguments on "file" in swap space.
*/
na = 0;
ne = 0;
nc = 0;
uap = (struct execa *)u.u_ap;
if ((bno = malloc(swapmap,(NCARGS+BSIZE-1)/BSIZE)) == 0)
panic("Out of swap");
if (uap->argp) for (;;) {
ap = NULL;
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 ((c = fubyte((caddr_t)ap++)) < 0)
u.u_error = EFAULT;
if (u.u_error)
goto bad;
if ((nc&BMASK) == 0) {
if (bp)
bawrite(bp);
bp = getblk(swapdev, swplo+bno+(nc>>BSHIFT));
cp = bp->b_un.b_addr;
}
nc++;
*cp++ = c;
} while (c>0);
}
if (bp)
bawrite(bp);
bp = 0;
nc = (nc + NBPW-1) & ~(NBPW-1);
if (getxfile(ip, nc) || u.u_error)
goto bad;
/*
* copy back arglist
*/
ucp = USRSTACK - nc - NBPW;
ap = ucp - na*NBPW - 3*NBPW;
u.u_ar0[SP] = ap;
suword((caddr_t)ap, na-ne);
nc = 0;
for (;;) {
ap += NBPW;
if (na==ne) {
suword((caddr_t)ap, 0);
ap += NBPW;
}
if (--na < 0)
break;
suword((caddr_t)ap, ucp);
do {
if ((nc&BMASK) == 0) {
if (bp)
brelse(bp);
bp = bread(swapdev, swplo+bno+(nc>>BSHIFT));
cp = bp->b_un.b_addr;
}
subyte((caddr_t)ucp++, (c = *cp++));
nc++;
} while(c&0377);
}
suword((caddr_t)ap, 0);
suword((caddr_t)ucp, 0);
setregs();
bad:
if (bp)
brelse(bp);
if(bno)
mfree(swapmap, (NCARGS+BSIZE-1)/BSIZE, bno);
iput(ip);
}
/*
* Read in and set up memory for executed file.
* Zero return is normal;
* non-zero means only the text is being replaced
*/
getxfile(ip, nargc)
register struct inode *ip;
{
register unsigned ds;
register sep;
register struct pt_entry *ptaddr;
register unsigned ts, ss;
register i, overlay;
/*
* read in first few bytes
* of file for segment
* sizes:
* ux_mag = 407/410/411/405
* 407 is plain executable
* 410 is RO text
* 411 is separated ID
* 405 is overlaid text
*/
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!=0) {
u.u_error = ENOEXEC;
goto bad;
}
sep = 0;
overlay = 0;
if(u.u_exdata.ux_mag == 0407) {
u.u_exdata.ux_dsize += u.u_exdata.ux_tsize;
u.u_exdata.ux_tsize = 0;
} else if (u.u_exdata.ux_mag == 0411)
sep++;
else if (u.u_exdata.ux_mag == 0405)
overlay++;
else if (u.u_exdata.ux_mag != 0410) {
u.u_error = ENOEXEC;
goto bad;
}
if(u.u_exdata.ux_tsize!=0 && (ip->i_flag&ITEXT)==0 && ip->i_count!=1) {
u.u_error = ETXTBSY;
goto bad;
}
/*
* find text and data sizes
* try them out for possible
* exceed of max sizes
*/
ts = btoc(u.u_exdata.ux_tsize);
ds = btoc(u.u_exdata.ux_dsize + u.u_exdata.ux_bsize);
ss = SSIZE + btoc(nargc);
if (overlay) {
if (u.u_sep==0 && ctos(ts) != ctos(u.u_tsize) || nargc) {
u.u_error = ENOMEM;
goto bad;
}
ds = u.u_dsize;
ss = u.u_ssize;
sep = u.u_sep;
xfree();
xalloc(ip);
u.u_ar0[PC] = u.u_exdata.ux_entloc + 2; /* skip over entry mask */
} else {
if(chksize(ts, ds, ss))
goto bad;
/*
* allocate and clear core
* at this point, committed
* to the new image
*/
u.u_prof.pr_scale = 0;
xfree();
memfree(mfpr(P0BR) + 4*u.u_tsize,u.u_dsize); /* free old data area */
memfree(mfpr(P1BR) + 4*mfpr(P1LR),u.u_ssize); /* free stack */
u.u_procp->p_size -= u.u_dsize + u.u_ssize;
u.u_dsize = 0;
u.u_ssize = ss;
mtpr(P0LR,ts);
u.u_pcb.pcb_p0lr = ts | 0x04000000; /* also set ast level */
mtpr(P1LR,0x200000);
u.u_pcb.pcb_p1lr = 0x200000;
u.u_procp->p_tsize = ts; /* save prospective text size for swapin */
u.u_tsize = ts;
expand(ss,P1BR);
u.u_dsize = ds;
expand(ds,P0BR);
/* mtpr(TBIA,0); */
ptaddr = (struct pt_entry *)mfpr(P0BR);
ptaddr += ts + (u.u_exdata.ux_dsize)/512;
i = ds - (u.u_exdata.ux_dsize/512);
while (--i >= 0) {
clearseg(ptaddr->pg_pfnum); /* clear bss segment */
ptaddr++;
}
ptaddr = (struct pt_entry *)(mfpr(P1BR) + 4*mfpr(P1LR));
for(i=ss; --i>=0; ) {
clearseg(ptaddr->pg_pfnum); /* clear stack */
ptaddr++;
}
xalloc(ip);
mtpr(TBIA,1);
/*
* read in data segment
*/
chgprot(0,0,RO); /* protect the stack */
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);
chgprot(0,0,RW); /* unprotect the stack */
/*
* set SUID/SGID protections, if no tracing
*/
if ((u.u_procp->p_flag&STRC)==0) {
if(ip->i_mode&ISUID)
if(u.u_uid != 0) {
u.u_uid = ip->i_uid;
u.u_procp->p_uid = ip->i_uid;
}
if(ip->i_mode&ISGID)
u.u_gid = ip->i_gid;
} else
psignal(u.u_procp, SIGTRC);
}
u.u_tsize = ts;
u.u_dsize = ds;
u.u_ssize = ss;
u.u_sep = sep;
bad:
return(overlay);
}
/*
* Clear registers on exec
*/
setregs()
{
register int *rp;
register char *cp;
register i;
for(rp = &u.u_signal[0]; rp < &u.u_signal[NSIG]; rp++)
if((*rp & 1) == 0)
*rp = 0;
/*
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;
extern int Umap[];
int ftable[UPAGES + MAXUMEM/128];
p = u.u_procp;
p->p_flag &= ~(STRC|SULOCK);
p->p_clktim = 0;
for(i=0; i<NSIG; i++)
u.u_signal[i] = 1;
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);
}
xfree();
acct();
/* free data, stack, u-area, and page-tables */
memfree((int *)&u + UPAGES*128 + u.u_tsize, u.u_dsize);
memfree(((int *)&u) + USIZE*128 - u.u_ssize, u.u_ssize);
for(i=USIZE; --i>=0; )
ftable[i] = Umap[i];
memfree(ftable, USIZE);
p->p_stat = SZOMB;
((struct xproc *)p)->xp_xstat = rv;
((struct xproc *)p)->xp_utime = u.u_cutime + u.u_utime;
((struct xproc *)p)->xp_stime = u.u_cstime + u.u_stime;
for(q = &proc[0]; q < &proc[NPROC]; q++)
if(q->p_ppid == p->p_pid) {
wakeup((caddr_t)&proc[1]);
q->p_ppid = 1;
if (q->p_stat==SSTOP)
setrun(q);
}
for(q = &proc[0]; q < &proc[NPROC]; q++)
if(p->p_ppid == q->p_pid) {
wakeup((caddr_t)q);
swtch();
/* no return */
}
swtch();
}
/*
* 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.
*/
wait()
{
register f;
register struct proc *p;
f = 0;
loop:
for(p = &proc[0]; p < &proc[NPROC]; p++)
if(p->p_ppid == u.u_procp->p_pid) {
f++;
if(p->p_stat == SZOMB) {
u.u_r.r_val1 = p->p_pid;
u.u_r.r_val2 = ((struct xproc *)p)->xp_xstat;
u.u_cutime += ((struct xproc *)p)->xp_utime;
u.u_cstime += ((struct xproc *)p)->xp_stime;
p->p_stat = NULL;
p->p_pid = 0;
p->p_ppid = 0;
p->p_sig = 0;
p->p_pgrp = 0;
p->p_flag = 0;
p->p_wchan = 0;
return;
}
if(p->p_stat == SSTOP) {
if((p->p_flag&SWTED) == 0) {
p->p_flag |= SWTED;
u.u_r.r_val1 = p->p_pid;
u.u_r.r_val2 = (fsig(p)<<8) | 0177;
return;
}
continue;
}
}
if(f) {
sleep((caddr_t)u.u_procp, PWAIT);
goto loop;
}
u.u_error = ECHILD;
}
/*
* fork system call.
*/
fork()
{
register struct proc *p1, *p2;
register a;
/*
* Make sure there's enough swap space for max
* core image, thus reducing chances of running out
*/
if ((a = malloc(swapmap, ctod(MAXMEM))) == 0) {
u.u_error = ENOMEM;
goto out;
}
mfree(swapmap, ctod(MAXMEM), a);
a = 0;
p2 = NULL;
for(p1 = &proc[0]; p1 < &proc[NPROC]; 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 || (u.u_uid!=0 && (p2==&proc[NPROC-1] || a>MAXUPRC))) {
u.u_error = EAGAIN;
goto out;
}
p1 = u.u_procp;
if(newproc()) {
u.u_r.r_val1 = p1->p_pid;
u.u_r.r_val2 = 1; /* child */
u.u_start = time;
u.u_cstime = 0;
u.u_stime = 0;
u.u_cutime = 0;
u.u_utime = 0;
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 n, d;
register struct pt_entry *ptaddr;
/*
* 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 = n - u.u_dsize;
if(chksize(u.u_tsize, u.u_dsize+d, u.u_ssize))
return;
u.u_dsize += d;
expand(d,P0BR);
if (d>0) { /* bigger */
ptaddr = (struct pt_entry *)mfpr(P0BR);
ptaddr += u.u_tsize + u.u_dsize - d; /* point at first new page */
while(d--)
clearseg(ptaddr++->pg_pfnum);
}
}