4.1cBSD/a/sys/sys/kern_sig.c
/* kern_sig.c 5.15 82/12/28 */
#include "../machine/reg.h"
#include "../machine/pte.h"
#include "../machine/psl.h"
#include "../h/param.h"
#include "../h/systm.h"
#include "../h/dir.h"
#include "../h/user.h"
#include "../h/inode.h"
#include "../h/proc.h"
#include "../h/timeb.h"
#include "../h/times.h"
#include "../h/conf.h"
#include "../h/buf.h"
#include "../h/mount.h"
#include "../h/text.h"
#include "../h/seg.h"
#include "../h/vm.h"
#include "../h/acct.h"
#include "../h/uio.h"
#include "../h/kernel.h"
#include "../h/nami.h"
/* KILL CODE SHOULDNT KNOW ABOUT PROCESS INTERNALS !?! */
sigvec()
{
}
sigblock()
{
}
sigsetmask()
{
}
sigpause()
{
}
sigstack()
{
}
#ifdef notdef
kill()
{
}
#endif
/* TEMPORARY */
killpg()
{
register struct a {
int pgrp;
int signo;
} *uap = (struct a *)u.u_ap;
u.u_error = okill1(1, uap->signo, uap->pgrp);
}
/* BEGIN DEFUNCT */
okill()
{
register struct a {
int pid;
int signo;
} *uap = (struct a *)u.u_ap;
u.u_error = okill1(uap->signo < 0,
uap->signo < 0 ? -uap->signo : uap->signo, uap->pid);
}
okill1(ispgrp, signo, who)
int ispgrp, signo, who;
{
register struct proc *p;
int f, priv = 0;
if (signo == 0 || signo > NSIG)
return (EINVAL);
if (who > 0 && !ispgrp) {
p = pfind(who);
if (p == 0 || u.u_uid && u.u_uid != p->p_uid)
return (ESRCH);
psignal(p, signo);
return (0);
}
if (who == -1 && u.u_uid == 0)
priv++, who = 0, ispgrp = 1; /* like sending to pgrp */
else if (who == 0) {
/*
* Zero process id means send to my process group.
*/
ispgrp = 1;
who = u.u_procp->p_pgrp;
if (who == 0)
return (EINVAL);
}
for (f = 0, p = proc; p < procNPROC; p++) {
if (p->p_stat == NULL)
continue;
if (!ispgrp) {
if (p->p_pid != who)
continue;
} else if (p->p_pgrp != who && priv == 0 || p->p_ppid == 0 ||
(p->p_flag&SSYS) || (priv && p == u.u_procp))
continue;
if (u.u_uid != 0 && u.u_uid != p->p_uid &&
(signo != SIGCONT || !inferior(p)))
continue;
f++;
psignal(p, signo);
}
return (f == 0? ESRCH : 0);
}
ossig()
{
register int (*f)();
struct a {
int signo;
int (*fun)();
} *uap;
register struct proc *p = u.u_procp;
register a;
long sigmask;
uap = (struct a *)u.u_ap;
a = uap->signo & SIGNUMMASK;
f = uap->fun;
if (a<=0 || a>=NSIG || a==SIGKILL || a==SIGSTOP ||
a==SIGCONT && (f == SIG_IGN || f == SIG_HOLD)) {
u.u_error = EINVAL;
return;
}
if ((uap->signo &~ SIGNUMMASK) || (f != SIG_DFL && f != SIG_IGN &&
SIGISDEFER(f)))
u.u_procp->p_flag |= SNUSIG;
/*
* Don't clobber registers if we are to simulate
* a ret+rti.
*/
if ((uap->signo&SIGDORTI) == 0)
u.u_r.r_val1 = (int)u.u_signal[a];
/*
* Change setting atomically.
*/
(void) spl6();
sigmask = 1L << (a-1);
if (f == SIG_IGN)
p->p_sig &= ~sigmask; /* never to be seen again */
u.u_signal[a] = f;
if (f != SIG_DFL && f != SIG_IGN && f != SIG_HOLD)
f = SIG_CATCH;
if ((int)f & 1)
p->p_siga0 |= sigmask;
else
p->p_siga0 &= ~sigmask;
if ((int)f & 2)
p->p_siga1 |= sigmask;
else
p->p_siga1 &= ~sigmask;
(void) spl0();
/*
* Now handle options.
*/
if (uap->signo & SIGDOPAUSE) {
/*
* Simulate a PDP11 style wait instrution which
* atomically lowers priority, enables interrupts
* and hangs.
*/
opause();
/*NOTREACHED*/
}
if (uap->signo & SIGDORTI)
u.u_eosys = SIMULATERTI;
}
/*
* Send the specified signal to
* all processes with 'pgrp' as
* process group.
* Called by tty.c for quits and
* interrupts.
*/
gsignal(pgrp, sig)
register int pgrp;
{
register struct proc *p;
if (pgrp == 0)
return;
for(p = proc; p < procNPROC; p++)
if (p->p_pgrp == pgrp)
psignal(p, sig);
}
/*
* Send the specified signal to
* the specified process.
*/
psignal(p, sig)
register struct proc *p;
register int sig;
{
register int s;
register int (*action)();
long sigmask;
if ((unsigned)sig >= NSIG)
return;
sigmask = (1L << (sig-1));
/*
* If proc is traced, always give parent a chance.
* Otherwise get the signal action from the bits in the proc table.
*/
if (p->p_flag & STRC)
action = SIG_DFL;
else {
s = (p->p_siga1&sigmask) != 0;
s <<= 1;
s |= (p->p_siga0&sigmask) != 0;
action = (int(*)())s;
/*
* If the signal is ignored, we forget about it immediately.
*/
if (action == SIG_IGN)
return;
}
#define mask(sig) (1<<(sig-1))
#define stops (mask(SIGSTOP)|mask(SIGTSTP)|mask(SIGTTIN)|mask(SIGTTOU))
if (sig) {
p->p_sig |= sigmask;
switch (sig) {
case SIGTERM:
if ((p->p_flag&STRC) != 0 || action != SIG_DFL)
break;
/* fall into ... */
case SIGKILL:
if (p->p_nice > NZERO)
p->p_nice = NZERO;
break;
case SIGCONT:
p->p_sig &= ~stops;
break;
case SIGSTOP:
case SIGTSTP:
case SIGTTIN:
case SIGTTOU:
p->p_sig &= ~mask(SIGCONT);
break;
}
}
#undef mask
#undef stops
/*
* Defer further processing for signals which are held.
*/
if (action == SIG_HOLD)
return;
s = spl6();
switch (p->p_stat) {
case SSLEEP:
/*
* If process is sleeping at negative priority
* we can't interrupt the sleep... the signal will
* be noticed when the process returns through
* trap() or syscall().
*/
if (p->p_pri <= PZERO)
goto out;
/*
* Process is sleeping and traced... make it runnable
* so it can discover the signal in issig() and stop
* for the parent.
*/
if (p->p_flag&STRC)
goto run;
switch (sig) {
case SIGSTOP:
case SIGTSTP:
case SIGTTIN:
case SIGTTOU:
/*
* These are the signals which by default
* stop a process.
*/
if (action != SIG_DFL)
goto run;
/*
* Don't clog system with children of init
* stopped from the keyboard.
*/
if (sig != SIGSTOP && p->p_pptr == &proc[1]) {
psignal(p, SIGKILL);
p->p_sig &= ~sigmask;
splx(s);
return;
}
/*
* If a child in vfork(), stopping could
* cause deadlock.
*/
if (p->p_flag&SVFORK)
goto out;
p->p_sig &= ~sigmask;
p->p_cursig = sig;
stop(p);
goto out;
case SIGIO:
case SIGURG:
case SIGCHLD:
/*
* These signals are special in that they
* don't get propogated... if the process
* isn't interested, forget it.
*/
if (action != SIG_DFL)
goto run;
p->p_sig &= ~sigmask; /* take it away */
goto out;
default:
/*
* All other signals cause the process to run
*/
goto run;
}
/*NOTREACHED*/
case SSTOP:
/*
* If traced process is already stopped,
* then no further action is necessary.
*/
if (p->p_flag&STRC)
goto out;
switch (sig) {
case SIGKILL:
/*
* Kill signal always sets processes running.
*/
goto run;
case SIGCONT:
/*
* If the process catches SIGCONT, let it handle
* the signal itself. If it isn't waiting on
* an event, then it goes back to run state.
* Otherwise, process goes back to sleep state.
*/
if (action != SIG_DFL || p->p_wchan == 0)
goto run;
p->p_stat = SSLEEP;
goto out;
case SIGSTOP:
case SIGTSTP:
case SIGTTIN:
case SIGTTOU:
/*
* Already stopped, don't need to stop again.
* (If we did the shell could get confused.)
*/
p->p_sig &= ~sigmask; /* take it away */
goto out;
default:
/*
* If process is sleeping interruptibly, then
* unstick it so that when it is continued
* it can look at the signal.
* But don't setrun the process as its not to
* be unstopped by the signal alone.
*/
if (p->p_wchan && p->p_pri > PZERO)
unsleep(p);
goto out;
}
/*NOTREACHED*/
default:
/*
* SRUN, SIDL, SZOMB do nothing with the signal,
* other than kicking ourselves if we are running.
* It will either never be noticed, or noticed very soon.
*/
if (p == u.u_procp && !noproc)
#include "../vax/mtpr.h"
aston();
goto out;
}
/*NOTREACHED*/
run:
/*
* Raise priority to at least PUSER.
*/
if (p->p_pri > PUSER)
if ((p != u.u_procp || noproc) && p->p_stat == SRUN &&
(p->p_flag & SLOAD)) {
remrq(p);
p->p_pri = PUSER;
setrq(p);
} else
p->p_pri = PUSER;
setrun(p);
out:
splx(s);
}
/*
* Returns true if the current
* process has a signal to process.
* The signal to process is put in p_cursig.
* This is asked at least once each time a process enters the
* system (though this can usually be done without actually
* calling issig by checking the pending signal masks.)
* A signal does not do anything
* directly to a process; it sets
* a flag that asks the process to
* do something to itself.
*/
issig()
{
register struct proc *p;
register int sig;
long sigbits;
long sigmask;
p = u.u_procp;
for (;;) {
sigbits = p->p_sig;
if ((p->p_flag&STRC) == 0)
sigbits &= ~p->p_ignsig;
if (p->p_flag&SVFORK)
#define bit(a) (1<<(a-1))
sigbits &= ~(bit(SIGSTOP)|bit(SIGTSTP)|bit(SIGTTIN)|bit(SIGTTOU));
if (sigbits == 0)
break;
sig = ffs((int)sigbits);
sigmask = 1L << (sig-1);
p->p_sig &= ~sigmask; /* take the signal! */
p->p_cursig = sig;
if (p->p_flag&STRC && (p->p_flag&SVFORK)==0) {
/*
* If traced, always stop, and stay
* stopped until released by the parent.
*/
do {
stop(p);
swtch();
} while (!procxmt() && p->p_flag&STRC);
/*
* If the traced bit got turned off,
* then put the signal taken above back into p_sig
* and go back up to the top to rescan signals.
* This ensures that siga0 and u_signal are consistent.
*/
if ((p->p_flag&STRC) == 0) {
p->p_sig |= sigmask;
continue;
}
/*
* If parent wants us to take the signal,
* then it will leave it in p->p_cursig;
* otherwise we just look for signals again.
*/
sig = p->p_cursig;
if (sig == 0)
continue;
}
switch (u.u_signal[sig]) {
case SIG_DFL:
/*
* Don't take default actions on system processes.
*/
if (p->p_ppid == 0)
break;
switch (sig) {
case SIGTSTP:
case SIGTTIN:
case SIGTTOU:
/*
* Children of init aren't allowed to stop
* on signals from the keyboard.
*/
if (p->p_pptr == &proc[1]) {
psignal(p, SIGKILL);
continue;
}
/* fall into ... */
case SIGSTOP:
if (p->p_flag&STRC)
continue;
stop(p);
swtch();
continue;
case SIGCONT:
case SIGCHLD:
/*
* These signals are normally not
* sent if the action is the default.
*/
continue; /* == ignore */
default:
goto send;
}
/*NOTREACHED*/
case SIG_HOLD:
case SIG_IGN:
/*
* Masking above should prevent us
* ever trying to take action on a held
* or ignored signal, unless process is traced.
*/
if ((p->p_flag&STRC) == 0)
printf("issig\n");
continue;
default:
/*
* This signal has an action, let
* psig process it.
*/
goto send;
}
/*NOTREACHED*/
}
/*
* Didn't find a signal to send.
*/
p->p_cursig = 0;
return (0);
send:
/*
* Let psig process the signal.
*/
return (sig);
}
/*
* Put the argument process into the stopped
* state and notify the parent via wakeup and/or signal.
*/
stop(p)
register struct proc *p;
{
p->p_stat = SSTOP;
p->p_flag &= ~SWTED;
wakeup((caddr_t)p->p_pptr);
/*
* Avoid sending signal to parent if process is traced
*/
if (p->p_flag&STRC)
return;
psignal(p->p_pptr, SIGCHLD);
}
/*
* Perform the action specified by
* the current signal.
* The usual sequence is:
* if (issig())
* psig();
* The signal bit has already been cleared by issig,
* and the current signal number stored in p->p_cursig.
*/
psig()
{
register struct proc *rp = u.u_procp;
register int n = rp->p_cursig;
long sigmask = 1L << (n-1);
register int (*action)();
if (rp->p_cursig == 0)
panic("psig");
action = u.u_signal[n];
if (action != SIG_DFL) {
if (action == SIG_IGN || action == SIG_HOLD)
panic("psig action");
u.u_error = 0;
if (n != SIGILL && n != SIGTRAP)
u.u_signal[n] = 0;
/*
* If this catch value indicates automatic holding of
* subsequent signals, set the hold value.
*/
if (SIGISDEFER(action)) {
(void) spl6();
if ((int)SIG_HOLD & 1)
rp->p_siga0 |= sigmask;
else
rp->p_siga0 &= ~sigmask;
if ((int)SIG_HOLD & 2)
rp->p_siga1 |= sigmask;
else
rp->p_siga1 &= ~sigmask;
u.u_signal[n] = SIG_HOLD;
(void) spl0();
action = SIGUNDEFER(action);
}
u.u_ru.ru_nsignals++;
sendsig(action, n);
rp->p_cursig = 0;
return;
}
u.u_acflag |= AXSIG;
switch (n) {
case SIGILL:
case SIGIOT:
case SIGBUS:
case SIGQUIT:
case SIGTRAP:
case SIGEMT:
case SIGFPE:
case SIGSEGV:
case SIGSYS:
u.u_arg[0] = n;
if (core())
n += 0200;
}
exit(n);
}
#ifdef unneeded
int corestop = 0;
#endif
/*
* Create a core image on the file "core"
* If you are looking for protection glitches,
* there are probably a wealth of them here
* when this occurs to a suid command.
*
* It writes UPAGES block of the
* user.h area followed by the entire
* data+stack segments.
*/
core()
{
register struct inode *ip;
extern schar();
#ifdef unneeded
if (corestop) {
int i;
for (i = 0; i < 10; i++)
if (u.u_comm[i])
putchar(u.u_comm[i], 0);
printf(", uid %d\n", u.u_uid);
if (corestop&2)
asm("halt");
}
#endif
if (u.u_uid != u.u_ruid)
return (0);
if (ctob(UPAGES+u.u_dsize+u.u_ssize) >=
u.u_rlimit[RLIMIT_CORE].rlim_cur)
return (0);
u.u_error = 0;
u.u_dirp = "core";
ip = namei(schar, CREATE, 1);
if (ip == NULL) {
if (u.u_error)
return (0);
ip = maknode(0666);
if (ip==NULL)
return (0);
}
if (access(ip, IWRITE) ||
(ip->i_mode&IFMT) != IFREG ||
ip->i_nlink != 1) {
u.u_error = EFAULT;
goto out;
}
itrunc(ip, (u_long)0);
u.u_acflag |= ACORE;
/* if (u.u_error == 0) */
u.u_error = rdwri(UIO_WRITE, ip,
(caddr_t)&u,
ctob(UPAGES),
0, 1, (int *)0);
if (u.u_error == 0)
u.u_error = rdwri(UIO_WRITE, ip,
(caddr_t)ctob(dptov(u.u_procp, 0)),
ctob(u.u_dsize),
ctob(UPAGES), 0, (int *)0);
if (u.u_error == 0)
u.u_error = rdwri(UIO_WRITE, ip,
(caddr_t)ctob(sptov(u.u_procp, u.u_ssize - 1)),
ctob(u.u_ssize),
ctob(UPAGES)+ctob(u.u_dsize), 0, (int *)0);
out:
iput(ip);
return (u.u_error == 0);
}