/* * Copyright (c) 2000 Apple Computer, Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * The contents of this file constitute Original Code as defined in and * are subject to the Apple Public Source License Version 1.1 (the * "License"). You may not use this file except in compliance with the * License. Please obtain a copy of the License at * http://www.apple.com/publicsource and read it before using this file. * * This Original Code and all software distributed under the License are * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the * License for the specific language governing rights and limitations * under the License. * * @APPLE_LICENSE_HEADER_END@ */ /* Copyright (c) 1995-1998 Apple Computer, Inc. All Rights Reserved */ /* * Copyright (c) 1982, 1986, 1989, 1991, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94 */ #define SIGPROP /* include signal properties table */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* for coredump */ #include /* for APC support */ #include #include void stop __P((struct proc *p)); int cansignal __P((struct proc *, struct pcred *, struct proc *, int)); int killpg1 __P((struct proc *, int, int, int)); void sigexit_locked __P((struct proc *, int)); void setsigvec __P((struct proc *, int, struct sigaction *)); void exit1 __P((struct proc *, int, int *)); int signal_lock __P((struct proc *)); int signal_unlock __P((struct proc *)); void signal_setast __P((thread_act_t *)); void signal_clearast __P((thread_act_t *)); void psignal_lock __P((struct proc *, int, int, int)); #if SIGNAL_DEBUG void ram_printf __P((int)); int ram_debug=0; unsigned int rdebug_proc=0; void ram_printf(int x) { printf("x is %d",x); } #endif /* SIGNAL_DEBUG */ int signal_lock(struct proc *p) { int error = 0; #if SIGNAL_DEBUG #ifdef __ppc__ { int register sp, *fp, numsaved; __asm__ volatile("mr %0,r1" : "=r" (sp)); fp = (int *)*((int *)sp); for (numsaved = 0; numsaved < 3; numsaved++) { p->lockpc[numsaved] = fp[2]; if ((int)fp <= 0) break; fp = (int *)*fp; } } #endif /* __ppc__ */ #endif /* SIGNAL_DEBUG */ siglock_retry: error = lockmgr(&p->signal_lock, LK_EXCLUSIVE, 0, (struct proc *)0); if (error == EINTR) goto siglock_retry; return(error); } int signal_unlock(struct proc *p) { #if SIGNAL_DEBUG #ifdef __ppc__ { int register sp, *fp, numsaved; __asm__ volatile("mr %0,r1" : "=r" (sp)); fp = (int *)*((int *)sp); for (numsaved = 0; numsaved < 3; numsaved++) { p->unlockpc[numsaved] = fp[2]; if ((int)fp <= 0) break; fp = (int *)*fp; } } #endif /* __ppc__ */ #endif /* SIGNAL_DEBUG */ return(lockmgr(&p->signal_lock, LK_RELEASE, (simple_lock_t)0, (struct proc *)0)); } void signal_setast(sig_actthread) thread_act_t *sig_actthread; { thread_ast_set(sig_actthread, AST_BSD); if ((thread_act_t *)current_act() == sig_actthread) ast_on(AST_BSD); } void signal_clearast(sig_actthread) thread_act_t *sig_actthread; { thread_ast_clear(sig_actthread, AST_BSD); if ((thread_act_t *)current_act() == sig_actthread) ast_off(AST_BSD); } /* * Can process p, with pcred pc, send the signal signum to process q? */ int cansignal(p, pc, q, signum) struct proc *p; struct pcred *pc; struct proc *q; int signum; { if (pc->pc_ucred->cr_uid == 0) return (1); /* root can always signal */ if (signum == SIGCONT && q->p_session == p->p_session) return (1); /* SIGCONT in session */ /* * Using kill(), only certain signals can be sent to setugid * child processes */ if (q->p_flag & P_SUGID) { switch (signum) { case 0: case SIGKILL: case SIGINT: case SIGTERM: case SIGSTOP: case SIGTTIN: case SIGTTOU: case SIGTSTP: case SIGHUP: case SIGUSR1: case SIGUSR2: if (pc->p_ruid == q->p_cred->p_ruid || pc->pc_ucred->cr_uid == q->p_cred->p_ruid || pc->p_ruid == q->p_ucred->cr_uid || pc->pc_ucred->cr_uid == q->p_ucred->cr_uid) return (1); } return (0); } /* XXX * because the P_SUGID test exists, this has extra tests which * could be removed. */ if (pc->p_ruid == q->p_cred->p_ruid || pc->p_ruid == q->p_cred->p_svuid || pc->pc_ucred->cr_uid == q->p_cred->p_ruid || pc->pc_ucred->cr_uid == q->p_cred->p_svuid || pc->p_ruid == q->p_ucred->cr_uid || pc->pc_ucred->cr_uid == q->p_ucred->cr_uid) return (1); return (0); } struct sigaction_args { int signum; struct sigaction *nsa; struct sigaction *osa; }; /* ARGSUSED */ int sigaction(p, uap, retval) struct proc *p; register struct sigaction_args *uap; register_t *retval; { struct sigaction vec; register struct sigaction *sa; register struct sigacts *ps = p->p_sigacts; register int signum; int bit, error; signum = uap->signum; if (signum <= 0 || signum >= NSIG || signum == SIGKILL || signum == SIGSTOP) return (EINVAL); sa = &vec; if (uap->osa) { sa->sa_handler = ps->ps_sigact[signum]; sa->sa_mask = ps->ps_catchmask[signum]; bit = sigmask(signum); sa->sa_flags = 0; if ((ps->ps_sigonstack & bit) != 0) sa->sa_flags |= SA_ONSTACK; if ((ps->ps_sigintr & bit) == 0) sa->sa_flags |= SA_RESTART; if (p->p_flag & P_NOCLDSTOP) sa->sa_flags |= SA_NOCLDSTOP; if (error = copyout((caddr_t)sa, (caddr_t)uap->osa, sizeof (vec))) return (error); } if (uap->nsa) { if (error = copyin((caddr_t)uap->nsa, (caddr_t)sa, sizeof (vec))) return (error); setsigvec(p, signum, sa); } return (0); } static int reset_sigbits(thread_act_t th_act, int bit) { struct uthread *ut; ut = get_bsdthread_info(th_act); if (ut) { ut->uu_sig &= ~bit; } } int clear_sigbits (struct proc *p, int bit) { task_t task = p->task; p->p_siglist &= ~(bit); task_act_iterate_wth_args(task, reset_sigbits, bit); return(0); } void setsigvec(p, signum, sa) register struct proc *p; int signum; register struct sigaction *sa; { register struct sigacts *ps = p->p_sigacts; register int bit; bit = sigmask(signum); /* * Change setting atomically. */ ps->ps_sigact[signum] = sa->sa_handler; ps->ps_catchmask[signum] = sa->sa_mask &~ sigcantmask; if ((sa->sa_flags & SA_RESTART) == 0) ps->ps_sigintr |= bit; else ps->ps_sigintr &= ~bit; if (sa->sa_flags & SA_ONSTACK) ps->ps_sigonstack |= bit; else ps->ps_sigonstack &= ~bit; if (sa->sa_flags & SA_USERTRAMP) ps->ps_usertramp |= bit; else ps->ps_usertramp &= ~bit; if (signum == SIGCHLD) { if (sa->sa_flags & SA_NOCLDSTOP) p->p_flag |= P_NOCLDSTOP; else p->p_flag &= ~P_NOCLDSTOP; } /* * Set bit in p_sigignore for signals that are set to SIG_IGN, * and for signals set to SIG_DFL where the default is to ignore. * However, don't put SIGCONT in p_sigignore, * as we have to restart the process. */ if (sa->sa_handler == SIG_IGN || (sigprop[signum] & SA_IGNORE && sa->sa_handler == SIG_DFL)) { p->p_siglist &= ~bit; /* never to be seen again */ /* * If this is a thread signal, clean out the * threads as well. */ if (bit & threadmask) { register task_t task = p->task; task_act_iterate_wth_args(task, reset_sigbits, bit); } if (signum != SIGCONT) p->p_sigignore |= bit; /* easier in psignal */ p->p_sigcatch &= ~bit; } else { p->p_sigignore &= ~bit; if (sa->sa_handler == SIG_DFL) p->p_sigcatch &= ~bit; else p->p_sigcatch |= bit; } } /* * Initialize signal state for process 0; * set to ignore signals that are ignored by default. */ void siginit(p) struct proc *p; { register int i; for (i = 0; i < NSIG; i++) if (sigprop[i] & SA_IGNORE && i != SIGCONT) p->p_sigignore |= sigmask(i); } /* * Reset signals for an exec of the specified process. */ void execsigs(p) register struct proc *p; { register struct sigacts *ps = p->p_sigacts; register int nc, mask; /* * Reset caught signals. Held signals remain held * through p_sigmask (unless they were caught, * and are now ignored by default). */ while (p->p_sigcatch) { nc = ffs((long)p->p_sigcatch); mask = sigmask(nc); p->p_sigcatch &= ~mask; if (sigprop[nc] & SA_IGNORE) { if (nc != SIGCONT) p->p_sigignore |= mask; p->p_siglist &= ~mask; } ps->ps_sigact[nc] = SIG_DFL; } /* * Reset stack state to the user stack. * Clear set of signals caught on the signal stack. */ ps->ps_sigstk.ss_flags = SA_DISABLE; ps->ps_sigstk.ss_size = 0; ps->ps_sigstk.ss_sp = 0; ps->ps_flags = 0; } /* * Manipulate signal mask. * Note that we receive new mask, not pointer, * and return old mask as return value; * the library stub does the rest. */ struct sigprocmask_args { int how; sigset_t mask; }; int sigprocmask(p, uap, retval) register struct proc *p; struct sigprocmask_args *uap; register_t *retval; { int error = 0; *retval = p->p_sigmask; switch (uap->how) { case SIG_BLOCK: p->p_sigmask |= uap->mask &~ sigcantmask; break; case SIG_UNBLOCK: p->p_sigmask &= ~(uap->mask); signal_setast(current_act()); break; case SIG_SETMASK: p->p_sigmask = uap->mask &~ sigcantmask; signal_setast(current_act()); break; default: error = EINVAL; break; } return (error); } /* ARGSUSED */ int sigpending(p, uap, retval) struct proc *p; void *uap; register_t *retval; { *retval = p->p_siglist; return (0); } #if COMPAT_43 /* * Generalized interface signal handler, 4.3-compatible. */ struct osigvec_args { int signum; struct sigvec *nsv; struct sigvec *osv; }; /* ARGSUSED */ int osigvec(p, uap, retval) struct proc *p; register struct osigvec_args *uap; register_t *retval; { struct sigvec vec; register struct sigacts *ps = p->p_sigacts; register struct sigvec *sv; register int signum; int bit, error; signum = uap->signum; if (signum <= 0 || signum >= NSIG || signum == SIGKILL || signum == SIGSTOP) return (EINVAL); sv = &vec; if (uap->osv) { *(sig_t *)&sv->sv_handler = ps->ps_sigact[signum]; sv->sv_mask = ps->ps_catchmask[signum]; bit = sigmask(signum); sv->sv_flags = 0; if ((ps->ps_sigonstack & bit) != 0) sv->sv_flags |= SV_ONSTACK; if ((ps->ps_sigintr & bit) != 0) sv->sv_flags |= SV_INTERRUPT; if (p->p_flag & P_NOCLDSTOP) sv->sv_flags |= SA_NOCLDSTOP; if (error = copyout((caddr_t)sv, (caddr_t)uap->osv, sizeof (vec))) return (error); } if (uap->nsv) { if (error = copyin((caddr_t)uap->nsv, (caddr_t)sv, sizeof (vec))) return (error); sv->sv_flags ^= SA_RESTART; /* opposite of SV_INTERRUPT */ setsigvec(p, signum, (struct sigaction *)sv); } return (0); } struct osigblock_args { int mask; }; int osigblock(p, uap, retval) register struct proc *p; struct osigblock_args *uap; register_t *retval; { *retval = p->p_sigmask; p->p_sigmask |= uap->mask &~ sigcantmask; return (0); } struct osigsetmask_args { int mask; }; int osigsetmask(p, uap, retval) struct proc *p; struct osigsetmask_args *uap; register_t *retval; { *retval = p->p_sigmask; p->p_sigmask = uap->mask &~ sigcantmask; return (0); } #endif /* COMPAT_43 */ /* * Suspend process until signal, providing mask to be set * in the meantime. Note nonstandard calling convention: * libc stub passes mask, not pointer, to save a copyin. */ int sigcontinue(error) { unix_syscall_return(EINTR); } struct sigsuspend_args { int mask; }; /* ARGSUSED */ int sigsuspend(p, uap, retval) register struct proc *p; struct sigsuspend_args *uap; register_t *retval; { register struct sigacts *ps = p->p_sigacts; /* * When returning from sigpause, we want * the old mask to be restored after the * signal handler has finished. Thus, we * save it here and mark the sigacts structure * to indicate this. */ ps->ps_oldmask = p->p_sigmask; ps->ps_flags |= SAS_OLDMASK; p->p_sigmask = uap->mask &~ sigcantmask; (void) tsleep0((caddr_t) p, PPAUSE|PCATCH, "pause", 0, sigcontinue); /* always return EINTR rather than ERESTART... */ return (EINTR); } #if COMPAT_43 struct osigstack_args { struct sigstack *nss; struct sigstack *oss; }; /* ARGSUSED */ int osigstack(p, uap, retval) struct proc *p; register struct osigstack_args *uap; register_t *retval; { struct sigstack ss; struct sigacts *psp; int error = 0; psp = p->p_sigacts; ss.ss_sp = psp->ps_sigstk.ss_sp; ss.ss_onstack = psp->ps_sigstk.ss_flags & SA_ONSTACK; if (uap->oss && (error = copyout((caddr_t)&ss, (caddr_t)uap->oss, sizeof (struct sigstack)))) return (error); if (uap->nss && (error = copyin((caddr_t)uap->nss, (caddr_t)&ss, sizeof (ss))) == 0) { psp->ps_sigstk.ss_sp = ss.ss_sp; psp->ps_sigstk.ss_size = 0; psp->ps_sigstk.ss_flags |= ss.ss_onstack & SA_ONSTACK; psp->ps_flags |= SAS_ALTSTACK; } return (error); } #endif /* COMPAT_43 */ struct sigaltstack_args { struct sigaltstack *nss; struct sigaltstack *oss; }; /* ARGSUSED */ int sigaltstack(p, uap, retval) struct proc *p; register struct sigaltstack_args *uap; register_t *retval; { struct sigacts *psp; struct sigaltstack ss; int error; psp = p->p_sigacts; if ((psp->ps_flags & SAS_ALTSTACK) == 0) psp->ps_sigstk.ss_flags |= SA_DISABLE; if (uap->oss && (error = copyout((caddr_t)&psp->ps_sigstk, (caddr_t)uap->oss, sizeof (struct sigaltstack)))) return (error); if (uap->nss == 0) return (0); if (error = copyin((caddr_t)uap->nss, (caddr_t)&ss, sizeof (ss))) return (error); if (ss.ss_flags & SA_DISABLE) { if (psp->ps_sigstk.ss_flags & SA_ONSTACK) return (EINVAL); psp->ps_flags &= ~SAS_ALTSTACK; psp->ps_sigstk.ss_flags = ss.ss_flags; return (0); } if (ss.ss_size < MINSIGSTKSZ) return (ENOMEM); psp->ps_flags |= SAS_ALTSTACK; psp->ps_sigstk= ss; return (0); } struct kill_args { int pid; int signum; }; /* ARGSUSED */ int kill(cp, uap, retval) register struct proc *cp; register struct kill_args *uap; register_t *retval; { register struct proc *p; register struct pcred *pc = cp->p_cred; if ((u_int)uap->signum >= NSIG) return (EINVAL); if (uap->pid > 0) { /* kill single process */ if ((p = pfind(uap->pid)) == NULL) return (ESRCH); if (!cansignal(cp, pc, p, uap->signum)) return (EPERM); if (uap->signum) psignal(p, uap->signum); return (0); } switch (uap->pid) { case -1: /* broadcast signal */ return (killpg1(cp, uap->signum, 0, 1)); case 0: /* signal own process group */ return (killpg1(cp, uap->signum, 0, 0)); default: /* negative explicit process group */ return (killpg1(cp, uap->signum, -(uap->pid), 0)); } /* NOTREACHED */ } #if COMPAT_43 struct okillpg_args { int pgid; int signum; }; /* ARGSUSED */ int okillpg(p, uap, retval) struct proc *p; register struct okillpg_args *uap; register_t *retval; { if ((u_int)uap->signum >= NSIG) return (EINVAL); return (killpg1(p, uap->signum, uap->pgid, 0)); } #endif /* COMPAT_43 */ /* * Common code for kill process group/broadcast kill. * cp is calling process. */ int killpg1(cp, signum, pgid, all) register struct proc *cp; int signum, pgid, all; { register struct proc *p; register struct pcred *pc = cp->p_cred; struct pgrp *pgrp; int nfound = 0; if (all) { /* * broadcast */ for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { if (p->p_pid <= 1 || p->p_flag & P_SYSTEM || p == cp || !cansignal(cp, pc, p, signum)) continue; nfound++; if (signum) psignal(p, signum); } } else { if (pgid == 0) /* * zero pgid means send to my process group. */ pgrp = cp->p_pgrp; else { pgrp = pgfind(pgid); if (pgrp == NULL) return (ESRCH); } for (p = pgrp->pg_members.lh_first; p != 0; p = p->p_pglist.le_next) { if (p->p_pid <= 1 || p->p_flag & P_SYSTEM || p->p_stat == SZOMB || !cansignal(cp, pc, p, signum)) continue; nfound++; if (signum) psignal(p, signum); } } return (nfound ? 0 : ESRCH); } /* * Send a signal to a process group. */ void gsignal(pgid, signum) int pgid, signum; { struct pgrp *pgrp; if (pgid && (pgrp = pgfind(pgid))) pgsignal(pgrp, signum, 0); } /* * Send a signal to a process group. If checktty is 1, * limit to members which have a controlling terminal. */ void pgsignal(pgrp, signum, checkctty) struct pgrp *pgrp; int signum, checkctty; { register struct proc *p; if (pgrp) for (p = pgrp->pg_members.lh_first; p != 0; p = p->p_pglist.le_next) if (checkctty == 0 || p->p_flag & P_CONTROLT) psignal(p, signum); } /* * Send a signal caused by a trap to a specific thread. */ void threadsignal(sig_actthread, signum, code) register thread_act_t *sig_actthread; register int signum; u_long code; { register struct uthread *uth; register struct task * sig_task; register struct proc *p ; int mask; if ((u_int)signum >= NSIG || signum == 0) return; mask = sigmask(signum); if ((mask & threadmask) == 0) return; sig_task = get_threadtask(sig_actthread); p = (struct proc *)(get_bsdtask_info(sig_task)); uth = get_bsdthread_info(sig_actthread); if (uth && (uth->uu_flag & P_VFORK)) p = uth->uu_proc; if (!(p->p_flag & P_TRACED) && (p->p_sigignore & mask)) return; uth->uu_sig |= mask; uth->uu_code = code; /* mark on process as well */ p->p_siglist |= mask; signal_setast(sig_actthread); } void psignal_pend(p) register struct proc *p; { boolean_t funnel_state; register int sigbits, mask, signum; thread_funnel_set(kernel_flock, TRUE); if (p->p_sigpending == 0) return; signal_lock(p); for (;;) { sigbits = p->p_sigpending; if (sigbits == 0) goto out; signum = ffs((long)sigbits); mask = sigmask(signum); p->p_sigpending &= ~mask; psignal_lock(p, signum, 0, 0); } out: p->p_flag &= ~P_SIGTHR; signal_unlock(p); thread_funnel_set(kernel_flock, FALSE); } void psignal(p, signum) register struct proc *p; register int signum; { psignal_lock(p, signum, 1, 1); } void psignal_vfork(p, new_task, thr_act, signum) register struct proc *p; task_t new_task; thread_act_t thr_act; register int signum; { int withlock = 1; int pend = 0; register int s, prop; register sig_t action; int mask; kern_return_t kret; if ((u_int)signum >= NSIG || signum == 0) panic("psignal signal number"); mask = sigmask(signum); prop = sigprop[signum]; #if SIGNAL_DEBUG if(rdebug_proc && (p == rdebug_proc)) { ram_printf(3); } #endif /* SIGNAL_DEBUG */ if ((new_task == TASK_NULL) || (thr_act == (thread_act_t)NULL) || is_kerneltask(new_task)) return; signal_lock(p); /* * proc is traced, always give parent a chance. */ action = SIG_DFL; if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && (p->p_flag & P_TRACED) == 0) p->p_nice = NZERO; if (prop & SA_CONT) p->p_siglist &= ~stopsigmask; if (prop & SA_STOP) { /* * If sending a tty stop signal to a member of an orphaned * process group, discard the signal here if the action * is default; don't stop the process below if sleeping, * and don't clear any pending SIGCONT. */ if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 && action == SIG_DFL) goto psigout; p->p_siglist &= ~contsigmask; } p->p_siglist |= mask; /* Deliver signal to the activation passed in */ thread_ast_set(thr_act, AST_BSD); /* * SIGKILL priority twiddling moved here from above because * it needs sig_thread. Could merge it into large switch * below if we didn't care about priority for tracing * as SIGKILL's action is always SIG_DFL. */ if ((signum == SIGKILL) && (p->p_nice > NZERO)) { p->p_nice = NZERO; #if XXX /* * we need to make changes here to get nice to work * reset priority to BASEPRI_USER */ #endif } /* * This Process is traced - wake it up (if not already * stopped) so that it can discover the signal in * issig() and stop for the parent. */ if (p->p_flag & P_TRACED) { if (p->p_stat != SSTOP) goto run; else goto psigout; } run: /* * If we're being traced (possibly because someone attached us * while we were stopped), check for a signal from the debugger. */ if (p->p_stat == SSTOP) { if ((p->p_flag & P_TRACED) != 0 && p->p_xstat != 0) p->p_siglist |= sigmask(p->p_xstat); } /* * setrunnable(p) in BSD */ p->p_stat = SRUN; psigout: signal_unlock(p); } /* * Send the signal to the process. If the signal has an action, the action * is usually performed by the target process rather than the caller; we add * the signal to the set of pending signals for the process. * * Exceptions: * o When a stop signal is sent to a sleeping process that takes the * default action, the process is stopped without awakening it. * o SIGCONT restarts stopped processes (or puts them back to sleep) * regardless of the signal action (eg, blocked or ignored). * * Other ignored signals are discarded immediately. */ void psignal_lock(p, signum, withlock, pend) register struct proc *p; register int signum; register int withlock; register int pend; { register int s, prop; register sig_t action; thread_act_t sig_thread_act; thread_t sig_thread; register task_t sig_task; register thread_t cur_thread; thread_act_t *cur_act; int mask; kern_return_t kret; if ((u_int)signum >= NSIG || signum == 0) panic("psignal signal number"); mask = sigmask(signum); prop = sigprop[signum]; #if SIGNAL_DEBUG if(rdebug_proc && (p == rdebug_proc)) { ram_printf(3); } #endif /* SIGNAL_DEBUG */ /* * We will need the task pointer later. Grab it now to * check for a zombie process. Also don't send signals * to kernel internal tasks. */ if (((sig_task = p->task) == TASK_NULL) || is_kerneltask(sig_task)) return; /* * do not send signals to the process that has the thread * doing a reboot(). Not doing so will mark that thread aborted * and can cause IO failures wich will cause data loss. */ if (ISSET(p->p_flag, P_REBOOT)) return; /* * if the traced process is blocked waiting for * gdb then do not block the caller just pend * the signal. Setup a callout to process the * pended signal if not alreadu set */ if (pend && (p->p_flag & P_TRACED) && p->sigwait) { p->p_sigpending |= mask; if (!(p->p_flag & P_SIGTHR)) { p->p_flag |= P_SIGTHR; thread_call_func((thread_call_func_t)psignal_pend, p, FALSE); } return; } if (withlock) signal_lock(p); /* * If proc is traced, always give parent a chance. */ if (p->p_flag & P_TRACED) action = SIG_DFL; else { /* * If the signal is being ignored, * then we forget about it immediately. * (Note: we don't set SIGCONT in p_sigignore, * and if it is set to SIG_IGN, * action will be SIG_DFL here.) */ if (p->p_sigignore & mask) goto psigout; if (p->p_sigmask & mask) action = SIG_HOLD; else if (p->p_sigcatch & mask) action = SIG_CATCH; else action = SIG_DFL; } if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && (p->p_flag & P_TRACED) == 0) p->p_nice = NZERO; if (prop & SA_CONT) p->p_siglist &= ~stopsigmask; if (prop & SA_STOP) { /* * If sending a tty stop signal to a member of an orphaned * process group, discard the signal here if the action * is default; don't stop the process below if sleeping, * and don't clear any pending SIGCONT. */ if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 && action == SIG_DFL) goto psigout; p->p_siglist &= ~contsigmask; } p->p_siglist |= mask; /* * Defer further processing for signals which are held, * except that stopped processes must be continued by SIGCONT. */ if (action == SIG_HOLD && ((prop & SA_CONT) == 0 || p->p_stat != SSTOP)) goto psigout; /* * Deliver the signal to the first thread in the task. This * allows single threaded applications which use signals to * be able to be linked with multithreaded libraries. We have * an implicit reference to the current_thread, but need * an explicit one otherwise. The thread reference keeps * the corresponding task data structures around too. This * reference is released by thread_deallocate. */ cur_thread = current_thread(); /* this is a shuttle */ cur_act = current_act(); if ((p->p_flag & P_INVFORK) && p->p_vforkact) { sig_thread_act = p->p_vforkact; kret = check_actforsig(sig_task, sig_thread_act, &sig_thread, 1); if (kret == KERN_SUCCESS) { goto psig_foundthread; } } /* If successful return with ast set */ kret = (kern_return_t)get_signalact(sig_task, &sig_thread_act, &sig_thread, 1); if ((kret != KERN_SUCCESS) || (sig_thread_act == THREAD_NULL)) { /* XXXX FIXME /* if it is sigkill, may be we should * inject a thread to terminate */ #if DIAGNOSTIC printf("WARNING: no activation in psignal\n"); #endif #if SIGNAL_DEBUG ram_printf(1); #endif /* SIGNAL_DEBUG */ goto psigout; } psig_foundthread: if (sig_thread == THREAD_NULL) { #if DIAGNOSTIC printf("WARNING: valid act; but no shutte in psignal\n"); #endif #if 0 /* FIXME : NO VALID SHUTTLE */ goto psigout; #endif } /* * SIGKILL priority twiddling moved here from above because * it needs sig_thread. Could merge it into large switch * below if we didn't care about priority for tracing * as SIGKILL's action is always SIG_DFL. */ if ((signum == SIGKILL) && (p->p_nice > NZERO)) { p->p_nice = NZERO; #if XXX /* * we need to make changes here to get nice to work * reset priority to BASEPRI_USER */ #endif } /* * Process is traced - wake it up (if not already * stopped) so that it can discover the signal in * issig() and stop for the parent. */ if (p->p_flag & P_TRACED) { if (p->p_stat != SSTOP) goto run; else goto psigout; } if (action != SIG_DFL) { /* * User wants to catch the signal. * Wake up the thread, but don't un-suspend it * (except for SIGCONT). */ if (prop & SA_CONT) (void) task_resume(sig_task); goto run; } else { /* Default action - varies */ if (mask & stopsigmask) { /* * These are the signals which by default * stop a process. * * Don't clog system with children of init * stopped from the keyboard. */ if (!(prop & SA_STOP) && p->p_pptr == initproc) { psignal_lock(p, SIGKILL, 0, 1); p->p_siglist &= ~mask; goto psigout; } /* * Stop the task. */ if (!is_thread_running(sig_thread)) { /* Thread is not running * If task hasn't already been stopped by * a signal, stop it. */ p->p_siglist &= ~mask; if (get_task_userstop(sig_task) == 0) { /* * p_cursig must not be set, because * it will be psig()'d if it is not * zero, and the signal is being * handled here. But save the signal * in p_stopsig so WUNTRACED * option to wait can find it. */ p->p_xstat = signum; if ((p->p_pptr->p_flag & P_NOCLDSTOP) == 0) psignal(p->p_pptr, SIGCHLD); stop(p); } #if 0 /* unconditional check is bad */ signal_clearast(sig_thread_act); #endif goto psigout; } else { if (p->p_stat != SZOMB) signal_setast(cur_act); goto psigout; } } switch (signum) { /* * Signals ignored by default have been dealt * with already, since their bits are on in * p_sigignore. */ case SIGKILL: /* * Kill signal always sets process running and * unsuspends it. */ /* * Process will be running after 'run' */ p->p_stat = SRUN; thread_abort(sig_thread_act); goto psigout; case SIGCONT: /* * Let the process run. If it's sleeping on an * event, it remains so. */ if (p->p_flag & P_TTYSLEEP) { p->p_flag &= ~P_TTYSLEEP; wakeup(&p->p_siglist); } else { (void) task_resume(sig_task); } p->p_siglist &= ~mask; p->p_stat = SRUN; #if 0 /* do not clear AST as tcsh is sendig SIGTERM followed by * SIGCONT and the ast was getting cleared unconditinally * This is not right. */ signal_clearast(sig_thread_act); #endif goto psigout; default: /* * All other signals wake up the process, but don't * resume it. */ goto run; } } /*NOTREACHED*/ run: /* * If we're being traced (possibly because someone attached us * while we were stopped), check for a signal from the debugger. */ if (p->p_stat == SSTOP) { if ((p->p_flag & P_TRACED) != 0 && p->p_xstat != 0) p->p_siglist |= sigmask(p->p_xstat); } /* * setrunnable(p) in BSD */ p->p_stat = SRUN; /* * Wake up the thread if it is interruptible. */ thread_abort_safely(sig_thread_act); psigout: if (withlock) signal_unlock(p); } __inline__ void sig_lock_to_exit( struct proc *p) { thread_t self = current_thread(); p->exit_thread = self; (void) task_suspend(p->task); } __inline__ int sig_try_locked( struct proc *p) { thread_t self = current_thread(); while (p->sigwait || p->exit_thread) { if (p->exit_thread) { if (p->exit_thread != self) { /* * Already exiting - no signals. */ thread_abort(current_act()); } return(0); } if(assert_wait_possible()) { assert_wait((caddr_t)&p->sigwait_thread, (THREAD_INTERRUPTIBLE)); } signal_unlock(p); thread_block(0); signal_lock(p); if (thread_should_abort(self)) { /* * Terminate request - clean up. */ return -1; } } return 1; } /* * If the current process has received a signal (should be caught or cause * termination, should interrupt current syscall), return the signal number. * Stop signals with default action are processed immediately, then cleared; * they aren't returned. This is checked after each entry to the system for * a syscall or trap (though this can usually be done without calling issignal * by checking the pending signal masks in the CURSIG macro.) The normal call * sequence is * * while (signum = CURSIG(curproc)) * postsig(signum); */ int issignal(p) register struct proc *p; { register int signum, mask, prop, sigbits; task_t task = p->task; thread_t cur_thread; thread_act_t cur_act; int s; struct uthread * ut; kern_return_t kret; cur_thread = current_thread(); cur_act = current_act(); signal_lock(p); /* * Try to grab the signal lock. */ if (sig_try_locked(p) <= 0) { signal_unlock(p); return (0); } ut = get_bsdthread_info(cur_act); for(;;) { sigbits = (ut->uu_sig |p->p_siglist) & ~p->p_sigmask; if (p->p_flag & P_PPWAIT) sigbits &= ~stopsigmask; if (sigbits == 0) { /* no signal to send */ signal_unlock(p); return (0); } signum = ffs((long)sigbits); mask = sigmask(signum); prop = sigprop[signum]; if (mask & threadmask) { /* we can take this signal */ ut->uu_sig &= ~mask; } /* * We should see pending but ignored signals * only if P_TRACED was on when they were posted. */ if (mask & p->p_sigignore && (p->p_flag & P_TRACED) == 0) { p->p_siglist &= ~mask; /* take the signal! */ continue; } if (p->p_flag & P_TRACED && (p->p_flag & P_PPWAIT) == 0) { register int hold; register task_t task; /* * If traced, always stop, and stay * stopped until released by the debugger. */ /* ptrace debugging */ p->p_xstat = signum; psignal(p->p_pptr, SIGCHLD); /* * XXX Have to really stop for debuggers; * XXX stop() doesn't do the right thing. * XXX Inline the task_suspend because we * XXX have to diddle Unix state in the * XXX middle of it. */ task = p->task; task_hold(task); p->sigwait = TRUE; p->sigwait_thread = cur_act; p->p_stat = SSTOP; p->p_flag &= ~P_WAITED; p->p_siglist &= ~mask; /* clear the old signal */ wakeup((caddr_t)p->p_pptr); assert_wait((caddr_t)&p->sigwait, (THREAD_INTERRUPTIBLE)); thread_block(0); p->sigwait = FALSE; p->sigwait_thread = NULL; wakeup((caddr_t)&p->sigwait_thread); /* * This code is to detect when gdb is killed * even as the traced program is attached. * pgsignal would get the SIGKILL to traced program * That's what we are trying to see (I hope) */ if (p->p_siglist & sigmask(SIGKILL)) { /* * Wait event may still be outstanding; * clear it, since sig_lock_to_exit will * wait. */ clear_wait(current_thread(), THREAD_INTERRUPTED); sig_lock_to_exit(p); /* * Since this thread will be resumed * to allow the current syscall to * be completed, must save u_qsave * before calling exit(). (Since exit() * calls closef() which can trash u_qsave.) */ signal_unlock(p); exit1(p,signum, (int *)NULL); return(0); } /* * We may have to quit */ if (thread_should_abort(current_thread())) { signal_unlock(p); return(0); } /* * If parent wants us to take the signal, * then it will leave it in p->p_xstat; * otherwise we just look for signals again. */ signum = p->p_xstat; if (signum == 0) continue; /* * Put the new signal into p_siglist. If the * signal is being masked, look for other signals. */ mask = sigmask(signum); if (mask & threadmask) ut->uu_sig |= mask; else p->p_siglist |= mask; if (p->p_sigmask & mask) continue; } /* * Decide whether the signal should be returned. * Return the signal's number, or fall through * to clear it from the pending mask. */ switch ((long)p->p_sigacts->ps_sigact[signum]) { case (long)SIG_DFL: /* * Don't take default actions on system processes. */ if (p->p_pptr->p_pid == 0) { #if DIAGNOSTIC /* * Are you sure you want to ignore SIGSEGV * in init? XXX */ printf("Process (pid %d) got signal %d\n", p->p_pid, signum); #endif break; /* == ignore */ } /* * If there is a pending stop signal to process * with default action, stop here, * then clear the signal. However, * if process is member of an orphaned * process group, ignore tty stop signals. */ if (prop & SA_STOP) { if (p->p_flag & P_TRACED || (p->p_pgrp->pg_jobc == 0 && prop & SA_TTYSTOP)) break; /* == ignore */ p->p_xstat = signum; stop(p); if ((p->p_pptr->p_flag & P_NOCLDSTOP) == 0) psignal(p->p_pptr, SIGCHLD); thread_block(0); /* * We may have to quit */ if (thread_should_abort(current_thread())) { signal_unlock(p); return(0); } break; } else if (prop & SA_IGNORE) { /* * Except for SIGCONT, shouldn't get here. * Default action is to ignore; drop it. */ break; /* == ignore */ } else { p->p_siglist &= ~mask; /* take the signal! */ p->p_sigpending &= ~mask; /* take the pending signal */ signal_unlock(p); return (signum); } /*NOTREACHED*/ case (long)SIG_IGN: /* * Masking above should prevent us ever trying * to take action on an ignored signal other * than SIGCONT, unless process is traced. */ if ((prop & SA_CONT) == 0 && (p->p_flag & P_TRACED) == 0) printf("issignal\n"); break; /* == ignore */ default: /* * This signal has an action, let * postsig() process it. */ p->p_siglist &= ~mask; /* take the signal! */ p->p_sigpending &= ~mask; /* take the pending signal */ signal_unlock(p); return (signum); } p->p_siglist &= ~mask; /* take the signal! */ p->p_sigpending &= ~mask; /* take the pending signal */ } /* NOTREACHED */ } /* called from _sleep */ int CURSIG(p) register struct proc *p; { register int signum, mask, prop, sigbits; task_t task = p->task; thread_t cur_thread; thread_act_t cur_act; int s; struct uthread * ut; int retnum = 0; if (p->p_siglist == 0) return (0); if (((p->p_siglist & ~p->p_sigmask) == 0) && ((p->p_flag & P_TRACED) == 0)) return (0); cur_thread = current_thread(); cur_act = current_act(); ut = get_bsdthread_info(cur_act); sigbits = (ut->uu_sig | p->p_siglist) & ~p->p_sigmask; for(;;) { if (p->p_flag & P_PPWAIT) sigbits &= ~stopsigmask; if (sigbits == 0) { /* no signal to send */ return (retnum); } signum = ffs((long)sigbits); mask = sigmask(signum); prop = sigprop[signum]; /* * We should see pending but ignored signals * only if P_TRACED was on when they were posted. */ if (mask & p->p_sigignore && (p->p_flag & P_TRACED) == 0) { continue; } if (p->p_flag & P_TRACED && (p->p_flag & P_PPWAIT) == 0) { /* * Put the new signal into p_siglist. If the * signal is being masked, look for other signals. */ mask = sigmask(signum); if (p->p_sigmask & mask) continue; return(signum); } /* * Decide whether the signal should be returned. * Return the signal's number, or fall through * to clear it from the pending mask. */ switch ((long)p->p_sigacts->ps_sigact[signum]) { case (long)SIG_DFL: /* * Don't take default actions on system processes. */ if (p->p_pptr->p_pid == 0) { #if DIAGNOSTIC /* * Are you sure you want to ignore SIGSEGV * in init? XXX */ printf("Process (pid %d) got signal %d\n", p->p_pid, signum); #endif break; /* == ignore */ } /* * If there is a pending stop signal to process * with default action, stop here, * then clear the signal. However, * if process is member of an orphaned * process group, ignore tty stop signals. */ if (prop & SA_STOP) { if (p->p_flag & P_TRACED || (p->p_pgrp->pg_jobc == 0 && prop & SA_TTYSTOP)) break; /* == ignore */ retnum = signum; break; } else if (prop & SA_IGNORE) { /* * Except for SIGCONT, shouldn't get here. * Default action is to ignore; drop it. */ break; /* == ignore */ } else { return (signum); } /*NOTREACHED*/ case (long)SIG_IGN: /* * Masking above should prevent us ever trying * to take action on an ignored signal other * than SIGCONT, unless process is traced. */ if ((prop & SA_CONT) == 0 && (p->p_flag & P_TRACED) == 0) printf("issignal\n"); break; /* == ignore */ default: /* * This signal has an action, let * postsig() process it. */ return (signum); } sigbits &= ~mask; /* take the signal! */ } /* NOTREACHED */ } /* * Put the argument process into the stopped state and notify the parent * via wakeup. Signals are handled elsewhere. The process must not be * on the run queue. */ void stop(p) register struct proc *p; { p->p_stat = SSTOP; p->p_flag &= ~P_WAITED; wakeup((caddr_t)p->p_pptr); (void) task_suspend(p->task); /*XXX*/ } /* * Take the action for the specified signal * from the current set of pending signals. */ void postsig(signum) register int signum; { register struct proc *p = current_proc(); register struct sigacts *ps = p->p_sigacts; register sig_t action; u_long code; int mask, returnmask; #if DIAGNOSTIC if (signum == 0) panic("postsig"); /* * This must be called on master cpu */ if (cpu_number() != master_cpu) panic("psig not on master"); #endif signal_lock(p); /* * Try to grab the signal lock. */ if (sig_try_locked(p) <= 0) { signal_unlock(p); return; } mask = sigmask(signum); p->p_siglist &= ~mask; action = ps->ps_sigact[signum]; #if KTRACE if (KTRPOINT(p, KTR_PSIG)) ktrpsig(p->p_tracep, signum, action, ps->ps_flags & SAS_OLDMASK ? ps->ps_oldmask : p->p_sigmask, 0); #endif if (action == SIG_DFL) { /* * Default action, where the default is to kill * the process. (Other cases were ignored above.) */ /* called with signal_lock() held */ sigexit_locked(p, signum); return; /* NOTREACHED */ } else { /* * If we get here, the signal must be caught. */ #if DIAGNOSTIC if (action == SIG_IGN || (p->p_sigmask & mask)) log(LOG_WARNING, "postsig: processing masked or ignored signal\n"); #endif /* * Set the new mask value and also defer further * occurences of this signal. * * Special case: user has done a sigpause. Here the * current mask is not of interest, but rather the * mask from before the sigpause is what we want * restored after the signal processing is completed. */ if (ps->ps_flags & SAS_OLDMASK) { returnmask = ps->ps_oldmask; ps->ps_flags &= ~SAS_OLDMASK; } else returnmask = p->p_sigmask; p->p_sigmask |= ps->ps_catchmask[signum] | mask; if (ps->ps_sig != signum) { code = 0; } else { code = ps->ps_code; ps->ps_code = 0; } p->p_stats->p_ru.ru_nsignals++; sendsig(p, action, signum, returnmask, code); } signal_unlock(p); } /* * Force the current process to exit with the specified signal, dumping core * if appropriate. We bypass the normal tests for masked and caught signals, * allowing unrecoverable failures to terminate the process without changing * signal state. Mark the accounting record with the signal termination. * If dumping core, save the signal number for the debugger. Calls exit and * does not return. */ /* called with signal lock */ void sigexit_locked(p, signum) register struct proc *p; int signum; { sig_lock_to_exit(p); p->p_acflag |= AXSIG; if (sigprop[signum] & SA_CORE) { p->p_sigacts->ps_sig = signum; if (coredump(p) == 0) signum |= WCOREFLAG; } signal_unlock(p); exit1(p, W_EXITCODE(0, signum), (int *)NULL); /* NOTREACHED */ } void bsd_ast(thread_act_t thr_act) { struct proc *p = current_proc(); struct uthread *ut = get_bsdthread_info(thr_act); int signum; unsigned int pc; boolean_t funnel_state; if (p == NULL) return; funnel_state = thread_funnel_set(kernel_flock, TRUE); if ((p->p_flag & P_OWEUPC) && (p->p_flag & P_PROFIL)) { pc = get_useraddr(); addupc_task(p, pc, 1); p->p_flag &= ~P_OWEUPC; } if (CHECK_SIGNALS(p, current_thread(), ut)) { while (signum = issignal(p)) postsig(signum); } ast_off(AST_BSD); (void) thread_funnel_set(kernel_flock, FALSE); } /* * Follwing routines are called using callout from bsd_hardclock * so that psignals are called in a thread context and are funneled */ void psignal_vtalarm(struct proc *p) { boolean_t funnel_state; if (p == NULL) return; funnel_state = thread_funnel_set(kernel_flock, TRUE); psignal_lock(p, SIGVTALRM, 1, 1); (void) thread_funnel_set(kernel_flock, FALSE); } void psignal_xcpu(struct proc *p) { boolean_t funnel_state; if (p == NULL) return; funnel_state = thread_funnel_set(kernel_flock, TRUE); psignal_lock(p, SIGXCPU, 1, 1); (void) thread_funnel_set(kernel_flock, FALSE); } void psignal_sigprof(struct proc *p) { boolean_t funnel_state; if (p == NULL) return; funnel_state = thread_funnel_set(kernel_flock, TRUE); psignal_lock(p, SIGPROF, 1, 1); (void) thread_funnel_set(kernel_flock, FALSE); } /* ptrace set runnalbe */ void pt_setrunnable(struct proc *p) { task_t task; task = p->task; if (p->p_flag & P_TRACED) { p->p_stat = SRUN; if (p->sigwait) { wakeup((caddr_t)&(p->sigwait)); task_release(task); } } }