/* $NetBSD: kern_sig.c,v 1.218 2006/03/12 18:36:58 christos Exp $ */ /* * 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. 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 8.14 (Berkeley) 5/14/95 */ #include __KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.218 2006/03/12 18:36:58 christos Exp $"); #include "opt_ktrace.h" #include "opt_compat_sunos.h" #include "opt_compat_netbsd.h" #include "opt_compat_netbsd32.h" #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 #include #include #include #include #include #include #include #include /* for coredump */ #include #include static int build_corename(struct proc *, char *, const char *, size_t); static void ksiginfo_exithook(struct proc *, void *); static void ksiginfo_put(struct proc *, const ksiginfo_t *); static ksiginfo_t *ksiginfo_get(struct proc *, int); static void kpsignal2(struct proc *, const ksiginfo_t *, int); sigset_t contsigmask, stopsigmask, sigcantmask; struct pool sigacts_pool; /* memory pool for sigacts structures */ /* * struct sigacts memory pool allocator. */ static void * sigacts_poolpage_alloc(struct pool *pp, int flags) { return (void *)uvm_km_alloc(kernel_map, (PAGE_SIZE)*2, (PAGE_SIZE)*2, ((flags & PR_WAITOK) ? 0 : UVM_KMF_NOWAIT | UVM_KMF_TRYLOCK) | UVM_KMF_WIRED); } static void sigacts_poolpage_free(struct pool *pp, void *v) { uvm_km_free(kernel_map, (vaddr_t)v, (PAGE_SIZE)*2, UVM_KMF_WIRED); } static struct pool_allocator sigactspool_allocator = { sigacts_poolpage_alloc, sigacts_poolpage_free, }; POOL_INIT(siginfo_pool, sizeof(siginfo_t), 0, 0, 0, "siginfo", &pool_allocator_nointr); POOL_INIT(ksiginfo_pool, sizeof(ksiginfo_t), 0, 0, 0, "ksiginfo", NULL); /* * Can process p, with pcred pc, send the signal signum to process q? */ #define CANSIGNAL(p, pc, q, signum) \ ((pc)->pc_ucred->cr_uid == 0 || \ (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 || \ ((signum) == SIGCONT && (q)->p_session == (p)->p_session)) /* * Remove and return the first ksiginfo element that matches our requested * signal, or return NULL if one not found. */ static ksiginfo_t * ksiginfo_get(struct proc *p, int signo) { ksiginfo_t *ksi; int s; s = splsoftclock(); simple_lock(&p->p_sigctx.ps_silock); CIRCLEQ_FOREACH(ksi, &p->p_sigctx.ps_siginfo, ksi_list) { if (ksi->ksi_signo == signo) { CIRCLEQ_REMOVE(&p->p_sigctx.ps_siginfo, ksi, ksi_list); goto out; } } ksi = NULL; out: simple_unlock(&p->p_sigctx.ps_silock); splx(s); return ksi; } /* * Append a new ksiginfo element to the list of pending ksiginfo's, if * we need to (SA_SIGINFO was requested). We replace non RT signals if * they already existed in the queue and we add new entries for RT signals, * or for non RT signals with non-existing entries. */ static void ksiginfo_put(struct proc *p, const ksiginfo_t *ksi) { ksiginfo_t *kp; struct sigaction *sa = &SIGACTION_PS(p->p_sigacts, ksi->ksi_signo); int s; if ((sa->sa_flags & SA_SIGINFO) == 0) return; /* * If there's no info, don't save it. */ if (KSI_EMPTY_P(ksi)) return; s = splsoftclock(); simple_lock(&p->p_sigctx.ps_silock); #ifdef notyet /* XXX: QUEUING */ if (ksi->ksi_signo < SIGRTMIN) #endif { CIRCLEQ_FOREACH(kp, &p->p_sigctx.ps_siginfo, ksi_list) { if (kp->ksi_signo == ksi->ksi_signo) { KSI_COPY(ksi, kp); goto out; } } } kp = pool_get(&ksiginfo_pool, PR_NOWAIT); if (kp == NULL) { #ifdef DIAGNOSTIC printf("Out of memory allocating siginfo for pid %d\n", p->p_pid); #endif goto out; } *kp = *ksi; CIRCLEQ_INSERT_TAIL(&p->p_sigctx.ps_siginfo, kp, ksi_list); out: simple_unlock(&p->p_sigctx.ps_silock); splx(s); } /* * free all pending ksiginfo on exit */ static void ksiginfo_exithook(struct proc *p, void *v) { int s; s = splsoftclock(); simple_lock(&p->p_sigctx.ps_silock); while (!CIRCLEQ_EMPTY(&p->p_sigctx.ps_siginfo)) { ksiginfo_t *ksi = CIRCLEQ_FIRST(&p->p_sigctx.ps_siginfo); CIRCLEQ_REMOVE(&p->p_sigctx.ps_siginfo, ksi, ksi_list); pool_put(&ksiginfo_pool, ksi); } simple_unlock(&p->p_sigctx.ps_silock); splx(s); } /* * Initialize signal-related data structures. */ void signal_init(void) { sigactspool_allocator.pa_pagesz = (PAGE_SIZE)*2; pool_init(&sigacts_pool, sizeof(struct sigacts), 0, 0, 0, "sigapl", sizeof(struct sigacts) > PAGE_SIZE ? &sigactspool_allocator : &pool_allocator_nointr); exithook_establish(ksiginfo_exithook, NULL); exechook_establish(ksiginfo_exithook, NULL); } /* * Create an initial sigctx structure, using the same signal state * as p. If 'share' is set, share the sigctx_proc part, otherwise just * copy it from parent. */ void sigactsinit(struct proc *np, struct proc *pp, int share) { struct sigacts *ps; if (share) { np->p_sigacts = pp->p_sigacts; pp->p_sigacts->sa_refcnt++; } else { ps = pool_get(&sigacts_pool, PR_WAITOK); if (pp) memcpy(ps, pp->p_sigacts, sizeof(struct sigacts)); else memset(ps, '\0', sizeof(struct sigacts)); ps->sa_refcnt = 1; np->p_sigacts = ps; } } /* * Make this process not share its sigctx, maintaining all * signal state. */ void sigactsunshare(struct proc *p) { struct sigacts *oldps; if (p->p_sigacts->sa_refcnt == 1) return; oldps = p->p_sigacts; sigactsinit(p, NULL, 0); if (--oldps->sa_refcnt == 0) pool_put(&sigacts_pool, oldps); } /* * Release a sigctx structure. */ void sigactsfree(struct sigacts *ps) { if (--ps->sa_refcnt > 0) return; pool_put(&sigacts_pool, ps); } int sigaction1(struct proc *p, int signum, const struct sigaction *nsa, struct sigaction *osa, const void *tramp, int vers) { struct sigacts *ps; int prop; ps = p->p_sigacts; if (signum <= 0 || signum >= NSIG) return (EINVAL); /* * Trampoline ABI version 0 is reserved for the legacy * kernel-provided on-stack trampoline. Conversely, if we are * using a non-0 ABI version, we must have a trampoline. Only * validate the vers if a new sigaction was supplied. Emulations * use legacy kernel trampolines with version 0, alternatively * check for that too. */ if ((vers != 0 && tramp == NULL) || #ifdef SIGTRAMP_VALID (nsa != NULL && ((vers == 0) ? (p->p_emul->e_sigcode == NULL) : !SIGTRAMP_VALID(vers))) || #endif (vers == 0 && tramp != NULL)) return (EINVAL); if (osa) *osa = SIGACTION_PS(ps, signum); if (nsa) { if (nsa->sa_flags & ~SA_ALLBITS) return (EINVAL); prop = sigprop[signum]; if (prop & SA_CANTMASK) return (EINVAL); (void) splsched(); /* XXXSMP */ SIGACTION_PS(ps, signum) = *nsa; ps->sa_sigdesc[signum].sd_tramp = tramp; ps->sa_sigdesc[signum].sd_vers = vers; sigminusset(&sigcantmask, &SIGACTION_PS(ps, signum).sa_mask); if ((prop & SA_NORESET) != 0) SIGACTION_PS(ps, signum).sa_flags &= ~SA_RESETHAND; if (signum == SIGCHLD) { if (nsa->sa_flags & SA_NOCLDSTOP) p->p_flag |= P_NOCLDSTOP; else p->p_flag &= ~P_NOCLDSTOP; if (nsa->sa_flags & SA_NOCLDWAIT) { /* * Paranoia: since SA_NOCLDWAIT is implemented * by reparenting the dying child to PID 1 (and * trust it to reap the zombie), PID 1 itself * is forbidden to set SA_NOCLDWAIT. */ if (p->p_pid == 1) p->p_flag &= ~P_NOCLDWAIT; else p->p_flag |= P_NOCLDWAIT; } else p->p_flag &= ~P_NOCLDWAIT; if (nsa->sa_handler == SIG_IGN) { /* * Paranoia: same as above. */ if (p->p_pid == 1) p->p_flag &= ~P_CLDSIGIGN; else p->p_flag |= P_CLDSIGIGN; } else p->p_flag &= ~P_CLDSIGIGN; } if ((nsa->sa_flags & SA_NODEFER) == 0) sigaddset(&SIGACTION_PS(ps, signum).sa_mask, signum); else sigdelset(&SIGACTION_PS(ps, signum).sa_mask, signum); /* * Set bit in p_sigctx.ps_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_sigctx.ps_sigignore, as we have to restart the process. */ if (nsa->sa_handler == SIG_IGN || (nsa->sa_handler == SIG_DFL && (prop & SA_IGNORE) != 0)) { /* never to be seen again */ sigdelset(&p->p_sigctx.ps_siglist, signum); if (signum != SIGCONT) { /* easier in psignal */ sigaddset(&p->p_sigctx.ps_sigignore, signum); } sigdelset(&p->p_sigctx.ps_sigcatch, signum); } else { sigdelset(&p->p_sigctx.ps_sigignore, signum); if (nsa->sa_handler == SIG_DFL) sigdelset(&p->p_sigctx.ps_sigcatch, signum); else sigaddset(&p->p_sigctx.ps_sigcatch, signum); } (void) spl0(); } return (0); } #ifdef COMPAT_16 /* ARGSUSED */ int compat_16_sys___sigaction14(struct lwp *l, void *v, register_t *retval) { struct compat_16_sys___sigaction14_args /* { syscallarg(int) signum; syscallarg(const struct sigaction *) nsa; syscallarg(struct sigaction *) osa; } */ *uap = v; struct proc *p; struct sigaction nsa, osa; int error; if (SCARG(uap, nsa)) { error = copyin(SCARG(uap, nsa), &nsa, sizeof(nsa)); if (error) return (error); } p = l->l_proc; error = sigaction1(p, SCARG(uap, signum), SCARG(uap, nsa) ? &nsa : 0, SCARG(uap, osa) ? &osa : 0, NULL, 0); if (error) return (error); if (SCARG(uap, osa)) { error = copyout(&osa, SCARG(uap, osa), sizeof(osa)); if (error) return (error); } return (0); } #endif /* ARGSUSED */ int sys___sigaction_sigtramp(struct lwp *l, void *v, register_t *retval) { struct sys___sigaction_sigtramp_args /* { syscallarg(int) signum; syscallarg(const struct sigaction *) nsa; syscallarg(struct sigaction *) osa; syscallarg(void *) tramp; syscallarg(int) vers; } */ *uap = v; struct proc *p = l->l_proc; struct sigaction nsa, osa; int error; if (SCARG(uap, nsa)) { error = copyin(SCARG(uap, nsa), &nsa, sizeof(nsa)); if (error) return (error); } error = sigaction1(p, SCARG(uap, signum), SCARG(uap, nsa) ? &nsa : 0, SCARG(uap, osa) ? &osa : 0, SCARG(uap, tramp), SCARG(uap, vers)); if (error) return (error); if (SCARG(uap, osa)) { error = copyout(&osa, SCARG(uap, osa), sizeof(osa)); if (error) return (error); } return (0); } /* * Initialize signal state for process 0; * set to ignore signals that are ignored by default and disable the signal * stack. */ void siginit(struct proc *p) { struct sigacts *ps; int signum, prop; ps = p->p_sigacts; sigemptyset(&contsigmask); sigemptyset(&stopsigmask); sigemptyset(&sigcantmask); for (signum = 1; signum < NSIG; signum++) { prop = sigprop[signum]; if (prop & SA_CONT) sigaddset(&contsigmask, signum); if (prop & SA_STOP) sigaddset(&stopsigmask, signum); if (prop & SA_CANTMASK) sigaddset(&sigcantmask, signum); if (prop & SA_IGNORE && signum != SIGCONT) sigaddset(&p->p_sigctx.ps_sigignore, signum); sigemptyset(&SIGACTION_PS(ps, signum).sa_mask); SIGACTION_PS(ps, signum).sa_flags = SA_RESTART; } sigemptyset(&p->p_sigctx.ps_sigcatch); p->p_sigctx.ps_sigwaited = NULL; p->p_flag &= ~P_NOCLDSTOP; /* * Reset stack state to the user stack. */ p->p_sigctx.ps_sigstk.ss_flags = SS_DISABLE; p->p_sigctx.ps_sigstk.ss_size = 0; p->p_sigctx.ps_sigstk.ss_sp = 0; /* One reference. */ ps->sa_refcnt = 1; } /* * Reset signals for an exec of the specified process. */ void execsigs(struct proc *p) { struct sigacts *ps; int signum, prop; sigactsunshare(p); ps = p->p_sigacts; /* * Reset caught signals. Held signals remain held * through p_sigctx.ps_sigmask (unless they were caught, * and are now ignored by default). */ for (signum = 1; signum < NSIG; signum++) { if (sigismember(&p->p_sigctx.ps_sigcatch, signum)) { prop = sigprop[signum]; if (prop & SA_IGNORE) { if ((prop & SA_CONT) == 0) sigaddset(&p->p_sigctx.ps_sigignore, signum); sigdelset(&p->p_sigctx.ps_siglist, signum); } SIGACTION_PS(ps, signum).sa_handler = SIG_DFL; } sigemptyset(&SIGACTION_PS(ps, signum).sa_mask); SIGACTION_PS(ps, signum).sa_flags = SA_RESTART; } sigemptyset(&p->p_sigctx.ps_sigcatch); p->p_sigctx.ps_sigwaited = NULL; /* * Reset no zombies if child dies flag as Solaris does. */ p->p_flag &= ~(P_NOCLDWAIT | P_CLDSIGIGN); if (SIGACTION_PS(ps, SIGCHLD).sa_handler == SIG_IGN) SIGACTION_PS(ps, SIGCHLD).sa_handler = SIG_DFL; /* * Reset stack state to the user stack. */ p->p_sigctx.ps_sigstk.ss_flags = SS_DISABLE; p->p_sigctx.ps_sigstk.ss_size = 0; p->p_sigctx.ps_sigstk.ss_sp = 0; } int sigprocmask1(struct proc *p, int how, const sigset_t *nss, sigset_t *oss) { if (oss) *oss = p->p_sigctx.ps_sigmask; if (nss) { (void)splsched(); /* XXXSMP */ switch (how) { case SIG_BLOCK: sigplusset(nss, &p->p_sigctx.ps_sigmask); break; case SIG_UNBLOCK: sigminusset(nss, &p->p_sigctx.ps_sigmask); CHECKSIGS(p); break; case SIG_SETMASK: p->p_sigctx.ps_sigmask = *nss; CHECKSIGS(p); break; default: (void)spl0(); /* XXXSMP */ return (EINVAL); } sigminusset(&sigcantmask, &p->p_sigctx.ps_sigmask); (void)spl0(); /* XXXSMP */ } return (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. */ int sys___sigprocmask14(struct lwp *l, void *v, register_t *retval) { struct sys___sigprocmask14_args /* { syscallarg(int) how; syscallarg(const sigset_t *) set; syscallarg(sigset_t *) oset; } */ *uap = v; struct proc *p; sigset_t nss, oss; int error; if (SCARG(uap, set)) { error = copyin(SCARG(uap, set), &nss, sizeof(nss)); if (error) return (error); } p = l->l_proc; error = sigprocmask1(p, SCARG(uap, how), SCARG(uap, set) ? &nss : 0, SCARG(uap, oset) ? &oss : 0); if (error) return (error); if (SCARG(uap, oset)) { error = copyout(&oss, SCARG(uap, oset), sizeof(oss)); if (error) return (error); } return (0); } void sigpending1(struct proc *p, sigset_t *ss) { *ss = p->p_sigctx.ps_siglist; sigminusset(&p->p_sigctx.ps_sigmask, ss); } /* ARGSUSED */ int sys___sigpending14(struct lwp *l, void *v, register_t *retval) { struct sys___sigpending14_args /* { syscallarg(sigset_t *) set; } */ *uap = v; struct proc *p; sigset_t ss; p = l->l_proc; sigpending1(p, &ss); return (copyout(&ss, SCARG(uap, set), sizeof(ss))); } int sigsuspend1(struct proc *p, const sigset_t *ss) { struct sigacts *ps; ps = p->p_sigacts; if (ss) { /* * 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 sigctx structure * to indicate this. */ p->p_sigctx.ps_oldmask = p->p_sigctx.ps_sigmask; p->p_sigctx.ps_flags |= SAS_OLDMASK; (void) splsched(); /* XXXSMP */ p->p_sigctx.ps_sigmask = *ss; CHECKSIGS(p); sigminusset(&sigcantmask, &p->p_sigctx.ps_sigmask); (void) spl0(); /* XXXSMP */ } while (tsleep((caddr_t) ps, PPAUSE|PCATCH, "pause", 0) == 0) /* void */; /* always return EINTR rather than ERESTART... */ return (EINTR); } /* * 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. */ /* ARGSUSED */ int sys___sigsuspend14(struct lwp *l, void *v, register_t *retval) { struct sys___sigsuspend14_args /* { syscallarg(const sigset_t *) set; } */ *uap = v; struct proc *p; sigset_t ss; int error; if (SCARG(uap, set)) { error = copyin(SCARG(uap, set), &ss, sizeof(ss)); if (error) return (error); } p = l->l_proc; return (sigsuspend1(p, SCARG(uap, set) ? &ss : 0)); } int sigaltstack1(struct proc *p, const struct sigaltstack *nss, struct sigaltstack *oss) { if (oss) *oss = p->p_sigctx.ps_sigstk; if (nss) { if (nss->ss_flags & ~SS_ALLBITS) return (EINVAL); if (nss->ss_flags & SS_DISABLE) { if (p->p_sigctx.ps_sigstk.ss_flags & SS_ONSTACK) return (EINVAL); } else { if (nss->ss_size < MINSIGSTKSZ) return (ENOMEM); } p->p_sigctx.ps_sigstk = *nss; } return (0); } /* ARGSUSED */ int sys___sigaltstack14(struct lwp *l, void *v, register_t *retval) { struct sys___sigaltstack14_args /* { syscallarg(const struct sigaltstack *) nss; syscallarg(struct sigaltstack *) oss; } */ *uap = v; struct proc *p; struct sigaltstack nss, oss; int error; if (SCARG(uap, nss)) { error = copyin(SCARG(uap, nss), &nss, sizeof(nss)); if (error) return (error); } p = l->l_proc; error = sigaltstack1(p, SCARG(uap, nss) ? &nss : 0, SCARG(uap, oss) ? &oss : 0); if (error) return (error); if (SCARG(uap, oss)) { error = copyout(&oss, SCARG(uap, oss), sizeof(oss)); if (error) return (error); } return (0); } /* ARGSUSED */ int sys_kill(struct lwp *l, void *v, register_t *retval) { struct sys_kill_args /* { syscallarg(int) pid; syscallarg(int) signum; } */ *uap = v; struct proc *cp, *p; struct pcred *pc; ksiginfo_t ksi; cp = l->l_proc; pc = cp->p_cred; if ((u_int)SCARG(uap, signum) >= NSIG) return (EINVAL); KSI_INIT(&ksi); ksi.ksi_signo = SCARG(uap, signum); ksi.ksi_code = SI_USER; ksi.ksi_pid = cp->p_pid; ksi.ksi_uid = cp->p_ucred->cr_uid; if (SCARG(uap, pid) > 0) { /* kill single process */ if ((p = pfind(SCARG(uap, pid))) == NULL) return (ESRCH); if (!CANSIGNAL(cp, pc, p, SCARG(uap, signum))) return (EPERM); if (SCARG(uap, signum)) kpsignal2(p, &ksi, 1); return (0); } switch (SCARG(uap, pid)) { case -1: /* broadcast signal */ return (killpg1(cp, &ksi, 0, 1)); case 0: /* signal own process group */ return (killpg1(cp, &ksi, 0, 0)); default: /* negative explicit process group */ return (killpg1(cp, &ksi, -SCARG(uap, pid), 0)); } /* NOTREACHED */ } /* * Common code for kill process group/broadcast kill. * cp is calling process. */ int killpg1(struct proc *cp, ksiginfo_t *ksi, int pgid, int all) { struct proc *p; struct pcred *pc; struct pgrp *pgrp; int nfound; int signum = ksi->ksi_signo; pc = cp->p_cred; nfound = 0; if (all) { /* * broadcast */ proclist_lock_read(); PROCLIST_FOREACH(p, &allproc) { if (p->p_pid <= 1 || p->p_flag & P_SYSTEM || p == cp || !CANSIGNAL(cp, pc, p, signum)) continue; nfound++; if (signum) kpsignal2(p, ksi, 1); } proclist_unlock_read(); } 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); } LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { if (p->p_pid <= 1 || p->p_flag & P_SYSTEM || !CANSIGNAL(cp, pc, p, signum)) continue; nfound++; if (signum && P_ZOMBIE(p) == 0) kpsignal2(p, ksi, 1); } } return (nfound ? 0 : ESRCH); } /* * Send a signal to a process group. */ void gsignal(int pgid, int signum) { ksiginfo_t ksi; KSI_INIT_EMPTY(&ksi); ksi.ksi_signo = signum; kgsignal(pgid, &ksi, NULL); } void kgsignal(int pgid, ksiginfo_t *ksi, void *data) { struct pgrp *pgrp; if (pgid && (pgrp = pgfind(pgid))) kpgsignal(pgrp, ksi, data, 0); } /* * Send a signal to a process group. If checktty is 1, * limit to members which have a controlling terminal. */ void pgsignal(struct pgrp *pgrp, int sig, int checkctty) { ksiginfo_t ksi; KSI_INIT_EMPTY(&ksi); ksi.ksi_signo = sig; kpgsignal(pgrp, &ksi, NULL, checkctty); } void kpgsignal(struct pgrp *pgrp, ksiginfo_t *ksi, void *data, int checkctty) { struct proc *p; if (pgrp) LIST_FOREACH(p, &pgrp->pg_members, p_pglist) if (checkctty == 0 || p->p_flag & P_CONTROLT) kpsignal(p, ksi, data); } /* * Send a signal caused by a trap to the current process. * If it will be caught immediately, deliver it with correct code. * Otherwise, post it normally. */ void trapsignal(struct lwp *l, const ksiginfo_t *ksi) { struct proc *p; struct sigacts *ps; int signum = ksi->ksi_signo; KASSERT(KSI_TRAP_P(ksi)); p = l->l_proc; ps = p->p_sigacts; if ((p->p_flag & P_TRACED) == 0 && sigismember(&p->p_sigctx.ps_sigcatch, signum) && !sigismember(&p->p_sigctx.ps_sigmask, signum)) { p->p_stats->p_ru.ru_nsignals++; #ifdef KTRACE if (KTRPOINT(p, KTR_PSIG)) ktrpsig(l, signum, SIGACTION_PS(ps, signum).sa_handler, &p->p_sigctx.ps_sigmask, ksi); #endif kpsendsig(l, ksi, &p->p_sigctx.ps_sigmask); (void) splsched(); /* XXXSMP */ sigplusset(&SIGACTION_PS(ps, signum).sa_mask, &p->p_sigctx.ps_sigmask); if (SIGACTION_PS(ps, signum).sa_flags & SA_RESETHAND) { sigdelset(&p->p_sigctx.ps_sigcatch, signum); if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) sigaddset(&p->p_sigctx.ps_sigignore, signum); SIGACTION_PS(ps, signum).sa_handler = SIG_DFL; } (void) spl0(); /* XXXSMP */ } else { p->p_sigctx.ps_lwp = l->l_lid; /* XXX for core dump/debugger */ p->p_sigctx.ps_signo = ksi->ksi_signo; p->p_sigctx.ps_code = ksi->ksi_trap; kpsignal2(p, ksi, 1); } } /* * Fill in signal information and signal the parent for a child status change. */ void child_psignal(struct proc *p, int dolock) { ksiginfo_t ksi; KSI_INIT(&ksi); ksi.ksi_signo = SIGCHLD; ksi.ksi_code = p->p_xstat == SIGCONT ? CLD_CONTINUED : CLD_STOPPED; ksi.ksi_pid = p->p_pid; ksi.ksi_uid = p->p_ucred->cr_uid; ksi.ksi_status = p->p_xstat; ksi.ksi_utime = p->p_stats->p_ru.ru_utime.tv_sec; ksi.ksi_stime = p->p_stats->p_ru.ru_stime.tv_sec; kpsignal2(p->p_pptr, &ksi, dolock); } /* * 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. * * XXXSMP: Invoked as psignal() or sched_psignal(). */ void psignal1(struct proc *p, int signum, int dolock) { ksiginfo_t ksi; KSI_INIT_EMPTY(&ksi); ksi.ksi_signo = signum; kpsignal2(p, &ksi, dolock); } void kpsignal1(struct proc *p, ksiginfo_t *ksi, void *data, int dolock) { if ((p->p_flag & P_WEXIT) == 0 && data) { size_t fd; struct filedesc *fdp = p->p_fd; ksi->ksi_fd = -1; for (fd = 0; fd < fdp->fd_nfiles; fd++) { struct file *fp = fdp->fd_ofiles[fd]; /* XXX: lock? */ if (fp && fp->f_data == data) { ksi->ksi_fd = fd; break; } } } kpsignal2(p, ksi, dolock); } static void kpsignal2(struct proc *p, const ksiginfo_t *ksi, int dolock) { struct lwp *l, *suspended = NULL; struct sadata_vp *vp; int s = 0, prop, allsusp; sig_t action; int signum = ksi->ksi_signo; #ifdef DIAGNOSTIC if (signum <= 0 || signum >= NSIG) panic("psignal signal number %d", signum); /* XXXSMP: works, but icky */ if (dolock) SCHED_ASSERT_UNLOCKED(); else SCHED_ASSERT_LOCKED(); #endif /* * Notify any interested parties in the signal. */ KNOTE(&p->p_klist, NOTE_SIGNAL | signum); prop = sigprop[signum]; /* * If proc is traced, always give parent a chance. */ if (p->p_flag & P_TRACED) { action = SIG_DFL; /* * If the process is being traced and the signal is being * caught, make sure to save any ksiginfo. */ if (sigismember(&p->p_sigctx.ps_sigcatch, signum)) ksiginfo_put(p, ksi); } else { /* * If the signal was the result of a trap, reset it * to default action if it's currently masked, so that it would * coredump immediatelly instead of spinning repeatedly * taking the signal. */ if (KSI_TRAP_P(ksi) && sigismember(&p->p_sigctx.ps_sigmask, signum) && !sigismember(&p->p_sigctx.ps_sigcatch, signum)) { sigdelset(&p->p_sigctx.ps_sigignore, signum); sigdelset(&p->p_sigctx.ps_sigcatch, signum); sigdelset(&p->p_sigctx.ps_sigmask, signum); SIGACTION(p, signum).sa_handler = SIG_DFL; } /* * If the signal is being ignored, * then we forget about it immediately. * (Note: we don't set SIGCONT in p_sigctx.ps_sigignore, * and if it is set to SIG_IGN, * action will be SIG_DFL here.) */ if (sigismember(&p->p_sigctx.ps_sigignore, signum)) return; if (sigismember(&p->p_sigctx.ps_sigmask, signum)) action = SIG_HOLD; else if (sigismember(&p->p_sigctx.ps_sigcatch, signum)) action = SIG_CATCH; else { action = SIG_DFL; if (prop & SA_KILL && p->p_nice > NZERO) p->p_nice = NZERO; /* * 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) return; } } if (prop & SA_CONT) sigminusset(&stopsigmask, &p->p_sigctx.ps_siglist); if (prop & SA_STOP) sigminusset(&contsigmask, &p->p_sigctx.ps_siglist); /* * If the signal doesn't have SA_CANTMASK (no override for SIGKILL, * please!), check if anything waits on it. If yes, save the * info into provided ps_sigwaited, and wake-up the waiter. * The signal won't be processed further here. */ if ((prop & SA_CANTMASK) == 0 && p->p_sigctx.ps_sigwaited && sigismember(p->p_sigctx.ps_sigwait, signum) && p->p_stat != SSTOP) { p->p_sigctx.ps_sigwaited->ksi_info = ksi->ksi_info; p->p_sigctx.ps_sigwaited = NULL; if (dolock) wakeup_one(&p->p_sigctx.ps_sigwait); else sched_wakeup(&p->p_sigctx.ps_sigwait); return; } sigaddset(&p->p_sigctx.ps_siglist, signum); /* CHECKSIGS() is "inlined" here. */ p->p_sigctx.ps_sigcheck = 1; /* * 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)) { ksiginfo_put(p, ksi); return; } /* XXXSMP: works, but icky */ if (dolock) SCHED_LOCK(s); if (p->p_flag & P_SA) { allsusp = 0; l = NULL; if (p->p_stat == SACTIVE) { SLIST_FOREACH(vp, &p->p_sa->sa_vps, savp_next) { l = vp->savp_lwp; KDASSERT(l != NULL); if (l->l_flag & L_SA_IDLE) { /* wakeup idle LWP */ goto found; /*NOTREACHED*/ } else if (l->l_flag & L_SA_YIELD) { /* idle LWP is already waking up */ goto out; /*NOTREACHED*/ } } SLIST_FOREACH(vp, &p->p_sa->sa_vps, savp_next) { l = vp->savp_lwp; if (l->l_stat == LSRUN || l->l_stat == LSONPROC) { signotify(p); goto out; /*NOTREACHED*/ } if (l->l_stat == LSSLEEP && l->l_flag & L_SINTR) { /* ok to signal vp lwp */ break; } else l = NULL; } } else if (p->p_stat == SSTOP) { SLIST_FOREACH(vp, &p->p_sa->sa_vps, savp_next) { l = vp->savp_lwp; if (l->l_stat == LSSLEEP && (l->l_flag & L_SINTR) != 0) break; l = NULL; } } } else if (p->p_nrlwps > 0 && (p->p_stat != SSTOP)) { /* * At least one LWP is running or on a run queue. * The signal will be noticed when one of them returns * to userspace. */ signotify(p); /* * The signal will be noticed very soon. */ goto out; /*NOTREACHED*/ } else { /* * Find out if any of the sleeps are interruptable, * and if all the live LWPs remaining are suspended. */ allsusp = 1; LIST_FOREACH(l, &p->p_lwps, l_sibling) { if (l->l_stat == LSSLEEP && l->l_flag & L_SINTR) break; if (l->l_stat == LSSUSPENDED) suspended = l; else if ((l->l_stat != LSZOMB) && (l->l_stat != LSDEAD)) allsusp = 0; } } found: switch (p->p_stat) { case SACTIVE: if (l != NULL && (p->p_flag & P_TRACED)) goto run; /* * If SIGCONT is default (or ignored) and process is * asleep, we are finished; the process should not * be awakened. */ if ((prop & SA_CONT) && action == SIG_DFL) { sigdelset(&p->p_sigctx.ps_siglist, signum); goto done; } /* * When a sleeping process receives a stop * signal, process immediately if possible. */ if ((prop & SA_STOP) && action == SIG_DFL) { /* * If a child holding parent blocked, * stopping could cause deadlock. */ if (p->p_flag & P_PPWAIT) { goto out; } sigdelset(&p->p_sigctx.ps_siglist, signum); p->p_xstat = signum; if ((p->p_pptr->p_flag & P_NOCLDSTOP) == 0) { /* * XXXSMP: recursive call; don't lock * the second time around. */ child_psignal(p, 0); } proc_stop(p, 1); /* XXXSMP: recurse? */ goto done; } if (l == NULL) { /* * Special case: SIGKILL of a process * which is entirely composed of * suspended LWPs should succeed. We * make this happen by unsuspending one of * them. */ if (allsusp && (signum == SIGKILL)) { lwp_continue(suspended); } goto done; } /* * All other (caught or default) signals * cause the process to run. */ goto runfast; /*NOTREACHED*/ case SSTOP: /* Process is stopped */ /* * If traced process is already stopped, * then no further action is necessary. */ if (p->p_flag & P_TRACED) goto done; /* * Kill signal always sets processes running, * if possible. */ if (signum == SIGKILL) { l = proc_unstop(p); if (l) goto runfast; goto done; } if (prop & SA_CONT) { /* * If SIGCONT is default (or ignored), * we continue the process but don't * leave the signal in ps_siglist, as * it has no further action. If * SIGCONT is held, we continue the * process and leave the signal in * ps_siglist. 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) sigdelset(&p->p_sigctx.ps_siglist, signum); l = proc_unstop(p); if (l && (action == SIG_CATCH)) goto runfast; goto out; } if (prop & SA_STOP) { /* * Already stopped, don't need to stop again. * (If we did the shell could get confused.) */ sigdelset(&p->p_sigctx.ps_siglist, signum); goto done; } /* * If a lwp is sleeping interruptibly, then * wake it up; it will run until the kernel * boundary, where it will stop in issignal(), * since p->p_stat is still SSTOP. When the * process is continued, it will be made * runnable and can look at the signal. */ if (l) goto run; goto out; case SIDL: /* Process is being created by fork */ /* XXX: We are not ready to receive signals yet */ goto done; default: /* Else what? */ panic("psignal: Invalid process state %d.", p->p_stat); } /*NOTREACHED*/ runfast: if (action == SIG_CATCH) { ksiginfo_put(p, ksi); action = SIG_HOLD; } /* * Raise priority to at least PUSER. */ if (l->l_priority > PUSER) l->l_priority = PUSER; run: if (action == SIG_CATCH) { ksiginfo_put(p, ksi); action = SIG_HOLD; } setrunnable(l); /* XXXSMP: recurse? */ out: if (action == SIG_CATCH) ksiginfo_put(p, ksi); done: /* XXXSMP: works, but icky */ if (dolock) SCHED_UNLOCK(s); } siginfo_t * siginfo_alloc(int flags) { return pool_get(&siginfo_pool, flags); } void siginfo_free(void *arg) { pool_put(&siginfo_pool, arg); } void kpsendsig(struct lwp *l, const ksiginfo_t *ksi, const sigset_t *mask) { struct proc *p = l->l_proc; struct lwp *le, *li; siginfo_t *si; int f; if (p->p_flag & P_SA) { /* XXXUPSXXX What if not on sa_vp ? */ f = l->l_flag & L_SA; l->l_flag &= ~L_SA; si = siginfo_alloc(PR_WAITOK); si->_info = ksi->ksi_info; le = li = NULL; if (KSI_TRAP_P(ksi)) le = l; else li = l; if (sa_upcall(l, SA_UPCALL_SIGNAL | SA_UPCALL_DEFER, le, li, sizeof(*si), si, siginfo_free) != 0) { siginfo_free(si); if (KSI_TRAP_P(ksi)) /* XXX What do we do here?? */; } l->l_flag |= f; return; } (*p->p_emul->e_sendsig)(ksi, mask); } static inline int firstsig(const sigset_t *); static inline int firstsig(const sigset_t *ss) { int sig; sig = ffs(ss->__bits[0]); if (sig != 0) return (sig); #if NSIG > 33 sig = ffs(ss->__bits[1]); if (sig != 0) return (sig + 32); #endif #if NSIG > 65 sig = ffs(ss->__bits[2]); if (sig != 0) return (sig + 64); #endif #if NSIG > 97 sig = ffs(ss->__bits[3]); if (sig != 0) return (sig + 96); #endif return (0); } /* * 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(curlwp)) * postsig(signum); */ int issignal(struct lwp *l) { struct proc *p = l->l_proc; int s = 0, signum, prop; int dolock = (l->l_flag & L_SINTR) == 0, locked = !dolock; sigset_t ss; /* Bail out if we do not own the virtual processor */ if (l->l_flag & L_SA && l->l_savp->savp_lwp != l) return 0; if (p->p_stat == SSTOP) { /* * The process is stopped/stopping. Stop ourselves now that * we're on the kernel/userspace boundary. */ if (dolock) SCHED_LOCK(s); l->l_stat = LSSTOP; p->p_nrlwps--; if (p->p_flag & P_TRACED) goto sigtraceswitch; else goto sigswitch; } for (;;) { sigpending1(p, &ss); if (p->p_flag & P_PPWAIT) sigminusset(&stopsigmask, &ss); signum = firstsig(&ss); if (signum == 0) { /* no signal to send */ p->p_sigctx.ps_sigcheck = 0; if (locked && dolock) SCHED_LOCK(s); return (0); } /* take the signal! */ sigdelset(&p->p_sigctx.ps_siglist, signum); /* * We should see pending but ignored signals * only if P_TRACED was on when they were posted. */ if (sigismember(&p->p_sigctx.ps_sigignore, signum) && (p->p_flag & P_TRACED) == 0) continue; if (p->p_flag & P_TRACED && (p->p_flag & P_PPWAIT) == 0) { /* * If traced, always stop, and stay * stopped until released by the debugger. */ p->p_xstat = signum; /* Emulation-specific handling of signal trace */ if ((p->p_emul->e_tracesig != NULL) && ((*p->p_emul->e_tracesig)(p, signum) != 0)) goto childresumed; if ((p->p_flag & P_FSTRACE) == 0) child_psignal(p, dolock); if (dolock) SCHED_LOCK(s); proc_stop(p, 1); sigtraceswitch: mi_switch(l, NULL); SCHED_ASSERT_UNLOCKED(); if (dolock) splx(s); else dolock = 1; childresumed: /* * If we are no longer being traced, or the parent * didn't give us a signal, look for more signals. */ if ((p->p_flag & P_TRACED) == 0 || p->p_xstat == 0) continue; /* * If the new signal is being masked, look for other * signals. */ signum = p->p_xstat; p->p_xstat = 0; /* * `p->p_sigctx.ps_siglist |= mask' is done * in setrunnable(). */ if (sigismember(&p->p_sigctx.ps_sigmask, signum)) continue; /* take the signal! */ sigdelset(&p->p_sigctx.ps_siglist, signum); } prop = sigprop[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)SIGACTION(p, signum).sa_handler) { case (long)SIG_DFL: /* * Don't take default actions on system processes. */ if (p->p_pid <= 1) { #ifdef 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; if ((p->p_pptr->p_flag & P_NOCLDSTOP) == 0) child_psignal(p, dolock); if (dolock) SCHED_LOCK(s); proc_stop(p, 1); sigswitch: mi_switch(l, NULL); SCHED_ASSERT_UNLOCKED(); if (dolock) splx(s); else dolock = 1; break; } else if (prop & SA_IGNORE) { /* * Except for SIGCONT, shouldn't get here. * Default action is to ignore; drop it. */ break; /* == ignore */ } else goto keep; /*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. */ #ifdef DEBUG_ISSIGNAL if ((prop & SA_CONT) == 0 && (p->p_flag & P_TRACED) == 0) printf("issignal\n"); #endif break; /* == ignore */ default: /* * This signal has an action, let * postsig() process it. */ goto keep; } } /* NOTREACHED */ keep: /* leave the signal for later */ sigaddset(&p->p_sigctx.ps_siglist, signum); CHECKSIGS(p); if (locked && dolock) SCHED_LOCK(s); return (signum); } /* * 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 proc_stop(struct proc *p, int dowakeup) { struct lwp *l; struct proc *parent; struct sadata_vp *vp; SCHED_ASSERT_LOCKED(); /* XXX lock process LWP state */ p->p_flag &= ~P_WAITED; p->p_stat = SSTOP; parent = p->p_pptr; parent->p_nstopchild++; if (p->p_flag & P_SA) { /* * Only (try to) put the LWP on the VP in stopped * state. * All other LWPs will suspend in sa_setwoken() * because the VP-LWP in stopped state cannot be * repossessed. */ SLIST_FOREACH(vp, &p->p_sa->sa_vps, savp_next) { l = vp->savp_lwp; if (l->l_stat == LSONPROC && l->l_cpu == curcpu()) { l->l_stat = LSSTOP; p->p_nrlwps--; } else if (l->l_stat == LSRUN) { /* Remove LWP from the run queue */ remrunqueue(l); l->l_stat = LSSTOP; p->p_nrlwps--; } else if (l->l_stat == LSSLEEP && l->l_flag & L_SA_IDLE) { l->l_flag &= ~L_SA_IDLE; l->l_stat = LSSTOP; } } goto out; } /* * Put as many LWP's as possible in stopped state. * Sleeping ones will notice the stopped state as they try to * return to userspace. */ LIST_FOREACH(l, &p->p_lwps, l_sibling) { if (l->l_stat == LSONPROC) { /* XXX SMP this assumes that a LWP that is LSONPROC * is curlwp and hence is about to be mi_switched * away; the only callers of proc_stop() are: * - psignal * - issignal() * For the former, proc_stop() is only called when * no processes are running, so we don't worry. * For the latter, proc_stop() is called right * before mi_switch(). */ l->l_stat = LSSTOP; p->p_nrlwps--; } else if (l->l_stat == LSRUN) { /* Remove LWP from the run queue */ remrunqueue(l); l->l_stat = LSSTOP; p->p_nrlwps--; } else if ((l->l_stat == LSSLEEP) || (l->l_stat == LSSUSPENDED) || (l->l_stat == LSZOMB) || (l->l_stat == LSDEAD)) { /* * Don't do anything; let sleeping LWPs * discover the stopped state of the process * on their way out of the kernel; otherwise, * things like NFS threads that sleep with * locks will block the rest of the system * from getting any work done. * * Suspended/dead/zombie LWPs aren't going * anywhere, so we don't need to touch them. */ } #ifdef DIAGNOSTIC else { panic("proc_stop: process %d lwp %d " "in unstoppable state %d.\n", p->p_pid, l->l_lid, l->l_stat); } #endif } out: /* XXX unlock process LWP state */ if (dowakeup) sched_wakeup((caddr_t)p->p_pptr); } /* * Given a process in state SSTOP, set the state back to SACTIVE and * move LSSTOP'd LWPs to LSSLEEP or make them runnable. * * If no LWPs ended up runnable (and therefore able to take a signal), * return a LWP that is sleeping interruptably. The caller can wake * that LWP up to take a signal. */ struct lwp * proc_unstop(struct proc *p) { struct lwp *l, *lr = NULL; struct sadata_vp *vp; int cantake = 0; SCHED_ASSERT_LOCKED(); /* * Our caller wants to be informed if there are only sleeping * and interruptable LWPs left after we have run so that it * can invoke setrunnable() if required - return one of the * interruptable LWPs if this is the case. */ if (!(p->p_flag & P_WAITED)) p->p_pptr->p_nstopchild--; p->p_stat = SACTIVE; LIST_FOREACH(l, &p->p_lwps, l_sibling) { if (l->l_stat == LSRUN) { lr = NULL; cantake = 1; } if (l->l_stat != LSSTOP) continue; if (l->l_wchan != NULL) { l->l_stat = LSSLEEP; if ((cantake == 0) && (l->l_flag & L_SINTR)) { lr = l; cantake = 1; } } else { setrunnable(l); lr = NULL; cantake = 1; } } if (p->p_flag & P_SA) { /* Only consider returning the LWP on the VP. */ SLIST_FOREACH(vp, &p->p_sa->sa_vps, savp_next) { lr = vp->savp_lwp; if (lr->l_stat == LSSLEEP) { if (lr->l_flag & L_SA_YIELD) { setrunnable(lr); break; } else if (lr->l_flag & L_SINTR) return lr; } } return NULL; } return lr; } /* * Take the action for the specified signal * from the current set of pending signals. */ void postsig(int signum) { struct lwp *l; struct proc *p; struct sigacts *ps; sig_t action; sigset_t *returnmask; l = curlwp; p = l->l_proc; ps = p->p_sigacts; #ifdef DIAGNOSTIC if (signum == 0) panic("postsig"); #endif KERNEL_PROC_LOCK(l); #ifdef MULTIPROCESSOR /* * On MP, issignal() can return the same signal to multiple * LWPs. The LWPs will block above waiting for the kernel * lock and the first LWP which gets through will then remove * the signal from ps_siglist. All other LWPs exit here. */ if (!sigismember(&p->p_sigctx.ps_siglist, signum)) { KERNEL_PROC_UNLOCK(l); return; } #endif sigdelset(&p->p_sigctx.ps_siglist, signum); action = SIGACTION_PS(ps, signum).sa_handler; if (action == SIG_DFL) { #ifdef KTRACE if (KTRPOINT(p, KTR_PSIG)) ktrpsig(l, signum, action, p->p_sigctx.ps_flags & SAS_OLDMASK ? &p->p_sigctx.ps_oldmask : &p->p_sigctx.ps_sigmask, NULL); #endif /* * Default action, where the default is to kill * the process. (Other cases were ignored above.) */ sigexit(l, signum); /* NOTREACHED */ } else { ksiginfo_t *ksi; /* * If we get here, the signal must be caught. */ #ifdef DIAGNOSTIC if (action == SIG_IGN || sigismember(&p->p_sigctx.ps_sigmask, signum)) panic("postsig action"); #endif /* * Set the new mask value and also defer further * occurrences 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 (p->p_sigctx.ps_flags & SAS_OLDMASK) { returnmask = &p->p_sigctx.ps_oldmask; p->p_sigctx.ps_flags &= ~SAS_OLDMASK; } else returnmask = &p->p_sigctx.ps_sigmask; p->p_stats->p_ru.ru_nsignals++; ksi = ksiginfo_get(p, signum); #ifdef KTRACE if (KTRPOINT(p, KTR_PSIG)) ktrpsig(l, signum, action, p->p_sigctx.ps_flags & SAS_OLDMASK ? &p->p_sigctx.ps_oldmask : &p->p_sigctx.ps_sigmask, ksi); #endif if (ksi == NULL) { ksiginfo_t ksi1; /* * we did not save any siginfo for this, either * because the signal was not caught, or because the * user did not request SA_SIGINFO */ KSI_INIT_EMPTY(&ksi1); ksi1.ksi_signo = signum; kpsendsig(l, &ksi1, returnmask); } else { kpsendsig(l, ksi, returnmask); pool_put(&ksiginfo_pool, ksi); } p->p_sigctx.ps_lwp = 0; p->p_sigctx.ps_code = 0; p->p_sigctx.ps_signo = 0; (void) splsched(); /* XXXSMP */ sigplusset(&SIGACTION_PS(ps, signum).sa_mask, &p->p_sigctx.ps_sigmask); if (SIGACTION_PS(ps, signum).sa_flags & SA_RESETHAND) { sigdelset(&p->p_sigctx.ps_sigcatch, signum); if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) sigaddset(&p->p_sigctx.ps_sigignore, signum); SIGACTION_PS(ps, signum).sa_handler = SIG_DFL; } (void) spl0(); /* XXXSMP */ } KERNEL_PROC_UNLOCK(l); } /* * Kill the current process for stated reason. */ void killproc(struct proc *p, const char *why) { log(LOG_ERR, "pid %d was killed: %s\n", p->p_pid, why); uprintf("sorry, pid %d was killed: %s\n", p->p_pid, why); psignal(p, SIGKILL); } /* * 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. */ #if defined(DEBUG) int kern_logsigexit = 1; /* not static to make public for sysctl */ #else int kern_logsigexit = 0; /* not static to make public for sysctl */ #endif static const char logcoredump[] = "pid %d (%s), uid %d: exited on signal %d (core dumped)\n"; static const char lognocoredump[] = "pid %d (%s), uid %d: exited on signal %d (core not dumped, err = %d)\n"; /* Wrapper function for use in p_userret */ static void lwp_coredump_hook(struct lwp *l, void *arg) { int s; /* * Suspend ourselves, so that the kernel stack and therefore * the userland registers saved in the trapframe are around * for coredump() to write them out. */ KERNEL_PROC_LOCK(l); l->l_flag &= ~L_DETACHED; SCHED_LOCK(s); l->l_stat = LSSUSPENDED; l->l_proc->p_nrlwps--; /* XXX NJWLWP check if this makes sense here: */ l->l_proc->p_stats->p_ru.ru_nvcsw++; mi_switch(l, NULL); SCHED_ASSERT_UNLOCKED(); splx(s); lwp_exit(l); } void sigexit(struct lwp *l, int signum) { struct proc *p; #if 0 struct lwp *l2; #endif int error, exitsig; p = l->l_proc; /* * Don't permit coredump() or exit1() multiple times * in the same process. */ if (p->p_flag & P_WEXIT) { KERNEL_PROC_UNLOCK(l); (*p->p_userret)(l, p->p_userret_arg); } p->p_flag |= P_WEXIT; /* We don't want to switch away from exiting. */ /* XXX multiprocessor: stop LWPs on other processors. */ #if 0 if (p->p_flag & P_SA) { LIST_FOREACH(l2, &p->p_lwps, l_sibling) l2->l_flag &= ~L_SA; p->p_flag &= ~P_SA; } #endif /* Make other LWPs stick around long enough to be dumped */ p->p_userret = lwp_coredump_hook; p->p_userret_arg = NULL; exitsig = signum; p->p_acflag |= AXSIG; if (sigprop[signum] & SA_CORE) { p->p_sigctx.ps_signo = signum; if ((error = coredump(l, NULL)) == 0) exitsig |= WCOREFLAG; if (kern_logsigexit) { /* XXX What if we ever have really large UIDs? */ int uid = p->p_cred && p->p_ucred ? (int) p->p_ucred->cr_uid : -1; if (error) log(LOG_INFO, lognocoredump, p->p_pid, p->p_comm, uid, signum, error); else log(LOG_INFO, logcoredump, p->p_pid, p->p_comm, uid, signum); } } exit1(l, W_EXITCODE(0, exitsig)); /* NOTREACHED */ } struct coredump_iostate { struct lwp *io_lwp; struct vnode *io_vp; struct ucred *io_cred; off_t io_offset; }; int coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len) { struct coredump_iostate *io = cookie; int error; error = vn_rdwr(UIO_WRITE, io->io_vp, __UNCONST(data), len, io->io_offset, segflg, IO_NODELOCKED|IO_UNIT, io->io_cred, NULL, segflg == UIO_USERSPACE ? io->io_lwp : NULL); if (error) { printf("pid %d (%s): %s write of %zu@%p at %lld failed: %d\n", io->io_lwp->l_proc->p_pid, io->io_lwp->l_proc->p_comm, segflg == UIO_USERSPACE ? "user" : "system", len, data, (long long) io->io_offset, error); return (error); } io->io_offset += len; return (0); } /* * Dump core, into a file named "progname.core" or "core" (depending on the * value of shortcorename), unless the process was setuid/setgid. */ int coredump(struct lwp *l, const char *pattern) { struct vnode *vp; struct proc *p; struct vmspace *vm; struct ucred *cred; struct nameidata nd; struct vattr vattr; struct mount *mp; struct coredump_iostate io; int error, error1; char *name = NULL; p = l->l_proc; vm = p->p_vmspace; cred = p->p_cred->pc_ucred; /* * Make sure the process has not set-id, to prevent data leaks, * unless it was specifically requested to allow set-id coredumps. */ if ((p->p_flag & P_SUGID) && !security_setidcore_dump) return EPERM; /* * Refuse to core if the data + stack + user size is larger than * the core dump limit. XXX THIS IS WRONG, because of mapped * data. */ if (USPACE + ctob(vm->vm_dsize + vm->vm_ssize) >= p->p_rlimit[RLIMIT_CORE].rlim_cur) return EFBIG; /* better error code? */ restart: /* * The core dump will go in the current working directory. Make * sure that the directory is still there and that the mount flags * allow us to write core dumps there. */ vp = p->p_cwdi->cwdi_cdir; if (vp->v_mount == NULL || (vp->v_mount->mnt_flag & MNT_NOCOREDUMP) != 0) { error = EPERM; goto done; } if ((p->p_flag & P_SUGID) && security_setidcore_dump) pattern = security_setidcore_path; if (pattern == NULL) pattern = p->p_limit->pl_corename; if (name == NULL) { name = PNBUF_GET(); } if ((error = build_corename(p, name, pattern, MAXPATHLEN)) != 0) goto done; NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, l); if ((error = vn_open(&nd, O_CREAT | O_NOFOLLOW | FWRITE, S_IRUSR | S_IWUSR)) != 0) goto done; vp = nd.ni_vp; if (vn_start_write(vp, &mp, V_NOWAIT) != 0) { VOP_UNLOCK(vp, 0); if ((error = vn_close(vp, FWRITE, cred, l)) != 0) goto done; if ((error = vn_start_write(NULL, &mp, V_WAIT | V_SLEEPONLY | V_PCATCH)) != 0) goto done; goto restart; } /* Don't dump to non-regular files or files with links. */ if (vp->v_type != VREG || VOP_GETATTR(vp, &vattr, cred, l) || vattr.va_nlink != 1) { error = EINVAL; goto out; } VATTR_NULL(&vattr); vattr.va_size = 0; if ((p->p_flag & P_SUGID) && security_setidcore_dump) { vattr.va_uid = security_setidcore_owner; vattr.va_gid = security_setidcore_group; vattr.va_mode = security_setidcore_mode; } VOP_LEASE(vp, l, cred, LEASE_WRITE); VOP_SETATTR(vp, &vattr, cred, l); p->p_acflag |= ACORE; io.io_lwp = l; io.io_vp = vp; io.io_cred = cred; io.io_offset = 0; /* Now dump the actual core file. */ error = (*p->p_execsw->es_coredump)(l, &io); out: VOP_UNLOCK(vp, 0); vn_finished_write(mp, 0); error1 = vn_close(vp, FWRITE, cred, l); if (error == 0) error = error1; done: if (name != NULL) PNBUF_PUT(name); return error; } /* * Nonexistent system call-- signal process (may want to handle it). * Flag error in case process won't see signal immediately (blocked or ignored). */ /* ARGSUSED */ int sys_nosys(struct lwp *l, void *v, register_t *retval) { struct proc *p; p = l->l_proc; psignal(p, SIGSYS); return (ENOSYS); } static int build_corename(struct proc *p, char *dst, const char *src, size_t len) { const char *s; char *d, *end; int i; for (s = src, d = dst, end = d + len; *s != '\0'; s++) { if (*s == '%') { switch (*(s + 1)) { case 'n': i = snprintf(d, end - d, "%s", p->p_comm); break; case 'p': i = snprintf(d, end - d, "%d", p->p_pid); break; case 'u': i = snprintf(d, end - d, "%.*s", (int)sizeof p->p_pgrp->pg_session->s_login, p->p_pgrp->pg_session->s_login); break; case 't': i = snprintf(d, end - d, "%ld", p->p_stats->p_start.tv_sec); break; default: goto copy; } d += i; s++; } else { copy: *d = *s; d++; } if (d >= end) return (ENAMETOOLONG); } *d = '\0'; return 0; } void getucontext(struct lwp *l, ucontext_t *ucp) { struct proc *p; p = l->l_proc; ucp->uc_flags = 0; ucp->uc_link = l->l_ctxlink; (void)sigprocmask1(p, 0, NULL, &ucp->uc_sigmask); ucp->uc_flags |= _UC_SIGMASK; /* * The (unsupplied) definition of the `current execution stack' * in the System V Interface Definition appears to allow returning * the main context stack. */ if ((p->p_sigctx.ps_sigstk.ss_flags & SS_ONSTACK) == 0) { ucp->uc_stack.ss_sp = (void *)USRSTACK; ucp->uc_stack.ss_size = ctob(p->p_vmspace->vm_ssize); ucp->uc_stack.ss_flags = 0; /* XXX, def. is Very Fishy */ } else { /* Simply copy alternate signal execution stack. */ ucp->uc_stack = p->p_sigctx.ps_sigstk; } ucp->uc_flags |= _UC_STACK; cpu_getmcontext(l, &ucp->uc_mcontext, &ucp->uc_flags); } /* ARGSUSED */ int sys_getcontext(struct lwp *l, void *v, register_t *retval) { struct sys_getcontext_args /* { syscallarg(struct __ucontext *) ucp; } */ *uap = v; ucontext_t uc; getucontext(l, &uc); return (copyout(&uc, SCARG(uap, ucp), sizeof (*SCARG(uap, ucp)))); } int setucontext(struct lwp *l, const ucontext_t *ucp) { struct proc *p; int error; p = l->l_proc; if ((error = cpu_setmcontext(l, &ucp->uc_mcontext, ucp->uc_flags)) != 0) return (error); l->l_ctxlink = ucp->uc_link; if ((ucp->uc_flags & _UC_SIGMASK) != 0) sigprocmask1(p, SIG_SETMASK, &ucp->uc_sigmask, NULL); /* * If there was stack information, update whether or not we are * still running on an alternate signal stack. */ if ((ucp->uc_flags & _UC_STACK) != 0) { if (ucp->uc_stack.ss_flags & SS_ONSTACK) p->p_sigctx.ps_sigstk.ss_flags |= SS_ONSTACK; else p->p_sigctx.ps_sigstk.ss_flags &= ~SS_ONSTACK; } return 0; } /* ARGSUSED */ int sys_setcontext(struct lwp *l, void *v, register_t *retval) { struct sys_setcontext_args /* { syscallarg(const ucontext_t *) ucp; } */ *uap = v; ucontext_t uc; int error; if (SCARG(uap, ucp) == NULL) /* i.e. end of uc_link chain */ exit1(l, W_EXITCODE(0, 0)); else if ((error = copyin(SCARG(uap, ucp), &uc, sizeof (uc))) != 0 || (error = setucontext(l, &uc)) != 0) return (error); return (EJUSTRETURN); } /* * sigtimedwait(2) system call, used also for implementation * of sigwaitinfo() and sigwait(). * * This only handles single LWP in signal wait. libpthread provides * it's own sigtimedwait() wrapper to DTRT WRT individual threads. */ int sys___sigtimedwait(struct lwp *l, void *v, register_t *retval) { return __sigtimedwait1(l, v, retval, copyout, copyin, copyout); } int __sigtimedwait1(struct lwp *l, void *v, register_t *retval, copyout_t put_info, copyin_t fetch_timeout, copyout_t put_timeout) { struct sys___sigtimedwait_args /* { syscallarg(const sigset_t *) set; syscallarg(siginfo_t *) info; syscallarg(struct timespec *) timeout; } */ *uap = v; sigset_t *waitset, twaitset; struct proc *p = l->l_proc; int error, signum, s; int timo = 0; struct timeval tvstart; struct timespec ts; ksiginfo_t *ksi; MALLOC(waitset, sigset_t *, sizeof(sigset_t), M_TEMP, M_WAITOK); if ((error = copyin(SCARG(uap, set), waitset, sizeof(sigset_t)))) { FREE(waitset, M_TEMP); return (error); } /* * Silently ignore SA_CANTMASK signals. psignal1() would * ignore SA_CANTMASK signals in waitset, we do this * only for the below siglist check. */ sigminusset(&sigcantmask, waitset); /* * First scan siglist and check if there is signal from * our waitset already pending. */ twaitset = *waitset; __sigandset(&p->p_sigctx.ps_siglist, &twaitset); if ((signum = firstsig(&twaitset))) { /* found pending signal */ sigdelset(&p->p_sigctx.ps_siglist, signum); ksi = ksiginfo_get(p, signum); if (!ksi) { /* No queued siginfo, manufacture one */ ksi = pool_get(&ksiginfo_pool, PR_WAITOK); KSI_INIT(ksi); ksi->ksi_info._signo = signum; ksi->ksi_info._code = SI_USER; } goto sig; } /* * Calculate timeout, if it was specified. */ if (SCARG(uap, timeout)) { uint64_t ms; if ((error = (*fetch_timeout)(SCARG(uap, timeout), &ts, sizeof(ts)))) return (error); ms = (ts.tv_sec * 1000) + (ts.tv_nsec / 1000000); timo = mstohz(ms); if (timo == 0 && ts.tv_sec == 0 && ts.tv_nsec > 0) timo = 1; if (timo <= 0) return (EAGAIN); /* * Remember current mono_time, it would be used in * ECANCELED/ERESTART case. */ s = splclock(); tvstart = mono_time; splx(s); } /* * Setup ps_sigwait list. Pass pointer to malloced memory * here; it's not possible to pass pointer to a structure * on current process's stack, the current process might * be swapped out at the time the signal would get delivered. */ ksi = pool_get(&ksiginfo_pool, PR_WAITOK); p->p_sigctx.ps_sigwaited = ksi; p->p_sigctx.ps_sigwait = waitset; /* * Wait for signal to arrive. We can either be woken up or * time out. */ error = tsleep(&p->p_sigctx.ps_sigwait, PPAUSE|PCATCH, "sigwait", timo); /* * Need to find out if we woke as a result of lwp_wakeup() * or a signal outside our wait set. */ if (error == EINTR && p->p_sigctx.ps_sigwaited && !firstsig(&p->p_sigctx.ps_siglist)) { /* wakeup via _lwp_wakeup() */ error = ECANCELED; } else if (!error && p->p_sigctx.ps_sigwaited) { /* spurious wakeup - arrange for syscall restart */ error = ERESTART; goto fail; } /* * On error, clear sigwait indication. psignal1() clears it * in !error case. */ if (error) { p->p_sigctx.ps_sigwaited = NULL; /* * If the sleep was interrupted (either by signal or wakeup), * update the timeout and copyout new value back. * It would be used when the syscall would be restarted * or called again. */ if (timo && (error == ERESTART || error == ECANCELED)) { struct timeval tvnow, tvtimo; int err; s = splclock(); tvnow = mono_time; splx(s); TIMESPEC_TO_TIMEVAL(&tvtimo, &ts); /* compute how much time has passed since start */ timersub(&tvnow, &tvstart, &tvnow); /* substract passed time from timeout */ timersub(&tvtimo, &tvnow, &tvtimo); if (tvtimo.tv_sec < 0) { error = EAGAIN; goto fail; } TIMEVAL_TO_TIMESPEC(&tvtimo, &ts); /* copy updated timeout to userland */ if ((err = (*put_timeout)(&ts, SCARG(uap, timeout), sizeof(ts)))) { error = err; goto fail; } } goto fail; } /* * If a signal from the wait set arrived, copy it to userland. * Copy only the used part of siginfo, the padding part is * left unchanged (userland is not supposed to touch it anyway). */ sig: return (*put_info)(&ksi->ksi_info, SCARG(uap, info), sizeof(ksi->ksi_info)); fail: FREE(waitset, M_TEMP); pool_put(&ksiginfo_pool, ksi); p->p_sigctx.ps_sigwait = NULL; return (error); } /* * Returns true if signal is ignored or masked for passed process. */ int sigismasked(struct proc *p, int sig) { return (sigismember(&p->p_sigctx.ps_sigignore, sig) || sigismember(&p->p_sigctx.ps_sigmask, sig)); } static int filt_sigattach(struct knote *kn) { struct proc *p = curproc; kn->kn_ptr.p_proc = p; kn->kn_flags |= EV_CLEAR; /* automatically set */ SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext); return (0); } static void filt_sigdetach(struct knote *kn) { struct proc *p = kn->kn_ptr.p_proc; SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext); } /* * signal knotes are shared with proc knotes, so we apply a mask to * the hint in order to differentiate them from process hints. This * could be avoided by using a signal-specific knote list, but probably * isn't worth the trouble. */ static int filt_signal(struct knote *kn, long hint) { if (hint & NOTE_SIGNAL) { hint &= ~NOTE_SIGNAL; if (kn->kn_id == hint) kn->kn_data++; } return (kn->kn_data != 0); } const struct filterops sig_filtops = { 0, filt_sigattach, filt_sigdetach, filt_signal };