diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c index cad8cc3edf98..c62b53ecc844 100644 --- a/sys/kern/kern_sig.c +++ b/sys/kern/kern_sig.c @@ -1,4467 +1,4467 @@ /*- * SPDX-License-Identifier: BSD-3-Clause * * 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 8.7 (Berkeley) 4/18/94 */ #include __FBSDID("$FreeBSD$"); #include "opt_ktrace.h" #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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define ONSIG 32 /* NSIG for osig* syscalls. XXX. */ SDT_PROVIDER_DECLARE(proc); SDT_PROBE_DEFINE3(proc, , , signal__send, "struct thread *", "struct proc *", "int"); SDT_PROBE_DEFINE2(proc, , , signal__clear, "int", "ksiginfo_t *"); SDT_PROBE_DEFINE3(proc, , , signal__discard, "struct thread *", "struct proc *", "int"); static int coredump(struct thread *); static int killpg1(struct thread *td, int sig, int pgid, int all, ksiginfo_t *ksi); static int issignal(struct thread *td); static void reschedule_signals(struct proc *p, sigset_t block, int flags); static int sigprop(int sig); static void tdsigwakeup(struct thread *, int, sig_t, int); static int sig_suspend_threads(struct thread *, struct proc *, int); static int filt_sigattach(struct knote *kn); static void filt_sigdetach(struct knote *kn); static int filt_signal(struct knote *kn, long hint); static struct thread *sigtd(struct proc *p, int sig, bool fast_sigblock); static void sigqueue_start(void); static void sigfastblock_setpend(struct thread *td, bool resched); static uma_zone_t ksiginfo_zone = NULL; struct filterops sig_filtops = { .f_isfd = 0, .f_attach = filt_sigattach, .f_detach = filt_sigdetach, .f_event = filt_signal, }; static int kern_logsigexit = 1; SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, &kern_logsigexit, 0, "Log processes quitting on abnormal signals to syslog(3)"); static int kern_forcesigexit = 1; SYSCTL_INT(_kern, OID_AUTO, forcesigexit, CTLFLAG_RW, &kern_forcesigexit, 0, "Force trap signal to be handled"); static SYSCTL_NODE(_kern, OID_AUTO, sigqueue, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, "POSIX real time signal"); static int max_pending_per_proc = 128; SYSCTL_INT(_kern_sigqueue, OID_AUTO, max_pending_per_proc, CTLFLAG_RW, &max_pending_per_proc, 0, "Max pending signals per proc"); static int preallocate_siginfo = 1024; SYSCTL_INT(_kern_sigqueue, OID_AUTO, preallocate, CTLFLAG_RDTUN, &preallocate_siginfo, 0, "Preallocated signal memory size"); static int signal_overflow = 0; SYSCTL_INT(_kern_sigqueue, OID_AUTO, overflow, CTLFLAG_RD, &signal_overflow, 0, "Number of signals overflew"); static int signal_alloc_fail = 0; SYSCTL_INT(_kern_sigqueue, OID_AUTO, alloc_fail, CTLFLAG_RD, &signal_alloc_fail, 0, "signals failed to be allocated"); static int kern_lognosys = 0; SYSCTL_INT(_kern, OID_AUTO, lognosys, CTLFLAG_RWTUN, &kern_lognosys, 0, "Log invalid syscalls"); __read_frequently bool sigfastblock_fetch_always = false; SYSCTL_BOOL(_kern, OID_AUTO, sigfastblock_fetch_always, CTLFLAG_RWTUN, &sigfastblock_fetch_always, 0, "Fetch sigfastblock word on each syscall entry for proper " "blocking semantic"); static bool kern_sig_discard_ign = true; SYSCTL_BOOL(_kern, OID_AUTO, sig_discard_ign, CTLFLAG_RWTUN, &kern_sig_discard_ign, 0, "Discard ignored signals on delivery, otherwise queue them to " "the target queue"); SYSINIT(signal, SI_SUB_P1003_1B, SI_ORDER_FIRST+3, sigqueue_start, NULL); /* * Policy -- Can ucred cr1 send SIGIO to process cr2? * Should use cr_cansignal() once cr_cansignal() allows SIGIO and SIGURG * in the right situations. */ #define CANSIGIO(cr1, cr2) \ ((cr1)->cr_uid == 0 || \ (cr1)->cr_ruid == (cr2)->cr_ruid || \ (cr1)->cr_uid == (cr2)->cr_ruid || \ (cr1)->cr_ruid == (cr2)->cr_uid || \ (cr1)->cr_uid == (cr2)->cr_uid) static int sugid_coredump; SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RWTUN, &sugid_coredump, 0, "Allow setuid and setgid processes to dump core"); static int capmode_coredump; SYSCTL_INT(_kern, OID_AUTO, capmode_coredump, CTLFLAG_RWTUN, &capmode_coredump, 0, "Allow processes in capability mode to dump core"); static int do_coredump = 1; SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, &do_coredump, 0, "Enable/Disable coredumps"); static int set_core_nodump_flag = 0; SYSCTL_INT(_kern, OID_AUTO, nodump_coredump, CTLFLAG_RW, &set_core_nodump_flag, 0, "Enable setting the NODUMP flag on coredump files"); static int coredump_devctl = 0; SYSCTL_INT(_kern, OID_AUTO, coredump_devctl, CTLFLAG_RW, &coredump_devctl, 0, "Generate a devctl notification when processes coredump"); /* * Signal properties and actions. * The array below categorizes the signals and their default actions * according to the following properties: */ #define SIGPROP_KILL 0x01 /* terminates process by default */ #define SIGPROP_CORE 0x02 /* ditto and coredumps */ #define SIGPROP_STOP 0x04 /* suspend process */ #define SIGPROP_TTYSTOP 0x08 /* ditto, from tty */ #define SIGPROP_IGNORE 0x10 /* ignore by default */ #define SIGPROP_CONT 0x20 /* continue if suspended */ static int sigproptbl[NSIG] = { [SIGHUP] = SIGPROP_KILL, [SIGINT] = SIGPROP_KILL, [SIGQUIT] = SIGPROP_KILL | SIGPROP_CORE, [SIGILL] = SIGPROP_KILL | SIGPROP_CORE, [SIGTRAP] = SIGPROP_KILL | SIGPROP_CORE, [SIGABRT] = SIGPROP_KILL | SIGPROP_CORE, [SIGEMT] = SIGPROP_KILL | SIGPROP_CORE, [SIGFPE] = SIGPROP_KILL | SIGPROP_CORE, [SIGKILL] = SIGPROP_KILL, [SIGBUS] = SIGPROP_KILL | SIGPROP_CORE, [SIGSEGV] = SIGPROP_KILL | SIGPROP_CORE, [SIGSYS] = SIGPROP_KILL | SIGPROP_CORE, [SIGPIPE] = SIGPROP_KILL, [SIGALRM] = SIGPROP_KILL, [SIGTERM] = SIGPROP_KILL, [SIGURG] = SIGPROP_IGNORE, [SIGSTOP] = SIGPROP_STOP, [SIGTSTP] = SIGPROP_STOP | SIGPROP_TTYSTOP, [SIGCONT] = SIGPROP_IGNORE | SIGPROP_CONT, [SIGCHLD] = SIGPROP_IGNORE, [SIGTTIN] = SIGPROP_STOP | SIGPROP_TTYSTOP, [SIGTTOU] = SIGPROP_STOP | SIGPROP_TTYSTOP, [SIGIO] = SIGPROP_IGNORE, [SIGXCPU] = SIGPROP_KILL, [SIGXFSZ] = SIGPROP_KILL, [SIGVTALRM] = SIGPROP_KILL, [SIGPROF] = SIGPROP_KILL, [SIGWINCH] = SIGPROP_IGNORE, [SIGINFO] = SIGPROP_IGNORE, [SIGUSR1] = SIGPROP_KILL, [SIGUSR2] = SIGPROP_KILL, }; #define _SIG_FOREACH_ADVANCE(i, set) ({ \ int __found; \ for (;;) { \ if (__bits != 0) { \ int __sig = ffs(__bits); \ __bits &= ~(1u << (__sig - 1)); \ sig = __i * sizeof((set)->__bits[0]) * NBBY + __sig; \ __found = 1; \ break; \ } \ if (++__i == _SIG_WORDS) { \ __found = 0; \ break; \ } \ __bits = (set)->__bits[__i]; \ } \ __found != 0; \ }) #define SIG_FOREACH(i, set) \ for (int32_t __i = -1, __bits = 0; \ _SIG_FOREACH_ADVANCE(i, set); ) \ static sigset_t fastblock_mask; static void ast_sig(struct thread *td, int tda) { struct proc *p; int sig; bool resched_sigs; p = td->td_proc; #ifdef DIAGNOSTIC if (p->p_numthreads == 1 && (tda & (TDAI(TDA_SIG) | TDAI(TDA_AST))) == 0) { PROC_LOCK(p); thread_lock(td); /* * Note that TDA_SIG should be re-read from * td_ast, since signal might have been delivered * after we cleared td_flags above. This is one of * the reason for looping check for AST condition. * See comment in userret() about P_PPWAIT. */ if ((p->p_flag & P_PPWAIT) == 0 && (td->td_pflags & TDP_SIGFASTBLOCK) == 0) { if (SIGPENDING(td) && ((tda | td->td_ast) & (TDAI(TDA_SIG) | TDAI(TDA_AST))) == 0) { thread_unlock(td); /* fix dumps */ panic( "failed2 to set signal flags for ast p %p " "td %p tda %#x td_ast %#x fl %#x", p, td, tda, td->td_ast, td->td_flags); } } thread_unlock(td); PROC_UNLOCK(p); } #endif /* * Check for signals. Unlocked reads of p_pendingcnt or * p_siglist might cause process-directed signal to be handled * later. */ - if ((tda & TDA_SIG) != 0 || p->p_pendingcnt > 0 || + if ((tda & TDAI(TDA_SIG)) != 0 || p->p_pendingcnt > 0 || !SIGISEMPTY(p->p_siglist)) { sigfastblock_fetch(td); PROC_LOCK(p); mtx_lock(&p->p_sigacts->ps_mtx); while ((sig = cursig(td)) != 0) { KASSERT(sig >= 0, ("sig %d", sig)); postsig(sig); } mtx_unlock(&p->p_sigacts->ps_mtx); PROC_UNLOCK(p); resched_sigs = true; } else { resched_sigs = false; } /* * Handle deferred update of the fast sigblock value, after * the postsig() loop was performed. */ sigfastblock_setpend(td, resched_sigs); } static void ast_sigsuspend(struct thread *td, int tda __unused) { MPASS((td->td_pflags & TDP_OLDMASK) != 0); td->td_pflags &= ~TDP_OLDMASK; kern_sigprocmask(td, SIG_SETMASK, &td->td_oldsigmask, NULL, 0); } static void sigqueue_start(void) { ksiginfo_zone = uma_zcreate("ksiginfo", sizeof(ksiginfo_t), NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0); uma_prealloc(ksiginfo_zone, preallocate_siginfo); p31b_setcfg(CTL_P1003_1B_REALTIME_SIGNALS, _POSIX_REALTIME_SIGNALS); p31b_setcfg(CTL_P1003_1B_RTSIG_MAX, SIGRTMAX - SIGRTMIN + 1); p31b_setcfg(CTL_P1003_1B_SIGQUEUE_MAX, max_pending_per_proc); SIGFILLSET(fastblock_mask); SIG_CANTMASK(fastblock_mask); ast_register(TDA_SIG, ASTR_UNCOND, 0, ast_sig); ast_register(TDA_SIGSUSPEND, ASTR_ASTF_REQUIRED | ASTR_TDP, TDP_OLDMASK, ast_sigsuspend); } ksiginfo_t * ksiginfo_alloc(int wait) { int flags; flags = M_ZERO | (wait ? M_WAITOK : M_NOWAIT); if (ksiginfo_zone != NULL) return ((ksiginfo_t *)uma_zalloc(ksiginfo_zone, flags)); return (NULL); } void ksiginfo_free(ksiginfo_t *ksi) { uma_zfree(ksiginfo_zone, ksi); } static __inline int ksiginfo_tryfree(ksiginfo_t *ksi) { if (!(ksi->ksi_flags & KSI_EXT)) { uma_zfree(ksiginfo_zone, ksi); return (1); } return (0); } void sigqueue_init(sigqueue_t *list, struct proc *p) { SIGEMPTYSET(list->sq_signals); SIGEMPTYSET(list->sq_kill); SIGEMPTYSET(list->sq_ptrace); TAILQ_INIT(&list->sq_list); list->sq_proc = p; list->sq_flags = SQ_INIT; } /* * Get a signal's ksiginfo. * Return: * 0 - signal not found * others - signal number */ static int sigqueue_get(sigqueue_t *sq, int signo, ksiginfo_t *si) { struct proc *p = sq->sq_proc; struct ksiginfo *ksi, *next; int count = 0; KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited")); if (!SIGISMEMBER(sq->sq_signals, signo)) return (0); if (SIGISMEMBER(sq->sq_ptrace, signo)) { count++; SIGDELSET(sq->sq_ptrace, signo); si->ksi_flags |= KSI_PTRACE; } if (SIGISMEMBER(sq->sq_kill, signo)) { count++; if (count == 1) SIGDELSET(sq->sq_kill, signo); } TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) { if (ksi->ksi_signo == signo) { if (count == 0) { TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link); ksi->ksi_sigq = NULL; ksiginfo_copy(ksi, si); if (ksiginfo_tryfree(ksi) && p != NULL) p->p_pendingcnt--; } if (++count > 1) break; } } if (count <= 1) SIGDELSET(sq->sq_signals, signo); si->ksi_signo = signo; return (signo); } void sigqueue_take(ksiginfo_t *ksi) { struct ksiginfo *kp; struct proc *p; sigqueue_t *sq; if (ksi == NULL || (sq = ksi->ksi_sigq) == NULL) return; p = sq->sq_proc; TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link); ksi->ksi_sigq = NULL; if (!(ksi->ksi_flags & KSI_EXT) && p != NULL) p->p_pendingcnt--; for (kp = TAILQ_FIRST(&sq->sq_list); kp != NULL; kp = TAILQ_NEXT(kp, ksi_link)) { if (kp->ksi_signo == ksi->ksi_signo) break; } if (kp == NULL && !SIGISMEMBER(sq->sq_kill, ksi->ksi_signo) && !SIGISMEMBER(sq->sq_ptrace, ksi->ksi_signo)) SIGDELSET(sq->sq_signals, ksi->ksi_signo); } static int sigqueue_add(sigqueue_t *sq, int signo, ksiginfo_t *si) { struct proc *p = sq->sq_proc; struct ksiginfo *ksi; int ret = 0; KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited")); /* * SIGKILL/SIGSTOP cannot be caught or masked, so take the fast path * for these signals. */ if (signo == SIGKILL || signo == SIGSTOP || si == NULL) { SIGADDSET(sq->sq_kill, signo); goto out_set_bit; } /* directly insert the ksi, don't copy it */ if (si->ksi_flags & KSI_INS) { if (si->ksi_flags & KSI_HEAD) TAILQ_INSERT_HEAD(&sq->sq_list, si, ksi_link); else TAILQ_INSERT_TAIL(&sq->sq_list, si, ksi_link); si->ksi_sigq = sq; goto out_set_bit; } if (__predict_false(ksiginfo_zone == NULL)) { SIGADDSET(sq->sq_kill, signo); goto out_set_bit; } if (p != NULL && p->p_pendingcnt >= max_pending_per_proc) { signal_overflow++; ret = EAGAIN; } else if ((ksi = ksiginfo_alloc(0)) == NULL) { signal_alloc_fail++; ret = EAGAIN; } else { if (p != NULL) p->p_pendingcnt++; ksiginfo_copy(si, ksi); ksi->ksi_signo = signo; if (si->ksi_flags & KSI_HEAD) TAILQ_INSERT_HEAD(&sq->sq_list, ksi, ksi_link); else TAILQ_INSERT_TAIL(&sq->sq_list, ksi, ksi_link); ksi->ksi_sigq = sq; } if (ret != 0) { if ((si->ksi_flags & KSI_PTRACE) != 0) { SIGADDSET(sq->sq_ptrace, signo); ret = 0; goto out_set_bit; } else if ((si->ksi_flags & KSI_TRAP) != 0 || (si->ksi_flags & KSI_SIGQ) == 0) { SIGADDSET(sq->sq_kill, signo); ret = 0; goto out_set_bit; } return (ret); } out_set_bit: SIGADDSET(sq->sq_signals, signo); return (ret); } void sigqueue_flush(sigqueue_t *sq) { struct proc *p = sq->sq_proc; ksiginfo_t *ksi; KASSERT(sq->sq_flags & SQ_INIT, ("sigqueue not inited")); if (p != NULL) PROC_LOCK_ASSERT(p, MA_OWNED); while ((ksi = TAILQ_FIRST(&sq->sq_list)) != NULL) { TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link); ksi->ksi_sigq = NULL; if (ksiginfo_tryfree(ksi) && p != NULL) p->p_pendingcnt--; } SIGEMPTYSET(sq->sq_signals); SIGEMPTYSET(sq->sq_kill); SIGEMPTYSET(sq->sq_ptrace); } static void sigqueue_move_set(sigqueue_t *src, sigqueue_t *dst, const sigset_t *set) { sigset_t tmp; struct proc *p1, *p2; ksiginfo_t *ksi, *next; KASSERT(src->sq_flags & SQ_INIT, ("src sigqueue not inited")); KASSERT(dst->sq_flags & SQ_INIT, ("dst sigqueue not inited")); p1 = src->sq_proc; p2 = dst->sq_proc; /* Move siginfo to target list */ TAILQ_FOREACH_SAFE(ksi, &src->sq_list, ksi_link, next) { if (SIGISMEMBER(*set, ksi->ksi_signo)) { TAILQ_REMOVE(&src->sq_list, ksi, ksi_link); if (p1 != NULL) p1->p_pendingcnt--; TAILQ_INSERT_TAIL(&dst->sq_list, ksi, ksi_link); ksi->ksi_sigq = dst; if (p2 != NULL) p2->p_pendingcnt++; } } /* Move pending bits to target list */ tmp = src->sq_kill; SIGSETAND(tmp, *set); SIGSETOR(dst->sq_kill, tmp); SIGSETNAND(src->sq_kill, tmp); tmp = src->sq_ptrace; SIGSETAND(tmp, *set); SIGSETOR(dst->sq_ptrace, tmp); SIGSETNAND(src->sq_ptrace, tmp); tmp = src->sq_signals; SIGSETAND(tmp, *set); SIGSETOR(dst->sq_signals, tmp); SIGSETNAND(src->sq_signals, tmp); } #if 0 static void sigqueue_move(sigqueue_t *src, sigqueue_t *dst, int signo) { sigset_t set; SIGEMPTYSET(set); SIGADDSET(set, signo); sigqueue_move_set(src, dst, &set); } #endif static void sigqueue_delete_set(sigqueue_t *sq, const sigset_t *set) { struct proc *p = sq->sq_proc; ksiginfo_t *ksi, *next; KASSERT(sq->sq_flags & SQ_INIT, ("src sigqueue not inited")); /* Remove siginfo queue */ TAILQ_FOREACH_SAFE(ksi, &sq->sq_list, ksi_link, next) { if (SIGISMEMBER(*set, ksi->ksi_signo)) { TAILQ_REMOVE(&sq->sq_list, ksi, ksi_link); ksi->ksi_sigq = NULL; if (ksiginfo_tryfree(ksi) && p != NULL) p->p_pendingcnt--; } } SIGSETNAND(sq->sq_kill, *set); SIGSETNAND(sq->sq_ptrace, *set); SIGSETNAND(sq->sq_signals, *set); } void sigqueue_delete(sigqueue_t *sq, int signo) { sigset_t set; SIGEMPTYSET(set); SIGADDSET(set, signo); sigqueue_delete_set(sq, &set); } /* Remove a set of signals for a process */ static void sigqueue_delete_set_proc(struct proc *p, const sigset_t *set) { sigqueue_t worklist; struct thread *td0; PROC_LOCK_ASSERT(p, MA_OWNED); sigqueue_init(&worklist, NULL); sigqueue_move_set(&p->p_sigqueue, &worklist, set); FOREACH_THREAD_IN_PROC(p, td0) sigqueue_move_set(&td0->td_sigqueue, &worklist, set); sigqueue_flush(&worklist); } void sigqueue_delete_proc(struct proc *p, int signo) { sigset_t set; SIGEMPTYSET(set); SIGADDSET(set, signo); sigqueue_delete_set_proc(p, &set); } static void sigqueue_delete_stopmask_proc(struct proc *p) { sigset_t set; SIGEMPTYSET(set); SIGADDSET(set, SIGSTOP); SIGADDSET(set, SIGTSTP); SIGADDSET(set, SIGTTIN); SIGADDSET(set, SIGTTOU); sigqueue_delete_set_proc(p, &set); } /* * Determine signal that should be delivered to thread td, the current * thread, 0 if none. If there is a pending stop signal with default * action, the process stops in issignal(). */ int cursig(struct thread *td) { PROC_LOCK_ASSERT(td->td_proc, MA_OWNED); mtx_assert(&td->td_proc->p_sigacts->ps_mtx, MA_OWNED); THREAD_LOCK_ASSERT(td, MA_NOTOWNED); return (SIGPENDING(td) ? issignal(td) : 0); } /* * Arrange for ast() to handle unmasked pending signals on return to user * mode. This must be called whenever a signal is added to td_sigqueue or * unmasked in td_sigmask. */ void signotify(struct thread *td) { PROC_LOCK_ASSERT(td->td_proc, MA_OWNED); if (SIGPENDING(td)) ast_sched(td, TDA_SIG); } /* * Returns 1 (true) if altstack is configured for the thread, and the * passed stack bottom address falls into the altstack range. Handles * the 43 compat special case where the alt stack size is zero. */ int sigonstack(size_t sp) { struct thread *td; td = curthread; if ((td->td_pflags & TDP_ALTSTACK) == 0) return (0); #if defined(COMPAT_43) if (SV_PROC_FLAG(td->td_proc, SV_AOUT) && td->td_sigstk.ss_size == 0) return ((td->td_sigstk.ss_flags & SS_ONSTACK) != 0); #endif return (sp >= (size_t)td->td_sigstk.ss_sp && sp < td->td_sigstk.ss_size + (size_t)td->td_sigstk.ss_sp); } static __inline int sigprop(int sig) { if (sig > 0 && sig < nitems(sigproptbl)) return (sigproptbl[sig]); return (0); } static bool sigact_flag_test(const struct sigaction *act, int flag) { /* * SA_SIGINFO is reset when signal disposition is set to * ignore or default. Other flags are kept according to user * settings. */ return ((act->sa_flags & flag) != 0 && (flag != SA_SIGINFO || ((__sighandler_t *)act->sa_sigaction != SIG_IGN && (__sighandler_t *)act->sa_sigaction != SIG_DFL))); } /* * kern_sigaction * sigaction * freebsd4_sigaction * osigaction */ int kern_sigaction(struct thread *td, int sig, const struct sigaction *act, struct sigaction *oact, int flags) { struct sigacts *ps; struct proc *p = td->td_proc; if (!_SIG_VALID(sig)) return (EINVAL); if (act != NULL && act->sa_handler != SIG_DFL && act->sa_handler != SIG_IGN && (act->sa_flags & ~(SA_ONSTACK | SA_RESTART | SA_RESETHAND | SA_NOCLDSTOP | SA_NODEFER | SA_NOCLDWAIT | SA_SIGINFO)) != 0) return (EINVAL); PROC_LOCK(p); ps = p->p_sigacts; mtx_lock(&ps->ps_mtx); if (oact) { memset(oact, 0, sizeof(*oact)); oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; if (SIGISMEMBER(ps->ps_sigonstack, sig)) oact->sa_flags |= SA_ONSTACK; if (!SIGISMEMBER(ps->ps_sigintr, sig)) oact->sa_flags |= SA_RESTART; if (SIGISMEMBER(ps->ps_sigreset, sig)) oact->sa_flags |= SA_RESETHAND; if (SIGISMEMBER(ps->ps_signodefer, sig)) oact->sa_flags |= SA_NODEFER; if (SIGISMEMBER(ps->ps_siginfo, sig)) { oact->sa_flags |= SA_SIGINFO; oact->sa_sigaction = (__siginfohandler_t *)ps->ps_sigact[_SIG_IDX(sig)]; } else oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDSTOP) oact->sa_flags |= SA_NOCLDSTOP; if (sig == SIGCHLD && ps->ps_flag & PS_NOCLDWAIT) oact->sa_flags |= SA_NOCLDWAIT; } if (act) { if ((sig == SIGKILL || sig == SIGSTOP) && act->sa_handler != SIG_DFL) { mtx_unlock(&ps->ps_mtx); PROC_UNLOCK(p); return (EINVAL); } /* * Change setting atomically. */ ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); if (sigact_flag_test(act, SA_SIGINFO)) { ps->ps_sigact[_SIG_IDX(sig)] = (__sighandler_t *)act->sa_sigaction; SIGADDSET(ps->ps_siginfo, sig); } else { ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; SIGDELSET(ps->ps_siginfo, sig); } if (!sigact_flag_test(act, SA_RESTART)) SIGADDSET(ps->ps_sigintr, sig); else SIGDELSET(ps->ps_sigintr, sig); if (sigact_flag_test(act, SA_ONSTACK)) SIGADDSET(ps->ps_sigonstack, sig); else SIGDELSET(ps->ps_sigonstack, sig); if (sigact_flag_test(act, SA_RESETHAND)) SIGADDSET(ps->ps_sigreset, sig); else SIGDELSET(ps->ps_sigreset, sig); if (sigact_flag_test(act, SA_NODEFER)) SIGADDSET(ps->ps_signodefer, sig); else SIGDELSET(ps->ps_signodefer, sig); if (sig == SIGCHLD) { if (act->sa_flags & SA_NOCLDSTOP) ps->ps_flag |= PS_NOCLDSTOP; else ps->ps_flag &= ~PS_NOCLDSTOP; if (act->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) ps->ps_flag &= ~PS_NOCLDWAIT; else ps->ps_flag |= PS_NOCLDWAIT; } else ps->ps_flag &= ~PS_NOCLDWAIT; if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) ps->ps_flag |= PS_CLDSIGIGN; else ps->ps_flag &= ~PS_CLDSIGIGN; } /* * Set bit in 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 ps_sigignore, as we * have to restart the process. */ if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || (sigprop(sig) & SIGPROP_IGNORE && ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { /* never to be seen again */ sigqueue_delete_proc(p, sig); if (sig != SIGCONT) /* easier in psignal */ SIGADDSET(ps->ps_sigignore, sig); SIGDELSET(ps->ps_sigcatch, sig); } else { SIGDELSET(ps->ps_sigignore, sig); if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) SIGDELSET(ps->ps_sigcatch, sig); else SIGADDSET(ps->ps_sigcatch, sig); } #ifdef COMPAT_FREEBSD4 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL || (flags & KSA_FREEBSD4) == 0) SIGDELSET(ps->ps_freebsd4, sig); else SIGADDSET(ps->ps_freebsd4, sig); #endif #ifdef COMPAT_43 if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL || (flags & KSA_OSIGSET) == 0) SIGDELSET(ps->ps_osigset, sig); else SIGADDSET(ps->ps_osigset, sig); #endif } mtx_unlock(&ps->ps_mtx); PROC_UNLOCK(p); return (0); } #ifndef _SYS_SYSPROTO_H_ struct sigaction_args { int sig; struct sigaction *act; struct sigaction *oact; }; #endif int sys_sigaction(struct thread *td, struct sigaction_args *uap) { struct sigaction act, oact; struct sigaction *actp, *oactp; int error; actp = (uap->act != NULL) ? &act : NULL; oactp = (uap->oact != NULL) ? &oact : NULL; if (actp) { error = copyin(uap->act, actp, sizeof(act)); if (error) return (error); } error = kern_sigaction(td, uap->sig, actp, oactp, 0); if (oactp && !error) error = copyout(oactp, uap->oact, sizeof(oact)); return (error); } #ifdef COMPAT_FREEBSD4 #ifndef _SYS_SYSPROTO_H_ struct freebsd4_sigaction_args { int sig; struct sigaction *act; struct sigaction *oact; }; #endif int freebsd4_sigaction(struct thread *td, struct freebsd4_sigaction_args *uap) { struct sigaction act, oact; struct sigaction *actp, *oactp; int error; actp = (uap->act != NULL) ? &act : NULL; oactp = (uap->oact != NULL) ? &oact : NULL; if (actp) { error = copyin(uap->act, actp, sizeof(act)); if (error) return (error); } error = kern_sigaction(td, uap->sig, actp, oactp, KSA_FREEBSD4); if (oactp && !error) error = copyout(oactp, uap->oact, sizeof(oact)); return (error); } #endif /* COMAPT_FREEBSD4 */ #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */ #ifndef _SYS_SYSPROTO_H_ struct osigaction_args { int signum; struct osigaction *nsa; struct osigaction *osa; }; #endif int osigaction(struct thread *td, struct osigaction_args *uap) { struct osigaction sa; struct sigaction nsa, osa; struct sigaction *nsap, *osap; int error; if (uap->signum <= 0 || uap->signum >= ONSIG) return (EINVAL); nsap = (uap->nsa != NULL) ? &nsa : NULL; osap = (uap->osa != NULL) ? &osa : NULL; if (nsap) { error = copyin(uap->nsa, &sa, sizeof(sa)); if (error) return (error); nsap->sa_handler = sa.sa_handler; nsap->sa_flags = sa.sa_flags; OSIG2SIG(sa.sa_mask, nsap->sa_mask); } error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET); if (osap && !error) { sa.sa_handler = osap->sa_handler; sa.sa_flags = osap->sa_flags; SIG2OSIG(osap->sa_mask, sa.sa_mask); error = copyout(&sa, uap->osa, sizeof(sa)); } return (error); } #if !defined(__i386__) /* Avoid replicating the same stub everywhere */ int osigreturn(struct thread *td, struct osigreturn_args *uap) { return (nosys(td, (struct nosys_args *)uap)); } #endif #endif /* COMPAT_43 */ /* * Initialize signal state for process 0; * set to ignore signals that are ignored by default. */ void siginit(struct proc *p) { int i; struct sigacts *ps; PROC_LOCK(p); ps = p->p_sigacts; mtx_lock(&ps->ps_mtx); for (i = 1; i <= NSIG; i++) { if (sigprop(i) & SIGPROP_IGNORE && i != SIGCONT) { SIGADDSET(ps->ps_sigignore, i); } } mtx_unlock(&ps->ps_mtx); PROC_UNLOCK(p); } /* * Reset specified signal to the default disposition. */ static void sigdflt(struct sigacts *ps, int sig) { mtx_assert(&ps->ps_mtx, MA_OWNED); SIGDELSET(ps->ps_sigcatch, sig); if ((sigprop(sig) & SIGPROP_IGNORE) != 0 && sig != SIGCONT) SIGADDSET(ps->ps_sigignore, sig); ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; SIGDELSET(ps->ps_siginfo, sig); } /* * Reset signals for an exec of the specified process. */ void execsigs(struct proc *p) { struct sigacts *ps; struct thread *td; /* * Reset caught signals. Held signals remain held * through td_sigmask (unless they were caught, * and are now ignored by default). */ PROC_LOCK_ASSERT(p, MA_OWNED); ps = p->p_sigacts; mtx_lock(&ps->ps_mtx); sig_drop_caught(p); /* * Reset stack state to the user stack. * Clear set of signals caught on the signal stack. */ td = curthread; MPASS(td->td_proc == p); td->td_sigstk.ss_flags = SS_DISABLE; td->td_sigstk.ss_size = 0; td->td_sigstk.ss_sp = 0; td->td_pflags &= ~TDP_ALTSTACK; /* * Reset no zombies if child dies flag as Solaris does. */ ps->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN); if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL; mtx_unlock(&ps->ps_mtx); } /* * kern_sigprocmask() * * Manipulate signal mask. */ int kern_sigprocmask(struct thread *td, int how, sigset_t *set, sigset_t *oset, int flags) { sigset_t new_block, oset1; struct proc *p; int error; p = td->td_proc; if ((flags & SIGPROCMASK_PROC_LOCKED) != 0) PROC_LOCK_ASSERT(p, MA_OWNED); else PROC_LOCK(p); mtx_assert(&p->p_sigacts->ps_mtx, (flags & SIGPROCMASK_PS_LOCKED) != 0 ? MA_OWNED : MA_NOTOWNED); if (oset != NULL) *oset = td->td_sigmask; error = 0; if (set != NULL) { switch (how) { case SIG_BLOCK: SIG_CANTMASK(*set); oset1 = td->td_sigmask; SIGSETOR(td->td_sigmask, *set); new_block = td->td_sigmask; SIGSETNAND(new_block, oset1); break; case SIG_UNBLOCK: SIGSETNAND(td->td_sigmask, *set); signotify(td); goto out; case SIG_SETMASK: SIG_CANTMASK(*set); oset1 = td->td_sigmask; if (flags & SIGPROCMASK_OLD) SIGSETLO(td->td_sigmask, *set); else td->td_sigmask = *set; new_block = td->td_sigmask; SIGSETNAND(new_block, oset1); signotify(td); break; default: error = EINVAL; goto out; } /* * The new_block set contains signals that were not previously * blocked, but are blocked now. * * In case we block any signal that was not previously blocked * for td, and process has the signal pending, try to schedule * signal delivery to some thread that does not block the * signal, possibly waking it up. */ if (p->p_numthreads != 1) reschedule_signals(p, new_block, flags); } out: if (!(flags & SIGPROCMASK_PROC_LOCKED)) PROC_UNLOCK(p); return (error); } #ifndef _SYS_SYSPROTO_H_ struct sigprocmask_args { int how; const sigset_t *set; sigset_t *oset; }; #endif int sys_sigprocmask(struct thread *td, struct sigprocmask_args *uap) { sigset_t set, oset; sigset_t *setp, *osetp; int error; setp = (uap->set != NULL) ? &set : NULL; osetp = (uap->oset != NULL) ? &oset : NULL; if (setp) { error = copyin(uap->set, setp, sizeof(set)); if (error) return (error); } error = kern_sigprocmask(td, uap->how, setp, osetp, 0); if (osetp && !error) { error = copyout(osetp, uap->oset, sizeof(oset)); } return (error); } #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */ #ifndef _SYS_SYSPROTO_H_ struct osigprocmask_args { int how; osigset_t mask; }; #endif int osigprocmask(struct thread *td, struct osigprocmask_args *uap) { sigset_t set, oset; int error; OSIG2SIG(uap->mask, set); error = kern_sigprocmask(td, uap->how, &set, &oset, 1); SIG2OSIG(oset, td->td_retval[0]); return (error); } #endif /* COMPAT_43 */ int sys_sigwait(struct thread *td, struct sigwait_args *uap) { ksiginfo_t ksi; sigset_t set; int error; error = copyin(uap->set, &set, sizeof(set)); if (error) { td->td_retval[0] = error; return (0); } error = kern_sigtimedwait(td, set, &ksi, NULL); if (error) { /* * sigwait() function shall not return EINTR, but * the syscall does. Non-ancient libc provides the * wrapper which hides EINTR. Otherwise, EINTR return * is used by libthr to handle required cancellation * point in the sigwait(). */ if (error == EINTR && td->td_proc->p_osrel < P_OSREL_SIGWAIT) return (ERESTART); td->td_retval[0] = error; return (0); } error = copyout(&ksi.ksi_signo, uap->sig, sizeof(ksi.ksi_signo)); td->td_retval[0] = error; return (0); } int sys_sigtimedwait(struct thread *td, struct sigtimedwait_args *uap) { struct timespec ts; struct timespec *timeout; sigset_t set; ksiginfo_t ksi; int error; if (uap->timeout) { error = copyin(uap->timeout, &ts, sizeof(ts)); if (error) return (error); timeout = &ts; } else timeout = NULL; error = copyin(uap->set, &set, sizeof(set)); if (error) return (error); error = kern_sigtimedwait(td, set, &ksi, timeout); if (error) return (error); if (uap->info) error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t)); if (error == 0) td->td_retval[0] = ksi.ksi_signo; return (error); } int sys_sigwaitinfo(struct thread *td, struct sigwaitinfo_args *uap) { ksiginfo_t ksi; sigset_t set; int error; error = copyin(uap->set, &set, sizeof(set)); if (error) return (error); error = kern_sigtimedwait(td, set, &ksi, NULL); if (error) return (error); if (uap->info) error = copyout(&ksi.ksi_info, uap->info, sizeof(siginfo_t)); if (error == 0) td->td_retval[0] = ksi.ksi_signo; return (error); } static void proc_td_siginfo_capture(struct thread *td, siginfo_t *si) { struct thread *thr; FOREACH_THREAD_IN_PROC(td->td_proc, thr) { if (thr == td) thr->td_si = *si; else thr->td_si.si_signo = 0; } } int kern_sigtimedwait(struct thread *td, sigset_t waitset, ksiginfo_t *ksi, struct timespec *timeout) { struct sigacts *ps; sigset_t saved_mask, new_block; struct proc *p; int error, sig, timevalid = 0; sbintime_t sbt, precision, tsbt; struct timespec ts; bool traced; p = td->td_proc; error = 0; traced = false; /* Ensure the sigfastblock value is up to date. */ sigfastblock_fetch(td); if (timeout != NULL) { if (timeout->tv_nsec >= 0 && timeout->tv_nsec < 1000000000) { timevalid = 1; ts = *timeout; if (ts.tv_sec < INT32_MAX / 2) { tsbt = tstosbt(ts); precision = tsbt; precision >>= tc_precexp; if (TIMESEL(&sbt, tsbt)) sbt += tc_tick_sbt; sbt += tsbt; } else precision = sbt = 0; } } else precision = sbt = 0; ksiginfo_init(ksi); /* Some signals can not be waited for. */ SIG_CANTMASK(waitset); ps = p->p_sigacts; PROC_LOCK(p); saved_mask = td->td_sigmask; SIGSETNAND(td->td_sigmask, waitset); if ((p->p_sysent->sv_flags & SV_SIG_DISCIGN) != 0 || !kern_sig_discard_ign) { thread_lock(td); td->td_flags |= TDF_SIGWAIT; thread_unlock(td); } for (;;) { mtx_lock(&ps->ps_mtx); sig = cursig(td); mtx_unlock(&ps->ps_mtx); KASSERT(sig >= 0, ("sig %d", sig)); if (sig != 0 && SIGISMEMBER(waitset, sig)) { if (sigqueue_get(&td->td_sigqueue, sig, ksi) != 0 || sigqueue_get(&p->p_sigqueue, sig, ksi) != 0) { error = 0; break; } } if (error != 0) break; /* * POSIX says this must be checked after looking for pending * signals. */ if (timeout != NULL && !timevalid) { error = EINVAL; break; } if (traced) { error = EINTR; break; } error = msleep_sbt(&p->p_sigacts, &p->p_mtx, PPAUSE | PCATCH, "sigwait", sbt, precision, C_ABSOLUTE); /* The syscalls can not be restarted. */ if (error == ERESTART) error = EINTR; /* * If PTRACE_SCE or PTRACE_SCX were set after * userspace entered the syscall, return spurious * EINTR after wait was done. Only do this as last * resort after rechecking for possible queued signals * and expired timeouts. */ if (error == 0 && (p->p_ptevents & PTRACE_SYSCALL) != 0) traced = true; } thread_lock(td); td->td_flags &= ~TDF_SIGWAIT; thread_unlock(td); new_block = saved_mask; SIGSETNAND(new_block, td->td_sigmask); td->td_sigmask = saved_mask; /* * Fewer signals can be delivered to us, reschedule signal * notification. */ if (p->p_numthreads != 1) reschedule_signals(p, new_block, 0); if (error == 0) { SDT_PROBE2(proc, , , signal__clear, sig, ksi); if (ksi->ksi_code == SI_TIMER) itimer_accept(p, ksi->ksi_timerid, ksi); #ifdef KTRACE if (KTRPOINT(td, KTR_PSIG)) { sig_t action; mtx_lock(&ps->ps_mtx); action = ps->ps_sigact[_SIG_IDX(sig)]; mtx_unlock(&ps->ps_mtx); ktrpsig(sig, action, &td->td_sigmask, ksi->ksi_code); } #endif if (sig == SIGKILL) { proc_td_siginfo_capture(td, &ksi->ksi_info); sigexit(td, sig); } } PROC_UNLOCK(p); return (error); } #ifndef _SYS_SYSPROTO_H_ struct sigpending_args { sigset_t *set; }; #endif int sys_sigpending(struct thread *td, struct sigpending_args *uap) { struct proc *p = td->td_proc; sigset_t pending; PROC_LOCK(p); pending = p->p_sigqueue.sq_signals; SIGSETOR(pending, td->td_sigqueue.sq_signals); PROC_UNLOCK(p); return (copyout(&pending, uap->set, sizeof(sigset_t))); } #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */ #ifndef _SYS_SYSPROTO_H_ struct osigpending_args { int dummy; }; #endif int osigpending(struct thread *td, struct osigpending_args *uap) { struct proc *p = td->td_proc; sigset_t pending; PROC_LOCK(p); pending = p->p_sigqueue.sq_signals; SIGSETOR(pending, td->td_sigqueue.sq_signals); PROC_UNLOCK(p); SIG2OSIG(pending, td->td_retval[0]); return (0); } #endif /* COMPAT_43 */ #if defined(COMPAT_43) /* * Generalized interface signal handler, 4.3-compatible. */ #ifndef _SYS_SYSPROTO_H_ struct osigvec_args { int signum; struct sigvec *nsv; struct sigvec *osv; }; #endif /* ARGSUSED */ int osigvec(struct thread *td, struct osigvec_args *uap) { struct sigvec vec; struct sigaction nsa, osa; struct sigaction *nsap, *osap; int error; if (uap->signum <= 0 || uap->signum >= ONSIG) return (EINVAL); nsap = (uap->nsv != NULL) ? &nsa : NULL; osap = (uap->osv != NULL) ? &osa : NULL; if (nsap) { error = copyin(uap->nsv, &vec, sizeof(vec)); if (error) return (error); nsap->sa_handler = vec.sv_handler; OSIG2SIG(vec.sv_mask, nsap->sa_mask); nsap->sa_flags = vec.sv_flags; nsap->sa_flags ^= SA_RESTART; /* opposite of SV_INTERRUPT */ } error = kern_sigaction(td, uap->signum, nsap, osap, KSA_OSIGSET); if (osap && !error) { vec.sv_handler = osap->sa_handler; SIG2OSIG(osap->sa_mask, vec.sv_mask); vec.sv_flags = osap->sa_flags; vec.sv_flags &= ~SA_NOCLDWAIT; vec.sv_flags ^= SA_RESTART; error = copyout(&vec, uap->osv, sizeof(vec)); } return (error); } #ifndef _SYS_SYSPROTO_H_ struct osigblock_args { int mask; }; #endif int osigblock(struct thread *td, struct osigblock_args *uap) { sigset_t set, oset; OSIG2SIG(uap->mask, set); kern_sigprocmask(td, SIG_BLOCK, &set, &oset, 0); SIG2OSIG(oset, td->td_retval[0]); return (0); } #ifndef _SYS_SYSPROTO_H_ struct osigsetmask_args { int mask; }; #endif int osigsetmask(struct thread *td, struct osigsetmask_args *uap) { sigset_t set, oset; OSIG2SIG(uap->mask, set); kern_sigprocmask(td, SIG_SETMASK, &set, &oset, 0); SIG2OSIG(oset, td->td_retval[0]); return (0); } #endif /* COMPAT_43 */ /* * Suspend calling thread until signal, providing mask to be set in the * meantime. */ #ifndef _SYS_SYSPROTO_H_ struct sigsuspend_args { const sigset_t *sigmask; }; #endif /* ARGSUSED */ int sys_sigsuspend(struct thread *td, struct sigsuspend_args *uap) { sigset_t mask; int error; error = copyin(uap->sigmask, &mask, sizeof(mask)); if (error) return (error); return (kern_sigsuspend(td, mask)); } int kern_sigsuspend(struct thread *td, sigset_t mask) { struct proc *p = td->td_proc; int has_sig, sig; /* Ensure the sigfastblock value is up to date. */ sigfastblock_fetch(td); /* * When returning from sigsuspend, 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. */ PROC_LOCK(p); kern_sigprocmask(td, SIG_SETMASK, &mask, &td->td_oldsigmask, SIGPROCMASK_PROC_LOCKED); td->td_pflags |= TDP_OLDMASK; ast_sched(td, TDA_SIGSUSPEND); /* * Process signals now. Otherwise, we can get spurious wakeup * due to signal entered process queue, but delivered to other * thread. But sigsuspend should return only on signal * delivery. */ (p->p_sysent->sv_set_syscall_retval)(td, EINTR); for (has_sig = 0; !has_sig;) { while (msleep(&p->p_sigacts, &p->p_mtx, PPAUSE|PCATCH, "pause", 0) == 0) /* void */; thread_suspend_check(0); mtx_lock(&p->p_sigacts->ps_mtx); while ((sig = cursig(td)) != 0) { KASSERT(sig >= 0, ("sig %d", sig)); has_sig += postsig(sig); } mtx_unlock(&p->p_sigacts->ps_mtx); /* * If PTRACE_SCE or PTRACE_SCX were set after * userspace entered the syscall, return spurious * EINTR. */ if ((p->p_ptevents & PTRACE_SYSCALL) != 0) has_sig += 1; } PROC_UNLOCK(p); td->td_errno = EINTR; td->td_pflags |= TDP_NERRNO; return (EJUSTRETURN); } #ifdef COMPAT_43 /* XXX - COMPAT_FBSD3 */ /* * Compatibility sigsuspend call for old binaries. Note nonstandard calling * convention: libc stub passes mask, not pointer, to save a copyin. */ #ifndef _SYS_SYSPROTO_H_ struct osigsuspend_args { osigset_t mask; }; #endif /* ARGSUSED */ int osigsuspend(struct thread *td, struct osigsuspend_args *uap) { sigset_t mask; OSIG2SIG(uap->mask, mask); return (kern_sigsuspend(td, mask)); } #endif /* COMPAT_43 */ #if defined(COMPAT_43) #ifndef _SYS_SYSPROTO_H_ struct osigstack_args { struct sigstack *nss; struct sigstack *oss; }; #endif /* ARGSUSED */ int osigstack(struct thread *td, struct osigstack_args *uap) { struct sigstack nss, oss; int error = 0; if (uap->nss != NULL) { error = copyin(uap->nss, &nss, sizeof(nss)); if (error) return (error); } oss.ss_sp = td->td_sigstk.ss_sp; oss.ss_onstack = sigonstack(cpu_getstack(td)); if (uap->nss != NULL) { td->td_sigstk.ss_sp = nss.ss_sp; td->td_sigstk.ss_size = 0; td->td_sigstk.ss_flags |= nss.ss_onstack & SS_ONSTACK; td->td_pflags |= TDP_ALTSTACK; } if (uap->oss != NULL) error = copyout(&oss, uap->oss, sizeof(oss)); return (error); } #endif /* COMPAT_43 */ #ifndef _SYS_SYSPROTO_H_ struct sigaltstack_args { stack_t *ss; stack_t *oss; }; #endif /* ARGSUSED */ int sys_sigaltstack(struct thread *td, struct sigaltstack_args *uap) { stack_t ss, oss; int error; if (uap->ss != NULL) { error = copyin(uap->ss, &ss, sizeof(ss)); if (error) return (error); } error = kern_sigaltstack(td, (uap->ss != NULL) ? &ss : NULL, (uap->oss != NULL) ? &oss : NULL); if (error) return (error); if (uap->oss != NULL) error = copyout(&oss, uap->oss, sizeof(stack_t)); return (error); } int kern_sigaltstack(struct thread *td, stack_t *ss, stack_t *oss) { struct proc *p = td->td_proc; int oonstack; oonstack = sigonstack(cpu_getstack(td)); if (oss != NULL) { *oss = td->td_sigstk; oss->ss_flags = (td->td_pflags & TDP_ALTSTACK) ? ((oonstack) ? SS_ONSTACK : 0) : SS_DISABLE; } if (ss != NULL) { if (oonstack) return (EPERM); if ((ss->ss_flags & ~SS_DISABLE) != 0) return (EINVAL); if (!(ss->ss_flags & SS_DISABLE)) { if (ss->ss_size < p->p_sysent->sv_minsigstksz) return (ENOMEM); td->td_sigstk = *ss; td->td_pflags |= TDP_ALTSTACK; } else { td->td_pflags &= ~TDP_ALTSTACK; } } return (0); } struct killpg1_ctx { struct thread *td; ksiginfo_t *ksi; int sig; bool sent; bool found; int ret; }; static void killpg1_sendsig(struct proc *p, bool notself, struct killpg1_ctx *arg) { int err; if (p->p_pid <= 1 || (p->p_flag & P_SYSTEM) != 0 || (notself && p == arg->td->td_proc) || p->p_state == PRS_NEW) return; PROC_LOCK(p); err = p_cansignal(arg->td, p, arg->sig); if (err == 0 && arg->sig != 0) pksignal(p, arg->sig, arg->ksi); PROC_UNLOCK(p); if (err != ESRCH) arg->found = true; if (err == 0) arg->sent = true; else if (arg->ret == 0 && err != ESRCH && err != EPERM) arg->ret = err; } /* * Common code for kill process group/broadcast kill. * cp is calling process. */ static int killpg1(struct thread *td, int sig, int pgid, int all, ksiginfo_t *ksi) { struct proc *p; struct pgrp *pgrp; struct killpg1_ctx arg; arg.td = td; arg.ksi = ksi; arg.sig = sig; arg.sent = false; arg.found = false; arg.ret = 0; if (all) { /* * broadcast */ sx_slock(&allproc_lock); FOREACH_PROC_IN_SYSTEM(p) { killpg1_sendsig(p, true, &arg); } sx_sunlock(&allproc_lock); } else { sx_slock(&proctree_lock); if (pgid == 0) { /* * zero pgid means send to my process group. */ pgrp = td->td_proc->p_pgrp; PGRP_LOCK(pgrp); } else { pgrp = pgfind(pgid); if (pgrp == NULL) { sx_sunlock(&proctree_lock); return (ESRCH); } } sx_sunlock(&proctree_lock); LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { killpg1_sendsig(p, false, &arg); } PGRP_UNLOCK(pgrp); } MPASS(arg.ret != 0 || arg.found || !arg.sent); if (arg.ret == 0 && !arg.sent) arg.ret = arg.found ? EPERM : ESRCH; return (arg.ret); } #ifndef _SYS_SYSPROTO_H_ struct kill_args { int pid; int signum; }; #endif /* ARGSUSED */ int sys_kill(struct thread *td, struct kill_args *uap) { return (kern_kill(td, uap->pid, uap->signum)); } int kern_kill(struct thread *td, pid_t pid, int signum) { ksiginfo_t ksi; struct proc *p; int error; /* * A process in capability mode can send signals only to himself. * The main rationale behind this is that abort(3) is implemented as * kill(getpid(), SIGABRT). */ if (IN_CAPABILITY_MODE(td) && pid != td->td_proc->p_pid) return (ECAPMODE); AUDIT_ARG_SIGNUM(signum); AUDIT_ARG_PID(pid); if ((u_int)signum > _SIG_MAXSIG) return (EINVAL); ksiginfo_init(&ksi); ksi.ksi_signo = signum; ksi.ksi_code = SI_USER; ksi.ksi_pid = td->td_proc->p_pid; ksi.ksi_uid = td->td_ucred->cr_ruid; if (pid > 0) { /* kill single process */ if ((p = pfind_any(pid)) == NULL) return (ESRCH); AUDIT_ARG_PROCESS(p); error = p_cansignal(td, p, signum); if (error == 0 && signum) pksignal(p, signum, &ksi); PROC_UNLOCK(p); return (error); } switch (pid) { case -1: /* broadcast signal */ return (killpg1(td, signum, 0, 1, &ksi)); case 0: /* signal own process group */ return (killpg1(td, signum, 0, 0, &ksi)); default: /* negative explicit process group */ return (killpg1(td, signum, -pid, 0, &ksi)); } /* NOTREACHED */ } int sys_pdkill(struct thread *td, struct pdkill_args *uap) { struct proc *p; int error; AUDIT_ARG_SIGNUM(uap->signum); AUDIT_ARG_FD(uap->fd); if ((u_int)uap->signum > _SIG_MAXSIG) return (EINVAL); error = procdesc_find(td, uap->fd, &cap_pdkill_rights, &p); if (error) return (error); AUDIT_ARG_PROCESS(p); error = p_cansignal(td, p, uap->signum); if (error == 0 && uap->signum) kern_psignal(p, uap->signum); PROC_UNLOCK(p); return (error); } #if defined(COMPAT_43) #ifndef _SYS_SYSPROTO_H_ struct okillpg_args { int pgid; int signum; }; #endif /* ARGSUSED */ int okillpg(struct thread *td, struct okillpg_args *uap) { ksiginfo_t ksi; AUDIT_ARG_SIGNUM(uap->signum); AUDIT_ARG_PID(uap->pgid); if ((u_int)uap->signum > _SIG_MAXSIG) return (EINVAL); ksiginfo_init(&ksi); ksi.ksi_signo = uap->signum; ksi.ksi_code = SI_USER; ksi.ksi_pid = td->td_proc->p_pid; ksi.ksi_uid = td->td_ucred->cr_ruid; return (killpg1(td, uap->signum, uap->pgid, 0, &ksi)); } #endif /* COMPAT_43 */ #ifndef _SYS_SYSPROTO_H_ struct sigqueue_args { pid_t pid; int signum; /* union sigval */ void *value; }; #endif int sys_sigqueue(struct thread *td, struct sigqueue_args *uap) { union sigval sv; sv.sival_ptr = uap->value; return (kern_sigqueue(td, uap->pid, uap->signum, &sv)); } int kern_sigqueue(struct thread *td, pid_t pid, int signum, union sigval *value) { ksiginfo_t ksi; struct proc *p; int error; if ((u_int)signum > _SIG_MAXSIG) return (EINVAL); /* * Specification says sigqueue can only send signal to * single process. */ if (pid <= 0) return (EINVAL); if ((p = pfind_any(pid)) == NULL) return (ESRCH); error = p_cansignal(td, p, signum); if (error == 0 && signum != 0) { ksiginfo_init(&ksi); ksi.ksi_flags = KSI_SIGQ; ksi.ksi_signo = signum; ksi.ksi_code = SI_QUEUE; ksi.ksi_pid = td->td_proc->p_pid; ksi.ksi_uid = td->td_ucred->cr_ruid; ksi.ksi_value = *value; error = pksignal(p, ksi.ksi_signo, &ksi); } PROC_UNLOCK(p); return (error); } /* * Send a signal to a process group. */ void gsignal(int pgid, int sig, ksiginfo_t *ksi) { struct pgrp *pgrp; if (pgid != 0) { sx_slock(&proctree_lock); pgrp = pgfind(pgid); sx_sunlock(&proctree_lock); if (pgrp != NULL) { pgsignal(pgrp, sig, 0, ksi); PGRP_UNLOCK(pgrp); } } } /* * 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) { struct proc *p; if (pgrp) { PGRP_LOCK_ASSERT(pgrp, MA_OWNED); LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { PROC_LOCK(p); if (p->p_state == PRS_NORMAL && (checkctty == 0 || p->p_flag & P_CONTROLT)) pksignal(p, sig, ksi); PROC_UNLOCK(p); } } } /* * Recalculate the signal mask and reset the signal disposition after * usermode frame for delivery is formed. Should be called after * mach-specific routine, because sysent->sv_sendsig() needs correct * ps_siginfo and signal mask. */ static void postsig_done(int sig, struct thread *td, struct sigacts *ps) { sigset_t mask; mtx_assert(&ps->ps_mtx, MA_OWNED); td->td_ru.ru_nsignals++; mask = ps->ps_catchmask[_SIG_IDX(sig)]; if (!SIGISMEMBER(ps->ps_signodefer, sig)) SIGADDSET(mask, sig); kern_sigprocmask(td, SIG_BLOCK, &mask, NULL, SIGPROCMASK_PROC_LOCKED | SIGPROCMASK_PS_LOCKED); if (SIGISMEMBER(ps->ps_sigreset, sig)) sigdflt(ps, sig); } /* * Send a signal caused by a trap to the current thread. If it will be * caught immediately, deliver it with correct code. Otherwise, post it * normally. */ void trapsignal(struct thread *td, ksiginfo_t *ksi) { struct sigacts *ps; struct proc *p; sigset_t sigmask; int sig; p = td->td_proc; sig = ksi->ksi_signo; KASSERT(_SIG_VALID(sig), ("invalid signal")); sigfastblock_fetch(td); PROC_LOCK(p); ps = p->p_sigacts; mtx_lock(&ps->ps_mtx); sigmask = td->td_sigmask; if (td->td_sigblock_val != 0) SIGSETOR(sigmask, fastblock_mask); if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(ps->ps_sigcatch, sig) && !SIGISMEMBER(sigmask, sig)) { #ifdef KTRACE if (KTRPOINT(curthread, KTR_PSIG)) ktrpsig(sig, ps->ps_sigact[_SIG_IDX(sig)], &td->td_sigmask, ksi->ksi_code); #endif (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], ksi, &td->td_sigmask); postsig_done(sig, td, ps); mtx_unlock(&ps->ps_mtx); } else { /* * Avoid a possible infinite loop if the thread * masking the signal or process is ignoring the * signal. */ if (kern_forcesigexit && (SIGISMEMBER(sigmask, sig) || ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN)) { SIGDELSET(td->td_sigmask, sig); SIGDELSET(ps->ps_sigcatch, sig); SIGDELSET(ps->ps_sigignore, sig); ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; td->td_pflags &= ~TDP_SIGFASTBLOCK; td->td_sigblock_val = 0; } mtx_unlock(&ps->ps_mtx); p->p_sig = sig; /* XXX to verify code */ tdsendsignal(p, td, sig, ksi); } PROC_UNLOCK(p); } static struct thread * sigtd(struct proc *p, int sig, bool fast_sigblock) { struct thread *td, *signal_td; PROC_LOCK_ASSERT(p, MA_OWNED); MPASS(!fast_sigblock || p == curproc); /* * Check if current thread can handle the signal without * switching context to another thread. */ if (curproc == p && !SIGISMEMBER(curthread->td_sigmask, sig) && (!fast_sigblock || curthread->td_sigblock_val == 0)) return (curthread); signal_td = NULL; FOREACH_THREAD_IN_PROC(p, td) { if (!SIGISMEMBER(td->td_sigmask, sig) && (!fast_sigblock || td != curthread || td->td_sigblock_val == 0)) { signal_td = td; break; } } if (signal_td == NULL) signal_td = FIRST_THREAD_IN_PROC(p); return (signal_td); } /* * 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. * * NB: This function may be entered from the debugger via the "kill" DDB * command. There is little that can be done to mitigate the possibly messy * side effects of this unwise possibility. */ void kern_psignal(struct proc *p, int sig) { ksiginfo_t ksi; ksiginfo_init(&ksi); ksi.ksi_signo = sig; ksi.ksi_code = SI_KERNEL; (void) tdsendsignal(p, NULL, sig, &ksi); } int pksignal(struct proc *p, int sig, ksiginfo_t *ksi) { return (tdsendsignal(p, NULL, sig, ksi)); } /* Utility function for finding a thread to send signal event to. */ int sigev_findtd(struct proc *p, struct sigevent *sigev, struct thread **ttd) { struct thread *td; if (sigev->sigev_notify == SIGEV_THREAD_ID) { td = tdfind(sigev->sigev_notify_thread_id, p->p_pid); if (td == NULL) return (ESRCH); *ttd = td; } else { *ttd = NULL; PROC_LOCK(p); } return (0); } void tdsignal(struct thread *td, int sig) { ksiginfo_t ksi; ksiginfo_init(&ksi); ksi.ksi_signo = sig; ksi.ksi_code = SI_KERNEL; (void) tdsendsignal(td->td_proc, td, sig, &ksi); } void tdksignal(struct thread *td, int sig, ksiginfo_t *ksi) { (void) tdsendsignal(td->td_proc, td, sig, ksi); } static int sig_sleepq_abort(struct thread *td, int intrval) { THREAD_LOCK_ASSERT(td, MA_OWNED); if (intrval == 0 && (td->td_flags & TDF_SIGWAIT) == 0) { thread_unlock(td); return (0); } return (sleepq_abort(td, intrval)); } int tdsendsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi) { sig_t action; sigqueue_t *sigqueue; int prop; struct sigacts *ps; int intrval; int ret = 0; int wakeup_swapper; MPASS(td == NULL || p == td->td_proc); PROC_LOCK_ASSERT(p, MA_OWNED); if (!_SIG_VALID(sig)) panic("%s(): invalid signal %d", __func__, sig); KASSERT(ksi == NULL || !KSI_ONQ(ksi), ("%s: ksi on queue", __func__)); /* * IEEE Std 1003.1-2001: return success when killing a zombie. */ if (p->p_state == PRS_ZOMBIE) { if (ksi && (ksi->ksi_flags & KSI_INS)) ksiginfo_tryfree(ksi); return (ret); } ps = p->p_sigacts; KNOTE_LOCKED(p->p_klist, NOTE_SIGNAL | sig); prop = sigprop(sig); if (td == NULL) { td = sigtd(p, sig, false); sigqueue = &p->p_sigqueue; } else sigqueue = &td->td_sigqueue; SDT_PROBE3(proc, , , signal__send, td, p, sig); /* * If the signal is being ignored, then we forget about it * immediately, except when the target process executes * sigwait(). (Note: we don't set SIGCONT in ps_sigignore, * and if it is set to SIG_IGN, action will be SIG_DFL here.) */ mtx_lock(&ps->ps_mtx); if (SIGISMEMBER(ps->ps_sigignore, sig)) { if (kern_sig_discard_ign && (p->p_sysent->sv_flags & SV_SIG_DISCIGN) == 0) { SDT_PROBE3(proc, , , signal__discard, td, p, sig); mtx_unlock(&ps->ps_mtx); if (ksi && (ksi->ksi_flags & KSI_INS)) ksiginfo_tryfree(ksi); return (ret); } else { action = SIG_CATCH; intrval = 0; } } else { if (SIGISMEMBER(td->td_sigmask, sig)) action = SIG_HOLD; else if (SIGISMEMBER(ps->ps_sigcatch, sig)) action = SIG_CATCH; else action = SIG_DFL; if (SIGISMEMBER(ps->ps_sigintr, sig)) intrval = EINTR; else intrval = ERESTART; } mtx_unlock(&ps->ps_mtx); if (prop & SIGPROP_CONT) sigqueue_delete_stopmask_proc(p); else if (prop & SIGPROP_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 & SIGPROP_TTYSTOP) != 0 && (p->p_pgrp->pg_flags & PGRP_ORPHANED) != 0 && action == SIG_DFL) { if (ksi && (ksi->ksi_flags & KSI_INS)) ksiginfo_tryfree(ksi); return (ret); } sigqueue_delete_proc(p, SIGCONT); if (p->p_flag & P_CONTINUED) { p->p_flag &= ~P_CONTINUED; PROC_LOCK(p->p_pptr); sigqueue_take(p->p_ksi); PROC_UNLOCK(p->p_pptr); } } ret = sigqueue_add(sigqueue, sig, ksi); if (ret != 0) return (ret); signotify(td); /* * Defer further processing for signals which are held, * except that stopped processes must be continued by SIGCONT. */ if (action == SIG_HOLD && !((prop & SIGPROP_CONT) && (p->p_flag & P_STOPPED_SIG))) return (ret); wakeup_swapper = 0; /* * Some signals have a process-wide effect and a per-thread * component. Most processing occurs when the process next * tries to cross the user boundary, however there are some * times when processing needs to be done immediately, such as * waking up threads so that they can cross the user boundary. * We try to do the per-process part here. */ if (P_SHOULDSTOP(p)) { KASSERT(!(p->p_flag & P_WEXIT), ("signal to stopped but exiting process")); if (sig == SIGKILL) { /* * If traced process is already stopped, * then no further action is necessary. */ if (p->p_flag & P_TRACED) goto out; /* * SIGKILL sets process running. * It will die elsewhere. * All threads must be restarted. */ p->p_flag &= ~P_STOPPED_SIG; goto runfast; } if (prop & SIGPROP_CONT) { /* * If traced process is already stopped, * then no further action is necessary. */ if (p->p_flag & P_TRACED) goto out; /* * If SIGCONT is default (or ignored), we continue the * process but don't leave the signal in sigqueue as * it has no further action. If SIGCONT is held, we * continue the process and leave the signal in * sigqueue. If the process catches SIGCONT, let it * handle the signal itself. If it isn't waiting on * an event, it goes back to run state. * Otherwise, process goes back to sleep state. */ p->p_flag &= ~P_STOPPED_SIG; PROC_SLOCK(p); if (p->p_numthreads == p->p_suspcount) { PROC_SUNLOCK(p); p->p_flag |= P_CONTINUED; p->p_xsig = SIGCONT; PROC_LOCK(p->p_pptr); childproc_continued(p); PROC_UNLOCK(p->p_pptr); PROC_SLOCK(p); } if (action == SIG_DFL) { thread_unsuspend(p); PROC_SUNLOCK(p); sigqueue_delete(sigqueue, sig); goto out_cont; } if (action == SIG_CATCH) { /* * The process wants to catch it so it needs * to run at least one thread, but which one? */ PROC_SUNLOCK(p); goto runfast; } /* * The signal is not ignored or caught. */ thread_unsuspend(p); PROC_SUNLOCK(p); goto out_cont; } if (prop & SIGPROP_STOP) { /* * If traced process is already stopped, * then no further action is necessary. */ if (p->p_flag & P_TRACED) goto out; /* * Already stopped, don't need to stop again * (If we did the shell could get confused). * Just make sure the signal STOP bit set. */ p->p_flag |= P_STOPPED_SIG; sigqueue_delete(sigqueue, sig); goto out; } /* * All other kinds of signals: * If a thread is sleeping interruptibly, simulate a * wakeup so that when it is continued it will be made * runnable and can look at the signal. However, don't make * the PROCESS runnable, leave it stopped. * It may run a bit until it hits a thread_suspend_check(). */ PROC_SLOCK(p); thread_lock(td); if (TD_CAN_ABORT(td)) wakeup_swapper = sig_sleepq_abort(td, intrval); else thread_unlock(td); PROC_SUNLOCK(p); goto out; /* * Mutexes are short lived. Threads waiting on them will * hit thread_suspend_check() soon. */ } else if (p->p_state == PRS_NORMAL) { if (p->p_flag & P_TRACED || action == SIG_CATCH) { tdsigwakeup(td, sig, action, intrval); goto out; } MPASS(action == SIG_DFL); if (prop & SIGPROP_STOP) { if (p->p_flag & (P_PPWAIT|P_WEXIT)) goto out; p->p_flag |= P_STOPPED_SIG; p->p_xsig = sig; PROC_SLOCK(p); wakeup_swapper = sig_suspend_threads(td, p, 1); if (p->p_numthreads == p->p_suspcount) { /* * only thread sending signal to another * process can reach here, if thread is sending * signal to its process, because thread does * not suspend itself here, p_numthreads * should never be equal to p_suspcount. */ thread_stopped(p); PROC_SUNLOCK(p); sigqueue_delete_proc(p, p->p_xsig); } else PROC_SUNLOCK(p); goto out; } } else { /* Not in "NORMAL" state. discard the signal. */ sigqueue_delete(sigqueue, sig); goto out; } /* * The process is not stopped so we need to apply the signal to all the * running threads. */ runfast: tdsigwakeup(td, sig, action, intrval); PROC_SLOCK(p); thread_unsuspend(p); PROC_SUNLOCK(p); out_cont: itimer_proc_continue(p); kqtimer_proc_continue(p); out: /* If we jump here, proc slock should not be owned. */ PROC_SLOCK_ASSERT(p, MA_NOTOWNED); if (wakeup_swapper) kick_proc0(); return (ret); } /* * The force of a signal has been directed against a single * thread. We need to see what we can do about knocking it * out of any sleep it may be in etc. */ static void tdsigwakeup(struct thread *td, int sig, sig_t action, int intrval) { struct proc *p = td->td_proc; int prop, wakeup_swapper; PROC_LOCK_ASSERT(p, MA_OWNED); prop = sigprop(sig); PROC_SLOCK(p); thread_lock(td); /* * Bring the priority of a thread up if we want it to get * killed in this lifetime. Be careful to avoid bumping the * priority of the idle thread, since we still allow to signal * kernel processes. */ if (action == SIG_DFL && (prop & SIGPROP_KILL) != 0 && td->td_priority > PUSER && !TD_IS_IDLETHREAD(td)) sched_prio(td, PUSER); if (TD_ON_SLEEPQ(td)) { /* * If thread is sleeping uninterruptibly * we can't interrupt the sleep... the signal will * be noticed when the process returns through * trap() or syscall(). */ if ((td->td_flags & TDF_SINTR) == 0) goto out; /* * If SIGCONT is default (or ignored) and process is * asleep, we are finished; the process should not * be awakened. */ if ((prop & SIGPROP_CONT) && action == SIG_DFL) { thread_unlock(td); PROC_SUNLOCK(p); sigqueue_delete(&p->p_sigqueue, sig); /* * It may be on either list in this state. * Remove from both for now. */ sigqueue_delete(&td->td_sigqueue, sig); return; } /* * Don't awaken a sleeping thread for SIGSTOP if the * STOP signal is deferred. */ if ((prop & SIGPROP_STOP) != 0 && (td->td_flags & (TDF_SBDRY | TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY) goto out; /* * Give low priority threads a better chance to run. */ if (td->td_priority > PUSER && !TD_IS_IDLETHREAD(td)) sched_prio(td, PUSER); wakeup_swapper = sig_sleepq_abort(td, intrval); PROC_SUNLOCK(p); if (wakeup_swapper) kick_proc0(); return; } /* * Other states do nothing with the signal immediately, * other than kicking ourselves if we are running. * It will either never be noticed, or noticed very soon. */ #ifdef SMP if (TD_IS_RUNNING(td) && td != curthread) forward_signal(td); #endif out: PROC_SUNLOCK(p); thread_unlock(td); } static void ptrace_coredump(struct thread *td) { struct proc *p; struct thr_coredump_req *tcq; void *rl_cookie; MPASS(td == curthread); p = td->td_proc; PROC_LOCK_ASSERT(p, MA_OWNED); if ((td->td_dbgflags & TDB_COREDUMPRQ) == 0) return; KASSERT((p->p_flag & P_STOPPED_TRACE) != 0, ("not stopped")); tcq = td->td_coredump; KASSERT(tcq != NULL, ("td_coredump is NULL")); if (p->p_sysent->sv_coredump == NULL) { tcq->tc_error = ENOSYS; goto wake; } PROC_UNLOCK(p); rl_cookie = vn_rangelock_wlock(tcq->tc_vp, 0, OFF_MAX); tcq->tc_error = p->p_sysent->sv_coredump(td, tcq->tc_vp, tcq->tc_limit, tcq->tc_flags); vn_rangelock_unlock(tcq->tc_vp, rl_cookie); PROC_LOCK(p); wake: td->td_dbgflags &= ~TDB_COREDUMPRQ; td->td_coredump = NULL; wakeup(p); } static int sig_suspend_threads(struct thread *td, struct proc *p, int sending) { struct thread *td2; int wakeup_swapper; PROC_LOCK_ASSERT(p, MA_OWNED); PROC_SLOCK_ASSERT(p, MA_OWNED); MPASS(sending || td == curthread); wakeup_swapper = 0; FOREACH_THREAD_IN_PROC(p, td2) { thread_lock(td2); ast_sched_locked(td2, TDA_SUSPEND); if ((TD_IS_SLEEPING(td2) || TD_IS_SWAPPED(td2)) && (td2->td_flags & TDF_SINTR)) { if (td2->td_flags & TDF_SBDRY) { /* * Once a thread is asleep with * TDF_SBDRY and without TDF_SERESTART * or TDF_SEINTR set, it should never * become suspended due to this check. */ KASSERT(!TD_IS_SUSPENDED(td2), ("thread with deferred stops suspended")); if (TD_SBDRY_INTR(td2)) { wakeup_swapper |= sleepq_abort(td2, TD_SBDRY_ERRNO(td2)); continue; } } else if (!TD_IS_SUSPENDED(td2)) thread_suspend_one(td2); } else if (!TD_IS_SUSPENDED(td2)) { if (sending || td != td2) ast_sched_locked(td2, TDA_AST); #ifdef SMP if (TD_IS_RUNNING(td2) && td2 != td) forward_signal(td2); #endif } thread_unlock(td2); } return (wakeup_swapper); } /* * Stop the process for an event deemed interesting to the debugger. If si is * non-NULL, this is a signal exchange; the new signal requested by the * debugger will be returned for handling. If si is NULL, this is some other * type of interesting event. The debugger may request a signal be delivered in * that case as well, however it will be deferred until it can be handled. */ int ptracestop(struct thread *td, int sig, ksiginfo_t *si) { struct proc *p = td->td_proc; struct thread *td2; ksiginfo_t ksi; PROC_LOCK_ASSERT(p, MA_OWNED); KASSERT(!(p->p_flag & P_WEXIT), ("Stopping exiting process")); WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, &p->p_mtx.lock_object, "Stopping for traced signal"); td->td_xsig = sig; if (si == NULL || (si->ksi_flags & KSI_PTRACE) == 0) { td->td_dbgflags |= TDB_XSIG; CTR4(KTR_PTRACE, "ptracestop: tid %d (pid %d) flags %#x sig %d", td->td_tid, p->p_pid, td->td_dbgflags, sig); PROC_SLOCK(p); while ((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_XSIG)) { if (P_KILLED(p)) { /* * Ensure that, if we've been PT_KILLed, the * exit status reflects that. Another thread * may also be in ptracestop(), having just * received the SIGKILL, but this thread was * unsuspended first. */ td->td_dbgflags &= ~TDB_XSIG; td->td_xsig = SIGKILL; p->p_ptevents = 0; break; } if (p->p_flag & P_SINGLE_EXIT && !(td->td_dbgflags & TDB_EXIT)) { /* * Ignore ptrace stops except for thread exit * events when the process exits. */ td->td_dbgflags &= ~TDB_XSIG; PROC_SUNLOCK(p); return (0); } /* * Make wait(2) work. Ensure that right after the * attach, the thread which was decided to become the * leader of attach gets reported to the waiter. * Otherwise, just avoid overwriting another thread's * assignment to p_xthread. If another thread has * already set p_xthread, the current thread will get * a chance to report itself upon the next iteration. */ if ((td->td_dbgflags & TDB_FSTP) != 0 || ((p->p_flag2 & P2_PTRACE_FSTP) == 0 && p->p_xthread == NULL)) { p->p_xsig = sig; p->p_xthread = td; /* * If we are on sleepqueue already, * let sleepqueue code decide if it * needs to go sleep after attach. */ if (td->td_wchan == NULL) td->td_dbgflags &= ~TDB_FSTP; p->p_flag2 &= ~P2_PTRACE_FSTP; p->p_flag |= P_STOPPED_SIG | P_STOPPED_TRACE; sig_suspend_threads(td, p, 0); } if ((td->td_dbgflags & TDB_STOPATFORK) != 0) { td->td_dbgflags &= ~TDB_STOPATFORK; } stopme: td->td_dbgflags |= TDB_SSWITCH; thread_suspend_switch(td, p); td->td_dbgflags &= ~TDB_SSWITCH; if ((td->td_dbgflags & TDB_COREDUMPRQ) != 0) { PROC_SUNLOCK(p); ptrace_coredump(td); PROC_SLOCK(p); goto stopme; } if (p->p_xthread == td) p->p_xthread = NULL; if (!(p->p_flag & P_TRACED)) break; if (td->td_dbgflags & TDB_SUSPEND) { if (p->p_flag & P_SINGLE_EXIT) break; goto stopme; } } PROC_SUNLOCK(p); } if (si != NULL && sig == td->td_xsig) { /* Parent wants us to take the original signal unchanged. */ si->ksi_flags |= KSI_HEAD; if (sigqueue_add(&td->td_sigqueue, sig, si) != 0) si->ksi_signo = 0; } else if (td->td_xsig != 0) { /* * If parent wants us to take a new signal, then it will leave * it in td->td_xsig; otherwise we just look for signals again. */ ksiginfo_init(&ksi); ksi.ksi_signo = td->td_xsig; ksi.ksi_flags |= KSI_PTRACE; td2 = sigtd(p, td->td_xsig, false); tdsendsignal(p, td2, td->td_xsig, &ksi); if (td != td2) return (0); } return (td->td_xsig); } static void reschedule_signals(struct proc *p, sigset_t block, int flags) { struct sigacts *ps; struct thread *td; int sig; bool fastblk, pslocked; PROC_LOCK_ASSERT(p, MA_OWNED); ps = p->p_sigacts; pslocked = (flags & SIGPROCMASK_PS_LOCKED) != 0; mtx_assert(&ps->ps_mtx, pslocked ? MA_OWNED : MA_NOTOWNED); if (SIGISEMPTY(p->p_siglist)) return; SIGSETAND(block, p->p_siglist); fastblk = (flags & SIGPROCMASK_FASTBLK) != 0; SIG_FOREACH(sig, &block) { td = sigtd(p, sig, fastblk); /* * If sigtd() selected us despite sigfastblock is * blocking, do not activate AST or wake us, to avoid * loop in AST handler. */ if (fastblk && td == curthread) continue; signotify(td); if (!pslocked) mtx_lock(&ps->ps_mtx); if (p->p_flag & P_TRACED || (SIGISMEMBER(ps->ps_sigcatch, sig) && !SIGISMEMBER(td->td_sigmask, sig))) { tdsigwakeup(td, sig, SIG_CATCH, (SIGISMEMBER(ps->ps_sigintr, sig) ? EINTR : ERESTART)); } if (!pslocked) mtx_unlock(&ps->ps_mtx); } } void tdsigcleanup(struct thread *td) { struct proc *p; sigset_t unblocked; p = td->td_proc; PROC_LOCK_ASSERT(p, MA_OWNED); sigqueue_flush(&td->td_sigqueue); if (p->p_numthreads == 1) return; /* * Since we cannot handle signals, notify signal post code * about this by filling the sigmask. * * Also, if needed, wake up thread(s) that do not block the * same signals as the exiting thread, since the thread might * have been selected for delivery and woken up. */ SIGFILLSET(unblocked); SIGSETNAND(unblocked, td->td_sigmask); SIGFILLSET(td->td_sigmask); reschedule_signals(p, unblocked, 0); } static int sigdeferstop_curr_flags(int cflags) { MPASS((cflags & (TDF_SEINTR | TDF_SERESTART)) == 0 || (cflags & TDF_SBDRY) != 0); return (cflags & (TDF_SBDRY | TDF_SEINTR | TDF_SERESTART)); } /* * Defer the delivery of SIGSTOP for the current thread, according to * the requested mode. Returns previous flags, which must be restored * by sigallowstop(). * * TDF_SBDRY, TDF_SEINTR, and TDF_SERESTART flags are only set and * cleared by the current thread, which allow the lock-less read-only * accesses below. */ int sigdeferstop_impl(int mode) { struct thread *td; int cflags, nflags; td = curthread; cflags = sigdeferstop_curr_flags(td->td_flags); switch (mode) { case SIGDEFERSTOP_NOP: nflags = cflags; break; case SIGDEFERSTOP_OFF: nflags = 0; break; case SIGDEFERSTOP_SILENT: nflags = (cflags | TDF_SBDRY) & ~(TDF_SEINTR | TDF_SERESTART); break; case SIGDEFERSTOP_EINTR: nflags = (cflags | TDF_SBDRY | TDF_SEINTR) & ~TDF_SERESTART; break; case SIGDEFERSTOP_ERESTART: nflags = (cflags | TDF_SBDRY | TDF_SERESTART) & ~TDF_SEINTR; break; default: panic("sigdeferstop: invalid mode %x", mode); break; } if (cflags == nflags) return (SIGDEFERSTOP_VAL_NCHG); thread_lock(td); td->td_flags = (td->td_flags & ~cflags) | nflags; thread_unlock(td); return (cflags); } /* * Restores the STOP handling mode, typically permitting the delivery * of SIGSTOP for the current thread. This does not immediately * suspend if a stop was posted. Instead, the thread will suspend * either via ast() or a subsequent interruptible sleep. */ void sigallowstop_impl(int prev) { struct thread *td; int cflags; KASSERT(prev != SIGDEFERSTOP_VAL_NCHG, ("failed sigallowstop")); KASSERT((prev & ~(TDF_SBDRY | TDF_SEINTR | TDF_SERESTART)) == 0, ("sigallowstop: incorrect previous mode %x", prev)); td = curthread; cflags = sigdeferstop_curr_flags(td->td_flags); if (cflags != prev) { thread_lock(td); td->td_flags = (td->td_flags & ~cflags) | prev; thread_unlock(td); } } enum sigstatus { SIGSTATUS_HANDLE, SIGSTATUS_HANDLED, SIGSTATUS_IGNORE, SIGSTATUS_SBDRY_STOP, }; /* * The thread has signal "sig" pending. Figure out what to do with it: * * _HANDLE -> the caller should handle the signal * _HANDLED -> handled internally, reload pending signal set * _IGNORE -> ignored, remove from the set of pending signals and try the * next pending signal * _SBDRY_STOP -> the signal should stop the thread but this is not * permitted in the current context */ static enum sigstatus sigprocess(struct thread *td, int sig) { struct proc *p; struct sigacts *ps; struct sigqueue *queue; ksiginfo_t ksi; int prop; KASSERT(_SIG_VALID(sig), ("%s: invalid signal %d", __func__, sig)); p = td->td_proc; ps = p->p_sigacts; mtx_assert(&ps->ps_mtx, MA_OWNED); PROC_LOCK_ASSERT(p, MA_OWNED); /* * We should allow pending but ignored signals below * if there is sigwait() active, or P_TRACED was * on when they were posted. */ if (SIGISMEMBER(ps->ps_sigignore, sig) && (p->p_flag & P_TRACED) == 0 && (td->td_flags & TDF_SIGWAIT) == 0) { return (SIGSTATUS_IGNORE); } /* * If the process is going to single-thread mode to prepare * for exit, there is no sense in delivering any signal * to usermode. Another important consequence is that * msleep(..., PCATCH, ...) now is only interruptible by a * suspend request. */ if ((p->p_flag2 & P2_WEXIT) != 0) return (SIGSTATUS_IGNORE); if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED) { /* * If traced, always stop. * Remove old signal from queue before the stop. * XXX shrug off debugger, it causes siginfo to * be thrown away. */ queue = &td->td_sigqueue; ksiginfo_init(&ksi); if (sigqueue_get(queue, sig, &ksi) == 0) { queue = &p->p_sigqueue; sigqueue_get(queue, sig, &ksi); } td->td_si = ksi.ksi_info; mtx_unlock(&ps->ps_mtx); sig = ptracestop(td, sig, &ksi); mtx_lock(&ps->ps_mtx); td->td_si.si_signo = 0; /* * Keep looking if the debugger discarded or * replaced the signal. */ if (sig == 0) return (SIGSTATUS_HANDLED); /* * If the signal became masked, re-queue it. */ if (SIGISMEMBER(td->td_sigmask, sig)) { ksi.ksi_flags |= KSI_HEAD; sigqueue_add(&p->p_sigqueue, sig, &ksi); return (SIGSTATUS_HANDLED); } /* * If the traced bit got turned off, requeue the signal and * reload the set of pending signals. This ensures that p_sig* * and p_sigact are consistent. */ if ((p->p_flag & P_TRACED) == 0) { if ((ksi.ksi_flags & KSI_PTRACE) == 0) { ksi.ksi_flags |= KSI_HEAD; sigqueue_add(queue, sig, &ksi); } return (SIGSTATUS_HANDLED); } } /* * Decide whether the signal should be returned. * Return the signal's number, or fall through * to clear it from the pending mask. */ switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { case (intptr_t)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 %lu) got signal %d\n", (u_long)p->p_pid, sig); #endif return (SIGSTATUS_IGNORE); } /* * If there is a pending stop signal to process with * default action, stop here, then clear the signal. * Traced or exiting processes should ignore stops. * Additionally, a member of an orphaned process group * should ignore tty stops. */ prop = sigprop(sig); if (prop & SIGPROP_STOP) { mtx_unlock(&ps->ps_mtx); if ((p->p_flag & (P_TRACED | P_WEXIT | P_SINGLE_EXIT)) != 0 || ((p->p_pgrp-> pg_flags & PGRP_ORPHANED) != 0 && (prop & SIGPROP_TTYSTOP) != 0)) { mtx_lock(&ps->ps_mtx); return (SIGSTATUS_IGNORE); } if (TD_SBDRY_INTR(td)) { KASSERT((td->td_flags & TDF_SBDRY) != 0, ("lost TDF_SBDRY")); mtx_lock(&ps->ps_mtx); return (SIGSTATUS_SBDRY_STOP); } WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, &p->p_mtx.lock_object, "Catching SIGSTOP"); sigqueue_delete(&td->td_sigqueue, sig); sigqueue_delete(&p->p_sigqueue, sig); p->p_flag |= P_STOPPED_SIG; p->p_xsig = sig; PROC_SLOCK(p); sig_suspend_threads(td, p, 0); thread_suspend_switch(td, p); PROC_SUNLOCK(p); mtx_lock(&ps->ps_mtx); return (SIGSTATUS_HANDLED); } else if ((prop & SIGPROP_IGNORE) != 0 && (td->td_flags & TDF_SIGWAIT) == 0) { /* * Default action is to ignore; drop it if * not in kern_sigtimedwait(). */ return (SIGSTATUS_IGNORE); } else { return (SIGSTATUS_HANDLE); } case (intptr_t)SIG_IGN: if ((td->td_flags & TDF_SIGWAIT) == 0) return (SIGSTATUS_IGNORE); else return (SIGSTATUS_HANDLE); default: /* * This signal has an action, let postsig() process it. */ return (SIGSTATUS_HANDLE); } } /* * 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 cursig.) The normal call * sequence is * * while (sig = cursig(curthread)) * postsig(sig); */ static int issignal(struct thread *td) { struct proc *p; sigset_t sigpending; int sig; p = td->td_proc; PROC_LOCK_ASSERT(p, MA_OWNED); for (;;) { sigpending = td->td_sigqueue.sq_signals; SIGSETOR(sigpending, p->p_sigqueue.sq_signals); SIGSETNAND(sigpending, td->td_sigmask); if ((p->p_flag & P_PPWAIT) != 0 || (td->td_flags & (TDF_SBDRY | TDF_SERESTART | TDF_SEINTR)) == TDF_SBDRY) SIG_STOPSIGMASK(sigpending); if (SIGISEMPTY(sigpending)) /* no signal to send */ return (0); /* * Do fast sigblock if requested by usermode. Since * we do know that there was a signal pending at this * point, set the FAST_SIGBLOCK_PEND as indicator for * usermode to perform a dummy call to * FAST_SIGBLOCK_UNBLOCK, which causes immediate * delivery of postponed pending signal. */ if ((td->td_pflags & TDP_SIGFASTBLOCK) != 0) { if (td->td_sigblock_val != 0) SIGSETNAND(sigpending, fastblock_mask); if (SIGISEMPTY(sigpending)) { td->td_pflags |= TDP_SIGFASTPENDING; return (0); } } if ((p->p_flag & (P_TRACED | P_PPTRACE)) == P_TRACED && (p->p_flag2 & P2_PTRACE_FSTP) != 0 && SIGISMEMBER(sigpending, SIGSTOP)) { /* * If debugger just attached, always consume * SIGSTOP from ptrace(PT_ATTACH) first, to * execute the debugger attach ritual in * order. */ td->td_dbgflags |= TDB_FSTP; SIGEMPTYSET(sigpending); SIGADDSET(sigpending, SIGSTOP); } SIG_FOREACH(sig, &sigpending) { switch (sigprocess(td, sig)) { case SIGSTATUS_HANDLE: return (sig); case SIGSTATUS_HANDLED: goto next; case SIGSTATUS_IGNORE: sigqueue_delete(&td->td_sigqueue, sig); sigqueue_delete(&p->p_sigqueue, sig); break; case SIGSTATUS_SBDRY_STOP: return (-1); } } next:; } } void thread_stopped(struct proc *p) { int n; PROC_LOCK_ASSERT(p, MA_OWNED); PROC_SLOCK_ASSERT(p, MA_OWNED); n = p->p_suspcount; if (p == curproc) n++; if ((p->p_flag & P_STOPPED_SIG) && (n == p->p_numthreads)) { PROC_SUNLOCK(p); p->p_flag &= ~P_WAITED; PROC_LOCK(p->p_pptr); childproc_stopped(p, (p->p_flag & P_TRACED) ? CLD_TRAPPED : CLD_STOPPED); PROC_UNLOCK(p->p_pptr); PROC_SLOCK(p); } } /* * Take the action for the specified signal * from the current set of pending signals. */ int postsig(int sig) { struct thread *td; struct proc *p; struct sigacts *ps; sig_t action; ksiginfo_t ksi; sigset_t returnmask; KASSERT(sig != 0, ("postsig")); td = curthread; p = td->td_proc; PROC_LOCK_ASSERT(p, MA_OWNED); ps = p->p_sigacts; mtx_assert(&ps->ps_mtx, MA_OWNED); ksiginfo_init(&ksi); if (sigqueue_get(&td->td_sigqueue, sig, &ksi) == 0 && sigqueue_get(&p->p_sigqueue, sig, &ksi) == 0) return (0); ksi.ksi_signo = sig; if (ksi.ksi_code == SI_TIMER) itimer_accept(p, ksi.ksi_timerid, &ksi); action = ps->ps_sigact[_SIG_IDX(sig)]; #ifdef KTRACE if (KTRPOINT(td, KTR_PSIG)) ktrpsig(sig, action, td->td_pflags & TDP_OLDMASK ? &td->td_oldsigmask : &td->td_sigmask, ksi.ksi_code); #endif if (action == SIG_DFL) { /* * Default action, where the default is to kill * the process. (Other cases were ignored above.) */ mtx_unlock(&ps->ps_mtx); proc_td_siginfo_capture(td, &ksi.ksi_info); sigexit(td, sig); /* NOTREACHED */ } else { /* * If we get here, the signal must be caught. */ KASSERT(action != SIG_IGN, ("postsig action %p", action)); KASSERT(!SIGISMEMBER(td->td_sigmask, sig), ("postsig action: blocked sig %d", sig)); /* * Set the new mask value and also defer further * occurrences of this signal. * * Special case: user has done a sigsuspend. Here the * current mask is not of interest, but rather the * mask from before the sigsuspend is what we want * restored after the signal processing is completed. */ if (td->td_pflags & TDP_OLDMASK) { returnmask = td->td_oldsigmask; td->td_pflags &= ~TDP_OLDMASK; } else returnmask = td->td_sigmask; if (p->p_sig == sig) { p->p_sig = 0; } (*p->p_sysent->sv_sendsig)(action, &ksi, &returnmask); postsig_done(sig, td, ps); } return (1); } int sig_ast_checksusp(struct thread *td) { struct proc *p __diagused; int ret; p = td->td_proc; PROC_LOCK_ASSERT(p, MA_OWNED); if (!td_ast_pending(td, TDA_SUSPEND)) return (0); ret = thread_suspend_check(1); MPASS(ret == 0 || ret == EINTR || ret == ERESTART); return (ret); } int sig_ast_needsigchk(struct thread *td) { struct proc *p; struct sigacts *ps; int ret, sig; p = td->td_proc; PROC_LOCK_ASSERT(p, MA_OWNED); if (!td_ast_pending(td, TDA_SIG)) return (0); ps = p->p_sigacts; mtx_lock(&ps->ps_mtx); sig = cursig(td); if (sig == -1) { mtx_unlock(&ps->ps_mtx); KASSERT((td->td_flags & TDF_SBDRY) != 0, ("lost TDF_SBDRY")); KASSERT(TD_SBDRY_INTR(td), ("lost TDF_SERESTART of TDF_SEINTR")); KASSERT((td->td_flags & (TDF_SEINTR | TDF_SERESTART)) != (TDF_SEINTR | TDF_SERESTART), ("both TDF_SEINTR and TDF_SERESTART")); ret = TD_SBDRY_ERRNO(td); } else if (sig != 0) { ret = SIGISMEMBER(ps->ps_sigintr, sig) ? EINTR : ERESTART; mtx_unlock(&ps->ps_mtx); } else { mtx_unlock(&ps->ps_mtx); ret = 0; } /* * Do not go into sleep if this thread was the ptrace(2) * attach leader. cursig() consumed SIGSTOP from PT_ATTACH, * but we usually act on the signal by interrupting sleep, and * should do that here as well. */ if ((td->td_dbgflags & TDB_FSTP) != 0) { if (ret == 0) ret = EINTR; td->td_dbgflags &= ~TDB_FSTP; } return (ret); } int sig_intr(void) { struct thread *td; struct proc *p; int ret; td = curthread; if (!td_ast_pending(td, TDA_SIG) && !td_ast_pending(td, TDA_SUSPEND)) return (0); p = td->td_proc; PROC_LOCK(p); ret = sig_ast_checksusp(td); if (ret == 0) ret = sig_ast_needsigchk(td); PROC_UNLOCK(p); return (ret); } bool curproc_sigkilled(void) { struct thread *td; struct proc *p; struct sigacts *ps; bool res; td = curthread; if (!td_ast_pending(td, TDA_SIG)) return (false); p = td->td_proc; PROC_LOCK(p); ps = p->p_sigacts; mtx_lock(&ps->ps_mtx); res = SIGISMEMBER(td->td_sigqueue.sq_signals, SIGKILL) || SIGISMEMBER(p->p_sigqueue.sq_signals, SIGKILL); mtx_unlock(&ps->ps_mtx); PROC_UNLOCK(p); return (res); } void proc_wkilled(struct proc *p) { PROC_LOCK_ASSERT(p, MA_OWNED); if ((p->p_flag & P_WKILLED) == 0) { p->p_flag |= P_WKILLED; /* * Notify swapper that there is a process to swap in. * The notification is racy, at worst it would take 10 * seconds for the swapper process to notice. */ if ((p->p_flag & (P_INMEM | P_SWAPPINGIN)) == 0) wakeup(&proc0); } } /* * Kill the current process for stated reason. */ void killproc(struct proc *p, const char *why) { PROC_LOCK_ASSERT(p, MA_OWNED); CTR3(KTR_PROC, "killproc: proc %p (pid %d, %s)", p, p->p_pid, p->p_comm); log(LOG_ERR, "pid %d (%s), jid %d, uid %d, was killed: %s\n", p->p_pid, p->p_comm, p->p_ucred->cr_prison->pr_id, p->p_ucred->cr_uid, why); proc_wkilled(p); kern_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. */ void sigexit(struct thread *td, int sig) { struct proc *p = td->td_proc; PROC_LOCK_ASSERT(p, MA_OWNED); proc_set_p2_wexit(p); p->p_acflag |= AXSIG; /* * We must be single-threading to generate a core dump. This * ensures that the registers in the core file are up-to-date. * Also, the ELF dump handler assumes that the thread list doesn't * change out from under it. * * XXX If another thread attempts to single-thread before us * (e.g. via fork()), we won't get a dump at all. */ if ((sigprop(sig) & SIGPROP_CORE) && thread_single(p, SINGLE_NO_EXIT) == 0) { p->p_sig = sig; /* * Log signals which would cause core dumps * (Log as LOG_INFO to appease those who don't want * these messages.) * XXX : Todo, as well as euid, write out ruid too * Note that coredump() drops proc lock. */ if (coredump(td) == 0) sig |= WCOREFLAG; if (kern_logsigexit) log(LOG_INFO, "pid %d (%s), jid %d, uid %d: exited on " "signal %d%s\n", p->p_pid, p->p_comm, p->p_ucred->cr_prison->pr_id, td->td_ucred->cr_uid, sig &~ WCOREFLAG, sig & WCOREFLAG ? " (core dumped)" : ""); } else PROC_UNLOCK(p); exit1(td, 0, sig); /* NOTREACHED */ } /* * Send queued SIGCHLD to parent when child process's state * is changed. */ static void sigparent(struct proc *p, int reason, int status) { PROC_LOCK_ASSERT(p, MA_OWNED); PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED); if (p->p_ksi != NULL) { p->p_ksi->ksi_signo = SIGCHLD; p->p_ksi->ksi_code = reason; p->p_ksi->ksi_status = status; p->p_ksi->ksi_pid = p->p_pid; p->p_ksi->ksi_uid = p->p_ucred->cr_ruid; if (KSI_ONQ(p->p_ksi)) return; } pksignal(p->p_pptr, SIGCHLD, p->p_ksi); } static void childproc_jobstate(struct proc *p, int reason, int sig) { struct sigacts *ps; PROC_LOCK_ASSERT(p, MA_OWNED); PROC_LOCK_ASSERT(p->p_pptr, MA_OWNED); /* * Wake up parent sleeping in kern_wait(), also send * SIGCHLD to parent, but SIGCHLD does not guarantee * that parent will awake, because parent may masked * the signal. */ p->p_pptr->p_flag |= P_STATCHILD; wakeup(p->p_pptr); ps = p->p_pptr->p_sigacts; mtx_lock(&ps->ps_mtx); if ((ps->ps_flag & PS_NOCLDSTOP) == 0) { mtx_unlock(&ps->ps_mtx); sigparent(p, reason, sig); } else mtx_unlock(&ps->ps_mtx); } void childproc_stopped(struct proc *p, int reason) { childproc_jobstate(p, reason, p->p_xsig); } void childproc_continued(struct proc *p) { childproc_jobstate(p, CLD_CONTINUED, SIGCONT); } void childproc_exited(struct proc *p) { int reason, status; if (WCOREDUMP(p->p_xsig)) { reason = CLD_DUMPED; status = WTERMSIG(p->p_xsig); } else if (WIFSIGNALED(p->p_xsig)) { reason = CLD_KILLED; status = WTERMSIG(p->p_xsig); } else { reason = CLD_EXITED; status = p->p_xexit; } /* * XXX avoid calling wakeup(p->p_pptr), the work is * done in exit1(). */ sigparent(p, reason, status); } #define MAX_NUM_CORE_FILES 100000 #ifndef NUM_CORE_FILES #define NUM_CORE_FILES 5 #endif CTASSERT(NUM_CORE_FILES >= 0 && NUM_CORE_FILES <= MAX_NUM_CORE_FILES); static int num_cores = NUM_CORE_FILES; static int sysctl_debug_num_cores_check (SYSCTL_HANDLER_ARGS) { int error; int new_val; new_val = num_cores; error = sysctl_handle_int(oidp, &new_val, 0, req); if (error != 0 || req->newptr == NULL) return (error); if (new_val > MAX_NUM_CORE_FILES) new_val = MAX_NUM_CORE_FILES; if (new_val < 0) new_val = 0; num_cores = new_val; return (0); } SYSCTL_PROC(_debug, OID_AUTO, ncores, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, sizeof(int), sysctl_debug_num_cores_check, "I", "Maximum number of generated process corefiles while using index format"); #define GZIP_SUFFIX ".gz" #define ZSTD_SUFFIX ".zst" int compress_user_cores = 0; static int sysctl_compress_user_cores(SYSCTL_HANDLER_ARGS) { int error, val; val = compress_user_cores; error = sysctl_handle_int(oidp, &val, 0, req); if (error != 0 || req->newptr == NULL) return (error); if (val != 0 && !compressor_avail(val)) return (EINVAL); compress_user_cores = val; return (error); } SYSCTL_PROC(_kern, OID_AUTO, compress_user_cores, CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_NEEDGIANT, 0, sizeof(int), sysctl_compress_user_cores, "I", "Enable compression of user corefiles (" __XSTRING(COMPRESS_GZIP) " = gzip, " __XSTRING(COMPRESS_ZSTD) " = zstd)"); int compress_user_cores_level = 6; SYSCTL_INT(_kern, OID_AUTO, compress_user_cores_level, CTLFLAG_RWTUN, &compress_user_cores_level, 0, "Corefile compression level"); /* * Protect the access to corefilename[] by allproc_lock. */ #define corefilename_lock allproc_lock static char corefilename[MAXPATHLEN] = {"%N.core"}; TUNABLE_STR("kern.corefile", corefilename, sizeof(corefilename)); static int sysctl_kern_corefile(SYSCTL_HANDLER_ARGS) { int error; sx_xlock(&corefilename_lock); error = sysctl_handle_string(oidp, corefilename, sizeof(corefilename), req); sx_xunlock(&corefilename_lock); return (error); } SYSCTL_PROC(_kern, OID_AUTO, corefile, CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 0, sysctl_kern_corefile, "A", "Process corefile name format string"); static void vnode_close_locked(struct thread *td, struct vnode *vp) { VOP_UNLOCK(vp); vn_close(vp, FWRITE, td->td_ucred, td); } /* * If the core format has a %I in it, then we need to check * for existing corefiles before defining a name. * To do this we iterate over 0..ncores to find a * non-existing core file name to use. If all core files are * already used we choose the oldest one. */ static int corefile_open_last(struct thread *td, char *name, int indexpos, int indexlen, int ncores, struct vnode **vpp) { struct vnode *oldvp, *nextvp, *vp; struct vattr vattr; struct nameidata nd; int error, i, flags, oflags, cmode; char ch; struct timespec lasttime; nextvp = oldvp = NULL; cmode = S_IRUSR | S_IWUSR; oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE | (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0); for (i = 0; i < ncores; i++) { flags = O_CREAT | FWRITE | O_NOFOLLOW; ch = name[indexpos + indexlen]; (void)snprintf(name + indexpos, indexlen + 1, "%.*u", indexlen, i); name[indexpos + indexlen] = ch; NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name); error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred, NULL); if (error != 0) break; vp = nd.ni_vp; NDFREE_PNBUF(&nd); if ((flags & O_CREAT) == O_CREAT) { nextvp = vp; break; } error = VOP_GETATTR(vp, &vattr, td->td_ucred); if (error != 0) { vnode_close_locked(td, vp); break; } if (oldvp == NULL || lasttime.tv_sec > vattr.va_mtime.tv_sec || (lasttime.tv_sec == vattr.va_mtime.tv_sec && lasttime.tv_nsec >= vattr.va_mtime.tv_nsec)) { if (oldvp != NULL) vn_close(oldvp, FWRITE, td->td_ucred, td); oldvp = vp; VOP_UNLOCK(oldvp); lasttime = vattr.va_mtime; } else { vnode_close_locked(td, vp); } } if (oldvp != NULL) { if (nextvp == NULL) { if ((td->td_proc->p_flag & P_SUGID) != 0) { error = EFAULT; vn_close(oldvp, FWRITE, td->td_ucred, td); } else { nextvp = oldvp; error = vn_lock(nextvp, LK_EXCLUSIVE); if (error != 0) { vn_close(nextvp, FWRITE, td->td_ucred, td); nextvp = NULL; } } } else { vn_close(oldvp, FWRITE, td->td_ucred, td); } } if (error != 0) { if (nextvp != NULL) vnode_close_locked(td, oldvp); } else { *vpp = nextvp; } return (error); } /* * corefile_open(comm, uid, pid, td, compress, vpp, namep) * Expand the name described in corefilename, using name, uid, and pid * and open/create core file. * corefilename is a printf-like string, with three format specifiers: * %N name of process ("name") * %P process id (pid) * %U user id (uid) * For example, "%N.core" is the default; they can be disabled completely * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". * This is controlled by the sysctl variable kern.corefile (see above). */ static int corefile_open(const char *comm, uid_t uid, pid_t pid, struct thread *td, int compress, int signum, struct vnode **vpp, char **namep) { struct sbuf sb; struct nameidata nd; const char *format; char *hostname, *name; int cmode, error, flags, i, indexpos, indexlen, oflags, ncores; hostname = NULL; format = corefilename; name = malloc(MAXPATHLEN, M_TEMP, M_WAITOK | M_ZERO); indexlen = 0; indexpos = -1; ncores = num_cores; (void)sbuf_new(&sb, name, MAXPATHLEN, SBUF_FIXEDLEN); sx_slock(&corefilename_lock); for (i = 0; format[i] != '\0'; i++) { switch (format[i]) { case '%': /* Format character */ i++; switch (format[i]) { case '%': sbuf_putc(&sb, '%'); break; case 'H': /* hostname */ if (hostname == NULL) { hostname = malloc(MAXHOSTNAMELEN, M_TEMP, M_WAITOK); } getcredhostname(td->td_ucred, hostname, MAXHOSTNAMELEN); sbuf_printf(&sb, "%s", hostname); break; case 'I': /* autoincrementing index */ if (indexpos != -1) { sbuf_printf(&sb, "%%I"); break; } indexpos = sbuf_len(&sb); sbuf_printf(&sb, "%u", ncores - 1); indexlen = sbuf_len(&sb) - indexpos; break; case 'N': /* process name */ sbuf_printf(&sb, "%s", comm); break; case 'P': /* process id */ sbuf_printf(&sb, "%u", pid); break; case 'S': /* signal number */ sbuf_printf(&sb, "%i", signum); break; case 'U': /* user id */ sbuf_printf(&sb, "%u", uid); break; default: log(LOG_ERR, "Unknown format character %c in " "corename `%s'\n", format[i], format); break; } break; default: sbuf_putc(&sb, format[i]); break; } } sx_sunlock(&corefilename_lock); free(hostname, M_TEMP); if (compress == COMPRESS_GZIP) sbuf_printf(&sb, GZIP_SUFFIX); else if (compress == COMPRESS_ZSTD) sbuf_printf(&sb, ZSTD_SUFFIX); if (sbuf_error(&sb) != 0) { log(LOG_ERR, "pid %ld (%s), uid (%lu): corename is too " "long\n", (long)pid, comm, (u_long)uid); sbuf_delete(&sb); free(name, M_TEMP); return (ENOMEM); } sbuf_finish(&sb); sbuf_delete(&sb); if (indexpos != -1) { error = corefile_open_last(td, name, indexpos, indexlen, ncores, vpp); if (error != 0) { log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s' failed " "on initial open test, error = %d\n", pid, comm, uid, name, error); } } else { cmode = S_IRUSR | S_IWUSR; oflags = VN_OPEN_NOAUDIT | VN_OPEN_NAMECACHE | (capmode_coredump ? VN_OPEN_NOCAPCHECK : 0); flags = O_CREAT | FWRITE | O_NOFOLLOW; if ((td->td_proc->p_flag & P_SUGID) != 0) flags |= O_EXCL; NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name); error = vn_open_cred(&nd, &flags, cmode, oflags, td->td_ucred, NULL); if (error == 0) { *vpp = nd.ni_vp; NDFREE_PNBUF(&nd); } } if (error != 0) { #ifdef AUDIT audit_proc_coredump(td, name, error); #endif free(name, M_TEMP); return (error); } *namep = name; return (0); } /* * Dump a process' core. The main routine does some * policy checking, and creates the name of the coredump; * then it passes on a vnode and a size limit to the process-specific * coredump routine if there is one; if there _is not_ one, it returns * ENOSYS; otherwise it returns the error from the process-specific routine. */ static int coredump(struct thread *td) { struct proc *p = td->td_proc; struct ucred *cred = td->td_ucred; struct vnode *vp; struct flock lf; struct vattr vattr; size_t fullpathsize; int error, error1, locked; char *name; /* name of corefile */ void *rl_cookie; off_t limit; char *fullpath, *freepath = NULL; struct sbuf *sb; PROC_LOCK_ASSERT(p, MA_OWNED); MPASS((p->p_flag & P_HADTHREADS) == 0 || p->p_singlethread == td); if (!do_coredump || (!sugid_coredump && (p->p_flag & P_SUGID) != 0) || (p->p_flag2 & P2_NOTRACE) != 0) { PROC_UNLOCK(p); return (EFAULT); } /* * Note that the bulk of limit checking is done after * the corefile is created. The exception is if the limit * for corefiles is 0, in which case we don't bother * creating the corefile at all. This layout means that * a corefile is truncated instead of not being created, * if it is larger than the limit. */ limit = (off_t)lim_cur(td, RLIMIT_CORE); if (limit == 0 || racct_get_available(p, RACCT_CORE) == 0) { PROC_UNLOCK(p); return (EFBIG); } PROC_UNLOCK(p); error = corefile_open(p->p_comm, cred->cr_uid, p->p_pid, td, compress_user_cores, p->p_sig, &vp, &name); if (error != 0) return (error); /* * Don't dump to non-regular files or files with links. * Do not dump into system files. Effective user must own the corefile. */ if (vp->v_type != VREG || VOP_GETATTR(vp, &vattr, cred) != 0 || vattr.va_nlink != 1 || (vp->v_vflag & VV_SYSTEM) != 0 || vattr.va_uid != cred->cr_uid) { VOP_UNLOCK(vp); error = EFAULT; goto out; } VOP_UNLOCK(vp); /* Postpone other writers, including core dumps of other processes. */ rl_cookie = vn_rangelock_wlock(vp, 0, OFF_MAX); lf.l_whence = SEEK_SET; lf.l_start = 0; lf.l_len = 0; lf.l_type = F_WRLCK; locked = (VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, F_FLOCK) == 0); VATTR_NULL(&vattr); vattr.va_size = 0; if (set_core_nodump_flag) vattr.va_flags = UF_NODUMP; vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); VOP_SETATTR(vp, &vattr, cred); VOP_UNLOCK(vp); PROC_LOCK(p); p->p_acflag |= ACORE; PROC_UNLOCK(p); if (p->p_sysent->sv_coredump != NULL) { error = p->p_sysent->sv_coredump(td, vp, limit, 0); } else { error = ENOSYS; } if (locked) { lf.l_type = F_UNLCK; VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK); } vn_rangelock_unlock(vp, rl_cookie); /* * Notify the userland helper that a process triggered a core dump. * This allows the helper to run an automated debugging session. */ if (error != 0 || coredump_devctl == 0) goto out; sb = sbuf_new_auto(); if (vn_fullpath_global(p->p_textvp, &fullpath, &freepath) != 0) goto out2; sbuf_printf(sb, "comm=\""); devctl_safe_quote_sb(sb, fullpath); free(freepath, M_TEMP); sbuf_printf(sb, "\" core=\""); /* * We can't lookup core file vp directly. When we're replacing a core, and * other random times, we flush the name cache, so it will fail. Instead, * if the path of the core is relative, add the current dir in front if it. */ if (name[0] != '/') { fullpathsize = MAXPATHLEN; freepath = malloc(fullpathsize, M_TEMP, M_WAITOK); if (vn_getcwd(freepath, &fullpath, &fullpathsize) != 0) { free(freepath, M_TEMP); goto out2; } devctl_safe_quote_sb(sb, fullpath); free(freepath, M_TEMP); sbuf_putc(sb, '/'); } devctl_safe_quote_sb(sb, name); sbuf_printf(sb, "\""); if (sbuf_finish(sb) == 0) devctl_notify("kernel", "signal", "coredump", sbuf_data(sb)); out2: sbuf_delete(sb); out: error1 = vn_close(vp, FWRITE, cred, td); if (error == 0) error = error1; #ifdef AUDIT audit_proc_coredump(td, name, error); #endif free(name, M_TEMP); 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). */ #ifndef _SYS_SYSPROTO_H_ struct nosys_args { int dummy; }; #endif /* ARGSUSED */ int nosys(struct thread *td, struct nosys_args *args) { struct proc *p; p = td->td_proc; PROC_LOCK(p); tdsignal(td, SIGSYS); PROC_UNLOCK(p); if (kern_lognosys == 1 || kern_lognosys == 3) { uprintf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm, td->td_sa.code); } if (kern_lognosys == 2 || kern_lognosys == 3 || (p->p_pid == 1 && (kern_lognosys & 3) == 0)) { printf("pid %d comm %s: nosys %d\n", p->p_pid, p->p_comm, td->td_sa.code); } return (ENOSYS); } /* * Send a SIGIO or SIGURG signal to a process or process group using stored * credentials rather than those of the current process. */ void pgsigio(struct sigio **sigiop, int sig, int checkctty) { ksiginfo_t ksi; struct sigio *sigio; ksiginfo_init(&ksi); ksi.ksi_signo = sig; ksi.ksi_code = SI_KERNEL; SIGIO_LOCK(); sigio = *sigiop; if (sigio == NULL) { SIGIO_UNLOCK(); return; } if (sigio->sio_pgid > 0) { PROC_LOCK(sigio->sio_proc); if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc->p_ucred)) kern_psignal(sigio->sio_proc, sig); PROC_UNLOCK(sigio->sio_proc); } else if (sigio->sio_pgid < 0) { struct proc *p; PGRP_LOCK(sigio->sio_pgrp); LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) { PROC_LOCK(p); if (p->p_state == PRS_NORMAL && CANSIGIO(sigio->sio_ucred, p->p_ucred) && (checkctty == 0 || (p->p_flag & P_CONTROLT))) kern_psignal(p, sig); PROC_UNLOCK(p); } PGRP_UNLOCK(sigio->sio_pgrp); } SIGIO_UNLOCK(); } static int filt_sigattach(struct knote *kn) { struct proc *p = curproc; kn->kn_ptr.p_proc = p; kn->kn_flags |= EV_CLEAR; /* automatically set */ knlist_add(p->p_klist, kn, 0); return (0); } static void filt_sigdetach(struct knote *kn) { struct proc *p = kn->kn_ptr.p_proc; knlist_remove(p->p_klist, kn, 0); } /* * 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); } struct sigacts * sigacts_alloc(void) { struct sigacts *ps; ps = malloc(sizeof(struct sigacts), M_SUBPROC, M_WAITOK | M_ZERO); refcount_init(&ps->ps_refcnt, 1); mtx_init(&ps->ps_mtx, "sigacts", NULL, MTX_DEF); return (ps); } void sigacts_free(struct sigacts *ps) { if (refcount_release(&ps->ps_refcnt) == 0) return; mtx_destroy(&ps->ps_mtx); free(ps, M_SUBPROC); } struct sigacts * sigacts_hold(struct sigacts *ps) { refcount_acquire(&ps->ps_refcnt); return (ps); } void sigacts_copy(struct sigacts *dest, struct sigacts *src) { KASSERT(dest->ps_refcnt == 1, ("sigacts_copy to shared dest")); mtx_lock(&src->ps_mtx); bcopy(src, dest, offsetof(struct sigacts, ps_refcnt)); mtx_unlock(&src->ps_mtx); } int sigacts_shared(struct sigacts *ps) { return (ps->ps_refcnt > 1); } void sig_drop_caught(struct proc *p) { int sig; struct sigacts *ps; ps = p->p_sigacts; PROC_LOCK_ASSERT(p, MA_OWNED); mtx_assert(&ps->ps_mtx, MA_OWNED); SIG_FOREACH(sig, &ps->ps_sigcatch) { sigdflt(ps, sig); if ((sigprop(sig) & SIGPROP_IGNORE) != 0) sigqueue_delete_proc(p, sig); } } static void sigfastblock_failed(struct thread *td, bool sendsig, bool write) { ksiginfo_t ksi; /* * Prevent further fetches and SIGSEGVs, allowing thread to * issue syscalls despite corruption. */ sigfastblock_clear(td); if (!sendsig) return; ksiginfo_init_trap(&ksi); ksi.ksi_signo = SIGSEGV; ksi.ksi_code = write ? SEGV_ACCERR : SEGV_MAPERR; ksi.ksi_addr = td->td_sigblock_ptr; trapsignal(td, &ksi); } static bool sigfastblock_fetch_sig(struct thread *td, bool sendsig, uint32_t *valp) { uint32_t res; if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) return (true); if (fueword32((void *)td->td_sigblock_ptr, &res) == -1) { sigfastblock_failed(td, sendsig, false); return (false); } *valp = res; td->td_sigblock_val = res & ~SIGFASTBLOCK_FLAGS; return (true); } static void sigfastblock_resched(struct thread *td, bool resched) { struct proc *p; if (resched) { p = td->td_proc; PROC_LOCK(p); reschedule_signals(p, td->td_sigmask, 0); PROC_UNLOCK(p); } ast_sched(td, TDA_SIG); } int sys_sigfastblock(struct thread *td, struct sigfastblock_args *uap) { struct proc *p; int error, res; uint32_t oldval; error = 0; p = td->td_proc; switch (uap->cmd) { case SIGFASTBLOCK_SETPTR: if ((td->td_pflags & TDP_SIGFASTBLOCK) != 0) { error = EBUSY; break; } if (((uintptr_t)(uap->ptr) & (sizeof(uint32_t) - 1)) != 0) { error = EINVAL; break; } td->td_pflags |= TDP_SIGFASTBLOCK; td->td_sigblock_ptr = uap->ptr; break; case SIGFASTBLOCK_UNBLOCK: if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) { error = EINVAL; break; } for (;;) { res = casueword32(td->td_sigblock_ptr, SIGFASTBLOCK_PEND, &oldval, 0); if (res == -1) { error = EFAULT; sigfastblock_failed(td, false, true); break; } if (res == 0) break; MPASS(res == 1); if (oldval != SIGFASTBLOCK_PEND) { error = EBUSY; break; } error = thread_check_susp(td, false); if (error != 0) break; } if (error != 0) break; /* * td_sigblock_val is cleared there, but not on a * syscall exit. The end effect is that a single * interruptible sleep, while user sigblock word is * set, might return EINTR or ERESTART to usermode * without delivering signal. All further sleeps, * until userspace clears the word and does * sigfastblock(UNBLOCK), observe current word and no * longer get interrupted. It is slight * non-conformance, with alternative to have read the * sigblock word on each syscall entry. */ td->td_sigblock_val = 0; /* * Rely on normal ast mechanism to deliver pending * signals to current thread. But notify others about * fake unblock. */ sigfastblock_resched(td, error == 0 && p->p_numthreads != 1); break; case SIGFASTBLOCK_UNSETPTR: if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) { error = EINVAL; break; } if (!sigfastblock_fetch_sig(td, false, &oldval)) { error = EFAULT; break; } if (oldval != 0 && oldval != SIGFASTBLOCK_PEND) { error = EBUSY; break; } sigfastblock_clear(td); break; default: error = EINVAL; break; } return (error); } void sigfastblock_clear(struct thread *td) { bool resched; if ((td->td_pflags & TDP_SIGFASTBLOCK) == 0) return; td->td_sigblock_val = 0; resched = (td->td_pflags & TDP_SIGFASTPENDING) != 0 || SIGPENDING(td); td->td_pflags &= ~(TDP_SIGFASTBLOCK | TDP_SIGFASTPENDING); sigfastblock_resched(td, resched); } void sigfastblock_fetch(struct thread *td) { uint32_t val; (void)sigfastblock_fetch_sig(td, true, &val); } static void sigfastblock_setpend1(struct thread *td) { int res; uint32_t oldval; if ((td->td_pflags & TDP_SIGFASTPENDING) == 0) return; res = fueword32((void *)td->td_sigblock_ptr, &oldval); if (res == -1) { sigfastblock_failed(td, true, false); return; } for (;;) { res = casueword32(td->td_sigblock_ptr, oldval, &oldval, oldval | SIGFASTBLOCK_PEND); if (res == -1) { sigfastblock_failed(td, true, true); return; } if (res == 0) { td->td_sigblock_val = oldval & ~SIGFASTBLOCK_FLAGS; td->td_pflags &= ~TDP_SIGFASTPENDING; break; } MPASS(res == 1); if (thread_check_susp(td, false) != 0) break; } } static void sigfastblock_setpend(struct thread *td, bool resched) { struct proc *p; sigfastblock_setpend1(td); if (resched) { p = td->td_proc; PROC_LOCK(p); reschedule_signals(p, fastblock_mask, SIGPROCMASK_FASTBLK); PROC_UNLOCK(p); } }