/* * 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 * $FreeBSD: src/sys/kern/kern_sig.c,v 1.72.2.17 2003/05/16 16:34:34 obrien Exp $ */ #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 static int coredump(struct lwp *, int); static char *expand_name(const char *, uid_t, pid_t); static int dokillpg(int sig, int pgid, int all); static int sig_ffs(sigset_t *set); static int sigprop(int sig); static void lwp_signotify(struct lwp *lp); static void lwp_signotify_remote(void *arg); static int kern_sigtimedwait(sigset_t set, siginfo_t *info, struct timespec *timeout); static void proc_stopwait(struct proc *p); static int filt_sigattach(struct knote *kn); static void filt_sigdetach(struct knote *kn); static int filt_signal(struct knote *kn, long hint); struct filterops sig_filtops = { FILTEROP_MPSAFE, filt_sigattach, filt_sigdetach, 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)"); /* * Can process p send the signal sig to process q? Only processes within * the current reaper or children of the current reaper can be signaled. * Normally the reaper itself cannot be signalled, unless initok is set. */ #define CANSIGNAL(q, sig, initok) \ ((!p_trespass(curproc->p_ucred, (q)->p_ucred) && \ reaper_sigtest(curproc, p, initok)) || \ ((sig) == SIGCONT && (q)->p_session == curproc->p_session)) /* * Policy -- Can real uid ruid with ucred uc send a signal to process q? */ #define CANSIGIO(ruid, uc, q) \ ((uc)->cr_uid == 0 || \ (ruid) == (q)->p_ucred->cr_ruid || \ (uc)->cr_uid == (q)->p_ucred->cr_ruid || \ (ruid) == (q)->p_ucred->cr_uid || \ (uc)->cr_uid == (q)->p_ucred->cr_uid) int sugid_coredump; SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW, &sugid_coredump, 0, "Enable coredumping set user/group ID processes"); static int do_coredump = 1; SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, &do_coredump, 0, "Enable/Disable coredumps"); /* * Signal properties and actions. * The array below categorizes the signals and their default actions * according to the following properties: */ #define SA_KILL 0x01 /* terminates process by default */ #define SA_CORE 0x02 /* ditto and coredumps */ #define SA_STOP 0x04 /* suspend process */ #define SA_TTYSTOP 0x08 /* ditto, from tty */ #define SA_IGNORE 0x10 /* ignore by default */ #define SA_CONT 0x20 /* continue if suspended */ #define SA_CANTMASK 0x40 /* non-maskable, catchable */ #define SA_CKPT 0x80 /* checkpoint process */ static int sigproptbl[NSIG] = { SA_KILL, /* SIGHUP */ SA_KILL, /* SIGINT */ SA_KILL|SA_CORE, /* SIGQUIT */ SA_KILL|SA_CORE, /* SIGILL */ SA_KILL|SA_CORE, /* SIGTRAP */ SA_KILL|SA_CORE, /* SIGABRT */ SA_KILL|SA_CORE, /* SIGEMT */ SA_KILL|SA_CORE, /* SIGFPE */ SA_KILL, /* SIGKILL */ SA_KILL|SA_CORE, /* SIGBUS */ SA_KILL|SA_CORE, /* SIGSEGV */ SA_KILL|SA_CORE, /* SIGSYS */ SA_KILL, /* SIGPIPE */ SA_KILL, /* SIGALRM */ SA_KILL, /* SIGTERM */ SA_IGNORE, /* SIGURG */ SA_STOP, /* SIGSTOP */ SA_STOP|SA_TTYSTOP, /* SIGTSTP */ SA_IGNORE|SA_CONT, /* SIGCONT */ SA_IGNORE, /* SIGCHLD */ SA_STOP|SA_TTYSTOP, /* SIGTTIN */ SA_STOP|SA_TTYSTOP, /* SIGTTOU */ SA_IGNORE, /* SIGIO */ SA_KILL, /* SIGXCPU */ SA_KILL, /* SIGXFSZ */ SA_KILL, /* SIGVTALRM */ SA_KILL, /* SIGPROF */ SA_IGNORE, /* SIGWINCH */ SA_IGNORE, /* SIGINFO */ SA_KILL, /* SIGUSR1 */ SA_KILL, /* SIGUSR2 */ SA_IGNORE, /* SIGTHR */ SA_CKPT, /* SIGCKPT */ SA_KILL|SA_CKPT, /* SIGCKPTEXIT */ SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, SA_IGNORE, }; __read_mostly sigset_t sigcantmask_mask; static __inline int sigprop(int sig) { if (sig > 0 && sig < NSIG) return (sigproptbl[_SIG_IDX(sig)]); return (0); } static __inline int sig_ffs(sigset_t *set) { int i; for (i = 0; i < _SIG_WORDS; i++) if (set->__bits[i]) return (ffs(set->__bits[i]) + (i * 32)); return (0); } /* * Allows us to populate siginfo->si_pid and si_uid in the target process * (p) from the originating thread (td). This function must work properly * even if a kernel thread is sending the signal. * * NOTE: Signals are not queued, so if multiple signals are received the * signal handler will only see the most recent pid and uid for any * given signal number. */ static __inline void sigsetfrompid(thread_t td, struct proc *p, int sig) { struct sigacts *sap; if ((sap = p->p_sigacts) == NULL) return; if (td->td_proc) { sap->ps_frominfo[sig].pid = td->td_proc->p_pid; sap->ps_frominfo[sig].uid = td->td_ucred->cr_uid; } else { sap->ps_frominfo[sig].pid = 0; sap->ps_frominfo[sig].uid = 0; } } /* * No requirements. */ int kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact) { struct thread *td = curthread; struct proc *p = td->td_proc; struct lwp *lp; struct sigacts *ps = p->p_sigacts; if (sig <= 0 || sig >= _SIG_MAXSIG) return (EINVAL); lwkt_gettoken(&p->p_token); if (oact) { oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; oact->sa_flags = 0; 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; if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDSTOP) oact->sa_flags |= SA_NOCLDSTOP; if (sig == SIGCHLD && p->p_sigacts->ps_flag & PS_NOCLDWAIT) oact->sa_flags |= SA_NOCLDWAIT; } if (act) { /* * Check for invalid requests. KILL and STOP cannot be * caught. */ if (sig == SIGKILL || sig == SIGSTOP) { if (act->sa_handler != SIG_DFL) { lwkt_reltoken(&p->p_token); return (EINVAL); } } /* * Change setting atomically. */ ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); if (act->sa_flags & 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 (!(act->sa_flags & SA_RESTART)) SIGADDSET(ps->ps_sigintr, sig); else SIGDELSET(ps->ps_sigintr, sig); if (act->sa_flags & SA_ONSTACK) SIGADDSET(ps->ps_sigonstack, sig); else SIGDELSET(ps->ps_sigonstack, sig); if (act->sa_flags & SA_RESETHAND) SIGADDSET(ps->ps_sigreset, sig); else SIGDELSET(ps->ps_sigreset, sig); if (act->sa_flags & SA_NODEFER) SIGADDSET(ps->ps_signodefer, sig); else SIGDELSET(ps->ps_signodefer, sig); if (sig == SIGCHLD) { if (act->sa_flags & SA_NOCLDSTOP) p->p_sigacts->ps_flag |= PS_NOCLDSTOP; else p->p_sigacts->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) p->p_sigacts->ps_flag &= ~PS_NOCLDWAIT; else p->p_sigacts->ps_flag |= PS_NOCLDWAIT; } else { p->p_sigacts->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 p_sigignore for signals that are set to SIG_IGN, * and for signals set to SIG_DFL where the default is to * ignore. However, don't put SIGCONT in p_sigignore, as we * have to restart the process. * * Also remove the signal from the process and lwp signal * list. */ if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || (sigprop(sig) & SA_IGNORE && ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { SIGDELSET_ATOMIC(p->p_siglist, sig); FOREACH_LWP_IN_PROC(lp, p) { spin_lock(&lp->lwp_spin); SIGDELSET(lp->lwp_siglist, sig); spin_unlock(&lp->lwp_spin); } if (sig != SIGCONT) { /* easier in ksignal */ SIGADDSET(p->p_sigignore, sig); } SIGDELSET(p->p_sigcatch, sig); } else { SIGDELSET(p->p_sigignore, sig); if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) SIGDELSET(p->p_sigcatch, sig); else SIGADDSET(p->p_sigcatch, sig); } } lwkt_reltoken(&p->p_token); return (0); } int sys_sigaction(struct sysmsg *sysmsg, const 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(uap->sig, actp, oactp); if (oactp && !error) { error = copyout(oactp, uap->oact, sizeof(oact)); } return (error); } /* * Initialize signal state for process 0; * set to ignore signals that are ignored by default. */ void siginit(struct proc *p) { int i; for (i = 1; i <= NSIG; i++) { if (sigprop(i) & SA_IGNORE && i != SIGCONT) SIGADDSET(p->p_sigignore, i); } /* * Also initialize signal-related global state. */ SIGSETOR_CANTMASK(sigcantmask_mask); } /* * Reset signals for an exec of the specified process. */ void execsigs(struct proc *p) { struct sigacts *ps = p->p_sigacts; struct lwp *lp; int sig; lp = ONLY_LWP_IN_PROC(p); /* * Reset caught signals. Held signals remain held * through p_sigmask (unless they were caught, * and are now ignored by default). */ while (SIGNOTEMPTY(p->p_sigcatch)) { sig = sig_ffs(&p->p_sigcatch); SIGDELSET(p->p_sigcatch, sig); if (sigprop(sig) & SA_IGNORE) { if (sig != SIGCONT) SIGADDSET(p->p_sigignore, sig); SIGDELSET_ATOMIC(p->p_siglist, sig); /* don't need spinlock */ SIGDELSET(lp->lwp_siglist, sig); } ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; } /* * Reset stack state to the user stack. * Clear set of signals caught on the signal stack. */ lp->lwp_sigstk.ss_flags = SS_DISABLE; lp->lwp_sigstk.ss_size = 0; lp->lwp_sigstk.ss_sp = NULL; lp->lwp_flags &= ~LWP_ALTSTACK; /* * Reset no zombies if child dies flag as Solaris does. */ p->p_sigacts->ps_flag &= ~(PS_NOCLDWAIT | PS_CLDSIGIGN); if (ps->ps_sigact[_SIG_IDX(SIGCHLD)] == SIG_IGN) ps->ps_sigact[_SIG_IDX(SIGCHLD)] = SIG_DFL; } /* * kern_sigprocmask() - MP SAFE ONLY IF p == curproc * * Manipulate signal mask. This routine is MP SAFE *ONLY* if * p == curproc. */ int kern_sigprocmask(int how, sigset_t *set, sigset_t *oset) { struct thread *td = curthread; struct lwp *lp = td->td_lwp; struct proc *p = td->td_proc; int error; lwkt_gettoken(&p->p_token); if (oset != NULL) *oset = lp->lwp_sigmask; error = 0; if (set != NULL) { switch (how) { case SIG_BLOCK: SIG_CANTMASK(*set); SIGSETOR(lp->lwp_sigmask, *set); break; case SIG_UNBLOCK: SIGSETNAND(lp->lwp_sigmask, *set); break; case SIG_SETMASK: SIG_CANTMASK(*set); lp->lwp_sigmask = *set; sigirefs_wait(p); break; default: error = EINVAL; break; } } lwkt_reltoken(&p->p_token); return (error); } /* * sigprocmask() * * MPSAFE */ int sys_sigprocmask(struct sysmsg *sysmsg, const 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(uap->how, setp, osetp); if (osetp && !error) { error = copyout(osetp, uap->oset, sizeof(oset)); } return (error); } /* * MPSAFE */ int kern_sigpending(sigset_t *set) { struct lwp *lp = curthread->td_lwp; *set = lwp_sigpend(lp); return (0); } /* * MPSAFE */ int sys_sigpending(struct sysmsg *sysmsg, const struct sigpending_args *uap) { sigset_t set; int error; error = kern_sigpending(&set); if (error == 0) error = copyout(&set, uap->set, sizeof(set)); return (error); } /* * Suspend process until signal, providing mask to be set * in the meantime. * * MPSAFE */ int kern_sigsuspend(sigset_t *set) { struct thread *td = curthread; struct lwp *lp = td->td_lwp; struct proc *p = td->td_proc; struct sigacts *ps = p->p_sigacts; /* * 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. * * To interlock signal deliveries which may race this function, we * must hold the LWP token, otherwise the signal may be made pending * to the process rather than the lwp during execution of the tsleep() * (which does not hold the process token to interlock that) and be * missed by the tsleep(). */ lwkt_gettoken(&lp->lwp_token); lp->lwp_oldsigmask = lp->lwp_sigmask; lp->lwp_flags |= LWP_OLDMASK; SIG_CANTMASK(*set); lp->lwp_sigmask = *set; lwkt_reltoken(&lp->lwp_token); sigirefs_wait(p); while (tsleep(ps, PCATCH, "pause", 0) == 0) /* void */; /* always return EINTR rather than ERESTART... */ return (EINTR); } /* * Note nonstandard calling convention: libc stub passes mask, not * pointer, to save a copyin. * * MPSAFE */ int sys_sigsuspend(struct sysmsg *sysmsg, const struct sigsuspend_args *uap) { sigset_t mask; int error; error = copyin(uap->sigmask, &mask, sizeof(mask)); if (error) return (error); error = kern_sigsuspend(&mask); return (error); } /* * MPSAFE */ int kern_sigaltstack(stack_t *ss, stack_t *oss) { struct thread *td = curthread; struct lwp *lp = td->td_lwp; struct proc *p = td->td_proc; if ((lp->lwp_flags & LWP_ALTSTACK) == 0) lp->lwp_sigstk.ss_flags |= SS_DISABLE; if (oss) *oss = lp->lwp_sigstk; if (ss) { if (ss->ss_flags & ~SS_DISABLE) return (EINVAL); if (ss->ss_flags & SS_DISABLE) { if (lp->lwp_sigstk.ss_flags & SS_ONSTACK) return (EPERM); lp->lwp_flags &= ~LWP_ALTSTACK; lp->lwp_sigstk.ss_flags = ss->ss_flags; } else { if (ss->ss_size < p->p_sysent->sv_minsigstksz) return (ENOMEM); lp->lwp_flags |= LWP_ALTSTACK; lp->lwp_sigstk = *ss; } } return (0); } /* * MPSAFE */ int sys_sigaltstack(struct sysmsg *sysmsg, const struct sigaltstack_args *uap) { stack_t ss, oss; int error; if (uap->ss) { error = copyin(uap->ss, &ss, sizeof(ss)); if (error) return (error); } error = kern_sigaltstack(uap->ss ? &ss : NULL, uap->oss ? &oss : NULL); if (error == 0 && uap->oss) error = copyout(&oss, uap->oss, sizeof(*uap->oss)); return (error); } /* * Common code for kill process group/broadcast kill. * cp is calling process. */ struct killpg_info { int nfound; int sig; }; static int killpg_all_callback(struct proc *p, void *data); static int dokillpg(int sig, int pgid, int all) { struct killpg_info info; struct proc *cp = curproc; struct proc *p; struct pgrp *pgrp; info.nfound = 0; info.sig = sig; if (all) { /* * broadcast */ allproc_scan(killpg_all_callback, &info, 0); } else { if (pgid == 0) { /* * zero pgid means send to my process group. */ pgrp = cp->p_pgrp; pgref(pgrp); } else { pgrp = pgfind(pgid); if (pgrp == NULL) return (ESRCH); } /* * Must interlock all signals against fork */ lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { if (p->p_pid <= 1 || p->p_stat == SZOMB || (p->p_flags & P_SYSTEM) || !CANSIGNAL(p, sig, 0)) { continue; } ++info.nfound; if (sig) ksignal(p, sig); } lockmgr(&pgrp->pg_lock, LK_RELEASE); pgrel(pgrp); } return (info.nfound ? 0 : ESRCH); } static int killpg_all_callback(struct proc *p, void *data) { struct killpg_info *info = data; if (p->p_pid <= 1 || (p->p_flags & P_SYSTEM) || p == curproc || !CANSIGNAL(p, info->sig, 0)) { return (0); } ++info->nfound; if (info->sig) ksignal(p, info->sig); return(0); } /* * Send a general signal to a process or LWPs within that process. * * Note that new signals cannot be sent if a process is exiting or already * a zombie, but we return success anyway as userland is likely to not handle * the race properly. * * No requirements. */ int kern_kill(int sig, pid_t pid, lwpid_t tid) { int t; if ((u_int)sig >= _SIG_MAXSIG) return (EINVAL); if (pid > 0) { struct proc *p; struct lwp *lp = NULL; /* * Sending a signal to pid 1 as root requires that we * are not reboot-restricted. */ if (pid == 1 && caps_priv_check_self(SYSCAP_NOREBOOT)) return EPERM; /* * Send a signal to a single process. If the kill() is * racing an exiting process which has not yet been reaped * act as though the signal was delivered successfully but * don't actually try to deliver the signal. */ if ((p = pfind(pid)) == NULL) { if ((p = zpfind(pid)) == NULL) return (ESRCH); PRELE(p); return (0); } if (p != curproc) { lwkt_gettoken_shared(&p->p_token); if (!CANSIGNAL(p, sig, 1)) { lwkt_reltoken(&p->p_token); PRELE(p); return (EPERM); } lwkt_reltoken(&p->p_token); } /* * NOP if the process is exiting. Note that lwpsignal() is * called directly with P_WEXIT set to kill individual LWPs * during exit, which is allowed. */ if (p->p_flags & P_WEXIT) { PRELE(p); return (0); } if (tid != -1) { lwkt_gettoken_shared(&p->p_token); lp = lwp_rb_tree_RB_LOOKUP(&p->p_lwp_tree, tid); if (lp == NULL) { lwkt_reltoken(&p->p_token); PRELE(p); return (ESRCH); } LWPHOLD(lp); lwkt_reltoken(&p->p_token); } if (sig) lwpsignal(p, lp, sig); if (lp) LWPRELE(lp); PRELE(p); return (0); } /* * If we come here, pid is a special broadcast pid. * This doesn't mix with a tid. */ if (tid != -1) return (EINVAL); switch (pid) { case -1: /* broadcast signal */ t = (dokillpg(sig, 0, 1)); break; case 0: /* signal own process group */ t = (dokillpg(sig, 0, 0)); break; default: /* negative explicit process group */ t = (dokillpg(sig, -pid, 0)); break; } return t; } int sys_kill(struct sysmsg *sysmsg, const struct kill_args *uap) { int error; error = kern_kill(uap->signum, uap->pid, -1); return (error); } int sys_lwp_kill(struct sysmsg *sysmsg, const struct lwp_kill_args *uap) { int error; pid_t pid = uap->pid; /* * A tid is mandatory for lwp_kill(), otherwise * you could simply use kill(). */ if (uap->tid == -1) return (EINVAL); /* * To save on a getpid() function call for intra-process * signals, pid == -1 means current process. */ if (pid == -1) pid = curproc->p_pid; error = kern_kill(uap->signum, pid, uap->tid); return (error); } /* * Send a signal to a process group. */ void gsignal(int pgid, int sig) { struct pgrp *pgrp; if (pgid && (pgrp = pgfind(pgid))) pgsignal(pgrp, sig, 0); } /* * Send a signal to a process group. If checktty is 1, * limit to members which have a controlling terminal. * * pg_lock interlocks against a fork that might be in progress, to * ensure that the new child process picks up the signal. */ void pgsignal(struct pgrp *pgrp, int sig, int checkctty) { struct proc *p; /* * Must interlock all signals against fork */ if (pgrp) { pgref(pgrp); lockmgr(&pgrp->pg_lock, LK_EXCLUSIVE); LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { if (checkctty == 0 || p->p_flags & P_CONTROLT) ksignal(p, sig); } lockmgr(&pgrp->pg_lock, LK_RELEASE); pgrel(pgrp); } } /* * Send a signal caused by a trap to the current lwp. If it will be caught * immediately, deliver it with correct code. Otherwise, post it normally. * * These signals may ONLY be delivered to the specified lwp and may never * be delivered to the process generically. * * lpmap->blockallsigs is ignored. */ void trapsignal(struct lwp *lp, int sig, u_long code) { struct proc *p = lp->lwp_proc; struct sigacts *ps = p->p_sigacts; /* * If we are a virtual kernel running an emulated user process * context, switch back to the virtual kernel context before * trying to post the signal. */ if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { struct trapframe *tf = lp->lwp_md.md_regs; tf->tf_trapno = 0; vkernel_trap(lp, tf); } if ((p->p_flags & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && !SIGISMEMBER(lp->lwp_sigmask, sig)) { lp->lwp_ru.ru_nsignals++; #ifdef KTRACE if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) ktrpsig(lp, sig, ps->ps_sigact[_SIG_IDX(sig)], &lp->lwp_sigmask, code); #endif (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, &lp->lwp_sigmask, code); SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); if (!SIGISMEMBER(ps->ps_signodefer, sig)) SIGADDSET(lp->lwp_sigmask, sig); if (SIGISMEMBER(ps->ps_sigreset, sig)) { /* * See kern_sigaction() for origin of this code. */ SIGDELSET(p->p_sigcatch, sig); if (sig != SIGCONT && sigprop(sig) & SA_IGNORE) SIGADDSET(p->p_sigignore, sig); ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; } } else { lp->lwp_code = code; /* XXX for core dump/debugger */ lp->lwp_sig = sig; /* XXX to verify code */ lwpsignal(p, lp, sig); } } /* * Find a suitable lwp to deliver the signal to. Returns NULL if all * lwps hold the signal blocked. * * Caller must hold p->p_token. * * Returns a lp or NULL. If non-NULL the lp is held and its token is * acquired. */ static struct lwp * find_lwp_for_signal(struct proc *p, int sig) { struct lwp *lp; struct lwp *run, *sleep, *stop; /* * If the running/preempted thread belongs to the proc to which * the signal is being delivered and this thread does not block * the signal, then we can avoid a context switch by delivering * the signal to this thread, because it will return to userland * soon anyways. */ lp = lwkt_preempted_proc(); if (lp != NULL && lp->lwp_proc == p) { LWPHOLD(lp); lwkt_gettoken(&lp->lwp_token); if (!SIGISMEMBER(lp->lwp_sigmask, sig)) { /* return w/ token held */ return (lp); } lwkt_reltoken(&lp->lwp_token); LWPRELE(lp); } run = sleep = stop = NULL; FOREACH_LWP_IN_PROC(lp, p) { /* * If the signal is being blocked by the lwp, then this * lwp is not eligible for receiving the signal. */ LWPHOLD(lp); lwkt_gettoken(&lp->lwp_token); if (SIGISMEMBER(lp->lwp_sigmask, sig)) { lwkt_reltoken(&lp->lwp_token); LWPRELE(lp); continue; } switch (lp->lwp_stat) { case LSRUN: if (sleep) { lwkt_token_swap(); lwkt_reltoken(&sleep->lwp_token); LWPRELE(sleep); sleep = NULL; run = lp; } else if (stop) { lwkt_token_swap(); lwkt_reltoken(&stop->lwp_token); LWPRELE(stop); stop = NULL; run = lp; } else { run = lp; } break; case LSSLEEP: if (lp->lwp_flags & LWP_SINTR) { if (sleep) { lwkt_reltoken(&lp->lwp_token); LWPRELE(lp); } else if (stop) { lwkt_token_swap(); lwkt_reltoken(&stop->lwp_token); LWPRELE(stop); stop = NULL; sleep = lp; } else { sleep = lp; } } else { lwkt_reltoken(&lp->lwp_token); LWPRELE(lp); } break; case LSSTOP: if (sleep) { lwkt_reltoken(&lp->lwp_token); LWPRELE(lp); } else if (stop) { lwkt_reltoken(&lp->lwp_token); LWPRELE(lp); } else { stop = lp; } break; } if (run) break; } if (run != NULL) return (run); else if (sleep != NULL) return (sleep); else return (stop); } /* * 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. * * If the caller wishes to call this function from a hard code section the * caller must already hold p->p_token (see kern_clock.c). * * No requirements. */ void ksignal(struct proc *p, int sig) { lwpsignal(p, NULL, sig); } /* * The core for ksignal. lp may be NULL, then a suitable thread * will be chosen. If not, lp MUST be a member of p. * * If the caller wishes to call this function from a hard code section the * caller must already hold p->p_token. * * No requirements. */ void lwpsignal(struct proc *p, struct lwp *lp, int sig) { struct proc *q; sig_t action; int prop; if (sig >= _SIG_MAXSIG || sig <= 0) { kprintf("lwpsignal: signal %d\n", sig); panic("lwpsignal signal number"); } KKASSERT(lp == NULL || lp->lwp_proc == p); /* * We don't want to race... well, all sorts of things. Get appropriate * tokens. * * Don't try to deliver a generic signal to an exiting process, * the signal structures could be in flux. We check the LWP later * on. */ PHOLD(p); if (lp) { LWPHOLD(lp); lwkt_gettoken(&lp->lwp_token); } else { lwkt_gettoken(&p->p_token); if (p->p_flags & P_WEXIT) goto out; } prop = sigprop(sig); /* * If proc is traced, always give parent a chance; * if signal event is tracked by procfs, give *that* * a chance, as well. */ if ((p->p_flags & P_TRACED) || (p->p_stops & S_SIG)) { action = SIG_DFL; } else { /* * Do not try to deliver signals to an exiting lwp other * than SIGKILL. Note that we must still deliver the signal * if P_WEXIT is set in the process flags. */ if (lp && (lp->lwp_mpflags & LWP_MP_WEXIT) && sig != SIGKILL) { lwkt_reltoken(&lp->lwp_token); LWPRELE(lp); PRELE(p); return; } /* * If the signal is being ignored, then we forget about * it immediately. NOTE: We don't set SIGCONT in p_sigignore, * and if it is set to SIG_IGN, action will be SIG_DFL here. */ if (SIGISMEMBER(p->p_sigignore, sig)) { /* * Even if a signal is set SIG_IGN, it may still be * lurking in a kqueue. */ KNOTE(&p->p_klist, NOTE_SIGNAL | sig); if (lp) { lwkt_reltoken(&lp->lwp_token); LWPRELE(lp); } else { lwkt_reltoken(&p->p_token); } PRELE(p); return; } if (SIGISMEMBER(p->p_sigcatch, sig)) action = SIG_CATCH; else action = SIG_DFL; } /* * If continuing, clear any pending STOP signals for the whole * process. */ if (prop & SA_CONT) { lwkt_gettoken(&p->p_token); SIG_STOPSIGMASK_ATOMIC(p->p_siglist); lwkt_reltoken(&p->p_token); } if (prop & SA_STOP) { /* * If sending a tty stop signal to a member of an orphaned * process group, discard the signal here if the action * is default; don't stop the process below if sleeping, * and don't clear any pending SIGCONT. */ if ((prop & SA_TTYSTOP) && p->p_pgrp->pg_jobc == 0 && action == SIG_DFL) { if (lp) { lwkt_reltoken(&lp->lwp_token); LWPRELE(lp); } else { lwkt_reltoken(&p->p_token); } PRELE(p); return; } lwkt_gettoken(&p->p_token); SIG_CONTSIGMASK_ATOMIC(p->p_siglist); p->p_flags &= ~P_CONTINUED; lwkt_reltoken(&p->p_token); } if (p->p_stat == SSTOP) { /* * Nobody can handle this signal, add it to the lwp or * process pending list */ lwkt_gettoken(&p->p_token); if (p->p_stat != SSTOP) { lwkt_reltoken(&p->p_token); goto not_stopped; } sigsetfrompid(curthread, p, sig); if (lp) { spin_lock(&lp->lwp_spin); SIGADDSET(lp->lwp_siglist, sig); spin_unlock(&lp->lwp_spin); } else { SIGADDSET_ATOMIC(p->p_siglist, sig); } /* * If the process is stopped and is being traced, then no * further action is necessary. */ if (p->p_flags & P_TRACED) { lwkt_reltoken(&p->p_token); goto out; } /* * If the process is stopped and receives a KILL signal, * make the process runnable. */ if (sig == SIGKILL) { proc_unstop(p, SSTOP); lwkt_reltoken(&p->p_token); goto active_process; } /* * If the process is stopped and receives a CONT signal, * then try to make the process runnable again. */ if (prop & SA_CONT) { /* * If SIGCONT is default (or ignored), we continue the * process but don't leave the signal in p_siglist, as * it has no further action. If SIGCONT is held, we * continue the process and leave the signal in * p_siglist. If the process catches SIGCONT, let it * handle the signal itself. * * XXX what if the signal is being held blocked? * * Token required to interlock kern_wait(). * Reparenting can also cause a race so we have to * hold (q). */ q = p->p_pptr; PHOLD(q); lwkt_gettoken(&q->p_token); p->p_flags |= P_CONTINUED; wakeup(q); if (action == SIG_DFL) SIGDELSET_ATOMIC(p->p_siglist, sig); proc_unstop(p, SSTOP); lwkt_reltoken(&q->p_token); PRELE(q); lwkt_reltoken(&p->p_token); if (action == SIG_CATCH) goto active_process; goto out; } /* * If the process is stopped and receives another STOP * signal, we do not need to stop it again. If we did * the shell could get confused. * * However, if the current/preempted lwp is part of the * process receiving the signal, we need to keep it, * so that this lwp can stop in issignal() later, as * we don't want to wait until it reaches userret! */ if (prop & SA_STOP) { if (lwkt_preempted_proc() == NULL || lwkt_preempted_proc()->lwp_proc != p) { SIGDELSET_ATOMIC(p->p_siglist, sig); } } /* * Otherwise the process is stopped and it received some * signal, which does not change its stopped state. When * the process is continued a wakeup(p) will be issued which * will wakeup any threads sleeping in tstop(). */ lwkt_reltoken(&p->p_token); goto out; /* NOTREACHED */ } not_stopped: ; /* else not stopped */ active_process: /* * Never deliver a lwp-specific signal to a random lwp. * * When delivering an untargetted signal, use p_sigirefs to * inform lwps of potential collisions. */ if (lp == NULL) { /* NOTE: returns lp w/ token held */ sigirefs_hold(p); lp = find_lwp_for_signal(p, sig); if (lp) { if (SIGISMEMBER(lp->lwp_sigmask, sig)) { lwkt_reltoken(&lp->lwp_token); LWPRELE(lp); lp = NULL; /* maintain proc token */ /* maintain sigirefs */ } else { lwkt_token_swap(); lwkt_reltoken(&p->p_token); /* maintain lp token */ sigirefs_drop(p); } } } /* * Deliver to the process generically if (1) the signal is being * sent to any thread or (2) we could not find a thread to deliver * it to. * * Drop p_sigirefs after the signal has been resolved to interlock * against sigsuspend/ppoll/pselect. */ if (lp == NULL) { sigsetfrompid(curthread, p, sig); KNOTE(&p->p_klist, NOTE_SIGNAL | sig); SIGADDSET_ATOMIC(p->p_siglist, sig); sigirefs_drop(p); goto out; } /* * Deliver to a specific LWP whether it masks it or not. It will * not be dispatched if masked but we must still deliver it. */ if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && (p->p_flags & P_TRACED) == 0) { lwkt_gettoken(&p->p_token); p->p_nice = NZERO; lwkt_reltoken(&p->p_token); } /* * If the process receives a STOP signal which indeed needs to * stop the process, do so. If the process chose to catch the * signal, it will be treated like any other signal. */ if ((prop & SA_STOP) && action == SIG_DFL) { /* * If a child holding parent blocked, stopping * could cause deadlock. Take no action at this * time. */ lwkt_gettoken(&p->p_token); if (p->p_flags & P_PPWAIT) { sigsetfrompid(curthread, p, sig); SIGADDSET_ATOMIC(p->p_siglist, sig); lwkt_reltoken(&p->p_token); goto out; } /* * Do not actually try to manipulate the process, but simply * stop it. Lwps will stop as soon as they safely can. * * Ignore stop if the process is exiting. */ if ((p->p_flags & P_WEXIT) == 0) { p->p_xstat = sig; proc_stop(p, SSTOP); } lwkt_reltoken(&p->p_token); goto out; } /* * If it is a CONT signal with default action, just ignore it. */ if ((prop & SA_CONT) && action == SIG_DFL) goto out; /* * Mark signal pending at this specific thread. */ sigsetfrompid(curthread, p, sig); spin_lock(&lp->lwp_spin); SIGADDSET(lp->lwp_siglist, sig); spin_unlock(&lp->lwp_spin); lwp_signotify(lp); out: if (lp) { lwkt_reltoken(&lp->lwp_token); LWPRELE(lp); } else { lwkt_reltoken(&p->p_token); } PRELE(p); } /* * Notify the LWP that a signal has arrived. The LWP does not have to be * sleeping on the current cpu. * * p->p_token and lp->lwp_token must be held on call. * * We can only safely schedule the thread on its current cpu and only if * one of the SINTR flags is set. If an SINTR flag is set AND we are on * the correct cpu we are properly interlocked, otherwise we could be * racing other thread transition states (or the lwp is on the user scheduler * runq but not scheduled) and must not do anything. * * Since we hold the lwp token we know the lwp cannot be ripped out from * under us so we can safely hold it to prevent it from being ripped out * from under us if we are forced to IPI another cpu to make the local * checks there. * * Adjustment of lp->lwp_stat can only occur when we hold the lwp_token, * which we won't in an IPI so any fixups have to be done here, effectively * replicating part of what setrunnable() does. */ static void lwp_signotify(struct lwp *lp) { thread_t dtd; ASSERT_LWKT_TOKEN_HELD(&lp->lwp_token); dtd = lp->lwp_thread; crit_enter(); if (lp == lwkt_preempted_proc()) { /* * lwp is on the current cpu AND it is currently running * (we preempted it). */ signotify(); } else if (lp->lwp_flags & LWP_SINTR) { /* * lwp is sitting in tsleep() with PCATCH set */ if (dtd->td_gd == mycpu) { setrunnable(lp); } else { /* * We can only adjust lwp_stat while we hold the * lwp_token, and we won't in the IPI function. */ LWPHOLD(lp); if (lp->lwp_stat == LSSTOP) lp->lwp_stat = LSSLEEP; lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp); } } else if (dtd->td_flags & TDF_SINTR) { /* * lwp is sitting in lwkt_sleep() with PCATCH set. */ if (dtd->td_gd == mycpu) { setrunnable(lp); } else { /* * We can only adjust lwp_stat while we hold the * lwp_token, and we won't in the IPI function. */ LWPHOLD(lp); if (lp->lwp_stat == LSSTOP) lp->lwp_stat = LSSLEEP; lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp); } } else { /* * Otherwise the lwp is either in some uninterruptible state * or it is on the userland scheduler's runqueue waiting to * be scheduled to a cpu, or it is running in userland. We * generally want to send an IPI so a running target gets the * signal ASAP, otherwise a scheduler-tick worth of latency * will occur. * * Issue an IPI to the remote cpu to knock it into the kernel, * remote cpu will issue the cpu-local signotify() if the IPI * preempts the desired thread. */ if (dtd->td_gd != mycpu) { LWPHOLD(lp); lwkt_send_ipiq(dtd->td_gd, lwp_signotify_remote, lp); } } crit_exit(); } /* * This function is called via an IPI so we cannot call setrunnable() here * (because while we hold the lp we don't own its token, and can't get it * from an IPI). * * We are interlocked by virtue of being on the same cpu as the target. If * we still are and LWP_SINTR or TDF_SINTR is set we can safely schedule * the target thread. */ static void lwp_signotify_remote(void *arg) { struct lwp *lp = arg; thread_t td = lp->lwp_thread; if (lp == lwkt_preempted_proc()) { signotify(); LWPRELE(lp); } else if (td->td_gd == mycpu) { if ((lp->lwp_flags & LWP_SINTR) || (td->td_flags & TDF_SINTR)) { lwkt_schedule(td); } LWPRELE(lp); } else { lwkt_send_ipiq(td->td_gd, lwp_signotify_remote, lp); /* LWPHOLD() is forwarded to the target cpu */ } } /* * Caller must hold p->p_token */ void proc_stop(struct proc *p, int stat) { struct proc *q; struct lwp *lp; ASSERT_LWKT_TOKEN_HELD(&p->p_token); /* * If somebody raced us, be happy with it. SCORE overrides SSTOP. */ if (stat == SCORE) { if (p->p_stat == SCORE || p->p_stat == SZOMB) return; } else { if (p->p_stat == SSTOP || p->p_stat == SCORE || p->p_stat == SZOMB) { return; } } p->p_stat = stat; FOREACH_LWP_IN_PROC(lp, p) { LWPHOLD(lp); lwkt_gettoken(&lp->lwp_token); switch (lp->lwp_stat) { case LSSTOP: /* * Do nothing, we are already counted in * p_nstopped. */ break; case LSSLEEP: /* * We're sleeping, but we will stop before * returning to userspace, so count us * as stopped as well. We set LWP_MP_WSTOP * to signal the lwp that it should not * increase p_nstopped when reaching tstop(). * * LWP_MP_WSTOP is protected by lp->lwp_token. */ if ((lp->lwp_mpflags & LWP_MP_WSTOP) == 0) { atomic_set_int(&lp->lwp_mpflags, LWP_MP_WSTOP); ++p->p_nstopped; } break; case LSRUN: /* * We might notify ourself, but that's not * a problem. */ lwp_signotify(lp); break; } lwkt_reltoken(&lp->lwp_token); LWPRELE(lp); } if (p->p_nstopped == p->p_nthreads) { /* * Token required to interlock kern_wait(). Reparenting can * also cause a race so we have to hold (q). */ q = p->p_pptr; PHOLD(q); lwkt_gettoken(&q->p_token); p->p_flags &= ~P_WAITED; wakeup(q); if ((q->p_sigacts->ps_flag & PS_NOCLDSTOP) == 0) ksignal(p->p_pptr, SIGCHLD); lwkt_reltoken(&q->p_token); PRELE(q); } } /* * Caller must hold p_token */ void proc_unstop(struct proc *p, int stat) { struct lwp *lp; ASSERT_LWKT_TOKEN_HELD(&p->p_token); if (p->p_stat != stat) return; p->p_stat = SACTIVE; FOREACH_LWP_IN_PROC(lp, p) { LWPHOLD(lp); lwkt_gettoken(&lp->lwp_token); switch (lp->lwp_stat) { case LSRUN: /* * Uh? Not stopped? Well, I guess that's okay. */ if (bootverbose) kprintf("proc_unstop: lwp %d/%d not sleeping\n", p->p_pid, lp->lwp_tid); break; case LSSLEEP: /* * Still sleeping. Don't bother waking it up. * However, if this thread was counted as * stopped, undo this. * * Nevertheless we call setrunnable() so that it * will wake up in case a signal or timeout arrived * in the meantime. * * LWP_MP_WSTOP is protected by lp->lwp_token. */ if (lp->lwp_mpflags & LWP_MP_WSTOP) { atomic_clear_int(&lp->lwp_mpflags, LWP_MP_WSTOP); --p->p_nstopped; } else { if (bootverbose) kprintf("proc_unstop: lwp %d/%d sleeping, not stopped\n", p->p_pid, lp->lwp_tid); } /* FALLTHROUGH */ case LSSTOP: /* * This handles any lwp's waiting in a tsleep with * SIGCATCH. */ lwp_signotify(lp); break; } lwkt_reltoken(&lp->lwp_token); LWPRELE(lp); } /* * This handles any lwp's waiting in tstop(). We have interlocked * the setting of p_stat by acquiring and releasing each lpw's * token. */ wakeup(p); } /* * Wait for all threads except the current thread to stop. */ static void proc_stopwait(struct proc *p) { while ((p->p_stat == SSTOP || p->p_stat == SCORE) && p->p_nstopped < p->p_nthreads - 1) { tsleep_interlock(&p->p_nstopped, 0); if (p->p_nstopped < p->p_nthreads - 1) { tsleep(&p->p_nstopped, PINTERLOCKED, "stopwt", hz); } } } /* * No requirements. */ static int kern_sigtimedwait(sigset_t waitset, siginfo_t *info, struct timespec *timeout) { sigset_t savedmask, set; struct proc *p = curproc; struct lwp *lp = curthread->td_lwp; int error, sig, hz, timevalid = 0; struct timespec rts, ets, ts; struct timeval tv; error = 0; sig = 0; ets.tv_sec = 0; /* silence compiler warning */ ets.tv_nsec = 0; /* silence compiler warning */ SIG_CANTMASK(waitset); savedmask = lp->lwp_sigmask; if (timeout) { if (timeout->tv_sec >= 0 && timeout->tv_nsec >= 0 && timeout->tv_nsec < 1000000000) { timevalid = 1; getnanouptime(&rts); timespecadd(&rts, timeout, &ets); } } for (;;) { set = lwp_sigpend(lp); SIGSETAND(set, waitset); if ((sig = sig_ffs(&set)) != 0) { SIGFILLSET(lp->lwp_sigmask); SIGDELSET(lp->lwp_sigmask, sig); SIG_CANTMASK(lp->lwp_sigmask); sig = issignal(lp, 1, 0); /* * It may be a STOP signal, in the case, issignal * returns 0, because we may stop there, and new * signal can come in, we should restart if we got * nothing. */ if (sig == 0) continue; else break; } /* * Previous checking got nothing, and we retried but still * got nothing, we should return the error status. */ if (error) break; /* * POSIX says this must be checked after looking for pending * signals. */ if (timeout) { if (timevalid == 0) { error = EINVAL; break; } getnanouptime(&rts); if (timespeccmp(&rts, &ets, >=)) { error = EAGAIN; break; } timespecsub(&ets, &rts, &ts); TIMESPEC_TO_TIMEVAL(&tv, &ts); hz = tvtohz_high(&tv); } else { hz = 0; } lp->lwp_sigmask = savedmask; SIGSETNAND(lp->lwp_sigmask, waitset); sigirefs_wait(p); /* * We won't ever be woken up. Instead, our sleep will * be broken in lwpsignal(). */ error = tsleep(&p->p_sigacts, PCATCH, "sigwt", hz); if (timeout) { if (error == ERESTART) { /* can not restart a timeout wait. */ error = EINTR; } else if (error == EAGAIN) { /* will calculate timeout by ourself. */ error = 0; } } /* Retry ... */ } lp->lwp_sigmask = savedmask; sigirefs_wait(p); if (sig) { error = 0; bzero(info, sizeof(*info)); info->si_signo = sig; spin_lock(&lp->lwp_spin); lwp_delsig(lp, sig, 1); /* take the signal! */ spin_unlock(&lp->lwp_spin); if (sig == SIGKILL) { sigexit(lp, sig); /* NOT REACHED */ } } return (error); } /* * MPALMOSTSAFE */ int sys_sigtimedwait(struct sysmsg *sysmsg, const struct sigtimedwait_args *uap) { struct timespec ts; struct timespec *timeout; sigset_t set; siginfo_t info; 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(set, &info, timeout); if (error) return (error); if (uap->info) error = copyout(&info, uap->info, sizeof(info)); /* Repost if we got an error. */ /* * XXX lwp * * This could transform a thread-specific signal to another * thread / process pending signal. */ if (error) { ksignal(curproc, info.si_signo); } else { sysmsg->sysmsg_result = info.si_signo; } return (error); } /* * MPALMOSTSAFE */ int sys_sigwaitinfo(struct sysmsg *sysmsg, const struct sigwaitinfo_args *uap) { siginfo_t info; sigset_t set; int error; error = copyin(uap->set, &set, sizeof(set)); if (error) return (error); error = kern_sigtimedwait(set, &info, NULL); if (error) return (error); if (uap->info) error = copyout(&info, uap->info, sizeof(info)); /* Repost if we got an error. */ /* * XXX lwp * * This could transform a thread-specific signal to another * thread / process pending signal. */ if (error) { ksignal(curproc, info.si_signo); } else { sysmsg->sysmsg_result = info.si_signo; } return (error); } /* * If the current process has received a signal that would interrupt a * system call, return EINTR or ERESTART as appropriate. */ int iscaught(struct lwp *lp) { struct proc *p = lp->lwp_proc; int sig; if (p) { if ((sig = CURSIG(lp)) != 0) { if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) return (EINTR); return (ERESTART); } } return(EWOULDBLOCK); } /* * If the current lwp/proc has received a signal (should be caught or cause * termination, should interrupt current syscall), return the signal number. * Stop signals with default action are processed immediately, then cleared; * they aren't returned. This is checked after each entry to the system for * a syscall or trap (though this can usually be done without calling issignal * by checking the pending signal masks in the CURSIG macro). * * This routine is called via CURSIG/__cursig. We will acquire and release * p->p_token but if the caller needs to interlock the test the caller must * also hold p->p_token. * * while (sig = CURSIG(curproc)) * postsig(sig); */ int issignal(struct lwp *lp, int maytrace, int *ptokp) { struct proc *p = lp->lwp_proc; sigset_t mask; int sig, prop; int haveptok; for (;;) { int traced = (p->p_flags & P_TRACED) || (p->p_stops & S_SIG); haveptok = 0; /* * NOTE: Do not tstop here. Issue the proc_stop() * so other parties see that we know we need * to stop, but don't block here. Locks might * be held. * * XXX If this process is supposed to stop, stop this thread. * removed. */ #if 0 if (STOPLWP(p, lp)) { lwkt_gettoken(&p->p_token); tstop(); lwkt_reltoken(&p->p_token); } #endif /* * Quick check without token */ mask = lwp_sigpend(lp); SIGSETNAND(mask, lp->lwp_sigmask); if (p->p_flags & P_PPWAIT) SIG_STOPSIGMASK(mask); SIG_CONDBLOCKALLSIGS(mask, lp); if (SIGISEMPTY(mask)) /* no signal to send */ return (0); /* * If the signal is a member of the process signal set * we need p_token (even if it is also a member of the * lwp signal set). */ sig = sig_ffs(&mask); if (SIGISMEMBER(p->p_siglist, sig)) { /* * Recheck with token */ haveptok = 1; lwkt_gettoken(&p->p_token); mask = lwp_sigpend(lp); SIGSETNAND(mask, lp->lwp_sigmask); if (p->p_flags & P_PPWAIT) SIG_STOPSIGMASK(mask); if (SIGISEMPTY(mask)) { /* no signal to send */ /* haveptok is TRUE */ lwkt_reltoken(&p->p_token); return (0); } sig = sig_ffs(&mask); } STOPEVENT(p, S_SIG, sig); /* * We should see pending but ignored signals * only if P_TRACED was on when they were posted. */ if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { spin_lock(&lp->lwp_spin); lwp_delsig(lp, sig, haveptok); spin_unlock(&lp->lwp_spin); if (haveptok) lwkt_reltoken(&p->p_token); continue; } if (maytrace && (p->p_flags & P_TRACED) && (p->p_flags & P_PPWAIT) == 0) { /* * If traced, always stop, and stay stopped until * released by the parent. * * NOTE: SSTOP may get cleared during the loop, but * we do not re-notify the parent if we have * to loop several times waiting for the parent * to let us continue. XXX not sure if this is * still true * * NOTE: Do not tstop here. Issue the proc_stop() * so other parties see that we know we need * to stop, but don't block here. Locks might * be held. */ if (haveptok == 0) { lwkt_gettoken(&p->p_token); haveptok = 1; } p->p_xstat = sig; proc_stop(p, SSTOP); /* * Normally we don't stop until we return to userland, but * make an exception when tracing and 'maytrace' is asserted. */ if (p->p_flags & P_TRACED) tstop(); /* * If parent wants us to take the signal, * then it will leave it in p->p_xstat; * otherwise we just look for signals again. */ spin_lock(&lp->lwp_spin); lwp_delsig(lp, sig, 1); /* clear old signal */ spin_unlock(&lp->lwp_spin); sig = p->p_xstat; if (sig == 0) { /* haveptok is TRUE */ lwkt_reltoken(&p->p_token); continue; } /* * Put the new signal into p_siglist. If the * signal is being masked, look for other signals. * * XXX lwp might need a call to ksignal() */ SIGADDSET_ATOMIC(p->p_siglist, sig); if (SIGISMEMBER(lp->lwp_sigmask, sig)) { /* haveptok is TRUE */ lwkt_reltoken(&p->p_token); continue; } /* * If the traced bit got turned off, go back up * to the top to rescan signals. This ensures * that p_sig* and ps_sigact are consistent. */ if ((p->p_flags & P_TRACED) == 0) { /* haveptok is TRUE */ lwkt_reltoken(&p->p_token); continue; } } /* * p_token may be held here */ prop = sigprop(sig); /* * 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 */ kprintf("Process (pid %lu) got signal %d\n", (u_long)p->p_pid, sig); #endif break; /* == ignore */ } /* * Handle the in-kernel checkpoint action */ if (prop & SA_CKPT) { if (haveptok == 0) { lwkt_gettoken(&p->p_token); haveptok = 1; } checkpoint_signal_handler(lp); break; } /* * If there is a pending stop signal to process * with default action, stop here, * then clear the signal. However, * if process is member of an orphaned * process group, ignore tty stop signals. */ if (prop & SA_STOP) { if (haveptok == 0) { lwkt_gettoken(&p->p_token); haveptok = 1; } if (p->p_flags & P_TRACED || (p->p_pgrp->pg_jobc == 0 && prop & SA_TTYSTOP)) break; /* == ignore */ if ((p->p_flags & P_WEXIT) == 0) { /* * NOTE: We do not block here. Issue * stopthe stop so other parties * see that we know we need to * stop. Locks might be held. */ p->p_xstat = sig; proc_stop(p, SSTOP); #if 0 tstop(); #endif } break; } else if (prop & SA_IGNORE) { /* * Except for SIGCONT, shouldn't get here. * Default action is to ignore; drop it. */ break; /* == ignore */ } else { if (ptokp) *ptokp = haveptok; else if (haveptok) lwkt_reltoken(&p->p_token); return (sig); } /*NOTREACHED*/ case (intptr_t)SIG_IGN: /* * Masking above should prevent us ever trying * to take action on an ignored signal other * than SIGCONT, unless process is traced. */ if ((prop & SA_CONT) == 0 && (p->p_flags & P_TRACED) == 0) kprintf("issignal\n"); break; /* == ignore */ default: /* * This signal has an action, let * postsig() process it. */ if (ptokp) *ptokp = haveptok; else if (haveptok) lwkt_reltoken(&p->p_token); return (sig); } spin_lock(&lp->lwp_spin); lwp_delsig(lp, sig, haveptok); /* take the signal! */ spin_unlock(&lp->lwp_spin); if (haveptok) lwkt_reltoken(&p->p_token); } /* NOTREACHED */ } /* * Take the action for the specified signal from the current set of * pending signals. * * haveptok indicates whether the caller is holding p->p_token. If the * caller is, we are responsible for releasing it. * * This routine can only be called from the top-level trap from usermode. * It is expecting to be able to modify the top-level stack frame. */ void postsig(int sig, int haveptok) { struct lwp *lp = curthread->td_lwp; struct proc *p = lp->lwp_proc; struct sigacts *ps = p->p_sigacts; sig_t action; sigset_t returnmask; int code; KASSERT(sig != 0, ("postsig")); /* * If we are a virtual kernel running an emulated user process * context, switch back to the virtual kernel context before * trying to post the signal. */ if (lp->lwp_vkernel && lp->lwp_vkernel->ve) { struct trapframe *tf = lp->lwp_md.md_regs; tf->tf_trapno = 0; vkernel_trap(lp, tf); } KNOTE(&p->p_klist, NOTE_SIGNAL | sig); spin_lock(&lp->lwp_spin); lwp_delsig(lp, sig, haveptok); spin_unlock(&lp->lwp_spin); action = ps->ps_sigact[_SIG_IDX(sig)]; #ifdef KTRACE if (KTRPOINT(lp->lwp_thread, KTR_PSIG)) ktrpsig(lp, sig, action, lp->lwp_flags & LWP_OLDMASK ? &lp->lwp_oldsigmask : &lp->lwp_sigmask, 0); #endif /* * We don't need p_token after this point. */ if (haveptok) lwkt_reltoken(&p->p_token); STOPEVENT(p, S_SIG, sig); if (action == SIG_DFL) { /* * Default action, where the default is to kill * the process. (Other cases were ignored above.) */ sigexit(lp, sig); /* NOTREACHED */ } else { /* * If we get here, the signal must be caught. */ KASSERT(action != SIG_IGN && !SIGISMEMBER(lp->lwp_sigmask, sig), ("postsig action")); /* * Reset the signal handler if asked to */ if (SIGISMEMBER(ps->ps_sigreset, sig)) { /* * See kern_sigaction() for origin of this code. */ SIGDELSET(p->p_sigcatch, sig); if (sig != SIGCONT && sigprop(sig) & SA_IGNORE) SIGADDSET(p->p_sigignore, sig); ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; } /* * Set the signal mask and calculate the mask to restore * when the signal function returns. * * 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 (lp->lwp_flags & LWP_OLDMASK) { returnmask = lp->lwp_oldsigmask; lp->lwp_flags &= ~LWP_OLDMASK; } else { returnmask = lp->lwp_sigmask; } SIGSETOR(lp->lwp_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); if (!SIGISMEMBER(ps->ps_signodefer, sig)) SIGADDSET(lp->lwp_sigmask, sig); lp->lwp_ru.ru_nsignals++; if (lp->lwp_sig != sig) { code = 0; } else { code = lp->lwp_code; lp->lwp_code = 0; lp->lwp_sig = 0; } (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); } } /* * Kill the current process for stated reason. */ void killproc(struct proc *p, char *why) { log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", p->p_pid, p->p_comm, p->p_ucred ? p->p_ucred->cr_uid : -1, why); ksignal(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. * * This routine does not return. */ void sigexit(struct lwp *lp, int sig) { struct proc *p = lp->lwp_proc; lwkt_gettoken(&p->p_token); p->p_acflag |= AXSIG; if (sigprop(sig) & SA_CORE) { lp->lwp_sig = sig; /* * All threads must be stopped before we can safely coredump. * Stop threads using SCORE, which cannot be overridden. */ if (p->p_stat != SCORE) { proc_stop(p, SCORE); proc_stopwait(p); if (coredump(lp, sig) == 0) sig |= WCOREFLAG; p->p_stat = SSTOP; } /* * 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 */ if (kern_logsigexit) { log(LOG_INFO, "pid %d (%s), uid %d: exited on signal %d%s\n", p->p_pid, p->p_comm, p->p_ucred ? p->p_ucred->cr_uid : -1, sig &~ WCOREFLAG, sig & WCOREFLAG ? " (core dumped)" : ""); if (kern_logsigexit > 1) kprintf("DEBUG - waiting on kern.logsigexit\n"); while (kern_logsigexit > 1) { tsleep(&kern_logsigexit, 0, "DEBUG", hz); } } } lwkt_reltoken(&p->p_token); exit1(W_EXITCODE(0, sig)); /* NOTREACHED */ } static char corefilename[MAXPATHLEN+1] = {"%N.core"}; SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, sizeof(corefilename), "process corefile name format string"); /* * expand_name(name, uid, pid) * Expand the name described in corefilename, using name, uid, and pid. * corefilename is a kprintf-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 char * expand_name(const char *name, uid_t uid, pid_t pid) { char *temp; char buf[11]; /* Buffer for pid/uid -- max 4B */ int i, n; char *format = corefilename; size_t namelen; temp = kmalloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); if (temp == NULL) return NULL; namelen = strlen(name); for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { int l; switch (format[i]) { case '%': /* Format character */ i++; switch (format[i]) { case '%': temp[n++] = '%'; break; case 'N': /* process name */ if ((n + namelen) > MAXPATHLEN) { log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", pid, name, uid, temp, name); kfree(temp, M_TEMP); return NULL; } memcpy(temp+n, name, namelen); n += namelen; break; case 'P': /* process id */ l = ksprintf(buf, "%u", pid); if ((n + l) > MAXPATHLEN) { log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", pid, name, uid, temp, name); kfree(temp, M_TEMP); return NULL; } memcpy(temp+n, buf, l); n += l; break; case 'U': /* user id */ l = ksprintf(buf, "%u", uid); if ((n + l) > MAXPATHLEN) { log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", pid, name, uid, temp, name); kfree(temp, M_TEMP); return NULL; } memcpy(temp+n, buf, l); n += l; break; default: log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); } break; default: temp[n++] = format[i]; } } temp[n] = '\0'; return temp; } /* * 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. * * The parameter `lp' is the lwp which triggered the coredump. */ static int coredump(struct lwp *lp, int sig) { struct proc *p = lp->lwp_proc; struct vnode *vp; struct ucred *cred = p->p_ucred; struct flock lf; struct nlookupdata nd; struct vattr vattr; int error, error1; char *name; /* name of corefile */ off_t limit; STOPEVENT(p, S_CORE, 0); if (((sugid_coredump == 0) && (p->p_flags & P_SUGID)) || do_coredump == 0) { 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 = p->p_rlimit[RLIMIT_CORE].rlim_cur; if (limit == 0) return EFBIG; name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); if (name == NULL) return (EINVAL); error = nlookup_init(&nd, name, UIO_SYSSPACE, NLC_LOCKVP); if (error == 0) error = vn_open(&nd, NULL, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); kfree(name, M_TEMP); if (error) { nlookup_done(&nd); return (error); } vp = nd.nl_open_vp; nd.nl_open_vp = NULL; nlookup_done(&nd); vn_unlock(vp); lf.l_whence = SEEK_SET; lf.l_start = 0; lf.l_len = 0; lf.l_type = F_WRLCK; error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, 0); if (error) goto out2; /* Don't dump to non-regular files or files with links. */ if (vp->v_type != VREG || VOP_GETATTR(vp, &vattr) || vattr.va_nlink != 1) { error = EFAULT; goto out1; } /* Don't dump to files current user does not own */ if (vattr.va_uid != p->p_ucred->cr_uid) { error = EFAULT; goto out1; } VATTR_NULL(&vattr); vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); vattr.va_size = 0; VOP_SETATTR(vp, &vattr, cred); p->p_acflag |= ACORE; vn_unlock(vp); error = p->p_sysent->sv_coredump ? p->p_sysent->sv_coredump(lp, sig, vp, limit) : ENOSYS; out1: lf.l_type = F_UNLCK; VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, 0); out2: error1 = vn_close(vp, FWRITE, NULL); if (error == 0) error = error1; 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). * * MPALMOSTSAFE */ /* ARGSUSED */ int sys_nosys(struct sysmsg *sysmsg, const struct nosys_args *args) { lwpsignal(curproc, curthread->td_lwp, SIGSYS); return (EINVAL); } /* * 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 *sigio, int sig, int checkctty) { if (sigio == NULL) return; if (sigio->sio_pgid > 0) { if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, sigio->sio_proc)) ksignal(sigio->sio_proc, sig); } else if (sigio->sio_pgid < 0) { struct proc *p; struct pgrp *pg = sigio->sio_pgrp; /* * Must interlock all signals against fork */ pgref(pg); lockmgr(&pg->pg_lock, LK_EXCLUSIVE); LIST_FOREACH(p, &pg->pg_members, p_pglist) { if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && (checkctty == 0 || (p->p_flags & P_CONTROLT))) ksignal(p, sig); } lockmgr(&pg->pg_lock, LK_RELEASE); pgrel(pg); } } static int filt_sigattach(struct knote *kn) { struct proc *p = curproc; kn->kn_ptr.p_proc = p; kn->kn_flags |= EV_CLEAR; /* automatically set */ /* XXX lock the proc here while adding to the list? */ knote_insert(&p->p_klist, kn); return (0); } static void filt_sigdetach(struct knote *kn) { struct proc *p = kn->kn_ptr.p_proc; knote_remove(&p->p_klist, kn); } /* * 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); }