/* $OpenBSD: kern_sig.c,v 1.320 2023/10/06 08:58:13 claudio Exp $ */ /* $NetBSD: kern_sig.c,v 1.54 1996/04/22 01:38:32 christos Exp $ */ /* * Copyright (c) 1997 Theo de Raadt. All rights reserved. * Copyright (c) 1982, 1986, 1989, 1991, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. 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 #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 int nosuidcoredump = 1; int filt_sigattach(struct knote *kn); void filt_sigdetach(struct knote *kn); int filt_signal(struct knote *kn, long hint); const struct filterops sig_filtops = { .f_flags = 0, .f_attach = filt_sigattach, .f_detach = filt_sigdetach, .f_event = filt_signal, }; /* * The array below categorizes the signals and their default actions. */ const int sigprop[NSIG] = { 0, /* unused */ 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 */ }; #define CONTSIGMASK (sigmask(SIGCONT)) #define STOPSIGMASK (sigmask(SIGSTOP) | sigmask(SIGTSTP) | \ sigmask(SIGTTIN) | sigmask(SIGTTOU)) void setsigvec(struct proc *, int, struct sigaction *); void proc_stop(struct proc *p, int); void proc_stop_sweep(void *); void *proc_stop_si; void setsigctx(struct proc *, int, struct sigctx *); void postsig_done(struct proc *, int, sigset_t, int); void postsig(struct proc *, int, struct sigctx *); int cansignal(struct proc *, struct process *, int); struct pool sigacts_pool; /* memory pool for sigacts structures */ void sigio_del(struct sigiolst *); void sigio_unlink(struct sigio_ref *, struct sigiolst *); struct mutex sigio_lock = MUTEX_INITIALIZER(IPL_HIGH); /* * Can thread p, send the signal signum to process qr? */ int cansignal(struct proc *p, struct process *qr, int signum) { struct process *pr = p->p_p; struct ucred *uc = p->p_ucred; struct ucred *quc = qr->ps_ucred; if (uc->cr_uid == 0) return (1); /* root can always signal */ if (pr == qr) return (1); /* process can always signal itself */ /* optimization: if the same creds then the tests below will pass */ if (uc == quc) return (1); if (signum == SIGCONT && qr->ps_session == pr->ps_session) return (1); /* SIGCONT in session */ /* * Using kill(), only certain signals can be sent to setugid * child processes */ if (qr->ps_flags & PS_SUGID) { switch (signum) { case 0: case SIGKILL: case SIGINT: case SIGTERM: case SIGALRM: case SIGSTOP: case SIGTTIN: case SIGTTOU: case SIGTSTP: case SIGHUP: case SIGUSR1: case SIGUSR2: if (uc->cr_ruid == quc->cr_ruid || uc->cr_uid == quc->cr_ruid) return (1); } return (0); } if (uc->cr_ruid == quc->cr_ruid || uc->cr_ruid == quc->cr_svuid || uc->cr_uid == quc->cr_ruid || uc->cr_uid == quc->cr_svuid) return (1); return (0); } /* * Initialize signal-related data structures. */ void signal_init(void) { proc_stop_si = softintr_establish(IPL_SOFTCLOCK, proc_stop_sweep, NULL); if (proc_stop_si == NULL) panic("signal_init failed to register softintr"); pool_init(&sigacts_pool, sizeof(struct sigacts), 0, IPL_NONE, PR_WAITOK, "sigapl", NULL); } /* * Initialize a new sigaltstack structure. */ void sigstkinit(struct sigaltstack *ss) { ss->ss_flags = SS_DISABLE; ss->ss_size = 0; ss->ss_sp = NULL; } /* * Create an initial sigacts structure, using the same signal state * as pr. */ struct sigacts * sigactsinit(struct process *pr) { struct sigacts *ps; ps = pool_get(&sigacts_pool, PR_WAITOK); memcpy(ps, pr->ps_sigacts, sizeof(struct sigacts)); return (ps); } /* * Release a sigacts structure. */ void sigactsfree(struct sigacts *ps) { pool_put(&sigacts_pool, ps); } int sys_sigaction(struct proc *p, void *v, register_t *retval) { struct sys_sigaction_args /* { syscallarg(int) signum; syscallarg(const struct sigaction *) nsa; syscallarg(struct sigaction *) osa; } */ *uap = v; struct sigaction vec; #ifdef KTRACE struct sigaction ovec; #endif struct sigaction *sa; const struct sigaction *nsa; struct sigaction *osa; struct sigacts *ps = p->p_p->ps_sigacts; int signum; int bit, error; signum = SCARG(uap, signum); nsa = SCARG(uap, nsa); osa = SCARG(uap, osa); if (signum <= 0 || signum >= NSIG || (nsa && (signum == SIGKILL || signum == SIGSTOP))) return (EINVAL); sa = &vec; if (osa) { mtx_enter(&p->p_p->ps_mtx); sa->sa_handler = ps->ps_sigact[signum]; sa->sa_mask = ps->ps_catchmask[signum]; bit = sigmask(signum); sa->sa_flags = 0; if ((ps->ps_sigonstack & bit) != 0) sa->sa_flags |= SA_ONSTACK; if ((ps->ps_sigintr & bit) == 0) sa->sa_flags |= SA_RESTART; if ((ps->ps_sigreset & bit) != 0) sa->sa_flags |= SA_RESETHAND; if ((ps->ps_siginfo & bit) != 0) sa->sa_flags |= SA_SIGINFO; if (signum == SIGCHLD) { if ((ps->ps_sigflags & SAS_NOCLDSTOP) != 0) sa->sa_flags |= SA_NOCLDSTOP; if ((ps->ps_sigflags & SAS_NOCLDWAIT) != 0) sa->sa_flags |= SA_NOCLDWAIT; } mtx_leave(&p->p_p->ps_mtx); if ((sa->sa_mask & bit) == 0) sa->sa_flags |= SA_NODEFER; sa->sa_mask &= ~bit; error = copyout(sa, osa, sizeof (vec)); if (error) return (error); #ifdef KTRACE if (KTRPOINT(p, KTR_STRUCT)) ovec = vec; #endif } if (nsa) { error = copyin(nsa, sa, sizeof (vec)); if (error) return (error); #ifdef KTRACE if (KTRPOINT(p, KTR_STRUCT)) ktrsigaction(p, sa); #endif setsigvec(p, signum, sa); } #ifdef KTRACE if (osa && KTRPOINT(p, KTR_STRUCT)) ktrsigaction(p, &ovec); #endif return (0); } void setsigvec(struct proc *p, int signum, struct sigaction *sa) { struct sigacts *ps = p->p_p->ps_sigacts; int bit; bit = sigmask(signum); mtx_enter(&p->p_p->ps_mtx); ps->ps_sigact[signum] = sa->sa_handler; if ((sa->sa_flags & SA_NODEFER) == 0) sa->sa_mask |= sigmask(signum); ps->ps_catchmask[signum] = sa->sa_mask &~ sigcantmask; if (signum == SIGCHLD) { if (sa->sa_flags & SA_NOCLDSTOP) atomic_setbits_int(&ps->ps_sigflags, SAS_NOCLDSTOP); else atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDSTOP); /* * If the SA_NOCLDWAIT flag is set or the handler * is SIG_IGN we reparent the dying child to PID 1 * (init) which will reap the zombie. Because we use * init to do our dirty work we never set SAS_NOCLDWAIT * for PID 1. * XXX exit1 rework means this is unnecessary? */ if (initprocess->ps_sigacts != ps && ((sa->sa_flags & SA_NOCLDWAIT) || sa->sa_handler == SIG_IGN)) atomic_setbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); else atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); } if ((sa->sa_flags & SA_RESETHAND) != 0) ps->ps_sigreset |= bit; else ps->ps_sigreset &= ~bit; if ((sa->sa_flags & SA_SIGINFO) != 0) ps->ps_siginfo |= bit; else ps->ps_siginfo &= ~bit; if ((sa->sa_flags & SA_RESTART) == 0) ps->ps_sigintr |= bit; else ps->ps_sigintr &= ~bit; if ((sa->sa_flags & SA_ONSTACK) != 0) ps->ps_sigonstack |= bit; else ps->ps_sigonstack &= ~bit; /* * 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 (sa->sa_handler == SIG_IGN || (sigprop[signum] & SA_IGNORE && sa->sa_handler == SIG_DFL)) { atomic_clearbits_int(&p->p_siglist, bit); atomic_clearbits_int(&p->p_p->ps_siglist, bit); if (signum != SIGCONT) ps->ps_sigignore |= bit; /* easier in psignal */ ps->ps_sigcatch &= ~bit; } else { ps->ps_sigignore &= ~bit; if (sa->sa_handler == SIG_DFL) ps->ps_sigcatch &= ~bit; else ps->ps_sigcatch |= bit; } mtx_leave(&p->p_p->ps_mtx); } /* * Initialize signal state for process 0; * set to ignore signals that are ignored by default. */ void siginit(struct sigacts *ps) { int i; for (i = 0; i < NSIG; i++) if (sigprop[i] & SA_IGNORE && i != SIGCONT) ps->ps_sigignore |= sigmask(i); ps->ps_sigflags = SAS_NOCLDWAIT | SAS_NOCLDSTOP; } /* * Reset signals for an exec by the specified thread. */ void execsigs(struct proc *p) { struct sigacts *ps; int nc, mask; ps = p->p_p->ps_sigacts; mtx_enter(&p->p_p->ps_mtx); /* * Reset caught signals. Held signals remain held * through p_sigmask (unless they were caught, * and are now ignored by default). */ while (ps->ps_sigcatch) { nc = ffs((long)ps->ps_sigcatch); mask = sigmask(nc); ps->ps_sigcatch &= ~mask; if (sigprop[nc] & SA_IGNORE) { if (nc != SIGCONT) ps->ps_sigignore |= mask; atomic_clearbits_int(&p->p_siglist, mask); atomic_clearbits_int(&p->p_p->ps_siglist, mask); } ps->ps_sigact[nc] = SIG_DFL; } /* * Reset stack state to the user stack. * Clear set of signals caught on the signal stack. */ sigstkinit(&p->p_sigstk); atomic_clearbits_int(&ps->ps_sigflags, SAS_NOCLDWAIT); if (ps->ps_sigact[SIGCHLD] == SIG_IGN) ps->ps_sigact[SIGCHLD] = SIG_DFL; mtx_leave(&p->p_p->ps_mtx); } /* * Manipulate signal mask. * Note that we receive new mask, not pointer, * and return old mask as return value; * the library stub does the rest. */ int sys_sigprocmask(struct proc *p, void *v, register_t *retval) { struct sys_sigprocmask_args /* { syscallarg(int) how; syscallarg(sigset_t) mask; } */ *uap = v; int error = 0; sigset_t mask; KASSERT(p == curproc); *retval = p->p_sigmask; mask = SCARG(uap, mask) &~ sigcantmask; switch (SCARG(uap, how)) { case SIG_BLOCK: atomic_setbits_int(&p->p_sigmask, mask); break; case SIG_UNBLOCK: atomic_clearbits_int(&p->p_sigmask, mask); break; case SIG_SETMASK: p->p_sigmask = mask; break; default: error = EINVAL; break; } return (error); } int sys_sigpending(struct proc *p, void *v, register_t *retval) { *retval = p->p_siglist | p->p_p->ps_siglist; return (0); } /* * Temporarily replace calling proc's signal mask for the duration of a * system call. Original signal mask will be restored by userret(). */ void dosigsuspend(struct proc *p, sigset_t newmask) { KASSERT(p == curproc); p->p_oldmask = p->p_sigmask; atomic_setbits_int(&p->p_flag, P_SIGSUSPEND); p->p_sigmask = newmask; } /* * Suspend thread until signal, providing mask to be set * in the meantime. Note nonstandard calling convention: * libc stub passes mask, not pointer, to save a copyin. */ int sys_sigsuspend(struct proc *p, void *v, register_t *retval) { struct sys_sigsuspend_args /* { syscallarg(int) mask; } */ *uap = v; dosigsuspend(p, SCARG(uap, mask) &~ sigcantmask); while (tsleep_nsec(&nowake, PPAUSE|PCATCH, "sigsusp", INFSLP) == 0) continue; /* always return EINTR rather than ERESTART... */ return (EINTR); } int sigonstack(size_t stack) { const struct sigaltstack *ss = &curproc->p_sigstk; return (ss->ss_flags & SS_DISABLE ? 0 : (stack - (size_t)ss->ss_sp < ss->ss_size)); } int sys_sigaltstack(struct proc *p, void *v, register_t *retval) { struct sys_sigaltstack_args /* { syscallarg(const struct sigaltstack *) nss; syscallarg(struct sigaltstack *) oss; } */ *uap = v; struct sigaltstack ss; const struct sigaltstack *nss; struct sigaltstack *oss; int onstack = sigonstack(PROC_STACK(p)); int error; nss = SCARG(uap, nss); oss = SCARG(uap, oss); if (oss != NULL) { ss = p->p_sigstk; if (onstack) ss.ss_flags |= SS_ONSTACK; if ((error = copyout(&ss, oss, sizeof(ss)))) return (error); } if (nss == NULL) return (0); error = copyin(nss, &ss, sizeof(ss)); if (error) return (error); if (onstack) return (EPERM); if (ss.ss_flags & ~SS_DISABLE) return (EINVAL); if (ss.ss_flags & SS_DISABLE) { p->p_sigstk.ss_flags = ss.ss_flags; return (0); } if (ss.ss_size < MINSIGSTKSZ) return (ENOMEM); error = uvm_map_remap_as_stack(p, (vaddr_t)ss.ss_sp, ss.ss_size); if (error) return (error); p->p_sigstk = ss; return (0); } int sys_kill(struct proc *cp, void *v, register_t *retval) { struct sys_kill_args /* { syscallarg(int) pid; syscallarg(int) signum; } */ *uap = v; struct process *pr; int pid = SCARG(uap, pid); int signum = SCARG(uap, signum); int error; int zombie = 0; if ((error = pledge_kill(cp, pid)) != 0) return (error); if (((u_int)signum) >= NSIG) return (EINVAL); if (pid > 0) { if ((pr = prfind(pid)) == NULL) { if ((pr = zombiefind(pid)) == NULL) return (ESRCH); else zombie = 1; } if (!cansignal(cp, pr, signum)) return (EPERM); /* kill single process */ if (signum && !zombie) prsignal(pr, signum); return (0); } switch (pid) { case -1: /* broadcast signal */ return (killpg1(cp, signum, 0, 1)); case 0: /* signal own process group */ return (killpg1(cp, signum, 0, 0)); default: /* negative explicit process group */ return (killpg1(cp, signum, -pid, 0)); } } int sys_thrkill(struct proc *cp, void *v, register_t *retval) { struct sys_thrkill_args /* { syscallarg(pid_t) tid; syscallarg(int) signum; syscallarg(void *) tcb; } */ *uap = v; struct proc *p; int tid = SCARG(uap, tid); int signum = SCARG(uap, signum); void *tcb; if (((u_int)signum) >= NSIG) return (EINVAL); p = tid ? tfind_user(tid, cp->p_p) : cp; if (p == NULL) return (ESRCH); /* optionally require the target thread to have the given tcb addr */ tcb = SCARG(uap, tcb); if (tcb != NULL && tcb != TCB_GET(p)) return (ESRCH); if (signum) ptsignal(p, signum, STHREAD); return (0); } /* * Common code for kill process group/broadcast kill. * cp is calling process. */ int killpg1(struct proc *cp, int signum, int pgid, int all) { struct process *pr; struct pgrp *pgrp; int nfound = 0; if (all) { /* * broadcast */ LIST_FOREACH(pr, &allprocess, ps_list) { if (pr->ps_pid <= 1 || pr->ps_flags & (PS_SYSTEM | PS_NOBROADCASTKILL) || pr == cp->p_p || !cansignal(cp, pr, signum)) continue; nfound++; if (signum) prsignal(pr, signum); } } else { if (pgid == 0) /* * zero pgid means send to my process group. */ pgrp = cp->p_p->ps_pgrp; else { pgrp = pgfind(pgid); if (pgrp == NULL) return (ESRCH); } LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) { if (pr->ps_pid <= 1 || pr->ps_flags & PS_SYSTEM || !cansignal(cp, pr, signum)) continue; nfound++; if (signum) prsignal(pr, signum); } } return (nfound ? 0 : ESRCH); } #define CANDELIVER(uid, euid, pr) \ (euid == 0 || \ (uid) == (pr)->ps_ucred->cr_ruid || \ (uid) == (pr)->ps_ucred->cr_svuid || \ (uid) == (pr)->ps_ucred->cr_uid || \ (euid) == (pr)->ps_ucred->cr_ruid || \ (euid) == (pr)->ps_ucred->cr_svuid || \ (euid) == (pr)->ps_ucred->cr_uid) #define CANSIGIO(cr, pr) \ CANDELIVER((cr)->cr_ruid, (cr)->cr_uid, (pr)) /* * 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 signum, int checkctty) { struct process *pr; if (pgrp) LIST_FOREACH(pr, &pgrp->pg_members, ps_pglist) if (checkctty == 0 || pr->ps_flags & PS_CONTROLT) prsignal(pr, signum); } /* * 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_ref *sir, int sig, int checkctty) { struct process *pr; struct sigio *sigio; if (sir->sir_sigio == NULL) return; KERNEL_LOCK(); mtx_enter(&sigio_lock); sigio = sir->sir_sigio; if (sigio == NULL) goto out; if (sigio->sio_pgid > 0) { if (CANSIGIO(sigio->sio_ucred, sigio->sio_proc)) prsignal(sigio->sio_proc, sig); } else if (sigio->sio_pgid < 0) { LIST_FOREACH(pr, &sigio->sio_pgrp->pg_members, ps_pglist) { if (CANSIGIO(sigio->sio_ucred, pr) && (checkctty == 0 || (pr->ps_flags & PS_CONTROLT))) prsignal(pr, sig); } } out: mtx_leave(&sigio_lock); KERNEL_UNLOCK(); } /* * Recalculate the signal mask and reset the signal disposition after * usermode frame for delivery is formed. */ void postsig_done(struct proc *p, int signum, sigset_t catchmask, int reset) { p->p_ru.ru_nsignals++; atomic_setbits_int(&p->p_sigmask, catchmask); if (reset != 0) { sigset_t mask = sigmask(signum); struct sigacts *ps = p->p_p->ps_sigacts; mtx_enter(&p->p_p->ps_mtx); ps->ps_sigcatch &= ~mask; if (signum != SIGCONT && sigprop[signum] & SA_IGNORE) ps->ps_sigignore |= mask; ps->ps_sigact[signum] = SIG_DFL; mtx_leave(&p->p_p->ps_mtx); } } /* * 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 proc *p, int signum, u_long trapno, int code, union sigval sigval) { struct process *pr = p->p_p; struct sigctx ctx; int mask; switch (signum) { case SIGILL: case SIGBUS: case SIGSEGV: pr->ps_acflag |= ATRAP; break; } mask = sigmask(signum); setsigctx(p, signum, &ctx); if ((pr->ps_flags & PS_TRACED) == 0 && ctx.sig_catch != 0 && (p->p_sigmask & mask) == 0) { siginfo_t si; initsiginfo(&si, signum, trapno, code, sigval); #ifdef KTRACE if (KTRPOINT(p, KTR_PSIG)) { ktrpsig(p, signum, ctx.sig_action, p->p_sigmask, code, &si); } #endif if (sendsig(ctx.sig_action, signum, p->p_sigmask, &si, ctx.sig_info, ctx.sig_onstack)) { KERNEL_LOCK(); sigexit(p, SIGILL); /* NOTREACHED */ } postsig_done(p, signum, ctx.sig_catchmask, ctx.sig_reset); } else { p->p_sisig = signum; p->p_sitrapno = trapno; /* XXX for core dump/debugger */ p->p_sicode = code; p->p_sigval = sigval; /* * If traced, stop if signal is masked, and stay stopped * until released by the debugger. If our parent process * is waiting for us, don't hang as we could deadlock. */ if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && signum != SIGKILL && (p->p_sigmask & mask) != 0) { int s; single_thread_set(p, SINGLE_SUSPEND | SINGLE_NOWAIT); pr->ps_xsig = signum; SCHED_LOCK(s); proc_stop(p, 1); SCHED_UNLOCK(s); signum = pr->ps_xsig; single_thread_clear(p, 0); /* * If we are no longer being traced, or the parent * didn't give us a signal, skip sending the signal. */ if ((pr->ps_flags & PS_TRACED) == 0 || signum == 0) return; /* update signal info */ p->p_sisig = signum; mask = sigmask(signum); } /* * Signals like SIGBUS and SIGSEGV should not, when * generated by the kernel, be ignorable or blockable. * If it is and we're not being traced, then just kill * the process. * After vfs_shutdown(9), init(8) cannot receive signals * because new code pages of the signal handler cannot be * mapped from halted storage. init(8) may not die or the * kernel panics. Better loop between signal handler and * page fault trap until the machine is halted. */ if ((pr->ps_flags & PS_TRACED) == 0 && (sigprop[signum] & SA_KILL) && ((p->p_sigmask & mask) || ctx.sig_ignore) && pr->ps_pid != 1) { KERNEL_LOCK(); sigexit(p, signum); /* NOTREACHED */ } KERNEL_LOCK(); ptsignal(p, signum, STHREAD); KERNEL_UNLOCK(); } } /* * Send the signal to the process. If the signal has an action, the action * is usually performed by the target process rather than the caller; we add * the signal to the set of pending signals for the process. * * Exceptions: * o When a stop signal is sent to a sleeping process that takes the * default action, the process is stopped without awakening it. * o SIGCONT restarts stopped processes (or puts them back to sleep) * regardless of the signal action (eg, blocked or ignored). * * Other ignored signals are discarded immediately. */ void psignal(struct proc *p, int signum) { ptsignal(p, signum, SPROCESS); } /* * type = SPROCESS process signal, can be diverted (sigwait()) * type = STHREAD thread signal, but should be propagated if unhandled * type = SPROPAGATED propagated to this thread, so don't propagate again */ void ptsignal(struct proc *p, int signum, enum signal_type type) { int s, prop; sig_t action; int mask; int *siglist; struct process *pr = p->p_p; struct proc *q; int wakeparent = 0; KERNEL_ASSERT_LOCKED(); #ifdef DIAGNOSTIC if ((u_int)signum >= NSIG || signum == 0) panic("psignal signal number"); #endif /* Ignore signal if the target process is exiting */ if (pr->ps_flags & PS_EXITING) return; mask = sigmask(signum); if (type == SPROCESS) { /* Accept SIGKILL to coredumping processes */ if (pr->ps_flags & PS_COREDUMP && signum == SIGKILL) { atomic_setbits_int(&pr->ps_siglist, mask); return; } /* * If the current thread can process the signal * immediately (it's unblocked) then have it take it. */ q = curproc; if (q != NULL && q->p_p == pr && (q->p_flag & P_WEXIT) == 0 && (q->p_sigmask & mask) == 0) p = q; else { /* * A process-wide signal can be diverted to a * different thread that's in sigwait() for this * signal. If there isn't such a thread, then * pick a thread that doesn't have it blocked so * that the stop/kill consideration isn't * delayed. Otherwise, mark it pending on the * main thread. */ TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { /* ignore exiting threads */ if (q->p_flag & P_WEXIT) continue; /* skip threads that have the signal blocked */ if ((q->p_sigmask & mask) != 0) continue; /* okay, could send to this thread */ p = q; /* * sigsuspend, sigwait, ppoll/pselect, etc? * Definitely go to this thread, as it's * already blocked in the kernel. */ if (q->p_flag & P_SIGSUSPEND) break; } } } if (type != SPROPAGATED) knote_locked(&pr->ps_klist, NOTE_SIGNAL | signum); prop = sigprop[signum]; /* * If proc is traced, always give parent a chance. */ if (pr->ps_flags & PS_TRACED) { action = SIG_DFL; } else { sigset_t sigcatch, sigignore; /* * If the signal is being ignored, * then we forget about it immediately. * (Note: we don't set SIGCONT in ps_sigignore, * and if it is set to SIG_IGN, * action will be SIG_DFL here.) */ mtx_enter(&pr->ps_mtx); sigignore = pr->ps_sigacts->ps_sigignore; sigcatch = pr->ps_sigacts->ps_sigcatch; mtx_leave(&pr->ps_mtx); if (sigignore & mask) return; if (p->p_sigmask & mask) { action = SIG_HOLD; } else if (sigcatch & mask) { action = SIG_CATCH; } else { action = SIG_DFL; if (prop & SA_KILL && pr->ps_nice > NZERO) pr->ps_nice = NZERO; /* * If sending a tty stop signal to a member of an * orphaned process group, discard the signal here if * the action is default; don't stop the process below * if sleeping, and don't clear any pending SIGCONT. */ if (prop & SA_TTYSTOP && pr->ps_pgrp->pg_jobc == 0) return; } } /* * If delivered to process, mark as pending there. Continue and stop * signals will be propagated to all threads. So they are always * marked at thread level. */ siglist = (type == SPROCESS) ? &pr->ps_siglist : &p->p_siglist; if (prop & SA_CONT) { siglist = &p->p_siglist; atomic_clearbits_int(siglist, STOPSIGMASK); } if (prop & SA_STOP) { siglist = &p->p_siglist; atomic_clearbits_int(siglist, CONTSIGMASK); atomic_clearbits_int(&p->p_flag, P_CONTINUED); } /* * XXX delay processing of SA_STOP signals unless action == SIG_DFL? */ if (prop & (SA_CONT | SA_STOP) && type != SPROPAGATED) TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) if (q != p) ptsignal(q, signum, SPROPAGATED); /* * Defer further processing for signals which are held, * except that stopped processes must be continued by SIGCONT. */ if (action == SIG_HOLD && ((prop & SA_CONT) == 0 || p->p_stat != SSTOP)) { atomic_setbits_int(siglist, mask); return; } SCHED_LOCK(s); switch (p->p_stat) { case SSLEEP: /* * If process is sleeping uninterruptibly * we can't interrupt the sleep... the signal will * be noticed when the process returns through * trap() or syscall(). */ if ((p->p_flag & P_SINTR) == 0) goto out; /* * Process is sleeping and traced... make it runnable * so it can discover the signal in cursig() and stop * for the parent. */ if (pr->ps_flags & PS_TRACED) goto run; /* * If SIGCONT is default (or ignored) and process is * asleep, we are finished; the process should not * be awakened. */ if ((prop & SA_CONT) && action == SIG_DFL) { mask = 0; goto out; } /* * When a sleeping process receives a stop * signal, process immediately if possible. */ if ((prop & SA_STOP) && action == SIG_DFL) { /* * If a child holding parent blocked, * stopping could cause deadlock. */ if (pr->ps_flags & PS_PPWAIT) goto out; mask = 0; pr->ps_xsig = signum; proc_stop(p, 0); goto out; } /* * All other (caught or default) signals * cause the process to run. */ goto runfast; /* NOTREACHED */ case SSTOP: /* * If traced process is already stopped, * then no further action is necessary. */ if (pr->ps_flags & PS_TRACED) goto out; /* * Kill signal always sets processes running. */ if (signum == SIGKILL) { atomic_clearbits_int(&p->p_flag, P_SUSPSIG); goto runfast; } 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. If it isn't waiting on * an event, then it goes back to run state. * Otherwise, process goes back to sleep state. */ atomic_setbits_int(&p->p_flag, P_CONTINUED); atomic_clearbits_int(&p->p_flag, P_SUSPSIG); wakeparent = 1; if (action == SIG_DFL) atomic_clearbits_int(siglist, mask); if (action == SIG_CATCH) goto runfast; if (p->p_wchan == NULL) goto run; atomic_clearbits_int(&p->p_flag, P_WSLEEP); p->p_stat = SSLEEP; goto out; } if (prop & SA_STOP) { /* * Already stopped, don't need to stop again. * (If we did the shell could get confused.) */ mask = 0; goto out; } /* * If process is sleeping interruptibly, then simulate a * wakeup so that when it is continued, it will be made * runnable and can look at the signal. But don't make * the process runnable, leave it stopped. */ if (p->p_flag & P_SINTR) unsleep(p); goto out; case SONPROC: /* set siglist before issuing the ast */ atomic_setbits_int(siglist, mask); mask = 0; signotify(p); /* FALLTHROUGH */ default: /* * SRUN, SIDL, SDEAD do nothing with the signal, * other than kicking ourselves if we are running. * It will either never be noticed, or noticed very soon. */ goto out; } /* NOTREACHED */ runfast: /* * Raise priority to at least PUSER. */ if (p->p_usrpri > PUSER) p->p_usrpri = PUSER; run: setrunnable(p); out: /* finally adjust siglist */ if (mask) atomic_setbits_int(siglist, mask); SCHED_UNLOCK(s); if (wakeparent) wakeup(pr->ps_pptr); } /* fill the signal context which should be used by postsig() and issignal() */ void setsigctx(struct proc *p, int signum, struct sigctx *sctx) { struct sigacts *ps = p->p_p->ps_sigacts; sigset_t mask; mtx_enter(&p->p_p->ps_mtx); mask = sigmask(signum); sctx->sig_action = ps->ps_sigact[signum]; sctx->sig_catchmask = ps->ps_catchmask[signum]; sctx->sig_reset = (ps->ps_sigreset & mask) != 0; sctx->sig_info = (ps->ps_siginfo & mask) != 0; sctx->sig_intr = (ps->ps_sigintr & mask) != 0; sctx->sig_onstack = (ps->ps_sigonstack & mask) != 0; sctx->sig_ignore = (ps->ps_sigignore & mask) != 0; sctx->sig_catch = (ps->ps_sigcatch & mask) != 0; mtx_leave(&p->p_p->ps_mtx); } /* * Determine signal that should be delivered to process p, the current * process, 0 if none. * * 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. The normal call sequence is * * while (signum = cursig(curproc, &ctx)) * postsig(signum, &ctx); * * Assumes that if the P_SINTR flag is set, we're holding both the * kernel and scheduler locks. */ int cursig(struct proc *p, struct sigctx *sctx) { struct process *pr = p->p_p; int signum, mask, prop; sigset_t ps_siglist; int s; KASSERT(p == curproc); for (;;) { ps_siglist = READ_ONCE(pr->ps_siglist); membar_consumer(); mask = SIGPENDING(p); if (pr->ps_flags & PS_PPWAIT) mask &= ~STOPSIGMASK; if (mask == 0) /* no signal to send */ return (0); signum = ffs((long)mask); mask = sigmask(signum); /* take the signal! */ if (atomic_cas_uint(&pr->ps_siglist, ps_siglist, ps_siglist & ~mask) != ps_siglist) { /* lost race taking the process signal, restart */ continue; } atomic_clearbits_int(&p->p_siglist, mask); setsigctx(p, signum, sctx); /* * We should see pending but ignored signals * only if PS_TRACED was on when they were posted. */ if (sctx->sig_ignore && (pr->ps_flags & PS_TRACED) == 0) continue; /* * If traced, always stop, and stay stopped until released * by the debugger. If our parent process is waiting for * us, don't hang as we could deadlock. */ if (((pr->ps_flags & (PS_TRACED | PS_PPWAIT)) == PS_TRACED) && signum != SIGKILL) { single_thread_set(p, SINGLE_SUSPEND | SINGLE_NOWAIT); pr->ps_xsig = signum; SCHED_LOCK(s); proc_stop(p, 1); SCHED_UNLOCK(s); /* * re-take the signal before releasing * the other threads. Must check the continue * conditions below and only take the signal if * those are not true. */ signum = pr->ps_xsig; mask = sigmask(signum); setsigctx(p, signum, sctx); if (!((pr->ps_flags & PS_TRACED) == 0 || signum == 0 || (p->p_sigmask & mask) != 0)) { atomic_clearbits_int(&p->p_siglist, mask); atomic_clearbits_int(&pr->ps_siglist, mask); } single_thread_clear(p, 0); /* * If we are no longer being traced, or the parent * didn't give us a signal, look for more signals. */ if ((pr->ps_flags & PS_TRACED) == 0 || signum == 0) continue; /* * If the new signal is being masked, look for other * signals. */ if ((p->p_sigmask & mask) != 0) continue; } prop = sigprop[signum]; /* * Decide whether the signal should be returned. * Return the signal's number, or fall through * to clear it from the pending mask. */ switch ((long)sctx->sig_action) { case (long)SIG_DFL: /* * Don't take default actions on system processes. */ if (pr->ps_pid <= 1) { #ifdef DIAGNOSTIC /* * Are you sure you want to ignore SIGSEGV * in init? XXX */ printf("Process (pid %d) got signal" " %d\n", pr->ps_pid, signum); #endif break; /* == ignore */ } /* * If there is a pending stop signal to process * with default action, stop here, * then clear the signal. However, * if process is member of an orphaned * process group, ignore tty stop signals. */ if (prop & SA_STOP) { if (pr->ps_flags & PS_TRACED || (pr->ps_pgrp->pg_jobc == 0 && prop & SA_TTYSTOP)) break; /* == ignore */ pr->ps_xsig = signum; SCHED_LOCK(s); proc_stop(p, 1); SCHED_UNLOCK(s); break; } else if (prop & SA_IGNORE) { /* * Except for SIGCONT, shouldn't get here. * Default action is to ignore; drop it. */ break; /* == ignore */ } else goto keep; /* NOTREACHED */ case (long)SIG_IGN: /* * Masking above should prevent us ever trying * to take action on an ignored signal other * than SIGCONT, unless process is traced. */ if ((prop & SA_CONT) == 0 && (pr->ps_flags & PS_TRACED) == 0) printf("%s\n", __func__); break; /* == ignore */ default: /* * This signal has an action, let * postsig() process it. */ goto keep; } } /* NOTREACHED */ keep: atomic_setbits_int(&p->p_siglist, mask); /*leave the signal for later */ return (signum); } /* * Put the argument process into the stopped state and notify the parent * via wakeup. Signals are handled elsewhere. The process must not be * on the run queue. */ void proc_stop(struct proc *p, int sw) { struct process *pr = p->p_p; #ifdef MULTIPROCESSOR SCHED_ASSERT_LOCKED(); #endif p->p_stat = SSTOP; atomic_clearbits_int(&pr->ps_flags, PS_WAITED); atomic_setbits_int(&pr->ps_flags, PS_STOPPED); atomic_setbits_int(&p->p_flag, P_SUSPSIG); /* * We need this soft interrupt to be handled fast. * Extra calls to softclock don't hurt. */ softintr_schedule(proc_stop_si); if (sw) mi_switch(); } /* * Called from a soft interrupt to send signals to the parents of stopped * processes. * We can't do this in proc_stop because it's called with nasty locks held * and we would need recursive scheduler lock to deal with that. */ void proc_stop_sweep(void *v) { struct process *pr; LIST_FOREACH(pr, &allprocess, ps_list) { if ((pr->ps_flags & PS_STOPPED) == 0) continue; atomic_clearbits_int(&pr->ps_flags, PS_STOPPED); if ((pr->ps_pptr->ps_sigacts->ps_sigflags & SAS_NOCLDSTOP) == 0) prsignal(pr->ps_pptr, SIGCHLD); wakeup(pr->ps_pptr); } } /* * Take the action for the specified signal * from the current set of pending signals. */ void postsig(struct proc *p, int signum, struct sigctx *sctx) { u_long trapno; int mask, returnmask; siginfo_t si; union sigval sigval; int code; KASSERT(signum != 0); mask = sigmask(signum); atomic_clearbits_int(&p->p_siglist, mask); sigval.sival_ptr = NULL; if (p->p_sisig != signum) { trapno = 0; code = SI_USER; sigval.sival_ptr = NULL; } else { trapno = p->p_sitrapno; code = p->p_sicode; sigval = p->p_sigval; } initsiginfo(&si, signum, trapno, code, sigval); #ifdef KTRACE if (KTRPOINT(p, KTR_PSIG)) { ktrpsig(p, signum, sctx->sig_action, p->p_flag & P_SIGSUSPEND ? p->p_oldmask : p->p_sigmask, code, &si); } #endif if (sctx->sig_action == SIG_DFL) { /* * Default action, where the default is to kill * the process. (Other cases were ignored above.) */ KERNEL_LOCK(); sigexit(p, signum); /* NOTREACHED */ } else { /* * If we get here, the signal must be caught. */ #ifdef DIAGNOSTIC if (sctx->sig_action == SIG_IGN || (p->p_sigmask & mask)) panic("postsig action"); #endif /* * Set the new mask value and also defer further * occurrences of this signal. * * Special case: user has done a sigpause. Here the * current mask is not of interest, but rather the * mask from before the sigpause is what we want * restored after the signal processing is completed. */ if (p->p_flag & P_SIGSUSPEND) { atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); returnmask = p->p_oldmask; } else { returnmask = p->p_sigmask; } if (p->p_sisig == signum) { p->p_sisig = 0; p->p_sitrapno = 0; p->p_sicode = SI_USER; p->p_sigval.sival_ptr = NULL; } if (sendsig(sctx->sig_action, signum, returnmask, &si, sctx->sig_info, sctx->sig_onstack)) { KERNEL_LOCK(); sigexit(p, SIGILL); /* NOTREACHED */ } postsig_done(p, signum, sctx->sig_catchmask, sctx->sig_reset); } } /* * 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 proc *p, int signum) { /* Mark process as going away */ atomic_setbits_int(&p->p_flag, P_WEXIT); p->p_p->ps_acflag |= AXSIG; if (sigprop[signum] & SA_CORE) { p->p_sisig = signum; /* if there are other threads, pause them */ if (P_HASSIBLING(p)) single_thread_set(p, SINGLE_UNWIND); if (coredump(p) == 0) signum |= WCOREFLAG; } exit1(p, 0, signum, EXIT_NORMAL); /* NOTREACHED */ } /* * Send uncatchable SIGABRT for coredump. */ void sigabort(struct proc *p) { struct sigaction sa; memset(&sa, 0, sizeof sa); sa.sa_handler = SIG_DFL; setsigvec(p, SIGABRT, &sa); atomic_clearbits_int(&p->p_sigmask, sigmask(SIGABRT)); psignal(p, SIGABRT); } /* * Return 1 if `sig', a given signal, is ignored or masked for `p', a given * thread, and 0 otherwise. */ int sigismasked(struct proc *p, int sig) { struct process *pr = p->p_p; int rv; mtx_enter(&pr->ps_mtx); rv = (pr->ps_sigacts->ps_sigignore & sigmask(sig)) || (p->p_sigmask & sigmask(sig)); mtx_leave(&pr->ps_mtx); return !!rv; } struct coredump_iostate { struct proc *io_proc; struct vnode *io_vp; struct ucred *io_cred; off_t io_offset; }; /* * Dump core, into a file named "progname.core", unless the process was * setuid/setgid. */ int coredump(struct proc *p) { #ifdef SMALL_KERNEL return EPERM; #else struct process *pr = p->p_p; struct vnode *vp; struct ucred *cred = p->p_ucred; struct vmspace *vm = p->p_vmspace; struct nameidata nd; struct vattr vattr; struct coredump_iostate io; int error, len, incrash = 0; char *name; const char *dir = "/var/crash"; atomic_setbits_int(&pr->ps_flags, PS_COREDUMP); #ifdef PMAP_CHECK_COPYIN /* disable copyin checks, so we can write out text sections if needed */ p->p_vmspace->vm_map.check_copyin_count = 0; #endif /* Don't dump if will exceed file size limit. */ if (USPACE + ptoa(vm->vm_dsize + vm->vm_ssize) >= lim_cur(RLIMIT_CORE)) return (EFBIG); name = pool_get(&namei_pool, PR_WAITOK); /* * If the process has inconsistent uids, nosuidcoredump * determines coredump placement policy. */ if (((pr->ps_flags & PS_SUGID) && (error = suser(p))) || ((pr->ps_flags & PS_SUGID) && nosuidcoredump)) { if (nosuidcoredump == 3) { /* * If the program directory does not exist, dumps of * that core will silently fail. */ len = snprintf(name, MAXPATHLEN, "%s/%s/%u.core", dir, pr->ps_comm, pr->ps_pid); incrash = KERNELPATH; } else if (nosuidcoredump == 2) { len = snprintf(name, MAXPATHLEN, "%s/%s.core", dir, pr->ps_comm); incrash = KERNELPATH; } else { pool_put(&namei_pool, name); return (EPERM); } } else len = snprintf(name, MAXPATHLEN, "%s.core", pr->ps_comm); if (len >= MAXPATHLEN) { pool_put(&namei_pool, name); return (EACCES); } /* * Control the UID used to write out. The normal case uses * the real UID. If the sugid case is going to write into the * controlled directory, we do so as root. */ if (incrash == 0) { cred = crdup(cred); cred->cr_uid = cred->cr_ruid; cred->cr_gid = cred->cr_rgid; } else { if (p->p_fd->fd_rdir) { vrele(p->p_fd->fd_rdir); p->p_fd->fd_rdir = NULL; } p->p_ucred = crdup(p->p_ucred); crfree(cred); cred = p->p_ucred; crhold(cred); cred->cr_uid = 0; cred->cr_gid = 0; } /* incrash should be 0 or KERNELPATH only */ NDINIT(&nd, 0, BYPASSUNVEIL | incrash, UIO_SYSSPACE, name, p); error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW | O_NONBLOCK, S_IRUSR | S_IWUSR); if (error) goto out; /* * Don't dump to non-regular files, files with links, or files * owned by someone else. */ vp = nd.ni_vp; if ((error = VOP_GETATTR(vp, &vattr, cred, p)) != 0) { VOP_UNLOCK(vp); vn_close(vp, FWRITE, cred, p); goto out; } if (vp->v_type != VREG || vattr.va_nlink != 1 || vattr.va_mode & ((VREAD | VWRITE) >> 3 | (VREAD | VWRITE) >> 6) || vattr.va_uid != cred->cr_uid) { error = EACCES; VOP_UNLOCK(vp); vn_close(vp, FWRITE, cred, p); goto out; } VATTR_NULL(&vattr); vattr.va_size = 0; VOP_SETATTR(vp, &vattr, cred, p); pr->ps_acflag |= ACORE; io.io_proc = p; io.io_vp = vp; io.io_cred = cred; io.io_offset = 0; VOP_UNLOCK(vp); vref(vp); error = vn_close(vp, FWRITE, cred, p); if (error == 0) error = coredump_elf(p, &io); vrele(vp); out: crfree(cred); pool_put(&namei_pool, name); return (error); #endif } #ifndef SMALL_KERNEL int coredump_write(void *cookie, enum uio_seg segflg, const void *data, size_t len) { struct coredump_iostate *io = cookie; off_t coffset = 0; size_t csize; int chunk, error; csize = len; do { if (sigmask(SIGKILL) & (io->io_proc->p_siglist | io->io_proc->p_p->ps_siglist)) return (EINTR); /* Rest of the loop sleeps with lock held, so... */ yield(); chunk = MIN(csize, MAXPHYS); error = vn_rdwr(UIO_WRITE, io->io_vp, (caddr_t)data + coffset, chunk, io->io_offset + coffset, segflg, IO_UNIT, io->io_cred, NULL, io->io_proc); if (error) { struct process *pr = io->io_proc->p_p; if (error == ENOSPC) log(LOG_ERR, "coredump of %s(%d) failed, filesystem full\n", pr->ps_comm, pr->ps_pid); else log(LOG_ERR, "coredump of %s(%d), write failed: errno %d\n", pr->ps_comm, pr->ps_pid, error); return (error); } coffset += chunk; csize -= chunk; } while (csize > 0); io->io_offset += len; return (0); } void coredump_unmap(void *cookie, vaddr_t start, vaddr_t end) { struct coredump_iostate *io = cookie; uvm_unmap(&io->io_proc->p_vmspace->vm_map, start, end); } #endif /* !SMALL_KERNEL */ /* * Nonexistent system call-- signal process (may want to handle it). * Flag error in case process won't see signal immediately (blocked or ignored). */ int sys_nosys(struct proc *p, void *v, register_t *retval) { ptsignal(p, SIGSYS, STHREAD); return (ENOSYS); } int sys___thrsigdivert(struct proc *p, void *v, register_t *retval) { struct sys___thrsigdivert_args /* { syscallarg(sigset_t) sigmask; syscallarg(siginfo_t *) info; syscallarg(const struct timespec *) timeout; } */ *uap = v; struct sigctx ctx; sigset_t mask = SCARG(uap, sigmask) &~ sigcantmask; siginfo_t si; uint64_t nsecs = INFSLP; int timeinvalid = 0; int error = 0; memset(&si, 0, sizeof(si)); if (SCARG(uap, timeout) != NULL) { struct timespec ts; if ((error = copyin(SCARG(uap, timeout), &ts, sizeof(ts))) != 0) return (error); #ifdef KTRACE if (KTRPOINT(p, KTR_STRUCT)) ktrreltimespec(p, &ts); #endif if (!timespecisvalid(&ts)) timeinvalid = 1; else nsecs = TIMESPEC_TO_NSEC(&ts); } dosigsuspend(p, p->p_sigmask &~ mask); for (;;) { si.si_signo = cursig(p, &ctx); if (si.si_signo != 0) { sigset_t smask = sigmask(si.si_signo); if (smask & mask) { atomic_clearbits_int(&p->p_siglist, smask); error = 0; break; } } /* per-POSIX, delay this error until after the above */ if (timeinvalid) error = EINVAL; /* per-POSIX, return immediately if timeout is zero-valued */ if (nsecs == 0) error = EAGAIN; if (error != 0) break; error = tsleep_nsec(&nowake, PPAUSE|PCATCH, "sigwait", nsecs); } if (error == 0) { *retval = si.si_signo; if (SCARG(uap, info) != NULL) { error = copyout(&si, SCARG(uap, info), sizeof(si)); #ifdef KTRACE if (error == 0 && KTRPOINT(p, KTR_STRUCT)) ktrsiginfo(p, &si); #endif } } else if (error == ERESTART && SCARG(uap, timeout) != NULL) { /* * Restarting is wrong if there's a timeout, as it'll be * for the same interval again */ error = EINTR; } return (error); } void initsiginfo(siginfo_t *si, int sig, u_long trapno, int code, union sigval val) { memset(si, 0, sizeof(*si)); si->si_signo = sig; si->si_code = code; if (code == SI_USER) { si->si_value = val; } else { switch (sig) { case SIGSEGV: case SIGILL: case SIGBUS: case SIGFPE: si->si_addr = val.sival_ptr; si->si_trapno = trapno; break; case SIGXFSZ: break; } } } int filt_sigattach(struct knote *kn) { struct process *pr = curproc->p_p; int s; if (kn->kn_id >= NSIG) return EINVAL; kn->kn_ptr.p_process = pr; kn->kn_flags |= EV_CLEAR; /* automatically set */ s = splhigh(); klist_insert_locked(&pr->ps_klist, kn); splx(s); return (0); } void filt_sigdetach(struct knote *kn) { struct process *pr = kn->kn_ptr.p_process; int s; s = splhigh(); klist_remove_locked(&pr->ps_klist, kn); splx(s); } /* * 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. */ 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); } void userret(struct proc *p) { struct sigctx ctx; int signum; if (p->p_flag & P_SUSPSINGLE) single_thread_check(p, 0); /* send SIGPROF or SIGVTALRM if their timers interrupted this thread */ if (p->p_flag & P_PROFPEND) { atomic_clearbits_int(&p->p_flag, P_PROFPEND); KERNEL_LOCK(); psignal(p, SIGPROF); KERNEL_UNLOCK(); } if (p->p_flag & P_ALRMPEND) { atomic_clearbits_int(&p->p_flag, P_ALRMPEND); KERNEL_LOCK(); psignal(p, SIGVTALRM); KERNEL_UNLOCK(); } if (SIGPENDING(p) != 0) { while ((signum = cursig(p, &ctx)) != 0) postsig(p, signum, &ctx); } /* * If P_SIGSUSPEND is still set here, then we still need to restore * the original sigmask before returning to userspace. Also, this * might unmask some pending signals, so we need to check a second * time for signals to post. */ if (p->p_flag & P_SIGSUSPEND) { atomic_clearbits_int(&p->p_flag, P_SIGSUSPEND); p->p_sigmask = p->p_oldmask; while ((signum = cursig(p, &ctx)) != 0) postsig(p, signum, &ctx); } WITNESS_WARN(WARN_PANIC, NULL, "userret: returning"); p->p_cpu->ci_schedstate.spc_curpriority = p->p_usrpri; } int single_thread_check_locked(struct proc *p, int deep, int s) { struct process *pr = p->p_p; SCHED_ASSERT_LOCKED(); if (pr->ps_single == NULL || pr->ps_single == p) return (0); do { /* if we're in deep, we need to unwind to the edge */ if (deep) { if (pr->ps_flags & PS_SINGLEUNWIND) return (ERESTART); if (pr->ps_flags & PS_SINGLEEXIT) return (EINTR); } if (atomic_dec_int_nv(&pr->ps_singlecount) == 0) wakeup(&pr->ps_singlecount); if (pr->ps_flags & PS_SINGLEEXIT) { SCHED_UNLOCK(s); KERNEL_LOCK(); exit1(p, 0, 0, EXIT_THREAD_NOCHECK); /* NOTREACHED */ } /* not exiting and don't need to unwind, so suspend */ p->p_stat = SSTOP; mi_switch(); } while (pr->ps_single != NULL); return (0); } int single_thread_check(struct proc *p, int deep) { int s, error; SCHED_LOCK(s); error = single_thread_check_locked(p, deep, s); SCHED_UNLOCK(s); return error; } /* * Stop other threads in the process. The mode controls how and * where the other threads should stop: * - SINGLE_SUSPEND: stop wherever they are, will later be released (via * single_thread_clear()) * - SINGLE_UNWIND: just unwind to kernel boundary, will be told to exit * (by setting to SINGLE_EXIT) or released as with SINGLE_SUSPEND * - SINGLE_EXIT: unwind to kernel boundary and exit */ int single_thread_set(struct proc *p, int flags) { struct process *pr = p->p_p; struct proc *q; int error, s, mode = flags & SINGLE_MASK; KASSERT(curproc == p); SCHED_LOCK(s); error = single_thread_check_locked(p, flags & SINGLE_DEEP, s); if (error) { SCHED_UNLOCK(s); return error; } switch (mode) { case SINGLE_SUSPEND: break; case SINGLE_UNWIND: atomic_setbits_int(&pr->ps_flags, PS_SINGLEUNWIND); break; case SINGLE_EXIT: atomic_setbits_int(&pr->ps_flags, PS_SINGLEEXIT); atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND); break; #ifdef DIAGNOSTIC default: panic("single_thread_mode = %d", mode); #endif } pr->ps_singlecount = 0; membar_producer(); pr->ps_single = p; TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { if (q == p) continue; if (q->p_flag & P_WEXIT) { if (mode == SINGLE_EXIT) { if (q->p_stat == SSTOP) { setrunnable(q); atomic_inc_int(&pr->ps_singlecount); } } continue; } atomic_setbits_int(&q->p_flag, P_SUSPSINGLE); switch (q->p_stat) { case SIDL: case SRUN: atomic_inc_int(&pr->ps_singlecount); break; case SSLEEP: /* if it's not interruptible, then just have to wait */ if (q->p_flag & P_SINTR) { /* merely need to suspend? just stop it */ if (mode == SINGLE_SUSPEND) { q->p_stat = SSTOP; break; } /* need to unwind or exit, so wake it */ setrunnable(q); } atomic_inc_int(&pr->ps_singlecount); break; case SSTOP: if (mode == SINGLE_EXIT) { setrunnable(q); atomic_inc_int(&pr->ps_singlecount); } break; case SDEAD: break; case SONPROC: atomic_inc_int(&pr->ps_singlecount); signotify(q); break; } } SCHED_UNLOCK(s); if ((flags & SINGLE_NOWAIT) == 0) single_thread_wait(pr, 1); return 0; } /* * Wait for other threads to stop. If recheck is false then the function * returns non-zero if the caller needs to restart the check else 0 is * returned. If recheck is true the return value is always 0. */ int single_thread_wait(struct process *pr, int recheck) { int wait; /* wait until they're all suspended */ wait = pr->ps_singlecount > 0; while (wait) { sleep_setup(&pr->ps_singlecount, PWAIT, "suspend"); wait = pr->ps_singlecount > 0; sleep_finish(0, wait); if (!recheck) break; } return wait; } void single_thread_clear(struct proc *p, int flag) { struct process *pr = p->p_p; struct proc *q; int s; KASSERT(pr->ps_single == p); KASSERT(curproc == p); SCHED_LOCK(s); pr->ps_single = NULL; atomic_clearbits_int(&pr->ps_flags, PS_SINGLEUNWIND | PS_SINGLEEXIT); TAILQ_FOREACH(q, &pr->ps_threads, p_thr_link) { if (q == p || (q->p_flag & P_SUSPSINGLE) == 0) continue; atomic_clearbits_int(&q->p_flag, P_SUSPSINGLE); /* * if the thread was only stopped for single threading * then clearing that either makes it runnable or puts * it back into some sleep queue */ if (q->p_stat == SSTOP && (q->p_flag & flag) == 0) { if (q->p_wchan == NULL) setrunnable(q); else { atomic_clearbits_int(&q->p_flag, P_WSLEEP); q->p_stat = SSLEEP; } } } SCHED_UNLOCK(s); } void sigio_del(struct sigiolst *rmlist) { struct sigio *sigio; while ((sigio = LIST_FIRST(rmlist)) != NULL) { LIST_REMOVE(sigio, sio_pgsigio); crfree(sigio->sio_ucred); free(sigio, M_SIGIO, sizeof(*sigio)); } } void sigio_unlink(struct sigio_ref *sir, struct sigiolst *rmlist) { struct sigio *sigio; MUTEX_ASSERT_LOCKED(&sigio_lock); sigio = sir->sir_sigio; if (sigio != NULL) { KASSERT(sigio->sio_myref == sir); sir->sir_sigio = NULL; if (sigio->sio_pgid > 0) sigio->sio_proc = NULL; else sigio->sio_pgrp = NULL; LIST_REMOVE(sigio, sio_pgsigio); LIST_INSERT_HEAD(rmlist, sigio, sio_pgsigio); } } void sigio_free(struct sigio_ref *sir) { struct sigiolst rmlist; if (sir->sir_sigio == NULL) return; LIST_INIT(&rmlist); mtx_enter(&sigio_lock); sigio_unlink(sir, &rmlist); mtx_leave(&sigio_lock); sigio_del(&rmlist); } void sigio_freelist(struct sigiolst *sigiolst) { struct sigiolst rmlist; struct sigio *sigio; if (LIST_EMPTY(sigiolst)) return; LIST_INIT(&rmlist); mtx_enter(&sigio_lock); while ((sigio = LIST_FIRST(sigiolst)) != NULL) sigio_unlink(sigio->sio_myref, &rmlist); mtx_leave(&sigio_lock); sigio_del(&rmlist); } int sigio_setown(struct sigio_ref *sir, u_long cmd, caddr_t data) { struct sigiolst rmlist; struct proc *p = curproc; struct pgrp *pgrp = NULL; struct process *pr = NULL; struct sigio *sigio; int error; pid_t pgid = *(int *)data; if (pgid == 0) { sigio_free(sir); return (0); } if (cmd == TIOCSPGRP) { if (pgid < 0) return (EINVAL); pgid = -pgid; } sigio = malloc(sizeof(*sigio), M_SIGIO, M_WAITOK); sigio->sio_pgid = pgid; sigio->sio_ucred = crhold(p->p_ucred); sigio->sio_myref = sir; LIST_INIT(&rmlist); /* * The kernel lock, and not sleeping between prfind()/pgfind() and * linking of the sigio ensure that the process or process group does * not disappear unexpectedly. */ KERNEL_LOCK(); mtx_enter(&sigio_lock); if (pgid > 0) { pr = prfind(pgid); if (pr == NULL) { error = ESRCH; goto fail; } /* * Policy - Don't allow a process to FSETOWN a process * in another session. * * Remove this test to allow maximum flexibility or * restrict FSETOWN to the current process or process * group for maximum safety. */ if (pr->ps_session != p->p_p->ps_session) { error = EPERM; goto fail; } if ((pr->ps_flags & PS_EXITING) != 0) { error = ESRCH; goto fail; } } else /* if (pgid < 0) */ { pgrp = pgfind(-pgid); if (pgrp == NULL) { error = ESRCH; goto fail; } /* * Policy - Don't allow a process to FSETOWN a process * in another session. * * Remove this test to allow maximum flexibility or * restrict FSETOWN to the current process or process * group for maximum safety. */ if (pgrp->pg_session != p->p_p->ps_session) { error = EPERM; goto fail; } } if (pgid > 0) { sigio->sio_proc = pr; LIST_INSERT_HEAD(&pr->ps_sigiolst, sigio, sio_pgsigio); } else { sigio->sio_pgrp = pgrp; LIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio); } sigio_unlink(sir, &rmlist); sir->sir_sigio = sigio; mtx_leave(&sigio_lock); KERNEL_UNLOCK(); sigio_del(&rmlist); return (0); fail: mtx_leave(&sigio_lock); KERNEL_UNLOCK(); crfree(sigio->sio_ucred); free(sigio, M_SIGIO, sizeof(*sigio)); return (error); } void sigio_getown(struct sigio_ref *sir, u_long cmd, caddr_t data) { struct sigio *sigio; pid_t pgid = 0; mtx_enter(&sigio_lock); sigio = sir->sir_sigio; if (sigio != NULL) pgid = sigio->sio_pgid; mtx_leave(&sigio_lock); if (cmd == TIOCGPGRP) pgid = -pgid; *(int *)data = pgid; } void sigio_copy(struct sigio_ref *dst, struct sigio_ref *src) { struct sigiolst rmlist; struct sigio *newsigio, *sigio; sigio_free(dst); if (src->sir_sigio == NULL) return; newsigio = malloc(sizeof(*newsigio), M_SIGIO, M_WAITOK); LIST_INIT(&rmlist); mtx_enter(&sigio_lock); sigio = src->sir_sigio; if (sigio == NULL) { mtx_leave(&sigio_lock); free(newsigio, M_SIGIO, sizeof(*newsigio)); return; } newsigio->sio_pgid = sigio->sio_pgid; newsigio->sio_ucred = crhold(sigio->sio_ucred); newsigio->sio_myref = dst; if (newsigio->sio_pgid > 0) { newsigio->sio_proc = sigio->sio_proc; LIST_INSERT_HEAD(&newsigio->sio_proc->ps_sigiolst, newsigio, sio_pgsigio); } else { newsigio->sio_pgrp = sigio->sio_pgrp; LIST_INSERT_HEAD(&newsigio->sio_pgrp->pg_sigiolst, newsigio, sio_pgsigio); } sigio_unlink(dst, &rmlist); dst->sir_sigio = newsigio; mtx_leave(&sigio_lock); sigio_del(&rmlist); }