/* * Copyright (c) 1995-2016 Apple Inc. All rights reserved. * * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. The rights granted to you under the License * may not be used to create, or enable the creation or redistribution of, * unlawful or unlicensed copies of an Apple operating system, or to * circumvent, violate, or enable the circumvention or violation of, any * terms of an Apple operating system software license agreement. * * Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ /* * Copyright (c) 1982, 1986, 1989, 1991, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94 */ /* * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce * support for mandatory and extensible security protections. This notice * is included in support of clause 2.2 (b) of the Apple Public License, * Version 2.0. */ #define SIGPROP /* include signal properties table */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* for coredump */ #include /* for APC support */ #include #include /* extern void *get_bsdtask_info(task_t); */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #if CONFIG_MACF #include #endif /* * Missing prototypes that Mach should export * * +++ */ extern int thread_enable_fpe(thread_t act, int onoff); extern kern_return_t get_signalact(task_t, thread_t *, int); extern unsigned int get_useraddr(void); extern boolean_t task_did_exec(task_t task); extern boolean_t task_is_exec_copy(task_t task); extern void vm_shared_region_reslide_stale(boolean_t driverkit); /* * --- */ extern void doexception(int exc, mach_exception_code_t code, mach_exception_subcode_t sub); static void stop(proc_t, proc_t); static int cansignal_nomac(proc_t, kauth_cred_t, proc_t, int); int cansignal(proc_t, kauth_cred_t, proc_t, int); int killpg1(proc_t, int, int, int, int); kern_return_t do_bsdexception(int, int, int); void __posix_sem_syscall_return(kern_return_t); char *proc_name_address(void *p); static int filt_sigattach(struct knote *kn, struct kevent_qos_s *kev); static void filt_sigdetach(struct knote *kn); static int filt_signal(struct knote *kn, long hint); static int filt_signaltouch(struct knote *kn, struct kevent_qos_s *kev); static int filt_signalprocess(struct knote *kn, struct kevent_qos_s *kev); SECURITY_READ_ONLY_EARLY(struct filterops) sig_filtops = { .f_attach = filt_sigattach, .f_detach = filt_sigdetach, .f_event = filt_signal, .f_touch = filt_signaltouch, .f_process = filt_signalprocess, }; /* structures and fns for killpg1 iterartion callback and filters */ struct killpg1_filtargs { bool posix; proc_t curproc; }; struct killpg1_iterargs { proc_t curproc; kauth_cred_t uc; int signum; int nfound; }; static int killpg1_allfilt(proc_t p, void * arg); static int killpg1_callback(proc_t p, void * arg); static int pgsignal_callback(proc_t p, void * arg); static kern_return_t get_signalthread(proc_t, int, thread_t *); /* flags for psignal_internal */ #define PSIG_LOCKED 0x1 #define PSIG_VFORK 0x2 #define PSIG_THREAD 0x4 #define PSIG_TRY_THREAD 0x8 static os_reason_t build_signal_reason(int signum, const char *procname); static void psignal_internal(proc_t p, task_t task, thread_t thread, int flavor, int signum, os_reason_t signal_reason); /* * NOTE: Source and target may *NOT* overlap! (target is smaller) */ static void sigaltstack_kern_to_user32(struct kern_sigaltstack *in, struct user32_sigaltstack *out) { out->ss_sp = CAST_DOWN_EXPLICIT(user32_addr_t, in->ss_sp); out->ss_size = CAST_DOWN_EXPLICIT(user32_size_t, in->ss_size); out->ss_flags = in->ss_flags; } static void sigaltstack_kern_to_user64(struct kern_sigaltstack *in, struct user64_sigaltstack *out) { out->ss_sp = in->ss_sp; out->ss_size = in->ss_size; out->ss_flags = in->ss_flags; } /* * NOTE: Source and target may are permitted to overlap! (source is smaller); * this works because we copy fields in order from the end of the struct to * the beginning. */ static void sigaltstack_user32_to_kern(struct user32_sigaltstack *in, struct kern_sigaltstack *out) { out->ss_flags = in->ss_flags; out->ss_size = in->ss_size; out->ss_sp = CAST_USER_ADDR_T(in->ss_sp); } static void sigaltstack_user64_to_kern(struct user64_sigaltstack *in, struct kern_sigaltstack *out) { out->ss_flags = in->ss_flags; out->ss_size = (user_size_t)in->ss_size; out->ss_sp = (user_addr_t)in->ss_sp; } static void sigaction_kern_to_user32(struct kern_sigaction *in, struct user32_sigaction *out) { /* This assumes 32 bit __sa_handler is of type sig_t */ out->__sigaction_u.__sa_handler = CAST_DOWN_EXPLICIT(user32_addr_t, in->__sigaction_u.__sa_handler); out->sa_mask = in->sa_mask; out->sa_flags = in->sa_flags; } static void sigaction_kern_to_user64(struct kern_sigaction *in, struct user64_sigaction *out) { /* This assumes 32 bit __sa_handler is of type sig_t */ out->__sigaction_u.__sa_handler = in->__sigaction_u.__sa_handler; out->sa_mask = in->sa_mask; out->sa_flags = in->sa_flags; } static void __sigaction_user32_to_kern(struct __user32_sigaction *in, struct __kern_sigaction *out) { out->__sigaction_u.__sa_handler = CAST_USER_ADDR_T(in->__sigaction_u.__sa_handler); out->sa_tramp = CAST_USER_ADDR_T(in->sa_tramp); out->sa_mask = in->sa_mask; out->sa_flags = in->sa_flags; kern_return_t kr; kr = machine_thread_function_pointers_convert_from_user(current_thread(), &out->sa_tramp, 1); assert(kr == KERN_SUCCESS); } static void __sigaction_user64_to_kern(struct __user64_sigaction *in, struct __kern_sigaction *out) { out->__sigaction_u.__sa_handler = (user_addr_t)in->__sigaction_u.__sa_handler; out->sa_tramp = (user_addr_t)in->sa_tramp; out->sa_mask = in->sa_mask; out->sa_flags = in->sa_flags; kern_return_t kr; kr = machine_thread_function_pointers_convert_from_user(current_thread(), &out->sa_tramp, 1); assert(kr == KERN_SUCCESS); } #if SIGNAL_DEBUG void ram_printf(int); int ram_debug = 0; unsigned int rdebug_proc = 0; void ram_printf(int x) { printf("x is %d", x); } #endif /* SIGNAL_DEBUG */ void signal_setast(thread_t sig_actthread) { act_set_astbsd(sig_actthread); } static int cansignal_nomac(proc_t src, kauth_cred_t uc_src, proc_t dst, int signum) { /* you can signal yourself */ if (src == dst) { return 1; } /* you can't send the init proc SIGKILL, even if root */ if (signum == SIGKILL && dst == initproc) { return 0; } /* otherwise, root can always signal */ if (kauth_cred_issuser(uc_src)) { return 1; } /* processes in the same session can send SIGCONT to each other */ if (signum == SIGCONT && proc_sessionid(src) == proc_sessionid(dst)) { return 1; } #if XNU_TARGET_OS_IOS // Allow debugging of third party drivers on iOS if (proc_is_third_party_debuggable_driver(dst)) { return 1; } #endif /* XNU_TARGET_OS_IOS */ /* the source process must be authorized to signal the target */ { int allowed = 0; kauth_cred_t uc_dst = NOCRED, uc_ref = NOCRED; uc_dst = uc_ref = kauth_cred_proc_ref(dst); /* * If the real or effective UID of the sender matches the real or saved * UID of the target, allow the signal to be sent. */ if (kauth_cred_getruid(uc_src) == kauth_cred_getruid(uc_dst) || kauth_cred_getruid(uc_src) == kauth_cred_getsvuid(uc_dst) || kauth_cred_getuid(uc_src) == kauth_cred_getruid(uc_dst) || kauth_cred_getuid(uc_src) == kauth_cred_getsvuid(uc_dst)) { allowed = 1; } if (uc_ref != NOCRED) { kauth_cred_unref(&uc_ref); uc_ref = NOCRED; } return allowed; } } /* * Can process `src`, with ucred `uc_src`, send the signal `signum` to process * `dst`? The ucred is referenced by the caller so internal fileds can be used * safely. */ int cansignal(proc_t src, kauth_cred_t uc_src, proc_t dst, int signum) { #if CONFIG_MACF if (mac_proc_check_signal(src, dst, signum)) { return 0; } #endif return cansignal_nomac(src, uc_src, dst, signum); } /* * Some signals can be restricted from being handled, * forcing the default action for that signal. This behavior applies only to * non-root (EUID != 0) processes, and is configured with the "sigrestrict=x" * bootarg: * * 0 (default): Disallow use of restricted signals. Trying to register a handler * returns ENOTSUP, which userspace may use to take special action (e.g. abort). * 1: As above, but return EINVAL. Restricted signals behave similarly to SIGKILL. * 2: Usual POSIX semantics. */ static TUNABLE(unsigned, sigrestrict_arg, "sigrestrict", 0); #if XNU_PLATFORM_WatchOS static int sigrestrictmask(void) { if (kauth_getuid() != 0 && sigrestrict_arg != 2) { return SIGRESTRICTMASK; } return 0; } static int signal_is_restricted(proc_t p, int signum) { if (sigmask(signum) & sigrestrictmask()) { if (sigrestrict_arg == 0 && task_get_apptype(proc_task(p)) == TASK_APPTYPE_APP_DEFAULT) { return ENOTSUP; } else { return EINVAL; } } return 0; } #else static inline int signal_is_restricted(proc_t p, int signum) { (void)p; (void)signum; return 0; } #endif /* !XNU_PLATFORM_WatchOS */ /* * Returns: 0 Success * EINVAL * copyout:EFAULT * copyin:EFAULT * * Notes: Uses current thread as a parameter to inform PPC to enable * FPU exceptions via setsigvec(); this operation is not proxy * safe! */ /* ARGSUSED */ int sigaction(proc_t p, struct sigaction_args *uap, __unused int32_t *retval) { struct kern_sigaction vec; struct __kern_sigaction __vec; struct kern_sigaction *sa = &vec; struct sigacts *ps = &p->p_sigacts; int signum; int bit, error = 0; uint32_t sigreturn_validation = PS_SIGRETURN_VALIDATION_DEFAULT; signum = uap->signum; if (signum <= 0 || signum >= NSIG || signum == SIGKILL || signum == SIGSTOP) { return EINVAL; } if (uap->nsa) { if (IS_64BIT_PROCESS(p)) { struct __user64_sigaction __vec64; error = copyin(uap->nsa, &__vec64, sizeof(__vec64)); __sigaction_user64_to_kern(&__vec64, &__vec); } else { struct __user32_sigaction __vec32; error = copyin(uap->nsa, &__vec32, sizeof(__vec32)); __sigaction_user32_to_kern(&__vec32, &__vec); } if (error) { return error; } sigreturn_validation = (__vec.sa_flags & SA_VALIDATE_SIGRETURN_FROM_SIGTRAMP) ? PS_SIGRETURN_VALIDATION_ENABLED : PS_SIGRETURN_VALIDATION_DISABLED; __vec.sa_flags &= SA_USERSPACE_MASK; /* Only pass on valid sa_flags */ if ((__vec.sa_flags & SA_SIGINFO) || __vec.sa_handler != SIG_DFL) { if ((error = signal_is_restricted(p, signum))) { if (error == ENOTSUP) { printf("%s(%d): denied attempt to register action for signal %d\n", proc_name_address(p), proc_pid(p), signum); } return error; } } } if (uap->osa) { sa->sa_handler = SIGACTION(p, 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_siginfo & bit) { sa->sa_flags |= SA_SIGINFO; } if (ps->ps_signodefer & bit) { sa->sa_flags |= SA_NODEFER; } if ((signum == SIGCHLD) && (p->p_flag & P_NOCLDSTOP)) { sa->sa_flags |= SA_NOCLDSTOP; } if ((signum == SIGCHLD) && (p->p_flag & P_NOCLDWAIT)) { sa->sa_flags |= SA_NOCLDWAIT; } if (IS_64BIT_PROCESS(p)) { struct user64_sigaction vec64 = {}; sigaction_kern_to_user64(sa, &vec64); error = copyout(&vec64, uap->osa, sizeof(vec64)); } else { struct user32_sigaction vec32 = {}; sigaction_kern_to_user32(sa, &vec32); error = copyout(&vec32, uap->osa, sizeof(vec32)); } if (error) { return error; } } if (uap->nsa) { uint32_t old_sigreturn_validation = atomic_load_explicit( &ps->ps_sigreturn_validation, memory_order_relaxed); if (old_sigreturn_validation == PS_SIGRETURN_VALIDATION_DEFAULT) { atomic_compare_exchange_strong_explicit(&ps->ps_sigreturn_validation, &old_sigreturn_validation, sigreturn_validation, memory_order_relaxed, memory_order_relaxed); } error = setsigvec(p, current_thread(), signum, &__vec, FALSE); } return error; } /* Routines to manipulate bits on all threads */ int clear_procsiglist(proc_t p, int bit, boolean_t in_signalstart) { struct uthread * uth; proc_lock(p); if (!in_signalstart) { proc_signalstart(p, 1); } TAILQ_FOREACH(uth, &p->p_uthlist, uu_list) { uth->uu_siglist &= ~bit; } p->p_siglist &= ~bit; if (!in_signalstart) { proc_signalend(p, 1); } proc_unlock(p); return 0; } static int unblock_procsigmask(proc_t p, int bit) { struct uthread * uth; proc_lock(p); proc_signalstart(p, 1); TAILQ_FOREACH(uth, &p->p_uthlist, uu_list) { uth->uu_sigmask &= ~bit; } p->p_sigmask &= ~bit; proc_signalend(p, 1); proc_unlock(p); return 0; } static int block_procsigmask(proc_t p, int bit) { struct uthread * uth; proc_lock(p); proc_signalstart(p, 1); TAILQ_FOREACH(uth, &p->p_uthlist, uu_list) { uth->uu_sigmask |= bit; } p->p_sigmask |= bit; proc_signalend(p, 1); proc_unlock(p); return 0; } int set_procsigmask(proc_t p, int bit) { struct uthread * uth; proc_lock(p); proc_signalstart(p, 1); TAILQ_FOREACH(uth, &p->p_uthlist, uu_list) { uth->uu_sigmask = bit; } p->p_sigmask = bit; proc_signalend(p, 1); proc_unlock(p); return 0; } /* XXX should be static? */ /* * Notes: The thread parameter is used in the PPC case to select the * thread on which the floating point exception will be enabled * or disabled. We can't simply take current_thread(), since * this is called from posix_spawn() on the not currently running * process/thread pair. * * We mark thread as unused to alow compilation without warning * on non-PPC platforms. */ int setsigvec(proc_t p, __unused thread_t thread, int signum, struct __kern_sigaction *sa, boolean_t in_sigstart) { struct sigacts *ps = &p->p_sigacts; int bit; assert(signum < NSIG); if ((signum == SIGKILL || signum == SIGSTOP) && sa->sa_handler != SIG_DFL) { return EINVAL; } bit = sigmask(signum); /* * Change setting atomically. */ proc_set_sigact_trampact(p, signum, sa->sa_handler, sa->sa_tramp); ps->ps_catchmask[signum] = sa->sa_mask & ~sigcantmask; if (sa->sa_flags & SA_SIGINFO) { 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) { ps->ps_sigonstack |= bit; } else { ps->ps_sigonstack &= ~bit; } if (sa->sa_flags & SA_RESETHAND) { ps->ps_sigreset |= bit; } else { ps->ps_sigreset &= ~bit; } if (sa->sa_flags & SA_NODEFER) { ps->ps_signodefer |= bit; } else { ps->ps_signodefer &= ~bit; } if (signum == SIGCHLD) { if (sa->sa_flags & SA_NOCLDSTOP) { OSBitOrAtomic(P_NOCLDSTOP, &p->p_flag); } else { OSBitAndAtomic(~((uint32_t)P_NOCLDSTOP), &p->p_flag); } if ((sa->sa_flags & SA_NOCLDWAIT) || (sa->sa_handler == SIG_IGN)) { OSBitOrAtomic(P_NOCLDWAIT, &p->p_flag); } else { OSBitAndAtomic(~((uint32_t)P_NOCLDWAIT), &p->p_flag); } } /* * Set bit in p_sigignore for signals that are set to SIG_IGN, * and for signals set to SIG_DFL where the default is to ignore. * However, don't put SIGCONT in p_sigignore, * as we have to restart the process. */ if (sa->sa_handler == SIG_IGN || (sigprop[signum] & SA_IGNORE && sa->sa_handler == SIG_DFL)) { clear_procsiglist(p, bit, in_sigstart); if (signum != SIGCONT) { p->p_sigignore |= bit; /* easier in psignal */ } p->p_sigcatch &= ~bit; } else { p->p_sigignore &= ~bit; if (sa->sa_handler == SIG_DFL) { p->p_sigcatch &= ~bit; } else { p->p_sigcatch |= bit; } } return 0; } /* * Initialize signal state for process 0; * set to ignore signals that are ignored by default. */ void siginit(proc_t p) { int i; for (i = 1; i < NSIG; i++) { if (sigprop[i] & SA_IGNORE && i != SIGCONT) { p->p_sigignore |= sigmask(i); } } } /* * Reset signals for an exec of the specified process. */ void execsigs(proc_t p, thread_t thread) { struct sigacts *ps = &p->p_sigacts; int nc, mask; struct uthread *ut; ut = (struct uthread *)get_bsdthread_info(thread); /* * transfer saved signal states from the process * back to the current thread. * * NOTE: We do this without the process locked, * because we are guaranteed to be single-threaded * by this point in exec and the p_siglist is * only accessed by threads inside the process. */ ut->uu_siglist |= p->p_siglist; p->p_siglist = 0; /* * Reset caught signals. Held signals remain held * through p_sigmask (unless they were caught, * and are now ignored by default). */ proc_reset_sigact(p, p->p_sigcatch); while (p->p_sigcatch) { nc = ffs((unsigned int)p->p_sigcatch); mask = sigmask(nc); p->p_sigcatch &= ~mask; if (sigprop[nc] & SA_IGNORE) { if (nc != SIGCONT) { p->p_sigignore |= mask; } ut->uu_siglist &= ~mask; } } atomic_store_explicit(&ps->ps_sigreturn_validation, PS_SIGRETURN_VALIDATION_DEFAULT, memory_order_relaxed); /* * Reset stack state to the user stack. * Clear set of signals caught on the signal stack. */ /* thread */ ut->uu_sigstk.ss_flags = SA_DISABLE; ut->uu_sigstk.ss_size = 0; ut->uu_sigstk.ss_sp = USER_ADDR_NULL; ut->uu_flag &= ~UT_ALTSTACK; /* process */ ps->ps_sigonstack = 0; } /* * Manipulate signal mask. * Note that we receive new mask, not pointer, * and return old mask as return value; * the library stub does the rest. */ int sigprocmask(proc_t p, struct sigprocmask_args *uap, __unused int32_t *retval) { int error = 0; sigset_t oldmask, nmask; user_addr_t omask = uap->omask; struct uthread *ut; ut = current_uthread(); oldmask = ut->uu_sigmask; if (uap->mask == USER_ADDR_NULL) { /* just want old mask */ goto out; } error = copyin(uap->mask, &nmask, sizeof(sigset_t)); if (error) { goto out; } switch (uap->how) { case SIG_BLOCK: block_procsigmask(p, (nmask & ~sigcantmask)); signal_setast(current_thread()); break; case SIG_UNBLOCK: unblock_procsigmask(p, (nmask & ~sigcantmask)); signal_setast(current_thread()); break; case SIG_SETMASK: set_procsigmask(p, (nmask & ~sigcantmask)); signal_setast(current_thread()); break; default: error = EINVAL; break; } out: if (!error && omask != USER_ADDR_NULL) { copyout(&oldmask, omask, sizeof(sigset_t)); } return error; } int sigpending(__unused proc_t p, struct sigpending_args *uap, __unused int32_t *retval) { struct uthread *ut; sigset_t pendlist; ut = current_uthread(); pendlist = ut->uu_siglist; if (uap->osv) { copyout(&pendlist, uap->osv, sizeof(sigset_t)); } return 0; } /* * Suspend process until signal, providing mask to be set * in the meantime. Note nonstandard calling convention: * libc stub passes mask, not pointer, to save a copyin. */ static int sigcontinue(__unused int error) { // struct uthread *ut = current_uthread(); unix_syscall_return(EINTR); } int sigsuspend(proc_t p, struct sigsuspend_args *uap, int32_t *retval) { __pthread_testcancel(1); return sigsuspend_nocancel(p, (struct sigsuspend_nocancel_args *)uap, retval); } int sigsuspend_nocancel(proc_t p, struct sigsuspend_nocancel_args *uap, __unused int32_t *retval) { struct uthread *ut; ut = current_uthread(); /* * When returning from sigpause, we want * the old mask to be restored after the * signal handler has finished. Thus, we * save it here and mark the sigacts structure * to indicate this. */ ut->uu_oldmask = ut->uu_sigmask; ut->uu_flag |= UT_SAS_OLDMASK; ut->uu_sigmask = (uap->mask & ~sigcantmask); (void) tsleep0((caddr_t) p, PPAUSE | PCATCH, "pause", 0, sigcontinue); /* always return EINTR rather than ERESTART... */ return EINTR; } int __disable_threadsignal(__unused proc_t p, __unused struct __disable_threadsignal_args *uap, __unused int32_t *retval) { struct uthread *uth; uth = current_uthread(); /* No longer valid to have any signal delivered */ uth->uu_flag |= (UT_NO_SIGMASK | UT_CANCELDISABLE); return 0; } void __pthread_testcancel(int presyscall) { thread_t self = current_thread(); struct uthread * uthread; uthread = (struct uthread *)get_bsdthread_info(self); uthread->uu_flag &= ~UT_NOTCANCELPT; if ((uthread->uu_flag & (UT_CANCELDISABLE | UT_CANCEL | UT_CANCELED)) == UT_CANCEL) { if (presyscall != 0) { unix_syscall_return(EINTR); /* NOTREACHED */ } else { thread_abort_safely(self); } } } int __pthread_markcancel(__unused proc_t p, struct __pthread_markcancel_args *uap, __unused int32_t *retval) { thread_act_t target_act; int error = 0; struct uthread *uth; target_act = (thread_act_t)port_name_to_thread(uap->thread_port, PORT_INTRANS_THREAD_IN_CURRENT_TASK); if (target_act == THR_ACT_NULL) { return ESRCH; } uth = (struct uthread *)get_bsdthread_info(target_act); if ((uth->uu_flag & (UT_CANCEL | UT_CANCELED)) == 0) { uth->uu_flag |= (UT_CANCEL | UT_NO_SIGMASK); if (((uth->uu_flag & UT_NOTCANCELPT) == 0) && ((uth->uu_flag & UT_CANCELDISABLE) == 0)) { thread_abort_safely(target_act); } } thread_deallocate(target_act); return error; } /* if action =0 ; return the cancellation state , * if marked for cancellation, make the thread canceled * if action = 1 ; Enable the cancel handling * if action = 2; Disable the cancel handling */ int __pthread_canceled(__unused proc_t p, struct __pthread_canceled_args *uap, __unused int32_t *retval) { thread_act_t thread; struct uthread *uth; int action = uap->action; thread = current_thread(); uth = (struct uthread *)get_bsdthread_info(thread); switch (action) { case 1: uth->uu_flag &= ~UT_CANCELDISABLE; return 0; case 2: uth->uu_flag |= UT_CANCELDISABLE; return 0; case 0: default: if ((uth->uu_flag & (UT_CANCELDISABLE | UT_CANCEL | UT_CANCELED)) == UT_CANCEL) { uth->uu_flag &= ~UT_CANCEL; uth->uu_flag |= (UT_CANCELED | UT_NO_SIGMASK); return 0; } return EINVAL; } return EINVAL; } __attribute__((noreturn)) void __posix_sem_syscall_return(kern_return_t kern_result) { int error = 0; if (kern_result == KERN_SUCCESS) { error = 0; } else if (kern_result == KERN_ABORTED) { error = EINTR; } else if (kern_result == KERN_OPERATION_TIMED_OUT) { error = ETIMEDOUT; } else { error = EINVAL; } unix_syscall_return(error); /* does not return */ } /* * Returns: 0 Success * EINTR * ETIMEDOUT * EINVAL * EFAULT if timespec is NULL */ int __semwait_signal(proc_t p, struct __semwait_signal_args *uap, int32_t *retval) { __pthread_testcancel(0); return __semwait_signal_nocancel(p, (struct __semwait_signal_nocancel_args *)uap, retval); } int __semwait_signal_nocancel(__unused proc_t p, struct __semwait_signal_nocancel_args *uap, __unused int32_t *retval) { kern_return_t kern_result; mach_timespec_t then; struct timespec now; struct user_timespec ts; boolean_t truncated_timeout = FALSE; if (uap->timeout) { ts.tv_sec = (user_time_t)uap->tv_sec; ts.tv_nsec = uap->tv_nsec; if ((ts.tv_sec & 0xFFFFFFFF00000000ULL) != 0) { ts.tv_sec = 0xFFFFFFFF; ts.tv_nsec = 0; truncated_timeout = TRUE; } if (uap->relative) { then.tv_sec = (unsigned int)ts.tv_sec; then.tv_nsec = (clock_res_t)ts.tv_nsec; } else { nanotime(&now); /* if time has elapsed, set time to null timepsec to bailout rightaway */ if (now.tv_sec == ts.tv_sec ? now.tv_nsec > ts.tv_nsec : now.tv_sec > ts.tv_sec) { then.tv_sec = 0; then.tv_nsec = 0; } else { then.tv_sec = (unsigned int)(ts.tv_sec - now.tv_sec); then.tv_nsec = (clock_res_t)(ts.tv_nsec - now.tv_nsec); if (then.tv_nsec < 0) { then.tv_nsec += NSEC_PER_SEC; then.tv_sec--; } } } if (uap->mutex_sem == 0) { kern_result = semaphore_timedwait_trap_internal((mach_port_name_t)uap->cond_sem, then.tv_sec, then.tv_nsec, __posix_sem_syscall_return); } else { kern_result = semaphore_timedwait_signal_trap_internal(uap->cond_sem, uap->mutex_sem, then.tv_sec, then.tv_nsec, __posix_sem_syscall_return); } } else { if (uap->mutex_sem == 0) { kern_result = semaphore_wait_trap_internal(uap->cond_sem, __posix_sem_syscall_return); } else { kern_result = semaphore_wait_signal_trap_internal(uap->cond_sem, uap->mutex_sem, __posix_sem_syscall_return); } } if (kern_result == KERN_SUCCESS && !truncated_timeout) { return 0; } else if (kern_result == KERN_SUCCESS && truncated_timeout) { return EINTR; /* simulate an exceptional condition because Mach doesn't support a longer timeout */ } else if (kern_result == KERN_ABORTED) { return EINTR; } else if (kern_result == KERN_OPERATION_TIMED_OUT) { return ETIMEDOUT; } else { return EINVAL; } } int __pthread_kill(__unused proc_t p, struct __pthread_kill_args *uap, __unused int32_t *retval) { thread_t target_act; int error = 0; int signum = uap->sig; struct uthread *uth; target_act = (thread_t)port_name_to_thread(uap->thread_port, PORT_INTRANS_OPTIONS_NONE); if (target_act == THREAD_NULL) { return ESRCH; } if ((u_int)signum >= NSIG) { error = EINVAL; goto out; } uth = (struct uthread *)get_bsdthread_info(target_act); if (uth->uu_flag & UT_NO_SIGMASK) { error = ESRCH; goto out; } /* * workq threads must have kills enabled through either * BSDTHREAD_CTL_WORKQ_ALLOW_KILL or BSDTHREAD_CTL_WORKQ_ALLOW_SIGMASK */ if ((thread_get_tag(target_act) & THREAD_TAG_WORKQUEUE) && !(uth->uu_workq_pthread_kill_allowed || p->p_workq_allow_sigmask)) { error = ENOTSUP; goto out; } if (signum) { psignal_uthread(target_act, signum); } out: thread_deallocate(target_act); return error; } int __pthread_sigmask(__unused proc_t p, struct __pthread_sigmask_args *uap, __unused int32_t *retval) { user_addr_t set = uap->set; user_addr_t oset = uap->oset; sigset_t nset; int error = 0; struct uthread *ut; sigset_t oldset; ut = current_uthread(); oldset = ut->uu_sigmask; if (set == USER_ADDR_NULL) { /* need only old mask */ goto out; } error = copyin(set, &nset, sizeof(sigset_t)); if (error) { goto out; } switch (uap->how) { case SIG_BLOCK: ut->uu_sigmask |= (nset & ~sigcantmask); break; case SIG_UNBLOCK: ut->uu_sigmask &= ~(nset); signal_setast(current_thread()); break; case SIG_SETMASK: ut->uu_sigmask = (nset & ~sigcantmask); signal_setast(current_thread()); break; default: error = EINVAL; } out: if (!error && oset != USER_ADDR_NULL) { copyout(&oldset, oset, sizeof(sigset_t)); } return error; } /* * Returns: 0 Success * EINVAL * copyin:EFAULT * copyout:EFAULT */ int __sigwait(proc_t p, struct __sigwait_args *uap, int32_t *retval) { __pthread_testcancel(1); return __sigwait_nocancel(p, (struct __sigwait_nocancel_args *)uap, retval); } int __sigwait_nocancel(proc_t p, struct __sigwait_nocancel_args *uap, __unused int32_t *retval) { struct uthread *ut; struct uthread *uth; int error = 0; sigset_t mask; sigset_t siglist; sigset_t sigw = 0; int signum; ut = current_uthread(); if (uap->set == USER_ADDR_NULL) { return EINVAL; } error = copyin(uap->set, &mask, sizeof(sigset_t)); if (error) { return error; } siglist = (mask & ~sigcantmask); if (siglist == 0) { return EINVAL; } proc_lock(p); proc_signalstart(p, 1); TAILQ_FOREACH(uth, &p->p_uthlist, uu_list) { if ((sigw = uth->uu_siglist & siglist)) { break; } } proc_signalend(p, 1); if (sigw) { /* The signal was pending on a thread */ goto sigwait1; } /* * When returning from sigwait, 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. */ uth = ut; /* wait for it to be delivered to us */ ut->uu_oldmask = ut->uu_sigmask; ut->uu_flag |= UT_SAS_OLDMASK; if (siglist == (sigset_t)0) { proc_unlock(p); return EINVAL; } /* SIGKILL and SIGSTOP are not maskable as well */ ut->uu_sigmask = ~(siglist | sigcantmask); ut->uu_sigwait = siglist; /* No Continuations for now */ error = msleep((caddr_t)&ut->uu_sigwait, &p->p_mlock, PPAUSE | PCATCH, "pause", 0); if (error == ERESTART) { error = 0; } sigw = (ut->uu_sigwait & siglist); ut->uu_sigmask = ut->uu_oldmask; ut->uu_oldmask = 0; ut->uu_flag &= ~UT_SAS_OLDMASK; sigwait1: ut->uu_sigwait = 0; if (!error) { signum = ffs((unsigned int)sigw); if (!signum) { panic("sigwait with no signal wakeup"); } /* Clear the pending signal in the thread it was delivered */ uth->uu_siglist &= ~(sigmask(signum)); #if CONFIG_DTRACE DTRACE_PROC2(signal__clear, int, signum, siginfo_t *, &(ut->t_dtrace_siginfo)); #endif proc_unlock(p); if (uap->sig != USER_ADDR_NULL) { error = copyout(&signum, uap->sig, sizeof(int)); } } else { proc_unlock(p); } return error; } int sigaltstack(__unused proc_t p, struct sigaltstack_args *uap, __unused int32_t *retval) { struct kern_sigaltstack ss; struct kern_sigaltstack *pstk; int error; struct uthread *uth; int onstack; uth = current_uthread(); pstk = &uth->uu_sigstk; if ((uth->uu_flag & UT_ALTSTACK) == 0) { uth->uu_sigstk.ss_flags |= SA_DISABLE; } onstack = pstk->ss_flags & SA_ONSTACK; if (uap->oss) { if (IS_64BIT_PROCESS(p)) { struct user64_sigaltstack ss64 = {}; sigaltstack_kern_to_user64(pstk, &ss64); error = copyout(&ss64, uap->oss, sizeof(ss64)); } else { struct user32_sigaltstack ss32 = {}; sigaltstack_kern_to_user32(pstk, &ss32); error = copyout(&ss32, uap->oss, sizeof(ss32)); } if (error) { return error; } } if (uap->nss == USER_ADDR_NULL) { return 0; } if (IS_64BIT_PROCESS(p)) { struct user64_sigaltstack ss64; error = copyin(uap->nss, &ss64, sizeof(ss64)); sigaltstack_user64_to_kern(&ss64, &ss); } else { struct user32_sigaltstack ss32; error = copyin(uap->nss, &ss32, sizeof(ss32)); sigaltstack_user32_to_kern(&ss32, &ss); } if (error) { return error; } if ((ss.ss_flags & ~SA_DISABLE) != 0) { return EINVAL; } if (ss.ss_flags & SA_DISABLE) { /* if we are here we are not in the signal handler ;so no need to check */ if (uth->uu_sigstk.ss_flags & SA_ONSTACK) { return EINVAL; } uth->uu_flag &= ~UT_ALTSTACK; uth->uu_sigstk.ss_flags = ss.ss_flags; return 0; } if (onstack) { return EPERM; } /* The older stacksize was 8K, enforce that one so no compat problems */ #define OLDMINSIGSTKSZ 8*1024 if (ss.ss_size < OLDMINSIGSTKSZ) { return ENOMEM; } uth->uu_flag |= UT_ALTSTACK; uth->uu_sigstk = ss; return 0; } int kill(proc_t cp, struct kill_args *uap, __unused int32_t *retval) { proc_t p; kauth_cred_t uc = kauth_cred_get(); int posix = uap->posix; /* !0 if posix behaviour desired */ AUDIT_ARG(pid, uap->pid); AUDIT_ARG(signum, uap->signum); if ((u_int)uap->signum >= NSIG) { return EINVAL; } if (uap->pid > 0) { /* kill single process */ if ((p = proc_find(uap->pid)) == NULL) { if ((p = pzfind(uap->pid)) != NULL) { /* * POSIX 1003.1-2001 requires returning success when killing a * zombie; see Rationale for kill(2). */ return 0; } return ESRCH; } AUDIT_ARG(process, p); if (!cansignal(cp, uc, p, uap->signum)) { proc_rele(p); return EPERM; } if (uap->signum) { psignal(p, uap->signum); } proc_rele(p); return 0; } switch (uap->pid) { case -1: /* broadcast signal */ return killpg1(cp, uap->signum, 0, 1, posix); case 0: /* signal own process group */ return killpg1(cp, uap->signum, 0, 0, posix); default: /* negative explicit process group */ return killpg1(cp, uap->signum, -(uap->pid), 0, posix); } /* NOTREACHED */ } os_reason_t build_userspace_exit_reason(uint32_t reason_namespace, uint64_t reason_code, user_addr_t payload, uint32_t payload_size, user_addr_t reason_string, uint64_t reason_flags) { os_reason_t exit_reason = OS_REASON_NULL; int error = 0; int num_items_to_copy = 0; uint32_t user_data_to_copy = 0; char *reason_user_desc = NULL; size_t reason_user_desc_len = 0; exit_reason = os_reason_create(reason_namespace, reason_code); if (exit_reason == OS_REASON_NULL) { os_log(OS_LOG_DEFAULT, "build_userspace_exit_reason: failed to allocate exit reason\n"); return exit_reason; } exit_reason->osr_flags |= OS_REASON_FLAG_FROM_USERSPACE; /* * Only apply flags that are allowed to be passed from userspace. */ reason_flags = reason_flags & OS_REASON_FLAG_MASK_ALLOWED_FROM_USER; exit_reason->osr_flags |= reason_flags; if (!(exit_reason->osr_flags & OS_REASON_FLAG_NO_CRASH_REPORT)) { exit_reason->osr_flags |= OS_REASON_FLAG_GENERATE_CRASH_REPORT; } if (payload != USER_ADDR_NULL) { if (payload_size == 0) { os_log(OS_LOG_DEFAULT, "build_userspace_exit_reason: exit reason with namespace %u," " nonzero payload but zero length\n", reason_namespace); exit_reason->osr_flags |= OS_REASON_FLAG_BAD_PARAMS; payload = USER_ADDR_NULL; } else { num_items_to_copy++; if (payload_size > EXIT_REASON_PAYLOAD_MAX_LEN) { exit_reason->osr_flags |= OS_REASON_FLAG_PAYLOAD_TRUNCATED; payload_size = EXIT_REASON_PAYLOAD_MAX_LEN; } user_data_to_copy += payload_size; } } if (reason_string != USER_ADDR_NULL) { reason_user_desc = (char *)kalloc_data(EXIT_REASON_USER_DESC_MAX_LEN, Z_WAITOK); if (reason_user_desc != NULL) { error = copyinstr(reason_string, (void *) reason_user_desc, EXIT_REASON_USER_DESC_MAX_LEN, &reason_user_desc_len); if (error == 0) { num_items_to_copy++; user_data_to_copy += reason_user_desc_len; } else if (error == ENAMETOOLONG) { num_items_to_copy++; reason_user_desc[EXIT_REASON_USER_DESC_MAX_LEN - 1] = '\0'; user_data_to_copy += reason_user_desc_len; } else { exit_reason->osr_flags |= OS_REASON_FLAG_FAILED_DATA_COPYIN; kfree_data(reason_user_desc, EXIT_REASON_USER_DESC_MAX_LEN); reason_user_desc = NULL; reason_user_desc_len = 0; } } } if (num_items_to_copy != 0) { uint32_t reason_buffer_size_estimate = 0; mach_vm_address_t data_addr = 0; reason_buffer_size_estimate = kcdata_estimate_required_buffer_size(num_items_to_copy, user_data_to_copy); error = os_reason_alloc_buffer(exit_reason, reason_buffer_size_estimate); if (error != 0) { os_log(OS_LOG_DEFAULT, "build_userspace_exit_reason: failed to allocate signal reason buffer\n"); goto out_failed_copyin; } if (reason_user_desc != NULL && reason_user_desc_len != 0) { if (KERN_SUCCESS == kcdata_get_memory_addr(&exit_reason->osr_kcd_descriptor, EXIT_REASON_USER_DESC, (uint32_t)reason_user_desc_len, &data_addr)) { kcdata_memcpy(&exit_reason->osr_kcd_descriptor, (mach_vm_address_t) data_addr, reason_user_desc, (uint32_t)reason_user_desc_len); } else { os_log(OS_LOG_DEFAULT, "build_userspace_exit_reason: failed to allocate space for reason string\n"); goto out_failed_copyin; } } if (payload != USER_ADDR_NULL) { if (KERN_SUCCESS == kcdata_get_memory_addr(&exit_reason->osr_kcd_descriptor, EXIT_REASON_USER_PAYLOAD, payload_size, &data_addr)) { error = copyin(payload, (void *) data_addr, payload_size); if (error) { os_log(OS_LOG_DEFAULT, "build_userspace_exit_reason: failed to copy in payload data with error %d\n", error); goto out_failed_copyin; } } else { os_log(OS_LOG_DEFAULT, "build_userspace_exit_reason: failed to allocate space for payload data\n"); goto out_failed_copyin; } } } if (reason_user_desc != NULL) { kfree_data(reason_user_desc, EXIT_REASON_USER_DESC_MAX_LEN); reason_user_desc = NULL; reason_user_desc_len = 0; } return exit_reason; out_failed_copyin: if (reason_user_desc != NULL) { kfree_data(reason_user_desc, EXIT_REASON_USER_DESC_MAX_LEN); reason_user_desc = NULL; reason_user_desc_len = 0; } exit_reason->osr_flags |= OS_REASON_FLAG_FAILED_DATA_COPYIN; os_reason_alloc_buffer(exit_reason, 0); return exit_reason; } static int terminate_with_payload_internal(struct proc *cur_proc, int target_pid, uint32_t reason_namespace, uint64_t reason_code, user_addr_t payload, uint32_t payload_size, user_addr_t reason_string, uint64_t reason_flags) { proc_t target_proc = PROC_NULL; kauth_cred_t cur_cred = kauth_cred_get(); os_reason_t signal_reason = OS_REASON_NULL; AUDIT_ARG(pid, target_pid); if ((target_pid <= 0)) { return EINVAL; } target_proc = proc_find(target_pid); if (target_proc == PROC_NULL) { return ESRCH; } AUDIT_ARG(process, target_proc); if (!cansignal(cur_proc, cur_cred, target_proc, SIGKILL)) { proc_rele(target_proc); return EPERM; } if (target_pid != proc_getpid(cur_proc)) { /* * FLAG_ABORT should only be set on terminate_with_reason(getpid()) that * was a fallback from an unsuccessful abort_with_reason(). In that case * caller's pid matches the target one. Otherwise remove the flag. */ reason_flags &= ~((typeof(reason_flags))OS_REASON_FLAG_ABORT); } KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE, proc_getpid(target_proc), reason_namespace, reason_code, 0, 0); signal_reason = build_userspace_exit_reason(reason_namespace, reason_code, payload, payload_size, reason_string, (reason_flags | OS_REASON_FLAG_NO_CRASHED_TID)); if (target_pid == proc_getpid(cur_proc)) { /* * psignal_thread_with_reason() will pend a SIGKILL on the specified thread or * return if the thread and/or task are already terminating. Either way, the * current thread won't return to userspace. */ psignal_thread_with_reason(target_proc, current_thread(), SIGKILL, signal_reason); } else { psignal_with_reason(target_proc, SIGKILL, signal_reason); } proc_rele(target_proc); return 0; } int terminate_with_payload(struct proc *cur_proc, struct terminate_with_payload_args *args, __unused int32_t *retval) { return terminate_with_payload_internal(cur_proc, args->pid, args->reason_namespace, args->reason_code, args->payload, args->payload_size, args->reason_string, args->reason_flags); } static int killpg1_allfilt(proc_t p, void * arg) { struct killpg1_filtargs * kfargp = (struct killpg1_filtargs *)arg; /* * Don't signal initproc, a system process, or the current process if POSIX * isn't specified. */ return proc_getpid(p) > 1 && !(p->p_flag & P_SYSTEM) && (kfargp->posix ? true : p != kfargp->curproc); } static int killpg1_callback(proc_t p, void *arg) { struct killpg1_iterargs *kargp = (struct killpg1_iterargs *)arg; int signum = kargp->signum; if (proc_list_exited(p)) { /* * Count zombies as found for the purposes of signalling, since POSIX * 1003.1-2001 sees signalling zombies as successful. If killpg(2) or * kill(2) with pid -1 only finds zombies that can be signalled, it * shouldn't return ESRCH. See the Rationale for kill(2). * * Don't call into MAC -- it's not expecting signal checks for exited * processes. */ if (cansignal_nomac(kargp->curproc, kargp->uc, p, signum)) { kargp->nfound++; } } else if (cansignal(kargp->curproc, kargp->uc, p, signum)) { kargp->nfound++; if (signum != 0) { psignal(p, signum); } } return PROC_RETURNED; } /* * Common code for kill process group/broadcast kill. */ int killpg1(proc_t curproc, int signum, int pgid, int all, int posix) { kauth_cred_t uc; struct pgrp *pgrp; int error = 0; uc = kauth_cred_proc_ref(curproc); struct killpg1_iterargs karg = { .curproc = curproc, .uc = uc, .nfound = 0, .signum = signum }; if (all) { /* * Broadcast to all processes that the user can signal (pid was -1). */ struct killpg1_filtargs kfarg = { .posix = posix, .curproc = curproc }; proc_iterate(PROC_ALLPROCLIST | PROC_ZOMBPROCLIST, killpg1_callback, &karg, killpg1_allfilt, &kfarg); } else { if (pgid == 0) { /* * Send to current the current process' process group. */ pgrp = proc_pgrp(curproc, NULL); } else { pgrp = pgrp_find(pgid); if (pgrp == NULL) { error = ESRCH; goto out; } } pgrp_iterate(pgrp, killpg1_callback, &karg, ^bool (proc_t p) { if (p == kernproc || p == initproc) { return false; } /* XXX shouldn't this allow signalling zombies? */ return !(p->p_flag & P_SYSTEM) && p->p_stat != SZOMB; }); pgrp_rele(pgrp); } error = (karg.nfound > 0 ? 0 : (posix ? EPERM : ESRCH)); out: kauth_cred_unref(&uc); return error; } /* * Send a signal to a process group. */ void gsignal(int pgid, int signum) { struct pgrp *pgrp; if (pgid && (pgrp = pgrp_find(pgid))) { pgsignal(pgrp, signum, 0); pgrp_rele(pgrp); } } /* * Send a signal to a process group. If checkctty is 1, * limit to members which have a controlling terminal. */ static int pgsignal_callback(proc_t p, void * arg) { int signum = *(int*)arg; psignal(p, signum); return PROC_RETURNED; } void pgsignal(struct pgrp *pgrp, int signum, int checkctty) { if (pgrp == PGRP_NULL) { return; } bool (^filter)(proc_t) = ^bool (proc_t p) { return p->p_flag & P_CONTROLT; }; pgrp_iterate(pgrp, pgsignal_callback, &signum, checkctty ? filter : NULL); } void tty_pgsignal_locked(struct tty *tp, int signum, int checkctty) { struct pgrp * pg; pg = tty_pgrp_locked(tp); if (pg != PGRP_NULL) { tty_unlock(tp); pgsignal(pg, signum, checkctty); pgrp_rele(pg); tty_lock(tp); } } /* * Send a signal caused by a trap to a specific thread. */ void threadsignal(thread_t sig_actthread, int signum, mach_exception_code_t code, boolean_t set_exitreason) { struct uthread *uth; struct task * sig_task; proc_t p; int mask; if ((u_int)signum >= NSIG || signum == 0) { return; } mask = sigmask(signum); if ((mask & threadmask) == 0) { return; } sig_task = get_threadtask(sig_actthread); p = (proc_t)(get_bsdtask_info(sig_task)); uth = get_bsdthread_info(sig_actthread); proc_lock(p); if (!(p->p_lflag & P_LTRACED) && (p->p_sigignore & mask)) { proc_unlock(p); return; } uth->uu_siglist |= mask; uth->uu_code = code; /* Attempt to establish whether the signal will be fatal (mirrors logic in psignal_internal()) */ if (set_exitreason && ((p->p_lflag & P_LTRACED) || (!(uth->uu_sigwait & mask) && !(uth->uu_sigmask & mask) && !(p->p_sigcatch & mask))) && !(mask & stopsigmask) && !(mask & contsigmask)) { if (uth->uu_exit_reason == OS_REASON_NULL) { KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE, proc_getpid(p), OS_REASON_SIGNAL, signum, 0, 0); os_reason_t signal_reason = build_signal_reason(signum, "exc handler"); set_thread_exit_reason(sig_actthread, signal_reason, TRUE); /* We dropped/consumed the reference in set_thread_exit_reason() */ signal_reason = OS_REASON_NULL; } } proc_unlock(p); /* mark on process as well */ signal_setast(sig_actthread); } /* Called with proc locked */ static void set_thread_extra_flags(task_t task, struct uthread *uth, os_reason_t reason) { extern int vm_shared_region_reslide_restrict; boolean_t reslide_shared_region = FALSE; boolean_t driver = task_is_driver(task); assert(uth != NULL); /* * Check whether the userland fault address falls within the shared * region and notify userland if so. To limit the occurrences of shared * cache resliding - and its associated memory tax - only investigate the * fault if it is consequence of accessing unmapped memory (SIGSEGV) or * accessing with incorrect permissions (SIGBUS - KERN_PROTECTION_FAILURE). * * This allows launchd to apply special policies around this fault type. */ if (reason->osr_namespace == OS_REASON_SIGNAL && (reason->osr_code == SIGSEGV || (reason->osr_code == SIGBUS && uth->uu_code == KERN_PROTECTION_FAILURE))) { mach_vm_address_t fault_address = uth->uu_subcode; /* Address is in userland, so we hard clear any non-canonical bits to 0 here */ fault_address = VM_USER_STRIP_PTR(fault_address); if (fault_address >= SHARED_REGION_BASE && fault_address <= SHARED_REGION_BASE + SHARED_REGION_SIZE) { /* * Always report whether the fault happened within the shared cache * region, but only stale the slide if the resliding is extended * to all processes or if the process faulting is a platform one. */ reason->osr_flags |= OS_REASON_FLAG_SHAREDREGION_FAULT; #if __has_feature(ptrauth_calls) if (!vm_shared_region_reslide_restrict || task_is_hardened_binary(current_task())) { reslide_shared_region = TRUE; } #endif /* __has_feature(ptrauth_calls) */ } if (driver) { /* * Always reslide the DriverKit shared region if the driver faulted. * The memory cost is acceptable because the DriverKit shared cache is small * and there are relatively few driver processes. */ reslide_shared_region = TRUE; } } if (reslide_shared_region) { vm_shared_region_reslide_stale(driver); } } void set_thread_exit_reason(void *th, void *reason, boolean_t proc_locked) { struct uthread *targ_uth = get_bsdthread_info(th); struct task *targ_task = get_threadtask(th); proc_t targ_proc = NULL; os_reason_t exit_reason = (os_reason_t)reason; if (exit_reason == OS_REASON_NULL) { return; } if (!proc_locked) { targ_proc = (proc_t)(get_bsdtask_info(targ_task)); proc_lock(targ_proc); } set_thread_extra_flags(targ_task, targ_uth, exit_reason); if (targ_uth->uu_exit_reason == OS_REASON_NULL) { targ_uth->uu_exit_reason = exit_reason; } else { /* The caller expects that we drop a reference on the exit reason */ os_reason_free(exit_reason); } if (!proc_locked) { assert(targ_proc != NULL); proc_unlock(targ_proc); } } /* * get_signalthread * * Picks an appropriate thread from a process to target with a signal. * * Called with proc locked. * Returns thread with BSD ast set. * * We attempt to deliver a proc-wide signal to the first thread in the task. * This allows single threaded applications which use signals to * be able to be linked with multithreaded libraries. */ static kern_return_t get_signalthread(proc_t p, int signum, thread_t * thr) { struct uthread *uth; sigset_t mask = sigmask(signum); bool skip_wqthreads = true; *thr = THREAD_NULL; again: TAILQ_FOREACH(uth, &p->p_uthlist, uu_list) { if (((uth->uu_flag & UT_NO_SIGMASK) == 0) && (((uth->uu_sigmask & mask) == 0) || (uth->uu_sigwait & mask))) { thread_t th = get_machthread(uth); if (skip_wqthreads && (thread_get_tag(th) & THREAD_TAG_WORKQUEUE)) { /* Workqueue threads may be parked in the kernel unable to * deliver signals for an extended period of time, so skip them * in favor of pthreads in a first pass. (rdar://50054475). */ } else if (check_actforsig(proc_task(p), th, 1) == KERN_SUCCESS) { *thr = th; return KERN_SUCCESS; } } } if (skip_wqthreads) { skip_wqthreads = false; goto again; } if (get_signalact(proc_task(p), thr, 1) == KERN_SUCCESS) { return KERN_SUCCESS; } return KERN_FAILURE; } static os_reason_t build_signal_reason(int signum, const char *procname) { os_reason_t signal_reason = OS_REASON_NULL; proc_t sender_proc = current_proc(); uint32_t reason_buffer_size_estimate = 0, proc_name_length = 0; const char *default_sender_procname = "unknown"; mach_vm_address_t data_addr; int ret; signal_reason = os_reason_create(OS_REASON_SIGNAL, signum); if (signal_reason == OS_REASON_NULL) { printf("build_signal_reason: unable to allocate signal reason structure.\n"); return signal_reason; } reason_buffer_size_estimate = kcdata_estimate_required_buffer_size(2, sizeof(sender_proc->p_name) + sizeof(pid_t)); ret = os_reason_alloc_buffer_noblock(signal_reason, reason_buffer_size_estimate); if (ret != 0) { printf("build_signal_reason: unable to allocate signal reason buffer.\n"); return signal_reason; } if (KERN_SUCCESS == kcdata_get_memory_addr(&signal_reason->osr_kcd_descriptor, KCDATA_TYPE_PID, sizeof(pid_t), &data_addr)) { pid_t pid = proc_getpid(sender_proc); kcdata_memcpy(&signal_reason->osr_kcd_descriptor, data_addr, &pid, sizeof(pid)); } else { printf("build_signal_reason: exceeded space in signal reason buf, unable to log PID\n"); } proc_name_length = sizeof(sender_proc->p_name); if (KERN_SUCCESS == kcdata_get_memory_addr(&signal_reason->osr_kcd_descriptor, KCDATA_TYPE_PROCNAME, proc_name_length, &data_addr)) { if (procname) { char truncated_procname[proc_name_length]; strncpy((char *) &truncated_procname, procname, proc_name_length); truncated_procname[proc_name_length - 1] = '\0'; kcdata_memcpy(&signal_reason->osr_kcd_descriptor, data_addr, truncated_procname, (uint32_t)strlen((char *) &truncated_procname)); } else if (*sender_proc->p_name) { kcdata_memcpy(&signal_reason->osr_kcd_descriptor, data_addr, &sender_proc->p_name, sizeof(sender_proc->p_name)); } else { kcdata_memcpy(&signal_reason->osr_kcd_descriptor, data_addr, &default_sender_procname, (uint32_t)strlen(default_sender_procname) + 1); } } else { printf("build_signal_reason: exceeded space in signal reason buf, unable to log procname\n"); } return signal_reason; } /* * 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. * * Always drops a reference on a signal_reason if one is provided, whether via * passing it to a thread or deallocating directly. * * 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. */ static void psignal_internal(proc_t p, task_t task, thread_t thread, int flavor, int signum, os_reason_t signal_reason) { int prop; user_addr_t action = USER_ADDR_NULL; proc_t sig_proc; thread_t sig_thread; task_t sig_task; int mask; struct uthread *uth; kern_return_t kret; uid_t r_uid; proc_t pp; kauth_cred_t my_cred; char *launchd_exit_reason_desc = NULL; boolean_t update_thread_policy = FALSE; if ((u_int)signum >= NSIG || signum == 0) { panic("psignal: bad signal number %d", signum); } mask = sigmask(signum); prop = sigprop[signum]; #if SIGNAL_DEBUG if (rdebug_proc && (p != PROC_NULL) && (p == rdebug_proc)) { ram_printf(3); } #endif /* SIGNAL_DEBUG */ /* catch unexpected initproc kills early for easier debuggging */ if (signum == SIGKILL && p == initproc) { if (signal_reason == NULL) { panic_plain("unexpected SIGKILL of %s %s (no reason provided)", (p->p_name[0] != '\0' ? p->p_name : "initproc"), ((proc_getcsflags(p) & CS_KILLED) ? "(CS_KILLED)" : "")); } else { launchd_exit_reason_desc = exit_reason_get_string_desc(signal_reason); panic_plain("unexpected SIGKILL of %s %s with reason -- namespace %d code 0x%llx description %." LAUNCHD_PANIC_REASON_STRING_MAXLEN "s", (p->p_name[0] != '\0' ? p->p_name : "initproc"), ((proc_getcsflags(p) & CS_KILLED) ? "(CS_KILLED)" : ""), signal_reason->osr_namespace, signal_reason->osr_code, launchd_exit_reason_desc ? launchd_exit_reason_desc : "none"); } } /* * We will need the task pointer later. Grab it now to * check for a zombie process. Also don't send signals * to kernel internal tasks. */ if (flavor & PSIG_VFORK) { sig_task = task; sig_thread = thread; sig_proc = p; } else if (flavor & PSIG_THREAD) { sig_task = get_threadtask(thread); sig_thread = thread; sig_proc = (proc_t)get_bsdtask_info(sig_task); } else if (flavor & PSIG_TRY_THREAD) { assert((thread == current_thread()) && (p == current_proc())); sig_task = proc_task(p); sig_thread = thread; sig_proc = p; } else { sig_task = proc_task(p); sig_thread = THREAD_NULL; sig_proc = p; } if ((sig_task == TASK_NULL) || is_kerneltask(sig_task)) { os_reason_free(signal_reason); return; } if ((flavor & (PSIG_VFORK | PSIG_THREAD)) == 0) { proc_knote(sig_proc, NOTE_SIGNAL | signum); } if ((flavor & PSIG_LOCKED) == 0) { proc_signalstart(sig_proc, 0); } /* Don't send signals to a process that has ignored them. */ if (((flavor & PSIG_VFORK) == 0) && ((sig_proc->p_lflag & P_LTRACED) == 0) && (sig_proc->p_sigignore & mask)) { DTRACE_PROC3(signal__discard, thread_t, sig_thread, proc_t, sig_proc, int, signum); goto sigout_unlocked; } /* * The proc_lock prevents the targeted thread from being deallocated * or handling the signal until we're done signaling it. * * Once the proc_lock is dropped, we have no guarantee the thread or uthread exists anymore. * * XXX: What if the thread goes inactive after the thread passes bsd ast point? */ proc_lock(sig_proc); /* * Don't send signals to a process which has already exited and thus * committed to a particular p_xstat exit code. * Additionally, don't abort the process running 'reboot'. */ if (ISSET(sig_proc->p_flag, P_REBOOT) || ISSET(sig_proc->p_lflag, P_LEXIT)) { DTRACE_PROC3(signal__discard, thread_t, sig_thread, proc_t, sig_proc, int, signum); goto sigout_locked; } if (flavor & PSIG_VFORK) { action = SIG_DFL; act_set_astbsd(sig_thread); kret = KERN_SUCCESS; } else if (flavor & PSIG_TRY_THREAD) { uth = get_bsdthread_info(sig_thread); if (((uth->uu_flag & UT_NO_SIGMASK) == 0) && (((uth->uu_sigmask & mask) == 0) || (uth->uu_sigwait & mask)) && ((kret = check_actforsig(proc_task(sig_proc), sig_thread, 1)) == KERN_SUCCESS)) { /* deliver to specified thread */ } else { /* deliver to any willing thread */ kret = get_signalthread(sig_proc, signum, &sig_thread); } } else if (flavor & PSIG_THREAD) { /* If successful return with ast set */ kret = check_actforsig(sig_task, sig_thread, 1); } else { /* If successful return with ast set */ kret = get_signalthread(sig_proc, signum, &sig_thread); } if (kret != KERN_SUCCESS) { DTRACE_PROC3(signal__discard, thread_t, sig_thread, proc_t, sig_proc, int, signum); proc_unlock(sig_proc); goto sigout_unlocked; } uth = get_bsdthread_info(sig_thread); /* * If proc is traced, always give parent a chance. */ if ((flavor & PSIG_VFORK) == 0) { if (sig_proc->p_lflag & P_LTRACED) { action = SIG_DFL; } else { /* * If the signal is being ignored, * then we forget about it immediately. * (Note: we don't set SIGCONT in p_sigignore, * and if it is set to SIG_IGN, * action will be SIG_DFL here.) */ if (sig_proc->p_sigignore & mask) { goto sigout_locked; } if (uth->uu_sigwait & mask) { action = KERN_SIG_WAIT; } else if (uth->uu_sigmask & mask) { action = KERN_SIG_HOLD; } else if (sig_proc->p_sigcatch & mask) { action = KERN_SIG_CATCH; } else { action = SIG_DFL; } } } /* TODO: p_nice isn't hooked up to the scheduler... */ if (sig_proc->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && (sig_proc->p_lflag & P_LTRACED) == 0) { sig_proc->p_nice = NZERO; } if (prop & SA_CONT) { uth->uu_siglist &= ~stopsigmask; } if (prop & SA_STOP) { struct pgrp *pg; /* * 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. */ pg = proc_pgrp(sig_proc, NULL); if (prop & SA_TTYSTOP && pg->pg_jobc == 0 && action == SIG_DFL) { pgrp_rele(pg); goto sigout_locked; } pgrp_rele(pg); uth->uu_siglist &= ~contsigmask; } uth->uu_siglist |= mask; /* * Defer further processing for signals which are held, * except that stopped processes must be continued by SIGCONT. */ if ((action == KERN_SIG_HOLD) && ((prop & SA_CONT) == 0 || sig_proc->p_stat != SSTOP)) { goto sigout_locked; } /* * SIGKILL priority twiddling moved here from above because * it needs sig_thread. Could merge it into large switch * below if we didn't care about priority for tracing * as SIGKILL's action is always SIG_DFL. * * TODO: p_nice isn't hooked up to the scheduler... */ if ((signum == SIGKILL) && (sig_proc->p_nice > NZERO)) { sig_proc->p_nice = NZERO; } /* * Process is traced - wake it up (if not already * stopped) so that it can discover the signal in * issig() and stop for the parent. */ if (sig_proc->p_lflag & P_LTRACED) { if (sig_proc->p_stat != SSTOP) { goto runlocked; } else { goto sigout_locked; } } if ((flavor & PSIG_VFORK) != 0) { goto runlocked; } if (action == KERN_SIG_WAIT) { #if CONFIG_DTRACE /* * DTrace proc signal-clear returns a siginfo_t. Collect the needed info. */ r_uid = kauth_getruid(); /* per thread credential; protected by our thread context */ bzero((caddr_t)&(uth->t_dtrace_siginfo), sizeof(uth->t_dtrace_siginfo)); uth->t_dtrace_siginfo.si_signo = signum; uth->t_dtrace_siginfo.si_pid = proc_getpid(current_proc()); uth->t_dtrace_siginfo.si_status = W_EXITCODE(signum, 0); uth->t_dtrace_siginfo.si_uid = r_uid; uth->t_dtrace_siginfo.si_code = 0; #endif uth->uu_sigwait = mask; uth->uu_siglist &= ~mask; wakeup(&uth->uu_sigwait); /* if it is SIGCONT resume whole process */ if (prop & SA_CONT) { OSBitOrAtomic(P_CONTINUED, &sig_proc->p_flag); sig_proc->p_contproc = proc_getpid(current_proc()); (void) task_resume_internal(sig_task); } goto sigout_locked; } if (action != SIG_DFL) { /* * User wants to catch the signal. * Wake up the thread, but don't un-suspend it * (except for SIGCONT). */ if (prop & SA_CONT) { OSBitOrAtomic(P_CONTINUED, &sig_proc->p_flag); (void) task_resume_internal(sig_task); sig_proc->p_stat = SRUN; } else if (sig_proc->p_stat == SSTOP) { goto sigout_locked; } /* * Fill out siginfo structure information to pass to the * signalled process/thread sigaction handler, when it * wakes up. si_code is 0 because this is an ordinary * signal, not a SIGCHLD, and so si_status is the signal * number itself, instead of the child process exit status. * We shift this left because it will be shifted right before * it is passed to user space. kind of ugly to use W_EXITCODE * this way, but it beats defining a new macro. * * Note: Avoid the SIGCHLD recursion case! */ if (signum != SIGCHLD) { r_uid = kauth_getruid(); sig_proc->si_pid = proc_getpid(current_proc()); sig_proc->si_status = W_EXITCODE(signum, 0); sig_proc->si_uid = r_uid; sig_proc->si_code = 0; } goto runlocked; } else { /* Default action - varies */ if (mask & stopsigmask) { assert(signal_reason == NULL); /* * These are the signals which by default * stop a process. * * Don't clog system with children of init * stopped from the keyboard. */ if (!(prop & SA_STOP) && sig_proc->p_pptr == initproc) { uth->uu_siglist &= ~mask; proc_unlock(sig_proc); /* siglock still locked, proc_lock not locked */ psignal_locked(sig_proc, SIGKILL); goto sigout_unlocked; } /* * Stop the task * if task hasn't already been stopped by * a signal. */ uth->uu_siglist &= ~mask; if (sig_proc->p_stat != SSTOP) { sig_proc->p_xstat = signum; sig_proc->p_stat = SSTOP; OSBitAndAtomic(~((uint32_t)P_CONTINUED), &sig_proc->p_flag); sig_proc->p_lflag &= ~P_LWAITED; proc_signalend(sig_proc, 1); proc_unlock(sig_proc); pp = proc_parentholdref(sig_proc); proc_signalstart(sig_proc, 0); stop(sig_proc, pp); if ((pp != PROC_NULL) && ((pp->p_flag & P_NOCLDSTOP) == 0)) { my_cred = kauth_cred_proc_ref(sig_proc); r_uid = kauth_cred_getruid(my_cred); kauth_cred_unref(&my_cred); proc_lock(sig_proc); pp->si_pid = proc_getpid(sig_proc); /* * POSIX: sigaction for a stopped child * when sent to the parent must set the * child's signal number into si_status. */ if (signum != SIGSTOP) { pp->si_status = WEXITSTATUS(sig_proc->p_xstat); } else { pp->si_status = W_EXITCODE(signum, signum); } pp->si_code = CLD_STOPPED; pp->si_uid = r_uid; proc_unlock(sig_proc); psignal(pp, SIGCHLD); } if (pp != PROC_NULL) { proc_parentdropref(pp, 0); } goto sigout_unlocked; } goto sigout_locked; } DTRACE_PROC3(signal__send, thread_t, sig_thread, proc_t, p, int, signum); switch (signum) { /* * Signals ignored by default have been dealt * with already, since their bits are on in * p_sigignore. */ case SIGKILL: /* * Kill signal always sets process running and * unsuspends it. */ /* * Process will be running after 'run' */ sig_proc->p_stat = SRUN; /* * In scenarios where suspend/resume are racing * the signal we are missing AST_BSD by the time * we get here, set again to avoid races. This * was the scenario with spindump enabled shutdowns. * We would need to cover this approp down the line. */ act_set_astbsd(sig_thread); kret = thread_abort(sig_thread); update_thread_policy = (kret == KERN_SUCCESS); if (uth->uu_exit_reason == OS_REASON_NULL) { if (signal_reason == OS_REASON_NULL) { KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE, proc_getpid(sig_proc), OS_REASON_SIGNAL, signum, 0, 0); signal_reason = build_signal_reason(signum, NULL); } os_reason_ref(signal_reason); set_thread_exit_reason(sig_thread, signal_reason, TRUE); } goto sigout_locked; case SIGCONT: /* * Let the process run. If it's sleeping on an * event, it remains so. */ assert(signal_reason == NULL); OSBitOrAtomic(P_CONTINUED, &sig_proc->p_flag); sig_proc->p_contproc = proc_getpid(sig_proc); sig_proc->p_xstat = signum; (void) task_resume_internal(sig_task); /* * When processing a SIGCONT, we need to check * to see if there are signals pending that * were not delivered because we had been * previously stopped. If that's the case, * we need to thread_abort_safely() to trigger * interruption of the current system call to * cause their handlers to fire. If it's only * the SIGCONT, then don't wake up. */ if (((flavor & (PSIG_VFORK | PSIG_THREAD)) == 0) && (((uth->uu_siglist & ~uth->uu_sigmask) & ~sig_proc->p_sigignore) & ~mask)) { uth->uu_siglist &= ~mask; sig_proc->p_stat = SRUN; goto runlocked; } uth->uu_siglist &= ~mask; sig_proc->p_stat = SRUN; goto sigout_locked; default: { /* * A signal which has a default action of killing * the process, and for which there is no handler, * needs to act like SIGKILL * * The thread_sstop condition is a remnant of a fix * where PSIG_THREAD exit reasons were not set * correctly (93593933). We keep the behavior with * SSTOP the same as before. */ const bool default_kill = (action == SIG_DFL) && (prop & SA_KILL); const bool thread_sstop = (flavor & PSIG_THREAD) && (sig_proc->p_stat == SSTOP); if (default_kill && !thread_sstop) { sig_proc->p_stat = SRUN; kret = thread_abort(sig_thread); update_thread_policy = (kret == KERN_SUCCESS); if (uth->uu_exit_reason == OS_REASON_NULL) { if (signal_reason == OS_REASON_NULL) { KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE, proc_getpid(sig_proc), OS_REASON_SIGNAL, signum, 0, 0); signal_reason = build_signal_reason(signum, NULL); } os_reason_ref(signal_reason); set_thread_exit_reason(sig_thread, signal_reason, TRUE); } goto sigout_locked; } /* * All other signals wake up the process, but don't * resume it. */ if (sig_proc->p_stat == SSTOP) { goto sigout_locked; } goto runlocked; } } } /*NOTREACHED*/ runlocked: /* * If we're being traced (possibly because someone attached us * while we were stopped), check for a signal from the debugger. */ if (sig_proc->p_stat == SSTOP) { if ((sig_proc->p_lflag & P_LTRACED) != 0 && sig_proc->p_xstat != 0) { uth->uu_siglist |= sigmask(sig_proc->p_xstat); } if ((flavor & PSIG_VFORK) != 0) { sig_proc->p_stat = SRUN; } } else { /* * setrunnable(p) in BSD and * Wake up the thread if it is interruptible. */ sig_proc->p_stat = SRUN; if ((flavor & PSIG_VFORK) == 0) { thread_abort_safely(sig_thread); } } sigout_locked: if (update_thread_policy) { /* * Update the thread policy to heading to terminate, increase priority if * necessary. This needs to be done before we drop the proc lock because the * thread can take the fatal signal once it's dropped. */ proc_set_thread_policy(sig_thread, TASK_POLICY_ATTRIBUTE, TASK_POLICY_TERMINATED, TASK_POLICY_ENABLE); } proc_unlock(sig_proc); sigout_unlocked: os_reason_free(signal_reason); if ((flavor & PSIG_LOCKED) == 0) { proc_signalend(sig_proc, 0); } } void psignal(proc_t p, int signum) { psignal_internal(p, NULL, NULL, 0, signum, NULL); } void psignal_with_reason(proc_t p, int signum, struct os_reason *signal_reason) { psignal_internal(p, NULL, NULL, 0, signum, signal_reason); } void psignal_sigkill_with_reason(struct proc *p, struct os_reason *signal_reason) { psignal_internal(p, NULL, NULL, 0, SIGKILL, signal_reason); } void psignal_locked(proc_t p, int signum) { psignal_internal(p, NULL, NULL, PSIG_LOCKED, signum, NULL); } void psignal_vfork_with_reason(proc_t p, task_t new_task, thread_t thread, int signum, struct os_reason *signal_reason) { psignal_internal(p, new_task, thread, PSIG_VFORK, signum, signal_reason); } void psignal_vfork(proc_t p, task_t new_task, thread_t thread, int signum) { psignal_internal(p, new_task, thread, PSIG_VFORK, signum, NULL); } void psignal_uthread(thread_t thread, int signum) { psignal_internal(PROC_NULL, TASK_NULL, thread, PSIG_THREAD, signum, NULL); } /* same as psignal(), but prefer delivery to 'thread' if possible */ void psignal_try_thread(proc_t p, thread_t thread, int signum) { psignal_internal(p, NULL, thread, PSIG_TRY_THREAD, signum, NULL); } void psignal_try_thread_with_reason(proc_t p, thread_t thread, int signum, struct os_reason *signal_reason) { psignal_internal(p, TASK_NULL, thread, PSIG_TRY_THREAD, signum, signal_reason); } void psignal_thread_with_reason(proc_t p, thread_t thread, int signum, struct os_reason *signal_reason) { psignal_internal(p, TASK_NULL, thread, PSIG_THREAD, signum, signal_reason); } /* * If the current process has received a signal (should be caught or cause * termination, should interrupt current syscall), return the signal number. * Stop signals with default action are processed immediately, then cleared; * they aren't returned. This is checked after each entry to the system for * a syscall or trap (though this can usually be done without calling issignal * by checking the pending signal masks in the CURSIG macro.) The normal call * sequence is * * while (signum = CURSIG(curproc)) * postsig(signum); */ int issignal_locked(proc_t p) { int signum, mask, prop, sigbits; thread_t cur_act; struct uthread * ut; proc_t pp; kauth_cred_t my_cred; int retval = 0; uid_t r_uid; cur_act = current_thread(); #if SIGNAL_DEBUG if (rdebug_proc && (p == rdebug_proc)) { ram_printf(3); } #endif /* SIGNAL_DEBUG */ /* * Try to grab the signal lock. */ if (sig_try_locked(p) <= 0) { return 0; } proc_signalstart(p, 1); ut = get_bsdthread_info(cur_act); for (;;) { sigbits = ut->uu_siglist & ~ut->uu_sigmask; if (p->p_lflag & P_LPPWAIT) { sigbits &= ~stopsigmask; } if (sigbits == 0) { /* no signal to send */ retval = 0; goto out; } signum = ffs((unsigned int)sigbits); mask = sigmask(signum); prop = sigprop[signum]; /* * We should see pending but ignored signals * only if P_LTRACED was on when they were posted. */ if (mask & p->p_sigignore && (p->p_lflag & P_LTRACED) == 0) { ut->uu_siglist &= ~mask; continue; } if (p->p_lflag & P_LTRACED && (p->p_lflag & P_LPPWAIT) == 0) { /* * If traced, deliver the signal to the debugger, and wait to be * released. */ task_t task; p->p_xstat = signum; if (p->p_lflag & P_LSIGEXC) { p->sigwait = TRUE; p->sigwait_thread = cur_act; p->p_stat = SSTOP; OSBitAndAtomic(~((uint32_t)P_CONTINUED), &p->p_flag); p->p_lflag &= ~P_LWAITED; ut->uu_siglist &= ~mask; /* clear the current signal from the pending list */ proc_signalend(p, 1); proc_unlock(p); do_bsdexception(EXC_SOFTWARE, EXC_SOFT_SIGNAL, signum); proc_lock(p); proc_signalstart(p, 1); } else { proc_unlock(p); my_cred = kauth_cred_proc_ref(p); r_uid = kauth_cred_getruid(my_cred); kauth_cred_unref(&my_cred); /* * XXX Have to really stop for debuggers; * XXX stop() doesn't do the right thing. */ task = proc_task(p); task_suspend_internal(task); proc_lock(p); p->sigwait = TRUE; p->sigwait_thread = cur_act; p->p_stat = SSTOP; OSBitAndAtomic(~((uint32_t)P_CONTINUED), &p->p_flag); p->p_lflag &= ~P_LWAITED; ut->uu_siglist &= ~mask; proc_signalend(p, 1); proc_unlock(p); pp = proc_parentholdref(p); if (pp != PROC_NULL) { proc_lock(pp); pp->si_pid = proc_getpid(p); pp->p_xhighbits = p->p_xhighbits; p->p_xhighbits = 0; pp->si_status = p->p_xstat; pp->si_code = CLD_TRAPPED; pp->si_uid = r_uid; proc_unlock(pp); psignal(pp, SIGCHLD); proc_list_lock(); wakeup((caddr_t)pp); proc_parentdropref(pp, 1); proc_list_unlock(); } assert_wait((caddr_t)&p->sigwait, (THREAD_INTERRUPTIBLE)); thread_block(THREAD_CONTINUE_NULL); proc_lock(p); proc_signalstart(p, 1); } p->sigwait = FALSE; p->sigwait_thread = NULL; wakeup((caddr_t)&p->sigwait_thread); if (signum == SIGKILL || ut->uu_siglist & sigmask(SIGKILL)) { /* * Deliver a pending sigkill even if it's not the current signal. * Necessary for PT_KILL, which should not be delivered to the * debugger, but we can't differentiate it from any other KILL. */ signum = SIGKILL; goto deliver_sig; } /* We may have to quit. */ if (thread_should_abort(current_thread())) { retval = 0; goto out; } /* * If parent wants us to take the signal, * then it will leave it in p->p_xstat; * otherwise we just look for signals again. */ signum = p->p_xstat; if (signum == 0) { continue; } /* * Put the new signal into p_siglist. If the * signal is being masked, look for other signals. */ mask = sigmask(signum); ut->uu_siglist |= mask; if (ut->uu_sigmask & mask) { continue; } } /* * Decide whether the signal should be returned. * Return the signal's number, or fall through * to clear it from the pending mask. */ switch ((long)SIGACTION(p, signum)) { case (long)SIG_DFL: /* * 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) { struct pgrp * pg; proc_unlock(p); pg = proc_pgrp(p, NULL); if (p->p_lflag & P_LTRACED || (pg->pg_jobc == 0 && prop & SA_TTYSTOP)) { proc_lock(p); pgrp_rele(pg); break; /* ignore signal */ } pgrp_rele(pg); if (p->p_stat != SSTOP) { proc_lock(p); p->p_xstat = signum; p->p_stat = SSTOP; p->p_lflag &= ~P_LWAITED; proc_signalend(p, 1); proc_unlock(p); pp = proc_parentholdref(p); proc_signalstart(p, 0); stop(p, pp); if ((pp != PROC_NULL) && ((pp->p_flag & P_NOCLDSTOP) == 0)) { my_cred = kauth_cred_proc_ref(p); r_uid = kauth_cred_getruid(my_cred); kauth_cred_unref(&my_cred); proc_lock(pp); pp->si_pid = proc_getpid(p); pp->si_status = WEXITSTATUS(p->p_xstat); pp->si_code = CLD_STOPPED; pp->si_uid = r_uid; proc_unlock(pp); psignal(pp, SIGCHLD); } if (pp != PROC_NULL) { proc_parentdropref(pp, 0); } } proc_lock(p); break; } else if (prop & SA_IGNORE) { /* * Except for SIGCONT, shouldn't get here. * Default action is to ignore; drop it. */ break; /* ignore signal */ } else { goto deliver_sig; } case (long)SIG_IGN: /* * Masking above should prevent us ever trying * to take action on an ignored signal other * than SIGCONT, unless process is traced. */ if ((prop & SA_CONT) == 0 && (p->p_lflag & P_LTRACED) == 0) { printf("issignal\n"); } break; /* ignore signal */ default: /* This signal has an action - deliver it. */ goto deliver_sig; } /* If we dropped through, the signal was ignored - remove it from pending list. */ ut->uu_siglist &= ~mask; } /* for(;;) */ /* NOTREACHED */ deliver_sig: ut->uu_siglist &= ~mask; retval = signum; out: proc_signalend(p, 1); return retval; } /* called from _sleep */ int CURSIG(proc_t p) { int signum, mask, prop, sigbits; thread_t cur_act; struct uthread * ut; int retnum = 0; cur_act = current_thread(); ut = get_bsdthread_info(cur_act); if (ut->uu_siglist == 0) { return 0; } if (((ut->uu_siglist & ~ut->uu_sigmask) == 0) && ((p->p_lflag & P_LTRACED) == 0)) { return 0; } sigbits = ut->uu_siglist & ~ut->uu_sigmask; for (;;) { if (p->p_lflag & P_LPPWAIT) { sigbits &= ~stopsigmask; } if (sigbits == 0) { /* no signal to send */ return retnum; } signum = ffs((unsigned int)sigbits); mask = sigmask(signum); prop = sigprop[signum]; sigbits &= ~mask; /* take the signal out */ /* * We should see pending but ignored signals * only if P_LTRACED was on when they were posted. */ if (mask & p->p_sigignore && (p->p_lflag & P_LTRACED) == 0) { continue; } if (p->p_lflag & P_LTRACED && (p->p_lflag & P_LPPWAIT) == 0) { return signum; } /* * Decide whether the signal should be returned. * Return the signal's number, or fall through * to clear it from the pending mask. */ switch ((long)SIGACTION(p, signum)) { case (long)SIG_DFL: /* * 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) { struct pgrp *pg; pg = proc_pgrp(p, NULL); if (p->p_lflag & P_LTRACED || (pg->pg_jobc == 0 && prop & SA_TTYSTOP)) { pgrp_rele(pg); break; /* == ignore */ } pgrp_rele(pg); retnum = signum; break; } else if (prop & SA_IGNORE) { /* * Except for SIGCONT, shouldn't get here. * Default action is to ignore; drop it. */ break; /* == ignore */ } else { return signum; } /*NOTREACHED*/ case (long)SIG_IGN: /* * Masking above should prevent us ever trying * to take action on an ignored signal other * than SIGCONT, unless process is traced. */ if ((prop & SA_CONT) == 0 && (p->p_lflag & P_LTRACED) == 0) { printf("issignal\n"); } break; /* == ignore */ default: /* * This signal has an action, let * postsig() process it. */ return signum; } } /* NOTREACHED */ } /* * Put the argument process into the stopped state and notify the parent * via wakeup. Signals are handled elsewhere. The process must not be * on the run queue. */ static void stop(proc_t p, proc_t parent) { OSBitAndAtomic(~((uint32_t)P_CONTINUED), &p->p_flag); if ((parent != PROC_NULL) && (parent->p_stat != SSTOP)) { proc_list_lock(); wakeup((caddr_t)parent); proc_list_unlock(); } (void) task_suspend_internal(proc_task(p)); } /* * Take the action for the specified signal * from the current set of pending signals. */ void postsig_locked(int signum) { proc_t p = current_proc(); struct sigacts *ps = &p->p_sigacts; user_addr_t catcher; uint32_t code; int mask, returnmask; struct uthread * ut; os_reason_t ut_exit_reason = OS_REASON_NULL; int coredump_flags = 0; #if DIAGNOSTIC if (signum == 0) { panic("postsig"); } /* * This must be called on master cpu */ if (cpu_number() != master_cpu) { panic("psig not on master"); } #endif /* * Try to grab the signal lock. */ if (sig_try_locked(p) <= 0) { return; } proc_signalstart(p, 1); ut = current_uthread(); mask = sigmask(signum); ut->uu_siglist &= ~mask; catcher = SIGACTION(p, signum); if (catcher == SIG_DFL) { /* * Default catcher, where the default is to kill * the process. (Other cases were ignored above.) */ /* * exit_with_reason() below will consume a reference to the thread's exit reason, so we take another * reference so the thread still has one even after we call exit_with_reason(). The thread's reference will * ultimately be destroyed in uthread_cleanup(). */ ut_exit_reason = ut->uu_exit_reason; os_reason_ref(ut_exit_reason); p->p_acflag |= AXSIG; if (sigprop[signum] & SA_CORE) { p->p_sigacts.ps_sig = signum; proc_signalend(p, 1); proc_unlock(p); if (task_is_driver(proc_task(p))) { coredump_flags |= COREDUMP_FULLFSYNC; } #if CONFIG_COREDUMP if (coredump(p, 0, coredump_flags) == 0) { signum |= WCOREFLAG; } #endif } else { proc_signalend(p, 1); proc_unlock(p); } #if CONFIG_DTRACE bzero((caddr_t)&(ut->t_dtrace_siginfo), sizeof(ut->t_dtrace_siginfo)); ut->t_dtrace_siginfo.si_signo = signum; ut->t_dtrace_siginfo.si_pid = p->si_pid; ut->t_dtrace_siginfo.si_uid = p->si_uid; ut->t_dtrace_siginfo.si_status = WEXITSTATUS(p->si_status); /* Fire DTrace proc:::fault probe when signal is generated by hardware. */ switch (signum) { case SIGILL: case SIGBUS: case SIGSEGV: case SIGFPE: case SIGTRAP: DTRACE_PROC2(fault, int, (int)(ut->uu_code), siginfo_t *, &(ut->t_dtrace_siginfo)); break; default: break; } DTRACE_PROC3(signal__handle, int, signum, siginfo_t *, &(ut->t_dtrace_siginfo), void (*)(void), SIG_DFL); #endif KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_FRCEXIT) | DBG_FUNC_NONE, proc_getpid(p), W_EXITCODE(0, signum), 3, 0, 0); exit_with_reason(p, W_EXITCODE(0, signum), (int *)NULL, TRUE, TRUE, 0, ut_exit_reason); proc_lock(p); return; } else { /* * If we get here, the signal must be caught. */ #if DIAGNOSTIC if (catcher == SIG_IGN || (ut->uu_sigmask & mask)) { log(LOG_WARNING, "postsig: processing masked or ignored signal\n"); } #endif /* * Set the new mask value and also defer further * occurences of this signal. * * Special case: user has done a sigpause. Here the * current mask is not of interest, but rather the * mask from before the sigpause is what we want * restored after the signal processing is completed. */ if (ut->uu_flag & UT_SAS_OLDMASK) { returnmask = ut->uu_oldmask; ut->uu_flag &= ~UT_SAS_OLDMASK; ut->uu_oldmask = 0; } else { returnmask = ut->uu_sigmask; } ut->uu_sigmask |= ps->ps_catchmask[signum]; if ((ps->ps_signodefer & mask) == 0) { ut->uu_sigmask |= mask; } sigset_t siginfo = ps->ps_siginfo; if ((signum != SIGILL) && (signum != SIGTRAP) && (ps->ps_sigreset & mask)) { if ((signum != SIGCONT) && (sigprop[signum] & SA_IGNORE)) { p->p_sigignore |= mask; } if (SIGACTION(p, signum) != SIG_DFL) { proc_set_sigact(p, signum, SIG_DFL); } ps->ps_siginfo &= ~mask; ps->ps_signodefer &= ~mask; } if (ps->ps_sig != signum) { code = 0; } else { code = ps->ps_code; ps->ps_code = 0; } OSIncrementAtomicLong(&p->p_stats->p_ru.ru_nsignals); sendsig(p, catcher, signum, returnmask, code, siginfo); } proc_signalend(p, 1); } /* * Attach a signal knote to the list of knotes for this process. * * Signal knotes share the knote list with proc knotes. This * could be avoided by using a signal-specific knote list, but * probably isn't worth the trouble. */ static int filt_sigattach(struct knote *kn, __unused struct kevent_qos_s *kev) { proc_t p = current_proc(); /* can attach only to oneself */ proc_klist_lock(); kn->kn_proc = p; kn->kn_flags |= EV_CLEAR; /* automatically set */ kn->kn_sdata = 0; /* incoming data is ignored */ KNOTE_ATTACH(&p->p_klist, kn); proc_klist_unlock(); /* edge-triggered events can't have fired before we attached */ return 0; } /* * remove the knote from the process list, if it hasn't already * been removed by exit processing. */ static void filt_sigdetach(struct knote *kn) { proc_t p; proc_klist_lock(); p = kn->kn_proc; if (p != NULL) { kn->kn_proc = NULL; KNOTE_DETACH(&p->p_klist, kn); } proc_klist_unlock(); } /* * Post an event to the signal filter. Because we share the same list * as process knotes, we have to filter out and handle only signal events. * * We assume that we process fdt_invalidate() before we post the NOTE_EXIT for * a process during exit. Therefore, since signal filters can only be * set up "in-process", we should have already torn down the kqueue * hosting the EVFILT_SIGNAL knote and should never see NOTE_EXIT. */ static int filt_signal(struct knote *kn, long hint) { if (hint & NOTE_SIGNAL) { hint &= ~NOTE_SIGNAL; if (kn->kn_id == (unsigned int)hint) { kn->kn_hook32++; } } else if (hint & NOTE_EXIT) { panic("filt_signal: detected NOTE_EXIT event"); } return kn->kn_hook32 != 0; } static int filt_signaltouch(struct knote *kn, struct kevent_qos_s *kev) { #pragma unused(kev) int res; proc_klist_lock(); /* * No data to save - just capture if it is already fired */ res = (kn->kn_hook32 > 0); proc_klist_unlock(); return res; } static int filt_signalprocess(struct knote *kn, struct kevent_qos_s *kev) { int res = 0; /* * Snapshot the event data. */ proc_klist_lock(); if (kn->kn_hook32) { knote_fill_kevent(kn, kev, kn->kn_hook32); kn->kn_hook32 = 0; res = 1; } proc_klist_unlock(); return res; } void bsd_ast(thread_t thread) { proc_t p = current_proc(); struct uthread *ut = get_bsdthread_info(thread); int signum; static int bsd_init_done = 0; if (p == NULL) { return; } if (timerisset(&p->p_vtimer_user.it_value)) { uint32_t microsecs; task_vtimer_update(proc_task(p), TASK_VTIMER_USER, µsecs); if (!itimerdecr(p, &p->p_vtimer_user, microsecs)) { if (timerisset(&p->p_vtimer_user.it_value)) { task_vtimer_set(proc_task(p), TASK_VTIMER_USER); } else { task_vtimer_clear(proc_task(p), TASK_VTIMER_USER); } psignal_try_thread(p, thread, SIGVTALRM); } } if (timerisset(&p->p_vtimer_prof.it_value)) { uint32_t microsecs; task_vtimer_update(proc_task(p), TASK_VTIMER_PROF, µsecs); if (!itimerdecr(p, &p->p_vtimer_prof, microsecs)) { if (timerisset(&p->p_vtimer_prof.it_value)) { task_vtimer_set(proc_task(p), TASK_VTIMER_PROF); } else { task_vtimer_clear(proc_task(p), TASK_VTIMER_PROF); } psignal_try_thread(p, thread, SIGPROF); } } if (timerisset(&p->p_rlim_cpu)) { struct timeval tv; task_vtimer_update(proc_task(p), TASK_VTIMER_RLIM, (uint32_t *) &tv.tv_usec); proc_spinlock(p); if (p->p_rlim_cpu.tv_sec > 0 || p->p_rlim_cpu.tv_usec > tv.tv_usec) { tv.tv_sec = 0; timersub(&p->p_rlim_cpu, &tv, &p->p_rlim_cpu); proc_spinunlock(p); } else { timerclear(&p->p_rlim_cpu); proc_spinunlock(p); task_vtimer_clear(proc_task(p), TASK_VTIMER_RLIM); psignal_try_thread(p, thread, SIGXCPU); } } #if CONFIG_DTRACE if (ut->t_dtrace_sig) { uint8_t dt_action_sig = ut->t_dtrace_sig; ut->t_dtrace_sig = 0; psignal(p, dt_action_sig); } if (ut->t_dtrace_stop) { ut->t_dtrace_stop = 0; proc_lock(p); p->p_dtrace_stop = 1; proc_unlock(p); (void)task_suspend_internal(proc_task(p)); } if (ut->t_dtrace_resumepid) { proc_t resumeproc = proc_find((int)ut->t_dtrace_resumepid); ut->t_dtrace_resumepid = 0; if (resumeproc != PROC_NULL) { proc_lock(resumeproc); /* We only act on processes stopped by dtrace */ if (resumeproc->p_dtrace_stop) { resumeproc->p_dtrace_stop = 0; proc_unlock(resumeproc); task_resume_internal(proc_task(resumeproc)); } else { proc_unlock(resumeproc); } proc_rele(resumeproc); } } #endif /* CONFIG_DTRACE */ proc_lock(p); if (CHECK_SIGNALS(p, current_thread(), ut)) { while ((signum = issignal_locked(p))) { postsig_locked(signum); } } proc_unlock(p); if (!bsd_init_done) { bsd_init_done = 1; bsdinit_task(); } } /* ptrace set runnable */ void pt_setrunnable(proc_t p) { task_t task; task = proc_task(p); if (p->p_lflag & P_LTRACED) { proc_lock(p); p->p_stat = SRUN; proc_unlock(p); if (p->sigwait) { wakeup((caddr_t)&(p->sigwait)); if ((p->p_lflag & P_LSIGEXC) == 0) { // 5878479 task_release(task); } } } } kern_return_t do_bsdexception( int exc, int code, int sub) { mach_exception_data_type_t codes[EXCEPTION_CODE_MAX]; codes[0] = code; codes[1] = sub; return bsd_exception(exc, codes, 2); } int proc_pendingsignals(proc_t p, sigset_t mask) { struct uthread * uth; sigset_t bits = 0; proc_lock(p); /* If the process is in proc exit return no signal info */ if (p->p_lflag & P_LPEXIT) { goto out; } bits = 0; TAILQ_FOREACH(uth, &p->p_uthlist, uu_list) { bits |= (((uth->uu_siglist & ~uth->uu_sigmask) & ~p->p_sigignore) & mask); } out: proc_unlock(p); return bits; } int thread_issignal(proc_t p, thread_t th, sigset_t mask) { struct uthread * uth; sigset_t bits = 0; proc_lock(p); uth = (struct uthread *)get_bsdthread_info(th); if (uth) { bits = (((uth->uu_siglist & ~uth->uu_sigmask) & ~p->p_sigignore) & mask); } proc_unlock(p); return bits; } /* * Allow external reads of the sigprop array. */ int hassigprop(int sig, int prop) { return sigprop[sig] & prop; } void pgsigio(pid_t pgid, int sig) { proc_t p = PROC_NULL; if (pgid < 0) { gsignal(-(pgid), sig); } else if (pgid > 0 && (p = proc_find(pgid)) != 0) { psignal(p, sig); } if (p != PROC_NULL) { proc_rele(p); } } void proc_signalstart(proc_t p, int locked) { if (!locked) { proc_lock(p); } if (p->p_signalholder == current_thread()) { panic("proc_signalstart: thread attempting to signal a process for which it holds the signal lock"); } p->p_sigwaitcnt++; while ((p->p_lflag & P_LINSIGNAL) == P_LINSIGNAL) { msleep(&p->p_sigmask, &p->p_mlock, 0, "proc_signstart", NULL); } p->p_sigwaitcnt--; p->p_lflag |= P_LINSIGNAL; p->p_signalholder = current_thread(); if (!locked) { proc_unlock(p); } } void proc_signalend(proc_t p, int locked) { if (!locked) { proc_lock(p); } p->p_lflag &= ~P_LINSIGNAL; if (p->p_sigwaitcnt > 0) { wakeup(&p->p_sigmask); } p->p_signalholder = NULL; if (!locked) { proc_unlock(p); } } void sig_lock_to_exit(proc_t p) { thread_t self = current_thread(); p->exit_thread = self; proc_unlock(p); task_hold_and_wait(proc_task(p)); proc_lock(p); } int sig_try_locked(proc_t p) { thread_t self = current_thread(); while (p->sigwait || p->exit_thread) { if (p->exit_thread) { return 0; } msleep((caddr_t)&p->sigwait_thread, &p->p_mlock, PCATCH | PDROP, 0, 0); if (thread_should_abort(self)) { /* * Terminate request - clean up. */ proc_lock(p); return -1; } proc_lock(p); } return 1; }