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b47cac74e3
* hurd/hurdsig.c (_hurd_internal_post_signal): If a hurd_signal_preemptor matches but its `preemptor' field is null, use its `handler' field directly. This is to comply with behavior documented in <hurd/sigpreempt.h>.
1334 lines
40 KiB
C
1334 lines
40 KiB
C
/* Copyright (C) 1991,92,93,94,95,96,97,98,99 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <stdlib.h>
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#include <stdio.h>
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#include <hurd.h>
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#include <hurd/signal.h>
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#include <cthreads.h> /* For `struct mutex'. */
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#include <string.h>
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#include <hurd/id.h>
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#include "hurdfault.h"
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#include "hurdmalloc.h" /* XXX */
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const char *_hurdsig_getenv (const char *);
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struct mutex _hurd_siglock;
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int _hurd_stopped;
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/* Port that receives signals and other miscellaneous messages. */
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mach_port_t _hurd_msgport;
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/* Thread listening on it. */
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thread_t _hurd_msgport_thread;
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/* Thread which receives task-global signals. */
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thread_t _hurd_sigthread;
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/* These are set up by _hurdsig_init. */
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unsigned long int __hurd_sigthread_stack_base;
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unsigned long int __hurd_sigthread_stack_end;
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unsigned long int *__hurd_sigthread_variables;
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/* Linked-list of per-thread signal state. */
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struct hurd_sigstate *_hurd_sigstates;
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/* Timeout for RPC's after interrupt_operation. */
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mach_msg_timeout_t _hurd_interrupted_rpc_timeout = 3000;
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static void
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default_sigaction (struct sigaction actions[NSIG])
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{
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int signo;
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__sigemptyset (&actions[0].sa_mask);
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actions[0].sa_flags = SA_RESTART;
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actions[0].sa_handler = SIG_DFL;
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for (signo = 1; signo < NSIG; ++signo)
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actions[signo] = actions[0];
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}
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struct hurd_sigstate *
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_hurd_thread_sigstate (thread_t thread)
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{
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struct hurd_sigstate *ss;
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__mutex_lock (&_hurd_siglock);
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for (ss = _hurd_sigstates; ss != NULL; ss = ss->next)
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if (ss->thread == thread)
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break;
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if (ss == NULL)
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{
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ss = malloc (sizeof (*ss));
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if (ss == NULL)
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__libc_fatal ("hurd: Can't allocate thread sigstate\n");
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ss->thread = thread;
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__spin_lock_init (&ss->lock);
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/* Initialize default state. */
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__sigemptyset (&ss->blocked);
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__sigemptyset (&ss->pending);
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memset (&ss->sigaltstack, 0, sizeof (ss->sigaltstack));
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ss->preemptors = NULL;
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ss->suspended = 0;
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ss->intr_port = MACH_PORT_NULL;
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ss->context = NULL;
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/* Initialize the sigaction vector from the default signal receiving
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thread's state, and its from the system defaults. */
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if (thread == _hurd_sigthread)
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default_sigaction (ss->actions);
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else
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{
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struct hurd_sigstate *s;
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for (s = _hurd_sigstates; s != NULL; s = s->next)
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if (s->thread == _hurd_sigthread)
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break;
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if (s)
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{
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__spin_lock (&s->lock);
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memcpy (ss->actions, s->actions, sizeof (s->actions));
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__spin_unlock (&s->lock);
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}
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else
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default_sigaction (ss->actions);
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}
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ss->next = _hurd_sigstates;
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_hurd_sigstates = ss;
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}
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__mutex_unlock (&_hurd_siglock);
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return ss;
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}
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/* Signal delivery itself is on this page. */
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#include <hurd/fd.h>
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#include <hurd/crash.h>
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#include <hurd/paths.h>
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#include <setjmp.h>
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#include <fcntl.h>
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#include <sys/wait.h>
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#include "thread_state.h"
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#include <hurd/msg_server.h>
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#include <hurd/msg_reply.h> /* For __msg_sig_post_reply. */
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#include <hurd/interrupt.h>
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#include <assert.h>
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#include <unistd.h>
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int _hurd_core_limit; /* XXX */
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/* Call the crash dump server to mummify us before we die.
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Returns nonzero if a core file was written. */
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static int
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write_corefile (int signo, const struct hurd_signal_detail *detail)
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{
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error_t err;
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mach_port_t coreserver;
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file_t file, coredir;
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const char *name;
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/* XXX RLIMIT_CORE:
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When we have a protocol to make the server return an error
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for RLIMIT_FSIZE, then tell the corefile fs server the RLIMIT_CORE
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value in place of the RLIMIT_FSIZE value. */
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/* First get a port to the core dumping server. */
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coreserver = MACH_PORT_NULL;
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name = _hurdsig_getenv ("CRASHSERVER");
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if (name != NULL)
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coreserver = __file_name_lookup (name, 0, 0);
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if (coreserver == MACH_PORT_NULL)
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coreserver = __file_name_lookup (_SERVERS_CRASH, 0, 0);
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if (coreserver == MACH_PORT_NULL)
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return 0;
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/* Get a port to the directory where the new core file will reside. */
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file = MACH_PORT_NULL;
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name = _hurdsig_getenv ("COREFILE");
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if (name == NULL)
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name = "core";
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coredir = __file_name_split (name, (char **) &name);
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if (coredir != MACH_PORT_NULL)
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/* Create the new file, but don't link it into the directory yet. */
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__dir_mkfile (coredir, O_WRONLY|O_CREAT,
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0600 & ~_hurd_umask, /* XXX ? */
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&file);
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/* Call the core dumping server to write the core file. */
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err = __crash_dump_task (coreserver,
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__mach_task_self (),
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file,
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signo, detail->code, detail->error,
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detail->exc, detail->exc_code, detail->exc_subcode,
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_hurd_ports[INIT_PORT_CTTYID].port,
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MACH_MSG_TYPE_COPY_SEND);
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__mach_port_deallocate (__mach_task_self (), coreserver);
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if (! err && file != MACH_PORT_NULL)
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/* The core dump into FILE succeeded, so now link it into the
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directory. */
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err = __dir_link (file, coredir, name, 1);
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__mach_port_deallocate (__mach_task_self (), file);
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__mach_port_deallocate (__mach_task_self (), coredir);
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return !err && file != MACH_PORT_NULL;
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}
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/* The lowest-numbered thread state flavor value is 1,
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so we use bit 0 in machine_thread_all_state.set to
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record whether we have done thread_abort. */
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#define THREAD_ABORTED 1
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/* SS->thread is suspended. Abort the thread and get its basic state. */
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static void
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abort_thread (struct hurd_sigstate *ss, struct machine_thread_all_state *state,
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void (*reply) (void))
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{
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if (!(state->set & THREAD_ABORTED))
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{
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error_t err = __thread_abort (ss->thread);
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assert_perror (err);
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/* Clear all thread state flavor set bits, because thread_abort may
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have changed the state. */
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state->set = THREAD_ABORTED;
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}
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if (reply)
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(*reply) ();
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machine_get_basic_state (ss->thread, state);
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}
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/* Find the location of the MiG reply port cell in use by the thread whose
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state is described by THREAD_STATE. If SIGTHREAD is nonzero, make sure
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that this location can be set without faulting, or else return NULL. */
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static mach_port_t *
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interrupted_reply_port_location (struct machine_thread_all_state *thread_state,
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int sigthread)
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{
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mach_port_t *portloc = (mach_port_t *) __hurd_threadvar_location_from_sp
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(_HURD_THREADVAR_MIG_REPLY, (void *) thread_state->basic.SP);
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if (sigthread && _hurdsig_catch_memory_fault (portloc))
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/* Faulted trying to read the stack. */
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return NULL;
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/* Fault now if this pointer is bogus. */
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*(volatile mach_port_t *) portloc = *portloc;
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if (sigthread)
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_hurdsig_end_catch_fault ();
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return portloc;
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}
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#include <hurd/sigpreempt.h>
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#include "intr-msg.h"
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/* Timeout on interrupt_operation calls. */
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mach_msg_timeout_t _hurdsig_interrupt_timeout = 1000;
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/* SS->thread is suspended.
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Abort any interruptible RPC operation the thread is doing.
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This uses only the constant member SS->thread and the unlocked, atomically
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set member SS->intr_port, so no locking is needed.
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If successfully sent an interrupt_operation and therefore the thread should
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wait for its pending RPC to return (possibly EINTR) before taking the
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incoming signal, returns the reply port to be received on. Otherwise
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returns MACH_PORT_NULL.
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SIGNO is used to find the applicable SA_RESTART bit. If SIGNO is zero,
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the RPC fails with EINTR instead of restarting (thread_cancel).
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*STATE_CHANGE is set nonzero if STATE->basic was modified and should
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be applied back to the thread if it might ever run again, else zero. */
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mach_port_t
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_hurdsig_abort_rpcs (struct hurd_sigstate *ss, int signo, int sigthread,
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struct machine_thread_all_state *state, int *state_change,
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void (*reply) (void))
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{
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extern const void _hurd_intr_rpc_msg_in_trap;
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mach_port_t rcv_port = MACH_PORT_NULL;
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mach_port_t intr_port;
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*state_change = 0;
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intr_port = ss->intr_port;
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if (intr_port == MACH_PORT_NULL)
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/* No interruption needs done. */
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return MACH_PORT_NULL;
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/* Abort the thread's kernel context, so any pending message send or
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receive completes immediately or aborts. */
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abort_thread (ss, state, reply);
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if (state->basic.PC < (natural_t) &_hurd_intr_rpc_msg_in_trap)
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{
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/* The thread is about to do the RPC, but hasn't yet entered
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mach_msg. Mutate the thread's state so it knows not to try
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the RPC. */
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INTR_MSG_BACK_OUT (&state->basic);
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MACHINE_THREAD_STATE_SET_PC (&state->basic,
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&_hurd_intr_rpc_msg_in_trap);
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state->basic.SYSRETURN = MACH_SEND_INTERRUPTED;
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*state_change = 1;
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}
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else if (state->basic.PC == (natural_t) &_hurd_intr_rpc_msg_in_trap &&
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/* The thread was blocked in the system call. After thread_abort,
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the return value register indicates what state the RPC was in
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when interrupted. */
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state->basic.SYSRETURN == MACH_RCV_INTERRUPTED)
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{
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/* The RPC request message was sent and the thread was waiting for
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the reply message; now the message receive has been aborted, so
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the mach_msg call will return MACH_RCV_INTERRUPTED. We must tell
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the server to interrupt the pending operation. The thread must
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wait for the reply message before running the signal handler (to
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guarantee that the operation has finished being interrupted), so
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our nonzero return tells the trampoline code to finish the message
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receive operation before running the handler. */
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mach_port_t *reply = interrupted_reply_port_location (state,
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sigthread);
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error_t err = __interrupt_operation (intr_port, _hurdsig_interrupt_timeout);
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if (err)
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{
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if (reply)
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{
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/* The interrupt didn't work.
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Destroy the receive right the thread is blocked on. */
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__mach_port_destroy (__mach_task_self (), *reply);
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*reply = MACH_PORT_NULL;
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}
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/* The system call return value register now contains
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MACH_RCV_INTERRUPTED; when mach_msg resumes, it will retry the
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call. Since we have just destroyed the receive right, the
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retry will fail with MACH_RCV_INVALID_NAME. Instead, just
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change the return value here to EINTR so mach_msg will not
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retry and the EINTR error code will propagate up. */
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state->basic.SYSRETURN = EINTR;
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*state_change = 1;
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}
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else if (reply)
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rcv_port = *reply;
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/* All threads whose RPCs were interrupted by the interrupt_operation
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call above will retry their RPCs unless we clear SS->intr_port.
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So we clear it for the thread taking a signal when SA_RESTART is
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clear, so that its call returns EINTR. */
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if (! signo || !(ss->actions[signo].sa_flags & SA_RESTART))
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ss->intr_port = MACH_PORT_NULL;
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}
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return rcv_port;
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}
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/* Abort the RPCs being run by all threads but this one;
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all other threads should be suspended. If LIVE is nonzero, those
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threads may run again, so they should be adjusted as necessary to be
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happy when resumed. STATE is clobbered as a scratch area; its initial
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contents are ignored, and its contents on return are not useful. */
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static void
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abort_all_rpcs (int signo, struct machine_thread_all_state *state, int live)
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{
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/* We can just loop over the sigstates. Any thread doing something
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interruptible must have one. We needn't bother locking because all
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other threads are stopped. */
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struct hurd_sigstate *ss;
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size_t nthreads;
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mach_port_t *reply_ports;
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/* First loop over the sigstates to count them.
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We need to know how big a vector we will need for REPLY_PORTS. */
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nthreads = 0;
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for (ss = _hurd_sigstates; ss != NULL; ss = ss->next)
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++nthreads;
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reply_ports = alloca (nthreads * sizeof *reply_ports);
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nthreads = 0;
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for (ss = _hurd_sigstates; ss != NULL; ss = ss->next, ++nthreads)
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if (ss->thread == _hurd_msgport_thread)
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reply_ports[nthreads] = MACH_PORT_NULL;
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else
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{
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int state_changed;
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state->set = 0; /* Reset scratch area. */
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/* Abort any operation in progress with interrupt_operation.
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Record the reply port the thread is waiting on.
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We will wait for all the replies below. */
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reply_ports[nthreads] = _hurdsig_abort_rpcs (ss, signo, 1,
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state, &state_changed,
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NULL);
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if (live)
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{
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if (reply_ports[nthreads] != MACH_PORT_NULL)
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{
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/* We will wait for the reply to this RPC below, so the
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thread must issue a new RPC rather than waiting for the
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reply to the one it sent. */
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state->basic.SYSRETURN = EINTR;
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state_changed = 1;
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}
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if (state_changed)
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/* Aborting the RPC needed to change this thread's state,
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and it might ever run again. So write back its state. */
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__thread_set_state (ss->thread, MACHINE_THREAD_STATE_FLAVOR,
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(natural_t *) &state->basic,
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MACHINE_THREAD_STATE_COUNT);
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}
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}
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/* Wait for replies from all the successfully interrupted RPCs. */
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while (nthreads-- > 0)
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if (reply_ports[nthreads] != MACH_PORT_NULL)
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{
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error_t err;
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mach_msg_header_t head;
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err = __mach_msg (&head, MACH_RCV_MSG|MACH_RCV_TIMEOUT, 0, sizeof head,
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reply_ports[nthreads],
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_hurd_interrupted_rpc_timeout, MACH_PORT_NULL);
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switch (err)
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{
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case MACH_RCV_TIMED_OUT:
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case MACH_RCV_TOO_LARGE:
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break;
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||
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default:
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assert_perror (err);
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}
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||
}
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||
}
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||
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struct hurd_signal_preemptor *_hurdsig_preemptors = 0;
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||
sigset_t _hurdsig_preempted_set;
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||
|
||
/* XXX temporary to deal with spelling fix */
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||
weak_alias (_hurdsig_preemptors, _hurdsig_preempters)
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||
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||
/* Mask of stop signals. */
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||
#define STOPSIGS (sigmask (SIGTTIN) | sigmask (SIGTTOU) | \
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sigmask (SIGSTOP) | sigmask (SIGTSTP))
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||
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||
/* Deliver a signal. SS is not locked. */
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||
void
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||
_hurd_internal_post_signal (struct hurd_sigstate *ss,
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||
int signo, struct hurd_signal_detail *detail,
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||
mach_port_t reply_port,
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||
mach_msg_type_name_t reply_port_type,
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||
int untraced)
|
||
{
|
||
error_t err;
|
||
struct machine_thread_all_state thread_state;
|
||
enum { stop, ignore, core, term, handle } act;
|
||
sighandler_t handler;
|
||
sigset_t pending;
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||
int ss_suspended;
|
||
|
||
/* Reply to this sig_post message. */
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||
__typeof (__msg_sig_post_reply) *reply_rpc
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||
= (untraced ? __msg_sig_post_untraced_reply : __msg_sig_post_reply);
|
||
void reply (void)
|
||
{
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||
error_t err;
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||
if (reply_port == MACH_PORT_NULL)
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||
return;
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||
err = (*reply_rpc) (reply_port, reply_port_type, 0);
|
||
reply_port = MACH_PORT_NULL;
|
||
if (err != MACH_SEND_INVALID_DEST) /* Ignore dead reply port. */
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||
assert_perror (err);
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||
}
|
||
|
||
/* Mark the signal as pending. */
|
||
void mark_pending (void)
|
||
{
|
||
__sigaddset (&ss->pending, signo);
|
||
/* Save the details to be given to the handler when SIGNO is
|
||
unblocked. */
|
||
ss->pending_data[signo] = *detail;
|
||
}
|
||
|
||
/* Suspend the process with SIGNO. */
|
||
void suspend (void)
|
||
{
|
||
/* Stop all other threads and mark ourselves stopped. */
|
||
__USEPORT (PROC,
|
||
({
|
||
/* Hold the siglock while stopping other threads to be
|
||
sure it is not held by another thread afterwards. */
|
||
__mutex_lock (&_hurd_siglock);
|
||
__proc_dostop (port, _hurd_msgport_thread);
|
||
__mutex_unlock (&_hurd_siglock);
|
||
abort_all_rpcs (signo, &thread_state, 1);
|
||
reply ();
|
||
__proc_mark_stop (port, signo, detail->code);
|
||
}));
|
||
_hurd_stopped = 1;
|
||
}
|
||
/* Resume the process after a suspension. */
|
||
void resume (void)
|
||
{
|
||
/* Resume the process from being stopped. */
|
||
thread_t *threads;
|
||
mach_msg_type_number_t nthreads, i;
|
||
error_t err;
|
||
|
||
if (! _hurd_stopped)
|
||
return;
|
||
|
||
/* Tell the proc server we are continuing. */
|
||
__USEPORT (PROC, __proc_mark_cont (port));
|
||
/* Fetch ports to all our threads and resume them. */
|
||
err = __task_threads (__mach_task_self (), &threads, &nthreads);
|
||
assert_perror (err);
|
||
for (i = 0; i < nthreads; ++i)
|
||
{
|
||
if (threads[i] != _hurd_msgport_thread &&
|
||
(act != handle || threads[i] != ss->thread))
|
||
{
|
||
err = __thread_resume (threads[i]);
|
||
assert_perror (err);
|
||
}
|
||
err = __mach_port_deallocate (__mach_task_self (),
|
||
threads[i]);
|
||
assert_perror (err);
|
||
}
|
||
__vm_deallocate (__mach_task_self (),
|
||
(vm_address_t) threads,
|
||
nthreads * sizeof *threads);
|
||
_hurd_stopped = 0;
|
||
if (act == handle)
|
||
/* The thread that will run the handler is already suspended. */
|
||
ss_suspended = 1;
|
||
}
|
||
|
||
if (signo == 0)
|
||
{
|
||
if (untraced)
|
||
/* This is PTRACE_CONTINUE. */
|
||
resume ();
|
||
|
||
/* This call is just to check for pending signals. */
|
||
__spin_lock (&ss->lock);
|
||
goto check_pending_signals;
|
||
}
|
||
|
||
post_signal:
|
||
|
||
thread_state.set = 0; /* We know nothing. */
|
||
|
||
__spin_lock (&ss->lock);
|
||
|
||
/* Check for a preempted signal. Preempted signals can arrive during
|
||
critical sections. */
|
||
{
|
||
inline sighandler_t try_preemptor (struct hurd_signal_preemptor *pe)
|
||
{ /* PE cannot be null. */
|
||
do
|
||
{
|
||
if (HURD_PREEMPT_SIGNAL_P (pe, signo, detail->code))
|
||
{
|
||
if (pe->preemptor)
|
||
{
|
||
sighandler_t handler = (*pe->preemptor) (pe, ss,
|
||
&signo, detail);
|
||
if (handler != SIG_ERR)
|
||
return handler;
|
||
}
|
||
else
|
||
return pe->handler;
|
||
}
|
||
pe = pe->next;
|
||
} while (pe != 0);
|
||
return SIG_ERR;
|
||
}
|
||
|
||
handler = ss->preemptors ? try_preemptor (ss->preemptors) : SIG_ERR;
|
||
|
||
/* If no thread-specific preemptor, check for a global one. */
|
||
if (handler == SIG_ERR && (__sigmask (signo) & _hurdsig_preempted_set))
|
||
{
|
||
__mutex_lock (&_hurd_siglock);
|
||
handler = try_preemptor (_hurdsig_preemptors);
|
||
__mutex_unlock (&_hurd_siglock);
|
||
}
|
||
}
|
||
|
||
ss_suspended = 0;
|
||
|
||
if (handler == SIG_IGN)
|
||
/* Ignore the signal altogether. */
|
||
act = ignore;
|
||
if (handler != SIG_ERR)
|
||
/* Run the preemption-provided handler. */
|
||
act = handle;
|
||
else
|
||
{
|
||
/* No preemption. Do normal handling. */
|
||
|
||
if (!untraced && __sigismember (&_hurdsig_traced, signo))
|
||
{
|
||
/* We are being traced. Stop to tell the debugger of the signal. */
|
||
if (_hurd_stopped)
|
||
/* Already stopped. Mark the signal as pending;
|
||
when resumed, we will notice it and stop again. */
|
||
mark_pending ();
|
||
else
|
||
suspend ();
|
||
__spin_unlock (&ss->lock);
|
||
reply ();
|
||
return;
|
||
}
|
||
|
||
handler = ss->actions[signo].sa_handler;
|
||
|
||
if (handler == SIG_DFL)
|
||
/* Figure out the default action for this signal. */
|
||
switch (signo)
|
||
{
|
||
case 0:
|
||
/* A sig_post msg with SIGNO==0 is sent to
|
||
tell us to check for pending signals. */
|
||
act = ignore;
|
||
break;
|
||
|
||
case SIGTTIN:
|
||
case SIGTTOU:
|
||
case SIGSTOP:
|
||
case SIGTSTP:
|
||
act = stop;
|
||
break;
|
||
|
||
case SIGCONT:
|
||
case SIGIO:
|
||
case SIGURG:
|
||
case SIGCHLD:
|
||
case SIGWINCH:
|
||
act = ignore;
|
||
break;
|
||
|
||
case SIGQUIT:
|
||
case SIGILL:
|
||
case SIGTRAP:
|
||
case SIGIOT:
|
||
case SIGEMT:
|
||
case SIGFPE:
|
||
case SIGBUS:
|
||
case SIGSEGV:
|
||
case SIGSYS:
|
||
act = core;
|
||
break;
|
||
|
||
case SIGINFO:
|
||
if (_hurd_pgrp == _hurd_pid)
|
||
{
|
||
/* We are the process group leader. Since there is no
|
||
user-specified handler for SIGINFO, we use a default one
|
||
which prints something interesting. We use the normal
|
||
handler mechanism instead of just doing it here to avoid
|
||
the signal thread faulting or blocking in this
|
||
potentially hairy operation. */
|
||
act = handle;
|
||
handler = _hurd_siginfo_handler;
|
||
}
|
||
else
|
||
act = ignore;
|
||
break;
|
||
|
||
default:
|
||
act = term;
|
||
break;
|
||
}
|
||
else if (handler == SIG_IGN)
|
||
act = ignore;
|
||
else
|
||
act = handle;
|
||
|
||
if (__sigmask (signo) & STOPSIGS)
|
||
/* Stop signals clear a pending SIGCONT even if they
|
||
are handled or ignored (but not if preempted). */
|
||
ss->pending &= ~sigmask (SIGCONT);
|
||
else
|
||
{
|
||
if (signo == SIGCONT)
|
||
/* Even if handled or ignored (but not preempted), SIGCONT clears
|
||
stop signals and resumes the process. */
|
||
ss->pending &= ~STOPSIGS;
|
||
|
||
if (_hurd_stopped && act != stop && (untraced || signo == SIGCONT))
|
||
resume ();
|
||
}
|
||
}
|
||
|
||
if (_hurd_orphaned && act == stop &&
|
||
(__sigmask (signo) & (__sigmask (SIGTTIN) | __sigmask (SIGTTOU) |
|
||
__sigmask (SIGTSTP))))
|
||
{
|
||
/* If we would ordinarily stop for a job control signal, but we are
|
||
orphaned so noone would ever notice and continue us again, we just
|
||
quietly die, alone and in the dark. */
|
||
detail->code = signo;
|
||
signo = SIGKILL;
|
||
act = term;
|
||
}
|
||
|
||
/* Handle receipt of a blocked signal, or any signal while stopped. */
|
||
if (act != ignore && /* Signals ignored now are forgotten now. */
|
||
__sigismember (&ss->blocked, signo) ||
|
||
(signo != SIGKILL && _hurd_stopped))
|
||
{
|
||
mark_pending ();
|
||
act = ignore;
|
||
}
|
||
|
||
/* Perform the chosen action for the signal. */
|
||
switch (act)
|
||
{
|
||
case stop:
|
||
if (_hurd_stopped)
|
||
{
|
||
/* We are already stopped, but receiving an untraced stop
|
||
signal. Instead of resuming and suspending again, just
|
||
notify the proc server of the new stop signal. */
|
||
error_t err = __USEPORT (PROC, __proc_mark_stop
|
||
(port, signo, detail->code));
|
||
assert_perror (err);
|
||
}
|
||
else
|
||
/* Suspend the process. */
|
||
suspend ();
|
||
break;
|
||
|
||
case ignore:
|
||
/* Nobody cares about this signal. If there was a call to resume
|
||
above in SIGCONT processing and we've left a thread suspended,
|
||
now's the time to set it going. */
|
||
if (ss_suspended)
|
||
{
|
||
err = __thread_resume (ss->thread);
|
||
assert_perror (err);
|
||
ss_suspended = 0;
|
||
}
|
||
break;
|
||
|
||
sigbomb:
|
||
/* We got a fault setting up the stack frame for the handler.
|
||
Nothing to do but die; BSD gets SIGILL in this case. */
|
||
detail->code = signo; /* XXX ? */
|
||
signo = SIGILL;
|
||
act = core;
|
||
/* FALLTHROUGH */
|
||
|
||
case term: /* Time to die. */
|
||
case core: /* And leave a rotting corpse. */
|
||
/* Have the proc server stop all other threads in our task. */
|
||
err = __USEPORT (PROC, __proc_dostop (port, _hurd_msgport_thread));
|
||
assert_perror (err);
|
||
/* No more user instructions will be executed.
|
||
The signal can now be considered delivered. */
|
||
reply ();
|
||
/* Abort all server operations now in progress. */
|
||
abort_all_rpcs (signo, &thread_state, 0);
|
||
|
||
{
|
||
int status = W_EXITCODE (0, signo);
|
||
/* Do a core dump if desired. Only set the wait status bit saying we
|
||
in fact dumped core if the operation was actually successful. */
|
||
if (act == core && write_corefile (signo, detail))
|
||
status |= WCOREFLAG;
|
||
/* Tell proc how we died and then stick the saber in the gut. */
|
||
_hurd_exit (status);
|
||
/* NOTREACHED */
|
||
}
|
||
|
||
case handle:
|
||
/* Call a handler for this signal. */
|
||
{
|
||
struct sigcontext *scp, ocontext;
|
||
int wait_for_reply, state_changed;
|
||
|
||
/* Stop the thread and abort its pending RPC operations. */
|
||
if (! ss_suspended)
|
||
{
|
||
err = __thread_suspend (ss->thread);
|
||
assert_perror (err);
|
||
}
|
||
|
||
/* Abort the thread's kernel context, so any pending message send
|
||
or receive completes immediately or aborts. If an interruptible
|
||
RPC is in progress, abort_rpcs will do this. But we must always
|
||
do it before fetching the thread's state, because
|
||
thread_get_state is never kosher before thread_abort. */
|
||
abort_thread (ss, &thread_state, NULL);
|
||
|
||
if (ss->context)
|
||
{
|
||
/* We have a previous sigcontext that sigreturn was about
|
||
to restore when another signal arrived. */
|
||
|
||
mach_port_t *loc;
|
||
|
||
if (_hurdsig_catch_memory_fault (ss->context))
|
||
{
|
||
/* We faulted reading the thread's stack. Forget that
|
||
context and pretend it wasn't there. It almost
|
||
certainly crash if this handler returns, but that's it's
|
||
problem. */
|
||
ss->context = NULL;
|
||
}
|
||
else
|
||
{
|
||
/* Copy the context from the thread's stack before
|
||
we start diddling the stack to set up the handler. */
|
||
ocontext = *ss->context;
|
||
ss->context = &ocontext;
|
||
}
|
||
_hurdsig_end_catch_fault ();
|
||
|
||
if (! machine_get_basic_state (ss->thread, &thread_state))
|
||
goto sigbomb;
|
||
loc = interrupted_reply_port_location (&thread_state, 1);
|
||
if (loc && *loc != MACH_PORT_NULL)
|
||
/* This is the reply port for the context which called
|
||
sigreturn. Since we are abandoning that context entirely
|
||
and restoring SS->context instead, destroy this port. */
|
||
__mach_port_destroy (__mach_task_self (), *loc);
|
||
|
||
/* The thread was in sigreturn, not in any interruptible RPC. */
|
||
wait_for_reply = 0;
|
||
|
||
assert (! __spin_lock_locked (&ss->critical_section_lock));
|
||
}
|
||
else
|
||
{
|
||
int crit = __spin_lock_locked (&ss->critical_section_lock);
|
||
|
||
wait_for_reply
|
||
= (_hurdsig_abort_rpcs (ss,
|
||
/* In a critical section, any RPC
|
||
should be cancelled instead of
|
||
restarted, regardless of
|
||
SA_RESTART, so the entire
|
||
"atomic" operation can be aborted
|
||
as a unit. */
|
||
crit ? 0 : signo, 1,
|
||
&thread_state, &state_changed,
|
||
&reply)
|
||
!= MACH_PORT_NULL);
|
||
|
||
if (crit)
|
||
{
|
||
/* The thread is in a critical section. Mark the signal as
|
||
pending. When it finishes the critical section, it will
|
||
check for pending signals. */
|
||
mark_pending ();
|
||
if (state_changed)
|
||
/* Some cases of interrupting an RPC must change the
|
||
thread state to back out the call. Normally this
|
||
change is rolled into the warping to the handler and
|
||
sigreturn, but we are not running the handler now
|
||
because the thread is in a critical section. Instead,
|
||
mutate the thread right away for the RPC interruption
|
||
and resume it; the RPC will return early so the
|
||
critical section can end soon. */
|
||
__thread_set_state (ss->thread, MACHINE_THREAD_STATE_FLAVOR,
|
||
(natural_t *) &thread_state.basic,
|
||
MACHINE_THREAD_STATE_COUNT);
|
||
/* */
|
||
ss->intr_port = MACH_PORT_NULL;
|
||
__thread_resume (ss->thread);
|
||
break;
|
||
}
|
||
}
|
||
|
||
/* Call the machine-dependent function to set the thread up
|
||
to run the signal handler, and preserve its old context. */
|
||
scp = _hurd_setup_sighandler (ss, handler, signo, detail,
|
||
wait_for_reply, &thread_state);
|
||
if (scp == NULL)
|
||
goto sigbomb;
|
||
|
||
/* Set the machine-independent parts of the signal context. */
|
||
|
||
{
|
||
/* Fetch the thread variable for the MiG reply port,
|
||
and set it to MACH_PORT_NULL. */
|
||
mach_port_t *loc = interrupted_reply_port_location (&thread_state,
|
||
1);
|
||
if (loc)
|
||
{
|
||
scp->sc_reply_port = *loc;
|
||
*loc = MACH_PORT_NULL;
|
||
}
|
||
else
|
||
scp->sc_reply_port = MACH_PORT_NULL;
|
||
|
||
/* Save the intr_port in use by the interrupted code,
|
||
and clear the cell before running the trampoline. */
|
||
scp->sc_intr_port = ss->intr_port;
|
||
ss->intr_port = MACH_PORT_NULL;
|
||
|
||
if (ss->context)
|
||
{
|
||
/* After the handler runs we will restore to the state in
|
||
SS->context, not the state of the thread now. So restore
|
||
that context's reply port and intr port. */
|
||
|
||
scp->sc_reply_port = ss->context->sc_reply_port;
|
||
scp->sc_intr_port = ss->context->sc_intr_port;
|
||
|
||
ss->context = NULL;
|
||
}
|
||
}
|
||
|
||
/* Backdoor extra argument to signal handler. */
|
||
scp->sc_error = detail->error;
|
||
|
||
/* Block SIGNO and requested signals while running the handler. */
|
||
scp->sc_mask = ss->blocked;
|
||
ss->blocked |= __sigmask (signo) | ss->actions[signo].sa_mask;
|
||
|
||
/* Start the thread running the handler (or possibly waiting for an
|
||
RPC reply before running the handler). */
|
||
err = __thread_set_state (ss->thread, MACHINE_THREAD_STATE_FLAVOR,
|
||
(natural_t *) &thread_state.basic,
|
||
MACHINE_THREAD_STATE_COUNT);
|
||
assert_perror (err);
|
||
err = __thread_resume (ss->thread);
|
||
assert_perror (err);
|
||
thread_state.set = 0; /* Everything we know is now wrong. */
|
||
break;
|
||
}
|
||
}
|
||
|
||
/* The signal has either been ignored or is now being handled. We can
|
||
consider it delivered and reply to the killer. */
|
||
reply ();
|
||
|
||
/* We get here unless the signal was fatal. We still hold SS->lock.
|
||
Check for pending signals, and loop to post them. */
|
||
{
|
||
/* Return nonzero if SS has any signals pending we should worry about.
|
||
We don't worry about any pending signals if we are stopped, nor if
|
||
SS is in a critical section. We are guaranteed to get a sig_post
|
||
message before any of them become deliverable: either the SIGCONT
|
||
signal, or a sig_post with SIGNO==0 as an explicit poll when the
|
||
thread finishes its critical section. */
|
||
inline int signals_pending (void)
|
||
{
|
||
if (_hurd_stopped || __spin_lock_locked (&ss->critical_section_lock))
|
||
return 0;
|
||
return pending = ss->pending & ~ss->blocked;
|
||
}
|
||
|
||
check_pending_signals:
|
||
untraced = 0;
|
||
|
||
if (signals_pending ())
|
||
{
|
||
for (signo = 1; signo < NSIG; ++signo)
|
||
if (__sigismember (&pending, signo))
|
||
{
|
||
deliver_pending:
|
||
__sigdelset (&ss->pending, signo);
|
||
*detail = ss->pending_data[signo];
|
||
__spin_unlock (&ss->lock);
|
||
goto post_signal;
|
||
}
|
||
}
|
||
|
||
/* No pending signals left undelivered for this thread.
|
||
If we were sent signal 0, we need to check for pending
|
||
signals for all threads. */
|
||
if (signo == 0)
|
||
{
|
||
__spin_unlock (&ss->lock);
|
||
__mutex_lock (&_hurd_siglock);
|
||
for (ss = _hurd_sigstates; ss != NULL; ss = ss->next)
|
||
{
|
||
__spin_lock (&ss->lock);
|
||
for (signo = 1; signo < NSIG; ++signo)
|
||
if (__sigismember (&ss->pending, signo)
|
||
&& (!__sigismember (&ss->blocked, signo)
|
||
/* We "deliver" immediately pending blocked signals whose
|
||
action might be to ignore, so that if ignored they are
|
||
dropped right away. */
|
||
|| ss->actions[signo].sa_handler == SIG_IGN
|
||
|| ss->actions[signo].sa_handler == SIG_DFL))
|
||
{
|
||
mutex_unlock (&_hurd_siglock);
|
||
goto deliver_pending;
|
||
}
|
||
__spin_unlock (&ss->lock);
|
||
}
|
||
__mutex_unlock (&_hurd_siglock);
|
||
}
|
||
else
|
||
{
|
||
/* No more signals pending; SS->lock is still locked.
|
||
Wake up any sigsuspend call that is blocking SS->thread. */
|
||
if (ss->suspended != MACH_PORT_NULL)
|
||
{
|
||
/* There is a sigsuspend waiting. Tell it to wake up. */
|
||
error_t err;
|
||
mach_msg_header_t msg;
|
||
err = __mach_port_insert_right (__mach_task_self (),
|
||
ss->suspended, ss->suspended,
|
||
MACH_MSG_TYPE_MAKE_SEND);
|
||
assert_perror (err);
|
||
msg.msgh_bits = MACH_MSGH_BITS (MACH_MSG_TYPE_MOVE_SEND, 0);
|
||
msg.msgh_remote_port = ss->suspended;
|
||
msg.msgh_local_port = MACH_PORT_NULL;
|
||
/* These values do not matter. */
|
||
msg.msgh_id = 8675309; /* Jenny, Jenny. */
|
||
msg.msgh_seqno = 17; /* Random. */
|
||
ss->suspended = MACH_PORT_NULL;
|
||
err = __mach_msg (&msg, MACH_SEND_MSG, sizeof msg, 0,
|
||
MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE,
|
||
MACH_PORT_NULL);
|
||
assert_perror (err);
|
||
}
|
||
__spin_unlock (&ss->lock);
|
||
}
|
||
}
|
||
|
||
/* All pending signals delivered to all threads.
|
||
Now we can send the reply message even for signal 0. */
|
||
reply ();
|
||
}
|
||
|
||
/* Decide whether REFPORT enables the sender to send us a SIGNO signal.
|
||
Returns zero if so, otherwise the error code to return to the sender. */
|
||
|
||
static error_t
|
||
signal_allowed (int signo, mach_port_t refport)
|
||
{
|
||
if (signo < 0 || signo >= NSIG)
|
||
return EINVAL;
|
||
|
||
if (refport == __mach_task_self ())
|
||
/* Can send any signal. */
|
||
goto win;
|
||
|
||
/* Avoid needing to check for this below. */
|
||
if (refport == MACH_PORT_NULL)
|
||
return EPERM;
|
||
|
||
switch (signo)
|
||
{
|
||
case SIGINT:
|
||
case SIGQUIT:
|
||
case SIGTSTP:
|
||
case SIGHUP:
|
||
case SIGINFO:
|
||
case SIGTTIN:
|
||
case SIGTTOU:
|
||
case SIGWINCH:
|
||
/* Job control signals can be sent by the controlling terminal. */
|
||
if (__USEPORT (CTTYID, port == refport))
|
||
goto win;
|
||
break;
|
||
|
||
case SIGCONT:
|
||
{
|
||
/* A continue signal can be sent by anyone in the session. */
|
||
mach_port_t sessport;
|
||
if (! __USEPORT (PROC, __proc_getsidport (port, &sessport)))
|
||
{
|
||
__mach_port_deallocate (__mach_task_self (), sessport);
|
||
if (refport == sessport)
|
||
goto win;
|
||
}
|
||
}
|
||
break;
|
||
|
||
case SIGIO:
|
||
case SIGURG:
|
||
{
|
||
/* Any io object a file descriptor refers to might send us
|
||
one of these signals using its async ID port for REFPORT.
|
||
|
||
This is pretty wide open; it is not unlikely that some random
|
||
process can at least open for reading something we have open,
|
||
get its async ID port, and send us a spurious SIGIO or SIGURG
|
||
signal. But BSD is actually wider open than that!--you can set
|
||
the owner of an io object to any process or process group
|
||
whatsoever and send them gratuitous signals.
|
||
|
||
Someday we could implement some reasonable scheme for
|
||
authorizing SIGIO and SIGURG signals properly. */
|
||
|
||
int d;
|
||
int lucky = 0; /* True if we find a match for REFPORT. */
|
||
__mutex_lock (&_hurd_dtable_lock);
|
||
for (d = 0; !lucky && (unsigned) d < (unsigned) _hurd_dtablesize; ++d)
|
||
{
|
||
struct hurd_userlink ulink;
|
||
io_t port;
|
||
mach_port_t asyncid;
|
||
if (_hurd_dtable[d] == NULL)
|
||
continue;
|
||
port = _hurd_port_get (&_hurd_dtable[d]->port, &ulink);
|
||
if (! __io_get_icky_async_id (port, &asyncid))
|
||
{
|
||
if (refport == asyncid)
|
||
/* Break out of the loop on the next iteration. */
|
||
lucky = 1;
|
||
__mach_port_deallocate (__mach_task_self (), asyncid);
|
||
}
|
||
_hurd_port_free (&_hurd_dtable[d]->port, &ulink, port);
|
||
}
|
||
/* If we found a lucky winner, we've set D to -1 in the loop. */
|
||
if (lucky)
|
||
goto win;
|
||
}
|
||
}
|
||
|
||
/* If this signal is legit, we have done `goto win' by now.
|
||
When we return the error, mig deallocates REFPORT. */
|
||
return EPERM;
|
||
|
||
win:
|
||
/* Deallocate the REFPORT send right; we are done with it. */
|
||
__mach_port_deallocate (__mach_task_self (), refport);
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Implement the sig_post RPC from <hurd/msg.defs>;
|
||
sent when someone wants us to get a signal. */
|
||
kern_return_t
|
||
_S_msg_sig_post (mach_port_t me,
|
||
mach_port_t reply_port, mach_msg_type_name_t reply_port_type,
|
||
int signo, natural_t sigcode,
|
||
mach_port_t refport)
|
||
{
|
||
error_t err;
|
||
struct hurd_signal_detail d;
|
||
|
||
if (err = signal_allowed (signo, refport))
|
||
return err;
|
||
|
||
d.code = sigcode;
|
||
d.exc = 0;
|
||
|
||
/* Post the signal to the designated signal-receiving thread. This will
|
||
reply when the signal can be considered delivered. */
|
||
_hurd_internal_post_signal (_hurd_thread_sigstate (_hurd_sigthread),
|
||
signo, &d, reply_port, reply_port_type,
|
||
0); /* Stop if traced. */
|
||
|
||
return MIG_NO_REPLY; /* Already replied. */
|
||
}
|
||
|
||
/* Implement the sig_post_untraced RPC from <hurd/msg.defs>;
|
||
sent when the debugger wants us to really get a signal
|
||
even if we are traced. */
|
||
kern_return_t
|
||
_S_msg_sig_post_untraced (mach_port_t me,
|
||
mach_port_t reply_port,
|
||
mach_msg_type_name_t reply_port_type,
|
||
int signo, natural_t sigcode,
|
||
mach_port_t refport)
|
||
{
|
||
error_t err;
|
||
struct hurd_signal_detail d;
|
||
|
||
if (err = signal_allowed (signo, refport))
|
||
return err;
|
||
|
||
d.code = sigcode;
|
||
d.exc = 0;
|
||
|
||
/* Post the signal to the designated signal-receiving thread. This will
|
||
reply when the signal can be considered delivered. */
|
||
_hurd_internal_post_signal (_hurd_thread_sigstate (_hurd_sigthread),
|
||
signo, &d, reply_port, reply_port_type,
|
||
1); /* Untraced flag. */
|
||
|
||
return MIG_NO_REPLY; /* Already replied. */
|
||
}
|
||
|
||
extern void __mig_init (void *);
|
||
|
||
#include <mach/task_special_ports.h>
|
||
|
||
/* Initialize the message port and _hurd_sigthread and start the signal
|
||
thread. */
|
||
|
||
void
|
||
_hurdsig_init (const int *intarray, size_t intarraysize)
|
||
{
|
||
error_t err;
|
||
vm_size_t stacksize;
|
||
struct hurd_sigstate *ss;
|
||
|
||
__mutex_init (&_hurd_siglock);
|
||
|
||
err = __mach_port_allocate (__mach_task_self (),
|
||
MACH_PORT_RIGHT_RECEIVE,
|
||
&_hurd_msgport);
|
||
assert_perror (err);
|
||
|
||
/* Make a send right to the signal port. */
|
||
err = __mach_port_insert_right (__mach_task_self (),
|
||
_hurd_msgport,
|
||
_hurd_msgport,
|
||
MACH_MSG_TYPE_MAKE_SEND);
|
||
assert_perror (err);
|
||
|
||
/* Initialize the main thread's signal state. */
|
||
ss = _hurd_self_sigstate ();
|
||
|
||
/* Copy inherited values from our parent (or pre-exec process state)
|
||
into the signal settings of the main thread. */
|
||
if (intarraysize > INIT_SIGMASK)
|
||
ss->blocked = intarray[INIT_SIGMASK];
|
||
if (intarraysize > INIT_SIGPENDING)
|
||
ss->blocked = intarray[INIT_SIGPENDING];
|
||
if (intarraysize > INIT_SIGIGN && intarray[INIT_SIGIGN] != 0)
|
||
{
|
||
int signo;
|
||
for (signo = 1; signo < NSIG; ++signo)
|
||
if (intarray[INIT_SIGIGN] & __sigmask(signo))
|
||
ss->actions[signo].sa_handler = SIG_IGN;
|
||
}
|
||
|
||
/* Set the default thread to receive task-global signals
|
||
to this one, the main (first) user thread. */
|
||
_hurd_sigthread = ss->thread;
|
||
|
||
/* Start the signal thread listening on the message port. */
|
||
|
||
err = __thread_create (__mach_task_self (), &_hurd_msgport_thread);
|
||
assert_perror (err);
|
||
|
||
stacksize = __vm_page_size * 8; /* Small stack for signal thread. */
|
||
err = __mach_setup_thread (__mach_task_self (), _hurd_msgport_thread,
|
||
_hurd_msgport_receive,
|
||
(vm_address_t *) &__hurd_sigthread_stack_base,
|
||
&stacksize);
|
||
assert_perror (err);
|
||
|
||
__hurd_sigthread_stack_end = __hurd_sigthread_stack_base + stacksize;
|
||
__hurd_sigthread_variables =
|
||
malloc (__hurd_threadvar_max * sizeof (unsigned long int));
|
||
if (__hurd_sigthread_variables == NULL)
|
||
__libc_fatal ("hurd: Can't allocate thread variables for signal thread\n");
|
||
|
||
/* Reinitialize the MiG support routines so they will use a per-thread
|
||
variable for the cached reply port. */
|
||
__mig_init ((void *) __hurd_sigthread_stack_base);
|
||
|
||
err = __thread_resume (_hurd_msgport_thread);
|
||
assert_perror (err);
|
||
|
||
/* Receive exceptions on the signal port. */
|
||
__task_set_special_port (__mach_task_self (),
|
||
TASK_EXCEPTION_PORT, _hurd_msgport);
|
||
|
||
/* Sanity check. Any pending, unblocked signals should have been
|
||
taken by our predecessor incarnation (i.e. parent or pre-exec state)
|
||
before packing up our init ints. This assert is last (not above)
|
||
so that signal handling is all set up to handle the abort. */
|
||
assert ((ss->pending &~ ss->blocked) == 0);
|
||
}
|
||
/* XXXX */
|
||
/* Reauthenticate with the proc server. */
|
||
|
||
static void
|
||
reauth_proc (mach_port_t new)
|
||
{
|
||
mach_port_t ref, ignore;
|
||
|
||
ref = __mach_reply_port ();
|
||
if (! HURD_PORT_USE (&_hurd_ports[INIT_PORT_PROC],
|
||
__proc_reauthenticate (port, ref,
|
||
MACH_MSG_TYPE_MAKE_SEND) ||
|
||
__auth_user_authenticate (new, ref,
|
||
MACH_MSG_TYPE_MAKE_SEND,
|
||
&ignore))
|
||
&& ignore != MACH_PORT_NULL)
|
||
__mach_port_deallocate (__mach_task_self (), ignore);
|
||
__mach_port_destroy (__mach_task_self (), ref);
|
||
|
||
/* Set the owner of the process here too. */
|
||
mutex_lock (&_hurd_id.lock);
|
||
if (!_hurd_check_ids ())
|
||
HURD_PORT_USE (&_hurd_ports[INIT_PORT_PROC],
|
||
__proc_setowner (port,
|
||
(_hurd_id.gen.nuids
|
||
? _hurd_id.gen.uids[0] : 0),
|
||
!_hurd_id.gen.nuids));
|
||
mutex_unlock (&_hurd_id.lock);
|
||
|
||
(void) &reauth_proc; /* Silence compiler warning. */
|
||
}
|
||
text_set_element (_hurd_reauth_hook, reauth_proc);
|
||
|
||
/* Like `getenv', but safe for the signal thread to run.
|
||
If the environment is trashed, this will just return NULL. */
|
||
|
||
const char *
|
||
_hurdsig_getenv (const char *variable)
|
||
{
|
||
if (_hurdsig_catch_memory_fault (__environ))
|
||
/* We bombed in getenv. */
|
||
return NULL;
|
||
else
|
||
{
|
||
const size_t len = strlen (variable);
|
||
char *value = NULL;
|
||
char *volatile *ep = __environ;
|
||
while (*ep)
|
||
{
|
||
const char *p = *ep;
|
||
_hurdsig_fault_preemptor.first = (long int) p;
|
||
_hurdsig_fault_preemptor.last = VM_MAX_ADDRESS;
|
||
if (! strncmp (p, variable, len) && p[len] == '=')
|
||
{
|
||
char *value;
|
||
size_t valuelen;
|
||
p += len + 1;
|
||
valuelen = strlen (p);
|
||
_hurdsig_fault_preemptor.last = (long int) (p + valuelen);
|
||
value = malloc (++valuelen);
|
||
if (value)
|
||
memcpy (value, p, valuelen);
|
||
break;
|
||
}
|
||
_hurdsig_fault_preemptor.first = (long int) ++ep;
|
||
_hurdsig_fault_preemptor.last = (long int) (ep + 1);
|
||
}
|
||
_hurdsig_end_catch_fault ();
|
||
return value;
|
||
}
|
||
}
|