mirror of
https://git.FreeBSD.org/src.git
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5695afded4
Approved by: kib (mentor) MFC after: 2 weeks
242 lines
5.8 KiB
C
242 lines
5.8 KiB
C
/*-
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* Copyright 1997 Sean Eric Fagan
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Sean Eric Fagan
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* 4. Neither the name of the author may be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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/*
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* Various setup functions for truss. Not the cleanest-written code,
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* I'm afraid.
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*/
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#include <sys/param.h>
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#include <sys/types.h>
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#include <sys/ptrace.h>
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#include <sys/wait.h>
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#include <unistd.h>
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#include <machine/reg.h>
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#include "truss.h"
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#include "extern.h"
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static sig_atomic_t detaching;
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/*
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* setup_and_wait() is called to start a process. All it really does
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* is fork(), set itself up to stop on exec or exit, and then exec
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* the given command. At that point, the child process stops, and
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* the parent can wake up and deal with it.
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*/
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int
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setup_and_wait(char *command[])
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{
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pid_t pid;
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pid = vfork();
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if (pid == -1)
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err(1, "fork failed");
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if (pid == 0) { /* Child */
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ptrace(PT_TRACE_ME, 0, 0, 0);
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execvp(command[0], command);
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err(1, "execvp %s", command[0]);
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}
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/* Only in the parent here */
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if (waitpid(pid, NULL, 0) < 0)
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err(1, "unexpect stop in waitpid");
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return (pid);
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}
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/*
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* start_tracing picks up where setup_and_wait() dropped off -- namely,
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* it sets the event mask for the given process id. Called for both
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* monitoring an existing process and when we create our own.
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*/
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int
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start_tracing(pid_t pid)
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{
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int ret, retry;
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retry = 10;
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do {
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ret = ptrace(PT_ATTACH, pid, NULL, 0);
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usleep(200);
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} while (ret && retry-- > 0);
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if (ret)
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err(1, "can not attach to target process");
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if (waitpid(pid, NULL, 0) < 0)
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err(1, "Unexpect stop in waitpid");
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return (0);
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}
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/*
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* Restore a process back to it's pre-truss state.
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* Called for SIGINT, SIGTERM, SIGQUIT. This only
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* applies if truss was told to monitor an already-existing
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* process.
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*/
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void
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restore_proc(int signo __unused)
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{
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detaching = 1;
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}
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static int
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detach_proc(pid_t pid)
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{
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int waitval;
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/* stop the child so that we can detach */
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kill(pid, SIGSTOP);
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if (waitpid(pid, &waitval, 0) < 0)
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err(1, "Unexpected stop in waitpid");
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if (ptrace(PT_DETACH, pid, (caddr_t)1, 0) < 0)
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err(1, "Can not detach the process");
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kill(pid, SIGCONT);
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return (waitval);
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}
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/*
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* Change curthread member based on lwpid.
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* If it is a new thread, create a threadinfo structure
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*/
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static void
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find_thread(struct trussinfo *info, lwpid_t lwpid)
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{
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struct threadinfo *np;
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info->curthread = NULL;
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SLIST_FOREACH(np, &info->threadlist, entries) {
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if (np->tid == lwpid) {
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info->curthread = np;
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return;
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}
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}
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np = (struct threadinfo *)calloc(1, sizeof(struct threadinfo));
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if (np == NULL)
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err(1, "calloc() failed");
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np->tid = lwpid;
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SLIST_INSERT_HEAD(&info->threadlist, np, entries);
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info->curthread = np;
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}
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/*
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* Start the traced process and wait until it stoped.
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* Fill trussinfo structure.
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* When this even returns, the traced process is in stop state.
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*/
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void
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waitevent(struct trussinfo *info)
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{
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struct ptrace_lwpinfo lwpinfo;
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static int pending_signal = 0;
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int waitval;
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ptrace(PT_SYSCALL, info->pid, (caddr_t)1, pending_signal);
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pending_signal = 0;
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detach:
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if (detaching) {
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waitval = detach_proc(info->pid);
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info->pr_why = S_DETACHED;
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info->pr_data = WEXITSTATUS(waitval);
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return;
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}
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if (waitpid(info->pid, &waitval, 0) == -1) {
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if (errno == EINTR)
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goto detach;
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err(1, "Unexpected stop in waitpid");
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}
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if (WIFCONTINUED(waitval)) {
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info->pr_why = S_NONE;
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return;
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}
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if (WIFEXITED(waitval)) {
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info->pr_why = S_EXIT;
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info->pr_data = WEXITSTATUS(waitval);
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return;
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}
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if (WIFSTOPPED(waitval)) {
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ptrace(PT_LWPINFO, info->pid, (caddr_t)&lwpinfo,
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sizeof(lwpinfo));
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find_thread(info, lwpinfo.pl_lwpid);
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switch (WSTOPSIG(waitval)) {
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case SIGTRAP:
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if (lwpinfo.pl_flags & PL_FLAG_SCE) {
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info->pr_why = S_SCE;
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info->curthread->in_syscall = 1;
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break;
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} else if (lwpinfo.pl_flags & PL_FLAG_SCX) {
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info->pr_why = S_SCX;
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info->curthread->in_syscall = 0;
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break;
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} else {
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errx(1,
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"pl_flags %x contains neither PL_FLAG_SCE nor PL_FLAG_SCX",
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lwpinfo.pl_flags);
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}
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default:
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info->pr_why = S_SIG;
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info->pr_data = WSTOPSIG(waitval);
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pending_signal = info->pr_data;
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break;
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}
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}
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if (WIFSIGNALED(waitval)) {
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info->pr_why = S_EXIT;
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info->pr_data = 0;
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return;
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}
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}
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