Attachment 219487 Details for Bug 250954 – print the list of threads on each stop

print the list of threads on each stop

thread-dbreg-test-pt2.c (text/plain), 3.60 KB, created by Konstantin Belousov on 2020-11-09 11:50:07 UTC

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Creator: Konstantin Belousov

Created: 2020-11-09 11:50:07 UTC

Size: 3.60 KB

patch

obsolete

>/* $Id: thread-dbreg-test-pt2.c,v 1.7 2020/11/09 11:42:26 kostik Exp kostik $ */
>
>#include <sys/types.h>
>#include <sys/ptrace.h>
>#include <sys/wait.h>
>#include <machine/reg.h>
>#include <assert.h>
>#include <err.h>
>#include <pthread.h>
>#include <signal.h>
>#include <stdint.h>
>#include <stdio.h>
>#include <unistd.h>
>
>volatile int g_val;
>volatile int g_val2;
>
>static void *
>thread_func(void* foo __unused) {
>	return (NULL);
>}
>
>static void
>waitdbg(pid_t pid, int sig)
>{
>	pid_t waited;
>	int nthr, ret;
>
>	waited = waitpid(pid, &ret, 0);
>	printf("wait: pid=%d, waited=%d, ret=%x\n", pid, waited, ret);
>	assert(waited == pid);
>	if (sig < 0) {
>		assert(WIFEXITED(ret));
>		return;
>	}
>
>	assert(WSTOPSIG(ret) == sig);
>
>	nthr = ptrace(PT_GETNUMLWPS, pid, NULL, 0);
>	if (nthr == -1)
>		err(1, "PT_GETNUMLWPS");
>	lwpid_t ids[nthr];
>	ret = ptrace(PT_GETLWPLIST, pid, (caddr_t)&ids, nthr);
>	if (ret == -1)
>		err(1, "PT_GETLWPLIST");
>	printf("threads:");
>	for (int i = 0; i < nthr; i++)
>		printf(" %d", ids[i]);
>	printf("\n");
>}
>
>int
>main(void)
>{
>	int ret;
>	int pid = fork();
>	assert(pid != -1);
>	if (pid == 0) {
>		pthread_t t2;
>
>		ret = ptrace(PT_TRACE_ME, 0, NULL, 0);
>		assert(ret != -1);
>		// 2. wait for parent to set dbregs
>		raise(SIGSTOP);
>
>		// 4. start new thread and stop immediately afterwards
>		ret = pthread_create(&t2, NULL, thread_func, NULL);
>		assert(ret == 0);
>		raise(SIGSTOP);
>		printf("thread started\n");
>
>		ret = pthread_join(t2, NULL);
>		assert(ret == 0);
>		printf("thread joined\n");
>		_exit(0);
>	}
>
>	// 1. wait for the child to start
>	waitdbg(pid, SIGSTOP);
>
>	struct ptrace_lwpinfo info;
>	ret = ptrace(PT_LWPINFO, pid, (caddr_t)&info, sizeof(info));
>	assert(ret != -1);
>	assert(info.pl_flags == PL_FLAG_SI);
>	printf("tid = %d, SIGSTOP\n", info.pl_lwpid);
>
>	// 3. set event mask & dbregs
>	int ev = PTRACE_LWP;
>	ret = ptrace(PT_SET_EVENT_MASK, pid, (caddr_t)&ev, sizeof(ev));
>	assert(ret != -1);
>
>	struct dbreg db;
>	ret = ptrace(PT_GETDBREGS, info.pl_lwpid, (caddr_t)&db, 0);
>	assert(ret != -1);
>
>	db.dr[0] = (uintptr_t)&g_val;
>	db.dr[7] = 0x303;
>	ret = ptrace(PT_SETDBREGS, info.pl_lwpid, (caddr_t)&db, 0);
>	assert(ret != -1);
>	printf("set DR0=%p (&g_val) on tid=%d\n", (void*)db.dr[0], info.pl_lwpid);
>
>	ret = ptrace(PT_CONTINUE, pid, (caddr_t)1, 0);
>	assert(ret != -1);
>
>	// 5. we should get SIGSTOP first, change dbregs
>	waitdbg(pid, SIGSTOP);
>
>	ret = ptrace(PT_LWPINFO, pid, (caddr_t)&info, sizeof(info));
>	assert(ret != -1);
>	assert(info.pl_flags == PL_FLAG_SI);
>	printf("tid = %d, SIGSTOP\n", info.pl_lwpid);
>
>	ret = ptrace(PT_GETDBREGS, info.pl_lwpid, (caddr_t)&db, 0);
>	assert(ret != -1);
>
>	db.dr[0] = (uintptr_t)&g_val2;
>	db.dr[7] = 0x303;
>	ret = ptrace(PT_SETDBREGS, info.pl_lwpid, (caddr_t)&db, 0);
>	assert(ret != -1);
>	printf("set DR0=%p (&g_val2) on tid=%d\n", (void*)db.dr[0], info.pl_lwpid);
>
>	ret = ptrace(PT_CONTINUE, pid, (caddr_t)1, 0);
>	assert(ret != -1);
>
>	// 6. now we should get the new thread event
>	waitdbg(pid, SIGTRAP);
>
>	ret = ptrace(PT_LWPINFO, pid, (caddr_t)&info, sizeof(info));
>	assert(ret != -1);
>	assert(info.pl_flags & PL_FLAG_BORN);
>	printf("tid = %d, SIGTRAP w/ PL_FLAG_BORN\n", info.pl_lwpid);
>
>	ret = ptrace(PT_GETDBREGS, info.pl_lwpid, (caddr_t)&db, 0);
>	assert(ret != -1);
>	printf("dr0=%p, g_val=%p, g_val2=%p\n", (void*)db.dr[0], &g_val, &g_val2);
>
>	ret = ptrace(PT_CONTINUE, pid, (caddr_t)1, 0);
>	assert(ret != -1);
>
>	// thread exited
>	waitdbg(pid, SIGTRAP);
>
>	ret = ptrace(PT_LWPINFO, pid, (caddr_t)&info, sizeof(info));
>	assert(ret != -1);
>	assert(info.pl_flags & PL_FLAG_EXITED);
>	printf("tid = %d, SIGTRAP w/ PL_FLAG_EXITED\n", info.pl_lwpid);
>
>	ret = ptrace(PT_CONTINUE, pid, (caddr_t)1, 0);
>	assert(ret != -1);
>
>	waitdbg(pid, -1);
>}

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Attachments on bug 250954: 219458 | 219480 | 219487