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-rw-r--r--lib/sanitizer_common/sanitizer_stoptheworld_netbsd_libcdep.cpp356
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diff --git a/lib/sanitizer_common/sanitizer_stoptheworld_netbsd_libcdep.cpp b/lib/sanitizer_common/sanitizer_stoptheworld_netbsd_libcdep.cpp
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index 000000000000..5690d75097f9
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+++ b/lib/sanitizer_common/sanitizer_stoptheworld_netbsd_libcdep.cpp
@@ -0,0 +1,356 @@
+//===-- sanitizer_stoptheworld_netbsd_libcdep.cpp -------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// See sanitizer_stoptheworld.h for details.
+// This implementation was inspired by Markus Gutschke's linuxthreads.cc.
+//
+// This is a NetBSD variation of Linux stoptheworld implementation
+// See sanitizer_stoptheworld_linux_libcdep.cpp for code comments.
+//
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_platform.h"
+
+#if SANITIZER_NETBSD
+
+#include "sanitizer_stoptheworld.h"
+
+#include "sanitizer_atomic.h"
+#include "sanitizer_platform_limits_posix.h"
+
+#include <sys/types.h>
+
+#include <sys/ptrace.h>
+#include <sys/uio.h>
+#include <sys/wait.h>
+
+#include <machine/reg.h>
+
+#include <elf.h>
+#include <errno.h>
+#include <sched.h>
+#include <signal.h>
+#include <stddef.h>
+
+#define internal_sigaction_norestorer internal_sigaction
+
+#include "sanitizer_common.h"
+#include "sanitizer_flags.h"
+#include "sanitizer_libc.h"
+#include "sanitizer_linux.h"
+#include "sanitizer_mutex.h"
+#include "sanitizer_placement_new.h"
+
+namespace __sanitizer {
+
+class SuspendedThreadsListNetBSD : public SuspendedThreadsList {
+ public:
+ SuspendedThreadsListNetBSD() { thread_ids_.reserve(1024); }
+
+ tid_t GetThreadID(uptr index) const;
+ uptr ThreadCount() const;
+ bool ContainsTid(tid_t thread_id) const;
+ void Append(tid_t tid);
+
+ PtraceRegistersStatus GetRegistersAndSP(uptr index, uptr *buffer,
+ uptr *sp) const;
+ uptr RegisterCount() const;
+
+ private:
+ InternalMmapVector<tid_t> thread_ids_;
+};
+
+struct TracerThreadArgument {
+ StopTheWorldCallback callback;
+ void *callback_argument;
+ BlockingMutex mutex;
+ atomic_uintptr_t done;
+ uptr parent_pid;
+};
+
+class ThreadSuspender {
+ public:
+ explicit ThreadSuspender(pid_t pid, TracerThreadArgument *arg)
+ : arg(arg), pid_(pid) {
+ CHECK_GE(pid, 0);
+ }
+ bool SuspendAllThreads();
+ void ResumeAllThreads();
+ void KillAllThreads();
+ SuspendedThreadsListNetBSD &suspended_threads_list() {
+ return suspended_threads_list_;
+ }
+ TracerThreadArgument *arg;
+
+ private:
+ SuspendedThreadsListNetBSD suspended_threads_list_;
+ pid_t pid_;
+};
+
+void ThreadSuspender::ResumeAllThreads() {
+ int pterrno;
+ if (!internal_iserror(internal_ptrace(PT_DETACH, pid_, (void *)(uptr)1, 0),
+ &pterrno)) {
+ VReport(2, "Detached from process %d.\n", pid_);
+ } else {
+ VReport(1, "Could not detach from process %d (errno %d).\n", pid_, pterrno);
+ }
+}
+
+void ThreadSuspender::KillAllThreads() {
+ internal_ptrace(PT_KILL, pid_, nullptr, 0);
+}
+
+bool ThreadSuspender::SuspendAllThreads() {
+ int pterrno;
+ if (internal_iserror(internal_ptrace(PT_ATTACH, pid_, nullptr, 0),
+ &pterrno)) {
+ Printf("Could not attach to process %d (errno %d).\n", pid_, pterrno);
+ return false;
+ }
+
+ int status;
+ uptr waitpid_status;
+ HANDLE_EINTR(waitpid_status, internal_waitpid(pid_, &status, 0));
+
+ VReport(2, "Attached to process %d.\n", pid_);
+
+ struct ptrace_lwpinfo pl;
+ int val;
+ pl.pl_lwpid = 0;
+ while ((val = ptrace(PT_LWPINFO, pid_, (void *)&pl, sizeof(pl))) != -1 &&
+ pl.pl_lwpid != 0) {
+ suspended_threads_list_.Append(pl.pl_lwpid);
+ VReport(2, "Appended thread %d in process %d.\n", pl.pl_lwpid, pid_);
+ }
+ return true;
+}
+
+// Pointer to the ThreadSuspender instance for use in signal handler.
+static ThreadSuspender *thread_suspender_instance = nullptr;
+
+// Synchronous signals that should not be blocked.
+static const int kSyncSignals[] = {SIGABRT, SIGILL, SIGFPE, SIGSEGV,
+ SIGBUS, SIGXCPU, SIGXFSZ};
+
+static void TracerThreadDieCallback() {
+ ThreadSuspender *inst = thread_suspender_instance;
+ if (inst && stoptheworld_tracer_pid == internal_getpid()) {
+ inst->KillAllThreads();
+ thread_suspender_instance = nullptr;
+ }
+}
+
+// Signal handler to wake up suspended threads when the tracer thread dies.
+static void TracerThreadSignalHandler(int signum, __sanitizer_siginfo *siginfo,
+ void *uctx) {
+ SignalContext ctx(siginfo, uctx);
+ Printf("Tracer caught signal %d: addr=0x%zx pc=0x%zx sp=0x%zx\n", signum,
+ ctx.addr, ctx.pc, ctx.sp);
+ ThreadSuspender *inst = thread_suspender_instance;
+ if (inst) {
+ if (signum == SIGABRT)
+ inst->KillAllThreads();
+ else
+ inst->ResumeAllThreads();
+ RAW_CHECK(RemoveDieCallback(TracerThreadDieCallback));
+ thread_suspender_instance = nullptr;
+ atomic_store(&inst->arg->done, 1, memory_order_relaxed);
+ }
+ internal__exit((signum == SIGABRT) ? 1 : 2);
+}
+
+// Size of alternative stack for signal handlers in the tracer thread.
+static const int kHandlerStackSize = 8192;
+
+// This function will be run as a cloned task.
+static int TracerThread(void *argument) {
+ TracerThreadArgument *tracer_thread_argument =
+ (TracerThreadArgument *)argument;
+
+ // Check if parent is already dead.
+ if (internal_getppid() != tracer_thread_argument->parent_pid)
+ internal__exit(4);
+
+ // Wait for the parent thread to finish preparations.
+ tracer_thread_argument->mutex.Lock();
+ tracer_thread_argument->mutex.Unlock();
+
+ RAW_CHECK(AddDieCallback(TracerThreadDieCallback));
+
+ ThreadSuspender thread_suspender(internal_getppid(), tracer_thread_argument);
+ // Global pointer for the signal handler.
+ thread_suspender_instance = &thread_suspender;
+
+ // Alternate stack for signal handling.
+ InternalMmapVector<char> handler_stack_memory(kHandlerStackSize);
+ stack_t handler_stack;
+ internal_memset(&handler_stack, 0, sizeof(handler_stack));
+ handler_stack.ss_sp = handler_stack_memory.data();
+ handler_stack.ss_size = kHandlerStackSize;
+ internal_sigaltstack(&handler_stack, nullptr);
+
+ // Install our handler for synchronous signals. Other signals should be
+ // blocked by the mask we inherited from the parent thread.
+ for (uptr i = 0; i < ARRAY_SIZE(kSyncSignals); i++) {
+ __sanitizer_sigaction act;
+ internal_memset(&act, 0, sizeof(act));
+ act.sigaction = TracerThreadSignalHandler;
+ act.sa_flags = SA_ONSTACK | SA_SIGINFO;
+ internal_sigaction_norestorer(kSyncSignals[i], &act, 0);
+ }
+
+ int exit_code = 0;
+ if (!thread_suspender.SuspendAllThreads()) {
+ VReport(1, "Failed suspending threads.\n");
+ exit_code = 3;
+ } else {
+ tracer_thread_argument->callback(thread_suspender.suspended_threads_list(),
+ tracer_thread_argument->callback_argument);
+ thread_suspender.ResumeAllThreads();
+ exit_code = 0;
+ }
+ RAW_CHECK(RemoveDieCallback(TracerThreadDieCallback));
+ thread_suspender_instance = nullptr;
+ atomic_store(&tracer_thread_argument->done, 1, memory_order_relaxed);
+ return exit_code;
+}
+
+class ScopedStackSpaceWithGuard {
+ public:
+ explicit ScopedStackSpaceWithGuard(uptr stack_size) {
+ stack_size_ = stack_size;
+ guard_size_ = GetPageSizeCached();
+ // FIXME: Omitting MAP_STACK here works in current kernels but might break
+ // in the future.
+ guard_start_ =
+ (uptr)MmapOrDie(stack_size_ + guard_size_, "ScopedStackWithGuard");
+ CHECK(MprotectNoAccess((uptr)guard_start_, guard_size_));
+ }
+ ~ScopedStackSpaceWithGuard() {
+ UnmapOrDie((void *)guard_start_, stack_size_ + guard_size_);
+ }
+ void *Bottom() const {
+ return (void *)(guard_start_ + stack_size_ + guard_size_);
+ }
+
+ private:
+ uptr stack_size_;
+ uptr guard_size_;
+ uptr guard_start_;
+};
+
+static __sanitizer_sigset_t blocked_sigset;
+static __sanitizer_sigset_t old_sigset;
+
+struct ScopedSetTracerPID {
+ explicit ScopedSetTracerPID(uptr tracer_pid) {
+ stoptheworld_tracer_pid = tracer_pid;
+ stoptheworld_tracer_ppid = internal_getpid();
+ }
+ ~ScopedSetTracerPID() {
+ stoptheworld_tracer_pid = 0;
+ stoptheworld_tracer_ppid = 0;
+ }
+};
+
+void StopTheWorld(StopTheWorldCallback callback, void *argument) {
+ // Prepare the arguments for TracerThread.
+ struct TracerThreadArgument tracer_thread_argument;
+ tracer_thread_argument.callback = callback;
+ tracer_thread_argument.callback_argument = argument;
+ tracer_thread_argument.parent_pid = internal_getpid();
+ atomic_store(&tracer_thread_argument.done, 0, memory_order_relaxed);
+ const uptr kTracerStackSize = 2 * 1024 * 1024;
+ ScopedStackSpaceWithGuard tracer_stack(kTracerStackSize);
+
+ tracer_thread_argument.mutex.Lock();
+
+ internal_sigfillset(&blocked_sigset);
+ for (uptr i = 0; i < ARRAY_SIZE(kSyncSignals); i++)
+ internal_sigdelset(&blocked_sigset, kSyncSignals[i]);
+ int rv = internal_sigprocmask(SIG_BLOCK, &blocked_sigset, &old_sigset);
+ CHECK_EQ(rv, 0);
+ uptr tracer_pid = internal_clone(TracerThread, tracer_stack.Bottom(),
+ CLONE_VM | CLONE_FS | CLONE_FILES,
+ &tracer_thread_argument);
+ internal_sigprocmask(SIG_SETMASK, &old_sigset, 0);
+ int local_errno = 0;
+ if (internal_iserror(tracer_pid, &local_errno)) {
+ VReport(1, "Failed spawning a tracer thread (errno %d).\n", local_errno);
+ tracer_thread_argument.mutex.Unlock();
+ } else {
+ ScopedSetTracerPID scoped_set_tracer_pid(tracer_pid);
+
+ tracer_thread_argument.mutex.Unlock();
+
+ while (atomic_load(&tracer_thread_argument.done, memory_order_relaxed) == 0)
+ sched_yield();
+
+ for (;;) {
+ uptr waitpid_status = internal_waitpid(tracer_pid, nullptr, __WALL);
+ if (!internal_iserror(waitpid_status, &local_errno))
+ break;
+ if (local_errno == EINTR)
+ continue;
+ VReport(1, "Waiting on the tracer thread failed (errno %d).\n",
+ local_errno);
+ break;
+ }
+ }
+}
+
+tid_t SuspendedThreadsListNetBSD::GetThreadID(uptr index) const {
+ CHECK_LT(index, thread_ids_.size());
+ return thread_ids_[index];
+}
+
+uptr SuspendedThreadsListNetBSD::ThreadCount() const {
+ return thread_ids_.size();
+}
+
+bool SuspendedThreadsListNetBSD::ContainsTid(tid_t thread_id) const {
+ for (uptr i = 0; i < thread_ids_.size(); i++) {
+ if (thread_ids_[i] == thread_id)
+ return true;
+ }
+ return false;
+}
+
+void SuspendedThreadsListNetBSD::Append(tid_t tid) {
+ thread_ids_.push_back(tid);
+}
+
+PtraceRegistersStatus SuspendedThreadsListNetBSD::GetRegistersAndSP(
+ uptr index, uptr *buffer, uptr *sp) const {
+ lwpid_t tid = GetThreadID(index);
+ pid_t ppid = internal_getppid();
+ struct reg regs;
+ int pterrno;
+ bool isErr =
+ internal_iserror(internal_ptrace(PT_GETREGS, ppid, &regs, tid), &pterrno);
+ if (isErr) {
+ VReport(1,
+ "Could not get registers from process %d thread %d (errno %d).\n",
+ ppid, tid, pterrno);
+ return pterrno == ESRCH ? REGISTERS_UNAVAILABLE_FATAL
+ : REGISTERS_UNAVAILABLE;
+ }
+
+ *sp = PTRACE_REG_SP(&regs);
+ internal_memcpy(buffer, &regs, sizeof(regs));
+
+ return REGISTERS_AVAILABLE;
+}
+
+uptr SuspendedThreadsListNetBSD::RegisterCount() const {
+ return sizeof(struct reg) / sizeof(uptr);
+}
+} // namespace __sanitizer
+
+#endif