Don't skip check for warning at line 411 in Wattributes.c on hppa*64*-*-*
[official-gcc.git] / libsanitizer / sanitizer_common / sanitizer_stoptheworld_linux_libcdep.cpp
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1 //===-- sanitizer_stoptheworld_linux_libcdep.cpp --------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // See sanitizer_stoptheworld.h for details.
10 // This implementation was inspired by Markus Gutschke's linuxthreads.cc.
12 //===----------------------------------------------------------------------===//
14 #include "sanitizer_platform.h"
16 #if SANITIZER_LINUX && \
17 (defined(__x86_64__) || defined(__mips__) || defined(__aarch64__) || \
18 defined(__powerpc64__) || defined(__s390__) || defined(__i386__) || \
19 defined(__arm__) || SANITIZER_RISCV64 || SANITIZER_LOONGARCH64)
21 #include "sanitizer_stoptheworld.h"
23 #include "sanitizer_platform_limits_posix.h"
24 #include "sanitizer_atomic.h"
26 #include <errno.h>
27 #include <sched.h> // for CLONE_* definitions
28 #include <stddef.h>
29 #include <sys/prctl.h> // for PR_* definitions
30 #include <sys/ptrace.h> // for PTRACE_* definitions
31 #include <sys/types.h> // for pid_t
32 #include <sys/uio.h> // for iovec
33 #include <elf.h> // for NT_PRSTATUS
34 #if (defined(__aarch64__) || SANITIZER_RISCV64 || SANITIZER_LOONGARCH64) && \
35 !SANITIZER_ANDROID
36 // GLIBC 2.20+ sys/user does not include asm/ptrace.h
37 # include <asm/ptrace.h>
38 #endif
39 #include <sys/user.h> // for user_regs_struct
40 #if SANITIZER_ANDROID && SANITIZER_MIPS
41 # include <asm/reg.h> // for mips SP register in sys/user.h
42 #endif
43 #include <sys/wait.h> // for signal-related stuff
45 #ifdef sa_handler
46 # undef sa_handler
47 #endif
49 #ifdef sa_sigaction
50 # undef sa_sigaction
51 #endif
53 #include "sanitizer_common.h"
54 #include "sanitizer_flags.h"
55 #include "sanitizer_libc.h"
56 #include "sanitizer_linux.h"
57 #include "sanitizer_mutex.h"
58 #include "sanitizer_placement_new.h"
60 // Sufficiently old kernel headers don't provide this value, but we can still
61 // call prctl with it. If the runtime kernel is new enough, the prctl call will
62 // have the desired effect; if the kernel is too old, the call will error and we
63 // can ignore said error.
64 #ifndef PR_SET_PTRACER
65 #define PR_SET_PTRACER 0x59616d61
66 #endif
68 // This module works by spawning a Linux task which then attaches to every
69 // thread in the caller process with ptrace. This suspends the threads, and
70 // PTRACE_GETREGS can then be used to obtain their register state. The callback
71 // supplied to StopTheWorld() is run in the tracer task while the threads are
72 // suspended.
73 // The tracer task must be placed in a different thread group for ptrace to
74 // work, so it cannot be spawned as a pthread. Instead, we use the low-level
75 // clone() interface (we want to share the address space with the caller
76 // process, so we prefer clone() over fork()).
78 // We don't use any libc functions, relying instead on direct syscalls. There
79 // are two reasons for this:
80 // 1. calling a library function while threads are suspended could cause a
81 // deadlock, if one of the treads happens to be holding a libc lock;
82 // 2. it's generally not safe to call libc functions from the tracer task,
83 // because clone() does not set up a thread-local storage for it. Any
84 // thread-local variables used by libc will be shared between the tracer task
85 // and the thread which spawned it.
87 namespace __sanitizer {
89 class SuspendedThreadsListLinux final : public SuspendedThreadsList {
90 public:
91 SuspendedThreadsListLinux() { thread_ids_.reserve(1024); }
93 tid_t GetThreadID(uptr index) const override;
94 uptr ThreadCount() const override;
95 bool ContainsTid(tid_t thread_id) const;
96 void Append(tid_t tid);
98 PtraceRegistersStatus GetRegistersAndSP(uptr index,
99 InternalMmapVector<uptr> *buffer,
100 uptr *sp) const override;
102 private:
103 InternalMmapVector<tid_t> thread_ids_;
106 // Structure for passing arguments into the tracer thread.
107 struct TracerThreadArgument {
108 StopTheWorldCallback callback;
109 void *callback_argument;
110 // The tracer thread waits on this mutex while the parent finishes its
111 // preparations.
112 Mutex mutex;
113 // Tracer thread signals its completion by setting done.
114 atomic_uintptr_t done;
115 uptr parent_pid;
118 // This class handles thread suspending/unsuspending in the tracer thread.
119 class ThreadSuspender {
120 public:
121 explicit ThreadSuspender(pid_t pid, TracerThreadArgument *arg)
122 : arg(arg)
123 , pid_(pid) {
124 CHECK_GE(pid, 0);
126 bool SuspendAllThreads();
127 void ResumeAllThreads();
128 void KillAllThreads();
129 SuspendedThreadsListLinux &suspended_threads_list() {
130 return suspended_threads_list_;
132 TracerThreadArgument *arg;
133 private:
134 SuspendedThreadsListLinux suspended_threads_list_;
135 pid_t pid_;
136 bool SuspendThread(tid_t thread_id);
139 bool ThreadSuspender::SuspendThread(tid_t tid) {
140 // Are we already attached to this thread?
141 // Currently this check takes linear time, however the number of threads is
142 // usually small.
143 if (suspended_threads_list_.ContainsTid(tid)) return false;
144 int pterrno;
145 if (internal_iserror(internal_ptrace(PTRACE_ATTACH, tid, nullptr, nullptr),
146 &pterrno)) {
147 // Either the thread is dead, or something prevented us from attaching.
148 // Log this event and move on.
149 VReport(1, "Could not attach to thread %zu (errno %d).\n", (uptr)tid,
150 pterrno);
151 return false;
152 } else {
153 VReport(2, "Attached to thread %zu.\n", (uptr)tid);
154 // The thread is not guaranteed to stop before ptrace returns, so we must
155 // wait on it. Note: if the thread receives a signal concurrently,
156 // we can get notification about the signal before notification about stop.
157 // In such case we need to forward the signal to the thread, otherwise
158 // the signal will be missed (as we do PTRACE_DETACH with arg=0) and
159 // any logic relying on signals will break. After forwarding we need to
160 // continue to wait for stopping, because the thread is not stopped yet.
161 // We do ignore delivery of SIGSTOP, because we want to make stop-the-world
162 // as invisible as possible.
163 for (;;) {
164 int status;
165 uptr waitpid_status;
166 HANDLE_EINTR(waitpid_status, internal_waitpid(tid, &status, __WALL));
167 int wperrno;
168 if (internal_iserror(waitpid_status, &wperrno)) {
169 // Got a ECHILD error. I don't think this situation is possible, but it
170 // doesn't hurt to report it.
171 VReport(1, "Waiting on thread %zu failed, detaching (errno %d).\n",
172 (uptr)tid, wperrno);
173 internal_ptrace(PTRACE_DETACH, tid, nullptr, nullptr);
174 return false;
176 if (WIFSTOPPED(status) && WSTOPSIG(status) != SIGSTOP) {
177 internal_ptrace(PTRACE_CONT, tid, nullptr,
178 (void*)(uptr)WSTOPSIG(status));
179 continue;
181 break;
183 suspended_threads_list_.Append(tid);
184 return true;
188 void ThreadSuspender::ResumeAllThreads() {
189 for (uptr i = 0; i < suspended_threads_list_.ThreadCount(); i++) {
190 pid_t tid = suspended_threads_list_.GetThreadID(i);
191 int pterrno;
192 if (!internal_iserror(internal_ptrace(PTRACE_DETACH, tid, nullptr, nullptr),
193 &pterrno)) {
194 VReport(2, "Detached from thread %d.\n", tid);
195 } else {
196 // Either the thread is dead, or we are already detached.
197 // The latter case is possible, for instance, if this function was called
198 // from a signal handler.
199 VReport(1, "Could not detach from thread %d (errno %d).\n", tid, pterrno);
204 void ThreadSuspender::KillAllThreads() {
205 for (uptr i = 0; i < suspended_threads_list_.ThreadCount(); i++)
206 internal_ptrace(PTRACE_KILL, suspended_threads_list_.GetThreadID(i),
207 nullptr, nullptr);
210 bool ThreadSuspender::SuspendAllThreads() {
211 ThreadLister thread_lister(pid_);
212 bool retry = true;
213 InternalMmapVector<tid_t> threads;
214 threads.reserve(128);
215 for (int i = 0; i < 30 && retry; ++i) {
216 retry = false;
217 switch (thread_lister.ListThreads(&threads)) {
218 case ThreadLister::Error:
219 ResumeAllThreads();
220 return false;
221 case ThreadLister::Incomplete:
222 retry = true;
223 break;
224 case ThreadLister::Ok:
225 break;
227 for (tid_t tid : threads) {
228 if (SuspendThread(tid))
229 retry = true;
232 return suspended_threads_list_.ThreadCount();
235 // Pointer to the ThreadSuspender instance for use in signal handler.
236 static ThreadSuspender *thread_suspender_instance = nullptr;
238 // Synchronous signals that should not be blocked.
239 static const int kSyncSignals[] = { SIGABRT, SIGILL, SIGFPE, SIGSEGV, SIGBUS,
240 SIGXCPU, SIGXFSZ };
242 static void TracerThreadDieCallback() {
243 // Generally a call to Die() in the tracer thread should be fatal to the
244 // parent process as well, because they share the address space.
245 // This really only works correctly if all the threads are suspended at this
246 // point. So we correctly handle calls to Die() from within the callback, but
247 // not those that happen before or after the callback. Hopefully there aren't
248 // a lot of opportunities for that to happen...
249 ThreadSuspender *inst = thread_suspender_instance;
250 if (inst && stoptheworld_tracer_pid == internal_getpid()) {
251 inst->KillAllThreads();
252 thread_suspender_instance = nullptr;
256 // Signal handler to wake up suspended threads when the tracer thread dies.
257 static void TracerThreadSignalHandler(int signum, __sanitizer_siginfo *siginfo,
258 void *uctx) {
259 SignalContext ctx(siginfo, uctx);
260 Printf("Tracer caught signal %d: addr=0x%zx pc=0x%zx sp=0x%zx\n", signum,
261 ctx.addr, ctx.pc, ctx.sp);
262 ThreadSuspender *inst = thread_suspender_instance;
263 if (inst) {
264 if (signum == SIGABRT)
265 inst->KillAllThreads();
266 else
267 inst->ResumeAllThreads();
268 RAW_CHECK(RemoveDieCallback(TracerThreadDieCallback));
269 thread_suspender_instance = nullptr;
270 atomic_store(&inst->arg->done, 1, memory_order_relaxed);
272 internal__exit((signum == SIGABRT) ? 1 : 2);
275 // Size of alternative stack for signal handlers in the tracer thread.
276 static const int kHandlerStackSize = 8192;
278 // This function will be run as a cloned task.
279 static int TracerThread(void* argument) {
280 TracerThreadArgument *tracer_thread_argument =
281 (TracerThreadArgument *)argument;
283 internal_prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
284 // Check if parent is already dead.
285 if (internal_getppid() != tracer_thread_argument->parent_pid)
286 internal__exit(4);
288 // Wait for the parent thread to finish preparations.
289 tracer_thread_argument->mutex.Lock();
290 tracer_thread_argument->mutex.Unlock();
292 RAW_CHECK(AddDieCallback(TracerThreadDieCallback));
294 ThreadSuspender thread_suspender(internal_getppid(), tracer_thread_argument);
295 // Global pointer for the signal handler.
296 thread_suspender_instance = &thread_suspender;
298 // Alternate stack for signal handling.
299 InternalMmapVector<char> handler_stack_memory(kHandlerStackSize);
300 stack_t handler_stack;
301 internal_memset(&handler_stack, 0, sizeof(handler_stack));
302 handler_stack.ss_sp = handler_stack_memory.data();
303 handler_stack.ss_size = kHandlerStackSize;
304 internal_sigaltstack(&handler_stack, nullptr);
306 // Install our handler for synchronous signals. Other signals should be
307 // blocked by the mask we inherited from the parent thread.
308 for (uptr i = 0; i < ARRAY_SIZE(kSyncSignals); i++) {
309 __sanitizer_sigaction act;
310 internal_memset(&act, 0, sizeof(act));
311 act.sigaction = TracerThreadSignalHandler;
312 act.sa_flags = SA_ONSTACK | SA_SIGINFO;
313 internal_sigaction_norestorer(kSyncSignals[i], &act, 0);
316 int exit_code = 0;
317 if (!thread_suspender.SuspendAllThreads()) {
318 VReport(1, "Failed suspending threads.\n");
319 exit_code = 3;
320 } else {
321 tracer_thread_argument->callback(thread_suspender.suspended_threads_list(),
322 tracer_thread_argument->callback_argument);
323 thread_suspender.ResumeAllThreads();
324 exit_code = 0;
326 RAW_CHECK(RemoveDieCallback(TracerThreadDieCallback));
327 thread_suspender_instance = nullptr;
328 atomic_store(&tracer_thread_argument->done, 1, memory_order_relaxed);
329 return exit_code;
332 class ScopedStackSpaceWithGuard {
333 public:
334 explicit ScopedStackSpaceWithGuard(uptr stack_size) {
335 stack_size_ = stack_size;
336 guard_size_ = GetPageSizeCached();
337 // FIXME: Omitting MAP_STACK here works in current kernels but might break
338 // in the future.
339 guard_start_ = (uptr)MmapOrDie(stack_size_ + guard_size_,
340 "ScopedStackWithGuard");
341 CHECK(MprotectNoAccess((uptr)guard_start_, guard_size_));
343 ~ScopedStackSpaceWithGuard() {
344 UnmapOrDie((void *)guard_start_, stack_size_ + guard_size_);
346 void *Bottom() const {
347 return (void *)(guard_start_ + stack_size_ + guard_size_);
350 private:
351 uptr stack_size_;
352 uptr guard_size_;
353 uptr guard_start_;
356 // We have a limitation on the stack frame size, so some stuff had to be moved
357 // into globals.
358 static __sanitizer_sigset_t blocked_sigset;
359 static __sanitizer_sigset_t old_sigset;
361 class StopTheWorldScope {
362 public:
363 StopTheWorldScope() {
364 // Make this process dumpable. Processes that are not dumpable cannot be
365 // attached to.
366 process_was_dumpable_ = internal_prctl(PR_GET_DUMPABLE, 0, 0, 0, 0);
367 if (!process_was_dumpable_)
368 internal_prctl(PR_SET_DUMPABLE, 1, 0, 0, 0);
371 ~StopTheWorldScope() {
372 // Restore the dumpable flag.
373 if (!process_was_dumpable_)
374 internal_prctl(PR_SET_DUMPABLE, 0, 0, 0, 0);
377 private:
378 int process_was_dumpable_;
381 // When sanitizer output is being redirected to file (i.e. by using log_path),
382 // the tracer should write to the parent's log instead of trying to open a new
383 // file. Alert the logging code to the fact that we have a tracer.
384 struct ScopedSetTracerPID {
385 explicit ScopedSetTracerPID(uptr tracer_pid) {
386 stoptheworld_tracer_pid = tracer_pid;
387 stoptheworld_tracer_ppid = internal_getpid();
389 ~ScopedSetTracerPID() {
390 stoptheworld_tracer_pid = 0;
391 stoptheworld_tracer_ppid = 0;
395 void StopTheWorld(StopTheWorldCallback callback, void *argument) {
396 StopTheWorldScope in_stoptheworld;
397 // Prepare the arguments for TracerThread.
398 struct TracerThreadArgument tracer_thread_argument;
399 tracer_thread_argument.callback = callback;
400 tracer_thread_argument.callback_argument = argument;
401 tracer_thread_argument.parent_pid = internal_getpid();
402 atomic_store(&tracer_thread_argument.done, 0, memory_order_relaxed);
403 const uptr kTracerStackSize = 2 * 1024 * 1024;
404 ScopedStackSpaceWithGuard tracer_stack(kTracerStackSize);
405 // Block the execution of TracerThread until after we have set ptrace
406 // permissions.
407 tracer_thread_argument.mutex.Lock();
408 // Signal handling story.
409 // We don't want async signals to be delivered to the tracer thread,
410 // so we block all async signals before creating the thread. An async signal
411 // handler can temporary modify errno, which is shared with this thread.
412 // We ought to use pthread_sigmask here, because sigprocmask has undefined
413 // behavior in multithreaded programs. However, on linux sigprocmask is
414 // equivalent to pthread_sigmask with the exception that pthread_sigmask
415 // does not allow to block some signals used internally in pthread
416 // implementation. We are fine with blocking them here, we are really not
417 // going to pthread_cancel the thread.
418 // The tracer thread should not raise any synchronous signals. But in case it
419 // does, we setup a special handler for sync signals that properly kills the
420 // parent as well. Note: we don't pass CLONE_SIGHAND to clone, so handlers
421 // in the tracer thread won't interfere with user program. Double note: if a
422 // user does something along the lines of 'kill -11 pid', that can kill the
423 // process even if user setup own handler for SEGV.
424 // Thing to watch out for: this code should not change behavior of user code
425 // in any observable way. In particular it should not override user signal
426 // handlers.
427 internal_sigfillset(&blocked_sigset);
428 for (uptr i = 0; i < ARRAY_SIZE(kSyncSignals); i++)
429 internal_sigdelset(&blocked_sigset, kSyncSignals[i]);
430 int rv = internal_sigprocmask(SIG_BLOCK, &blocked_sigset, &old_sigset);
431 CHECK_EQ(rv, 0);
432 uptr tracer_pid = internal_clone(
433 TracerThread, tracer_stack.Bottom(),
434 CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_UNTRACED,
435 &tracer_thread_argument, nullptr /* parent_tidptr */,
436 nullptr /* newtls */, nullptr /* child_tidptr */);
437 internal_sigprocmask(SIG_SETMASK, &old_sigset, 0);
438 int local_errno = 0;
439 if (internal_iserror(tracer_pid, &local_errno)) {
440 VReport(1, "Failed spawning a tracer thread (errno %d).\n", local_errno);
441 tracer_thread_argument.mutex.Unlock();
442 } else {
443 ScopedSetTracerPID scoped_set_tracer_pid(tracer_pid);
444 // On some systems we have to explicitly declare that we want to be traced
445 // by the tracer thread.
446 internal_prctl(PR_SET_PTRACER, tracer_pid, 0, 0, 0);
447 // Allow the tracer thread to start.
448 tracer_thread_argument.mutex.Unlock();
449 // NOTE: errno is shared between this thread and the tracer thread.
450 // internal_waitpid() may call syscall() which can access/spoil errno,
451 // so we can't call it now. Instead we for the tracer thread to finish using
452 // the spin loop below. Man page for sched_yield() says "In the Linux
453 // implementation, sched_yield() always succeeds", so let's hope it does not
454 // spoil errno. Note that this spin loop runs only for brief periods before
455 // the tracer thread has suspended us and when it starts unblocking threads.
456 while (atomic_load(&tracer_thread_argument.done, memory_order_relaxed) == 0)
457 sched_yield();
458 // Now the tracer thread is about to exit and does not touch errno,
459 // wait for it.
460 for (;;) {
461 uptr waitpid_status = internal_waitpid(tracer_pid, nullptr, __WALL);
462 if (!internal_iserror(waitpid_status, &local_errno))
463 break;
464 if (local_errno == EINTR)
465 continue;
466 VReport(1, "Waiting on the tracer thread failed (errno %d).\n",
467 local_errno);
468 break;
473 // Platform-specific methods from SuspendedThreadsList.
474 #if SANITIZER_ANDROID && defined(__arm__)
475 typedef pt_regs regs_struct;
476 #define REG_SP ARM_sp
478 #elif SANITIZER_LINUX && defined(__arm__)
479 typedef user_regs regs_struct;
480 #define REG_SP uregs[13]
482 #elif defined(__i386__) || defined(__x86_64__)
483 typedef user_regs_struct regs_struct;
484 #if defined(__i386__)
485 #define REG_SP esp
486 #else
487 #define REG_SP rsp
488 #endif
489 #define ARCH_IOVEC_FOR_GETREGSET
490 // Support ptrace extensions even when compiled without required kernel support
491 #ifndef NT_X86_XSTATE
492 #define NT_X86_XSTATE 0x202
493 #endif
494 #ifndef PTRACE_GETREGSET
495 #define PTRACE_GETREGSET 0x4204
496 #endif
497 // Compiler may use FP registers to store pointers.
498 static constexpr uptr kExtraRegs[] = {NT_X86_XSTATE, NT_FPREGSET};
500 #elif defined(__powerpc__) || defined(__powerpc64__)
501 typedef pt_regs regs_struct;
502 #define REG_SP gpr[PT_R1]
504 #elif defined(__mips__)
505 typedef struct user regs_struct;
506 # if SANITIZER_ANDROID
507 # define REG_SP regs[EF_R29]
508 # else
509 # define REG_SP regs[EF_REG29]
510 # endif
512 #elif defined(__aarch64__)
513 typedef struct user_pt_regs regs_struct;
514 #define REG_SP sp
515 static constexpr uptr kExtraRegs[] = {0};
516 #define ARCH_IOVEC_FOR_GETREGSET
518 #elif defined(__loongarch__)
519 typedef struct user_pt_regs regs_struct;
520 #define REG_SP regs[3]
521 static constexpr uptr kExtraRegs[] = {0};
522 #define ARCH_IOVEC_FOR_GETREGSET
524 #elif SANITIZER_RISCV64
525 typedef struct user_regs_struct regs_struct;
526 // sys/ucontext.h already defines REG_SP as 2. Undefine it first.
527 #undef REG_SP
528 #define REG_SP sp
529 static constexpr uptr kExtraRegs[] = {0};
530 #define ARCH_IOVEC_FOR_GETREGSET
532 #elif defined(__s390__)
533 typedef _user_regs_struct regs_struct;
534 #define REG_SP gprs[15]
535 static constexpr uptr kExtraRegs[] = {0};
536 #define ARCH_IOVEC_FOR_GETREGSET
538 #else
539 #error "Unsupported architecture"
540 #endif // SANITIZER_ANDROID && defined(__arm__)
542 tid_t SuspendedThreadsListLinux::GetThreadID(uptr index) const {
543 CHECK_LT(index, thread_ids_.size());
544 return thread_ids_[index];
547 uptr SuspendedThreadsListLinux::ThreadCount() const {
548 return thread_ids_.size();
551 bool SuspendedThreadsListLinux::ContainsTid(tid_t thread_id) const {
552 for (uptr i = 0; i < thread_ids_.size(); i++) {
553 if (thread_ids_[i] == thread_id) return true;
555 return false;
558 void SuspendedThreadsListLinux::Append(tid_t tid) {
559 thread_ids_.push_back(tid);
562 PtraceRegistersStatus SuspendedThreadsListLinux::GetRegistersAndSP(
563 uptr index, InternalMmapVector<uptr> *buffer, uptr *sp) const {
564 pid_t tid = GetThreadID(index);
565 constexpr uptr uptr_sz = sizeof(uptr);
566 int pterrno;
567 #ifdef ARCH_IOVEC_FOR_GETREGSET
568 auto AppendF = [&](uptr regset) {
569 uptr size = buffer->size();
570 // NT_X86_XSTATE requires 64bit alignment.
571 uptr size_up = RoundUpTo(size, 8 / uptr_sz);
572 buffer->reserve(Max<uptr>(1024, size_up));
573 struct iovec regset_io;
574 for (;; buffer->resize(buffer->capacity() * 2)) {
575 buffer->resize(buffer->capacity());
576 uptr available_bytes = (buffer->size() - size_up) * uptr_sz;
577 regset_io.iov_base = buffer->data() + size_up;
578 regset_io.iov_len = available_bytes;
579 bool fail =
580 internal_iserror(internal_ptrace(PTRACE_GETREGSET, tid,
581 (void *)regset, (void *)&regset_io),
582 &pterrno);
583 if (fail) {
584 VReport(1, "Could not get regset %p from thread %d (errno %d).\n",
585 (void *)regset, tid, pterrno);
586 buffer->resize(size);
587 return false;
590 // Far enough from the buffer size, no need to resize and repeat.
591 if (regset_io.iov_len + 64 < available_bytes)
592 break;
594 buffer->resize(size_up + RoundUpTo(regset_io.iov_len, uptr_sz) / uptr_sz);
595 return true;
598 buffer->clear();
599 bool fail = !AppendF(NT_PRSTATUS);
600 if (!fail) {
601 // Accept the first available and do not report errors.
602 for (uptr regs : kExtraRegs)
603 if (regs && AppendF(regs))
604 break;
606 #else
607 buffer->resize(RoundUpTo(sizeof(regs_struct), uptr_sz) / uptr_sz);
608 bool fail = internal_iserror(
609 internal_ptrace(PTRACE_GETREGS, tid, nullptr, buffer->data()), &pterrno);
610 if (fail)
611 VReport(1, "Could not get registers from thread %d (errno %d).\n", tid,
612 pterrno);
613 #endif
614 if (fail) {
615 // ESRCH means that the given thread is not suspended or already dead.
616 // Therefore it's unsafe to inspect its data (e.g. walk through stack) and
617 // we should notify caller about this.
618 return pterrno == ESRCH ? REGISTERS_UNAVAILABLE_FATAL
619 : REGISTERS_UNAVAILABLE;
622 *sp = reinterpret_cast<regs_struct *>(buffer->data())[0].REG_SP;
623 return REGISTERS_AVAILABLE;
626 } // namespace __sanitizer
628 #endif // SANITIZER_LINUX && (defined(__x86_64__) || defined(__mips__)
629 // || defined(__aarch64__) || defined(__powerpc64__)
630 // || defined(__s390__) || defined(__i386__) || defined(__arm__)
631 // || SANITIZER_LOONGARCH64