Merge pull request #884 from Geertiebear/cancelable_syscalls

Changes for managarm cancelable syscalls

Author: no92

sysdeps/managarm/generic/entry.cpp

@@ -28,6 +28,7 @@ namespace {
 thread_local unsigned __mlibc_gsf_nesting;
 thread_local void *__mlibc_cached_thread_page;
 thread_local HelHandle *cachedFileTable;
+thread_local HelHandle *cancelEvent;
 
 // This construction is a bit weird: Even though the variables above
 // are thread_local we still protect their initialization with a pthread_once_t
@@ -45,6 +46,7 @@ void actuallyCacheInfos() {
 	__mlibc_cached_thread_page = data.threadPage;
 	cachedFileTable = data.fileTable;
 	__mlibc_clk_tracker_page = data.clockTrackerPage;
+	cancelEvent = data.cancelRequestEvent;
 }
 } // namespace
 
@@ -104,6 +106,11 @@ HelHandle getHandleForFd(int fd) {
 
 void clearCachedInfos() { has_cached_infos = PTHREAD_ONCE_INIT; }
 
+void setCurrentRequestEvent(HelHandle event) {
+	pthread_once(&has_cached_infos, &actuallyCacheInfos);
+	__atomic_store_n(cancelEvent, event, __ATOMIC_RELEASE);
+}
+
 extern char **environ;
 
 extern "C" void

sysdeps/managarm/generic/file.cpp

@@ -1748,6 +1748,10 @@ int sys_read(int fd, void *data, size_t max_size, ssize_t *bytes_read) {
 	if (!handle)
 		return EBADF;
 
+	HelHandle cancel_handle;
+	HEL_CHECK(helCreateOneshotEvent(&cancel_handle));
+	helix::UniqueDescriptor cancel_event{cancel_handle};
+
 	managarm::fs::CntRequest<MemoryAllocator> req(getSysdepsAllocator());
 	req.set_req_type(managarm::fs::CntReqType::READ);
 	req.set_fd(fd);
@@ -1756,29 +1760,31 @@ int sys_read(int fd, void *data, size_t max_size, ssize_t *bytes_read) {
 	frg::string<MemoryAllocator> ser(getSysdepsAllocator());
 	req.SerializeToString(&ser);
 
-	auto [offer, send_req, imbue_creds, recv_resp, recv_data] = exchangeMsgsSync(
-	    handle,
-	    helix_ng::offer(
-	        helix_ng::sendBuffer(ser.data(), ser.size()),
-	        helix_ng::imbueCredentials(),
-	        helix_ng::recvInline(),
-	        helix_ng::recvBuffer(data, max_size)
-	    )
-	);
+	auto [offer, push_req, send_req, imbue_creds, recv_resp, recv_data] =
+	    exchangeMsgsSyncCancellable(
+	        handle,
+	        cancel_handle,
+	        helix_ng::offer(
+	            helix_ng::sendBuffer(ser.data(), ser.size()),
+	            helix_ng::pushDescriptor(cancel_event),
+	            helix_ng::imbueCredentials(),
+	            helix_ng::recvInline(),
+	            helix_ng::recvBuffer(data, max_size)
+	        )
+	    );
 
 	HEL_CHECK(offer.error());
+	HEL_CHECK(push_req.error());
 	HEL_CHECK(send_req.error());
 	HEL_CHECK(imbue_creds.error());
 	HEL_CHECK(recv_resp.error());
 
 	managarm::fs::SvrResponse<MemoryAllocator> resp(getSysdepsAllocator());
 	resp.ParseFromArray(recv_resp.data(), recv_resp.length());
-	if (resp.error() != managarm::fs::Errors::SUCCESS)
-		return resp.error() | toErrno;
-
 	HEL_CHECK(recv_data.error());
+
 	*bytes_read = recv_data.actualLength();
-	return 0;
+	return resp.error() | toErrno;
 }
 
 int sys_readv(int fd, const struct iovec *iovs, int iovc, ssize_t *bytes_read) {

sysdeps/managarm/generic/fork-exec.cpp

@@ -57,20 +57,33 @@ int sys_futex_wake(int *pointer) {
 int sys_waitpid(pid_t pid, int *status, int flags, struct rusage *ru, pid_t *ret_pid) {
 	SignalGuard sguard;
 
+	if (ru) {
+		mlibc::infoLogger() << "mlibc: struct rusage in sys_waitpid is unsupported" << frg::endlog;
+		return ENOSYS;
+	}
+
+	HelHandle cancel_handle;
+	HEL_CHECK(helCreateOneshotEvent(&cancel_handle));
+	helix::UniqueDescriptor cancel_event{cancel_handle};
+
 	managarm::posix::CntRequest<MemoryAllocator> req(getSysdepsAllocator());
 	req.set_request_type(managarm::posix::CntReqType::WAIT);
 	req.set_pid(pid);
 	req.set_flags(flags);
 
-	auto [offer, send_head, recv_resp] = exchangeMsgsSync(
+	auto [offer, send_head, push_descriptor, recv_resp] = exchangeMsgsSyncCancellable(
 	    getPosixLane(),
+	    cancel_handle,
 	    helix_ng::offer(
-	        helix_ng::sendBragiHeadOnly(req, getSysdepsAllocator()), helix_ng::recvInline()
+	        helix_ng::sendBragiHeadOnly(req, getSysdepsAllocator()),
+	        helix_ng::pushDescriptor(cancel_event),
+	        helix_ng::recvInline()
 	    )
 	);
 
 	HEL_CHECK(offer.error());
 	HEL_CHECK(send_head.error());
+	HEL_CHECK(push_descriptor.error());
 	HEL_CHECK(recv_resp.error());
 
 	managarm::posix::SvrResponse<MemoryAllocator> resp(getSysdepsAllocator());

sysdeps/managarm/include/bits/errors.hpp

@@ -76,6 +76,8 @@ inline int operator|(managarm::fs::Errors e, ToErrno) {
 			return ENOTSOCK;
 		case managarm::fs::Errors::INTERNAL_ERROR:
 			return EIO;
+		case managarm::fs::Errors::INTERRUPTED:
+			return EINTR;
 	}
 
 	mlibc::panicLogger() << "unhandled managarm::fs::Errors " << static_cast<int32_t>(e)
@@ -145,6 +147,8 @@ inline int operator|(managarm::posix::Errors e, ToErrno) {
 			return EISCONN;
 		case managarm::posix::Errors::UNSUPPORTED_SOCKET_TYPE:
 			return ESOCKTNOSUPPORT;
+		case managarm::posix::Errors::INTERRUPTED:
+			return EINTR;
 	}
 
 	mlibc::panicLogger() << "unhandled managarm::posix::Errors " << static_cast<int32_t>(e)

sysdeps/managarm/include/mlibc/posix-pipe.hpp

@@ -2,13 +2,16 @@
 #define MLIBC_POSIX_PIPE
 
 #include <cstddef>
-#include <signal.h>
-#include <stdint.h>
 #include <string.h>
 
 #include <hel-syscalls.h>
 #include <hel.h>
 
+#include <bits/ensure.h>
+#include <frg/optional.hpp>
+#include <mlibc/allocator.hpp>
+#include <mlibc/debug.hpp>
+
 struct SignalGuard {
 	SignalGuard();
 
@@ -121,24 +124,26 @@ struct Queue {
 
 	void trim() {}
 
-	ElementHandle dequeueSingle() {
+	frg::optional<ElementHandle> dequeueSingleUnlessCancelled() {
 		while (true) {
 			__ensure(_retrieveIndex != _nextIndex);
 
-			bool done;
-			_waitProgressFutex(&done);
+			auto progress = _waitProgressFutex();
 
 			auto n = _numberOf(_retrieveIndex);
 			__ensure(_refCount[n]);
 
-			if (done) {
+			if (progress == FutexProgress::DONE) {
 				retire(n);
 
 				_lastProgress = 0;
 				_retrieveIndex = ((_retrieveIndex + 1) & kHelHeadMask);
 				continue;
 			}
 
+			if (progress == FutexProgress::CANCELLED)
+				return frg::null_opt;
+
 			// Dequeue the next element.
 			auto ptr = (char *)_chunks[n] + sizeof(HelChunk) + _lastProgress;
 			auto element = reinterpret_cast<HelElement *>(ptr);
@@ -148,6 +153,14 @@ struct Queue {
 		}
 	}
 
+	ElementHandle dequeueSingle() {
+		while (true) {
+			auto result = dequeueSingleUnlessCancelled();
+			if (result)
+				return *result;
+		}
+	}
+
 	void retire(int n) {
 		__ensure(_refCount[n]);
 		if (_refCount[n]-- > 1)
@@ -175,18 +188,21 @@ struct Queue {
 			HEL_CHECK(helFutexWake(&_queue->headFutex));
 	}
 
-	void _waitProgressFutex(bool *done) {
+	enum class FutexProgress {
+		DONE,
+		PROGRESS,
+		CANCELLED,
+	};
+
+	FutexProgress _waitProgressFutex() {
 		while (true) {
 			auto futex = __atomic_load_n(&_retrieveChunk()->progressFutex, __ATOMIC_ACQUIRE);
 			__ensure(!(futex & ~(kHelProgressMask | kHelProgressWaiters | kHelProgressDone)));
 			do {
-				if (_lastProgress != (futex & kHelProgressMask)) {
-					*done = false;
-					return;
-				} else if (futex & kHelProgressDone) {
-					*done = true;
-					return;
-				}
+				if (_lastProgress != (futex & kHelProgressMask))
+					return FutexProgress::PROGRESS;
+				else if (futex & kHelProgressDone)
+					return FutexProgress::DONE;
 
 				if (futex & kHelProgressWaiters)
 					break; // Waiters bit is already set (in a previous iteration).
@@ -199,9 +215,14 @@ struct Queue {
 			    __ATOMIC_ACQUIRE
 			));
 
-			HEL_CHECK(helFutexWait(
+			int err = helFutexWait(
 			    &_retrieveChunk()->progressFutex, _lastProgress | kHelProgressWaiters, -1
-			));
+			);
+
+			if (err == kHelErrCancelled)
+				return FutexProgress::CANCELLED;
+
+			HEL_CHECK(err);
 		}
 	}
 
@@ -261,6 +282,7 @@ inline HelHandleResult *parseHandle(ElementHandle &element) {
 HelHandle getPosixLane();
 HelHandle *cacheFileTable();
 HelHandle getHandleForFd(int fd);
+void setCurrentRequestEvent(HelHandle event);
 void clearCachedInfos();
 
 extern thread_local Queue globalQueue;
@@ -287,4 +309,26 @@ auto exchangeMsgsSync(HelHandle descriptor, Args &&...args) {
 	return results;
 }
 
+template <typename... Args>
+auto exchangeMsgsSyncCancellable(HelHandle descriptor, HelHandle event, Args &&...args) {
+	auto results = helix_ng::createResultsTuple(args...);
+	auto actions = helix_ng::chainActionArrays(args...);
+
+	setCurrentRequestEvent(event);
+	HEL_CHECK(
+	    helSubmitAsync(descriptor, actions.data(), actions.size(), globalQueue.getQueue(), 0, 0)
+	);
+
+	auto element = globalQueue.dequeueSingle();
+	void *ptr = element.data();
+
+	[&]<size_t... p>(std::index_sequence<p...>) {
+		(results.template get<p>().parse(ptr, element), ...);
+	}(std::make_index_sequence<std::tuple_size_v<decltype(results)>>{});
+
+	setCurrentRequestEvent(kHelNullHandle);
+
+	return results;
+}
+
 #endif // MLIBC_POSIX_PIPE

sysdeps/managarm/rtld-generic/support.cpp

@@ -143,8 +143,10 @@ struct Queue {
 			    __ATOMIC_ACQUIRE
 			));
 
-			HEL_CHECK(helFutexWait(&_chunk->progressFutex, _lastProgress | kHelProgressWaiters, -1)
-			);
+			int err = helFutexWait(&_chunk->progressFutex, _lastProgress | kHelProgressWaiters, -1);
+			if (err == kHelErrCancelled)
+				continue;
+			HEL_CHECK(err);
 		}
 	}
 
@@ -302,7 +304,10 @@ int sys_seek(int fd, off_t offset, int whence, off_t *new_offset) {
 int sys_read(int fd, void *data, size_t length, ssize_t *bytes_read) {
 	cacheFileTable();
 	auto lane = fileTable[fd];
-	HelAction actions[5];
+	HelAction actions[6];
+
+	HelHandle cancel_handle;
+	HEL_CHECK(helCreateOneshotEvent(&cancel_handle));
 
 	managarm::fs::CntRequest<MemoryAllocator> req(getAllocator());
 	req.set_req_type(managarm::fs::CntReqType::READ);
@@ -319,25 +324,30 @@ int sys_read(int fd, void *data, size_t length, ssize_t *bytes_read) {
 	actions[1].flags = kHelItemChain;
 	actions[1].buffer = ser.data();
 	actions[1].length = ser.size();
-	actions[2].type = kHelActionImbueCredentials;
-	actions[2].handle = kHelThisThread;
+	actions[2].type = kHelActionPushDescriptor;
+	actions[2].handle = cancel_handle;
 	actions[2].flags = kHelItemChain;
-	actions[3].type = kHelActionRecvInline;
+	actions[3].type = kHelActionImbueCredentials;
+	actions[3].handle = kHelThisThread;
 	actions[3].flags = kHelItemChain;
-	actions[4].type = kHelActionRecvToBuffer;
-	actions[4].flags = 0;
-	actions[4].buffer = data;
-	actions[4].length = length;
-	HEL_CHECK(helSubmitAsync(lane, actions, 5, globalQueue->getHandle(), 0, 0));
+	actions[4].type = kHelActionRecvInline;
+	actions[4].flags = kHelItemChain;
+	actions[5].type = kHelActionRecvToBuffer;
+	actions[5].flags = 0;
+	actions[5].buffer = data;
+	actions[5].length = length;
+	HEL_CHECK(helSubmitAsync(lane, actions, 6, globalQueue->getHandle(), 0, 0));
 
 	auto element = globalQueue->dequeueSingle();
 	auto offer = parseHandle(element);
 	auto send_req = parseSimple(element);
+	auto push_desc = parseSimple(element);
 	auto imbue_creds = parseSimple(element);
 	auto recv_resp = parseInline(element);
 	auto recv_data = parseLength(element);
 	HEL_CHECK(offer->error);
 	HEL_CHECK(send_req->error);
+	HEL_CHECK(push_desc->error);
 	HEL_CHECK(imbue_creds->error);
 	HEL_CHECK(recv_resp->error);
 	HEL_CHECK(recv_data->error);