From 7314cf708cf0d5589e8d7406c2fd6aca5a580232 Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Sat, 28 Jun 2025 20:14:06 +0300
Subject: [PATCH] Kernel: Only restart certain syscalls with SA_RESTART

SA_RESTART is not supposted to restart every function.
---
 kernel/kernel/Syscall.cpp | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/kernel/kernel/Syscall.cpp b/kernel/kernel/Syscall.cpp
index b99ea1df..39a7bf1b 100644
--- a/kernel/kernel/Syscall.cpp
+++ b/kernel/kernel/Syscall.cpp
@@ -38,6 +38,8 @@ namespace Kernel
 #undef O
 	};
 
+	static bool is_restartable_syscall(int syscall);
+
 	extern "C" long cpp_syscall_handler(int syscall, uintptr_t arg1, uintptr_t arg2, uintptr_t arg3, uintptr_t arg4, uintptr_t arg5, InterruptStack* interrupt_stack)
 	{
 		ASSERT(GDT::is_user_segment(interrupt_stack->cs));
@@ -93,7 +95,7 @@ namespace Kernel
 		auto& current_thread = Thread::current();
 		if (current_thread.can_add_signal_to_execute())
 			if (current_thread.handle_signal())
-				if (ret.is_error() && ret.error().get_error_code() == EINTR)
+				if (ret.is_error() && ret.error().get_error_code() == EINTR && is_restartable_syscall(syscall))
 					ret = BAN::Error::from_errno(ERESTART);
 
 		Processor::set_interrupt_state(InterruptState::Disabled);
@@ -105,4 +107,26 @@ namespace Kernel
 		return ret.value();
 	}
 
+	bool is_restartable_syscall(int syscall)
+	{
+		// https://www.man7.org/linux/man-pages/man7/signal.7.html
+		// Interruption of system calls and library functions by signal handlers
+		switch (syscall)
+		{
+			case SYS_READ:
+			case SYS_WRITE:
+			case SYS_IOCTL:
+			case SYS_OPENAT:
+			case SYS_WAIT:
+			case SYS_ACCEPT:
+			case SYS_CONNECT:
+			case SYS_RECVFROM:
+			case SYS_SENDTO:
+			case SYS_FLOCK:
+				return true;
+			default:
+				return false;
+		}
+	}
+
 }