From 10169d773dbca24595c7ff028543e4ce6f0191fe Mon Sep 17 00:00:00 2001
From: Bananymous <bananymousosq@gmail.com>
Date: Fri, 21 Jul 2023 19:27:38 +0300
Subject: [PATCH] Kernel/LibC: Add SYS_KILL/kill()

---
 kernel/include/kernel/Process.h |  2 +-
 kernel/kernel/Process.cpp       | 25 +++++++++++++++++++++++++
 kernel/kernel/Syscall.cpp       |  3 +++
 libc/include/sys/syscall.h      |  1 +
 libc/signal.cpp                 |  5 +++++
 libc/unistd.cpp                 |  7 +++++++
 userspace/Shell/main.cpp        | 21 +++++++++++++++++++--
 7 files changed, 61 insertions(+), 3 deletions(-)

diff --git a/kernel/include/kernel/Process.h b/kernel/include/kernel/Process.h
index 2dd291a757..9f2ae3a8aa 100644
--- a/kernel/include/kernel/Process.h
+++ b/kernel/include/kernel/Process.h
@@ -101,7 +101,7 @@ namespace Kernel
 		BAN::ErrorOr<long> sys_free(void*);
 
 		BAN::ErrorOr<long> sys_signal(int, void (*)(int));
-		BAN::ErrorOr<long> sys_kill(pid_t pid, int signal);
+		BAN::ErrorOr<long> sys_kill(pid_t pid, int signal, uintptr_t& return_rsp, uintptr_t& return_rip);
 		BAN::ErrorOr<long> sys_raise(int signal, uintptr_t& return_rsp, uintptr_t& return_rip);
 
 		BAN::ErrorOr<long> sys_termid(char*) const;
diff --git a/kernel/kernel/Process.cpp b/kernel/kernel/Process.cpp
index ace5a20c46..b346ca7eb4 100644
--- a/kernel/kernel/Process.cpp
+++ b/kernel/kernel/Process.cpp
@@ -789,6 +789,31 @@ namespace Kernel
 		return 0;
 	}
 
+	BAN::ErrorOr<long> Process::sys_kill(pid_t pid, int signal, uintptr_t& return_rsp, uintptr_t& return_rip)
+	{
+		if (pid <= 0)
+			return BAN::Error::from_errno(ENOTSUP);
+		if (signal != 0 && (signal < _SIGMIN || signal > _SIGMAX))
+			return BAN::Error::from_errno(EINVAL);
+
+		if (pid == this->pid())
+			return sys_raise(signal, return_rsp, return_rip);
+
+		LockGuard process_guard(s_process_lock);
+		CriticalScope _;
+		for (auto* process : s_processes)
+		{
+			if (process->pid() == pid)
+			{
+				if (signal)
+					process->m_threads.front()->m_signal_queue.push(signal);
+				return 0;
+			}
+		}
+
+		return BAN::Error::from_errno(ESRCH);
+	}
+
 	BAN::ErrorOr<long> Process::sys_raise(int signal, uintptr_t& return_rsp, uintptr_t& return_rip)
 	{
 		if (signal < _SIGMIN || signal > _SIGMAX)
diff --git a/kernel/kernel/Syscall.cpp b/kernel/kernel/Syscall.cpp
index 1171a87d08..9b4db9b60a 100644
--- a/kernel/kernel/Syscall.cpp
+++ b/kernel/kernel/Syscall.cpp
@@ -143,6 +143,9 @@ namespace Kernel
 		case SYS_RAISE:
 			ret = Process::current().sys_raise((int)arg1, interrupt_stack.rsp, interrupt_stack.rip);
 			break;
+		case SYS_KILL:
+			ret = Process::current().sys_kill((pid_t)arg1, (int)arg2, interrupt_stack.rsp, interrupt_stack.rip);
+			break;
 		default:
 			dwarnln("Unknown syscall {}", syscall);
 			break;
diff --git a/libc/include/sys/syscall.h b/libc/include/sys/syscall.h
index 677f694e6c..3ce74f298d 100644
--- a/libc/include/sys/syscall.h
+++ b/libc/include/sys/syscall.h
@@ -42,6 +42,7 @@ __BEGIN_DECLS
 #define SYS_PIPE 35
 #define SYS_DUP2 36
 #define SYS_RAISE 37
+#define SYS_KILL 38
 
 __END_DECLS
 
diff --git a/libc/signal.cpp b/libc/signal.cpp
index b15dfad6fc..93ce5e728e 100644
--- a/libc/signal.cpp
+++ b/libc/signal.cpp
@@ -5,4 +5,9 @@
 int raise(int sig)
 {
 	return syscall(SYS_RAISE, sig);
+}
+
+int kill(pid_t pid, int sig)
+{
+	return syscall(SYS_KILL, pid, sig);
 }
\ No newline at end of file
diff --git a/libc/unistd.cpp b/libc/unistd.cpp
index 1b15a22505..f4c2e8c1a2 100644
--- a/libc/unistd.cpp
+++ b/libc/unistd.cpp
@@ -272,6 +272,13 @@ long syscall(long syscall, ...)
 			ret = Kernel::syscall(SYS_RAISE, signal);
 			break;
 		}
+		case SYS_KILL:
+		{
+			pid_t pid = va_arg(args, pid_t);
+			int signal = va_arg(args, int);
+			ret = Kernel::syscall(SYS_KILL, pid, signal);
+			break;
+		}
 		default:
 			puts("LibC: Unhandeled syscall");
 			ret = -ENOSYS;
diff --git a/userspace/Shell/main.cpp b/userspace/Shell/main.cpp
index 4d119d550a..5309c29123 100644
--- a/userspace/Shell/main.cpp
+++ b/userspace/Shell/main.cpp
@@ -260,9 +260,26 @@ int execute_command(BAN::Vector<BAN::String>& args)
 		while (*current)
 			printf("%s\n", *current++);
 	}
-	else if (args.front() == "raise"sv)
+	else if (args.front() == "kill-test"sv)
 	{
-		raise(SIGSEGV);
+		pid_t pid = fork();
+		if (pid == 0)
+		{
+			printf("child\n");
+			for (;;);
+		}
+		if (pid == -1)
+		{
+			perror("fork");
+			return 1;
+		}
+
+		sleep(1);
+		if (kill(pid, SIGSEGV) == -1)
+		{
+			perror("kill");
+			return 1;
+		}
 	}
 	else if (args.front() == "cd"sv)
 	{