Kernel/LibC: Implement `getpeername`

kernel/include/kernel/FS/Inode.h

@@ -111,6 +111,7 @@ namespace Kernel
 		BAN::ErrorOr<size_t> sendto(BAN::ConstByteSpan message, const sockaddr* address, socklen_t address_len);
 		BAN::ErrorOr<size_t> recvfrom(BAN::ByteSpan buffer, sockaddr* address, socklen_t* address_len);
 		BAN::ErrorOr<void> getsockname(sockaddr* address, socklen_t* address_len);
+		BAN::ErrorOr<void> getpeername(sockaddr* address, socklen_t* address_len);
 
 		// General API
 		BAN::ErrorOr<size_t> read(off_t, BAN::ByteSpan buffer);
@@ -153,6 +154,7 @@ namespace Kernel
 		virtual BAN::ErrorOr<size_t> sendto_impl(BAN::ConstByteSpan, const sockaddr*, socklen_t)	{ return BAN::Error::from_errno(ENOTSUP); }
 		virtual BAN::ErrorOr<size_t> recvfrom_impl(BAN::ByteSpan, sockaddr*, socklen_t*)			{ return BAN::Error::from_errno(ENOTSUP); }
 		virtual BAN::ErrorOr<void> getsockname_impl(sockaddr*, socklen_t*)							{ return BAN::Error::from_errno(ENOTSUP); }
+		virtual BAN::ErrorOr<void> getpeername_impl(sockaddr*, socklen_t*)							{ return BAN::Error::from_errno(ENOTSUP); }
 
 		// General API
 		virtual BAN::ErrorOr<size_t> read_impl(off_t, BAN::ByteSpan)		{ return BAN::Error::from_errno(ENOTSUP); }

kernel/include/kernel/Networking/NetworkManager.h

@@ -25,6 +25,7 @@ namespace Kernel
 		BAN::Vector<BAN::RefPtr<NetworkInterface>>& interfaces() { return m_interfaces; }
 
 		BAN::ErrorOr<BAN::RefPtr<Socket>> create_socket(Socket::Domain, Socket::Type, mode_t, uid_t, gid_t);
+		BAN::ErrorOr<void> connect_sockets(Socket::Domain, BAN::RefPtr<Socket>, BAN::RefPtr<Socket>);
 
 		void on_receive(NetworkInterface&, BAN::ConstByteSpan);
 

kernel/include/kernel/Networking/NetworkSocket.h

@@ -42,6 +42,7 @@ namespace Kernel
 
 		virtual BAN::ErrorOr<long> ioctl_impl(int request, void* arg) override;
 		virtual BAN::ErrorOr<void> getsockname_impl(sockaddr*, socklen_t*) override;
+		virtual BAN::ErrorOr<void> getpeername_impl(sockaddr*, socklen_t*) override = 0;
 
 	protected:
 		NetworkLayer&		m_network_layer;

kernel/include/kernel/Networking/TCPSocket.h

@@ -61,6 +61,7 @@ namespace Kernel
 		virtual BAN::ErrorOr<void> bind_impl(const sockaddr*, socklen_t) override;
 		virtual BAN::ErrorOr<size_t> sendto_impl(BAN::ConstByteSpan, const sockaddr*, socklen_t) override;
 		virtual BAN::ErrorOr<size_t> recvfrom_impl(BAN::ByteSpan, sockaddr*, socklen_t*) override;
+		virtual BAN::ErrorOr<void> getpeername_impl(sockaddr*, socklen_t*) override;
 
 		virtual void receive_packet(BAN::ConstByteSpan, const sockaddr* sender, socklen_t sender_len) override;
 

kernel/include/kernel/Networking/UDPSocket.h

@@ -36,6 +36,7 @@ namespace Kernel
 		virtual BAN::ErrorOr<void> bind_impl(const sockaddr* address, socklen_t address_len) override;
 		virtual BAN::ErrorOr<size_t> sendto_impl(BAN::ConstByteSpan message, const sockaddr* address, socklen_t address_len) override;
 		virtual BAN::ErrorOr<size_t> recvfrom_impl(BAN::ByteSpan buffer, sockaddr* address, socklen_t* address_len) override;
+		virtual BAN::ErrorOr<void> getpeername_impl(sockaddr*, socklen_t*) override { return BAN::Error::from_errno(ENOTCONN); }
 
 		virtual bool can_read_impl() const override { return !m_packets.empty(); }
 		virtual bool can_write_impl() const override { return true; }

kernel/include/kernel/Networking/UNIX/Socket.h

@@ -25,6 +25,7 @@ namespace Kernel
 		virtual BAN::ErrorOr<void> bind_impl(const sockaddr*, socklen_t) override;
 		virtual BAN::ErrorOr<size_t> sendto_impl(BAN::ConstByteSpan, const sockaddr*, socklen_t) override;
 		virtual BAN::ErrorOr<size_t> recvfrom_impl(BAN::ByteSpan, sockaddr*, socklen_t*) override;
+		virtual BAN::ErrorOr<void> getpeername_impl(sockaddr*, socklen_t*) override;
 
 		virtual bool can_read_impl() const override;
 		virtual bool can_write_impl() const override;

kernel/include/kernel/Process.h

@@ -119,6 +119,7 @@ namespace Kernel
 
 		BAN::ErrorOr<long> sys_socket(int domain, int type, int protocol);
 		BAN::ErrorOr<long> sys_getsockname(int socket, sockaddr* address, socklen_t* address_len);
+		BAN::ErrorOr<long> sys_getpeername(int socket, sockaddr* address, socklen_t* address_len);
 		BAN::ErrorOr<long> sys_getsockopt(int socket, int level, int option_name, void* option_value, socklen_t* option_len);
 		BAN::ErrorOr<long> sys_setsockopt(int socket, int level, int option_name, const void* option_value, socklen_t option_len);
 

kernel/kernel/FS/Inode.cpp

@@ -186,6 +186,14 @@ namespace Kernel
 		return getsockname_impl(address, address_len);
 	}
 
+	BAN::ErrorOr<void> Inode::getpeername(sockaddr* address, socklen_t* address_len)
+	{
+		LockGuard _(m_mutex);
+		if (!mode().ifsock())
+			return BAN::Error::from_errno(ENOTSOCK);
+		return getpeername_impl(address, address_len);
+	}
+
 	BAN::ErrorOr<size_t> Inode::read(off_t offset, BAN::ByteSpan buffer)
 	{
 		LockGuard _(m_mutex);

kernel/kernel/Networking/TCPSocket.cpp

@@ -256,6 +256,17 @@ namespace Kernel
 		return to_send;
 	}
 
+	BAN::ErrorOr<void> TCPSocket::getpeername_impl(sockaddr* address, socklen_t* address_len)
+	{
+		if (!m_has_connected && m_state != State::Established)
+			return BAN::Error::from_errno(ENOTCONN);
+		ASSERT(m_connection_info.has_value());
+		const size_t to_copy = BAN::Math::min(m_connection_info->address_len, *address_len);
+		memcpy(address, &m_connection_info->address, to_copy);
+		*address_len = to_copy;
+		return {};
+	}
+
 	bool TCPSocket::can_read_impl() const
 	{
 		if (m_has_connected && !m_has_sent_zero && m_state != State::Established && m_state != State::Listen)

kernel/kernel/Networking/UNIX/Socket.cpp

@@ -412,4 +412,33 @@ namespace Kernel
 		return nread;
 	}
 
+	BAN::ErrorOr<void> UnixDomainSocket::getpeername_impl(sockaddr* address, socklen_t* address_len)
+	{
+		if (!m_info.has<ConnectionInfo>())
+			return BAN::Error::from_errno(ENOTCONN);
+		auto connection = m_info.get<ConnectionInfo>().connection.lock();
+		if (!connection)
+			return BAN::Error::from_errno(ENOTCONN);
+
+		sockaddr_un sa_un;
+		sa_un.sun_family = AF_UNIX;
+		sa_un.sun_path[0] = 0;
+
+		{
+			SpinLockGuard _(s_bound_socket_lock);
+			for (auto& [path, socket] : s_bound_sockets)
+			{
+				if (socket.lock() != connection)
+					continue;
+				strcpy(sa_un.sun_path, path.data());
+				break;
+			}
+		}
+
+		const size_t to_copy = BAN::Math::min<socklen_t>(sizeof(sockaddr_un), *address_len);
+		memcpy(address, &sa_un, to_copy);
+		*address_len = to_copy;
+		return {};
+	}
+
 }

kernel/kernel/Process.cpp

@@ -1284,6 +1284,20 @@ namespace Kernel
 		return 0;
 	}
 
+	BAN::ErrorOr<long> Process::sys_getpeername(int socket, sockaddr* address, socklen_t* address_len)
+	{
+		LockGuard _(m_process_lock);
+		TRY(validate_pointer_access(address_len, sizeof(address_len), true));
+		TRY(validate_pointer_access(address, *address_len, true));
+
+		auto inode = TRY(m_open_file_descriptors.inode_of(socket));
+		if (!inode->mode().ifsock())
+			return BAN::Error::from_errno(ENOTSOCK);
+
+		TRY(inode->getpeername(address, address_len));
+		return 0;
+	}
+
 	BAN::ErrorOr<long> Process::sys_getsockopt(int socket, int level, int option_name, void* option_value, socklen_t* option_len)
 	{
 		LockGuard _(m_process_lock);

userspace/libraries/LibC/include/sys/syscall.h

@@ -78,6 +78,7 @@ __BEGIN_DECLS
 	O(SYS_SMO_MAP,			smo_map)		\
 	O(SYS_ISATTY,			isatty)			\
 	O(SYS_GETSOCKNAME,		getsockname)	\
+	O(SYS_GETPEERNAME,		getpeername)	\
 	O(SYS_GETSOCKOPT,		getsockopt)		\
 	O(SYS_SETSOCKOPT,		setsockopt)		\
 	O(SYS_REALPATH,			realpath)		\

userspace/libraries/LibC/sys/socket.cpp

@@ -73,6 +73,11 @@ int getsockname(int socket, struct sockaddr* __restrict address, socklen_t* __re
 	return syscall(SYS_GETSOCKNAME, socket, address, address_len);
 }
 
+int getpeername(int socket, struct sockaddr* __restrict address, socklen_t* __restrict address_len)
+{
+	return syscall(SYS_GETPEERNAME, socket, address, address_len);
+}
+
 int getsockopt(int socket, int level, int option_name, void* __restrict option_value, socklen_t* __restrict option_len)
 {
 	return syscall(SYS_GETSOCKOPT, socket, level, option_name, option_value, option_len);
@@ -87,11 +92,6 @@ int setsockopt(int socket, int level, int option_name, const void* option_value,
 
 #include <BAN/Assert.h>
 
-int getpeername(int, struct sockaddr* __restrict, socklen_t* __restrict)
-{
-	ASSERT_NOT_REACHED();
-}
-
 int shutdown(int, int)
 {
 	ASSERT_NOT_REACHED();