liblinux++

commit ecbed962c021579f1bdf8f010da7c9de7dae84f4
parent 0dda04fa914c3932d10a52f3517ed51650aa8f64
Author: Henry Wilson <henry@henryandlizzy.uk>
Date:   Thu,  8 Jan 2026 01:08:23 +0000

add tcp-listen (basic TCP server)

Diffstat:
M
linux.hpp
 | 
33
+++++++++++++++++++++++++++++++++
M
syscalls.h
 | 
20
++++++++++++++++++++
A
tcp-listen.cpp
 | 
18
++++++++++++++++++

3 files changed, 71 insertions(+), 0 deletions(-)
diff --git a/linux.hpp b/linux.hpp
@@ -16,6 +16,7 @@ using intptr_t = int64_t;
 using ino64_t = uint64_t;
 using off64_t = int64_t;
 using time_t = int64_t;
+using socklen_t = uint32_t;
 
 enum {
 	O_RDONLY = 0,
@@ -191,6 +192,38 @@ extern syscall_result<void> unlinkat(file dir, c_str path, unlink_flags flags);
 
 extern syscall_result<void> execve(c_str path, char *const /*_Nullable*/ argv[], char *const /*_Nullable*/ envp[]);
 
+extern syscall_result<file> socket(int domain, int type, int protocol);
+
+struct addr_ref
+{
+	span<char const> fat_ptr;
+};
+
+struct in_addr
+{
+	in_addr(uint16_t port, uint32_t ipv4)
+	: family{2}
+	, data{
+		uint8_t((port & 0xFF00) >> 8),
+		uint8_t((port & 0x00FF) >> 0),
+		uint8_t((ipv4 & 0xFF00'0000) >> 24),
+		uint8_t((ipv4 & 0x00FF'0000) >> 16),
+		uint8_t((ipv4 & 0x0000'FF00) >> 8),
+		uint8_t((ipv4 & 0x0000'00FF) >> 0),
+	}
+	{}
+
+	operator addr_ref() const { return {.fat_ptr = {(char const*)this, sizeof(*this)}}; }
+private:
+	uint16_t family;
+	uint8_t data[14];
+};
+
+extern syscall_result<void> bind(file socket, addr_ref addr);
+extern syscall_result<void> listen(file socket, int backlog);
+extern syscall_result<file> accept(file socket, void* addr_buf, socklen_t* addr_len);
+extern syscall_result<file> dup(file oldfd, file newfd, int flags = 0);
+
 extern "C"
 {
 
diff --git a/syscalls.h b/syscalls.h
@@ -51,3 +51,23 @@ SYS(mmap)
 extern renameat2
 extern_alias _Z9renameat24file5c_strS_S0_12rename_flags
 SYS(renameat2)
+
+extern socket
+extern_alias _Z6socketiii
+SYS(socket)
+
+extern bind
+extern_alias _Z4bind4file8addr_ref
+SYS(bind)
+
+extern listen
+extern_alias _Z6listen4filei
+SYS(listen)
+
+extern accept
+extern_alias _Z6accept4filePvPj
+SYS(accept)
+
+extern dup3
+extern_alias _Z3dup4fileS_i
+SYS(dup3)
diff --git a/tcp-listen.cpp b/tcp-listen.cpp
@@ -0,0 +1,18 @@
+#include "linux.hpp"
+
+int main(int argc, char* argv[], char* envp[])
+{
+	if (argc < 2)
+		return 1;
+	file sock = *socket(2/*AF_INET*/, 1/*SOCK_STREAM*/, 0/*IPPROTO_IP*/);
+	in_addr addr{1337, 0/*IN_ADDR_ANY*/};
+	*bind(sock, addr);
+	*listen(sock, 1);
+	socklen_t addr_len = sizeof(addr);
+	file conn = *accept(sock, &addr, &addr_len);
+	*dup(conn, stdin);
+	*dup(conn, stdout);
+	*close(conn);
+	*close(sock);
+	*execve(argv[1], argv+1, envp);
+}