diff --git a/src/syscalls/mod.rs b/src/syscalls/mod.rs
index 8674e1602f..f51636885b 100644
--- a/src/syscalls/mod.rs
+++ b/src/syscalls/mod.rs
@@ -489,7 +489,7 @@ pub struct Dirent64 {
 	/// File type
 	pub d_type: u8,
 	/// Filename (null-terminated)
-	pub d_name: PhantomData<u8>,
+	pub d_name: PhantomData<c_char>,
 }
 
 #[hermit_macro::system]
diff --git a/src/syscalls/socket.rs b/src/syscalls/socket.rs
index 1c93909fdc..c020bdecc3 100644
--- a/src/syscalls/socket.rs
+++ b/src/syscalls/socket.rs
@@ -1,7 +1,7 @@
 #![allow(dead_code)]
 #![allow(nonstandard_style)]
 use alloc::sync::Arc;
-use core::ffi::c_void;
+use core::ffi::{c_char, c_void};
 use core::mem::size_of;
 use core::ops::DerefMut;
 
@@ -83,7 +83,7 @@ pub struct in6_addr {
 pub struct sockaddr {
 	pub sa_len: u8,
 	pub sa_family: sa_family_t,
-	pub sa_data: [u8; 14],
+	pub sa_data: [c_char; 14],
 }
 
 #[repr(C)]
@@ -93,7 +93,7 @@ pub struct sockaddr_in {
 	pub sin_family: sa_family_t,
 	pub sin_port: in_port_t,
 	pub sin_addr: in_addr,
-	pub sin_zero: [u8; 8],
+	pub sin_zero: [c_char; 8],
 }
 
 #[cfg(all(any(feature = "tcp", feature = "udp"), not(feature = "newlib")))]
@@ -239,7 +239,7 @@ pub struct addrinfo {
 	pub ai_socktype: i32,
 	pub ai_protocol: i32,
 	pub ai_addrlen: socklen_t,
-	pub ai_canonname: *mut u8,
+	pub ai_canonname: *mut c_char,
 	pub ai_addr: *mut sockaddr,
 	pub ai_next: *mut addrinfo,
 }
@@ -571,8 +571,8 @@ pub unsafe extern "C" fn sys_freeaddrinfo(_ai: *mut addrinfo) {}
 
 #[hermit_macro::system]
 pub unsafe extern "C" fn sys_getaddrinfo(
-	_nodename: *const u8,
-	_servname: *const u8,
+	_nodename: *const c_char,
+	_servname: *const c_char,
 	_hints: *const addrinfo,
 	_res: *mut *mut addrinfo,
 ) -> i32 {
diff --git a/src/syscalls/timer.rs b/src/syscalls/timer.rs
index cbcd1f5c00..95d5d2ecf7 100644
--- a/src/syscalls/timer.rs
+++ b/src/syscalls/timer.rs
@@ -3,10 +3,13 @@ use crate::errno::*;
 use crate::syscalls::usleep;
 use crate::time::{itimerval, timespec, timeval};
 
-pub(crate) const CLOCK_REALTIME: u64 = 1;
-pub(crate) const CLOCK_PROCESS_CPUTIME_ID: u64 = 2;
-pub(crate) const CLOCK_THREAD_CPUTIME_ID: u64 = 3;
-pub(crate) const CLOCK_MONOTONIC: u64 = 4;
+#[allow(non_camel_case_types)]
+pub type clockid_t = i32;
+
+pub(crate) const CLOCK_REALTIME: clockid_t = 1;
+pub(crate) const CLOCK_PROCESS_CPUTIME_ID: clockid_t = 2;
+pub(crate) const CLOCK_THREAD_CPUTIME_ID: clockid_t = 3;
+pub(crate) const CLOCK_MONOTONIC: clockid_t = 4;
 pub(crate) const TIMER_ABSTIME: i32 = 4;
 
 /// Finds the resolution (or precision) of a clock.
@@ -20,7 +23,7 @@ pub(crate) const TIMER_ABSTIME: i32 = 4;
 /// - `CLOCK_THREAD_CPUTIME_ID`
 /// - `CLOCK_MONOTONIC`
 #[hermit_macro::system]
-pub unsafe extern "C" fn sys_clock_getres(clock_id: u64, res: *mut timespec) -> i32 {
+pub unsafe extern "C" fn sys_clock_getres(clock_id: clockid_t, res: *mut timespec) -> i32 {
 	assert!(
 		!res.is_null(),
 		"sys_clock_getres called with a zero res parameter"
@@ -49,7 +52,7 @@ pub unsafe extern "C" fn sys_clock_getres(clock_id: u64, res: *mut timespec) ->
 /// - `CLOCK_REALTIME`
 /// - `CLOCK_MONOTONIC`
 #[hermit_macro::system]
-pub unsafe extern "C" fn sys_clock_gettime(clock_id: u64, tp: *mut timespec) -> i32 {
+pub unsafe extern "C" fn sys_clock_gettime(clock_id: clockid_t, tp: *mut timespec) -> i32 {
 	assert!(
 		!tp.is_null(),
 		"sys_clock_gettime called with a zero tp parameter"
@@ -86,7 +89,7 @@ pub unsafe extern "C" fn sys_clock_gettime(clock_id: u64, tp: *mut timespec) ->
 /// - `CLOCK_MONOTONIC`
 #[hermit_macro::system]
 pub unsafe extern "C" fn sys_clock_nanosleep(
-	clock_id: u64,
+	clock_id: clockid_t,
 	flags: i32,
 	rqtp: *const timespec,
 	_rmtp: *mut timespec,
@@ -122,7 +125,7 @@ pub unsafe extern "C" fn sys_clock_nanosleep(
 }
 
 #[hermit_macro::system]
-pub unsafe extern "C" fn sys_clock_settime(_clock_id: u64, _tp: *const timespec) -> i32 {
+pub unsafe extern "C" fn sys_clock_settime(_clock_id: clockid_t, _tp: *const timespec) -> i32 {
 	// We don't support setting any clocks yet.
 	debug!("sys_clock_settime is unimplemented, returning -EINVAL");
 	-EINVAL