hare

commit 609593785c8dfbdf4b3ecddd674b99635558ab83
parent 3b4410e5e63327b941e2fc0e3a4339ca75009b16
Author: Drew DeVault <sir@cmpwn.com>
Date:   Sun, 31 Jan 2021 12:47:14 -0500

rt: add errno wrapping helpers

We may want to update the syscall wrappers to return tagged unions
instead of raw syscall exits at some point.

Diffstat:
M
rt/+linux/errno.ha
 | 
15
+++++++++++++++
M
rt/+linux/syscalls.ha
 | 
5
+++++

2 files changed, 20 insertions(+), 0 deletions(-)
diff --git a/rt/+linux/errno.ha b/rt/+linux/errno.ha
@@ -1,3 +1,18 @@
+// Represents an error returned from the Linux kernel.
+export type errno = int;
+
+// Given an integer error number, wraps it in an error type.
+export fn wrap_errno(err: int) errno = err: errno;
+
+// Checks the return value from a Linux syscall and, if found to be in error,
+// returns the appropriate error. Otherwise, returns the original value.
+export fn wrap_return(r: size) (errno | size) = {
+	if (r > -4096z) {
+		return (-(r: i64)): int: errno;
+	};
+	return r;
+};
+
 export def EPERM: int		= 1;
 export def ENOENT: int		= 2;
 export def ESRCH: int		= 3;
diff --git a/rt/+linux/syscalls.ha b/rt/+linux/syscalls.ha
@@ -6,6 +6,11 @@ fn syscall4(u64, u64, u64, u64, u64) u64;
 fn syscall5(u64, u64, u64, u64, u64, u64) u64;
 fn syscall6(u64, u64, u64, u64, u64, u64, u64) u64;
 
+export fn close(fd: int) int = syscall1(SYS_close, fd: u64): int;
+
+export fn read(fd: int, buf: *void, count: size) size =
+	syscall3(SYS_read, fd: u64, buf: uintptr: u64, count: u64): size;
+
 export fn write(fd: int, buf: *const void, count: size) size =
 	syscall3(SYS_write, fd: u64, buf: uintptr: u64, count: u64): size;