lib: c: implement munmap()

lib/libc/include/sys/mman.h

@@ -41,5 +41,6 @@ extern void *mmap(
 	int flags,
 	int fd,
 	off_t offset);
+extern int munmap(void *addr, size_t length);
 
 #endif

lib/libc/io/unistd/munmap.c

@@ -0,0 +1,34 @@
+#include <errno.h>
+#include <mango/handle.h>
+#include <mango/task.h>
+#include <mango/vm.h>
+#include <rosetta/fs.h>
+#include <stdbool.h>
+#include <sys/mman.h>
+
+int munmap(void *addr, size_t length)
+{
+	kern_status_t status = KERN_OK;
+	kern_handle_t self = KERN_HANDLE_INVALID,
+		      address_space = KERN_HANDLE_INVALID;
+
+	status = task_self(&self);
+	if (status != KERN_OK) {
+		return __set_errno(EPERM);
+	}
+
+	status = task_get_address_space(self, &address_space);
+	kern_handle_close(self);
+	if (status != KERN_OK) {
+		return __set_errno(EPERM);
+	}
+
+	status = address_space_unmap(address_space, (virt_addr_t)addr, length);
+
+	kern_handle_close(address_space);
+	if (status != KERN_OK) {
+		return __set_errno(__errno_from_kern_status(status));
+	}
+
+	return __set_errno(SUCCESS);
+}