kernel: misc fixes

kernel-src/include/util.h

@@ -1,6 +1,10 @@
 #ifndef _UTIL_H
 #define _UTIL_H
 
+#include <stdint.h>
+
+#define UTIL_ZEROBUFFERSIZE (1024 * 64)
+
 #define ROUND_DOWN(v, n) ((v) - ((v) % (n)))
 #define ROUND_UP(v, n) ROUND_DOWN((v) + (n) - 1, n)
 
@@ -16,4 +20,6 @@ static inline long min(long x, long y) {
 	return x > y ? y : x;
 }
 
+extern uint8_t util_zerobuffer[];
+
 #endif

kernel-src/lib/util.c

@@ -0,0 +1,3 @@
+#include <util.h>
+
+uint8_t util_zerobuffer[UTIL_ZEROBUFFERSIZE];

kernel-src/sys/syscalls/fcntl.c

@@ -46,11 +46,11 @@ syscallret_t syscall_fcntl(context_t *, int fd, int cmd, uint64_t arg) {
 			break;
 		default:
 			ret.errno = EINVAL;
-			break;
+			goto cleanup;
 	}
-
-	fd_release(file);
-
 	ret.errno = 0;
+
+	cleanup:
+	fd_release(file);
 	return ret;
 }

kernel-src/sys/syscalls/mmap.c

@@ -27,7 +27,7 @@ syscallret_t syscall_mmap(context_t *context, void *hint, size_t len, int prot,
 	__assert((~KNOWN_PROT & prot) == 0);
 
 	// check alignment
-	if (len == 0 || (uintptr_t)hint % PAGE_SIZE || len % PAGE_SIZE) {
+	if (len == 0 || (uintptr_t)hint % PAGE_SIZE) {
 		ret.errno = EINVAL;
 		return ret;
 	}