syscalls: implement clock_getres

kernel-src/arch/x86-64/syscall.asm

@@ -102,6 +102,7 @@ extern syscall_yield
 extern syscall_fstatvfs
 extern syscall_fstatvfsat
 extern syscall_getsockopt
+extern syscall_clock_getres
 syscalltab:
 dq syscall_print
 dq syscall_mmap
@@ -206,7 +207,8 @@ dq syscall_yield
 dq syscall_fstatvfs
 dq syscall_fstatvfsat
 dq syscall_getsockopt
-syscallcount equ 103
+dq syscall_clock_getres
+syscallcount equ 104
 section .text
 global arch_syscall_entry
 ; on entry:

kernel-src/arch/x86-64/syscalllog.c

@@ -9,7 +9,7 @@
 void arch_interrupt_disable();
 void arch_interrupt_enable();
 
-#define SYSCALL_COUNT 103
+#define SYSCALL_COUNT 104
 #define LOGSTR(x) arch_e9_puts(x)
 
 static char *name[] = {
@@ -116,6 +116,7 @@ static char *name[] = {
 	"fstatvfs",
 	"fstatvfsat",
 	"getsockopt",
+	"clock_getres",
 };
 
 static char *args[] = {
@@ -222,6 +223,7 @@ static char *args[] = {
 	"fd %d ustat %p", // fstatvfs
 	"dirfd %d path %s ustat %p flags %d", // fstatvfsat
 	"fd %d level %d optname %d optval %p optlen %p", // getsockopt
+	"clockid %d timespec %p", // clock_getres
 };
 
 #endif

kernel-src/sys/syscalls/clockgetres.c

@@ -0,0 +1,34 @@
+#include <kernel/syscalls.h>
+#include <time.h>
+#include <kernel/usercopy.h>
+
+#define CLOCK_REALTIME 0
+#define CLOCK_MONOTONIC 1
+#define CLOCK_BOOTTIME 7
+
+syscallret_t syscall_clock_getres(context_t *, int clockid, timespec_t *res) {
+	syscallret_t ret;
+
+	switch (clockid) {
+		case CLOCK_REALTIME:
+		case CLOCK_MONOTONIC:
+		case CLOCK_BOOTTIME:
+			if (res) {
+				timespec_t ts = {
+					.s = 0,
+					.ns = 1
+				};
+
+				ret.errno = usercopy_touser(res, &ts, sizeof(timespec_t));
+			} else {
+				ret.errno = 0;
+			}
+			break;
+		default:
+			ret.errno = EINVAL;
+			break;
+	}
+
+	ret.ret = ret.errno ? -1 : 0;
+	return ret;
+}