kernel: implement /dev/bintime

6 files changed, 133 insertions, 0 deletions

diff --git a/src/cmd/tests/kernel/time.c b/src/cmd/tests/kernel/time.c
new file mode 100644
index 0000000..476a90a
--- /dev/null
+++ b/src/cmd/tests/kernel/time.c
@@ -0,0 +1,49 @@
+#include "../tests.h"
+#include <camellia.h>
+
+static void
+test_settime(void) {
+	uint64_t ns = 1000000000;
+	uint64_t base = 1337 * ns;
+	union {
+		uint64_t t;
+		char buf[8];
+	} u;
+
+	hid_t h = camellia_open("/dev/bintime", OPEN_RW);
+
+	/* check if time is reasonable */
+	test(h >= 0);
+	test(_sys_read(h, u.buf, 8, 0) == 8);
+	test(0 < u.t);
+	test(u.t < ns); /* this should've taken less than a second */
+
+	/* try changing the time */
+	u.t = base;
+	test(_sys_write(h, u.buf, 8, 0, 0) == 8);
+
+	/* did we succeed? */
+	u.t = 0;
+	test(_sys_read(h, u.buf, 8, 0) == 8);
+	test(base < u.t);
+	test(u.t < base + ns);
+
+	/* clone the handle */
+	hid_t h2 = _sys_dup(h, 0, DUP_SEARCH | DUP_RDONLY);
+	test(h2 >= 0);
+
+	/* i shouldn't be able to write to it */
+	u.t = 0;
+	test(_sys_write(h2, u.buf, 8, 0, 0) == -EACCES);
+
+	/* but reads should be fine */
+	test(_sys_read(h2, u.buf, 8, 0) == 8);
+	test(base < u.t);
+	test(u.t < base + ns);
+}
+
+void
+r_k_time(void)
+{
+	run_test(test_settime);
+}
diff --git a/src/cmd/tests/tests.c b/src/cmd/tests/tests.c
index 2b7ba01..2b66b43 100644
--- a/src/cmd/tests/tests.c
+++ b/src/cmd/tests/tests.c
@@ -54,6 +54,7 @@ int main(void) {
 		r_k_misc();
 		r_k_path();
 		r_k_threads();
+		r_k_time();
 		r_libc_esemaphore();
 		r_libc_setjmp();
 		r_libc_string();
diff --git a/src/cmd/tests/tests.h b/src/cmd/tests/tests.h
index bbf5309..f562d27 100644
--- a/src/cmd/tests/tests.h
+++ b/src/cmd/tests/tests.h
@@ -13,6 +13,7 @@ void r_k_misc(void);
 void r_k_miscsyscall(void);
 void r_k_path(void);
 void r_k_threads(void);
+void r_k_time(void);
 void r_libc_esemaphore(void);
 void r_libc_setjmp(void);
 void r_libc_string(void);
diff --git a/src/kernel/arch/amd64/boot.c b/src/kernel/arch/amd64/boot.c
index 19f249a..14690a8 100644
--- a/src/kernel/arch/amd64/boot.c
+++ b/src/kernel/arch/amd64/boot.c
@@ -70,6 +70,7 @@ void kmain_early(void *mbi) {
 	serial_init();
 	video_init(vid);
 	pata_init();
+	time_init();
 
 	{
 		struct multiboot_tag_old_acpi *mod;
diff --git a/src/kernel/arch/amd64/driver/driver.h b/src/kernel/arch/amd64/driver/driver.h
index 0c4ecd5..6f862cf 100644
--- a/src/kernel/arch/amd64/driver/driver.h
+++ b/src/kernel/arch/amd64/driver/driver.h
@@ -14,5 +14,6 @@ struct GfxInfo {
 void pata_init(void);
 void ps2_init(void);
 void rtl8139_init(uint32_t bdf);
+void time_init(void);
 void vfs_root_init(void);
 void video_init(GfxInfo);
diff --git a/src/kernel/arch/amd64/driver/time.c b/src/kernel/arch/amd64/driver/time.c
new file mode 100644
index 0000000..8ae6fb2
--- /dev/null
+++ b/src/kernel/arch/amd64/driver/time.c
@@ -0,0 +1,80 @@
+/* This is already sort of deprecated as I introduce it --
+ * it doesn't seem to provide much benefit over _sys_time, which I think I
+ * have to keep anyways, so processes in an empty namespace can still keep
+ * time. */
+#include <camellia/errno.h>
+#include <camellia/fsutil.h>
+#include <kernel/arch/amd64/driver/driver.h>
+#include <kernel/arch/amd64/driver/util.h>
+#include <kernel/malloc.h>
+#include <kernel/panic.h>
+#include <kernel/proc.h>
+#include <kernel/util.h>
+#include <kernel/vfs/mount.h>
+#include <kernel/vfs/request.h>
+#include <shared/mem.h>
+
+typedef struct {
+	uint64_t base;
+} TimeObj;
+
+static long
+handle(VfsReq *req)
+{
+	TimeObj *h;
+	if (req->type == VFSOP_OPEN) {
+		if (reqpathcmp(req, "")) {
+			h = kmalloc(sizeof *h, "dev/time");
+			h->base = uptime_ns();
+			return (uintptr_t)h;
+		} else {
+			return -ENOENT;
+		}
+	}
+	h = (__force void*)req->id;
+
+	if (req->type == VFSOP_CLOSE) {
+		assert(h);
+		kfree(h);
+		return 0;
+	}
+
+	uint64_t now = uptime_ns();
+
+	union {
+		char buf[8];
+		uint64_t t;
+	} u;
+	switch (req->type) {
+	case VFSOP_READ:
+		u.t = now - h->base;
+		return req_readcopy(req, u.buf, sizeof u.buf);
+	case VFSOP_GETSIZE:
+		return 8;
+	case VFSOP_WRITE:
+		if (req->input.len == 8) {
+			assert(!req->input.kern);
+			if (pcpy_from(req->caller, u.buf, req->input.buf, sizeof u.buf) != sizeof(u.buf)) {
+				return -EGENERIC;
+			}
+			h->base = now - u.t;
+			assert(u.t == now - h->base);
+			return 8;
+		}
+		return -EGENERIC;
+	default:
+		return -ENOSYS;
+	}
+}
+
+static void
+accept(VfsReq *req)
+{
+	vfsreq_finish_short(req, handle(req));
+}
+
+void
+time_init(void)
+{
+	vfs_root_register("/dev/bintime", accept);
+}