Kernel: Keep track of boot time

kernel/include/utils/Time.h

@@ -0,0 +1,8 @@
+#pragma once
+#include <stdint.h>
+
+int make_yday(int year, int month);
+
+uint64_t broken_down_to_unix(uint64_t year, uint64_t yday, uint64_t hour, uint64_t min, uint64_t sec);
+
+uint64_t unix_boottime(uint8_t boottime[8]);

kernel/src/init/Init.cpp

@@ -17,6 +17,7 @@
 #include "render/TextRenderer.h"
 #include "std/assert.h"
 #include "std/string.h"
+#include "utils/Time.h"
 
 extern BOOTBOOT bootboot;
 extern "C" char environment[4096];
@@ -36,6 +37,7 @@ void Init::disable_smp()
 }
 
 extern "C" void asm_enable_sse();
+extern void clock_init();
 
 void Init::early_init()
 {
@@ -55,6 +57,8 @@ void Init::early_init()
     }
     else if (!strstr(environment, "verbose=1")) { KernelLog::toggle_log_level(LogLevel::DEBUG); }
 
+    clock_init();
+
     InitRD::init();
 
     Mersenne::init();

kernel/src/sys/clock.cpp

@@ -1,9 +1,17 @@
+#include "bootboot.h"
 #include "interrupts/Context.h"
+#include "std/errno.h"
+#include "sys/UserMemory.h"
+#include "thread/PIT.h"
 #include "thread/Scheduler.h"
+#include "utils/Time.h"
+#include <sys/types.h>
 
-void sys_clock(Context* context)
+static uint64_t unix_boot_time;
+
+extern BOOTBOOT bootboot;
+
+void clock_init()
 {
-    Task* current_task = Scheduler::current_task();
+    unix_boot_time = unix_boottime(bootboot.datetime);
-    context->rax = (long)current_task->cpu_time;
-    return;
 }

kernel/src/utils/Time.cpp

@@ -0,0 +1,42 @@
+#define MODULE "time"
+
+#include "utils/Time.h"
+#include "log/Log.h"
+
+int isleap(int year)
+{
+    return year % 4 == 0 && (year % 100 != 0 || year % 400 == 0);
+}
+
+int make_yday(int year, int month)
+{
+    static const short int upto[12] = {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334};
+    int yd;
+
+    yd = upto[month - 1];
+    if (month > 2 && isleap(year)) yd++;
+    return yd;
+}
+
+uint64_t broken_down_to_unix(uint64_t year, uint64_t yday, uint64_t hour, uint64_t min, uint64_t sec)
+{
+    return sec + min * 60 + hour * 3600 + yday * 86400 + (year - 70) * 31536000 + ((year - 69) / 4) * 86400 -
+           ((year - 1) / 100) * 86400 + ((year + 299) / 400) * 86400;
+}
+
+static int bcd_number_to_decimal(int num)
+{
+    return ((num >> 4) * 10) + (num & 0xf);
+}
+
+uint64_t unix_boottime(uint8_t boottime[8])
+{
+    int year = bcd_number_to_decimal(boottime[0]) * 100 + bcd_number_to_decimal(boottime[1]);
+    int month = bcd_number_to_decimal(boottime[2]);
+    int day = bcd_number_to_decimal(boottime[3]);
+    int hour = bcd_number_to_decimal(boottime[4]);
+    int minute = bcd_number_to_decimal(boottime[5]);
+    int second = bcd_number_to_decimal(boottime[6]);
+    kinfoln("UTC boot time: %d-%d-%d %d:%d:%d", year, month, day, hour, minute, second);
+    return broken_down_to_unix(year - 1900, make_yday(year, month) + (day - 1), hour, minute, second);
+}