8234397: add OS uptime information to os::print_os_info output

Reviewed-by: clanger, dholmes, lucy

src/hotspot/os/aix/os_aix.cpp

@@ -1384,6 +1384,8 @@ void os::print_os_info(outputStream* st) {
   st->print_cr("AIX kernel version %u.%u.%u.%u",
                (ver >> 24) & 0xFF, (ver >> 16) & 0xFF, (ver >> 8) & 0xFF, ver & 0xFF);
 
+  os::Posix::print_uptime_info(st);
+
   os::Posix::print_rlimit_info(st);
 
   os::Posix::print_load_average(st);

src/hotspot/os/bsd/os_bsd.cpp

@@ -168,6 +168,22 @@ julong os::Bsd::available_memory() {
   return available;
 }
 
+// for more info see :
+// https://man.openbsd.org/sysctl.2
+void os::Bsd::print_uptime_info(outputStream* st) {
+  struct timeval boottime;
+  size_t len = sizeof(boottime);
+  int mib[2];
+  mib[0] = CTL_KERN;
+  mib[1] = KERN_BOOTTIME;
+
+  if (sysctl(mib, 2, &boottime, &len, NULL, 0) >= 0) {
+    time_t bootsec = boottime.tv_sec;
+    time_t currsec = time(NULL);
+    os::print_dhm(st, "OS uptime:", (long) difftime(currsec, bootsec));
+  }
+}
+
 julong os::physical_memory() {
   return Bsd::physical_memory();
 }
@@ -1569,6 +1585,8 @@ void os::print_os_info(outputStream* st) {
 
   os::Posix::print_uname_info(st);
 
+  os::Bsd::print_uptime_info(st);
+
   os::Posix::print_rlimit_info(st);
 
   os::Posix::print_load_average(st);

src/hotspot/os/bsd/os_bsd.hpp

@@ -155,6 +155,8 @@ class Bsd {
     }
   }
   static int get_node_by_cpu(int cpu_id);
+
+  static void print_uptime_info(outputStream* st);
 };
 
 #endif // OS_BSD_OS_BSD_HPP

src/hotspot/os/linux/os_linux.cpp

@@ -2119,6 +2119,8 @@ void os::print_os_info(outputStream* st) {
 
   os::Posix::print_uname_info(st);
 
+  os::Linux::print_uptime_info(st);
+
   // Print warning if unsafe chroot environment detected
   if (unsafe_chroot_detected) {
     st->print("WARNING!! ");
@@ -2304,6 +2306,15 @@ void os::Linux::print_ld_preload_file(outputStream* st) {
   st->cr();
 }
 
+void os::Linux::print_uptime_info(outputStream* st) {
+  struct sysinfo sinfo;
+  int ret = sysinfo(&sinfo);
+  if (ret == 0) {
+    os::print_dhm(st, "OS uptime:", (long) sinfo.uptime);
+  }
+}
+
+
 void os::Linux::print_container_info(outputStream* st) {
   if (!OSContainer::is_containerized()) {
     return;

src/hotspot/os/linux/os_linux.hpp

@@ -103,6 +103,7 @@ class Linux {
   static void print_libversion_info(outputStream* st);
   static void print_proc_sys_info(outputStream* st);
   static void print_ld_preload_file(outputStream* st);
+  static void print_uptime_info(outputStream* st);
 
  public:
   struct CPUPerfTicks {

src/hotspot/os/posix/os_posix.cpp

@@ -49,6 +49,7 @@
 #include <sys/utsname.h>
 #include <time.h>
 #include <unistd.h>
+#include <utmpx.h>
 
 // Todo: provide a os::get_max_process_id() or similar. Number of processes
 // may have been configured, can be read more accurately from proc fs etc.
@@ -379,6 +380,27 @@ void os::Posix::print_load_average(outputStream* st) {
   st->cr();
 }
 
+// boot/uptime information;
+// unfortunately it does not work on macOS and Linux because the utx chain has no entry
+// for reboot at least on my test machines
+void os::Posix::print_uptime_info(outputStream* st) {
+  int bootsec = -1;
+  int currsec = time(NULL);
+  struct utmpx* ent;
+  setutxent();
+  while ((ent = getutxent())) {
+    if (!strcmp("system boot", ent->ut_line)) {
+      bootsec = ent->ut_tv.tv_sec;
+      break;
+    }
+  }
+
+  if (bootsec != -1) {
+    os::print_dhm(st, "OS uptime:", (long) (currsec-bootsec));
+  }
+}
+
+
 void os::Posix::print_rlimit_info(outputStream* st) {
   st->print("rlimit:");
   struct rlimit rlim;

src/hotspot/os/posix/os_posix.hpp

@@ -41,6 +41,7 @@ protected:
   static void print_uname_info(outputStream* st);
   static void print_libversion_info(outputStream* st);
   static void print_load_average(outputStream* st);
+  static void print_uptime_info(outputStream* st);
 
   // Minimum stack size a thread can be created with (allowing
   // the VM to completely create the thread and enter user code).

src/hotspot/os/solaris/os_solaris.cpp

@@ -1584,6 +1584,8 @@ void os::print_os_info(outputStream* st) {
 
   os::Posix::print_uname_info(st);
 
+  os::Posix::print_uptime_info(st);
+
   os::Solaris::print_libversion_info(st);
 
   os::Posix::print_rlimit_info(st);

src/hotspot/os/windows/os_windows.cpp

@@ -1591,6 +1591,11 @@ void os::print_os_info_brief(outputStream* st) {
   os::print_os_info(st);
 }
 
+void os::win32::print_uptime_info(outputStream* st) {
+  unsigned long long ticks = GetTickCount64();
+  os::print_dhm(st, "OS uptime:", ticks/1000);
+}
+
 void os::print_os_info(outputStream* st) {
 #ifdef ASSERT
   char buffer[1024];
@@ -1604,6 +1609,8 @@ void os::print_os_info(outputStream* st) {
   st->print("OS:");
   os::win32::print_windows_version(st);
 
+  os::win32::print_uptime_info(st);
+
 #ifdef _LP64
   VM_Version::print_platform_virtualization_info(st);
 #endif

src/hotspot/os/windows/os_windows.hpp

@@ -55,6 +55,7 @@ class win32 {
   static bool   _has_exit_bug;
 
   static void print_windows_version(outputStream* st);
+  static void print_uptime_info(outputStream* st);
 
  public:
   // Windows-specific interface:

src/hotspot/share/runtime/os.cpp

@@ -928,6 +928,14 @@ void os::print_hex_dump(outputStream* st, address start, address end, int unitsi
   st->cr();
 }
 
+void os::print_dhm(outputStream* st, const char* startStr, long sec) {
+  long days    = sec/86400;
+  long hours   = (sec/3600) - (days * 24);
+  long minutes = (sec/60) - (days * 1440) - (hours * 60);
+  if (startStr == NULL) startStr = "";
+  st->print_cr("%s %ld days %ld:%02ld hours", startStr, days, hours, minutes);
+}
+
 void os::print_instructions(outputStream* st, address pc, int unitsize) {
   st->print_cr("Instructions: (pc=" PTR_FORMAT ")", p2i(pc));
   print_hex_dump(st, pc - 256, pc + 256, unitsize);

src/hotspot/share/runtime/os.hpp

@@ -632,6 +632,9 @@ class os: AllStatic {
   static void print_date_and_time(outputStream* st, char* buf, size_t buflen);
   static void print_instructions(outputStream* st, address pc, int unitsize);
 
+  // helper for output of seconds in days , hours and months
+  static void print_dhm(outputStream* st, const char* startStr, long sec);
+
   static void print_location(outputStream* st, intptr_t x, bool verbose = false);
   static size_t lasterror(char *buf, size_t len);
   static int get_last_error();