clock: Use 64-bit integer to measure time duration

To ensure compatibility with platforms where long is a 32-bit
integer, the unsigned long oc_clock_seconds() function has been
replaced with uint64_t oc_clock_seconds_v1(). This change allows
the representation of UNIX Epoch times beyond the year 2038, which
would otherwise be limited by the 32-bit integer size of long.

Fixes coverity issue:
55774: Use of 32-bit time_t

api/unittest/plgdtimetest.cpp

@@ -148,6 +148,7 @@ TEST_F(TestPlgdTime, Seconds)
   oc_clock_time_t start_ts = start / OC_CLOCK_SECOND;
   EXPECT_LE(start_ts, now_ts);
   EXPECT_GT(oc_clock_seconds(), now_ts);
+  EXPECT_GT(oc_clock_seconds_v1(), now_ts);
 }
 
 TEST_F(TestPlgdTime, IsActive)

port/android/clock.c

@@ -56,8 +56,8 @@ oc_clock_time_monotonic(void)
          (oc_clock_time_t)ceil((double)t.tv_nsec / (1.e09 / OC_CLOCK_SECOND));
 }
 
-unsigned long
-oc_clock_seconds(void)
+uint64_t
+oc_clock_seconds_v1(void)
 {
   struct timespec t;
   if (clock_gettime(CLOCK_REALTIME, &t) != -1) {
@@ -66,6 +66,12 @@ oc_clock_seconds(void)
   return 0;
 }
 
+unsigned long
+oc_clock_seconds(void)
+{
+  return (unsigned long)oc_clock_seconds_v1();
+}
+
 void
 oc_clock_wait(oc_clock_time_t t)
 {

port/arduino/adapter/oc_clock.c

@@ -54,10 +54,16 @@ oc_clock_time_monotonic(void)
   return oc_clock_time();
 }
 
+uint64_t
+oc_clock_seconds_v1(void)
+{
+  return (uint64_t)oc_clock_seconds_v1();
+}
+
 unsigned long
 oc_clock_seconds(void)
 {
-  return (unsigned long)secondNow();
+  return (unsigned long)oc_clock_seconds_v1();
 }
 
 void

port/esp32/adapter/src/clock.c

@@ -56,8 +56,8 @@ oc_clock_time_monotonic(void)
     (double)(esp_timer_get_time() / (1.e06 / OC_CLOCK_SECOND)));
 }
 
-unsigned long
-oc_clock_seconds(void)
+uint64_t
+oc_clock_seconds_v1(void)
 {
   struct timespec t;
   if (clock_gettime(CLOCK_REALTIME, &t) != -1) {
@@ -66,6 +66,12 @@ oc_clock_seconds(void)
   return 0;
 }
 
+unsigned long
+oc_clock_seconds(void)
+{
+  return (unsigned long)oc_clock_seconds_v1();
+}
+
 void
 oc_clock_wait(oc_clock_time_t t)
 {

port/linux/clock.c

@@ -56,8 +56,8 @@ oc_clock_time_monotonic(void)
          (oc_clock_time_t)ceil((double)t.tv_nsec / (1.e09 / OC_CLOCK_SECOND));
 }
 
-unsigned long
-oc_clock_seconds(void)
+uint64_t
+oc_clock_seconds_v1(void)
 {
   struct timespec t;
   if (clock_gettime(CLOCK_REALTIME, &t) != -1) {
@@ -66,6 +66,12 @@ oc_clock_seconds(void)
   return 0;
 }
 
+unsigned long
+oc_clock_seconds(void)
+{
+  return (unsigned long)oc_clock_seconds_v1();
+}
+
 void
 oc_clock_wait(oc_clock_time_t t)
 {

port/oc_clock.h

@@ -54,6 +54,8 @@
 
 #include "oc_clock_util.h"
 #include "oc_export.h"
+#include "util/oc_compiler.h"
+
 #include <stdbool.h>
 #include <stdint.h>
 
@@ -121,13 +123,22 @@ oc_clock_time_t oc_clock_time_monotonic(void);
 /**
  * Get the current value of the platform seconds.
  *
- * This could be the number of seconds since startup, or
- * since a standard epoch.
+ * This could be the number of seconds since startup, or since a standard epoch.
  *
  * \return The value.
  */
 OC_API
-unsigned long oc_clock_seconds(void);
+uint64_t oc_clock_seconds_v1(void);
+
+/**
+ * Get the current value of the platform seconds.
+
+ * @deprecated Use oc_clock_seconds_v1 instead because it returns a 64-bit value
+ * on all platforms and thus is safe for years 2038+.
+ */
+OC_API
+unsigned long oc_clock_seconds(void)
+  OC_DEPRECATED("replaced by oc_clock_seconds_v1 in v2.2.5.7");
 
 /**
  * Wait for a given number of ticks.

port/openthread/clock.c

@@ -56,12 +56,17 @@ oc_clock_time_monotonic(void)
   return oc_clock_time();
 }
 
+uint64_t
+oc_clock_seconds_v1(void)
+{
+  uint64_t time = oc_clock_time() / OC_CLOCK_SECOND;
+  return time;
+}
+
 unsigned long
 oc_clock_seconds(void)
 {
-  unsigned long time = oc_clock_time() / OC_CLOCK_SECOND;
-
-  return time;
+  return (unsigned long)oc_clock_seconds_v1();
 }
 
 void

port/windows/clock.c

@@ -121,10 +121,16 @@ oc_clock_time_monotonic(void)
   return whole + part;
 }
 
+uint64_t
+oc_clock_seconds_v1(void)
+{
+  return (uint64_t)time(0);
+}
+
 unsigned long
 oc_clock_seconds(void)
 {
-  return (unsigned long)time(0);
+  return (unsigned long)oc_clock_seconds_v1();
 }
 
 void

port/zephyr/src/clock.c

@@ -41,10 +41,16 @@ oc_clock_time_monotonic(void)
   return oc_clock_time();
 }
 
+uint64_t
+oc_clock_seconds_v1(void)
+{
+  return (oc_clock_time() + OC_CLOCK_SECOND - 1) / OC_CLOCK_SECOND;
+}
+
 unsigned long
 oc_clock_seconds(void)
 {
-  return (oc_clock_time() + OC_CLOCK_SECOND - 1) / OC_CLOCK_SECOND;
+  return (unsigned long)oc_clock_seconds_v1();
 }
 
 void

swig/swig_interfaces/oc_clock.i

@@ -31,8 +31,10 @@ typedef long long oc_clock_time_t;
 %rename(clockTime) oc_clock_time;
 %rename(clockTimeMonotonic) oc_clock_time_monotonic;
 %rename(clockSeconds) oc_clock_seconds;
+%rename(clockSecondsV1) oc_clock_seconds_v1;
 %rename(clockWait) oc_clock_wait;
 
 #define OC_API
+#define OC_DEPRECATED(...)
 #define OC_NONNULL(...)
 %include "port/oc_clock.h"