timediff: return timediff_t from the time diff functions

... to cater for systems with unsigned time_t variables.

- Renamed the functions to curlx_timediff and Curl_timediff_us.

- Added overflow protection for both of them in either direction for
  both 32 bit and 64 bit time_ts

- Reprefixed the curlx_time functions to use Curl_*

Reported-by: Peter Piekarski
Fixes #2004
Closes #2005

3 files changed, 108 insertions, 8 deletions

diff --git a/tests/server/Makefile.inc b/tests/server/Makefile.inc
index c3ea664b6..208aa0fc8 100644
--- a/tests/server/Makefile.inc
+++ b/tests/server/Makefile.inc
@@ -4,14 +4,12 @@ CURLX_SRCS = \
  ../../lib/mprintf.c \
  ../../lib/nonblock.c \
  ../../lib/strtoofft.c \
- ../../lib/timeval.c \
  ../../lib/warnless.c
 
 CURLX_HDRS = \
  ../../lib/curlx.h \
  ../../lib/nonblock.h \
  ../../lib/strtoofft.h \
- ../../lib/timeval.h \
  ../../lib/warnless.h
 
 USEFUL = \
diff --git a/tests/server/util.c b/tests/server/util.c
index 1bbd89a3c..fdbd71f0f 100644
--- a/tests/server/util.c
+++ b/tests/server/util.c
@@ -67,6 +67,8 @@ const struct in6_addr in6addr_any = {{ IN6ADDR_ANY_INIT }};
 #endif /* w32api < 3.6 */
 #endif /* ENABLE_IPV6 && __MINGW32__*/
 
+static struct timeval tvnow(void);
+
 /* This function returns a pointer to STATIC memory. It converts the given
  * binary lump to a hex formatted string usable for output in logs or
  * whatever.
@@ -100,7 +102,7 @@ void logmsg(const char *msg, ...)
   char buffer[2048 + 1];
   FILE *logfp;
   int error;
-  struct curltime tv;
+  struct timeval tv;
   time_t sec;
   struct tm *now;
   char timebuf[20];
@@ -112,7 +114,7 @@ void logmsg(const char *msg, ...)
     return;
   }
 
-  tv = curlx_tvnow();
+  tv = tvnow();
   if(!known_offset) {
     epoch_offset = time(NULL) - tv.tv_sec;
     known_offset = 1;
@@ -213,7 +215,7 @@ int wait_ms(int timeout_ms)
 #ifndef HAVE_POLL_FINE
   struct timeval pending_tv;
 #endif
-  struct curltime initial_tv;
+  struct timeval initial_tv;
   int pending_ms;
   int error;
 #endif
@@ -231,7 +233,7 @@ int wait_ms(int timeout_ms)
   Sleep(timeout_ms);
 #else
   pending_ms = timeout_ms;
-  initial_tv = curlx_tvnow();
+  initial_tv = tvnow();
   do {
 #if defined(HAVE_POLL_FINE)
     r = poll(NULL, 0, pending_ms);
@@ -245,7 +247,7 @@ int wait_ms(int timeout_ms)
     error = errno;
     if(error && (error != EINTR))
       break;
-    pending_ms = timeout_ms - (int)curlx_tvdiff(curlx_tvnow(), initial_tv);
+    pending_ms = timeout_ms - (int)timediff(tvnow(), initial_tv);
     if(pending_ms <= 0)
       break;
   } while(r == -1);
@@ -397,3 +399,102 @@ int strncasecompare(const char *first, const char *second, size_t max)
 
   return raw_toupper(*first) == raw_toupper(*second);
 }
+
+#if defined(WIN32) && !defined(MSDOS)
+
+static struct timeval tvnow(void)
+{
+  /*
+  ** GetTickCount() is available on _all_ Windows versions from W95 up
+  ** to nowadays. Returns milliseconds elapsed since last system boot,
+  ** increases monotonically and wraps once 49.7 days have elapsed.
+  **
+  ** GetTickCount64() is available on Windows version from Windows Vista
+  ** and Windows Server 2008 up to nowadays. The resolution of the
+  ** function is limited to the resolution of the system timer, which
+  ** is typically in the range of 10 milliseconds to 16 milliseconds.
+  */
+  struct timeval now;
+#if defined(_WIN32_WINNT) && (_WIN32_WINNT >= 0x0600)
+  ULONGLONG milliseconds = GetTickCount64();
+#else
+  DWORD milliseconds = GetTickCount();
+#endif
+  now.tv_sec = (long)(milliseconds / 1000);
+  now.tv_usec = (milliseconds % 1000) * 1000;
+  return now;
+}
+
+#elif defined(HAVE_CLOCK_GETTIME_MONOTONIC)
+
+static struct timeval tvnow(void)
+{
+  /*
+  ** clock_gettime() is granted to be increased monotonically when the
+  ** monotonic clock is queried. Time starting point is unspecified, it
+  ** could be the system start-up time, the Epoch, or something else,
+  ** in any case the time starting point does not change once that the
+  ** system has started up.
+  */
+  struct timeval now;
+  struct timespec tsnow;
+  if(0 == clock_gettime(CLOCK_MONOTONIC, &tsnow)) {
+    now.tv_sec = tsnow.tv_sec;
+    now.tv_usec = tsnow.tv_nsec / 1000;
+  }
+  /*
+  ** Even when the configure process has truly detected monotonic clock
+  ** availability, it might happen that it is not actually available at
+  ** run-time. When this occurs simply fallback to other time source.
+  */
+#ifdef HAVE_GETTIMEOFDAY
+  else
+    (void)gettimeofday(&now, NULL);
+#else
+  else {
+    now.tv_sec = (long)time(NULL);
+    now.tv_usec = 0;
+  }
+#endif
+  return now;
+}
+
+#elif defined(HAVE_GETTIMEOFDAY)
+
+static struct timeval tvnow(void)
+{
+  /*
+  ** gettimeofday() is not granted to be increased monotonically, due to
+  ** clock drifting and external source time synchronization it can jump
+  ** forward or backward in time.
+  */
+  struct timeval now;
+  (void)gettimeofday(&now, NULL);
+  return now;
+}
+
+#else
+
+static struct timeval tvnow(void)
+{
+  /*
+  ** time() returns the value of time in seconds since the Epoch.
+  */
+  struct timeval now;
+  now.tv_sec = (long)time(NULL);
+  now.tv_usec = 0;
+  return now;
+}
+
+#endif
+
+long timediff(struct timeval newer, struct timeval older)
+{
+  timediff_t diff = newer.tv_sec-older.tv_sec;
+  if(diff >= (LONG_MAX/1000))
+    return LONG_MAX;
+  else if(diff <= (LONG_MIN/1000))
+    return LONG_MIN;
+  return (long)(newer.tv_sec-older.tv_sec)*1000+
+    (long)(newer.tv_usec-older.tv_usec)/1000;
+}
diff --git a/tests/server/util.h b/tests/server/util.h
index a2a56badd..7b4ec1626 100644
--- a/tests/server/util.h
+++ b/tests/server/util.h
@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2016, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -25,6 +25,7 @@
 
 char *data_to_hex(char *data, size_t len);
 void logmsg(const char *msg, ...);
+long timediff(struct timeval newer, struct timeval older);
 
 #define TEST_DATA_PATH "%s/data/test%ld"