From: Roy Marples <roy@marples.name>
Date: Mon, 22 Oct 2007 14:32:31 +0000 (+0000)
Subject: Use sysconf to detect if we have a working monotonic clock.
X-Git-Tag: v3.2.3~174
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=33eb264faaa1ca27d1d4ecec8b6c1d98bcb1ece2;p=thirdparty%2Fdhcpcd.git

Use sysconf to detect if we have a working monotonic clock.
---

diff --git a/ChangeLog b/ChangeLog
index d275d479..6d2d69d4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,4 @@
+Use sysconf to detect if we have a working monotonic clock.
 Only request NTP, NIS, etc if we have compiled that feature in.
 dhcpcd --version now shows what compile time options were used.
 
diff --git a/Makefile b/Makefile
index bb1f00fc..611e2f81 100644
--- a/Makefile
+++ b/Makefile
@@ -3,7 +3,7 @@
 # such as the need to link to libresolv and/or librt so please forgive the
 # embedded code :)
 
-VERSION = 3.1.7
+VERSION = 3.1.8_pre1
 CFLAGS += -O2 -pipe
 
 INSTALL ?= install
@@ -32,15 +32,13 @@ _LIBRESOLV != $(_LIBRESOLV_SH)
 LIBRESOLV = $(_LIBRESOLV)$(shell $(_LIBRESOLV_SH))
 
 # Work out if we need -lrt or not
-_LIBRT_SH = printf '\#include <time.h>\nint main (void) { struct timespec ts; return (clock_gettime (CLOCK_MONOTONIC, &ts)); }\n' > .clock_gettime.c; \
+_LIBRT_SH = printf '\#include <time.h>\n\#include <unistd.h>\n\nint main (void) { struct timespec ts;\n\#if defined(_POSIX_MONOTONIC_CLOCK) && defined(CLOCK_MONOTONIC)\nreturn (clock_gettime (CLOCK_MONOTONIC, &ts));\n\#else\nreturn -1;\n\#endif\n}\n' > .clock_gettime.c; \
 	if $(CC) .clock_gettime.c -o .clock_gettime >/dev/null 2>&1; then \
 		echo ""; \
 	elif $(CC) .clock_gettime.c -lrt -o .clock_gettime >/dev/null 2>&1 ; then \
 		echo "-lrt"; \
 	else \
-		echo "Cannot work out how to get clock_gettime to link" >&2; \
-		rm -f .clock_gettime.c .clock_gettime; \
-		exit 1; \
+		echo ""; \
 	fi; \
 	rm -f .clock_gettime.c .clock_gettime
 _LIBRT != $(_LIBRT_SH)
diff --git a/common.c b/common.c
index 1fb50187..45bd8969 100644
--- a/common.c
+++ b/common.c
@@ -105,10 +105,20 @@ void close_fds (void)
  */
 int get_time (struct timeval *tp)
 {
-#ifdef CLOCK_MONOTONIC
+#if defined(_POSIX_MONOTONIC_CLOCK) && defined(CLOCK_MONOTONIC)
 	struct timespec ts;
+	static clockid_t posix_clock;
+	static int posix_clock_set = 0;
+
+	if (! posix_clock_set) {
+		if (sysconf (_SC_MONOTONIC_CLOCK) >= 0)
+			posix_clock = CLOCK_MONOTONIC;
+		else
+			posix_clock = CLOCK_REALTIME;
+		posix_clock_set = 1;
+	}
 
-	if (clock_gettime (CLOCK_MONOTONIC, &ts) == -1) {
+	if (clock_gettime (posix_clock, &ts) == -1) {
 		logger (LOG_ERR, "clock_gettime: %s", strerror (errno));
 		return (-1);
 	}