iscsi-perf: Use gettimeofday if clock_gettime is unavailable

clock_gettime doesn't existing on OS X
(http://stackoverflow.com/questions/5167269/clock-gettime-alternative-in-mac-os-x
) so add an autoconf test to check if the platform has it and fall back
on gettimeofday if not.

Signed-off-by: Sitsofe Wheeler <sitsofe@yahoo.com>

configure.ac

@@ -128,6 +128,9 @@ AC_CHECK_MEMBER([struct CU_SuiteInfo.pSetUpFunc],
 #include <CUnit/TestDB.h>
 ]])
 
+AC_SEARCH_LIBS(clock_gettime, rt, [
+	       AC_DEFINE([HAVE_CLOCK_GETTIME],1,[Define if clock_gettime is available])])
+
 
 AC_CONFIG_FILES([Makefile]
 		[lib/Makefile]

utils/Makefile.am

@@ -1,6 +1,6 @@
-AM_CPPFLAGS=-I../include "-D_U_=__attribute__((unused))" \
+AM_CPPFLAGS = -I../include "-D_U_=__attribute__((unused))" \
 	"-D_R_(A,B)=__attribute__((format(printf,A,B)))"
-AM_CFLAGS=$(WARN_CFLAGS) -lrt
+AM_CFLAGS = $(WARN_CFLAGS)
 LDADD = ../lib/libiscsi.la
 
 bin_PROGRAMS = iscsi-inq iscsi-ls iscsi-perf iscsi-readcapacity16 \

utils/iscsi-perf.c

@@ -27,6 +27,10 @@
 #include "iscsi.h"
 #include "scsi-lowlevel.h"
 
+#ifndef HAVE_CLOCK_GETTIME
+#include <sys/time.h>
+#endif
+
 #define VERSION "0.1"
 
 const char *initiator = "iqn.2010-11.libiscsi:iscsi-perf";
@@ -55,12 +59,23 @@ struct client {
 };
 
 u_int64_t get_clock_ns(void) {
-	struct timespec tp;
+	int res;
-	if (clock_gettime (CLOCK_MONOTONIC, &tp) == -1) {
+	u_int64_t ns;
-		fprintf(stderr,"could not get clock monotonic\n");
+
+#ifdef HAVE_CLOCK_GETTIME
+	struct timespec ts;
+	res = clock_gettime (CLOCK_MONOTONIC, &tp);
+	ns = ts.tv_sec * 1000000000 + ts.tv_nsec;
+#else
+	struct timeval tv;
+	res = gettimeofday(&tv, NULL);
+	ns = tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
+#endif
+	if (res == -1) {
+		fprintf(stderr,"could not get requested clock\n");
 		exit(10);
 	}
-	return tp.tv_sec*1000000000+tp.tv_nsec;
+	return ns;
 }
 
 void fill_read_queue(struct client *client);