From a1c578f34752e20cb24bfd568775efe465980da7 Mon Sep 17 00:00:00 2001
From: "Bjoern B. Brandenburg" <bbb@cs.unc.edu>
Date: Sat, 2 May 2009 21:49:31 -0400
Subject: release: add -w and -f options

---
 bin/release_ts.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 77 insertions(+), 2 deletions(-)

diff --git a/bin/release_ts.c b/bin/release_ts.c
index 4d4c9e8..9740df2 100644
--- a/bin/release_ts.c
+++ b/bin/release_ts.c
@@ -2,24 +2,90 @@
 #include <stdio.h>
 #include <unistd.h>
 
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
 #include "litmus.h"
 
-#define OPTSTR "d:"
+#define OPTSTR "d:wf:"
 #define NS_PER_MS 1000000
 
+#define LITMUS_STATS_FILE "/proc/litmus/stats"
+
 void usage(char *error) {
 	fprintf(stderr,
 		"%s\n"
-		"Usage: release_ts [-d <delay in ms>]\n",
+		"Usage: release_ts [OPTIONS]\n"
+		"\n"
+		"Options: -d  <delay in ms>  (default: 1000ms)\n"
+		"         -w  wait until all tasks are ready for release\n"
+		"             (as determined by /proc/litmus/stats\n"
+		"         -f  <#tasks> wait for #tasks (default: 0)\n"
+		"\n",
 		error);
 	exit(1);
 }
 
+ssize_t read_file(const char* fname, void* buf, size_t maxlen)
+{
+	int fd;
+	ssize_t n = 0;
+	size_t got = 0;
+
+	fd = open(fname, O_RDONLY);
+	if (fd == -1)
+		return -1;
+	
+	while (got < maxlen && (n = read(fd, buf + got, maxlen - got)) > 0)
+		got += n;
+	close(fd);
+	if (n < 0)
+		return -1;
+	else
+		return got;
+}
+
+void wait_until_ready(int expected)
+{
+	int ready = 0, all = 0;
+	char buf[100];
+	int loops = 0;
+	ssize_t len;
+	
+
+	do {
+		if (loops++ > 0)
+			sleep(1);
+		len = read_file(LITMUS_STATS_FILE, buf, sizeof(buf) - 1);
+		if (len < 0) {
+			fprintf(stderr,
+				"(EE) Error while reading '%s': %m.\n"
+				"(EE) Ignoring -w option.\n",
+				LITMUS_STATS_FILE);
+			break;
+		} else {
+			len = sscanf(buf,
+				     "real-time tasks   = %d\n"
+				     "ready for release = %d\n",
+				     &all, &ready);
+			if (len != 2) {
+				fprintf(stderr, 
+					"(EE) Could not parse '%s'.\n"
+					"(EE) Ignoring -w option.\n",
+					LITMUS_STATS_FILE);
+				break;
+			}
+		}
+	} while (expected > ready || ready < all);
+}
 
 int main(int argc, char** argv)
 {
 	int released;
 	lt_t delay = ms2lt(1000);
+	int wait = 0;
+	int expected = 0;
 	int opt;
       
 	while ((opt = getopt(argc, argv, OPTSTR)) != -1) {
@@ -27,6 +93,12 @@ int main(int argc, char** argv)
 		case 'd':
 			delay = ms2lt(atoi(optarg));
 			break;
+		case 'w':
+			wait = 1;
+			break;
+		case 'f':
+			expected = atoi(optarg);
+			break;
 		case ':':
 			usage("Argument missing.");
 			break;
@@ -37,6 +109,9 @@ int main(int argc, char** argv)
 		}
 	}
 
+	if (wait)
+		wait_until_ready(expected);
+
 	released = release_ts(&delay);
 	if (released < 0) {
 		perror("release task system");
-- 
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