From 9476dd8c6041193efdbe572275caff6dfaa5dbf7 Mon Sep 17 00:00:00 2001
From: Claudiu Gheorghe <claudiugh@claudiugh-laptop.(none)>
Date: Fri, 9 Apr 2010 18:16:18 +0300
Subject: [PATCH] Larger granularity on setting the time limit: microseconds

---
 testing/pa/dummy/c.timeout    |  2 +-
 testing/pa/dummy/java.timeout |  2 +-
 testing/pa/tracker.c          | 83 +++++++++++++++++++++--------------
 3 files changed, 53 insertions(+), 34 deletions(-)

diff --git a/testing/pa/dummy/c.timeout b/testing/pa/dummy/c.timeout
index 0cfbf08..95e3ba8 100644
--- a/testing/pa/dummy/c.timeout
+++ b/testing/pa/dummy/c.timeout
@@ -1 +1 @@
-2
+2.5
diff --git a/testing/pa/dummy/java.timeout b/testing/pa/dummy/java.timeout
index 0cfbf08..95e3ba8 100644
--- a/testing/pa/dummy/java.timeout
+++ b/testing/pa/dummy/java.timeout
@@ -1 +1 @@
-2
+2.5
diff --git a/testing/pa/tracker.c b/testing/pa/tracker.c
index 72b30af..0327af9 100644
--- a/testing/pa/tracker.c
+++ b/testing/pa/tracker.c
@@ -7,7 +7,7 @@
  * limit on CPU execution time 
  * 
  * Arguments: 
- * argv[1]: timeout - currently in seconds 
+ * argv[1]: timeout - float value in seconds 
  * argv[2]: input filename 
  * argv[3]: output filename 
  */
@@ -18,6 +18,7 @@
 #include <unistd.h> 
 #include <errno.h>
 #include <fcntl.h>
+#include <math.h>
 #include <sys/time.h> 
 #include <sys/resource.h>
 #include <sys/types.h> 
@@ -26,7 +27,10 @@
 #define MAKEFILE "Makefile"
 #define MAKEFILE_TARGET "run"
 
-void setup_job(int timeout, char *in, char *out) {
+#define UERR 1000
+#define UFACT 1000000
+
+int setup_job(int timeout, char *in, char *out) {
     struct rlimit limit;
     
     /* set the processor time limit */
@@ -37,26 +41,27 @@ void setup_job(int timeout, char *in, char *out) {
     /* redirect input and output */
     int fd_in = open(in, O_RDONLY); 
     if (fd_in < 0) {
-	fprintf(stderr, "Error opening job input file `%s`: %s\n", in, strerror(errno)); 
-	exit(EXIT_FAILURE); 
+        fprintf(stderr, "Error opening job input file `%s`: %s\n", in, strerror(errno)); 
+        return 1; 
     }
 
     if (dup2(fd_in, STDIN_FILENO) < 0) {
-	fprintf(stderr, "Error duplicating input fd: %s\n", strerror(errno)); 
-	exit(EXIT_FAILURE); 
+        fprintf(stderr, "Error duplicating input fd: %s\n", strerror(errno)); 
+        return 1; 
     }
     
     int fd_out = open(out, O_WRONLY | O_CREAT | O_TRUNC, 0666); 
     if (fd_out < 0) {
-	fprintf(stderr, "Error opening job output file `%s`: %s\n", out, strerror(errno)); 
-	exit(EXIT_FAILURE); 
+        fprintf(stderr, "Error opening job output file `%s`: %s\n", out, strerror(errno)); 
+        return 1; 
     }
 
     if (dup2(fd_out, STDOUT_FILENO) < 0) {
-	fprintf(stderr, "Error duplicating output fd: %s\n", strerror(errno)); 
-	exit(EXIT_FAILURE); 
+        fprintf(stderr, "Error duplicating output fd: %s\n", strerror(errno)); 
+        return 1; 
     }
-
+    
+    return 0; 
 }
 
 int main(int argc, char *argv[], char *const envp[]) {
@@ -65,34 +70,48 @@ int main(int argc, char *argv[], char *const envp[]) {
     char *childargv[] = {"make", "-s", "--no-print-directory", "-f", MAKEFILE, MAKEFILE_TARGET, NULL}; 
     
     if (argc != 4) {
-	fprintf(stderr, "Usage: ./tracker <timeout_seconds> <input_file> <output_file> \n"); 
-	exit(EXIT_FAILURE);
+        fprintf(stderr, "Usage: ./tracker <timeout_seconds> <input_file> <output_file> \n"); 
+        exit(EXIT_FAILURE);
     }
 
-    int timeout = atoi(argv[1]); 
+    float ftimeout;
+    int timeout; 
+    sscanf(argv[1], "%f", &ftimeout); 
+    timeout = (int)ceil(ftimeout); 
 
     child_pid = fork(); 
     if (-1 == child_pid) {
-	fprintf(stderr, "Error in fork(): %s\n", strerror(errno)); 
-	exit(EXIT_FAILURE); 
+        fprintf(stderr, "Error in fork(): %s\n", strerror(errno)); 
+        exit(EXIT_FAILURE); 
     } else if (0 == child_pid) {
-	setup_job(timeout, argv[2], argv[3]); 
-	execve("/usr/bin/make", childargv, envp);
-	/* should not be here */
-	fprintf(stderr, "Error in execve(): %s\n", strerror(errno)); 
-	exit(EXIT_FAILURE); 
+        if (setup_job(timeout, argv[2], argv[3])) {
+            exit(EXIT_FAILURE); 
+        }
+        execve("/usr/bin/make", childargv, envp);
+        /* should not be here */
+        fprintf(stderr, "Error in execve(): %s\n", strerror(errno)); 
+        exit(EXIT_FAILURE); 
     } else { 
-	struct rusage accounting; 
-	w = wait4(child_pid, &status, 0, &accounting); 
-	if (WEXITSTATUS(status)) {
-	    /* we got an error */
-	    return WEXITSTATUS(status); 
-	} else {
-	    /* print some stats */
-	    fprintf(stdout, "time: %d.%d seconds\n", 
-		    (int)accounting.ru_utime.tv_sec + (int)accounting.ru_stime.tv_sec,
-		    (int)accounting.ru_utime.tv_usec + (int)accounting.ru_stime.tv_usec); 
-	}
+        struct rusage accounting; 
+        w = wait4(child_pid, &status, 0, &accounting); 
+        if (WEXITSTATUS(status)) {
+            /* we got an error */
+            return WEXITSTATUS(status); 
+        } else {
+            /* print some stats */
+            int seconds = (int)accounting.ru_utime.tv_sec + (int)accounting.ru_stime.tv_sec; 
+            int useconds = (int)accounting.ru_utime.tv_usec + (int)accounting.ru_stime.tv_usec;
+            if (seconds == timeout - 1) {
+                int utimeout = (int)((ftimeout - (float)(timeout - 1)) * UFACT); 
+                if (useconds - utimeout > UERR) {
+                    fprintf(stderr, "CPU time limit exceeded\n");
+                    return 1; 
+                }
+            }
+            /* success */
+            float ftime = (float)seconds + (float)useconds / UFACT; 
+            fprintf(stdout, "time: %f seconds\n", ftime); 
+        }
     }
     
     return 0;