Make timeouts based on CPU time.

diff --git a/src/utils/Makefile b/src/utils/Makefile
new file mode 100644 (file)
index 0000000..9eca3ba
--- /dev/null
+++ b/src/utils/Makefile
@@ -0,0 +1,7 @@
+all: setitimer-helper
+
+LDFLAGS = -lm
+setitimer-helper: setitimer-helper.o
+
+clean: 
+       rm -f *.o setitimer-helper

diff --git a/src/utils/README b/src/utils/README
new file mode 100644 (file)
index 0000000..004478f
--- /dev/null
+++ b/src/utils/README
@@ -0,0 +1,6 @@
+If your version of Perl predates 5.8.0, then you will need to compile
+setitimer-helper (with `make') and install it in PATH, if you want the
+"pintos" script's timeout support (with -T) to properly limit the
+child's CPU time.  Otherwise, it is unneeded.
+
+- Ben

diff --git a/src/utils/pintos b/src/utils/pintos
index f99396841aa65f3873a8cf11145637ae1d7ff489..83954bb951fdabf2a8e7c019e6344fac92bbb7ac 100755 (executable)
--- a/src/utils/pintos
+++ b/src/utils/pintos
@@ -7,6 +7,7 @@ use File::Temp 'tempfile';
 use Getopt::Long qw(:config bundling);
 
 # Command-line options.
+our ($start_time) = time ();
 our ($sim);                    # Simulator: bochs, qemu, or gsx.
 our ($debug) = "none";         # Debugger: none, monitor, or gdb.
 our ($mem) = 4;                        # Physical RAM in MB.
@@ -111,7 +112,8 @@ Display options: (default is both VGA and serial)
 Timing options: (Bochs only)
   -j SEED                  Randomize timer interrupts
   -r, --realtime           Use realistic, not reproducible, timings
-  -T, --timeout=N          Time out and kill Pintos after N seconds
+  -T, --timeout=N          Kill Pintos after N seconds CPU time or N*load_avg
+                           seconds wall-clock time (whichever comes first)
 Configuration options:
   -m, --mem=N              Give Pintos N MB physical RAM (default: 4)
 File system commands (for `run' command):
@@ -660,16 +662,22 @@ sub xsystem {
        die "fork: $!\n";
     } elsif (!$pid) {
        # Running in child process.
-       exec (@_);
-       exit (1);
+       exec_setitimer (@_);
     } else {
        # Running in parent process.
        local $SIG{ALRM} = sub { timeout ($pid); };
        local $SIG{INT} = sub { relay_signal ($pid, "INT"); };
        local $SIG{TERM} = sub { relay_signal ($pid, "TERM"); };
-       alarm ($timeout) if defined ($timeout);
+       alarm ($timeout * get_load_average () + 1) if defined ($timeout);
        waitpid ($pid, 0);
        alarm (0);
+
+       if (WIFSIGNALED ($?) && WTERMSIG ($?) == SIGVTALRM ()) {
+           seek (STDOUT, 0, 2);
+           print "\nTIMEOUT after $timeout seconds of host CPU time\n";
+           exit 0;
+       }
+
        return $?;
     }
 }
@@ -695,8 +703,45 @@ sub timeout {
     waitpid ($pid, 0);
     seek (STDOUT, 0, 2);
     my ($load_avg) = `uptime` =~ /(load average:.*)$/i;
-    print "\nTIMEOUT after $timeout seconds";
+    print "\nTIMEOUT after ", time () - $start_time,
+      " seconds of wall-clock time";
     print  " - $load_avg" if defined $load_avg;
     print "\n";
     exit 0;
 }
+
+# Returns the system load average over the last minute.
+# If the load average is less than 1.0 or cannot be determined, returns 1.0.
+sub get_load_average {
+    my ($avg) = `uptime` =~ /load average:\s*([^,]+),/;
+    return $avg >= 1.0 ? $avg : 1.0;
+}
+
+# Calls setitimer to set a timeout, then execs what was passed to us.
+sub exec_setitimer {
+    if (defined $timeout) {
+       if ($\16 ge 5.8.0) {
+           eval "
+              use Time::HiRes qw(setitimer ITIMER_VIRTUAL);
+              setitimer (ITIMER_VIRTUAL, $timeout, 0);
+            ";
+       } else {
+           { exec ("setitimer-helper", $timeout, @_); };
+           exit 1 if !$!{ENOENT};
+           print STDERR "warning: setitimer-helper is not installed, so ",
+             "CPU time limit will not be enforced\n";
+       }
+    }
+    exec (@_);
+    exit (1);
+}
+
+sub SIGVTALRM {
+    use Config;
+    my $i = 0;
+    foreach my $name (split(' ', $Config{sig_name})) {
+       return $i if $name eq 'VTALRM';
+       $i++;
+    }
+    return 0;
+}

diff --git a/src/utils/setitimer-helper.c b/src/utils/setitimer-helper.c
new file mode 100644 (file)
index 0000000..772d736
--- /dev/null
+++ b/src/utils/setitimer-helper.c
@@ -0,0 +1,49 @@
+#include <errno.h>
+#include <limits.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/time.h>
+#include <unistd.h>
+
+int
+main (int argc, char *argv[]) 
+{
+  const char *program_name = argv[0];
+  double timeout;
+
+  if (argc < 3)
+    {
+      fprintf (stderr,
+               "setitimer-helper: runs a program with a virtual CPU limit\n"
+               "usage: %s TIMEOUT PROGRAM [ARG...]\n"
+               "  where TIMEOUT is the virtual CPU limit, in seconds,\n"
+               "    and remaining arguments specify the program to run\n"
+               "    and its argument.\n",
+               program_name);
+      return EXIT_FAILURE;
+    }
+
+  timeout = strtod (argv[1], NULL);
+  if (timeout >= 0.0 && timeout < LONG_MAX)
+    {
+      struct itimerval it;
+
+      it.it_interval.tv_sec = 0;
+      it.it_interval.tv_usec = 0;
+      it.it_value.tv_sec = timeout;
+      it.it_value.tv_usec = (timeout - floor (timeout)) * 1000000;
+      if (setitimer (ITIMER_VIRTUAL, &it, NULL) < 0)
+        fprintf (stderr, "%s: setitimer: %s\n",
+                 program_name, strerror (errno));
+    }
+  else
+    fprintf (stderr, "%s: invalid timeout value \"%s\"\n",
+             program_name, argv[1]);
+  
+  execvp (argv[2], &argv[2]);
+  fprintf (stderr, "%s: couldn't exec \"%s\": %s\n",
+           program_name, argv[2], strerror (errno));
+  return EXIT_FAILURE;
+}