4 files changed, 200 insertions, 0 deletions

diff --git a/tests/userprog/no-vm/Make.tests b/tests/userprog/no-vm/Make.tests
new file mode 100644
index 0000000..a545e18
--- /dev/null
+++ b/tests/userprog/no-vm/Make.tests
@@ -0,0 +1,8 @@
+# -*- makefile -*-
+
+tests/userprog/no-vm_TESTS = tests/userprog/no-vm/multi-oom
+tests/userprog/no-vm_PROGS = $(tests/userprog/no-vm_TESTS)
+tests/userprog/no-vm/multi-oom_SRC = tests/userprog/no-vm/multi-oom.c   \
+tests/lib.c
+
+tests/userprog/no-vm/multi-oom.output: TIMEOUT = 360
diff --git a/tests/userprog/no-vm/Rubric b/tests/userprog/no-vm/Rubric
new file mode 100644
index 0000000..c3816c6
--- /dev/null
+++ b/tests/userprog/no-vm/Rubric
@@ -0,0 +1,3 @@
+Functionality of features that VM might break:
+
+1       multi-oom
diff --git a/tests/userprog/no-vm/multi-oom.c b/tests/userprog/no-vm/multi-oom.c
new file mode 100644
index 0000000..6a4472d
--- /dev/null
+++ b/tests/userprog/no-vm/multi-oom.c
@@ -0,0 +1,179 @@
+/* Recursively executes itself until the child fails to execute.
+   We expect that at least 30 copies can run.
+
+   We count how many children your kernel was able to execute
+   before it fails to start a new process.  We require that,
+   if a process doesn't actually get to start, exec() must
+   return -1, not a valid PID.
+
+   We repeat this process 10 times, checking that your kernel
+   allows for the same level of depth every time.
+
+   In addition, some processes will spawn children that terminate
+   abnormally after allocating some resources.
+
+   Written by Godmar Back <godmar@gmail.com>
+ */
+
+#include <debug.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <syscall.h>
+#include <random.h>
+#include "tests/lib.h"
+
+static const int EXPECTED_DEPTH_TO_PASS = 30;
+static const int EXPECTED_REPETITIONS = 10;
+
+const char *test_name = "multi-oom";
+
+enum child_termination_mode { RECURSE, CRASH };
+
+/* Spawn a recursive copy of ourselves, passing along instructions
+   for the child. */
+static pid_t
+spawn_child (int c, enum child_termination_mode mode)
+{
+  char child_cmd[128];
+  snprintf (child_cmd, sizeof child_cmd,
+            "%s %d %s", test_name, c, mode == CRASH ? "-k" : "");
+  return exec (child_cmd);
+}
+
+/* Open a number of files (and fail to close them).
+   The kernel must free any kernel resources associated
+   with these file descriptors. */
+static void
+consume_some_resources (void)
+{
+  int fd, fdmax = 126;
+
+  /* Open as many files as we can, up to fdmax.
+     Depending on how file descriptors are allocated inside
+     the kernel, open() may fail if the kernel is low on memory.
+     A low-memory condition in open() should not lead to the
+     termination of the process.  */
+  for (fd = 0; fd < fdmax; fd++)
+    if (open (test_name) == -1)
+      break;
+}
+
+/* Consume some resources, then terminate this process
+   in some abnormal way.  */
+static int NO_INLINE
+consume_some_resources_and_die (int seed)
+{
+  consume_some_resources ();
+  random_init (seed);
+  int *PHYS_BASE = (int *)0xC0000000;
+
+  switch (random_ulong () % 5)
+    {
+      case 0:
+        *(int *) NULL = 42;
+
+      case 1:
+        return *(int *) NULL;
+
+      case 2:
+        return *PHYS_BASE;
+
+      case 3:
+        *PHYS_BASE = 42;
+
+      case 4:
+        open ((char *)PHYS_BASE);
+        exit (-1);
+
+      default:
+        NOT_REACHED ();
+    }
+  return 0;
+}
+
+/* The first copy is invoked without command line arguments.
+   Subsequent copies are invoked with a parameter 'depth'
+   that describes how many parent processes preceded them.
+   Each process spawns one or multiple recursive copies of
+   itself, passing 'depth+1' as depth.
+
+   Some children are started with the '-k' flag, which will
+   result in abnormal termination.
+ */
+int
+main (int argc, char *argv[])
+{
+  int n;
+
+  n = argc > 1 ? atoi (argv[1]) : 0;
+  bool is_at_root = (n == 0);
+  if (is_at_root)
+    msg ("begin");
+
+  /* If -k is passed, crash this process. */
+  if (argc > 2 && !strcmp(argv[2], "-k"))
+    {
+      consume_some_resources_and_die (n);
+      NOT_REACHED ();
+    }
+
+  int howmany = is_at_root ? EXPECTED_REPETITIONS : 1;
+  int i, expected_depth = -1;
+
+  for (i = 0; i < howmany; i++)
+    {
+      pid_t child_pid;
+
+      /* Spawn a child that will be abnormally terminated.
+         To speed the test up, do this only for processes
+         spawned at a certain depth. */
+      if (n > EXPECTED_DEPTH_TO_PASS/2)
+        {
+          child_pid = spawn_child (n + 1, CRASH);
+          if (child_pid != -1)
+            {
+              if (wait (child_pid) != -1)
+                fail ("crashed child should return -1.");
+            }
+          /* If spawning this child failed, so should
+             the next spawn_child below. */
+        }
+
+      /* Now spawn the child that will recurse. */
+      child_pid = spawn_child (n + 1, RECURSE);
+
+      /* If maximum depth is reached, return result. */
+      if (child_pid == -1)
+        return n;
+
+      /* Else wait for child to report how deeply it was able to recurse. */
+      int reached_depth = wait (child_pid);
+      if (reached_depth == -1)
+        fail ("wait returned -1.");
+
+      /* Record the depth reached during the first run; on subsequent
+         runs, fail if those runs do not match the depth achieved on the
+         first run. */
+      if (i == 0)
+        expected_depth = reached_depth;
+      else if (expected_depth != reached_depth)
+        fail ("after run %d/%d, expected depth %d, actual depth %d.",
+              i, howmany, expected_depth, reached_depth);
+      ASSERT (expected_depth == reached_depth);
+    }
+
+  consume_some_resources ();
+
+  if (n == 0)
+    {
+      if (expected_depth < EXPECTED_DEPTH_TO_PASS)
+        fail ("should have forked at least %d times.", EXPECTED_DEPTH_TO_PASS);
+      msg ("success. program forked %d times.", howmany);
+      msg ("end");
+    }
+
+  return expected_depth;
+}
+// vim: sw=2
diff --git a/tests/userprog/no-vm/multi-oom.ck b/tests/userprog/no-vm/multi-oom.ck
new file mode 100644
index 0000000..59a0bcd
--- /dev/null
+++ b/tests/userprog/no-vm/multi-oom.ck
@@ -0,0 +1,10 @@
+# -*- perl -*-
+use strict;
+use warnings;
+use tests::tests;
+check_expected (IGNORE_USER_FAULTS => 1, IGNORE_EXIT_CODES => 1, [<<'EOF']);
+(multi-oom) begin
+(multi-oom) success. program forked 10 times.
+(multi-oom) end
+EOF
+pass;