1 files changed, 190 insertions, 0 deletions
diff --git a/user/usr/bin/tests/eatmem.c b/user/usr/bin/tests/eatmem.c
new file mode 100644
index 0000000..f4735aa
--- /dev/null
+++ b/user/usr/bin/tests/eatmem.c
@@ -0,0 +1,190 @@
+/*
+ * Eats kernel memory. Lots of it.
+ */
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <stdio.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+#include <test/test.h>
+
+#define PAGE_SIZE 4096
+
+static void eat(void *addr, int *count, int *num)
+{
+    int status;
+    test_fork_begin()
+    {
+        if (*num <= 0)
+        {
+            /* Eat the memory until we die */
+            while (1)
+            {
+                char foo = *((char *)addr + ((*count)++ * PAGE_SIZE));
+                if ((*count & 0x7f) == 0)
+                {
+                    printf("Ate %d pages\n", *count);
+                }
+            }
+        }
+        else
+        {
+            /* Eat until we have the necessary number of pages */
+            while (*count < *num)
+            {
+                char foo = *((char *)addr + ((*count)++ * PAGE_SIZE));
+                if ((*count & 0x7f) == 0)
+                {
+                    printf("Ate %d pages\n", *count);
+                }
+            }
+        }
+    }
+    test_fork_end(&status);
+    if (*num <= 0 && EFAULT != status)
+    {
+        fprintf(stderr, "Child process didn't segfault!\n");
+        exit(1);
+    }
+    if (*num < 0)
+    {
+        /* Free the required number of pages */
+        munmap(addr, PAGE_SIZE * (-*num));
+        printf("Gave back %d pages\n", -*num);
+        *count += *num;
+    }
+}
+
+#define FLAG_DAEMON "-d"
+#define FLAG_INFINITE "-i"
+#define FLAG_ITER "-y"
+#define FLAG_NUM "-#"
+
+#define OPT_DAEMON 1
+#define OPT_INFINITE 2
+#define OPT_ITER 4
+#define OPT_NUM 8
+
+int parse_args(int argc, char **argv, int *opts, int *iter, int *num)
+{
+    int i;
+    *opts = *iter = *num = 0;
+    for (i = 1; i < argc; i++)
+    {
+        if (!strcmp(FLAG_DAEMON, argv[i]))
+        {
+            *opts |= OPT_DAEMON;
+        }
+        else if (!strcmp(FLAG_INFINITE, argv[i]))
+        {
+            *opts |= OPT_INFINITE;
+        }
+        else if (!strcmp(FLAG_ITER, argv[i]))
+        {
+            *opts |= OPT_ITER;
+            if (++i >= argc ||
+                (errno = 0, *iter = strtol(argv[i], NULL, 0), 0 != errno))
+            {
+                return -1;
+            }
+        }
+        else if (!strcmp(FLAG_NUM, argv[i]))
+        {
+            *opts |= OPT_NUM;
+            if (++i >= argc ||
+                (errno = 0, *num = strtol(argv[i], NULL, 0), 0 != errno))
+            {
+                return -1;
+            }
+        }
+        else
+        {
+            return -1;
+        }
+    }
+    return 0;
+}
+
+int main(int argc, char **argv)
+{
+    int status;
+    void *addr;
+    int *count;
+    int *opts, *iter, *num;
+
+    /* Get our huge mess of space. We map this as a bunch of regions at the
+     * beginning so that unmapping (above) actually does something. */
+    if (MAP_FAILED ==
+        (addr = mmap(NULL, PAGE_SIZE * 10000, PROT_READ | PROT_WRITE,
+                     MAP_SHARED | MAP_ANON, -1, 0)))
+    {
+        return 1;
+    }
+
+    int i;
+    for (i = 0; i < 40; i++)
+    {
+        if (MAP_FAILED == mmap((char *)addr + PAGE_SIZE * 25 * i,
+                               PAGE_SIZE * 25, PROT_READ | PROT_WRITE,
+                               MAP_FIXED | MAP_SHARED | MAP_ANON, -1, 0))
+        {
+            return 1;
+        }
+    }
+
+    /* Set the initial count */
+    count = addr;
+    *count = 0;
+    opts = count + 1;
+    iter = count + 2;
+    num = count + 3;
+
+    if (0 > parse_args(argc, argv, opts, iter, num))
+    {
+        fprintf(
+            stderr,
+            "USAGE: eatmem [options]\n" FLAG_DAEMON
+            "          run as daemon\n" FLAG_INFINITE
+            "          run forever\n" FLAG_ITER
+            " [num]    number of iterations to yield\n" FLAG_NUM
+            " [num]    number of pages to eat (if negative, to relinquish)\n");
+        return 1;
+    }
+
+    addr = (char *)addr + PAGE_SIZE;
+
+    printf("OM NOM NOM NOM\n");
+
+    if (*opts & OPT_DAEMON)
+    {
+        if (fork())
+        {
+            exit(0);
+        }
+    }
+
+    eat(addr, count, num);
+
+    printf("Ate %d pages in total\n", *count);
+
+    if (*opts & OPT_INFINITE)
+    {
+        while (1)
+        {
+            sched_yield();
+        }
+    }
+    else if (*opts & OPT_ITER)
+    {
+        while (--iter)
+        {
+            sched_yield();
+        }
+    }
+    printf("Giving memory back now\n");
+    return 0;
+}