Add regress test for MAP_INHERIT_ZERO.

2 files changed, 135 insertions, 0 deletions

diff --git a/regress/sys/uvm/minherit_zero/Makefile b/regress/sys/uvm/minherit_zero/Makefile
new file mode 100644
index 00000000000..9e054db9f59
--- /dev/null
+++ b/regress/sys/uvm/minherit_zero/Makefile
@@ -0,0 +1,5 @@
+#	$OpenBSD: Makefile,v 1.1 2014/06/13 07:17:54 matthew Exp $
+
+PROG=	minherit_zero
+
+.include <bsd.regress.mk>
diff --git a/regress/sys/uvm/minherit_zero/minherit_zero.c b/regress/sys/uvm/minherit_zero/minherit_zero.c
new file mode 100644
index 00000000000..e7bfa23f7c1
--- /dev/null
+++ b/regress/sys/uvm/minherit_zero/minherit_zero.c
@@ -0,0 +1,130 @@
+/*	$OpenBSD: minherit_zero.c,v 1.1 2014/06/13 07:17:54 matthew Exp $	*/
+/*
+ * Copyright (c) 2014 Google Inc.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/mman.h>
+#include <sys/wait.h>
+#include <assert.h>
+#include <fcntl.h>
+#include <paths.h>
+#include <string.h>
+#include <unistd.h>
+
+#define CHECK(x) assert((x))
+#define CHECK_EQ(a, b) assert((a) == (b))
+#define CHECK_NE(a, b) assert((a) != (b))
+#define CHECK_GE(a, b) assert((a) >= (b))
+
+static int
+ismemset(const void *s, int c, size_t n)
+{
+	const unsigned char *p = s;
+	size_t i;
+
+	for (i = 0; i < n; i++)
+		if (p[i] != c)
+			return (0);
+	return (1);
+}
+
+static void
+wait_for_clean_exit(pid_t pid)
+{
+	int status;
+	CHECK_EQ(pid, waitpid(pid, &status, 0));
+	CHECK(WIFEXITED(status));
+	CHECK_EQ(0, WEXITSTATUS(status));
+}
+
+enum {
+	NPAGES = 4,
+
+	PARENT_BYTE = 42,
+	CHILD_BYTE = 53,
+	GRANDCHILD_BYTE = 65
+};
+
+/*
+ * We map some memory, configure it's inheritance for MAP_INHERIT_ZERO,
+ * then check that when we fork child or grandchild processes, that they
+ * receive new zero'd out memory mappings.  Additionally, we sanity check
+ * that after the child (or grandchild) process exits, that the parent's
+ * memory is still in tact.
+ */
+static void
+dotest(int fd, size_t len, int flags)
+{
+	void *p;
+	pid_t pid;
+
+	p = mmap(NULL, len, PROT_READ|PROT_WRITE, flags, fd, 0);
+	CHECK_NE(MAP_FAILED, p);
+	
+	CHECK_EQ(0, minherit(p, len, MAP_INHERIT_ZERO));
+
+	memset(p, PARENT_BYTE, len);
+
+	pid = fork();
+	CHECK_GE(pid, 0);
+	if (pid == 0) {
+		CHECK(ismemset(p, 0, len));
+		memset(p, CHILD_BYTE, len);
+
+		pid = fork();
+		CHECK_GE(pid, 0);
+		if (pid == 0) {
+			CHECK(ismemset(p, 0, len));
+			memset(p, GRANDCHILD_BYTE, len);
+			_exit(0);
+		}
+
+		wait_for_clean_exit(pid);
+		CHECK(ismemset(p, CHILD_BYTE, len));
+		memset(p, 0, len);
+		_exit(0);
+	}
+
+	wait_for_clean_exit(pid);
+	CHECK(ismemset(p, PARENT_BYTE, len));
+	memset(p, 0, len);
+
+	CHECK_EQ(0, munmap(p, len));
+}
+
+int
+main()
+{
+	long pagesize;
+	size_t len;
+
+	pagesize = sysconf(_SC_PAGESIZE);
+	CHECK_GE(pagesize, 1);
+	len = NPAGES * pagesize;
+
+	/* First run test with private anonymous memory. */
+	dotest(-1, len, MAP_ANON|MAP_PRIVATE);
+
+	/* Test again with shared anonymous memory. */
+	dotest(-1, len, MAP_ANON|MAP_SHARED);
+
+	/* Finally, test with private file mapping. */
+	int fd = open(_PATH_BSHELL, O_RDONLY);
+	CHECK_GE(fd, 0);
+	dotest(fd, len, MAP_FILE|MAP_PRIVATE);
+	CHECK_EQ(0, close(fd));
+
+	return (0);
+}