Add failed fmap test

tests/Makefile

@@ -11,7 +11,7 @@ FAILING_TESTS=tls \
 	mkfifo \
 	sigchld \
 	stdlib/ptsname \
-	sys_mman \
+	sys_mman/fmap \
 	signals/pthread_kill-child \
 	unistd/isatty \
 	unistd/link \
@@ -276,6 +276,7 @@ VARIED_NAMES=\
 	stdlib/mktemp \
 	stdlib/realpath \
 	sys_epoll/epoll \
+	sys_mman/mmap \
 	sys_resource/constants \
 	sys_socket/getpeername \
 	sys_stat/stat \

tests/sys_mman/fmap.c

@@ -0,0 +1,103 @@
+// copied from autoconf mmap test, currently panicking kernel
+
+/* Thanks to Mike Haertel and Jim Avera for this test.
+   Here is a matrix of mmap possibilities:
+	mmap private not fixed
+	mmap private fixed at somewhere currently unmapped
+	mmap private fixed at somewhere already mapped
+	mmap shared not fixed
+	mmap shared fixed at somewhere currently unmapped
+	mmap shared fixed at somewhere already mapped
+   For private mappings, we should verify that changes cannot be read()
+   back from the file, nor mmap's back from the file at a different
+   address.  (There have been systems where private was not correctly
+   implemented like the infamous i386 svr4.0, and systems where the
+   VM page cache was not coherent with the file system buffer cache
+   like early versions of FreeBSD and possibly contemporary NetBSD.)
+   For shared mappings, we should conversely verify that changes get
+   propagated back to all the places they're supposed to be.
+
+   Grep wants private fixed already mapped.
+   The main things grep needs to know about mmap are:
+   * does it exist and is it safe to write into the mmap'd area
+   * how to use it (BSD variants)  */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+
+int
+main (void)
+{
+  char *data, *data2, *data3;
+  const char *cdata2;
+  int i, pagesize;
+  int fd, fd2;
+
+  pagesize = sysconf(_SC_PAGESIZE);
+
+  /* First, make a file with some known garbage in it. */
+  data = (char *) malloc (pagesize);
+  if (!data)
+    return 1;
+  for (i = 0; i < pagesize; ++i)
+    *(data + i) = rand ();
+  umask (0);
+  fd = creat ("conftest.mmap", 0600);
+  if (fd < 0)
+    return 2;
+  if (write (fd, data, pagesize) != pagesize)
+    return 3;
+  close (fd);
+
+  /* Next, check that the tail of a page is zero-filled.  File must have
+     non-zero length, otherwise we risk SIGBUS for entire page.  */
+  fd2 = open ("conftest.txt", O_RDWR | O_CREAT | O_TRUNC, 0600);
+  if (fd2 < 0)
+    return 4;
+  cdata2 = "";
+  if (write (fd2, cdata2, 1) != 1)
+    return 5;
+  data2 = (char *) mmap (0, pagesize, PROT_READ | PROT_WRITE, MAP_SHARED, fd2, 0L);
+  if (data2 == MAP_FAILED)
+    return 6;
+  for (i = 0; i < pagesize; ++i)
+    if (*(data2 + i))
+      return 7;
+  close (fd2);
+  if (munmap (data2, pagesize))
+    return 8;
+
+  /* Next, try to mmap the file at a fixed address which already has
+     something else allocated at it.  If we can, also make sure that
+     we see the same garbage.  */
+  fd = open ("conftest.mmap", O_RDWR);
+  if (fd < 0)
+    return 9;
+  if (data2 != mmap (data2, pagesize, PROT_READ | PROT_WRITE,
+		     MAP_PRIVATE | MAP_FIXED, fd, 0L))
+    return 10;
+  for (i = 0; i < pagesize; ++i)
+    if (*(data + i) != *(data2 + i))
+      return 11;
+
+  /* Finally, make sure that changes to the mapped area do not
+     percolate back to the file as seen by read().  (This is a bug on
+     some variants of i386 svr4.0.)  */
+  for (i = 0; i < pagesize; ++i)
+    *(data2 + i) = *(data2 + i) + 1;
+  data3 = (char *) malloc (pagesize);
+  if (!data3)
+    return 12;
+  if (read (fd, data3, pagesize) != pagesize)
+    return 13;
+  for (i = 0; i < pagesize; ++i)
+    if (*(data + i) != *(data3 + i))
+      return 14;
+  close (fd);
+  free (data);
+  free (data3);
+  return 0;
+}