[PATCH xserver] test: Add a test for the overflow bug in bigreqs.

[Eric Anholt]

The failing struct comes from the python test written by Michal Srb
<msrb at suse.com>.

v2: Use a drawable (root window) and gc, so that PolyLines hopefully
    actually tries processing things.  However, the request seems to
    process successfully so the poll() just stalls out.  However, this
    does let us distinguish between detecting the bigrequests error
    and not, at least.
v3: Clean up the description of what we expect the poll() call to do.

Signed-off-by: Eric Anholt <eric at anholt.net>
---
 test/bigreq/meson.build      |  8 +++++
 test/bigreq/request-length.c | 71 ++++++++++++++++++++++++++++++++++++++++++++
 test/meson.build             |  1 +
 3 files changed, 80 insertions(+)
 create mode 100644 test/bigreq/meson.build
 create mode 100644 test/bigreq/request-length.c

diff --git a/test/bigreq/meson.build b/test/bigreq/meson.build
new file mode 100644
index 000000000000..9462ede31dca
--- /dev/null
+++ b/test/bigreq/meson.build
@@ -0,0 +1,8 @@
+xcb_dep = dependency('xcb', required: false)
+
+if get_option('xvfb')
+    if xcb_dep.found()
+        requestlength = executable('request-length', 'request-length.c', dependencies: xcb_dep)
+        test('request-length', simple_xinit, args: [requestlength, '--', xvfb_server])
+    endif
+endif
diff --git a/test/bigreq/request-length.c b/test/bigreq/request-length.c
new file mode 100644
index 000000000000..82d712e0624d
--- /dev/null
+++ b/test/bigreq/request-length.c
@@ -0,0 +1,71 @@
+/*
+ * Copyright © 2017 Broadcom
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <poll.h>
+#include <xcb/xcb.h>
+#include <xcb/bigreq.h>
+
+int main(int argc, char **argv)
+{
+    xcb_connection_t *c = xcb_connect(NULL, NULL);
+    xcb_screen_t *screen = xcb_setup_roots_iterator(xcb_get_setup(c)).data;
+    xcb_gcontext_t gc = xcb_generate_id(c);
+    int fd = xcb_get_file_descriptor(c);
+    struct {
+        uint8_t reqtype;
+        uint8_t coordmode;
+        uint16_t length;
+        uint32_t length_bigreq;
+        uint32_t drawable;
+        uint32_t gc;
+    } polyline_req = {
+        .reqtype = XCB_POLY_LINE,
+        .drawable = screen->root,
+        .gc = gc,
+
+        /* This is the value that triggers the bug. */
+        .length_bigreq = 0,
+    };
+
+    xcb_create_gc(c, gc, screen->root, 0, NULL);
+
+    free(xcb_big_requests_enable_reply(c, xcb_big_requests_enable(c), NULL));
+
+    /* Manually write out the bad request.  XCB can't help us here.*/
+    write(fd, &polyline_req, sizeof(polyline_req));
+
+    /* Block until the server has processed our mess and throws an
+     * error.  If it never throws an error, then it probably did
+     * things wrong (either a crash, or "successfully" processing our
+     * broken request).
+     */
+    struct pollfd pfd = {
+        .fd = fd,
+        .events = POLLIN,
+    };
+    poll(&pfd, 1, -1);
+
+    return 0;
+}
diff --git a/test/meson.build b/test/meson.build
index 3e482d6f19cd..d413e9da5323 100644
--- a/test/meson.build
+++ b/test/meson.build
@@ -23,4 +23,5 @@ if get_option('xvfb')
     endif
 endif
 
+subdir('bigreq')
 subdir('sync')
-- 
2.14.2