Add client which uses up finite compositor resources

This makes it possible to check how compositors behave when resource
limits are reached. The three initial modes check what happens when
file descriptors, memory map areas, and allocated memory are exhausted.

Memory map exhaustion is implemented by making and retaining many
wl_shm_pool objects, each of which leads to the compositor making an
mmap call.

Allocated memory exhaustion is implemented by progressively
building up wl_region objects; the client only sends random and
disjoint wl_region.add messages, but the compositor must remember
them all.

File descriptor exhaustion is achieved by creating many buffers
based on the same dmabuf. Compositors do not deduplicate the file
descriptors sent to create the buffers.

In all cases, the resource thief client pays much less than the
compositor, because it reuses an object that the compositor
has no reason to deduplicate, or creates a complicated remote
object without storing a local copy.

Author: mstoeckl

README.md

@@ -15,6 +15,7 @@ ninja -C build
 * `frame-callback`: requests frame callbacks indefinitely
 * `resize-loop`: resizes itself indefinitely
 * `resizor`: uses buffer position to initiate a client-side resize
+* `resource-thief`: makes the compositor run out of (fd or memory) resources
 * `sigbus`: trigger SIGBUS in the compositor by shrinking a shm file
 * `slow-ack-configure`: responds to configure events very slowly
 * `subsurfaces`: displays a bunch of subsurfaces and lets you reorder them

meson.build

@@ -3,7 +3,7 @@ project(
 	'c',
 	version: '0.0.0',
 	license: 'MIT',
-	meson_version: '>=0.47.0',
+	meson_version: '>=0.49.0',
 	default_options: [
 		'c_std=c11',
 		'warning_level=2',
@@ -23,6 +23,7 @@ wayland_client = dependency('wayland-client')
 wayland_server = dependency('wayland-server')
 wayland_protos = dependency('wayland-protocols', version: '>=1.14')
 math = cc.find_library('m', required: false)
+gbm = dependency('gbm', disabler: true)
 
 subdir('protocol')
 
@@ -67,6 +68,10 @@ clients = {
 	'resizor': {
 		'src': 'resizor.c',
 	},
+	'resource-thief': {
+		'src': 'resource-thief.c',
+		'deps': [gbm],
+	},
 	'sigbus': {
 		'src': 'sigbus.c',
 	},

protocol/meson.build

@@ -12,6 +12,7 @@ endif
 client_protocols = [
 	[wl_protocol_dir, 'stable/xdg-shell/xdg-shell.xml'],
 	[wl_protocol_dir, 'unstable/xdg-decoration/xdg-decoration-unstable-v1.xml'],
+	[wl_protocol_dir, 'unstable/linux-dmabuf/linux-dmabuf-unstable-v1.xml'],
 ]
 
 client_protos_src = []