util: add support for generating UUIDs

Co-authored-by: Jason Francis <cycl0ps@tuta.io>

.builds/alpine.yml

@@ -7,6 +7,7 @@ packages:
   - mesa-dev
   - meson
   - pixman-dev
+  - util-linux-dev
   - wayland-dev
   - wayland-protocols
   - xcb-util-image-dev

.builds/freebsd.yml

@@ -10,6 +10,7 @@ packages:
 - graphics/png
 - graphics/wayland
 - graphics/wayland-protocols
+- misc/e2fsprogs-libuuid
 - multimedia/ffmpeg
 - x11/libX11
 - x11/libinput

README.md

@@ -55,6 +55,7 @@ Install dependencies:
 * pixman
 * systemd (optional, for logind support)
 * elogind (optional, for logind support on systems without systemd)
+* libuuid (optional, for xdg-foreign support)
 
 If you choose to enable X11 support:
 

include/util/uuid.h

@@ -0,0 +1,8 @@
+#ifndef UTIL_UUID_H
+#define UTIL_UUID_H
+
+#include <stdbool.h>
+
+bool generate_uuid(char out[static 37]);
+
+#endif

meson.build

@@ -109,6 +109,9 @@ pixman = dependency('pixman-1')
 math = cc.find_library('m')
 rt = cc.find_library('rt')
 
+uuid = dependency('uuid', required: false)
+uuid_create = cc.has_function('uuid_create')
+
 wlr_files = []
 wlr_deps = [
 	wayland_server,

util/meson.build

@@ -7,3 +7,11 @@ wlr_files += files(
 	'signal.c',
 	'time.c',
 )
+
+if uuid.found()
+	wlr_deps += uuid
+	add_project_arguments('-DHAS_LIBUUID=1', language: 'c')
+else
+	add_project_arguments('-DHAS_LIBUUID=0', language: 'c')
+endif
+wlr_files += files('uuid.c')

util/uuid.c

@@ -0,0 +1,33 @@
+#include <uuid.h>
+#include "util/uuid.h"
+
+#if HAS_LIBUUID
+bool generate_uuid(char out[static 37]) {
+	uuid_t uuid;
+	uuid_generate_random(uuid);
+	uuid_unparse(uuid, out);
+	return true;
+}
+#else
+#include <string.h>
+#include <stdlib.h>
+
+bool generate_uuid(char out[static 37]) {
+	uuid_t uuid;
+	uint32_t status;
+	uuid_create(&uuid, &status);
+	if (status != uuid_s_ok) {
+		return false;
+	}
+	char *str;
+	uuid_to_string(&uuid, &str, &status);
+	if (status != uuid_s_ok) {
+		return false;
+	}
+
+	assert(strlen(str) + 1 == 37);
+	memcpy(out, str, sizeof(out));
+	free(str);
+	return true;
+}
+#endif