tools: if the execdir is the builddir, add it to the path

When running libinput tools from the builddir, look up the subtools in the
builddir as well. Otherwise, add the install prefix to the list of lookup
locations.

This ensures that a) we're running builddir stuff against builddir stuff, but
also b) that we're not running builddir stuff against installed stuff because
that may give us false positives.

The test was squashed in from a separate patch and was
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

meson.build

@@ -31,6 +31,7 @@ add_project_arguments(cppflags, language : 'cpp')
 
 config_h = configuration_data()
 config_h.set('_GNU_SOURCE', '1')
+config_h.set_quoted('MESON_BUILD_ROOT', meson.build_root())
 
 prefix = '''#define _GNU_SOURCE 1
 #include <assert.h>
@@ -688,6 +689,23 @@ executable('ptraccel-debug',
 	   install : false
 	   )
 
+# the libinput tools check whether we execute from the builddir, this is
+# the test to verify that lookup. We test twice, once as normal test
+# run from the builddir, once after copying to /tmp
+test_builddir_lookup = executable('test-builddir-lookup',
+				  'tools/test-builddir-lookup.c',
+				  dependencies : [ dep_tools_shared],
+				  include_directories : [includes_src, includes_include],
+				  install : false)
+test('tools-builddir-lookup',
+     test_builddir_lookup,
+     args : ['--builddir-is-set'])
+test('tools-builddir-lookup-installed',
+     find_program('tools/helper-copy-and-exec-from-tmp.sh'),
+     args : [test_builddir_lookup.full_path(), '--builddir-is-null'],
+     env : ['LD_LIBRARY_PATH=@0@'.format(meson.build_root())],
+     workdir : '/tmp')
+
 ############ tests ############
 
 test_symbols_leak = find_program('test/symbols-leak-test.in')

tools/helper-copy-and-exec-from-tmp.sh

@@ -0,0 +1,18 @@
+#!/bin/bash -x
+#
+# Usage: helper-copy-and-exec-from-tmp.sh /path/to/binary [args]
+#
+# Copies the given binary into a unique file in /tmp and executes it with
+# [args]. Exits with the same return code as the binary did.
+
+executable="$1"
+shift
+
+target_name=$(mktemp)
+cp "$executable" "$target_name"
+chmod +x "$target_name"
+
+"$target_name" "$@"
+rc=$?
+rm "$target_name"
+exit $rc

tools/shared.c

@@ -467,18 +467,51 @@ out:
 	return is_touchpad;
 }
 
+/* Try to read the directory we're executing from and if it matches the
+ * builddir, return it as path. Otherwise, return NULL.
+ */
+char *
+tools_execdir_is_builddir(void)
+{
+	char execdir[PATH_MAX] = {0};
+	char *pathsep;
+	ssize_t sz;
+
+	sz = readlink("/proc/self/exe", execdir, sizeof(execdir) - 1);
+	if (sz <= 0 || sz == sizeof(execdir) - 1)
+		return NULL;
+
+	/* readlink doesn't terminate the string and readlink says
+	   anything past sz is undefined */
+	execdir[sz + 1] = '\0';
+
+	pathsep = strrchr(execdir, '/');
+	if (!pathsep)
+		return NULL;
+
+	*pathsep = '\0';
+	if (!streq(execdir, MESON_BUILD_ROOT))
+		return NULL;
+
+	return safe_strdup(execdir);
+}
+
 static inline void
 setup_path(void)
 {
 	const char *path = getenv("PATH");
 	char new_path[PATH_MAX];
+	char *builddir;
+
+	builddir = tools_execdir_is_builddir();
 
 	snprintf(new_path,
 		 sizeof(new_path),
 		 "%s:%s",
-		 LIBINPUT_TOOL_PATH,
+		 builddir ? builddir : LIBINPUT_TOOL_PATH,
 		 path ? path : "");
 	setenv("PATH", new_path, 1);
+	free(builddir);
 }
 
 int

tools/shared.h

@@ -119,4 +119,7 @@ tools_list_device_quirks(struct quirks_context *ctx,
 			 void (*callback)(void *userdata, const char *str),
 			 void *userdata);
 
+char *
+tools_execdir_is_builddir(void);
+
 #endif

tools/test-builddir-lookup.c

@@ -0,0 +1,47 @@
+/*
+ * Copyright © 2018 Red Hat, Inc.
+ *
+ * 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 "config.h"
+#include "libinput-util.h"
+#include "shared.h"
+
+int main(int argc, char **argv) {
+	char *builddir;
+	char *mode;
+
+	assert(argc == 2);
+	mode = argv[1];
+
+	builddir = tools_execdir_is_builddir();
+	if (streq(mode, "--builddir-is-null")) {
+		assert(builddir == NULL);
+	} else if (streq(mode, "--builddir-is-set")) {
+		assert(builddir != NULL);
+		assert(streq(MESON_BUILD_ROOT, builddir));
+		free(builddir);
+	} else {
+		abort();
+	}
+
+	return 0;
+}