testsuite: Check the list of loaded modules after a test

Add a ->modules_loaded member to struct test, which is a comma-separated
list of modules that should be present after the test finishes. Both
missing and excess modules cause an error.

testsuite/test-init.c

@@ -74,6 +74,7 @@ static DEFINE_TEST(test_insert,
 		[TC_ROOTFS] = TESTSUITE_ROOTFS "test-init/",
 		[TC_INIT_MODULE_RETCODES] = "bla:1:20",
 	},
+	.modules_loaded = "ext4",
 	.need_spawn = true);
 
 static noreturn int test_remove(const struct test *t)

testsuite/test-modprobe.c

@@ -91,7 +91,9 @@ static DEFINE_TEST(modprobe_show_alias_to_none,
 	},
 	.output = {
 		.out = TESTSUITE_ROOTFS "test-modprobe/show-depends/correct-psmouse.txt",
-	});
+	},
+	.modules_loaded = "",
+	);
 
 
 static noreturn int modprobe_builtin(const struct test *t)
@@ -131,7 +133,9 @@ static DEFINE_TEST(modprobe_softdep_loop,
 		[TC_UNAME_R] = "4.4.4",
 		[TC_ROOTFS] = TESTSUITE_ROOTFS "test-modprobe/softdep-loop",
 		[TC_INIT_MODULE_RETCODES] = "",
-	});
+	},
+	.modules_loaded = "btusb,bluetooth",
+	);
 
 static noreturn int modprobe_install_cmd_loop(const struct test *t)
 {
@@ -156,6 +160,7 @@ static DEFINE_TEST(modprobe_install_cmd_loop,
 		{ "MODPROBE", ABS_TOP_BUILDDIR "/tools/modprobe" },
 		{ }
 		},
+	.modules_loaded = "snd,snd-pcm",
 	);
 
 static noreturn int modprobe_param_kcmdline(const struct test *t)
@@ -178,7 +183,9 @@ static DEFINE_TEST(modprobe_param_kcmdline,
 	},
 	.output = {
 		.out = TESTSUITE_ROOTFS "test-modprobe/module-param-kcmdline/correct.txt",
-	});
+	},
+	.modules_loaded = "",
+	);
 
 
 static const struct test *tests[] = {

testsuite/testsuite.c

@@ -20,6 +20,7 @@
 #include <fcntl.h>
 #include <getopt.h>
 #include <limits.h>
+#include <dirent.h>
 #include <stdio.h>
 #include <stdarg.h>
 #include <stdlib.h>
@@ -528,12 +529,189 @@ fail:
 	return true;
 }
 
+static int cmp_modnames(const void *m1, const void *m2)
+{
+	const char *s1 = *(char *const *)m1;
+	const char *s2 = *(char *const *)m2;
+	int i;
+
+	for (i = 0; s1[i] || s2[i]; i++) {
+		char c1 = s1[i], c2 = s2[i];
+		if (c1 == '-')
+			c1 = '_';
+		if (c2 == '-')
+			c2 = '_';
+		if (c1 != c2)
+			return c1 - c2;
+	}
+	return 0;
+}
+
+/*
+ * Store the expected module names in buf and return a list of pointers to
+ * them.
+ */
+static const char **read_expected_modules(const struct test *t,
+		char **buf, int *count)
+{
+	const char **res;
+	int len;
+	int i;
+	char *p;
+
+	if (t->modules_loaded[0] == '\0') {
+		*count = 0;
+		*buf = NULL;
+		return NULL;
+	}
+	*buf = strdup(t->modules_loaded);
+	if (!*buf) {
+		*count = -1;
+		return NULL;
+	}
+	len = 1;
+	for (p = *buf; *p; p++)
+		if (*p == ',')
+			len++;
+	res = malloc(sizeof(char *) * len);
+	if (!res) {
+		perror("malloc");
+		*count = -1;
+		free(*buf);
+		*buf = NULL;
+		return NULL;
+	}
+	i = 0;
+	res[i++] = *buf;
+	for (p = *buf; i < len; p++)
+		if (*p == ',') {
+			*p = '\0';
+			res[i++] = p + 1;
+		}
+	*count = len;
+	return res;
+}
+
+static char **read_loaded_modules(const struct test *t, char **buf, int *count)
+{
+	char dirname[PATH_MAX];
+	DIR *dir;
+	struct dirent *dirent;
+	int i;
+	int len = 0, bufsz;
+	char **res = NULL;
+	char *p;
+	const char *rootfs = t->config[TC_ROOTFS] ? t->config[TC_ROOTFS] : "";
+
+	/* Store the entries in /sys/module to res */
+	if (snprintf(dirname, sizeof(dirname), "%s/sys/module", rootfs)
+			>= (int)sizeof(dirname)) {
+		ERR("rootfs path too long: %s\n", rootfs);
+		*buf = NULL;
+		len = -1;
+		goto out;
+	}
+	dir = opendir(dirname);
+	/* not an error, simply return empty list */
+	if (!dir) {
+		*buf = NULL;
+		goto out;
+	}
+	bufsz = 0;
+	while ((dirent = readdir(dir))) {
+		if (dirent->d_name[0] == '.')
+			continue;
+		len++;
+		bufsz += strlen(dirent->d_name) + 1;
+	}
+	res = malloc(sizeof(char *) * len);
+	if (!res) {
+		perror("malloc");
+		len = -1;
+		goto out_dir;
+	}
+	*buf = malloc(bufsz);
+	if (!*buf) {
+		perror("malloc");
+		free(res);
+		res = NULL;
+		len = -1;
+		goto out_dir;
+	}
+	rewinddir(dir);
+	i = 0;
+	p = *buf;
+	while ((dirent = readdir(dir))) {
+		int size;
+
+		if (dirent->d_name[0] == '.')
+			continue;
+		size = strlen(dirent->d_name) + 1;
+		memcpy(p, dirent->d_name, size);
+		res[i++] = p;
+		p += size;
+	}
+out_dir:
+	closedir(dir);
+out:
+	*count = len;
+	return res;
+}
+
+static int check_loaded_modules(const struct test *t)
+{
+	int l1, l2, i1, i2;
+	const char **a1;
+	char **a2;
+	char *buf1, *buf2;
+	int err = false;
+
+	a1 = read_expected_modules(t, &buf1, &l1);
+	if (l1 < 0)
+		return err;
+	a2 = read_loaded_modules(t, &buf2, &l2);
+	if (l2 < 0)
+		goto out_a1;
+	qsort(a1, l1, sizeof(char *), cmp_modnames);
+	qsort(a2, l2, sizeof(char *), cmp_modnames);
+	i1 = i2 = 0;
+	err = true;
+	while (i1 < l1 || i2 < l2) {
+		int cmp;
+
+		if (i1 >= l1)
+			cmp = 1;
+		else if (i2 >= l2)
+			cmp = -1;
+		else
+			cmp = cmp_modnames(&a1[i1], &a2[i2]);
+		if (cmp == 0) {
+			i1++;
+			i2++;
+		} else if (cmp < 0) {
+			err = false;
+			ERR("module %s not loaded\n", a1[i1]);
+			i1++;
+		} else  {
+			err = false;
+			ERR("module %s is loaded but should not be \n", a2[i2]);
+			i2++;
+		}
+	}
+	free(a2);
+	free(buf2);
+out_a1:
+	free(a1);
+	free(buf1);
+	return err;
+}
+
 static inline int test_run_parent(const struct test *t, int fdout[2],
 				int fderr[2], int fdmonitor[2], pid_t child)
 {
 	pid_t pid;
 	int err;
-	bool matchout;
+	bool matchout, match_modules;
 
 	/* Close write-fds */
 	if (t->output.out != NULL)
@@ -578,16 +756,21 @@ static inline int test_run_parent(const struct test *t, int fdout[2],
 
 	if (matchout)
 		matchout = check_generated_files(t);
+	if (t->modules_loaded)
+		match_modules = check_loaded_modules(t);
+	else
+		match_modules = true;
 
 	if (t->expected_fail == false) {
 		if (err == 0) {
-			if (matchout)
+			if (matchout && match_modules)
 				LOG("%sPASSED%s: %s\n",
 					ANSI_HIGHLIGHT_GREEN_ON, ANSI_HIGHLIGHT_OFF,
 					t->name);
 			else {
-				ERR("%sFAILED%s: exit ok but outputs do not match: %s\n",
+				ERR("%sFAILED%s: exit ok but %s do not match: %s\n",
 					ANSI_HIGHLIGHT_RED_ON, ANSI_HIGHLIGHT_OFF,
+					matchout ? "loaded modules" : "outputs",
 					t->name);
 				err = EXIT_FAILURE;
 			}

testsuite/testsuite.h

@@ -95,6 +95,8 @@ struct test {
 		 */
 		const struct keyval *files;
 	} output;
+	/* comma-separated list of loaded modules at the end of the test */
+	const char *modules_loaded;
 	testfunc func;
 	const char *config[_TC_LAST];
 	const char *path;