testsuite: add tests for weak dependencies

The following tests to verify weak dependencies have been implemented:
1) modprobe test to check that related weakdep modules are not loaded
   due to being a weakdep.
2) depmod test to check weakdep output.
3) user test to check that configuration files with weakdep are parsed
   correctly and related weakdep modules can be read correctly from user
   applications.

Signed-off-by: Jose Ignacio Tornos Martinez <jtornosm@redhat.com>
Link: https://lore.kernel.org/r/20240530070836.9438-1-jtornosm@redhat.com
[ Minor whitespace issues and define MODULE_WEAKDEP if it's not defined
  already ]
Signed-off-by: Lucas De Marchi <lucas.de.marchi@gmail.com>

Makefile.am

@@ -262,7 +262,7 @@ TESTSUITE = \
 	testsuite/test-modinfo testsuite/test-util testsuite/test-new-module \
 	testsuite/test-modprobe testsuite/test-blacklist \
 	testsuite/test-dependencies testsuite/test-depmod \
-	testsuite/test-list
+	testsuite/test-list testsuite/test-user
 
 check_PROGRAMS = $(TESTSUITE)
 TESTS = $(TESTSUITE)
@@ -305,6 +305,8 @@ testsuite_test_depmod_LDADD = $(TESTSUITE_LDADD)
 testsuite_test_depmod_CPPFLAGS = $(TESTSUITE_CPPFLAGS)
 testsuite_test_list_LDADD = $(TESTSUITE_LDADD)
 testsuite_test_list_CPPFLAGS = $(TESTSUITE_CPPFLAGS)
+testsuite_test_user_LDADD = $(TESTSUITE_LDADD)
+testsuite_test_user_CPPFLAGS = $(TESTSUITE_CPPFLAGS)
 
 testsuite-distclean:
 	$(RM) -r $(ROOTFS)

testsuite/.gitignore

@@ -18,6 +18,7 @@
 /test-modprobe
 /test-hash
 /test-list
+/test-user
 /rootfs
 /stamp-rootfs
 /test-scratchbuf.log
@@ -52,3 +53,5 @@
 /test-testsuite.trs
 /test-list.log
 /test-list.trs
+/test-user.log
+/test-user.trs

testsuite/module-playground/Makefile

@@ -37,6 +37,8 @@ obj-m += mod-fake-hpsa.o
 obj-m += mod-fake-scsi-mod.o
 obj-m += mod-fake-cciss.o
 
+obj-m += mod-weakdep.o
+
 else
 # only build ARCH-specific module
 ifeq ($(ARCH),)

testsuite/module-playground/mod-weakdep.c

@@ -0,0 +1,19 @@
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/init.h>
+#include <linux/module.h>
+
+#ifndef MODULE_WEAKDEP
+#define MODULE_WEAKDEP(_weakdep) MODULE_INFO(weakdep, _weakdep)
+#endif
+
+static int __init weakdep_init(void)
+{
+	return 0;
+}
+
+module_init(weakdep_init);
+
+MODULE_AUTHOR("Jose Ignacio Tornos Martinez <jtornosm@redhat.com>");
+MODULE_LICENSE("LGPL");
+MODULE_WEAKDEP("mod-simple");

testsuite/rootfs-pristine/test-depmod/check-weakdep/lib/modules/4.4.4/correct-modules.weakdep

@@ -0,0 +1,2 @@
+# Weak dependencies extracted from modules themselves.
+weakdep mod_weakdep mod-simple

testsuite/rootfs-pristine/test-modprobe/weakdep-loop/etc/modprobe.d/dumb-weakdep.conf

@@ -0,0 +1 @@
+weakdep mod-loop-b mod-loop-a mod-simple

testsuite/rootfs-pristine/test-modprobe/weakdep-loop/lib/modules/4.4.4/modules.alias

@@ -0,0 +1 @@
+# Aliases extracted from modules themselves.

testsuite/rootfs-pristine/test-modprobe/weakdep-loop/lib/modules/4.4.4/modules.dep

@@ -0,0 +1,3 @@
+kernel/mod-loop-b.ko:
+kernel/mod-loop-a.ko:
+kernel/mod-simple.ko:

testsuite/rootfs-pristine/test-modprobe/weakdep-loop/lib/modules/4.4.4/modules.devname

@@ -0,0 +1 @@
+# Device nodes to trigger on-demand module loading.

testsuite/rootfs-pristine/test-modprobe/weakdep-loop/lib/modules/4.4.4/modules.softdep

@@ -0,0 +1 @@
+# Soft dependencies extracted from modules themselves.

testsuite/rootfs-pristine/test-modprobe/weakdep-loop/lib/modules/4.4.4/modules.symbols

@@ -0,0 +1,3 @@
+# Aliases for symbols, used by symbol_request().
+alias symbol:printB mod_loop_b
+alias symbol:printA mod_loop_a

testsuite/rootfs-pristine/test-modprobe/weakdep-loop/lib/modules/4.4.4/modules.weakdep

@@ -0,0 +1 @@
+# Weak dependencies extracted from modules themselves.

testsuite/rootfs-pristine/test-user/correct-weakdep.txt

@@ -0,0 +1,2 @@
+mod-loop-b: mod_loop_a mod_simple
+mod-weakdep: mod_simple

testsuite/rootfs-pristine/test-user/etc/modprobe.d/dumb-weakdep.conf

@@ -0,0 +1 @@
+weakdep mod-loop-b mod-loop-a mod-simple

testsuite/rootfs-pristine/test-user/lib/modules/4.4.4/modules.alias

@@ -0,0 +1 @@
+# Aliases extracted from modules themselves.

testsuite/rootfs-pristine/test-user/lib/modules/4.4.4/modules.dep

@@ -0,0 +1,4 @@
+kernel/mod-weakdep.ko:
+kernel/mod-simple.ko:
+kernel/mod-loop-b.ko:
+kernel/mod-loop-a.ko: kernel/mod-loop-b.ko

testsuite/rootfs-pristine/test-user/lib/modules/4.4.4/modules.softdep

@@ -0,0 +1 @@
+# Soft dependencies extracted from modules themselves.

testsuite/rootfs-pristine/test-user/lib/modules/4.4.4/modules.symbols

@@ -0,0 +1,3 @@
+# Aliases for symbols, used by symbol_request().
+alias symbol:printB mod_loop_b
+alias symbol:printA mod_loop_a

testsuite/rootfs-pristine/test-user/lib/modules/4.4.4/modules.weakdep

@@ -0,0 +1,2 @@
+# Weak dependencies extracted from modules themselves.
+weakdep mod_weakdep mod-simple

testsuite/setup-rootfs.sh

@@ -68,6 +68,8 @@ map=(
     ["test-depmod/search-order-external-last/lib/modules/external/"]="mod-simple.ko"
     ["test-depmod/search-order-override$MODULE_DIRECTORY/4.4.4/foo/"]="mod-simple.ko"
     ["test-depmod/search-order-override$MODULE_DIRECTORY/4.4.4/override/"]="mod-simple.ko"
+    ["test-depmod/check-weakdep$MODULE_DIRECTORY/4.4.4/kernel/mod-weakdep.ko"]="mod-weakdep.ko"
+    ["test-depmod/check-weakdep$MODULE_DIRECTORY/4.4.4/kernel/mod-simple.ko"]="mod-simple.ko"
     ["test-dependencies$MODULE_DIRECTORY/4.0.20-kmod/kernel/fs/foo/"]="mod-foo-b.ko"
     ["test-dependencies$MODULE_DIRECTORY/4.0.20-kmod/kernel/"]="mod-foo-c.ko"
     ["test-dependencies$MODULE_DIRECTORY/4.0.20-kmod/kernel/lib/"]="mod-foo-a.ko"
@@ -80,6 +82,9 @@ map=(
     ["test-modprobe/show-exports/mod-loop-a.ko"]="mod-loop-a.ko"
     ["test-modprobe/softdep-loop$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-a.ko"]="mod-loop-a.ko"
     ["test-modprobe/softdep-loop$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-b.ko"]="mod-loop-b.ko"
+    ["test-modprobe/weakdep-loop$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-a.ko"]="mod-loop-a.ko"
+    ["test-modprobe/weakdep-loop$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-b.ko"]="mod-loop-b.ko"
+    ["test-modprobe/weakdep-loop$MODULE_DIRECTORY/4.4.4/kernel/mod-simple.ko"]="mod-simple.ko"
     ["test-modprobe/install-cmd-loop$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-a.ko"]="mod-loop-a.ko"
     ["test-modprobe/install-cmd-loop$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-b.ko"]="mod-loop-b.ko"
     ["test-modprobe/force$MODULE_DIRECTORY/4.4.4/kernel/"]="mod-simple.ko"
@@ -103,6 +108,10 @@ map=(
     ["test-modinfo/mod-simple-sha256.ko"]="mod-simple.ko"
     ["test-modinfo/mod-simple-pkcs7.ko"]="mod-simple.ko"
     ["test-modinfo/external/lib/modules/external/mod-simple.ko"]="mod-simple.ko"
+    ["test-user$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-a.ko"]="mod-loop-a.ko"
+    ["test-user$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-b.ko"]="mod-loop-b.ko"
+    ["test-user$MODULE_DIRECTORY/4.4.4/kernel/mod-simple.ko"]="mod-simple.ko"
+    ["test-user$MODULE_DIRECTORY/4.4.4/kernel/mod-weakdep.ko"]="mod-weakdep.ko"
 )
 
 gzip_array=(

testsuite/test-depmod.c

@@ -244,4 +244,31 @@ DEFINE_TEST(depmod_search_order_override,
 		},
 	});
 
+#define CHECK_WEAKDEP_ROOTFS TESTSUITE_ROOTFS "test-depmod/check-weakdep"
+#define CHECK_WEAKDEP_LIB_MODULES CHECK_WEAKDEP_ROOTFS MODULE_DIRECTORY "/" MODULES_UNAME
+static noreturn int depmod_check_weakdep(const struct test *t)
+{
+	const char *progname = ABS_TOP_BUILDDIR "/tools/depmod";
+	const char *const args[] = {
+		progname,
+		NULL,
+	};
+
+	test_spawn_prog(progname, args);
+	exit(EXIT_FAILURE);
+}
+DEFINE_TEST(depmod_check_weakdep,
+	.description = "check weakdep output",
+	.config = {
+		[TC_UNAME_R] = MODULES_UNAME,
+		[TC_ROOTFS] = CHECK_WEAKDEP_ROOTFS,
+	},
+	.output = {
+		.files = (const struct keyval[]) {
+			{ CHECK_WEAKDEP_LIB_MODULES "/correct-modules.weakdep",
+			  CHECK_WEAKDEP_LIB_MODULES "/modules.weakdep" },
+			{ }
+		},
+	});
+
 TESTSUITE_MAIN();

testsuite/test-modprobe.c

@@ -181,6 +181,29 @@ DEFINE_TEST(modprobe_softdep_loop,
 	.modules_loaded = "mod-loop-a,mod-loop-b",
 	);
 
+static noreturn int modprobe_weakdep_loop(const struct test *t)
+{
+	const char *progname = ABS_TOP_BUILDDIR "/tools/modprobe";
+	const char *const args[] = {
+		progname,
+		"mod-loop-b",
+		NULL,
+	};
+
+	test_spawn_prog(progname, args);
+	exit(EXIT_FAILURE);
+}
+DEFINE_TEST(modprobe_weakdep_loop,
+	.description = "check if modprobe breaks weakdep loop",
+	.config = {
+		[TC_UNAME_R] = "4.4.4",
+		[TC_ROOTFS] = TESTSUITE_ROOTFS "test-modprobe/weakdep-loop",
+		[TC_INIT_MODULE_RETCODES] = "",
+	},
+	.modules_loaded = "mod-loop-b",
+	.modules_not_loaded = "mod-loop-a,mod-simple-c",
+	);
+
 static noreturn int modprobe_install_cmd_loop(const struct test *t)
 {
 	const char *progname = ABS_TOP_BUILDDIR "/tools/modprobe";

testsuite/test-user.c

@@ -0,0 +1,110 @@
+/*
+ * Copyright Red Hat
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <errno.h>
+#include <inttypes.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <libkmod/libkmod.h>
+
+#include "testsuite.h"
+
+#define TEST_USER_ROOTFS TESTSUITE_ROOTFS "test-user/"
+#define TEST_USER_KERNEL_DIR TEST_USER_ROOTFS "lib/modules/4.4.4/"
+
+static const char *const test_user_config_paths[] = {
+	TEST_USER_ROOTFS "etc/modprobe.d",
+	NULL
+};
+
+static const char *const mod_name[] = {
+	"mod-loop-b",
+	"mod-weakdep",
+	NULL
+};
+
+static int test_user_weakdep(const struct test *t)
+{
+	struct kmod_ctx *ctx;
+	int mod_name_index = 0;
+	int err;
+
+	ctx = kmod_new(TEST_USER_KERNEL_DIR, test_user_config_paths);
+	if (ctx == NULL)
+		exit(EXIT_FAILURE);
+
+	while (mod_name[mod_name_index]) {
+		struct kmod_list *list = NULL;
+		struct kmod_module *mod = NULL;
+		struct kmod_list *mod_list = NULL;
+		struct kmod_list *itr = NULL;
+
+		printf("%s:", mod_name[mod_name_index]);
+		err = kmod_module_new_from_lookup(ctx, mod_name[mod_name_index], &list);
+		if (list == NULL || err < 0) {
+			fprintf(stderr, "module %s not found in directory %s\n",
+				mod_name[mod_name_index],
+				ctx ? kmod_get_dirname(ctx) : "(missing)");
+			exit(EXIT_FAILURE);
+		}
+
+		mod = kmod_module_get_module(list);
+
+		err = kmod_module_get_weakdeps(mod, &mod_list);
+		if (err) {
+			fprintf(stderr, "weak dependencies can not be read for %s (%d)\n",
+				mod_name[mod_name_index], err);
+			exit(EXIT_FAILURE);
+		}
+
+		kmod_list_foreach(itr, mod_list) {
+			struct kmod_module *weakdep_mod = kmod_module_get_module(itr);
+			const char *weakdep_name = kmod_module_get_name(weakdep_mod);
+
+			printf(" %s", weakdep_name);
+			kmod_module_unref(weakdep_mod);
+		}
+		printf("\n");
+
+		kmod_module_unref_list(mod_list);
+		kmod_module_unref(mod);
+		kmod_module_unref_list(list);
+
+		mod_name_index++;
+	}
+
+	kmod_unref(ctx);
+
+	return EXIT_SUCCESS;
+}
+DEFINE_TEST(test_user_weakdep,
+	.description = "check if modprobe breaks weakdep2",
+	.config = {
+		[TC_UNAME_R] = "4.4.4",
+		[TC_ROOTFS] = TESTSUITE_ROOTFS "test-user",
+		[TC_INIT_MODULE_RETCODES] = "",
+	},
+	.need_spawn = true,
+	.output = {
+		.out = TESTSUITE_ROOTFS "test-user/correct-weakdep.txt",
+	});
+
+TESTSUITE_MAIN();

testsuite/testsuite.c

@@ -773,10 +773,10 @@ static int cmp_modnames(const void *m1, const void *m2)
 }
 
 /*
- * Store the expected module names in buf and return a list of pointers to
- * them.
+ * Auxiliary function to store the module names in buf and return a list
+ * of pointers to them.
  */
-static const char **read_expected_modules(const struct test *t,
+static const char **read_modules(const char* modules,
 		char **buf, int *count)
 {
 	const char **res;
@@ -784,12 +784,8 @@ static const char **read_expected_modules(const struct test *t,
 	int i;
 	char *p;
 
-	if (t->modules_loaded[0] == '\0') {
-		*count = 0;
-		*buf = NULL;
-		return NULL;
-	}
-	*buf = strdup(t->modules_loaded);
+
+	*buf = strdup(modules);
 	if (!*buf) {
 		*count = -1;
 		return NULL;
@@ -817,6 +813,36 @@ static const char **read_expected_modules(const struct test *t,
 	return res;
 }
 
+/*
+ * 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)
+{
+	if (t->modules_loaded[0] == '\0') {
+		*count = 0;
+		*buf = NULL;
+		return NULL;
+	}
+	return read_modules(t->modules_loaded, buf, count);
+}
+
+/*
+ * Store the unexpected module names in buf and return a list of pointers to
+ * them.
+ */
+static const char **read_unexpected_modules(const struct test *t,
+		char **buf, int *count)
+{
+	if (t->modules_not_loaded[0] == '\0') {
+		*count = 0;
+		*buf = NULL;
+		return NULL;
+	}
+	return read_modules(t->modules_not_loaded, buf, count);
+}
+
 static char **read_loaded_modules(const struct test *t, char **buf, int *count)
 {
 	char dirname[PATH_MAX];
@@ -931,6 +957,54 @@ out_a1:
 	return err;
 }
 
+static int check_not_loaded_modules(const struct test *t)
+{
+	int l1, l2, i1, i2;
+	const char **a1;
+	char **a2;
+	char *buf1, *buf2;
+	int err = false;
+
+	a1 = read_unexpected_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) {
+			err = false;
+			ERR("module %s loaded\n", a1[i1]);
+			i1++;
+		} else if (cmp < 0) {
+			i1++;
+			i2++;
+		} 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)
 {
@@ -995,6 +1069,8 @@ static inline int test_run_parent(const struct test *t, int fdout[2],
 		match_modules = check_loaded_modules(t);
 	else
 		match_modules = true;
+	if (match_modules && t->modules_not_loaded)
+		match_modules = check_not_loaded_modules(t);
 
 	if (t->expected_fail == false) {
 		if (err == 0) {

testsuite/testsuite.h

@@ -103,6 +103,7 @@ struct test {
 	} output;
 	/* comma-separated list of loaded modules at the end of the test */
 	const char *modules_loaded;
+	const char *modules_not_loaded;
 	testfunc func;
 	const char *config[_TC_LAST];
 	const char *path;