lib: tst_module: add library functions for kernel modules

There are new functions: tst_module_exists(), tst_module_load() and
tst_module_unload(). These functions help to load and unload kernel
modules in the tests.

Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Acked-by: Cyril Hrubis <chrubis@suse.cz>
Reviewed-by: Caspar Zhang <caspar@casparzhang.com>
Reviewed-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
diff --git a/include/tst_module.h b/include/tst_module.h
new file mode 100644
index 0000000..c50efec
--- /dev/null
+++ b/include/tst_module.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2013 Oracle and/or its affiliates. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Author:
+ * Alexey Kodanev <alexey.kodanev@oracle.com>
+ *
+ * These functions help to load and unload kernel modules in the tests.
+ *
+ * tst_module_load function already includes tst_module_exists function,
+ * which is checking the following possible module's locations:
+ *
+ * 1. Current working directory
+ *
+ * 2. LTP installation path (using env LTPROOT, which is usually /opt/ltp)
+ *
+ * 3. If tmp directory created, it'll look at the test start working directory
+ *
+ */
+
+#ifndef TST_MODULE
+#define TST_MODULE
+
+/*
+ * Check module existence.
+ *
+ * @mod_name: module's file name.
+ * @mod_path: if it is not NULL, then tst_module_exists places the found
+ * module's path into the location pointed to by *mod_path. It must be freed
+ * with free() when it is no longer needed.
+ *
+ * In case of failure, test'll call cleanup_fn and exit with TCONF return value.
+ */
+void tst_module_exist(void (cleanup_fn)(void), const char *mod_name,
+	char **mod_path);
+
+/*
+ * Load a module using insmod program.
+ *
+ * @mod_name: module's file name.
+ * @argv: an array of pointers to null-terminated strings that represent the
+ * additional parameters to the module. The array of pointers  must be
+ * terminated by a NULL pointer. If argv points to NULL, it will be ignored.
+ *
+ * In case of insmod failure, test will call cleanup_fn and exit with TBROK
+ * return value.
+ */
+void tst_module_load(void (cleanup_fn)(void),
+	const char *mod_name, char *const argv[]);
+
+/*
+ * Unload a module using rmmod program. In case of failure, test will call
+ * cleanup_fn and exit with TBROK return value.
+ *
+ * @mod_name: can be module name or module's file name.
+ */
+void tst_module_unload(void (cleanup_fn)(void), const char *mod_name);
+
+#endif /* TST_MODULE */
diff --git a/lib/tst_module.c b/lib/tst_module.c
new file mode 100644
index 0000000..832da27
--- /dev/null
+++ b/lib/tst_module.c
@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2013 Oracle and/or its affiliates. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Author: Alexey Kodanev <alexey.kodanev@oracle.com>
+ *
+ */
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "test.h"
+#include "ltp_priv.h"
+#include "tst_module.h"
+
+void tst_module_exists(void (cleanup_fn)(void),
+	const char *mod_name, char **mod_path)
+{
+	/* check current working directory */
+	if (access(mod_name, F_OK) == 0) {
+		if (mod_path != NULL)
+			*mod_path = strdup(mod_name);
+		return;
+	}
+	char *buf = NULL;
+	int err = -1;
+	/* check LTP installation path */
+	const char *ltproot = getenv("LTPROOT");
+	if (ltproot != NULL) {
+		if (asprintf(&buf, "%s/testcases/bin/%s",
+			ltproot, mod_name) == -1) {
+			tst_brkm(TBROK | TERRNO, cleanup_fn,
+				"asprintf failed at %s:%d",
+				__FILE__, __LINE__);
+		}
+		err = access(buf, F_OK);
+	}
+	/* check start working directory */
+	if (err == -1 && tst_tmpdir_created()) {
+		free(buf);
+		if (asprintf(&buf, "%s/%s", tst_get_startwd(),
+			mod_name) == -1) {
+			tst_brkm(TBROK | TERRNO, cleanup_fn,
+				"asprintf failed at %s:%d",
+				__FILE__, __LINE__);
+		}
+		err = access(buf, F_OK);
+	}
+
+	if (err != 0) {
+		free(buf);
+		tst_brkm(TCONF, cleanup_fn, "Failed to find module '%s'",
+			mod_name);
+	}
+
+	if (mod_path != NULL)
+		*mod_path = buf;
+	else
+		free(buf);
+}
+
+void tst_module_load(void (cleanup_fn)(void),
+	const char *mod_name, char *const argv[])
+{
+	char *mod_path = NULL;
+	tst_module_exists(cleanup_fn, mod_name, &mod_path);
+
+	const int offset = 2; /* command name & module path */
+	int size = 0;
+	while (argv && argv[size])
+		++size;
+	size += offset;
+	char *mod_argv[size + 1]; /* + NULL in the end */
+	mod_argv[size] = NULL;
+	mod_argv[0] = "insmod";
+	mod_argv[1] = mod_path;
+
+	int i;
+	for (i = offset; i < size; ++i)
+		mod_argv[i] = argv[i - offset];
+
+	tst_run_cmd(cleanup_fn, mod_argv);
+	free(mod_path);
+}
+
+void tst_module_unload(void (cleanup_fn)(void), const char *mod_name)
+{
+	char *const argv[] = { "rmmod", mod_name, NULL };
+	tst_run_cmd(cleanup_fn, argv);
+}