Add more testcases in mkdir03

We add more test cases in mkdir03 in order to check that mkdir()
can't overwrite certain types of files, such as symlinks, directories,
pipes, devices, etc.
These test cases come from symlink01 refactoring.

Link: https://lore.kernel.org/ltp/[email protected]/
Reviewed-by: Cyril Hrubis <[email protected]>
Reviewed-by: Petr Vorel <[email protected]>
Signed-off-by: Andrea Cervesato <[email protected]>

runtest/syscalls

@@ -757,7 +757,6 @@ mkdir02 mkdir02
 mkdir03 mkdir03
 mkdir04 mkdir04
 mkdir05 mkdir05
-mkdir05A symlink01 -T mkdir05
 mkdir09 mkdir09
 
 #mkdirat test cases

testcases/kernel/syscalls/mkdir/mkdir03.c

@@ -9,6 +9,8 @@
  *	EFAULT, ENAMETOOLONG, EEXIST, ENOENT, ENOTDIR, ELOOP and EROFS
  */
 
+#include <paths.h>
+#include <stdlib.h>
 #include <errno.h>
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -19,6 +21,10 @@
 #include "tst_test.h"
 
 #define TST_EEXIST	"tst_eexist"
+#define TST_PIPE	"tst_pipe"
+#define TST_FOLDER	"tst_folder"
+#define TST_SYMLINK	"tst_symlink"
+#define TST_NULLDEV	_PATH_DEVNULL
 #define TST_ENOENT	"tst_enoent/tst"
 #define TST_ENOTDIR_FILE "tst_enotdir"
 #define TST_ENOTDIR_DIR	"tst_enotdir/tst"
@@ -41,6 +47,10 @@ static struct tcase {
 	{NULL, EFAULT},
 	{long_dir, ENAMETOOLONG},
 	{TST_EEXIST, EEXIST},
+	{TST_FOLDER, EEXIST},
+	{TST_PIPE, EEXIST},
+	{TST_SYMLINK, EEXIST},
+	{TST_NULLDEV, EEXIST},
 	{TST_ENOENT, ENOENT},
 	{TST_ENOTDIR_DIR, ENOTDIR},
 	{loop_dir, ELOOP},
@@ -70,7 +80,13 @@ static void verify_mkdir(unsigned int n)
 static void setup(void)
 {
 	unsigned int i;
+	char *tmpdir = tst_get_tmpdir();
 
+	SAFE_SYMLINK(tmpdir, TST_SYMLINK);
+	free(tmpdir);
+
+	SAFE_MKFIFO(TST_PIPE, 0777);
+	SAFE_MKDIR(TST_FOLDER, 0777);
 	SAFE_TOUCH(TST_EEXIST, MODE, NULL);
 	SAFE_TOUCH(TST_ENOTDIR_FILE, MODE, NULL);