Add utime07 test

This test has been extracted from symlink01 test and it verifies that
utime() is working correctly on symlink() generated files.

Link: https://lore.kernel.org/ltp/20240503085242.22677-1-andrea.cervesato@suse.de/
Reviewed-by: Avinesh Kumar <akumar@suse.de>
Reviewed-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>
[ pvorel: extend doc ]
Signed-off-by: Petr Vorel <pvorel@suse.cz>

Author: acerv

runtest/smoketest

@@ -9,7 +9,7 @@ wait02 wait02
 write01 write01
 symlink01 symlink01
 stat04 symlink01 -T stat04
-utime01A symlink01 -T utime01
+utime07 utime07
 rename01A symlink01 -T rename01
 splice02 splice02 -s 20
 df01_sh df01.sh

runtest/syscalls

@@ -1677,12 +1677,12 @@ ustat01 ustat01
 ustat02 ustat02
 
 utime01 utime01
-utime01A symlink01 -T utime01
 utime02 utime02
 utime03 utime03
 utime04 utime04
 utime05 utime05
 utime06 utime06
+utime07 utime07
 
 utimes01 utimes01
 

testcases/kernel/syscalls/utime/.gitignore

@@ -4,3 +4,4 @@
 /utime04
 /utime05
 /utime06
+/utime07

testcases/kernel/syscalls/utime/utime07.c

@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2000 Silicon Graphics, Inc.  All Rights Reserved.
+ * Authors: David Fenner, Jon Hendrickson
+ * Copyright (C) 2024 Andrea Cervesato <andrea.cervesato@suse.com>
+ */
+
+/*\
+ * [Description]
+ *
+ * This test verifies that utime() is working correctly on symlink()
+ * generated files.
+ *
+ * Also verify if utime() fails:
+ *
+ * - ENOENT when symlink points to nowhere
+ * - ELOOP when symlink is looping
+ */
+
+#include <utime.h>
+#include "tst_test.h"
+
+#define TIME_DIFF 100
+
+static void create_symlink(const char *path, const char *symname)
+{
+	struct stat asymlink;
+
+	SAFE_SYMLINK(path, symname);
+	SAFE_LSTAT(symname, &asymlink);
+
+	if ((asymlink.st_mode & S_IFMT) != S_IFLNK) {
+		tst_brk(TBROK, "symlink generated a non-symbolic link %s to %s",
+			symname, path);
+	}
+}
+
+static void test_utime(void)
+{
+	char *symname = "my_symlink0";
+	struct stat oldsym_stat;
+	struct stat newsym_stat;
+
+	tst_res(TINFO, "Test if utime() changes access time");
+
+	create_symlink(tst_get_tmpdir(), symname);
+	SAFE_STAT(symname, &oldsym_stat);
+
+	struct utimbuf utimes = {
+		.actime = oldsym_stat.st_atime + TIME_DIFF,
+		.modtime = oldsym_stat.st_mtime + TIME_DIFF
+	};
+
+	TST_EXP_PASS(utime(symname, &utimes));
+	SAFE_STAT(symname, &newsym_stat);
+
+	TST_EXP_EQ_LI(newsym_stat.st_atime - oldsym_stat.st_atime, TIME_DIFF);
+	TST_EXP_EQ_LI(newsym_stat.st_mtime - oldsym_stat.st_mtime, TIME_DIFF);
+
+	SAFE_UNLINK(symname);
+}
+
+static void test_utime_no_path(void)
+{
+	char *symname = "my_symlink1";
+	struct utimbuf utimes;
+
+	tst_res(TINFO, "Test if utime() raises ENOENT when symlink points to nowhere");
+
+	create_symlink("bc+eFhi!k", symname);
+	TST_EXP_FAIL(utime(symname, &utimes), ENOENT);
+
+	SAFE_UNLINK(symname);
+}
+
+static void test_utime_loop(void)
+{
+	char *symname = "my_symlink2";
+	struct utimbuf utimes;
+
+	tst_res(TINFO, "Test if utime() raises ELOOP when symlink is looping");
+
+	create_symlink(symname, symname);
+	TST_EXP_FAIL(utime(symname, &utimes), ELOOP);
+
+	SAFE_UNLINK(symname);
+}
+
+static void run(void)
+{
+	test_utime();
+	test_utime_no_path();
+	test_utime_loop();
+}
+
+static struct tst_test test = {
+	.test_all = run,
+	.needs_tmpdir = 1,
+};