[LTP] [PATCH v2] unshare03: set nr_open with sizeof(long)*8

[lufei]

Set nr_open with sizeof(long)*8 to trigger EMFILE, instead of reading
number of filedescriptors limit.

Signed-off-by: lufei <lufei@uniontech.com>
---
 testcases/kernel/syscalls/unshare/unshare03.c | 23 ++-----------------
 1 file changed, 2 insertions(+), 21 deletions(-)

diff --git a/testcases/kernel/syscalls/unshare/unshare03.c b/testcases/kernel/syscalls/unshare/unshare03.c
index 7c5e71c4e..c3b98930d 100644
--- a/testcases/kernel/syscalls/unshare/unshare03.c
+++ b/testcases/kernel/syscalls/unshare/unshare03.c
@@ -17,44 +17,25 @@
 #include "lapi/sched.h"
 
 #define FS_NR_OPEN "/proc/sys/fs/nr_open"
-#define NR_OPEN_LIMIT 1024
-#define NR_OPEN_DUP 64
 
 #ifdef HAVE_UNSHARE
 
 static void run(void)
 {
-	int nr_open;
-	int nr_limit;
-	struct rlimit rlimit;
 	struct tst_clone_args args = {
 		.flags = CLONE_FILES,
 		.exit_signal = SIGCHLD,
 	};
 
-	SAFE_FILE_SCANF(FS_NR_OPEN, "%d", &nr_open);
-	tst_res(TDEBUG, "Maximum number of file descriptors: %d", nr_open);
+	int nr_open = sizeof(long) * 8;
 
-	nr_limit = nr_open + NR_OPEN_LIMIT;
-	SAFE_FILE_PRINTF(FS_NR_OPEN, "%d", nr_limit);
-
-	SAFE_GETRLIMIT(RLIMIT_NOFILE, &rlimit);
-
-	rlimit.rlim_cur = nr_limit;
-	rlimit.rlim_max = nr_limit;
-
-	SAFE_SETRLIMIT(RLIMIT_NOFILE, &rlimit);
-	tst_res(TDEBUG, "Set new maximum number of file descriptors to : %d",
-		nr_limit);
-
-	SAFE_DUP2(2, nr_open + NR_OPEN_DUP);
+	SAFE_DUP2(2, nr_open + 1);
 
 	if (!SAFE_CLONE(&args)) {
 		SAFE_FILE_PRINTF(FS_NR_OPEN, "%d", nr_open);
 		TST_EXP_FAIL(unshare(CLONE_FILES), EMFILE);
 		exit(0);
 	}
-
 }
 
 static void setup(void)
-- 
2.39.3