[LTP] [PATCH v3 2/2] open: replace getdtablesize with getrlimit

[Jinseok Kim]

The test currently uses getdtablesize() to determine the maximum
number of file descriptors for the process. This interface is
considered legacy and is not specified by POSIX.

Use getrlimit() instead, which provides a well-defined
and portable way to obtain the per-process file descriptor limit.

Signed-off-by: Jinseok Kim <always.starving0@gmail.com>
---
 testcases/kernel/syscalls/open/open04.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/testcases/kernel/syscalls/open/open04.c b/testcases/kernel/syscalls/open/open04.c
index 152bec2d4..9c5634ba9 100644
--- a/testcases/kernel/syscalls/open/open04.c
+++ b/testcases/kernel/syscalls/open/open04.c
@@ -11,6 +11,7 @@

 #include <stdio.h>
 #include <stdlib.h>
+#include <sys/resource.h>
 #include "tst_test.h"

 #define FNAME "open04"
@@ -23,8 +24,10 @@ static char fname[20];
 static void setup(void)
 {
 	int fd;
+	struct rlimit rlim;

-	fds_limit = getdtablesize();
+	SAFE_GETRLIMIT(RLIMIT_NOFILE, &rlim);
+	fds_limit = rlim.rlim_cur;
 	first = SAFE_OPEN(FNAME, O_RDWR | O_CREAT, 0777);

 	fds = SAFE_MALLOC(sizeof(int) * (fds_limit - first));
--
2.43.0