syscalls/statx05: add mkfs.ext4 package version check

The encryption feature was added in e2fsprogs 1.43:
  e2fsprogs (1.43~WIP.2015.05.18-1) unstable; urgency=low
    * Add support for file encryption feature

The test should be skipped when running with older package, otherwise
it will fail with:
  Invalid filesystem option set: encrypt

Use popen and fscanf to get mkfs.ext4 -V output for version
comparison. This version checking by adding digits together does not
work with alphabets in the number like rc1, but in that case the test
will still be tested.

It will now be skipped with (Tested with Ubuntu Xenial + 4.15 kernel):
  statx05.c:102: TCONF: Test needs mkfs.ext4 >= 1.43 for encrypt option, test skipped

Fixes: #542
Signed-off-by: Po-Hsu Lin <[email protected]>
Reviewed-by: Cyril Hrubis <[email protected]>

testcases/kernel/syscalls/statx/statx05.c

@@ -17,13 +17,15 @@
  * Second directory has no flags set.
  *
  * Minimum kernel version required is 4.11.
+ * Minimum e2fsprogs version required is 1.43.
  */
 
 #define _GNU_SOURCE
 #include <stdlib.h>
 #include <stdio.h>
 #include <sys/types.h>
 #include <sys/wait.h>
+#include "tst_safe_stdio.h"
 #include "tst_test.h"
 #include "lapi/fs.h"
 #include "lapi/stat.h"
@@ -86,9 +88,18 @@ static void run(unsigned int i)
 
 static void setup(void)
 {
+	FILE *f;
 	char opt_bsize[32];
 	const char *const fs_opts[] = {"-O encrypt", opt_bsize, NULL};
-	int ret;
+	int ret, rc, major, minor, patch;
+
+	f = SAFE_POPEN("mkfs.ext4 -V 2>&1", "r");
+	rc = fscanf(f, "mke2fs %d.%d.%d", &major, &minor, &patch);
+	if (rc != 3)
+		tst_res(TWARN, "Unable parse version number");
+	else if (major * 10000 + minor * 100 + patch < 14300)
+		tst_brk(TCONF, "Test needs mkfs.ext4 >= 1.43 for encrypt option, test skipped");
+	pclose(f);
 
 	snprintf(opt_bsize, sizeof(opt_bsize), "-b %i", getpagesize());