selftests/efivarfs: add create-read test

Test that reads from a newly-created efivarfs file (with no data written)
will return EOF.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Lingzhu Xiang <lxiang@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 38 insertions, 0 deletions

diff --git a/tools/testing/selftests/efivarfs/create-read.c b/tools/testing/selftests/efivarfs/create-read.c
new file mode 100644
index 000000000000..7feef1880968
--- /dev/null
+++ b/tools/testing/selftests/efivarfs/create-read.c
@@ -0,0 +1,38 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <string.h>
+
+int main(int argc, char **argv)
+{
+	const char *path;
+	char buf[4];
+	int fd, rc;
+
+	if (argc < 2) {
+		fprintf(stderr, "usage: %s <path>\n", argv[0]);
+		return EXIT_FAILURE;
+	}
+
+	path = argv[1];
+
+	/* create a test variable */
+	fd = open(path, O_RDWR | O_CREAT, 0600);
+	if (fd < 0) {
+		perror("open(O_WRONLY)");
+		return EXIT_FAILURE;
+	}
+
+	rc = read(fd, buf, sizeof(buf));
+	if (rc != 0) {
+		fprintf(stderr, "Reading a new var should return EOF\n");
+		return EXIT_FAILURE;
+	}
+
+	return EXIT_SUCCESS;
+}