[PATCH 5.5 172/367] selftests: bpf: Use a temporary file in test_sockmap

[Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>]

From: Lorenz Bauer <lmb@xxxxxxxxxxxxxx>

commit c31dbb1e41d1857b403f9bf58c87f5898519a0bc upstream.

Use a proper temporary file for sendpage tests. This means that running
the tests doesn't clutter the working directory, and allows running the
test on read-only filesystems.

Fixes: 16962b2404ac ("bpf: sockmap, add selftests")
Signed-off-by: Lorenz Bauer <lmb@xxxxxxxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Reviewed-by: Jakub Sitnicki <jakub@xxxxxxxxxxxxxx>
Acked-by: Martin KaFai Lau <kafai@xxxxxx>
Acked-by: John Fastabend <john.fastabend@xxxxxxxxx>
Link: https://lore.kernel.org/bpf/20200124112754.19664-2-lmb@xxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 tools/testing/selftests/bpf/test_sockmap.c |   15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

--- a/tools/testing/selftests/bpf/test_sockmap.c
+++ b/tools/testing/selftests/bpf/test_sockmap.c
@@ -331,7 +331,7 @@ static int msg_loop_sendpage(int fd, int
 	FILE *file;
 	int i, fp;
 
-	file = fopen(".sendpage_tst.tmp", "w+");
+	file = tmpfile();
 	if (!file) {
 		perror("create file for sendpage");
 		return 1;
@@ -340,13 +340,8 @@ static int msg_loop_sendpage(int fd, int
 		fwrite(&k, sizeof(char), 1, file);
 	fflush(file);
 	fseek(file, 0, SEEK_SET);
-	fclose(file);
 
-	fp = open(".sendpage_tst.tmp", O_RDONLY);
-	if (fp < 0) {
-		perror("reopen file for sendpage");
-		return 1;
-	}
+	fp = fileno(file);
 
 	clock_gettime(CLOCK_MONOTONIC, &s->start);
 	for (i = 0; i < cnt; i++) {
@@ -354,11 +349,11 @@ static int msg_loop_sendpage(int fd, int
 
 		if (!drop && sent < 0) {
 			perror("send loop error");
-			close(fp);
+			fclose(file);
 			return sent;
 		} else if (drop && sent >= 0) {
 			printf("sendpage loop error expected: %i\n", sent);
-			close(fp);
+			fclose(file);
 			return -EIO;
 		}
 
@@ -366,7 +361,7 @@ static int msg_loop_sendpage(int fd, int
 			s->bytes_sent += sent;
 	}
 	clock_gettime(CLOCK_MONOTONIC, &s->end);
-	close(fp);
+	fclose(file);
 	return 0;
 }