eal/unix: fix firmware reading with external xz helper

[ upstream commit 39970abcf4850e070aa4709c87bcac15cb27caf8 ]

libarchive may support xz decompression only through an
external (slower) helper.

In such a case, archive_read_support_filter_xz() returns
ARCHIVE_WARN.

Fixes: 40edb9c ("eal: handle compressed firmware")

Signed-off-by: Srikanth Yalavarthi <syalavarthi@marvell.com>
Reviewed-by: David Marchand <david.marchand@redhat.com>

lib/eal/unix/eal_firmware.c

@@ -25,19 +25,31 @@ static int
 firmware_open(struct firmware_read_ctx *ctx, const char *name, size_t blocksize)
 {
 	struct archive_entry *e;
+	int err;
 
 	ctx->a = archive_read_new();
 	if (ctx->a == NULL)
 		return -1;
-	if (archive_read_support_format_raw(ctx->a) != ARCHIVE_OK ||
-			archive_read_support_filter_xz(ctx->a) != ARCHIVE_OK ||
-			archive_read_open_filename(ctx->a, name, blocksize) != ARCHIVE_OK ||
-			archive_read_next_header(ctx->a, &e) != ARCHIVE_OK) {
-		archive_read_free(ctx->a);
-		ctx->a = NULL;
-		return -1;
-	}
+
+	if (archive_read_support_format_raw(ctx->a) != ARCHIVE_OK)
+		goto error;
+
+	err = archive_read_support_filter_xz(ctx->a);
+	if (err != ARCHIVE_OK && err != ARCHIVE_WARN)
+		goto error;
+
+	if (archive_read_open_filename(ctx->a, name, blocksize) != ARCHIVE_OK)
+		goto error;
+
+	if (archive_read_next_header(ctx->a, &e) != ARCHIVE_OK)
+		goto error;
+
 	return 0;
+
+error:
+	archive_read_free(ctx->a);
+	ctx->a = NULL;
+	return -1;
 }
 
 static ssize_t