Open directories O_RDONLY for fsync, add debugging if it fails

2 files changed, 9 insertions, 4 deletions

diff --git a/gensignkey.c b/gensignkey.c
index 06fdfd3..e6c40e0 100644
--- a/gensignkey.c
+++ b/gensignkey.c
@@ -41,7 +41,9 @@ static int buf_writefile(buffer * buf, const char * filename) {
 
 out:
 	if (fd >= 0) {
-		fsync(fd);
+		if (fsync(fd) != 0) {
+			dropbear_log(LOG_ERR, "fsync of %s failed: %s", filename, strerror(errno));
+		}
 		m_close(fd);
 	}
 	return ret;
diff --git a/svr-kex.c b/svr-kex.c
index 01c76e6..6cc5433 100644
--- a/svr-kex.c
+++ b/svr-kex.c
@@ -91,12 +91,15 @@ static void fsync_parent_dir(const char* fn) {
 #ifdef HAVE_LIBGEN_H
 	char *fn_dir = m_strdup(fn);
 	char *dir = dirname(fn_dir);
-	/* some OSes need the fd to be writable for fsync */
-	int dirfd = open(dir, O_RDWR);
+	int dirfd = open(dir, O_RDONLY);
 
 	if (dirfd != -1) {
-		fsync(dirfd);
+		if (fsync(dirfd) != 0) {
+			TRACE(("fsync of directory %s failed: %s", dir, strerror(errno)))
+		}
 		m_close(dirfd);
+	} else {
+		TRACE(("error opening directory %s for fsync: %s", dir, strerror(errno)))
 	}
 
 	free(fn_dir);