[ovs-dev] [PATCH v2] ovsdb-client: Set binary on FDs when doing backup/restore

[Alin Gabriel Serdean]

Add some needed consitentcy on Windows for STD_IN/OUT file descriptors
when doing backup and restore.

Reported-at:https://mail.openvswitch.org/pipermail/ovs-dev/2018-January/343518.html
Suggested-by: Ben Pfaff <blp at ovn.org>
Signed-off-by: Alin Gabriel Serdean <aserdean at ovn.org>
---
 ovsdb/ovsdb-client.c | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/ovsdb/ovsdb-client.c b/ovsdb/ovsdb-client.c
index 222bd6ca8..3a0cb3d63 100644
--- a/ovsdb/ovsdb-client.c
+++ b/ovsdb/ovsdb-client.c
@@ -18,6 +18,7 @@
 
 #include <ctype.h>
 #include <errno.h>
+#include <fcntl.h>
 #include <getopt.h>
 #include <limits.h>
 #include <signal.h>
@@ -1475,11 +1476,32 @@ print_and_free_log_record(struct json *record)
     json_destroy(record);
 }
 
+/* Wrapper to verify if the file descriptor `fd` refers to a terminal.
+ * On Windows also set binary mode on the file descriptor to avoid
+ * translation (i.e. CRLF line endings). */
+static bool
+check_and_set_stdout(int fd)
+{
+    if (isatty(fd)) {
+        return false;
+    }
+#ifdef _WIN32
+    if (fd == STDOUT_FILENO) {
+        fflush(stdout);
+    }
+    int result = _setmode(fd, O_BINARY);
+    if (result == -1) {
+        ovs_fatal(0, "could not _setmode O_BINARY on fd");
+    }
+#endif
+    return true;
+}
+
 static void
 do_backup(struct jsonrpc *rpc, const char *database,
           int argc OVS_UNUSED, char *argv[] OVS_UNUSED)
 {
-    if (isatty(STDOUT_FILENO)) {
+    if (!check_and_set_stdout(STDOUT_FILENO)) {
         ovs_fatal(0, "not writing backup to a terminal; "
                   "please redirect stdout to a file");
     }
@@ -1595,7 +1617,7 @@ static void
 do_restore(struct jsonrpc *rpc, const char *database,
            int argc OVS_UNUSED, char *argv[] OVS_UNUSED)
 {
-    if (isatty(STDIN_FILENO)) {
+    if (!check_and_set_stdout(STDIN_FILENO)) {
         ovs_fatal(0, "not reading backup from a terminal; "
                   "please redirect stdin from a file");
     }
-- 
2.16.1.windows.1