Implement proper branches

Trying to implement differing negotiation based on parameters that just
happen to be there is a bad strategy, as this bug demonstrates.

Instead, add a parameter to the negotiate() function that is a bitmask
telling us which part of the negotiation we would like to see: modern vs
oldstyle, initial phase versus 'the rest'.

This doesn't actually survive 'make check' yet, because of a different
bit of crack that's still in there. Different bug, different commit.

diff --git a/nbd-server.c b/nbd-server.c
index f8028cb..e733c3e 100644 (file)
--- a/nbd-server.c
+++ b/nbd-server.c
@@ -165,6 +165,10 @@ char pidfname[256]; /**< name of our PID file */
 char pidftemplate[256]; /**< template to be used for the filename of the PID file */
 char default_authname[] = SYSCONFDIR "/nbd-server/allow"; /**< default name of allow file */
 
+#define NEG_INIT       (1 << 0)
+#define NEG_OLD                (1 << 1)
+#define NEG_MODERN     (1 << 2)
+
 int modernsock=0;        /**< Socket for the modern handler. Not used
                               if a client was only specified on the
                               command line; only port used if
@@ -1361,7 +1365,7 @@ int expflush(CLIENT *client) {
  *
  * @param client The client we're negotiating with.
  **/
-CLIENT* negotiate(int net, CLIENT *client, GArray* servers) {
+CLIENT* negotiate(int net, CLIENT *client, GArray* servers, int phase) {
        char zeros[128];
        uint64_t size_host;
        uint32_t flags = NBD_FLAG_HAS_FLAGS;
@@ -1369,14 +1373,14 @@ CLIENT* negotiate(int net, CLIENT *client, GArray* servers) {
        uint64_t magic;
 
        memset(zeros, '\0', sizeof(zeros));
-       if(!client || !client->modern) {
+       if(phase & NEG_INIT) {
                /* common */
                if (write(net, INIT_PASSWD, 8) < 0) {
                        err_nonfatal("Negotiation failed: %m");
                        if(client)
                                exit(EXIT_FAILURE);
                }
-               if(!client || client->modern) {
+               if(phase & NEG_MODERN) {
                        /* modern */
                        magic = htonll(opts_magic);
                } else {
@@ -1389,7 +1393,7 @@ CLIENT* negotiate(int net, CLIENT *client, GArray* servers) {
                                exit(EXIT_FAILURE);
                }
        }
-       if(!client) {
+       if(phase & NEG_MODERN) {
                /* modern */
                uint32_t reserved;
                uint32_t opt;
@@ -1452,7 +1456,7 @@ CLIENT* negotiate(int net, CLIENT *client, GArray* servers) {
                flags |= NBD_FLAG_SEND_FUA;
        if (client->server->flags & F_ROTATIONAL)
                flags |= NBD_FLAG_ROTATIONAL;
-       if (!client->modern) {
+       if (phase & NEG_OLD) {
                /* oldstyle */
                flags = htonl(flags);
                if (write(client->net, &flags, 4) < 0)
@@ -1493,7 +1497,7 @@ int mainloop(CLIENT *client) {
 #ifdef DODBG
        int i = 0;
 #endif
-       negotiate(client->net, client, NULL);
+       negotiate(client->net, client, NULL, client->modern ? NEG_MODERN : (NEG_OLD | NEG_INIT));
        DEBUG("Entering request loop!\n");
        reply.magic = htonl(NBD_REPLY_MAGIC);
        reply.error = 0;
@@ -1932,7 +1936,7 @@ int serveloop(GArray* servers) {
                        if(FD_ISSET(modernsock, &rset)) {
                                if((net=accept(modernsock, (struct sockaddr *) &addrin, &addrinlen)) < 0)
                                        err("accept: %m");
-                               client = negotiate(net, NULL, servers);
+                               client = negotiate(net, NULL, servers, NEG_INIT | NEG_MODERN);
                                if(!client) {
                                        err_nonfatal("negotiation failed");
                                        close(net);