BUG/MEDIUM: cli: _getsocks must send the peers sockets

This bug prevents to reload HAProxy when you have both the seamless
reload (-x / expose-fd listeners) and the peers.

Indeed the _getsocks command does not send the FDs of the peers
listeners, so if no reuseport is possible during the bind, the new
process will fail to bind and exits.

With this feature, it is not possible to fallback on the SIGTTOU method
if we didn't receive all the sockets, because you can't close() the
sockets of the new process without closing those of the previous
process, they are the same.

Should fix bug #443.

Must be backported as far as 1.8.

diff --git a/src/cli.c b/src/cli.c
index e1c8bdcbc12a4e148c51dfd9ef05262b9e6446cc..8fcbccd1fea1fca44d981f584730e6ceae8e48be 100644 (file)
--- a/src/cli.c
+++ b/src/cli.c
@@ -1610,6 +1610,7 @@ static int _getsocks(char **args, char *payload, struct appctx *appctx, void *pr
        int *tmpfd;
        int tot_fd_nb = 0;
        struct proxy *px;
+       struct peers *prs;
        int i = 0;
        int fd = -1;
        int curoff = 0;
@@ -1662,6 +1663,22 @@ static int _getsocks(char **args, char *payload, struct appctx *appctx, void *pr
                }
                px = px->next;
        }
+       prs = cfg_peers;
+       while (prs) {
+               if (prs->peers_fe) {
+                       struct listener *l;
+
+                       list_for_each_entry(l, &prs->peers_fe->conf.listeners, by_fe) {
+                               /* Only transfer IPv4/IPv6/UNIX sockets */
+                               if (l->state >= LI_ZOMBIE &&
+                                   (l->proto->sock_family == AF_INET ||
+                                    l->proto->sock_family == AF_INET6 ||
+                                    l->proto->sock_family == AF_UNIX))
+                                       tot_fd_nb++;
+                       }
+               }
+               prs = prs->next;
+       }
        if (tot_fd_nb == 0)
                goto out;
 
@@ -1685,7 +1702,6 @@ static int _getsocks(char **args, char *payload, struct appctx *appctx, void *pr
        cmsg->cmsg_type = SCM_RIGHTS;
        tmpfd = (int *)CMSG_DATA(cmsg);
 
-       px = proxies_list;
        /* For each socket, e message is sent, containing the following :
         *  Size of the namespace name (or 0 if none), as an unsigned char.
         *  The namespace name, if any
@@ -1702,6 +1718,7 @@ static int _getsocks(char **args, char *payload, struct appctx *appctx, void *pr
                goto out;
        }
        iov.iov_base = tmpbuf;
+       px = proxies_list;
        while (px) {
                struct listener *l;
 
@@ -1735,7 +1752,6 @@ static int _getsocks(char **args, char *payload, struct appctx *appctx, void *pr
                                    sizeof(l->options));
                                curoff += sizeof(l->options);
 
-
                                i++;
                        } else
                                continue;
@@ -1756,10 +1772,70 @@ static int _getsocks(char **args, char *payload, struct appctx *appctx, void *pr
                                }
                                curoff = 0;
                        }
-
                }
                px = px->next;
        }
+       /* should be done for peers too */
+       prs = cfg_peers;
+       while (prs) {
+               if (prs->peers_fe) {
+                       struct listener *l;
+
+                       list_for_each_entry(l, &prs->peers_fe->conf.listeners, by_fe) {
+                               int ret;
+                               /* Only transfer IPv4/IPv6 sockets */
+                               if (l->state >= LI_ZOMBIE &&
+                                   (l->proto->sock_family == AF_INET ||
+                                    l->proto->sock_family == AF_INET6 ||
+                                    l->proto->sock_family == AF_UNIX)) {
+                                       memcpy(&tmpfd[i % MAX_SEND_FD], &l->fd, sizeof(l->fd));
+                                       if (!l->netns)
+                                               tmpbuf[curoff++] = 0;
+#ifdef USE_NS
+                                       else {
+                                               char *name = l->netns->node.key;
+                                               unsigned char len = l->netns->name_len;
+                                               tmpbuf[curoff++] = len;
+                                               memcpy(tmpbuf + curoff, name, len);
+                                               curoff += len;
+                                       }
+#endif
+                                       if (l->interface) {
+                                               unsigned char len = strlen(l->interface);
+                                               tmpbuf[curoff++] = len;
+                                               memcpy(tmpbuf + curoff, l->interface, len);
+                                               curoff += len;
+                                       } else
+                                               tmpbuf[curoff++] = 0;
+                                       memcpy(tmpbuf + curoff, &l->options,
+                                              sizeof(l->options));
+                                       curoff += sizeof(l->options);
+
+                                       i++;
+                               } else
+                                       continue;
+                               if ((!(i % MAX_SEND_FD))) {
+                                       iov.iov_len = curoff;
+                                       if (sendmsg(fd, &msghdr, 0) != curoff) {
+                                               ha_warning("Failed to transfer sockets\n");
+                                               goto out;
+                                       }
+                                       /* Wait for an ack */
+                                       do {
+                                               ret = recv(fd, &tot_fd_nb,
+                                                          sizeof(tot_fd_nb), 0);
+                                       } while (ret == -1 && errno == EINTR);
+                                       if (ret <= 0) {
+                                               ha_warning("Unexpected error while transferring sockets\n");
+                                               goto out;
+                                       }
+                                       curoff = 0;
+                               }
+                       }
+               }
+               prs = prs->next;
+       }
+
        if (i % MAX_SEND_FD) {
                iov.iov_len = curoff;
                cmsg->cmsg_len = CMSG_LEN((i % MAX_SEND_FD) * sizeof(int));