diff --git a/prewarm-launcher.c b/prewarm-launcher.c
index 79d9d7e94..a3902dc85 100644
--- a/prewarm-launcher.c
+++ b/prewarm-launcher.c
@@ -47,6 +47,12 @@
 // }}}
 
 #define IO_BUZ_SZ 8192
+#define remove_i_from_array(array, i, count) { \
+    (count)--; \
+    if ((i) < (count)) { \
+        memmove((array) + (i), (array) + (i) + 1, sizeof((array)[0]) * ((count) - (i))); \
+    }}
+
 
 typedef struct transfer_buf {
     char *buf;
@@ -454,24 +460,31 @@ read_signals(void) {
     return true;
 }
 
+struct pollees {
+    struct pollfd poll_data[8];
+    struct {
+        int self_ttyfd, signal_read_fd, socket_fd, child_master_fd;
+    } idx;
+    size_t num_fds;
+};
+static struct pollees pollees = {0};
+
+#define register_for_poll(which) pollees.poll_data[pollees.num_fds].fd = which; pollees.poll_data[pollees.num_fds].events = POLLIN; pollees.idx.which = pollees.num_fds++;
+#define unregister_for_poll(which) if (pollees.idx.which > -1) { remove_i_from_array(pollees.poll_data, pollees.idx.which, pollees.num_fds); pollees.idx.which = -1; }
+#define set_poll_events(which, val) if (pollees.idx.which > -1) { pollees.poll_data[pollees.idx.which].events = (val); }
+#define poll_revents(which) ((pollees.idx.which > -1) ? pollees.poll_data[pollees.idx.which].revents : 0)
+
 static void
 loop(void) {
 #define fail(s) { print_error(s, errno); return; }
-#define pd(which) poll_data[which##_idx]
-#define check_fd(name) { if (pd(name).revents & POLLERR) { pe("File descriptor %s failed", #name); return; } if (pd(name).revents & POLLHUP) { pe("File descriptor %s hungup", #name); return; } }
-    struct pollfd poll_data[4];
-    enum { self_ttyfd_idx, signal_read_fd_idx, socket_fd_idx, child_master_fd_idx };
-#define init(name) pd(name).fd = name; pd(name).events = POLLIN;
-    init(self_ttyfd); init(socket_fd); init(signal_read_fd); init(child_master_fd);
-#undef init
+#define check_fd(name) { if (poll_revents(name) & POLLERR) { pe("File descriptor %s failed", #name); return; } if (poll_revents(name) & POLLHUP) { pe("File descriptor %s hungup", #name); return; } }
+    register_for_poll(self_ttyfd); register_for_poll(socket_fd); register_for_poll(signal_read_fd); register_for_poll(child_master_fd);
 
     while (true) {
         int ret;
-        pd(self_ttyfd).events = (to_child_tty.sz < IO_BUZ_SZ ? POLLIN : 0) | (from_child_tty.sz ? POLLOUT : 0);
-        if (socket_fd > -1) pd(socket_fd).events = POLLIN | (launch_msg.iov_len ? POLLOUT : 0);
-        else pd(socket_fd).events = 0;
-        if (child_master_fd > -1) pd(child_master_fd).events = (from_child_tty.sz < IO_BUZ_SZ ? POLLIN : 0) | (to_child_tty.sz ? POLLOUT : 0);
-        else pd(child_master_fd).events = 0;
+        set_poll_events(self_ttyfd, (to_child_tty.sz < IO_BUZ_SZ ? POLLIN : 0) | (from_child_tty.sz ? POLLOUT : 0));
+        set_poll_events(socket_fd, POLLIN | (launch_msg.iov_len ? POLLOUT : 0));
+        set_poll_events(child_master_fd, (from_child_tty.sz < IO_BUZ_SZ ? POLLIN : 0) | (to_child_tty.sz ? POLLOUT : 0));
 
         if (window_size_dirty && child_master_fd > -1 ) {
             if (!get_window_size()) fail("getting window size for self tty failed");
@@ -479,44 +492,43 @@ loop(void) {
             window_size_dirty = false;
         }
 
-        for (size_t i = 0; i < arraysz(poll_data); i++) poll_data[i].revents = 0;
-        while ((ret = poll(poll_data, arraysz(poll_data), -1)) == -1) { if (errno != EINTR) fail("poll() failed"); }
+        for (size_t i = 0; i < pollees.num_fds; i++) pollees.poll_data[i].revents = 0;
+        while ((ret = poll(pollees.poll_data, pollees.num_fds, -1)) == -1) { if (errno != EINTR) fail("poll() failed"); }
         if (!ret) continue;
 
-        if (pd(child_master_fd).revents & POLLIN) if (!read_or_transfer_from_child_tty()) fail("reading from child tty failed");
-        if (pd(self_ttyfd).revents & POLLOUT) if (!from_child_to_self()) fail("writing to self tty failed");
-        if (pd(self_ttyfd).revents & POLLIN) if (!read_or_transfer_from_self_tty()) fail("reading from self tty failed");
-        if (pd(child_master_fd).revents & POLLOUT) if (!from_self_to_child()) fail("writing to child tty failed");
-        if (pd(child_master_fd).revents & POLLHUP) {
+        if (poll_revents(child_master_fd) & POLLIN) if (!read_or_transfer_from_child_tty()) fail("reading from child tty failed");
+        if (poll_revents(self_ttyfd) & POLLOUT) if (!from_child_to_self()) fail("writing to self tty failed");
+        if (poll_revents(self_ttyfd) & POLLIN) if (!read_or_transfer_from_self_tty()) fail("reading from self tty failed");
+        if (poll_revents(child_master_fd) & POLLOUT) if (!from_self_to_child()) fail("writing to child tty failed");
+        if (poll_revents(child_master_fd) & POLLHUP) {
             // child has closed its tty, wait for exit code from prewarm zygote
             safe_close(child_master_fd); child_master_fd = -1;
+            unregister_for_poll(child_master_fd);
             if (!child_pid) return;
         }
 
-        check_fd(self_ttyfd);
-        if (child_master_fd > -1) check_fd(child_master_fd);
-        check_fd(signal_read_fd);
+        check_fd(self_ttyfd); check_fd(child_master_fd); check_fd(signal_read_fd);
 
         // signal_read_fd
-        if (pd(signal_read_fd).revents & POLLIN) if (!read_signals()) fail("reading from signal fd failed");
+        if (poll_revents(signal_read_fd) & POLLIN) if (!read_signals()) fail("reading from signal fd failed");
 
         // socket_fd
-        if (pd(socket_fd).revents & POLLERR) {
+        if (poll_revents(socket_fd) & POLLERR) {
             print_error("File descriptor socket_fd failed", 0); return;
         }
-        if (pd(socket_fd).revents & POLLIN) {
+        if (poll_revents(socket_fd) & POLLIN) {
             if (!read_child_data()) fail("reading information about child failed");
         }
-        if (pd(socket_fd).revents & POLLHUP) {
+        if (poll_revents(socket_fd) & POLLHUP) {
             if (from_child_buf[0]) { parse_int(from_child_buf, &exit_status); }
-            child_pid = 0;
+            child_pid = 0; safe_close(socket_fd); socket_fd = -1;
+            unregister_for_poll(socket_fd);
             if (child_master_fd < 0) return;
         }
-        if (pd(socket_fd).revents & POLLOUT) {
+        if (poll_revents(socket_fd) & POLLOUT) {
             if (!send_launch_msg()) fail("sending launch message failed");
         }
     }
-#undef pd
 #undef check_fd
 #undef fail
 }