fix infinite loop in pipeTraffic

diff --git a/nsjail.cc b/nsjail.cc
index c988968bc9af49d8cb988f4af557d39a11418b4c..9c8c222f262f622b4eeeff1276960569a02bd8ff 100644 (file)
--- a/nsjail.cc
+++ b/nsjail.cc
@@ -139,6 +139,9 @@ static bool pipeTraffic(nsjconf_t* nsjconf, int listenfd) {
        });
        LOG_D("Waiting for fd activity");
        while (poll(fds.data(), fds.size(), -1) > 0) {
+               if (sigFatal > 0 || showProc) {
+                       return false;
+               }
                if (fds.back().revents != 0) {
                        LOG_D("New connection ready");
                        return true;
@@ -148,13 +151,19 @@ static bool pipeTraffic(nsjconf_t* nsjconf, int listenfd) {
                        bool read_ready = fds[i].events == 0 || (fds[i].revents & POLLIN) == POLLIN;
                        bool write_ready =
                            fds[i + 1].events == 0 || (fds[i + 1].revents & POLLOUT) == POLLOUT;
+                       bool pair_closed = (fds[i].revents & (POLLHUP | POLLERR)) != 0 ||
+                                          (fds[i + 1].revents & (POLLHUP | POLLERR)) != 0;
                        if (read_ready && write_ready) {
-                               if (splice(fds[i].fd, nullptr, fds[i + 1].fd, nullptr, 4096,
-                                       SPLICE_F_NONBLOCK) == -1 &&
-                                   errno != EAGAIN) {
+                               LOG_D("Read+write ready on %ld", i / 2);
+                               ssize_t rv = splice(fds[i].fd, nullptr, fds[i + 1].fd, nullptr,
+                                   4096, SPLICE_F_NONBLOCK);
+                               if (rv == -1 && errno != EAGAIN) {
                                        PLOG_E("splice fd pair #%ld {%d, %d}\n", i / 2, fds[i].fd,
                                            fds[i + 1].fd);
                                }
+                               if (rv == 0) {
+                                       pair_closed = true;
+                               }
                                fds[i].events = POLLIN;
                                fds[i + 1].events = POLLOUT;
                        } else if (read_ready) {
@@ -164,8 +173,7 @@ static bool pipeTraffic(nsjconf_t* nsjconf, int listenfd) {
                                LOG_D("Write ready on %ld", i / 2);
                                fds[i + 1].events = 0;
                        }
-                       if ((fds[i].revents & (POLLHUP | POLLERR)) != 0 ||
-                           (fds[i + 1].revents & (POLLHUP | POLLERR)) != 0) {
+                       if (pair_closed) {
                                LOG_D("Hangup on %ld", i / 2);
                                cleanup = true;
                                close(fds[i].fd);