inetd: close new udp fd in "udp nowait" case

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/networking/inetd.c b/networking/inetd.c
index 873fd95281fdd668514588c9c955a4edf99877da..fc6847bb5dc3613690027df543cbd33c780a8e12 100644 (file)
--- a/networking/inetd.c
+++ b/networking/inetd.c
@@ -357,10 +357,26 @@ struct BUG_G_too_big {
        config_filename = "/etc/inetd.conf"; \
 } while (0)
 
+#if 1
+# define dbg(...) ((void)0)
+#else
+# define dbg(...) \
+do { \
+       int dbg_fd = open("inetd_debug.log", O_WRONLY | O_CREAT | O_APPEND, 0666); \
+       if (dbg_fd >= 0) { \
+               fdprintf(dbg_fd, "%d: ", getpid()); \
+               fdprintf(dbg_fd, __VA_ARGS__); \
+               close(dbg_fd); \
+       } \
+} while (0)
+#endif
+
 static void maybe_close(int fd)
 {
-       if (fd >= 0)
+       if (fd >= 0) {
                close(fd);
+               dbg("closed fd:%d\n", fd);
+       }
 }
 
 // TODO: move to libbb?
@@ -464,7 +480,9 @@ static void remove_fd_from_set(int fd)
 {
        if (fd >= 0) {
                FD_CLR(fd, &allsock);
+               dbg("stopped listening on fd:%d\n", fd);
                maxsock = -1;
+               dbg("maxsock:%d\n", maxsock);
        }
 }
 
@@ -472,8 +490,10 @@ static void add_fd_to_set(int fd)
 {
        if (fd >= 0) {
                FD_SET(fd, &allsock);
+               dbg("started listening on fd:%d\n", fd);
                if (maxsock >= 0 && fd > maxsock) {
                        prev_maxsock = maxsock = fd;
+                       dbg("maxsock:%d\n", maxsock);
                        if ((rlim_t)fd > rlim_ofile_cur - FD_MARGIN)
                                bump_nofile();
                }
@@ -492,6 +512,7 @@ static void recalculate_maxsock(void)
                        maxsock = fd;
                fd++;
        }
+       dbg("recalculated maxsock:%d\n", maxsock);
        prev_maxsock = maxsock;
        if ((rlim_t)maxsock > rlim_ofile_cur - FD_MARGIN)
                bump_nofile();
@@ -549,8 +570,13 @@ static void prepare_socket_fd(servtab_t *sep)
                rearm_alarm();
                return;
        }
-       if (sep->se_socktype == SOCK_STREAM)
+
+       if (sep->se_socktype == SOCK_STREAM) {
                listen(fd, global_queuelen);
+               dbg("new sep->se_fd:%d (stream)\n", fd);
+       } else {
+               dbg("new sep->se_fd:%d (!stream)\n", fd);
+       }
 
        add_fd_to_set(fd);
        sep->se_fd = fd;
@@ -1012,7 +1038,7 @@ static void reread_config_file(int sig UNUSED_PARAM)
         * new config file doesnt have them. */
        block_CHLD_HUP_ALRM(&omask);
        sepp = &serv_list;
-       while ((sep = *sepp)) {
+       while ((sep = *sepp) != NULL) {
                if (sep->se_checked) {
                        sepp = &sep->se_next;
                        continue;
@@ -1206,11 +1232,13 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
                        }
                        continue;
                }
+               dbg("ready_fd_cnt:%d\n", ready_fd_cnt);
 
                for (sep = serv_list; ready_fd_cnt && sep; sep = sep->se_next) {
                        if (sep->se_fd == -1 || !FD_ISSET(sep->se_fd, &readable))
                                continue;
 
+                       dbg("ready fd:%d\n", sep->se_fd);
                        ready_fd_cnt--;
                        ctrl = sep->se_fd;
                        accepted_fd = -1;
@@ -1218,6 +1246,7 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
                        if (!sep->se_wait) {
                                if (sep->se_socktype == SOCK_STREAM) {
                                        ctrl = accepted_fd = accept(sep->se_fd, NULL, NULL);
+                                       dbg("accepted_fd:%d\n", accepted_fd);
                                        if (ctrl < 0) {
                                                if (errno != EINTR)
                                                        bb_perror_msg("accept (for %s)", sep->se_service);
@@ -1238,19 +1267,22 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
  * (can create many copies of same child, etc).
  * Parent must create and use new socket instead. */
                                        new_udp_fd = socket(sep->se_family, SOCK_DGRAM, 0);
+                                       dbg("new_udp_fd:%d\n", new_udp_fd);
                                        if (new_udp_fd < 0) { /* error: eat packet, forget about it */
  udp_err:
                                                recv(sep->se_fd, line, LINE_SIZE, MSG_DONTWAIT);
                                                continue;
                                        }
                                        setsockopt_reuseaddr(new_udp_fd);
-                                       /* TODO: better do bind after vfork in parent,
+                                       /* TODO: better do bind after fork in parent,
                                         * so that we don't have two wildcard bound sockets
                                         * even for a brief moment? */
                                        if (bind(new_udp_fd, &sep->se_lsa->u.sa, sep->se_lsa->len) < 0) {
+                                               dbg("bind(new_udp_fd) failed\n");
                                                close(new_udp_fd);
                                                goto udp_err;
                                        }
+                                       dbg("bind(new_udp_fd) succeeded\n");
                                }
                        }
 
@@ -1278,6 +1310,7 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
                                                        sep->se_count = 0;
                                                        rearm_alarm(); /* will revive it in RETRYTIME sec */
                                                        restore_sigmask(&omask);
+                                                       maybe_close(new_udp_fd);
                                                        maybe_close(accepted_fd);
                                                        continue; /* -> check next fd in fd set */
                                                }
@@ -1298,17 +1331,18 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
                                        bb_perror_msg("vfork"+1);
                                        sleep(1);
                                        restore_sigmask(&omask);
+                                       maybe_close(new_udp_fd);
                                        maybe_close(accepted_fd);
                                        continue; /* -> check next fd in fd set */
                                }
                                if (pid == 0)
                                        pid--; /* -1: "we did fork and we are child" */
                        }
-                       /* if pid == 0 here, we never forked */
+                       /* if pid == 0 here, we didn't fork */
 
                        if (pid > 0) { /* parent */
                                if (sep->se_wait) {
-                                       /* tcp wait: we passed listening socket to child,
+                                       /* wait: we passed socket to child,
                                         * will wait for child to terminate */
                                        sep->se_wait = pid;
                                        remove_fd_from_set(sep->se_fd);
@@ -1317,17 +1351,19 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
                                        /* udp nowait: child connected the socket,
                                         * we created and will use new, unconnected one */
                                        xmove_fd(new_udp_fd, sep->se_fd);
+                                       dbg("moved new_udp_fd:%d to sep->se_fd:%d\n", new_udp_fd, sep->se_fd);
                                }
                                restore_sigmask(&omask);
                                maybe_close(accepted_fd);
                                continue; /* -> check next fd in fd set */
                        }
 
-                       /* we are either child or didn't vfork at all */
+                       /* we are either child or didn't fork at all */
 #ifdef INETD_BUILTINS_ENABLED
                        if (sep->se_builtin) {
-                               if (pid) { /* "pid" is -1: we did vfork */
+                               if (pid) { /* "pid" is -1: we did fork */
                                        close(sep->se_fd); /* listening socket */
+                                       dbg("closed sep->se_fd:%d\n", sep->se_fd);
                                        logmode = LOGMODE_NONE; /* make xwrite etc silent */
                                }
                                restore_sigmask(&omask);
@@ -1335,7 +1371,7 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
                                        sep->se_builtin->bi_stream_fn(ctrl, sep);
                                else
                                        sep->se_builtin->bi_dgram_fn(ctrl, sep);
-                               if (pid) /* we did vfork */
+                               if (pid) /* we did fork */
                                        _exit(EXIT_FAILURE);
                                maybe_close(accepted_fd);
                                continue; /* -> check next fd in fd set */
@@ -1345,9 +1381,14 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
                        setsid();
                        /* "nowait" udp */
                        if (new_udp_fd >= 0) {
-                               len_and_sockaddr *lsa = xzalloc_lsa(sep->se_family);
+                               len_and_sockaddr *lsa;
+                               int r;
+
+                               close(new_udp_fd);
+                               dbg("closed new_udp_fd:%d\n", new_udp_fd);
+                               lsa = xzalloc_lsa(sep->se_family);
                                /* peek at the packet and remember peer addr */
-                               int r = recvfrom(ctrl, NULL, 0, MSG_PEEK|MSG_DONTWAIT,
+                               r = recvfrom(ctrl, NULL, 0, MSG_PEEK|MSG_DONTWAIT,
                                        &lsa->u.sa, &lsa->len);
                                if (r < 0)
                                        goto do_exit1;
@@ -1355,6 +1396,7 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
                                 * only packets from this peer will be recv'ed,
                                 * and bare write()/send() will work on it */
                                connect(ctrl, &lsa->u.sa, lsa->len);
+                               dbg("connected ctrl:%d to remote peer\n", ctrl);
                                free(lsa);
                        }
                        /* prepare env and exec program */
@@ -1391,6 +1433,7 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
                         */
                        xmove_fd(ctrl, STDIN_FILENO);
                        xdup2(STDIN_FILENO, STDOUT_FILENO);
+                       dbg("moved ctrl:%d to fd 0,1[,2]\n", ctrl);
                        /* manpages of inetd I managed to find either say
                         * that stderr is also redirected to the network,
                         * or do not talk about redirection at all (!) */
@@ -1403,6 +1446,7 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
                                        maybe_close(sep2->se_fd);
                        sigaction_set(SIGPIPE, &saved_pipe_handler);
                        restore_sigmask(&omask);
+                       dbg("execing:'%s'\n", sep->se_program);
                        BB_EXECVP(sep->se_program, sep->se_argv);
                        bb_perror_msg("can't execute '%s'", sep->se_program);
  do_exit1: