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

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

1 files changed, 55 insertions, 11 deletions

diff --git a/networking/inetd.c b/networking/inetd.c
index 873fd9528..fc6847bb5 100644
--- 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: