inetd: fix a case when we have zero services

1 files changed, 13 insertions, 6 deletions

diff --git a/networking/inetd.c b/networking/inetd.c
index f80b51052..bf018d774 100644
--- a/networking/inetd.c
+++ b/networking/inetd.c
@@ -223,7 +223,7 @@ typedef struct servtab_t {
         smallint se_checked;                  /* looked at during merge */
         unsigned se_max;                      /* allowed instances per minute */
         unsigned se_count;                    /* number started since se_time */
-        unsigned se_time;                     /* whem we started counting */
+        unsigned se_time;                     /* when we started counting */
         char *se_user;                        /* user name to run as */
         char *se_group;                       /* group name to run as, can be NULL */
 #ifdef INETD_BUILTINS_ENABLED
@@ -295,8 +295,10 @@ struct globals {
         struct rlimit rlim_ofile;
         servtab_t *serv_list;
         int global_queuelen;
+        int maxsock;            /* max fd# in allsock, -1: unknown */
+        /* whenever maxsock grows, prev_maxsock is set to new maxsock,
+         * but if maxsock is set to -1, prev_maxsock is not changed */
         int prev_maxsock;
-        int maxsock;
         unsigned max_concurrency;
         smallint alarm_armed;
         uid_t real_uid; /* user ID who ran us */
@@ -321,8 +323,8 @@ struct BUG_G_too_big {
 #define rlim_ofile      (G.rlim_ofile     )
 #define serv_list       (G.serv_list      )
 #define global_queuelen (G.global_queuelen)
-#define prev_maxsock    (G.prev_maxsock   )
 #define maxsock         (G.maxsock        )
+#define prev_maxsock    (G.prev_maxsock   )
 #define max_concurrency (G.max_concurrency)
 #define alarm_armed     (G.alarm_armed    )
 #define real_uid        (G.real_uid       )
@@ -459,7 +461,7 @@ static void add_fd_to_set(int fd)
                 FD_SET(fd, &allsock);
                 if (maxsock >= 0 && fd > maxsock) {
                         prev_maxsock = maxsock = fd;
-                        if ((rlim_t)maxsock > rlim_ofile_cur - FD_MARGIN)
+                        if ((rlim_t)fd > rlim_ofile_cur - FD_MARGIN)
                                 bump_nofile();
                 }
         }
@@ -468,6 +470,10 @@ static void add_fd_to_set(int fd)
 static void recalculate_maxsock(void)
 {
         int fd = 0;
+
+        /* We may have no services, in this case maxsock should still be >= 0
+         * (code elsewhere is not happy with maxsock == -1) */
+        maxsock = 0;
         while (fd <= prev_maxsock) {
                 if (FD_ISSET(fd, &allsock))
                         maxsock = fd;
@@ -1161,7 +1167,8 @@ int inetd_main(int argc UNUSED_PARAM, char **argv)
 
                 readable = allsock; /* struct copy */
                 /* if there are no fds to wait on, we will block
-                 * until signal wakes us up */
+                 * until signal wakes us up (maxsock == 0, but readable
+                 * never contains fds 0 and 1...) */
                 ready_fd_cnt = select(maxsock + 1, &readable, NULL, NULL, NULL);
                 if (ready_fd_cnt < 0) {
                         if (errno != EINTR) {
@@ -1418,7 +1425,7 @@ static void echo_dg(int s, servtab_t *sep)
 
 
 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
-/* Discard service -- ignore data. MMU arches only. */
+/* Discard service -- ignore data. */
 /* ARGSUSED */
 static void discard_stream(int s, servtab_t *sep UNUSED_PARAM)
 {