timeout robustness: Introduce adns__timeout_{set,clear}

[adns.git] / src / event.c

diff --git a/src/event.c b/src/event.c
index b36288ddfab610e305a4205d659f963bdaabb4d4..845bc690af88a80a3308d2ef3f5c89cb1baa3902 100644 (file)
--- a/src/event.c
+++ b/src/event.c
@@ -6,7 +6,7 @@
  */
 /*
  *  This file is part of adns, which is
- *    Copyright (C) 1997-2000,2003,2006,2014-2016  Ian Jackson
+ *    Copyright (C) 1997-2000,2003,2006,2014-2016,2020  Ian Jackson
  *    Copyright (C) 2014  Mark Wooding
  *    Copyright (C) 1999-2000,2003,2006  Tony Finch
  *    Copyright (C) 1991 Massachusetts Institute of Technology
@@ -149,6 +149,11 @@ void adns__tcp_tryconnect(adns_state ads, struct timeval now) {
 
 /* Timeout handling functions. */
 
+void adns__timeout_set(adns_query qu, struct timeval now, int ms) {
+  qu->timeout_expires= now;
+  timevaladd(&qu->timeout_expires,ms);
+}
+
 void adns__must_gettimeofday(adns_state ads, const struct timeval **now_io,
                             struct timeval *tv_buf) {
   const struct timeval *now;
@@ -212,8 +217,8 @@ static void timeouts_queue(adns_state ads, int act,
   
   for (qu= queue->head; qu; qu= nqu) {
     nqu= qu->next;
-    if (!timercmp(&now,&qu->timeout,>)) {
-      inter_maxtoabs(tv_io,tvbuf,now,qu->timeout);
+    if (!timercmp(&now,&qu->timeout_expires,>)) {
+      inter_maxtoabs(tv_io,tvbuf,now,qu->timeout_expires);
     } else {
       if (!act) { inter_immed(tv_io,tvbuf); return; }
       LIST_UNLINK(*queue,qu);
@@ -284,7 +289,7 @@ void adns__timeouts(adns_state ads, int act,
 void adns_firsttimeout(adns_state ads,
                       struct timeval **tv_io, struct timeval *tvbuf,
                       struct timeval now) {
-  adns__consistency(ads,0,cc_entex);
+  adns__consistency(ads,0,cc_enter);
   adns__timeouts(ads, 0, tv_io,tvbuf, now);
   adns__returning(ads,0);
 }
@@ -292,7 +297,7 @@ void adns_firsttimeout(adns_state ads,
 void adns_processtimeouts(adns_state ads, const struct timeval *now) {
   struct timeval tv_buf;
 
-  adns__consistency(ads,0,cc_entex);
+  adns__consistency(ads,0,cc_enter);
   adns__must_gettimeofday(ads,&now,&tv_buf);
   if (now) adns__timeouts(ads, 1, 0,0, *now);
   adns__returning(ads,0);
@@ -346,7 +351,7 @@ int adns_processreadable(adns_state ads, int fd, const struct timeval *now) {
   struct udpsocket *udp;
   adns_sockaddr udpaddr;
   
-  adns__consistency(ads,0,cc_entex);
+  adns__consistency(ads,0,cc_enter);
 
   switch (ads->tcpstate) {
   case server_disconnected:
@@ -433,7 +438,7 @@ xit:
 int adns_processwriteable(adns_state ads, int fd, const struct timeval *now) {
   int r;
   
-  adns__consistency(ads,0,cc_entex);
+  adns__consistency(ads,0,cc_enter);
 
   switch (ads->tcpstate) {
   case server_disconnected:
@@ -488,6 +493,7 @@ int adns_processwriteable(adns_state ads, int fd, const struct timeval *now) {
        adns__tcp_broken(ads,"write",strerror(errno));
        r= 0; goto xit;
       } else if (r>0) {
+       assert(r <= ads->tcpsend.used);
        ads->tcpsend.used -= r;
        memmove(ads->tcpsend.buf,ads->tcpsend.buf+r,ads->tcpsend.used);
       }
@@ -505,7 +511,7 @@ xit:
   
 int adns_processexceptional(adns_state ads, int fd,
                            const struct timeval *now) {
-  adns__consistency(ads,0,cc_entex);
+  adns__consistency(ads,0,cc_enter);
   switch (ads->tcpstate) {
   case server_disconnected:
   case server_broken:
@@ -574,7 +580,7 @@ void adns_beforeselect(adns_state ads, int *maxfd_io, fd_set *readfds_io,
   struct pollfd pollfds[MAX_POLLFDS];
   int i, fd, maxfd, npollfds;
   
-  adns__consistency(ads,0,cc_entex);
+  adns__consistency(ads,0,cc_enter);
 
   if (tv_mod && (!*tv_mod || (*tv_mod)->tv_sec || (*tv_mod)->tv_usec)) {
     /* The caller is planning to sleep. */
@@ -605,7 +611,7 @@ void adns_afterselect(adns_state ads, int maxfd, const fd_set *readfds,
   struct pollfd pollfds[MAX_POLLFDS];
   int npollfds, i;
 
-  adns__consistency(ads,0,cc_entex);
+  adns__consistency(ads,0,cc_enter);
   adns__must_gettimeofday(ads,&now,&tv_buf);
   if (!now) goto xit;
   adns_processtimeouts(ads,now);
@@ -623,10 +629,24 @@ xit:
 /* General helpful functions. */
 
 void adns_globalsystemfailure(adns_state ads) {
-  adns__consistency(ads,0,cc_entex);
+  /* Must not be called by adns during actual processing of a
+   * particular query, since it reenters adns.  Only safe to call in
+   * situations where it would be safe to call adns_returning. */
+  adns__consistency(ads,0,cc_enter);
 
-  while (ads->udpw.head) adns__query_fail(ads->udpw.head, adns_s_systemfail);
-  while (ads->tcpw.head) adns__query_fail(ads->tcpw.head, adns_s_systemfail);
+  for (;;) {
+    adns_query qu;
+#define GSF_QQ(QQ)                             \
+    if ((qu= ads->QQ.head)) {                  \
+      LIST_UNLINK(ads->QQ,qu);                 \
+      adns__query_fail(qu, adns_s_systemfail); \
+      continue;                                        \
+    }
+    GSF_QQ(udpw);
+    GSF_QQ(tcpw);
+#undef GSF_QQ
+    break;
+  }
   
   switch (ads->tcpstate) {
   case server_connecting:
@@ -648,7 +668,7 @@ int adns_processany(adns_state ads) {
   struct pollfd pollfds[MAX_POLLFDS];
   int npollfds;
 
-  adns__consistency(ads,0,cc_entex);
+  adns__consistency(ads,0,cc_enter);
 
   r= gettimeofday(&now,0);
   if (!r) adns_processtimeouts(ads,&now);
@@ -707,7 +727,7 @@ int adns_wait(adns_state ads,
   fd_set readfds, writefds, exceptfds;
   struct timeval tvbuf, *tvp;
   
-  adns__consistency(ads,*query_io,cc_entex);
+  adns__consistency(ads,*query_io,cc_enter);
   for (;;) {
     r= adns__internal_check(ads,query_io,answer_r,context_r);
     if (r != EAGAIN) break;
@@ -739,7 +759,7 @@ int adns_check(adns_state ads,
   struct timeval now;
   int r;
   
-  adns__consistency(ads,*query_io,cc_entex);
+  adns__consistency(ads,*query_io,cc_enter);
   r= gettimeofday(&now,0);
   if (!r) adns__autosys(ads,now);