Fix boilerplate code for re-running system calls on EINTR and EAGAIN etc.

The nasty code with static variable in retry_send() which
avoids looping forever needs to be called on success of the syscall,
to reset the static variable.

src/bpf.c

@@ -359,7 +359,7 @@ void send_via_bpf(struct dhcp_packet *mess, size_t len,
   iov[3].iov_base = mess;
   iov[3].iov_len = len;
 
-  while (writev(daemon->dhcp_raw_fd, iov, 4) == -1 && retry_send());
+  while (retry_send(writev(daemon->dhcp_raw_fd, iov, 4)));
 }
 
 #endif /* defined(HAVE_BSD_NETWORK) && defined(HAVE_DHCP) */

src/dhcp.c

@@ -443,7 +443,7 @@ void dhcp_packet(time_t now, int pxe_fd)
   setsockopt(fd, IPPROTO_IP, IP_BOUND_IF, &iface_index, sizeof(iface_index));
 #endif
   
-  while(sendmsg(fd, &msg, 0) == -1 && retry_send());
+  while(retry_send(sendmsg(fd, &msg, 0)));
 }
  
 /* check against secondary interface addresses */

src/dhcp6.c

@@ -225,9 +225,9 @@ void dhcp6_packet(time_t now)
   if (port != 0)
     {
       from.sin6_port = htons(port);
-      while (sendto(daemon->dhcp6fd, daemon->outpacket.iov_base, save_counter(0), 
-		    0, (struct sockaddr *)&from, sizeof(from)) == -1 &&
-	   retry_send());
+      while (retry_send(sendto(daemon->dhcp6fd, daemon->outpacket.iov_base, 
+			       save_counter(0), 0, (struct sockaddr *)&from, 
+			       sizeof(from))));
     }
 }
 

src/dnsmasq.c

@@ -444,7 +444,7 @@ int main (int argc, char **argv)
 	      char *msg;
 
 	      /* close our copy of write-end */
-	      close(err_pipe[1]);
+	      while (retry_send(close(err_pipe[1])));
 	      
 	      /* check for errors after the fork */
 	      if (read_event(err_pipe[0], &ev, &msg))
@@ -453,7 +453,7 @@ int main (int argc, char **argv)
 	      _exit(EC_GOOD);
 	    } 
 	  
-	  close(err_pipe[0]);
+	  while (retry_send(close(err_pipe[0])));
 
 	  /* NO calls to die() from here on. */
 	  
@@ -505,10 +505,12 @@ int main (int argc, char **argv)
 	    {
 	      if (!read_write(fd, (unsigned char *)daemon->namebuff, strlen(daemon->namebuff), 0))
 		err = 1;
-	      
-	      while (!err && close(fd) == -1)
-		if (!retry_send())
-		  err = 1;
+	      else 
+		{
+		  while (retry_send(close(fd)));
+		  if (errno != 0)
+		    err = 1;
+		}
 	    }
 
 	  if (err)
@@ -813,7 +815,7 @@ int main (int argc, char **argv)
 
   /* finished start-up - release original process */
   if (err_pipe[1] != -1)
-    close(err_pipe[1]);
+    while (retry_send(close(err_pipe[1])));
   
   if (daemon->port != 0)
     check_servers();
@@ -1319,7 +1321,7 @@ static void async_event(int pipe, time_t now)
 	    do {
 	      helper_write();
 	    } while (!helper_buf_empty() || do_script_run(now));
-	    close(daemon->helperfd);
+	    while (retry_send(close(daemon->helperfd)));
 	  }
 #endif
 	
@@ -1544,7 +1546,7 @@ static void check_dns_listeners(fd_set *set, time_t now)
 	  
 	  if (getsockname(confd, (struct sockaddr *)&tcp_addr, &tcp_len) == -1)
 	    {
-	      close(confd);
+	      while (retry_send(close(confd)));
 	      continue;
 	    }
 	  
@@ -1609,7 +1611,7 @@ static void check_dns_listeners(fd_set *set, time_t now)
 	  if (!client_ok)
 	    {
 	      shutdown(confd, SHUT_RDWR);
-	      close(confd);
+	      while (retry_send(close(confd)));
 	    }
 #ifndef NO_FORK
 	  else if (!option_bool(OPT_DEBUG) && (p = fork()) != 0)
@@ -1624,7 +1626,7 @@ static void check_dns_listeners(fd_set *set, time_t now)
 			break;
 		      }
 		}
-	      close(confd);
+	      while (retry_send(close(confd)));
 
 	      /* The child can use up to TCP_MAX_QUERIES ids, so skip that many. */
 	      daemon->log_id += TCP_MAX_QUERIES;
@@ -1669,7 +1671,7 @@ static void check_dns_listeners(fd_set *set, time_t now)
 	      buff = tcp_request(confd, now, &tcp_addr, netmask, auth_dns);
 	       
 	      shutdown(confd, SHUT_RDWR);
-	      close(confd);
+	      while (retry_send(close(confd)));
 	      
 	      if (buff)
 		free(buff);
@@ -1678,7 +1680,7 @@ static void check_dns_listeners(fd_set *set, time_t now)
 		if (s->tcpfd != -1)
 		  {
 		    shutdown(s->tcpfd, SHUT_RDWR);
-		    close(s->tcpfd);
+		    while (retry_send(close(s->tcpfd)));
 		  }
 #ifndef NO_FORK		   
 	      if (!option_bool(OPT_DEBUG))
@@ -1756,9 +1758,8 @@ int icmp_ping(struct in_addr addr)
     j = (j & 0xffff) + (j >> 16);  
   packet.icmp.icmp_cksum = (j == 0xffff) ? j : ~j;
   
-  while (sendto(fd, (char *)&packet.icmp, sizeof(struct icmp), 0, 
-		(struct sockaddr *)&saddr, sizeof(saddr)) == -1 &&
-	 retry_send());
+  while (retry_send(sendto(fd, (char *)&packet.icmp, sizeof(struct icmp), 0, 
+			   (struct sockaddr *)&saddr, sizeof(saddr))));
   
   for (now = start = dnsmasq_time(); 
        difftime(now, start) < (float)PING_WAIT;)
@@ -1820,7 +1821,7 @@ int icmp_ping(struct in_addr addr)
     }
   
 #if defined(HAVE_LINUX_NETWORK) || defined(HAVE_SOLARIS_NETWORK)
-  close(fd);
+  while (retry_send(close(fd)));
 #else
   opt = 1;
   setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &opt, sizeof(opt));

src/dnsmasq.h

@@ -1177,7 +1177,7 @@ int is_same_net6(struct in6_addr *a, struct in6_addr *b, int prefixlen);
 u64 addr6part(struct in6_addr *addr);
 void setaddr6part(struct in6_addr *addr, u64 host);
 #endif
-int retry_send(void);
+int retry_send(ssize_t rc);
 void prettyprint_time(char *buf, unsigned int t);
 int prettyprint_addr(union mysockaddr *addr, char *buf);
 int parse_hex(char *in, unsigned char *out, int maxlen, 

src/forward.c

@@ -103,15 +103,11 @@ int send_from(int fd, int nowild, char *packet, size_t len,
 #endif
     }
   
-  while (sendmsg(fd, &msg, 0) == -1)
+  while (retry_send(sendmsg(fd, &msg, 0)));
+
+  /* If interface is still in DAD, EINVAL results - ignore that. */
+  if (errno != 0 && errno != EINVAL)
     {
-      if (retry_send())
-	continue;
-      
-      /* If interface is still in DAD, EINVAL results - ignore that. */
-      if (errno == EINVAL)
-	break;
-      
       my_syslog(LOG_ERR, _("failed to send packet: %s"), strerror(errno));
       return 0;
     }
@@ -297,9 +293,9 @@ static int forward_query(int udpfd, union mysockaddr *udpaddr,
 		fd = forward->rfd4->fd;
 	    }
 	  
-	  while (sendto(fd, (char *)header, plen, 0,
-			&forward->sentto->addr.sa,
-			sa_len(&forward->sentto->addr)) == -1 && retry_send());
+	  while (retry_send( sendto(fd, (char *)header, plen, 0,
+				    &forward->sentto->addr.sa,
+				    sa_len(&forward->sentto->addr))));
 	  
 	  return 1;
 	}
@@ -469,14 +465,12 @@ static int forward_query(int udpfd, union mysockaddr *udpaddr,
 #endif
 		}
 	      
-	      if (sendto(fd, (char *)header, plen, 0,
-			 &start->addr.sa,
-			 sa_len(&start->addr)) == -1)
-		{
-		  if (retry_send())
-		    continue;
-		}
-	      else
+	      if (retry_send(sendto(fd, (char *)header, plen, 0,
+				    &start->addr.sa,
+				    sa_len(&start->addr))))
+		continue;
+	    
+	      if (errno == 0)
 		{
 		  /* Keep info in case we want to re-send this packet */
 		  daemon->srv_save = start;
@@ -932,7 +926,9 @@ void reply_query(int fd, int family, time_t now)
 		  
 		  if (fd != -1)
 		    {
-		      while (sendto(fd, (char *)header, nn, 0, &server->addr.sa, sa_len(&server->addr)) == -1 && retry_send()); 
+		      while (retry_send(sendto(fd, (char *)header, nn, 0, 
+					       &server->addr.sa, 
+					       sa_len(&server->addr)))); 
 		      server->queries++;
 		    }
 		  
@@ -2228,8 +2224,9 @@ void resend_query()
       else
 	return;
       
-      while(sendto(fd, daemon->packet, daemon->packet_len, 0,
-		   &daemon->srv_save->addr.sa, sa_len(&daemon->srv_save->addr)) == -1 && retry_send()); 
+      while(retry_send(sendto(fd, daemon->packet, daemon->packet_len, 0,
+			      &daemon->srv_save->addr.sa, 
+			      sa_len(&daemon->srv_save->addr)))); 
     }
 }
 

src/ipset.c

@@ -121,7 +121,6 @@ static int new_add_to_ipset(const char *setname, const struct all_addr *ipaddr,
   struct my_nlattr *nested[2];
   uint8_t proto;
   int addrsz = INADDRSZ;
-  ssize_t rc;
 
 #ifdef HAVE_IPV6
   if (af == AF_INET6)
@@ -162,9 +161,10 @@ static int new_add_to_ipset(const char *setname, const struct all_addr *ipaddr,
   nested[1]->nla_len = (void *)buffer + NL_ALIGN(nlh->nlmsg_len) - (void *)nested[1];
   nested[0]->nla_len = (void *)buffer + NL_ALIGN(nlh->nlmsg_len) - (void *)nested[0];
 	
-  while ((rc = sendto(ipset_sock, buffer, nlh->nlmsg_len, 0,
-		      (struct sockaddr *)&snl, sizeof(snl))) == -1 && retry_send());
-  return rc;
+  while (retry_send(sendto(ipset_sock, buffer, nlh->nlmsg_len, 0,
+			   (struct sockaddr *)&snl, sizeof(snl))));
+								    
+  return errno == 0 ? 0 : -1;
 }
 
 

src/loop.c

@@ -45,8 +45,9 @@ void loop_send_probes()
 	     fd = rfd->fd;
 	   }
 
-	 while (sendto(fd, daemon->packet, len, 0, &serv->addr.sa, sa_len(&serv->addr)) == -1 && retry_send());
-
+	 while (retry_send(sendto(fd, daemon->packet, len, 0, 
+				  &serv->addr.sa, sa_len(&serv->addr))));
+	 
 	 free_rfd(rfd);
        }
 }

src/netlink.c

@@ -169,10 +169,10 @@ int iface_enumerate(int family, void *parm, int (*callback)())
   req.g.rtgen_family = family; 
 
   /* Don't block in recvfrom if send fails */
-  while((len = sendto(daemon->netlinkfd, (void *)&req, sizeof(req), 0, 
-		      (struct sockaddr *)&addr, sizeof(addr))) == -1 && retry_send());
-  
-  if (len == -1)
+  while(retry_send(sendto(daemon->netlinkfd, (void *)&req, sizeof(req), 0, 
+			  (struct sockaddr *)&addr, sizeof(addr))));
+
+  if (errno != 0)
     return 0;
     
   while (1)

src/radv.c

@@ -479,8 +479,9 @@ static void send_ra(time_t now, int iface, char *iface_name, struct in6_addr *de
       setsockopt(daemon->icmp6fd, IPPROTO_IPV6, IPV6_MULTICAST_IF, &iface, sizeof(iface));
     }
   
-  while (sendto(daemon->icmp6fd, daemon->outpacket.iov_base, save_counter(0), 0, 
-		(struct sockaddr *)&addr, sizeof(addr)) == -1 && retry_send());
+  while (retry_send(sendto(daemon->icmp6fd, daemon->outpacket.iov_base, 
+			   save_counter(0), 0, (struct sockaddr *)&addr, 
+			   sizeof(addr))));
   
 }
 

src/util.c

@@ -569,17 +569,27 @@ void bump_maxfd(int fd, int *max)
     *max = fd;
 }
 
-int retry_send(void)
+/* rc is return from sendto and friends.
+   Return 1 if we should retry.
+   Set errno to zero if we succeeded. */
+int retry_send(ssize_t rc)
 {
+  static int retries = 0;
+  struct timespec waiter;
+  
+  if (rc != -1)
+    {
+      retries = 0;
+      errno = 0;
+      return 0;
+    }
+  
   /* Linux kernels can return EAGAIN in perpetuity when calling
      sendmsg() and the relevant interface has gone. Here we loop
      retrying in EAGAIN for 1 second max, to avoid this hanging 
      dnsmasq. */
 
-  static int retries = 0;
-  struct timespec waiter;
-
-   if (errno == EAGAIN || errno == EWOULDBLOCK)
+  if (errno == EAGAIN || errno == EWOULDBLOCK)
      {
        waiter.tv_sec = 0;
        waiter.tv_nsec = 10000;
@@ -587,13 +597,13 @@ int retry_send(void)
        if (retries++ < 1000)
 	 return 1;
      }
-
-   retries = 0;
-   
-   if (errno == EINTR)
-     return 1;
-   
-   return 0;
+  
+  retries = 0;
+  
+  if (errno == EINTR)
+    return 1;
+  
+  return 0;
 }
 
 int read_write(int fd, unsigned char *packet, int size, int rw)
@@ -602,22 +612,21 @@ int read_write(int fd, unsigned char *packet, int size, int rw)
   
   for (done = 0; done < size; done += n)
     {
-    retry:
-      if (rw)
-        n = read(fd, &packet[done], (size_t)(size - done));
-      else
-        n = write(fd, &packet[done], (size_t)(size - done));
-
-      if (n == 0)
-        return 0;
-      else if (n == -1)
-        {
-          if (retry_send() || errno == ENOMEM || errno == ENOBUFS)
-            goto retry;
-          else
-            return 0;
-        }
+      do { 
+	if (rw)
+	  n = read(fd, &packet[done], (size_t)(size - done));
+	else
+	  n = write(fd, &packet[done], (size_t)(size - done));
+	
+	if (n == 0)
+	  return 0;
+	
+      } while (retry_send(n) || errno == ENOMEM || errno == ENOBUFS);
+
+      if (errno != 0)
+	return 0;
     }
+     
   return 1;
 }