o If we come out of select() with only write descriptors that

  end up writing zero bytes, sleep for 1/10 of a second so that
  we don't end up using up too much cpu.
  This should only ever happen on systems that wrongly report a
  descriptor as writable despite the tty buffer being full.
  Discussed with: Jeff Evarts

o Do an initial run-time check to see if select() alters the passed
  timeval.  This knowledge isn't yet used, but will be soon.

10 files changed, 71 insertions, 31 deletions

diff --git a/usr.sbin/ppp/Makefile b/usr.sbin/ppp/Makefile
index e4710dd..d2fdeb1 100644
--- a/usr.sbin/ppp/Makefile
+++ b/usr.sbin/ppp/Makefile
@@ -1,11 +1,11 @@
-#	$Id: Makefile,v 1.40 1998/06/07 17:08:42 brian Exp $
+#	$Id: Makefile,v 1.41 1998/06/09 05:36:37 imp Exp $
 
 PROG=	ppp
 SRCS=	arp.c async.c auth.c bundle.c ccp.c chap.c chat.c command.c \
 	datalink.c deflate.c defs.c filter.c fsm.c hdlc.c id.c ip.c \
 	ipcp.c iplist.c lcp.c link.c log.c lqr.c main.c mbuf.c modem.c \
-	mp.c pap.c physical.c pred.c prompt.c route.c server.c sig.c \
-	slcompress.c systems.c throughput.c timer.c tun.c vjcomp.c
+	mp.c pap.c physical.c pred.c probe.c prompt.c route.c server.c \
+	sig.c slcompress.c systems.c throughput.c timer.c tun.c vjcomp.c
 CFLAGS+=-Wall
 LDADD+= -lutil -lz
 DPADD+=	${LIBUTIL} ${LIBZ}
diff --git a/usr.sbin/ppp/bundle.c b/usr.sbin/ppp/bundle.c
index 49ba4de..d5ae0d5 100644
--- a/usr.sbin/ppp/bundle.c
+++ b/usr.sbin/ppp/bundle.c
@@ -23,7 +23,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: bundle.c,v 1.21 1998/06/20 00:19:32 brian Exp $
+ *	$Id: bundle.c,v 1.22 1998/06/20 01:36:38 brian Exp $
  */
 
 #include <sys/param.h>
@@ -679,11 +679,12 @@ bundle_DescriptorRead(struct descriptor *d, struct bundle *bundle,
   }
 }
 
-static void
+static int
 bundle_DescriptorWrite(struct descriptor *d, struct bundle *bundle,
                        const fd_set *fdset)
 {
   struct datalink *dl;
+  int result = 0;
 
   /* This is not actually necessary as struct mpserver doesn't Write() */
   if (descriptor_IsSet(&bundle->ncp.mp.server.desc, fdset))
@@ -691,7 +692,9 @@ bundle_DescriptorWrite(struct descriptor *d, struct bundle *bundle,
 
   for (dl = bundle->links; dl; dl = dl->next)
     if (descriptor_IsSet(&dl->desc, fdset))
-      descriptor_Write(&dl->desc, bundle, fdset);
+      result += descriptor_Write(&dl->desc, bundle, fdset);
+
+  return result;
 }
 
 void
diff --git a/usr.sbin/ppp/chat.c b/usr.sbin/ppp/chat.c
index 662b7fd..353bf77 100644
--- a/usr.sbin/ppp/chat.c
+++ b/usr.sbin/ppp/chat.c
@@ -23,7 +23,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: chat.c,v 1.47 1998/05/28 23:17:38 brian Exp $
+ *	$Id: chat.c,v 1.48 1998/06/15 19:06:38 brian Exp $
  */
 
 #include <sys/types.h>
@@ -464,10 +464,11 @@ chat_Read(struct descriptor *d, struct bundle *bundle, const fd_set *fdset)
   }
 }
 
-static void
+static int
 chat_Write(struct descriptor *d, struct bundle *bundle, const fd_set *fdset)
 {
   struct chat *c = descriptor2chat(d);
+  int result = 0;
 
   if (c->state == CHAT_SEND) {
     int wrote;
@@ -491,6 +492,7 @@ chat_Write(struct descriptor *d, struct bundle *bundle, const fd_set *fdset)
     }
 
     wrote = physical_Write(c->physical, c->argptr, c->arglen);
+    result = wrote ? 1 : 0;
     if (wrote == -1) {
       if (errno != EINTR)
         log_Printf(LogERROR, "chat_Write: %s\n", strerror(errno));
@@ -507,6 +509,8 @@ chat_Write(struct descriptor *d, struct bundle *bundle, const fd_set *fdset)
       c->arglen -= wrote;
     }
   }
+
+  return result;
 }
 
 void
diff --git a/usr.sbin/ppp/datalink.c b/usr.sbin/ppp/datalink.c
index 9923ec5..1b36120 100644
--- a/usr.sbin/ppp/datalink.c
+++ b/usr.sbin/ppp/datalink.c
@@ -23,7 +23,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: datalink.c,v 1.10 1998/06/16 07:15:16 brian Exp $
+ *	$Id: datalink.c,v 1.11 1998/06/20 00:19:35 brian Exp $
  */
 
 #include <sys/types.h>
@@ -363,10 +363,11 @@ datalink_Read(struct descriptor *d, struct bundle *bundle, const fd_set *fdset)
   }
 }
 
-static void
+static int
 datalink_Write(struct descriptor *d, struct bundle *bundle, const fd_set *fdset)
 {
   struct datalink *dl = descriptor2datalink(d);
+  int result = 0;
 
   switch (dl->state) {
     case DATALINK_CLOSED:
@@ -376,16 +377,18 @@ datalink_Write(struct descriptor *d, struct bundle *bundle, const fd_set *fdset)
     case DATALINK_HANGUP:
     case DATALINK_DIAL:
     case DATALINK_LOGIN:
-      descriptor_Write(&dl->chat.desc, bundle, fdset);
+      result = descriptor_Write(&dl->chat.desc, bundle, fdset);
       break;
 
     case DATALINK_READY:
     case DATALINK_LCP:
     case DATALINK_AUTH:
     case DATALINK_OPEN:
-      descriptor_Write(&dl->physical->desc, bundle, fdset);
+      result = descriptor_Write(&dl->physical->desc, bundle, fdset);
       break;
   }
+
+  return result;
 }
 
 static void
diff --git a/usr.sbin/ppp/descriptor.h b/usr.sbin/ppp/descriptor.h
index b78a1ac..98cda53 100644
--- a/usr.sbin/ppp/descriptor.h
+++ b/usr.sbin/ppp/descriptor.h
@@ -23,7 +23,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: descriptor.h,v 1.2 1998/05/21 21:45:08 brian Exp $
+ *	$Id: descriptor.h,v 1.3 1998/05/23 22:24:34 brian Exp $
  */
 
 #define PHYSICAL_DESCRIPTOR (1)
@@ -42,7 +42,7 @@ struct descriptor {
   int (*UpdateSet)(struct descriptor *, fd_set *, fd_set *, fd_set *, int *);
   int (*IsSet)(struct descriptor *, const fd_set *);
   void (*Read)(struct descriptor *, struct bundle *, const fd_set *);
-  void (*Write)(struct descriptor *, struct bundle *, const fd_set *);
+  int (*Write)(struct descriptor *, struct bundle *, const fd_set *);
 };
 
 #define descriptor_UpdateSet(d, r, w, e, n) ((*(d)->UpdateSet)(d, r, w, e, n))
diff --git a/usr.sbin/ppp/main.c b/usr.sbin/ppp/main.c
index ab0be06..372fa67 100644
--- a/usr.sbin/ppp/main.c
+++ b/usr.sbin/ppp/main.c
@@ -17,7 +17,7 @@
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
- * $Id: main.c,v 1.134 1998/06/16 19:40:27 brian Exp $
+ * $Id: main.c,v 1.135 1998/06/16 19:40:39 brian Exp $
  *
  *	TODO:
  */
@@ -40,6 +40,7 @@
 #include <termios.h>
 #include <unistd.h>
 
+#include "probe.h"
 #include "mbuf.h"
 #include "log.h"
 #include "defs.h"
@@ -442,7 +443,10 @@ static void
 DoLoop(struct bundle *bundle)
 {
   fd_set rfds, wfds, efds;
-  int i, nfds;
+  int i, nfds, nothing_done;
+  struct probe probe;
+
+  probe_Init(&probe);
 
   do {
     nfds = 0;
@@ -514,14 +518,32 @@ DoLoop(struct bundle *bundle)
     if (i <= nfds)
       break;
 
-    if (descriptor_IsSet(&server.desc, &rfds))
+    nothing_done = 1;
+
+    if (descriptor_IsSet(&server.desc, &rfds)) {
       descriptor_Read(&server.desc, bundle, &rfds);
+      nothing_done = 0;
+    }
+
+    if (descriptor_IsSet(&bundle->desc, &rfds)) {
+      descriptor_Read(&bundle->desc, bundle, &rfds);
+      nothing_done = 0;
+    }
 
     if (descriptor_IsSet(&bundle->desc, &wfds))
-      descriptor_Write(&bundle->desc, bundle, &wfds);
+      if (!descriptor_Write(&bundle->desc, bundle, &wfds) && nothing_done) {
+        /*
+         * This is disasterous.  The OS has told us that something is
+         * writable, and all our write()s have failed.  Rather than
+         * going back immediately to do our UpdateSet()s and select(),
+         * we sleep for a bit to avoid gobbling up all cpu time.
+         */
+        struct timeval t;
 
-    if (descriptor_IsSet(&bundle->desc, &rfds))
-      descriptor_Read(&bundle->desc, bundle, &rfds);
+        t.tv_sec = 0;
+        t.tv_usec = 100000;
+        select(0, NULL, NULL, NULL, &t);
+      }
 
   } while (bundle_CleanDatalinks(bundle), !bundle_IsDead(bundle));
 
diff --git a/usr.sbin/ppp/modem.c b/usr.sbin/ppp/modem.c
index 605289e..fbe6bcc 100644
--- a/usr.sbin/ppp/modem.c
+++ b/usr.sbin/ppp/modem.c
@@ -17,7 +17,7 @@
  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  *
- * $Id: modem.c,v 1.91 1998/06/16 19:40:39 brian Exp $
+ * $Id: modem.c,v 1.92 1998/06/18 22:43:18 brian Exp $
  *
  *  TODO:
  */
@@ -78,8 +78,8 @@
 #include "systems.h"
 
 
-static void modem_DescriptorWrite(struct descriptor *, struct bundle *,
-                                  const fd_set *);
+static int modem_DescriptorWrite(struct descriptor *, struct bundle *,
+                                 const fd_set *);
 static void modem_DescriptorRead(struct descriptor *, struct bundle *,
                                  const fd_set *);
 static int modem_UpdateSet(struct descriptor *, fd_set *, fd_set *, fd_set *,
@@ -831,12 +831,12 @@ modem_LogicalClose(struct physical *modem)
   modem->name.base = modem->name.full;
 }
 
-static void
+static int
 modem_DescriptorWrite(struct descriptor *d, struct bundle *bundle,
                       const fd_set *fdset)
 {
   struct physical *modem = descriptor2physical(d);
-  int nb, nw;
+  int nb, nw, result = 0;
 
   if (modem->out == NULL)
     modem->out = link_Dequeue(&modem->link);
@@ -851,14 +851,19 @@ modem_DescriptorWrite(struct descriptor *d, struct bundle *bundle,
       modem->out->offset += nw;
       if (modem->out->cnt == 0)
 	modem->out = mbuf_FreeSeg(modem->out);
+      result = 1;
     } else if (nw < 0) {
       if (errno != EAGAIN) {
 	log_Printf(LogPHASE, "%s: write (%d): %s\n", modem->link.name,
                    modem->fd, strerror(errno));
         datalink_Down(modem->dl, CLOSE_NORMAL);
       }
+      result = 1;
     }
+    /* else we shouldn't really have been called !  select() is broken ! */
   }
+
+  return result;
 }
 
 int
diff --git a/usr.sbin/ppp/mp.c b/usr.sbin/ppp/mp.c
index 642d535..4c9ff8b 100644
--- a/usr.sbin/ppp/mp.c
+++ b/usr.sbin/ppp/mp.c
@@ -23,7 +23,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: mp.c,v 1.9 1998/06/16 19:40:40 brian Exp $
+ *	$Id: mp.c,v 1.10 1998/06/20 00:19:42 brian Exp $
  */
 
 #include <sys/types.h>
@@ -901,11 +901,12 @@ mpserver_Read(struct descriptor *d, struct bundle *bundle, const fd_set *fdset)
     close(fd);
 }
 
-static void
+static int
 mpserver_Write(struct descriptor *d, struct bundle *bundle, const fd_set *fdset)
 {
   /* We never want to write here ! */
   log_Printf(LogALERT, "mpserver_Write: Internal error: Bad call !\n");
+  return 0;
 }
 
 void
diff --git a/usr.sbin/ppp/prompt.c b/usr.sbin/ppp/prompt.c
index 7b7f17d..fdd59fc 100644
--- a/usr.sbin/ppp/prompt.c
+++ b/usr.sbin/ppp/prompt.c
@@ -23,7 +23,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: prompt.c,v 1.6 1998/06/16 07:15:11 brian Exp $
+ *	$Id: prompt.c,v 1.7 1998/06/16 19:40:40 brian Exp $
  */
 
 #include <sys/param.h>
@@ -276,11 +276,12 @@ prompt_Read(struct descriptor *d, struct bundle *bundle, const fd_set *fdset)
   }
 }
 
-static void
+static int
 prompt_Write(struct descriptor *d, struct bundle *bundle, const fd_set *fdset)
 {
   /* We never want to write here ! */
   log_Printf(LogALERT, "prompt_Write: Internal error: Bad call !\n");
+  return 0;
 }
 
 struct prompt *
diff --git a/usr.sbin/ppp/server.c b/usr.sbin/ppp/server.c
index a780319..b8dd938 100644
--- a/usr.sbin/ppp/server.c
+++ b/usr.sbin/ppp/server.c
@@ -23,7 +23,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: server.c,v 1.19 1998/05/23 22:24:50 brian Exp $
+ *	$Id: server.c,v 1.20 1998/06/16 19:40:41 brian Exp $
  */
 
 #include <sys/types.h>
@@ -175,11 +175,12 @@ server_Read(struct descriptor *d, struct bundle *bundle, const fd_set *fdset)
       descriptor_Read(&p->desc, bundle, fdset);
 }
 
-static void
+static int
 server_Write(struct descriptor *d, struct bundle *bundle, const fd_set *fdset)
 {
   /* We never want to write here ! */
   log_Printf(LogALERT, "server_Write: Internal error: Bad call !\n");
+  return 0;
 }
 
 struct server server = {