X-Git-Url: https://arthur.barton.de/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=libevent%2Fkqueue.c;h=51984a4e41d373f94886f2f755179278a706424f;hb=d2968df026cd9971caeab102f9348152b08b9132;hp=920129826f46a6dbe009c3c6d095f8e564e69bee;hpb=b0bcb8f6b0571592a50ce039882c9319e012a270;p=netatalk.git

diff --git a/libevent/kqueue.c b/libevent/kqueue.c
index 92012982..51984a4e 100644
--- a/libevent/kqueue.c
+++ b/libevent/kqueue.c
@@ -2,7 +2,7 @@
 
 /*
  * Copyright 2000-2007 Niels Provos <provos@citi.umich.edu>
- * Copyright 2007-2010 Niels Provos and Nick Mathewson
+ * Copyright 2007-2012 Niels Provos and Nick Mathewson
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -51,8 +51,10 @@
  * easy way to tell them apart via autoconf, so we need to use OS macros. */
 #if defined(_EVENT_HAVE_INTTYPES_H) && !defined(__OpenBSD__) && !defined(__FreeBSD__) && !defined(__darwin__) && !defined(__APPLE__)
 #define PTR_TO_UDATA(x)	((intptr_t)(x))
+#define INT_TO_UDATA(x) ((intptr_t)(x))
 #else
 #define PTR_TO_UDATA(x)	(x)
+#define INT_TO_UDATA(x) ((void*)(x))
 #endif
 
 #include "event-internal.h"
@@ -169,15 +171,20 @@ kq_sighandler(int sig)
 	/* Do nothing here */
 }
 
+#define ADD_UDATA 0x30303
+
 static void
 kq_setup_kevent(struct kevent *out, evutil_socket_t fd, int filter, short change)
 {
-	memset(out, 0, sizeof(out));
+	memset(out, 0, sizeof(struct kevent));
 	out->ident = fd;
 	out->filter = filter;
 
 	if (change & EV_CHANGE_ADD) {
 		out->flags = EV_ADD;
+		/* We set a magic number here so that we can tell 'add'
+		 * errors from 'del' errors. */
+		out->udata = INT_TO_UDATA(ADD_UDATA);
 		if (change & EV_ET)
 			out->flags |= EV_CLEAR;
 #ifdef NOTE_EOF
@@ -228,6 +235,23 @@ kq_build_changes_list(const struct event_changelist *changelist,
 	return n_changes;
 }
 
+static int
+kq_grow_events(struct kqop *kqop, size_t new_size)
+{
+	struct kevent *newresult;
+
+	newresult = mm_realloc(kqop->events,
+	    new_size * sizeof(struct kevent));
+
+	if (newresult) {
+		kqop->events = newresult;
+		kqop->events_size = new_size;
+		return 0;
+	} else {
+		return -1;
+	}
+}
+
 static int
 kq_dispatch(struct event_base *base, struct timeval *tv)
 {
@@ -255,6 +279,25 @@ kq_dispatch(struct event_base *base, struct timeval *tv)
 	changes = kqop->changes;
 	kqop->changes = NULL;
 
+	/* Make sure that 'events' is at least as long as the list of changes:
+	 * otherwise errors in the changes can get reported as a -1 return
+	 * value from kevent() rather than as EV_ERROR events in the events
+	 * array.
+	 *
+	 * (We could instead handle -1 return values from kevent() by
+	 * retrying with a smaller changes array or a larger events array,
+	 * but this approach seems less risky for now.)
+	 */
+	if (kqop->events_size < n_changes) {
+		int new_size = kqop->events_size;
+		do {
+			new_size *= 2;
+		} while (new_size < n_changes);
+
+		kq_grow_events(kqop, new_size);
+		events = kqop->events;
+	}
+
 	EVBASE_RELEASE_LOCK(base, th_base_lock);
 
 	res = kevent(kqop->kq, changes, n_changes,
@@ -280,27 +323,52 @@ kq_dispatch(struct event_base *base, struct timeval *tv)
 		int which = 0;
 
 		if (events[i].flags & EV_ERROR) {
-			/*
-			 * Error messages that can happen, when a delete fails.
-			 *   EBADF happens when the file descriptor has been
-			 *   closed,
-			 *   ENOENT when the file descriptor was closed and
-			 *   then reopened.
-			 *   EINVAL for some reasons not understood; EINVAL
-			 *   should not be returned ever; but FreeBSD does :-\
-			 * An error is also indicated when a callback deletes
-			 * an event we are still processing.  In that case
-			 * the data field is set to ENOENT.
-			 */
-			if (events[i].data == EBADF ||
-			    events[i].data == EINVAL ||
-			    events[i].data == ENOENT)
+			switch (events[i].data) {
+
+			/* Can occur on delete if we are not currently
+			 * watching any events on this fd.  That can
+			 * happen when the fd was closed and another
+			 * file was opened with that fd. */
+			case ENOENT:
+			/* Can occur for reasons not fully understood
+			 * on FreeBSD. */
+			case EINVAL:
 				continue;
-			errno = events[i].data;
-			return (-1);
-		}
 
-		if (events[i].filter == EVFILT_READ) {
+			/* Can occur on a delete if the fd is closed. */
+			case EBADF:
+				/* XXXX On NetBSD, we can also get EBADF if we
+				 * try to add the write side of a pipe, but
+				 * the read side has already been closed.
+				 * Other BSDs call this situation 'EPIPE'. It
+				 * would be good if we had a way to report
+				 * this situation. */
+				continue;
+			/* These two can occur on an add if the fd was one side
+			 * of a pipe, and the other side was closed. */
+			case EPERM:
+			case EPIPE:
+				/* Report read events, if we're listening for
+				 * them, so that the user can learn about any
+				 * add errors.  (If the operation was a
+				 * delete, then udata should be cleared.) */
+				if (events[i].udata) {
+					/* The operation was an add:
+					 * report the error as a read. */
+					which |= EV_READ;
+					break;
+				} else {
+					/* The operation was a del:
+					 * report nothing. */
+					continue;
+				}
+
+			/* Other errors shouldn't occur. */
+			default:
+				errno = events[i].data;
+				return (-1);
+			}
+		} else if (events[i].filter == EVFILT_READ) {
 			which |= EV_READ;
 		} else if (events[i].filter == EVFILT_WRITE) {
 			which |= EV_WRITE;
@@ -319,17 +387,9 @@ kq_dispatch(struct event_base *base, struct timeval *tv)
 	}
 
 	if (res == kqop->events_size) {
-		struct kevent *newresult;
-		int size = kqop->events_size;
 		/* We used all the events space that we have. Maybe we should
 		   make it bigger. */
-		size *= 2;
-		newresult = mm_realloc(kqop->events,
-		    size * sizeof(struct kevent));
-		if (newresult) {
-			kqop->events = newresult;
-			kqop->events_size = size;
-		}
+		kq_grow_events(kqop, kqop->events_size * 2);
 	}
 
 	return (0);