Slight update before release.

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

.travis.yml

@@ -2,7 +2,6 @@
 language: c
 compiler:
   - gcc
-  - clang
 
 env:
   global:

CHANGELOG.md

@@ -3,6 +3,28 @@ Change Log
 
 All notable changes to the project are documented in this file.
 
+
+[v1.1.0]
+--------
+
+Massively improved error handling.
+
+### Changes
+- Handle case when user closes a descriptor *before* stopping a watcher.
+- Handle `EPOLLHUP` and `EPOLLERR`.  Restart `epoll(7)` descriptor and
+  all watchers when an error count reaches a MAX value -- handles stale
+  descriptors or cases when kernel does not notice updated descriptors.
+- Return error when stopping a watcher fails.
+- Update [README.md] with new `uev_*_start()` functions.
+- Bump dev version to 1.1 due to the number of significant changes.
+
+### Fixes
+- Remove `test.c` from `DISTFILES` in `Makefile`.  You need the
+  comeplete sources to build the examples now.  Thanks to @karasz for
+  the heads up on this and the musl libc issue with missing `queue.h`!
+- Fix broken link to [v1.0.5] in this file.
+
+
 [v1.0.5]
 --------
 
@@ -85,8 +107,9 @@ v0.0.1 - 2012-03-17
 [Initial announcement] of [libuevent] by [Flemming Madsen] to the Lua
 users mailing list.
 
-
-[v1.0.4]: https://github.com/troglobit/libuev/compare/v1.0.4...v1.0.5
+[UNRELEASED]: https://github.com/troglobit/libuev/compare/v1.1,0...HEAD
+[v1.1.0]: https://github.com/troglobit/libuev/compare/v1.0.5...v1.1.0
+[v1.0.5]: https://github.com/troglobit/libuev/compare/v1.0.4...v1.0.5
 [v1.0.4]: https://github.com/troglobit/libuev/compare/v1.0.3...v1.0.4
 [v1.0.3]: https://github.com/troglobit/libuev/compare/v1.0.2...v1.0.3
 [v1.0.2]: https://github.com/troglobit/libuev/compare/v1.0.1...v1.0.2

Makefile

@@ -25,7 +25,7 @@
 .PHONY: all test clean joystick test examples
 
 #VERSION    = $(shell git tag -l | tail -1)
-VERSION    ?= 1.0.5
+VERSION    ?= 1.1.0
 NAME        = libuev
 PKG         = $(NAME)-$(VERSION)
 ARCHIVE     = $(PKG).tar.xz
@@ -46,7 +46,7 @@ prefix     ?= /usr/local
 libdir     ?= $(prefix)/lib
 datadir    ?= $(prefix)/share/doc/$(LIBNAME)
 incdir     ?= $(prefix)/include
-DISTFILES   = README CHANGELOG TODO LICENSE test.c
+DISTFILES   = README CHANGELOG TODO LICENSE
 HEADER      = uev.h
 
 OBJS       := uev.o io.o timer.o signal.o

README.md

@@ -24,14 +24,14 @@ often swing without consideration.  Event loops and non-blocking I/O is
 often a far easier approach, as well as less error prone.
 
 The purpose of many applications is, with a little logic sprinkled on
-top, to act upon: network packets entering an interface, timeouts
-expiring, mouse clicks, or other types of events.  Such applications are
-often very well suited to use an event loop.
+top, to act on network packets entering an interface, timeouts expiring,
+mouse clicks, or other types of events.  Such applications are often
+very well suited to use an event loop.
 
 Applications that need to churn massively parallel algorithms are more
 suitable for running multiple (independent) threads on several CPU
 cores.  However, threaded applications must deal with the side effects
-of concurrency, like: race conditions, deadlocks, live locks, etc.
+of concurrency, like race conditions, deadlocks, live locks, etc.
 Writing error free threaded applications is hard, debugging them can be
 even harder.
 
@@ -65,31 +65,34 @@ Here is the interface to [libuEv].  It handles three different types of
 events: I/O (files, sockets, message queues, etc.), timers, and signals.
 
 ```C
-/* Callback example, arg is passed from watcher's *_init()
- * w->fd holds the file descriptor, events is set by libuEv
- * to indicate if any of UEV_READ and/or UEV_WRITE is ready.
- */
-void callback(uev_ctx_t *ctx, uev_t *w, void *arg, int events);
+    /* Callback example, arg is passed from watcher's *_init()
+     * w->fd holds the file descriptor, events is set by libuEv
+     * to indicate if any of UEV_READ and/or UEV_WRITE is ready.
+     */
+    void callback       (uev_ctx_t *ctx, uev_t *w, void *arg, int events);
 
-/* Event loop functions, notice use of flags! */
-int uev_init       (uev_ctx_t *ctx);
-int uev_exit       (uev_ctx_t *ctx);
-int uev_run        (uev_ctx_t *ctx, int flags);         /* UEV_NONE, UEV_ONCE, and/or UEV_NONBLOCK */
-
-/* I/O watcher:     fd is non-blocking, events is UEV_READ and/or UEV_WRITE */
-int uev_io_init    (uev_ctx_t *ctx, uev_t *w, uev_cb_t *cb, void *arg, int fd, int events);
-int uev_io_set     (uev_t *w, int fd, int events);
-int uev_io_stop    (uev_t *w);
-
-/* Timer watcher:   timeout and period in milliseconds */
-int uev_timer_init (uev_ctx_t *ctx, uev_t *w, uev_cb_t *cb, void *arg, int timeout, int period);
-int uev_timer_set  (uev_t *w, int timeout, int period); /* Change timeout or period */
-int uev_timer_stop (uev_t *w);                          /* Stop a timer */
-
-/* Signal watcher:  signo is the signal to wait for, e.g., SIGTERM */
-int uev_signal_init(uev_ctx_t *ctx, uev_t *w, uev_cb_t *cb, void *arg, int signo);
-int uev_signal_set (uev_t *w, int signo);               /* Change signal to wait for */
-int uev_signal_stop(uev_t *w);                          /* Stop signal watcher */
+    /* Event loop functions, notice use of flags! */
+    int uev_init        (uev_ctx_t *ctx);
+    int uev_exit        (uev_ctx_t *ctx);
+    int uev_run         (uev_ctx_t *ctx, int flags);         /* UEV_NONE, UEV_ONCE, and/or UEV_NONBLOCK */
+    
+    /* I/O watcher:     fd is non-blocking, events is UEV_READ and/or UEV_WRITE */
+    int uev_io_init     (uev_ctx_t *ctx, uev_t *w, uev_cb_t *cb, void *arg, int fd, int events);
+    int uev_io_set      (uev_t *w, int fd, int events);
+    int uev_io_start    (uev_t *w);
+    int uev_io_stop     (uev_t *w);
+    
+    /* Timer watcher:   timeout and period in milliseconds */
+    int uev_timer_init  (uev_ctx_t *ctx, uev_t *w, uev_cb_t *cb, void *arg, int timeout, int period);
+    int uev_timer_set   (uev_t *w, int timeout, int period); /* Change timeout or period */
+    int uev_timer_start (uev_t *w);                          /* Restart a stopped timer */
+    int uev_timer_stop  (uev_t *w);                          /* Stop a timer */
+    
+    /* Signal watcher:  signo is the signal to wait for, e.g., SIGTERM */
+    int uev_signal_init (uev_ctx_t *ctx, uev_t *w, uev_cb_t *cb, void *arg, int signo);
+    int uev_signal_set  (uev_t *w, int signo);               /* Change signal to wait for */
+    int uev_signal_start(uev_t *w);                          /* Restart a stopped signal watcher */
+    int uev_signal_stop (uev_t *w);                          /* Stop signal watcher */
 ```
 
 To be able to set up callbacks to events the developer first need to
@@ -108,6 +111,10 @@ With `flags` set to `UEV_ONCE` the event loop returns after having
 served the first event.  If `flags` is set to `UEV_ONCE | UEV_NONBLOCK`
 the event loop returns immediately if no event is available.
 
+In the case of errors, stream close, or peer shutdown libuEv handles
+much internally, but also lets the callback run.  This is useful for
+stateful connections to be able to detect EOF.
+
 Summary:
 
 1. Prepare an event context with `uev_init()`
@@ -120,7 +127,11 @@ Summary:
 bugs in event driven applications are due to sockets and files being
 opened in blocking mode.  Be careful out there!
 
-**Note 2:** As mentioned above, a certain amount of care is needed when
+**Note 2:** When closing a descriptor or socket, make sure to first stop
+  your watcher, if possible.  This will help prevent any nasty side
+  effects on your program.
+
+**Note 3:** As mentioned above, a certain amount of care is needed when
 dealing with signalfd.  This means that if your application, for
 instance, uses `system()` you must redesign that to use `fork()`, and
 then in the child, unblock all signals blocked by your parent process,

examples/signal.c

@@ -103,6 +103,8 @@ static void work_cb(uev_ctx_t *UNUSED(ctx), uev_t *UNUSED(w), void *arg, int UNU
 		printf("Child exited normally => %d\n", WEXITSTATUS(status));
 	else if (WCOREDUMP(status))
 		printf("Child crashed!\n");
+	else
+		printf("Child did not exit normally!\n");
 }
 
 static void exit_cb(uev_ctx_t *ctx, uev_t *UNUSED(w), void *UNUSED(arg), int UNUSED(events))

io.c

@@ -62,11 +62,8 @@ int uev_io_init(uev_ctx_t *ctx, uev_t *w, uev_cb_t *cb, void *arg, int fd, int e
  */
 int uev_io_set(uev_t *w, int fd, int events)
 {
-	if (uev_io_stop(w))
-		return -1;
-
-	/* Remove from internal list */
-	LIST_REMOVE(w, link);
+	/* Ignore any errors, only to clean up anything lingering ... */
+	uev_io_stop(w);
 
 	return uev_io_init(w->ctx, w, (uev_cb_t *)w->cb, w->arg, fd, events);
 }
@@ -90,9 +87,7 @@ int uev_io_start(uev_t *w)
  */
 int uev_io_stop(uev_t *w)
 {
-	int status = uev_watcher_stop(w);
-
-	return status;
+	return uev_watcher_stop(w);
 }
 
 /**

uev.c

@@ -24,6 +24,7 @@
  */
 
 #include <errno.h>
+#include <fcntl.h>		/* O_CLOEXEC */
 #include <string.h>		/* memset() */
 #include <sys/epoll.h>
 #include <sys/signalfd.h>	/* struct signalfd_siginfo */
@@ -33,6 +34,28 @@
 
 #define UNUSED(arg) arg __attribute__ ((unused))
 
+
+static int _init(uev_ctx_t *ctx, int close_old)
+{
+	int fd = epoll_create1(O_CLOEXEC);
+
+	if (fd < 0)
+		return -1;
+
+	if (close_old)
+		close(ctx->fd);
+
+	ctx->fd = fd;
+
+	return 0;
+}
+
+/* Simple check if a descriptor is still valid in the kernel */
+static int is_valid_fd(int fd)
+{
+    return fcntl(fd, F_GETFL) != -1 || errno != EBADF;
+}
+
 /* Private to libuEv, do not use directly! */
 int uev_watcher_init(uev_ctx_t *ctx, uev_t *w, uev_type_t type, uev_cb_t *cb, void *arg, int fd, int events)
 {
@@ -41,16 +64,14 @@ int uev_watcher_init(uev_ctx_t *ctx, uev_t *w, uev_type_t type, uev_cb_t *cb, vo
 		return -1;
 	}
 
-	memset(w, 0, sizeof(*w));
 	w->ctx    = ctx;
-	w->fd     = fd;
 	w->type   = type;
+	w->active = 0;
+	w->fd     = fd;
 	w->cb     = (void *)cb;
 	w->arg    = arg;
 	w->events = events;
 
-	LIST_INSERT_HEAD(&w->ctx->watchers, w, link);
-
 	return 0;
 }
 
@@ -67,13 +88,16 @@ int uev_watcher_start(uev_t *w)
 	if (w->active)
 		return 0;
 
-	ev.events   = w->events;
+	ev.events   = w->events | EPOLLRDHUP;
 	ev.data.ptr = w;
 	if (epoll_ctl(w->ctx->fd, EPOLL_CTL_ADD, w->fd, &ev) < 0)
 		return -1;
 
 	w->active = 1;
 
+	/* Add to internal list for bookkeeping */
+	LIST_INSERT_HEAD(&w->ctx->watchers, w, link);
+
 	return 0;
 }
 
@@ -88,10 +112,15 @@ int uev_watcher_stop(uev_t *w)
 	if (!w->active)
 		return 0;
 
-	/* Remove from kernel */
-	epoll_ctl(w->ctx->fd, EPOLL_CTL_DEL, w->fd, NULL);
 	w->active = 0;
 
+	/* Remove from internal list */
+	LIST_REMOVE(w, link);
+
+	/* Remove from kernel */
+	if (epoll_ctl(w->ctx->fd, EPOLL_CTL_DEL, w->fd, NULL) < 0)
+		return -1;
+
 	return 0;
 }
 
@@ -103,17 +132,15 @@ int uev_watcher_stop(uev_t *w)
  */
 int uev_init(uev_ctx_t *ctx)
 {
-	int fd;
-
-	fd = epoll_create(1);
-	if (fd < 0)
+	if (!ctx) {
+		errno = EINVAL;
 		return -1;
+	}
 
 	memset(ctx, 0, sizeof(*ctx));
-	ctx->fd = fd;
 	LIST_INIT(&ctx->watchers);
 
-	return 0;
+	return _init(ctx, 0);
 }
 
 /**
@@ -206,20 +233,54 @@ int uev_run(uev_ctx_t *ctx, int flags)
 
 			if (EINTR == errno)
 				continue; /* Signalled, try again */
-		exit:
-			result = -1;
-			ctx->running = 0;
-			break;
+
+			/* Unrecoverable error, cleanup and exit with error. */
+			uev_exit(ctx);
+			return -1;
 		}
 
 		for (i = 0; ctx->running && i < nfds; i++) {
 			w = (uev_t *)events[i].data.ptr;
 
+			if (events[i].events & (EPOLLHUP | EPOLLERR)) {
+				ctx->errors++;
+
+				if (ctx->errors >= 42) {
+					uev_t *tmp, *retry = w;;
+
+					/* If not valid anymore, try to remove, ignore any errors. */
+					if (!is_valid_fd(w->fd))
+						uev_watcher_stop(w);
+
+					/* Must recreate epoll fd now ... */
+					if (_init(ctx, 1)) {
+						uev_exit(ctx);
+						return -2;
+					}
+
+					/* Restart watchers in new efd */
+					LIST_FOREACH_SAFE(w, &ctx->watchers, link, tmp) {
+						if (w->active) {
+							w->active = 0;
+							LIST_REMOVE(w, link);
+							uev_watcher_start(w);
+						}
+					}
+					uev_watcher_start(retry);
+
+					/* New efd, restart everything! */
+					ctx->errors = 0;
+					continue;
+				}
+			}
+
 			if (UEV_TIMER_TYPE == w->type) {
 				uint64_t exp;
 
-				if (read(w->fd, &exp, sizeof(exp)) != sizeof(exp))
-					goto exit;
+				if (read(w->fd, &exp, sizeof(exp)) != sizeof(exp)) {
+					uev_exit(ctx);
+					return -3;
+				}
 
 				if (!w->period)
 					w->timeout = 0;
@@ -229,8 +290,10 @@ int uev_run(uev_ctx_t *ctx, int flags)
 				struct signalfd_siginfo fdsi;
 				ssize_t sz = sizeof(fdsi);
 
-				if (read(w->fd, &fdsi, sz) != sz)
-					goto exit;
+				if (read(w->fd, &fdsi, sz) != sz) {
+					uev_exit(ctx);
+					return -4;
+				}
 			}
 
 			if (w->cb)

uev.h

@@ -57,6 +57,7 @@ struct uev;
 typedef struct {
 	int             running;
 	int             fd;	/* For epoll() */
+	uint32_t        errors;
 	LIST_HEAD(,uev) watchers;
 } uev_ctx_t;