X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Fcompat%2Fcompat-poll.c;h=7d4d0e1334ef1dc2abba28f9e694d2ce8052d1ea;hp=7b15c737e6a0333ce5044ce2402d62d35aa1f643;hb=c607fe035ea8821a8f4c6ab6f3467ec726e36a63;hpb=990570edd474b304d4c935d82be6201d872025e4

diff --git a/src/common/compat/compat-poll.c b/src/common/compat/compat-poll.c
index 7b15c737e..7d4d0e133 100644
--- a/src/common/compat/compat-poll.c
+++ b/src/common/compat/compat-poll.c
@@ -1,55 +1,148 @@
 /*
  * Copyright (C)  2011 - David Goulet <david.goulet@polymtl.ca>
  *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by the Free
- * Software Foundation; only version 2 of the License.
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2 only,
+ * as published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  * more details.
  *
- * You should have received a copy of the GNU General Public License along with
- * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
- * Place - Suite 330, Boston, MA  02111-1307, USA.
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
+#define _LGPL_SOURCE
+#include <assert.h>
 #include <stdlib.h>
 #include <sys/resource.h>
 #include <sys/time.h>
 
-#include <lttngerr.h>
 #include <common/defaults.h>
+#include <common/error.h>
+#include <common/macros.h>
+#include <common/utils.h>
 
 #include "poll.h"
 
 unsigned int poll_max_size;
 
+/*
+ * Resize the epoll events structure of the new size.
+ *
+ * Return 0 on success or else -1 with the current events pointer untouched.
+ */
+static int resize_poll_event(struct compat_poll_event_array *array,
+		uint32_t new_size)
+{
+	struct pollfd *ptr;
+
+	assert(array);
+
+	/* Refuse to resize the array more than the max size. */
+	if (new_size > poll_max_size) {
+		goto error;
+	}
+
+	ptr = realloc(array->events, new_size * sizeof(*ptr));
+	if (ptr == NULL) {
+		PERROR("realloc epoll add");
+		goto error;
+	}
+	if (new_size > array->alloc_size) {
+		/* Zero newly allocated memory */
+		memset(ptr + array->alloc_size, 0,
+			(new_size - array->alloc_size) * sizeof(*ptr));
+	}
+	array->events = ptr;
+	array->alloc_size = new_size;
+
+	return 0;
+
+error:
+	return -1;
+}
+
+/*
+ * Update events with the current events object.
+ */
+static int update_current_events(struct lttng_poll_event *events)
+{
+	int ret;
+	struct compat_poll_event_array *current, *wait;
+
+	assert(events);
+
+	current = &events->current;
+	wait = &events->wait;
+
+	wait->nb_fd = current->nb_fd;
+	if (current->alloc_size != wait->alloc_size) {
+		ret = resize_poll_event(wait, current->alloc_size);
+		if (ret < 0) {
+			goto error;
+		}
+	}
+	memcpy(wait->events, current->events,
+			current->nb_fd * sizeof(*current->events));
+
+	/* Update is done. */
+	events->need_update = 0;
+
+	return 0;
+
+error:
+	return -1;
+}
+
 /*
  * Create pollfd data structure.
  */
 int compat_poll_create(struct lttng_poll_event *events, int size)
 {
+	struct compat_poll_event_array *current, *wait;
+
 	if (events == NULL || size <= 0) {
 		ERR("Wrong arguments for poll create");
 		goto error;
 	}
 
+	if (!poll_max_size) {
+		if (lttng_poll_set_max_size()) {
+			goto error;
+		}
+	}
+
 	/* Don't bust the limit here */
 	if (size > poll_max_size) {
 		size = poll_max_size;
 	}
 
+	/* Reset everything before begining the allocation. */
+	memset(events, 0, sizeof(struct lttng_poll_event));
+
+	current = &events->current;
+	wait = &events->wait;
+
 	/* This *must* be freed by using lttng_poll_free() */
-	events->events = zmalloc(size * sizeof(struct pollfd));
-	if (events->events == NULL) {
-		perror("zmalloc struct pollfd");
+	wait->events = zmalloc(size * sizeof(struct pollfd));
+	if (wait->events == NULL) {
+		PERROR("zmalloc struct pollfd");
 		goto error;
 	}
 
-	events->events_size = size;
-	events->nb_fd = 0;
+	wait->alloc_size = wait->init_size = size;
+
+	current->events = zmalloc(size * sizeof(struct pollfd));
+	if (current->events == NULL) {
+		PERROR("zmalloc struct current pollfd");
+		goto error;
+	}
+
+	current->alloc_size = current->init_size = size;
 
 	return 0;
 
@@ -63,31 +156,39 @@ error:
 int compat_poll_add(struct lttng_poll_event *events, int fd,
 		uint32_t req_events)
 {
-	int new_size;
-	struct pollfd *ptr;
+	int new_size, ret, i;
+	struct compat_poll_event_array *current;
 
-	if (events == NULL || events->events == NULL || fd < 0) {
+	if (events == NULL || events->current.events == NULL || fd < 0) {
 		ERR("Bad compat poll add arguments");
 		goto error;
 	}
 
-	/* Reallocate pollfd structure by a factor of 2 if needed. */
-	if (events->nb_fd >= events->events_size) {
-		new_size = 2 * events->events_size;
-		ptr = realloc(events->events, new_size * sizeof(struct pollfd));
-		if (ptr == NULL) {
-			perror("realloc poll add");
+	current = &events->current;
+
+	/* Check if fd we are trying to add is already there. */
+	for (i = 0; i < current->nb_fd; i++) {
+		if (current->events[i].fd == fd) {
+			errno = EEXIST;
 			goto error;
 		}
-		events->events = ptr;
-		events->events_size = new_size;
 	}
 
-	events->events[events->nb_fd].fd = fd;
-	events->events[events->nb_fd].events = req_events;
-	events->nb_fd++;
+	/* Resize array if needed. */
+	new_size = 1U << utils_get_count_order_u32(current->nb_fd + 1);
+	if (new_size != current->alloc_size && new_size >= current->init_size) {
+		ret = resize_poll_event(current, new_size);
+		if (ret < 0) {
+			goto error;
+		}
+	}
 
-	DBG("fd %d of %d added to pollfd", fd, events->nb_fd);
+	current->events[current->nb_fd].fd = fd;
+	current->events[current->nb_fd].events = req_events;
+	current->nb_fd++;
+	events->need_update = 1;
+
+	DBG("fd %d of %d added to pollfd", fd, current->nb_fd);
 
 	return 0;
 
@@ -100,42 +201,39 @@ error:
  */
 int compat_poll_del(struct lttng_poll_event *events, int fd)
 {
-	int new_size, i, count = 0;
-	struct pollfd *old = NULL, *new = NULL;
+	int new_size, i, count = 0, ret;
+	struct compat_poll_event_array *current;
 
-	if (events == NULL || events->events == NULL || fd < 0) {
+	if (events == NULL || events->current.events == NULL || fd < 0) {
 		ERR("Wrong arguments for poll del");
 		goto error;
 	}
 
-	old = events->events;
-	new_size = events->events_size - 1;
-
-	/* Safety check on size */
-	if (new_size > poll_max_size) {
-		new_size = poll_max_size;
-	}
-
-	new = zmalloc(new_size * sizeof(struct pollfd));
-	if (new == NULL) {
-		perror("zmalloc poll del");
-		goto error;
-	}
+	/* Ease our life a bit. */
+	current = &events->current;
 
-	for (i = 0; i < events->events_size; i++) {
+	for (i = 0; i < current->nb_fd; i++) {
 		/* Don't put back the fd we want to delete */
-		if (old[i].fd != fd) {
-			new[count].fd = old[i].fd;
-			new[count].events = old[i].events;
+		if (current->events[i].fd != fd) {
+			current->events[count].fd = current->events[i].fd;
+			current->events[count].events = current->events[i].events;
 			count++;
 		}
 	}
+	/* No fd duplicate should be ever added into array. */
+	assert(current->nb_fd - 1 == count);
+	current->nb_fd = count;
+
+	/* Resize array if needed. */
+	new_size = 1U << utils_get_count_order_u32(current->nb_fd);
+	if (new_size != current->alloc_size && new_size >= current->init_size) {
+		ret = resize_poll_event(current, new_size);
+		if (ret < 0) {
+			goto error;
+		}
+	}
 
-	events->events_size = new_size;
-	events->events = new;
-	events->nb_fd--;
-
-	free(old);
+	events->need_update = 1;
 
 	return 0;
 
@@ -150,20 +248,41 @@ int compat_poll_wait(struct lttng_poll_event *events, int timeout)
 {
 	int ret;
 
-	if (events == NULL || events->events == NULL ||
-			events->events_size < events->nb_fd) {
+	if (events == NULL || events->current.events == NULL) {
 		ERR("poll wait arguments error");
 		goto error;
 	}
+	assert(events->current.nb_fd >= 0);
 
-	ret = poll(events->events, events->nb_fd, timeout);
+	if (events->current.nb_fd == 0) {
+		/* Return an invalid error to be consistent with epoll. */
+		errno = EINVAL;
+		events->wait.nb_fd = 0;
+		goto error;
+	}
+
+	if (events->need_update) {
+		ret = update_current_events(events);
+		if (ret < 0) {
+			errno = ENOMEM;
+			goto error;
+		}
+	}
+
+	do {
+		ret = poll(events->wait.events, events->wait.nb_fd, timeout);
+	} while (ret == -1 && errno == EINTR);
 	if (ret < 0) {
 		/* At this point, every error is fatal */
-		perror("poll wait");
+		PERROR("poll wait");
 		goto error;
 	}
 
-	return ret;
+	/*
+	 * poll() should always iterate on all FDs since we handle the pollset in
+	 * user space and after poll returns, we have to try every fd for a match.
+	 */
+	return events->wait.nb_fd;
 
 error:
 	return -1;
@@ -172,25 +291,23 @@ error:
 /*
  * Setup poll set maximum size.
  */
-void compat_poll_set_max_size(void)
+int compat_poll_set_max_size(void)
 {
-	int ret;
+	int ret, retval = 0;
 	struct rlimit lim;
 
-	/* Default value */
-	poll_max_size = DEFAULT_POLL_SIZE;
-
 	ret = getrlimit(RLIMIT_NOFILE, &lim);
 	if (ret < 0) {
-		perror("getrlimit poll RLIMIT_NOFILE");
-		return;
+		PERROR("getrlimit poll RLIMIT_NOFILE");
+		retval = -1;
+		goto end;
 	}
 
 	poll_max_size = lim.rlim_cur;
-	if (poll_max_size <= 0) {
-		/* Extra precaution */
+end:
+	if (poll_max_size == 0) {
 		poll_max_size = DEFAULT_POLL_SIZE;
 	}
-
 	DBG("poll set max size set to %u", poll_max_size);
+	return retval;
 }