/*
* Wait on epoll set. This is a blocking call of timeout value.
*/
int compat_epoll_wait(struct lttng_poll_event *events, int timeout)
{
int ret;
uint32_t new_size;
if (events == NULL || events->events == NULL) {
ERR("Wrong arguments in compat_epoll_wait");
goto error;
}
/*
* Resize if needed before waiting. We could either expand the array or
* shrink it down. It's important to note that after this step, we are
* ensured that the events argument of the epoll_wait call will be large
* enough to hold every possible returned events.
*/
if (events->nb_fd > events->alloc_size) {
/* Expand if the nb_fd is higher than the actual size. */
new_size = max_t(uint32_t,
1U << utils_get_count_order_u32(events->nb_fd),
events->alloc_size << 1UL);
} else if ((events->nb_fd << 1UL) <= events->alloc_size &&
events->nb_fd >= events->init_size) {
/* Shrink if nb_fd multiplied by two is <= than the actual size. */
new_size = max_t(uint32_t,
utils_get_count_order_u32(events->nb_fd) >> 1U,
events->alloc_size >> 1U);
} else {
/*
* Wait on epoll set. This is a blocking call of timeout value.
*/
int compat_epoll_wait(struct lttng_poll_event *events, int timeout)
{
int ret;
uint32_t new_size;
if (events == NULL || events->events == NULL) {
ERR("Wrong arguments in compat_epoll_wait");
goto error;
}
if (events->nb_fd == 0) {
errno = EINVAL;
return -1;
}
/*
* Resize if needed before waiting. We could either expand the array or
* shrink it down. It's important to note that after this step, we are
* ensured that the events argument of the epoll_wait call will be large
* enough to hold every possible returned events.
*/
new_size = 1U << utils_get_count_order_u32(events->nb_fd);
if (new_size != events->alloc_size && new_size >= events->init_size) {
ret = resize_poll_event(events, new_size);
if (ret < 0) {
/* ENOMEM problem at this point. */
goto error;
}
}
do {
ret = epoll_wait(events->epfd, events->events, events->nb_fd, timeout);
} while (ret == -1 && errno == EINTR);
if (ret < 0) {
/* At this point, every error is fatal */
PERROR("epoll_wait");
goto error;
}
/*
* Since the returned events are set sequentially in the "events" structure
* we only need to return the epoll_wait value and iterate over it.
*/
return ret;
error:
return -1;
}
/*
* Add fd to pollfd data structure with requested events.
*/
int compat_poll_add(struct lttng_poll_event *events, int fd,
uint32_t req_events)
{
int new_size, ret, i;
struct compat_poll_event_array *current;
if (events == NULL || events->current.events == NULL || fd < 0) {
ERR("Bad compat poll add arguments");
goto error;
}
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;
}
}
/* 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;
}
}
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;
error:
return -1;
}
/*
* Remove a fd from the pollfd structure.
*/
int compat_poll_del(struct lttng_poll_event *events, int fd)
{
int new_size, i, count = 0, ret;
struct compat_poll_event_array *current;
if (events == NULL || events->current.events == NULL || fd < 0) {
ERR("Wrong arguments for poll del");
goto error;
}
/* Ease our life a bit. */
current = &events->current;
for (i = 0; i < current->nb_fd; i++) {
/* Don't put back the fd we want to delete */
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->need_update = 1;
return 0;
error:
return -1;
}
