the fd, we need to say op="MOD" and set events=the events we want to
remain. But if we want to delete the last event, we say op="DEL" and
set events=(any non-null pointer).
+
[*1] This MOD is only a guess. MOD might fail with ENOENT if the file was
closed and a new file was opened with the same fd. If so, we'll retry
with ADD.
int op, events = 0;
int idx;
- if (1) {
- idx = INDEX(ch);
- op = op_table[idx].op;
- events = op_table[idx].events;
+ idx = INDEX(ch);
+ op = op_table[idx].op;
+ events = op_table[idx].events;
- if (!events) {
- EVUTIL_ASSERT(op == 0);
- return 0;
- }
-
- if ((ch->read_change|ch->write_change) & EV_CHANGE_ET)
- events |= EPOLLET;
+ if (!events) {
+ EVUTIL_ASSERT(op == 0);
+ return 0;
+ }
- memset(&epev, 0, sizeof(epev));
- epev.data.fd = ch->fd;
- epev.events = events;
- if (epoll_ctl(epollop->epfd, op, ch->fd, &epev) == 0) {
- event_debug(("Epoll %s(%d) on fd %d okay. [old events were %d; read change was %d; write change was %d]",
- epoll_op_to_string(op),
- (int)epev.events,
- (int)ch->fd,
- ch->old_events,
- ch->read_change,
- ch->write_change));
- return 0;
- }
+ if ((ch->read_change|ch->write_change) & EV_CHANGE_ET)
+ events |= EPOLLET;
+
+ memset(&epev, 0, sizeof(epev));
+ epev.data.fd = ch->fd;
+ epev.events = events;
+ if (epoll_ctl(epollop->epfd, op, ch->fd, &epev) == 0) {
+ event_debug(("Epoll %s(%d) on fd %d okay. [old events were %d; read change was %d; write change was %d]",
+ epoll_op_to_string(op),
+ (int)epev.events,
+ (int)ch->fd,
+ ch->old_events,
+ ch->read_change,
+ ch->write_change));
+ return 0;
+ }
- switch (op) {
- case EPOLL_CTL_MOD:
- if (errno == ENOENT) {
- /* If a MOD operation fails with ENOENT, the
- * fd was probably closed and re-opened. We
- * should retry the operation as an ADD.
- */
- if (epoll_ctl(epollop->epfd, EPOLL_CTL_ADD, ch->fd, &epev) == -1) {
- event_warn("Epoll MOD(%d) on %d retried as ADD; that failed too",
- (int)epev.events, ch->fd);
- return -1;
- } else {
- event_debug(("Epoll MOD(%d) on %d retried as ADD; succeeded.",
- (int)epev.events,
- ch->fd));
- return 0;
- }
- }
- break;
- case EPOLL_CTL_ADD:
- if (errno == EEXIST) {
- /* If an ADD operation fails with EEXIST,
- * either the operation was redundant (as with a
- * precautionary add), or we ran into a fun
- * kernel bug where using dup*() to duplicate the
- * same file into the same fd gives you the same epitem
- * rather than a fresh one. For the second case,
- * we must retry with MOD. */
- if (epoll_ctl(epollop->epfd, EPOLL_CTL_MOD, ch->fd, &epev) == -1) {
- event_warn("Epoll ADD(%d) on %d retried as MOD; that failed too",
- (int)epev.events, ch->fd);
- return -1;
- } else {
- event_debug(("Epoll ADD(%d) on %d retried as MOD; succeeded.",
- (int)epev.events,
- ch->fd));
- return 0;
- }
- }
- break;
- case EPOLL_CTL_DEL:
- if (errno == ENOENT || errno == EBADF ||
- errno == EPERM) {
- /* If a delete fails with one of these errors,
- * that's fine too: we closed the fd before we
- * got around to calling epoll_dispatch. */
- event_debug(("Epoll DEL(%d) on fd %d gave %s: DEL was unnecessary.",
+ switch (op) {
+ case EPOLL_CTL_MOD:
+ if (errno == ENOENT) {
+ /* If a MOD operation fails with ENOENT, the
+ * fd was probably closed and re-opened. We
+ * should retry the operation as an ADD.
+ */
+ if (epoll_ctl(epollop->epfd, EPOLL_CTL_ADD, ch->fd, &epev) == -1) {
+ event_warn("Epoll MOD(%d) on %d retried as ADD; that failed too",
+ (int)epev.events, ch->fd);
+ return -1;
+ } else {
+ event_debug(("Epoll MOD(%d) on %d retried as ADD; succeeded.",
(int)epev.events,
- ch->fd,
- strerror(errno)));
+ ch->fd));
return 0;
- }
- break;
- default:
- break;
+ }
}
-
- if (1) {
- event_warn("Epoll %s(%d) on fd %d failed. Old events were %d; read change was %d (%s); write change was %d (%s)",
- epoll_op_to_string(op),
- (int)epev.events,
- ch->fd,
- ch->old_events,
- ch->read_change,
- change_to_string(ch->read_change),
- ch->write_change,
- change_to_string(ch->write_change));
+ break;
+ case EPOLL_CTL_ADD:
+ if (errno == EEXIST) {
+ /* If an ADD operation fails with EEXIST,
+ * either the operation was redundant (as with a
+ * precautionary add), or we ran into a fun
+ * kernel bug where using dup*() to duplicate the
+ * same file into the same fd gives you the same epitem
+ * rather than a fresh one. For the second case,
+ * we must retry with MOD. */
+ if (epoll_ctl(epollop->epfd, EPOLL_CTL_MOD, ch->fd, &epev) == -1) {
+ event_warn("Epoll ADD(%d) on %d retried as MOD; that failed too",
+ (int)epev.events, ch->fd);
+ return -1;
+ } else {
+ event_debug(("Epoll ADD(%d) on %d retried as MOD; succeeded.",
+ (int)epev.events,
+ ch->fd));
+ return 0;
}
- return -1;
+ }
+ break;
+ case EPOLL_CTL_DEL:
+ if (errno == ENOENT || errno == EBADF || errno == EPERM) {
+ /* If a delete fails with one of these errors,
+ * that's fine too: we closed the fd before we
+ * got around to calling epoll_dispatch. */
+ event_debug(("Epoll DEL(%d) on fd %d gave %s: DEL was unnecessary.",
+ (int)epev.events,
+ ch->fd,
+ strerror(errno)));
+ return 0;
+ }
+ break;
+ default:
+ break;
}
+
+ event_warn("Epoll %s(%d) on fd %d failed. Old events were %d; read change was %d (%s); write change was %d (%s)",
+ epoll_op_to_string(op),
+ (int)epev.events,
+ ch->fd,
+ ch->old_events,
+ ch->read_change,
+ change_to_string(ch->read_change),
+ ch->write_change,
+ change_to_string(ch->write_change));
+
+ return -1;
}
static int
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