commit 35e3b69d60f337724163e9543b5728b907ce34dd
parent f1892c4dffa7df6995cd8c9ebd47e0ce7f0e457e
Author: Laslo Hunhold <dev@frign.de>
Date: Sun, 31 Jan 2021 11:33:46 +0100
Refactor queue-event-handling to be pointer-centric
This is one aspect where we can see that kqueue(2) is superior to
epoll(7). While kqueue(2) allows you to both store a pointer and read
out the fd of an event in the ready-list, epoll(7) only provides you
with one of the two (by only offering a union-type-field where you
either store an fd or a pointer).
Previously, wrapper functions would allow to extract either from any
event, which was only non-hacky in the OpenBSD-case, because nothing
stopped you from reading the "fd" from the union that actually was
assigned as a pointer. The distinction was there in the first place
because we are listening on the main incoming socket and other "client"-
sockets at the same time. The main-socket-events contained the socket-fd
and the client-sockets contained the connection-struct-pointer. Now, we
just set the data-pointer of the main socket to NULL to indicate it,
yielding a much more refined usage with one fewer way to screw things
up.
Signed-off-by: Laslo Hunhold <dev@frign.de>
Diffstat:
| M | main.c | | | 31 | +++++++++++++++---------------- |
| M | queue.c | | | 32 | +++++--------------------------- |
| M | queue.h | | | 3 | +-- |
3 files changed, 21 insertions(+), 45 deletions(-)
diff --git a/main.c b/main.c
@@ -210,9 +210,9 @@ static void *
thread_method(void *data)
{
queue_event *event = NULL;
- struct connection *connection, *c;
+ struct connection *connection, *c, *newc;
struct worker_data *d = (struct worker_data *)data;
- int qfd, fd;
+ int qfd;
ssize_t nready;
size_t i;
@@ -226,7 +226,7 @@ thread_method(void *data)
exit(1);
}
- /* add insock to the interest list */
+ /* add insock to the interest list (with data=NULL) */
if (queue_add_fd(qfd, d->insock, QUEUE_EVENT_IN, 1, NULL) < 0) {
exit(1);
}
@@ -244,12 +244,12 @@ thread_method(void *data)
/* handle events */
for (i = 0; i < (size_t)nready; i++) {
- if (queue_event_is_dropped(&event[i])) {
- fd = queue_event_get_fd(&event[i]);
+ c = queue_event_get_data(&event[i]);
- if (fd != d->insock) {
- memset(queue_event_get_ptr(&event[i]),
- 0, sizeof(struct connection));
+ if (queue_event_is_dropped(&event[i])) {
+ if (c != NULL) {
+ queue_rem_fd(qfd, c->fd);
+ close_connection(c);
}
printf("dropped a connection\n");
@@ -257,11 +257,11 @@ thread_method(void *data)
continue;
}
- if (queue_event_get_fd(&event[i]) == d->insock) {
+ if (c == NULL) {
/* add new connection to the interest list */
- if (!(c = accept_connection(d->insock,
- connection,
- d->nslots))) {
+ if (!(newc = accept_connection(d->insock,
+ connection,
+ d->nslots))) {
/*
* the socket is either blocking
* or something failed.
@@ -275,20 +275,19 @@ thread_method(void *data)
* (we want IN, because we start
* with receiving the header)
*/
- if (queue_add_fd(qfd, c->fd,
+ if (queue_add_fd(qfd, newc->fd,
QUEUE_EVENT_IN,
- 0, c) < 0) {
+ 0, newc) < 0) {
/* not much we can do here */
continue;
}
} else {
- c = queue_event_get_ptr(&event[i]);
-
/* serve existing connection */
serve_connection(c, d->srv);
if (c->fd == 0) {
/* we are done */
+ memset(c, 0, sizeof(struct connection));
continue;
}
diff --git a/queue.c b/queue.c
@@ -65,14 +65,8 @@ queue_add_fd(int qfd, int fd, enum queue_event_type t, int shared,
break;
}
- /* set data */
- if (data == NULL) {
- /* the data is the fd itself */
- e.data.fd = fd;
- } else {
- /* set data pointer */
- e.data.ptr = (void *)data;
- }
+ /* set data pointer */
+ e.data.ptr = (void *)data;
/* register fd in the interest list */
if (epoll_ctl(qfd, EPOLL_CTL_ADD, fd, &e) < 0) {
@@ -124,14 +118,8 @@ queue_mod_fd(int qfd, int fd, enum queue_event_type t, const void *data)
break;
}
- /* set data */
- if (data == NULL) {
- /* the data is the fd itself */
- e.data.fd = fd;
- } else {
- /* set data pointer */
- e.data.ptr = (void *)data;
- }
+ /* set data pointer */
+ e.data.ptr = (void *)data;
/* register fd in the interest list */
if (epoll_ctl(qfd, EPOLL_CTL_MOD, fd, &e) < 0) {
@@ -208,18 +196,8 @@ queue_wait(int qfd, queue_event *e, size_t elen)
return nready;
}
-int
-queue_event_get_fd(const queue_event *e)
-{
- #ifdef __linux__
- return e->data.fd;
- #else
- return e->ident;
- #endif
-}
-
void *
-queue_event_get_ptr(const queue_event *e)
+queue_event_get_data(const queue_event *e)
{
#ifdef __linux__
return e->data.ptr;
diff --git a/queue.h b/queue.h
@@ -26,8 +26,7 @@ int queue_mod_fd(int, int, enum queue_event_type, const void *);
int queue_rem_fd(int, int);
ssize_t queue_wait(int, queue_event *, size_t);
-int queue_event_get_fd(const queue_event *);
-void *queue_event_get_ptr(const queue_event *);
+void *queue_event_get_data(const queue_event *);
int queue_event_is_dropped(const queue_event *e);
