serval-dna/fdqueue.c
Andrew Bettison 291a631095 New header file "fdqueue.h"
So that "http_server.h" does not have to include "serval.h" which
creates a circular dependency.

Remove the __SERVALDNA__HTTP_SERVER_IMPLEMENTATION hack from
"http_server.h"
2013-10-25 00:20:53 +10:30

348 lines
10 KiB
C

/*
Serval Distributed Numbering Architecture (DNA)
Copyright (C) 2012 Paul Gardner-Stephen
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; either version 2
of the License, or (at your option) any later version.
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include "fdqueue.h"
#include "conf.h"
#include "str.h"
#include "strbuf.h"
#include "strbuf_helpers.h"
#define MAX_WATCHED_FDS 128
struct pollfd fds[MAX_WATCHED_FDS];
int fdcount=0;
struct sched_ent *fd_callbacks[MAX_WATCHED_FDS];
struct sched_ent *next_alarm=NULL;
struct sched_ent *next_deadline=NULL;
struct profile_total poll_stats={NULL,0,"Idle (in poll)",0,0,0};
#define alloca_alarm_name(alarm) ((alarm)->stats ? alloca_str_toprint((alarm)->stats->name) : "Unnamed")
void list_alarms()
{
DEBUG("Alarms;");
time_ms_t now = gettime_ms();
struct sched_ent *alarm;
for (alarm = next_deadline; alarm; alarm = alarm->_next)
DEBUGF("%p %s deadline in %"PRId64"ms", alarm->function, alloca_alarm_name(alarm), alarm->deadline - now);
for (alarm = next_alarm; alarm; alarm = alarm->_next)
DEBUGF("%p %s in %"PRId64"ms, deadline in %"PRId64"ms", alarm->function, alloca_alarm_name(alarm), alarm->alarm - now, alarm->deadline - now);
DEBUG("File handles;");
int i;
for (i = 0; i < fdcount; ++i)
DEBUGF("%s watching #%d", alloca_alarm_name(fd_callbacks[i]), fds[i].fd);
}
int deadline(struct sched_ent *alarm)
{
struct sched_ent *node = next_deadline, *last = NULL;
if (alarm->deadline < alarm->alarm)
alarm->deadline = alarm->alarm;
while(node!=NULL){
if (node->deadline > alarm->deadline)
break;
last = node;
node = node->_next;
}
if (last == NULL){
next_deadline = alarm;
}else{
last->_next = alarm;
}
alarm->_prev = last;
if(node!=NULL)
node->_prev = alarm;
alarm->_next = node;
return 0;
}
int is_scheduled(const struct sched_ent *alarm)
{
return alarm->_next || alarm->_prev || alarm == next_alarm || alarm == next_deadline;
}
// add an alarm to the list of scheduled function calls.
// simply populate .alarm with the absolute time, and .function with the method to call.
// on calling .poll.revents will be zero.
int _schedule(struct __sourceloc __whence, struct sched_ent *alarm)
{
if (config.debug.io)
DEBUGF("schedule(alarm=%s) called from %s() %s:%d",
alloca_alarm_name(alarm),
__whence.function,__whence.file,__whence.line);
if (!alarm->stats)
WARNF("schedule() called from %s() %s:%d without supplying an alarm name",
__whence.function,__whence.file,__whence.line);
struct sched_ent *node = next_alarm, *last = NULL;
if (is_scheduled(alarm))
FATAL("Scheduling an alarm that is already scheduled");
if (!alarm->function)
return WHY("Can't schedule if you haven't set the function pointer");
time_ms_t now = gettime_ms();
if (alarm->deadline < alarm->alarm)
alarm->deadline = alarm->alarm;
if (now - alarm->deadline > 1000){
// 1000ms ago? thats silly, if you keep doing it noone else will get a turn.
WHYF("Alarm %s tried to schedule a deadline %"PRId64"ms ago, from %s() %s:%d",
alloca_alarm_name(alarm),
(now - alarm->deadline),
__whence.function,__whence.file,__whence.line);
}
// if the alarm has already expired, move straight to the deadline queue
if (alarm->alarm <= now)
return deadline(alarm);
while(node!=NULL){
if (node->alarm > alarm->alarm)
break;
last = node;
node = node->_next;
}
if (last == NULL){
next_alarm = alarm;
}else{
last->_next=alarm;
}
alarm->_prev = last;
if(node!=NULL)
node->_prev = alarm;
alarm->_next = node;
return 0;
}
// remove a function from the schedule before it has fired
// safe to unschedule twice...
int _unschedule(struct __sourceloc __whence, struct sched_ent *alarm)
{
if (config.debug.io)
DEBUGF("unschedule(alarm=%s)", alloca_alarm_name(alarm));
struct sched_ent *prev = alarm->_prev;
struct sched_ent *next = alarm->_next;
if (prev)
prev->_next = next;
else if(next_alarm==alarm)
next_alarm = next;
else if(next_deadline==alarm)
next_deadline = next;
if (next)
next->_prev = prev;
alarm->_prev = NULL;
alarm->_next = NULL;
return 0;
}
// start watching a file handle, call this function again if you wish to change the event mask
int _watch(struct __sourceloc __whence, struct sched_ent *alarm)
{
if (config.debug.io)
DEBUGF("watch(alarm=%s)", alloca_alarm_name(alarm));
if (!alarm->stats)
WARNF("watch() called from %s() %s:%d without supplying an alarm name",
__whence.function,__whence.file,__whence.line);
if (!alarm->function)
return WHY("Can't watch if you haven't set the function pointer");
if (alarm->_poll_index>=0 && fd_callbacks[alarm->_poll_index]==alarm){
// updating event flags
if (config.debug.io)
DEBUGF("Updating watch %s, #%d for %d", alloca_alarm_name(alarm), alarm->poll.fd, alarm->poll.events);
}else{
if (config.debug.io)
DEBUGF("Adding watch %s, #%d for %d", alloca_alarm_name(alarm), alarm->poll.fd, alarm->poll.events);
if (fdcount>=MAX_WATCHED_FDS)
return WHY("Too many file handles to watch");
fd_callbacks[fdcount]=alarm;
alarm->poll.revents = 0;
alarm->_poll_index=fdcount;
fdcount++;
}
fds[alarm->_poll_index]=alarm->poll;
return 0;
}
// stop watching a file handle
int _unwatch(struct __sourceloc __whence, struct sched_ent *alarm)
{
if (config.debug.io)
DEBUGF("unwatch(alarm=%s)", alloca_alarm_name(alarm));
int index = alarm->_poll_index;
if (index <0 || fds[index].fd!=alarm->poll.fd)
return WHY("Attempted to unwatch a handle that is not being watched");
fdcount--;
if (index!=fdcount){
// squash fds
fds[index] = fds[fdcount];
fd_callbacks[index] = fd_callbacks[fdcount];
fd_callbacks[index]->_poll_index=index;
}
fds[fdcount].fd=-1;
fd_callbacks[fdcount]=NULL;
alarm->_poll_index=-1;
if (config.debug.io)
DEBUGF("%s stopped watching #%d for %d", alloca_alarm_name(alarm), alarm->poll.fd, alarm->poll.events);
return 0;
}
static void call_alarm(struct sched_ent *alarm, int revents)
{
IN();
if (!alarm)
FATAL("Attempted to call with no alarm");
struct call_stats call_stats;
call_stats.totals = alarm->stats;
if (config.debug.io) DEBUGF("Calling alarm/callback %p ('%s')",
alarm, alloca_alarm_name(alarm));
if (call_stats.totals)
fd_func_enter(__HERE__, &call_stats);
alarm->poll.revents = revents;
alarm->function(alarm);
if (call_stats.totals)
fd_func_exit(__HERE__, &call_stats);
if (config.debug.io) DEBUGF("Alarm %p returned",alarm);
OUT();
}
int fd_poll()
{
IN();
int i, r=0;
int ms=60000;
time_ms_t now = gettime_ms();
if (!next_alarm && !next_deadline && fdcount==0)
RETURN(0);
/* move alarms that have elapsed to the deadline queue */
while (next_alarm!=NULL&&next_alarm->alarm <=now){
struct sched_ent *alarm = next_alarm;
unschedule(alarm);
deadline(alarm);
}
/* work out how long we can block in poll */
if (next_deadline)
ms = 0;
else if (next_alarm){
ms = next_alarm->alarm - now;
}
/* Make sure we don't have any silly timeouts that will make us wait forever. */
if (ms<0) ms=0;
/* check if any file handles have activity */
{
struct call_stats call_stats;
call_stats.totals=&poll_stats;
fd_func_enter(__HERE__, &call_stats);
if (fdcount==0){
sleep_ms(ms);
}else{
r = poll(fds, fdcount, ms);
if (config.debug.io) {
strbuf b = strbuf_alloca(1024);
int i;
for (i = 0; i < fdcount; ++i) {
if (i)
strbuf_puts(b, ", ");
strbuf_sprintf(b, "%d:", fds[i].fd);
strbuf_append_poll_events(b, fds[i].events);
strbuf_puts(b, "->");
strbuf_append_poll_events(b, fds[i].revents);
}
DEBUGF("poll(fds=(%s), fdcount=%d, ms=%d) -> %d", strbuf_str(b), fdcount, ms, r);
}
}
fd_func_exit(__HERE__, &call_stats);
now=gettime_ms();
}
// Reading new data takes priority over everything else
// Are any handles marked with POLLIN?
int in_count=0;
if (r>0){
for (i=0;i<fdcount;i++)
if (fds[i].revents & POLLIN)
in_count++;
}
/* call one alarm function, but only if its deadline time has elapsed OR there is no incoming file activity */
if (next_deadline && (next_deadline->deadline <=now || (in_count==0))){
struct sched_ent *alarm = next_deadline;
unschedule(alarm);
call_alarm(alarm, 0);
now=gettime_ms();
// after running a timed alarm, unless we already know there is data to read we want to check for more incoming IO before we send more outgoing.
if (in_count==0)
RETURN(1);
}
/* If file descriptors are ready, then call the appropriate functions */
if (r>0) {
for(i=fdcount -1;i>=0;i--){
if (fds[i].revents) {
// if any handles have POLLIN set, don't process any other handles
if (!(fds[i].revents&POLLIN || in_count==0))
continue;
int fd = fds[i].fd;
/* Call the alarm callback with the socket in non-blocking mode */
errno=0;
set_nonblock(fd);
// Work around OSX behaviour that doesn't set POLLERR on
// devices that have been deconfigured, e.g., a USB serial adapter
// that has been removed.
if (errno == ENXIO) fds[i].revents|=POLLERR;
call_alarm(fd_callbacks[i], fds[i].revents);
/* The alarm may have closed and unwatched the descriptor, make sure this descriptor still matches */
if (i<fdcount && fds[i].fd == fd){
if (set_block(fds[i].fd))
FATALF("Alarm %p %s has a bad descriptor that wasn't closed!", fd_callbacks[i], alloca_alarm_name(fd_callbacks[i]));
}
}
}
}
RETURN(1);
OUT();
}