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haproxy/include/proto/fd.h

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/*
* include/proto/fd.h
* File descriptors states.
*
* Copyright (C) 2000-2014 Willy Tarreau - w@1wt.eu
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation, version 2.1
* exclusively.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef _PROTO_FD_H
#define _PROTO_FD_H
#include <stdio.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include <common/config.h>
#include <types/fd.h>
/* public variables */
extern volatile struct fdlist fd_cache;
extern volatile struct fdlist fd_cache_local[MAX_THREADS];
extern volatile struct fdlist update_list;
extern unsigned long *polled_mask;
extern unsigned long fd_cache_mask; // Mask of threads with events in the cache
extern THREAD_LOCAL int *fd_updt; // FD updates list
extern THREAD_LOCAL int fd_nbupdt; // number of updates in the list
extern int poller_wr_pipe[MAX_THREADS];
__decl_hathreads(extern HA_RWLOCK_T __attribute__((aligned(64))) fdcache_lock); /* global lock to protect fd_cache array */
/* Deletes an FD from the fdsets.
* The file descriptor is also closed.
*/
void fd_delete(int fd);
/* Deletes an FD from the fdsets.
* The file descriptor is kept open.
*/
void fd_remove(int fd);
/* disable the specified poller */
void disable_poller(const char *poller_name);
void poller_pipe_io_handler(int fd);
/*
* Initialize the pollers till the best one is found.
* If none works, returns 0, otherwise 1.
* The pollers register themselves just before main() is called.
*/
int init_pollers();
/*
* Deinitialize the pollers.
*/
void deinit_pollers();
/*
* Some pollers may lose their connection after a fork(). It may be necessary
* to create initialize part of them again. Returns 0 in case of failure,
* otherwise 1. The fork() function may be NULL if unused. In case of error,
* the the current poller is destroyed and the caller is responsible for trying
* another one by calling init_pollers() again.
*/
int fork_poller();
/*
* Lists the known pollers on <out>.
* Should be performed only before initialization.
*/
int list_pollers(FILE *out);
/*
* Runs the polling loop
*/
void run_poller();
/* Scan and process the cached events. This should be called right after
* the poller.
*/
void fd_process_cached_events();
void fd_add_to_fd_list(volatile struct fdlist *list, int fd, int off);
void fd_rm_from_fd_list(volatile struct fdlist *list, int fd, int off);
/* Mark fd <fd> as updated for polling and allocate an entry in the update list
* for this if it was not already there. This can be done at any time.
*/
static inline void updt_fd_polling(const int fd)
{
if ((fdtab[fd].thread_mask & all_threads_mask) == tid_bit) {
unsigned int oldupdt;
/* note: we don't have a test-and-set yet in hathreads */
if (HA_ATOMIC_BTS(&fdtab[fd].update_mask, tid))
return;
oldupdt = HA_ATOMIC_ADD(&fd_nbupdt, 1) - 1;
fd_updt[oldupdt] = fd;
} else {
unsigned long update_mask = fdtab[fd].update_mask;
do {
if (update_mask == fdtab[fd].thread_mask)
return;
} while (!HA_ATOMIC_CAS(&fdtab[fd].update_mask, &update_mask,
fdtab[fd].thread_mask));
fd_add_to_fd_list(&update_list, fd, offsetof(struct fdtab, update));
}
}
/* Called from the poller to acknoledge we read an entry from the global
* update list, to remove our bit from the update_mask, and remove it from
* the list if we were the last one.
*/
static inline void done_update_polling(int fd)
{
unsigned long update_mask;
update_mask = HA_ATOMIC_AND(&fdtab[fd].update_mask, ~tid_bit);
while ((update_mask & all_threads_mask)== 0) {
/* If we were the last one that had to update that entry, remove it from the list */
fd_rm_from_fd_list(&update_list, fd, offsetof(struct fdtab, update));
if (update_list.first == fd)
abort();
update_mask = (volatile unsigned long)fdtab[fd].update_mask;
if ((update_mask & all_threads_mask) != 0) {
/* Maybe it's been re-updated in the meanwhile, and we
* wrongly removed it from the list, if so, re-add it
*/
fd_add_to_fd_list(&update_list, fd, offsetof(struct fdtab, update));
update_mask = (volatile unsigned long)(fdtab[fd].update_mask);
/* And then check again, just in case after all it
* should be removed, even if it's very unlikely, given
* the current thread wouldn't have been able to take
* care of it yet */
} else
break;
}
}
/* Allocates a cache entry for a file descriptor if it does not yet have one.
* This can be done at any time.
*/
static inline void fd_alloc_cache_entry(const int fd)
{
HA_ATOMIC_OR(&fd_cache_mask, fdtab[fd].thread_mask);
if (!(fdtab[fd].thread_mask & (fdtab[fd].thread_mask - 1)))
fd_add_to_fd_list(&fd_cache_local[my_ffsl(fdtab[fd].thread_mask) - 1], fd, offsetof(struct fdtab, cache));
else
fd_add_to_fd_list(&fd_cache, fd, offsetof(struct fdtab, cache));
}
/* Removes entry used by fd <fd> from the FD cache and replaces it with the
* last one.
* If the fd has no entry assigned, return immediately.
*/
static inline void fd_release_cache_entry(const int fd)
{
if (!(fdtab[fd].thread_mask & (fdtab[fd].thread_mask - 1)))
fd_rm_from_fd_list(&fd_cache_local[my_ffsl(fdtab[fd].thread_mask) - 1], fd, offsetof(struct fdtab, cache));
else
fd_rm_from_fd_list(&fd_cache, fd, offsetof(struct fdtab, cache));
}
/* This function automatically enables/disables caching for an entry depending
* on its state. It is only called on state changes.
*/
static inline void fd_update_cache(int fd)
{
/* only READY and ACTIVE states (the two with both flags set) require a cache entry */
if (((fdtab[fd].state & (FD_EV_READY_R | FD_EV_ACTIVE_R)) == (FD_EV_READY_R | FD_EV_ACTIVE_R)) ||
((fdtab[fd].state & (FD_EV_READY_W | FD_EV_ACTIVE_W)) == (FD_EV_READY_W | FD_EV_ACTIVE_W))) {
fd_alloc_cache_entry(fd);
}
else {
fd_release_cache_entry(fd);
}
}
/*
* returns the FD's recv state (FD_EV_*)
*/
static inline int fd_recv_state(const int fd)
{
return ((unsigned)fdtab[fd].state >> (4 * DIR_RD)) & FD_EV_STATUS;
}
/*
* returns true if the FD is active for recv
*/
static inline int fd_recv_active(const int fd)
{
return (unsigned)fdtab[fd].state & FD_EV_ACTIVE_R;
}
/*
* returns true if the FD is ready for recv
*/
static inline int fd_recv_ready(const int fd)
{
return (unsigned)fdtab[fd].state & FD_EV_READY_R;
}
/*
* returns true if the FD is polled for recv
*/
static inline int fd_recv_polled(const int fd)
{
return (unsigned)fdtab[fd].state & FD_EV_POLLED_R;
}
/*
* returns the FD's send state (FD_EV_*)
*/
static inline int fd_send_state(const int fd)
{
return ((unsigned)fdtab[fd].state >> (4 * DIR_WR)) & FD_EV_STATUS;
}
/*
* returns true if the FD is active for send
*/
static inline int fd_send_active(const int fd)
{
return (unsigned)fdtab[fd].state & FD_EV_ACTIVE_W;
}
/*
* returns true if the FD is ready for send
*/
static inline int fd_send_ready(const int fd)
{
return (unsigned)fdtab[fd].state & FD_EV_READY_W;
}
/*
* returns true if the FD is polled for send
*/
static inline int fd_send_polled(const int fd)
{
return (unsigned)fdtab[fd].state & FD_EV_POLLED_W;
}
/*
* returns true if the FD is active for recv or send
*/
static inline int fd_active(const int fd)
{
return (unsigned)fdtab[fd].state & FD_EV_ACTIVE_RW;
}
/* Disable processing recv events on fd <fd> */
static inline void fd_stop_recv(int fd)
{
unsigned char old, new;
old = fdtab[fd].state;
do {
if (!(old & FD_EV_ACTIVE_R))
return;
new = old & ~FD_EV_ACTIVE_R;
new &= ~FD_EV_POLLED_R;
} while (unlikely(!HA_ATOMIC_CAS(&fdtab[fd].state, &old, new)));
if ((old ^ new) & FD_EV_POLLED_R)
updt_fd_polling(fd);
HA_SPIN_LOCK(FD_LOCK, &fdtab[fd].lock);
fd_update_cache(fd); /* need an update entry to change the state */
HA_SPIN_UNLOCK(FD_LOCK, &fdtab[fd].lock);
}
/* Disable processing send events on fd <fd> */
static inline void fd_stop_send(int fd)
{
unsigned char old, new;
old = fdtab[fd].state;
do {
if (!(old & FD_EV_ACTIVE_W))
return;
new = old & ~FD_EV_ACTIVE_W;
new &= ~FD_EV_POLLED_W;
} while (unlikely(!HA_ATOMIC_CAS(&fdtab[fd].state, &old, new)));
if ((old ^ new) & FD_EV_POLLED_W)
updt_fd_polling(fd);
HA_SPIN_LOCK(FD_LOCK, &fdtab[fd].lock);
fd_update_cache(fd); /* need an update entry to change the state */
HA_SPIN_UNLOCK(FD_LOCK, &fdtab[fd].lock);
}
/* Disable processing of events on fd <fd> for both directions. */
static inline void fd_stop_both(int fd)
{
unsigned char old, new;
old = fdtab[fd].state;
do {
if (!(old & FD_EV_ACTIVE_RW))
return;
new = old & ~FD_EV_ACTIVE_RW;
new &= ~FD_EV_POLLED_RW;
} while (unlikely(!HA_ATOMIC_CAS(&fdtab[fd].state, &old, new)));
if ((old ^ new) & FD_EV_POLLED_RW)
updt_fd_polling(fd);
HA_SPIN_LOCK(FD_LOCK, &fdtab[fd].lock);
fd_update_cache(fd); /* need an update entry to change the state */
HA_SPIN_UNLOCK(FD_LOCK, &fdtab[fd].lock);
}
/* Report that FD <fd> cannot receive anymore without polling (EAGAIN detected). */
static inline void fd_cant_recv(const int fd)
{
unsigned char old, new;
old = fdtab[fd].state;
do {
if (!(old & FD_EV_READY_R))
return;
new = old & ~FD_EV_READY_R;
if (new & FD_EV_ACTIVE_R)
new |= FD_EV_POLLED_R;
} while (unlikely(!HA_ATOMIC_CAS(&fdtab[fd].state, &old, new)));
if ((old ^ new) & FD_EV_POLLED_R)
updt_fd_polling(fd);
HA_SPIN_LOCK(FD_LOCK, &fdtab[fd].lock);
fd_update_cache(fd); /* need an update entry to change the state */
HA_SPIN_UNLOCK(FD_LOCK, &fdtab[fd].lock);
}
/* Report that FD <fd> can receive anymore without polling. */
static inline void fd_may_recv(const int fd)
{
/* marking ready never changes polled status */
HA_ATOMIC_OR(&fdtab[fd].state, FD_EV_READY_R);
HA_SPIN_LOCK(FD_LOCK, &fdtab[fd].lock);
fd_update_cache(fd); /* need an update entry to change the state */
HA_SPIN_UNLOCK(FD_LOCK, &fdtab[fd].lock);
}
/* Disable readiness when polled. This is useful to interrupt reading when it
* is suspected that the end of data might have been reached (eg: short read).
* This can only be done using level-triggered pollers, so if any edge-triggered
* is ever implemented, a test will have to be added here.
*/
static inline void fd_done_recv(const int fd)
{
unsigned char old, new;
old = fdtab[fd].state;
do {
if ((old & (FD_EV_POLLED_R|FD_EV_READY_R)) != (FD_EV_POLLED_R|FD_EV_READY_R))
return;
new = old & ~FD_EV_READY_R;
if (new & FD_EV_ACTIVE_R)
new |= FD_EV_POLLED_R;
} while (unlikely(!HA_ATOMIC_CAS(&fdtab[fd].state, &old, new)));
if ((old ^ new) & FD_EV_POLLED_R)
updt_fd_polling(fd);
HA_SPIN_LOCK(FD_LOCK, &fdtab[fd].lock);
fd_update_cache(fd); /* need an update entry to change the state */
HA_SPIN_UNLOCK(FD_LOCK, &fdtab[fd].lock);
}
/* Report that FD <fd> cannot send anymore without polling (EAGAIN detected). */
static inline void fd_cant_send(const int fd)
{
unsigned char old, new;
old = fdtab[fd].state;
do {
if (!(old & FD_EV_READY_W))
return;
new = old & ~FD_EV_READY_W;
if (new & FD_EV_ACTIVE_W)
new |= FD_EV_POLLED_W;
} while (unlikely(!HA_ATOMIC_CAS(&fdtab[fd].state, &old, new)));
if ((old ^ new) & FD_EV_POLLED_W)
updt_fd_polling(fd);
HA_SPIN_LOCK(FD_LOCK, &fdtab[fd].lock);
fd_update_cache(fd); /* need an update entry to change the state */
HA_SPIN_UNLOCK(FD_LOCK, &fdtab[fd].lock);
}
/* Report that FD <fd> can send anymore without polling (EAGAIN detected). */
static inline void fd_may_send(const int fd)
{
/* marking ready never changes polled status */
HA_ATOMIC_OR(&fdtab[fd].state, FD_EV_READY_W);
HA_SPIN_LOCK(FD_LOCK, &fdtab[fd].lock);
fd_update_cache(fd); /* need an update entry to change the state */
HA_SPIN_UNLOCK(FD_LOCK, &fdtab[fd].lock);
}
/* Prepare FD <fd> to try to receive */
static inline void fd_want_recv(int fd)
{
unsigned char old, new;
old = fdtab[fd].state;
do {
if (old & FD_EV_ACTIVE_R)
return;
new = old | FD_EV_ACTIVE_R;
if (!(new & FD_EV_READY_R))
new |= FD_EV_POLLED_R;
} while (unlikely(!HA_ATOMIC_CAS(&fdtab[fd].state, &old, new)));
if ((old ^ new) & FD_EV_POLLED_R)
updt_fd_polling(fd);
HA_SPIN_LOCK(FD_LOCK, &fdtab[fd].lock);
fd_update_cache(fd); /* need an update entry to change the state */
HA_SPIN_UNLOCK(FD_LOCK, &fdtab[fd].lock);
}
/* Prepare FD <fd> to try to send */
static inline void fd_want_send(int fd)
{
unsigned char old, new;
old = fdtab[fd].state;
do {
if (old & FD_EV_ACTIVE_W)
return;
new = old | FD_EV_ACTIVE_W;
if (!(new & FD_EV_READY_W))
new |= FD_EV_POLLED_W;
} while (unlikely(!HA_ATOMIC_CAS(&fdtab[fd].state, &old, new)));
if ((old ^ new) & FD_EV_POLLED_W)
updt_fd_polling(fd);
HA_SPIN_LOCK(FD_LOCK, &fdtab[fd].lock);
fd_update_cache(fd); /* need an update entry to change the state */
HA_SPIN_UNLOCK(FD_LOCK, &fdtab[fd].lock);
}
/* Update events seen for FD <fd> and its state if needed. This should be called
* by the poller to set FD_POLL_* flags. */
static inline void fd_update_events(int fd, int evts)
{
HA_SPIN_LOCK(FD_LOCK, &fdtab[fd].lock);
fdtab[fd].ev &= FD_POLL_STICKY;
fdtab[fd].ev |= evts;
HA_SPIN_UNLOCK(FD_LOCK, &fdtab[fd].lock);
if (fdtab[fd].ev & (FD_POLL_IN | FD_POLL_HUP | FD_POLL_ERR))
fd_may_recv(fd);
if (fdtab[fd].ev & (FD_POLL_OUT | FD_POLL_ERR))
fd_may_send(fd);
}
/* Prepares <fd> for being polled */
static inline void fd_insert(int fd, void *owner, void (*iocb)(int fd), unsigned long thread_mask)
{
HA_SPIN_LOCK(FD_LOCK, &fdtab[fd].lock);
fdtab[fd].owner = owner;
fdtab[fd].iocb = iocb;
fdtab[fd].ev = 0;
fdtab[fd].linger_risk = 0;
fdtab[fd].cloned = 0;
fdtab[fd].thread_mask = thread_mask;
/* note: do not reset polled_mask here as it indicates which poller
* still knows this FD from a possible previous round.
*/
HA_SPIN_UNLOCK(FD_LOCK, &fdtab[fd].lock);
}
/* These are replacements for FD_SET, FD_CLR, FD_ISSET, working on uints */
static inline void hap_fd_set(int fd, unsigned int *evts)
{
HA_ATOMIC_OR(&evts[fd / (8*sizeof(*evts))], 1U << (fd & (8*sizeof(*evts) - 1)));
}
static inline void hap_fd_clr(int fd, unsigned int *evts)
{
HA_ATOMIC_AND(&evts[fd / (8*sizeof(*evts))], ~(1U << (fd & (8*sizeof(*evts) - 1))));
}
static inline unsigned int hap_fd_isset(int fd, unsigned int *evts)
{
return evts[fd / (8*sizeof(*evts))] & (1U << (fd & (8*sizeof(*evts) - 1)));
}
static inline void wake_thread(int tid)
{
char c = 'c';
shut_your_big_mouth_gcc(write(poller_wr_pipe[tid], &c, 1));
}
#endif /* _PROTO_FD_H */
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/
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