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/* $OpenBSD: cmd-wait-for.c,v 1.12 2015/12/13 21:53:57 nicm Exp $ */
/*
* Copyright (c) 2013 Nicholas Marriott <nicm@users.sourceforge.net>
* Copyright (c) 2013 Thiago de Arruda <tpadilha84@gmail.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
* IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <stdlib.h>
#include <string.h>
#include "tmux.h"
/*
* Block or wake a client on a named wait channel.
*/
enum cmd_retval cmd_wait_for_exec(struct cmd *, struct cmd_q *);
const struct cmd_entry cmd_wait_for_entry = {
.name = "wait-for",
.alias = "wait",
.args = { "LSU", 1, 1 },
.usage = "[-L|-S|-U] channel",
.flags = 0,
.exec = cmd_wait_for_exec
};
struct wait_channel {
const char *name;
int locked;
int woken;
TAILQ_HEAD(, cmd_q) waiters;
TAILQ_HEAD(, cmd_q) lockers;
RB_ENTRY(wait_channel) entry;
};
RB_HEAD(wait_channels, wait_channel);
struct wait_channels wait_channels = RB_INITIALIZER(wait_channels);
int wait_channel_cmp(struct wait_channel *, struct wait_channel *);
RB_PROTOTYPE(wait_channels, wait_channel, entry, wait_channel_cmp);
RB_GENERATE(wait_channels, wait_channel, entry, wait_channel_cmp);
int
wait_channel_cmp(struct wait_channel *wc1, struct wait_channel *wc2)
{
return (strcmp(wc1->name, wc2->name));
}
enum cmd_retval cmd_wait_for_signal(struct cmd_q *, const char *,
struct wait_channel *);
enum cmd_retval cmd_wait_for_wait(struct cmd_q *, const char *,
struct wait_channel *);
enum cmd_retval cmd_wait_for_lock(struct cmd_q *, const char *,
struct wait_channel *);
enum cmd_retval cmd_wait_for_unlock(struct cmd_q *, const char *,
struct wait_channel *);
struct wait_channel *cmd_wait_for_add(const char *);
void cmd_wait_for_remove(struct wait_channel *wc);
struct wait_channel *
cmd_wait_for_add(const char *name)
{
struct wait_channel *wc;
wc = xmalloc(sizeof *wc);
wc->name = xstrdup(name);
wc->locked = 0;
wc->woken = 0;
TAILQ_INIT(&wc->waiters);
TAILQ_INIT(&wc->lockers);
RB_INSERT(wait_channels, &wait_channels, wc);
log_debug("add wait channel %s", wc->name);
return (wc);
}
void
cmd_wait_for_remove(struct wait_channel *wc)
{
if (wc->locked)
return;
if (!TAILQ_EMPTY(&wc->waiters) || !wc->woken)
return;
log_debug("remove wait channel %s", wc->name);
RB_REMOVE(wait_channels, &wait_channels, wc);
free((void *)wc->name);
free(wc);
}
enum cmd_retval
cmd_wait_for_exec(struct cmd *self, struct cmd_q *cmdq)
{
struct args *args = self->args;
const char *name = args->argv[0];
struct wait_channel *wc, wc0;
wc0.name = name;
wc = RB_FIND(wait_channels, &wait_channels, &wc0);
if (args_has(args, 'S'))
return (cmd_wait_for_signal(cmdq, name, wc));
if (args_has(args, 'L'))
return (cmd_wait_for_lock(cmdq, name, wc));
if (args_has(args, 'U'))
return (cmd_wait_for_unlock(cmdq, name, wc));
return (cmd_wait_for_wait(cmdq, name, wc));
}
enum cmd_retval
cmd_wait_for_signal(__unused struct cmd_q *cmdq, const char *name,
struct wait_channel *wc)
{
struct cmd_q *wq, *wq1;
if (wc == NULL)
wc = cmd_wait_for_add(name);
if (TAILQ_EMPTY(&wc->waiters) && !wc->woken) {
log_debug("signal wait channel %s, no waiters", wc->name);
wc->woken = 1;
return (CMD_RETURN_NORMAL);
}
log_debug("signal wait channel %s, with waiters", wc->name);
TAILQ_FOREACH_SAFE(wq, &wc->waiters, waitentry, wq1) {
TAILQ_REMOVE(&wc->waiters, wq, waitentry);
if (!cmdq_free(wq))
cmdq_continue(wq);
}
cmd_wait_for_remove(wc);
return (CMD_RETURN_NORMAL);
}
enum cmd_retval
cmd_wait_for_wait(struct cmd_q *cmdq, const char *name,
struct wait_channel *wc)
{
struct client *c = cmdq->client;
if (c == NULL || c->session != NULL) {
cmdq_error(cmdq, "not able to wait");
return (CMD_RETURN_ERROR);
}
if (wc == NULL)
wc = cmd_wait_for_add(name);
if (wc->woken) {
log_debug("wait channel %s already woken (%p)", wc->name, c);
cmd_wait_for_remove(wc);
return (CMD_RETURN_NORMAL);
}
log_debug("wait channel %s not woken (%p)", wc->name, c);
TAILQ_INSERT_TAIL(&wc->waiters, cmdq, waitentry);
cmdq->references++;
return (CMD_RETURN_WAIT);
}
enum cmd_retval
cmd_wait_for_lock(struct cmd_q *cmdq, const char *name,
struct wait_channel *wc)
{
if (cmdq->client == NULL || cmdq->client->session != NULL) {
cmdq_error(cmdq, "not able to lock");
return (CMD_RETURN_ERROR);
}
if (wc == NULL)
wc = cmd_wait_for_add(name);
if (wc->locked) {
TAILQ_INSERT_TAIL(&wc->lockers, cmdq, waitentry);
cmdq->references++;
return (CMD_RETURN_WAIT);
}
wc->locked = 1;
return (CMD_RETURN_NORMAL);
}
enum cmd_retval
cmd_wait_for_unlock(struct cmd_q *cmdq, const char *name,
struct wait_channel *wc)
{
struct cmd_q *wq;
if (wc == NULL || !wc->locked) {
cmdq_error(cmdq, "channel %s not locked", name);
return (CMD_RETURN_ERROR);
}
if ((wq = TAILQ_FIRST(&wc->lockers)) != NULL) {
TAILQ_REMOVE(&wc->lockers, wq, waitentry);
if (!cmdq_free(wq))
cmdq_continue(wq);
} else {
wc->locked = 0;
cmd_wait_for_remove(wc);
}
return (CMD_RETURN_NORMAL);
}
void
cmd_wait_for_flush(void)
{
struct wait_channel *wc, *wc1;
struct cmd_q *wq, *wq1;
RB_FOREACH_SAFE(wc, wait_channels, &wait_channels, wc1) {
TAILQ_FOREACH_SAFE(wq, &wc->waiters, waitentry, wq1) {
TAILQ_REMOVE(&wc->waiters, wq, waitentry);
if (!cmdq_free(wq))
cmdq_continue(wq);
}
wc->woken = 1;
TAILQ_FOREACH_SAFE(wq, &wc->lockers, waitentry, wq1) {
TAILQ_REMOVE(&wc->lockers, wq, waitentry);
if (!cmdq_free(wq))
cmdq_continue(wq);
}
wc->locked = 0;
cmd_wait_for_remove(wc);
}
}
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