/* $OpenBSD: cmd-wait-for.c,v 1.22 2021/08/21 10:22:39 nicm Exp $ */ /* * Copyright (c) 2013 Nicholas Marriott * Copyright (c) 2013 Thiago de Arruda * * 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 #include #include #include "tmux.h" /* * Block or wake a client on a named wait channel. */ static enum cmd_retval cmd_wait_for_exec(struct cmd *, struct cmdq_item *); const struct cmd_entry cmd_wait_for_entry = { .name = "wait-for", .alias = "wait", .args = { "LSU", 1, 1, NULL }, .usage = "[-L|-S|-U] channel", .flags = 0, .exec = cmd_wait_for_exec }; struct wait_item { struct cmdq_item *item; TAILQ_ENTRY(wait_item) entry; }; struct wait_channel { const char *name; int locked; int woken; TAILQ_HEAD(, wait_item) waiters; TAILQ_HEAD(, wait_item) lockers; RB_ENTRY(wait_channel) entry; }; RB_HEAD(wait_channels, wait_channel); static struct wait_channels wait_channels = RB_INITIALIZER(wait_channels); static int wait_channel_cmp(struct wait_channel *, struct wait_channel *); RB_GENERATE_STATIC(wait_channels, wait_channel, entry, wait_channel_cmp); static int wait_channel_cmp(struct wait_channel *wc1, struct wait_channel *wc2) { return (strcmp(wc1->name, wc2->name)); } static enum cmd_retval cmd_wait_for_signal(struct cmdq_item *, const char *, struct wait_channel *); static enum cmd_retval cmd_wait_for_wait(struct cmdq_item *, const char *, struct wait_channel *); static enum cmd_retval cmd_wait_for_lock(struct cmdq_item *, const char *, struct wait_channel *); static enum cmd_retval cmd_wait_for_unlock(struct cmdq_item *, const char *, struct wait_channel *); static struct wait_channel *cmd_wait_for_add(const char *); static void cmd_wait_for_remove(struct wait_channel *); static 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); } static 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); } static enum cmd_retval cmd_wait_for_exec(struct cmd *self, struct cmdq_item *item) { struct args *args = cmd_get_args(self); const char *name = args_string(args, 0); struct wait_channel *wc, find; find.name = name; wc = RB_FIND(wait_channels, &wait_channels, &find); if (args_has(args, 'S')) return (cmd_wait_for_signal(item, name, wc)); if (args_has(args, 'L')) return (cmd_wait_for_lock(item, name, wc)); if (args_has(args, 'U')) return (cmd_wait_for_unlock(item, name, wc)); return (cmd_wait_for_wait(item, name, wc)); } static enum cmd_retval cmd_wait_for_signal(__unused struct cmdq_item *item, const char *name, struct wait_channel *wc) { struct wait_item *wi, *wi1; 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(wi, &wc->waiters, entry, wi1) { cmdq_continue(wi->item); TAILQ_REMOVE(&wc->waiters, wi, entry); free(wi); } cmd_wait_for_remove(wc); return (CMD_RETURN_NORMAL); } static enum cmd_retval cmd_wait_for_wait(struct cmdq_item *item, const char *name, struct wait_channel *wc) { struct client *c = cmdq_get_client(item); struct wait_item *wi; if (c == NULL) { cmdq_error(item, "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); wi = xcalloc(1, sizeof *wi); wi->item = item; TAILQ_INSERT_TAIL(&wc->waiters, wi, entry); return (CMD_RETURN_WAIT); } static enum cmd_retval cmd_wait_for_lock(struct cmdq_item *item, const char *name, struct wait_channel *wc) { struct wait_item *wi; if (cmdq_get_client(item) == NULL) { cmdq_error(item, "not able to lock"); return (CMD_RETURN_ERROR); } if (wc == NULL) wc = cmd_wait_for_add(name); if (wc->locked) { wi = xcalloc(1, sizeof *wi); wi->item = item; TAILQ_INSERT_TAIL(&wc->lockers, wi, entry); return (CMD_RETURN_WAIT); } wc->locked = 1; return (CMD_RETURN_NORMAL); } static enum cmd_retval cmd_wait_for_unlock(struct cmdq_item *item, const char *name, struct wait_channel *wc) { struct wait_item *wi; if (wc == NULL || !wc->locked) { cmdq_error(item, "channel %s not locked", name); return (CMD_RETURN_ERROR); } if ((wi = TAILQ_FIRST(&wc->lockers)) != NULL) { cmdq_continue(wi->item); TAILQ_REMOVE(&wc->lockers, wi, entry); free(wi); } 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 wait_item *wi, *wi1; RB_FOREACH_SAFE(wc, wait_channels, &wait_channels, wc1) { TAILQ_FOREACH_SAFE(wi, &wc->waiters, entry, wi1) { cmdq_continue(wi->item); TAILQ_REMOVE(&wc->waiters, wi, entry); free(wi); } wc->woken = 1; TAILQ_FOREACH_SAFE(wi, &wc->lockers, entry, wi1) { cmdq_continue(wi->item); TAILQ_REMOVE(&wc->lockers, wi, entry); free(wi); } wc->locked = 0; cmd_wait_for_remove(wc); } }