mirror of
https://gitlab.nic.cz/labs/bird.git
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103 lines
2.2 KiB
C
103 lines
2.2 KiB
C
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/*
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* BIRD Coroutines
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*
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* (c) 2017 Martin Mares <mj@ucw.cz>
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* (c) 2020 Maria Matejka <mq@jmq.cz>
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*
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* Can be freely distributed and used under the terms of the GNU GPL.
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*/
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#ifndef _GNU_SOURCE
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#define _GNU_SOURCE
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#endif
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#undef LOCAL_DEBUG
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#undef DEBUG_LOCKING
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#include "lib/birdlib.h"
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#include "lib/locking.h"
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#include "lib/resource.h"
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/*
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* Implementation of coroutines based on POSIX threads
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*/
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#include <errno.h>
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#include <fcntl.h>
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#include <poll.h>
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#include <pthread.h>
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#include <semaphore.h>
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#include <stdatomic.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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/*
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* Locking subsystem
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*/
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#define ASSERT_NO_LOCK ASSERT_DIE(last_locked == NULL)
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struct domain_generic {
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pthread_mutex_t mutex;
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struct domain_generic **prev;
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struct lock_order *locked_by;
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const char *name;
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};
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#define DOMAIN_INIT(_name) { .mutex = PTHREAD_MUTEX_INITIALIZER, .name = _name }
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static struct domain_generic the_bird_domain_gen = DOMAIN_INIT("The BIRD");
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DOMAIN(the_bird) the_bird_domain = { .the_bird = &the_bird_domain_gen };
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struct domain_generic *
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domain_new(const char *name)
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{
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struct domain_generic *dg = xmalloc(sizeof(struct domain_generic));
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*dg = (struct domain_generic) DOMAIN_INIT(name);
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return dg;
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}
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void
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domain_free(struct domain_generic *dg)
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{
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pthread_mutex_destroy(&dg->mutex);
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xfree(dg);
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}
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_Thread_local struct lock_order locking_stack = {};
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_Thread_local struct domain_generic **last_locked = NULL;
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void do_lock(struct domain_generic *dg, struct domain_generic **lsp)
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{
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if (lsp <= last_locked)
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bug("Trying to lock in a bad order");
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if (*lsp)
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bug("Inconsistent locking stack state on lock");
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pthread_mutex_lock(&dg->mutex);
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if (dg->prev || dg->locked_by)
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bug("Previous unlock not finished correctly");
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dg->prev = last_locked;
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*lsp = dg;
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last_locked = lsp;
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dg->locked_by = &locking_stack;
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}
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void do_unlock(struct domain_generic *dg, struct domain_generic **lsp)
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{
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if (dg->locked_by != &locking_stack)
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bug("Inconsistent domain state on unlock");
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if ((last_locked != lsp) || (*lsp != dg))
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bug("Inconsistent locking stack state on unlock");
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dg->locked_by = NULL;
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last_locked = dg->prev;
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*lsp = NULL;
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dg->prev = NULL;
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pthread_mutex_unlock(&dg->mutex);
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}
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