diff options
author | Maria Matejka <mq@ucw.cz> | 2022-10-04 15:40:52 +0200 |
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committer | Maria Matejka <mq@ucw.cz> | 2022-10-04 15:40:52 +0200 |
commit | becca314e2546d6005a23398ce2d3012d4b396cb (patch) | |
tree | bdd2f55e81d42e6a1108593840c9273106676e09 /sysdep/unix/domain.c | |
parent | 61c127c021ac34eba25d3245ccf8f9eb9dd352f5 (diff) | |
parent | 0072d11f3431165240656edf6ade473554b8747e (diff) |
Merge commit '0072d11f' into tmp-learn
Diffstat (limited to 'sysdep/unix/domain.c')
-rw-r--r-- | sysdep/unix/domain.c | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/sysdep/unix/domain.c b/sysdep/unix/domain.c new file mode 100644 index 00000000..0a5858a6 --- /dev/null +++ b/sysdep/unix/domain.c @@ -0,0 +1,116 @@ +/* + * BIRD Locking + * + * (c) 2020 Maria Matejka <mq@jmq.cz> + * + * Can be freely distributed and used under the terms of the GNU GPL. + */ + +#ifndef _GNU_SOURCE +#define _GNU_SOURCE +#endif + +#undef LOCAL_DEBUG + +#undef DEBUG_LOCKING + +#include "lib/birdlib.h" +#include "lib/locking.h" +#include "lib/resource.h" +#include "lib/timer.h" + +#include "conf/conf.h" + +#include <errno.h> +#include <fcntl.h> +#include <poll.h> +#include <pthread.h> +#include <semaphore.h> +#include <stdatomic.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +/* + * Locking subsystem + */ + +_Thread_local struct lock_order locking_stack = {}; +_Thread_local struct domain_generic **last_locked = NULL; + +#define ASSERT_NO_LOCK ASSERT_DIE(last_locked == NULL) + +struct domain_generic { + pthread_mutex_t mutex; + uint order; + struct domain_generic **prev; + struct lock_order *locked_by; + const char *name; +}; + +#define DOMAIN_INIT(_name, _order) { .mutex = PTHREAD_MUTEX_INITIALIZER, .name = _name, .order = _order } + +static struct domain_generic the_bird_domain_gen = DOMAIN_INIT("The BIRD", OFFSETOF(struct lock_order, the_bird)); + +DOMAIN(the_bird) the_bird_domain = { .the_bird = &the_bird_domain_gen }; + +struct domain_generic * +domain_new(const char *name, uint order) +{ + ASSERT_DIE(order < sizeof(struct lock_order)); + struct domain_generic *dg = xmalloc(sizeof(struct domain_generic)); + *dg = (struct domain_generic) DOMAIN_INIT(name, order); + return dg; +} + +void +domain_free(struct domain_generic *dg) +{ + pthread_mutex_destroy(&dg->mutex); + xfree(dg); +} + +uint dg_order(struct domain_generic *dg) +{ + return dg->order; +} + +void do_lock(struct domain_generic *dg, struct domain_generic **lsp) +{ + if ((char *) lsp - (char *) &locking_stack != dg->order) + bug("Trying to lock on bad position: order=%u, lsp=%p, base=%p", dg->order, lsp, &locking_stack); + + if (lsp <= last_locked) + bug("Trying to lock in a bad order"); + if (*lsp) + bug("Inconsistent locking stack state on lock"); + + btime lock_begin = current_time(); + pthread_mutex_lock(&dg->mutex); + btime duration = current_time() - lock_begin; + if (config && (duration > config->watchdog_warning)) + log(L_WARN "Locking of %s took %d ms", dg->name, (int) (duration TO_MS)); + + if (dg->prev || dg->locked_by) + bug("Previous unlock not finished correctly"); + dg->prev = last_locked; + *lsp = dg; + last_locked = lsp; + dg->locked_by = &locking_stack; +} + +void do_unlock(struct domain_generic *dg, struct domain_generic **lsp) +{ + if ((char *) lsp - (char *) &locking_stack != dg->order) + bug("Trying to unlock on bad position: order=%u, lsp=%p, base=%p", dg->order, lsp, &locking_stack); + + if (dg->locked_by != &locking_stack) + bug("Inconsistent domain state on unlock"); + if ((last_locked != lsp) || (*lsp != dg)) + bug("Inconsistent locking stack state on unlock"); + dg->locked_by = NULL; + last_locked = dg->prev; + *lsp = NULL; + dg->prev = NULL; + pthread_mutex_unlock(&dg->mutex); +} |