From 1db83a507a9ae287815d62733d1337074993b433 Mon Sep 17 00:00:00 2001 From: Maria Matejka Date: Thu, 4 Feb 2021 15:52:42 +0100 Subject: Locking subsystem: Just a global BIRD lock to begin with. --- lib/locking.h | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100644 lib/locking.h (limited to 'lib/locking.h') diff --git a/lib/locking.h b/lib/locking.h new file mode 100644 index 00000000..eb1bc8fa --- /dev/null +++ b/lib/locking.h @@ -0,0 +1,46 @@ +/* + * BIRD Library -- Locking + * + * (c) 2020--2021 Maria Matejka + * + * Can be freely distributed and used under the terms of the GNU GPL. + */ + +#ifndef _BIRD_LOCKING_H_ +#define _BIRD_LOCKING_H_ + +struct domain_generic; + +/* Here define the global lock order; first to last. */ +struct lock_order { + struct domain_generic *the_bird; +}; + +#define LOCK_ORDER_DEPTH (sizeof(struct lock_order) / sizeof(struct domain_generic *)) + +extern _Thread_local struct lock_order locking_stack; +extern _Thread_local struct domain_generic **last_locked; + +#define DOMAIN(type) struct domain__##type +#define DEFINE_DOMAIN(type) DOMAIN(type) { struct domain_generic *type; } + +#define DOMAIN_NEW(type, name) (DOMAIN(type)) { .type = domain_new(name) } +struct domain_generic *domain_new(const char *name); + +#define DOMAIN_NULL(type) (DOMAIN(type)) {} + +#define LOCK_DOMAIN(type, d) do_lock(((d).type), &(locking_stack.type)) +#define UNLOCK_DOMAIN(type, d) do_unlock(((d).type), &(locking_stack.type)) + +/* Internal for locking */ +void do_lock(struct domain_generic *dg, struct domain_generic **lsp); +void do_unlock(struct domain_generic *dg, struct domain_generic **lsp); + +/* Use with care. To be removed in near future. */ +DEFINE_DOMAIN(the_bird); +extern DOMAIN(the_bird) the_bird_domain; + +#define the_bird_lock() LOCK_DOMAIN(the_bird, the_bird_domain) +#define the_bird_unlock() UNLOCK_DOMAIN(the_bird, the_bird_domain) + +#endif -- cgit v1.2.3 From df3264f51ff38c9366398564a9d342a26bc83f37 Mon Sep 17 00:00:00 2001 From: Maria Matejka Date: Mon, 24 May 2021 13:41:23 +0200 Subject: Lock position checking allows for safe lock unions --- lib/locking.h | 6 ++---- sysdep/unix/coroutine.c | 22 +++++++++++++++------- 2 files changed, 17 insertions(+), 11 deletions(-) (limited to 'lib/locking.h') diff --git a/lib/locking.h b/lib/locking.h index eb1bc8fa..eef60154 100644 --- a/lib/locking.h +++ b/lib/locking.h @@ -16,16 +16,14 @@ struct lock_order { struct domain_generic *the_bird; }; -#define LOCK_ORDER_DEPTH (sizeof(struct lock_order) / sizeof(struct domain_generic *)) - extern _Thread_local struct lock_order locking_stack; extern _Thread_local struct domain_generic **last_locked; #define DOMAIN(type) struct domain__##type #define DEFINE_DOMAIN(type) DOMAIN(type) { struct domain_generic *type; } -#define DOMAIN_NEW(type, name) (DOMAIN(type)) { .type = domain_new(name) } -struct domain_generic *domain_new(const char *name); +#define DOMAIN_NEW(type, name) (DOMAIN(type)) { .type = domain_new(name, OFFSETOF(struct lock_order, type)) } +struct domain_generic *domain_new(const char *name, uint order); #define DOMAIN_NULL(type) (DOMAIN(type)) {} diff --git a/sysdep/unix/coroutine.c b/sysdep/unix/coroutine.c index 71847505..2eba142c 100644 --- a/sysdep/unix/coroutine.c +++ b/sysdep/unix/coroutine.c @@ -44,26 +44,31 @@ * 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) { .mutex = PTHREAD_MUTEX_INITIALIZER, .name = _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"); +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) +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); + *dg = (struct domain_generic) DOMAIN_INIT(name, order); return dg; } @@ -74,11 +79,11 @@ domain_free(struct domain_generic *dg) xfree(dg); } -_Thread_local struct lock_order locking_stack = {}; -_Thread_local struct domain_generic **last_locked = NULL; - 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) @@ -96,6 +101,9 @@ void do_lock(struct domain_generic *dg, struct domain_generic **lsp) 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)) -- cgit v1.2.3