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authorRich Felker <dalias@aerifal.cx>2011-03-17 20:41:37 -0400
committerRich Felker <dalias@aerifal.cx>2011-03-17 20:41:37 -0400
commit047e434ef5fd5437a74f98f63c40a77a683f7f3f (patch)
tree30102ca55dc34c2b5ec078e3b3ab7891abcccb5f /src/thread
parent18c7ea8055cf733f168d2c74d7cc8523a360f5f1 (diff)
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implement robust mutexes
some of this code should be cleaned up, e.g. using macros for some of the bit flags, masks, etc. nonetheless, the code is believed to be working and correct at this point.
Diffstat (limited to 'src/thread')
-rw-r--r--src/thread/pthread_mutex_consistent.c10
-rw-r--r--src/thread/pthread_mutex_init.c2
-rw-r--r--src/thread/pthread_mutex_lock.c6
-rw-r--r--src/thread/pthread_mutex_timedlock.c3
-rw-r--r--src/thread/pthread_mutex_trylock.c38
-rw-r--r--src/thread/pthread_mutex_unlock.c13
-rw-r--r--src/thread/pthread_mutexattr_getrobust.c7
-rw-r--r--src/thread/pthread_mutexattr_setrobust.c9
8 files changed, 78 insertions, 10 deletions
diff --git a/src/thread/pthread_mutex_consistent.c b/src/thread/pthread_mutex_consistent.c
new file mode 100644
index 00000000..7dfb904f
--- /dev/null
+++ b/src/thread/pthread_mutex_consistent.c
@@ -0,0 +1,10 @@
+#include "pthread_impl.h"
+
+int pthread_mutex_consistent(pthread_mutex_t *m)
+{
+ if (m->_m_type < 8) return EINVAL;
+ if ((m->_m_lock & 0x3fffffff) != pthread_self()->tid)
+ return EPERM;
+ m->_m_type -= 8;
+ return 0;
+}
diff --git a/src/thread/pthread_mutex_init.c b/src/thread/pthread_mutex_init.c
index 6e23df13..75ddf02b 100644
--- a/src/thread/pthread_mutex_init.c
+++ b/src/thread/pthread_mutex_init.c
@@ -3,6 +3,6 @@
int pthread_mutex_init(pthread_mutex_t *m, const pthread_mutexattr_t *a)
{
memset(m, 0, sizeof *m);
- if (a) m->_m_type = *a & 3;
+ if (a) m->_m_type = *a & 7;
return 0;
}
diff --git a/src/thread/pthread_mutex_lock.c b/src/thread/pthread_mutex_lock.c
index 56111ec8..477b3d80 100644
--- a/src/thread/pthread_mutex_lock.c
+++ b/src/thread/pthread_mutex_lock.c
@@ -4,9 +4,9 @@ int pthread_mutex_lock(pthread_mutex_t *m)
{
int r;
while ((r=pthread_mutex_trylock(m)) == EBUSY) {
- if (!(r=m->_m_lock)) continue;
- if (m->_m_type == PTHREAD_MUTEX_ERRORCHECK
- && r == pthread_self()->tid)
+ if (!(r=m->_m_lock) || (r&0x40000000)) continue;
+ if ((m->_m_type&3) == PTHREAD_MUTEX_ERRORCHECK
+ && (r&0x1fffffff) == pthread_self()->tid)
return EDEADLK;
__wait(&m->_m_lock, &m->_m_waiters, r, 0);
}
diff --git a/src/thread/pthread_mutex_timedlock.c b/src/thread/pthread_mutex_timedlock.c
index 20ce0128..f1c3eed7 100644
--- a/src/thread/pthread_mutex_timedlock.c
+++ b/src/thread/pthread_mutex_timedlock.c
@@ -4,8 +4,9 @@ int pthread_mutex_timedlock(pthread_mutex_t *m, const struct timespec *at)
{
int r, w=0;
while ((r=pthread_mutex_trylock(m)) == EBUSY) {
+ if (!(r=m->_m_lock) || (r&0x40000000)) continue;
if (!w) a_inc(&m->_m_waiters), w++;
- if (__timedwait(&m->_m_lock, 1, CLOCK_REALTIME, at, 0) == ETIMEDOUT) {
+ if (__timedwait(&m->_m_lock, r, CLOCK_REALTIME, at, 0) == ETIMEDOUT) {
if (w) a_dec(&m->_m_waiters);
return ETIMEDOUT;
}
diff --git a/src/thread/pthread_mutex_trylock.c b/src/thread/pthread_mutex_trylock.c
index de57ff9e..f48aaade 100644
--- a/src/thread/pthread_mutex_trylock.c
+++ b/src/thread/pthread_mutex_trylock.c
@@ -3,19 +3,51 @@
int pthread_mutex_trylock(pthread_mutex_t *m)
{
int tid;
+ int own;
+ pthread_t self;
if (m->_m_type == PTHREAD_MUTEX_NORMAL)
return (m->_m_lock || a_swap(&m->_m_lock, 1)) ? EBUSY : 0;
- tid = pthread_self()->tid;
+ self = pthread_self();
+ tid = self->tid | 0x80000000;
- if (m->_m_lock == tid && m->_m_type == PTHREAD_MUTEX_RECURSIVE) {
+ if (m->_m_type >= 4) {
+ if (!self->robust_list.off)
+ syscall2(__NR_set_robust_list,
+ (long)&self->robust_list, 3*sizeof(long));
+ self->robust_list.off = (char*)&m->_m_lock-(char *)&m->_m_next;
+ self->robust_list.pending = &m->_m_next;
+ }
+
+ if (m->_m_lock == tid && (m->_m_type&3) == PTHREAD_MUTEX_RECURSIVE) {
if ((unsigned)m->_m_count >= INT_MAX) return EAGAIN;
m->_m_count++;
return 0;
}
- if (m->_m_lock || a_cas(&m->_m_lock, 0, tid)) return EBUSY;
+ own = m->_m_lock;
+ if ((own && !(own & 0x40000000)) || a_cas(&m->_m_lock, own, tid)!=own)
+ return EBUSY;
+
m->_m_count = 1;
+
+ if (m->_m_type < 4) return 0;
+
+ if (m->_m_type >= 8) {
+ m->_m_lock = 0;
+ return ENOTRECOVERABLE;
+ }
+ m->_m_next = self->robust_list.head;
+ m->_m_prev = &self->robust_list.head;
+ if (self->robust_list.head)
+ self->robust_list.head[-1] = &m->_m_next;
+ self->robust_list.head = &m->_m_next;
+ self->robust_list.pending = 0;
+ if (own) {
+ m->_m_type += 8;
+ return EOWNERDEAD;
+ }
+
return 0;
}
diff --git a/src/thread/pthread_mutex_unlock.c b/src/thread/pthread_mutex_unlock.c
index 3733788d..67aa7ba5 100644
--- a/src/thread/pthread_mutex_unlock.c
+++ b/src/thread/pthread_mutex_unlock.c
@@ -2,14 +2,23 @@
int pthread_mutex_unlock(pthread_mutex_t *m)
{
+ pthread_t self;
+
if (m->_m_type != PTHREAD_MUTEX_NORMAL) {
- if (!m->_m_lock || m->_m_lock != __pthread_self()->tid)
+ self = __pthread_self();
+ if ((m->_m_lock&0x1fffffff) != self->tid)
return EPERM;
- if (m->_m_type == PTHREAD_MUTEX_RECURSIVE && --m->_m_count)
+ if ((m->_m_type&3) == PTHREAD_MUTEX_RECURSIVE && --m->_m_count)
return 0;
+ if (m->_m_type >= 4) {
+ self->robust_list.pending = &m->_m_next;
+ *(void **)m->_m_prev = m->_m_next;
+ if (m->_m_next) ((void **)m->_m_next)[-1] = m->_m_prev;
+ }
}
m->_m_lock = 0;
if (m->_m_waiters) __wake(&m->_m_lock, 1, 0);
+ if (m->_m_type >= 4) self->robust_list.pending = 0;
return 0;
}
diff --git a/src/thread/pthread_mutexattr_getrobust.c b/src/thread/pthread_mutexattr_getrobust.c
new file mode 100644
index 00000000..b83cb7c6
--- /dev/null
+++ b/src/thread/pthread_mutexattr_getrobust.c
@@ -0,0 +1,7 @@
+#include "pthread_impl.h"
+
+int pthread_mutexattr_getrobust(const pthread_mutexattr_t *a, int *robust)
+{
+ *robust = *a / 4U % 2;
+ return 0;
+}
diff --git a/src/thread/pthread_mutexattr_setrobust.c b/src/thread/pthread_mutexattr_setrobust.c
new file mode 100644
index 00000000..4a296ba1
--- /dev/null
+++ b/src/thread/pthread_mutexattr_setrobust.c
@@ -0,0 +1,9 @@
+#include "pthread_impl.h"
+
+int pthread_mutexattr_setrobust(pthread_mutexattr_t *a, int robust)
+{
+ if (robust > 1U) return EINVAL;
+ *a &= ~4;
+ *a |= robust*4;
+ return 0;
+}