diff options
Diffstat (limited to 'create.c')
| -rw-r--r-- | create.c | 34 |
1 files changed, 16 insertions, 18 deletions
@@ -42,26 +42,24 @@ pthread_create(pthread_t *thread, const pthread_attr_t *attr, /* Use and modify attr_copy. Only after we've succeeded in creating the new thread can we modify any passed-in structures. - We use one malloc() to get all of our heap space and then allocate - it further. + To save time we use one malloc() to get all of our heap space and + then allocate it further. */ - if (NULL == (privmem = (char) malloc(sizeof(pthread_attr_t) + - sizeof(_pthread_cleanup_stack_t) + - sizeof(DWORD)))) { + + if (NULL == + (privmem = (char) malloc(RND_SIZEOF(pthread_attr_t) + + RND_SIZEOF(_pthread_cleanup_stack_t)))) { return EAGAIN; } attr_copy = (pthread_attr_t *) privmem; - /* Force the next to a DWORD boundary. - This is all compile time arithmetic. + + /* Force cleanup_stack to start at a DWORD boundary within privmem. */ cleanup_stack = - (_pthread_cleanup_stack_t *) &privmem[((sizeof(pthread_attr_t) / - sizeof(DWORD)) + 1) - * sizeof(DWORD)]; + (_pthread_cleanup_stack_t *) &privmem[RND_SIZEOF(pthread_attr_t)]; (void) memcpy(attr_copy, attr); - /* CRITICAL SECTION */ pthread_mutex_lock(&_pthread_count_mutex); @@ -82,7 +80,10 @@ pthread_create(pthread_t *thread, const pthread_attr_t *attr, break; } - flags = 1; /* Start suspended and resume at the last moment */ + flags = 1; /* Start suspended and resume at the last moment to avoid + race conditions, ie. where a thread may enquire it's + attributes before we finish storing them away. + */ handle = (HANDLE) _beginthreadex(security, stack, @@ -92,22 +93,21 @@ pthread_create(pthread_t *thread, const pthread_attr_t *attr, &threadID); if (handle != NULL) { - /* We have a new thread */ _pthread_threads_count++; /* The hash table works as follows: hash into the table, if the slot is occupied then start single stepping from there until we find an available slot. - - There is at least one slot available at this point. */ t = _PTHREAD_HASH_INDEX(handle); while ((_pthread_threads_table[t])->thread != NULL) { t++; + if (t == PTHREAD_THREADS_MAX) - t = 0; /* Wrap around to the first slot */ + t = 0; /* Wrap to the top of the table. */ } + if ((_pthread_threads_table[t])->thread != NULL) { /* INTERNAL ERROR */ } else { @@ -131,8 +131,6 @@ pthread_create(pthread_t *thread, const pthread_attr_t *attr, (void) memcpy(attr, attr_copy); /* POSIX threads are always running after creation. - Start the thread only after passed-in structures have been - modified to avoid race conditions. */ ResumeThread(handle); } else { |