-/* Copyright (C) 2002,2003,2004,2005,2006,2007 Free Software Foundation, Inc.
+/* Copyright (C) 2002-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
- License along with the GNU C Library; if not, write to the Free
- Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
- 02111-1307 USA. */
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
#include <assert.h>
#include <errno.h>
#include <sys/mman.h>
#include <sys/param.h>
#include <dl-sysdep.h>
+#include <dl-tls.h>
#include <tls.h>
+#include <list.h>
#include <lowlevellock.h>
+#include <futex-internal.h>
+#include <kernel-features.h>
+#include <stack-aliasing.h>
#ifndef NEED_SEPARATE_REGISTER_STACK
#endif
-/* Let the architecture add some flags to the mmap() call used to
- allocate stacks. */
-#ifndef ARCH_MAP_FLAGS
-# define ARCH_MAP_FLAGS 0
+/* Newer kernels have the MAP_STACK flag to indicate a mapping is used for
+ a stack. Use it when possible. */
+#ifndef MAP_STACK
+# define MAP_STACK 0
#endif
/* This yields the pointer that TLS support code calls the thread pointer. */
static size_t stack_cache_actsize;
/* Mutex protecting this variable. */
-static lll_lock_t stack_cache_lock = LLL_LOCK_INITIALIZER;
+static int stack_cache_lock = LLL_LOCK_INITIALIZER;
/* List of queued stack frames. */
static LIST_HEAD (stack_cache);
/* List of the stacks in use. */
static LIST_HEAD (stack_used);
+/* We need to record what list operations we are going to do so that,
+ in case of an asynchronous interruption due to a fork() call, we
+ can correct for the work. */
+static uintptr_t in_flight_stack;
+
/* List of the threads with user provided stacks in use. No need to
initialize this, since it's done in __pthread_initialize_minimal. */
list_t __stack_user __attribute__ ((nocommon));
hidden_data_def (__stack_user)
-#if COLORING_INCREMENT != 0
-/* Number of threads created. */
-static unsigned int nptl_ncreated;
-#endif
-
/* Check whether the stack is still used or not. */
#define FREE_P(descr) ((descr)->tid <= 0)
+static void
+stack_list_del (list_t *elem)
+{
+ in_flight_stack = (uintptr_t) elem;
+
+ atomic_write_barrier ();
+
+ list_del (elem);
+
+ atomic_write_barrier ();
+
+ in_flight_stack = 0;
+}
+
+
+static void
+stack_list_add (list_t *elem, list_t *list)
+{
+ in_flight_stack = (uintptr_t) elem | 1;
+
+ atomic_write_barrier ();
+
+ list_add (elem, list);
+
+ atomic_write_barrier ();
+
+ in_flight_stack = 0;
+}
+
+
/* We create a double linked list of all cache entries. Double linked
because this allows removing entries from the end. */
struct pthread *result = NULL;
list_t *entry;
- lll_lock (stack_cache_lock);
+ lll_lock (stack_cache_lock, LLL_PRIVATE);
/* Search the cache for a matching entry. We search for the
smallest stack which has at least the required size. Note that
|| __builtin_expect (result->stackblock_size > 4 * size, 0))
{
/* Release the lock. */
- lll_unlock (stack_cache_lock);
+ lll_unlock (stack_cache_lock, LLL_PRIVATE);
return NULL;
}
+ /* Don't allow setxid until cloned. */
+ result->setxid_futex = -1;
+
/* Dequeue the entry. */
- list_del (&result->list);
+ stack_list_del (&result->list);
/* And add to the list of stacks in use. */
- list_add (&result->list, &stack_used);
+ stack_list_add (&result->list, &stack_used);
/* And decrease the cache size. */
stack_cache_actsize -= result->stackblock_size;
/* Release the lock early. */
- lll_unlock (stack_cache_lock);
+ lll_unlock (stack_cache_lock, LLL_PRIVATE);
/* Report size and location of the stack to the caller. */
*sizep = result->stackblock_size;
/* Clear the DTV. */
dtv_t *dtv = GET_DTV (TLS_TPADJ (result));
+ for (size_t cnt = 0; cnt < dtv[-1].counter; ++cnt)
+ free (dtv[1 + cnt].pointer.to_free);
memset (dtv, '\0', (dtv[-1].counter + 1) * sizeof (dtv_t));
/* Re-initialize the TLS. */
if (FREE_P (curr))
{
/* Unlink the block. */
- list_del (entry);
+ stack_list_del (entry);
/* Account for the freed memory. */
stack_cache_actsize -= curr->stackblock_size;
/* Remove this block. This should never fail. If it does
something is really wrong. */
- if (munmap (curr->stackblock, curr->stackblock_size) != 0)
+ if (__munmap (curr->stackblock, curr->stackblock_size) != 0)
abort ();
/* Maybe we have freed enough. */
}
}
+/* Free all the stacks on cleanup. */
+void
+__nptl_stacks_freeres (void)
+{
+ free_stacks (0);
+}
/* Add a stack frame which is not used anymore to the stack. Must be
called with the cache lock held. */
/* We unconditionally add the stack to the list. The memory may
still be in use but it will not be reused until the kernel marks
the stack as not used anymore. */
- list_add (&stack->list, &stack_cache);
+ stack_list_add (&stack->list, &stack_cache);
stack_cache_actsize += stack->stackblock_size;
- if (__builtin_expect (stack_cache_actsize > stack_cache_maxsize, 0))
+ if (__glibc_unlikely (stack_cache_actsize > stack_cache_maxsize))
free_stacks (stack_cache_maxsize);
}
-/* This function is called indirectly from the freeres code in libc. */
-void
-__free_stack_cache (void)
-{
- free_stacks (0);
-}
-
-
static int
-internal_function
change_stack_perm (struct pthread *pd
#ifdef NEED_SEPARATE_REGISTER_STACK
, size_t pagemask
#else
# error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP"
#endif
- if (mprotect (stack, len, PROT_READ | PROT_WRITE | PROT_EXEC) != 0)
+ if (__mprotect (stack, len, PROT_READ | PROT_WRITE | PROT_EXEC) != 0)
return errno;
return 0;
}
+/* Return the guard page position on allocated stack. */
+static inline char *
+__attribute ((always_inline))
+guard_position (void *mem, size_t size, size_t guardsize, struct pthread *pd,
+ size_t pagesize_m1)
+{
+#ifdef NEED_SEPARATE_REGISTER_STACK
+ return mem + (((size - guardsize) / 2) & ~pagesize_m1);
+#elif _STACK_GROWS_DOWN
+ return mem;
+#elif _STACK_GROWS_UP
+ return (char *) (((uintptr_t) pd - guardsize) & ~pagesize_m1);
+#endif
+}
+
+/* Based on stack allocated with PROT_NONE, setup the required portions with
+ 'prot' flags based on the guard page position. */
+static inline int
+setup_stack_prot (char *mem, size_t size, char *guard, size_t guardsize,
+ const int prot)
+{
+ char *guardend = guard + guardsize;
+#if _STACK_GROWS_DOWN && !defined(NEED_SEPARATE_REGISTER_STACK)
+ /* As defined at guard_position, for architectures with downward stack
+ the guard page is always at start of the allocated area. */
+ if (__mprotect (guardend, size - guardsize, prot) != 0)
+ return errno;
+#else
+ size_t mprots1 = (uintptr_t) guard - (uintptr_t) mem;
+ if (__mprotect (mem, mprots1, prot) != 0)
+ return errno;
+ size_t mprots2 = ((uintptr_t) mem + size) - (uintptr_t) guardend;
+ if (__mprotect (guardend, mprots2, prot) != 0)
+ return errno;
+#endif
+ return 0;
+}
+/* Mark the memory of the stack as usable to the kernel. It frees everything
+ except for the space used for the TCB itself. */
+static inline void
+__always_inline
+advise_stack_range (void *mem, size_t size, uintptr_t pd, size_t guardsize)
+{
+ uintptr_t sp = (uintptr_t) CURRENT_STACK_FRAME;
+ size_t pagesize_m1 = __getpagesize () - 1;
+#if _STACK_GROWS_DOWN && !defined(NEED_SEPARATE_REGISTER_STACK)
+ size_t freesize = (sp - (uintptr_t) mem) & ~pagesize_m1;
+ assert (freesize < size);
+ if (freesize > PTHREAD_STACK_MIN)
+ __madvise (mem, freesize - PTHREAD_STACK_MIN, MADV_DONTNEED);
+#else
+ /* Page aligned start of memory to free (higher than or equal
+ to current sp plus the minimum stack size). */
+ uintptr_t freeblock = (sp + PTHREAD_STACK_MIN + pagesize_m1) & ~pagesize_m1;
+ uintptr_t free_end = (pd - guardsize) & ~pagesize_m1;
+ if (free_end > freeblock)
+ {
+ size_t freesize = free_end - freeblock;
+ assert (freesize < size);
+ __madvise ((void*) freeblock, freesize, MADV_DONTNEED);
+ }
+#endif
+}
+
+/* Returns a usable stack for a new thread either by allocating a
+ new stack or reusing a cached stack of sufficient size.
+ ATTR must be non-NULL and point to a valid pthread_attr.
+ PDP must be non-NULL. */
static int
allocate_stack (const struct pthread_attr *attr, struct pthread **pdp,
ALLOCATE_STACK_PARMS)
struct pthread *pd;
size_t size;
size_t pagesize_m1 = __getpagesize () - 1;
- void *stacktop;
- assert (attr != NULL);
assert (powerof2 (pagesize_m1 + 1));
assert (TCB_ALIGNMENT >= STACK_ALIGN);
/* Get the stack size from the attribute if it is set. Otherwise we
use the default we determined at start time. */
- size = attr->stacksize ?: __default_stacksize;
+ if (attr->stacksize != 0)
+ size = attr->stacksize;
+ else
+ {
+ lll_lock (__default_pthread_attr_lock, LLL_PRIVATE);
+ size = __default_pthread_attr.stacksize;
+ lll_unlock (__default_pthread_attr_lock, LLL_PRIVATE);
+ }
/* Get memory for the stack. */
- if (__builtin_expect (attr->flags & ATTR_FLAG_STACKADDR, 0))
+ if (__glibc_unlikely (attr->flags & ATTR_FLAG_STACKADDR))
{
uintptr_t adj;
+ char *stackaddr = (char *) attr->stackaddr;
+
+ /* Assume the same layout as the _STACK_GROWS_DOWN case, with struct
+ pthread at the top of the stack block. Later we adjust the guard
+ location and stack address to match the _STACK_GROWS_UP case. */
+ if (_STACK_GROWS_UP)
+ stackaddr += attr->stacksize;
/* If the user also specified the size of the stack make sure it
is large enough. */
/* Adjust stack size for alignment of the TLS block. */
#if TLS_TCB_AT_TP
- adj = ((uintptr_t) attr->stackaddr - TLS_TCB_SIZE)
+ adj = ((uintptr_t) stackaddr - TLS_TCB_SIZE)
& __static_tls_align_m1;
assert (size > adj + TLS_TCB_SIZE);
#elif TLS_DTV_AT_TP
- adj = ((uintptr_t) attr->stackaddr - __static_tls_size)
+ adj = ((uintptr_t) stackaddr - __static_tls_size)
& __static_tls_align_m1;
assert (size > adj);
#endif
the stack. It is the user's responsibility to do this if it
is wanted. */
#if TLS_TCB_AT_TP
- pd = (struct pthread *) ((uintptr_t) attr->stackaddr
+ pd = (struct pthread *) ((uintptr_t) stackaddr
- TLS_TCB_SIZE - adj);
#elif TLS_DTV_AT_TP
- pd = (struct pthread *) (((uintptr_t) attr->stackaddr
- - __static_tls_size - adj)
+ pd = (struct pthread *) (((uintptr_t) stackaddr
+ - __static_tls_size - adj)
- TLS_PRE_TCB_SIZE);
#endif
pd->specific[0] = pd->specific_1stblock;
/* Remember the stack-related values. */
- pd->stackblock = (char *) attr->stackaddr - size;
+ pd->stackblock = (char *) stackaddr - size;
pd->stackblock_size = size;
/* This is a user-provided stack. It will not be queued in the
__pthread_multiple_threads = *__libc_multiple_threads_ptr = 1;
#endif
-#ifndef __ASSUME_PRIVATE_FUTEX
- /* The thread must know when private futexes are supported. */
- pd->header.private_futex = THREAD_GETMEM (THREAD_SELF,
- header.private_futex);
-#endif
-
#ifdef NEED_DL_SYSINFO
- /* Copy the sysinfo value from the parent. */
- THREAD_SYSINFO(pd) = THREAD_SELF_SYSINFO;
+ SETUP_THREAD_SYSINFO (pd);
#endif
- /* The process ID is also the same as that of the caller. */
- pd->pid = THREAD_GETMEM (THREAD_SELF, pid);
+ /* Don't allow setxid until cloned. */
+ pd->setxid_futex = -1;
/* Allocate the DTV for this thread. */
if (_dl_allocate_tls (TLS_TPADJ (pd)) == NULL)
{
/* Something went wrong. */
assert (errno == ENOMEM);
- return EAGAIN;
+ return errno;
}
/* Prepare to modify global data. */
- lll_lock (stack_cache_lock);
+ lll_lock (stack_cache_lock, LLL_PRIVATE);
/* And add to the list of stacks in use. */
list_add (&pd->list, &__stack_user);
- lll_unlock (stack_cache_lock);
+ lll_unlock (stack_cache_lock, LLL_PRIVATE);
}
else
{
const int prot = (PROT_READ | PROT_WRITE
| ((GL(dl_stack_flags) & PF_X) ? PROT_EXEC : 0));
-#if COLORING_INCREMENT != 0
- /* Add one more page for stack coloring. Don't do it for stacks
- with 16 times pagesize or larger. This might just cause
- unnecessary misalignment. */
- if (size <= 16 * pagesize_m1)
- size += pagesize_m1 + 1;
-#endif
-
/* Adjust the stack size for alignment. */
size &= ~__static_tls_align_m1;
assert (size != 0);
/* Make sure the size of the stack is enough for the guard and
eventually the thread descriptor. */
guardsize = (attr->guardsize + pagesize_m1) & ~pagesize_m1;
+ if (guardsize < attr->guardsize || size + guardsize < guardsize)
+ /* Arithmetic overflow. */
+ return EINVAL;
+ size += guardsize;
if (__builtin_expect (size < ((guardsize + __static_tls_size
+ MINIMAL_REST_STACK + pagesize_m1)
& ~pagesize_m1),
size += pagesize_m1 + 1;
#endif
- mem = mmap (NULL, size, prot,
- MAP_PRIVATE | MAP_ANONYMOUS | ARCH_MAP_FLAGS, -1, 0);
+ /* If a guard page is required, avoid committing memory by first
+ allocate with PROT_NONE and then reserve with required permission
+ excluding the guard page. */
+ mem = __mmap (NULL, size, (guardsize == 0) ? prot : PROT_NONE,
+ MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
- if (__builtin_expect (mem == MAP_FAILED, 0))
- {
-#ifdef ARCH_RETRY_MMAP
- mem = ARCH_RETRY_MMAP (size);
- if (__builtin_expect (mem == MAP_FAILED, 0))
-#endif
- return errno;
- }
+ if (__glibc_unlikely (mem == MAP_FAILED))
+ return errno;
/* SIZE is guaranteed to be greater than zero.
So we can never get a null pointer back from mmap. */
assert (mem != NULL);
-#if COLORING_INCREMENT != 0
- /* Atomically increment NCREATED. */
- unsigned int ncreated = atomic_increment_val (&nptl_ncreated);
-
- /* We chose the offset for coloring by incrementing it for
- every new thread by a fixed amount. The offset used
- module the page size. Even if coloring would be better
- relative to higher alignment values it makes no sense to
- do it since the mmap() interface does not allow us to
- specify any alignment for the returned memory block. */
- size_t coloring = (ncreated * COLORING_INCREMENT) & pagesize_m1;
-
- /* Make sure the coloring offsets does not disturb the alignment
- of the TCB and static TLS block. */
- if (__builtin_expect ((coloring & __static_tls_align_m1) != 0, 0))
- coloring = (((coloring + __static_tls_align_m1)
- & ~(__static_tls_align_m1))
- & ~pagesize_m1);
-#else
- /* Unless specified we do not make any adjustments. */
-# define coloring 0
-#endif
-
/* Place the thread descriptor at the end of the stack. */
#if TLS_TCB_AT_TP
- pd = (struct pthread *) ((char *) mem + size - coloring) - 1;
+ pd = (struct pthread *) ((char *) mem + size) - 1;
#elif TLS_DTV_AT_TP
- pd = (struct pthread *) ((((uintptr_t) mem + size - coloring
+ pd = (struct pthread *) ((((uintptr_t) mem + size
- __static_tls_size)
& ~__static_tls_align_m1)
- TLS_PRE_TCB_SIZE);
#endif
+ /* Now mprotect the required region excluding the guard area. */
+ if (__glibc_likely (guardsize > 0))
+ {
+ char *guard = guard_position (mem, size, guardsize, pd,
+ pagesize_m1);
+ if (setup_stack_prot (mem, size, guard, guardsize, prot) != 0)
+ {
+ __munmap (mem, size);
+ return errno;
+ }
+ }
+
/* Remember the stack-related values. */
pd->stackblock = mem;
pd->stackblock_size = size;
+ /* Update guardsize for newly allocated guardsize to avoid
+ an mprotect in guard resize below. */
+ pd->guardsize = guardsize;
/* We allocated the first block thread-specific data array.
This address will not change for the lifetime of this
__pthread_multiple_threads = *__libc_multiple_threads_ptr = 1;
#endif
-#ifndef __ASSUME_PRIVATE_FUTEX
- /* The thread must know when private futexes are supported. */
- pd->header.private_futex = THREAD_GETMEM (THREAD_SELF,
- header.private_futex);
-#endif
-
#ifdef NEED_DL_SYSINFO
- /* Copy the sysinfo value from the parent. */
- THREAD_SYSINFO(pd) = THREAD_SELF_SYSINFO;
+ SETUP_THREAD_SYSINFO (pd);
#endif
- /* The process ID is also the same as that of the caller. */
- pd->pid = THREAD_GETMEM (THREAD_SELF, pid);
+ /* Don't allow setxid until cloned. */
+ pd->setxid_futex = -1;
/* Allocate the DTV for this thread. */
if (_dl_allocate_tls (TLS_TPADJ (pd)) == NULL)
assert (errno == ENOMEM);
/* Free the stack memory we just allocated. */
- (void) munmap (mem, size);
+ (void) __munmap (mem, size);
- return EAGAIN;
+ return errno;
}
/* Prepare to modify global data. */
- lll_lock (stack_cache_lock);
+ lll_lock (stack_cache_lock, LLL_PRIVATE);
/* And add to the list of stacks in use. */
- list_add (&pd->list, &stack_used);
+ stack_list_add (&pd->list, &stack_used);
- lll_unlock (stack_cache_lock);
+ lll_unlock (stack_cache_lock, LLL_PRIVATE);
/* There might have been a race. Another thread might have
if (err != 0)
{
/* Free the stack memory we just allocated. */
- (void) munmap (mem, size);
+ (void) __munmap (mem, size);
return err;
}
}
/* Create or resize the guard area if necessary. */
- if (__builtin_expect (guardsize > pd->guardsize, 0))
+ if (__glibc_unlikely (guardsize > pd->guardsize))
{
-#ifdef NEED_SEPARATE_REGISTER_STACK
- char *guard = mem + (((size - guardsize) / 2) & ~pagesize_m1);
-#elif _STACK_GROWS_DOWN
- char *guard = mem;
-# elif _STACK_GROWS_UP
- char *guard = (char *) (((uintptr_t) pd - guardsize) & ~pagesize_m1);
-#endif
- if (mprotect (guard, guardsize, PROT_NONE) != 0)
+ char *guard = guard_position (mem, size, guardsize, pd,
+ pagesize_m1);
+ if (__mprotect (guard, guardsize, PROT_NONE) != 0)
{
- int err;
mprot_error:
- err = errno;
-
- lll_lock (stack_cache_lock);
+ lll_lock (stack_cache_lock, LLL_PRIVATE);
/* Remove the thread from the list. */
- list_del (&pd->list);
+ stack_list_del (&pd->list);
- lll_unlock (stack_cache_lock);
+ lll_unlock (stack_cache_lock, LLL_PRIVATE);
/* Get rid of the TLS block we allocated. */
_dl_deallocate_tls (TLS_TPADJ (pd), false);
of memory caused problems we better do not use it
anymore. Uh, and we ignore possible errors. There
is nothing we could do. */
- (void) munmap (mem, size);
+ (void) __munmap (mem, size);
- return err;
+ return errno;
}
pd->guardsize = guardsize;
char *oldguard = mem + (((size - pd->guardsize) / 2) & ~pagesize_m1);
if (oldguard < guard
- && mprotect (oldguard, guard - oldguard, prot) != 0)
+ && __mprotect (oldguard, guard - oldguard, prot) != 0)
goto mprot_error;
- if (mprotect (guard + guardsize,
+ if (__mprotect (guard + guardsize,
oldguard + pd->guardsize - guard - guardsize,
prot) != 0)
goto mprot_error;
#elif _STACK_GROWS_DOWN
- if (mprotect ((char *) mem + guardsize, pd->guardsize - guardsize,
+ if (__mprotect ((char *) mem + guardsize, pd->guardsize - guardsize,
prot) != 0)
goto mprot_error;
#elif _STACK_GROWS_UP
- if (mprotect ((char *) pd - pd->guardsize,
- pd->guardsize - guardsize, prot) != 0)
+ char *new_guard = (char *)(((uintptr_t) pd - guardsize)
+ & ~pagesize_m1);
+ char *old_guard = (char *)(((uintptr_t) pd - pd->guardsize)
+ & ~pagesize_m1);
+ /* The guard size difference might be > 0, but once rounded
+ to the nearest page the size difference might be zero. */
+ if (new_guard > old_guard
+ && __mprotect (old_guard, new_guard - old_guard, prot) != 0)
goto mprot_error;
#endif
- offsetof (pthread_mutex_t,
__data.__list.__next));
pd->robust_head.list_op_pending = NULL;
-#ifdef __PTHREAD_MUTEX_HAVE_PREV
+#if __PTHREAD_MUTEX_HAVE_PREV
pd->robust_prev = &pd->robust_head;
#endif
pd->robust_head.list = &pd->robust_head;
/* We place the thread descriptor at the end of the stack. */
*pdp = pd;
-#if TLS_TCB_AT_TP
+#if _STACK_GROWS_DOWN
+ void *stacktop;
+
+# if TLS_TCB_AT_TP
/* The stack begins before the TCB and the static TLS block. */
stacktop = ((char *) (pd + 1) - __static_tls_size);
-#elif TLS_DTV_AT_TP
+# elif TLS_DTV_AT_TP
stacktop = (char *) (pd - 1);
-#endif
+# endif
-#ifdef NEED_SEPARATE_REGISTER_STACK
+# ifdef NEED_SEPARATE_REGISTER_STACK
*stack = pd->stackblock;
*stacksize = stacktop - *stack;
-#elif _STACK_GROWS_DOWN
+# else
*stack = stacktop;
-#elif _STACK_GROWS_UP
+# endif
+#else
*stack = pd->stackblock;
- assert (*stack > 0);
#endif
return 0;
void
-internal_function
__deallocate_stack (struct pthread *pd)
{
- lll_lock (stack_cache_lock);
+ lll_lock (stack_cache_lock, LLL_PRIVATE);
/* Remove the thread from the list of threads with user defined
stacks. */
- list_del (&pd->list);
+ stack_list_del (&pd->list);
/* Not much to do. Just free the mmap()ed memory. Note that we do
not reset the 'used' flag in the 'tid' field. This is done by
the kernel. If no thread has been created yet this field is
still zero. */
- if (__builtin_expect (! pd->user_stack, 1))
+ if (__glibc_likely (! pd->user_stack))
(void) queue_stack (pd);
else
/* Free the memory associated with the ELF TLS. */
_dl_deallocate_tls (TLS_TPADJ (pd), false);
- lll_unlock (stack_cache_lock);
+ lll_unlock (stack_cache_lock, LLL_PRIVATE);
}
int
-internal_function
__make_stacks_executable (void **stack_endp)
{
/* First the main thread's stack. */
const size_t pagemask = ~(__getpagesize () - 1);
#endif
- lll_lock (stack_cache_lock);
+ lll_lock (stack_cache_lock, LLL_PRIVATE);
list_t *runp;
list_for_each (runp, &stack_used)
break;
}
- lll_unlock (stack_cache_lock);
+ lll_unlock (stack_cache_lock, LLL_PRIVATE);
return err;
}
{
struct pthread *self = (struct pthread *) THREAD_SELF;
- /* No locking necessary. The caller is the only stack in use. */
+ /* No locking necessary. The caller is the only stack in use. But
+ we have to be aware that we might have interrupted a list
+ operation. */
+
+ if (in_flight_stack != 0)
+ {
+ bool add_p = in_flight_stack & 1;
+ list_t *elem = (list_t *) (in_flight_stack & ~(uintptr_t) 1);
+
+ if (add_p)
+ {
+ /* We always add at the beginning of the list. So in this case we
+ only need to check the beginning of these lists to see if the
+ pointers at the head of the list are inconsistent. */
+ list_t *l = NULL;
+
+ if (stack_used.next->prev != &stack_used)
+ l = &stack_used;
+ else if (stack_cache.next->prev != &stack_cache)
+ l = &stack_cache;
+
+ if (l != NULL)
+ {
+ assert (l->next->prev == elem);
+ elem->next = l->next;
+ elem->prev = l;
+ l->next = elem;
+ }
+ }
+ else
+ {
+ /* We can simply always replay the delete operation. */
+ elem->next->prev = elem->prev;
+ elem->prev->next = elem->next;
+ }
+ }
/* Mark all stacks except the still running one as free. */
list_t *runp;
/* This marks the stack as free. */
curp->tid = 0;
- /* The PID field must be initialized for the new process. */
- curp->pid = self->pid;
-
/* Account for the size of the stack. */
stack_cache_actsize += curp->stackblock_size;
- }
- }
- /* Reset the PIDs in any cached stacks. */
- list_for_each (runp, &stack_cache)
- {
- struct pthread *curp = list_entry (runp, struct pthread, list);
- curp->pid = self->pid;
+ if (curp->specific_used)
+ {
+ /* Clear the thread-specific data. */
+ memset (curp->specific_1stblock, '\0',
+ sizeof (curp->specific_1stblock));
+
+ curp->specific_used = false;
+
+ for (size_t cnt = 1; cnt < PTHREAD_KEY_1STLEVEL_SIZE; ++cnt)
+ if (curp->specific[cnt] != NULL)
+ {
+ memset (curp->specific[cnt], '\0',
+ sizeof (curp->specific_1stblock));
+
+ /* We have allocated the block which we do not
+ free here so re-set the bit. */
+ curp->specific_used = true;
+ }
+ }
+ }
}
/* Add the stack of all running threads to the cache. */
/* Remove the entry for the current thread to from the cache list
and add it to the list of running threads. Which of the two
lists is decided by the user_stack flag. */
- list_del (&self->list);
+ stack_list_del (&self->list);
/* Re-initialize the lists for all the threads. */
INIT_LIST_HEAD (&stack_used);
INIT_LIST_HEAD (&__stack_user);
- if (__builtin_expect (THREAD_GETMEM (self, user_stack), 0))
+ if (__glibc_unlikely (THREAD_GETMEM (self, user_stack)))
list_add (&self->list, &__stack_user);
else
list_add (&self->list, &stack_used);
/* There is one thread running. */
__nptl_nthreads = 1;
- /* Initialize the lock. */
+ in_flight_stack = 0;
+
+ /* Initialize locks. */
stack_cache_lock = LLL_LOCK_INITIALIZER;
+ __default_pthread_attr_lock = LLL_LOCK_INITIALIZER;
}
{
struct pthread *result = NULL;
- lll_lock (stack_cache_lock);
+ lll_lock (stack_cache_lock, LLL_PRIVATE);
/* Iterate over the list with system-allocated threads first. */
list_t *runp;
}
out:
- lll_unlock (stack_cache_lock);
+ lll_unlock (stack_cache_lock, LLL_PRIVATE);
return result;
}
#endif
+#ifdef SIGSETXID
static void
-internal_function
-setxid_signal_thread (struct xid_command *cmdp, struct pthread *t)
+setxid_mark_thread (struct xid_command *cmdp, struct pthread *t)
{
- if (! IS_DETACHED (t))
+ int ch;
+
+ /* Wait until this thread is cloned. */
+ if (t->setxid_futex == -1
+ && ! atomic_compare_and_exchange_bool_acq (&t->setxid_futex, -2, -1))
+ do
+ futex_wait_simple (&t->setxid_futex, -2, FUTEX_PRIVATE);
+ while (t->setxid_futex == -2);
+
+ /* Don't let the thread exit before the setxid handler runs. */
+ t->setxid_futex = 0;
+
+ do
{
- int ch;
- do
- {
- ch = t->cancelhandling;
+ ch = t->cancelhandling;
- /* If the thread is exiting right now, ignore it. */
- if ((ch & EXITING_BITMASK) != 0)
- return;
+ /* If the thread is exiting right now, ignore it. */
+ if ((ch & EXITING_BITMASK) != 0)
+ {
+ /* Release the futex if there is no other setxid in
+ progress. */
+ if ((ch & SETXID_BITMASK) == 0)
+ {
+ t->setxid_futex = 1;
+ futex_wake (&t->setxid_futex, 1, FUTEX_PRIVATE);
+ }
+ return;
}
- while (atomic_compare_and_exchange_bool_acq (&t->cancelhandling,
- ch | SETXID_BITMASK, ch));
}
+ while (atomic_compare_and_exchange_bool_acq (&t->cancelhandling,
+ ch | SETXID_BITMASK, ch));
+}
+
+
+static void
+setxid_unmark_thread (struct xid_command *cmdp, struct pthread *t)
+{
+ int ch;
+
+ do
+ {
+ ch = t->cancelhandling;
+ if ((ch & SETXID_BITMASK) == 0)
+ return;
+ }
+ while (atomic_compare_and_exchange_bool_acq (&t->cancelhandling,
+ ch & ~SETXID_BITMASK, ch));
+
+ /* Release the futex just in case. */
+ t->setxid_futex = 1;
+ futex_wake (&t->setxid_futex, 1, FUTEX_PRIVATE);
+}
+
+
+static int
+setxid_signal_thread (struct xid_command *cmdp, struct pthread *t)
+{
+ if ((t->cancelhandling & SETXID_BITMASK) == 0)
+ return 0;
int val;
+ pid_t pid = __getpid ();
INTERNAL_SYSCALL_DECL (err);
-#if __ASSUME_TGKILL
- val = INTERNAL_SYSCALL (tgkill, err, 3, THREAD_GETMEM (THREAD_SELF, pid),
- t->tid, SIGSETXID);
-#else
-# ifdef __NR_tgkill
- val = INTERNAL_SYSCALL (tgkill, err, 3, THREAD_GETMEM (THREAD_SELF, pid),
- t->tid, SIGSETXID);
- if (INTERNAL_SYSCALL_ERROR_P (val, err)
- && INTERNAL_SYSCALL_ERRNO (val, err) == ENOSYS)
-# endif
- val = INTERNAL_SYSCALL (tkill, err, 2, t->tid, SIGSETXID);
-#endif
+ val = INTERNAL_SYSCALL_CALL (tgkill, err, pid, t->tid, SIGSETXID);
+ /* If this failed, it must have had not started yet or else exited. */
if (!INTERNAL_SYSCALL_ERROR_P (val, err))
- atomic_increment (&cmdp->cntr);
+ {
+ atomic_increment (&cmdp->cntr);
+ return 1;
+ }
+ else
+ return 0;
}
+/* Check for consistency across set*id system call results. The abort
+ should not happen as long as all privileges changes happen through
+ the glibc wrappers. ERROR must be 0 (no error) or an errno
+ code. */
+void
+attribute_hidden
+__nptl_setxid_error (struct xid_command *cmdp, int error)
+{
+ do
+ {
+ int olderror = cmdp->error;
+ if (olderror == error)
+ break;
+ if (olderror != -1)
+ {
+ /* Mismatch between current and previous results. Save the
+ error value to memory so that is not clobbered by the
+ abort function and preserved in coredumps. */
+ volatile int xid_err __attribute__((unused)) = error;
+ abort ();
+ }
+ }
+ while (atomic_compare_and_exchange_bool_acq (&cmdp->error, error, -1));
+}
int
attribute_hidden
__nptl_setxid (struct xid_command *cmdp)
{
+ int signalled;
int result;
- lll_lock (stack_cache_lock);
+ lll_lock (stack_cache_lock, LLL_PRIVATE);
__xidcmd = cmdp;
cmdp->cntr = 0;
+ cmdp->error = -1;
struct pthread *self = THREAD_SELF;
if (t == self)
continue;
- setxid_signal_thread (cmdp, t);
+ setxid_mark_thread (cmdp, t);
}
/* Now the list with threads using user-allocated stacks. */
if (t == self)
continue;
- setxid_signal_thread (cmdp, t);
+ setxid_mark_thread (cmdp, t);
}
- int cur = cmdp->cntr;
- while (cur != 0)
+ /* Iterate until we don't succeed in signalling anyone. That means
+ we have gotten all running threads, and their children will be
+ automatically correct once started. */
+ do
{
- lll_futex_wait (&cmdp->cntr, cur);
- cur = cmdp->cntr;
+ signalled = 0;
+
+ list_for_each (runp, &stack_used)
+ {
+ struct pthread *t = list_entry (runp, struct pthread, list);
+ if (t == self)
+ continue;
+
+ signalled += setxid_signal_thread (cmdp, t);
+ }
+
+ list_for_each (runp, &__stack_user)
+ {
+ struct pthread *t = list_entry (runp, struct pthread, list);
+ if (t == self)
+ continue;
+
+ signalled += setxid_signal_thread (cmdp, t);
+ }
+
+ int cur = cmdp->cntr;
+ while (cur != 0)
+ {
+ futex_wait_simple ((unsigned int *) &cmdp->cntr, cur,
+ FUTEX_PRIVATE);
+ cur = cmdp->cntr;
+ }
+ }
+ while (signalled != 0);
+
+ /* Clean up flags, so that no thread blocks during exit waiting
+ for a signal which will never come. */
+ list_for_each (runp, &stack_used)
+ {
+ struct pthread *t = list_entry (runp, struct pthread, list);
+ if (t == self)
+ continue;
+
+ setxid_unmark_thread (cmdp, t);
+ }
+
+ list_for_each (runp, &__stack_user)
+ {
+ struct pthread *t = list_entry (runp, struct pthread, list);
+ if (t == self)
+ continue;
+
+ setxid_unmark_thread (cmdp, t);
}
/* This must be last, otherwise the current thread might not have
INTERNAL_SYSCALL_DECL (err);
result = INTERNAL_SYSCALL_NCS (cmdp->syscall_no, err, 3,
cmdp->id[0], cmdp->id[1], cmdp->id[2]);
- if (INTERNAL_SYSCALL_ERROR_P (result, err))
+ int error = 0;
+ if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (result, err)))
{
- __set_errno (INTERNAL_SYSCALL_ERRNO (result, err));
+ error = INTERNAL_SYSCALL_ERRNO (result, err);
+ __set_errno (error);
result = -1;
}
+ __nptl_setxid_error (cmdp, error);
- lll_unlock (stack_cache_lock);
+ lll_unlock (stack_cache_lock, LLL_PRIVATE);
return result;
}
+#endif /* SIGSETXID. */
+
static inline void __attribute__((always_inline))
init_one_static_tls (struct pthread *curp, struct link_map *map)
{
- dtv_t *dtv = GET_DTV (TLS_TPADJ (curp));
# if TLS_TCB_AT_TP
void *dest = (char *) curp - map->l_tls_offset;
# elif TLS_DTV_AT_TP
# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
# endif
- /* Fill in the DTV slot so that a later LD/GD access will find it. */
- dtv[map->l_tls_modid].pointer.val = dest;
- dtv[map->l_tls_modid].pointer.is_static = true;
-
/* Initialize the memory. */
memset (__mempcpy (dest, map->l_tls_initimage, map->l_tls_initimage_size),
'\0', map->l_tls_blocksize - map->l_tls_initimage_size);
attribute_hidden
__pthread_init_static_tls (struct link_map *map)
{
- lll_lock (stack_cache_lock);
+ lll_lock (stack_cache_lock, LLL_PRIVATE);
/* Iterate over the list with system-allocated threads first. */
list_t *runp;
list_for_each (runp, &__stack_user)
init_one_static_tls (list_entry (runp, struct pthread, list), map);
- lll_unlock (stack_cache_lock);
+ lll_unlock (stack_cache_lock, LLL_PRIVATE);
}
attribute_hidden
__wait_lookup_done (void)
{
- lll_lock (stack_cache_lock);
+ lll_lock (stack_cache_lock, LLL_PRIVATE);
struct pthread *self = THREAD_SELF;
continue;
do
- lll_futex_wait (gscope_flagp, THREAD_GSCOPE_FLAG_WAIT);
+ futex_wait_simple ((unsigned int *) gscope_flagp,
+ THREAD_GSCOPE_FLAG_WAIT, FUTEX_PRIVATE);
while (*gscope_flagp == THREAD_GSCOPE_FLAG_WAIT);
}
continue;
do
- lll_futex_wait (gscope_flagp, THREAD_GSCOPE_FLAG_WAIT);
+ futex_wait_simple ((unsigned int *) gscope_flagp,
+ THREAD_GSCOPE_FLAG_WAIT, FUTEX_PRIVATE);
while (*gscope_flagp == THREAD_GSCOPE_FLAG_WAIT);
}
- lll_unlock (stack_cache_lock);
+ lll_unlock (stack_cache_lock, LLL_PRIVATE);
}
projects / thirdparty / glibc.git / blobdiff