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Message-Id: <20161031172658.970-1-timo.teras@iki.fi>
Date: Mon, 31 Oct 2016 19:26:58 +0200
From: Timo Teräs <timo.teras@....fi>
To: musl@...ts.openwall.com
Cc: Timo Teräs <timo.teras@....fi>
Subject: [PATCH] add support for pthread_{get,set}attr_default_np GNU extension
While generally this is a bad API, it is the only existing API to
affect c++ (std::thread) and c11 (thrd_create) thread stack size.
This patch allows applications only to increate stack and guard
page sizes.
---
include/pthread.h | 2 ++
src/thread/pthread_create.c | 7 +++++++
src/thread/pthread_setattr_default_np.c | 31 +++++++++++++++++++++++++++++++
3 files changed, 40 insertions(+)
create mode 100644 src/thread/pthread_setattr_default_np.c
diff --git a/include/pthread.h b/include/pthread.h
index 94ef919..bba9587 100644
--- a/include/pthread.h
+++ b/include/pthread.h
@@ -215,6 +215,8 @@ int pthread_getaffinity_np(pthread_t, size_t, struct cpu_set_t *);
int pthread_setaffinity_np(pthread_t, size_t, const struct cpu_set_t *);
int pthread_getattr_np(pthread_t, pthread_attr_t *);
int pthread_setname_np(pthread_t, const char *);
+int pthread_getattr_default_np(pthread_attr_t *);
+int pthread_setattr_default_np(const pthread_attr_t *);
int pthread_tryjoin_np(pthread_t, void **);
int pthread_timedjoin_np(pthread_t, void **, const struct timespec *);
#endif
diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c
index 9f6b98e..28cf6d4 100644
--- a/src/thread/pthread_create.c
+++ b/src/thread/pthread_create.c
@@ -163,6 +163,8 @@ static void *dummy_tsd[1] = { 0 };
weak_alias(dummy_tsd, __pthread_tsd_main);
volatile int __block_new_threads = 0;
+size_t __default_stacksize = 0;
+size_t __default_guardsize = 0;
static FILE *volatile dummy_file = 0;
weak_alias(dummy_file, __stdin_used);
@@ -204,6 +206,11 @@ int __pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict att
if (attrp && !c11) attr = *attrp;
__acquire_ptc();
+ if (!attrp || c11) {
+ attr._a_stacksize = __default_stacksize;
+ attr._a_guardsize = __default_guardsize;
+ }
+
if (__block_new_threads) __wait(&__block_new_threads, 0, 1, 1);
if (attr._a_stackaddr) {
diff --git a/src/thread/pthread_setattr_default_np.c b/src/thread/pthread_setattr_default_np.c
new file mode 100644
index 0000000..21cd0f3
--- /dev/null
+++ b/src/thread/pthread_setattr_default_np.c
@@ -0,0 +1,31 @@
+#include "pthread_impl.h"
+
+extern size_t __default_stacksize;
+extern size_t __default_guardsize;
+
+int pthread_setattr_default_np(const pthread_attr_t *attrp)
+{
+ if (attrp->_a_stackaddr || attrp->_a_detach ||
+ attrp->_a_sched || attrp->_a_policy || attrp->_a_prio)
+ return EINVAL;
+
+ __inhibit_ptc();
+ if (DEFAULT_STACK_SIZE+attrp->_a_stacksize >= DEFAULT_STACK_SIZE+__default_stacksize)
+ __default_stacksize = attrp->_a_stacksize;
+ if (DEFAULT_GUARD_SIZE+attrp->_a_guardsize >= DEFAULT_GUARD_SIZE+__default_guardsize)
+ __default_guardsize = attrp->_a_guardsize;
+ __release_ptc();
+
+ return 0;
+}
+
+int pthread_getattr_default_np(pthread_attr_t *attrp)
+{
+ __acquire_ptc();
+ *attrp = (pthread_attr_t) {
+ ._a_stacksize = __default_stacksize,
+ ._a_guardsize = __default_guardsize,
+ };
+ __release_ptc();
+ return 0;
+}
--
2.10.1
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