limit the configurable default stack/guard size for threads

limit to 8MB/1MB, repectively. since the defaults cannot be reduced
once increased, excessively large settings would lead to an
unrecoverably broken state. this change is in preparation to allow
defaults to be increased via program headers at the linker level.

creation of threads that really need larger sizes needs to be done
with an explicit attribute.

diff --git a/src/internal/pthread_impl.h b/src/internal/pthread_impl.h
index 26e6e1dfefb33b649901b880d448f3eec49c6a09..e73a251f8f0000b1b2e35458f9da779884aec424 100644 (file)
--- a/src/internal/pthread_impl.h
+++ b/src/internal/pthread_impl.h
@@ -182,12 +182,15 @@ hidden void __acquire_ptc(void);
 hidden void __release_ptc(void);
 hidden void __inhibit_ptc(void);
 
-extern hidden size_t __default_stacksize;
-extern hidden size_t __default_guardsize;
+extern hidden unsigned __default_stacksize;
+extern hidden unsigned __default_guardsize;
 
 #define DEFAULT_STACK_SIZE 81920
 #define DEFAULT_GUARD_SIZE 4096
 
+#define DEFAULT_STACK_MAX (8<<20)
+#define DEFAULT_GUARD_MAX (1<<20)
+
 #define __ATTRP_C11_THREAD ((void*)(uintptr_t)-1)
 
 #endif

diff --git a/src/thread/default_attr.c b/src/thread/default_attr.c
index 46fe98ee5ce29449c5fabc43a113c5f689970291..dce9640964c23ffc0e14da4ae7a56f7a2a418515 100644 (file)
--- a/src/thread/default_attr.c
+++ b/src/thread/default_attr.c
@@ -1,4 +1,4 @@
 #include "pthread_impl.h"
 
-size_t __default_stacksize = DEFAULT_STACK_SIZE;
-size_t __default_guardsize = DEFAULT_GUARD_SIZE;
+unsigned __default_stacksize = DEFAULT_STACK_SIZE;
+unsigned __default_guardsize = DEFAULT_GUARD_SIZE;

diff --git a/src/thread/pthread_setattr_default_np.c b/src/thread/pthread_setattr_default_np.c
index 256f06850e73cf6936af2523cb15f56444612190..58486220e026c778988b68398191c7ec177d0f88 100644 (file)
--- a/src/thread/pthread_setattr_default_np.c
+++ b/src/thread/pthread_setattr_default_np.c
@@ -2,6 +2,9 @@
 #include "pthread_impl.h"
 #include <string.h>
 
+#define MIN(a,b) ((a)<(b) ? (a) : (b))
+#define MAX(a,b) ((a)>(b) ? (a) : (b))
+
 int pthread_setattr_default_np(const pthread_attr_t *attrp)
 {
        /* Reject anything in the attr object other than stack/guard size. */
@@ -11,11 +14,12 @@ int pthread_setattr_default_np(const pthread_attr_t *attrp)
        if (memcmp(&tmp, &zero, sizeof tmp))
                return EINVAL;
 
+       unsigned stack = MIN(attrp->_a_stacksize, DEFAULT_STACK_MAX);
+       unsigned guard = MIN(attrp->_a_guardsize, DEFAULT_GUARD_MAX);
+
        __inhibit_ptc();
-       if (attrp->_a_stacksize >= __default_stacksize)
-               __default_stacksize = attrp->_a_stacksize;
-       if (attrp->_a_guardsize >= __default_guardsize)
-               __default_guardsize = attrp->_a_guardsize;
+       __default_stacksize = MAX(__default_stacksize, stack);
+       __default_guardsize = MAX(__default_guardsize, guard);
        __release_ptc();
 
        return 0;