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Mutex in dynamic linker

* libguile/dynl.c (scm_dynamic_link, scm_dynamic_unlink)
  (scm_dynamic_pointer): Use a mutex to provide thread-safety.
This commit is contained in:
Andy Wingo 2016-11-01 23:13:17 +01:00
parent 399379bf25
commit 2e2396d28c

View file

@ -69,14 +69,8 @@ maybe_drag_in_eprintf ()
/*
From the libtool manual: "Note that libltdl is not threadsafe,
i.e. a multithreaded application has to use a mutex for libltdl.".
Guile does not currently support pre-emptive threads, so there is no
mutex. Previously SCM_CRITICAL_SECTION_START and
SCM_CRITICAL_SECTION_END were used: they are mentioned here in case
somebody is grepping for thread problems ;)
*/
/* njrev: not threadsafe, protection needed as described above */
static scm_i_pthread_mutex_t ltdl_lock = SCM_I_PTHREAD_MUTEX_INITIALIZER;
/* LT_PATH_SEP-separated extension library search path, searched last */
static char *system_extensions_path;
@ -259,6 +253,7 @@ SCM_DEFINE (scm_dynamic_link, "dynamic-link", 0, 1, 0,
char *file;
scm_dynwind_begin (0);
scm_dynwind_pthread_mutex_lock (&ltdl_lock);
if (SCM_UNBNDP (filename))
file = NULL;
@ -301,13 +296,18 @@ SCM_DEFINE (scm_dynamic_unlink, "dynamic-unlink", 1, 0, 0,
{
/*fixme* GC-problem */
SCM_VALIDATE_SMOB (SCM_ARG1, dobj, dynamic_obj);
scm_dynwind_begin (0);
scm_dynwind_pthread_mutex_lock (&ltdl_lock);
if (DYNL_HANDLE (dobj) == NULL) {
SCM_MISC_ERROR ("Already unlinked: ~S", scm_list_1 (dobj));
} else {
sysdep_dynl_unlink (DYNL_HANDLE (dobj), FUNC_NAME);
SET_DYNL_HANDLE (dobj, NULL);
return SCM_UNSPECIFIED;
}
scm_dynwind_end ();
return SCM_UNSPECIFIED;
}
#undef FUNC_NAME
@ -335,6 +335,7 @@ SCM_DEFINE (scm_dynamic_pointer, "dynamic-pointer", 2, 0, 0,
char *chars;
scm_dynwind_begin (0);
scm_dynwind_pthread_mutex_lock (&ltdl_lock);
chars = scm_to_locale_string (name);
scm_dynwind_free (chars);
val = sysdep_dynl_value (chars, DYNL_HANDLE (dobj), FUNC_NAME);