TLS (GNU/C11 thread-local storage) support for static-linked programs
the design for TLS in dynamic-linked programs is mostly complete too,
but I have not yet implemented it. cost is nonzero but still low for
programs which do not use TLS and/or do not use threads (a few hundred
bytes of new code, plus dependency on memcpy). i believe it can be
made smaller at some point by merging __init_tls and __init_security
into __libc_start_main and avoiding duplicate auxv-parsing code.
at the same time, I've also slightly changed the logic pthread_create
uses to allocate guard pages to ensure that guard pages are not
counted towards commit charge.
diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c
index 960e089..1447e20 100644
--- a/src/ldso/dynlink.c
+++ b/src/ldso/dynlink.c
@@ -17,6 +17,9 @@
#include <pthread.h>
#include <ctype.h>
#include <dlfcn.h>
+#include "pthread_impl.h"
+#include "libc.h"
+#undef libc
static int errflag;
static char errbuf[128];
@@ -788,6 +791,8 @@
debug.state = 0;
_dl_debug_state();
+ /* Stand-in until real TLS support is added to dynamic linker */
+ __libc.tls_size = sizeof(struct pthread) + 4*sizeof(size_t);
if (ssp_used) __init_ssp(auxv);
do_init_fini(tail);
@@ -802,6 +807,11 @@
return (void *)aux[AT_ENTRY];
}
+void *__copy_tls(unsigned char *mem, size_t cnt)
+{
+ return mem;
+}
+
void *dlopen(const char *file, int mode)
{
struct dso *volatile p, *orig_tail = tail, *next;