diff options
authorRich Felker <>2012-11-30 17:56:23 -0500
committerRich Felker <>2012-11-30 17:56:23 -0500
commita7936f61b23100ac32f51776c5b3e52452c7598c (patch)
parent1c322f2f0a9173a3ae8c8bfa12d5d8e92fb5d0ab (diff)
fix ordering of shared library ctors with respect to libc init
previously, shared library constructors were being called before important internal things like the environment (extern char **environ) and hwcap flags (needed for sjlj to work right with float on arm) were initialized in __libc_start_main. rather than trying to have to dynamic linker make sure this stuff all gets initialized right, I've opted to just defer calling shared library constructors until after the main program's entry point is reached. this also fixes the order of ctors to be the exact reverse of dtors, which is a desirable property and possibly even mandated by some languages. the main practical effect of this change is that shared libraries calling getenv from ctors will no longer fail.
2 files changed, 11 insertions, 3 deletions
diff --git a/src/env/__libc_start_main.c b/src/env/__libc_start_main.c
index ee10b0de..04a454e8 100644
--- a/src/env/__libc_start_main.c
+++ b/src/env/__libc_start_main.c
@@ -3,6 +3,7 @@
void __init_tls(size_t *);
void __init_security(size_t *);
+void __init_ldso_ctors(void);
#define AUX_CNT 38
@@ -37,6 +38,10 @@ int __libc_start_main(
/* Execute constructors (static) linked into the application */
if (init) init(argc, argv, envp);
+#ifdef SHARED
+ __init_ldso_ctors();
/* Pass control to to application */
exit(main(argc, argv, envp));
return 0;
diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c
index c436b88f..d564b8f2 100644
--- a/src/ldso/dynlink.c
+++ b/src/ldso/dynlink.c
@@ -999,13 +999,16 @@ void *__dynlink(int argc, char **argv)
if (ssp_used) __init_ssp((void *)aux[AT_RANDOM]);
- atexit(do_fini);
- do_init_fini(tail);
errno = 0;
return (void *)aux[AT_ENTRY];
+void __init_ldso_ctors(void)
+ atexit(do_fini);
+ do_init_fini(tail);
void *dlopen(const char *file, int mode)
struct dso *volatile p, *orig_tail, *next;