Fix the C library initialization to avoid calling static C++ constructors twice.
The problem was due to the fact that, in the case of dynamic executables,
the dynamic linker calls the DT_PREINIT_ARRAY, DT_INIT and DT_INIT_ARRAY
constructors when loading shared libraries and dynamic executables,
*before* calling the executable's entry point (i.e. arch-$ARCH/bionic/crtbegin_dynamic.c)
which in turns call __libc_init() in libc.so, as defined by bionic/libc_init_dynamic.c
The latter did call these constructors array again, mistakenly.
The patch also updates the documentation of many related functions.
Also adds a new section to linker/README.TXT explaining restrictions on
C library usage.
The patch has been tested on a Dream for stability issues with
proprietary blobs:
- H264 decoding works
- Camera + Video recording works
- GPS works
- Sensors work
The tests in system/extra/tests/bionic/libc/common/test_static_cpp_mutex.cpp has been
run and shows the static C++ constructor being called only once.
diff --git a/libc/bionic/libc_init_static.c b/libc/bionic/libc_init_static.c
index ec463f7..d7af640 100644
--- a/libc/bionic/libc_init_static.c
+++ b/libc/bionic/libc_init_static.c
@@ -25,18 +25,30 @@
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
+
/*
* libc_init_static.c
*
- * This function takes the raw data block set up by the ELF loader
- * in the kernel and parses it. It is invoked by crt0.S which makes
- * any necessary adjustments and passes calls this function using
- * the standard C calling convention.
+ * This function is called for static executables, i.e. those that
+ * dont depend on shared libraries and are directly started by the
+ * Linux kernel.
+ *
+ * It takes the raw data block set up by the ELF loader
+ * in the kernel and parses it.
*
* The arguments are:
- * uintptr_t *elfdata -- The ELF loader data block; usually from the stack.
- * Basically a pointer to argc.
- * void (*onexit)(void) -- Function to install into onexit
+ * elfdata -- The ELF loader data block; usually from the stack.
+ * Basically a pointer to argc.
+ *
+ * onexit -- Function to call on exit, can be NULL.
+ *
+ * slingshot -- Address of the program's main function
+ *
+ * structors -- Table of constructor functions arrays that must
+ * be called before the slingshot.
+ *
+ * It is called from the assembly fragment found in
+ * arch-$ARCH/bionic/crtbegin_static.S
*/
/*
@@ -51,18 +63,19 @@
#include <stdlib.h>
#include <stdint.h>
#include <elf.h>
-#include "pthread_internal.h"
-#include "atexit.h"
+#include "bionic_preinit.h"
#include "libc_init_common.h"
-#include <bionic_tls.h>
-#include <errno.h>
-
__noreturn void __libc_init(uintptr_t *elfdata,
void (*onexit)(void),
int (*slingshot)(int, char**, char**),
structors_array_t const * const structors)
{
+ pthread_internal_t thread;
+ void *tls_area[BIONIC_TLS_SLOTS];
+
+ __libc_preinit( &thread, tls_area );
+
/*
* To enable malloc checks for statically linked programs, add
* "WITH_MALLOC_CHECK_LIBC_A := true" in device/buildspec.mk