Fix the C library runtime initialization order.

This allows libc.so to run the C runtime initializer as soon as the
dynamic linker loads the shared library, i.e. before any other initializers
(e.g. static C++ constructors in other shared libraries the executable depends
on).

This also removes the bug where the initializers from the executable itself
were run twice: once by the dynamic linker, and another time by __libc_init
as defined by libc_init_dynamic.c
This commit is contained in:
David 'Digit' Turner
2009-07-18 01:11:10 +02:00
parent ef0bd18570
commit b56b5659b3
4 changed files with 117 additions and 102 deletions

View File

@@ -28,24 +28,15 @@
/*
* 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.
* The program startup function __libc_init() defined here is
* used for static executables only (i.e. those that don't depend
* on shared libraries). It is called from arch-$ARCH/bionic/crtbegin_static.S
* which is directly invoked by the kernel when the program is launched.
*
* 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
* The 'structors' parameter contains pointers to various initializer
* arrays that must be run before the program's 'main' routine is launched.
*/
/*
* Several Linux ABIs don't pass the onexit pointer, and the ones that
* do never use it. Therefore, unless USE_ONEXIT is defined, we just
* ignore the onexit pointer.
*/
/* #define USE_ONEXIT */
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
@@ -58,19 +49,41 @@
#include <bionic_tls.h>
#include <errno.h>
static void call_array(void(**list)())
{
// First element is -1, list is null-terminated
while (*++list) {
(*list)();
}
}
__noreturn void __libc_init(uintptr_t *elfdata,
void (*onexit)(void),
int (*slingshot)(int, char**, char**),
structors_array_t const * const structors)
{
/*
* To enable malloc checks for statically linked programs, add
* "WITH_MALLOC_CHECK_LIBC_A := true" in device/buildspec.mk
*/
#ifdef MALLOC_LEAK_CHECK
extern void malloc_debug_init();
__libc_init_common(elfdata, onexit, slingshot, structors, malloc_debug_init);
#else
__libc_init_common(elfdata, onexit, slingshot, structors, NULL);
#endif
int argc;
char **argv, **envp;
/* Initialize the C runtime environment */
__libc_init_common(elfdata);
/* Several Linux ABIs don't pass the onexit pointer, and the ones that
* do never use it. Therefore, we ignore it.
*/
/* pre-init array. */
call_array(structors->preinit_array);
/* .ctors section initializers, for non-arm-eabi ABIs */
call_array(structors->ctors_array);
// call static constructors
call_array(structors->init_array);
argc = (int) *elfdata;
argv = (char**)(elfdata + 1);
envp = argv + argc + 1;
exit(slingshot(argc, argv, envp));
}