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/*
* Manuel Novoa III Feb 2001
* Erik Andersen 2002-2004
*
* __uClibc_main is the routine to be called by all the arch-specific
* versions of crt0.S in uClibc.
*
* It is meant to handle any special initialization needed by the library
* such as setting the global variable(s) __environ (environ) and
* initializing the stdio package. Using weak symbols, the latter is
* avoided in the static library case.
*/
#define _ERRNO_H
#include <features.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <elf.h>
#ifdef __UCLIBC_PROPOLICE__
extern void __guard_setup(void);
#endif
/*
* Prototypes.
*/
extern int main(int argc, char **argv, char **envp);
extern void weak_function _stdio_init(void);
extern int *weak_const_function __errno_location(void);
extern int *weak_const_function __h_errno_location(void);
#ifdef __UCLIBC_HAS_LOCALE__
extern void weak_function _locale_init(void);
#endif
#ifdef __UCLIBC_HAS_THREADS__
extern void weak_function __pthread_initialize_minimal(void);
#endif
/*
* Declare the __environ global variable and create a weak alias environ.
* Note: Apparently we must initialize __environ to ensure that the weak
* environ symbol is also included.
*/
extern int _dl_secure;
extern size_t _dl_pagesize;
char **__environ = 0;
const char *__progname = 0;
weak_alias(__environ, environ);
/* __uClibc_init completely initialize uClibc so it is ready to use.
*
* On ELF systems (with a dynamic loader) this function must be called
* from the dynamic loader (see TIS and ELF Specification), so that
* constructors of shared libraries (which depend on libc) can use all
* the libc code without restriction. For this we link the shared
* version of the uClibc with -init __uClibc_init so DT_INIT for
* uClibc is the address of __uClibc_init
*
* In all other cases we call it from the main stub
* __uClibc_start_main.
*/
void __uClibc_init(void)
{
static int been_there_done_that = 0;
if (been_there_done_that)
return;
been_there_done_that++;
#ifdef __UCLIBC_HAS_THREADS__
/* Before we start initialzing uClibc we have to call
* __pthread_initialize_minimal so we can use pthread_locks
* whenever they are needed.
*/
if (likely(__pthread_initialize_minimal!=NULL))
__pthread_initialize_minimal();
#endif
#if 0
/* Some security at this point. Prevent starting a SUID binary
* where the standard file descriptors are not opened. We have
* to do this only for statically linked applications since
* otherwise the dynamic loader did the work already. */
if (unlikely (__libc_enable_secure!=NULL))
__libc_check_standard_fds ();
#endif
#ifdef __UCLIBC_HAS_LOCALE__
/* Initialize the global locale structure. */
if (likely(_locale_init!=NULL))
_locale_init();
#endif
/*
* Initialize stdio here. In the static library case, this will
* be bypassed if not needed because of the weak alias above.
*/
if (likely(_stdio_init != NULL))
_stdio_init();
}
#ifdef __UCLIBC_CTOR_DTOR__
void (*__app_fini)(void) = NULL;
#endif
/* __uClibc_start_main is the new main stub for uClibc. This function is
* called from crt0 (version 0.9.16 or newer), after ALL shared libraries
* are initialized, just before we call the application's main function.
*/
void __attribute__ ((__noreturn__))
__uClibc_start_main(int argc, char **argv, char **envp,
void (*app_init)(void), void (*app_fini)(void))
{
unsigned long *aux_dat;
Elf32_auxv_t auxvt[AT_EGID + 1];
/* Pull stuff from the ELF header when possible */
aux_dat = (unsigned long*)envp;
while (*aux_dat) {
aux_dat++;
}
aux_dat++;
while (*aux_dat) {
Elf32_auxv_t *auxv_entry = (Elf32_auxv_t *) aux_dat;
if (auxv_entry->a_type <= AT_EGID) {
memcpy(&(auxvt[auxv_entry->a_type]), auxv_entry, sizeof(Elf32_auxv_t));
}
aux_dat += 2;
}
_dl_pagesize = (auxvt[AT_PAGESZ].a_un.a_val)? auxvt[AT_PAGESZ].a_un.a_val : 4096;
/* If we are dynamically linked the shared lib loader already
* did this for us. But if we are statically linked, we need
* to do this for ourselves. */
if (__environ==NULL) {
/* Statically linked. */
__environ = envp;
}
/* We need to initialize uClibc. If we are dynamically linked this
* may have already been completed by the shared lib loader. We call
* __uClibc_init() regardless, to be sure the right thing happens. */
__uClibc_init();
__progname = *argv;
#ifdef __UCLIBC_CTOR_DTOR__
/* Arrange for the application's dtors to run before we exit. */
__app_fini = app_fini;
/* Run all the application's ctors now. */
if (app_init!=NULL) {
app_init();
}
#endif
#ifdef __UCLIBC_PROPOLICE__
__guard_setup ();
#endif
/* Note: It is possible that any initialization done above could
* have resulted in errno being set nonzero, so set it to 0 before
* we call main.
*/
if (likely(__errno_location!=NULL))
*(__errno_location()) = 0;
/* Set h_errno to 0 as well */
if (likely(__h_errno_location!=NULL))
*(__h_errno_location()) = 0;
/*
* Finally, invoke application's main and then exit.
*/
exit(main(argc, argv, envp));
}
/* __uClibc_main is the old main stub of the uClibc. This
* function is called from crt0 (uClibc 0.9.15 and older) after
* ALL shared libraries are initialized, and just before we call
* the application's main() function.
*
* Attention: This stub does not call the .init/.fini sections of
* the application. If you need this, please fix your uClibc port
* so that __uClibc_start_main is called by your crt0.S with
* _init and _fini properly set.
*/
void __attribute__ ((__noreturn__))
__uClibc_main(int argc, char **argv, char ** envp)
{
__uClibc_start_main(argc, argv, envp, NULL, NULL);
}
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