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/*
* libc_init.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 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
*/
/*
* 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 <stdlib.h>
#include <stdint.h>
#include <klibc/compiler.h>
#include <elf.h>
#include <sys/auxv.h>
#include <klibc/sysconfig.h>
#include "atexit.h"
#if _KLIBC_HAS_ARCHINIT
# include "klibc/archinit.h"
#else
# define __libc_archinit() ((void)0)
#endif
/* This file is included from __static_init.c or __shared_init.c */
#ifndef SHARED
# error "SHARED should be defined to 0 or 1"
#endif
char **environ;
unsigned int __page_size, __page_shift;
struct auxentry {
unsigned long type;
unsigned long v;
};
extern void __libc_init_stdio(void);
unsigned long __auxval[_AUXVAL_MAX];
__noreturn __libc_init(uintptr_t * elfdata, void (*onexit) (void))
{
int argc;
char **argv, **envp, **envend;
struct auxentry *auxentry;
#if SHARED
typedef int (*main_t) (int, char **, char **);
main_t MAIN = NULL;
#else
extern int main(int, char **, char **);
#define MAIN main
#endif
unsigned int page_size = 0, page_shift = 0;
#ifdef USE_ONEXIT
if (onexit) {
static struct atexit at_exit;
at_exit.fctn = (void (*)(int, void *))onexit;
/* at_exit.next = NULL already */
__atexit_list = &at_exit;
}
#else
(void)onexit; /* Ignore this... */
#endif
argc = (int)*elfdata++;
argv = (char **)elfdata;
envp = argv + (argc + 1);
/* The auxillary entry vector is after all the environment vars */
for (envend = envp; *envend; envend++) ;
auxentry = (struct auxentry *)(envend + 1);
while (auxentry->type) {
if (auxentry->type < _AUXVAL_MAX)
__auxval[auxentry->type] = auxentry->v;
auxentry++;
}
#if SHARED
MAIN = (main_t) __auxval[AT_ENTRY];
#endif
__page_size = page_size = __auxval[AT_PAGESZ];
#if __GNUC__ >= 4
/* unsigned int is 32 bits on all our architectures */
page_shift = __builtin_clz(page_size) ^ 31;
#elif defined(__i386__) || defined(__x86_64__)
asm("bsrl %1,%0" : "=r" (page_shift) : "r" (page_size));
#else
while (page_size > 1) {
page_shift++;
page_size >>= 1;
}
#endif
__page_shift = page_shift;
#if _KLIBC_HAS_ARCHINIT
__libc_archinit();
#endif
__libc_init_stdio();
environ = envp;
exit(MAIN(argc, argv, envp));
}
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