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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 crt1.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>
#include <link.h>
#include <bits/uClibc_page.h>
#include <paths.h>
#include <unistd.h>
#include <asm/errno.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/sysmacros.h>
#ifdef __UCLIBC_HAS_SSP__
extern void __guard_setup(void);
#endif
/*
* Prototypes.
*/
extern void *__libc_stack_end;
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.
*/
char **__environ = 0;
weak_alias(__environ, environ);
size_t __pagesize = 0;
const char *__progname = 0;
#ifndef O_NOFOLLOW
# define O_NOFOLLOW 0
#endif
extern int __libc_fcntl(int fd, int cmd, ...);
extern int __libc_open(const char *file, int flags, ...);
static void __check_one_fd(int fd, int mode)
{
/* Check if the specified fd is already open */
if (unlikely(__libc_fcntl(fd, F_GETFD)==-1 && *(__errno_location())==EBADF))
{
/* The descriptor is probably not open, so try to use /dev/null */
struct stat st;
int nullfd = __libc_open(_PATH_DEVNULL, mode);
/* /dev/null is major=1 minor=3. Make absolutely certain
* that is in fact the device that we have opened and not
* some other wierd file... */
if ( (nullfd!=fd) || fstat(fd, &st) || !S_ISCHR(st.st_mode) ||
(st.st_rdev != makedev(1, 3)))
{
/* Somebody is trying some trickery here... */
while (1) {
abort();
}
}
}
}
static int __check_suid(void)
{
uid_t uid, euid;
gid_t gid, egid;
uid = getuid();
euid = geteuid();
gid = getgid();
egid = getegid();
if(uid == euid && gid == egid) {
return 0;
}
return 1;
}
/* __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_main.
*/
void __uClibc_init(void)
{
static int been_there_done_that = 0;
if (been_there_done_that)
return;
been_there_done_that++;
/* Setup an initial value. This may not be perfect, but is
* better than malloc using __pagesize=0 for atexit, ctors, etc. */
__pagesize = PAGE_SIZE;
#ifdef __UCLIBC_HAS_THREADS__
/* Before we start initializing 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
#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 attribute_hidden (*__app_fini)(void) = NULL;
#endif
void attribute_hidden (*__rtld_fini)(void) = NULL;
/* __uClibc_main is the new main stub for uClibc. This function is
* called from crt1 (version 0.9.28 or newer), after ALL shared libraries
* are initialized, just before we call the application's main function.
*/
void __attribute__ ((__noreturn__))
__uClibc_main(int (*main)(int, char **, char **), int argc,
char **argv, void (*app_init)(void), void (*app_fini)(void),
void (*rtld_fini)(void), void *stack_end)
{
#ifdef __ARCH_HAS_MMU__
unsigned long *aux_dat;
ElfW(auxv_t) auxvt[AT_EGID + 1];
#endif
__libc_stack_end = stack_end;
/* 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();
__rtld_fini = rtld_fini;
/* The environment begins right after argv. */
__environ = &argv[argc + 1];
/* If the first thing after argv is the arguments
* the the environment is empty. */
if ((char *) __environ == *argv) {
/* Make __environ point to the NULL at argv[argc] */
__environ = &argv[argc];
}
/* Pull stuff from the ELF header when possible */
#ifdef __ARCH_HAS_MMU__
aux_dat = (unsigned long*)__environ;
while (*aux_dat) {
aux_dat++;
}
aux_dat++;
while (*aux_dat) {
ElfW(auxv_t) *auxv_entry = (ElfW(auxv_t) *) aux_dat;
if (auxv_entry->a_type <= AT_EGID) {
memcpy(&(auxvt[auxv_entry->a_type]), auxv_entry, sizeof(ElfW(auxv_t)));
}
aux_dat += 2;
}
/* Make certain getpagesize() gives the correct answer */
__pagesize = (auxvt[AT_PAGESZ].a_un.a_val)? auxvt[AT_PAGESZ].a_un.a_val : PAGE_SIZE;
/* Prevent starting SUID binaries where the stdin. stdout, and
* stderr file descriptors are not already opened. */
if ((auxvt[AT_UID].a_un.a_val==-1 && __check_suid()) ||
(auxvt[AT_UID].a_un.a_val != -1 &&
(auxvt[AT_UID].a_un.a_val != auxvt[AT_EUID].a_un.a_val ||
auxvt[AT_GID].a_un.a_val != auxvt[AT_EGID].a_un.a_val)))
{
__check_one_fd (STDIN_FILENO, O_RDONLY | O_NOFOLLOW);
__check_one_fd (STDOUT_FILENO, O_RDWR | O_NOFOLLOW);
__check_one_fd (STDERR_FILENO, O_RDWR | O_NOFOLLOW);
}
#endif
__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_HAS_SSP__
__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, __environ));
}
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