/* * Copyright (C) Feb 2001 Manuel Novoa III * Copyright (C) 2000-2005 Erik Andersen <andersen@uclibc.org> * * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball. * * __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 getgid __getgid #define getuid __getuid #define getegid __getegid #define geteuid __geteuid #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> #ifndef SHARED void *__libc_stack_end=NULL; /* probably all the weak_*function stuff below should be in here */ #ifdef __UCLIBC_HAS_SSP__ #include <dl-osinfo.h> #ifndef THREAD_SET_STACK_GUARD /* Only exported for architectures that don't store the stack guard canary * in thread local area. */ #include <stdint.h> /* for gcc-4.1 non-TLS */ uintptr_t __stack_chk_guard attribute_relro; /* for gcc-3.x + Etoh ssp */ strong_alias(__stack_chk_guard,__guard) #endif #endif #endif /* !SHARED */ /* * Prototypes. */ 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, ...); #ifdef __ARCH_HAS_MMU__ 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 = __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; } #endif /* __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 #ifndef SHARED # ifdef __UCLIBC_HAS_SSP__ /* Set up the stack checker's canary. */ uintptr_t stack_chk_guard = _dl_setup_stack_chk_guard(); # ifdef THREAD_SET_STACK_GUARD THREAD_SET_STACK_GUARD (stack_chk_guard); # else __stack_chk_guard = stack_chk_guard; # endif # endif #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 #ifndef SHARED __libc_stack_end = stack_end; #endif __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; } /* 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(); /* 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 /* 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)); }