diff options
Diffstat (limited to 'REORG.TODO/csu/libc-start.c')
| -rw-r--r-- | REORG.TODO/csu/libc-start.c | 336 |
1 files changed, 336 insertions, 0 deletions
diff --git a/REORG.TODO/csu/libc-start.c b/REORG.TODO/csu/libc-start.c new file mode 100644 index 0000000000..c2dd1593eb --- /dev/null +++ b/REORG.TODO/csu/libc-start.c @@ -0,0 +1,336 @@ +/* Copyright (C) 1998-2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <assert.h> +#include <stdlib.h> +#include <stdio.h> +#include <unistd.h> +#include <ldsodefs.h> +#include <exit-thread.h> +#include <libc-internal.h> + +#include <elf/dl-tunables.h> + +extern void __libc_init_first (int argc, char **argv, char **envp); + +extern int __libc_multiple_libcs; + +#include <tls.h> +#ifndef SHARED +# 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. */ +uintptr_t __stack_chk_guard attribute_relro; +# endif +# ifndef THREAD_SET_POINTER_GUARD +/* Only exported for architectures that don't store the pointer guard + value in thread local area. */ +uintptr_t __pointer_chk_guard_local + attribute_relro attribute_hidden __attribute__ ((nocommon)); +# endif +#endif + +#ifdef HAVE_PTR_NTHREADS +/* We need atomic operations. */ +# include <atomic.h> +#endif + + +#ifndef SHARED +# include <link.h> +# include <dl-irel.h> + +# ifdef ELF_MACHINE_IRELA +# define IREL_T ElfW(Rela) +# define IPLT_START __rela_iplt_start +# define IPLT_END __rela_iplt_end +# define IREL elf_irela +# elif defined ELF_MACHINE_IREL +# define IREL_T ElfW(Rel) +# define IPLT_START __rel_iplt_start +# define IPLT_END __rel_iplt_end +# define IREL elf_irel +# endif + +static void +apply_irel (void) +{ +# ifdef IREL + /* We use weak references for these so that we'll still work with a linker + that doesn't define them. Such a linker doesn't support IFUNC at all + and so uses won't work, but a statically-linked program that doesn't + use any IFUNC symbols won't have a problem. */ + extern const IREL_T IPLT_START[] __attribute__ ((weak)); + extern const IREL_T IPLT_END[] __attribute__ ((weak)); + for (const IREL_T *ipltent = IPLT_START; ipltent < IPLT_END; ++ipltent) + IREL (ipltent); +# endif +} +#endif + + +#ifdef LIBC_START_MAIN +# ifdef LIBC_START_DISABLE_INLINE +# define STATIC static +# else +# define STATIC static inline __attribute__ ((always_inline)) +# endif +#else +# define STATIC +# define LIBC_START_MAIN __libc_start_main +#endif + +#ifdef MAIN_AUXVEC_ARG +/* main gets passed a pointer to the auxiliary. */ +# define MAIN_AUXVEC_DECL , void * +# define MAIN_AUXVEC_PARAM , auxvec +#else +# define MAIN_AUXVEC_DECL +# define MAIN_AUXVEC_PARAM +#endif + +#ifndef ARCH_INIT_CPU_FEATURES +# define ARCH_INIT_CPU_FEATURES() +#endif + +STATIC int LIBC_START_MAIN (int (*main) (int, char **, char ** + MAIN_AUXVEC_DECL), + int argc, + char **argv, +#ifdef LIBC_START_MAIN_AUXVEC_ARG + ElfW(auxv_t) *auxvec, +#endif + __typeof (main) init, + void (*fini) (void), + void (*rtld_fini) (void), + void *stack_end) + __attribute__ ((noreturn)); + + +/* Note: the fini parameter is ignored here for shared library. It + is registered with __cxa_atexit. This had the disadvantage that + finalizers were called in more than one place. */ +STATIC int +LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL), + int argc, char **argv, +#ifdef LIBC_START_MAIN_AUXVEC_ARG + ElfW(auxv_t) *auxvec, +#endif + __typeof (main) init, + void (*fini) (void), + void (*rtld_fini) (void), void *stack_end) +{ + /* Result of the 'main' function. */ + int result; + + __libc_multiple_libcs = &_dl_starting_up && !_dl_starting_up; + +#ifndef SHARED + char **ev = &argv[argc + 1]; + + __environ = ev; + + /* Store the lowest stack address. This is done in ld.so if this is + the code for the DSO. */ + __libc_stack_end = stack_end; + +# ifdef HAVE_AUX_VECTOR + /* First process the auxiliary vector since we need to find the + program header to locate an eventually present PT_TLS entry. */ +# ifndef LIBC_START_MAIN_AUXVEC_ARG + ElfW(auxv_t) *auxvec; + { + char **evp = ev; + while (*evp++ != NULL) + ; + auxvec = (ElfW(auxv_t) *) evp; + } +# endif + _dl_aux_init (auxvec); + if (GL(dl_phdr) == NULL) +# endif + { + /* Starting from binutils-2.23, the linker will define the + magic symbol __ehdr_start to point to our own ELF header + if it is visible in a segment that also includes the phdrs. + So we can set up _dl_phdr and _dl_phnum even without any + information from auxv. */ + + extern const ElfW(Ehdr) __ehdr_start + __attribute__ ((weak, visibility ("hidden"))); + if (&__ehdr_start != NULL) + { + assert (__ehdr_start.e_phentsize == sizeof *GL(dl_phdr)); + GL(dl_phdr) = (const void *) &__ehdr_start + __ehdr_start.e_phoff; + GL(dl_phnum) = __ehdr_start.e_phnum; + } + } + + /* Initialize very early so that tunables can use it. */ + __libc_init_secure (); + + __tunables_init (__environ); + + ARCH_INIT_CPU_FEATURES (); + + /* Perform IREL{,A} relocations. */ + apply_irel (); + + /* The stack guard goes into the TCB, so initialize it early. */ + __libc_setup_tls (); + + /* Set up the stack checker's canary. */ + uintptr_t stack_chk_guard = _dl_setup_stack_chk_guard (_dl_random); +# ifdef THREAD_SET_STACK_GUARD + THREAD_SET_STACK_GUARD (stack_chk_guard); +# else + __stack_chk_guard = stack_chk_guard; +# endif + +# ifdef DL_SYSDEP_OSCHECK + if (!__libc_multiple_libcs) + { + /* This needs to run to initiliaze _dl_osversion before TLS + setup might check it. */ + DL_SYSDEP_OSCHECK (__libc_fatal); + } +# endif + + /* Initialize libpthread if linked in. */ + if (__pthread_initialize_minimal != NULL) + __pthread_initialize_minimal (); + + /* Set up the pointer guard value. */ + uintptr_t pointer_chk_guard = _dl_setup_pointer_guard (_dl_random, + stack_chk_guard); +# ifdef THREAD_SET_POINTER_GUARD + THREAD_SET_POINTER_GUARD (pointer_chk_guard); +# else + __pointer_chk_guard_local = pointer_chk_guard; +# endif + +#endif + + /* Register the destructor of the dynamic linker if there is any. */ + if (__glibc_likely (rtld_fini != NULL)) + __cxa_atexit ((void (*) (void *)) rtld_fini, NULL, NULL); + +#ifndef SHARED + /* Call the initializer of the libc. This is only needed here if we + are compiling for the static library in which case we haven't + run the constructors in `_dl_start_user'. */ + __libc_init_first (argc, argv, __environ); + + /* Register the destructor of the program, if any. */ + if (fini) + __cxa_atexit ((void (*) (void *)) fini, NULL, NULL); + + /* 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 (__builtin_expect (__libc_enable_secure, 0)) + __libc_check_standard_fds (); +#endif + + /* Call the initializer of the program, if any. */ +#ifdef SHARED + if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS, 0)) + GLRO(dl_debug_printf) ("\ninitialize program: %s\n\n", argv[0]); +#endif + if (init) + (*init) (argc, argv, __environ MAIN_AUXVEC_PARAM); + +#ifdef SHARED + /* Auditing checkpoint: we have a new object. */ + if (__glibc_unlikely (GLRO(dl_naudit) > 0)) + { + struct audit_ifaces *afct = GLRO(dl_audit); + struct link_map *head = GL(dl_ns)[LM_ID_BASE]._ns_loaded; + for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt) + { + if (afct->preinit != NULL) + afct->preinit (&head->l_audit[cnt].cookie); + + afct = afct->next; + } + } +#endif + +#ifdef SHARED + if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS)) + GLRO(dl_debug_printf) ("\ntransferring control: %s\n\n", argv[0]); +#endif + +#ifndef SHARED + _dl_debug_initialize (0, LM_ID_BASE); +#endif +#ifdef HAVE_CLEANUP_JMP_BUF + /* Memory for the cancellation buffer. */ + struct pthread_unwind_buf unwind_buf; + + int not_first_call; + not_first_call = setjmp ((struct __jmp_buf_tag *) unwind_buf.cancel_jmp_buf); + if (__glibc_likely (! not_first_call)) + { + struct pthread *self = THREAD_SELF; + + /* Store old info. */ + unwind_buf.priv.data.prev = THREAD_GETMEM (self, cleanup_jmp_buf); + unwind_buf.priv.data.cleanup = THREAD_GETMEM (self, cleanup); + + /* Store the new cleanup handler info. */ + THREAD_SETMEM (self, cleanup_jmp_buf, &unwind_buf); + + /* Run the program. */ + result = main (argc, argv, __environ MAIN_AUXVEC_PARAM); + } + else + { + /* Remove the thread-local data. */ +# ifdef SHARED + PTHFCT_CALL (ptr__nptl_deallocate_tsd, ()); +# else + extern void __nptl_deallocate_tsd (void) __attribute ((weak)); + __nptl_deallocate_tsd (); +# endif + + /* One less thread. Decrement the counter. If it is zero we + terminate the entire process. */ + result = 0; +# ifdef SHARED + unsigned int *ptr = __libc_pthread_functions.ptr_nthreads; +# ifdef PTR_DEMANGLE + PTR_DEMANGLE (ptr); +# endif +# else + extern unsigned int __nptl_nthreads __attribute ((weak)); + unsigned int *const ptr = &__nptl_nthreads; +# endif + + if (! atomic_decrement_and_test (ptr)) + /* Not much left to do but to exit the thread, not the process. */ + __exit_thread (); + } +#else + /* Nothing fancy, just call the function. */ + result = main (argc, argv, __environ MAIN_AUXVEC_PARAM); +#endif + + exit (result); +} |