2 * Copyright (C) 2006 by Steven J. Hill <sjhill@realitydiluted.com>
3 * Copyright (C) 2001 by Manuel Novoa III <mjn3@uclibc.org>
4 * Copyright (C) 2000-2005 Erik Andersen <andersen@uclibc.org>
6 * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
8 * __uClibc_main is the routine to be called by all the arch-specific
9 * versions of crt1.S in uClibc.
11 * It is meant to handle any special initialization needed by the library
12 * such as setting the global variable(s) __environ (environ) and
13 * initializing the stdio package. Using weak symbols, the latter is
14 * avoided in the static library case.
23 #include <bits/uClibc_page.h>
30 #include <sys/sysmacros.h>
31 #ifdef __UCLIBC_HAS_THREADS_NATIVE__
32 #include <pthread-functions.h>
33 #include <not-cancel.h>
36 #ifdef __UCLIBC_HAS_THREADS__
39 #ifdef __UCLIBC_HAS_LOCALE__
44 void *__libc_stack_end = NULL;
46 # ifdef __UCLIBC_HAS_SSP__
47 # include <dl-osinfo.h>
48 static uintptr_t stack_chk_guard;
49 # ifndef THREAD_SET_STACK_GUARD
50 /* Only exported for architectures that don't store the stack guard canary
51 * in thread local area. */
52 /* for gcc-4.1 non-TLS */
53 uintptr_t __stack_chk_guard attribute_relro;
55 /* for gcc-3.x + Etoh ssp */
56 # ifdef __UCLIBC_HAS_SSP_COMPAT__
57 uintptr_t __guard attribute_relro;
62 * Needed to initialize _dl_phdr when statically linked
65 void internal_function _dl_aux_init (ElfW(auxv_t) *av);
67 #ifdef __UCLIBC_HAS_THREADS__
69 * uClibc internal locking requires that we have weak aliases
70 * for dummy functions in case libpthread.a is not linked in.
71 * This needs to be in compilation unit that is pulled always
72 * in or linker will disregard these weaks.
75 static int __pthread_return_0 (pthread_mutex_t *unused) { return 0; }
76 weak_alias (__pthread_return_0, __pthread_mutex_lock)
77 weak_alias (__pthread_return_0, __pthread_mutex_trylock)
78 weak_alias (__pthread_return_0, __pthread_mutex_unlock)
81 __pthread_mutex_init(pthread_mutex_t *mutex, const pthread_mutexattr_t *attr)
87 _pthread_cleanup_push_defer(struct _pthread_cleanup_buffer *__buffer,
88 void (*__routine) (void *), void *__arg)
90 __buffer->__routine = __routine;
91 __buffer->__arg = __arg;
95 _pthread_cleanup_pop_restore(struct _pthread_cleanup_buffer *__buffer,
99 __buffer->__routine(__buffer->__arg);
101 #endif /* __UCLIBC_HAS_THREADS__ */
105 /* Defeat compiler optimization which assumes function addresses are never NULL */
106 static __always_inline int not_null_ptr(const void *p)
110 : "=r" (q) /* output */
111 : "0" (p) /* input */
119 #ifdef __UCLIBC_HAS_THREADS__
120 #if !defined (__UCLIBC_HAS_THREADS_NATIVE__) || defined (SHARED)
121 extern void weak_function __pthread_initialize_minimal(void);
123 extern void __pthread_initialize_minimal(void);
127 /* If __UCLIBC_FORMAT_SHARED_FLAT__, all array initialisation and finalisation
128 * is handled by the routines passed to __uClibc_main(). */
129 #if defined (__UCLIBC_CTOR_DTOR__) && !defined (__UCLIBC_FORMAT_SHARED_FLAT__)
130 extern void _dl_app_init_array(void);
131 extern void _dl_app_fini_array(void);
133 /* These magic symbols are provided by the linker. */
134 extern void (*__preinit_array_start []) (void) attribute_hidden;
135 extern void (*__preinit_array_end []) (void) attribute_hidden;
136 extern void (*__init_array_start []) (void) attribute_hidden;
137 extern void (*__init_array_end []) (void) attribute_hidden;
138 extern void (*__fini_array_start []) (void) attribute_hidden;
139 extern void (*__fini_array_end []) (void) attribute_hidden;
143 attribute_hidden const char *__uclibc_progname = "";
144 #ifdef __UCLIBC_HAS_PROGRAM_INVOCATION_NAME__
145 const char *program_invocation_short_name = "";
146 const char *program_invocation_name = "";
148 #ifdef __UCLIBC_HAS___PROGNAME__
149 weak_alias (program_invocation_short_name, __progname)
150 weak_alias (program_invocation_name, __progname_full)
154 * Declare the __environ global variable and create a weak alias environ.
155 * This must be initialized; we cannot have a weak alias into bss.
157 char **__environ = 0;
158 weak_alias(__environ, environ)
160 /* TODO: don't export __pagesize; we cant now because libpthread uses it */
161 size_t __pagesize = 0;
164 # define O_NOFOLLOW 0
167 #ifndef __ARCH_HAS_NO_LDSO__
168 static void __check_one_fd(int fd, int mode)
170 /* Check if the specified fd is already open */
171 if (fcntl(fd, F_GETFD) == -1)
173 /* The descriptor is probably not open, so try to use /dev/null */
174 int nullfd = open(_PATH_DEVNULL, mode);
175 /* /dev/null is major=1 minor=3. Make absolutely certain
176 * that is in fact the device that we have opened and not
177 * some other wierd file... [removed in uclibc] */
185 static int __check_suid(void)
198 return 0; /* we are not suid */
202 /* __uClibc_init completely initialize uClibc so it is ready to use.
204 * On ELF systems (with a dynamic loader) this function must be called
205 * from the dynamic loader (see TIS and ELF Specification), so that
206 * constructors of shared libraries (which depend on libc) can use all
207 * the libc code without restriction. For this we link the shared
208 * version of the uClibc with -init __uClibc_init so DT_INIT for
209 * uClibc is the address of __uClibc_init
211 * In all other cases we call it from the main stub
215 extern void __uClibc_init(void) attribute_hidden;
216 void __uClibc_init(void)
222 /* Setup an initial value. This may not be perfect, but is
223 * better than malloc using __pagesize=0 for atexit, ctors, etc. */
224 __pagesize = PAGE_SIZE;
226 #ifdef __UCLIBC_HAS_THREADS__
227 /* Before we start initializing uClibc we have to call
228 * __pthread_initialize_minimal so we can use pthread_locks
229 * whenever they are needed.
231 #if !defined (__UCLIBC_HAS_THREADS_NATIVE__) || defined (SHARED)
232 if (likely(__pthread_initialize_minimal!=NULL))
234 __pthread_initialize_minimal();
238 # ifdef __UCLIBC_HAS_SSP__
239 /* Set up the stack checker's canary. */
240 stack_chk_guard = _dl_setup_stack_chk_guard();
241 # ifdef THREAD_SET_STACK_GUARD
242 THREAD_SET_STACK_GUARD (stack_chk_guard);
244 __stack_chk_guard = stack_chk_guard;
246 # ifdef __UCLIBC_HAS_SSP_COMPAT__
247 __guard = stack_chk_guard;
252 #ifdef __UCLIBC_HAS_LOCALE__
253 /* Initialize the global locale structure. */
254 if (likely(not_null_ptr(_locale_init)))
259 * Initialize stdio here. In the static library case, this will
260 * be bypassed if not needed because of the weak alias above.
261 * Thus we get a nice size savings because the stdio functions
262 * won't be pulled into the final static binary unless used.
264 if (likely(not_null_ptr(_stdio_init)))
269 #ifdef __UCLIBC_CTOR_DTOR__
270 void attribute_hidden (*__app_fini)(void) = NULL;
273 void attribute_hidden (*__rtld_fini)(void) = NULL;
275 extern void __uClibc_fini(void) attribute_hidden;
276 void __uClibc_fini(void)
278 #ifdef __UCLIBC_CTOR_DTOR__
279 /* If __UCLIBC_FORMAT_SHARED_FLAT__, all array finalisation is handled
282 _dl_app_fini_array();
283 # elif !defined (__UCLIBC_FORMAT_SHARED_FLAT__)
284 size_t i = __fini_array_end - __fini_array_start;
286 (*__fini_array_start [i]) ();
288 if (__app_fini != NULL)
291 if (__rtld_fini != NULL)
296 extern void __nptl_deallocate_tsd (void) __attribute ((weak));
297 extern unsigned int __nptl_nthreads __attribute ((weak));
300 /* __uClibc_main is the new main stub for uClibc. This function is
301 * called from crt1 (version 0.9.28 or newer), after ALL shared libraries
302 * are initialized, just before we call the application's main function.
304 void __uClibc_main(int (*main)(int, char **, char **), int argc,
305 char **argv, void (*app_init)(void), void (*app_fini)(void),
306 void (*rtld_fini)(void),
307 void *stack_end attribute_unused) attribute_noreturn;
308 void __uClibc_main(int (*main)(int, char **, char **), int argc,
309 char **argv, void (*app_init)(void), void (*app_fini)(void),
310 void (*rtld_fini)(void), void *stack_end attribute_unused)
312 #ifndef __ARCH_HAS_NO_LDSO__
313 unsigned long *aux_dat;
314 ElfW(auxv_t) auxvt[AT_EGID + 1];
317 #ifdef __UCLIBC_HAS_THREADS_NATIVE__
318 /* Result of the 'main' function. */
323 __libc_stack_end = stack_end;
326 __rtld_fini = rtld_fini;
328 /* The environment begins right after argv. */
329 __environ = &argv[argc + 1];
331 /* If the first thing after argv is the arguments
332 * then the environment is empty. */
333 if ((char *) __environ == *argv) {
334 /* Make __environ point to the NULL at argv[argc] */
335 __environ = &argv[argc];
338 #ifndef __ARCH_HAS_NO_LDSO__
339 /* Pull stuff from the ELF header when possible */
340 memset(auxvt, 0x00, sizeof(auxvt));
341 aux_dat = (unsigned long*)__environ;
347 ElfW(auxv_t) *auxv_entry = (ElfW(auxv_t) *) aux_dat;
348 if (auxv_entry->a_type <= AT_EGID) {
349 memcpy(&(auxvt[auxv_entry->a_type]), auxv_entry, sizeof(ElfW(auxv_t)));
354 /* Get the program headers (_dl_phdr) from the aux vector
355 It will be used into __libc_setup_tls. */
357 _dl_aux_init (auxvt);
361 /* We need to initialize uClibc. If we are dynamically linked this
362 * may have already been completed by the shared lib loader. We call
363 * __uClibc_init() regardless, to be sure the right thing happens. */
366 #ifndef __ARCH_HAS_NO_LDSO__
367 /* Make certain getpagesize() gives the correct answer */
368 __pagesize = (auxvt[AT_PAGESZ].a_un.a_val)? auxvt[AT_PAGESZ].a_un.a_val : PAGE_SIZE;
370 /* Prevent starting SUID binaries where the stdin. stdout, and
371 * stderr file descriptors are not already opened. */
372 if ((auxvt[AT_UID].a_un.a_val == (size_t)-1 && __check_suid()) ||
373 (auxvt[AT_UID].a_un.a_val != (size_t)-1 &&
374 (auxvt[AT_UID].a_un.a_val != auxvt[AT_EUID].a_un.a_val ||
375 auxvt[AT_GID].a_un.a_val != auxvt[AT_EGID].a_un.a_val)))
377 __check_one_fd (STDIN_FILENO, O_RDONLY | O_NOFOLLOW);
378 __check_one_fd (STDOUT_FILENO, O_RDWR | O_NOFOLLOW);
379 __check_one_fd (STDERR_FILENO, O_RDWR | O_NOFOLLOW);
383 __uclibc_progname = *argv;
384 #ifdef __UCLIBC_HAS_PROGRAM_INVOCATION_NAME__
386 program_invocation_name = *argv;
387 program_invocation_short_name = strrchr(*argv, '/');
388 if (program_invocation_short_name != NULL)
389 ++program_invocation_short_name;
391 program_invocation_short_name = program_invocation_name;
395 #ifdef __UCLIBC_CTOR_DTOR__
396 /* Arrange for the application's dtors to run before we exit. */
397 __app_fini = app_fini;
399 /* If __UCLIBC_FORMAT_SHARED_FLAT__, all array initialisation is handled
401 # if !defined (SHARED) && !defined (__UCLIBC_FORMAT_SHARED_FLAT__)
402 /* For dynamically linked executables the preinit array is executed by
403 the dynamic linker (before initializing any shared object).
404 For static executables, preinit happens rights before init. */
406 const size_t size = __preinit_array_end - __preinit_array_start;
408 for (i = 0; i < size; i++)
409 (*__preinit_array_start [i]) ();
412 /* Run all the application's ctors now. */
413 if (app_init!=NULL) {
416 /* If __UCLIBC_FORMAT_SHARED_FLAT__, all array initialisation is handled
419 _dl_app_init_array();
420 # elif !defined (__UCLIBC_FORMAT_SHARED_FLAT__)
422 const size_t size = __init_array_end - __init_array_start;
424 for (i = 0; i < size; i++)
425 (*__init_array_start [i]) ();
430 /* Note: It is possible that any initialization done above could
431 * have resulted in errno being set nonzero, so set it to 0 before
434 if (likely(not_null_ptr(__errno_location)))
435 *(__errno_location()) = 0;
437 /* Set h_errno to 0 as well */
438 if (likely(not_null_ptr(__h_errno_location)))
439 *(__h_errno_location()) = 0;
441 #if defined HAVE_CLEANUP_JMP_BUF && defined __UCLIBC_HAS_THREADS_NATIVE__
442 /* Memory for the cancellation buffer. */
443 struct pthread_unwind_buf unwind_buf;
447 setjmp ((struct __jmp_buf_tag *) unwind_buf.cancel_jmp_buf);
448 if (__builtin_expect (! not_first_call, 1))
450 struct pthread *self = THREAD_SELF;
452 /* Store old info. */
453 unwind_buf.priv.data.prev = THREAD_GETMEM (self, cleanup_jmp_buf);
454 unwind_buf.priv.data.cleanup = THREAD_GETMEM (self, cleanup);
456 /* Store the new cleanup handler info. */
457 THREAD_SETMEM (self, cleanup_jmp_buf, &unwind_buf);
459 /* Run the program. */
460 result = main (argc, argv, __environ);
464 /* Remove the thread-local data. */
466 __libc_pthread_functions.ptr__nptl_deallocate_tsd ();
468 __nptl_deallocate_tsd ();
471 /* One less thread. Decrement the counter. If it is zero we
472 terminate the entire process. */
475 unsigned int *const ptr = __libc_pthread_functions.ptr_nthreads;
477 unsigned int *const ptr = &__nptl_nthreads;
480 if (! atomic_decrement_and_test (ptr))
481 /* Not much left to do but to exit the thread, not the process. */
482 __exit_thread_inline (0);
488 * Finally, invoke application's main and then exit.
490 exit (main (argc, argv, __environ));