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.
18 #ifndef __UCLIBC_HAS_THREADS_NATIVE__
26 #include <bits/uClibc_page.h>
30 #include <asm/errno.h>
34 #include <sys/sysmacros.h>
35 #ifdef __UCLIBC_HAS_THREADS_NATIVE__
37 #include <pthread-functions.h>
38 #include <not-cancel.h>
41 #ifdef __UCLIBC_HAS_THREADS__
46 void *__libc_stack_end = NULL;
48 # ifdef __UCLIBC_HAS_SSP__
49 # include <dl-osinfo.h>
50 # ifndef THREAD_SET_STACK_GUARD
51 /* Only exported for architectures that don't store the stack guard canary
52 * in thread local area. */
54 uintptr_t stack_chk_guard;
55 /* for gcc-4.1 non-TLS */
56 uintptr_t __stack_chk_guard attribute_relro;
57 /* for gcc-3.x + Etoh ssp */
58 # ifdef __UCLIBC_HAS_SSP_COMPAT__
59 # ifdef __HAVE_SHARED__
60 strong_alias(__stack_chk_guard,__guard)
62 uintptr_t __guard attribute_relro;
65 # elif defined __UCLIBC_HAS_SSP_COMPAT__
66 uintptr_t __guard attribute_relro;
71 * Needed to initialize _dl_phdr when statically linked
74 void internal_function _dl_aux_init (ElfW(auxv_t) *av);
76 #ifdef __UCLIBC_HAS_THREADS__
78 * uClibc internal locking requires that we have weak aliases
79 * for dummy functions in case libpthread.a is not linked in.
80 * This needs to be in compilation unit that is pulled always
81 * in or linker will disregard these weaks.
84 static int __pthread_return_0 (pthread_mutex_t *unused) { return 0; }
85 weak_alias (__pthread_return_0, __pthread_mutex_lock)
86 weak_alias (__pthread_return_0, __pthread_mutex_trylock)
87 weak_alias (__pthread_return_0, __pthread_mutex_unlock)
90 __pthread_mutex_init(pthread_mutex_t *mutex, const pthread_mutexattr_t *attr)
96 _pthread_cleanup_push_defer(struct _pthread_cleanup_buffer *__buffer,
97 void (*__routine) (void *), void *__arg)
99 __buffer->__routine = __routine;
100 __buffer->__arg = __arg;
104 _pthread_cleanup_pop_restore(struct _pthread_cleanup_buffer *__buffer,
108 __buffer->__routine(__buffer->__arg);
110 #endif /* __UCLIBC_HAS_THREADS__ */
114 /* Defeat compiler optimization which assumes function addresses are never NULL */
115 static __always_inline int not_null_ptr(const void *p)
119 : "=r" (q) /* output */
120 : "0" (p) /* input */
128 extern int *weak_const_function __errno_location(void);
129 extern int *weak_const_function __h_errno_location(void);
130 /* aw11: hidden and weak in a statically linked library meaningless
131 * and gold in x86_64 complains about
134 extern void weak_function _stdio_init(void) attribute_hidden;
136 extern void weak_function _stdio_init(void);
138 #ifdef __UCLIBC_HAS_LOCALE__
139 extern void weak_function _locale_init(void) attribute_hidden;
141 #ifdef __UCLIBC_HAS_THREADS__
142 #if !defined (__UCLIBC_HAS_THREADS_NATIVE__) || defined (SHARED)
143 extern void weak_function __pthread_initialize_minimal(void);
145 extern void __pthread_initialize_minimal(void);
149 /* If __UCLIBC_FORMAT_SHARED_FLAT__, all array initialisation and finalisation
150 * is handled by the routines passed to __uClibc_main(). */
151 #if defined (__UCLIBC_CTOR_DTOR__) && !defined (__UCLIBC_FORMAT_SHARED_FLAT__)
152 extern void _dl_app_init_array(void);
153 extern void _dl_app_fini_array(void);
155 /* These magic symbols are provided by the linker. */
156 extern void (*__preinit_array_start []) (void) attribute_hidden;
157 extern void (*__preinit_array_end []) (void) attribute_hidden;
158 extern void (*__init_array_start []) (void) attribute_hidden;
159 extern void (*__init_array_end []) (void) attribute_hidden;
160 extern void (*__fini_array_start []) (void) attribute_hidden;
161 extern void (*__fini_array_end []) (void) attribute_hidden;
165 attribute_hidden const char *__uclibc_progname = "";
166 #ifdef __UCLIBC_HAS_PROGRAM_INVOCATION_NAME__
167 const char *program_invocation_short_name = "";
168 const char *program_invocation_name = "";
170 #ifdef __UCLIBC_HAS___PROGNAME__
171 weak_alias (program_invocation_short_name, __progname)
172 weak_alias (program_invocation_name, __progname_full)
176 * Declare the __environ global variable and create a weak alias environ.
177 * This must be initialized; we cannot have a weak alias into bss.
179 char **__environ = 0;
180 weak_alias(__environ, environ)
182 /* TODO: don't export __pagesize; we cant now because libpthread uses it */
183 size_t __pagesize = 0;
186 # define O_NOFOLLOW 0
189 #ifndef __ARCH_HAS_NO_LDSO__
190 static void __check_one_fd(int fd, int mode)
192 #ifdef __NOT_FOR_L4__
193 /* Check if the specified fd is already open */
194 if (fcntl(fd, F_GETFD) == -1)
196 /* The descriptor is probably not open, so try to use /dev/null */
197 int nullfd = open(_PATH_DEVNULL, mode);
198 /* /dev/null is major=1 minor=3. Make absolutely certain
199 * that is in fact the device that we have opened and not
200 * some other wierd file... [removed in uclibc] */
209 static int __check_suid(void)
211 #ifdef __NOT_FOR_L4__
224 return 0; /* we are not suid */
228 /* __uClibc_init completely initialize uClibc so it is ready to use.
230 * On ELF systems (with a dynamic loader) this function must be called
231 * from the dynamic loader (see TIS and ELF Specification), so that
232 * constructors of shared libraries (which depend on libc) can use all
233 * the libc code without restriction. For this we link the shared
234 * version of the uClibc with -init __uClibc_init so DT_INIT for
235 * uClibc is the address of __uClibc_init
237 * In all other cases we call it from the main stub
241 extern void __uClibc_init(void);
242 libc_hidden_proto(__uClibc_init)
243 void __uClibc_init(void)
249 /* Setup an initial value. This may not be perfect, but is
250 * better than malloc using __pagesize=0 for atexit, ctors, etc. */
251 __pagesize = PAGE_SIZE;
253 #ifdef __UCLIBC_HAS_THREADS__
254 /* Before we start initializing uClibc we have to call
255 * __pthread_initialize_minimal so we can use pthread_locks
256 * whenever they are needed.
258 #if !defined (__UCLIBC_HAS_THREADS_NATIVE__) || defined (SHARED)
259 if (likely(__pthread_initialize_minimal!=NULL))
261 __pthread_initialize_minimal();
265 # ifdef __UCLIBC_HAS_SSP__
266 /* Set up the stack checker's canary. */
267 # ifdef THREAD_SET_STACK_GUARD
268 uintptr_t stack_chk_guard = _dl_setup_stack_chk_guard();
269 THREAD_SET_STACK_GUARD (stack_chk_guard);
270 # ifdef __UCLIBC_HAS_SSP_COMPAT__
271 stack_chk_guard = _dl_setup_stack_chk_guard();
272 __guard = stack_chk_guard;
275 __stack_chk_guard = stack_chk_guard;
276 # if !defined __HAVE_SHARED__ && defined __UCLIBC_HAS_SSP_COMPAT__
277 __guard = stack_chk_guard;
283 #ifdef __UCLIBC_HAS_LOCALE__
284 /* Initialize the global locale structure. */
285 if (likely(not_null_ptr(_locale_init)))
290 * Initialize stdio here. In the static library case, this will
291 * be bypassed if not needed because of the weak alias above.
292 * Thus we get a nice size savings because the stdio functions
293 * won't be pulled into the final static binary unless used.
295 if (likely(not_null_ptr(_stdio_init)))
299 libc_hidden_def(__uClibc_init)
301 #ifdef __UCLIBC_CTOR_DTOR__
302 void attribute_hidden (*__app_fini)(void) = NULL;
305 void attribute_hidden (*__rtld_fini)(void) = NULL;
307 extern void __uClibc_fini(void);
308 libc_hidden_proto(__uClibc_fini)
309 void __uClibc_fini(void)
311 #ifdef __UCLIBC_CTOR_DTOR__
312 /* If __UCLIBC_FORMAT_SHARED_FLAT__, all array finalisation is handled
315 _dl_app_fini_array();
316 # elif !defined (__UCLIBC_FORMAT_SHARED_FLAT__)
317 size_t i = __fini_array_end - __fini_array_start;
319 (*__fini_array_start [i]) ();
321 if (__app_fini != NULL)
324 if (__rtld_fini != NULL)
327 libc_hidden_def(__uClibc_fini)
329 #ifndef __NOT_FOR_L4__
330 extern void *l4re_global_env __attribute__((weak));
333 /* __uClibc_main is the new main stub for uClibc. This function is
334 * called from crt1 (version 0.9.28 or newer), after ALL shared libraries
335 * are initialized, just before we call the application's main function.
337 void __uClibc_main(int (*main)(int, char **, char **), int argc,
338 char **argv, void (*app_init)(void), void (*app_fini)(void),
339 void (*rtld_fini)(void),
340 void *stack_end attribute_unused) attribute_noreturn;
341 void __uClibc_main(int (*main)(int, char **, char **), int argc,
342 char **argv, void (*app_init)(void), void (*app_fini)(void),
343 void (*rtld_fini)(void), void *stack_end attribute_unused)
345 #ifndef __ARCH_HAS_NO_LDSO__
346 unsigned long *aux_dat;
347 ElfW(auxv_t) auxvt[AT_EGID + 1];
350 #ifdef __UCLIBC_HAS_THREADS_NATIVE__
351 /* Result of the 'main' function. */
356 __libc_stack_end = stack_end;
359 __rtld_fini = rtld_fini;
361 /* The environment begins right after argv. */
362 __environ = &argv[argc + 1];
364 /* If the first thing after argv is the arguments
365 * the the environment is empty. */
366 if ((char *) __environ == *argv) {
367 /* Make __environ point to the NULL at argv[argc] */
368 __environ = &argv[argc];
371 #ifndef __ARCH_HAS_NO_LDSO__
372 /* Pull stuff from the ELF header when possible */
373 memset(auxvt, 0x00, sizeof(auxvt));
374 aux_dat = (unsigned long*)__environ;
380 ElfW(auxv_t) *auxv_entry = (ElfW(auxv_t) *) aux_dat;
381 if (auxv_entry->a_type <= AT_EGID) {
382 memcpy(&(auxvt[auxv_entry->a_type]), auxv_entry, sizeof(ElfW(auxv_t)));
384 #ifndef __NOT_FOR_L4__
385 if (auxv_entry->a_type == 0xf1 && &l4re_global_env)
387 l4re_global_env = (void*)auxv_entry->a_un.a_val;
393 /* Get the program headers (_dl_phdr) from the aux vector
394 It will be used into __libc_setup_tls. */
396 _dl_aux_init (auxvt);
400 /* We need to initialize uClibc. If we are dynamically linked this
401 * may have already been completed by the shared lib loader. We call
402 * __uClibc_init() regardless, to be sure the right thing happens. */
405 #ifndef __ARCH_HAS_NO_LDSO__
406 /* Make certain getpagesize() gives the correct answer */
407 __pagesize = (auxvt[AT_PAGESZ].a_un.a_val)? auxvt[AT_PAGESZ].a_un.a_val : PAGE_SIZE;
409 /* Prevent starting SUID binaries where the stdin. stdout, and
410 * stderr file descriptors are not already opened. */
411 if ((auxvt[AT_UID].a_un.a_val == (size_t)-1 && __check_suid()) ||
412 (auxvt[AT_UID].a_un.a_val != (size_t)-1 &&
413 (auxvt[AT_UID].a_un.a_val != auxvt[AT_EUID].a_un.a_val ||
414 auxvt[AT_GID].a_un.a_val != auxvt[AT_EGID].a_un.a_val)))
416 __check_one_fd (STDIN_FILENO, O_RDONLY | O_NOFOLLOW);
417 __check_one_fd (STDOUT_FILENO, O_RDWR | O_NOFOLLOW);
418 __check_one_fd (STDERR_FILENO, O_RDWR | O_NOFOLLOW);
422 __uclibc_progname = *argv;
423 #ifdef __UCLIBC_HAS_PROGRAM_INVOCATION_NAME__
425 program_invocation_name = *argv;
426 program_invocation_short_name = strrchr(*argv, '/');
427 if (program_invocation_short_name != NULL)
428 ++program_invocation_short_name;
430 program_invocation_short_name = program_invocation_name;
434 #ifdef __UCLIBC_CTOR_DTOR__
435 /* Arrange for the application's dtors to run before we exit. */
436 __app_fini = app_fini;
438 /* If __UCLIBC_FORMAT_SHARED_FLAT__, all array initialisation is handled
440 # if !defined (SHARED) && !defined (__UCLIBC_FORMAT_SHARED_FLAT__)
441 /* For dynamically linked executables the preinit array is executed by
442 the dynamic linker (before initializing any shared object).
443 For static executables, preinit happens rights before init. */
445 const size_t size = __preinit_array_end - __preinit_array_start;
447 for (i = 0; i < size; i++)
448 (*__preinit_array_start [i]) ();
451 /* Run all the application's ctors now. */
452 if (app_init!=NULL) {
455 /* If __UCLIBC_FORMAT_SHARED_FLAT__, all array initialisation is handled
458 _dl_app_init_array();
459 # elif !defined (__UCLIBC_FORMAT_SHARED_FLAT__)
461 const size_t size = __init_array_end - __init_array_start;
463 for (i = 0; i < size; i++)
464 (*__init_array_start [i]) ();
469 /* Note: It is possible that any initialization done above could
470 * have resulted in errno being set nonzero, so set it to 0 before
473 if (likely(not_null_ptr(__errno_location)))
474 *(__errno_location()) = 0;
476 /* Set h_errno to 0 as well */
477 if (likely(not_null_ptr(__h_errno_location)))
478 *(__h_errno_location()) = 0;
480 #if defined HAVE_CLEANUP_JMP_BUF && defined __UCLIBC_HAS_THREADS_NATIVE__
481 /* Memory for the cancellation buffer. */
482 struct pthread_unwind_buf unwind_buf;
486 setjmp ((struct __jmp_buf_tag *) unwind_buf.cancel_jmp_buf);
487 if (__builtin_expect (! not_first_call, 1))
489 struct pthread *self = THREAD_SELF;
491 /* Store old info. */
492 unwind_buf.priv.data.prev = THREAD_GETMEM (self, cleanup_jmp_buf);
493 unwind_buf.priv.data.cleanup = THREAD_GETMEM (self, cleanup);
495 /* Store the new cleanup handler info. */
496 THREAD_SETMEM (self, cleanup_jmp_buf, &unwind_buf);
498 /* Run the program. */
499 result = main (argc, argv, __environ);
503 /* Remove the thread-local data. */
505 __libc_pthread_functions.ptr__nptl_deallocate_tsd ();
507 extern void __nptl_deallocate_tsd (void) __attribute ((weak));
508 __nptl_deallocate_tsd ();
511 /* One less thread. Decrement the counter. If it is zero we
512 terminate the entire process. */
515 unsigned int *const ptr = __libc_pthread_functions.ptr_nthreads;
517 extern unsigned int __nptl_nthreads __attribute ((weak));
518 unsigned int *const ptr = &__nptl_nthreads;
521 if (! atomic_decrement_and_test (ptr))
522 /* Not much left to do but to exit the thread, not the process. */
523 __exit_thread_inline (0);
529 * Finally, invoke application's main and then exit.
531 exit (main (argc, argv, __environ));