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>
29 #include <asm/errno.h>
32 #include <sys/sysmacros.h>
33 #ifdef __UCLIBC_HAS_THREADS_NATIVE__
35 #include <pthread-functions.h>
36 #include <not-cancel.h>
39 #ifdef __UCLIBC_HAS_THREADS__
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 extern int *weak_const_function __errno_location(void);
120 extern int *weak_const_function __h_errno_location(void);
121 extern void weak_function _stdio_init(void) attribute_hidden;
122 #ifdef __UCLIBC_HAS_LOCALE__
123 extern void weak_function _locale_init(void) attribute_hidden;
125 #ifdef __UCLIBC_HAS_THREADS__
126 #if !defined (__UCLIBC_HAS_THREADS_NATIVE__) || defined (SHARED)
127 extern void weak_function __pthread_initialize_minimal(void);
129 extern void __pthread_initialize_minimal(void);
133 /* If __UCLIBC_FORMAT_SHARED_FLAT__, all array initialisation and finalisation
134 * is handled by the routines passed to __uClibc_main(). */
135 #if defined (__UCLIBC_CTOR_DTOR__) && !defined (__UCLIBC_FORMAT_SHARED_FLAT__)
136 extern void _dl_app_init_array(void);
137 extern void _dl_app_fini_array(void);
139 /* These magic symbols are provided by the linker. */
140 extern void (*__preinit_array_start []) (void) attribute_hidden;
141 extern void (*__preinit_array_end []) (void) attribute_hidden;
142 extern void (*__init_array_start []) (void) attribute_hidden;
143 extern void (*__init_array_end []) (void) attribute_hidden;
144 extern void (*__fini_array_start []) (void) attribute_hidden;
145 extern void (*__fini_array_end []) (void) attribute_hidden;
149 attribute_hidden const char *__uclibc_progname = "";
150 #ifdef __UCLIBC_HAS_PROGRAM_INVOCATION_NAME__
151 const char *program_invocation_short_name = "";
152 const char *program_invocation_name = "";
154 #ifdef __UCLIBC_HAS___PROGNAME__
155 weak_alias (program_invocation_short_name, __progname)
156 weak_alias (program_invocation_name, __progname_full)
160 * Declare the __environ global variable and create a weak alias environ.
161 * This must be initialized; we cannot have a weak alias into bss.
163 char **__environ = 0;
164 weak_alias(__environ, environ)
166 /* TODO: don't export __pagesize; we cant now because libpthread uses it */
167 size_t __pagesize = 0;
170 # define O_NOFOLLOW 0
173 #ifndef __ARCH_HAS_NO_LDSO__
174 static void __check_one_fd(int fd, int mode)
176 /* Check if the specified fd is already open */
177 if (fcntl(fd, F_GETFD) == -1)
179 /* The descriptor is probably not open, so try to use /dev/null */
180 int nullfd = open(_PATH_DEVNULL, mode);
181 /* /dev/null is major=1 minor=3. Make absolutely certain
182 * that is in fact the device that we have opened and not
183 * some other wierd file... [removed in uclibc] */
191 static int __check_suid(void)
204 return 0; /* we are not suid */
208 /* __uClibc_init completely initialize uClibc so it is ready to use.
210 * On ELF systems (with a dynamic loader) this function must be called
211 * from the dynamic loader (see TIS and ELF Specification), so that
212 * constructors of shared libraries (which depend on libc) can use all
213 * the libc code without restriction. For this we link the shared
214 * version of the uClibc with -init __uClibc_init so DT_INIT for
215 * uClibc is the address of __uClibc_init
217 * In all other cases we call it from the main stub
221 extern void __uClibc_init(void) attribute_hidden;
222 void __uClibc_init(void)
228 /* Setup an initial value. This may not be perfect, but is
229 * better than malloc using __pagesize=0 for atexit, ctors, etc. */
230 __pagesize = PAGE_SIZE;
232 #ifdef __UCLIBC_HAS_THREADS__
233 /* Before we start initializing uClibc we have to call
234 * __pthread_initialize_minimal so we can use pthread_locks
235 * whenever they are needed.
237 #if !defined (__UCLIBC_HAS_THREADS_NATIVE__) || defined (SHARED)
238 if (likely(__pthread_initialize_minimal!=NULL))
240 __pthread_initialize_minimal();
244 # ifdef __UCLIBC_HAS_SSP__
245 /* Set up the stack checker's canary. */
246 stack_chk_guard = _dl_setup_stack_chk_guard();
247 # ifdef THREAD_SET_STACK_GUARD
248 THREAD_SET_STACK_GUARD (stack_chk_guard);
250 __stack_chk_guard = stack_chk_guard;
252 # ifdef __UCLIBC_HAS_SSP_COMPAT__
253 __guard = stack_chk_guard;
258 #ifdef __UCLIBC_HAS_LOCALE__
259 /* Initialize the global locale structure. */
260 if (likely(not_null_ptr(_locale_init)))
265 * Initialize stdio here. In the static library case, this will
266 * be bypassed if not needed because of the weak alias above.
267 * Thus we get a nice size savings because the stdio functions
268 * won't be pulled into the final static binary unless used.
270 if (likely(not_null_ptr(_stdio_init)))
275 #ifdef __UCLIBC_CTOR_DTOR__
276 void attribute_hidden (*__app_fini)(void) = NULL;
279 void attribute_hidden (*__rtld_fini)(void) = NULL;
281 extern void __uClibc_fini(void) attribute_hidden;
282 void __uClibc_fini(void)
284 #ifdef __UCLIBC_CTOR_DTOR__
285 /* If __UCLIBC_FORMAT_SHARED_FLAT__, all array finalisation is handled
288 _dl_app_fini_array();
289 # elif !defined (__UCLIBC_FORMAT_SHARED_FLAT__)
290 size_t i = __fini_array_end - __fini_array_start;
292 (*__fini_array_start [i]) ();
294 if (__app_fini != NULL)
297 if (__rtld_fini != NULL)
302 extern void __nptl_deallocate_tsd (void) __attribute ((weak));
303 extern unsigned int __nptl_nthreads __attribute ((weak));
306 /* __uClibc_main is the new main stub for uClibc. This function is
307 * called from crt1 (version 0.9.28 or newer), after ALL shared libraries
308 * are initialized, just before we call the application's main function.
310 void __uClibc_main(int (*main)(int, char **, char **), int argc,
311 char **argv, void (*app_init)(void), void (*app_fini)(void),
312 void (*rtld_fini)(void),
313 void *stack_end attribute_unused) attribute_noreturn;
314 void __uClibc_main(int (*main)(int, char **, char **), int argc,
315 char **argv, void (*app_init)(void), void (*app_fini)(void),
316 void (*rtld_fini)(void), void *stack_end attribute_unused)
318 #ifndef __ARCH_HAS_NO_LDSO__
319 unsigned long *aux_dat;
320 ElfW(auxv_t) auxvt[AT_EGID + 1];
323 #ifdef __UCLIBC_HAS_THREADS_NATIVE__
324 /* Result of the 'main' function. */
329 __libc_stack_end = stack_end;
332 __rtld_fini = rtld_fini;
334 /* The environment begins right after argv. */
335 __environ = &argv[argc + 1];
337 /* If the first thing after argv is the arguments
338 * then the environment is empty. */
339 if ((char *) __environ == *argv) {
340 /* Make __environ point to the NULL at argv[argc] */
341 __environ = &argv[argc];
344 #ifndef __ARCH_HAS_NO_LDSO__
345 /* Pull stuff from the ELF header when possible */
346 memset(auxvt, 0x00, sizeof(auxvt));
347 aux_dat = (unsigned long*)__environ;
353 ElfW(auxv_t) *auxv_entry = (ElfW(auxv_t) *) aux_dat;
354 if (auxv_entry->a_type <= AT_EGID) {
355 memcpy(&(auxvt[auxv_entry->a_type]), auxv_entry, sizeof(ElfW(auxv_t)));
360 /* Get the program headers (_dl_phdr) from the aux vector
361 It will be used into __libc_setup_tls. */
363 _dl_aux_init (auxvt);
367 /* We need to initialize uClibc. If we are dynamically linked this
368 * may have already been completed by the shared lib loader. We call
369 * __uClibc_init() regardless, to be sure the right thing happens. */
372 #ifndef __ARCH_HAS_NO_LDSO__
373 /* Make certain getpagesize() gives the correct answer */
374 __pagesize = (auxvt[AT_PAGESZ].a_un.a_val)? auxvt[AT_PAGESZ].a_un.a_val : PAGE_SIZE;
376 /* Prevent starting SUID binaries where the stdin. stdout, and
377 * stderr file descriptors are not already opened. */
378 if ((auxvt[AT_UID].a_un.a_val == (size_t)-1 && __check_suid()) ||
379 (auxvt[AT_UID].a_un.a_val != (size_t)-1 &&
380 (auxvt[AT_UID].a_un.a_val != auxvt[AT_EUID].a_un.a_val ||
381 auxvt[AT_GID].a_un.a_val != auxvt[AT_EGID].a_un.a_val)))
383 __check_one_fd (STDIN_FILENO, O_RDONLY | O_NOFOLLOW);
384 __check_one_fd (STDOUT_FILENO, O_RDWR | O_NOFOLLOW);
385 __check_one_fd (STDERR_FILENO, O_RDWR | O_NOFOLLOW);
389 __uclibc_progname = *argv;
390 #ifdef __UCLIBC_HAS_PROGRAM_INVOCATION_NAME__
392 program_invocation_name = *argv;
393 program_invocation_short_name = strrchr(*argv, '/');
394 if (program_invocation_short_name != NULL)
395 ++program_invocation_short_name;
397 program_invocation_short_name = program_invocation_name;
401 #ifdef __UCLIBC_CTOR_DTOR__
402 /* Arrange for the application's dtors to run before we exit. */
403 __app_fini = app_fini;
405 /* If __UCLIBC_FORMAT_SHARED_FLAT__, all array initialisation is handled
407 # if !defined (SHARED) && !defined (__UCLIBC_FORMAT_SHARED_FLAT__)
408 /* For dynamically linked executables the preinit array is executed by
409 the dynamic linker (before initializing any shared object).
410 For static executables, preinit happens rights before init. */
412 const size_t size = __preinit_array_end - __preinit_array_start;
414 for (i = 0; i < size; i++)
415 (*__preinit_array_start [i]) ();
418 /* Run all the application's ctors now. */
419 if (app_init!=NULL) {
422 /* If __UCLIBC_FORMAT_SHARED_FLAT__, all array initialisation is handled
425 _dl_app_init_array();
426 # elif !defined (__UCLIBC_FORMAT_SHARED_FLAT__)
428 const size_t size = __init_array_end - __init_array_start;
430 for (i = 0; i < size; i++)
431 (*__init_array_start [i]) ();
436 /* Note: It is possible that any initialization done above could
437 * have resulted in errno being set nonzero, so set it to 0 before
440 if (likely(not_null_ptr(__errno_location)))
441 *(__errno_location()) = 0;
443 /* Set h_errno to 0 as well */
444 if (likely(not_null_ptr(__h_errno_location)))
445 *(__h_errno_location()) = 0;
447 #if defined HAVE_CLEANUP_JMP_BUF && defined __UCLIBC_HAS_THREADS_NATIVE__
448 /* Memory for the cancellation buffer. */
449 struct pthread_unwind_buf unwind_buf;
453 setjmp ((struct __jmp_buf_tag *) unwind_buf.cancel_jmp_buf);
454 if (__builtin_expect (! not_first_call, 1))
456 struct pthread *self = THREAD_SELF;
458 /* Store old info. */
459 unwind_buf.priv.data.prev = THREAD_GETMEM (self, cleanup_jmp_buf);
460 unwind_buf.priv.data.cleanup = THREAD_GETMEM (self, cleanup);
462 /* Store the new cleanup handler info. */
463 THREAD_SETMEM (self, cleanup_jmp_buf, &unwind_buf);
465 /* Run the program. */
466 result = main (argc, argv, __environ);
470 /* Remove the thread-local data. */
472 __libc_pthread_functions.ptr__nptl_deallocate_tsd ();
474 __nptl_deallocate_tsd ();
477 /* One less thread. Decrement the counter. If it is zero we
478 terminate the entire process. */
481 unsigned int *const ptr = __libc_pthread_functions.ptr_nthreads;
483 unsigned int *const ptr = &__nptl_nthreads;
486 if (! atomic_decrement_and_test (ptr))
487 /* Not much left to do but to exit the thread, not the process. */
488 __exit_thread_inline (0);
494 * Finally, invoke application's main and then exit.
496 exit (main (argc, argv, __environ));