1 /* Initialization code run first thing by the ELF startup code. For i386/Hurd.
2 Copyright (C) 1995-2018 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
26 #include <set-hooks.h>
27 #include "hurdstartup.h"
28 #include "hurdmalloc.h" /* XXX */
29 #include "../locale/localeinfo.h"
32 #include <fpu_control.h>
34 extern void __mach_init (void);
35 extern void __init_misc (int, char **, char **);
36 extern void __libc_global_ctors (void);
38 unsigned long int __hurd_threadvar_stack_offset
;
39 unsigned long int __hurd_threadvar_stack_mask
;
42 int __libc_enable_secure
;
44 int __libc_multiple_libcs attribute_hidden
= 1;
46 extern int __libc_argc attribute_hidden
;
47 extern char **__libc_argv attribute_hidden
;
48 extern char **_dl_argv
;
50 extern void *(*_cthread_init_routine
) (void) __attribute__ ((weak
));
51 void (*_cthread_exit_routine
) (int status
) __attribute__ ((__noreturn__
));
53 /* Things that want to be run before _hurd_init or much anything else.
54 Importantly, these are called before anything tries to use malloc. */
55 DEFINE_HOOK (_hurd_preinit_hook
, (void));
58 /* We call this once the Hurd magic is all set up and we are ready to be a
59 Posixoid program. This does the same things the generic version does. */
61 posixland_init (int argc
, char **argv
, char **envp
)
63 __libc_multiple_libcs
= &_dl_starting_up
&& !_dl_starting_up
;
65 /* Make sure we don't initialize twice. */
66 if (!__libc_multiple_libcs
)
68 /* Set the FPU control word to the proper default value. */
69 __setfpucw (__fpu_control
);
73 /* Initialize data structures so the additional libc can do RPCs. */
77 /* Save the command-line arguments. */
83 _dl_non_dynamic_init ();
85 __init_misc (argc
, argv
, envp
);
87 /* Initialize ctype data. */
90 #if defined SHARED && !defined NO_CTORS_DTORS_SECTIONS
91 __libc_global_ctors ();
97 init1 (int argc
, char *arg0
, ...)
100 char **envp
= &argv
[argc
+ 1];
101 struct hurd_startup_data
*d
;
107 /* If we are the bootstrap task started by the kernel,
108 then after the environment pointers there is no Hurd
109 data block; the argument strings start there. */
110 if ((void *) d
== argv
[0] || d
->phdr
== 0)
113 /* With a new enough linker (binutils-2.23 or better),
114 the magic __ehdr_start symbol will be available and
115 __libc_start_main will have done this that way already. */
116 if (_dl_phdr
== NULL
)
118 /* We may need to see our own phdrs, e.g. for TLS setup.
119 Try the usual kludge to find the headers without help from
121 extern const void __executable_start
;
122 const ElfW(Ehdr
) *const ehdr
= &__executable_start
;
123 _dl_phdr
= (const void *) ehdr
+ ehdr
->e_phoff
;
124 _dl_phnum
= ehdr
->e_phnum
;
125 assert (ehdr
->e_phentsize
== sizeof (ElfW(Phdr
)));
132 __libc_enable_secure
= d
->flags
& EXEC_SECURE
;
134 _dl_phdr
= (ElfW(Phdr
) *) d
->phdr
;
135 _dl_phnum
= d
->phdrsz
/ sizeof (ElfW(Phdr
));
136 assert (d
->phdrsz
% sizeof (ElfW(Phdr
)) == 0);
139 _hurd_init_dtable
= d
->dtable
;
140 _hurd_init_dtablesize
= d
->dtablesize
;
143 /* Check if the stack we are now on is different from
144 the one described by _hurd_stack_{base,size}. */
147 const vm_address_t newsp
= (vm_address_t
) &dummy
;
149 if (d
->stack_size
!= 0 && (newsp
< d
->stack_base
||
150 newsp
- d
->stack_base
> d
->stack_size
))
151 /* The new stack pointer does not intersect with the
152 stack the exec server set up for us, so free that stack. */
153 __vm_deallocate (__mach_task_self (), d
->stack_base
, d
->stack_size
);
156 if (d
->portarray
|| d
->intarray
)
157 /* Initialize library data structures, start signal processing, etc. */
158 _hurd_init (d
->flags
, argv
,
159 d
->portarray
, d
->portarraysize
,
160 d
->intarray
, d
->intarraysize
);
168 char **argv
= (void *) (data
+ 1);
169 char **envp
= &argv
[argc
+ 1];
170 struct hurd_startup_data
*d
;
172 /* Since the cthreads initialization code uses malloc, and the
173 malloc initialization code needs to get at the environment, make
174 sure we can find it. We'll need to do this again later on since
175 switching stacks changes the location where the environment is
184 /* After possibly switching stacks, call `init1' (above) with the user
185 code as the return address, and the argument data immediately above
186 that on the stack. */
188 if (&_cthread_init_routine
&& _cthread_init_routine
)
190 /* Initialize cthreads, which will allocate us a new stack to run on. */
191 int *newsp
= (*_cthread_init_routine
) ();
192 struct hurd_startup_data
*od
;
194 void switch_stacks (void);
196 __libc_stack_end
= newsp
;
198 /* Copy the argdata from the old stack to the new one. */
199 newsp
= memcpy (newsp
- ((char *) &d
[1] - (char *) data
), data
,
200 (char *) d
- (char *) data
);
203 /* And readjust the dynamic linker's idea of where the argument
205 assert (_dl_argv
== argv
);
206 _dl_argv
= (void *) (newsp
+ 1);
209 /* Set up the Hurd startup data block immediately following
210 the argument and environment pointers on the new stack. */
211 od
= ((void *) newsp
+ ((char *) d
- (char *) data
));
212 if ((void *) argv
[0] == d
)
213 /* We were started up by the kernel with arguments on the stack.
214 There is no Hurd startup data, so zero the block. */
215 memset (od
, 0, sizeof *od
);
217 /* Copy the Hurd startup data block to the new stack. */
220 /* Push the user code address on the top of the new stack. It will
221 be the return address for `init1'; we will jump there with NEWSP
222 as the stack pointer. */
223 /* The following expression would typically be written as
224 ``__builtin_return_address (0)''. But, for example, GCC 4.4.6 doesn't
225 recognize that this read operation may alias the following write
226 operation, and thus is free to reorder the two, clobbering the
227 original return address. */
228 *--newsp
= *((int *) __builtin_frame_address (0) + 1);
229 /* GCC 4.4.6 also wants us to force loading *NEWSP already here. */
230 asm volatile ("# %0" : : "X" (*newsp
));
231 *((void **) __builtin_frame_address (0) + 1) = &switch_stacks
;
232 /* Force NEWSP into %eax and &init1 into %ecx, which are not restored
233 by function return. */
234 asm volatile ("# a %0 c %1" : : "a" (newsp
), "c" (&init1
));
240 void call_init1 (void);
242 /* The argument data is just above the stack frame we will unwind by
243 returning. Mutate our own return address to run the code below. */
244 /* The following expression would typically be written as
245 ``__builtin_return_address (0)''. But, for example, GCC 4.4.6 doesn't
246 recognize that this read operation may alias the following write
247 operation, and thus is free to reorder the two, clobbering the
248 original return address. */
249 usercode
= *((int *) __builtin_frame_address (0) + 1);
250 /* GCC 4.4.6 also wants us to force loading USERCODE already here. */
251 asm volatile ("# %0" : : "X" (usercode
));
252 *((void **) __builtin_frame_address (0) + 1) = &call_init1
;
253 /* Force USERCODE into %eax and &init1 into %ecx, which are not
254 restored by function return. */
255 asm volatile ("# a %0 c %1" : : "a" (usercode
), "c" (&init1
));
259 /* These bits of inline assembler used to be located inside `init'.
260 However they were optimized away by gcc 2.95. */
262 /* The return address of `init' above, was redirected to here, so at
263 this point our stack is unwound and callers' registers restored.
264 Only %ecx and %eax are call-clobbered and thus still have the
265 values we set just above. Fetch from there the new stack pointer
266 we will run on, and jmp to the run-time address of `init1'; when it
267 returns, it will run the user code with the argument data at the
269 asm ("switch_stacks:\n"
273 /* As in the stack-switching case, at this point our stack is unwound
274 and callers' registers restored, and only %ecx and %eax communicate
275 values from the lines above. In this case we have stashed in %eax
276 the user code return address. Push it on the top of the stack so
277 it acts as init1's return address, and then jump there. */
283 /* Do the first essential initializations that must precede all else. */
287 /* Initialize data structures so we can do RPCs. */
290 RUN_HOOK (_hurd_preinit_hook
, ());
294 /* This function is called specially by the dynamic linker to do early
295 initialization of the shared C library before normal initializers
296 expecting a Posixoid environment can run. It gets called with the
297 stack set up just as the user will see it, so it can switch stacks. */
300 _dl_init_first (int argc
, ...)
304 /* If we use ``__builtin_frame_address (0) + 2'' here, GCC gets confused. */
311 /* The regular posixland initialization is what goes into libc's
312 normal initializer. */
313 /* NOTE! The linker notices the magical name `_init' and sets the DT_INIT
314 pointer in the dynamic section based solely on that. It is convention
315 for this function to be in the `.init' section, but the symbol name is
316 the only thing that really matters!! */
317 strong_alias (posixland_init
, _init
);
320 __libc_init_first (int argc
, char **argv
, char **envp
)
322 /* Everything was done in the shared library initializer, _init. */
325 strong_alias (posixland_init
, __libc_init_first
);
328 /* XXX This is all a crock and I am not happy with it.
329 This poorly-named function is called by static-start.S,
330 which should not exist at all. */
332 _hurd_stack_setup (void)
334 intptr_t caller
= (intptr_t) __builtin_return_address (0);
336 void doinit (intptr_t *data
)
338 /* This function gets called with the argument data at TOS. */
339 void doinit1 (int argc
, ...)
341 /* If we use ``__builtin_frame_address (0) + 2'' here, GCC gets
343 init ((int *) &argc
);
346 /* Push the user return address after the argument data, and then
347 jump to `doinit1' (above), so it is as if __libc_init_first's
348 caller had called `doinit1' with the argument data already on the
351 asm volatile ("movl %0, %%esp\n" /* Switch to new outermost stack. */
352 "movl $0, %%ebp\n" /* Clear outermost frame pointer. */
353 "jmp *%1" : : "r" (data
), "r" (&doinit1
) : "sp");
359 _hurd_startup ((void **) __builtin_frame_address (0) + 2, &doinit
);
364 /* This function is defined here so that if this file ever gets into
365 ld.so we will get a link error. Having this file silently included
366 in ld.so causes disaster, because the _init definition above will
367 cause ld.so to gain an init function, which is not a cool thing. */