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- /* __cxa_atexit backwards-compatibility support for Darwin.
- Copyright (C) 2006-2022 Free Software Foundation, Inc.
- This file is part of GCC.
- GCC is free software; you can redistribute it and/or modify it under
- the terms of the GNU General Public License as published by the Free
- Software Foundation; either version 3, or (at your option) any later
- version.
- GCC 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 General Public License
- for more details.
- Under Section 7 of GPL version 3, you are granted additional
- permissions described in the GCC Runtime Library Exception, version
- 3.1, as published by the Free Software Foundation.
- You should have received a copy of the GNU General Public License and
- a copy of the GCC Runtime Library Exception along with this program;
- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
- <http://www.gnu.org/licenses/>. */
- /* Don't do anything if we are compiling for a kext multilib. */
- #ifdef __PIC__
- #include "tconfig.h"
- #include "tsystem.h"
- #include <dlfcn.h>
- #include <stdbool.h>
- #include <stdlib.h>
- #include <string.h>
- /* This file works around two different problems.
- The first problem is that there is no __cxa_atexit on Mac OS versions
- before 10.4. It fixes this by providing a complete atexit and
- __cxa_atexit emulation called from the regular atexit.
- The second problem is that on all shipping versions of Mac OS,
- __cxa_finalize and exit() don't work right: they don't run routines
- that were registered while other atexit routines are running. This
- is worked around by wrapping each atexit/__cxa_atexit routine with
- our own routine which ensures that any __cxa_atexit calls while it
- is running are honoured.
- There are still problems which this does not solve. Before 10.4,
- shared objects linked with previous compilers won't have their
- atexit calls properly interleaved with code compiled with newer
- compilers. Also, atexit routines registered from shared objects
- linked with previous compilers won't get the bug fix. */
- typedef int (*cxa_atexit_p)(void (*func) (void*), void* arg, const void* dso);
- typedef void (*cxa_finalize_p)(const void *dso);
- typedef int (*atexit_p)(void (*func)(void));
- /* These are from "keymgr.h". */
- extern void *_keymgr_get_and_lock_processwide_ptr (unsigned key);
- extern int _keymgr_get_and_lock_processwide_ptr_2 (unsigned, void **);
- extern int _keymgr_set_and_unlock_processwide_ptr (unsigned key, void *ptr);
- extern void *__keymgr_global[];
- typedef struct _Sinfo_Node {
- unsigned int size ; /*size of this node*/
- unsigned short major_version ; /*API major version.*/
- unsigned short minor_version ; /*API minor version.*/
- } _Tinfo_Node ;
- #ifdef __ppc__
- #define CHECK_KEYMGR_ERROR(e) \
- (((_Tinfo_Node *)__keymgr_global[2])->major_version >= 4 ? (e) : 0)
- #else
- #define CHECK_KEYMGR_ERROR(e) (e)
- #endif
- /* Our globals are stored under this keymgr index. */
- #define KEYMGR_ATEXIT_LIST 14
- /* The different kinds of callback routines. */
- typedef void (*atexit_callback)(void);
- typedef void (*cxa_atexit_callback)(void *);
- /* This structure holds a routine to call. There may be extra fields
- at the end of the structure that this code doesn't know about. */
- struct one_atexit_routine
- {
- union {
- atexit_callback ac;
- cxa_atexit_callback cac;
- } callback;
- /* has_arg is 0/2/4 if 'ac' is live, 1/3/5 if 'cac' is live.
- Higher numbers indicate a later version of the structure that this
- code doesn't understand and will ignore. */
- int has_arg;
- void * arg;
- };
- struct atexit_routine_list
- {
- struct atexit_routine_list * next;
- struct one_atexit_routine r;
- };
- /* The various possibilities for status of atexit(). */
- enum atexit_status {
- atexit_status_unknown = 0,
- atexit_status_missing = 1,
- atexit_status_broken = 2,
- atexit_status_working = 16
- };
- struct keymgr_atexit_list
- {
- /* Version of this list. This code knows only about version 0.
- If the version is higher than 0, this code may add new atexit routines
- but should not attempt to run the list. */
- short version;
- /* 1 if an atexit routine is currently being run by this code, 0
- otherwise. */
- char running_routines;
- /* Holds a value from 'enum atexit_status'. */
- unsigned char atexit_status;
- /* The list of atexit and cxa_atexit routines registered. If
- atexit_status_missing it contains all routines registered while
- linked with this code. If atexit_status_broken it contains all
- routines registered during cxa_finalize while linked with this
- code. */
- struct atexit_routine_list *l;
- /* &__cxa_atexit; set if atexit_status >= atexit_status_broken. */
- cxa_atexit_p cxa_atexit_f;
- /* &__cxa_finalize; set if atexit_status >= atexit_status_broken. */
- cxa_finalize_p cxa_finalize_f;
- /* &atexit; set if atexit_status >= atexit_status_working
- or atexit_status == atexit_status_missing. */
- atexit_p atexit_f;
- };
- /* Return 0 if __cxa_atexit has the bug it has in Mac OS 10.4: it
- fails to call routines registered while an atexit routine is
- running. Return 1 if it works properly, and -1 if an error occurred. */
- struct atexit_data
- {
- int result;
- cxa_atexit_p cxa_atexit;
- };
- static void cxa_atexit_check_2 (void *arg)
- {
- ((struct atexit_data *)arg)->result = 1;
- }
- static void cxa_atexit_check_1 (void *arg)
- {
- struct atexit_data * aed = arg;
- if (aed->cxa_atexit (cxa_atexit_check_2, arg, arg) != 0)
- aed->result = -1;
- }
- static int
- check_cxa_atexit (cxa_atexit_p cxa_atexit, cxa_finalize_p cxa_finalize)
- {
- struct atexit_data aed = { 0, cxa_atexit };
- /* We re-use &aed as the 'dso' parameter, since it's a unique address. */
- if (cxa_atexit (cxa_atexit_check_1, &aed, &aed) != 0)
- return -1;
- cxa_finalize (&aed);
- if (aed.result == 0)
- {
- /* Call __cxa_finalize again to make sure that cxa_atexit_check_2
- is removed from the list before AED goes out of scope. */
- cxa_finalize (&aed);
- aed.result = 0;
- }
- return aed.result;
- }
- #ifdef __ppc__
- /* This comes from Csu. It works only before 10.4. The prototype has
- been altered a bit to avoid casting. */
- extern int _dyld_func_lookup(const char *dyld_func_name,
- void *address) __attribute__((visibility("hidden")));
- static void our_atexit (void);
- /* We're running on 10.3.9. Find the address of the system atexit()
- function. So easy to say, so hard to do. */
- static atexit_p
- find_atexit_10_3 (void)
- {
- unsigned int (*dyld_image_count_fn)(void);
- const char *(*dyld_get_image_name_fn)(unsigned int image_index);
- const void *(*dyld_get_image_header_fn)(unsigned int image_index);
- const void *(*NSLookupSymbolInImage_fn)(const void *image,
- const char *symbolName,
- unsigned int options);
- void *(*NSAddressOfSymbol_fn)(const void *symbol);
- unsigned i, count;
-
- /* Find some dyld functions. */
- _dyld_func_lookup("__dyld_image_count", &dyld_image_count_fn);
- _dyld_func_lookup("__dyld_get_image_name", &dyld_get_image_name_fn);
- _dyld_func_lookup("__dyld_get_image_header", &dyld_get_image_header_fn);
- _dyld_func_lookup("__dyld_NSLookupSymbolInImage", &NSLookupSymbolInImage_fn);
- _dyld_func_lookup("__dyld_NSAddressOfSymbol", &NSAddressOfSymbol_fn);
- /* If any of these don't exist, that's an error. */
- if (! dyld_image_count_fn || ! dyld_get_image_name_fn
- || ! dyld_get_image_header_fn || ! NSLookupSymbolInImage_fn
- || ! NSAddressOfSymbol_fn)
- return NULL;
-
- count = dyld_image_count_fn ();
- for (i = 0; i < count; i++)
- {
- const char * path = dyld_get_image_name_fn (i);
- const void * image;
- const void * symbol;
-
- if (strcmp (path, "/usr/lib/libSystem.B.dylib") != 0)
- continue;
- image = dyld_get_image_header_fn (i);
- if (! image)
- return NULL;
- /* '4' is NSLOOKUPSYMBOLINIMAGE_OPTION_RETURN_ON_ERROR. */
- symbol = NSLookupSymbolInImage_fn (image, "_atexit", 4);
- if (! symbol)
- return NULL;
- return NSAddressOfSymbol_fn (symbol);
- }
- return NULL;
- }
- #endif
- /* Create (if necessary), find, lock, fill in, and return our globals.
- Return NULL on error, in which case the globals will not be locked.
- The caller should call keymgr_set_and_unlock. */
- static struct keymgr_atexit_list *
- get_globals (void)
- {
- struct keymgr_atexit_list * r;
-
- #ifdef __ppc__
- /* 10.3.9 doesn't have _keymgr_get_and_lock_processwide_ptr_2 so the
- PPC side can't use it. On 10.4 this just means the error gets
- reported a little later when
- _keymgr_set_and_unlock_processwide_ptr finds that the key was
- never locked. */
- r = _keymgr_get_and_lock_processwide_ptr (KEYMGR_ATEXIT_LIST);
- #else
- void * rr;
- if (_keymgr_get_and_lock_processwide_ptr_2 (KEYMGR_ATEXIT_LIST, &rr))
- return NULL;
- r = rr;
- #endif
-
- if (r == NULL)
- {
- r = calloc (sizeof (struct keymgr_atexit_list), 1);
- if (! r)
- return NULL;
- }
- if (r->atexit_status == atexit_status_unknown)
- {
- void *handle;
- handle = dlopen ("/usr/lib/libSystem.B.dylib", RTLD_NOLOAD);
- if (!handle)
- {
- #ifdef __ppc__
- r->atexit_status = atexit_status_missing;
- r->atexit_f = find_atexit_10_3 ();
- if (! r->atexit_f)
- goto error;
- if (r->atexit_f (our_atexit))
- goto error;
- #else
- goto error;
- #endif
- }
- else
- {
- int chk_result;
- r->cxa_atexit_f = (cxa_atexit_p)dlsym (handle, "__cxa_atexit");
- r->cxa_finalize_f = (cxa_finalize_p)dlsym (handle, "__cxa_finalize");
- if (! r->cxa_atexit_f || ! r->cxa_finalize_f)
- goto error;
- chk_result = check_cxa_atexit (r->cxa_atexit_f, r->cxa_finalize_f);
- if (chk_result == -1)
- goto error;
- else if (chk_result == 0)
- r->atexit_status = atexit_status_broken;
- else
- {
- r->atexit_f = (atexit_p)dlsym (handle, "atexit");
- if (! r->atexit_f)
- goto error;
- r->atexit_status = atexit_status_working;
- }
- }
- }
- return r;
-
- error:
- _keymgr_set_and_unlock_processwide_ptr (KEYMGR_ATEXIT_LIST, r);
- return NULL;
- }
- /* Add TO_ADD to ATEXIT_LIST. ATEXIT_LIST may be NULL but is
- always the result of calling _keymgr_get_and_lock_processwide_ptr and
- so KEYMGR_ATEXIT_LIST is known to be locked; this routine is responsible
- for unlocking it. */
- static int
- add_routine (struct keymgr_atexit_list * g,
- const struct one_atexit_routine * to_add)
- {
- struct atexit_routine_list * s
- = malloc (sizeof (struct atexit_routine_list));
- int result;
-
- if (!s)
- {
- _keymgr_set_and_unlock_processwide_ptr (KEYMGR_ATEXIT_LIST, g);
- return -1;
- }
- s->r = *to_add;
- s->next = g->l;
- g->l = s;
- result = _keymgr_set_and_unlock_processwide_ptr (KEYMGR_ATEXIT_LIST, g);
- return CHECK_KEYMGR_ERROR (result) == 0 ? 0 : -1;
- }
- /* This runs the routines in G->L up to STOP. */
- static struct keymgr_atexit_list *
- run_routines (struct keymgr_atexit_list *g,
- struct atexit_routine_list *stop)
- {
- for (;;)
- {
- struct atexit_routine_list * cur = g->l;
- if (! cur || cur == stop)
- break;
- g->l = cur->next;
- _keymgr_set_and_unlock_processwide_ptr (KEYMGR_ATEXIT_LIST, g);
- switch (cur->r.has_arg) {
- case 0: case 2: case 4:
- cur->r.callback.ac ();
- break;
- case 1: case 3: case 5:
- cur->r.callback.cac (cur->r.arg);
- break;
- default:
- /* Don't understand, so don't call it. */
- break;
- }
- free (cur);
- g = _keymgr_get_and_lock_processwide_ptr (KEYMGR_ATEXIT_LIST);
- if (! g)
- break;
- }
- return g;
- }
- /* Call the routine described by ROUTINE_PARAM and then call any
- routines added to KEYMGR_ATEXIT_LIST while that routine was
- running, all with in_cxa_finalize set. */
- static void
- cxa_atexit_wrapper (void* routine_param)
- {
- struct one_atexit_routine * routine = routine_param;
- struct keymgr_atexit_list *g;
- struct atexit_routine_list * base = NULL;
- char prev_running = 0;
-
- g = _keymgr_get_and_lock_processwide_ptr (KEYMGR_ATEXIT_LIST);
- if (g)
- {
- prev_running = g->running_routines;
- g->running_routines = 1;
- base = g->l;
- _keymgr_set_and_unlock_processwide_ptr (KEYMGR_ATEXIT_LIST, g);
- }
- if (routine->has_arg)
- routine->callback.cac (routine->arg);
- else
- routine->callback.ac ();
- if (g)
- g = _keymgr_get_and_lock_processwide_ptr (KEYMGR_ATEXIT_LIST);
- if (g)
- g = run_routines (g, base);
- if (g)
- {
- g->running_routines = prev_running;
- _keymgr_set_and_unlock_processwide_ptr (KEYMGR_ATEXIT_LIST, g);
- }
- }
- #ifdef __ppc__
- /* This code is used while running on 10.3.9, when __cxa_atexit doesn't
- exist in the system library. 10.3.9 only supported regular PowerPC,
- so this code isn't necessary on x86 or ppc64. */
- /* This routine is called from the system atexit(); it runs everything
- registered on the KEYMGR_ATEXIT_LIST. */
- static void
- our_atexit (void)
- {
- struct keymgr_atexit_list *g;
- char prev_running;
- g = _keymgr_get_and_lock_processwide_ptr (KEYMGR_ATEXIT_LIST);
- if (! g || g->version != 0 || g->atexit_status != atexit_status_missing)
- return;
-
- prev_running = g->running_routines;
- g->running_routines = 1;
- g = run_routines (g, NULL);
- if (! g)
- return;
- g->running_routines = prev_running;
- _keymgr_set_and_unlock_processwide_ptr (KEYMGR_ATEXIT_LIST, g);
- }
- #endif
- /* This is our wrapper around atexit and __cxa_atexit. It will return
- nonzero if an error occurs, and otherwise:
- - if in_cxa_finalize is set, or running on 10.3.9, add R to
- KEYMGR_ATEXIT_LIST; or
- - call the system __cxa_atexit to add cxa_atexit_wrapper with an argument
- that indicates how cxa_atexit_wrapper should call R. */
- static int
- atexit_common (const struct one_atexit_routine *r, const void *dso)
- {
- struct keymgr_atexit_list *g = get_globals ();
- if (! g)
- return -1;
-
- if (g->running_routines || g->atexit_status == atexit_status_missing)
- return add_routine (g, r);
- if (g->atexit_status >= atexit_status_working)
- {
- int result;
- if (r->has_arg)
- {
- cxa_atexit_p cxa_atexit = g->cxa_atexit_f;
- result = _keymgr_set_and_unlock_processwide_ptr (KEYMGR_ATEXIT_LIST,
- g);
- if (CHECK_KEYMGR_ERROR (result))
- return -1;
- return cxa_atexit (r->callback.cac, r->arg, dso);
- }
- else
- {
- atexit_p atexit_f = g->atexit_f;
- result = _keymgr_set_and_unlock_processwide_ptr (KEYMGR_ATEXIT_LIST,
- g);
- if (CHECK_KEYMGR_ERROR (result))
- return -1;
- return atexit_f (r->callback.ac);
- }
- }
- else
- {
- cxa_atexit_p cxa_atexit = g->cxa_atexit_f;
- struct one_atexit_routine *alloced;
- int result;
- result = _keymgr_set_and_unlock_processwide_ptr (KEYMGR_ATEXIT_LIST, g);
- if (CHECK_KEYMGR_ERROR (result))
- return -1;
- alloced = malloc (sizeof (struct one_atexit_routine));
- if (! alloced)
- return -1;
- *alloced = *r;
- return cxa_atexit (cxa_atexit_wrapper, alloced, dso);
- }
- }
- /* These are the actual replacement routines; they just funnel into
- atexit_common. */
- int __cxa_atexit (cxa_atexit_callback func, void* arg,
- const void* dso) __attribute__((visibility("hidden")));
- int
- __cxa_atexit (cxa_atexit_callback func, void* arg, const void* dso)
- {
- struct one_atexit_routine r;
- r.callback.cac = func;
- r.has_arg = 1;
- r.arg = arg;
- return atexit_common (&r, dso);
- }
- int atexit (atexit_callback func) __attribute__((visibility("hidden")));
- /* Use __dso_handle to allow even bundles that call atexit() to be unloaded
- on 10.4. */
- extern void __dso_handle;
- int
- atexit (atexit_callback func)
- {
- struct one_atexit_routine r;
- r.callback.ac = func;
- r.has_arg = 0;
- return atexit_common (&r, &__dso_handle);
- }
- #endif /* __PIC__ */
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