1/* Copyright (C) 2001, 2002, 2003, 2005 Free Software Foundation, Inc.
2
3   This file is part of GCC.
4
5   GCC is free software; you can redistribute it and/or modify
6   it under the terms of the GNU General Public License as published by
7   the Free Software Foundation; either version 2, or (at your option)
8   any later version.
9
10   GCC 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
13   GNU General Public License for more details.
14
15   You should have received a copy of the GNU General Public License
16   along with GCC; see the file COPYING.  If not, write to
17   the Free Software Foundation, 51 Franklin Street, Fifth Floor,
18   Boston, MA 02110-1301, USA.  */
19
20/* As a special exception, if you link this library with other files,
21   some of which are compiled with GCC, to produce an executable,
22   this library does not by itself cause the resulting executable
23   to be covered by the GNU General Public License.
24   This exception does not however invalidate any other reasons why
25   the executable file might be covered by the GNU General Public License.  */
26
27/* Locate the FDE entry for a given address, using Darwin's keymgr support.  */
28
29#include "tconfig.h"
30#include "tsystem.h"
31#include <string.h>
32#include <stdlib.h>
33#include "dwarf2.h"
34#include "unwind.h"
35#define NO_BASE_OF_ENCODED_VALUE
36#define DWARF2_OBJECT_END_PTR_EXTENSION
37#include "unwind-pe.h"
38#include "unwind-dw2-fde.h"
39/* Carefully don't include gthr.h.  */
40
41typedef int __gthread_mutex_t;
42#define __gthread_mutex_lock(x)  (void)(x)
43#define __gthread_mutex_unlock(x) (void)(x)
44
45static const fde * _Unwind_Find_registered_FDE (void *pc,
46						struct dwarf_eh_bases *bases);
47
48#define _Unwind_Find_FDE _Unwind_Find_registered_FDE
49#include "unwind-dw2-fde.c"
50#undef _Unwind_Find_FDE
51
52/* KeyMgr stuff.  */
53#define KEYMGR_GCC3_LIVE_IMAGE_LIST     301     /* loaded images  */
54#define KEYMGR_GCC3_DW2_OBJ_LIST        302     /* Dwarf2 object list  */
55
56extern void *_keymgr_get_and_lock_processwide_ptr (int);
57extern void _keymgr_set_and_unlock_processwide_ptr (int, void *);
58extern void _keymgr_unlock_processwide_ptr (int);
59
60struct mach_header;
61struct mach_header_64;
62extern char *getsectdatafromheader (struct mach_header*, const char*,
63			const char *, unsigned long *);
64extern char *getsectdatafromheader_64 (struct mach_header*, const char*,
65			const char *, unsigned long *);
66
67/* This is referenced from KEYMGR_GCC3_DW2_OBJ_LIST.  */
68struct km_object_info {
69  struct object *seen_objects;
70  struct object *unseen_objects;
71  unsigned spare[2];
72};
73
74/* Node of KEYMGR_GCC3_LIVE_IMAGE_LIST.  Info about each resident image.  */
75struct live_images {
76  unsigned long this_size;                      /* sizeof (live_images)  */
77  struct mach_header *mh;                       /* the image info  */
78  unsigned long vm_slide;
79  void (*destructor)(struct live_images *);     /* destructor for this  */
80  struct live_images *next;
81  unsigned int examined_p;
82  void *fde;
83  void *object_info;
84  unsigned long info[2];                        /* Future use.  */
85};
86
87/* Bits in the examined_p field of struct live_images.  */
88enum {
89  EXAMINED_IMAGE_MASK = 1,	/* We've seen this one.  */
90  ALLOCED_IMAGE_MASK = 2,	/* The FDE entries were allocated by
91				   malloc, and must be freed.  This isn't
92				   used by newer libgcc versions.  */
93  IMAGE_IS_TEXT_MASK = 4,	/* This image is in the TEXT segment.  */
94  DESTRUCTOR_MAY_BE_CALLED_LIVE = 8  /* The destructor may be called on an
95					object that's part of the live
96					image list.  */
97};
98
99/* Delete any data we allocated on a live_images structure.  Either
100   IMAGE has already been removed from the
101   KEYMGR_GCC3_LIVE_IMAGE_LIST and the struct will be deleted
102   after we return, or that list is locked and we're being called
103   because this object might be about to be unloaded.  Called by
104   KeyMgr.  */
105
106static void
107live_image_destructor (struct live_images *image)
108{
109  if (image->object_info)
110    {
111      struct km_object_info *the_obj_info;
112
113      the_obj_info =
114	_keymgr_get_and_lock_processwide_ptr (KEYMGR_GCC3_DW2_OBJ_LIST);
115      if (the_obj_info)
116	{
117	  seen_objects = the_obj_info->seen_objects;
118	  unseen_objects = the_obj_info->unseen_objects;
119
120	  /* Free any sorted arrays.  */
121	  __deregister_frame_info_bases (image->fde);
122
123	  the_obj_info->seen_objects = seen_objects;
124	  the_obj_info->unseen_objects = unseen_objects;
125	}
126      _keymgr_set_and_unlock_processwide_ptr (KEYMGR_GCC3_DW2_OBJ_LIST,
127					      the_obj_info);
128
129      free (image->object_info);
130      image->object_info = NULL;
131      if (image->examined_p & ALLOCED_IMAGE_MASK)
132	free (image->fde);
133      image->fde = NULL;
134    }
135  image->examined_p = 0;
136  image->destructor = NULL;
137}
138
139/* Run through the list of live images.  If we can allocate memory,
140   give each unseen image a new `struct object'.  Even if we can't,
141   check whether the PC is inside the FDE of each unseen image.
142 */
143
144static inline const fde *
145examine_objects (void *pc, struct dwarf_eh_bases *bases, int dont_alloc)
146{
147  const fde *result = NULL;
148  struct live_images *image;
149
150  image = _keymgr_get_and_lock_processwide_ptr (KEYMGR_GCC3_LIVE_IMAGE_LIST);
151
152  for (; image != NULL; image = image->next)
153    if ((image->examined_p & EXAMINED_IMAGE_MASK) == 0)
154      {
155	char *fde;
156	unsigned long sz;
157
158#ifdef __ppc64__
159	fde = getsectdatafromheader_64 ((struct mach_header_64 *) image->mh,
160				     "__DATA", "__eh_frame", &sz);
161#else
162	fde = getsectdatafromheader (image->mh, "__DATA", "__eh_frame", &sz);
163#endif
164	if (fde == NULL)
165	  {
166#ifdef __ppc64__
167	    fde = getsectdatafromheader_64 ((struct mach_header_64 *) image->mh,
168					 "__TEXT", "__eh_frame", &sz);
169#else
170	    fde = getsectdatafromheader (image->mh, "__TEXT",
171					 "__eh_frame", &sz);
172#endif
173	    if (fde != NULL)
174	      image->examined_p |= IMAGE_IS_TEXT_MASK;
175	  }
176
177	/* If .eh_frame is empty, don't register at all.  */
178	if (fde != NULL && sz > 0)
179	  {
180	    char *real_fde = (fde + image->vm_slide);
181	    struct object *ob = NULL;
182	    struct object panicob;
183
184	    if (! dont_alloc)
185	      ob = calloc (1, sizeof (struct object));
186	    dont_alloc |= ob == NULL;
187	    if (dont_alloc)
188	      ob = &panicob;
189
190	    ob->pc_begin = (void *)-1;
191	    ob->tbase = 0;
192	    ob->dbase = 0;
193	    ob->u.single = (struct dwarf_fde *)real_fde;
194	    ob->s.i = 0;
195	    ob->s.b.encoding = DW_EH_PE_omit;
196	    ob->fde_end = real_fde + sz;
197
198	    image->fde = real_fde;
199
200	    result = search_object (ob, pc);
201
202	    if (! dont_alloc)
203	      {
204		struct object **p;
205
206		image->destructor = live_image_destructor;
207		image->object_info = ob;
208
209		image->examined_p |= (EXAMINED_IMAGE_MASK
210				      | DESTRUCTOR_MAY_BE_CALLED_LIVE);
211
212		/* Insert the object into the classified list.  */
213		for (p = &seen_objects; *p ; p = &(*p)->next)
214		  if ((*p)->pc_begin < ob->pc_begin)
215		    break;
216		ob->next = *p;
217		*p = ob;
218	      }
219
220	    if (result)
221	      {
222		int encoding;
223		_Unwind_Ptr func;
224
225		bases->tbase = ob->tbase;
226		bases->dbase = ob->dbase;
227
228		encoding = ob->s.b.encoding;
229		if (ob->s.b.mixed_encoding)
230		  encoding = get_fde_encoding (result);
231		read_encoded_value_with_base (encoding,
232					      base_from_object (encoding, ob),
233					      result->pc_begin, &func);
234		bases->func = (void *) func;
235		break;
236	      }
237	  }
238	else
239	  image->examined_p |= EXAMINED_IMAGE_MASK;
240      }
241
242  _keymgr_unlock_processwide_ptr (KEYMGR_GCC3_LIVE_IMAGE_LIST);
243
244  return result;
245}
246
247const fde *
248_Unwind_Find_FDE (void *pc, struct dwarf_eh_bases *bases)
249{
250  struct km_object_info *the_obj_info;
251  const fde *ret = NULL;
252
253  the_obj_info =
254    _keymgr_get_and_lock_processwide_ptr (KEYMGR_GCC3_DW2_OBJ_LIST);
255  if (! the_obj_info)
256    the_obj_info = calloc (1, sizeof (*the_obj_info));
257
258  if (the_obj_info != NULL)
259    {
260      seen_objects = the_obj_info->seen_objects;
261      unseen_objects = the_obj_info->unseen_objects;
262
263      ret = _Unwind_Find_registered_FDE (pc, bases);
264    }
265
266  /* OK, didn't find it in the list of FDEs we've seen before,
267     so go through and look at the new ones.  */
268  if (ret == NULL)
269    ret = examine_objects (pc, bases, the_obj_info == NULL);
270
271  if (the_obj_info != NULL)
272    {
273      the_obj_info->seen_objects = seen_objects;
274      the_obj_info->unseen_objects = unseen_objects;
275    }
276  _keymgr_set_and_unlock_processwide_ptr (KEYMGR_GCC3_DW2_OBJ_LIST,
277					  the_obj_info);
278  return ret;
279}
280