1 /* Copyright (C) 2001, 2002, 2003 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, 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, 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 <string.h>
31 #include <stdlib.h>
32 #include "dwarf2.h"
33 #include "unwind.h"
34 #define NO_BASE_OF_ENCODED_VALUE
35 #define DWARF2_OBJECT_END_PTR_EXTENSION
36 #include "unwind-pe.h"
37 #include "unwind-dw2-fde.h"
38 /* Carefully don't include gthr.h. */
39
40 typedef int __gthread_mutex_t;
41 #define __gthread_mutex_lock(x) (void)(x)
42 #define __gthread_mutex_unlock(x) (void)(x)
43
44 static const fde * _Unwind_Find_registered_FDE (void *pc,
45 struct dwarf_eh_bases *bases);
46
47 #define _Unwind_Find_FDE _Unwind_Find_registered_FDE
48 #include "unwind-dw2-fde.c"
49 #undef _Unwind_Find_FDE
50
51 /* KeyMgr stuff. */
52 #define KEYMGR_GCC3_LIVE_IMAGE_LIST 301 /* loaded images */
53 #define KEYMGR_GCC3_DW2_OBJ_LIST 302 /* Dwarf2 object list */
54
55 extern void *_keymgr_get_and_lock_processwide_ptr (int);
56 extern void _keymgr_set_and_unlock_processwide_ptr (int, void *);
57 extern void _keymgr_unlock_processwide_ptr (int);
58
59 struct mach_header;
60 extern char *getsectdatafromheader (struct mach_header*, const char*,
61 const char *, unsigned long *);
62
63 /* This is referenced from KEYMGR_GCC3_DW2_OBJ_LIST. */
64 struct km_object_info {
65 struct object *seen_objects;
66 struct object *unseen_objects;
67 unsigned spare[2];
68 };
69
70 /* Node of KEYMGR_GCC3_LIVE_IMAGE_LIST. Info about each resident image. */
71 struct live_images {
72 unsigned long this_size; /* sizeof (live_images) */
73 struct mach_header *mh; /* the image info */
74 unsigned long vm_slide;
75 void (*destructor)(struct live_images *); /* destructor for this */
76 struct live_images *next;
77 unsigned int examined_p;
78 void *fde;
79 void *object_info;
80 unsigned long info[2]; /* Future use. */
81 };
82
83 /* Bits in the examined_p field of struct live_images. */
84 enum {
85 EXAMINED_IMAGE_MASK = 1, /* We've seen this one. */
86 ALLOCED_IMAGE_MASK = 2, /* The FDE entries were allocated by
87 malloc, and must be freed. This isn't
88 used by newer libgcc versions. */
89 IMAGE_IS_TEXT_MASK = 4, /* This image is in the TEXT segment. */
90 DESTRUCTOR_MAY_BE_CALLED_LIVE = 8 /* The destructor may be called on an
91 object that's part of the live
92 image list. */
93 };
94
95 /* Delete any data we allocated on a live_images structure. Either
96 IMAGE has already been removed from the
97 KEYMGR_GCC3_LIVE_IMAGE_LIST and the struct will be deleted
98 after we return, or that list is locked and we're being called
99 because this object might be about to be unloaded. Called by
100 KeyMgr. */
101
102 static void
live_image_destructor(struct live_images * image)103 live_image_destructor (struct live_images *image)
104 {
105 if (image->object_info)
106 {
107 struct km_object_info *the_obj_info;
108
109 the_obj_info =
110 _keymgr_get_and_lock_processwide_ptr (KEYMGR_GCC3_DW2_OBJ_LIST);
111 if (the_obj_info)
112 {
113 seen_objects = the_obj_info->seen_objects;
114 unseen_objects = the_obj_info->unseen_objects;
115
116 /* Free any sorted arrays. */
117 __deregister_frame_info_bases (image->fde);
118
119 the_obj_info->seen_objects = seen_objects;
120 the_obj_info->unseen_objects = unseen_objects;
121 }
122 _keymgr_set_and_unlock_processwide_ptr (KEYMGR_GCC3_DW2_OBJ_LIST,
123 the_obj_info);
124
125 free (image->object_info);
126 image->object_info = NULL;
127 if (image->examined_p & ALLOCED_IMAGE_MASK)
128 free (image->fde);
129 image->fde = NULL;
130 }
131 image->examined_p = 0;
132 image->destructor = NULL;
133 }
134
135 /* Run through the list of live images. If we can allocate memory,
136 give each unseen image a new `struct object'. Even if we can't,
137 check whether the PC is inside the FDE of each unseen image.
138 */
139
140 static inline const fde *
examine_objects(void * pc,struct dwarf_eh_bases * bases,int dont_alloc)141 examine_objects (void *pc, struct dwarf_eh_bases *bases, int dont_alloc)
142 {
143 const fde *result = NULL;
144 struct live_images *image;
145
146 image = _keymgr_get_and_lock_processwide_ptr (KEYMGR_GCC3_LIVE_IMAGE_LIST);
147
148 for (; image != NULL; image = image->next)
149 if ((image->examined_p & EXAMINED_IMAGE_MASK) == 0)
150 {
151 char *fde;
152 unsigned long sz;
153
154 fde = getsectdatafromheader (image->mh, "__DATA", "__eh_frame", &sz);
155 if (fde == NULL)
156 {
157 fde = getsectdatafromheader (image->mh, "__TEXT",
158 "__eh_frame", &sz);
159 if (fde != NULL)
160 image->examined_p |= IMAGE_IS_TEXT_MASK;
161 }
162
163 /* If .eh_frame is empty, don't register at all. */
164 if (fde != NULL && sz > 0)
165 {
166 char *real_fde = (fde + image->vm_slide);
167 struct object *ob = NULL;
168 struct object panicob;
169
170 if (! dont_alloc)
171 ob = calloc (1, sizeof (struct object));
172 dont_alloc |= ob == NULL;
173 if (dont_alloc)
174 ob = &panicob;
175
176 ob->pc_begin = (void *)-1;
177 ob->tbase = 0;
178 ob->dbase = 0;
179 ob->u.single = (struct dwarf_fde *)real_fde;
180 ob->s.i = 0;
181 ob->s.b.encoding = DW_EH_PE_omit;
182 ob->fde_end = real_fde + sz;
183
184 image->fde = real_fde;
185
186 result = search_object (ob, pc);
187
188 if (! dont_alloc)
189 {
190 struct object **p;
191
192 image->destructor = live_image_destructor;
193 image->object_info = ob;
194
195 image->examined_p |= (EXAMINED_IMAGE_MASK
196 | DESTRUCTOR_MAY_BE_CALLED_LIVE);
197
198 /* Insert the object into the classified list. */
199 for (p = &seen_objects; *p ; p = &(*p)->next)
200 if ((*p)->pc_begin < ob->pc_begin)
201 break;
202 ob->next = *p;
203 *p = ob;
204 }
205
206 if (result)
207 {
208 int encoding;
209
210 bases->tbase = ob->tbase;
211 bases->dbase = ob->dbase;
212
213 encoding = ob->s.b.encoding;
214 if (ob->s.b.mixed_encoding)
215 encoding = get_fde_encoding (result);
216 read_encoded_value_with_base (encoding,
217 base_from_object (encoding, ob),
218 result->pc_begin,
219 (_Unwind_Ptr *)&bases->func);
220 break;
221 }
222 }
223 else
224 image->examined_p |= EXAMINED_IMAGE_MASK;
225 }
226
227 _keymgr_unlock_processwide_ptr (KEYMGR_GCC3_LIVE_IMAGE_LIST);
228
229 return result;
230 }
231
232 const fde *
_Unwind_Find_FDE(void * pc,struct dwarf_eh_bases * bases)233 _Unwind_Find_FDE (void *pc, struct dwarf_eh_bases *bases)
234 {
235 struct km_object_info *the_obj_info;
236 const fde *ret = NULL;
237
238 the_obj_info =
239 _keymgr_get_and_lock_processwide_ptr (KEYMGR_GCC3_DW2_OBJ_LIST);
240 if (! the_obj_info)
241 the_obj_info = calloc (1, sizeof (*the_obj_info));
242
243 if (the_obj_info != NULL)
244 {
245 seen_objects = the_obj_info->seen_objects;
246 unseen_objects = the_obj_info->unseen_objects;
247
248 ret = _Unwind_Find_registered_FDE (pc, bases);
249 }
250
251 /* OK, didn't find it in the list of FDEs we've seen before,
252 so go through and look at the new ones. */
253 if (ret == NULL)
254 ret = examine_objects (pc, bases, the_obj_info == NULL);
255
256 if (the_obj_info != NULL)
257 {
258 the_obj_info->seen_objects = seen_objects;
259 the_obj_info->unseen_objects = unseen_objects;
260 }
261 _keymgr_set_and_unlock_processwide_ptr (KEYMGR_GCC3_DW2_OBJ_LIST,
262 the_obj_info);
263 return ret;
264 }
265