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
41 typedef int __gthread_mutex_t;
42 #define __gthread_mutex_lock(x) (void)(x)
43 #define __gthread_mutex_unlock(x) (void)(x)
44
45 static 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
56 extern void *_keymgr_get_and_lock_processwide_ptr (int);
57 extern void _keymgr_set_and_unlock_processwide_ptr (int, void *);
58 extern void _keymgr_unlock_processwide_ptr (int);
59
60 struct mach_header;
61 struct mach_header_64;
62 extern char *getsectdatafromheader (struct mach_header*, const char*,
63 const char *, unsigned long *);
64 extern char *getsectdatafromheader_64 (struct mach_header_64*, const char*,
65 const char *, unsigned long *);
66
67 /* This is referenced from KEYMGR_GCC3_DW2_OBJ_LIST. */
68 struct 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. */
75 struct 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. */
88 enum {
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
106 static void
live_image_destructor(struct live_images * image)107 live_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
144 static inline const fde *
examine_objects(void * pc,struct dwarf_eh_bases * bases,int dont_alloc)145 examine_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 = NULL;
156 unsigned long sz;
157
158 /* For ppc only check whether or not we have __DATA eh frames. */
159 #ifdef __ppc__
160 fde = getsectdatafromheader (image->mh, "__DATA", "__eh_frame", &sz);
161 #endif
162
163 if (fde == NULL)
164 {
165 #if __LP64__
166 fde = getsectdatafromheader_64 ((struct mach_header_64 *) image->mh,
167 "__TEXT", "__eh_frame", &sz);
168 #else
169 fde = getsectdatafromheader (image->mh, "__TEXT",
170 "__eh_frame", &sz);
171 #endif
172 if (fde != NULL)
173 image->examined_p |= IMAGE_IS_TEXT_MASK;
174 }
175
176 /* If .eh_frame is empty, don't register at all. */
177 if (fde != NULL && sz > 0)
178 {
179 char *real_fde = (fde + image->vm_slide);
180 struct object *ob = NULL;
181 struct object panicob;
182
183 if (! dont_alloc)
184 ob = calloc (1, sizeof (struct object));
185 dont_alloc |= ob == NULL;
186 if (dont_alloc)
187 ob = &panicob;
188
189 ob->pc_begin = (void *)-1;
190 ob->tbase = 0;
191 ob->dbase = 0;
192 ob->u.single = (struct dwarf_fde *)real_fde;
193 ob->s.i = 0;
194 ob->s.b.encoding = DW_EH_PE_omit;
195 ob->fde_end = real_fde + sz;
196
197 image->fde = real_fde;
198
199 result = search_object (ob, pc);
200
201 if (! dont_alloc)
202 {
203 struct object **p;
204
205 image->destructor = live_image_destructor;
206 image->object_info = ob;
207
208 image->examined_p |= (EXAMINED_IMAGE_MASK
209 | DESTRUCTOR_MAY_BE_CALLED_LIVE);
210
211 /* Insert the object into the classified list. */
212 for (p = &seen_objects; *p ; p = &(*p)->next)
213 if ((*p)->pc_begin < ob->pc_begin)
214 break;
215 ob->next = *p;
216 *p = ob;
217 }
218
219 if (result)
220 {
221 int encoding;
222 _Unwind_Ptr func;
223
224 bases->tbase = ob->tbase;
225 bases->dbase = ob->dbase;
226
227 encoding = ob->s.b.encoding;
228 if (ob->s.b.mixed_encoding)
229 encoding = get_fde_encoding (result);
230 read_encoded_value_with_base (encoding,
231 base_from_object (encoding, ob),
232 result->pc_begin, &func);
233 bases->func = (void *) func;
234 break;
235 }
236 }
237 else
238 image->examined_p |= EXAMINED_IMAGE_MASK;
239 }
240
241 _keymgr_unlock_processwide_ptr (KEYMGR_GCC3_LIVE_IMAGE_LIST);
242
243 return result;
244 }
245
246 const fde *
_Unwind_Find_FDE(void * pc,struct dwarf_eh_bases * bases)247 _Unwind_Find_FDE (void *pc, struct dwarf_eh_bases *bases)
248 {
249 struct km_object_info *the_obj_info;
250 const fde *ret = NULL;
251
252 the_obj_info =
253 _keymgr_get_and_lock_processwide_ptr (KEYMGR_GCC3_DW2_OBJ_LIST);
254 if (! the_obj_info)
255 the_obj_info = calloc (1, sizeof (*the_obj_info));
256
257 if (the_obj_info != NULL)
258 {
259 seen_objects = the_obj_info->seen_objects;
260 unseen_objects = the_obj_info->unseen_objects;
261
262 ret = _Unwind_Find_registered_FDE (pc, bases);
263 }
264
265 /* OK, didn't find it in the list of FDEs we've seen before,
266 so go through and look at the new ones. */
267 if (ret == NULL)
268 ret = examine_objects (pc, bases, the_obj_info == NULL);
269
270 if (the_obj_info != NULL)
271 {
272 the_obj_info->seen_objects = seen_objects;
273 the_obj_info->unseen_objects = unseen_objects;
274 }
275 _keymgr_set_and_unlock_processwide_ptr (KEYMGR_GCC3_DW2_OBJ_LIST,
276 the_obj_info);
277 return ret;
278 }
279