1 /* Copyright (C) 2001, 2002 Free Software Foundation, Inc.
2
3 This file is part of GNU CC.
4
5 GNU CC 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 GNU CC 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 GNU CC; 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 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 /* Free any sorted arrays. */
108 __deregister_frame_info_bases (image->fde);
109
110 free (image->object_info);
111 image->object_info = NULL;
112 if (image->examined_p & ALLOCED_IMAGE_MASK)
113 free (image->fde);
114 image->fde = NULL;
115 }
116 image->examined_p = 0;
117 image->destructor = NULL;
118 }
119
120 /* Run through the list of live images. If we can allocate memory,
121 give each unseen image a new `struct object'. Even if we can't,
122 check whether the PC is inside the FDE of each unseen image.
123 */
124
125 static inline fde *
examine_objects(void * pc,struct dwarf_eh_bases * bases,int dont_alloc)126 examine_objects (void *pc, struct dwarf_eh_bases *bases, int dont_alloc)
127 {
128 fde *result = NULL;
129 struct live_images *image;
130
131 image = _keymgr_get_and_lock_processwide_ptr (KEYMGR_GCC3_LIVE_IMAGE_LIST);
132
133 for (; image != NULL; image = image->next)
134 if ((image->examined_p & EXAMINED_IMAGE_MASK) == 0)
135 {
136 char *fde;
137 unsigned long sz;
138
139 fde = getsectdatafromheader (image->mh, "__DATA", "__eh_frame", &sz);
140 if (fde == NULL)
141 {
142 fde = getsectdatafromheader (image->mh, "__TEXT",
143 "__eh_frame", &sz);
144 if (fde != NULL)
145 image->examined_p |= IMAGE_IS_TEXT_MASK;
146 }
147
148 /* If .eh_frame is empty, don't register at all. */
149 if (fde != NULL && sz > 0)
150 {
151 char *real_fde = (fde + image->vm_slide);
152 struct object *ob = NULL;
153 struct object panicob;
154
155 if (! dont_alloc)
156 ob = calloc (1, sizeof (struct object));
157 dont_alloc |= ob == NULL;
158 if (dont_alloc)
159 ob = &panicob;
160
161 ob->pc_begin = (void *)-1;
162 ob->tbase = 0;
163 ob->dbase = 0;
164 ob->u.single = (struct dwarf_fde *)real_fde;
165 ob->s.i = 0;
166 ob->s.b.encoding = DW_EH_PE_omit;
167 ob->fde_end = real_fde + sz;
168
169 if (! dont_alloc)
170 {
171 ob->next = unseen_objects;
172 unseen_objects = ob;
173
174 image->destructor = live_image_destructor;
175 image->object_info = ob;
176
177 image->examined_p |= (EXAMINED_IMAGE_MASK
178 | DESTRUCTOR_MAY_BE_CALLED_LIVE);
179 }
180 image->fde = real_fde;
181
182 result = search_object (ob, pc);
183 if (result)
184 {
185 int encoding;
186
187 bases->tbase = ob->tbase;
188 bases->dbase = ob->dbase;
189
190 encoding = ob->s.b.encoding;
191 if (ob->s.b.mixed_encoding)
192 encoding = get_fde_encoding (result);
193 read_encoded_value_with_base (encoding,
194 base_from_object (encoding, ob),
195 result->pc_begin,
196 (_Unwind_Ptr *)&bases->func);
197 break;
198 }
199 }
200 else
201 image->examined_p |= EXAMINED_IMAGE_MASK;
202 }
203
204 _keymgr_unlock_processwide_ptr (KEYMGR_GCC3_LIVE_IMAGE_LIST);
205
206 return result;
207 }
208
209 fde *
_Unwind_Find_FDE(void * pc,struct dwarf_eh_bases * bases)210 _Unwind_Find_FDE (void *pc, struct dwarf_eh_bases *bases)
211 {
212 struct km_object_info *the_obj_info;
213 fde *ret = NULL;
214
215 the_obj_info =
216 _keymgr_get_and_lock_processwide_ptr (KEYMGR_GCC3_DW2_OBJ_LIST);
217 if (! the_obj_info)
218 the_obj_info = calloc (1, sizeof (*the_obj_info));
219
220 if (the_obj_info != NULL)
221 {
222 seen_objects = the_obj_info->seen_objects;
223 unseen_objects = the_obj_info->unseen_objects;
224
225 ret = _Unwind_Find_registered_FDE (pc, bases);
226 }
227
228 /* OK, didn't find it in the list of FDEs we've seen before,
229 so go through and look at the new ones. */
230 if (ret == NULL)
231 ret = examine_objects (pc, bases, the_obj_info == NULL);
232
233 if (the_obj_info != NULL)
234 {
235 the_obj_info->seen_objects = seen_objects;
236 the_obj_info->unseen_objects = unseen_objects;
237 _keymgr_set_and_unlock_processwide_ptr (KEYMGR_GCC3_DW2_OBJ_LIST,
238 the_obj_info);
239 }
240 return ret;
241 }
242