1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
|
/*
* Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
#include "precompiled.hpp"
#ifdef __APPLE__
#include "decoder_machO.hpp"
#include <cxxabi.h>
#include <mach-o/loader.h>
#include <mach-o/nlist.h>
bool MachODecoder::demangle(const char* symbol, char *buf, int buflen) {
int status;
char* result;
size_t size = (size_t)buflen;
// Don't pass buf to __cxa_demangle. In case of the 'buf' is too small,
// __cxa_demangle will call system "realloc" for additional memory, which
// may use different malloc/realloc mechanism that allocates 'buf'.
if ((result = abi::__cxa_demangle(symbol, NULL, NULL, &status)) != NULL) {
jio_snprintf(buf, buflen, "%s", result);
// call c library's free
::free(result);
return true;
}
return false;
}
bool MachODecoder::decode(address addr, char *buf,
int buflen, int *offset, const void *mach_base) {
struct symtab_command * symt = (struct symtab_command *)
mach_find_command((struct mach_header_64 *)mach_base, LC_SYMTAB);
if (symt == NULL) {
DEBUG_ONLY(tty->print_cr("no symtab in mach file at 0x%lx", mach_base));
return false;
}
uint32_t off = symt->symoff; /* symbol table offset (within this mach file) */
uint32_t nsyms = symt->nsyms; /* number of symbol table entries */
uint32_t stroff = symt->stroff; /* string table offset */
uint32_t strsize = symt->strsize; /* string table size in bytes */
// iterate through symbol table trying to match our offset
uint32_t addr_relative = (uintptr_t) mach_base - (uintptr_t) addr; // offset we seek in the symtab
void * symtab_addr = (void*) ((uintptr_t) mach_base + off);
struct nlist_64 *cur_nlist = (struct nlist_64 *) symtab_addr;
struct nlist_64 *last_nlist = cur_nlist; // no size stored in an entry, so keep previously seen nlist
int32_t found_strx = 0;
int32_t found_symval = 0;
for (uint32_t i=0; i < nsyms; i++) {
uint32_t this_value = cur_nlist->n_value;
if (addr_relative == this_value) {
found_strx = cur_nlist->n_un.n_strx;
found_symval = this_value;
break;
} else if (addr_relative > this_value) {
// gone past it, use previously seen nlist:
found_strx = last_nlist->n_un.n_strx;
found_symval = last_nlist->n_value;
break;
}
last_nlist = cur_nlist;
cur_nlist = cur_nlist + sizeof(struct nlist_64);
}
if (found_strx == 0) {
return false;
}
// write the offset:
*offset = addr_relative - found_symval;
// lookup found_strx in the string table
char * symname = mach_find_in_stringtable((char*) ((uintptr_t)mach_base + stroff), strsize, found_strx);
if (symname) {
strncpy(buf, symname, buflen);
return true;
}
DEBUG_ONLY(tty->print_cr("no string or null string found."));
return false;
}
void* MachODecoder::mach_find_command(struct mach_header_64 * mach_base, uint32_t command_wanted) {
// possibly verify it is a mach_header, use magic number.
// commands begin immediately after the header.
struct load_command *pos = (struct load_command *) mach_base + sizeof(struct mach_header_64);
for (uint32_t i = 0; i < mach_base->ncmds; i++) {
struct load_command *this_cmd = (struct load_command *) pos;
if (this_cmd->cmd == command_wanted) {
return pos;
}
int cmdsize = this_cmd->cmdsize;
pos += cmdsize;
}
return NULL;
}
char* MachODecoder::mach_find_in_stringtable(char *strtab, uint32_t tablesize, int strx_wanted) {
if (strx_wanted == 0) {
return NULL;
}
char *strtab_end = strtab + tablesize;
// find the first string, skip over the space char
// (or the four zero bytes we see e.g. in libclient)
if (*strtab == ' ') {
strtab++;
if (*strtab != 0) {
DEBUG_ONLY(tty->print_cr("string table has leading space but no following zero."));
return NULL;
}
strtab++;
} else {
if ((uint32_t) *strtab != 0) {
DEBUG_ONLY(tty->print_cr("string table without leading space or leading int of zero."));
return NULL;
}
strtab+=4;
}
// read the real strings starting at index 1
int cur_strx = 1;
while (strtab < strtab_end) {
if (cur_strx == strx_wanted) {
return strtab;
}
// find start of next string
while (*strtab != 0) {
strtab++;
}
strtab++; // skip the terminating zero
cur_strx++;
}
DEBUG_ONLY(tty->print_cr("string number %d not found.", strx_wanted));
return NULL;
}
#endif
|
