1 /* Copyright (C) 2005, 2007, 2008 Red Hat, Inc.
2 This file is part of elfutils.
3 Written by Ulrich Drepper <drepper@redhat.com>, 2005.
4
5 This file is free software; you can redistribute it and/or modify
6 it under the terms of either
7
8 * the GNU Lesser General Public License as published by the Free
9 Software Foundation; either version 3 of the License, or (at
10 your option) any later version
11
12 or
13
14 * the GNU General Public License as published by the Free
15 Software Foundation; either version 2 of the License, or (at
16 your option) any later version
17
18 or both in parallel, as here.
19
20 elfutils is distributed in the hope that it will be useful, but
21 WITHOUT ANY WARRANTY; without even the implied warranty of
22 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
23 General Public License for more details.
24
25 You should have received copies of the GNU General Public License and
26 the GNU Lesser General Public License along with this program. If
27 not, see <http://www.gnu.org/licenses/>. */
28
29 #ifdef HAVE_CONFIG_H
30 # include <config.h>
31 #endif
32
33 #include <string.h>
34
35 #include "libasmP.h"
36 #include "../libebl/libeblP.h"
37
38
39 struct symtoken
40 {
41 DisasmCtx_t *ctx;
42 void *symcbarg;
43 };
44
45
46 static int
default_elf_getsym(GElf_Addr addr,Elf32_Word scnndx,GElf_Addr value,char ** buf,size_t * buflen,void * arg)47 default_elf_getsym (GElf_Addr addr, Elf32_Word scnndx, GElf_Addr value,
48 char **buf, size_t *buflen, void *arg)
49 {
50 struct symtoken *symtoken = (struct symtoken *) arg;
51
52 /* First try the user provided function. */
53 if (symtoken->ctx->symcb != NULL)
54 {
55 int res = symtoken->ctx->symcb (addr, scnndx, value, buf, buflen,
56 symtoken->symcbarg);
57 if (res >= 0)
58 return res;
59 }
60
61 // XXX Look up in ELF file.
62
63 return -1;
64 }
65
66
67 struct symaddrpair
68 {
69 GElf_Addr addr;
70 const char *name;
71 };
72
73
74 static void
read_symtab_exec(DisasmCtx_t * ctx)75 read_symtab_exec (DisasmCtx_t *ctx)
76 {
77 /* We simply use all we can get our hands on. This will produce
78 some duplicate information but this is no problem, we simply
79 ignore the latter definitions. */
80 Elf_Scn *scn= NULL;
81 while ((scn = elf_nextscn (ctx->elf, scn)) != NULL)
82 {
83 GElf_Shdr shdr_mem;
84 GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
85 Elf_Data *data;
86 if (shdr == NULL || shdr->sh_type != SHT_SYMTAB
87 || (data = elf_getdata (scn, NULL)) == NULL)
88 continue;
89
90 int xndxscnidx = elf_scnshndx (scn);
91 Elf_Data *xndxdata = NULL;
92 if (xndxscnidx > 0)
93 xndxdata = elf_getdata (elf_getscn (ctx->elf, xndxscnidx), NULL);
94
95 /* Iterate over all symbols. Add all defined symbols. */
96 int nsyms = shdr->sh_size / shdr->sh_entsize;
97 for (int cnt = 1; cnt < nsyms; ++cnt)
98 {
99 Elf32_Word xshndx;
100 GElf_Sym sym_mem;
101 GElf_Sym *sym = gelf_getsymshndx (data, xndxdata, cnt, &sym_mem,
102 &xshndx);
103 if (sym == NULL)
104 continue;
105
106 /* Undefined symbols are useless here. */
107 if (sym->st_shndx == SHN_UNDEF)
108 continue;
109
110
111 }
112 }
113 }
114
115
116 static void
read_symtab(DisasmCtx_t * ctx)117 read_symtab (DisasmCtx_t *ctx)
118 {
119 /* Find the symbol table(s). */
120 GElf_Ehdr ehdr_mem;
121 GElf_Ehdr *ehdr = gelf_getehdr (ctx->elf, &ehdr_mem);
122 if (ehdr == NULL)
123 return;
124
125 switch (ehdr->e_type)
126 {
127 case ET_EXEC:
128 case ET_DYN:
129 read_symtab_exec (ctx);
130 break;
131
132 case ET_REL:
133 // XXX Handle
134 break;
135
136 default:
137 break;
138 }
139 }
140
141
142 static int
null_elf_getsym(GElf_Addr addr,Elf32_Word scnndx,GElf_Addr value,char ** buf,size_t * buflen,void * arg)143 null_elf_getsym (GElf_Addr addr __attribute__ ((unused)),
144 Elf32_Word scnndx __attribute__ ((unused)),
145 GElf_Addr value __attribute__ ((unused)),
146 char **buf __attribute__ ((unused)),
147 size_t *buflen __attribute__ ((unused)),
148 void *arg __attribute__ ((unused)))
149 {
150 return -1;
151 }
152
153
154 int
disasm_cb(DisasmCtx_t * ctx,const uint8_t ** startp,const uint8_t * end,GElf_Addr addr,const char * fmt,DisasmOutputCB_t outcb,void * outcbarg,void * symcbarg)155 disasm_cb (DisasmCtx_t *ctx, const uint8_t **startp, const uint8_t *end,
156 GElf_Addr addr, const char *fmt, DisasmOutputCB_t outcb,
157 void *outcbarg, void *symcbarg)
158 {
159 struct symtoken symtoken;
160 DisasmGetSymCB_t getsym = ctx->symcb ?: null_elf_getsym;
161
162 if (ctx->elf != NULL)
163 {
164 /* Read all symbols of the ELF file and stuff them into a hash
165 table. The key is the address and the section index. */
166 read_symtab (ctx);
167
168 symtoken.ctx = ctx;
169 symtoken.symcbarg = symcbarg;
170
171 symcbarg = &symtoken;
172
173 getsym = default_elf_getsym;
174 }
175
176 return ctx->ebl->disasm (startp, end, addr, fmt, outcb, getsym, outcbarg,
177 symcbarg);
178 }
179 INTDEF (disasm_cb)
180