summaryrefslogtreecommitdiffstats
path: root/disas.c
blob: 81ba50a964846eba026756e82543fcd45426c79a (plain)
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
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
/* General "disassemble this chunk" code.  Used for debugging. */
#include "config.h"
#include "dis-asm.h"
#include "disas.h"
#include "elf.h"
#include <errno.h>

/* Filled in by elfload.c.  Simplistic, but will do for now. */
unsigned int disas_num_syms;
void *disas_symtab;
const char *disas_strtab;

/* Get LENGTH bytes from info's buffer, at target address memaddr.
   Transfer them to myaddr.  */
int
buffer_read_memory (memaddr, myaddr, length, info)
     bfd_vma memaddr;
     bfd_byte *myaddr;
     int length;
     struct disassemble_info *info;
{
  if (memaddr < info->buffer_vma
      || memaddr + length > info->buffer_vma + info->buffer_length)
    /* Out of bounds.  Use EIO because GDB uses it.  */
    return EIO;
  memcpy (myaddr, info->buffer + (memaddr - info->buffer_vma), length);
  return 0;
}

/* Print an error message.  We can assume that this is in response to
   an error return from buffer_read_memory.  */
void
perror_memory (status, memaddr, info)
     int status;
     bfd_vma memaddr;
     struct disassemble_info *info;
{
  if (status != EIO)
    /* Can't happen.  */
    (*info->fprintf_func) (info->stream, "Unknown error %d\n", status);
  else
    /* Actually, address between memaddr and memaddr + len was
       out of bounds.  */
    (*info->fprintf_func) (info->stream,
			   "Address 0x%llx is out of bounds.\n", memaddr);
}

/* This could be in a separate file, to save miniscule amounts of space
   in statically linked executables.  */

/* Just print the address is hex.  This is included for completeness even
   though both GDB and objdump provide their own (to print symbolic
   addresses).  */

void
generic_print_address (addr, info)
     bfd_vma addr;
     struct disassemble_info *info;
{
  (*info->fprintf_func) (info->stream, "0x%llx", addr);
}

/* Just return the given address.  */

int
generic_symbol_at_address (addr, info)
     bfd_vma addr;
     struct disassemble_info * info;
{
  return 1;
}

bfd_vma bfd_getl32 (const bfd_byte *addr)
{
  unsigned long v;

  v = (unsigned long) addr[0];
  v |= (unsigned long) addr[1] << 8;
  v |= (unsigned long) addr[2] << 16;
  v |= (unsigned long) addr[3] << 24;
  return (bfd_vma) v;
}

bfd_vma bfd_getb32 (const bfd_byte *addr)
{
  unsigned long v;

  v = (unsigned long) addr[0] << 24;
  v |= (unsigned long) addr[1] << 16;
  v |= (unsigned long) addr[2] << 8;
  v |= (unsigned long) addr[3];
  return (bfd_vma) v;
}

/* Disassemble this for me please... (debugging). 'flags' is only used
   for i386: non zero means 16 bit code */
void disas(FILE *out, void *code, unsigned long size, int is_host, int flags)
{
    uint8_t *pc;
    int count;
    struct disassemble_info disasm_info;
    int (*print_insn)(bfd_vma pc, disassemble_info *info);

    INIT_DISASSEMBLE_INFO(disasm_info, out, fprintf);

    disasm_info.buffer = code;
    disasm_info.buffer_vma = (unsigned long)code;
    disasm_info.buffer_length = size;

    if (is_host) {
#ifdef WORDS_BIGENDIAN
	disasm_info.endian = BFD_ENDIAN_BIG;
#else
	disasm_info.endian = BFD_ENDIAN_LITTLE;
#endif
#ifdef __i386__
	disasm_info.mach = bfd_mach_i386_i386;
	print_insn = print_insn_i386;
#elif defined(__powerpc__)
	print_insn = print_insn_ppc;
#elif defined(__alpha__)
	print_insn = print_insn_alpha;
#elif defined(__sparc__)
	print_insn = print_insn_sparc;
#elif defined(__arm__) 
        print_insn = print_insn_arm;
#else
	fprintf(out, "Asm output not supported on this arch\n");
	return;
#endif
    } else {
#ifdef TARGET_WORDS_BIGENDIAN
	disasm_info.endian = BFD_ENDIAN_BIG;
#else
	disasm_info.endian = BFD_ENDIAN_LITTLE;
#endif
#if defined(TARGET_I386)
        if (!flags)
	    disasm_info.mach = bfd_mach_i386_i386;
	else
	    disasm_info.mach = bfd_mach_i386_i8086;
	print_insn = print_insn_i386;
#elif defined(TARGET_ARM)
	print_insn = print_insn_arm;
#elif defined(TARGET_SPARC)
	print_insn = print_insn_sparc;
#else
	fprintf(out, "Asm output not supported on this arch\n");
	return;
#endif
    }

    for (pc = code; pc < (uint8_t *)code + size; pc += count) {
	fprintf(out, "0x%08lx:  ", (long)pc);
#ifdef __arm__
        /* since data are included in the code, it is better to
           display code data too */
        if (is_host) {
            fprintf(out, "%08x  ", (int)bfd_getl32((const bfd_byte *)pc));
        }
#endif
	count = print_insn((unsigned long)pc, &disasm_info);
	fprintf(out, "\n");
	if (count < 0)
	    break;
    }
}

/* Look up symbol for debugging purpose.  Returns "" if unknown. */
const char *lookup_symbol(void *orig_addr)
{
    unsigned int i;
    /* Hack, because we know this is x86. */
    Elf32_Sym *sym = disas_symtab;

    for (i = 0; i < disas_num_syms; i++) {
	if (sym[i].st_shndx == SHN_UNDEF
	    || sym[i].st_shndx >= SHN_LORESERVE)
	    continue;

	if (ELF_ST_TYPE(sym[i].st_info) != STT_FUNC)
	    continue;

	if ((long)orig_addr >= sym[i].st_value
	    && (long)orig_addr < sym[i].st_value + sym[i].st_size)
	    return disas_strtab + sym[i].st_name;
    }
    return "";
}
OpenPOWER on IntegriCloud