| 1 | #include <stdio.h> |
| 2 | #include <stdlib.h> |
| 3 | #include <string.h> |
| 4 | #include <stdarg.h> |
| 5 | #include <bfd.h> |
| 6 | #include <dis-asm.h> |
| 7 | |
| 8 | #include "host_dasm.h" |
| 9 | |
| 10 | extern char **g_argv; |
| 11 | |
| 12 | static struct disassemble_info di; |
| 13 | |
| 14 | /* symbols */ |
| 15 | static asymbol **symbols; |
| 16 | static long symcount; |
| 17 | |
| 18 | /* Filter out (in place) symbols that are useless for disassembly. |
| 19 | COUNT is the number of elements in SYMBOLS. |
| 20 | Return the number of useful symbols. */ |
| 21 | static long |
| 22 | remove_useless_symbols (asymbol **symbols, long count) |
| 23 | { |
| 24 | asymbol **in_ptr = symbols, **out_ptr = symbols; |
| 25 | |
| 26 | while (--count >= 0) |
| 27 | { |
| 28 | asymbol *sym = *in_ptr++; |
| 29 | |
| 30 | if (sym->name == NULL || sym->name[0] == '\0') |
| 31 | continue; |
| 32 | if (sym->flags & (BSF_DEBUGGING | BSF_SECTION_SYM)) |
| 33 | continue; |
| 34 | if (bfd_is_und_section (sym->section) |
| 35 | || bfd_is_com_section (sym->section)) |
| 36 | continue; |
| 37 | if (sym->value + sym->section->vma == 0) |
| 38 | continue; |
| 39 | /* |
| 40 | printf("sym: %08lx %04x %08x v %08x \"%s\"\n", |
| 41 | (unsigned int)sym->value, (unsigned int)sym->flags, (unsigned int)sym->udata.i, |
| 42 | (unsigned int)sym->section->vma, sym->name); |
| 43 | */ |
| 44 | *out_ptr++ = sym; |
| 45 | } |
| 46 | return out_ptr - symbols; |
| 47 | } |
| 48 | |
| 49 | static void slurp_symtab(const char *filename) |
| 50 | { |
| 51 | bfd *abfd; |
| 52 | long storage; |
| 53 | |
| 54 | symcount = 0; |
| 55 | |
| 56 | abfd = bfd_openr(filename, NULL); |
| 57 | if (abfd == NULL) { |
| 58 | fprintf(stderr, "failed to open: %s\n", filename); |
| 59 | goto no_symbols; |
| 60 | } |
| 61 | |
| 62 | if (!bfd_check_format(abfd, bfd_object)) |
| 63 | goto no_symbols; |
| 64 | |
| 65 | if (!(bfd_get_file_flags(abfd) & HAS_SYMS)) |
| 66 | goto no_symbols; |
| 67 | |
| 68 | storage = bfd_get_symtab_upper_bound(abfd); |
| 69 | if (storage <= 0) |
| 70 | goto no_symbols; |
| 71 | |
| 72 | symbols = malloc(storage); |
| 73 | symcount = bfd_canonicalize_symtab(abfd, symbols); |
| 74 | if (symcount < 0) |
| 75 | goto no_symbols; |
| 76 | |
| 77 | symcount = remove_useless_symbols(symbols, symcount); |
| 78 | // bfd_close(abfd); |
| 79 | return; |
| 80 | |
| 81 | no_symbols: |
| 82 | fprintf(stderr, "no symbols in %s\n", bfd_get_filename(abfd)); |
| 83 | if (abfd != NULL) |
| 84 | bfd_close(abfd); |
| 85 | } |
| 86 | |
| 87 | |
| 88 | /* Like target_read_memory, but slightly different parameters. */ |
| 89 | static int |
| 90 | dis_asm_read_memory(bfd_vma memaddr, bfd_byte *myaddr, unsigned int len, |
| 91 | struct disassemble_info *info) |
| 92 | { |
| 93 | memcpy(myaddr, (void *)(int)memaddr, len); |
| 94 | return 0; |
| 95 | } |
| 96 | |
| 97 | static void |
| 98 | dis_asm_memory_error(int status, bfd_vma memaddr, |
| 99 | struct disassemble_info *info) |
| 100 | { |
| 101 | fprintf(stderr, "memory_error %p\n", (void *)(int)memaddr); |
| 102 | } |
| 103 | |
| 104 | static void |
| 105 | dis_asm_print_address(bfd_vma addr, struct disassemble_info *info) |
| 106 | { |
| 107 | asymbol **sptr = symbols; |
| 108 | int i; |
| 109 | |
| 110 | printf("%08x", (int)addr); |
| 111 | |
| 112 | for (i = 0; i < symcount; i++) { |
| 113 | asymbol *sym = *sptr++; |
| 114 | |
| 115 | if (addr == sym->value + sym->section->vma) { |
| 116 | printf(" <%s>", sym->name); |
| 117 | break; |
| 118 | } |
| 119 | } |
| 120 | } |
| 121 | |
| 122 | static int insn_printf(void *f, const char *format, ...) |
| 123 | { |
| 124 | va_list args; |
| 125 | size_t n; |
| 126 | |
| 127 | va_start(args, format); |
| 128 | n = vprintf(format, args); |
| 129 | va_end(args); |
| 130 | |
| 131 | return n; |
| 132 | } |
| 133 | |
| 134 | static void host_dasm_init(void) |
| 135 | { |
| 136 | slurp_symtab(g_argv[0]); |
| 137 | |
| 138 | init_disassemble_info(&di, NULL, insn_printf); |
| 139 | di.flavour = bfd_target_unknown_flavour; |
| 140 | di.memory_error_func = dis_asm_memory_error; |
| 141 | di.print_address_func = dis_asm_print_address; |
| 142 | // di.symbol_at_address_func = dis_asm_symbol_at_address; |
| 143 | di.read_memory_func = dis_asm_read_memory; |
| 144 | di.arch = bfd_arch_i386; |
| 145 | di.mach = bfd_mach_i386_i386_intel_syntax; |
| 146 | di.endian = BFD_ENDIAN_LITTLE; |
| 147 | disassemble_init_for_target(&di); |
| 148 | } |
| 149 | |
| 150 | void host_dasm(void *addr, int len) |
| 151 | { |
| 152 | bfd_vma vma_end, vma = (bfd_vma)(int)addr; |
| 153 | static int init_done = 0; |
| 154 | |
| 155 | if (!init_done) { |
| 156 | host_dasm_init(); |
| 157 | init_done = 1; |
| 158 | } |
| 159 | |
| 160 | vma_end = vma + len; |
| 161 | while (vma < vma_end) { |
| 162 | printf(" %p ", (void *)(long)vma); |
| 163 | vma += print_insn_i386_intel(vma, &di); |
| 164 | printf("\n"); |
| 165 | } |
| 166 | } |
| 167 | |