root / dyngen.c @ 4b74fe1f
History | View | Annotate | Download (14.8 kB)
| 1 |
#include <stdlib.h> |
|---|---|
| 2 |
#include <stdio.h> |
| 3 |
#include <stdarg.h> |
| 4 |
#include <inttypes.h> |
| 5 |
#include <elf.h> |
| 6 |
#include <unistd.h> |
| 7 |
#include <fcntl.h> |
| 8 |
|
| 9 |
#include "thunk.h" |
| 10 |
|
| 11 |
/* all dynamically generated functions begin with this code */
|
| 12 |
#define OP_PREFIX "op" |
| 13 |
|
| 14 |
int elf_must_swap(Elf32_Ehdr *h)
|
| 15 |
{
|
| 16 |
union {
|
| 17 |
uint32_t i; |
| 18 |
uint8_t b[4];
|
| 19 |
} swaptest; |
| 20 |
|
| 21 |
swaptest.i = 1;
|
| 22 |
return (h->e_ident[EI_DATA] == ELFDATA2MSB) !=
|
| 23 |
(swaptest.b[0] == 0); |
| 24 |
} |
| 25 |
|
| 26 |
void swab16s(uint16_t *p)
|
| 27 |
{
|
| 28 |
*p = bswap16(*p); |
| 29 |
} |
| 30 |
|
| 31 |
void swab32s(uint32_t *p)
|
| 32 |
{
|
| 33 |
*p = bswap32(*p); |
| 34 |
} |
| 35 |
|
| 36 |
void swab64s(uint32_t *p)
|
| 37 |
{
|
| 38 |
*p = bswap64(*p); |
| 39 |
} |
| 40 |
|
| 41 |
void elf_swap_ehdr(Elf32_Ehdr *h)
|
| 42 |
{
|
| 43 |
swab16s(&h->e_type); /* Object file type */
|
| 44 |
swab16s(&h-> e_machine); /* Architecture */
|
| 45 |
swab32s(&h-> e_version); /* Object file version */
|
| 46 |
swab32s(&h-> e_entry); /* Entry point virtual address */
|
| 47 |
swab32s(&h-> e_phoff); /* Program header table file offset */
|
| 48 |
swab32s(&h-> e_shoff); /* Section header table file offset */
|
| 49 |
swab32s(&h-> e_flags); /* Processor-specific flags */
|
| 50 |
swab16s(&h-> e_ehsize); /* ELF header size in bytes */
|
| 51 |
swab16s(&h-> e_phentsize); /* Program header table entry size */
|
| 52 |
swab16s(&h-> e_phnum); /* Program header table entry count */
|
| 53 |
swab16s(&h-> e_shentsize); /* Section header table entry size */
|
| 54 |
swab16s(&h-> e_shnum); /* Section header table entry count */
|
| 55 |
swab16s(&h-> e_shstrndx); /* Section header string table index */
|
| 56 |
} |
| 57 |
|
| 58 |
void elf_swap_shdr(Elf32_Shdr *h)
|
| 59 |
{
|
| 60 |
swab32s(&h-> sh_name); /* Section name (string tbl index) */
|
| 61 |
swab32s(&h-> sh_type); /* Section type */
|
| 62 |
swab32s(&h-> sh_flags); /* Section flags */
|
| 63 |
swab32s(&h-> sh_addr); /* Section virtual addr at execution */
|
| 64 |
swab32s(&h-> sh_offset); /* Section file offset */
|
| 65 |
swab32s(&h-> sh_size); /* Section size in bytes */
|
| 66 |
swab32s(&h-> sh_link); /* Link to another section */
|
| 67 |
swab32s(&h-> sh_info); /* Additional section information */
|
| 68 |
swab32s(&h-> sh_addralign); /* Section alignment */
|
| 69 |
swab32s(&h-> sh_entsize); /* Entry size if section holds table */
|
| 70 |
} |
| 71 |
|
| 72 |
void elf_swap_phdr(Elf32_Phdr *h)
|
| 73 |
{
|
| 74 |
swab32s(&h->p_type); /* Segment type */
|
| 75 |
swab32s(&h->p_offset); /* Segment file offset */
|
| 76 |
swab32s(&h->p_vaddr); /* Segment virtual address */
|
| 77 |
swab32s(&h->p_paddr); /* Segment physical address */
|
| 78 |
swab32s(&h->p_filesz); /* Segment size in file */
|
| 79 |
swab32s(&h->p_memsz); /* Segment size in memory */
|
| 80 |
swab32s(&h->p_flags); /* Segment flags */
|
| 81 |
swab32s(&h->p_align); /* Segment alignment */
|
| 82 |
} |
| 83 |
|
| 84 |
int do_swap;
|
| 85 |
int e_machine;
|
| 86 |
|
| 87 |
uint16_t get16(uint16_t *p) |
| 88 |
{
|
| 89 |
uint16_t val; |
| 90 |
val = *p; |
| 91 |
if (do_swap)
|
| 92 |
val = bswap16(val); |
| 93 |
return val;
|
| 94 |
} |
| 95 |
|
| 96 |
uint32_t get32(uint32_t *p) |
| 97 |
{
|
| 98 |
uint32_t val; |
| 99 |
val = *p; |
| 100 |
if (do_swap)
|
| 101 |
val = bswap32(val); |
| 102 |
return val;
|
| 103 |
} |
| 104 |
|
| 105 |
void put16(uint16_t *p, uint16_t val)
|
| 106 |
{
|
| 107 |
if (do_swap)
|
| 108 |
val = bswap16(val); |
| 109 |
*p = val; |
| 110 |
} |
| 111 |
|
| 112 |
void put32(uint32_t *p, uint32_t val)
|
| 113 |
{
|
| 114 |
if (do_swap)
|
| 115 |
val = bswap32(val); |
| 116 |
*p = val; |
| 117 |
} |
| 118 |
|
| 119 |
void __attribute__((noreturn)) error(const char *fmt, ...) |
| 120 |
{
|
| 121 |
va_list ap; |
| 122 |
va_start(ap, fmt); |
| 123 |
fprintf(stderr, "dyngen: ");
|
| 124 |
vfprintf(stderr, fmt, ap); |
| 125 |
fprintf(stderr, "\n");
|
| 126 |
va_end(ap); |
| 127 |
exit(1);
|
| 128 |
} |
| 129 |
|
| 130 |
|
| 131 |
Elf32_Shdr *find_elf_section(Elf32_Shdr *shdr, int shnum, const char *shstr, |
| 132 |
const char *name) |
| 133 |
{
|
| 134 |
int i;
|
| 135 |
const char *shname; |
| 136 |
Elf32_Shdr *sec; |
| 137 |
|
| 138 |
for(i = 0; i < shnum; i++) { |
| 139 |
sec = &shdr[i]; |
| 140 |
if (!sec->sh_name)
|
| 141 |
continue;
|
| 142 |
shname = shstr + sec->sh_name; |
| 143 |
if (!strcmp(shname, name))
|
| 144 |
return sec;
|
| 145 |
} |
| 146 |
return NULL; |
| 147 |
} |
| 148 |
|
| 149 |
void *load_data(int fd, long offset, unsigned int size) |
| 150 |
{
|
| 151 |
char *data;
|
| 152 |
|
| 153 |
data = malloc(size); |
| 154 |
if (!data)
|
| 155 |
return NULL; |
| 156 |
lseek(fd, offset, SEEK_SET); |
| 157 |
if (read(fd, data, size) != size) {
|
| 158 |
free(data); |
| 159 |
return NULL; |
| 160 |
} |
| 161 |
return data;
|
| 162 |
} |
| 163 |
|
| 164 |
int strstart(const char *str, const char *val, const char **ptr) |
| 165 |
{
|
| 166 |
const char *p, *q; |
| 167 |
p = str; |
| 168 |
q = val; |
| 169 |
while (*q != '\0') { |
| 170 |
if (*p != *q)
|
| 171 |
return 0; |
| 172 |
p++; |
| 173 |
q++; |
| 174 |
} |
| 175 |
if (ptr)
|
| 176 |
*ptr = p; |
| 177 |
return 1; |
| 178 |
} |
| 179 |
|
| 180 |
#define MAX_ARGS 3 |
| 181 |
|
| 182 |
/* generate op code */
|
| 183 |
void gen_code(const char *name, unsigned long offset, unsigned long size, |
| 184 |
FILE *outfile, uint8_t *text, void *relocs, int nb_relocs, int reloc_sh_type, |
| 185 |
Elf32_Sym *symtab, char *strtab)
|
| 186 |
{
|
| 187 |
int copy_size = 0; |
| 188 |
uint8_t *p_start, *p_end; |
| 189 |
int nb_args, i;
|
| 190 |
uint8_t args_present[MAX_ARGS]; |
| 191 |
const char *sym_name, *p; |
| 192 |
|
| 193 |
/* compute exact size excluding return instruction */
|
| 194 |
p_start = text + offset; |
| 195 |
p_end = p_start + size; |
| 196 |
switch(e_machine) {
|
| 197 |
case EM_386:
|
| 198 |
{
|
| 199 |
uint8_t *p; |
| 200 |
p = p_end - 1;
|
| 201 |
if (p == p_start)
|
| 202 |
error("empty code for %s", name);
|
| 203 |
if (p[0] != 0xc3) |
| 204 |
error("ret expected at the end of %s", name);
|
| 205 |
copy_size = p - p_start; |
| 206 |
} |
| 207 |
break;
|
| 208 |
case EM_PPC:
|
| 209 |
{
|
| 210 |
uint8_t *p; |
| 211 |
p = (void *)(p_end - 4); |
| 212 |
/* find ret */
|
| 213 |
while (p > p_start && get32((uint32_t *)p) != 0x4e800020) |
| 214 |
p -= 4;
|
| 215 |
/* skip double ret */
|
| 216 |
if (p > p_start && get32((uint32_t *)(p - 4)) == 0x4e800020) |
| 217 |
p -= 4;
|
| 218 |
if (p == p_start)
|
| 219 |
error("empty code for %s", name);
|
| 220 |
copy_size = p - p_start; |
| 221 |
} |
| 222 |
break;
|
| 223 |
default:
|
| 224 |
error("unsupported CPU (%d)", e_machine);
|
| 225 |
} |
| 226 |
|
| 227 |
/* compute the number of arguments by looking at the relocations */
|
| 228 |
for(i = 0;i < MAX_ARGS; i++) |
| 229 |
args_present[i] = 0;
|
| 230 |
|
| 231 |
if (reloc_sh_type == SHT_REL) {
|
| 232 |
Elf32_Rel *rel; |
| 233 |
int n;
|
| 234 |
for(i = 0, rel = relocs;i < nb_relocs; i++, rel++) { |
| 235 |
if (rel->r_offset >= offset && rel->r_offset < offset + copy_size) {
|
| 236 |
sym_name = strtab + symtab[ELF32_R_SYM(rel->r_info)].st_name; |
| 237 |
if (strstart(sym_name, "__op_param", &p)) { |
| 238 |
n = strtoul(p, NULL, 10); |
| 239 |
if (n >= MAX_ARGS)
|
| 240 |
error("too many arguments in %s", name);
|
| 241 |
args_present[n - 1] = 1; |
| 242 |
} else {
|
| 243 |
fprintf(outfile, "extern char %s;\n", sym_name);
|
| 244 |
} |
| 245 |
} |
| 246 |
} |
| 247 |
} else {
|
| 248 |
Elf32_Rela *rel; |
| 249 |
int n;
|
| 250 |
for(i = 0, rel = relocs;i < nb_relocs; i++, rel++) { |
| 251 |
if (rel->r_offset >= offset && rel->r_offset < offset + copy_size) {
|
| 252 |
sym_name = strtab + symtab[ELF32_R_SYM(rel->r_info)].st_name; |
| 253 |
if (strstart(sym_name, "__op_param", &p)) { |
| 254 |
n = strtoul(p, NULL, 10); |
| 255 |
if (n >= MAX_ARGS)
|
| 256 |
error("too many arguments in %s", name);
|
| 257 |
args_present[n - 1] = 1; |
| 258 |
} else {
|
| 259 |
fprintf(outfile, "extern char %s;\n", sym_name);
|
| 260 |
} |
| 261 |
} |
| 262 |
} |
| 263 |
} |
| 264 |
|
| 265 |
nb_args = 0;
|
| 266 |
while (nb_args < MAX_ARGS && args_present[nb_args])
|
| 267 |
nb_args++; |
| 268 |
for(i = nb_args; i < MAX_ARGS; i++) {
|
| 269 |
if (args_present[i])
|
| 270 |
error("inconsistent argument numbering in %s", name);
|
| 271 |
} |
| 272 |
|
| 273 |
/* output C code */
|
| 274 |
fprintf(outfile, "extern void %s();\n", name);
|
| 275 |
fprintf(outfile, "static inline void gen_%s(", name);
|
| 276 |
if (nb_args == 0) { |
| 277 |
fprintf(outfile, "void");
|
| 278 |
} else {
|
| 279 |
for(i = 0; i < nb_args; i++) { |
| 280 |
if (i != 0) |
| 281 |
fprintf(outfile, ", ");
|
| 282 |
fprintf(outfile, "long param%d", i + 1); |
| 283 |
} |
| 284 |
} |
| 285 |
fprintf(outfile, ")\n");
|
| 286 |
fprintf(outfile, "{\n");
|
| 287 |
fprintf(outfile, " memcpy(gen_code_ptr, &%s, %d);\n", name, copy_size);
|
| 288 |
|
| 289 |
/* patch relocations */
|
| 290 |
switch(e_machine) {
|
| 291 |
case EM_386:
|
| 292 |
{
|
| 293 |
Elf32_Rel *rel; |
| 294 |
char name[256]; |
| 295 |
int type;
|
| 296 |
long addend;
|
| 297 |
for(i = 0, rel = relocs;i < nb_relocs; i++, rel++) { |
| 298 |
if (rel->r_offset >= offset && rel->r_offset < offset + copy_size) {
|
| 299 |
sym_name = strtab + symtab[ELF32_R_SYM(rel->r_info)].st_name; |
| 300 |
if (strstart(sym_name, "__op_param", &p)) { |
| 301 |
snprintf(name, sizeof(name), "param%s", p); |
| 302 |
} else {
|
| 303 |
snprintf(name, sizeof(name), "(long)(&%s)", sym_name); |
| 304 |
} |
| 305 |
type = ELF32_R_TYPE(rel->r_info); |
| 306 |
addend = get32((uint32_t *)(text + rel->r_offset)); |
| 307 |
switch(type) {
|
| 308 |
case R_386_32:
|
| 309 |
fprintf(outfile, " *(uint32_t *)(gen_code_ptr + %ld) = %s + %ld;\n",
|
| 310 |
rel->r_offset - offset, name, addend); |
| 311 |
break;
|
| 312 |
case R_386_PC32:
|
| 313 |
fprintf(outfile, " *(uint32_t *)(gen_code_ptr + %ld) = %s - (long)(gen_code_ptr + %ld) + %ld;\n",
|
| 314 |
rel->r_offset - offset, name, rel->r_offset - offset, addend); |
| 315 |
break;
|
| 316 |
default:
|
| 317 |
error("unsupported i386 relocation (%d)", type);
|
| 318 |
} |
| 319 |
} |
| 320 |
} |
| 321 |
} |
| 322 |
break;
|
| 323 |
default:
|
| 324 |
error("unsupported CPU for relocations (%d)", e_machine);
|
| 325 |
} |
| 326 |
|
| 327 |
|
| 328 |
fprintf(outfile, " gen_code_ptr += %d;\n", copy_size);
|
| 329 |
fprintf(outfile, "}\n\n");
|
| 330 |
} |
| 331 |
|
| 332 |
/* load an elf object file */
|
| 333 |
int load_elf(const char *filename, FILE *outfile) |
| 334 |
{
|
| 335 |
int fd;
|
| 336 |
Elf32_Ehdr ehdr; |
| 337 |
Elf32_Shdr *sec, *shdr, *symtab_sec, *strtab_sec, *text_sec; |
| 338 |
int i, j, nb_syms;
|
| 339 |
Elf32_Sym *symtab, *sym; |
| 340 |
const char *cpu_name; |
| 341 |
char *shstr, *strtab;
|
| 342 |
uint8_t *text; |
| 343 |
void *relocs;
|
| 344 |
int nb_relocs, reloc_sh_type;
|
| 345 |
|
| 346 |
fd = open(filename, O_RDONLY); |
| 347 |
if (fd < 0) |
| 348 |
error("can't open file '%s'", filename);
|
| 349 |
|
| 350 |
/* Read ELF header. */
|
| 351 |
if (read(fd, &ehdr, sizeof (ehdr)) != sizeof (ehdr)) |
| 352 |
error("unable to read file header");
|
| 353 |
|
| 354 |
/* Check ELF identification. */
|
| 355 |
if (ehdr.e_ident[EI_MAG0] != ELFMAG0
|
| 356 |
|| ehdr.e_ident[EI_MAG1] != ELFMAG1 |
| 357 |
|| ehdr.e_ident[EI_MAG2] != ELFMAG2 |
| 358 |
|| ehdr.e_ident[EI_MAG3] != ELFMAG3 |
| 359 |
|| ehdr.e_ident[EI_CLASS] != ELFCLASS32 |
| 360 |
|| ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
|
| 361 |
error("bad ELF header");
|
| 362 |
} |
| 363 |
|
| 364 |
do_swap = elf_must_swap(&ehdr); |
| 365 |
if (do_swap)
|
| 366 |
elf_swap_ehdr(&ehdr); |
| 367 |
if (ehdr.e_type != ET_REL)
|
| 368 |
error("ELF object file expected");
|
| 369 |
if (ehdr.e_version != EV_CURRENT)
|
| 370 |
error("Invalid ELF version");
|
| 371 |
e_machine = ehdr.e_machine; |
| 372 |
|
| 373 |
/* read section headers */
|
| 374 |
shdr = load_data(fd, ehdr.e_shoff, ehdr.e_shnum * sizeof(Elf32_Shdr));
|
| 375 |
if (do_swap) {
|
| 376 |
for(i = 0; i < ehdr.e_shnum; i++) { |
| 377 |
elf_swap_shdr(&shdr[i]); |
| 378 |
} |
| 379 |
} |
| 380 |
|
| 381 |
sec = &shdr[ehdr.e_shstrndx]; |
| 382 |
shstr = load_data(fd, sec->sh_offset, sec->sh_size); |
| 383 |
|
| 384 |
/* text section */
|
| 385 |
|
| 386 |
text_sec = find_elf_section(shdr, ehdr.e_shnum, shstr, ".text");
|
| 387 |
if (!text_sec)
|
| 388 |
error("could not find .text section");
|
| 389 |
text = load_data(fd, text_sec->sh_offset, text_sec->sh_size); |
| 390 |
|
| 391 |
/* find text relocations, if any */
|
| 392 |
nb_relocs = 0;
|
| 393 |
relocs = NULL;
|
| 394 |
reloc_sh_type = 0;
|
| 395 |
for(i = 0; i < ehdr.e_shnum; i++) { |
| 396 |
sec = &shdr[i]; |
| 397 |
if ((sec->sh_type == SHT_REL || sec->sh_type == SHT_RELA) &&
|
| 398 |
sec->sh_info == (text_sec - shdr)) {
|
| 399 |
reloc_sh_type = sec->sh_type; |
| 400 |
relocs = load_data(fd, sec->sh_offset, sec->sh_size); |
| 401 |
nb_relocs = sec->sh_size / sec->sh_entsize; |
| 402 |
if (do_swap) {
|
| 403 |
if (sec->sh_type == SHT_REL) {
|
| 404 |
Elf32_Rel *rel = relocs; |
| 405 |
for(j = 0, rel = relocs; j < nb_relocs; j++, rel++) { |
| 406 |
swab32s(&rel->r_offset); |
| 407 |
swab32s(&rel->r_info); |
| 408 |
} |
| 409 |
} else {
|
| 410 |
Elf32_Rela *rel = relocs; |
| 411 |
for(j = 0, rel = relocs; j < nb_relocs; j++, rel++) { |
| 412 |
swab32s(&rel->r_offset); |
| 413 |
swab32s(&rel->r_info); |
| 414 |
swab32s(&rel->r_addend); |
| 415 |
} |
| 416 |
} |
| 417 |
} |
| 418 |
break;
|
| 419 |
} |
| 420 |
} |
| 421 |
|
| 422 |
symtab_sec = find_elf_section(shdr, ehdr.e_shnum, shstr, ".symtab");
|
| 423 |
if (!symtab_sec)
|
| 424 |
error("could not find .symtab section");
|
| 425 |
strtab_sec = &shdr[symtab_sec->sh_link]; |
| 426 |
|
| 427 |
symtab = load_data(fd, symtab_sec->sh_offset, symtab_sec->sh_size); |
| 428 |
strtab = load_data(fd, strtab_sec->sh_offset, strtab_sec->sh_size); |
| 429 |
|
| 430 |
nb_syms = symtab_sec->sh_size / sizeof(Elf32_Sym);
|
| 431 |
if (do_swap) {
|
| 432 |
for(i = 0, sym = symtab; i < nb_syms; i++, sym++) { |
| 433 |
swab32s(&sym->st_name); |
| 434 |
swab32s(&sym->st_value); |
| 435 |
swab32s(&sym->st_size); |
| 436 |
swab16s(&sym->st_shndx); |
| 437 |
} |
| 438 |
} |
| 439 |
|
| 440 |
switch(e_machine) {
|
| 441 |
case EM_386:
|
| 442 |
cpu_name = "i386";
|
| 443 |
break;
|
| 444 |
case EM_PPC:
|
| 445 |
cpu_name = "ppc";
|
| 446 |
break;
|
| 447 |
case EM_MIPS:
|
| 448 |
cpu_name = "mips";
|
| 449 |
break;
|
| 450 |
case EM_ARM:
|
| 451 |
cpu_name = "arm";
|
| 452 |
break;
|
| 453 |
case EM_SPARC:
|
| 454 |
cpu_name = "sparc";
|
| 455 |
break;
|
| 456 |
default:
|
| 457 |
error("unsupported CPU (e_machine=%d)", e_machine);
|
| 458 |
} |
| 459 |
|
| 460 |
fprintf(outfile, "#include \"gen-%s.h\"\n\n", cpu_name);
|
| 461 |
|
| 462 |
for(i = 0, sym = symtab; i < nb_syms; i++, sym++) { |
| 463 |
const char *name; |
| 464 |
name = strtab + sym->st_name; |
| 465 |
if (strstart(name, "op_", NULL) || |
| 466 |
strstart(name, "op1_", NULL) || |
| 467 |
strstart(name, "op2_", NULL) || |
| 468 |
strstart(name, "op3_", NULL)) { |
| 469 |
#if 0
|
| 470 |
printf("%4d: %s pos=0x%08x len=%d\n",
|
| 471 |
i, name, sym->st_value, sym->st_size);
|
| 472 |
#endif
|
| 473 |
if (sym->st_shndx != (text_sec - shdr))
|
| 474 |
error("invalid section for opcode (0x%x)", sym->st_shndx);
|
| 475 |
gen_code(name, sym->st_value, sym->st_size, outfile, |
| 476 |
text, relocs, nb_relocs, reloc_sh_type, symtab, strtab); |
| 477 |
} |
| 478 |
} |
| 479 |
|
| 480 |
close(fd); |
| 481 |
return 0; |
| 482 |
} |
| 483 |
|
| 484 |
void usage(void) |
| 485 |
{
|
| 486 |
printf("dyngen (c) 2003 Fabrice Bellard\n"
|
| 487 |
"usage: dyngen [-o outfile] objfile\n"
|
| 488 |
"Generate a dynamic code generator from an object file\n");
|
| 489 |
exit(1);
|
| 490 |
} |
| 491 |
|
| 492 |
int main(int argc, char **argv) |
| 493 |
{
|
| 494 |
int c;
|
| 495 |
const char *filename, *outfilename; |
| 496 |
FILE *outfile; |
| 497 |
|
| 498 |
outfilename = "out.c";
|
| 499 |
for(;;) {
|
| 500 |
c = getopt(argc, argv, "ho:");
|
| 501 |
if (c == -1) |
| 502 |
break;
|
| 503 |
switch(c) {
|
| 504 |
case 'h': |
| 505 |
usage(); |
| 506 |
break;
|
| 507 |
case 'o': |
| 508 |
outfilename = optarg; |
| 509 |
break;
|
| 510 |
} |
| 511 |
} |
| 512 |
if (optind >= argc)
|
| 513 |
usage(); |
| 514 |
filename = argv[optind]; |
| 515 |
outfile = fopen(outfilename, "w");
|
| 516 |
if (!outfile)
|
| 517 |
error("could not open '%s'", outfilename);
|
| 518 |
load_elf(filename, outfile); |
| 519 |
fclose(outfile); |
| 520 |
return 0; |
| 521 |
} |