API tools faq
paste
Advertisement
virushsality

2.6.32 x86_64

virushsality
Dec 12th, 2015
110
0
Never
Add comment
Not a member of Pastebin yet? Sign Up, it unlocks many cool features!
text 16.05 KB | None | 0 0
raw download clone embed print report
  1. #define _GNU_SOURCE
  2. #include <stdio.h>
  3. #include <stdlib.h>
  4. #include <string.h>
  5. #include <ctype.h>
  6.  
  7. #define KSYM_NAME_LEN 127
  8.  
  9.  
  10. struct sym_entry {
  11. unsigned long long addr;
  12. unsigned int len;
  13. unsigned char *sym;
  14. };
  15.  
  16.  
  17. static struct sym_entry *table;
  18. static unsigned int table_size, table_cnt;
  19. static unsigned long long _text, _stext, _etext, _sinittext, _einittext, _sextratext, _eextratext;
  20. static int all_symbols = 0;
  21. static char symbol_prefix_char = '\0';
  22.  
  23. int token_profit[0x10000];
  24.  
  25. /* the table that holds the result of the compression */
  26. unsigned char best_table[256][2];
  27. unsigned char best_table_len[256];
  28.  
  29.  
  30. static void usage(void)
  31. {
  32. fprintf(stderr, "Usage: kallsyms [--all-symbols] [--symbol-prefix=<prefix char>] < in.map > out.S\n");
  33. exit(1);
  34. }
  35.  
  36. /*
  37. * This ignores the intensely annoying "mapping symbols" found
  38. * in ARM ELF files: $a, $t and $d.
  39. */
  40. static inline int is_arm_mapping_symbol(const char *str)
  41. {
  42. return str[0] == '$' && strchr("atd", str[1])
  43. && (str[2] == '\0' || str[2] == '.');
  44. }
  45.  
  46. static int read_symbol(FILE *in, struct sym_entry *s)
  47. {
  48. char str[500];
  49. char *sym, stype;
  50. int rc;
  51.  
  52. rc = fscanf(in, "%llx %c %499s\n", &s->addr, &stype, str);
  53. if (rc != 3) {
  54. if (rc != EOF) {
  55. /* skip line */
  56. fgets(str, 500, in);
  57. }
  58. return -1;
  59. }
  60.  
  61. sym = str;
  62. /* skip prefix char */
  63. if (symbol_prefix_char && str[0] == symbol_prefix_char)
  64. sym++;
  65.  
  66. /* Ignore most absolute/undefined (?) symbols. */
  67. if (strcmp(sym, "_text") == 0)
  68. _text = s->addr;
  69. else if (strcmp(sym, "_stext") == 0)
  70. _stext = s->addr;
  71. else if (strcmp(sym, "_etext") == 0)
  72. _etext = s->addr;
  73. else if (strcmp(sym, "_sinittext") == 0)
  74. _sinittext = s->addr;
  75. else if (strcmp(sym, "_einittext") == 0)
  76. _einittext = s->addr;
  77. else if (strcmp(sym, "_sextratext") == 0)
  78. _sextratext = s->addr;
  79. else if (strcmp(sym, "_eextratext") == 0)
  80. _eextratext = s->addr;
  81. else if (toupper(stype) == 'A')
  82. {
  83. /* Keep these useful absolute symbols */
  84. if (strcmp(sym, "__kernel_syscall_via_break") &&
  85. strcmp(sym, "__kernel_syscall_via_epc") &&
  86. strcmp(sym, "__kernel_sigtramp") &&
  87. strcmp(sym, "__gp"))
  88. return -1;
  89.  
  90. }
  91. else if (toupper(stype) == 'U' ||
  92. is_arm_mapping_symbol(sym))
  93. return -1;
  94. /* exclude also MIPS ELF local symbols ($L123 instead of .L123) */
  95. else if (str[0] == '$')
  96. return -1;
  97.  
  98. /* include the type field in the symbol name, so that it gets
  99. * compressed together */
  100. s->len = strlen(str) + 1;
  101. s->sym = malloc(s->len + 1);
  102. if (!s->sym) {
  103. fprintf(stderr, "kallsyms failure: "
  104. "unable to allocate required amount of memory\n");
  105. exit(EXIT_FAILURE);
  106. }
  107. strcpy((char *)s->sym + 1, str);
  108. s->sym[0] = stype;
  109.  
  110. return 0;
  111. }
  112.  
  113. static int symbol_valid(struct sym_entry *s)
  114. {
  115. /* Symbols which vary between passes. Passes 1 and 2 must have
  116. * identical symbol lists. The kallsyms_* symbols below are only added
  117. * after pass 1, they would be included in pass 2 when --all-symbols is
  118. * specified so exclude them to get a stable symbol list.
  119. */
  120. static char *special_symbols[] = {
  121. "kallsyms_addresses",
  122. "kallsyms_num_syms",
  123. "kallsyms_names",
  124. "kallsyms_markers",
  125. "kallsyms_token_table",
  126. "kallsyms_token_index",
  127.  
  128. /* Exclude linker generated symbols which vary between passes */
  129. "_SDA_BASE_", /* ppc */
  130. "_SDA2_BASE_", /* ppc */
  131. NULL };
  132. int i;
  133. int offset = 1;
  134.  
  135. /* skip prefix char */
  136. if (symbol_prefix_char && *(s->sym + 1) == symbol_prefix_char)
  137. offset++;
  138.  
  139. /* if --all-symbols is not specified, then symbols outside the text
  140. * and inittext sections are discarded */
  141. if (!all_symbols) {
  142. if ((s->addr < _stext || s->addr > _etext)
  143. && (s->addr < _sinittext || s->addr > _einittext)
  144. && (s->addr < _sextratext || s->addr > _eextratext))
  145. return 0;
  146. /* Corner case. Discard any symbols with the same value as
  147. * _etext _einittext or _eextratext; they can move between pass
  148. * 1 and 2 when the kallsyms data are added. If these symbols
  149. * move then they may get dropped in pass 2, which breaks the
  150. * kallsyms rules.
  151. */
  152. if ((s->addr == _etext && strcmp((char*)s->sym + offset, "_etext")) ||
  153. (s->addr == _einittext && strcmp((char*)s->sym + offset, "_einittext")) ||
  154. (s->addr == _eextratext && strcmp((char*)s->sym + offset, "_eextratext")))
  155. return 0;
  156. }
  157.  
  158. /* Exclude symbols which vary between passes. */
  159. if (strstr((char *)s->sym + offset, "_compiled."))
  160. return 0;
  161.  
  162. for (i = 0; special_symbols[i]; i++)
  163. if( strcmp((char *)s->sym + offset, special_symbols[i]) == 0 )
  164. return 0;
  165.  
  166. return 1;
  167. }
  168.  
  169. static void read_map(FILE *in)
  170. {
  171. while (!feof(in)) {
  172. if (table_cnt >= table_size) {
  173. table_size += 10000;
  174. table = realloc(table, sizeof(*table) * table_size);
  175. if (!table) {
  176. fprintf(stderr, "out of memory\n");
  177. exit (1);
  178. }
  179. }
  180. if (read_symbol(in, &table[table_cnt]) == 0)
  181. table_cnt++;
  182. }
  183. }
  184.  
  185. static void output_label(char *label)
  186. {
  187. if (symbol_prefix_char)
  188. printf(".globl %c%s\n", symbol_prefix_char, label);
  189. else
  190. printf(".globl %s\n", label);
  191. printf("\tALGN\n");
  192. if (symbol_prefix_char)
  193. printf("%c%s:\n", symbol_prefix_char, label);
  194. else
  195. printf("%s:\n", label);
  196. }
  197.  
  198. /* uncompress a compressed symbol. When this function is called, the best table
  199. * might still be compressed itself, so the function needs to be recursive */
  200. static int expand_symbol(unsigned char *data, int len, char *result)
  201. {
  202. int c, rlen, total=0;
  203.  
  204. while (len) {
  205. c = *data;
  206. /* if the table holds a single char that is the same as the one
  207. * we are looking for, then end the search */
  208. if (best_table[c][0]==c && best_table_len[c]==1) {
  209. *result++ = c;
  210. total++;
  211. } else {
  212. /* if not, recurse and expand */
  213. rlen = expand_symbol(best_table[c], best_table_len[c], result);
  214. total += rlen;
  215. result += rlen;
  216. }
  217. data++;
  218. len--;
  219. }
  220. *result=0;
  221.  
  222. return total;
  223. }
  224.  
  225. static void write_src(void)
  226. {
  227. unsigned int i, k, off;
  228. unsigned int best_idx[256];
  229. unsigned int *markers;
  230. char buf[KSYM_NAME_LEN+1];
  231.  
  232. printf("#include <asm/types.h>\n");
  233. printf("#if BITS_PER_LONG == 64\n");
  234. printf("#define PTR .quad\n");
  235. printf("#define ALGN .align 8\n");
  236. printf("#else\n");
  237. printf("#define PTR .long\n");
  238. printf("#define ALGN .align 4\n");
  239. printf("#endif\n");
  240.  
  241. printf(".data\n");
  242.  
  243. /* Provide proper symbols relocatability by their '_text'
  244. * relativeness. The symbol names cannot be used to construct
  245. * normal symbol references as the list of symbols contains
  246. * symbols that are declared static and are private to their
  247. * .o files. This prevents .tmp_kallsyms.o or any other
  248. * object from referencing them.
  249. */
  250. output_label("kallsyms_addresses");
  251. for (i = 0; i < table_cnt; i++) {
  252. if (toupper(table[i].sym[0]) != 'A') {
  253. printf("\tPTR\t_text + %#llx\n",
  254. table[i].addr - _text);
  255. } else {
  256. printf("\tPTR\t%#llx\n", table[i].addr);
  257. }
  258. }
  259. printf("\n");
  260.  
  261. output_label("kallsyms_num_syms");
  262. printf("\tPTR\t%d\n", table_cnt);
  263. printf("\n");
  264.  
  265. /* table of offset markers, that give the offset in the compressed stream
  266. * every 256 symbols */
  267. markers = malloc(sizeof(unsigned int) * ((table_cnt + 255) / 256));
  268. if (!markers) {
  269. fprintf(stderr, "kallsyms failure: "
  270. "unable to allocate required memory\n");
  271. exit(EXIT_FAILURE);
  272. }
  273.  
  274. output_label("kallsyms_names");
  275. off = 0;
  276. for (i = 0; i < table_cnt; i++) {
  277. if ((i & 0xFF) == 0)
  278. markers[i >> 8] = off;
  279.  
  280. printf("\t.byte 0x%02x", table[i].len);
  281. for (k = 0; k < table[i].len; k++)
  282. printf(", 0x%02x", table[i].sym[k]);
  283. printf("\n");
  284.  
  285. off += table[i].len + 1;
  286. }
  287. printf("\n");
  288.  
  289. output_label("kallsyms_markers");
  290. for (i = 0; i < ((table_cnt + 255) >> 8); i++)
  291. printf("\tPTR\t%d\n", markers[i]);
  292. printf("\n");
  293.  
  294. free(markers);
  295.  
  296. output_label("kallsyms_token_table");
  297. off = 0;
  298. for (i = 0; i < 256; i++) {
  299. best_idx[i] = off;
  300. expand_symbol(best_table[i], best_table_len[i], buf);
  301. printf("\t.asciz\t\"%s\"\n", buf);
  302. off += strlen(buf) + 1;
  303. }
  304. printf("\n");
  305.  
  306. output_label("kallsyms_token_index");
  307. for (i = 0; i < 256; i++)
  308. printf("\t.short\t%d\n", best_idx[i]);
  309. printf("\n");
  310. }
  311.  
  312.  
  313. /* table lookup compression functions */
  314.  
  315. /* count all the possible tokens in a symbol */
  316. static void learn_symbol(unsigned char *symbol, int len)
  317. {
  318. int i;
  319.  
  320. for (i = 0; i < len - 1; i++)
  321. token_profit[ symbol[i] + (symbol[i + 1] << 8) ]++;
  322. }
  323.  
  324. /* decrease the count for all the possible tokens in a symbol */
  325. static void forget_symbol(unsigned char *symbol, int len)
  326. {
  327. int i;
  328.  
  329. for (i = 0; i < len - 1; i++)
  330. token_profit[ symbol[i] + (symbol[i + 1] << 8) ]--;
  331. }
  332.  
  333. /* remove all the invalid symbols from the table and do the initial token count */
  334. static void build_initial_tok_table(void)
  335. {
  336. unsigned int i, pos;
  337.  
  338. pos = 0;
  339. for (i = 0; i < table_cnt; i++) {
  340. if ( symbol_valid(&table[i]) ) {
  341. if (pos != i)
  342. table[pos] = table[i];
  343. learn_symbol(table[pos].sym, table[pos].len);
  344. pos++;
  345. }
  346. }
  347. table_cnt = pos;
  348. }
  349.  
  350. /* replace a given token in all the valid symbols. Use the sampled symbols
  351. * to update the counts */
  352. static void compress_symbols(unsigned char *str, int idx)
  353. {
  354. unsigned int i, len, size;
  355. unsigned char *p1, *p2;
  356.  
  357. for (i = 0; i < table_cnt; i++) {
  358.  
  359. len = table[i].len;
  360. p1 = table[i].sym;
  361.  
  362. /* find the token on the symbol */
  363. p2 = memmem(p1, len, str, 2);
  364. if (!p2) continue;
  365.  
  366. /* decrease the counts for this symbol's tokens */
  367. forget_symbol(table[i].sym, len);
  368.  
  369. size = len;
  370.  
  371. do {
  372. *p2 = idx;
  373. p2++;
  374. size -= (p2 - p1);
  375. memmove(p2, p2 + 1, size);
  376. p1 = p2;
  377. len--;
  378.  
  379. if (size < 2) break;
  380.  
  381. /* find the token on the symbol */
  382. p2 = memmem(p1, size, str, 2);
  383.  
  384. } while (p2);
  385.  
  386. table[i].len = len;
  387.  
  388. /* increase the counts for this symbol's new tokens */
  389. learn_symbol(table[i].sym, len);
  390. }
  391. }
  392.  
  393. /* search the token with the maximum profit */
  394. static int find_best_token(void)
  395. {
  396. int i, best, bestprofit;
  397.  
  398. bestprofit=-10000;
  399. best = 0;
  400.  
  401. for (i = 0; i < 0x10000; i++) {
  402. if (token_profit[i] > bestprofit) {
  403. best = i;
  404. bestprofit = token_profit[i];
  405. }
  406. }
  407. return best;
  408. }
  409.  
  410. /* this is the core of the algorithm: calculate the "best" table */
  411. static void optimize_result(void)
  412. {
  413. int i, best;
  414.  
  415. /* using the '\0' symbol last allows compress_symbols to use standard
  416. * fast string functions */
  417. for (i = 255; i >= 0; i--) {
  418.  
  419. /* if this table slot is empty (it is not used by an actual
  420. * original char code */
  421. if (!best_table_len[i]) {
  422.  
  423. /* find the token with the breates profit value */
  424. best = find_best_token();
  425.  
  426. /* place it in the "best" table */
  427. best_table_len[i] = 2;
  428. best_table[i][0] = best & 0xFF;
  429. best_table[i][1] = (best >> 8) & 0xFF;
  430.  
  431. /* replace this token in all the valid symbols */
  432. compress_symbols(best_table[i], i);
  433. }
  434. }
  435. }
  436.  
  437. /* start by placing the symbols that are actually used on the table */
  438. static void insert_real_symbols_in_table(void)
  439. {
  440. unsigned int i, j, c;
  441.  
  442. memset(best_table, 0, sizeof(best_table));
  443. memset(best_table_len, 0, sizeof(best_table_len));
  444.  
  445. for (i = 0; i < table_cnt; i++) {
  446. for (j = 0; j < table[i].len; j++) {
  447. c = table[i].sym[j];
  448. best_table[c][0]=c;
  449. best_table_len[c]=1;
  450. }
  451. }
  452. }
  453.  
  454. static void optimize_token_table(void)
  455. {
  456. build_initial_tok_table();
  457.  
  458. insert_real_symbols_in_table();
  459.  
  460. /* When valid symbol is not registered, exit to error */
  461. if (!table_cnt) {
  462. fprintf(stderr, "No valid symbol.\n");
  463. exit(1);
  464. }
  465.  
  466. optimize_result();
  467. }
  468.  
  469.  
  470. int main(int argc, char **argv)
  471. {
  472. if (argc >= 2) {
  473. int i;
  474. for (i = 1; i < argc; i++) {
  475. if(strcmp(argv[i], "--all-symbols") == 0)
  476. all_symbols = 1;
  477. else if (strncmp(argv[i], "--symbol-prefix=", 16) == 0) {
  478. char *p = &argv[i][16];
  479. /* skip quote */
  480. if ((*p == '"' && *(p+2) == '"') || (*p == '\'' && *(p+2) == '\''))
  481. p++;
  482. symbol_prefix_char = *p;
  483. } else
  484. usage();
  485. }
  486. } else if (argc != 1)
  487. usage();
  488.  
  489. read_map(stdin);
  490. optimize_token_table();
  491. write_src();
  492.  
  493. return 0;
  494. }
Advertisement
Add Comment
Please, Sign In to add comment
Advertisement
Public Pastes
Advertisement
We use cookies for various purposes including analytics. By continuing to use Pastebin, you agree to our use of cookies as described in the Cookies Policy.  OK, I Understand
Not a member of Pastebin yet?
Sign Up, it unlocks many cool features!