Masami Hiramatsu | 4ea42b1 | 2009-10-08 17:17:38 -0400 | [diff] [blame] | 1 | /* |
| 2 | * probe-finder.c : C expression to kprobe event converter |
| 3 | * |
| 4 | * Written by Masami Hiramatsu <mhiramat@redhat.com> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; either version 2 of the License, or |
| 9 | * (at your option) any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU General Public License |
| 17 | * along with this program; if not, write to the Free Software |
| 18 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 19 | * |
| 20 | */ |
| 21 | |
| 22 | #include <sys/utsname.h> |
| 23 | #include <sys/types.h> |
| 24 | #include <sys/stat.h> |
| 25 | #include <fcntl.h> |
| 26 | #include <errno.h> |
| 27 | #include <stdio.h> |
| 28 | #include <unistd.h> |
| 29 | #include <getopt.h> |
| 30 | #include <stdlib.h> |
| 31 | #include <string.h> |
| 32 | #include <stdarg.h> |
| 33 | #include <ctype.h> |
| 34 | #include "probe-finder.h" |
| 35 | |
| 36 | |
| 37 | /* Dwarf_Die Linkage to parent Die */ |
| 38 | struct die_link { |
| 39 | struct die_link *parent; /* Parent die */ |
| 40 | Dwarf_Die die; /* Current die */ |
| 41 | }; |
| 42 | |
| 43 | static Dwarf_Debug __dw_debug; |
| 44 | static Dwarf_Error __dw_error; |
| 45 | |
| 46 | static void msg_exit(int ret, const char *fmt, ...) |
| 47 | { |
| 48 | va_list ap; |
| 49 | |
| 50 | va_start(ap, fmt); |
| 51 | fprintf(stderr, "Error: "); |
| 52 | vfprintf(stderr, fmt, ap); |
| 53 | va_end(ap); |
| 54 | |
| 55 | fprintf(stderr, "\n"); |
| 56 | exit(ret); |
| 57 | } |
| 58 | |
| 59 | |
| 60 | /* |
| 61 | * Generic dwarf analysis helpers |
| 62 | */ |
| 63 | |
| 64 | #define X86_32_MAX_REGS 8 |
| 65 | const char *x86_32_regs_table[X86_32_MAX_REGS] = { |
| 66 | "%ax", |
| 67 | "%cx", |
| 68 | "%dx", |
| 69 | "%bx", |
| 70 | "$stack", /* Stack address instead of %sp */ |
| 71 | "%bp", |
| 72 | "%si", |
| 73 | "%di", |
| 74 | }; |
| 75 | |
| 76 | #define X86_64_MAX_REGS 16 |
| 77 | const char *x86_64_regs_table[X86_64_MAX_REGS] = { |
| 78 | "%ax", |
| 79 | "%dx", |
| 80 | "%cx", |
| 81 | "%bx", |
| 82 | "%si", |
| 83 | "%di", |
| 84 | "%bp", |
| 85 | "%sp", |
| 86 | "%r8", |
| 87 | "%r9", |
| 88 | "%r10", |
| 89 | "%r11", |
| 90 | "%r12", |
| 91 | "%r13", |
| 92 | "%r14", |
| 93 | "%r15", |
| 94 | }; |
| 95 | |
| 96 | /* TODO: switching by dwarf address size */ |
| 97 | #ifdef __x86_64__ |
| 98 | #define ARCH_MAX_REGS X86_64_MAX_REGS |
| 99 | #define arch_regs_table x86_64_regs_table |
| 100 | #else |
| 101 | #define ARCH_MAX_REGS X86_32_MAX_REGS |
| 102 | #define arch_regs_table x86_32_regs_table |
| 103 | #endif |
| 104 | |
| 105 | /* Return architecture dependent register string (for kprobe-tracer) */ |
| 106 | static const char *get_arch_regstr(unsigned int n) |
| 107 | { |
| 108 | return (n <= ARCH_MAX_REGS) ? arch_regs_table[n] : NULL; |
| 109 | } |
| 110 | |
| 111 | /* |
| 112 | * Compare the tail of two strings. |
| 113 | * Return 0 if whole of either string is same as another's tail part. |
| 114 | */ |
| 115 | static int strtailcmp(const char *s1, const char *s2) |
| 116 | { |
| 117 | int i1 = strlen(s1); |
| 118 | int i2 = strlen(s2); |
| 119 | while (--i1 > 0 && --i2 > 0) { |
| 120 | if (s1[i1] != s2[i2]) |
| 121 | return s1[i1] - s2[i2]; |
| 122 | } |
| 123 | return 0; |
| 124 | } |
| 125 | |
| 126 | /* Find the fileno of the target file. */ |
| 127 | static Dwarf_Unsigned die_get_fileno(Dwarf_Die cu_die, const char *fname) |
| 128 | { |
| 129 | Dwarf_Signed cnt, i; |
| 130 | Dwarf_Unsigned found = 0; |
| 131 | char **srcs; |
| 132 | int ret; |
| 133 | |
| 134 | if (!fname) |
| 135 | return 0; |
| 136 | |
| 137 | ret = dwarf_srcfiles(cu_die, &srcs, &cnt, &__dw_error); |
| 138 | if (ret == DW_DLV_OK) { |
| 139 | for (i = 0; i < cnt && !found; i++) { |
| 140 | if (strtailcmp(srcs[i], fname) == 0) |
| 141 | found = i + 1; |
| 142 | dwarf_dealloc(__dw_debug, srcs[i], DW_DLA_STRING); |
| 143 | } |
| 144 | for (; i < cnt; i++) |
| 145 | dwarf_dealloc(__dw_debug, srcs[i], DW_DLA_STRING); |
| 146 | dwarf_dealloc(__dw_debug, srcs, DW_DLA_LIST); |
| 147 | } |
| 148 | if (found) |
| 149 | debug("found fno: %d\n", (int)found); |
| 150 | return found; |
| 151 | } |
| 152 | |
| 153 | /* Compare diename and tname */ |
| 154 | static int die_compare_name(Dwarf_Die die, const char *tname) |
| 155 | { |
| 156 | char *name; |
| 157 | int ret; |
| 158 | ret = dwarf_diename(die, &name, &__dw_error); |
| 159 | ERR_IF(ret == DW_DLV_ERROR); |
| 160 | if (ret == DW_DLV_OK) { |
| 161 | ret = strcmp(tname, name); |
| 162 | dwarf_dealloc(__dw_debug, name, DW_DLA_STRING); |
| 163 | } else |
| 164 | ret = -1; |
| 165 | return ret; |
| 166 | } |
| 167 | |
| 168 | /* Check the address is in the subprogram(function). */ |
| 169 | static int die_within_subprogram(Dwarf_Die sp_die, Dwarf_Addr addr, |
| 170 | Dwarf_Signed *offs) |
| 171 | { |
| 172 | Dwarf_Addr lopc, hipc; |
| 173 | int ret; |
| 174 | |
| 175 | /* TODO: check ranges */ |
| 176 | ret = dwarf_lowpc(sp_die, &lopc, &__dw_error); |
| 177 | ERR_IF(ret == DW_DLV_ERROR); |
| 178 | if (ret == DW_DLV_NO_ENTRY) |
| 179 | return 0; |
| 180 | ret = dwarf_highpc(sp_die, &hipc, &__dw_error); |
| 181 | ERR_IF(ret != DW_DLV_OK); |
| 182 | if (lopc <= addr && addr < hipc) { |
| 183 | *offs = addr - lopc; |
| 184 | return 1; |
| 185 | } else |
| 186 | return 0; |
| 187 | } |
| 188 | |
| 189 | /* Check the die is inlined function */ |
| 190 | static Dwarf_Bool die_inlined_subprogram(Dwarf_Die die) |
| 191 | { |
| 192 | /* TODO: check strictly */ |
| 193 | Dwarf_Bool inl; |
| 194 | int ret; |
| 195 | |
| 196 | ret = dwarf_hasattr(die, DW_AT_inline, &inl, &__dw_error); |
| 197 | ERR_IF(ret == DW_DLV_ERROR); |
| 198 | return inl; |
| 199 | } |
| 200 | |
| 201 | /* Get the offset of abstruct_origin */ |
| 202 | static Dwarf_Off die_get_abstract_origin(Dwarf_Die die) |
| 203 | { |
| 204 | Dwarf_Attribute attr; |
| 205 | Dwarf_Off cu_offs; |
| 206 | int ret; |
| 207 | |
| 208 | ret = dwarf_attr(die, DW_AT_abstract_origin, &attr, &__dw_error); |
| 209 | ERR_IF(ret != DW_DLV_OK); |
| 210 | ret = dwarf_formref(attr, &cu_offs, &__dw_error); |
| 211 | ERR_IF(ret != DW_DLV_OK); |
| 212 | dwarf_dealloc(__dw_debug, attr, DW_DLA_ATTR); |
| 213 | return cu_offs; |
| 214 | } |
| 215 | |
| 216 | /* Get entry pc(or low pc, 1st entry of ranges) of the die */ |
| 217 | static Dwarf_Addr die_get_entrypc(Dwarf_Die die) |
| 218 | { |
| 219 | Dwarf_Attribute attr; |
| 220 | Dwarf_Addr addr; |
| 221 | Dwarf_Off offs; |
| 222 | Dwarf_Ranges *ranges; |
| 223 | Dwarf_Signed cnt; |
| 224 | int ret; |
| 225 | |
| 226 | /* Try to get entry pc */ |
| 227 | ret = dwarf_attr(die, DW_AT_entry_pc, &attr, &__dw_error); |
| 228 | ERR_IF(ret == DW_DLV_ERROR); |
| 229 | if (ret == DW_DLV_OK) { |
| 230 | ret = dwarf_formaddr(attr, &addr, &__dw_error); |
| 231 | ERR_IF(ret != DW_DLV_OK); |
| 232 | dwarf_dealloc(__dw_debug, attr, DW_DLA_ATTR); |
| 233 | return addr; |
| 234 | } |
| 235 | |
| 236 | /* Try to get low pc */ |
| 237 | ret = dwarf_lowpc(die, &addr, &__dw_error); |
| 238 | ERR_IF(ret == DW_DLV_ERROR); |
| 239 | if (ret == DW_DLV_OK) |
| 240 | return addr; |
| 241 | |
| 242 | /* Try to get ranges */ |
| 243 | ret = dwarf_attr(die, DW_AT_ranges, &attr, &__dw_error); |
| 244 | ERR_IF(ret != DW_DLV_OK); |
| 245 | ret = dwarf_formref(attr, &offs, &__dw_error); |
| 246 | ERR_IF(ret != DW_DLV_OK); |
| 247 | ret = dwarf_get_ranges(__dw_debug, offs, &ranges, &cnt, NULL, |
| 248 | &__dw_error); |
| 249 | ERR_IF(ret != DW_DLV_OK); |
| 250 | addr = ranges[0].dwr_addr1; |
| 251 | dwarf_ranges_dealloc(__dw_debug, ranges, cnt); |
| 252 | return addr; |
| 253 | } |
| 254 | |
| 255 | /* |
| 256 | * Search a Die from Die tree. |
| 257 | * Note: cur_link->die should be deallocated in this function. |
| 258 | */ |
| 259 | static int __search_die_tree(struct die_link *cur_link, |
| 260 | int (*die_cb)(struct die_link *, void *), |
| 261 | void *data) |
| 262 | { |
| 263 | Dwarf_Die new_die; |
| 264 | struct die_link new_link; |
| 265 | int ret; |
| 266 | |
| 267 | if (!die_cb) |
| 268 | return 0; |
| 269 | |
| 270 | /* Check current die */ |
| 271 | while (!(ret = die_cb(cur_link, data))) { |
| 272 | /* Check child die */ |
| 273 | ret = dwarf_child(cur_link->die, &new_die, &__dw_error); |
| 274 | ERR_IF(ret == DW_DLV_ERROR); |
| 275 | if (ret == DW_DLV_OK) { |
| 276 | new_link.parent = cur_link; |
| 277 | new_link.die = new_die; |
| 278 | ret = __search_die_tree(&new_link, die_cb, data); |
| 279 | if (ret) |
| 280 | break; |
| 281 | } |
| 282 | |
| 283 | /* Move to next sibling */ |
| 284 | ret = dwarf_siblingof(__dw_debug, cur_link->die, &new_die, |
| 285 | &__dw_error); |
| 286 | ERR_IF(ret == DW_DLV_ERROR); |
| 287 | dwarf_dealloc(__dw_debug, cur_link->die, DW_DLA_DIE); |
| 288 | cur_link->die = new_die; |
| 289 | if (ret == DW_DLV_NO_ENTRY) |
| 290 | return 0; |
| 291 | } |
| 292 | dwarf_dealloc(__dw_debug, cur_link->die, DW_DLA_DIE); |
| 293 | return ret; |
| 294 | } |
| 295 | |
| 296 | /* Search a die in its children's die tree */ |
| 297 | static int search_die_from_children(Dwarf_Die parent_die, |
| 298 | int (*die_cb)(struct die_link *, void *), |
| 299 | void *data) |
| 300 | { |
| 301 | struct die_link new_link; |
| 302 | int ret; |
| 303 | |
| 304 | new_link.parent = NULL; |
| 305 | ret = dwarf_child(parent_die, &new_link.die, &__dw_error); |
| 306 | ERR_IF(ret == DW_DLV_ERROR); |
| 307 | if (ret == DW_DLV_OK) |
| 308 | return __search_die_tree(&new_link, die_cb, data); |
| 309 | else |
| 310 | return 0; |
| 311 | } |
| 312 | |
| 313 | /* Find a locdesc corresponding to the address */ |
| 314 | static int attr_get_locdesc(Dwarf_Attribute attr, Dwarf_Locdesc *desc, |
| 315 | Dwarf_Addr addr) |
| 316 | { |
| 317 | Dwarf_Signed lcnt; |
| 318 | Dwarf_Locdesc **llbuf; |
| 319 | int ret, i; |
| 320 | |
| 321 | ret = dwarf_loclist_n(attr, &llbuf, &lcnt, &__dw_error); |
| 322 | ERR_IF(ret != DW_DLV_OK); |
| 323 | ret = DW_DLV_NO_ENTRY; |
| 324 | for (i = 0; i < lcnt; ++i) { |
| 325 | if (llbuf[i]->ld_lopc <= addr && |
| 326 | llbuf[i]->ld_hipc > addr) { |
| 327 | memcpy(desc, llbuf[i], sizeof(Dwarf_Locdesc)); |
| 328 | desc->ld_s = |
| 329 | malloc(sizeof(Dwarf_Loc) * llbuf[i]->ld_cents); |
| 330 | ERR_IF(desc->ld_s == NULL); |
| 331 | memcpy(desc->ld_s, llbuf[i]->ld_s, |
| 332 | sizeof(Dwarf_Loc) * llbuf[i]->ld_cents); |
| 333 | ret = DW_DLV_OK; |
| 334 | break; |
| 335 | } |
| 336 | dwarf_dealloc(__dw_debug, llbuf[i]->ld_s, DW_DLA_LOC_BLOCK); |
| 337 | dwarf_dealloc(__dw_debug, llbuf[i], DW_DLA_LOCDESC); |
| 338 | } |
| 339 | /* Releasing loop */ |
| 340 | for (; i < lcnt; ++i) { |
| 341 | dwarf_dealloc(__dw_debug, llbuf[i]->ld_s, DW_DLA_LOC_BLOCK); |
| 342 | dwarf_dealloc(__dw_debug, llbuf[i], DW_DLA_LOCDESC); |
| 343 | } |
| 344 | dwarf_dealloc(__dw_debug, llbuf, DW_DLA_LIST); |
| 345 | return ret; |
| 346 | } |
| 347 | |
| 348 | /* |
| 349 | * Probe finder related functions |
| 350 | */ |
| 351 | |
| 352 | /* Show a location */ |
| 353 | static void show_location(Dwarf_Loc *loc, struct probe_finder *pf) |
| 354 | { |
| 355 | Dwarf_Small op; |
| 356 | Dwarf_Unsigned regn; |
| 357 | Dwarf_Signed offs; |
| 358 | int deref = 0, ret; |
| 359 | const char *regs; |
| 360 | |
| 361 | op = loc->lr_atom; |
| 362 | |
| 363 | /* If this is based on frame buffer, set the offset */ |
| 364 | if (op == DW_OP_fbreg) { |
| 365 | deref = 1; |
| 366 | offs = (Dwarf_Signed)loc->lr_number; |
| 367 | op = pf->fbloc.ld_s[0].lr_atom; |
| 368 | loc = &pf->fbloc.ld_s[0]; |
| 369 | } else |
| 370 | offs = 0; |
| 371 | |
| 372 | if (op >= DW_OP_breg0 && op <= DW_OP_breg31) { |
| 373 | regn = op - DW_OP_breg0; |
| 374 | offs += (Dwarf_Signed)loc->lr_number; |
| 375 | deref = 1; |
| 376 | } else if (op >= DW_OP_reg0 && op <= DW_OP_reg31) { |
| 377 | regn = op - DW_OP_reg0; |
| 378 | } else if (op == DW_OP_bregx) { |
| 379 | regn = loc->lr_number; |
| 380 | offs += (Dwarf_Signed)loc->lr_number2; |
| 381 | deref = 1; |
| 382 | } else if (op == DW_OP_regx) { |
| 383 | regn = loc->lr_number; |
| 384 | } else |
| 385 | msg_exit(-EINVAL, "Dwarf_OP %d is not supported.\n", op); |
| 386 | |
| 387 | regs = get_arch_regstr(regn); |
| 388 | if (!regs) |
| 389 | msg_exit(-EINVAL, "%lld exceeds max register number.\n", regn); |
| 390 | |
| 391 | if (deref) |
| 392 | ret = snprintf(pf->buf, pf->len, |
| 393 | " %s=%+lld(%s)", pf->var, offs, regs); |
| 394 | else |
| 395 | ret = snprintf(pf->buf, pf->len, " %s=%s", pf->var, regs); |
| 396 | ERR_IF(ret < 0); |
| 397 | ERR_IF(ret >= pf->len); |
| 398 | } |
| 399 | |
| 400 | /* Show a variables in kprobe event format */ |
| 401 | static void show_variable(Dwarf_Die vr_die, struct probe_finder *pf) |
| 402 | { |
| 403 | Dwarf_Attribute attr; |
| 404 | Dwarf_Locdesc ld; |
| 405 | int ret; |
| 406 | |
| 407 | ret = dwarf_attr(vr_die, DW_AT_location, &attr, &__dw_error); |
| 408 | if (ret != DW_DLV_OK) |
| 409 | goto error; |
| 410 | ret = attr_get_locdesc(attr, &ld, (pf->addr - pf->cu_base)); |
| 411 | if (ret != DW_DLV_OK) |
| 412 | goto error; |
| 413 | /* TODO? */ |
| 414 | ERR_IF(ld.ld_cents != 1); |
| 415 | show_location(&ld.ld_s[0], pf); |
| 416 | free(ld.ld_s); |
| 417 | dwarf_dealloc(__dw_debug, attr, DW_DLA_ATTR); |
| 418 | return ; |
| 419 | error: |
| 420 | msg_exit(-1, "Failed to find the location of %s at this address.\n" |
| 421 | " Perhaps, it was optimized out.\n", pf->var); |
| 422 | } |
| 423 | |
| 424 | static int variable_callback(struct die_link *dlink, void *data) |
| 425 | { |
| 426 | struct probe_finder *pf = (struct probe_finder *)data; |
| 427 | Dwarf_Half tag; |
| 428 | int ret; |
| 429 | |
| 430 | ret = dwarf_tag(dlink->die, &tag, &__dw_error); |
| 431 | ERR_IF(ret == DW_DLV_ERROR); |
| 432 | if ((tag == DW_TAG_formal_parameter || |
| 433 | tag == DW_TAG_variable) && |
| 434 | (die_compare_name(dlink->die, pf->var) == 0)) { |
| 435 | show_variable(dlink->die, pf); |
| 436 | return 1; |
| 437 | } |
| 438 | /* TODO: Support struct members and arrays */ |
| 439 | return 0; |
| 440 | } |
| 441 | |
| 442 | /* Find a variable in a subprogram die */ |
| 443 | static void find_variable(Dwarf_Die sp_die, struct probe_finder *pf) |
| 444 | { |
| 445 | int ret; |
| 446 | |
| 447 | if (!is_c_varname(pf->var)) { |
| 448 | /* Output raw parameters */ |
| 449 | ret = snprintf(pf->buf, pf->len, " %s", pf->var); |
| 450 | ERR_IF(ret < 0); |
| 451 | ERR_IF(ret >= pf->len); |
| 452 | return ; |
| 453 | } |
| 454 | |
| 455 | debug("Searching '%s' variable in context.\n", pf->var); |
| 456 | /* Search child die for local variables and parameters. */ |
| 457 | ret = search_die_from_children(sp_die, variable_callback, pf); |
| 458 | if (!ret) |
| 459 | msg_exit(-1, "Failed to find '%s' in this function.\n", |
| 460 | pf->var); |
| 461 | } |
| 462 | |
| 463 | /* Get a frame base on the address */ |
| 464 | static void get_current_frame_base(Dwarf_Die sp_die, struct probe_finder *pf) |
| 465 | { |
| 466 | Dwarf_Attribute attr; |
| 467 | int ret; |
| 468 | |
| 469 | ret = dwarf_attr(sp_die, DW_AT_frame_base, &attr, &__dw_error); |
| 470 | ERR_IF(ret != DW_DLV_OK); |
| 471 | ret = attr_get_locdesc(attr, &pf->fbloc, (pf->addr - pf->cu_base)); |
| 472 | ERR_IF(ret != DW_DLV_OK); |
| 473 | dwarf_dealloc(__dw_debug, attr, DW_DLA_ATTR); |
| 474 | } |
| 475 | |
| 476 | static void free_current_frame_base(struct probe_finder *pf) |
| 477 | { |
| 478 | free(pf->fbloc.ld_s); |
| 479 | memset(&pf->fbloc, 0, sizeof(Dwarf_Locdesc)); |
| 480 | } |
| 481 | |
| 482 | /* Show a probe point to output buffer */ |
| 483 | static void show_probepoint(Dwarf_Die sp_die, Dwarf_Signed offs, |
| 484 | struct probe_finder *pf) |
| 485 | { |
| 486 | struct probe_point *pp = pf->pp; |
| 487 | char *name; |
| 488 | char tmp[MAX_PROBE_BUFFER]; |
| 489 | int ret, i, len; |
| 490 | |
| 491 | /* Output name of probe point */ |
| 492 | ret = dwarf_diename(sp_die, &name, &__dw_error); |
| 493 | ERR_IF(ret == DW_DLV_ERROR); |
| 494 | if (ret == DW_DLV_OK) { |
| 495 | ret = snprintf(tmp, MAX_PROBE_BUFFER, "%s+%u", name, |
| 496 | (unsigned int)offs); |
| 497 | dwarf_dealloc(__dw_debug, name, DW_DLA_STRING); |
| 498 | } else { |
| 499 | /* This function has no name. */ |
| 500 | ret = snprintf(tmp, MAX_PROBE_BUFFER, "0x%llx", pf->addr); |
| 501 | } |
| 502 | ERR_IF(ret < 0); |
| 503 | ERR_IF(ret >= MAX_PROBE_BUFFER); |
| 504 | len = ret; |
| 505 | |
| 506 | /* Find each argument */ |
| 507 | get_current_frame_base(sp_die, pf); |
| 508 | for (i = 0; i < pp->nr_args; i++) { |
| 509 | pf->var = pp->args[i]; |
| 510 | pf->buf = &tmp[len]; |
| 511 | pf->len = MAX_PROBE_BUFFER - len; |
| 512 | find_variable(sp_die, pf); |
| 513 | len += strlen(pf->buf); |
| 514 | } |
| 515 | free_current_frame_base(pf); |
| 516 | |
| 517 | pp->probes[pp->found] = strdup(tmp); |
| 518 | pp->found++; |
| 519 | } |
| 520 | |
| 521 | static int probeaddr_callback(struct die_link *dlink, void *data) |
| 522 | { |
| 523 | struct probe_finder *pf = (struct probe_finder *)data; |
| 524 | Dwarf_Half tag; |
| 525 | Dwarf_Signed offs; |
| 526 | int ret; |
| 527 | |
| 528 | ret = dwarf_tag(dlink->die, &tag, &__dw_error); |
| 529 | ERR_IF(ret == DW_DLV_ERROR); |
| 530 | /* Check the address is in this subprogram */ |
| 531 | if (tag == DW_TAG_subprogram && |
| 532 | die_within_subprogram(dlink->die, pf->addr, &offs)) { |
| 533 | show_probepoint(dlink->die, offs, pf); |
| 534 | return 1; |
| 535 | } |
| 536 | return 0; |
| 537 | } |
| 538 | |
| 539 | /* Find probe point from its line number */ |
| 540 | static void find_by_line(Dwarf_Die cu_die, struct probe_finder *pf) |
| 541 | { |
| 542 | struct probe_point *pp = pf->pp; |
| 543 | Dwarf_Signed cnt, i; |
| 544 | Dwarf_Line *lines; |
| 545 | Dwarf_Unsigned lineno = 0; |
| 546 | Dwarf_Addr addr; |
| 547 | Dwarf_Unsigned fno; |
| 548 | int ret; |
| 549 | |
| 550 | ret = dwarf_srclines(cu_die, &lines, &cnt, &__dw_error); |
| 551 | ERR_IF(ret != DW_DLV_OK); |
| 552 | |
| 553 | for (i = 0; i < cnt; i++) { |
| 554 | ret = dwarf_line_srcfileno(lines[i], &fno, &__dw_error); |
| 555 | ERR_IF(ret != DW_DLV_OK); |
| 556 | if (fno != pf->fno) |
| 557 | continue; |
| 558 | |
| 559 | ret = dwarf_lineno(lines[i], &lineno, &__dw_error); |
| 560 | ERR_IF(ret != DW_DLV_OK); |
| 561 | if (lineno != (Dwarf_Unsigned)pp->line) |
| 562 | continue; |
| 563 | |
| 564 | ret = dwarf_lineaddr(lines[i], &addr, &__dw_error); |
| 565 | ERR_IF(ret != DW_DLV_OK); |
| 566 | debug("Probe point found: 0x%llx\n", addr); |
| 567 | pf->addr = addr; |
| 568 | /* Search a real subprogram including this line, */ |
| 569 | ret = search_die_from_children(cu_die, probeaddr_callback, pf); |
| 570 | if (ret == 0) |
| 571 | msg_exit(-1, |
| 572 | "Probe point is not found in subprograms.\n"); |
| 573 | /* Continuing, because target line might be inlined. */ |
| 574 | } |
| 575 | dwarf_srclines_dealloc(__dw_debug, lines, cnt); |
| 576 | } |
| 577 | |
| 578 | /* Search function from function name */ |
| 579 | static int probefunc_callback(struct die_link *dlink, void *data) |
| 580 | { |
| 581 | struct probe_finder *pf = (struct probe_finder *)data; |
| 582 | struct probe_point *pp = pf->pp; |
| 583 | struct die_link *lk; |
| 584 | Dwarf_Signed offs; |
| 585 | Dwarf_Half tag; |
| 586 | int ret; |
| 587 | |
| 588 | ret = dwarf_tag(dlink->die, &tag, &__dw_error); |
| 589 | ERR_IF(ret == DW_DLV_ERROR); |
| 590 | if (tag == DW_TAG_subprogram) { |
| 591 | if (die_compare_name(dlink->die, pp->function) == 0) { |
| 592 | if (die_inlined_subprogram(dlink->die)) { |
| 593 | /* Inlined function, save it. */ |
| 594 | ret = dwarf_die_CU_offset(dlink->die, |
| 595 | &pf->inl_offs, |
| 596 | &__dw_error); |
| 597 | ERR_IF(ret != DW_DLV_OK); |
| 598 | debug("inline definition offset %lld\n", |
| 599 | pf->inl_offs); |
| 600 | return 0; |
| 601 | } |
| 602 | /* Get probe address */ |
| 603 | pf->addr = die_get_entrypc(dlink->die); |
| 604 | pf->addr += pp->offset; |
| 605 | /* TODO: Check the address in this function */ |
| 606 | show_probepoint(dlink->die, pp->offset, pf); |
| 607 | /* Continue to search */ |
| 608 | } |
| 609 | } else if (tag == DW_TAG_inlined_subroutine && pf->inl_offs) { |
| 610 | if (die_get_abstract_origin(dlink->die) == pf->inl_offs) { |
| 611 | /* Get probe address */ |
| 612 | pf->addr = die_get_entrypc(dlink->die); |
| 613 | pf->addr += pp->offset; |
| 614 | debug("found inline addr: 0x%llx\n", pf->addr); |
| 615 | /* Inlined function. Get a real subprogram */ |
| 616 | for (lk = dlink->parent; lk != NULL; lk = lk->parent) { |
| 617 | tag = 0; |
| 618 | dwarf_tag(lk->die, &tag, &__dw_error); |
| 619 | ERR_IF(ret == DW_DLV_ERROR); |
| 620 | if (tag == DW_TAG_subprogram && |
| 621 | !die_inlined_subprogram(lk->die)) |
| 622 | goto found; |
| 623 | } |
| 624 | msg_exit(-1, "Failed to find real subprogram.\n"); |
| 625 | found: |
| 626 | /* Get offset from subprogram */ |
| 627 | ret = die_within_subprogram(lk->die, pf->addr, &offs); |
| 628 | ERR_IF(!ret); |
| 629 | show_probepoint(lk->die, offs, pf); |
| 630 | /* Continue to search */ |
| 631 | } |
| 632 | } |
| 633 | return 0; |
| 634 | } |
| 635 | |
| 636 | static void find_by_func(Dwarf_Die cu_die, struct probe_finder *pf) |
| 637 | { |
| 638 | search_die_from_children(cu_die, probefunc_callback, pf); |
| 639 | } |
| 640 | |
| 641 | /* Find a probe point */ |
| 642 | int find_probepoint(int fd, struct probe_point *pp) |
| 643 | { |
| 644 | Dwarf_Half addr_size = 0; |
| 645 | Dwarf_Unsigned next_cuh = 0; |
| 646 | Dwarf_Die cu_die = 0; |
| 647 | int cu_number = 0, ret; |
| 648 | struct probe_finder pf = {.pp = pp}; |
| 649 | |
| 650 | ret = dwarf_init(fd, DW_DLC_READ, 0, 0, &__dw_debug, &__dw_error); |
| 651 | if (ret != DW_DLV_OK) |
| 652 | msg_exit(-1, "Failed to call dwarf_init(). " |
| 653 | "Maybe, not a dwarf file?\n"); |
| 654 | |
| 655 | pp->found = 0; |
| 656 | while (++cu_number) { |
| 657 | /* Search CU (Compilation Unit) */ |
| 658 | ret = dwarf_next_cu_header(__dw_debug, NULL, NULL, NULL, |
| 659 | &addr_size, &next_cuh, &__dw_error); |
| 660 | ERR_IF(ret == DW_DLV_ERROR); |
| 661 | if (ret == DW_DLV_NO_ENTRY) |
| 662 | break; |
| 663 | |
| 664 | /* Get the DIE(Debugging Information Entry) of this CU */ |
| 665 | ret = dwarf_siblingof(__dw_debug, 0, &cu_die, &__dw_error); |
| 666 | ERR_IF(ret != DW_DLV_OK); |
| 667 | |
| 668 | /* Check if target file is included. */ |
| 669 | if (pp->file) |
| 670 | pf.fno = die_get_fileno(cu_die, pp->file); |
| 671 | |
| 672 | if (!pp->file || pf.fno) { |
| 673 | /* Save CU base address (for frame_base) */ |
| 674 | ret = dwarf_lowpc(cu_die, &pf.cu_base, &__dw_error); |
| 675 | ERR_IF(ret == DW_DLV_ERROR); |
| 676 | if (ret == DW_DLV_NO_ENTRY) |
| 677 | pf.cu_base = 0; |
| 678 | if (pp->line) |
| 679 | find_by_line(cu_die, &pf); |
| 680 | if (pp->function) |
| 681 | find_by_func(cu_die, &pf); |
| 682 | } |
| 683 | dwarf_dealloc(__dw_debug, cu_die, DW_DLA_DIE); |
| 684 | } |
| 685 | ret = dwarf_finish(__dw_debug, &__dw_error); |
| 686 | ERR_IF(ret != DW_DLV_OK); |
| 687 | |
| 688 | return pp->found; |
| 689 | } |
| 690 | |