tools/perf/util/probe-finder.c

   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 <dwarf-regs.h>
  35
  36 #include "string.h"
  37 #include "event.h"
  38 #include "debug.h"
  39 #include "util.h"
  40 #include "probe-finder.h"
  41
  42 /* Kprobe tracer basic type is up to u64 */
  43 #define MAX_BASIC_TYPE_BITS     64
  44
  45 /*
  46  * Compare the tail of two strings.
  47  * Return 0 if whole of either string is same as another's tail part.
  48  */
  49 static int strtailcmp(const char *s1, const char *s2)
  50 {
  51         int i1 = strlen(s1);
  52         int i2 = strlen(s2);
  53         while (--i1 >= 0 && --i2 >= 0) {
  54                 if (s1[i1] != s2[i2])
  55                         return s1[i1] - s2[i2];
  56         }
  57         return 0;
  58 }
  59
  60 /* Line number list operations */
  61
  62 /* Add a line to line number list */
  63 static int line_list__add_line(struct list_head *head, int line)
  64 {
  65         struct line_node *ln;
  66         struct list_head *p;
  67
  68         /* Reverse search, because new line will be the last one */
  69         list_for_each_entry_reverse(ln, head, list) {
  70                 if (ln->line < line) {
  71                         p = &ln->list;
  72                         goto found;
  73                 } else if (ln->line == line)    /* Already exist */
  74                         return 1;
  75         }
  76         /* List is empty, or the smallest entry */
  77         p = head;
  78 found:
  79         pr_debug("line list: add a line %u\n", line);
  80         ln = zalloc(sizeof(struct line_node));
  81         if (ln == NULL)
  82                 return -ENOMEM;
  83         ln->line = line;
  84         INIT_LIST_HEAD(&ln->list);
  85         list_add(&ln->list, p);
  86         return 0;
  87 }
  88
  89 /* Check if the line in line number list */
  90 static int line_list__has_line(struct list_head *head, int line)
  91 {
  92         struct line_node *ln;
  93
  94         /* Reverse search, because new line will be the last one */
  95         list_for_each_entry(ln, head, list)
  96                 if (ln->line == line)
  97                         return 1;
  98
  99         return 0;
 100 }
 101
 102 /* Init line number list */
 103 static void line_list__init(struct list_head *head)
 104 {
 105         INIT_LIST_HEAD(head);
 106 }
 107
 108 /* Free line number list */
 109 static void line_list__free(struct list_head *head)
 110 {
 111         struct line_node *ln;
 112         while (!list_empty(head)) {
 113                 ln = list_first_entry(head, struct line_node, list);
 114                 list_del(&ln->list);
 115                 free(ln);
 116         }
 117 }
 118
 119 /* Dwarf wrappers */
 120
 121 /* Find the realpath of the target file. */
 122 static const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname)
 123 {
 124         Dwarf_Files *files;
 125         size_t nfiles, i;
 126         const char *src = NULL;
 127         int ret;
 128
 129         if (!fname)
 130                 return NULL;
 131
 132         ret = dwarf_getsrcfiles(cu_die, &files, &nfiles);
 133         if (ret != 0)
 134                 return NULL;
 135
 136         for (i = 0; i < nfiles; i++) {
 137                 src = dwarf_filesrc(files, i, NULL, NULL);
 138                 if (strtailcmp(src, fname) == 0)
 139                         break;
 140         }
 141         if (i == nfiles)
 142                 return NULL;
 143         return src;
 144 }
 145
 146 /* Compare diename and tname */
 147 static bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
 148 {
 149         const char *name;
 150         name = dwarf_diename(dw_die);
 151         return name ? strcmp(tname, name) : -1;
 152 }
 153
 154 /* Get type die, but skip qualifiers and typedef */
 155 static Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
 156 {
 157         Dwarf_Attribute attr;
 158         int tag;
 159
 160         do {
 161                 if (dwarf_attr(vr_die, DW_AT_type, &attr) == NULL ||
 162                     dwarf_formref_die(&attr, die_mem) == NULL)
 163                         return NULL;
 164
 165                 tag = dwarf_tag(die_mem);
 166                 vr_die = die_mem;
 167         } while (tag == DW_TAG_const_type ||
 168                  tag == DW_TAG_restrict_type ||
 169                  tag == DW_TAG_volatile_type ||
 170                  tag == DW_TAG_shared_type ||
 171                  tag == DW_TAG_typedef);
 172
 173         return die_mem;
 174 }
 175
 176 static bool die_is_signed_type(Dwarf_Die *tp_die)
 177 {
 178         Dwarf_Attribute attr;
 179         Dwarf_Word ret;
 180
 181         if (dwarf_attr(tp_die, DW_AT_encoding, &attr) == NULL ||
 182             dwarf_formudata(&attr, &ret) != 0)
 183                 return false;
 184
 185         return (ret == DW_ATE_signed_char || ret == DW_ATE_signed ||
 186                 ret == DW_ATE_signed_fixed);
 187 }
 188
 189 static int die_get_byte_size(Dwarf_Die *tp_die)
 190 {
 191         Dwarf_Attribute attr;
 192         Dwarf_Word ret;
 193
 194         if (dwarf_attr(tp_die, DW_AT_byte_size, &attr) == NULL ||
 195             dwarf_formudata(&attr, &ret) != 0)
 196                 return 0;
 197
 198         return (int)ret;
 199 }
 200
 201 /* Get data_member_location offset */
 202 static int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
 203 {
 204         Dwarf_Attribute attr;
 205         Dwarf_Op *expr;
 206         size_t nexpr;
 207         int ret;
 208
 209         if (dwarf_attr(mb_die, DW_AT_data_member_location, &attr) == NULL)
 210                 return -ENOENT;
 211
 212         if (dwarf_formudata(&attr, offs) != 0) {
 213                 /* DW_AT_data_member_location should be DW_OP_plus_uconst */
 214                 ret = dwarf_getlocation(&attr, &expr, &nexpr);
 215                 if (ret < 0 || nexpr == 0)
 216                         return -ENOENT;
 217
 218                 if (expr[0].atom != DW_OP_plus_uconst || nexpr != 1) {
 219                         pr_debug("Unable to get offset:Unexpected OP %x (%zd)\n",
 220                                  expr[0].atom, nexpr);
 221                         return -ENOTSUP;
 222                 }
 223                 *offs = (Dwarf_Word)expr[0].number;
 224         }
 225         return 0;
 226 }
 227
 228 /* Return values for die_find callbacks */
 229 enum {
 230         DIE_FIND_CB_FOUND = 0,          /* End of Search */
 231         DIE_FIND_CB_CHILD = 1,          /* Search only children */
 232         DIE_FIND_CB_SIBLING = 2,        /* Search only siblings */
 233         DIE_FIND_CB_CONTINUE = 3,       /* Search children and siblings */
 234 };
 235
 236 /* Search a child die */
 237 static Dwarf_Die *die_find_child(Dwarf_Die *rt_die,
 238                                  int (*callback)(Dwarf_Die *, void *),
 239                                  void *data, Dwarf_Die *die_mem)
 240 {
 241         Dwarf_Die child_die;
 242         int ret;
 243
 244         ret = dwarf_child(rt_die, die_mem);
 245         if (ret != 0)
 246                 return NULL;
 247
 248         do {
 249                 ret = callback(die_mem, data);
 250                 if (ret == DIE_FIND_CB_FOUND)
 251                         return die_mem;
 252
 253                 if ((ret & DIE_FIND_CB_CHILD) &&
 254                     die_find_child(die_mem, callback, data, &child_die)) {
 255                         memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
 256                         return die_mem;
 257                 }
 258         } while ((ret & DIE_FIND_CB_SIBLING) &&
 259                  dwarf_siblingof(die_mem, die_mem) == 0);
 260
 261         return NULL;
 262 }
 263
 264 struct __addr_die_search_param {
 265         Dwarf_Addr      addr;
 266         Dwarf_Die       *die_mem;
 267 };
 268
 269 static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
 270 {
 271         struct __addr_die_search_param *ad = data;
 272
 273         if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
 274             dwarf_haspc(fn_die, ad->addr)) {
 275                 memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
 276                 return DWARF_CB_ABORT;
 277         }
 278         return DWARF_CB_OK;
 279 }
 280
 281 /* Search a real subprogram including this line, */
 282 static Dwarf_Die *die_find_real_subprogram(Dwarf_Die *cu_die, Dwarf_Addr addr,
 283                                            Dwarf_Die *die_mem)
 284 {
 285         struct __addr_die_search_param ad;
 286         ad.addr = addr;
 287         ad.die_mem = die_mem;
 288         /* dwarf_getscopes can't find subprogram. */
 289         if (!dwarf_getfuncs(cu_die, __die_search_func_cb, &ad, 0))
 290                 return NULL;
 291         else
 292                 return die_mem;
 293 }
 294
 295 /* die_find callback for inline function search */
 296 static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data)
 297 {
 298         Dwarf_Addr *addr = data;
 299
 300         if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
 301             dwarf_haspc(die_mem, *addr))
 302                 return DIE_FIND_CB_FOUND;
 303
 304         return DIE_FIND_CB_CONTINUE;
 305 }
 306
 307 /* Similar to dwarf_getfuncs, but returns inlined_subroutine if exists. */
 308 static Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
 309                                       Dwarf_Die *die_mem)
 310 {
 311         return die_find_child(sp_die, __die_find_inline_cb, &addr, die_mem);
 312 }
 313
 314 static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
 315 {
 316         const char *name = data;
 317         int tag;
 318
 319         tag = dwarf_tag(die_mem);
 320         if ((tag == DW_TAG_formal_parameter ||
 321              tag == DW_TAG_variable) &&
 322             (die_compare_name(die_mem, name) == 0))
 323                 return DIE_FIND_CB_FOUND;
 324
 325         return DIE_FIND_CB_CONTINUE;
 326 }
 327
 328 /* Find a variable called 'name' */
 329 static Dwarf_Die *die_find_variable(Dwarf_Die *sp_die, const char *name,
 330                                     Dwarf_Die *die_mem)
 331 {
 332         return die_find_child(sp_die, __die_find_variable_cb, (void *)name,
 333                               die_mem);
 334 }
 335
 336 static int __die_find_member_cb(Dwarf_Die *die_mem, void *data)
 337 {
 338         const char *name = data;
 339
 340         if ((dwarf_tag(die_mem) == DW_TAG_member) &&
 341             (die_compare_name(die_mem, name) == 0))
 342                 return DIE_FIND_CB_FOUND;
 343
 344         return DIE_FIND_CB_SIBLING;
 345 }
 346
 347 /* Find a member called 'name' */
 348 static Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
 349                                   Dwarf_Die *die_mem)
 350 {
 351         return die_find_child(st_die, __die_find_member_cb, (void *)name,
 352                               die_mem);
 353 }
 354
 355 /*
 356  * Probe finder related functions
 357  */
 358
 359 /* Show a location */
 360 static int convert_location(Dwarf_Op *op, struct probe_finder *pf)
 361 {
 362         unsigned int regn;
 363         Dwarf_Word offs = 0;
 364         bool ref = false;
 365         const char *regs;
 366         struct kprobe_trace_arg *tvar = pf->tvar;
 367
 368         /* If this is based on frame buffer, set the offset */
 369         if (op->atom == DW_OP_fbreg) {
 370                 if (pf->fb_ops == NULL) {
 371                         pr_warning("The attribute of frame base is not "
 372                                    "supported.\n");
 373                         return -ENOTSUP;
 374                 }
 375                 ref = true;
 376                 offs = op->number;
 377                 op = &pf->fb_ops[0];
 378         }
 379
 380         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
 381                 regn = op->atom - DW_OP_breg0;
 382                 offs += op->number;
 383                 ref = true;
 384         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
 385                 regn = op->atom - DW_OP_reg0;
 386         } else if (op->atom == DW_OP_bregx) {
 387                 regn = op->number;
 388                 offs += op->number2;
 389                 ref = true;
 390         } else if (op->atom == DW_OP_regx) {
 391                 regn = op->number;
 392         } else {
 393                 pr_warning("DW_OP %x is not supported.\n", op->atom);
 394                 return -ENOTSUP;
 395         }
 396
 397         regs = get_arch_regstr(regn);
 398         if (!regs) {
 399                 pr_warning("Mapping for DWARF register number %u missing on this architecture.", regn);
 400                 return -ERANGE;
 401         }
 402
 403         tvar->value = strdup(regs);
 404         if (tvar->value == NULL)
 405                 return -ENOMEM;
 406
 407         if (ref) {
 408                 tvar->ref = zalloc(sizeof(struct kprobe_trace_arg_ref));
 409                 if (tvar->ref == NULL)
 410                         return -ENOMEM;
 411                 tvar->ref->offset = (long)offs;
 412         }
 413         return 0;
 414 }
 415
 416 static int convert_variable_type(Dwarf_Die *vr_die,
 417                                  struct kprobe_trace_arg *targ)
 418 {
 419         Dwarf_Die type;
 420         char buf[16];
 421         int ret;
 422
 423         if (die_get_real_type(vr_die, &type) == NULL) {
 424                 pr_warning("Failed to get a type information of %s.\n",
 425                            dwarf_diename(vr_die));
 426                 return -ENOENT;
 427         }
 428
 429         ret = die_get_byte_size(&type) * 8;
 430         if (ret) {
 431                 /* Check the bitwidth */
 432                 if (ret > MAX_BASIC_TYPE_BITS) {
 433                         pr_info("%s exceeds max-bitwidth."
 434                                 " Cut down to %d bits.\n",
 435                                 dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
 436                         ret = MAX_BASIC_TYPE_BITS;
 437                 }
 438
 439                 ret = snprintf(buf, 16, "%c%d",
 440                                die_is_signed_type(&type) ? 's' : 'u', ret);
 441                 if (ret < 0 || ret >= 16) {
 442                         if (ret >= 16)
 443                                 ret = -E2BIG;
 444                         pr_warning("Failed to convert variable type: %s\n",
 445                                    strerror(-ret));
 446                         return ret;
 447                 }
 448                 targ->type = strdup(buf);
 449                 if (targ->type == NULL)
 450                         return -ENOMEM;
 451         }
 452         return 0;
 453 }
 454
 455 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 456                                     struct perf_probe_arg_field *field,
 457                                     struct kprobe_trace_arg_ref **ref_ptr,
 458                                     Dwarf_Die *die_mem)
 459 {
 460         struct kprobe_trace_arg_ref *ref = *ref_ptr;
 461         Dwarf_Die type;
 462         Dwarf_Word offs;
 463         int ret;
 464
 465         pr_debug("converting %s in %s\n", field->name, varname);
 466         if (die_get_real_type(vr_die, &type) == NULL) {
 467                 pr_warning("Failed to get the type of %s.\n", varname);
 468                 return -ENOENT;
 469         }
 470
 471         /* Check the pointer and dereference */
 472         if (dwarf_tag(&type) == DW_TAG_pointer_type) {
 473                 if (!field->ref) {
 474                         pr_err("Semantic error: %s must be referred by '->'\n",
 475                                field->name);
 476                         return -EINVAL;
 477                 }
 478                 /* Get the type pointed by this pointer */
 479                 if (die_get_real_type(&type, &type) == NULL) {
 480                         pr_warning("Failed to get the type of %s.\n", varname);
 481                         return -ENOENT;
 482                 }
 483                 /* Verify it is a data structure  */
 484                 if (dwarf_tag(&type) != DW_TAG_structure_type) {
 485                         pr_warning("%s is not a data structure.\n", varname);
 486                         return -EINVAL;
 487                 }
 488
 489                 ref = zalloc(sizeof(struct kprobe_trace_arg_ref));
 490                 if (ref == NULL)
 491                         return -ENOMEM;
 492                 if (*ref_ptr)
 493                         (*ref_ptr)->next = ref;
 494                 else
 495                         *ref_ptr = ref;
 496         } else {
 497                 /* Verify it is a data structure  */
 498                 if (dwarf_tag(&type) != DW_TAG_structure_type) {
 499                         pr_warning("%s is not a data structure.\n", varname);
 500                         return -EINVAL;
 501                 }
 502                 if (field->ref) {
 503                         pr_err("Semantic error: %s must be referred by '.'\n",
 504                                field->name);
 505                         return -EINVAL;
 506                 }
 507                 if (!ref) {
 508                         pr_warning("Structure on a register is not "
 509                                    "supported yet.\n");
 510                         return -ENOTSUP;
 511                 }
 512         }
 513
 514         if (die_find_member(&type, field->name, die_mem) == NULL) {
 515                 pr_warning("%s(tyep:%s) has no member %s.\n", varname,
 516                            dwarf_diename(&type), field->name);
 517                 return -EINVAL;
 518         }
 519
 520         /* Get the offset of the field */
 521         ret = die_get_data_member_location(die_mem, &offs);
 522         if (ret < 0) {
 523                 pr_warning("Failed to get the offset of %s.\n", field->name);
 524                 return ret;
 525         }
 526         ref->offset += (long)offs;
 527
 528         /* Converting next field */
 529         if (field->next)
 530                 return convert_variable_fields(die_mem, field->name,
 531                                         field->next, &ref, die_mem);
 532         else
 533                 return 0;
 534 }
 535
 536 /* Show a variables in kprobe event format */
 537 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 538 {
 539         Dwarf_Attribute attr;
 540         Dwarf_Die die_mem;
 541         Dwarf_Op *expr;
 542         size_t nexpr;
 543         int ret;
 544
 545         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
 546                 goto error;
 547         /* TODO: handle more than 1 exprs */
 548         ret = dwarf_getlocation_addr(&attr, pf->addr, &expr, &nexpr, 1);
 549         if (ret <= 0 || nexpr == 0)
 550                 goto error;
 551
 552         ret = convert_location(expr, pf);
 553         if (ret == 0 && pf->pvar->field) {
 554                 ret = convert_variable_fields(vr_die, pf->pvar->var,
 555                                               pf->pvar->field, &pf->tvar->ref,
 556                                               &die_mem);
 557                 vr_die = &die_mem;
 558         }
 559         if (ret == 0) {
 560                 if (pf->pvar->type) {
 561                         pf->tvar->type = strdup(pf->pvar->type);
 562                         if (pf->tvar->type == NULL)
 563                                 ret = -ENOMEM;
 564                 } else
 565                         ret = convert_variable_type(vr_die, pf->tvar);
 566         }
 567         /* *expr will be cached in libdw. Don't free it. */
 568         return ret;
 569 error:
 570         /* TODO: Support const_value */
 571         pr_err("Failed to find the location of %s at this address.\n"
 572                " Perhaps, it has been optimized out.\n", pf->pvar->var);
 573         return -ENOENT;
 574 }
 575
 576 /* Find a variable in a subprogram die */
 577 static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
 578 {
 579         Dwarf_Die vr_die;
 580         char buf[32], *ptr;
 581         int ret;
 582
 583         /* TODO: Support arrays */
 584         if (pf->pvar->name)
 585                 pf->tvar->name = strdup(pf->pvar->name);
 586         else {
 587                 ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
 588                 if (ret < 0)
 589                         return ret;
 590                 ptr = strchr(buf, ':'); /* Change type separator to _ */
 591                 if (ptr)
 592                         *ptr = '_';
 593                 pf->tvar->name = strdup(buf);
 594         }
 595         if (pf->tvar->name == NULL)
 596                 return -ENOMEM;
 597
 598         if (!is_c_varname(pf->pvar->var)) {
 599                 /* Copy raw parameters */
 600                 pf->tvar->value = strdup(pf->pvar->var);
 601                 if (pf->tvar->value == NULL)
 602                         return -ENOMEM;
 603                 else
 604                         return 0;
 605         }
 606
 607         pr_debug("Searching '%s' variable in context.\n",
 608                  pf->pvar->var);
 609         /* Search child die for local variables and parameters. */
 610         if (!die_find_variable(sp_die, pf->pvar->var, &vr_die)) {
 611                 pr_warning("Failed to find '%s' in this function.\n",
 612                            pf->pvar->var);
 613                 return -ENOENT;
 614         }
 615         return convert_variable(&vr_die, pf);
 616 }
 617
 618 /* Show a probe point to output buffer */
 619 static int convert_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
 620 {
 621         struct kprobe_trace_event *tev;
 622         Dwarf_Addr eaddr;
 623         Dwarf_Die die_mem;
 624         const char *name;
 625         int ret, i;
 626         Dwarf_Attribute fb_attr;
 627         size_t nops;
 628
 629         if (pf->ntevs == pf->max_tevs) {
 630                 pr_warning("Too many( > %d) probe point found.\n",
 631                            pf->max_tevs);
 632                 return -ERANGE;
 633         }
 634         tev = &pf->tevs[pf->ntevs++];
 635
 636         /* If no real subprogram, find a real one */
 637         if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) {
 638                 sp_die = die_find_real_subprogram(&pf->cu_die,
 639                                                  pf->addr, &die_mem);
 640                 if (!sp_die) {
 641                         pr_warning("Failed to find probe point in any "
 642                                    "functions.\n");
 643                         return -ENOENT;
 644                 }
 645         }
 646
 647         /* Copy the name of probe point */
 648         name = dwarf_diename(sp_die);
 649         if (name) {
 650                 if (dwarf_entrypc(sp_die, &eaddr) != 0) {
 651                         pr_warning("Failed to get entry pc of %s\n",
 652                                    dwarf_diename(sp_die));
 653                         return -ENOENT;
 654                 }
 655                 tev->point.symbol = strdup(name);
 656                 if (tev->point.symbol == NULL)
 657                         return -ENOMEM;
 658                 tev->point.offset = (unsigned long)(pf->addr - eaddr);
 659         } else
 660                 /* This function has no name. */
 661                 tev->point.offset = (unsigned long)pf->addr;
 662
 663         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
 664                  tev->point.offset);
 665
 666         /* Get the frame base attribute/ops */
 667         dwarf_attr(sp_die, DW_AT_frame_base, &fb_attr);
 668         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 669         if (ret <= 0 || nops == 0) {
 670                 pf->fb_ops = NULL;
 671         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
 672                    pf->cfi != NULL) {
 673                 Dwarf_Frame *frame;
 674                 if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
 675                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
 676                         pr_warning("Failed to get CFA on 0x%jx\n",
 677                                    (uintmax_t)pf->addr);
 678                         return -ENOENT;
 679                 }
 680         }
 681
 682         /* Find each argument */
 683         tev->nargs = pf->pev->nargs;
 684         tev->args = zalloc(sizeof(struct kprobe_trace_arg) * tev->nargs);
 685         if (tev->args == NULL)
 686                 return -ENOMEM;
 687         for (i = 0; i < pf->pev->nargs; i++) {
 688                 pf->pvar = &pf->pev->args[i];
 689                 pf->tvar = &tev->args[i];
 690                 ret = find_variable(sp_die, pf);
 691                 if (ret != 0)
 692                         return ret;
 693         }
 694
 695         /* *pf->fb_ops will be cached in libdw. Don't free it. */
 696         pf->fb_ops = NULL;
 697         return 0;
 698 }
 699
 700 /* Find probe point from its line number */
 701 static int find_probe_point_by_line(struct probe_finder *pf)
 702 {
 703         Dwarf_Lines *lines;
 704         Dwarf_Line *line;
 705         size_t nlines, i;
 706         Dwarf_Addr addr;
 707         int lineno;
 708         int ret = 0;
 709
 710         if (dwarf_getsrclines(&pf->cu_die, &lines, &nlines) != 0) {
 711                 pr_warning("No source lines found in this CU.\n");
 712                 return -ENOENT;
 713         }
 714
 715         for (i = 0; i < nlines && ret == 0; i++) {
 716                 line = dwarf_onesrcline(lines, i);
 717                 if (dwarf_lineno(line, &lineno) != 0 ||
 718                     lineno != pf->lno)
 719                         continue;
 720
 721                 /* TODO: Get fileno from line, but how? */
 722                 if (strtailcmp(dwarf_linesrc(line, NULL, NULL), pf->fname) != 0)
 723                         continue;
 724
 725                 if (dwarf_lineaddr(line, &addr) != 0) {
 726                         pr_warning("Failed to get the address of the line.\n");
 727                         return -ENOENT;
 728                 }
 729                 pr_debug("Probe line found: line[%d]:%d addr:0x%jx\n",
 730                          (int)i, lineno, (uintmax_t)addr);
 731                 pf->addr = addr;
 732
 733                 ret = convert_probe_point(NULL, pf);
 734                 /* Continuing, because target line might be inlined. */
 735         }
 736         return ret;
 737 }
 738
 739 /* Find lines which match lazy pattern */
 740 static int find_lazy_match_lines(struct list_head *head,
 741                                  const char *fname, const char *pat)
 742 {
 743         char *fbuf, *p1, *p2;
 744         int fd, ret, line, nlines = 0;
 745         struct stat st;
 746
 747         fd = open(fname, O_RDONLY);
 748         if (fd < 0) {
 749                 pr_warning("Failed to open %s: %s\n", fname, strerror(-fd));
 750                 return fd;
 751         }
 752
 753         ret = fstat(fd, &st);
 754         if (ret < 0) {
 755                 pr_warning("Failed to get the size of %s: %s\n",
 756                            fname, strerror(errno));
 757                 return ret;
 758         }
 759         fbuf = xmalloc(st.st_size + 2);
 760         ret = read(fd, fbuf, st.st_size);
 761         if (ret < 0) {
 762                 pr_warning("Failed to read %s: %s\n", fname, strerror(errno));
 763                 return ret;
 764         }
 765         close(fd);
 766         fbuf[st.st_size] = '\n';        /* Dummy line */
 767         fbuf[st.st_size + 1] = '\0';
 768         p1 = fbuf;
 769         line = 1;
 770         while ((p2 = strchr(p1, '\n')) != NULL) {
 771                 *p2 = '\0';
 772                 if (strlazymatch(p1, pat)) {
 773                         line_list__add_line(head, line);
 774                         nlines++;
 775                 }
 776                 line++;
 777                 p1 = p2 + 1;
 778         }
 779         free(fbuf);
 780         return nlines;
 781 }
 782
 783 /* Find probe points from lazy pattern  */
 784 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 785 {
 786         Dwarf_Lines *lines;
 787         Dwarf_Line *line;
 788         size_t nlines, i;
 789         Dwarf_Addr addr;
 790         Dwarf_Die die_mem;
 791         int lineno;
 792         int ret = 0;
 793
 794         if (list_empty(&pf->lcache)) {
 795                 /* Matching lazy line pattern */
 796                 ret = find_lazy_match_lines(&pf->lcache, pf->fname,
 797                                             pf->pev->point.lazy_line);
 798                 if (ret == 0) {
 799                         pr_debug("No matched lines found in %s.\n", pf->fname);
 800                         return 0;
 801                 } else if (ret < 0)
 802                         return ret;
 803         }
 804
 805         if (dwarf_getsrclines(&pf->cu_die, &lines, &nlines) != 0) {
 806                 pr_warning("No source lines found in this CU.\n");
 807                 return -ENOENT;
 808         }
 809
 810         for (i = 0; i < nlines && ret >= 0; i++) {
 811                 line = dwarf_onesrcline(lines, i);
 812
 813                 if (dwarf_lineno(line, &lineno) != 0 ||
 814                     !line_list__has_line(&pf->lcache, lineno))
 815                         continue;
 816
 817                 /* TODO: Get fileno from line, but how? */
 818                 if (strtailcmp(dwarf_linesrc(line, NULL, NULL), pf->fname) != 0)
 819                         continue;
 820
 821                 if (dwarf_lineaddr(line, &addr) != 0) {
 822                         pr_debug("Failed to get the address of line %d.\n",
 823                                  lineno);
 824                         continue;
 825                 }
 826                 if (sp_die) {
 827                         /* Address filtering 1: does sp_die include addr? */
 828                         if (!dwarf_haspc(sp_die, addr))
 829                                 continue;
 830                         /* Address filtering 2: No child include addr? */
 831                         if (die_find_inlinefunc(sp_die, addr, &die_mem))
 832                                 continue;
 833                 }
 834
 835                 pr_debug("Probe line found: line[%d]:%d addr:0x%llx\n",
 836                          (int)i, lineno, (unsigned long long)addr);
 837                 pf->addr = addr;
 838
 839                 ret = convert_probe_point(sp_die, pf);
 840                 /* Continuing, because target line might be inlined. */
 841         }
 842         /* TODO: deallocate lines, but how? */
 843         return ret;
 844 }
 845
 846 /* Callback parameter with return value */
 847 struct dwarf_callback_param {
 848         void *data;
 849         int retval;
 850 };
 851
 852 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 853 {
 854         struct dwarf_callback_param *param = data;
 855         struct probe_finder *pf = param->data;
 856         struct perf_probe_point *pp = &pf->pev->point;
 857         Dwarf_Addr addr;
 858
 859         if (pp->lazy_line)
 860                 param->retval = find_probe_point_lazy(in_die, pf);
 861         else {
 862                 /* Get probe address */
 863                 if (dwarf_entrypc(in_die, &addr) != 0) {
 864                         pr_warning("Failed to get entry pc of %s.\n",
 865                                    dwarf_diename(in_die));
 866                         param->retval = -ENOENT;
 867                         return DWARF_CB_ABORT;
 868                 }
 869                 pf->addr = addr;
 870                 pf->addr += pp->offset;
 871                 pr_debug("found inline addr: 0x%jx\n",
 872                          (uintmax_t)pf->addr);
 873
 874                 param->retval = convert_probe_point(in_die, pf);
 875                 if (param->retval < 0)
 876                         return DWARF_CB_ABORT;
 877         }
 878
 879         return DWARF_CB_OK;
 880 }
 881
 882 /* Search function from function name */
 883 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
 884 {
 885         struct dwarf_callback_param *param = data;
 886         struct probe_finder *pf = param->data;
 887         struct perf_probe_point *pp = &pf->pev->point;
 888
 889         /* Check tag and diename */
 890         if (dwarf_tag(sp_die) != DW_TAG_subprogram ||
 891             die_compare_name(sp_die, pp->function) != 0)
 892                 return DWARF_CB_OK;
 893
 894         pf->fname = dwarf_decl_file(sp_die);
 895         if (pp->line) { /* Function relative line */
 896                 dwarf_decl_line(sp_die, &pf->lno);
 897                 pf->lno += pp->line;
 898                 param->retval = find_probe_point_by_line(pf);
 899         } else if (!dwarf_func_inline(sp_die)) {
 900                 /* Real function */
 901                 if (pp->lazy_line)
 902                         param->retval = find_probe_point_lazy(sp_die, pf);
 903                 else {
 904                         if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
 905                                 pr_warning("Failed to get entry pc of %s.\n",
 906                                            dwarf_diename(sp_die));
 907                                 param->retval = -ENOENT;
 908                                 return DWARF_CB_ABORT;
 909                         }
 910                         pf->addr += pp->offset;
 911                         /* TODO: Check the address in this function */
 912                         param->retval = convert_probe_point(sp_die, pf);
 913                 }
 914         } else {
 915                 struct dwarf_callback_param _param = {.data = (void *)pf,
 916                                                       .retval = 0};
 917                 /* Inlined function: search instances */
 918                 dwarf_func_inline_instances(sp_die, probe_point_inline_cb,
 919                                             &_param);
 920                 param->retval = _param.retval;
 921         }
 922
 923         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
 924 }
 925
 926 static int find_probe_point_by_func(struct probe_finder *pf)
 927 {
 928         struct dwarf_callback_param _param = {.data = (void *)pf,
 929                                               .retval = 0};
 930         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
 931         return _param.retval;
 932 }
 933
 934 /* Find kprobe_trace_events specified by perf_probe_event from debuginfo */
 935 int find_kprobe_trace_events(int fd, struct perf_probe_event *pev,
 936                              struct kprobe_trace_event **tevs, int max_tevs)
 937 {
 938         struct probe_finder pf = {.pev = pev, .max_tevs = max_tevs};
 939         struct perf_probe_point *pp = &pev->point;
 940         Dwarf_Off off, noff;
 941         size_t cuhl;
 942         Dwarf_Die *diep;
 943         Dwarf *dbg;
 944         int ret = 0;
 945
 946         pf.tevs = zalloc(sizeof(struct kprobe_trace_event) * max_tevs);
 947         if (pf.tevs == NULL)
 948                 return -ENOMEM;
 949         *tevs = pf.tevs;
 950         pf.ntevs = 0;
 951
 952         dbg = dwarf_begin(fd, DWARF_C_READ);
 953         if (!dbg) {
 954                 pr_warning("No dwarf info found in the vmlinux - "
 955                         "please rebuild with CONFIG_DEBUG_INFO=y.\n");
 956                 return -EBADF;
 957         }
 958
 959         /* Get the call frame information from this dwarf */
 960         pf.cfi = dwarf_getcfi(dbg);
 961
 962         off = 0;
 963         line_list__init(&pf.lcache);
 964         /* Loop on CUs (Compilation Unit) */
 965         while (!dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) &&
 966                ret >= 0) {
 967                 /* Get the DIE(Debugging Information Entry) of this CU */
 968                 diep = dwarf_offdie(dbg, off + cuhl, &pf.cu_die);
 969                 if (!diep)
 970                         continue;
 971
 972                 /* Check if target file is included. */
 973                 if (pp->file)
 974                         pf.fname = cu_find_realpath(&pf.cu_die, pp->file);
 975                 else
 976                         pf.fname = NULL;
 977
 978                 if (!pp->file || pf.fname) {
 979                         if (pp->function)
 980                                 ret = find_probe_point_by_func(&pf);
 981                         else if (pp->lazy_line)
 982                                 ret = find_probe_point_lazy(NULL, &pf);
 983                         else {
 984                                 pf.lno = pp->line;
 985                                 ret = find_probe_point_by_line(&pf);
 986                         }
 987                 }
 988                 off = noff;
 989         }
 990         line_list__free(&pf.lcache);
 991         dwarf_end(dbg);
 992
 993         return (ret < 0) ? ret : pf.ntevs;
 994 }
 995
 996 /* Reverse search */
 997 int find_perf_probe_point(int fd, unsigned long addr,
 998                           struct perf_probe_point *ppt)
 999 {
1000         Dwarf_Die cudie, spdie, indie;
1001         Dwarf *dbg;
1002         Dwarf_Line *line;
1003         Dwarf_Addr laddr, eaddr;
1004         const char *tmp;
1005         int lineno, ret = 0;
1006         bool found = false;
1007
1008         dbg = dwarf_begin(fd, DWARF_C_READ);
1009         if (!dbg)
1010                 return -EBADF;
1011
1012         /* Find cu die */
1013         if (!dwarf_addrdie(dbg, (Dwarf_Addr)addr, &cudie)) {
1014                 ret = -EINVAL;
1015                 goto end;
1016         }
1017
1018         /* Find a corresponding line */
1019         line = dwarf_getsrc_die(&cudie, (Dwarf_Addr)addr);
1020         if (line) {
1021                 if (dwarf_lineaddr(line, &laddr) == 0 &&
1022                     (Dwarf_Addr)addr == laddr &&
1023                     dwarf_lineno(line, &lineno) == 0) {
1024                         tmp = dwarf_linesrc(line, NULL, NULL);
1025                         if (tmp) {
1026                                 ppt->line = lineno;
1027                                 ppt->file = strdup(tmp);
1028                                 if (ppt->file == NULL) {
1029                                         ret = -ENOMEM;
1030                                         goto end;
1031                                 }
1032                                 found = true;
1033                         }
1034                 }
1035         }
1036
1037         /* Find a corresponding function */
1038         if (die_find_real_subprogram(&cudie, (Dwarf_Addr)addr, &spdie)) {
1039                 tmp = dwarf_diename(&spdie);
1040                 if (!tmp || dwarf_entrypc(&spdie, &eaddr) != 0)
1041                         goto end;
1042
1043                 if (ppt->line) {
1044                         if (die_find_inlinefunc(&spdie, (Dwarf_Addr)addr,
1045                                                 &indie)) {
1046                                 /* addr in an inline function */
1047                                 tmp = dwarf_diename(&indie);
1048                                 if (!tmp)
1049                                         goto end;
1050                                 ret = dwarf_decl_line(&indie, &lineno);
1051                         } else {
1052                                 if (eaddr == addr) {    /* Function entry */
1053                                         lineno = ppt->line;
1054                                         ret = 0;
1055                                 } else
1056                                         ret = dwarf_decl_line(&spdie, &lineno);
1057                         }
1058                         if (ret == 0) {
1059                                 /* Make a relative line number */
1060                                 ppt->line -= lineno;
1061                                 goto found;
1062                         }
1063                 }
1064                 /* We don't have a line number, let's use offset */
1065                 ppt->offset = addr - (unsigned long)eaddr;
1066 found:
1067                 ppt->function = strdup(tmp);
1068                 if (ppt->function == NULL) {
1069                         ret = -ENOMEM;
1070                         goto end;
1071                 }
1072                 found = true;
1073         }
1074
1075 end:
1076         dwarf_end(dbg);
1077         if (ret >= 0)
1078                 ret = found ? 1 : 0;
1079         return ret;
1080 }
1081
1082 /* Add a line and store the src path */
1083 static int line_range_add_line(const char *src, unsigned int lineno,
1084                                struct line_range *lr)
1085 {
1086         /* Copy real path */
1087         if (!lr->path) {
1088                 lr->path = strdup(src);
1089                 if (lr->path == NULL)
1090                         return -ENOMEM;
1091         }
1092         return line_list__add_line(&lr->line_list, lineno);
1093 }
1094
1095 /* Search function declaration lines */
1096 static int line_range_funcdecl_cb(Dwarf_Die *sp_die, void *data)
1097 {
1098         struct dwarf_callback_param *param = data;
1099         struct line_finder *lf = param->data;
1100         const char *src;
1101         int lineno;
1102
1103         src = dwarf_decl_file(sp_die);
1104         if (src && strtailcmp(src, lf->fname) != 0)
1105                 return DWARF_CB_OK;
1106
1107         if (dwarf_decl_line(sp_die, &lineno) != 0 ||
1108             (lf->lno_s > lineno || lf->lno_e < lineno))
1109                 return DWARF_CB_OK;
1110
1111         param->retval = line_range_add_line(src, lineno, lf->lr);
1112         if (param->retval < 0)
1113                 return DWARF_CB_ABORT;
1114         return DWARF_CB_OK;
1115 }
1116
1117 static int find_line_range_func_decl_lines(struct line_finder *lf)
1118 {
1119         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1120         dwarf_getfuncs(&lf->cu_die, line_range_funcdecl_cb, &param, 0);
1121         return param.retval;
1122 }
1123
1124 /* Find line range from its line number */
1125 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1126 {
1127         Dwarf_Lines *lines;
1128         Dwarf_Line *line;
1129         size_t nlines, i;
1130         Dwarf_Addr addr;
1131         int lineno, ret = 0;
1132         const char *src;
1133         Dwarf_Die die_mem;
1134
1135         line_list__init(&lf->lr->line_list);
1136         if (dwarf_getsrclines(&lf->cu_die, &lines, &nlines) != 0) {
1137                 pr_warning("No source lines found in this CU.\n");
1138                 return -ENOENT;
1139         }
1140
1141         /* Search probable lines on lines list */
1142         for (i = 0; i < nlines; i++) {
1143                 line = dwarf_onesrcline(lines, i);
1144                 if (dwarf_lineno(line, &lineno) != 0 ||
1145                     (lf->lno_s > lineno || lf->lno_e < lineno))
1146                         continue;
1147
1148                 if (sp_die) {
1149                         /* Address filtering 1: does sp_die include addr? */
1150                         if (dwarf_lineaddr(line, &addr) != 0 ||
1151                             !dwarf_haspc(sp_die, addr))
1152                                 continue;
1153
1154                         /* Address filtering 2: No child include addr? */
1155                         if (die_find_inlinefunc(sp_die, addr, &die_mem))
1156                                 continue;
1157                 }
1158
1159                 /* TODO: Get fileno from line, but how? */
1160                 src = dwarf_linesrc(line, NULL, NULL);
1161                 if (strtailcmp(src, lf->fname) != 0)
1162                         continue;
1163
1164                 ret = line_range_add_line(src, lineno, lf->lr);
1165                 if (ret < 0)
1166                         return ret;
1167         }
1168
1169         /*
1170          * Dwarf lines doesn't include function declarations. We have to
1171          * check functions list or given function.
1172          */
1173         if (sp_die) {
1174                 src = dwarf_decl_file(sp_die);
1175                 if (src && dwarf_decl_line(sp_die, &lineno) == 0 &&
1176                     (lf->lno_s <= lineno && lf->lno_e >= lineno))
1177                         ret = line_range_add_line(src, lineno, lf->lr);
1178         } else
1179                 ret = find_line_range_func_decl_lines(lf);
1180
1181         /* Update status */
1182         if (ret >= 0)
1183                 if (!list_empty(&lf->lr->line_list))
1184                         ret = lf->found = 1;
1185                 else
1186                         ret = 0;        /* Lines are not found */
1187         else {
1188                 free(lf->lr->path);
1189                 lf->lr->path = NULL;
1190         }
1191         return ret;
1192 }
1193
1194 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1195 {
1196         struct dwarf_callback_param *param = data;
1197
1198         param->retval = find_line_range_by_line(in_die, param->data);
1199         return DWARF_CB_ABORT;  /* No need to find other instances */
1200 }
1201
1202 /* Search function from function name */
1203 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1204 {
1205         struct dwarf_callback_param *param = data;
1206         struct line_finder *lf = param->data;
1207         struct line_range *lr = lf->lr;
1208
1209         if (dwarf_tag(sp_die) == DW_TAG_subprogram &&
1210             die_compare_name(sp_die, lr->function) == 0) {
1211                 lf->fname = dwarf_decl_file(sp_die);
1212                 dwarf_decl_line(sp_die, &lr->offset);
1213                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1214                 lf->lno_s = lr->offset + lr->start;
1215                 if (lf->lno_s < 0)      /* Overflow */
1216                         lf->lno_s = INT_MAX;
1217                 lf->lno_e = lr->offset + lr->end;
1218                 if (lf->lno_e < 0)      /* Overflow */
1219                         lf->lno_e = INT_MAX;
1220                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1221                 lr->start = lf->lno_s;
1222                 lr->end = lf->lno_e;
1223                 if (dwarf_func_inline(sp_die)) {
1224                         struct dwarf_callback_param _param;
1225                         _param.data = (void *)lf;
1226                         _param.retval = 0;
1227                         dwarf_func_inline_instances(sp_die,
1228                                                     line_range_inline_cb,
1229                                                     &_param);
1230                         param->retval = _param.retval;
1231                 } else
1232                         param->retval = find_line_range_by_line(sp_die, lf);
1233                 return DWARF_CB_ABORT;
1234         }
1235         return DWARF_CB_OK;
1236 }
1237
1238 static int find_line_range_by_func(struct line_finder *lf)
1239 {
1240         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1241         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1242         return param.retval;
1243 }
1244
1245 int find_line_range(int fd, struct line_range *lr)
1246 {
1247         struct line_finder lf = {.lr = lr, .found = 0};
1248         int ret = 0;
1249         Dwarf_Off off = 0, noff;
1250         size_t cuhl;
1251         Dwarf_Die *diep;
1252         Dwarf *dbg;
1253
1254         dbg = dwarf_begin(fd, DWARF_C_READ);
1255         if (!dbg) {
1256                 pr_warning("No dwarf info found in the vmlinux - "
1257                         "please rebuild with CONFIG_DEBUG_INFO=y.\n");
1258                 return -EBADF;
1259         }
1260
1261         /* Loop on CUs (Compilation Unit) */
1262         while (!lf.found && ret >= 0) {
1263                 if (dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) != 0)
1264                         break;
1265
1266                 /* Get the DIE(Debugging Information Entry) of this CU */
1267                 diep = dwarf_offdie(dbg, off + cuhl, &lf.cu_die);
1268                 if (!diep)
1269                         continue;
1270
1271                 /* Check if target file is included. */
1272                 if (lr->file)
1273                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1274                 else
1275                         lf.fname = 0;
1276
1277                 if (!lr->file || lf.fname) {
1278                         if (lr->function)
1279                                 ret = find_line_range_by_func(&lf);
1280                         else {
1281                                 lf.lno_s = lr->start;
1282                                 lf.lno_e = lr->end;
1283                                 ret = find_line_range_by_line(NULL, &lf);
1284                         }
1285                 }
1286                 off = noff;
1287         }
1288         pr_debug("path: %lx\n", (unsigned long)lr->path);
1289         dwarf_end(dbg);
1290
1291         return (ret < 0) ? ret : lf.found;
1292 }
1293