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TOMOYO Linux Cross Reference
Linux/tools/perf/util/probe-finder.c

Version: ~ [ linux-4.18-rc1 ] ~ [ linux-4.17.2 ] ~ [ linux-4.16.16 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.50 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.109 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.138 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.113 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.57 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.27.62 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  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 <inttypes.h>
 23 #include <sys/utsname.h>
 24 #include <sys/types.h>
 25 #include <sys/stat.h>
 26 #include <fcntl.h>
 27 #include <errno.h>
 28 #include <stdio.h>
 29 #include <unistd.h>
 30 #include <stdlib.h>
 31 #include <string.h>
 32 #include <stdarg.h>
 33 #include <dwarf-regs.h>
 34 
 35 #include <linux/bitops.h>
 36 #include "event.h"
 37 #include "dso.h"
 38 #include "debug.h"
 39 #include "intlist.h"
 40 #include "util.h"
 41 #include "strlist.h"
 42 #include "symbol.h"
 43 #include "probe-finder.h"
 44 #include "probe-file.h"
 45 #include "string2.h"
 46 
 47 /* Kprobe tracer basic type is up to u64 */
 48 #define MAX_BASIC_TYPE_BITS     64
 49 
 50 /* Dwarf FL wrappers */
 51 static char *debuginfo_path;    /* Currently dummy */
 52 
 53 static const Dwfl_Callbacks offline_callbacks = {
 54         .find_debuginfo = dwfl_standard_find_debuginfo,
 55         .debuginfo_path = &debuginfo_path,
 56 
 57         .section_address = dwfl_offline_section_address,
 58 
 59         /* We use this table for core files too.  */
 60         .find_elf = dwfl_build_id_find_elf,
 61 };
 62 
 63 /* Get a Dwarf from offline image */
 64 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
 65                                          const char *path)
 66 {
 67         int fd;
 68 
 69         fd = open(path, O_RDONLY);
 70         if (fd < 0)
 71                 return fd;
 72 
 73         dbg->dwfl = dwfl_begin(&offline_callbacks);
 74         if (!dbg->dwfl)
 75                 goto error;
 76 
 77         dwfl_report_begin(dbg->dwfl);
 78         dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
 79         if (!dbg->mod)
 80                 goto error;
 81 
 82         dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
 83         if (!dbg->dbg)
 84                 goto error;
 85 
 86         dwfl_report_end(dbg->dwfl, NULL, NULL);
 87 
 88         return 0;
 89 error:
 90         if (dbg->dwfl)
 91                 dwfl_end(dbg->dwfl);
 92         else
 93                 close(fd);
 94         memset(dbg, 0, sizeof(*dbg));
 95 
 96         return -ENOENT;
 97 }
 98 
 99 static struct debuginfo *__debuginfo__new(const char *path)
100 {
101         struct debuginfo *dbg = zalloc(sizeof(*dbg));
102         if (!dbg)
103                 return NULL;
104 
105         if (debuginfo__init_offline_dwarf(dbg, path) < 0)
106                 zfree(&dbg);
107         if (dbg)
108                 pr_debug("Open Debuginfo file: %s\n", path);
109         return dbg;
110 }
111 
112 enum dso_binary_type distro_dwarf_types[] = {
113         DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
114         DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
115         DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
116         DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
117         DSO_BINARY_TYPE__NOT_FOUND,
118 };
119 
120 struct debuginfo *debuginfo__new(const char *path)
121 {
122         enum dso_binary_type *type;
123         char buf[PATH_MAX], nil = '\0';
124         struct dso *dso;
125         struct debuginfo *dinfo = NULL;
126 
127         /* Try to open distro debuginfo files */
128         dso = dso__new(path);
129         if (!dso)
130                 goto out;
131 
132         for (type = distro_dwarf_types;
133              !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
134              type++) {
135                 if (dso__read_binary_type_filename(dso, *type, &nil,
136                                                    buf, PATH_MAX) < 0)
137                         continue;
138                 dinfo = __debuginfo__new(buf);
139         }
140         dso__put(dso);
141 
142 out:
143         /* if failed to open all distro debuginfo, open given binary */
144         return dinfo ? : __debuginfo__new(path);
145 }
146 
147 void debuginfo__delete(struct debuginfo *dbg)
148 {
149         if (dbg) {
150                 if (dbg->dwfl)
151                         dwfl_end(dbg->dwfl);
152                 free(dbg);
153         }
154 }
155 
156 /*
157  * Probe finder related functions
158  */
159 
160 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
161 {
162         struct probe_trace_arg_ref *ref;
163         ref = zalloc(sizeof(struct probe_trace_arg_ref));
164         if (ref != NULL)
165                 ref->offset = offs;
166         return ref;
167 }
168 
169 /*
170  * Convert a location into trace_arg.
171  * If tvar == NULL, this just checks variable can be converted.
172  * If fentry == true and vr_die is a parameter, do huristic search
173  * for the location fuzzed by function entry mcount.
174  */
175 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
176                                      Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
177                                      unsigned int machine,
178                                      struct probe_trace_arg *tvar)
179 {
180         Dwarf_Attribute attr;
181         Dwarf_Addr tmp = 0;
182         Dwarf_Op *op;
183         size_t nops;
184         unsigned int regn;
185         Dwarf_Word offs = 0;
186         bool ref = false;
187         const char *regs;
188         int ret, ret2 = 0;
189 
190         if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
191                 goto static_var;
192 
193         /* TODO: handle more than 1 exprs */
194         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
195                 return -EINVAL; /* Broken DIE ? */
196         if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
197                 ret = dwarf_entrypc(sp_die, &tmp);
198                 if (ret)
199                         return -ENOENT;
200 
201                 if (probe_conf.show_location_range &&
202                         (dwarf_tag(vr_die) == DW_TAG_variable)) {
203                         ret2 = -ERANGE;
204                 } else if (addr != tmp ||
205                         dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
206                         return -ENOENT;
207                 }
208 
209                 ret = dwarf_highpc(sp_die, &tmp);
210                 if (ret)
211                         return -ENOENT;
212                 /*
213                  * This is fuzzed by fentry mcount. We try to find the
214                  * parameter location at the earliest address.
215                  */
216                 for (addr += 1; addr <= tmp; addr++) {
217                         if (dwarf_getlocation_addr(&attr, addr, &op,
218                                                    &nops, 1) > 0)
219                                 goto found;
220                 }
221                 return -ENOENT;
222         }
223 found:
224         if (nops == 0)
225                 /* TODO: Support const_value */
226                 return -ENOENT;
227 
228         if (op->atom == DW_OP_addr) {
229 static_var:
230                 if (!tvar)
231                         return ret2;
232                 /* Static variables on memory (not stack), make @varname */
233                 ret = strlen(dwarf_diename(vr_die));
234                 tvar->value = zalloc(ret + 2);
235                 if (tvar->value == NULL)
236                         return -ENOMEM;
237                 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
238                 tvar->ref = alloc_trace_arg_ref((long)offs);
239                 if (tvar->ref == NULL)
240                         return -ENOMEM;
241                 return ret2;
242         }
243 
244         /* If this is based on frame buffer, set the offset */
245         if (op->atom == DW_OP_fbreg) {
246                 if (fb_ops == NULL)
247                         return -ENOTSUP;
248                 ref = true;
249                 offs = op->number;
250                 op = &fb_ops[0];
251         }
252 
253         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
254                 regn = op->atom - DW_OP_breg0;
255                 offs += op->number;
256                 ref = true;
257         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
258                 regn = op->atom - DW_OP_reg0;
259         } else if (op->atom == DW_OP_bregx) {
260                 regn = op->number;
261                 offs += op->number2;
262                 ref = true;
263         } else if (op->atom == DW_OP_regx) {
264                 regn = op->number;
265         } else {
266                 pr_debug("DW_OP %x is not supported.\n", op->atom);
267                 return -ENOTSUP;
268         }
269 
270         if (!tvar)
271                 return ret2;
272 
273         regs = get_dwarf_regstr(regn, machine);
274         if (!regs) {
275                 /* This should be a bug in DWARF or this tool */
276                 pr_warning("Mapping for the register number %u "
277                            "missing on this architecture.\n", regn);
278                 return -ENOTSUP;
279         }
280 
281         tvar->value = strdup(regs);
282         if (tvar->value == NULL)
283                 return -ENOMEM;
284 
285         if (ref) {
286                 tvar->ref = alloc_trace_arg_ref((long)offs);
287                 if (tvar->ref == NULL)
288                         return -ENOMEM;
289         }
290         return ret2;
291 }
292 
293 #define BYTES_TO_BITS(nb)       ((nb) * BITS_PER_LONG / sizeof(long))
294 
295 static int convert_variable_type(Dwarf_Die *vr_die,
296                                  struct probe_trace_arg *tvar,
297                                  const char *cast)
298 {
299         struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
300         Dwarf_Die type;
301         char buf[16];
302         char sbuf[STRERR_BUFSIZE];
303         int bsize, boffs, total;
304         int ret;
305         char prefix;
306 
307         /* TODO: check all types */
308         if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "x") != 0 &&
309             strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) {
310                 /* Non string type is OK */
311                 /* and respect signedness/hexadecimal cast */
312                 tvar->type = strdup(cast);
313                 return (tvar->type == NULL) ? -ENOMEM : 0;
314         }
315 
316         bsize = dwarf_bitsize(vr_die);
317         if (bsize > 0) {
318                 /* This is a bitfield */
319                 boffs = dwarf_bitoffset(vr_die);
320                 total = dwarf_bytesize(vr_die);
321                 if (boffs < 0 || total < 0)
322                         return -ENOENT;
323                 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
324                                 BYTES_TO_BITS(total));
325                 goto formatted;
326         }
327 
328         if (die_get_real_type(vr_die, &type) == NULL) {
329                 pr_warning("Failed to get a type information of %s.\n",
330                            dwarf_diename(vr_die));
331                 return -ENOENT;
332         }
333 
334         pr_debug("%s type is %s.\n",
335                  dwarf_diename(vr_die), dwarf_diename(&type));
336 
337         if (cast && strcmp(cast, "string") == 0) {      /* String type */
338                 ret = dwarf_tag(&type);
339                 if (ret != DW_TAG_pointer_type &&
340                     ret != DW_TAG_array_type) {
341                         pr_warning("Failed to cast into string: "
342                                    "%s(%s) is not a pointer nor array.\n",
343                                    dwarf_diename(vr_die), dwarf_diename(&type));
344                         return -EINVAL;
345                 }
346                 if (die_get_real_type(&type, &type) == NULL) {
347                         pr_warning("Failed to get a type"
348                                    " information.\n");
349                         return -ENOENT;
350                 }
351                 if (ret == DW_TAG_pointer_type) {
352                         while (*ref_ptr)
353                                 ref_ptr = &(*ref_ptr)->next;
354                         /* Add new reference with offset +0 */
355                         *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
356                         if (*ref_ptr == NULL) {
357                                 pr_warning("Out of memory error\n");
358                                 return -ENOMEM;
359                         }
360                 }
361                 if (!die_compare_name(&type, "char") &&
362                     !die_compare_name(&type, "unsigned char")) {
363                         pr_warning("Failed to cast into string: "
364                                    "%s is not (unsigned) char *.\n",
365                                    dwarf_diename(vr_die));
366                         return -EINVAL;
367                 }
368                 tvar->type = strdup(cast);
369                 return (tvar->type == NULL) ? -ENOMEM : 0;
370         }
371 
372         if (cast && (strcmp(cast, "u") == 0))
373                 prefix = 'u';
374         else if (cast && (strcmp(cast, "s") == 0))
375                 prefix = 's';
376         else if (cast && (strcmp(cast, "x") == 0) &&
377                  probe_type_is_available(PROBE_TYPE_X))
378                 prefix = 'x';
379         else
380                 prefix = die_is_signed_type(&type) ? 's' :
381                          probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u';
382 
383         ret = dwarf_bytesize(&type);
384         if (ret <= 0)
385                 /* No size ... try to use default type */
386                 return 0;
387         ret = BYTES_TO_BITS(ret);
388 
389         /* Check the bitwidth */
390         if (ret > MAX_BASIC_TYPE_BITS) {
391                 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
392                         dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
393                 ret = MAX_BASIC_TYPE_BITS;
394         }
395         ret = snprintf(buf, 16, "%c%d", prefix, ret);
396 
397 formatted:
398         if (ret < 0 || ret >= 16) {
399                 if (ret >= 16)
400                         ret = -E2BIG;
401                 pr_warning("Failed to convert variable type: %s\n",
402                            str_error_r(-ret, sbuf, sizeof(sbuf)));
403                 return ret;
404         }
405         tvar->type = strdup(buf);
406         if (tvar->type == NULL)
407                 return -ENOMEM;
408         return 0;
409 }
410 
411 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
412                                     struct perf_probe_arg_field *field,
413                                     struct probe_trace_arg_ref **ref_ptr,
414                                     Dwarf_Die *die_mem)
415 {
416         struct probe_trace_arg_ref *ref = *ref_ptr;
417         Dwarf_Die type;
418         Dwarf_Word offs;
419         int ret, tag;
420 
421         pr_debug("converting %s in %s\n", field->name, varname);
422         if (die_get_real_type(vr_die, &type) == NULL) {
423                 pr_warning("Failed to get the type of %s.\n", varname);
424                 return -ENOENT;
425         }
426         pr_debug2("Var real type: %s (%x)\n", dwarf_diename(&type),
427                   (unsigned)dwarf_dieoffset(&type));
428         tag = dwarf_tag(&type);
429 
430         if (field->name[0] == '[' &&
431             (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
432                 /* Save original type for next field or type */
433                 memcpy(die_mem, &type, sizeof(*die_mem));
434                 /* Get the type of this array */
435                 if (die_get_real_type(&type, &type) == NULL) {
436                         pr_warning("Failed to get the type of %s.\n", varname);
437                         return -ENOENT;
438                 }
439                 pr_debug2("Array real type: %s (%x)\n", dwarf_diename(&type),
440                          (unsigned)dwarf_dieoffset(&type));
441                 if (tag == DW_TAG_pointer_type) {
442                         ref = zalloc(sizeof(struct probe_trace_arg_ref));
443                         if (ref == NULL)
444                                 return -ENOMEM;
445                         if (*ref_ptr)
446                                 (*ref_ptr)->next = ref;
447                         else
448                                 *ref_ptr = ref;
449                 }
450                 ref->offset += dwarf_bytesize(&type) * field->index;
451                 goto next;
452         } else if (tag == DW_TAG_pointer_type) {
453                 /* Check the pointer and dereference */
454                 if (!field->ref) {
455                         pr_err("Semantic error: %s must be referred by '->'\n",
456                                field->name);
457                         return -EINVAL;
458                 }
459                 /* Get the type pointed by this pointer */
460                 if (die_get_real_type(&type, &type) == NULL) {
461                         pr_warning("Failed to get the type of %s.\n", varname);
462                         return -ENOENT;
463                 }
464                 /* Verify it is a data structure  */
465                 tag = dwarf_tag(&type);
466                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
467                         pr_warning("%s is not a data structure nor a union.\n",
468                                    varname);
469                         return -EINVAL;
470                 }
471 
472                 ref = zalloc(sizeof(struct probe_trace_arg_ref));
473                 if (ref == NULL)
474                         return -ENOMEM;
475                 if (*ref_ptr)
476                         (*ref_ptr)->next = ref;
477                 else
478                         *ref_ptr = ref;
479         } else {
480                 /* Verify it is a data structure  */
481                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
482                         pr_warning("%s is not a data structure nor a union.\n",
483                                    varname);
484                         return -EINVAL;
485                 }
486                 if (field->name[0] == '[') {
487                         pr_err("Semantic error: %s is not a pointer"
488                                " nor array.\n", varname);
489                         return -EINVAL;
490                 }
491                 /* While prcessing unnamed field, we don't care about this */
492                 if (field->ref && dwarf_diename(vr_die)) {
493                         pr_err("Semantic error: %s must be referred by '.'\n",
494                                field->name);
495                         return -EINVAL;
496                 }
497                 if (!ref) {
498                         pr_warning("Structure on a register is not "
499                                    "supported yet.\n");
500                         return -ENOTSUP;
501                 }
502         }
503 
504         if (die_find_member(&type, field->name, die_mem) == NULL) {
505                 pr_warning("%s(type:%s) has no member %s.\n", varname,
506                            dwarf_diename(&type), field->name);
507                 return -EINVAL;
508         }
509 
510         /* Get the offset of the field */
511         if (tag == DW_TAG_union_type) {
512                 offs = 0;
513         } else {
514                 ret = die_get_data_member_location(die_mem, &offs);
515                 if (ret < 0) {
516                         pr_warning("Failed to get the offset of %s.\n",
517                                    field->name);
518                         return ret;
519                 }
520         }
521         ref->offset += (long)offs;
522 
523         /* If this member is unnamed, we need to reuse this field */
524         if (!dwarf_diename(die_mem))
525                 return convert_variable_fields(die_mem, varname, field,
526                                                 &ref, die_mem);
527 
528 next:
529         /* Converting next field */
530         if (field->next)
531                 return convert_variable_fields(die_mem, field->name,
532                                         field->next, &ref, die_mem);
533         else
534                 return 0;
535 }
536 
537 /* Show a variables in kprobe event format */
538 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
539 {
540         Dwarf_Die die_mem;
541         int ret;
542 
543         pr_debug("Converting variable %s into trace event.\n",
544                  dwarf_diename(vr_die));
545 
546         ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
547                                         &pf->sp_die, pf->machine, pf->tvar);
548         if (ret == -ENOENT || ret == -EINVAL) {
549                 pr_err("Failed to find the location of the '%s' variable at this address.\n"
550                        " Perhaps it has been optimized out.\n"
551                        " Use -V with the --range option to show '%s' location range.\n",
552                        pf->pvar->var, pf->pvar->var);
553         } else if (ret == -ENOTSUP)
554                 pr_err("Sorry, we don't support this variable location yet.\n");
555         else if (ret == 0 && pf->pvar->field) {
556                 ret = convert_variable_fields(vr_die, pf->pvar->var,
557                                               pf->pvar->field, &pf->tvar->ref,
558                                               &die_mem);
559                 vr_die = &die_mem;
560         }
561         if (ret == 0)
562                 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
563         /* *expr will be cached in libdw. Don't free it. */
564         return ret;
565 }
566 
567 /* Find a variable in a scope DIE */
568 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
569 {
570         Dwarf_Die vr_die;
571         char *buf, *ptr;
572         int ret = 0;
573 
574         /* Copy raw parameters */
575         if (!is_c_varname(pf->pvar->var))
576                 return copy_to_probe_trace_arg(pf->tvar, pf->pvar);
577 
578         if (pf->pvar->name)
579                 pf->tvar->name = strdup(pf->pvar->name);
580         else {
581                 buf = synthesize_perf_probe_arg(pf->pvar);
582                 if (!buf)
583                         return -ENOMEM;
584                 ptr = strchr(buf, ':'); /* Change type separator to _ */
585                 if (ptr)
586                         *ptr = '_';
587                 pf->tvar->name = buf;
588         }
589         if (pf->tvar->name == NULL)
590                 return -ENOMEM;
591 
592         pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
593         /* Search child die for local variables and parameters. */
594         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
595                 /* Search again in global variables */
596                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
597                                                 0, &vr_die)) {
598                         pr_warning("Failed to find '%s' in this function.\n",
599                                    pf->pvar->var);
600                         ret = -ENOENT;
601                 }
602         }
603         if (ret >= 0)
604                 ret = convert_variable(&vr_die, pf);
605 
606         return ret;
607 }
608 
609 /* Convert subprogram DIE to trace point */
610 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
611                                   Dwarf_Addr paddr, bool retprobe,
612                                   const char *function,
613                                   struct probe_trace_point *tp)
614 {
615         Dwarf_Addr eaddr, highaddr;
616         GElf_Sym sym;
617         const char *symbol;
618 
619         /* Verify the address is correct */
620         if (dwarf_entrypc(sp_die, &eaddr) != 0) {
621                 pr_warning("Failed to get entry address of %s\n",
622                            dwarf_diename(sp_die));
623                 return -ENOENT;
624         }
625         if (dwarf_highpc(sp_die, &highaddr) != 0) {
626                 pr_warning("Failed to get end address of %s\n",
627                            dwarf_diename(sp_die));
628                 return -ENOENT;
629         }
630         if (paddr > highaddr) {
631                 pr_warning("Offset specified is greater than size of %s\n",
632                            dwarf_diename(sp_die));
633                 return -EINVAL;
634         }
635 
636         symbol = dwarf_diename(sp_die);
637         if (!symbol) {
638                 /* Try to get the symbol name from symtab */
639                 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
640                 if (!symbol) {
641                         pr_warning("Failed to find symbol at 0x%lx\n",
642                                    (unsigned long)paddr);
643                         return -ENOENT;
644                 }
645                 eaddr = sym.st_value;
646         }
647         tp->offset = (unsigned long)(paddr - eaddr);
648         tp->address = (unsigned long)paddr;
649         tp->symbol = strdup(symbol);
650         if (!tp->symbol)
651                 return -ENOMEM;
652 
653         /* Return probe must be on the head of a subprogram */
654         if (retprobe) {
655                 if (eaddr != paddr) {
656                         pr_warning("Failed to find \"%s%%return\",\n"
657                                    " because %s is an inlined function and"
658                                    " has no return point.\n", function,
659                                    function);
660                         return -EINVAL;
661                 }
662                 tp->retprobe = true;
663         }
664 
665         return 0;
666 }
667 
668 /* Call probe_finder callback with scope DIE */
669 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
670 {
671         Dwarf_Attribute fb_attr;
672         Dwarf_Frame *frame = NULL;
673         size_t nops;
674         int ret;
675 
676         if (!sc_die) {
677                 pr_err("Caller must pass a scope DIE. Program error.\n");
678                 return -EINVAL;
679         }
680 
681         /* If not a real subprogram, find a real one */
682         if (!die_is_func_def(sc_die)) {
683                 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
684                         if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
685                                 pr_warning("Ignoring tail call from %s\n",
686                                                 dwarf_diename(&pf->sp_die));
687                                 return 0;
688                         } else {
689                                 pr_warning("Failed to find probe point in any "
690                                            "functions.\n");
691                                 return -ENOENT;
692                         }
693                 }
694         } else
695                 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
696 
697         /* Get the frame base attribute/ops from subprogram */
698         dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
699         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
700         if (ret <= 0 || nops == 0) {
701                 pf->fb_ops = NULL;
702 #if _ELFUTILS_PREREQ(0, 142)
703         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
704                    (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) {
705                 if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 &&
706                      (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) ||
707                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
708                         pr_warning("Failed to get call frame on 0x%jx\n",
709                                    (uintmax_t)pf->addr);
710                         free(frame);
711                         return -ENOENT;
712                 }
713 #endif
714         }
715 
716         /* Call finder's callback handler */
717         ret = pf->callback(sc_die, pf);
718 
719         /* Since *pf->fb_ops can be a part of frame. we should free it here. */
720         free(frame);
721         pf->fb_ops = NULL;
722 
723         return ret;
724 }
725 
726 struct find_scope_param {
727         const char *function;
728         const char *file;
729         int line;
730         int diff;
731         Dwarf_Die *die_mem;
732         bool found;
733 };
734 
735 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
736 {
737         struct find_scope_param *fsp = data;
738         const char *file;
739         int lno;
740 
741         /* Skip if declared file name does not match */
742         if (fsp->file) {
743                 file = dwarf_decl_file(fn_die);
744                 if (!file || strcmp(fsp->file, file) != 0)
745                         return 0;
746         }
747         /* If the function name is given, that's what user expects */
748         if (fsp->function) {
749                 if (die_match_name(fn_die, fsp->function)) {
750                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
751                         fsp->found = true;
752                         return 1;
753                 }
754         } else {
755                 /* With the line number, find the nearest declared DIE */
756                 dwarf_decl_line(fn_die, &lno);
757                 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
758                         /* Keep a candidate and continue */
759                         fsp->diff = fsp->line - lno;
760                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
761                         fsp->found = true;
762                 }
763         }
764         return 0;
765 }
766 
767 /* Find an appropriate scope fits to given conditions */
768 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
769 {
770         struct find_scope_param fsp = {
771                 .function = pf->pev->point.function,
772                 .file = pf->fname,
773                 .line = pf->lno,
774                 .diff = INT_MAX,
775                 .die_mem = die_mem,
776                 .found = false,
777         };
778 
779         cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
780 
781         return fsp.found ? die_mem : NULL;
782 }
783 
784 static int probe_point_line_walker(const char *fname, int lineno,
785                                    Dwarf_Addr addr, void *data)
786 {
787         struct probe_finder *pf = data;
788         Dwarf_Die *sc_die, die_mem;
789         int ret;
790 
791         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
792                 return 0;
793 
794         pf->addr = addr;
795         sc_die = find_best_scope(pf, &die_mem);
796         if (!sc_die) {
797                 pr_warning("Failed to find scope of probe point.\n");
798                 return -ENOENT;
799         }
800 
801         ret = call_probe_finder(sc_die, pf);
802 
803         /* Continue if no error, because the line will be in inline function */
804         return ret < 0 ? ret : 0;
805 }
806 
807 /* Find probe point from its line number */
808 static int find_probe_point_by_line(struct probe_finder *pf)
809 {
810         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
811 }
812 
813 /* Find lines which match lazy pattern */
814 static int find_lazy_match_lines(struct intlist *list,
815                                  const char *fname, const char *pat)
816 {
817         FILE *fp;
818         char *line = NULL;
819         size_t line_len;
820         ssize_t len;
821         int count = 0, linenum = 1;
822         char sbuf[STRERR_BUFSIZE];
823 
824         fp = fopen(fname, "r");
825         if (!fp) {
826                 pr_warning("Failed to open %s: %s\n", fname,
827                            str_error_r(errno, sbuf, sizeof(sbuf)));
828                 return -errno;
829         }
830 
831         while ((len = getline(&line, &line_len, fp)) > 0) {
832 
833                 if (line[len - 1] == '\n')
834                         line[len - 1] = '\0';
835 
836                 if (strlazymatch(line, pat)) {
837                         intlist__add(list, linenum);
838                         count++;
839                 }
840                 linenum++;
841         }
842 
843         if (ferror(fp))
844                 count = -errno;
845         free(line);
846         fclose(fp);
847 
848         if (count == 0)
849                 pr_debug("No matched lines found in %s.\n", fname);
850         return count;
851 }
852 
853 static int probe_point_lazy_walker(const char *fname, int lineno,
854                                    Dwarf_Addr addr, void *data)
855 {
856         struct probe_finder *pf = data;
857         Dwarf_Die *sc_die, die_mem;
858         int ret;
859 
860         if (!intlist__has_entry(pf->lcache, lineno) ||
861             strtailcmp(fname, pf->fname) != 0)
862                 return 0;
863 
864         pr_debug("Probe line found: line:%d addr:0x%llx\n",
865                  lineno, (unsigned long long)addr);
866         pf->addr = addr;
867         pf->lno = lineno;
868         sc_die = find_best_scope(pf, &die_mem);
869         if (!sc_die) {
870                 pr_warning("Failed to find scope of probe point.\n");
871                 return -ENOENT;
872         }
873 
874         ret = call_probe_finder(sc_die, pf);
875 
876         /*
877          * Continue if no error, because the lazy pattern will match
878          * to other lines
879          */
880         return ret < 0 ? ret : 0;
881 }
882 
883 /* Find probe points from lazy pattern  */
884 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
885 {
886         int ret = 0;
887         char *fpath;
888 
889         if (intlist__empty(pf->lcache)) {
890                 const char *comp_dir;
891 
892                 comp_dir = cu_get_comp_dir(&pf->cu_die);
893                 ret = get_real_path(pf->fname, comp_dir, &fpath);
894                 if (ret < 0) {
895                         pr_warning("Failed to find source file path.\n");
896                         return ret;
897                 }
898 
899                 /* Matching lazy line pattern */
900                 ret = find_lazy_match_lines(pf->lcache, fpath,
901                                             pf->pev->point.lazy_line);
902                 free(fpath);
903                 if (ret <= 0)
904                         return ret;
905         }
906 
907         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
908 }
909 
910 static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
911 {
912         struct perf_probe_point *pp = &pf->pev->point;
913 
914         /* Not uprobe? */
915         if (!pf->pev->uprobes)
916                 return;
917 
918         /* Compiled with optimization? */
919         if (die_is_optimized_target(&pf->cu_die))
920                 return;
921 
922         /* Don't know entrypc? */
923         if (!pf->addr)
924                 return;
925 
926         /* Only FUNC and FUNC@SRC are eligible. */
927         if (!pp->function || pp->line || pp->retprobe || pp->lazy_line ||
928             pp->offset || pp->abs_address)
929                 return;
930 
931         /* Not interested in func parameter? */
932         if (!perf_probe_with_var(pf->pev))
933                 return;
934 
935         pr_info("Target program is compiled without optimization. Skipping prologue.\n"
936                 "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
937                 pf->addr);
938 
939         die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
940 }
941 
942 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
943 {
944         struct probe_finder *pf = data;
945         struct perf_probe_point *pp = &pf->pev->point;
946         Dwarf_Addr addr;
947         int ret;
948 
949         if (pp->lazy_line)
950                 ret = find_probe_point_lazy(in_die, pf);
951         else {
952                 /* Get probe address */
953                 if (dwarf_entrypc(in_die, &addr) != 0) {
954                         pr_warning("Failed to get entry address of %s.\n",
955                                    dwarf_diename(in_die));
956                         return -ENOENT;
957                 }
958                 if (addr == 0) {
959                         pr_debug("%s has no valid entry address. skipped.\n",
960                                  dwarf_diename(in_die));
961                         return -ENOENT;
962                 }
963                 pf->addr = addr;
964                 pf->addr += pp->offset;
965                 pr_debug("found inline addr: 0x%jx\n",
966                          (uintmax_t)pf->addr);
967 
968                 ret = call_probe_finder(in_die, pf);
969         }
970 
971         return ret;
972 }
973 
974 /* Callback parameter with return value for libdw */
975 struct dwarf_callback_param {
976         void *data;
977         int retval;
978 };
979 
980 /* Search function from function name */
981 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
982 {
983         struct dwarf_callback_param *param = data;
984         struct probe_finder *pf = param->data;
985         struct perf_probe_point *pp = &pf->pev->point;
986 
987         /* Check tag and diename */
988         if (!die_is_func_def(sp_die) ||
989             !die_match_name(sp_die, pp->function))
990                 return DWARF_CB_OK;
991 
992         /* Check declared file */
993         if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
994                 return DWARF_CB_OK;
995 
996         pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die),
997                  (unsigned long)dwarf_dieoffset(sp_die));
998         pf->fname = dwarf_decl_file(sp_die);
999         if (pp->line) { /* Function relative line */
1000                 dwarf_decl_line(sp_die, &pf->lno);
1001                 pf->lno += pp->line;
1002                 param->retval = find_probe_point_by_line(pf);
1003         } else if (die_is_func_instance(sp_die)) {
1004                 /* Instances always have the entry address */
1005                 dwarf_entrypc(sp_die, &pf->addr);
1006                 /* But in some case the entry address is 0 */
1007                 if (pf->addr == 0) {
1008                         pr_debug("%s has no entry PC. Skipped\n",
1009                                  dwarf_diename(sp_die));
1010                         param->retval = 0;
1011                 /* Real function */
1012                 } else if (pp->lazy_line)
1013                         param->retval = find_probe_point_lazy(sp_die, pf);
1014                 else {
1015                         skip_prologue(sp_die, pf);
1016                         pf->addr += pp->offset;
1017                         /* TODO: Check the address in this function */
1018                         param->retval = call_probe_finder(sp_die, pf);
1019                 }
1020         } else if (!probe_conf.no_inlines) {
1021                 /* Inlined function: search instances */
1022                 param->retval = die_walk_instances(sp_die,
1023                                         probe_point_inline_cb, (void *)pf);
1024                 /* This could be a non-existed inline definition */
1025                 if (param->retval == -ENOENT)
1026                         param->retval = 0;
1027         }
1028 
1029         /* We need to find other candidates */
1030         if (strisglob(pp->function) && param->retval >= 0) {
1031                 param->retval = 0;      /* We have to clear the result */
1032                 return DWARF_CB_OK;
1033         }
1034 
1035         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
1036 }
1037 
1038 static int find_probe_point_by_func(struct probe_finder *pf)
1039 {
1040         struct dwarf_callback_param _param = {.data = (void *)pf,
1041                                               .retval = 0};
1042         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
1043         return _param.retval;
1044 }
1045 
1046 struct pubname_callback_param {
1047         char *function;
1048         char *file;
1049         Dwarf_Die *cu_die;
1050         Dwarf_Die *sp_die;
1051         int found;
1052 };
1053 
1054 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1055 {
1056         struct pubname_callback_param *param = data;
1057 
1058         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1059                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1060                         return DWARF_CB_OK;
1061 
1062                 if (die_match_name(param->sp_die, param->function)) {
1063                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1064                                 return DWARF_CB_OK;
1065 
1066                         if (param->file &&
1067                             strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1068                                 return DWARF_CB_OK;
1069 
1070                         param->found = 1;
1071                         return DWARF_CB_ABORT;
1072                 }
1073         }
1074 
1075         return DWARF_CB_OK;
1076 }
1077 
1078 static int debuginfo__find_probe_location(struct debuginfo *dbg,
1079                                   struct probe_finder *pf)
1080 {
1081         struct perf_probe_point *pp = &pf->pev->point;
1082         Dwarf_Off off, noff;
1083         size_t cuhl;
1084         Dwarf_Die *diep;
1085         int ret = 0;
1086 
1087         off = 0;
1088         pf->lcache = intlist__new(NULL);
1089         if (!pf->lcache)
1090                 return -ENOMEM;
1091 
1092         /* Fastpath: lookup by function name from .debug_pubnames section */
1093         if (pp->function && !strisglob(pp->function)) {
1094                 struct pubname_callback_param pubname_param = {
1095                         .function = pp->function,
1096                         .file     = pp->file,
1097                         .cu_die   = &pf->cu_die,
1098                         .sp_die   = &pf->sp_die,
1099                         .found    = 0,
1100                 };
1101                 struct dwarf_callback_param probe_param = {
1102                         .data = pf,
1103                 };
1104 
1105                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1106                                   &pubname_param, 0);
1107                 if (pubname_param.found) {
1108                         ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1109                         if (ret)
1110                                 goto found;
1111                 }
1112         }
1113 
1114         /* Loop on CUs (Compilation Unit) */
1115         while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1116                 /* Get the DIE(Debugging Information Entry) of this CU */
1117                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1118                 if (!diep)
1119                         continue;
1120 
1121                 /* Check if target file is included. */
1122                 if (pp->file)
1123                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1124                 else
1125                         pf->fname = NULL;
1126 
1127                 if (!pp->file || pf->fname) {
1128                         if (pp->function)
1129                                 ret = find_probe_point_by_func(pf);
1130                         else if (pp->lazy_line)
1131                                 ret = find_probe_point_lazy(&pf->cu_die, pf);
1132                         else {
1133                                 pf->lno = pp->line;
1134                                 ret = find_probe_point_by_line(pf);
1135                         }
1136                         if (ret < 0)
1137                                 break;
1138                 }
1139                 off = noff;
1140         }
1141 
1142 found:
1143         intlist__delete(pf->lcache);
1144         pf->lcache = NULL;
1145 
1146         return ret;
1147 }
1148 
1149 /* Find probe points from debuginfo */
1150 static int debuginfo__find_probes(struct debuginfo *dbg,
1151                                   struct probe_finder *pf)
1152 {
1153         int ret = 0;
1154         Elf *elf;
1155         GElf_Ehdr ehdr;
1156 
1157         if (pf->cfi_eh || pf->cfi_dbg)
1158                 return debuginfo__find_probe_location(dbg, pf);
1159 
1160         /* Get the call frame information from this dwarf */
1161         elf = dwarf_getelf(dbg->dbg);
1162         if (elf == NULL)
1163                 return -EINVAL;
1164 
1165         if (gelf_getehdr(elf, &ehdr) == NULL)
1166                 return -EINVAL;
1167 
1168         pf->machine = ehdr.e_machine;
1169 
1170 #if _ELFUTILS_PREREQ(0, 142)
1171         do {
1172                 GElf_Shdr shdr;
1173 
1174                 if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1175                     shdr.sh_type == SHT_PROGBITS)
1176                         pf->cfi_eh = dwarf_getcfi_elf(elf);
1177 
1178                 pf->cfi_dbg = dwarf_getcfi(dbg->dbg);
1179         } while (0);
1180 #endif
1181 
1182         ret = debuginfo__find_probe_location(dbg, pf);
1183         return ret;
1184 }
1185 
1186 struct local_vars_finder {
1187         struct probe_finder *pf;
1188         struct perf_probe_arg *args;
1189         bool vars;
1190         int max_args;
1191         int nargs;
1192         int ret;
1193 };
1194 
1195 /* Collect available variables in this scope */
1196 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1197 {
1198         struct local_vars_finder *vf = data;
1199         struct probe_finder *pf = vf->pf;
1200         int tag;
1201 
1202         tag = dwarf_tag(die_mem);
1203         if (tag == DW_TAG_formal_parameter ||
1204             (tag == DW_TAG_variable && vf->vars)) {
1205                 if (convert_variable_location(die_mem, vf->pf->addr,
1206                                               vf->pf->fb_ops, &pf->sp_die,
1207                                               pf->machine, NULL) == 0) {
1208                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1209                         if (vf->args[vf->nargs].var == NULL) {
1210                                 vf->ret = -ENOMEM;
1211                                 return DIE_FIND_CB_END;
1212                         }
1213                         pr_debug(" %s", vf->args[vf->nargs].var);
1214                         vf->nargs++;
1215                 }
1216         }
1217 
1218         if (dwarf_haspc(die_mem, vf->pf->addr))
1219                 return DIE_FIND_CB_CONTINUE;
1220         else
1221                 return DIE_FIND_CB_SIBLING;
1222 }
1223 
1224 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1225                              struct perf_probe_arg *args)
1226 {
1227         Dwarf_Die die_mem;
1228         int i;
1229         int n = 0;
1230         struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1231                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1232 
1233         for (i = 0; i < pf->pev->nargs; i++) {
1234                 /* var never be NULL */
1235                 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1236                         vf.vars = true;
1237                 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1238                         /* Copy normal argument */
1239                         args[n] = pf->pev->args[i];
1240                         n++;
1241                         continue;
1242                 }
1243                 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1244                 vf.nargs = n;
1245                 /* Special local variables */
1246                 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1247                                &die_mem);
1248                 pr_debug(" (%d)\n", vf.nargs - n);
1249                 if (vf.ret < 0)
1250                         return vf.ret;
1251                 n = vf.nargs;
1252         }
1253         return n;
1254 }
1255 
1256 /* Add a found probe point into trace event list */
1257 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1258 {
1259         struct trace_event_finder *tf =
1260                         container_of(pf, struct trace_event_finder, pf);
1261         struct perf_probe_point *pp = &pf->pev->point;
1262         struct probe_trace_event *tev;
1263         struct perf_probe_arg *args = NULL;
1264         int ret, i;
1265 
1266         /* Check number of tevs */
1267         if (tf->ntevs == tf->max_tevs) {
1268                 pr_warning("Too many( > %d) probe point found.\n",
1269                            tf->max_tevs);
1270                 return -ERANGE;
1271         }
1272         tev = &tf->tevs[tf->ntevs++];
1273 
1274         /* Trace point should be converted from subprogram DIE */
1275         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1276                                      pp->retprobe, pp->function, &tev->point);
1277         if (ret < 0)
1278                 goto end;
1279 
1280         tev->point.realname = strdup(dwarf_diename(sc_die));
1281         if (!tev->point.realname) {
1282                 ret = -ENOMEM;
1283                 goto end;
1284         }
1285 
1286         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1287                  tev->point.offset);
1288 
1289         /* Expand special probe argument if exist */
1290         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1291         if (args == NULL) {
1292                 ret = -ENOMEM;
1293                 goto end;
1294         }
1295 
1296         ret = expand_probe_args(sc_die, pf, args);
1297         if (ret < 0)
1298                 goto end;
1299 
1300         tev->nargs = ret;
1301         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1302         if (tev->args == NULL) {
1303                 ret = -ENOMEM;
1304                 goto end;
1305         }
1306 
1307         /* Find each argument */
1308         for (i = 0; i < tev->nargs; i++) {
1309                 pf->pvar = &args[i];
1310                 pf->tvar = &tev->args[i];
1311                 /* Variable should be found from scope DIE */
1312                 ret = find_variable(sc_die, pf);
1313                 if (ret != 0)
1314                         break;
1315         }
1316 
1317 end:
1318         if (ret) {
1319                 clear_probe_trace_event(tev);
1320                 tf->ntevs--;
1321         }
1322         free(args);
1323         return ret;
1324 }
1325 
1326 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1327 int debuginfo__find_trace_events(struct debuginfo *dbg,
1328                                  struct perf_probe_event *pev,
1329                                  struct probe_trace_event **tevs)
1330 {
1331         struct trace_event_finder tf = {
1332                         .pf = {.pev = pev, .callback = add_probe_trace_event},
1333                         .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1334         int ret, i;
1335 
1336         /* Allocate result tevs array */
1337         *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1338         if (*tevs == NULL)
1339                 return -ENOMEM;
1340 
1341         tf.tevs = *tevs;
1342         tf.ntevs = 0;
1343 
1344         ret = debuginfo__find_probes(dbg, &tf.pf);
1345         if (ret < 0) {
1346                 for (i = 0; i < tf.ntevs; i++)
1347                         clear_probe_trace_event(&tf.tevs[i]);
1348                 zfree(tevs);
1349                 return ret;
1350         }
1351 
1352         return (ret < 0) ? ret : tf.ntevs;
1353 }
1354 
1355 /* Collect available variables in this scope */
1356 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1357 {
1358         struct available_var_finder *af = data;
1359         struct variable_list *vl;
1360         struct strbuf buf = STRBUF_INIT;
1361         int tag, ret;
1362 
1363         vl = &af->vls[af->nvls - 1];
1364 
1365         tag = dwarf_tag(die_mem);
1366         if (tag == DW_TAG_formal_parameter ||
1367             tag == DW_TAG_variable) {
1368                 ret = convert_variable_location(die_mem, af->pf.addr,
1369                                                 af->pf.fb_ops, &af->pf.sp_die,
1370                                                 af->pf.machine, NULL);
1371                 if (ret == 0 || ret == -ERANGE) {
1372                         int ret2;
1373                         bool externs = !af->child;
1374 
1375                         if (strbuf_init(&buf, 64) < 0)
1376                                 goto error;
1377 
1378                         if (probe_conf.show_location_range) {
1379                                 if (!externs)
1380                                         ret2 = strbuf_add(&buf,
1381                                                 ret ? "[INV]\t" : "[VAL]\t", 6);
1382                                 else
1383                                         ret2 = strbuf_add(&buf, "[EXT]\t", 6);
1384                                 if (ret2)
1385                                         goto error;
1386                         }
1387 
1388                         ret2 = die_get_varname(die_mem, &buf);
1389 
1390                         if (!ret2 && probe_conf.show_location_range &&
1391                                 !externs) {
1392                                 if (strbuf_addch(&buf, '\t') < 0)
1393                                         goto error;
1394                                 ret2 = die_get_var_range(&af->pf.sp_die,
1395                                                         die_mem, &buf);
1396                         }
1397 
1398                         pr_debug("Add new var: %s\n", buf.buf);
1399                         if (ret2 == 0) {
1400                                 strlist__add(vl->vars,
1401                                         strbuf_detach(&buf, NULL));
1402                         }
1403                         strbuf_release(&buf);
1404                 }
1405         }
1406 
1407         if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1408                 return DIE_FIND_CB_CONTINUE;
1409         else
1410                 return DIE_FIND_CB_SIBLING;
1411 error:
1412         strbuf_release(&buf);
1413         pr_debug("Error in strbuf\n");
1414         return DIE_FIND_CB_END;
1415 }
1416 
1417 /* Add a found vars into available variables list */
1418 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1419 {
1420         struct available_var_finder *af =
1421                         container_of(pf, struct available_var_finder, pf);
1422         struct perf_probe_point *pp = &pf->pev->point;
1423         struct variable_list *vl;
1424         Dwarf_Die die_mem;
1425         int ret;
1426 
1427         /* Check number of tevs */
1428         if (af->nvls == af->max_vls) {
1429                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1430                 return -ERANGE;
1431         }
1432         vl = &af->vls[af->nvls++];
1433 
1434         /* Trace point should be converted from subprogram DIE */
1435         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1436                                      pp->retprobe, pp->function, &vl->point);
1437         if (ret < 0)
1438                 return ret;
1439 
1440         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1441                  vl->point.offset);
1442 
1443         /* Find local variables */
1444         vl->vars = strlist__new(NULL, NULL);
1445         if (vl->vars == NULL)
1446                 return -ENOMEM;
1447         af->child = true;
1448         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1449 
1450         /* Find external variables */
1451         if (!probe_conf.show_ext_vars)
1452                 goto out;
1453         /* Don't need to search child DIE for external vars. */
1454         af->child = false;
1455         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1456 
1457 out:
1458         if (strlist__empty(vl->vars)) {
1459                 strlist__delete(vl->vars);
1460                 vl->vars = NULL;
1461         }
1462 
1463         return ret;
1464 }
1465 
1466 /*
1467  * Find available variables at given probe point
1468  * Return the number of found probe points. Return 0 if there is no
1469  * matched probe point. Return <0 if an error occurs.
1470  */
1471 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1472                                       struct perf_probe_event *pev,
1473                                       struct variable_list **vls)
1474 {
1475         struct available_var_finder af = {
1476                         .pf = {.pev = pev, .callback = add_available_vars},
1477                         .mod = dbg->mod,
1478                         .max_vls = probe_conf.max_probes};
1479         int ret;
1480 
1481         /* Allocate result vls array */
1482         *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1483         if (*vls == NULL)
1484                 return -ENOMEM;
1485 
1486         af.vls = *vls;
1487         af.nvls = 0;
1488 
1489         ret = debuginfo__find_probes(dbg, &af.pf);
1490         if (ret < 0) {
1491                 /* Free vlist for error */
1492                 while (af.nvls--) {
1493                         zfree(&af.vls[af.nvls].point.symbol);
1494                         strlist__delete(af.vls[af.nvls].vars);
1495                 }
1496                 zfree(vls);
1497                 return ret;
1498         }
1499 
1500         return (ret < 0) ? ret : af.nvls;
1501 }
1502 
1503 /* For the kernel module, we need a special code to get a DIE */
1504 int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs,
1505                                 bool adjust_offset)
1506 {
1507         int n, i;
1508         Elf32_Word shndx;
1509         Elf_Scn *scn;
1510         Elf *elf;
1511         GElf_Shdr mem, *shdr;
1512         const char *p;
1513 
1514         elf = dwfl_module_getelf(dbg->mod, &dbg->bias);
1515         if (!elf)
1516                 return -EINVAL;
1517 
1518         /* Get the number of relocations */
1519         n = dwfl_module_relocations(dbg->mod);
1520         if (n < 0)
1521                 return -ENOENT;
1522         /* Search the relocation related .text section */
1523         for (i = 0; i < n; i++) {
1524                 p = dwfl_module_relocation_info(dbg->mod, i, &shndx);
1525                 if (strcmp(p, ".text") == 0) {
1526                         /* OK, get the section header */
1527                         scn = elf_getscn(elf, shndx);
1528                         if (!scn)
1529                                 return -ENOENT;
1530                         shdr = gelf_getshdr(scn, &mem);
1531                         if (!shdr)
1532                                 return -ENOENT;
1533                         *offs = shdr->sh_addr;
1534                         if (adjust_offset)
1535                                 *offs -= shdr->sh_offset;
1536                 }
1537         }
1538         return 0;
1539 }
1540 
1541 /* Reverse search */
1542 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1543                                 struct perf_probe_point *ppt)
1544 {
1545         Dwarf_Die cudie, spdie, indie;
1546         Dwarf_Addr _addr = 0, baseaddr = 0;
1547         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1548         int baseline = 0, lineno = 0, ret = 0;
1549 
1550         /* We always need to relocate the address for aranges */
1551         if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0)
1552                 addr += baseaddr;
1553         /* Find cu die */
1554         if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1555                 pr_warning("Failed to find debug information for address %lx\n",
1556                            addr);
1557                 ret = -EINVAL;
1558                 goto end;
1559         }
1560 
1561         /* Find a corresponding line (filename and lineno) */
1562         cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1563         /* Don't care whether it failed or not */
1564 
1565         /* Find a corresponding function (name, baseline and baseaddr) */
1566         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1567                 /* Get function entry information */
1568                 func = basefunc = dwarf_diename(&spdie);
1569                 if (!func ||
1570                     dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1571                     dwarf_decl_line(&spdie, &baseline) != 0) {
1572                         lineno = 0;
1573                         goto post;
1574                 }
1575 
1576                 fname = dwarf_decl_file(&spdie);
1577                 if (addr == (unsigned long)baseaddr) {
1578                         /* Function entry - Relative line number is 0 */
1579                         lineno = baseline;
1580                         goto post;
1581                 }
1582 
1583                 /* Track down the inline functions step by step */
1584                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1585                                                 &indie)) {
1586                         /* There is an inline function */
1587                         if (dwarf_entrypc(&indie, &_addr) == 0 &&
1588                             _addr == addr) {
1589                                 /*
1590                                  * addr is at an inline function entry.
1591                                  * In this case, lineno should be the call-site
1592                                  * line number. (overwrite lineinfo)
1593                                  */
1594                                 lineno = die_get_call_lineno(&indie);
1595                                 fname = die_get_call_file(&indie);
1596                                 break;
1597                         } else {
1598                                 /*
1599                                  * addr is in an inline function body.
1600                                  * Since lineno points one of the lines
1601                                  * of the inline function, baseline should
1602                                  * be the entry line of the inline function.
1603                                  */
1604                                 tmp = dwarf_diename(&indie);
1605                                 if (!tmp ||
1606                                     dwarf_decl_line(&indie, &baseline) != 0)
1607                                         break;
1608                                 func = tmp;
1609                                 spdie = indie;
1610                         }
1611                 }
1612                 /* Verify the lineno and baseline are in a same file */
1613                 tmp = dwarf_decl_file(&spdie);
1614                 if (!tmp || strcmp(tmp, fname) != 0)
1615                         lineno = 0;
1616         }
1617 
1618 post:
1619         /* Make a relative line number or an offset */
1620         if (lineno)
1621                 ppt->line = lineno - baseline;
1622         else if (basefunc) {
1623                 ppt->offset = addr - (unsigned long)baseaddr;
1624                 func = basefunc;
1625         }
1626 
1627         /* Duplicate strings */
1628         if (func) {
1629                 ppt->function = strdup(func);
1630                 if (ppt->function == NULL) {
1631                         ret = -ENOMEM;
1632                         goto end;
1633                 }
1634         }
1635         if (fname) {
1636                 ppt->file = strdup(fname);
1637                 if (ppt->file == NULL) {
1638                         zfree(&ppt->function);
1639                         ret = -ENOMEM;
1640                         goto end;
1641                 }
1642         }
1643 end:
1644         if (ret == 0 && (fname || func))
1645                 ret = 1;        /* Found a point */
1646         return ret;
1647 }
1648 
1649 /* Add a line and store the src path */
1650 static int line_range_add_line(const char *src, unsigned int lineno,
1651                                struct line_range *lr)
1652 {
1653         /* Copy source path */
1654         if (!lr->path) {
1655                 lr->path = strdup(src);
1656                 if (lr->path == NULL)
1657                         return -ENOMEM;
1658         }
1659         return intlist__add(lr->line_list, lineno);
1660 }
1661 
1662 static int line_range_walk_cb(const char *fname, int lineno,
1663                               Dwarf_Addr addr __maybe_unused,
1664                               void *data)
1665 {
1666         struct line_finder *lf = data;
1667         int err;
1668 
1669         if ((strtailcmp(fname, lf->fname) != 0) ||
1670             (lf->lno_s > lineno || lf->lno_e < lineno))
1671                 return 0;
1672 
1673         err = line_range_add_line(fname, lineno, lf->lr);
1674         if (err < 0 && err != -EEXIST)
1675                 return err;
1676 
1677         return 0;
1678 }
1679 
1680 /* Find line range from its line number */
1681 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1682 {
1683         int ret;
1684 
1685         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1686 
1687         /* Update status */
1688         if (ret >= 0)
1689                 if (!intlist__empty(lf->lr->line_list))
1690                         ret = lf->found = 1;
1691                 else
1692                         ret = 0;        /* Lines are not found */
1693         else {
1694                 zfree(&lf->lr->path);
1695         }
1696         return ret;
1697 }
1698 
1699 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1700 {
1701         int ret = find_line_range_by_line(in_die, data);
1702 
1703         /*
1704          * We have to check all instances of inlined function, because
1705          * some execution paths can be optimized out depends on the
1706          * function argument of instances. However, if an error occurs,
1707          * it should be handled by the caller.
1708          */
1709         return ret < 0 ? ret : 0;
1710 }
1711 
1712 /* Search function definition from function name */
1713 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1714 {
1715         struct dwarf_callback_param *param = data;
1716         struct line_finder *lf = param->data;
1717         struct line_range *lr = lf->lr;
1718 
1719         /* Check declared file */
1720         if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1721                 return DWARF_CB_OK;
1722 
1723         if (die_is_func_def(sp_die) &&
1724             die_match_name(sp_die, lr->function)) {
1725                 lf->fname = dwarf_decl_file(sp_die);
1726                 dwarf_decl_line(sp_die, &lr->offset);
1727                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1728                 lf->lno_s = lr->offset + lr->start;
1729                 if (lf->lno_s < 0)      /* Overflow */
1730                         lf->lno_s = INT_MAX;
1731                 lf->lno_e = lr->offset + lr->end;
1732                 if (lf->lno_e < 0)      /* Overflow */
1733                         lf->lno_e = INT_MAX;
1734                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1735                 lr->start = lf->lno_s;
1736                 lr->end = lf->lno_e;
1737                 if (!die_is_func_instance(sp_die))
1738                         param->retval = die_walk_instances(sp_die,
1739                                                 line_range_inline_cb, lf);
1740                 else
1741                         param->retval = find_line_range_by_line(sp_die, lf);
1742                 return DWARF_CB_ABORT;
1743         }
1744         return DWARF_CB_OK;
1745 }
1746 
1747 static int find_line_range_by_func(struct line_finder *lf)
1748 {
1749         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1750         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1751         return param.retval;
1752 }
1753 
1754 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1755 {
1756         struct line_finder lf = {.lr = lr, .found = 0};
1757         int ret = 0;
1758         Dwarf_Off off = 0, noff;
1759         size_t cuhl;
1760         Dwarf_Die *diep;
1761         const char *comp_dir;
1762 
1763         /* Fastpath: lookup by function name from .debug_pubnames section */
1764         if (lr->function) {
1765                 struct pubname_callback_param pubname_param = {
1766                         .function = lr->function, .file = lr->file,
1767                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1768                 struct dwarf_callback_param line_range_param = {
1769                         .data = (void *)&lf, .retval = 0};
1770 
1771                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1772                                   &pubname_param, 0);
1773                 if (pubname_param.found) {
1774                         line_range_search_cb(&lf.sp_die, &line_range_param);
1775                         if (lf.found)
1776                                 goto found;
1777                 }
1778         }
1779 
1780         /* Loop on CUs (Compilation Unit) */
1781         while (!lf.found && ret >= 0) {
1782                 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1783                                  NULL, NULL, NULL) != 0)
1784                         break;
1785 
1786                 /* Get the DIE(Debugging Information Entry) of this CU */
1787                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1788                 if (!diep)
1789                         continue;
1790 
1791                 /* Check if target file is included. */
1792                 if (lr->file)
1793                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1794                 else
1795                         lf.fname = 0;
1796 
1797                 if (!lr->file || lf.fname) {
1798                         if (lr->function)
1799                                 ret = find_line_range_by_func(&lf);
1800                         else {
1801                                 lf.lno_s = lr->start;
1802                                 lf.lno_e = lr->end;
1803                                 ret = find_line_range_by_line(NULL, &lf);
1804                         }
1805                 }
1806                 off = noff;
1807         }
1808 
1809 found:
1810         /* Store comp_dir */
1811         if (lf.found) {
1812                 comp_dir = cu_get_comp_dir(&lf.cu_die);
1813                 if (comp_dir) {
1814                         lr->comp_dir = strdup(comp_dir);
1815                         if (!lr->comp_dir)
1816                                 ret = -ENOMEM;
1817                 }
1818         }
1819 
1820         pr_debug("path: %s\n", lr->path);
1821         return (ret < 0) ? ret : lf.found;
1822 }
1823 
1824 /*
1825  * Find a src file from a DWARF tag path. Prepend optional source path prefix
1826  * and chop off leading directories that do not exist. Result is passed back as
1827  * a newly allocated path on success.
1828  * Return 0 if file was found and readable, -errno otherwise.
1829  */
1830 int get_real_path(const char *raw_path, const char *comp_dir,
1831                          char **new_path)
1832 {
1833         const char *prefix = symbol_conf.source_prefix;
1834 
1835         if (!prefix) {
1836                 if (raw_path[0] != '/' && comp_dir)
1837                         /* If not an absolute path, try to use comp_dir */
1838                         prefix = comp_dir;
1839                 else {
1840                         if (access(raw_path, R_OK) == 0) {
1841                                 *new_path = strdup(raw_path);
1842                                 return *new_path ? 0 : -ENOMEM;
1843                         } else
1844                                 return -errno;
1845                 }
1846         }
1847 
1848         *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1849         if (!*new_path)
1850                 return -ENOMEM;
1851 
1852         for (;;) {
1853                 sprintf(*new_path, "%s/%s", prefix, raw_path);
1854 
1855                 if (access(*new_path, R_OK) == 0)
1856                         return 0;
1857 
1858                 if (!symbol_conf.source_prefix) {
1859                         /* In case of searching comp_dir, don't retry */
1860                         zfree(new_path);
1861                         return -errno;
1862                 }
1863 
1864                 switch (errno) {
1865                 case ENAMETOOLONG:
1866                 case ENOENT:
1867                 case EROFS:
1868                 case EFAULT:
1869                         raw_path = strchr(++raw_path, '/');
1870                         if (!raw_path) {
1871                                 zfree(new_path);
1872                                 return -ENOENT;
1873                         }
1874                         continue;
1875 
1876                 default:
1877                         zfree(new_path);
1878                         return -errno;
1879                 }
1880         }
1881 }
1882 

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