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

Version: ~ [ linux-5.5-rc6 ] ~ [ linux-5.4.11 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.95 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.164 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.209 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.209 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.81 ] ~ [ 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-2.6.32.71 ] ~ [ 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 <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 <stdlib.h>
 30 #include <string.h>
 31 #include <stdarg.h>
 32 #include <dwarf-regs.h>
 33 
 34 #include <linux/bitops.h>
 35 #include "event.h"
 36 #include "dso.h"
 37 #include "debug.h"
 38 #include "intlist.h"
 39 #include "util.h"
 40 #include "symbol.h"
 41 #include "probe-finder.h"
 42 
 43 /* Kprobe tracer basic type is up to u64 */
 44 #define MAX_BASIC_TYPE_BITS     64
 45 
 46 /* Dwarf FL wrappers */
 47 static char *debuginfo_path;    /* Currently dummy */
 48 
 49 static const Dwfl_Callbacks offline_callbacks = {
 50         .find_debuginfo = dwfl_standard_find_debuginfo,
 51         .debuginfo_path = &debuginfo_path,
 52 
 53         .section_address = dwfl_offline_section_address,
 54 
 55         /* We use this table for core files too.  */
 56         .find_elf = dwfl_build_id_find_elf,
 57 };
 58 
 59 /* Get a Dwarf from offline image */
 60 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
 61                                          const char *path)
 62 {
 63         int fd;
 64 
 65         fd = open(path, O_RDONLY);
 66         if (fd < 0)
 67                 return fd;
 68 
 69         dbg->dwfl = dwfl_begin(&offline_callbacks);
 70         if (!dbg->dwfl)
 71                 goto error;
 72 
 73         dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
 74         if (!dbg->mod)
 75                 goto error;
 76 
 77         dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
 78         if (!dbg->dbg)
 79                 goto error;
 80 
 81         return 0;
 82 error:
 83         if (dbg->dwfl)
 84                 dwfl_end(dbg->dwfl);
 85         else
 86                 close(fd);
 87         memset(dbg, 0, sizeof(*dbg));
 88 
 89         return -ENOENT;
 90 }
 91 
 92 static struct debuginfo *__debuginfo__new(const char *path)
 93 {
 94         struct debuginfo *dbg = zalloc(sizeof(*dbg));
 95         if (!dbg)
 96                 return NULL;
 97 
 98         if (debuginfo__init_offline_dwarf(dbg, path) < 0)
 99                 zfree(&dbg);
100         if (dbg)
101                 pr_debug("Open Debuginfo file: %s\n", path);
102         return dbg;
103 }
104 
105 enum dso_binary_type distro_dwarf_types[] = {
106         DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
107         DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
108         DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
109         DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
110         DSO_BINARY_TYPE__NOT_FOUND,
111 };
112 
113 struct debuginfo *debuginfo__new(const char *path)
114 {
115         enum dso_binary_type *type;
116         char buf[PATH_MAX], nil = '\0';
117         struct dso *dso;
118         struct debuginfo *dinfo = NULL;
119 
120         /* Try to open distro debuginfo files */
121         dso = dso__new(path);
122         if (!dso)
123                 goto out;
124 
125         for (type = distro_dwarf_types;
126              !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
127              type++) {
128                 if (dso__read_binary_type_filename(dso, *type, &nil,
129                                                    buf, PATH_MAX) < 0)
130                         continue;
131                 dinfo = __debuginfo__new(buf);
132         }
133         dso__delete(dso);
134 
135 out:
136         /* if failed to open all distro debuginfo, open given binary */
137         return dinfo ? : __debuginfo__new(path);
138 }
139 
140 void debuginfo__delete(struct debuginfo *dbg)
141 {
142         if (dbg) {
143                 if (dbg->dwfl)
144                         dwfl_end(dbg->dwfl);
145                 free(dbg);
146         }
147 }
148 
149 /*
150  * Probe finder related functions
151  */
152 
153 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
154 {
155         struct probe_trace_arg_ref *ref;
156         ref = zalloc(sizeof(struct probe_trace_arg_ref));
157         if (ref != NULL)
158                 ref->offset = offs;
159         return ref;
160 }
161 
162 /*
163  * Convert a location into trace_arg.
164  * If tvar == NULL, this just checks variable can be converted.
165  * If fentry == true and vr_die is a parameter, do huristic search
166  * for the location fuzzed by function entry mcount.
167  */
168 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
169                                      Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
170                                      struct probe_trace_arg *tvar)
171 {
172         Dwarf_Attribute attr;
173         Dwarf_Addr tmp = 0;
174         Dwarf_Op *op;
175         size_t nops;
176         unsigned int regn;
177         Dwarf_Word offs = 0;
178         bool ref = false;
179         const char *regs;
180         int ret;
181 
182         if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
183                 goto static_var;
184 
185         /* TODO: handle more than 1 exprs */
186         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
187                 return -EINVAL; /* Broken DIE ? */
188         if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
189                 ret = dwarf_entrypc(sp_die, &tmp);
190                 if (ret || addr != tmp ||
191                     dwarf_tag(vr_die) != DW_TAG_formal_parameter ||
192                     dwarf_highpc(sp_die, &tmp))
193                         return -ENOENT;
194                 /*
195                  * This is fuzzed by fentry mcount. We try to find the
196                  * parameter location at the earliest address.
197                  */
198                 for (addr += 1; addr <= tmp; addr++) {
199                         if (dwarf_getlocation_addr(&attr, addr, &op,
200                                                    &nops, 1) > 0)
201                                 goto found;
202                 }
203                 return -ENOENT;
204         }
205 found:
206         if (nops == 0)
207                 /* TODO: Support const_value */
208                 return -ENOENT;
209 
210         if (op->atom == DW_OP_addr) {
211 static_var:
212                 if (!tvar)
213                         return 0;
214                 /* Static variables on memory (not stack), make @varname */
215                 ret = strlen(dwarf_diename(vr_die));
216                 tvar->value = zalloc(ret + 2);
217                 if (tvar->value == NULL)
218                         return -ENOMEM;
219                 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
220                 tvar->ref = alloc_trace_arg_ref((long)offs);
221                 if (tvar->ref == NULL)
222                         return -ENOMEM;
223                 return 0;
224         }
225 
226         /* If this is based on frame buffer, set the offset */
227         if (op->atom == DW_OP_fbreg) {
228                 if (fb_ops == NULL)
229                         return -ENOTSUP;
230                 ref = true;
231                 offs = op->number;
232                 op = &fb_ops[0];
233         }
234 
235         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
236                 regn = op->atom - DW_OP_breg0;
237                 offs += op->number;
238                 ref = true;
239         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
240                 regn = op->atom - DW_OP_reg0;
241         } else if (op->atom == DW_OP_bregx) {
242                 regn = op->number;
243                 offs += op->number2;
244                 ref = true;
245         } else if (op->atom == DW_OP_regx) {
246                 regn = op->number;
247         } else {
248                 pr_debug("DW_OP %x is not supported.\n", op->atom);
249                 return -ENOTSUP;
250         }
251 
252         if (!tvar)
253                 return 0;
254 
255         regs = get_arch_regstr(regn);
256         if (!regs) {
257                 /* This should be a bug in DWARF or this tool */
258                 pr_warning("Mapping for the register number %u "
259                            "missing on this architecture.\n", regn);
260                 return -ERANGE;
261         }
262 
263         tvar->value = strdup(regs);
264         if (tvar->value == NULL)
265                 return -ENOMEM;
266 
267         if (ref) {
268                 tvar->ref = alloc_trace_arg_ref((long)offs);
269                 if (tvar->ref == NULL)
270                         return -ENOMEM;
271         }
272         return 0;
273 }
274 
275 #define BYTES_TO_BITS(nb)       ((nb) * BITS_PER_LONG / sizeof(long))
276 
277 static int convert_variable_type(Dwarf_Die *vr_die,
278                                  struct probe_trace_arg *tvar,
279                                  const char *cast)
280 {
281         struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
282         Dwarf_Die type;
283         char buf[16];
284         char sbuf[STRERR_BUFSIZE];
285         int bsize, boffs, total;
286         int ret;
287 
288         /* TODO: check all types */
289         if (cast && strcmp(cast, "string") != 0) {
290                 /* Non string type is OK */
291                 tvar->type = strdup(cast);
292                 return (tvar->type == NULL) ? -ENOMEM : 0;
293         }
294 
295         bsize = dwarf_bitsize(vr_die);
296         if (bsize > 0) {
297                 /* This is a bitfield */
298                 boffs = dwarf_bitoffset(vr_die);
299                 total = dwarf_bytesize(vr_die);
300                 if (boffs < 0 || total < 0)
301                         return -ENOENT;
302                 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
303                                 BYTES_TO_BITS(total));
304                 goto formatted;
305         }
306 
307         if (die_get_real_type(vr_die, &type) == NULL) {
308                 pr_warning("Failed to get a type information of %s.\n",
309                            dwarf_diename(vr_die));
310                 return -ENOENT;
311         }
312 
313         pr_debug("%s type is %s.\n",
314                  dwarf_diename(vr_die), dwarf_diename(&type));
315 
316         if (cast && strcmp(cast, "string") == 0) {      /* String type */
317                 ret = dwarf_tag(&type);
318                 if (ret != DW_TAG_pointer_type &&
319                     ret != DW_TAG_array_type) {
320                         pr_warning("Failed to cast into string: "
321                                    "%s(%s) is not a pointer nor array.\n",
322                                    dwarf_diename(vr_die), dwarf_diename(&type));
323                         return -EINVAL;
324                 }
325                 if (die_get_real_type(&type, &type) == NULL) {
326                         pr_warning("Failed to get a type"
327                                    " information.\n");
328                         return -ENOENT;
329                 }
330                 if (ret == DW_TAG_pointer_type) {
331                         while (*ref_ptr)
332                                 ref_ptr = &(*ref_ptr)->next;
333                         /* Add new reference with offset +0 */
334                         *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
335                         if (*ref_ptr == NULL) {
336                                 pr_warning("Out of memory error\n");
337                                 return -ENOMEM;
338                         }
339                 }
340                 if (!die_compare_name(&type, "char") &&
341                     !die_compare_name(&type, "unsigned char")) {
342                         pr_warning("Failed to cast into string: "
343                                    "%s is not (unsigned) char *.\n",
344                                    dwarf_diename(vr_die));
345                         return -EINVAL;
346                 }
347                 tvar->type = strdup(cast);
348                 return (tvar->type == NULL) ? -ENOMEM : 0;
349         }
350 
351         ret = dwarf_bytesize(&type);
352         if (ret <= 0)
353                 /* No size ... try to use default type */
354                 return 0;
355         ret = BYTES_TO_BITS(ret);
356 
357         /* Check the bitwidth */
358         if (ret > MAX_BASIC_TYPE_BITS) {
359                 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
360                         dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
361                 ret = MAX_BASIC_TYPE_BITS;
362         }
363         ret = snprintf(buf, 16, "%c%d",
364                        die_is_signed_type(&type) ? 's' : 'u', ret);
365 
366 formatted:
367         if (ret < 0 || ret >= 16) {
368                 if (ret >= 16)
369                         ret = -E2BIG;
370                 pr_warning("Failed to convert variable type: %s\n",
371                            strerror_r(-ret, sbuf, sizeof(sbuf)));
372                 return ret;
373         }
374         tvar->type = strdup(buf);
375         if (tvar->type == NULL)
376                 return -ENOMEM;
377         return 0;
378 }
379 
380 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
381                                     struct perf_probe_arg_field *field,
382                                     struct probe_trace_arg_ref **ref_ptr,
383                                     Dwarf_Die *die_mem)
384 {
385         struct probe_trace_arg_ref *ref = *ref_ptr;
386         Dwarf_Die type;
387         Dwarf_Word offs;
388         int ret, tag;
389 
390         pr_debug("converting %s in %s\n", field->name, varname);
391         if (die_get_real_type(vr_die, &type) == NULL) {
392                 pr_warning("Failed to get the type of %s.\n", varname);
393                 return -ENOENT;
394         }
395         pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
396         tag = dwarf_tag(&type);
397 
398         if (field->name[0] == '[' &&
399             (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
400                 if (field->next)
401                         /* Save original type for next field */
402                         memcpy(die_mem, &type, sizeof(*die_mem));
403                 /* Get the type of this array */
404                 if (die_get_real_type(&type, &type) == NULL) {
405                         pr_warning("Failed to get the type of %s.\n", varname);
406                         return -ENOENT;
407                 }
408                 pr_debug2("Array real type: (%x)\n",
409                          (unsigned)dwarf_dieoffset(&type));
410                 if (tag == DW_TAG_pointer_type) {
411                         ref = zalloc(sizeof(struct probe_trace_arg_ref));
412                         if (ref == NULL)
413                                 return -ENOMEM;
414                         if (*ref_ptr)
415                                 (*ref_ptr)->next = ref;
416                         else
417                                 *ref_ptr = ref;
418                 }
419                 ref->offset += dwarf_bytesize(&type) * field->index;
420                 if (!field->next)
421                         /* Save vr_die for converting types */
422                         memcpy(die_mem, vr_die, sizeof(*die_mem));
423                 goto next;
424         } else if (tag == DW_TAG_pointer_type) {
425                 /* Check the pointer and dereference */
426                 if (!field->ref) {
427                         pr_err("Semantic error: %s must be referred by '->'\n",
428                                field->name);
429                         return -EINVAL;
430                 }
431                 /* Get the type pointed by this pointer */
432                 if (die_get_real_type(&type, &type) == NULL) {
433                         pr_warning("Failed to get the type of %s.\n", varname);
434                         return -ENOENT;
435                 }
436                 /* Verify it is a data structure  */
437                 tag = dwarf_tag(&type);
438                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
439                         pr_warning("%s is not a data structure nor an union.\n",
440                                    varname);
441                         return -EINVAL;
442                 }
443 
444                 ref = zalloc(sizeof(struct probe_trace_arg_ref));
445                 if (ref == NULL)
446                         return -ENOMEM;
447                 if (*ref_ptr)
448                         (*ref_ptr)->next = ref;
449                 else
450                         *ref_ptr = ref;
451         } else {
452                 /* Verify it is a data structure  */
453                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
454                         pr_warning("%s is not a data structure nor an union.\n",
455                                    varname);
456                         return -EINVAL;
457                 }
458                 if (field->name[0] == '[') {
459                         pr_err("Semantic error: %s is not a pointor"
460                                " nor array.\n", varname);
461                         return -EINVAL;
462                 }
463                 if (field->ref) {
464                         pr_err("Semantic error: %s must be referred by '.'\n",
465                                field->name);
466                         return -EINVAL;
467                 }
468                 if (!ref) {
469                         pr_warning("Structure on a register is not "
470                                    "supported yet.\n");
471                         return -ENOTSUP;
472                 }
473         }
474 
475         if (die_find_member(&type, field->name, die_mem) == NULL) {
476                 pr_warning("%s(type:%s) has no member %s.\n", varname,
477                            dwarf_diename(&type), field->name);
478                 return -EINVAL;
479         }
480 
481         /* Get the offset of the field */
482         if (tag == DW_TAG_union_type) {
483                 offs = 0;
484         } else {
485                 ret = die_get_data_member_location(die_mem, &offs);
486                 if (ret < 0) {
487                         pr_warning("Failed to get the offset of %s.\n",
488                                    field->name);
489                         return ret;
490                 }
491         }
492         ref->offset += (long)offs;
493 
494 next:
495         /* Converting next field */
496         if (field->next)
497                 return convert_variable_fields(die_mem, field->name,
498                                         field->next, &ref, die_mem);
499         else
500                 return 0;
501 }
502 
503 /* Show a variables in kprobe event format */
504 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
505 {
506         Dwarf_Die die_mem;
507         int ret;
508 
509         pr_debug("Converting variable %s into trace event.\n",
510                  dwarf_diename(vr_die));
511 
512         ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
513                                         &pf->sp_die, pf->tvar);
514         if (ret == -ENOENT || ret == -EINVAL)
515                 pr_err("Failed to find the location of %s at this address.\n"
516                        " Perhaps, it has been optimized out.\n", pf->pvar->var);
517         else if (ret == -ENOTSUP)
518                 pr_err("Sorry, we don't support this variable location yet.\n");
519         else if (ret == 0 && pf->pvar->field) {
520                 ret = convert_variable_fields(vr_die, pf->pvar->var,
521                                               pf->pvar->field, &pf->tvar->ref,
522                                               &die_mem);
523                 vr_die = &die_mem;
524         }
525         if (ret == 0)
526                 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
527         /* *expr will be cached in libdw. Don't free it. */
528         return ret;
529 }
530 
531 /* Find a variable in a scope DIE */
532 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
533 {
534         Dwarf_Die vr_die;
535         char buf[32], *ptr;
536         int ret = 0;
537 
538         if (!is_c_varname(pf->pvar->var)) {
539                 /* Copy raw parameters */
540                 pf->tvar->value = strdup(pf->pvar->var);
541                 if (pf->tvar->value == NULL)
542                         return -ENOMEM;
543                 if (pf->pvar->type) {
544                         pf->tvar->type = strdup(pf->pvar->type);
545                         if (pf->tvar->type == NULL)
546                                 return -ENOMEM;
547                 }
548                 if (pf->pvar->name) {
549                         pf->tvar->name = strdup(pf->pvar->name);
550                         if (pf->tvar->name == NULL)
551                                 return -ENOMEM;
552                 } else
553                         pf->tvar->name = NULL;
554                 return 0;
555         }
556 
557         if (pf->pvar->name)
558                 pf->tvar->name = strdup(pf->pvar->name);
559         else {
560                 ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
561                 if (ret < 0)
562                         return ret;
563                 ptr = strchr(buf, ':'); /* Change type separator to _ */
564                 if (ptr)
565                         *ptr = '_';
566                 pf->tvar->name = strdup(buf);
567         }
568         if (pf->tvar->name == NULL)
569                 return -ENOMEM;
570 
571         pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
572         /* Search child die for local variables and parameters. */
573         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
574                 /* Search again in global variables */
575                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, 0, &vr_die))
576                         pr_warning("Failed to find '%s' in this function.\n",
577                                    pf->pvar->var);
578                         ret = -ENOENT;
579         }
580         if (ret >= 0)
581                 ret = convert_variable(&vr_die, pf);
582 
583         return ret;
584 }
585 
586 /* Convert subprogram DIE to trace point */
587 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
588                                   Dwarf_Addr paddr, bool retprobe,
589                                   struct probe_trace_point *tp)
590 {
591         Dwarf_Addr eaddr, highaddr;
592         GElf_Sym sym;
593         const char *symbol;
594 
595         /* Verify the address is correct */
596         if (dwarf_entrypc(sp_die, &eaddr) != 0) {
597                 pr_warning("Failed to get entry address of %s\n",
598                            dwarf_diename(sp_die));
599                 return -ENOENT;
600         }
601         if (dwarf_highpc(sp_die, &highaddr) != 0) {
602                 pr_warning("Failed to get end address of %s\n",
603                            dwarf_diename(sp_die));
604                 return -ENOENT;
605         }
606         if (paddr > highaddr) {
607                 pr_warning("Offset specified is greater than size of %s\n",
608                            dwarf_diename(sp_die));
609                 return -EINVAL;
610         }
611 
612         symbol = dwarf_diename(sp_die);
613         if (!symbol) {
614                 /* Try to get the symbol name from symtab */
615                 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
616                 if (!symbol) {
617                         pr_warning("Failed to find symbol at 0x%lx\n",
618                                    (unsigned long)paddr);
619                         return -ENOENT;
620                 }
621                 eaddr = sym.st_value;
622         }
623         tp->offset = (unsigned long)(paddr - eaddr);
624         tp->address = (unsigned long)paddr;
625         tp->symbol = strdup(symbol);
626         if (!tp->symbol)
627                 return -ENOMEM;
628 
629         /* Return probe must be on the head of a subprogram */
630         if (retprobe) {
631                 if (eaddr != paddr) {
632                         pr_warning("Return probe must be on the head of"
633                                    " a real function.\n");
634                         return -EINVAL;
635                 }
636                 tp->retprobe = true;
637         }
638 
639         return 0;
640 }
641 
642 /* Call probe_finder callback with scope DIE */
643 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
644 {
645         Dwarf_Attribute fb_attr;
646         size_t nops;
647         int ret;
648 
649         if (!sc_die) {
650                 pr_err("Caller must pass a scope DIE. Program error.\n");
651                 return -EINVAL;
652         }
653 
654         /* If not a real subprogram, find a real one */
655         if (!die_is_func_def(sc_die)) {
656                 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
657                         pr_warning("Failed to find probe point in any "
658                                    "functions.\n");
659                         return -ENOENT;
660                 }
661         } else
662                 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
663 
664         /* Get the frame base attribute/ops from subprogram */
665         dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
666         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
667         if (ret <= 0 || nops == 0) {
668                 pf->fb_ops = NULL;
669 #if _ELFUTILS_PREREQ(0, 142)
670         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
671                    pf->cfi != NULL) {
672                 Dwarf_Frame *frame;
673                 if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
674                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
675                         pr_warning("Failed to get call frame on 0x%jx\n",
676                                    (uintmax_t)pf->addr);
677                         return -ENOENT;
678                 }
679 #endif
680         }
681 
682         /* Call finder's callback handler */
683         ret = pf->callback(sc_die, pf);
684 
685         /* *pf->fb_ops will be cached in libdw. Don't free it. */
686         pf->fb_ops = NULL;
687 
688         return ret;
689 }
690 
691 struct find_scope_param {
692         const char *function;
693         const char *file;
694         int line;
695         int diff;
696         Dwarf_Die *die_mem;
697         bool found;
698 };
699 
700 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
701 {
702         struct find_scope_param *fsp = data;
703         const char *file;
704         int lno;
705 
706         /* Skip if declared file name does not match */
707         if (fsp->file) {
708                 file = dwarf_decl_file(fn_die);
709                 if (!file || strcmp(fsp->file, file) != 0)
710                         return 0;
711         }
712         /* If the function name is given, that's what user expects */
713         if (fsp->function) {
714                 if (die_compare_name(fn_die, fsp->function)) {
715                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
716                         fsp->found = true;
717                         return 1;
718                 }
719         } else {
720                 /* With the line number, find the nearest declared DIE */
721                 dwarf_decl_line(fn_die, &lno);
722                 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
723                         /* Keep a candidate and continue */
724                         fsp->diff = fsp->line - lno;
725                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
726                         fsp->found = true;
727                 }
728         }
729         return 0;
730 }
731 
732 /* Find an appropriate scope fits to given conditions */
733 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
734 {
735         struct find_scope_param fsp = {
736                 .function = pf->pev->point.function,
737                 .file = pf->fname,
738                 .line = pf->lno,
739                 .diff = INT_MAX,
740                 .die_mem = die_mem,
741                 .found = false,
742         };
743 
744         cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
745 
746         return fsp.found ? die_mem : NULL;
747 }
748 
749 static int probe_point_line_walker(const char *fname, int lineno,
750                                    Dwarf_Addr addr, void *data)
751 {
752         struct probe_finder *pf = data;
753         Dwarf_Die *sc_die, die_mem;
754         int ret;
755 
756         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
757                 return 0;
758 
759         pf->addr = addr;
760         sc_die = find_best_scope(pf, &die_mem);
761         if (!sc_die) {
762                 pr_warning("Failed to find scope of probe point.\n");
763                 return -ENOENT;
764         }
765 
766         ret = call_probe_finder(sc_die, pf);
767 
768         /* Continue if no error, because the line will be in inline function */
769         return ret < 0 ? ret : 0;
770 }
771 
772 /* Find probe point from its line number */
773 static int find_probe_point_by_line(struct probe_finder *pf)
774 {
775         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
776 }
777 
778 /* Find lines which match lazy pattern */
779 static int find_lazy_match_lines(struct intlist *list,
780                                  const char *fname, const char *pat)
781 {
782         FILE *fp;
783         char *line = NULL;
784         size_t line_len;
785         ssize_t len;
786         int count = 0, linenum = 1;
787         char sbuf[STRERR_BUFSIZE];
788 
789         fp = fopen(fname, "r");
790         if (!fp) {
791                 pr_warning("Failed to open %s: %s\n", fname,
792                            strerror_r(errno, sbuf, sizeof(sbuf)));
793                 return -errno;
794         }
795 
796         while ((len = getline(&line, &line_len, fp)) > 0) {
797 
798                 if (line[len - 1] == '\n')
799                         line[len - 1] = '\0';
800 
801                 if (strlazymatch(line, pat)) {
802                         intlist__add(list, linenum);
803                         count++;
804                 }
805                 linenum++;
806         }
807 
808         if (ferror(fp))
809                 count = -errno;
810         free(line);
811         fclose(fp);
812 
813         if (count == 0)
814                 pr_debug("No matched lines found in %s.\n", fname);
815         return count;
816 }
817 
818 static int probe_point_lazy_walker(const char *fname, int lineno,
819                                    Dwarf_Addr addr, void *data)
820 {
821         struct probe_finder *pf = data;
822         Dwarf_Die *sc_die, die_mem;
823         int ret;
824 
825         if (!intlist__has_entry(pf->lcache, lineno) ||
826             strtailcmp(fname, pf->fname) != 0)
827                 return 0;
828 
829         pr_debug("Probe line found: line:%d addr:0x%llx\n",
830                  lineno, (unsigned long long)addr);
831         pf->addr = addr;
832         pf->lno = lineno;
833         sc_die = find_best_scope(pf, &die_mem);
834         if (!sc_die) {
835                 pr_warning("Failed to find scope of probe point.\n");
836                 return -ENOENT;
837         }
838 
839         ret = call_probe_finder(sc_die, pf);
840 
841         /*
842          * Continue if no error, because the lazy pattern will match
843          * to other lines
844          */
845         return ret < 0 ? ret : 0;
846 }
847 
848 /* Find probe points from lazy pattern  */
849 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
850 {
851         int ret = 0;
852 
853         if (intlist__empty(pf->lcache)) {
854                 /* Matching lazy line pattern */
855                 ret = find_lazy_match_lines(pf->lcache, pf->fname,
856                                             pf->pev->point.lazy_line);
857                 if (ret <= 0)
858                         return ret;
859         }
860 
861         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
862 }
863 
864 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
865 {
866         struct probe_finder *pf = data;
867         struct perf_probe_point *pp = &pf->pev->point;
868         Dwarf_Addr addr;
869         int ret;
870 
871         if (pp->lazy_line)
872                 ret = find_probe_point_lazy(in_die, pf);
873         else {
874                 /* Get probe address */
875                 if (dwarf_entrypc(in_die, &addr) != 0) {
876                         pr_warning("Failed to get entry address of %s.\n",
877                                    dwarf_diename(in_die));
878                         return -ENOENT;
879                 }
880                 pf->addr = addr;
881                 pf->addr += pp->offset;
882                 pr_debug("found inline addr: 0x%jx\n",
883                          (uintmax_t)pf->addr);
884 
885                 ret = call_probe_finder(in_die, pf);
886         }
887 
888         return ret;
889 }
890 
891 /* Callback parameter with return value for libdw */
892 struct dwarf_callback_param {
893         void *data;
894         int retval;
895 };
896 
897 /* Search function from function name */
898 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
899 {
900         struct dwarf_callback_param *param = data;
901         struct probe_finder *pf = param->data;
902         struct perf_probe_point *pp = &pf->pev->point;
903 
904         /* Check tag and diename */
905         if (!die_is_func_def(sp_die) ||
906             !die_compare_name(sp_die, pp->function))
907                 return DWARF_CB_OK;
908 
909         /* Check declared file */
910         if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
911                 return DWARF_CB_OK;
912 
913         pf->fname = dwarf_decl_file(sp_die);
914         if (pp->line) { /* Function relative line */
915                 dwarf_decl_line(sp_die, &pf->lno);
916                 pf->lno += pp->line;
917                 param->retval = find_probe_point_by_line(pf);
918         } else if (!dwarf_func_inline(sp_die)) {
919                 /* Real function */
920                 if (pp->lazy_line)
921                         param->retval = find_probe_point_lazy(sp_die, pf);
922                 else {
923                         if (dwarf_entrypc(sp_die, &pf->addr) != 0) {
924                                 pr_warning("Failed to get entry address of "
925                                            "%s.\n", dwarf_diename(sp_die));
926                                 param->retval = -ENOENT;
927                                 return DWARF_CB_ABORT;
928                         }
929                         pf->addr += pp->offset;
930                         /* TODO: Check the address in this function */
931                         param->retval = call_probe_finder(sp_die, pf);
932                 }
933         } else
934                 /* Inlined function: search instances */
935                 param->retval = die_walk_instances(sp_die,
936                                         probe_point_inline_cb, (void *)pf);
937 
938         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
939 }
940 
941 static int find_probe_point_by_func(struct probe_finder *pf)
942 {
943         struct dwarf_callback_param _param = {.data = (void *)pf,
944                                               .retval = 0};
945         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
946         return _param.retval;
947 }
948 
949 struct pubname_callback_param {
950         char *function;
951         char *file;
952         Dwarf_Die *cu_die;
953         Dwarf_Die *sp_die;
954         int found;
955 };
956 
957 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
958 {
959         struct pubname_callback_param *param = data;
960 
961         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
962                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
963                         return DWARF_CB_OK;
964 
965                 if (die_compare_name(param->sp_die, param->function)) {
966                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
967                                 return DWARF_CB_OK;
968 
969                         if (param->file &&
970                             strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
971                                 return DWARF_CB_OK;
972 
973                         param->found = 1;
974                         return DWARF_CB_ABORT;
975                 }
976         }
977 
978         return DWARF_CB_OK;
979 }
980 
981 /* Find probe points from debuginfo */
982 static int debuginfo__find_probes(struct debuginfo *dbg,
983                                   struct probe_finder *pf)
984 {
985         struct perf_probe_point *pp = &pf->pev->point;
986         Dwarf_Off off, noff;
987         size_t cuhl;
988         Dwarf_Die *diep;
989         int ret = 0;
990 
991 #if _ELFUTILS_PREREQ(0, 142)
992         /* Get the call frame information from this dwarf */
993         pf->cfi = dwarf_getcfi_elf(dwarf_getelf(dbg->dbg));
994 #endif
995 
996         off = 0;
997         pf->lcache = intlist__new(NULL);
998         if (!pf->lcache)
999                 return -ENOMEM;
1000 
1001         /* Fastpath: lookup by function name from .debug_pubnames section */
1002         if (pp->function) {
1003                 struct pubname_callback_param pubname_param = {
1004                         .function = pp->function,
1005                         .file     = pp->file,
1006                         .cu_die   = &pf->cu_die,
1007                         .sp_die   = &pf->sp_die,
1008                         .found    = 0,
1009                 };
1010                 struct dwarf_callback_param probe_param = {
1011                         .data = pf,
1012                 };
1013 
1014                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1015                                   &pubname_param, 0);
1016                 if (pubname_param.found) {
1017                         ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1018                         if (ret)
1019                                 goto found;
1020                 }
1021         }
1022 
1023         /* Loop on CUs (Compilation Unit) */
1024         while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1025                 /* Get the DIE(Debugging Information Entry) of this CU */
1026                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1027                 if (!diep)
1028                         continue;
1029 
1030                 /* Check if target file is included. */
1031                 if (pp->file)
1032                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1033                 else
1034                         pf->fname = NULL;
1035 
1036                 if (!pp->file || pf->fname) {
1037                         if (pp->function)
1038                                 ret = find_probe_point_by_func(pf);
1039                         else if (pp->lazy_line)
1040                                 ret = find_probe_point_lazy(NULL, pf);
1041                         else {
1042                                 pf->lno = pp->line;
1043                                 ret = find_probe_point_by_line(pf);
1044                         }
1045                         if (ret < 0)
1046                                 break;
1047                 }
1048                 off = noff;
1049         }
1050 
1051 found:
1052         intlist__delete(pf->lcache);
1053         pf->lcache = NULL;
1054 
1055         return ret;
1056 }
1057 
1058 struct local_vars_finder {
1059         struct probe_finder *pf;
1060         struct perf_probe_arg *args;
1061         int max_args;
1062         int nargs;
1063         int ret;
1064 };
1065 
1066 /* Collect available variables in this scope */
1067 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1068 {
1069         struct local_vars_finder *vf = data;
1070         struct probe_finder *pf = vf->pf;
1071         int tag;
1072 
1073         tag = dwarf_tag(die_mem);
1074         if (tag == DW_TAG_formal_parameter ||
1075             tag == DW_TAG_variable) {
1076                 if (convert_variable_location(die_mem, vf->pf->addr,
1077                                               vf->pf->fb_ops, &pf->sp_die,
1078                                               NULL) == 0) {
1079                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1080                         if (vf->args[vf->nargs].var == NULL) {
1081                                 vf->ret = -ENOMEM;
1082                                 return DIE_FIND_CB_END;
1083                         }
1084                         pr_debug(" %s", vf->args[vf->nargs].var);
1085                         vf->nargs++;
1086                 }
1087         }
1088 
1089         if (dwarf_haspc(die_mem, vf->pf->addr))
1090                 return DIE_FIND_CB_CONTINUE;
1091         else
1092                 return DIE_FIND_CB_SIBLING;
1093 }
1094 
1095 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1096                              struct perf_probe_arg *args)
1097 {
1098         Dwarf_Die die_mem;
1099         int i;
1100         int n = 0;
1101         struct local_vars_finder vf = {.pf = pf, .args = args,
1102                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1103 
1104         for (i = 0; i < pf->pev->nargs; i++) {
1105                 /* var never be NULL */
1106                 if (strcmp(pf->pev->args[i].var, "$vars") == 0) {
1107                         pr_debug("Expanding $vars into:");
1108                         vf.nargs = n;
1109                         /* Special local variables */
1110                         die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1111                                        &die_mem);
1112                         pr_debug(" (%d)\n", vf.nargs - n);
1113                         if (vf.ret < 0)
1114                                 return vf.ret;
1115                         n = vf.nargs;
1116                 } else {
1117                         /* Copy normal argument */
1118                         args[n] = pf->pev->args[i];
1119                         n++;
1120                 }
1121         }
1122         return n;
1123 }
1124 
1125 /* Add a found probe point into trace event list */
1126 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1127 {
1128         struct trace_event_finder *tf =
1129                         container_of(pf, struct trace_event_finder, pf);
1130         struct probe_trace_event *tev;
1131         struct perf_probe_arg *args;
1132         int ret, i;
1133 
1134         /* Check number of tevs */
1135         if (tf->ntevs == tf->max_tevs) {
1136                 pr_warning("Too many( > %d) probe point found.\n",
1137                            tf->max_tevs);
1138                 return -ERANGE;
1139         }
1140         tev = &tf->tevs[tf->ntevs++];
1141 
1142         /* Trace point should be converted from subprogram DIE */
1143         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1144                                      pf->pev->point.retprobe, &tev->point);
1145         if (ret < 0)
1146                 return ret;
1147 
1148         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1149                  tev->point.offset);
1150 
1151         /* Expand special probe argument if exist */
1152         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1153         if (args == NULL)
1154                 return -ENOMEM;
1155 
1156         ret = expand_probe_args(sc_die, pf, args);
1157         if (ret < 0)
1158                 goto end;
1159 
1160         tev->nargs = ret;
1161         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1162         if (tev->args == NULL) {
1163                 ret = -ENOMEM;
1164                 goto end;
1165         }
1166 
1167         /* Find each argument */
1168         for (i = 0; i < tev->nargs; i++) {
1169                 pf->pvar = &args[i];
1170                 pf->tvar = &tev->args[i];
1171                 /* Variable should be found from scope DIE */
1172                 ret = find_variable(sc_die, pf);
1173                 if (ret != 0)
1174                         break;
1175         }
1176 
1177 end:
1178         free(args);
1179         return ret;
1180 }
1181 
1182 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1183 int debuginfo__find_trace_events(struct debuginfo *dbg,
1184                                  struct perf_probe_event *pev,
1185                                  struct probe_trace_event **tevs, int max_tevs)
1186 {
1187         struct trace_event_finder tf = {
1188                         .pf = {.pev = pev, .callback = add_probe_trace_event},
1189                         .mod = dbg->mod, .max_tevs = max_tevs};
1190         int ret;
1191 
1192         /* Allocate result tevs array */
1193         *tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs);
1194         if (*tevs == NULL)
1195                 return -ENOMEM;
1196 
1197         tf.tevs = *tevs;
1198         tf.ntevs = 0;
1199 
1200         ret = debuginfo__find_probes(dbg, &tf.pf);
1201         if (ret < 0) {
1202                 zfree(tevs);
1203                 return ret;
1204         }
1205 
1206         return (ret < 0) ? ret : tf.ntevs;
1207 }
1208 
1209 #define MAX_VAR_LEN 64
1210 
1211 /* Collect available variables in this scope */
1212 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1213 {
1214         struct available_var_finder *af = data;
1215         struct variable_list *vl;
1216         char buf[MAX_VAR_LEN];
1217         int tag, ret;
1218 
1219         vl = &af->vls[af->nvls - 1];
1220 
1221         tag = dwarf_tag(die_mem);
1222         if (tag == DW_TAG_formal_parameter ||
1223             tag == DW_TAG_variable) {
1224                 ret = convert_variable_location(die_mem, af->pf.addr,
1225                                                 af->pf.fb_ops, &af->pf.sp_die,
1226                                                 NULL);
1227                 if (ret == 0) {
1228                         ret = die_get_varname(die_mem, buf, MAX_VAR_LEN);
1229                         pr_debug2("Add new var: %s\n", buf);
1230                         if (ret > 0)
1231                                 strlist__add(vl->vars, buf);
1232                 }
1233         }
1234 
1235         if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1236                 return DIE_FIND_CB_CONTINUE;
1237         else
1238                 return DIE_FIND_CB_SIBLING;
1239 }
1240 
1241 /* Add a found vars into available variables list */
1242 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1243 {
1244         struct available_var_finder *af =
1245                         container_of(pf, struct available_var_finder, pf);
1246         struct variable_list *vl;
1247         Dwarf_Die die_mem;
1248         int ret;
1249 
1250         /* Check number of tevs */
1251         if (af->nvls == af->max_vls) {
1252                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1253                 return -ERANGE;
1254         }
1255         vl = &af->vls[af->nvls++];
1256 
1257         /* Trace point should be converted from subprogram DIE */
1258         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1259                                      pf->pev->point.retprobe, &vl->point);
1260         if (ret < 0)
1261                 return ret;
1262 
1263         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1264                  vl->point.offset);
1265 
1266         /* Find local variables */
1267         vl->vars = strlist__new(true, NULL);
1268         if (vl->vars == NULL)
1269                 return -ENOMEM;
1270         af->child = true;
1271         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1272 
1273         /* Find external variables */
1274         if (!af->externs)
1275                 goto out;
1276         /* Don't need to search child DIE for externs. */
1277         af->child = false;
1278         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1279 
1280 out:
1281         if (strlist__empty(vl->vars)) {
1282                 strlist__delete(vl->vars);
1283                 vl->vars = NULL;
1284         }
1285 
1286         return ret;
1287 }
1288 
1289 /*
1290  * Find available variables at given probe point
1291  * Return the number of found probe points. Return 0 if there is no
1292  * matched probe point. Return <0 if an error occurs.
1293  */
1294 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1295                                       struct perf_probe_event *pev,
1296                                       struct variable_list **vls,
1297                                       int max_vls, bool externs)
1298 {
1299         struct available_var_finder af = {
1300                         .pf = {.pev = pev, .callback = add_available_vars},
1301                         .mod = dbg->mod,
1302                         .max_vls = max_vls, .externs = externs};
1303         int ret;
1304 
1305         /* Allocate result vls array */
1306         *vls = zalloc(sizeof(struct variable_list) * max_vls);
1307         if (*vls == NULL)
1308                 return -ENOMEM;
1309 
1310         af.vls = *vls;
1311         af.nvls = 0;
1312 
1313         ret = debuginfo__find_probes(dbg, &af.pf);
1314         if (ret < 0) {
1315                 /* Free vlist for error */
1316                 while (af.nvls--) {
1317                         zfree(&af.vls[af.nvls].point.symbol);
1318                         strlist__delete(af.vls[af.nvls].vars);
1319                 }
1320                 zfree(vls);
1321                 return ret;
1322         }
1323 
1324         return (ret < 0) ? ret : af.nvls;
1325 }
1326 
1327 /* Reverse search */
1328 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1329                                 struct perf_probe_point *ppt)
1330 {
1331         Dwarf_Die cudie, spdie, indie;
1332         Dwarf_Addr _addr = 0, baseaddr = 0;
1333         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1334         int baseline = 0, lineno = 0, ret = 0;
1335 
1336         /* Adjust address with bias */
1337         addr += dbg->bias;
1338 
1339         /* Find cu die */
1340         if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr - dbg->bias, &cudie)) {
1341                 pr_warning("Failed to find debug information for address %lx\n",
1342                            addr);
1343                 ret = -EINVAL;
1344                 goto end;
1345         }
1346 
1347         /* Find a corresponding line (filename and lineno) */
1348         cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1349         /* Don't care whether it failed or not */
1350 
1351         /* Find a corresponding function (name, baseline and baseaddr) */
1352         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1353                 /* Get function entry information */
1354                 func = basefunc = dwarf_diename(&spdie);
1355                 if (!func ||
1356                     dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1357                     dwarf_decl_line(&spdie, &baseline) != 0) {
1358                         lineno = 0;
1359                         goto post;
1360                 }
1361 
1362                 fname = dwarf_decl_file(&spdie);
1363                 if (addr == (unsigned long)baseaddr) {
1364                         /* Function entry - Relative line number is 0 */
1365                         lineno = baseline;
1366                         goto post;
1367                 }
1368 
1369                 /* Track down the inline functions step by step */
1370                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1371                                                 &indie)) {
1372                         /* There is an inline function */
1373                         if (dwarf_entrypc(&indie, &_addr) == 0 &&
1374                             _addr == addr) {
1375                                 /*
1376                                  * addr is at an inline function entry.
1377                                  * In this case, lineno should be the call-site
1378                                  * line number. (overwrite lineinfo)
1379                                  */
1380                                 lineno = die_get_call_lineno(&indie);
1381                                 fname = die_get_call_file(&indie);
1382                                 break;
1383                         } else {
1384                                 /*
1385                                  * addr is in an inline function body.
1386                                  * Since lineno points one of the lines
1387                                  * of the inline function, baseline should
1388                                  * be the entry line of the inline function.
1389                                  */
1390                                 tmp = dwarf_diename(&indie);
1391                                 if (!tmp ||
1392                                     dwarf_decl_line(&indie, &baseline) != 0)
1393                                         break;
1394                                 func = tmp;
1395                                 spdie = indie;
1396                         }
1397                 }
1398                 /* Verify the lineno and baseline are in a same file */
1399                 tmp = dwarf_decl_file(&spdie);
1400                 if (!tmp || strcmp(tmp, fname) != 0)
1401                         lineno = 0;
1402         }
1403 
1404 post:
1405         /* Make a relative line number or an offset */
1406         if (lineno)
1407                 ppt->line = lineno - baseline;
1408         else if (basefunc) {
1409                 ppt->offset = addr - (unsigned long)baseaddr;
1410                 func = basefunc;
1411         }
1412 
1413         /* Duplicate strings */
1414         if (func) {
1415                 ppt->function = strdup(func);
1416                 if (ppt->function == NULL) {
1417                         ret = -ENOMEM;
1418                         goto end;
1419                 }
1420         }
1421         if (fname) {
1422                 ppt->file = strdup(fname);
1423                 if (ppt->file == NULL) {
1424                         zfree(&ppt->function);
1425                         ret = -ENOMEM;
1426                         goto end;
1427                 }
1428         }
1429 end:
1430         if (ret == 0 && (fname || func))
1431                 ret = 1;        /* Found a point */
1432         return ret;
1433 }
1434 
1435 /* Add a line and store the src path */
1436 static int line_range_add_line(const char *src, unsigned int lineno,
1437                                struct line_range *lr)
1438 {
1439         /* Copy source path */
1440         if (!lr->path) {
1441                 lr->path = strdup(src);
1442                 if (lr->path == NULL)
1443                         return -ENOMEM;
1444         }
1445         return intlist__add(lr->line_list, lineno);
1446 }
1447 
1448 static int line_range_walk_cb(const char *fname, int lineno,
1449                               Dwarf_Addr addr __maybe_unused,
1450                               void *data)
1451 {
1452         struct line_finder *lf = data;
1453         int err;
1454 
1455         if ((strtailcmp(fname, lf->fname) != 0) ||
1456             (lf->lno_s > lineno || lf->lno_e < lineno))
1457                 return 0;
1458 
1459         err = line_range_add_line(fname, lineno, lf->lr);
1460         if (err < 0 && err != -EEXIST)
1461                 return err;
1462 
1463         return 0;
1464 }
1465 
1466 /* Find line range from its line number */
1467 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1468 {
1469         int ret;
1470 
1471         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1472 
1473         /* Update status */
1474         if (ret >= 0)
1475                 if (!intlist__empty(lf->lr->line_list))
1476                         ret = lf->found = 1;
1477                 else
1478                         ret = 0;        /* Lines are not found */
1479         else {
1480                 zfree(&lf->lr->path);
1481         }
1482         return ret;
1483 }
1484 
1485 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1486 {
1487         int ret = find_line_range_by_line(in_die, data);
1488 
1489         /*
1490          * We have to check all instances of inlined function, because
1491          * some execution paths can be optimized out depends on the
1492          * function argument of instances. However, if an error occurs,
1493          * it should be handled by the caller.
1494          */
1495         return ret < 0 ? ret : 0;
1496 }
1497 
1498 /* Search function definition from function name */
1499 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1500 {
1501         struct dwarf_callback_param *param = data;
1502         struct line_finder *lf = param->data;
1503         struct line_range *lr = lf->lr;
1504 
1505         /* Check declared file */
1506         if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1507                 return DWARF_CB_OK;
1508 
1509         if (die_is_func_def(sp_die) &&
1510             die_compare_name(sp_die, lr->function)) {
1511                 lf->fname = dwarf_decl_file(sp_die);
1512                 dwarf_decl_line(sp_die, &lr->offset);
1513                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1514                 lf->lno_s = lr->offset + lr->start;
1515                 if (lf->lno_s < 0)      /* Overflow */
1516                         lf->lno_s = INT_MAX;
1517                 lf->lno_e = lr->offset + lr->end;
1518                 if (lf->lno_e < 0)      /* Overflow */
1519                         lf->lno_e = INT_MAX;
1520                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1521                 lr->start = lf->lno_s;
1522                 lr->end = lf->lno_e;
1523                 if (dwarf_func_inline(sp_die))
1524                         param->retval = die_walk_instances(sp_die,
1525                                                 line_range_inline_cb, lf);
1526                 else
1527                         param->retval = find_line_range_by_line(sp_die, lf);
1528                 return DWARF_CB_ABORT;
1529         }
1530         return DWARF_CB_OK;
1531 }
1532 
1533 static int find_line_range_by_func(struct line_finder *lf)
1534 {
1535         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1536         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1537         return param.retval;
1538 }
1539 
1540 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1541 {
1542         struct line_finder lf = {.lr = lr, .found = 0};
1543         int ret = 0;
1544         Dwarf_Off off = 0, noff;
1545         size_t cuhl;
1546         Dwarf_Die *diep;
1547         const char *comp_dir;
1548 
1549         /* Fastpath: lookup by function name from .debug_pubnames section */
1550         if (lr->function) {
1551                 struct pubname_callback_param pubname_param = {
1552                         .function = lr->function, .file = lr->file,
1553                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1554                 struct dwarf_callback_param line_range_param = {
1555                         .data = (void *)&lf, .retval = 0};
1556 
1557                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1558                                   &pubname_param, 0);
1559                 if (pubname_param.found) {
1560                         line_range_search_cb(&lf.sp_die, &line_range_param);
1561                         if (lf.found)
1562                                 goto found;
1563                 }
1564         }
1565 
1566         /* Loop on CUs (Compilation Unit) */
1567         while (!lf.found && ret >= 0) {
1568                 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1569                                  NULL, NULL, NULL) != 0)
1570                         break;
1571 
1572                 /* Get the DIE(Debugging Information Entry) of this CU */
1573                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1574                 if (!diep)
1575                         continue;
1576 
1577                 /* Check if target file is included. */
1578                 if (lr->file)
1579                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1580                 else
1581                         lf.fname = 0;
1582 
1583                 if (!lr->file || lf.fname) {
1584                         if (lr->function)
1585                                 ret = find_line_range_by_func(&lf);
1586                         else {
1587                                 lf.lno_s = lr->start;
1588                                 lf.lno_e = lr->end;
1589                                 ret = find_line_range_by_line(NULL, &lf);
1590                         }
1591                 }
1592                 off = noff;
1593         }
1594 
1595 found:
1596         /* Store comp_dir */
1597         if (lf.found) {
1598                 comp_dir = cu_get_comp_dir(&lf.cu_die);
1599                 if (comp_dir) {
1600                         lr->comp_dir = strdup(comp_dir);
1601                         if (!lr->comp_dir)
1602                                 ret = -ENOMEM;
1603                 }
1604         }
1605 
1606         pr_debug("path: %s\n", lr->path);
1607         return (ret < 0) ? ret : lf.found;
1608 }
1609 
1610 

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