Root/tools/perf/util/probe-finder.c

1/*
2 * probe-finder.c : C expression to kprobe event converter
3 *
4 * Written by Masami Hiramatsu <mhiramat@redhat.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
19 *
20 */
21
22#include <sys/utsname.h>
23#include <sys/types.h>
24#include <sys/stat.h>
25#include <fcntl.h>
26#include <errno.h>
27#include <stdio.h>
28#include <unistd.h>
29#include <getopt.h>
30#include <stdlib.h>
31#include <string.h>
32#include <stdarg.h>
33#include <ctype.h>
34
35#include "string.h"
36#include "event.h"
37#include "debug.h"
38#include "util.h"
39#include "probe-finder.h"
40
41
42/*
43 * Generic dwarf analysis helpers
44 */
45
46#define X86_32_MAX_REGS 8
47const char *x86_32_regs_table[X86_32_MAX_REGS] = {
48    "%ax",
49    "%cx",
50    "%dx",
51    "%bx",
52    "$stack", /* Stack address instead of %sp */
53    "%bp",
54    "%si",
55    "%di",
56};
57
58#define X86_64_MAX_REGS 16
59const char *x86_64_regs_table[X86_64_MAX_REGS] = {
60    "%ax",
61    "%dx",
62    "%cx",
63    "%bx",
64    "%si",
65    "%di",
66    "%bp",
67    "%sp",
68    "%r8",
69    "%r9",
70    "%r10",
71    "%r11",
72    "%r12",
73    "%r13",
74    "%r14",
75    "%r15",
76};
77
78/* TODO: switching by dwarf address size */
79#ifdef __x86_64__
80#define ARCH_MAX_REGS X86_64_MAX_REGS
81#define arch_regs_table x86_64_regs_table
82#else
83#define ARCH_MAX_REGS X86_32_MAX_REGS
84#define arch_regs_table x86_32_regs_table
85#endif
86
87/* Return architecture dependent register string (for kprobe-tracer) */
88static const char *get_arch_regstr(unsigned int n)
89{
90    return (n <= ARCH_MAX_REGS) ? arch_regs_table[n] : NULL;
91}
92
93/*
94 * Compare the tail of two strings.
95 * Return 0 if whole of either string is same as another's tail part.
96 */
97static int strtailcmp(const char *s1, const char *s2)
98{
99    int i1 = strlen(s1);
100    int i2 = strlen(s2);
101    while (--i1 >= 0 && --i2 >= 0) {
102        if (s1[i1] != s2[i2])
103            return s1[i1] - s2[i2];
104    }
105    return 0;
106}
107
108/* Line number list operations */
109
110/* Add a line to line number list */
111static void line_list__add_line(struct list_head *head, unsigned int line)
112{
113    struct line_node *ln;
114    struct list_head *p;
115
116    /* Reverse search, because new line will be the last one */
117    list_for_each_entry_reverse(ln, head, list) {
118        if (ln->line < line) {
119            p = &ln->list;
120            goto found;
121        } else if (ln->line == line) /* Already exist */
122            return ;
123    }
124    /* List is empty, or the smallest entry */
125    p = head;
126found:
127    pr_debug("line list: add a line %u\n", line);
128    ln = zalloc(sizeof(struct line_node));
129    DIE_IF(ln == NULL);
130    ln->line = line;
131    INIT_LIST_HEAD(&ln->list);
132    list_add(&ln->list, p);
133}
134
135/* Check if the line in line number list */
136static int line_list__has_line(struct list_head *head, unsigned int line)
137{
138    struct line_node *ln;
139
140    /* Reverse search, because new line will be the last one */
141    list_for_each_entry(ln, head, list)
142        if (ln->line == line)
143            return 1;
144
145    return 0;
146}
147
148/* Init line number list */
149static void line_list__init(struct list_head *head)
150{
151    INIT_LIST_HEAD(head);
152}
153
154/* Free line number list */
155static void line_list__free(struct list_head *head)
156{
157    struct line_node *ln;
158    while (!list_empty(head)) {
159        ln = list_first_entry(head, struct line_node, list);
160        list_del(&ln->list);
161        free(ln);
162    }
163}
164
165/* Dwarf wrappers */
166
167/* Find the realpath of the target file. */
168static const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname)
169{
170    Dwarf_Files *files;
171    size_t nfiles, i;
172    const char *src = NULL;
173    int ret;
174
175    if (!fname)
176        return NULL;
177
178    ret = dwarf_getsrcfiles(cu_die, &files, &nfiles);
179    if (ret != 0)
180        return NULL;
181
182    for (i = 0; i < nfiles; i++) {
183        src = dwarf_filesrc(files, i, NULL, NULL);
184        if (strtailcmp(src, fname) == 0)
185            break;
186    }
187    return src;
188}
189
190struct __addr_die_search_param {
191    Dwarf_Addr addr;
192    Dwarf_Die *die_mem;
193};
194
195static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
196{
197    struct __addr_die_search_param *ad = data;
198
199    if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
200        dwarf_haspc(fn_die, ad->addr)) {
201        memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
202        return DWARF_CB_ABORT;
203    }
204    return DWARF_CB_OK;
205}
206
207/* Search a real subprogram including this line, */
208static Dwarf_Die *die_get_real_subprogram(Dwarf_Die *cu_die, Dwarf_Addr addr,
209                      Dwarf_Die *die_mem)
210{
211    struct __addr_die_search_param ad;
212    ad.addr = addr;
213    ad.die_mem = die_mem;
214    /* dwarf_getscopes can't find subprogram. */
215    if (!dwarf_getfuncs(cu_die, __die_search_func_cb, &ad, 0))
216        return NULL;
217    else
218        return die_mem;
219}
220
221/* Similar to dwarf_getfuncs, but returns inlined_subroutine if exists. */
222static Dwarf_Die *die_get_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
223                     Dwarf_Die *die_mem)
224{
225    Dwarf_Die child_die;
226    int ret;
227
228    ret = dwarf_child(sp_die, die_mem);
229    if (ret != 0)
230        return NULL;
231
232    do {
233        if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
234            dwarf_haspc(die_mem, addr))
235            return die_mem;
236
237        if (die_get_inlinefunc(die_mem, addr, &child_die)) {
238            memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
239            return die_mem;
240        }
241    } while (dwarf_siblingof(die_mem, die_mem) == 0);
242
243    return NULL;
244}
245
246/* Compare diename and tname */
247static bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
248{
249    const char *name;
250    name = dwarf_diename(dw_die);
251    DIE_IF(name == NULL);
252    return strcmp(tname, name);
253}
254
255/* Get entry pc(or low pc, 1st entry of ranges) of the die */
256static Dwarf_Addr die_get_entrypc(Dwarf_Die *dw_die)
257{
258    Dwarf_Addr epc;
259    int ret;
260
261    ret = dwarf_entrypc(dw_die, &epc);
262    DIE_IF(ret == -1);
263    return epc;
264}
265
266/* Get a variable die */
267static Dwarf_Die *die_find_variable(Dwarf_Die *sp_die, const char *name,
268                    Dwarf_Die *die_mem)
269{
270    Dwarf_Die child_die;
271    int tag;
272    int ret;
273
274    ret = dwarf_child(sp_die, die_mem);
275    if (ret != 0)
276        return NULL;
277
278    do {
279        tag = dwarf_tag(die_mem);
280        if ((tag == DW_TAG_formal_parameter ||
281             tag == DW_TAG_variable) &&
282            (die_compare_name(die_mem, name) == 0))
283            return die_mem;
284
285        if (die_find_variable(die_mem, name, &child_die)) {
286            memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
287            return die_mem;
288        }
289    } while (dwarf_siblingof(die_mem, die_mem) == 0);
290
291    return NULL;
292}
293
294/*
295 * Probe finder related functions
296 */
297
298/* Show a location */
299static void show_location(Dwarf_Op *op, struct probe_finder *pf)
300{
301    unsigned int regn;
302    Dwarf_Word offs = 0;
303    int deref = 0, ret;
304    const char *regs;
305
306    /* TODO: support CFA */
307    /* If this is based on frame buffer, set the offset */
308    if (op->atom == DW_OP_fbreg) {
309        if (pf->fb_ops == NULL)
310            die("The attribute of frame base is not supported.\n");
311        deref = 1;
312        offs = op->number;
313        op = &pf->fb_ops[0];
314    }
315
316    if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
317        regn = op->atom - DW_OP_breg0;
318        offs += op->number;
319        deref = 1;
320    } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
321        regn = op->atom - DW_OP_reg0;
322    } else if (op->atom == DW_OP_bregx) {
323        regn = op->number;
324        offs += op->number2;
325        deref = 1;
326    } else if (op->atom == DW_OP_regx) {
327        regn = op->number;
328    } else
329        die("DW_OP %d is not supported.", op->atom);
330
331    regs = get_arch_regstr(regn);
332    if (!regs)
333        die("%u exceeds max register number.", regn);
334
335    if (deref)
336        ret = snprintf(pf->buf, pf->len, " %s=%+jd(%s)",
337                   pf->var, (intmax_t)offs, regs);
338    else
339        ret = snprintf(pf->buf, pf->len, " %s=%s", pf->var, regs);
340    DIE_IF(ret < 0);
341    DIE_IF(ret >= pf->len);
342}
343
344/* Show a variables in kprobe event format */
345static void show_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
346{
347    Dwarf_Attribute attr;
348    Dwarf_Op *expr;
349    size_t nexpr;
350    int ret;
351
352    if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
353        goto error;
354    /* TODO: handle more than 1 exprs */
355    ret = dwarf_getlocation_addr(&attr, pf->addr, &expr, &nexpr, 1);
356    if (ret <= 0 || nexpr == 0)
357        goto error;
358
359    show_location(expr, pf);
360    /* *expr will be cached in libdw. Don't free it. */
361    return ;
362error:
363    /* TODO: Support const_value */
364    die("Failed to find the location of %s at this address.\n"
365        " Perhaps, it has been optimized out.", pf->var);
366}
367
368/* Find a variable in a subprogram die */
369static void find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
370{
371    int ret;
372    Dwarf_Die vr_die;
373
374    /* TODO: Support struct members and arrays */
375    if (!is_c_varname(pf->var)) {
376        /* Output raw parameters */
377        ret = snprintf(pf->buf, pf->len, " %s", pf->var);
378        DIE_IF(ret < 0);
379        DIE_IF(ret >= pf->len);
380        return ;
381    }
382
383    pr_debug("Searching '%s' variable in context.\n", pf->var);
384    /* Search child die for local variables and parameters. */
385    if (!die_find_variable(sp_die, pf->var, &vr_die))
386        die("Failed to find '%s' in this function.", pf->var);
387
388    show_variable(&vr_die, pf);
389}
390
391/* Show a probe point to output buffer */
392static void show_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
393{
394    struct probe_point *pp = pf->pp;
395    Dwarf_Addr eaddr;
396    Dwarf_Die die_mem;
397    const char *name;
398    char tmp[MAX_PROBE_BUFFER];
399    int ret, i, len;
400    Dwarf_Attribute fb_attr;
401    size_t nops;
402
403    /* If no real subprogram, find a real one */
404    if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) {
405        sp_die = die_get_real_subprogram(&pf->cu_die,
406                         pf->addr, &die_mem);
407        if (!sp_die)
408            die("Probe point is not found in subprograms.");
409    }
410
411    /* Output name of probe point */
412    name = dwarf_diename(sp_die);
413    if (name) {
414        dwarf_entrypc(sp_die, &eaddr);
415        ret = snprintf(tmp, MAX_PROBE_BUFFER, "%s+%lu", name,
416                (unsigned long)(pf->addr - eaddr));
417        /* Copy the function name if possible */
418        if (!pp->function) {
419            pp->function = strdup(name);
420            pp->offset = (size_t)(pf->addr - eaddr);
421        }
422    } else {
423        /* This function has no name. */
424        ret = snprintf(tmp, MAX_PROBE_BUFFER, "0x%jx",
425                   (uintmax_t)pf->addr);
426        if (!pp->function) {
427            /* TODO: Use _stext */
428            pp->function = strdup("");
429            pp->offset = (size_t)pf->addr;
430        }
431    }
432    DIE_IF(ret < 0);
433    DIE_IF(ret >= MAX_PROBE_BUFFER);
434    len = ret;
435    pr_debug("Probe point found: %s\n", tmp);
436
437    /* Get the frame base attribute/ops */
438    dwarf_attr(sp_die, DW_AT_frame_base, &fb_attr);
439    ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
440    if (ret <= 0 || nops == 0)
441        pf->fb_ops = NULL;
442
443    /* Find each argument */
444    /* TODO: use dwarf_cfi_addrframe */
445    for (i = 0; i < pp->nr_args; i++) {
446        pf->var = pp->args[i];
447        pf->buf = &tmp[len];
448        pf->len = MAX_PROBE_BUFFER - len;
449        find_variable(sp_die, pf);
450        len += strlen(pf->buf);
451    }
452
453    /* *pf->fb_ops will be cached in libdw. Don't free it. */
454    pf->fb_ops = NULL;
455
456    if (pp->found == MAX_PROBES)
457        die("Too many( > %d) probe point found.\n", MAX_PROBES);
458
459    pp->probes[pp->found] = strdup(tmp);
460    pp->found++;
461}
462
463/* Find probe point from its line number */
464static void find_probe_point_by_line(struct probe_finder *pf)
465{
466    Dwarf_Lines *lines;
467    Dwarf_Line *line;
468    size_t nlines, i;
469    Dwarf_Addr addr;
470    int lineno;
471    int ret;
472
473    ret = dwarf_getsrclines(&pf->cu_die, &lines, &nlines);
474    DIE_IF(ret != 0);
475
476    for (i = 0; i < nlines; i++) {
477        line = dwarf_onesrcline(lines, i);
478        dwarf_lineno(line, &lineno);
479        if (lineno != pf->lno)
480            continue;
481
482        /* TODO: Get fileno from line, but how? */
483        if (strtailcmp(dwarf_linesrc(line, NULL, NULL), pf->fname) != 0)
484            continue;
485
486        ret = dwarf_lineaddr(line, &addr);
487        DIE_IF(ret != 0);
488        pr_debug("Probe line found: line[%d]:%d addr:0x%jx\n",
489             (int)i, lineno, (uintmax_t)addr);
490        pf->addr = addr;
491
492        show_probe_point(NULL, pf);
493        /* Continuing, because target line might be inlined. */
494    }
495}
496
497/* Find lines which match lazy pattern */
498static int find_lazy_match_lines(struct list_head *head,
499                 const char *fname, const char *pat)
500{
501    char *fbuf, *p1, *p2;
502    int fd, line, nlines = 0;
503    struct stat st;
504
505    fd = open(fname, O_RDONLY);
506    if (fd < 0)
507        die("failed to open %s", fname);
508    DIE_IF(fstat(fd, &st) < 0);
509    fbuf = malloc(st.st_size + 2);
510    DIE_IF(fbuf == NULL);
511    DIE_IF(read(fd, fbuf, st.st_size) < 0);
512    close(fd);
513    fbuf[st.st_size] = '\n'; /* Dummy line */
514    fbuf[st.st_size + 1] = '\0';
515    p1 = fbuf;
516    line = 1;
517    while ((p2 = strchr(p1, '\n')) != NULL) {
518        *p2 = '\0';
519        if (strlazymatch(p1, pat)) {
520            line_list__add_line(head, line);
521            nlines++;
522        }
523        line++;
524        p1 = p2 + 1;
525    }
526    free(fbuf);
527    return nlines;
528}
529
530/* Find probe points from lazy pattern */
531static void find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
532{
533    Dwarf_Lines *lines;
534    Dwarf_Line *line;
535    size_t nlines, i;
536    Dwarf_Addr addr;
537    Dwarf_Die die_mem;
538    int lineno;
539    int ret;
540
541    if (list_empty(&pf->lcache)) {
542        /* Matching lazy line pattern */
543        ret = find_lazy_match_lines(&pf->lcache, pf->fname,
544                        pf->pp->lazy_line);
545        if (ret <= 0)
546            die("No matched lines found in %s.", pf->fname);
547    }
548
549    ret = dwarf_getsrclines(&pf->cu_die, &lines, &nlines);
550    DIE_IF(ret != 0);
551    for (i = 0; i < nlines; i++) {
552        line = dwarf_onesrcline(lines, i);
553
554        dwarf_lineno(line, &lineno);
555        if (!line_list__has_line(&pf->lcache, lineno))
556            continue;
557
558        /* TODO: Get fileno from line, but how? */
559        if (strtailcmp(dwarf_linesrc(line, NULL, NULL), pf->fname) != 0)
560            continue;
561
562        ret = dwarf_lineaddr(line, &addr);
563        DIE_IF(ret != 0);
564        if (sp_die) {
565            /* Address filtering 1: does sp_die include addr? */
566            if (!dwarf_haspc(sp_die, addr))
567                continue;
568            /* Address filtering 2: No child include addr? */
569            if (die_get_inlinefunc(sp_die, addr, &die_mem))
570                continue;
571        }
572
573        pr_debug("Probe line found: line[%d]:%d addr:0x%llx\n",
574             (int)i, lineno, (unsigned long long)addr);
575        pf->addr = addr;
576
577        show_probe_point(sp_die, pf);
578        /* Continuing, because target line might be inlined. */
579    }
580    /* TODO: deallocate lines, but how? */
581}
582
583static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
584{
585    struct probe_finder *pf = (struct probe_finder *)data;
586    struct probe_point *pp = pf->pp;
587
588    if (pp->lazy_line)
589        find_probe_point_lazy(in_die, pf);
590    else {
591        /* Get probe address */
592        pf->addr = die_get_entrypc(in_die);
593        pf->addr += pp->offset;
594        pr_debug("found inline addr: 0x%jx\n",
595             (uintmax_t)pf->addr);
596
597        show_probe_point(in_die, pf);
598    }
599
600    return DWARF_CB_OK;
601}
602
603/* Search function from function name */
604static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
605{
606    struct probe_finder *pf = (struct probe_finder *)data;
607    struct probe_point *pp = pf->pp;
608
609    /* Check tag and diename */
610    if (dwarf_tag(sp_die) != DW_TAG_subprogram ||
611        die_compare_name(sp_die, pp->function) != 0)
612        return 0;
613
614    pf->fname = dwarf_decl_file(sp_die);
615    if (pp->line) { /* Function relative line */
616        dwarf_decl_line(sp_die, &pf->lno);
617        pf->lno += pp->line;
618        find_probe_point_by_line(pf);
619    } else if (!dwarf_func_inline(sp_die)) {
620        /* Real function */
621        if (pp->lazy_line)
622            find_probe_point_lazy(sp_die, pf);
623        else {
624            pf->addr = die_get_entrypc(sp_die);
625            pf->addr += pp->offset;
626            /* TODO: Check the address in this function */
627            show_probe_point(sp_die, pf);
628        }
629    } else
630        /* Inlined function: search instances */
631        dwarf_func_inline_instances(sp_die, probe_point_inline_cb, pf);
632
633    return 1; /* Exit; no same symbol in this CU. */
634}
635
636static void find_probe_point_by_func(struct probe_finder *pf)
637{
638    dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, pf, 0);
639}
640
641/* Find a probe point */
642int find_probe_point(int fd, struct probe_point *pp)
643{
644    struct probe_finder pf = {.pp = pp};
645    Dwarf_Off off, noff;
646    size_t cuhl;
647    Dwarf_Die *diep;
648    Dwarf *dbg;
649
650    dbg = dwarf_begin(fd, DWARF_C_READ);
651    if (!dbg)
652        return -ENOENT;
653
654    pp->found = 0;
655    off = 0;
656    line_list__init(&pf.lcache);
657    /* Loop on CUs (Compilation Unit) */
658    while (!dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
659        /* Get the DIE(Debugging Information Entry) of this CU */
660        diep = dwarf_offdie(dbg, off + cuhl, &pf.cu_die);
661        if (!diep)
662            continue;
663
664        /* Check if target file is included. */
665        if (pp->file)
666            pf.fname = cu_find_realpath(&pf.cu_die, pp->file);
667        else
668            pf.fname = NULL;
669
670        if (!pp->file || pf.fname) {
671            if (pp->function)
672                find_probe_point_by_func(&pf);
673            else if (pp->lazy_line)
674                find_probe_point_lazy(NULL, &pf);
675            else {
676                pf.lno = pp->line;
677                find_probe_point_by_line(&pf);
678            }
679        }
680        off = noff;
681    }
682    line_list__free(&pf.lcache);
683    dwarf_end(dbg);
684
685    return pp->found;
686}
687
688/* Find line range from its line number */
689static void find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
690{
691    Dwarf_Lines *lines;
692    Dwarf_Line *line;
693    size_t nlines, i;
694    Dwarf_Addr addr;
695    int lineno;
696    int ret;
697    const char *src;
698    Dwarf_Die die_mem;
699
700    line_list__init(&lf->lr->line_list);
701    ret = dwarf_getsrclines(&lf->cu_die, &lines, &nlines);
702    DIE_IF(ret != 0);
703
704    for (i = 0; i < nlines; i++) {
705        line = dwarf_onesrcline(lines, i);
706        ret = dwarf_lineno(line, &lineno);
707        DIE_IF(ret != 0);
708        if (lf->lno_s > lineno || lf->lno_e < lineno)
709            continue;
710
711        if (sp_die) {
712            /* Address filtering 1: does sp_die include addr? */
713            ret = dwarf_lineaddr(line, &addr);
714            DIE_IF(ret != 0);
715            if (!dwarf_haspc(sp_die, addr))
716                continue;
717
718            /* Address filtering 2: No child include addr? */
719            if (die_get_inlinefunc(sp_die, addr, &die_mem))
720                continue;
721        }
722
723        /* TODO: Get fileno from line, but how? */
724        src = dwarf_linesrc(line, NULL, NULL);
725        if (strtailcmp(src, lf->fname) != 0)
726            continue;
727
728        /* Copy real path */
729        if (!lf->lr->path)
730            lf->lr->path = strdup(src);
731        line_list__add_line(&lf->lr->line_list, (unsigned int)lineno);
732    }
733    /* Update status */
734    if (!list_empty(&lf->lr->line_list))
735        lf->found = 1;
736    else {
737        free(lf->lr->path);
738        lf->lr->path = NULL;
739    }
740}
741
742static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
743{
744    find_line_range_by_line(in_die, (struct line_finder *)data);
745    return DWARF_CB_ABORT; /* No need to find other instances */
746}
747
748/* Search function from function name */
749static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
750{
751    struct line_finder *lf = (struct line_finder *)data;
752    struct line_range *lr = lf->lr;
753
754    if (dwarf_tag(sp_die) == DW_TAG_subprogram &&
755        die_compare_name(sp_die, lr->function) == 0) {
756        lf->fname = dwarf_decl_file(sp_die);
757        dwarf_decl_line(sp_die, &lr->offset);
758        pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
759        lf->lno_s = lr->offset + lr->start;
760        if (!lr->end)
761            lf->lno_e = INT_MAX;
762        else
763            lf->lno_e = lr->offset + lr->end;
764        lr->start = lf->lno_s;
765        lr->end = lf->lno_e;
766        if (dwarf_func_inline(sp_die))
767            dwarf_func_inline_instances(sp_die,
768                            line_range_inline_cb, lf);
769        else
770            find_line_range_by_line(sp_die, lf);
771        return 1;
772    }
773    return 0;
774}
775
776static void find_line_range_by_func(struct line_finder *lf)
777{
778    dwarf_getfuncs(&lf->cu_die, line_range_search_cb, lf, 0);
779}
780
781int find_line_range(int fd, struct line_range *lr)
782{
783    struct line_finder lf = {.lr = lr, .found = 0};
784    int ret;
785    Dwarf_Off off = 0, noff;
786    size_t cuhl;
787    Dwarf_Die *diep;
788    Dwarf *dbg;
789
790    dbg = dwarf_begin(fd, DWARF_C_READ);
791    if (!dbg)
792        return -ENOENT;
793
794    /* Loop on CUs (Compilation Unit) */
795    while (!lf.found) {
796        ret = dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL);
797        if (ret != 0)
798            break;
799
800        /* Get the DIE(Debugging Information Entry) of this CU */
801        diep = dwarf_offdie(dbg, off + cuhl, &lf.cu_die);
802        if (!diep)
803            continue;
804
805        /* Check if target file is included. */
806        if (lr->file)
807            lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
808        else
809            lf.fname = 0;
810
811        if (!lr->file || lf.fname) {
812            if (lr->function)
813                find_line_range_by_func(&lf);
814            else {
815                lf.lno_s = lr->start;
816                if (!lr->end)
817                    lf.lno_e = INT_MAX;
818                else
819                    lf.lno_e = lr->end;
820                find_line_range_by_line(NULL, &lf);
821            }
822        }
823        off = noff;
824    }
825    pr_debug("path: %lx\n", (unsigned long)lr->path);
826    dwarf_end(dbg);
827    return lf.found;
828}
829
830

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