/* * probe-finder.c : C expression to kprobe event converter * * Written by Masami Hiramatsu * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * */ #include #include #include #include #include #include #include #include #include #include #include #include #include "event.h" #include "dso.h" #include "debug.h" #include "intlist.h" #include "util.h" #include "symbol.h" #include "probe-finder.h" #include "probe-file.h" /* Kprobe tracer basic type is up to u64 */ #define MAX_BASIC_TYPE_BITS 64 /* Dwarf FL wrappers */ static char *debuginfo_path; /* Currently dummy */ static const Dwfl_Callbacks offline_callbacks = { .find_debuginfo = dwfl_standard_find_debuginfo, .debuginfo_path = &debuginfo_path, .section_address = dwfl_offline_section_address, /* We use this table for core files too. */ .find_elf = dwfl_build_id_find_elf, }; /* Get a Dwarf from offline image */ static int debuginfo__init_offline_dwarf(struct debuginfo *dbg, const char *path) { int fd; fd = open(path, O_RDONLY); if (fd < 0) return fd; dbg->dwfl = dwfl_begin(&offline_callbacks); if (!dbg->dwfl) goto error; dwfl_report_begin(dbg->dwfl); dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd); if (!dbg->mod) goto error; dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias); if (!dbg->dbg) goto error; dwfl_report_end(dbg->dwfl, NULL, NULL); return 0; error: if (dbg->dwfl) dwfl_end(dbg->dwfl); else close(fd); memset(dbg, 0, sizeof(*dbg)); return -ENOENT; } static struct debuginfo *__debuginfo__new(const char *path) { struct debuginfo *dbg = zalloc(sizeof(*dbg)); if (!dbg) return NULL; if (debuginfo__init_offline_dwarf(dbg, path) < 0) zfree(&dbg); if (dbg) pr_debug("Open Debuginfo file: %s\n", path); return dbg; } enum dso_binary_type distro_dwarf_types[] = { DSO_BINARY_TYPE__FEDORA_DEBUGINFO, DSO_BINARY_TYPE__UBUNTU_DEBUGINFO, DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO, DSO_BINARY_TYPE__BUILDID_DEBUGINFO, DSO_BINARY_TYPE__NOT_FOUND, }; struct debuginfo *debuginfo__new(const char *path) { enum dso_binary_type *type; char buf[PATH_MAX], nil = '\0'; struct dso *dso; struct debuginfo *dinfo = NULL; /* Try to open distro debuginfo files */ dso = dso__new(path); if (!dso) goto out; for (type = distro_dwarf_types; !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND; type++) { if (dso__read_binary_type_filename(dso, *type, &nil, buf, PATH_MAX) < 0) continue; dinfo = __debuginfo__new(buf); } dso__put(dso); out: /* if failed to open all distro debuginfo, open given binary */ return dinfo ? : __debuginfo__new(path); } void debuginfo__delete(struct debuginfo *dbg) { if (dbg) { if (dbg->dwfl) dwfl_end(dbg->dwfl); free(dbg); } } /* * Probe finder related functions */ static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs) { struct probe_trace_arg_ref *ref; ref = zalloc(sizeof(struct probe_trace_arg_ref)); if (ref != NULL) ref->offset = offs; return ref; } /* * Convert a location into trace_arg. * If tvar == NULL, this just checks variable can be converted. * If fentry == true and vr_die is a parameter, do huristic search * for the location fuzzed by function entry mcount. */ static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr, Dwarf_Op *fb_ops, Dwarf_Die *sp_die, unsigned int machine, struct probe_trace_arg *tvar) { Dwarf_Attribute attr; Dwarf_Addr tmp = 0; Dwarf_Op *op; size_t nops; unsigned int regn; Dwarf_Word offs = 0; bool ref = false; const char *regs; int ret, ret2 = 0; if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL) goto static_var; /* TODO: handle more than 1 exprs */ if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL) return -EINVAL; /* Broken DIE ? */ if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) { ret = dwarf_entrypc(sp_die, &tmp); if (ret) return -ENOENT; if (probe_conf.show_location_range && (dwarf_tag(vr_die) == DW_TAG_variable)) { ret2 = -ERANGE; } else if (addr != tmp || dwarf_tag(vr_die) != DW_TAG_formal_parameter) { return -ENOENT; } ret = dwarf_highpc(sp_die, &tmp); if (ret) return -ENOENT; /* * This is fuzzed by fentry mcount. We try to find the * parameter location at the earliest address. */ for (addr += 1; addr <= tmp; addr++) { if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) > 0) goto found; } return -ENOENT; } found: if (nops == 0) /* TODO: Support const_value */ return -ENOENT; if (op->atom == DW_OP_addr) { static_var: if (!tvar) return ret2; /* Static variables on memory (not stack), make @varname */ ret = strlen(dwarf_diename(vr_die)); tvar->value = zalloc(ret + 2); if (tvar->value == NULL) return -ENOMEM; snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die)); tvar->ref = alloc_trace_arg_ref((long)offs); if (tvar->ref == NULL) return -ENOMEM; return ret2; } /* If this is based on frame buffer, set the offset */ if (op->atom == DW_OP_fbreg) { if (fb_ops == NULL) return -ENOTSUP; ref = true; offs = op->number; op = &fb_ops[0]; } if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) { regn = op->atom - DW_OP_breg0; offs += op->number; ref = true; } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) { regn = op->atom - DW_OP_reg0; } else if (op->atom == DW_OP_bregx) { regn = op->number; offs += op->number2; ref = true; } else if (op->atom == DW_OP_regx) { regn = op->number; } else { pr_debug("DW_OP %x is not supported.\n", op->atom); return -ENOTSUP; } if (!tvar) return ret2; regs = get_dwarf_regstr(regn, machine); if (!regs) { /* This should be a bug in DWARF or this tool */ pr_warning("Mapping for the register number %u " "missing on this architecture.\n", regn); return -ENOTSUP; } tvar->value = strdup(regs); if (tvar->value == NULL) return -ENOMEM; if (ref) { tvar->ref = alloc_trace_arg_ref((long)offs); if (tvar->ref == NULL) return -ENOMEM; } return ret2; } #define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long)) static int convert_variable_type(Dwarf_Die *vr_die, struct probe_trace_arg *tvar, const char *cast) { struct probe_trace_arg_ref **ref_ptr = &tvar->ref; Dwarf_Die type; char buf[16]; char sbuf[STRERR_BUFSIZE]; int bsize, boffs, total; int ret; char prefix; /* TODO: check all types */ if (cast && strcmp(cast, "string") != 0 && strcmp(cast, "x") != 0 && strcmp(cast, "s") != 0 && strcmp(cast, "u") != 0) { /* Non string type is OK */ /* and respect signedness/hexadecimal cast */ tvar->type = strdup(cast); return (tvar->type == NULL) ? -ENOMEM : 0; } bsize = dwarf_bitsize(vr_die); if (bsize > 0) { /* This is a bitfield */ boffs = dwarf_bitoffset(vr_die); total = dwarf_bytesize(vr_die); if (boffs < 0 || total < 0) return -ENOENT; ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs, BYTES_TO_BITS(total)); goto formatted; } if (die_get_real_type(vr_die, &type) == NULL) { pr_warning("Failed to get a type information of %s.\n", dwarf_diename(vr_die)); return -ENOENT; } pr_debug("%s type is %s.\n", dwarf_diename(vr_die), dwarf_diename(&type)); if (cast && strcmp(cast, "string") == 0) { /* String type */ ret = dwarf_tag(&type); if (ret != DW_TAG_pointer_type && ret != DW_TAG_array_type) { pr_warning("Failed to cast into string: " "%s(%s) is not a pointer nor array.\n", dwarf_diename(vr_die), dwarf_diename(&type)); return -EINVAL; } if (die_get_real_type(&type, &type) == NULL) { pr_warning("Failed to get a type" " information.\n"); return -ENOENT; } if (ret == DW_TAG_pointer_type) { while (*ref_ptr) ref_ptr = &(*ref_ptr)->next; /* Add new reference with offset +0 */ *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref)); if (*ref_ptr == NULL) { pr_warning("Out of memory error\n"); return -ENOMEM; } } if (!die_compare_name(&type, "char") && !die_compare_name(&type, "unsigned char")) { pr_warning("Failed to cast into string: " "%s is not (unsigned) char *.\n", dwarf_diename(vr_die)); return -EINVAL; } tvar->type = strdup(cast); return (tvar->type == NULL) ? -ENOMEM : 0; } if (cast && (strcmp(cast, "u") == 0)) prefix = 'u'; else if (cast && (strcmp(cast, "s") == 0)) prefix = 's'; else if (cast && (strcmp(cast, "x") == 0) && probe_type_is_available(PROBE_TYPE_X)) prefix = 'x'; else prefix = die_is_signed_type(&type) ? 's' : probe_type_is_available(PROBE_TYPE_X) ? 'x' : 'u'; ret = dwarf_bytesize(&type); if (ret <= 0) /* No size ... try to use default type */ return 0; ret = BYTES_TO_BITS(ret); /* Check the bitwidth */ if (ret > MAX_BASIC_TYPE_BITS) { pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n", dwarf_diename(&type), MAX_BASIC_TYPE_BITS); ret = MAX_BASIC_TYPE_BITS; } ret = snprintf(buf, 16, "%c%d", prefix, ret); formatted: if (ret < 0 || ret >= 16) { if (ret >= 16) ret = -E2BIG; pr_warning("Failed to convert variable type: %s\n", str_error_r(-ret, sbuf, sizeof(sbuf))); return ret; } tvar->type = strdup(buf); if (tvar->type == NULL) return -ENOMEM; return 0; } static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname, struct perf_probe_arg_field *field, struct probe_trace_arg_ref **ref_ptr, Dwarf_Die *die_mem) { struct probe_trace_arg_ref *ref = *ref_ptr; Dwarf_Die type; Dwarf_Word offs; int ret, tag; pr_debug("converting %s in %s\n", field->name, varname); if (die_get_real_type(vr_die, &type) == NULL) { pr_warning("Failed to get the type of %s.\n", varname); return -ENOENT; } pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type)); tag = dwarf_tag(&type); if (field->name[0] == '[' && (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) { if (field->next) /* Save original type for next field */ memcpy(die_mem, &type, sizeof(*die_mem)); /* Get the type of this array */ if (die_get_real_type(&type, &type) == NULL) { pr_warning("Failed to get the type of %s.\n", varname); return -ENOENT; } pr_debug2("Array real type: (%x)\n", (unsigned)dwarf_dieoffset(&type)); if (tag == DW_TAG_pointer_type) { ref = zalloc(sizeof(struct probe_trace_arg_ref)); if (ref == NULL) return -ENOMEM; if (*ref_ptr) (*ref_ptr)->next = ref; else *ref_ptr = ref; } ref->offset += dwarf_bytesize(&type) * field->index; if (!field->next) /* Save vr_die for converting types */ memcpy(die_mem, vr_die, sizeof(*die_mem)); goto next; } else if (tag == DW_TAG_pointer_type) { /* Check the pointer and dereference */ if (!field->ref) { pr_err("Semantic error: %s must be referred by '->'\n", field->name); return -EINVAL; } /* Get the type pointed by this pointer */ if (die_get_real_type(&type, &type) == NULL) { pr_warning("Failed to get the type of %s.\n", varname); return -ENOENT; } /* Verify it is a data structure */ tag = dwarf_tag(&type); if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) { pr_warning("%s is not a data structure nor an union.\n", varname); return -EINVAL; } ref = zalloc(sizeof(struct probe_trace_arg_ref)); if (ref == NULL) return -ENOMEM; if (*ref_ptr) (*ref_ptr)->next = ref; else *ref_ptr = ref; } else { /* Verify it is a data structure */ if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) { pr_warning("%s is not a data structure nor an union.\n", varname); return -EINVAL; } if (field->name[0] == '[') { pr_err("Semantic error: %s is not a pointer" " nor array.\n", varname); return -EINVAL; } /* While prcessing unnamed field, we don't care about this */ if (field->ref && dwarf_diename(vr_die)) { pr_err("Semantic error: %s must be referred by '.'\n", field->name); return -EINVAL; } if (!ref) { pr_warning("Structure on a register is not " "supported yet.\n"); return -ENOTSUP; } } if (die_find_member(&type, field->name, die_mem) == NULL) { pr_warning("%s(type:%s) has no member %s.\n", varname, dwarf_diename(&type), field->name); return -EINVAL; } /* Get the offset of the field */ if (tag == DW_TAG_union_type) { offs = 0; } else { ret = die_get_data_member_location(die_mem, &offs); if (ret < 0) { pr_warning("Failed to get the offset of %s.\n", field->name); return ret; } } ref->offset += (long)offs; /* If this member is unnamed, we need to reuse this field */ if (!dwarf_diename(die_mem)) return convert_variable_fields(die_mem, varname, field, &ref, die_mem); next: /* Converting next field */ if (field->next) return convert_variable_fields(die_mem, field->name, field->next, &ref, die_mem); else return 0; } /* Show a variables in kprobe event format */ static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf) { Dwarf_Die die_mem; int ret; pr_debug("Converting variable %s into trace event.\n", dwarf_diename(vr_die)); ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops, &pf->sp_die, pf->machine, pf->tvar); if (ret == -ENOENT || ret == -EINVAL) { pr_err("Failed to find the location of the '%s' variable at this address.\n" " Perhaps it has been optimized out.\n" " Use -V with the --range option to show '%s' location range.\n", pf->pvar->var, pf->pvar->var); } else if (ret == -ENOTSUP) pr_err("Sorry, we don't support this variable location yet.\n"); else if (ret == 0 && pf->pvar->field) { ret = convert_variable_fields(vr_die, pf->pvar->var, pf->pvar->field, &pf->tvar->ref, &die_mem); vr_die = &die_mem; } if (ret == 0) ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type); /* *expr will be cached in libdw. Don't free it. */ return ret; } /* Find a variable in a scope DIE */ static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf) { Dwarf_Die vr_die; char *buf, *ptr; int ret = 0; /* Copy raw parameters */ if (!is_c_varname(pf->pvar->var)) return copy_to_probe_trace_arg(pf->tvar, pf->pvar); if (pf->pvar->name) pf->tvar->name = strdup(pf->pvar->name); else { buf = synthesize_perf_probe_arg(pf->pvar); if (!buf) return -ENOMEM; ptr = strchr(buf, ':'); /* Change type separator to _ */ if (ptr) *ptr = '_'; pf->tvar->name = buf; } if (pf->tvar->name == NULL) return -ENOMEM; pr_debug("Searching '%s' variable in context.\n", pf->pvar->var); /* Search child die for local variables and parameters. */ if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) { /* Search again in global variables */ if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, 0, &vr_die)) { pr_warning("Failed to find '%s' in this function.\n", pf->pvar->var); ret = -ENOENT; } } if (ret >= 0) ret = convert_variable(&vr_die, pf); return ret; } /* Convert subprogram DIE to trace point */ static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod, Dwarf_Addr paddr, bool retprobe, const char *function, struct probe_trace_point *tp) { Dwarf_Addr eaddr, highaddr; GElf_Sym sym; const char *symbol; /* Verify the address is correct */ if (dwarf_entrypc(sp_die, &eaddr) != 0) { pr_warning("Failed to get entry address of %s\n", dwarf_diename(sp_die)); return -ENOENT; } if (dwarf_highpc(sp_die, &highaddr) != 0) { pr_warning("Failed to get end address of %s\n", dwarf_diename(sp_die)); return -ENOENT; } if (paddr > highaddr) { pr_warning("Offset specified is greater than size of %s\n", dwarf_diename(sp_die)); return -EINVAL; } symbol = dwarf_diename(sp_die); if (!symbol) { /* Try to get the symbol name from symtab */ symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL); if (!symbol) { pr_warning("Failed to find symbol at 0x%lx\n", (unsigned long)paddr); return -ENOENT; } eaddr = sym.st_value; } tp->offset = (unsigned long)(paddr - eaddr); tp->address = (unsigned long)paddr; tp->symbol = strdup(symbol); if (!tp->symbol) return -ENOMEM; /* Return probe must be on the head of a subprogram */ if (retprobe) { if (eaddr != paddr) { pr_warning("Failed to find \"%s%%return\",\n" " because %s is an inlined function and" " has no return point.\n", function, function); return -EINVAL; } tp->retprobe = true; } return 0; } /* Call probe_finder callback with scope DIE */ static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf) { Dwarf_Attribute fb_attr; Dwarf_Frame *frame = NULL; size_t nops; int ret; if (!sc_die) { pr_err("Caller must pass a scope DIE. Program error.\n"); return -EINVAL; } /* If not a real subprogram, find a real one */ if (!die_is_func_def(sc_die)) { if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) { if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) { pr_warning("Ignoring tail call from %s\n", dwarf_diename(&pf->sp_die)); return 0; } else { pr_warning("Failed to find probe point in any " "functions.\n"); return -ENOENT; } } } else memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die)); /* Get the frame base attribute/ops from subprogram */ dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr); ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1); if (ret <= 0 || nops == 0) { pf->fb_ops = NULL; #if _ELFUTILS_PREREQ(0, 142) } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa && (pf->cfi_eh != NULL || pf->cfi_dbg != NULL)) { if ((dwarf_cfi_addrframe(pf->cfi_eh, pf->addr, &frame) != 0 && (dwarf_cfi_addrframe(pf->cfi_dbg, pf->addr, &frame) != 0)) || dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) { pr_warning("Failed to get call frame on 0x%jx\n", (uintmax_t)pf->addr); free(frame); return -ENOENT; } #endif } /* Call finder's callback handler */ ret = pf->callback(sc_die, pf); /* Since *pf->fb_ops can be a part of frame. we should free it here. */ free(frame); pf->fb_ops = NULL; return ret; } struct find_scope_param { const char *function; const char *file; int line; int diff; Dwarf_Die *die_mem; bool found; }; static int find_best_scope_cb(Dwarf_Die *fn_die, void *data) { struct find_scope_param *fsp = data; const char *file; int lno; /* Skip if declared file name does not match */ if (fsp->file) { file = dwarf_decl_file(fn_die); if (!file || strcmp(fsp->file, file) != 0) return 0; } /* If the function name is given, that's what user expects */ if (fsp->function) { if (die_match_name(fn_die, fsp->function)) { memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die)); fsp->found = true; return 1; } } else { /* With the line number, find the nearest declared DIE */ dwarf_decl_line(fn_die, &lno); if (lno < fsp->line && fsp->diff > fsp->line - lno) { /* Keep a candidate and continue */ fsp->diff = fsp->line - lno; memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die)); fsp->found = true; } } return 0; } /* Find an appropriate scope fits to given conditions */ static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem) { struct find_scope_param fsp = { .function = pf->pev->point.function, .file = pf->fname, .line = pf->lno, .diff = INT_MAX, .die_mem = die_mem, .found = false, }; cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp); return fsp.found ? die_mem : NULL; } static int probe_point_line_walker(const char *fname, int lineno, Dwarf_Addr addr, void *data) { struct probe_finder *pf = data; Dwarf_Die *sc_die, die_mem; int ret; if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0) return 0; pf->addr = addr; sc_die = find_best_scope(pf, &die_mem); if (!sc_die) { pr_warning("Failed to find scope of probe point.\n"); return -ENOENT; } ret = call_probe_finder(sc_die, pf); /* Continue if no error, because the line will be in inline function */ return ret < 0 ? ret : 0; } /* Find probe point from its line number */ static int find_probe_point_by_line(struct probe_finder *pf) { return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf); } /* Find lines which match lazy pattern */ static int find_lazy_match_lines(struct intlist *list, const char *fname, const char *pat) { FILE *fp; char *line = NULL; size_t line_len; ssize_t len; int count = 0, linenum = 1; char sbuf[STRERR_BUFSIZE]; fp = fopen(fname, "r"); if (!fp) { pr_warning("Failed to open %s: %s\n", fname, str_error_r(errno, sbuf, sizeof(sbuf))); return -errno; } while ((len = getline(&line, &line_len, fp)) > 0) { if (line[len - 1] == '\n') line[len - 1] = '\0'; if (strlazymatch(line, pat)) { intlist__add(list, linenum); count++; } linenum++; } if (ferror(fp)) count = -errno; free(line); fclose(fp); if (count == 0) pr_debug("No matched lines found in %s.\n", fname); return count; } static int probe_point_lazy_walker(const char *fname, int lineno, Dwarf_Addr addr, void *data) { struct probe_finder *pf = data; Dwarf_Die *sc_die, die_mem; int ret; if (!intlist__has_entry(pf->lcache, lineno) || strtailcmp(fname, pf->fname) != 0) return 0; pr_debug("Probe line found: line:%d addr:0x%llx\n", lineno, (unsigned long long)addr); pf->addr = addr; pf->lno = lineno; sc_die = find_best_scope(pf, &die_mem); if (!sc_die) { pr_warning("Failed to find scope of probe point.\n"); return -ENOENT; } ret = call_probe_finder(sc_die, pf); /* * Continue if no error, because the lazy pattern will match * to other lines */ return ret < 0 ? ret : 0; } /* Find probe points from lazy pattern */ static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf) { int ret = 0; char *fpath; if (intlist__empty(pf->lcache)) { const char *comp_dir; comp_dir = cu_get_comp_dir(&pf->cu_die); ret = get_real_path(pf->fname, comp_dir, &fpath); if (ret < 0) { pr_warning("Failed to find source file path.\n"); return ret; } /* Matching lazy line pattern */ ret = find_lazy_match_lines(pf->lcache, fpath, pf->pev->point.lazy_line); free(fpath); if (ret <= 0) return ret; } return die_walk_lines(sp_die, probe_point_lazy_walker, pf); } static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf) { struct perf_probe_point *pp = &pf->pev->point; /* Not uprobe? */ if (!pf->pev->uprobes) return; /* Compiled with optimization? */ if (die_is_optimized_target(&pf->cu_die)) return; /* Don't know entrypc? */ if (!pf->addr) return; /* Only FUNC and FUNC@SRC are eligible. */ if (!pp->function || pp->line || pp->retprobe || pp->lazy_line || pp->offset || pp->abs_address) return; /* Not interested in func parameter? */ if (!perf_probe_with_var(pf->pev)) return; pr_info("Target program is compiled without optimization. Skipping prologue.\n" "Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n", pf->addr); die_skip_prologue(sp_die, &pf->cu_die, &pf->addr); } static int probe_point_inline_cb(Dwarf_Die *in_die, void *data) { struct probe_finder *pf = data; struct perf_probe_point *pp = &pf->pev->point; Dwarf_Addr addr; int ret; if (pp->lazy_line) ret = find_probe_point_lazy(in_die, pf); else { /* Get probe address */ if (dwarf_entrypc(in_die, &addr) != 0) { pr_warning("Failed to get entry address of %s.\n", dwarf_diename(in_die)); return -ENOENT; } pf->addr = addr; pf->addr += pp->offset; pr_debug("found inline addr: 0x%jx\n", (uintmax_t)pf->addr); ret = call_probe_finder(in_die, pf); } return ret; } /* Callback parameter with return value for libdw */ struct dwarf_callback_param { void *data; int retval; }; /* Search function from function name */ static int probe_point_search_cb(Dwarf_Die *sp_die, void *data) { struct dwarf_callback_param *param = data; struct probe_finder *pf = param->data; struct perf_probe_point *pp = &pf->pev->point; /* Check tag and diename */ if (!die_is_func_def(sp_die) || !die_match_name(sp_die, pp->function)) return DWARF_CB_OK; /* Check declared file */ if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die))) return DWARF_CB_OK; pr_debug("Matched function: %s [%lx]\n", dwarf_diename(sp_die), (unsigned long)dwarf_dieoffset(sp_die)); pf->fname = dwarf_decl_file(sp_die); if (pp->line) { /* Function relative line */ dwarf_decl_line(sp_die, &pf->lno); pf->lno += pp->line; param->retval = find_probe_point_by_line(pf); } else if (die_is_func_instance(sp_die)) { /* Instances always have the entry address */ dwarf_entrypc(sp_die, &pf->addr); /* Real function */ if (pp->lazy_line) param->retval = find_probe_point_lazy(sp_die, pf); else { skip_prologue(sp_die, pf); pf->addr += pp->offset; /* TODO: Check the address in this function */ param->retval = call_probe_finder(sp_die, pf); } } else if (!probe_conf.no_inlines) { /* Inlined function: search instances */ param->retval = die_walk_instances(sp_die, probe_point_inline_cb, (void *)pf); /* This could be a non-existed inline definition */ if (param->retval == -ENOENT) param->retval = 0; } /* We need to find other candidates */ if (strisglob(pp->function) && param->retval >= 0) { param->retval = 0; /* We have to clear the result */ return DWARF_CB_OK; } return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */ } static int find_probe_point_by_func(struct probe_finder *pf) { struct dwarf_callback_param _param = {.data = (void *)pf, .retval = 0}; dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0); return _param.retval; } struct pubname_callback_param { char *function; char *file; Dwarf_Die *cu_die; Dwarf_Die *sp_die; int found; }; static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data) { struct pubname_callback_param *param = data; if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) { if (dwarf_tag(param->sp_die) != DW_TAG_subprogram) return DWARF_CB_OK; if (die_match_name(param->sp_die, param->function)) { if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die)) return DWARF_CB_OK; if (param->file && strtailcmp(param->file, dwarf_decl_file(param->sp_die))) return DWARF_CB_OK; param->found = 1; return DWARF_CB_ABORT; } } return DWARF_CB_OK; } static int debuginfo__find_probe_location(struct debuginfo *dbg, struct probe_finder *pf) { struct perf_probe_point *pp = &pf->pev->point; Dwarf_Off off, noff; size_t cuhl; Dwarf_Die *diep; int ret = 0; off = 0; pf->lcache = intlist__new(NULL); if (!pf->lcache) return -ENOMEM; /* Fastpath: lookup by function name from .debug_pubnames section */ if (pp->function && !strisglob(pp->function)) { struct pubname_callback_param pubname_param = { .function = pp->function, .file = pp->file, .cu_die = &pf->cu_die, .sp_die = &pf->sp_die, .found = 0, }; struct dwarf_callback_param probe_param = { .data = pf, }; dwarf_getpubnames(dbg->dbg, pubname_search_cb, &pubname_param, 0); if (pubname_param.found) { ret = probe_point_search_cb(&pf->sp_die, &probe_param); if (ret) goto found; } } /* Loop on CUs (Compilation Unit) */ while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) { /* Get the DIE(Debugging Information Entry) of this CU */ diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die); if (!diep) continue; /* Check if target file is included. */ if (pp->file) pf->fname = cu_find_realpath(&pf->cu_die, pp->file); else pf->fname = NULL; if (!pp->file || pf->fname) { if (pp->function) ret = find_probe_point_by_func(pf); else if (pp->lazy_line) ret = find_probe_point_lazy(&pf->cu_die, pf); else { pf->lno = pp->line; ret = find_probe_point_by_line(pf); } if (ret < 0) break; } off = noff; } found: intlist__delete(pf->lcache); pf->lcache = NULL; return ret; } /* Find probe points from debuginfo */ static int debuginfo__find_probes(struct debuginfo *dbg, struct probe_finder *pf) { int ret = 0; Elf *elf; GElf_Ehdr ehdr; if (pf->cfi_eh || pf->cfi_dbg) return debuginfo__find_probe_location(dbg, pf); /* Get the call frame information from this dwarf */ elf = dwarf_getelf(dbg->dbg); if (elf == NULL) return -EINVAL; if (gelf_getehdr(elf, &ehdr) == NULL) return -EINVAL; pf->machine = ehdr.e_machine; #if _ELFUTILS_PREREQ(0, 142) do { GElf_Shdr shdr; if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) && shdr.sh_type == SHT_PROGBITS) pf->cfi_eh = dwarf_getcfi_elf(elf); pf->cfi_dbg = dwarf_getcfi(dbg->dbg); } while (0); #endif ret = debuginfo__find_probe_location(dbg, pf); return ret; } struct local_vars_finder { struct probe_finder *pf; struct perf_probe_arg *args; bool vars; int max_args; int nargs; int ret; }; /* Collect available variables in this scope */ static int copy_variables_cb(Dwarf_Die *die_mem, void *data) { struct local_vars_finder *vf = data; struct probe_finder *pf = vf->pf; int tag; tag = dwarf_tag(die_mem); if (tag == DW_TAG_formal_parameter || (tag == DW_TAG_variable && vf->vars)) { if (convert_variable_location(die_mem, vf->pf->addr, vf->pf->fb_ops, &pf->sp_die, pf->machine, NULL) == 0) { vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem); if (vf->args[vf->nargs].var == NULL) { vf->ret = -ENOMEM; return DIE_FIND_CB_END; } pr_debug(" %s", vf->args[vf->nargs].var); vf->nargs++; } } if (dwarf_haspc(die_mem, vf->pf->addr)) return DIE_FIND_CB_CONTINUE; else return DIE_FIND_CB_SIBLING; } static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf, struct perf_probe_arg *args) { Dwarf_Die die_mem; int i; int n = 0; struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false, .max_args = MAX_PROBE_ARGS, .ret = 0}; for (i = 0; i < pf->pev->nargs; i++) { /* var never be NULL */ if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0) vf.vars = true; else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) { /* Copy normal argument */ args[n] = pf->pev->args[i]; n++; continue; } pr_debug("Expanding %s into:", pf->pev->args[i].var); vf.nargs = n; /* Special local variables */ die_find_child(sc_die, copy_variables_cb, (void *)&vf, &die_mem); pr_debug(" (%d)\n", vf.nargs - n); if (vf.ret < 0) return vf.ret; n = vf.nargs; } return n; } /* Add a found probe point into trace event list */ static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf) { struct trace_event_finder *tf = container_of(pf, struct trace_event_finder, pf); struct perf_probe_point *pp = &pf->pev->point; struct probe_trace_event *tev; struct perf_probe_arg *args = NULL; int ret, i; /* Check number of tevs */ if (tf->ntevs == tf->max_tevs) { pr_warning("Too many( > %d) probe point found.\n", tf->max_tevs); return -ERANGE; } tev = &tf->tevs[tf->ntevs++]; /* Trace point should be converted from subprogram DIE */ ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr, pp->retprobe, pp->function, &tev->point); if (ret < 0) goto end; tev->point.realname = strdup(dwarf_diename(sc_die)); if (!tev->point.realname) { ret = -ENOMEM; goto end; } pr_debug("Probe point found: %s+%lu\n", tev->point.symbol, tev->point.offset); /* Expand special probe argument if exist */ args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS); if (args == NULL) { ret = -ENOMEM; goto end; } ret = expand_probe_args(sc_die, pf, args); if (ret < 0) goto end; tev->nargs = ret; tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs); if (tev->args == NULL) { ret = -ENOMEM; goto end; } /* Find each argument */ for (i = 0; i < tev->nargs; i++) { pf->pvar = &args[i]; pf->tvar = &tev->args[i]; /* Variable should be found from scope DIE */ ret = find_variable(sc_die, pf); if (ret != 0) break; } end: if (ret) { clear_probe_trace_event(tev); tf->ntevs--; } free(args); return ret; } /* Find probe_trace_events specified by perf_probe_event from debuginfo */ int debuginfo__find_trace_events(struct debuginfo *dbg, struct perf_probe_event *pev, struct probe_trace_event **tevs) { struct trace_event_finder tf = { .pf = {.pev = pev, .callback = add_probe_trace_event}, .max_tevs = probe_conf.max_probes, .mod = dbg->mod}; int ret, i; /* Allocate result tevs array */ *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs); if (*tevs == NULL) return -ENOMEM; tf.tevs = *tevs; tf.ntevs = 0; ret = debuginfo__find_probes(dbg, &tf.pf); if (ret < 0) { for (i = 0; i < tf.ntevs; i++) clear_probe_trace_event(&tf.tevs[i]); zfree(tevs); return ret; } return (ret < 0) ? ret : tf.ntevs; } /* Collect available variables in this scope */ static int collect_variables_cb(Dwarf_Die *die_mem, void *data) { struct available_var_finder *af = data; struct variable_list *vl; struct strbuf buf = STRBUF_INIT; int tag, ret; vl = &af->vls[af->nvls - 1]; tag = dwarf_tag(die_mem); if (tag == DW_TAG_formal_parameter || tag == DW_TAG_variable) { ret = convert_variable_location(die_mem, af->pf.addr, af->pf.fb_ops, &af->pf.sp_die, af->pf.machine, NULL); if (ret == 0 || ret == -ERANGE) { int ret2; bool externs = !af->child; if (strbuf_init(&buf, 64) < 0) goto error; if (probe_conf.show_location_range) { if (!externs) ret2 = strbuf_add(&buf, ret ? "[INV]\t" : "[VAL]\t", 6); else ret2 = strbuf_add(&buf, "[EXT]\t", 6); if (ret2) goto error; } ret2 = die_get_varname(die_mem, &buf); if (!ret2 && probe_conf.show_location_range && !externs) { if (strbuf_addch(&buf, '\t') < 0) goto error; ret2 = die_get_var_range(&af->pf.sp_die, die_mem, &buf); } pr_debug("Add new var: %s\n", buf.buf); if (ret2 == 0) { strlist__add(vl->vars, strbuf_detach(&buf, NULL)); } strbuf_release(&buf); } } if (af->child && dwarf_haspc(die_mem, af->pf.addr)) return DIE_FIND_CB_CONTINUE; else return DIE_FIND_CB_SIBLING; error: strbuf_release(&buf); pr_debug("Error in strbuf\n"); return DIE_FIND_CB_END; } /* Add a found vars into available variables list */ static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf) { struct available_var_finder *af = container_of(pf, struct available_var_finder, pf); struct perf_probe_point *pp = &pf->pev->point; struct variable_list *vl; Dwarf_Die die_mem; int ret; /* Check number of tevs */ if (af->nvls == af->max_vls) { pr_warning("Too many( > %d) probe point found.\n", af->max_vls); return -ERANGE; } vl = &af->vls[af->nvls++]; /* Trace point should be converted from subprogram DIE */ ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr, pp->retprobe, pp->function, &vl->point); if (ret < 0) return ret; pr_debug("Probe point found: %s+%lu\n", vl->point.symbol, vl->point.offset); /* Find local variables */ vl->vars = strlist__new(NULL, NULL); if (vl->vars == NULL) return -ENOMEM; af->child = true; die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem); /* Find external variables */ if (!probe_conf.show_ext_vars) goto out; /* Don't need to search child DIE for external vars. */ af->child = false; die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem); out: if (strlist__empty(vl->vars)) { strlist__delete(vl->vars); vl->vars = NULL; } return ret; } /* * Find available variables at given probe point * Return the number of found probe points. Return 0 if there is no * matched probe point. Return <0 if an error occurs. */ int debuginfo__find_available_vars_at(struct debuginfo *dbg, struct perf_probe_event *pev, struct variable_list **vls) { struct available_var_finder af = { .pf = {.pev = pev, .callback = add_available_vars}, .mod = dbg->mod, .max_vls = probe_conf.max_probes}; int ret; /* Allocate result vls array */ *vls = zalloc(sizeof(struct variable_list) * af.max_vls); if (*vls == NULL) return -ENOMEM; af.vls = *vls; af.nvls = 0; ret = debuginfo__find_probes(dbg, &af.pf); if (ret < 0) { /* Free vlist for error */ while (af.nvls--) { zfree(&af.vls[af.nvls].point.symbol); strlist__delete(af.vls[af.nvls].vars); } zfree(vls); return ret; } return (ret < 0) ? ret : af.nvls; } /* For the kernel module, we need a special code to get a DIE */ static int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs) { int n, i; Elf32_Word shndx; Elf_Scn *scn; Elf *elf; GElf_Shdr mem, *shdr; const char *p; elf = dwfl_module_getelf(dbg->mod, &dbg->bias); if (!elf) return -EINVAL; /* Get the number of relocations */ n = dwfl_module_relocations(dbg->mod); if (n < 0) return -ENOENT; /* Search the relocation related .text section */ for (i = 0; i < n; i++) { p = dwfl_module_relocation_info(dbg->mod, i, &shndx); if (strcmp(p, ".text") == 0) { /* OK, get the section header */ scn = elf_getscn(elf, shndx); if (!scn) return -ENOENT; shdr = gelf_getshdr(scn, &mem); if (!shdr) return -ENOENT; *offs = shdr->sh_addr; } } return 0; } /* Reverse search */ int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr, struct perf_probe_point *ppt) { Dwarf_Die cudie, spdie, indie; Dwarf_Addr _addr = 0, baseaddr = 0; const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp; int baseline = 0, lineno = 0, ret = 0; bool reloc = false; retry: /* Find cu die */ if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) { if (!reloc && debuginfo__get_text_offset(dbg, &baseaddr) == 0) { addr += baseaddr; reloc = true; goto retry; } pr_warning("Failed to find debug information for address %lx\n", addr); ret = -EINVAL; goto end; } /* Find a corresponding line (filename and lineno) */ cu_find_lineinfo(&cudie, addr, &fname, &lineno); /* Don't care whether it failed or not */ /* Find a corresponding function (name, baseline and baseaddr) */ if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) { /* Get function entry information */ func = basefunc = dwarf_diename(&spdie); if (!func || dwarf_entrypc(&spdie, &baseaddr) != 0 || dwarf_decl_line(&spdie, &baseline) != 0) { lineno = 0; goto post; } fname = dwarf_decl_file(&spdie); if (addr == (unsigned long)baseaddr) { /* Function entry - Relative line number is 0 */ lineno = baseline; goto post; } /* Track down the inline functions step by step */ while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr, &indie)) { /* There is an inline function */ if (dwarf_entrypc(&indie, &_addr) == 0 && _addr == addr) { /* * addr is at an inline function entry. * In this case, lineno should be the call-site * line number. (overwrite lineinfo) */ lineno = die_get_call_lineno(&indie); fname = die_get_call_file(&indie); break; } else { /* * addr is in an inline function body. * Since lineno points one of the lines * of the inline function, baseline should * be the entry line of the inline function. */ tmp = dwarf_diename(&indie); if (!tmp || dwarf_decl_line(&indie, &baseline) != 0) break; func = tmp; spdie = indie; } } /* Verify the lineno and baseline are in a same file */ tmp = dwarf_decl_file(&spdie); if (!tmp || strcmp(tmp, fname) != 0) lineno = 0; } post: /* Make a relative line number or an offset */ if (lineno) ppt->line = lineno - baseline; else if (basefunc) { ppt->offset = addr - (unsigned long)baseaddr; func = basefunc; } /* Duplicate strings */ if (func) { ppt->function = strdup(func); if (ppt->function == NULL) { ret = -ENOMEM; goto end; } } if (fname) { ppt->file = strdup(fname); if (ppt->file == NULL) { zfree(&ppt->function); ret = -ENOMEM; goto end; } } end: if (ret == 0 && (fname || func)) ret = 1; /* Found a point */ return ret; } /* Add a line and store the src path */ static int line_range_add_line(const char *src, unsigned int lineno, struct line_range *lr) { /* Copy source path */ if (!lr->path) { lr->path = strdup(src); if (lr->path == NULL) return -ENOMEM; } return intlist__add(lr->line_list, lineno); } static int line_range_walk_cb(const char *fname, int lineno, Dwarf_Addr addr __maybe_unused, void *data) { struct line_finder *lf = data; int err; if ((strtailcmp(fname, lf->fname) != 0) || (lf->lno_s > lineno || lf->lno_e < lineno)) return 0; err = line_range_add_line(fname, lineno, lf->lr); if (err < 0 && err != -EEXIST) return err; return 0; } /* Find line range from its line number */ static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf) { int ret; ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf); /* Update status */ if (ret >= 0) if (!intlist__empty(lf->lr->line_list)) ret = lf->found = 1; else ret = 0; /* Lines are not found */ else { zfree(&lf->lr->path); } return ret; } static int line_range_inline_cb(Dwarf_Die *in_die, void *data) { int ret = find_line_range_by_line(in_die, data); /* * We have to check all instances of inlined function, because * some execution paths can be optimized out depends on the * function argument of instances. However, if an error occurs, * it should be handled by the caller. */ return ret < 0 ? ret : 0; } /* Search function definition from function name */ static int line_range_search_cb(Dwarf_Die *sp_die, void *data) { struct dwarf_callback_param *param = data; struct line_finder *lf = param->data; struct line_range *lr = lf->lr; /* Check declared file */ if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die))) return DWARF_CB_OK; if (die_is_func_def(sp_die) && die_match_name(sp_die, lr->function)) { lf->fname = dwarf_decl_file(sp_die); dwarf_decl_line(sp_die, &lr->offset); pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset); lf->lno_s = lr->offset + lr->start; if (lf->lno_s < 0) /* Overflow */ lf->lno_s = INT_MAX; lf->lno_e = lr->offset + lr->end; if (lf->lno_e < 0) /* Overflow */ lf->lno_e = INT_MAX; pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e); lr->start = lf->lno_s; lr->end = lf->lno_e; if (!die_is_func_instance(sp_die)) param->retval = die_walk_instances(sp_die, line_range_inline_cb, lf); else param->retval = find_line_range_by_line(sp_die, lf); return DWARF_CB_ABORT; } return DWARF_CB_OK; } static int find_line_range_by_func(struct line_finder *lf) { struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0}; dwarf_getfuncs(&lf->cu_die, line_range_search_cb, ¶m, 0); return param.retval; } int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr) { struct line_finder lf = {.lr = lr, .found = 0}; int ret = 0; Dwarf_Off off = 0, noff; size_t cuhl; Dwarf_Die *diep; const char *comp_dir; /* Fastpath: lookup by function name from .debug_pubnames section */ if (lr->function) { struct pubname_callback_param pubname_param = { .function = lr->function, .file = lr->file, .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0}; struct dwarf_callback_param line_range_param = { .data = (void *)&lf, .retval = 0}; dwarf_getpubnames(dbg->dbg, pubname_search_cb, &pubname_param, 0); if (pubname_param.found) { line_range_search_cb(&lf.sp_die, &line_range_param); if (lf.found) goto found; } } /* Loop on CUs (Compilation Unit) */ while (!lf.found && ret >= 0) { if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL) != 0) break; /* Get the DIE(Debugging Information Entry) of this CU */ diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die); if (!diep) continue; /* Check if target file is included. */ if (lr->file) lf.fname = cu_find_realpath(&lf.cu_die, lr->file); else lf.fname = 0; if (!lr->file || lf.fname) { if (lr->function) ret = find_line_range_by_func(&lf); else { lf.lno_s = lr->start; lf.lno_e = lr->end; ret = find_line_range_by_line(NULL, &lf); } } off = noff; } found: /* Store comp_dir */ if (lf.found) { comp_dir = cu_get_comp_dir(&lf.cu_die); if (comp_dir) { lr->comp_dir = strdup(comp_dir); if (!lr->comp_dir) ret = -ENOMEM; } } pr_debug("path: %s\n", lr->path); return (ret < 0) ? ret : lf.found; } /* * Find a src file from a DWARF tag path. Prepend optional source path prefix * and chop off leading directories that do not exist. Result is passed back as * a newly allocated path on success. * Return 0 if file was found and readable, -errno otherwise. */ int get_real_path(const char *raw_path, const char *comp_dir, char **new_path) { const char *prefix = symbol_conf.source_prefix; if (!prefix) { if (raw_path[0] != '/' && comp_dir) /* If not an absolute path, try to use comp_dir */ prefix = comp_dir; else { if (access(raw_path, R_OK) == 0) { *new_path = strdup(raw_path); return *new_path ? 0 : -ENOMEM; } else return -errno; } } *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2)); if (!*new_path) return -ENOMEM; for (;;) { sprintf(*new_path, "%s/%s", prefix, raw_path); if (access(*new_path, R_OK) == 0) return 0; if (!symbol_conf.source_prefix) { /* In case of searching comp_dir, don't retry */ zfree(new_path); return -errno; } switch (errno) { case ENAMETOOLONG: case ENOENT: case EROFS: case EFAULT: raw_path = strchr(++raw_path, '/'); if (!raw_path) { zfree(new_path); return -ENOENT; } continue; default: zfree(new_path); return -errno; } } }