/* * 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 #include #include "event.h" #include "debug.h" #include "util.h" #include "symbol.h" #include "probe-finder.h" /* Kprobe tracer basic type is up to u64 */ #define MAX_BASIC_TYPE_BITS 64 /* * Compare the tail of two strings. * Return 0 if whole of either string is same as another's tail part. */ static int strtailcmp(const char *s1, const char *s2) { int i1 = strlen(s1); int i2 = strlen(s2); while (--i1 >= 0 && --i2 >= 0) { if (s1[i1] != s2[i2]) return s1[i1] - s2[i2]; } return 0; } /* Line number list operations */ /* Add a line to line number list */ static int line_list__add_line(struct list_head *head, int line) { struct line_node *ln; struct list_head *p; /* Reverse search, because new line will be the last one */ list_for_each_entry_reverse(ln, head, list) { if (ln->line < line) { p = &ln->list; goto found; } else if (ln->line == line) /* Already exist */ return 1; } /* List is empty, or the smallest entry */ p = head; found: pr_debug("line list: add a line %u\n", line); ln = zalloc(sizeof(struct line_node)); if (ln == NULL) return -ENOMEM; ln->line = line; INIT_LIST_HEAD(&ln->list); list_add(&ln->list, p); return 0; } /* Check if the line in line number list */ static int line_list__has_line(struct list_head *head, int line) { struct line_node *ln; /* Reverse search, because new line will be the last one */ list_for_each_entry(ln, head, list) if (ln->line == line) return 1; return 0; } /* Init line number list */ static void line_list__init(struct list_head *head) { INIT_LIST_HEAD(head); } /* Free line number list */ static void line_list__free(struct list_head *head) { struct line_node *ln; while (!list_empty(head)) { ln = list_first_entry(head, struct line_node, list); list_del(&ln->list); free(ln); } } /* 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 Dwarf *dwfl_init_offline_dwarf(int fd, Dwfl **dwflp, Dwarf_Addr *bias) { Dwfl_Module *mod; Dwarf *dbg = NULL; if (!dwflp) return NULL; *dwflp = dwfl_begin(&offline_callbacks); if (!*dwflp) return NULL; mod = dwfl_report_offline(*dwflp, "", "", fd); if (!mod) goto error; dbg = dwfl_module_getdwarf(mod, bias); if (!dbg) { error: dwfl_end(*dwflp); *dwflp = NULL; } return dbg; } #if _ELFUTILS_PREREQ(0, 148) /* This method is buggy if elfutils is older than 0.148 */ static int __linux_kernel_find_elf(Dwfl_Module *mod, void **userdata, const char *module_name, Dwarf_Addr base, char **file_name, Elf **elfp) { int fd; const char *path = kernel_get_module_path(module_name); pr_debug2("Use file %s for %s\n", path, module_name); if (path) { fd = open(path, O_RDONLY); if (fd >= 0) { *file_name = strdup(path); return fd; } } /* If failed, try to call standard method */ return dwfl_linux_kernel_find_elf(mod, userdata, module_name, base, file_name, elfp); } static const Dwfl_Callbacks kernel_callbacks = { .find_debuginfo = dwfl_standard_find_debuginfo, .debuginfo_path = &debuginfo_path, .find_elf = __linux_kernel_find_elf, .section_address = dwfl_linux_kernel_module_section_address, }; /* Get a Dwarf from live kernel image */ static Dwarf *dwfl_init_live_kernel_dwarf(Dwarf_Addr addr, Dwfl **dwflp, Dwarf_Addr *bias) { Dwarf *dbg; if (!dwflp) return NULL; *dwflp = dwfl_begin(&kernel_callbacks); if (!*dwflp) return NULL; /* Load the kernel dwarves: Don't care the result here */ dwfl_linux_kernel_report_kernel(*dwflp); dwfl_linux_kernel_report_modules(*dwflp); dbg = dwfl_addrdwarf(*dwflp, addr, bias); /* Here, check whether we could get a real dwarf */ if (!dbg) { pr_debug("Failed to find kernel dwarf at %lx\n", (unsigned long)addr); dwfl_end(*dwflp); *dwflp = NULL; } return dbg; } #else /* With older elfutils, this just support kernel module... */ static Dwarf *dwfl_init_live_kernel_dwarf(Dwarf_Addr addr __used, Dwfl **dwflp, Dwarf_Addr *bias) { int fd; const char *path = kernel_get_module_path("kernel"); if (!path) { pr_err("Failed to find vmlinux path\n"); return NULL; } pr_debug2("Use file %s for debuginfo\n", path); fd = open(path, O_RDONLY); if (fd < 0) return NULL; return dwfl_init_offline_dwarf(fd, dwflp, bias); } #endif /* Dwarf wrappers */ /* Find the realpath of the target file. */ static const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname) { Dwarf_Files *files; size_t nfiles, i; const char *src = NULL; int ret; if (!fname) return NULL; ret = dwarf_getsrcfiles(cu_die, &files, &nfiles); if (ret != 0) return NULL; for (i = 0; i < nfiles; i++) { src = dwarf_filesrc(files, i, NULL, NULL); if (strtailcmp(src, fname) == 0) break; } if (i == nfiles) return NULL; return src; } /* Get DW_AT_comp_dir (should be NULL with older gcc) */ static const char *cu_get_comp_dir(Dwarf_Die *cu_die) { Dwarf_Attribute attr; if (dwarf_attr(cu_die, DW_AT_comp_dir, &attr) == NULL) return NULL; return dwarf_formstring(&attr); } /* Get a line number and file name for given address */ static int cu_find_lineinfo(Dwarf_Die *cudie, unsigned long addr, const char **fname, int *lineno) { Dwarf_Line *line; Dwarf_Addr laddr; line = dwarf_getsrc_die(cudie, (Dwarf_Addr)addr); if (line && dwarf_lineaddr(line, &laddr) == 0 && addr == (unsigned long)laddr && dwarf_lineno(line, lineno) == 0) { *fname = dwarf_linesrc(line, NULL, NULL); if (!*fname) /* line number is useless without filename */ *lineno = 0; } return *lineno ?: -ENOENT; } /* Compare diename and tname */ static bool die_compare_name(Dwarf_Die *dw_die, const char *tname) { const char *name; name = dwarf_diename(dw_die); return name ? (strcmp(tname, name) == 0) : false; } /* Get callsite line number of inline-function instance */ static int die_get_call_lineno(Dwarf_Die *in_die) { Dwarf_Attribute attr; Dwarf_Word ret; if (!dwarf_attr(in_die, DW_AT_call_line, &attr)) return -ENOENT; dwarf_formudata(&attr, &ret); return (int)ret; } /* Get type die */ static Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem) { Dwarf_Attribute attr; if (dwarf_attr_integrate(vr_die, DW_AT_type, &attr) && dwarf_formref_die(&attr, die_mem)) return die_mem; else return NULL; } /* Get a type die, but skip qualifiers */ static Dwarf_Die *__die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem) { int tag; do { vr_die = die_get_type(vr_die, die_mem); if (!vr_die) break; tag = dwarf_tag(vr_die); } while (tag == DW_TAG_const_type || tag == DW_TAG_restrict_type || tag == DW_TAG_volatile_type || tag == DW_TAG_shared_type); return vr_die; } /* Get a type die, but skip qualifiers and typedef */ static Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem) { do { vr_die = __die_get_real_type(vr_die, die_mem); } while (vr_die && dwarf_tag(vr_die) == DW_TAG_typedef); return vr_die; } static int die_get_attr_udata(Dwarf_Die *tp_die, unsigned int attr_name, Dwarf_Word *result) { Dwarf_Attribute attr; if (dwarf_attr(tp_die, attr_name, &attr) == NULL || dwarf_formudata(&attr, result) != 0) return -ENOENT; return 0; } static bool die_is_signed_type(Dwarf_Die *tp_die) { Dwarf_Word ret; if (die_get_attr_udata(tp_die, DW_AT_encoding, &ret)) return false; return (ret == DW_ATE_signed_char || ret == DW_ATE_signed || ret == DW_ATE_signed_fixed); } static int die_get_byte_size(Dwarf_Die *tp_die) { Dwarf_Word ret; if (die_get_attr_udata(tp_die, DW_AT_byte_size, &ret)) return 0; return (int)ret; } static int die_get_bit_size(Dwarf_Die *tp_die) { Dwarf_Word ret; if (die_get_attr_udata(tp_die, DW_AT_bit_size, &ret)) return 0; return (int)ret; } static int die_get_bit_offset(Dwarf_Die *tp_die) { Dwarf_Word ret; if (die_get_attr_udata(tp_die, DW_AT_bit_offset, &ret)) return 0; return (int)ret; } /* Get data_member_location offset */ static int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs) { Dwarf_Attribute attr; Dwarf_Op *expr; size_t nexpr; int ret; if (dwarf_attr(mb_die, DW_AT_data_member_location, &attr) == NULL) return -ENOENT; if (dwarf_formudata(&attr, offs) != 0) { /* DW_AT_data_member_location should be DW_OP_plus_uconst */ ret = dwarf_getlocation(&attr, &expr, &nexpr); if (ret < 0 || nexpr == 0) return -ENOENT; if (expr[0].atom != DW_OP_plus_uconst || nexpr != 1) { pr_debug("Unable to get offset:Unexpected OP %x (%zd)\n", expr[0].atom, nexpr); return -ENOTSUP; } *offs = (Dwarf_Word)expr[0].number; } return 0; } /* Return values for die_find callbacks */ enum { DIE_FIND_CB_FOUND = 0, /* End of Search */ DIE_FIND_CB_CHILD = 1, /* Search only children */ DIE_FIND_CB_SIBLING = 2, /* Search only siblings */ DIE_FIND_CB_CONTINUE = 3, /* Search children and siblings */ }; /* Search a child die */ static Dwarf_Die *die_find_child(Dwarf_Die *rt_die, int (*callback)(Dwarf_Die *, void *), void *data, Dwarf_Die *die_mem) { Dwarf_Die child_die; int ret; ret = dwarf_child(rt_die, die_mem); if (ret != 0) return NULL; do { ret = callback(die_mem, data); if (ret == DIE_FIND_CB_FOUND) return die_mem; if ((ret & DIE_FIND_CB_CHILD) && die_find_child(die_mem, callback, data, &child_die)) { memcpy(die_mem, &child_die, sizeof(Dwarf_Die)); return die_mem; } } while ((ret & DIE_FIND_CB_SIBLING) && dwarf_siblingof(die_mem, die_mem) == 0); return NULL; } struct __addr_die_search_param { Dwarf_Addr addr; Dwarf_Die *die_mem; }; static int __die_search_func_cb(Dwarf_Die *fn_die, void *data) { struct __addr_die_search_param *ad = data; if (dwarf_tag(fn_die) == DW_TAG_subprogram && dwarf_haspc(fn_die, ad->addr)) { memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die)); return DWARF_CB_ABORT; } return DWARF_CB_OK; } /* Search a real subprogram including this line, */ static Dwarf_Die *die_find_real_subprogram(Dwarf_Die *cu_die, Dwarf_Addr addr, Dwarf_Die *die_mem) { struct __addr_die_search_param ad; ad.addr = addr; ad.die_mem = die_mem; /* dwarf_getscopes can't find subprogram. */ if (!dwarf_getfuncs(cu_die, __die_search_func_cb, &ad, 0)) return NULL; else return die_mem; } /* die_find callback for inline function search */ static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data) { Dwarf_Addr *addr = data; if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine && dwarf_haspc(die_mem, *addr)) return DIE_FIND_CB_FOUND; return DIE_FIND_CB_CONTINUE; } /* Similar to dwarf_getfuncs, but returns inlined_subroutine if exists. */ static Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr, Dwarf_Die *die_mem) { Dwarf_Die tmp_die; sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr, &tmp_die); if (!sp_die) return NULL; /* Inlined function could be recursive. Trace it until fail */ while (sp_die) { memcpy(die_mem, sp_die, sizeof(Dwarf_Die)); sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr, &tmp_die); } return die_mem; } /* Walker on lines (Note: line number will not be sorted) */ typedef int (* line_walk_handler_t) (const char *fname, int lineno, Dwarf_Addr addr, void *data); struct __line_walk_param { const char *fname; line_walk_handler_t handler; void *data; int retval; }; static int __die_walk_funclines_cb(Dwarf_Die *in_die, void *data) { struct __line_walk_param *lw = data; Dwarf_Addr addr; int lineno; if (dwarf_tag(in_die) == DW_TAG_inlined_subroutine) { lineno = die_get_call_lineno(in_die); if (lineno > 0 && dwarf_entrypc(in_die, &addr) == 0) { lw->retval = lw->handler(lw->fname, lineno, addr, lw->data); if (lw->retval != 0) return DIE_FIND_CB_FOUND; } } return DIE_FIND_CB_SIBLING; } /* Walk on lines of blocks included in given DIE */ static int __die_walk_funclines(Dwarf_Die *sp_die, line_walk_handler_t handler, void *data) { struct __line_walk_param lw = { .handler = handler, .data = data, .retval = 0, }; Dwarf_Die die_mem; Dwarf_Addr addr; int lineno; /* Handle function declaration line */ lw.fname = dwarf_decl_file(sp_die); if (lw.fname && dwarf_decl_line(sp_die, &lineno) == 0 && dwarf_entrypc(sp_die, &addr) == 0) { lw.retval = handler(lw.fname, lineno, addr, data); if (lw.retval != 0) goto done; } die_find_child(sp_die, __die_walk_funclines_cb, &lw, &die_mem); done: return lw.retval; } static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data) { struct __line_walk_param *lw = data; lw->retval = __die_walk_funclines(sp_die, lw->handler, lw->data); if (lw->retval != 0) return DWARF_CB_ABORT; return DWARF_CB_OK; } /* * Walk on lines inside given PDIE. If the PDIE is subprogram, walk only on * the lines inside the subprogram, otherwise PDIE must be a CU DIE. */ static int die_walk_lines(Dwarf_Die *pdie, line_walk_handler_t handler, void *data) { Dwarf_Lines *lines; Dwarf_Line *line; Dwarf_Addr addr; const char *fname; int lineno, ret = 0; Dwarf_Die die_mem, *cu_die; size_t nlines, i; /* Get the CU die */ if (dwarf_tag(pdie) == DW_TAG_subprogram) cu_die = dwarf_diecu(pdie, &die_mem, NULL, NULL); else cu_die = pdie; if (!cu_die) { pr_debug2("Failed to get CU from subprogram\n"); return -EINVAL; } /* Get lines list in the CU */ if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0) { pr_debug2("Failed to get source lines on this CU.\n"); return -ENOENT; } pr_debug2("Get %zd lines from this CU\n", nlines); /* Walk on the lines on lines list */ for (i = 0; i < nlines; i++) { line = dwarf_onesrcline(lines, i); if (line == NULL || dwarf_lineno(line, &lineno) != 0 || dwarf_lineaddr(line, &addr) != 0) { pr_debug2("Failed to get line info. " "Possible error in debuginfo.\n"); continue; } /* Filter lines based on address */ if (pdie != cu_die) /* * Address filtering * The line is included in given function, and * no inline block includes it. */ if (!dwarf_haspc(pdie, addr) || die_find_inlinefunc(pdie, addr, &die_mem)) continue; /* Get source line */ fname = dwarf_linesrc(line, NULL, NULL); ret = handler(fname, lineno, addr, data); if (ret != 0) return ret; } /* * Dwarf lines doesn't include function declarations and inlined * subroutines. We have to check functions list or given function. */ if (pdie != cu_die) ret = __die_walk_funclines(pdie, handler, data); else { struct __line_walk_param param = { .handler = handler, .data = data, .retval = 0, }; dwarf_getfuncs(cu_die, __die_walk_culines_cb, ¶m, 0); ret = param.retval; } return ret; } struct __find_variable_param { const char *name; Dwarf_Addr addr; }; static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data) { struct __find_variable_param *fvp = data; int tag; tag = dwarf_tag(die_mem); if ((tag == DW_TAG_formal_parameter || tag == DW_TAG_variable) && die_compare_name(die_mem, fvp->name)) return DIE_FIND_CB_FOUND; if (dwarf_haspc(die_mem, fvp->addr)) return DIE_FIND_CB_CONTINUE; else return DIE_FIND_CB_SIBLING; } /* Find a variable called 'name' at given address */ static Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name, Dwarf_Addr addr, Dwarf_Die *die_mem) { struct __find_variable_param fvp = { .name = name, .addr = addr}; return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp, die_mem); } static int __die_find_member_cb(Dwarf_Die *die_mem, void *data) { const char *name = data; if ((dwarf_tag(die_mem) == DW_TAG_member) && die_compare_name(die_mem, name)) return DIE_FIND_CB_FOUND; return DIE_FIND_CB_SIBLING; } /* Find a member called 'name' */ static Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name, Dwarf_Die *die_mem) { return die_find_child(st_die, __die_find_member_cb, (void *)name, die_mem); } /* Get the name of given variable DIE */ static int die_get_typename(Dwarf_Die *vr_die, char *buf, int len) { Dwarf_Die type; int tag, ret, ret2; const char *tmp = ""; if (__die_get_real_type(vr_die, &type) == NULL) return -ENOENT; tag = dwarf_tag(&type); if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type) tmp = "*"; else if (tag == DW_TAG_subroutine_type) { /* Function pointer */ ret = snprintf(buf, len, "(function_type)"); return (ret >= len) ? -E2BIG : ret; } else { if (!dwarf_diename(&type)) return -ENOENT; if (tag == DW_TAG_union_type) tmp = "union "; else if (tag == DW_TAG_structure_type) tmp = "struct "; /* Write a base name */ ret = snprintf(buf, len, "%s%s", tmp, dwarf_diename(&type)); return (ret >= len) ? -E2BIG : ret; } ret = die_get_typename(&type, buf, len); if (ret > 0) { ret2 = snprintf(buf + ret, len - ret, "%s", tmp); ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret; } return ret; } /* Get the name and type of given variable DIE, stored as "type\tname" */ static int die_get_varname(Dwarf_Die *vr_die, char *buf, int len) { int ret, ret2; ret = die_get_typename(vr_die, buf, len); if (ret < 0) { pr_debug("Failed to get type, make it unknown.\n"); ret = snprintf(buf, len, "(unknown_type)"); } if (ret > 0) { ret2 = snprintf(buf + ret, len - ret, "\t%s", dwarf_diename(vr_die)); ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret; } return ret; } /* * 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. */ static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr, Dwarf_Op *fb_ops, struct probe_trace_arg *tvar) { Dwarf_Attribute attr; Dwarf_Op *op; size_t nops; unsigned int regn; Dwarf_Word offs = 0; bool ref = false; const char *regs; int ret; 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 || dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0 || nops == 0) { /* TODO: Support const_value */ return -ENOENT; } if (op->atom == DW_OP_addr) { static_var: if (!tvar) return 0; /* 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 0; } /* 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 0; regs = get_arch_regstr(regn); 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 -ERANGE; } 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 0; } #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]; int ret; /* TODO: check all types */ if (cast && strcmp(cast, "string") != 0) { /* Non string type is OK */ tvar->type = strdup(cast); return (tvar->type == NULL) ? -ENOMEM : 0; } if (die_get_bit_size(vr_die) != 0) { /* This is a bitfield */ ret = snprintf(buf, 16, "b%d@%d/%zd", die_get_bit_size(vr_die), die_get_bit_offset(vr_die), BYTES_TO_BITS(die_get_byte_size(vr_die))); 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 (ret == DW_TAG_pointer_type) { if (die_get_real_type(&type, &type) == NULL) { pr_warning("Failed to get a type" " information.\n"); return -ENOENT; } 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; } ret = BYTES_TO_BITS(die_get_byte_size(&type)); if (!ret) /* No size ... try to use default type */ return 0; /* 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", die_is_signed_type(&type) ? 's' : 'u', ret); formatted: if (ret < 0 || ret >= 16) { if (ret >= 16) ret = -E2BIG; pr_warning("Failed to convert variable type: %s\n", strerror(-ret)); 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 += die_get_byte_size(&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 */ if (dwarf_tag(&type) != DW_TAG_structure_type) { pr_warning("%s is not a data structure.\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) { pr_warning("%s is not a data structure.\n", varname); return -EINVAL; } if (field->name[0] == '[') { pr_err("Semantic error: %s is not a pointor" " nor array.\n", varname); return -EINVAL; } if (field->ref) { 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(tyep:%s) has no member %s.\n", varname, dwarf_diename(&type), field->name); return -EINVAL; } /* Get the offset of the field */ 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; 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->tvar); if (ret == -ENOENT) pr_err("Failed to find the location of %s at this address.\n" " Perhaps, it has been optimized out.\n", pf->pvar->var); else if (ret == -ENOTSUP) pr_err("Sorry, we don't support this variable location yet.\n"); else if (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 subprogram die */ static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf) { Dwarf_Die vr_die, *scopes; char buf[32], *ptr; int ret, nscopes; if (!is_c_varname(pf->pvar->var)) { /* Copy raw parameters */ pf->tvar->value = strdup(pf->pvar->var); if (pf->tvar->value == NULL) return -ENOMEM; if (pf->pvar->type) { pf->tvar->type = strdup(pf->pvar->type); if (pf->tvar->type == NULL) return -ENOMEM; } if (pf->pvar->name) { pf->tvar->name = strdup(pf->pvar->name); if (pf->tvar->name == NULL) return -ENOMEM; } else pf->tvar->name = NULL; return 0; } if (pf->pvar->name) pf->tvar->name = strdup(pf->pvar->name); else { ret = synthesize_perf_probe_arg(pf->pvar, buf, 32); if (ret < 0) return ret; ptr = strchr(buf, ':'); /* Change type separator to _ */ if (ptr) *ptr = '_'; pf->tvar->name = strdup(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(sp_die, pf->pvar->var, pf->addr, &vr_die)) ret = convert_variable(&vr_die, pf); else { /* Search upper class */ nscopes = dwarf_getscopes_die(sp_die, &scopes); while (nscopes-- > 1) { pr_debug("Searching variables in %s\n", dwarf_diename(&scopes[nscopes])); /* We should check this scope, so give dummy address */ if (die_find_variable_at(&scopes[nscopes], pf->pvar->var, 0, &vr_die)) { ret = convert_variable(&vr_die, pf); goto found; } } if (scopes) free(scopes); ret = -ENOENT; } found: if (ret < 0) pr_warning("Failed to find '%s' in this function.\n", pf->pvar->var); return ret; } /* Convert subprogram DIE to trace point */ static int convert_to_trace_point(Dwarf_Die *sp_die, Dwarf_Addr paddr, bool retprobe, struct probe_trace_point *tp) { Dwarf_Addr eaddr; const char *name; /* Copy the name of probe point */ name = dwarf_diename(sp_die); if (name) { if (dwarf_entrypc(sp_die, &eaddr) != 0) { pr_warning("Failed to get entry address of %s\n", dwarf_diename(sp_die)); return -ENOENT; } tp->symbol = strdup(name); if (tp->symbol == NULL) return -ENOMEM; tp->offset = (unsigned long)(paddr - eaddr); } else /* This function has no name. */ tp->offset = (unsigned long)paddr; /* Return probe must be on the head of a subprogram */ if (retprobe) { if (eaddr != paddr) { pr_warning("Return probe must be on the head of" " a real function.\n"); return -EINVAL; } tp->retprobe = true; } return 0; } /* Call probe_finder callback with real subprogram DIE */ static int call_probe_finder(Dwarf_Die *sp_die, struct probe_finder *pf) { Dwarf_Die die_mem; Dwarf_Attribute fb_attr; size_t nops; int ret; /* If no real subprogram, find a real one */ if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) { sp_die = die_find_real_subprogram(&pf->cu_die, pf->addr, &die_mem); if (!sp_die) { pr_warning("Failed to find probe point in any " "functions.\n"); return -ENOENT; } } /* Get the frame base attribute/ops */ dwarf_attr(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 != NULL) { Dwarf_Frame *frame; if (dwarf_cfi_addrframe(pf->cfi, 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); return -ENOENT; } #endif } /* Call finder's callback handler */ ret = pf->callback(sp_die, pf); /* *pf->fb_ops will be cached in libdw. Don't free it. */ pf->fb_ops = NULL; return ret; } static int probe_point_line_walker(const char *fname, int lineno, Dwarf_Addr addr, void *data) { struct probe_finder *pf = data; int ret; if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0) return 0; pf->addr = addr; ret = call_probe_finder(NULL, 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 list_head *head, const char *fname, const char *pat) { FILE *fp; char *line = NULL; size_t line_len; ssize_t len; int count = 0, linenum = 1; fp = fopen(fname, "r"); if (!fp) { pr_warning("Failed to open %s: %s\n", fname, strerror(errno)); return -errno; } while ((len = getline(&line, &line_len, fp)) > 0) { if (line[len - 1] == '\n') line[len - 1] = '\0'; if (strlazymatch(line, pat)) { line_list__add_line(head, 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; int ret; if (!line_list__has_line(&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; ret = call_probe_finder(NULL, 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; if (list_empty(&pf->lcache)) { /* Matching lazy line pattern */ ret = find_lazy_match_lines(&pf->lcache, pf->fname, pf->pev->point.lazy_line); if (ret <= 0) return ret; } return die_walk_lines(sp_die, probe_point_lazy_walker, pf); } /* Callback parameter with return value */ struct dwarf_callback_param { void *data; int retval; }; static int probe_point_inline_cb(Dwarf_Die *in_die, void *data) { struct dwarf_callback_param *param = data; struct probe_finder *pf = param->data; struct perf_probe_point *pp = &pf->pev->point; Dwarf_Addr addr; if (pp->lazy_line) param->retval = 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)); param->retval = -ENOENT; return DWARF_CB_ABORT; } pf->addr = addr; pf->addr += pp->offset; pr_debug("found inline addr: 0x%jx\n", (uintmax_t)pf->addr); param->retval = call_probe_finder(in_die, pf); if (param->retval < 0) return DWARF_CB_ABORT; } return DWARF_CB_OK; } /* 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 (dwarf_tag(sp_die) != DW_TAG_subprogram || !die_compare_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; 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 (!dwarf_func_inline(sp_die)) { /* Real function */ if (pp->lazy_line) param->retval = find_probe_point_lazy(sp_die, pf); else { if (dwarf_entrypc(sp_die, &pf->addr) != 0) { pr_warning("Failed to get entry address of " "%s.\n", dwarf_diename(sp_die)); param->retval = -ENOENT; return DWARF_CB_ABORT; } pf->addr += pp->offset; /* TODO: Check the address in this function */ param->retval = call_probe_finder(sp_die, pf); } } else { struct dwarf_callback_param _param = {.data = (void *)pf, .retval = 0}; /* Inlined function: search instances */ dwarf_func_inline_instances(sp_die, probe_point_inline_cb, &_param); param->retval = _param.retval; } 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; } /* Find probe points from debuginfo */ static int find_probes(int fd, struct probe_finder *pf) { struct perf_probe_point *pp = &pf->pev->point; Dwarf_Off off, noff; size_t cuhl; Dwarf_Die *diep; Dwarf *dbg = NULL; Dwfl *dwfl; Dwarf_Addr bias; /* Currently ignored */ int ret = 0; dbg = dwfl_init_offline_dwarf(fd, &dwfl, &bias); if (!dbg) { pr_warning("No debug information found in the vmlinux - " "please rebuild with CONFIG_DEBUG_INFO=y.\n"); close(fd); /* Without dwfl_end(), fd isn't closed. */ return -EBADF; } #if _ELFUTILS_PREREQ(0, 142) /* Get the call frame information from this dwarf */ pf->cfi = dwarf_getcfi(dbg); #endif off = 0; line_list__init(&pf->lcache); /* Loop on CUs (Compilation Unit) */ while (!dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL)) { /* Get the DIE(Debugging Information Entry) of this CU */ diep = dwarf_offdie(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(NULL, pf); else { pf->lno = pp->line; ret = find_probe_point_by_line(pf); } if (ret < 0) break; } off = noff; } line_list__free(&pf->lcache); if (dwfl) dwfl_end(dwfl); return ret; } /* Add a found probe point into trace event list */ static int add_probe_trace_event(Dwarf_Die *sp_die, struct probe_finder *pf) { struct trace_event_finder *tf = container_of(pf, struct trace_event_finder, pf); struct probe_trace_event *tev; 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++]; ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe, &tev->point); if (ret < 0) return ret; pr_debug("Probe point found: %s+%lu\n", tev->point.symbol, tev->point.offset); /* Find each argument */ tev->nargs = pf->pev->nargs; tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs); if (tev->args == NULL) return -ENOMEM; for (i = 0; i < pf->pev->nargs; i++) { pf->pvar = &pf->pev->args[i]; pf->tvar = &tev->args[i]; ret = find_variable(sp_die, pf); if (ret != 0) return ret; } return 0; } /* Find probe_trace_events specified by perf_probe_event from debuginfo */ int find_probe_trace_events(int fd, struct perf_probe_event *pev, struct probe_trace_event **tevs, int max_tevs) { struct trace_event_finder tf = { .pf = {.pev = pev, .callback = add_probe_trace_event}, .max_tevs = max_tevs}; int ret; /* Allocate result tevs array */ *tevs = zalloc(sizeof(struct probe_trace_event) * max_tevs); if (*tevs == NULL) return -ENOMEM; tf.tevs = *tevs; tf.ntevs = 0; ret = find_probes(fd, &tf.pf); if (ret < 0) { free(*tevs); *tevs = NULL; return ret; } return (ret < 0) ? ret : tf.ntevs; } #define MAX_VAR_LEN 64 /* 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; char buf[MAX_VAR_LEN]; 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, NULL); if (ret == 0) { ret = die_get_varname(die_mem, buf, MAX_VAR_LEN); pr_debug2("Add new var: %s\n", buf); if (ret > 0) strlist__add(vl->vars, buf); } } if (af->child && dwarf_haspc(die_mem, af->pf.addr)) return DIE_FIND_CB_CONTINUE; else return DIE_FIND_CB_SIBLING; } /* Add a found vars into available variables list */ static int add_available_vars(Dwarf_Die *sp_die, struct probe_finder *pf) { struct available_var_finder *af = container_of(pf, struct available_var_finder, pf); struct variable_list *vl; Dwarf_Die die_mem, *scopes = NULL; int ret, nscopes; /* 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++]; ret = convert_to_trace_point(sp_die, pf->addr, pf->pev->point.retprobe, &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(true, NULL); if (vl->vars == NULL) return -ENOMEM; af->child = true; die_find_child(sp_die, collect_variables_cb, (void *)af, &die_mem); /* Find external variables */ if (!af->externs) goto out; /* Don't need to search child DIE for externs. */ af->child = false; nscopes = dwarf_getscopes_die(sp_die, &scopes); while (nscopes-- > 1) die_find_child(&scopes[nscopes], collect_variables_cb, (void *)af, &die_mem); if (scopes) free(scopes); out: if (strlist__empty(vl->vars)) { strlist__delete(vl->vars); vl->vars = NULL; } return ret; } /* Find available variables at given probe point */ int find_available_vars_at(int fd, struct perf_probe_event *pev, struct variable_list **vls, int max_vls, bool externs) { struct available_var_finder af = { .pf = {.pev = pev, .callback = add_available_vars}, .max_vls = max_vls, .externs = externs}; int ret; /* Allocate result vls array */ *vls = zalloc(sizeof(struct variable_list) * max_vls); if (*vls == NULL) return -ENOMEM; af.vls = *vls; af.nvls = 0; ret = find_probes(fd, &af.pf); if (ret < 0) { /* Free vlist for error */ while (af.nvls--) { if (af.vls[af.nvls].point.symbol) free(af.vls[af.nvls].point.symbol); if (af.vls[af.nvls].vars) strlist__delete(af.vls[af.nvls].vars); } free(af.vls); *vls = NULL; return ret; } return (ret < 0) ? ret : af.nvls; } /* Reverse search */ int find_perf_probe_point(unsigned long addr, struct perf_probe_point *ppt) { Dwarf_Die cudie, spdie, indie; Dwarf *dbg = NULL; Dwfl *dwfl = NULL; Dwarf_Addr _addr, baseaddr, bias = 0; const char *fname = NULL, *func = NULL, *tmp; int baseline = 0, lineno = 0, ret = 0; /* Open the live linux kernel */ dbg = dwfl_init_live_kernel_dwarf(addr, &dwfl, &bias); if (!dbg) { pr_warning("No debug information found in the vmlinux - " "please rebuild with CONFIG_DEBUG_INFO=y.\n"); ret = -EINVAL; goto end; } /* Adjust address with bias */ addr += bias; /* Find cu die */ if (!dwarf_addrdie(dbg, (Dwarf_Addr)addr - bias, &cudie)) { 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_real_subprogram(&cudie, (Dwarf_Addr)addr, &spdie)) { /* Get function entry information */ tmp = dwarf_diename(&spdie); if (!tmp || dwarf_entrypc(&spdie, &baseaddr) != 0 || dwarf_decl_line(&spdie, &baseline) != 0) goto post; func = tmp; if (addr == (unsigned long)baseaddr) /* Function entry - Relative line number is 0 */ lineno = baseline; else if (die_find_inlinefunc(&spdie, (Dwarf_Addr)addr, &indie)) { 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. */ lineno = die_get_call_lineno(&indie); 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(&spdie, &baseline) == 0) func = tmp; } } } post: /* Make a relative line number or an offset */ if (lineno) ppt->line = lineno - baseline; else if (func) ppt->offset = addr - (unsigned long)baseaddr; /* 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) { if (ppt->function) { free(ppt->function); ppt->function = NULL; } ret = -ENOMEM; goto end; } } end: if (dwfl) dwfl_end(dwfl); 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 line_list__add_line(&lr->line_list, lineno); } static int line_range_walk_cb(const char *fname, int lineno, Dwarf_Addr addr __used, void *data) { struct line_finder *lf = data; if ((strtailcmp(fname, lf->fname) != 0) || (lf->lno_s > lineno || lf->lno_e < lineno)) return 0; if (line_range_add_line(fname, lineno, lf->lr) < 0) return -EINVAL; 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 (!list_empty(&lf->lr->line_list)) ret = lf->found = 1; else ret = 0; /* Lines are not found */ else { free(lf->lr->path); lf->lr->path = NULL; } return ret; } static int line_range_inline_cb(Dwarf_Die *in_die, void *data) { struct dwarf_callback_param *param = data; param->retval = find_line_range_by_line(in_die, param->data); return DWARF_CB_ABORT; /* No need to find other instances */ } /* Search function 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 (dwarf_tag(sp_die) == DW_TAG_subprogram && die_compare_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 (dwarf_func_inline(sp_die)) { struct dwarf_callback_param _param; _param.data = (void *)lf; _param.retval = 0; dwarf_func_inline_instances(sp_die, line_range_inline_cb, &_param); param->retval = _param.retval; } 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 find_line_range(int fd, 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; Dwarf *dbg = NULL; Dwfl *dwfl; Dwarf_Addr bias; /* Currently ignored */ const char *comp_dir; dbg = dwfl_init_offline_dwarf(fd, &dwfl, &bias); if (!dbg) { pr_warning("No debug information found in the vmlinux - " "please rebuild with CONFIG_DEBUG_INFO=y.\n"); close(fd); /* Without dwfl_end(), fd isn't closed. */ return -EBADF; } /* Loop on CUs (Compilation Unit) */ while (!lf.found && ret >= 0) { if (dwarf_nextcu(dbg, off, &noff, &cuhl, NULL, NULL, NULL) != 0) break; /* Get the DIE(Debugging Information Entry) of this CU */ diep = dwarf_offdie(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; } /* 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); dwfl_end(dwfl); return (ret < 0) ? ret : lf.found; }