diff options
Diffstat (limited to '')
| -rw-r--r-- | tools/perf/util/probe-finder.c | 2088 |
1 files changed, 2088 insertions, 0 deletions
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c new file mode 100644 index 000000000..fdafbfcef --- /dev/null +++ b/tools/perf/util/probe-finder.c @@ -0,0 +1,2088 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * probe-finder.c : C expression to kprobe event converter + * + * Written by Masami Hiramatsu <mhiramat@redhat.com> + */ + +#include <inttypes.h> +#include <sys/utsname.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <errno.h> +#include <stdio.h> +#include <unistd.h> +#include <stdlib.h> +#include <string.h> +#include <stdarg.h> +#include <dwarf-regs.h> + +#include <linux/bitops.h> +#include <linux/zalloc.h> +#include "event.h" +#include "dso.h" +#include "debug.h" +#include "intlist.h" +#include "strbuf.h" +#include "strlist.h" +#include "symbol.h" +#include "probe-finder.h" +#include "probe-file.h" +#include "string2.h" + +#ifdef HAVE_DEBUGINFOD_SUPPORT +#include <elfutils/debuginfod.h> +#endif + +/* 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) +{ + GElf_Addr dummy; + 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_module_build_id(dbg->mod, &dbg->build_id, &dummy); + + 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__MIXEDUP_UBUNTU_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; + + /* Constant value */ + if (dwarf_attr(vr_die, DW_AT_const_value, &attr) && + immediate_value_is_supported()) { + Dwarf_Sword snum; + + if (!tvar) + return 0; + + dwarf_formsdata(&attr, &snum); + ret = asprintf(&tvar->value, "\\%ld", (long)snum); + + return ret < 0 ? -ENOMEM : 0; + } + + /* 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, bool user_access) +{ + 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, "ustring") && + 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") || !strcmp(cast, "ustring"))) { + /* 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; + } + (*ref_ptr)->user_access = user_access; + } + 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, bool user_access) +{ + 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: %s (%x)\n", dwarf_diename(&type), + (unsigned)dwarf_dieoffset(&type)); + tag = dwarf_tag(&type); + + if (field->name[0] == '[' && + (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) { + /* Save original type for next field or type */ + 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: %s (%x)\n", dwarf_diename(&type), + (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; + ref->user_access = user_access; + 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 a 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 a 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; + ref->user_access = user_access; + + /* 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, user_access); + +next: + /* Converting next field */ + if (field->next) + return convert_variable_fields(die_mem, field->name, + field->next, &ref, die_mem, user_access); + else + return 0; +} + +static void print_var_not_found(const char *varname) +{ + 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", + varname, varname); +} + +/* 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 && pf->skip_empty_arg) + /* This can be found in other place. skip it */ + return 0; + if (ret == -ENOENT || ret == -EINVAL) { + print_var_not_found(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, pf->pvar->user_access); + vr_die = &die_mem; + } + if (ret == 0) + ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type, + pf->pvar->user_access); + /* *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)) { + if (pf->skip_empty_arg) + return 0; + 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; + GElf_Sym sym; + const char *symbol; + + /* Verify the address is correct */ + if (!dwarf_haspc(sp_die, paddr)) { + pr_warning("Specified offset is out of %s\n", + dwarf_diename(sp_die)); + return -EINVAL; + } + + if (dwarf_entrypc(sp_die, &eaddr) == 0) { + /* If the DIE has entrypc, use it. */ + symbol = dwarf_diename(sp_die); + } else { + /* Try to get actual symbol name and address from symtab */ + symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL); + eaddr = sym.st_value; + } + if (!symbol) { + pr_warning("Failed to find symbol at 0x%lx\n", + (unsigned long)paddr); + return -ENOENT; + } + + 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; +} + +/* Return innermost DIE */ +static int find_inner_scope_cb(Dwarf_Die *fn_die, void *data) +{ + struct find_scope_param *fsp = data; + + memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die)); + fsp->found = true; + return 1; +} + +/* 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, + }; + int ret; + + ret = cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, + &fsp); + if (!ret && !fsp.found) + cu_walk_functions_at(&pf->cu_die, pf->addr, + find_inner_scope_cb, &fsp); + + return fsp.found ? die_mem : NULL; +} + +static int verify_representive_line(struct probe_finder *pf, const char *fname, + int lineno, Dwarf_Addr addr) +{ + const char *__fname, *__func = NULL; + Dwarf_Die die_mem; + int __lineno; + + /* Verify line number and address by reverse search */ + if (cu_find_lineinfo(&pf->cu_die, addr, &__fname, &__lineno) < 0) + return 0; + + pr_debug2("Reversed line: %s:%d\n", __fname, __lineno); + if (strcmp(fname, __fname) || lineno == __lineno) + return 0; + + pr_warning("This line is sharing the address with other lines.\n"); + + if (pf->pev->point.function) { + /* Find best match function name and lines */ + pf->addr = addr; + if (find_best_scope(pf, &die_mem) + && die_match_name(&die_mem, pf->pev->point.function) + && dwarf_decl_line(&die_mem, &lineno) == 0) { + __func = dwarf_diename(&die_mem); + __lineno -= lineno; + } + } + pr_warning("Please try to probe at %s:%d instead.\n", + __func ? : __fname, __lineno); + + return -ENOENT; +} + +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; + + if (verify_representive_line(pf, fname, lineno, addr)) + return -ENOENT; + + 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) +{ + struct build_id bid; + char sbuild_id[SBUILD_ID_SIZE] = ""; + int ret = 0; + char *fpath; + + if (intlist__empty(pf->lcache)) { + const char *comp_dir; + + comp_dir = cu_get_comp_dir(&pf->cu_die); + if (pf->dbg->build_id) { + build_id__init(&bid, pf->dbg->build_id, BUILD_ID_SIZE); + build_id__sprintf(&bid, sbuild_id); + } + ret = find_source_path(pf->fname, sbuild_id, 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 (die_entrypc(in_die, &addr) != 0) { + pr_warning("Failed to get entry address of %s.\n", + dwarf_diename(in_die)); + return -ENOENT; + } + if (addr == 0) { + pr_debug("%s has no valid entry address. skipped.\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 */ + die_entrypc(sp_die, &pf->addr); + /* But in some case the entry address is 0 */ + if (pf->addr == 0) { + pr_debug("%s has no entry PC. Skipped\n", + dwarf_diename(sp_die)); + param->retval = 0; + /* Real function */ + } else 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; +} + +static bool trace_event_finder_overlap(struct trace_event_finder *tf) +{ + int i; + + for (i = 0; i < tf->ntevs; i++) { + if (tf->pf.addr == tf->tevs[i].point.address) + return true; + } + return false; +} + +/* 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; + + /* + * For some reason (e.g. different column assigned to same address) + * This callback can be called with the address which already passed. + * Ignore it first. + */ + if (trace_event_finder_overlap(tf)) + return 0; + + /* 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; +} + +static int fill_empty_trace_arg(struct perf_probe_event *pev, + struct probe_trace_event *tevs, int ntevs) +{ + char **valp; + char *type; + int i, j, ret; + + if (!ntevs) + return -ENOENT; + + for (i = 0; i < pev->nargs; i++) { + type = NULL; + for (j = 0; j < ntevs; j++) { + if (tevs[j].args[i].value) { + type = tevs[j].args[i].type; + break; + } + } + if (j == ntevs) { + print_var_not_found(pev->args[i].var); + return -ENOENT; + } + for (j = 0; j < ntevs; j++) { + valp = &tevs[j].args[i].value; + if (*valp) + continue; + + ret = asprintf(valp, "\\%lx", probe_conf.magic_num); + if (ret < 0) + return -ENOMEM; + /* Note that type can be NULL */ + if (type) { + tevs[j].args[i].type = strdup(type); + if (!tevs[j].args[i].type) + return -ENOMEM; + } + } + } + return 0; +} + +/* 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, .dbg = dbg, .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; + + if (pev->nargs != 0 && immediate_value_is_supported()) + tf.pf.skip_empty_arg = true; + + ret = debuginfo__find_probes(dbg, &tf.pf); + if (ret >= 0 && tf.pf.skip_empty_arg) + ret = fill_empty_trace_arg(pev, tf.tevs, tf.ntevs); + + if (ret < 0 || tf.ntevs == 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; +} + +static bool available_var_finder_overlap(struct available_var_finder *af) +{ + int i; + + for (i = 0; i < af->nvls; i++) { + if (af->pf.addr == af->vls[i].point.address) + return true; + } + return false; + +} + +/* 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; + + /* + * For some reason (e.g. different column assigned to same address), + * this callback can be called with the address which already passed. + * Ignore it first. + */ + if (available_var_finder_overlap(af)) + return 0; + + /* 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, .dbg = dbg, .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 */ +int debuginfo__get_text_offset(struct debuginfo *dbg, Dwarf_Addr *offs, + bool adjust_offset) +{ + 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; + if (adjust_offset) + *offs -= shdr->sh_offset; + } + } + 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; + + /* We always need to relocate the address for aranges */ + if (debuginfo__get_text_offset(dbg, &baseaddr, false) == 0) + addr += baseaddr; + /* Find cu die */ + if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &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_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) { + /* Get function entry information */ + func = basefunc = dwarf_diename(&spdie); + if (!func || + die_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 (die_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; + const char *__fname; + int __lineno; + int err; + + if ((strtailcmp(fname, lf->fname) != 0) || + (lf->lno_s > lineno || lf->lno_e < lineno)) + return 0; + + /* Make sure this line can be reversable */ + if (cu_find_lineinfo(&lf->cu_die, addr, &__fname, &__lineno) > 0 + && (lineno != __lineno || strcmp(fname, __fname))) + 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_match_name(sp_die, lr->function) && die_is_func_def(sp_die)) { + 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; +} + +#ifdef HAVE_DEBUGINFOD_SUPPORT +/* debuginfod doesn't require the comp_dir but buildid is required */ +static int get_source_from_debuginfod(const char *raw_path, + const char *sbuild_id, char **new_path) +{ + debuginfod_client *c = debuginfod_begin(); + const char *p = raw_path; + int fd; + + if (!c) + return -ENOMEM; + + fd = debuginfod_find_source(c, (const unsigned char *)sbuild_id, + 0, p, new_path); + pr_debug("Search %s from debuginfod -> %d\n", p, fd); + if (fd >= 0) + close(fd); + debuginfod_end(c); + if (fd < 0) { + pr_debug("Failed to find %s in debuginfod (%s)\n", + raw_path, sbuild_id); + return -ENOENT; + } + pr_debug("Got a source %s\n", *new_path); + + return 0; +} +#else +static inline int get_source_from_debuginfod(const char *raw_path __maybe_unused, + const char *sbuild_id __maybe_unused, + char **new_path __maybe_unused) +{ + return -ENOTSUP; +} +#endif +/* + * 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 find_source_path(const char *raw_path, const char *sbuild_id, + const char *comp_dir, char **new_path) +{ + const char *prefix = symbol_conf.source_prefix; + + if (sbuild_id && !prefix) { + if (!get_source_from_debuginfod(raw_path, sbuild_id, new_path)) + return 0; + } + + 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; + } + } +} |