[mirror_ubuntu-bionic-kernel.git] / tools / perf / util / probe-finder.c

/*
 * probe-finder.c : C expression to kprobe event converter
 *
 * Written by Masami Hiramatsu <mhiramat@redhat.com>
 *
 * 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 <sys/utsname.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <getopt.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <ctype.h>
#include <dwarf-regs.h>

#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 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);

        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 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,
};

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 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;
}

/* 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) {
                dwfl_end(*dwflp);
                *dwflp = NULL;
        }
        return dbg;
}

/* 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);
}

/* 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 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 bool die_is_signed_type(Dwarf_Die *tp_die)
{
        Dwarf_Attribute attr;
        Dwarf_Word ret;

        if (dwarf_attr(tp_die, DW_AT_encoding, &attr) == NULL ||
            dwarf_formudata(&attr, &ret) != 0)
                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_Attribute attr;
        Dwarf_Word ret;

        if (dwarf_attr(tp_die, DW_AT_byte_size, &attr) == NULL ||
            dwarf_formudata(&attr, &ret) != 0)
                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)
{
        return die_find_child(sp_die, __die_find_inline_cb, &addr, die_mem);
}

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 DWARF register number %u "
                           "missing on this architecture.", 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;
}

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_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.",
                                   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.");
                                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 *.",
                                   dwarf_diename(vr_die));
                        return -EINVAL;
                }
                tvar->type = strdup(cast);
                return (tvar->type == NULL) ? -ENOMEM : 0;
        }

        ret = die_get_byte_size(&type) * 8;
        if (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",
                               die_is_signed_type(&type) ? 's' : 'u', ret);
                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.",
                               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 pc 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 CFA 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;
}

/* Find probe point from its line number */
static int find_probe_point_by_line(struct probe_finder *pf)
{
        Dwarf_Lines *lines;
        Dwarf_Line *line;
        size_t nlines, i;
        Dwarf_Addr addr;
        int lineno;
        int ret = 0;

        if (dwarf_getsrclines(&pf->cu_die, &lines, &nlines) != 0) {
                pr_warning("No source lines found in this CU.\n");
                return -ENOENT;
        }

        for (i = 0; i < nlines && ret == 0; i++) {
                line = dwarf_onesrcline(lines, i);
                if (dwarf_lineno(line, &lineno) != 0 ||
                    lineno != pf->lno)
                        continue;

                /* TODO: Get fileno from line, but how? */
                if (strtailcmp(dwarf_linesrc(line, NULL, NULL), pf->fname) != 0)
                        continue;

                if (dwarf_lineaddr(line, &addr) != 0) {
                        pr_warning("Failed to get the address of the line.\n");
                        return -ENOENT;
                }
                pr_debug("Probe line found: line[%d]:%d addr:0x%jx\n",
                         (int)i, lineno, (uintmax_t)addr);
                pf->addr = addr;

                ret = call_probe_finder(NULL, pf);
                /* Continuing, because target line might be inlined. */
        }
        return ret;
}

/* Find lines which match lazy pattern */
static int find_lazy_match_lines(struct list_head *head,
                                 const char *fname, const char *pat)
{
        char *fbuf, *p1, *p2;
        int fd, line, nlines = -1;
        struct stat st;

        fd = open(fname, O_RDONLY);
        if (fd < 0) {
                pr_warning("Failed to open %s: %s\n", fname, strerror(-fd));
                return -errno;
        }

        if (fstat(fd, &st) < 0) {
                pr_warning("Failed to get the size of %s: %s\n",
                           fname, strerror(errno));
                nlines = -errno;
                goto out_close;
        }

        nlines = -ENOMEM;
        fbuf = malloc(st.st_size + 2);
        if (fbuf == NULL)
                goto out_close;
        if (read(fd, fbuf, st.st_size) < 0) {
                pr_warning("Failed to read %s: %s\n", fname, strerror(errno));
                nlines = -errno;
                goto out_free_fbuf;
        }
        fbuf[st.st_size] = '\n';        /* Dummy line */
        fbuf[st.st_size + 1] = '\0';
        p1 = fbuf;
        line = 1;
        nlines = 0;
        while ((p2 = strchr(p1, '\n')) != NULL) {
                *p2 = '\0';
                if (strlazymatch(p1, pat)) {
                        line_list__add_line(head, line);
                        nlines++;
                }
                line++;
                p1 = p2 + 1;
        }
out_free_fbuf:
        free(fbuf);
out_close:
        close(fd);
        return nlines;
}

/* Find probe points from lazy pattern  */
static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
{
        Dwarf_Lines *lines;
        Dwarf_Line *line;
        size_t nlines, i;
        Dwarf_Addr addr;
        Dwarf_Die die_mem;
        int lineno;
        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) {
                        pr_debug("No matched lines found in %s.\n", pf->fname);
                        return 0;
                } else if (ret < 0)
                        return ret;
        }

        if (dwarf_getsrclines(&pf->cu_die, &lines, &nlines) != 0) {
                pr_warning("No source lines found in this CU.\n");
                return -ENOENT;
        }

        for (i = 0; i < nlines && ret >= 0; i++) {
                line = dwarf_onesrcline(lines, i);

                if (dwarf_lineno(line, &lineno) != 0 ||
                    !line_list__has_line(&pf->lcache, lineno))
                        continue;

                /* TODO: Get fileno from line, but how? */
                if (strtailcmp(dwarf_linesrc(line, NULL, NULL), pf->fname) != 0)
                        continue;

                if (dwarf_lineaddr(line, &addr) != 0) {
                        pr_debug("Failed to get the address of line %d.\n",
                                 lineno);
                        continue;
                }
                if (sp_die) {
                        /* Address filtering 1: does sp_die include addr? */
                        if (!dwarf_haspc(sp_die, addr))
                                continue;
                        /* Address filtering 2: No child include addr? */
                        if (die_find_inlinefunc(sp_die, addr, &die_mem))
                                continue;
                }

                pr_debug("Probe line found: line[%d]:%d addr:0x%llx\n",
                         (int)i, lineno, (unsigned long long)addr);
                pf->addr = addr;

                ret = call_probe_finder(sp_die, pf);
                /* Continuing, because target line might be inlined. */
        }
        /* TODO: deallocate lines, but how? */
        return ret;
}

/* 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 pc 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;

        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 pc 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 dwarf info found in the vmlinux - "
                        "please rebuild with CONFIG_DEBUG_INFO=y.\n");
                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) &&
               ret >= 0) {
                /* 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);
                        }
                }
                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_Line *line;
        Dwarf_Addr laddr, eaddr, bias = 0;
        const char *tmp;
        int lineno, ret = 0;
        bool found = false;

        /* Open the live linux kernel */
        dbg = dwfl_init_live_kernel_dwarf(addr, &dwfl, &bias);
        if (!dbg) {
                pr_warning("No dwarf info 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("No CU DIE is found at %lx\n", addr);
                ret = -EINVAL;
                goto end;
        }

        /* Find a corresponding line */
        line = dwarf_getsrc_die(&cudie, (Dwarf_Addr)addr);
        if (line) {
                if (dwarf_lineaddr(line, &laddr) == 0 &&
                    (Dwarf_Addr)addr == laddr &&
                    dwarf_lineno(line, &lineno) == 0) {
                        tmp = dwarf_linesrc(line, NULL, NULL);
                        if (tmp) {
                                ppt->line = lineno;
                                ppt->file = strdup(tmp);
                                if (ppt->file == NULL) {
                                        ret = -ENOMEM;
                                        goto end;
                                }
                                found = true;
                        }
                }
        }

        /* Find a corresponding function */
        if (die_find_real_subprogram(&cudie, (Dwarf_Addr)addr, &spdie)) {
                tmp = dwarf_diename(&spdie);
                if (!tmp || dwarf_entrypc(&spdie, &eaddr) != 0)
                        goto end;

                if (ppt->line) {
                        if (die_find_inlinefunc(&spdie, (Dwarf_Addr)addr,
                                                &indie)) {
                                /* addr in an inline function */
                                tmp = dwarf_diename(&indie);
                                if (!tmp)
                                        goto end;
                                ret = dwarf_decl_line(&indie, &lineno);
                        } else {
                                if (eaddr == addr) {    /* Function entry */
                                        lineno = ppt->line;
                                        ret = 0;
                                } else
                                        ret = dwarf_decl_line(&spdie, &lineno);
                        }
                        if (ret == 0) {
                                /* Make a relative line number */
                                ppt->line -= lineno;
                                goto found;
                        }
                }
                /* We don't have a line number, let's use offset */
                ppt->offset = addr - (unsigned long)eaddr;
found:
                ppt->function = strdup(tmp);
                if (ppt->function == NULL) {
                        ret = -ENOMEM;
                        goto end;
                }
                found = true;
        }

end:
        if (dwfl)
                dwfl_end(dwfl);
        if (ret >= 0)
                ret = found ? 1 : 0;
        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);
}

/* Search function declaration lines */
static int line_range_funcdecl_cb(Dwarf_Die *sp_die, void *data)
{
        struct dwarf_callback_param *param = data;
        struct line_finder *lf = param->data;
        const char *src;
        int lineno;

        src = dwarf_decl_file(sp_die);
        if (src && strtailcmp(src, lf->fname) != 0)
                return DWARF_CB_OK;

        if (dwarf_decl_line(sp_die, &lineno) != 0 ||
            (lf->lno_s > lineno || lf->lno_e < lineno))
                return DWARF_CB_OK;

        param->retval = line_range_add_line(src, lineno, lf->lr);
        if (param->retval < 0)
                return DWARF_CB_ABORT;
        return DWARF_CB_OK;
}

static int find_line_range_func_decl_lines(struct line_finder *lf)
{
        struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
        dwarf_getfuncs(&lf->cu_die, line_range_funcdecl_cb, &param, 0);
        return param.retval;
}

/* Find line range from its line number */
static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
{
        Dwarf_Lines *lines;
        Dwarf_Line *line;
        size_t nlines, i;
        Dwarf_Addr addr;
        int lineno, ret = 0;
        const char *src;
        Dwarf_Die die_mem;

        line_list__init(&lf->lr->line_list);
        if (dwarf_getsrclines(&lf->cu_die, &lines, &nlines) != 0) {
                pr_warning("No source lines found in this CU.\n");
                return -ENOENT;
        }

        /* Search probable lines on lines list */
        for (i = 0; i < nlines; i++) {
                line = dwarf_onesrcline(lines, i);
                if (dwarf_lineno(line, &lineno) != 0 ||
                    (lf->lno_s > lineno || lf->lno_e < lineno))
                        continue;

                if (sp_die) {
                        /* Address filtering 1: does sp_die include addr? */
                        if (dwarf_lineaddr(line, &addr) != 0 ||
                            !dwarf_haspc(sp_die, addr))
                                continue;

                        /* Address filtering 2: No child include addr? */
                        if (die_find_inlinefunc(sp_die, addr, &die_mem))
                                continue;
                }

                /* TODO: Get fileno from line, but how? */
                src = dwarf_linesrc(line, NULL, NULL);
                if (strtailcmp(src, lf->fname) != 0)
                        continue;

                ret = line_range_add_line(src, lineno, lf->lr);
                if (ret < 0)
                        return ret;
        }

        /*
         * Dwarf lines doesn't include function declarations. We have to
         * check functions list or given function.
         */
        if (sp_die) {
                src = dwarf_decl_file(sp_die);
                if (src && dwarf_decl_line(sp_die, &lineno) == 0 &&
                    (lf->lno_s <= lineno && lf->lno_e >= lineno))
                        ret = line_range_add_line(src, lineno, lf->lr);
        } else
                ret = find_line_range_func_decl_lines(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;

        pr_debug("find (%llx) %s\n",
                 (unsigned long long)dwarf_dieoffset(sp_die),
                 dwarf_diename(sp_die));
        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, &param, 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 dwarf info found in the vmlinux - "
                        "please rebuild with CONFIG_DEBUG_INFO=y.\n");
                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;
}