symbol.c

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#include <dirent.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/param.h>
#include <fcntl.h>
#include <unistd.h>
#include <inttypes.h>
#include "build-id.h"
#include "util.h"
#include "debug.h"
#include "symbol.h"
#include "strlist.h"

#include <elf.h>
#include <limits.h>
#include <sys/utsname.h>

#ifndef KSYM_NAME_LEN
#define KSYM_NAME_LEN 256
#endif

static void dso_cache__free(struct rb_root *root);
static int dso__load_kernel_sym(struct dso *dso, struct map *map,
                symbol_filter_t filter);
static int dso__load_guest_kernel_sym(struct dso *dso, struct map *map,
            symbol_filter_t filter);
static int vmlinux_path__nr_entries;
static char **vmlinux_path;

struct symbol_conf symbol_conf = {
    .exclude_other    = true,
    .use_modules      = true,
    .try_vmlinux_path = true,
    .annotate_src     = true,
    .symfs            = "",
};

static enum dso_binary_type binary_type_symtab[] = {
    DSO_BINARY_TYPE__KALLSYMS,
    DSO_BINARY_TYPE__GUEST_KALLSYMS,
    DSO_BINARY_TYPE__JAVA_JIT,
    DSO_BINARY_TYPE__DEBUGLINK,
    DSO_BINARY_TYPE__BUILD_ID_CACHE,
    DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
    DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
    DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
    DSO_BINARY_TYPE__SYSTEM_PATH_DSO,
    DSO_BINARY_TYPE__GUEST_KMODULE,
    DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE,
    DSO_BINARY_TYPE__NOT_FOUND,
};

#define DSO_BINARY_TYPE__SYMTAB_CNT ARRAY_SIZE(binary_type_symtab)

static enum dso_binary_type binary_type_data[] = {
    DSO_BINARY_TYPE__BUILD_ID_CACHE,
    DSO_BINARY_TYPE__SYSTEM_PATH_DSO,
    DSO_BINARY_TYPE__NOT_FOUND,
};

#define DSO_BINARY_TYPE__DATA_CNT ARRAY_SIZE(binary_type_data)

int dso__name_len(const struct dso *dso)
{
    if (!dso)
        return strlen("[unknown]");
    if (verbose)
        return dso->long_name_len;

    return dso->short_name_len;
}

bool dso__loaded(const struct dso *dso, enum map_type type)
{
    return dso->loaded & (1 << type);
}

bool dso__sorted_by_name(const struct dso *dso, enum map_type type)
{
    return dso->sorted_by_name & (1 << type);
}

static void dso__set_sorted_by_name(struct dso *dso, enum map_type type)
{
    dso->sorted_by_name |= (1 << type);
}

bool symbol_type__is_a(char symbol_type, enum map_type map_type)
{
    symbol_type = toupper(symbol_type);

    switch (map_type) {
    case MAP__FUNCTION:
        return symbol_type == 'T' || symbol_type == 'W';
    case MAP__VARIABLE:
        return symbol_type == 'D';
    default:
        return false;
    }
}

static int prefix_underscores_count(const char *str)
{
    const char *tail = str;

    while (*tail == '_')
        tail++;

    return tail - str;
}

#define SYMBOL_A 0
#define SYMBOL_B 1

static int choose_best_symbol(struct symbol *syma, struct symbol *symb)
{
    s64 a;
    s64 b;

    /* Prefer a symbol with non zero length */
    a = syma->end - syma->start;
    b = symb->end - symb->start;
    if ((b == 0) && (a > 0))
        return SYMBOL_A;
    else if ((a == 0) && (b > 0))
        return SYMBOL_B;

    /* Prefer a non weak symbol over a weak one */
    a = syma->binding == STB_WEAK;
    b = symb->binding == STB_WEAK;
    if (b && !a)
        return SYMBOL_A;
    if (a && !b)
        return SYMBOL_B;

    /* Prefer a global symbol over a non global one */
    a = syma->binding == STB_GLOBAL;
    b = symb->binding == STB_GLOBAL;
    if (a && !b)
        return SYMBOL_A;
    if (b && !a)
        return SYMBOL_B;

    /* Prefer a symbol with less underscores */
    a = prefix_underscores_count(syma->name);
    b = prefix_underscores_count(symb->name);
    if (b > a)
        return SYMBOL_A;
    else if (a > b)
        return SYMBOL_B;

    /* If all else fails, choose the symbol with the longest name */
    if (strlen(syma->name) >= strlen(symb->name))
        return SYMBOL_A;
    else
        return SYMBOL_B;
}

void symbols__fixup_duplicate(struct rb_root *symbols)
{
    struct rb_node *nd;
    struct symbol *curr, *next;

    nd = rb_first(symbols);

    while (nd) {
        curr = rb_entry(nd, struct symbol, rb_node);
again:
        nd = rb_next(&curr->rb_node);
        next = rb_entry(nd, struct symbol, rb_node);

        if (!nd)
            break;

        if (curr->start != next->start)
            continue;

        if (choose_best_symbol(curr, next) == SYMBOL_A) {
            rb_erase(&next->rb_node, symbols);
            goto again;
        } else {
            nd = rb_next(&curr->rb_node);
            rb_erase(&curr->rb_node, symbols);
        }
    }
}

void symbols__fixup_end(struct rb_root *symbols)
{
    struct rb_node *nd, *prevnd = rb_first(symbols);
    struct symbol *curr, *prev;

    if (prevnd == NULL)
        return;

    curr = rb_entry(prevnd, struct symbol, rb_node);

    for (nd = rb_next(prevnd); nd; nd = rb_next(nd)) {
        prev = curr;
        curr = rb_entry(nd, struct symbol, rb_node);

        if (prev->end == prev->start && prev->end != curr->start)
            prev->end = curr->start - 1;
    }

    /* Last entry */
    if (curr->end == curr->start)
        curr->end = roundup(curr->start, 4096);
}

void __map_groups__fixup_end(struct map_groups *mg, enum map_type type)
{
    struct map *prev, *curr;
    struct rb_node *nd, *prevnd = rb_first(&mg->maps[type]);

    if (prevnd == NULL)
        return;

    curr = rb_entry(prevnd, struct map, rb_node);

    for (nd = rb_next(prevnd); nd; nd = rb_next(nd)) {
        prev = curr;
        curr = rb_entry(nd, struct map, rb_node);
        prev->end = curr->start - 1;
    }

    /*
     * We still haven't the actual symbols, so guess the
     * last map final address.
     */
    curr->end = ~0ULL;
}

static void map_groups__fixup_end(struct map_groups *mg)
{
    int i;
    for (i = 0; i < MAP__NR_TYPES; ++i)
        __map_groups__fixup_end(mg, i);
}

struct symbol *symbol__new(u64 start, u64 len, u8 binding, const char *name)
{
    size_t namelen = strlen(name) + 1;
    struct symbol *sym = calloc(1, (symbol_conf.priv_size +
                    sizeof(*sym) + namelen));
    if (sym == NULL)
        return NULL;

    if (symbol_conf.priv_size)
        sym = ((void *)sym) + symbol_conf.priv_size;

    sym->start   = start;
    sym->end     = len ? start + len - 1 : start;
    sym->binding = binding;
    sym->namelen = namelen - 1;

    pr_debug4("%s: %s %#" PRIx64 "-%#" PRIx64 "\n",
          __func__, name, start, sym->end);
    memcpy(sym->name, name, namelen);

    return sym;
}

void symbol__delete(struct symbol *sym)
{
    free(((void *)sym) - symbol_conf.priv_size);
}

static size_t symbol__fprintf(struct symbol *sym, FILE *fp)
{
    return fprintf(fp, " %" PRIx64 "-%" PRIx64 " %c %s\n",
               sym->start, sym->end,
               sym->binding == STB_GLOBAL ? 'g' :
               sym->binding == STB_LOCAL  ? 'l' : 'w',
               sym->name);
}

size_t symbol__fprintf_symname_offs(const struct symbol *sym,
                    const struct addr_location *al, FILE *fp)
{
    unsigned long offset;
    size_t length;

    if (sym && sym->name) {
        length = fprintf(fp, "%s", sym->name);
        if (al) {
            offset = al->addr - sym->start;
            length += fprintf(fp, "+0x%lx", offset);
        }
        return length;
    } else
        return fprintf(fp, "[unknown]");
}

size_t symbol__fprintf_symname(const struct symbol *sym, FILE *fp)
{
    return symbol__fprintf_symname_offs(sym, NULL, fp);
}

void dso__set_long_name(struct dso *dso, char *name)
{
    if (name == NULL)
        return;
    dso->long_name = name;
    dso->long_name_len = strlen(name);
}

static void dso__set_short_name(struct dso *dso, const char *name)
{
    if (name == NULL)
        return;
    dso->short_name = name;
    dso->short_name_len = strlen(name);
}

static void dso__set_basename(struct dso *dso)
{
    dso__set_short_name(dso, basename(dso->long_name));
}

struct dso *dso__new(const char *name)
{
    struct dso *dso = calloc(1, sizeof(*dso) + strlen(name) + 1);

    if (dso != NULL) {
        int i;
        strcpy(dso->name, name);
        dso__set_long_name(dso, dso->name);
        dso__set_short_name(dso, dso->name);
        for (i = 0; i < MAP__NR_TYPES; ++i)
            dso->symbols[i] = dso->symbol_names[i] = RB_ROOT;
        dso->cache = RB_ROOT;
        dso->symtab_type = DSO_BINARY_TYPE__NOT_FOUND;
        dso->data_type   = DSO_BINARY_TYPE__NOT_FOUND;
        dso->loaded = 0;
        dso->sorted_by_name = 0;
        dso->has_build_id = 0;
        dso->kernel = DSO_TYPE_USER;
        dso->needs_swap = DSO_SWAP__UNSET;
        INIT_LIST_HEAD(&dso->node);
    }

    return dso;
}

static void symbols__delete(struct rb_root *symbols)
{
    struct symbol *pos;
    struct rb_node *next = rb_first(symbols);

    while (next) {
        pos = rb_entry(next, struct symbol, rb_node);
        next = rb_next(&pos->rb_node);
        rb_erase(&pos->rb_node, symbols);
        symbol__delete(pos);
    }
}

void dso__delete(struct dso *dso)
{
    int i;
    for (i = 0; i < MAP__NR_TYPES; ++i)
        symbols__delete(&dso->symbols[i]);
    if (dso->sname_alloc)
        free((char *)dso->short_name);
    if (dso->lname_alloc)
        free(dso->long_name);
    dso_cache__free(&dso->cache);
    free(dso);
}

void dso__set_build_id(struct dso *dso, void *build_id)
{
    memcpy(dso->build_id, build_id, sizeof(dso->build_id));
    dso->has_build_id = 1;
}

void symbols__insert(struct rb_root *symbols, struct symbol *sym)
{
    struct rb_node **p = &symbols->rb_node;
    struct rb_node *parent = NULL;
    const u64 ip = sym->start;
    struct symbol *s;

    while (*p != NULL) {
        parent = *p;
        s = rb_entry(parent, struct symbol, rb_node);
        if (ip < s->start)
            p = &(*p)->rb_left;
        else
            p = &(*p)->rb_right;
    }
    rb_link_node(&sym->rb_node, parent, p);
    rb_insert_color(&sym->rb_node, symbols);
}

static struct symbol *symbols__find(struct rb_root *symbols, u64 ip)
{
    struct rb_node *n;

    if (symbols == NULL)
        return NULL;

    n = symbols->rb_node;

    while (n) {
        struct symbol *s = rb_entry(n, struct symbol, rb_node);

        if (ip < s->start)
            n = n->rb_left;
        else if (ip > s->end)
            n = n->rb_right;
        else
            return s;
    }

    return NULL;
}

struct symbol_name_rb_node {
    struct rb_node  rb_node;
    struct symbol   sym;
};

static void symbols__insert_by_name(struct rb_root *symbols, struct symbol *sym)
{
    struct rb_node **p = &symbols->rb_node;
    struct rb_node *parent = NULL;
    struct symbol_name_rb_node *symn, *s;

    symn = container_of(sym, struct symbol_name_rb_node, sym);

    while (*p != NULL) {
        parent = *p;
        s = rb_entry(parent, struct symbol_name_rb_node, rb_node);
        if (strcmp(sym->name, s->sym.name) < 0)
            p = &(*p)->rb_left;
        else
            p = &(*p)->rb_right;
    }
    rb_link_node(&symn->rb_node, parent, p);
    rb_insert_color(&symn->rb_node, symbols);
}

static void symbols__sort_by_name(struct rb_root *symbols,
                  struct rb_root *source)
{
    struct rb_node *nd;

    for (nd = rb_first(source); nd; nd = rb_next(nd)) {
        struct symbol *pos = rb_entry(nd, struct symbol, rb_node);
        symbols__insert_by_name(symbols, pos);
    }
}

static struct symbol *symbols__find_by_name(struct rb_root *symbols,
                        const char *name)
{
    struct rb_node *n;

    if (symbols == NULL)
        return NULL;

    n = symbols->rb_node;

    while (n) {
        struct symbol_name_rb_node *s;
        int cmp;

        s = rb_entry(n, struct symbol_name_rb_node, rb_node);
        cmp = strcmp(name, s->sym.name);

        if (cmp < 0)
            n = n->rb_left;
        else if (cmp > 0)
            n = n->rb_right;
        else
            return &s->sym;
    }

    return NULL;
}

struct symbol *dso__find_symbol(struct dso *dso,
                enum map_type type, u64 addr)
{
    return symbols__find(&dso->symbols[type], addr);
}

struct symbol *dso__find_symbol_by_name(struct dso *dso, enum map_type type,
                    const char *name)
{
    return symbols__find_by_name(&dso->symbol_names[type], name);
}

void dso__sort_by_name(struct dso *dso, enum map_type type)
{
    dso__set_sorted_by_name(dso, type);
    return symbols__sort_by_name(&dso->symbol_names[type],
                     &dso->symbols[type]);
}

int build_id__sprintf(const u8 *build_id, int len, char *bf)
{
    char *bid = bf;
    const u8 *raw = build_id;
    int i;

    for (i = 0; i < len; ++i) {
        sprintf(bid, "%02x", *raw);
        ++raw;
        bid += 2;
    }

    return raw - build_id;
}

size_t dso__fprintf_buildid(struct dso *dso, FILE *fp)
{
    char sbuild_id[BUILD_ID_SIZE * 2 + 1];

    build_id__sprintf(dso->build_id, sizeof(dso->build_id), sbuild_id);
    return fprintf(fp, "%s", sbuild_id);
}

size_t dso__fprintf_symbols_by_name(struct dso *dso,
                    enum map_type type, FILE *fp)
{
    size_t ret = 0;
    struct rb_node *nd;
    struct symbol_name_rb_node *pos;

    for (nd = rb_first(&dso->symbol_names[type]); nd; nd = rb_next(nd)) {
        pos = rb_entry(nd, struct symbol_name_rb_node, rb_node);
        fprintf(fp, "%s\n", pos->sym.name);
    }

    return ret;
}

size_t dso__fprintf(struct dso *dso, enum map_type type, FILE *fp)
{
    struct rb_node *nd;
    size_t ret = fprintf(fp, "dso: %s (", dso->short_name);

    if (dso->short_name != dso->long_name)
        ret += fprintf(fp, "%s, ", dso->long_name);
    ret += fprintf(fp, "%s, %sloaded, ", map_type__name[type],
               dso->loaded ? "" : "NOT ");
    ret += dso__fprintf_buildid(dso, fp);
    ret += fprintf(fp, ")\n");
    for (nd = rb_first(&dso->symbols[type]); nd; nd = rb_next(nd)) {
        struct symbol *pos = rb_entry(nd, struct symbol, rb_node);
        ret += symbol__fprintf(pos, fp);
    }

    return ret;
}

int kallsyms__parse(const char *filename, void *arg,
            int (*process_symbol)(void *arg, const char *name,
                      char type, u64 start))
{
    char *line = NULL;
    size_t n;
    int err = -1;
    FILE *file = fopen(filename, "r");

    if (file == NULL)
        goto out_failure;

    err = 0;

    while (!feof(file)) {
        u64 start;
        int line_len, len;
        char symbol_type;
        char *symbol_name;

        line_len = getline(&line, &n, file);
        if (line_len < 0 || !line)
            break;

        line[--line_len] = '\0'; /* \n */

        len = hex2u64(line, &start);

        len++;
        if (len + 2 >= line_len)
            continue;

        symbol_type = line[len];
        len += 2;
        symbol_name = line + len;
        len = line_len - len;

        if (len >= KSYM_NAME_LEN) {
            err = -1;
            break;
        }

        err = process_symbol(arg, symbol_name,
                     symbol_type, start);
        if (err)
            break;
    }

    free(line);
    fclose(file);
    return err;

out_failure:
    return -1;
}

struct process_kallsyms_args {
    struct map *map;
    struct dso *dso;
};

static u8 kallsyms2elf_type(char type)
{
    if (type == 'W')
        return STB_WEAK;

    return isupper(type) ? STB_GLOBAL : STB_LOCAL;
}

static int map__process_kallsym_symbol(void *arg, const char *name,
                       char type, u64 start)
{
    struct symbol *sym;
    struct process_kallsyms_args *a = arg;
    struct rb_root *root = &a->dso->symbols[a->map->type];

    if (!symbol_type__is_a(type, a->map->type))
        return 0;

    /*
     * module symbols are not sorted so we add all
     * symbols, setting length to 0, and rely on
     * symbols__fixup_end() to fix it up.
     */
    sym = symbol__new(start, 0, kallsyms2elf_type(type), name);
    if (sym == NULL)
        return -ENOMEM;
    /*
     * We will pass the symbols to the filter later, in
     * map__split_kallsyms, when we have split the maps per module
     */
    symbols__insert(root, sym);

    return 0;
}

/*
 * Loads the function entries in /proc/kallsyms into kernel_map->dso,
 * so that we can in the next step set the symbol ->end address and then
 * call kernel_maps__split_kallsyms.
 */
static int dso__load_all_kallsyms(struct dso *dso, const char *filename,
                  struct map *map)
{
    struct process_kallsyms_args args = { .map = map, .dso = dso, };
    return kallsyms__parse(filename, &args, map__process_kallsym_symbol);
}

/*
 * Split the symbols into maps, making sure there are no overlaps, i.e. the
 * kernel range is broken in several maps, named [kernel].N, as we don't have
 * the original ELF section names vmlinux have.
 */
static int dso__split_kallsyms(struct dso *dso, struct map *map,
                   symbol_filter_t filter)
{
    struct map_groups *kmaps = map__kmap(map)->kmaps;
    struct machine *machine = kmaps->machine;
    struct map *curr_map = map;
    struct symbol *pos;
    int count = 0, moved = 0;   
    struct rb_root *root = &dso->symbols[map->type];
    struct rb_node *next = rb_first(root);
    int kernel_range = 0;

    while (next) {
        char *module;

        pos = rb_entry(next, struct symbol, rb_node);
        next = rb_next(&pos->rb_node);

        module = strchr(pos->name, '\t');
        if (module) {
            if (!symbol_conf.use_modules)
                goto discard_symbol;

            *module++ = '\0';

            if (strcmp(curr_map->dso->short_name, module)) {
                if (curr_map != map &&
                    dso->kernel == DSO_TYPE_GUEST_KERNEL &&
                    machine__is_default_guest(machine)) {
                    /*
                     * We assume all symbols of a module are
                     * continuous in * kallsyms, so curr_map
                     * points to a module and all its
                     * symbols are in its kmap. Mark it as
                     * loaded.
                     */
                    dso__set_loaded(curr_map->dso,
                            curr_map->type);
                }

                curr_map = map_groups__find_by_name(kmaps,
                            map->type, module);
                if (curr_map == NULL) {
                    pr_debug("%s/proc/{kallsyms,modules} "
                             "inconsistency while looking "
                         "for \"%s\" module!\n",
                         machine->root_dir, module);
                    curr_map = map;
                    goto discard_symbol;
                }

                if (curr_map->dso->loaded &&
                    !machine__is_default_guest(machine))
                    goto discard_symbol;
            }
            /*
             * So that we look just like we get from .ko files,
             * i.e. not prelinked, relative to map->start.
             */
            pos->start = curr_map->map_ip(curr_map, pos->start);
            pos->end   = curr_map->map_ip(curr_map, pos->end);
        } else if (curr_map != map) {
            char dso_name[PATH_MAX];
            struct dso *ndso;

            if (count == 0) {
                curr_map = map;
                goto filter_symbol;
            }

            if (dso->kernel == DSO_TYPE_GUEST_KERNEL)
                snprintf(dso_name, sizeof(dso_name),
                    "[guest.kernel].%d",
                    kernel_range++);
            else
                snprintf(dso_name, sizeof(dso_name),
                    "[kernel].%d",
                    kernel_range++);

            ndso = dso__new(dso_name);
            if (ndso == NULL)
                return -1;

            ndso->kernel = dso->kernel;

            curr_map = map__new2(pos->start, ndso, map->type);
            if (curr_map == NULL) {
                dso__delete(ndso);
                return -1;
            }

            curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
            map_groups__insert(kmaps, curr_map);
            ++kernel_range;
        }
filter_symbol:
        if (filter && filter(curr_map, pos)) {
discard_symbol:     rb_erase(&pos->rb_node, root);
            symbol__delete(pos);
        } else {
            if (curr_map != map) {
                rb_erase(&pos->rb_node, root);
                symbols__insert(&curr_map->dso->symbols[curr_map->type], pos);
                ++moved;
            } else
                ++count;
        }
    }

    if (curr_map != map &&
        dso->kernel == DSO_TYPE_GUEST_KERNEL &&
        machine__is_default_guest(kmaps->machine)) {
        dso__set_loaded(curr_map->dso, curr_map->type);
    }

    return count + moved;
}

static bool symbol__restricted_filename(const char *filename,
                    const char *restricted_filename)
{
    bool restricted = false;

    if (symbol_conf.kptr_restrict) {
        char *r = realpath(filename, NULL);

        if (r != NULL) {
            restricted = strcmp(r, restricted_filename) == 0;
            free(r);
            return restricted;
        }
    }

    return restricted;
}

int dso__load_kallsyms(struct dso *dso, const char *filename,
               struct map *map, symbol_filter_t filter)
{
    if (symbol__restricted_filename(filename, "/proc/kallsyms"))
        return -1;

    if (dso__load_all_kallsyms(dso, filename, map) < 0)
        return -1;

    symbols__fixup_duplicate(&dso->symbols[map->type]);
    symbols__fixup_end(&dso->symbols[map->type]);

    if (dso->kernel == DSO_TYPE_GUEST_KERNEL)
        dso->symtab_type = DSO_BINARY_TYPE__GUEST_KALLSYMS;
    else
        dso->symtab_type = DSO_BINARY_TYPE__KALLSYMS;

    return dso__split_kallsyms(dso, map, filter);
}

static int dso__load_perf_map(struct dso *dso, struct map *map,
                  symbol_filter_t filter)
{
    char *line = NULL;
    size_t n;
    FILE *file;
    int nr_syms = 0;

    file = fopen(dso->long_name, "r");
    if (file == NULL)
        goto out_failure;

    while (!feof(file)) {
        u64 start, size;
        struct symbol *sym;
        int line_len, len;

        line_len = getline(&line, &n, file);
        if (line_len < 0)
            break;

        if (!line)
            goto out_failure;

        line[--line_len] = '\0'; /* \n */

        len = hex2u64(line, &start);

        len++;
        if (len + 2 >= line_len)
            continue;

        len += hex2u64(line + len, &size);

        len++;
        if (len + 2 >= line_len)
            continue;

        sym = symbol__new(start, size, STB_GLOBAL, line + len);

        if (sym == NULL)
            goto out_delete_line;

        if (filter && filter(map, sym))
            symbol__delete(sym);
        else {
            symbols__insert(&dso->symbols[map->type], sym);
            nr_syms++;
        }
    }

    free(line);
    fclose(file);

    return nr_syms;

out_delete_line:
    free(line);
out_failure:
    return -1;
}

bool dso__build_id_equal(const struct dso *dso, u8 *build_id)
{
    return memcmp(dso->build_id, build_id, sizeof(dso->build_id)) == 0;
}

bool __dsos__read_build_ids(struct list_head *head, bool with_hits)
{
    bool have_build_id = false;
    struct dso *pos;

    list_for_each_entry(pos, head, node) {
        if (with_hits && !pos->hit)
            continue;
        if (pos->has_build_id) {
            have_build_id = true;
            continue;
        }
        if (filename__read_build_id(pos->long_name, pos->build_id,
                        sizeof(pos->build_id)) > 0) {
            have_build_id     = true;
            pos->has_build_id = true;
        }
    }

    return have_build_id;
}

char dso__symtab_origin(const struct dso *dso)
{
    static const char origin[] = {
        [DSO_BINARY_TYPE__KALLSYMS]     = 'k',
        [DSO_BINARY_TYPE__VMLINUX]      = 'v',
        [DSO_BINARY_TYPE__JAVA_JIT]     = 'j',
        [DSO_BINARY_TYPE__DEBUGLINK]        = 'l',
        [DSO_BINARY_TYPE__BUILD_ID_CACHE]   = 'B',
        [DSO_BINARY_TYPE__FEDORA_DEBUGINFO] = 'f',
        [DSO_BINARY_TYPE__UBUNTU_DEBUGINFO] = 'u',
        [DSO_BINARY_TYPE__BUILDID_DEBUGINFO]    = 'b',
        [DSO_BINARY_TYPE__SYSTEM_PATH_DSO]  = 'd',
        [DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE]  = 'K',
        [DSO_BINARY_TYPE__GUEST_KALLSYMS]   = 'g',
        [DSO_BINARY_TYPE__GUEST_KMODULE]    = 'G',
        [DSO_BINARY_TYPE__GUEST_VMLINUX]    = 'V',
    };

    if (dso == NULL || dso->symtab_type == DSO_BINARY_TYPE__NOT_FOUND)
        return '!';
    return origin[dso->symtab_type];
}

int dso__binary_type_file(struct dso *dso, enum dso_binary_type type,
              char *root_dir, char *file, size_t size)
{
    char build_id_hex[BUILD_ID_SIZE * 2 + 1];
    int ret = 0;

    switch (type) {
    case DSO_BINARY_TYPE__DEBUGLINK: {
        char *debuglink;

        strncpy(file, dso->long_name, size);
        debuglink = file + dso->long_name_len;
        while (debuglink != file && *debuglink != '/')
            debuglink--;
        if (*debuglink == '/')
            debuglink++;
        filename__read_debuglink(dso->long_name, debuglink,
                     size - (debuglink - file));
        }
        break;
    case DSO_BINARY_TYPE__BUILD_ID_CACHE:
        /* skip the locally configured cache if a symfs is given */
        if (symbol_conf.symfs[0] ||
            (dso__build_id_filename(dso, file, size) == NULL))
            ret = -1;
        break;

    case DSO_BINARY_TYPE__FEDORA_DEBUGINFO:
        snprintf(file, size, "%s/usr/lib/debug%s.debug",
             symbol_conf.symfs, dso->long_name);
        break;

    case DSO_BINARY_TYPE__UBUNTU_DEBUGINFO:
        snprintf(file, size, "%s/usr/lib/debug%s",
             symbol_conf.symfs, dso->long_name);
        break;

    case DSO_BINARY_TYPE__BUILDID_DEBUGINFO:
        if (!dso->has_build_id) {
            ret = -1;
            break;
        }

        build_id__sprintf(dso->build_id,
                  sizeof(dso->build_id),
                  build_id_hex);
        snprintf(file, size,
             "%s/usr/lib/debug/.build-id/%.2s/%s.debug",
             symbol_conf.symfs, build_id_hex, build_id_hex + 2);
        break;

    case DSO_BINARY_TYPE__SYSTEM_PATH_DSO:
        snprintf(file, size, "%s%s",
             symbol_conf.symfs, dso->long_name);
        break;

    case DSO_BINARY_TYPE__GUEST_KMODULE:
        snprintf(file, size, "%s%s%s", symbol_conf.symfs,
             root_dir, dso->long_name);
        break;

    case DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE:
        snprintf(file, size, "%s%s", symbol_conf.symfs,
             dso->long_name);
        break;

    default:
    case DSO_BINARY_TYPE__KALLSYMS:
    case DSO_BINARY_TYPE__VMLINUX:
    case DSO_BINARY_TYPE__GUEST_KALLSYMS:
    case DSO_BINARY_TYPE__GUEST_VMLINUX:
    case DSO_BINARY_TYPE__JAVA_JIT:
    case DSO_BINARY_TYPE__NOT_FOUND:
        ret = -1;
        break;
    }

    return ret;
}

int dso__load(struct dso *dso, struct map *map, symbol_filter_t filter)
{
    char *name;
    int ret = -1;
    u_int i;
    struct machine *machine;
    char *root_dir = (char *) "";
    int ss_pos = 0;
    struct symsrc ss_[2];
    struct symsrc *syms_ss = NULL, *runtime_ss = NULL;

    dso__set_loaded(dso, map->type);

    if (dso->kernel == DSO_TYPE_KERNEL)
        return dso__load_kernel_sym(dso, map, filter);
    else if (dso->kernel == DSO_TYPE_GUEST_KERNEL)
        return dso__load_guest_kernel_sym(dso, map, filter);

    if (map->groups && map->groups->machine)
        machine = map->groups->machine;
    else
        machine = NULL;

    name = malloc(PATH_MAX);
    if (!name)
        return -1;

    dso->adjust_symbols = 0;

    if (strncmp(dso->name, "/tmp/perf-", 10) == 0) {
        struct stat st;

        if (lstat(dso->name, &st) < 0)
            return -1;

        if (st.st_uid && (st.st_uid != geteuid())) {
            pr_warning("File %s not owned by current user or root, "
                "ignoring it.\n", dso->name);
            return -1;
        }

        ret = dso__load_perf_map(dso, map, filter);
        dso->symtab_type = ret > 0 ? DSO_BINARY_TYPE__JAVA_JIT :
                         DSO_BINARY_TYPE__NOT_FOUND;
        return ret;
    }

    if (machine)
        root_dir = machine->root_dir;

    /* Iterate over candidate debug images.
     * Keep track of "interesting" ones (those which have a symtab, dynsym,
     * and/or opd section) for processing.
     */
    for (i = 0; i < DSO_BINARY_TYPE__SYMTAB_CNT; i++) {
        struct symsrc *ss = &ss_[ss_pos];
        bool next_slot = false;

        enum dso_binary_type symtab_type = binary_type_symtab[i];

        if (dso__binary_type_file(dso, symtab_type,
                      root_dir, name, PATH_MAX))
            continue;

        /* Name is now the name of the next image to try */
        if (symsrc__init(ss, dso, name, symtab_type) < 0)
            continue;

        if (!syms_ss && symsrc__has_symtab(ss)) {
            syms_ss = ss;
            next_slot = true;
        }

        if (!runtime_ss && symsrc__possibly_runtime(ss)) {
            runtime_ss = ss;
            next_slot = true;
        }

        if (next_slot) {
            ss_pos++;

            if (syms_ss && runtime_ss)
                break;
        }

    }

    if (!runtime_ss && !syms_ss)
        goto out_free;

    if (runtime_ss && !syms_ss) {
        syms_ss = runtime_ss;
    }

    /* We'll have to hope for the best */
    if (!runtime_ss && syms_ss)
        runtime_ss = syms_ss;

    if (syms_ss)
        ret = dso__load_sym(dso, map, syms_ss, runtime_ss, filter, 0);
    else
        ret = -1;

    if (ret > 0) {
        int nr_plt;

        nr_plt = dso__synthesize_plt_symbols(dso, runtime_ss, map, filter);
        if (nr_plt > 0)
            ret += nr_plt;
    }

    for (; ss_pos > 0; ss_pos--)
        symsrc__destroy(&ss_[ss_pos - 1]);
out_free:
    free(name);
    if (ret < 0 && strstr(dso->name, " (deleted)") != NULL)
        return 0;
    return ret;
}

struct map *map_groups__find_by_name(struct map_groups *mg,
                     enum map_type type, const char *name)
{
    struct rb_node *nd;

    for (nd = rb_first(&mg->maps[type]); nd; nd = rb_next(nd)) {
        struct map *map = rb_entry(nd, struct map, rb_node);

        if (map->dso && strcmp(map->dso->short_name, name) == 0)
            return map;
    }

    return NULL;
}

static int dso__kernel_module_get_build_id(struct dso *dso,
                       const char *root_dir)
{
    char filename[PATH_MAX];
    /*
     * kernel module short names are of the form "[module]" and
     * we need just "module" here.
     */
    const char *name = dso->short_name + 1;

    snprintf(filename, sizeof(filename),
         "%s/sys/module/%.*s/notes/.note.gnu.build-id",
         root_dir, (int)strlen(name) - 1, name);

    if (sysfs__read_build_id(filename, dso->build_id,
                 sizeof(dso->build_id)) == 0)
        dso->has_build_id = true;

    return 0;
}

static int map_groups__set_modules_path_dir(struct map_groups *mg,
                const char *dir_name)
{
    struct dirent *dent;
    DIR *dir = opendir(dir_name);
    int ret = 0;

    if (!dir) {
        pr_debug("%s: cannot open %s dir\n", __func__, dir_name);
        return -1;
    }

    while ((dent = readdir(dir)) != NULL) {
        char path[PATH_MAX];
        struct stat st;

        /*sshfs might return bad dent->d_type, so we have to stat*/
        snprintf(path, sizeof(path), "%s/%s", dir_name, dent->d_name);
        if (stat(path, &st))
            continue;

        if (S_ISDIR(st.st_mode)) {
            if (!strcmp(dent->d_name, ".") ||
                !strcmp(dent->d_name, ".."))
                continue;

            ret = map_groups__set_modules_path_dir(mg, path);
            if (ret < 0)
                goto out;
        } else {
            char *dot = strrchr(dent->d_name, '.'),
                 dso_name[PATH_MAX];
            struct map *map;
            char *long_name;

            if (dot == NULL || strcmp(dot, ".ko"))
                continue;
            snprintf(dso_name, sizeof(dso_name), "[%.*s]",
                 (int)(dot - dent->d_name), dent->d_name);

            strxfrchar(dso_name, '-', '_');
            map = map_groups__find_by_name(mg, MAP__FUNCTION,
                               dso_name);
            if (map == NULL)
                continue;

            long_name = strdup(path);
            if (long_name == NULL) {
                ret = -1;
                goto out;
            }
            dso__set_long_name(map->dso, long_name);
            map->dso->lname_alloc = 1;
            dso__kernel_module_get_build_id(map->dso, "");
        }
    }

out:
    closedir(dir);
    return ret;
}

static char *get_kernel_version(const char *root_dir)
{
    char version[PATH_MAX];
    FILE *file;
    char *name, *tmp;
    const char *prefix = "Linux version ";

    sprintf(version, "%s/proc/version", root_dir);
    file = fopen(version, "r");
    if (!file)
        return NULL;

    version[0] = '\0';
    tmp = fgets(version, sizeof(version), file);
    fclose(file);

    name = strstr(version, prefix);
    if (!name)
        return NULL;
    name += strlen(prefix);
    tmp = strchr(name, ' ');
    if (tmp)
        *tmp = '\0';

    return strdup(name);
}

static int machine__set_modules_path(struct machine *machine)
{
    char *version;
    char modules_path[PATH_MAX];

    version = get_kernel_version(machine->root_dir);
    if (!version)
        return -1;

    snprintf(modules_path, sizeof(modules_path), "%s/lib/modules/%s/kernel",
         machine->root_dir, version);
    free(version);

    return map_groups__set_modules_path_dir(&machine->kmaps, modules_path);
}

struct map *machine__new_module(struct machine *machine, u64 start,
                const char *filename)
{
    struct map *map;
    struct dso *dso = __dsos__findnew(&machine->kernel_dsos, filename);

    if (dso == NULL)
        return NULL;

    map = map__new2(start, dso, MAP__FUNCTION);
    if (map == NULL)
        return NULL;

    if (machine__is_host(machine))
        dso->symtab_type = DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE;
    else
        dso->symtab_type = DSO_BINARY_TYPE__GUEST_KMODULE;
    map_groups__insert(&machine->kmaps, map);
    return map;
}

static int machine__create_modules(struct machine *machine)
{
    char *line = NULL;
    size_t n;
    FILE *file;
    struct map *map;
    const char *modules;
    char path[PATH_MAX];

    if (machine__is_default_guest(machine))
        modules = symbol_conf.default_guest_modules;
    else {
        sprintf(path, "%s/proc/modules", machine->root_dir);
        modules = path;
    }

    if (symbol__restricted_filename(path, "/proc/modules"))
        return -1;

    file = fopen(modules, "r");
    if (file == NULL)
        return -1;

    while (!feof(file)) {
        char name[PATH_MAX];
        u64 start;
        char *sep;
        int line_len;

        line_len = getline(&line, &n, file);
        if (line_len < 0)
            break;

        if (!line)
            goto out_failure;

        line[--line_len] = '\0'; /* \n */

        sep = strrchr(line, 'x');
        if (sep == NULL)
            continue;

        hex2u64(sep + 1, &start);

        sep = strchr(line, ' ');
        if (sep == NULL)
            continue;

        *sep = '\0';

        snprintf(name, sizeof(name), "[%s]", line);
        map = machine__new_module(machine, start, name);
        if (map == NULL)
            goto out_delete_line;
        dso__kernel_module_get_build_id(map->dso, machine->root_dir);
    }

    free(line);
    fclose(file);

    return machine__set_modules_path(machine);

out_delete_line:
    free(line);
out_failure:
    return -1;
}

int dso__load_vmlinux(struct dso *dso, struct map *map,
              const char *vmlinux, symbol_filter_t filter)
{
    int err = -1;
    struct symsrc ss;
    char symfs_vmlinux[PATH_MAX];
    enum dso_binary_type symtab_type;

    snprintf(symfs_vmlinux, sizeof(symfs_vmlinux), "%s%s",
         symbol_conf.symfs, vmlinux);

    if (dso->kernel == DSO_TYPE_GUEST_KERNEL)
        symtab_type = DSO_BINARY_TYPE__GUEST_VMLINUX;
    else
        symtab_type = DSO_BINARY_TYPE__VMLINUX;

    if (symsrc__init(&ss, dso, symfs_vmlinux, symtab_type))
        return -1;

    err = dso__load_sym(dso, map, &ss, &ss, filter, 0);
    symsrc__destroy(&ss);

    if (err > 0) {
        dso__set_long_name(dso, (char *)vmlinux);
        dso__set_loaded(dso, map->type);
        pr_debug("Using %s for symbols\n", symfs_vmlinux);
    }

    return err;
}

int dso__load_vmlinux_path(struct dso *dso, struct map *map,
               symbol_filter_t filter)
{
    int i, err = 0;
    char *filename;

    pr_debug("Looking at the vmlinux_path (%d entries long)\n",
         vmlinux_path__nr_entries + 1);

    filename = dso__build_id_filename(dso, NULL, 0);
    if (filename != NULL) {
        err = dso__load_vmlinux(dso, map, filename, filter);
        if (err > 0)
            goto out;
        free(filename);
    }

    for (i = 0; i < vmlinux_path__nr_entries; ++i) {
        err = dso__load_vmlinux(dso, map, vmlinux_path[i], filter);
        if (err > 0) {
            dso__set_long_name(dso, strdup(vmlinux_path[i]));
            break;
        }
    }
out:
    return err;
}

static int dso__load_kernel_sym(struct dso *dso, struct map *map,
                symbol_filter_t filter)
{
    int err;
    const char *kallsyms_filename = NULL;
    char *kallsyms_allocated_filename = NULL;
    /*
     * Step 1: if the user specified a kallsyms or vmlinux filename, use
     * it and only it, reporting errors to the user if it cannot be used.
     *
     * For instance, try to analyse an ARM perf.data file _without_ a
     * build-id, or if the user specifies the wrong path to the right
     * vmlinux file, obviously we can't fallback to another vmlinux (a
     * x86_86 one, on the machine where analysis is being performed, say),
     * or worse, /proc/kallsyms.
     *
     * If the specified file _has_ a build-id and there is a build-id
     * section in the perf.data file, we will still do the expected
     * validation in dso__load_vmlinux and will bail out if they don't
     * match.
     */
    if (symbol_conf.kallsyms_name != NULL) {
        kallsyms_filename = symbol_conf.kallsyms_name;
        goto do_kallsyms;
    }

    if (symbol_conf.vmlinux_name != NULL) {
        err = dso__load_vmlinux(dso, map,
                    symbol_conf.vmlinux_name, filter);
        if (err > 0) {
            dso__set_long_name(dso,
                       strdup(symbol_conf.vmlinux_name));
            goto out_fixup;
        }
        return err;
    }

    if (vmlinux_path != NULL) {
        err = dso__load_vmlinux_path(dso, map, filter);
        if (err > 0)
            goto out_fixup;
    }

    /* do not try local files if a symfs was given */
    if (symbol_conf.symfs[0] != 0)
        return -1;

    /*
     * Say the kernel DSO was created when processing the build-id header table,
     * we have a build-id, so check if it is the same as the running kernel,
     * using it if it is.
     */
    if (dso->has_build_id) {
        u8 kallsyms_build_id[BUILD_ID_SIZE];
        char sbuild_id[BUILD_ID_SIZE * 2 + 1];

        if (sysfs__read_build_id("/sys/kernel/notes", kallsyms_build_id,
                     sizeof(kallsyms_build_id)) == 0) {
            if (dso__build_id_equal(dso, kallsyms_build_id)) {
                kallsyms_filename = "/proc/kallsyms";
                goto do_kallsyms;
            }
        }
        /*
         * Now look if we have it on the build-id cache in
         * $HOME/.debug/[kernel.kallsyms].
         */
        build_id__sprintf(dso->build_id, sizeof(dso->build_id),
                  sbuild_id);

        if (asprintf(&kallsyms_allocated_filename,
                 "%s/.debug/[kernel.kallsyms]/%s",
                 getenv("HOME"), sbuild_id) == -1) {
            pr_err("Not enough memory for kallsyms file lookup\n");
            return -1;
        }

        kallsyms_filename = kallsyms_allocated_filename;

        if (access(kallsyms_filename, F_OK)) {
            pr_err("No kallsyms or vmlinux with build-id %s "
                   "was found\n", sbuild_id);
            free(kallsyms_allocated_filename);
            return -1;
        }
    } else {
        /*
         * Last resort, if we don't have a build-id and couldn't find
         * any vmlinux file, try the running kernel kallsyms table.
         */
        kallsyms_filename = "/proc/kallsyms";
    }

do_kallsyms:
    err = dso__load_kallsyms(dso, kallsyms_filename, map, filter);
    if (err > 0)
        pr_debug("Using %s for symbols\n", kallsyms_filename);
    free(kallsyms_allocated_filename);

    if (err > 0) {
        dso__set_long_name(dso, strdup("[kernel.kallsyms]"));
out_fixup:
        map__fixup_start(map);
        map__fixup_end(map);
    }

    return err;
}

static int dso__load_guest_kernel_sym(struct dso *dso, struct map *map,
                      symbol_filter_t filter)
{
    int err;
    const char *kallsyms_filename = NULL;
    struct machine *machine;
    char path[PATH_MAX];

    if (!map->groups) {
        pr_debug("Guest kernel map hasn't the point to groups\n");
        return -1;
    }
    machine = map->groups->machine;

    if (machine__is_default_guest(machine)) {
        /*
         * if the user specified a vmlinux filename, use it and only
         * it, reporting errors to the user if it cannot be used.
         * Or use file guest_kallsyms inputted by user on commandline
         */
        if (symbol_conf.default_guest_vmlinux_name != NULL) {
            err = dso__load_vmlinux(dso, map,
                symbol_conf.default_guest_vmlinux_name, filter);
            goto out_try_fixup;
        }

        kallsyms_filename = symbol_conf.default_guest_kallsyms;
        if (!kallsyms_filename)
            return -1;
    } else {
        sprintf(path, "%s/proc/kallsyms", machine->root_dir);
        kallsyms_filename = path;
    }

    err = dso__load_kallsyms(dso, kallsyms_filename, map, filter);
    if (err > 0)
        pr_debug("Using %s for symbols\n", kallsyms_filename);

out_try_fixup:
    if (err > 0) {
        if (kallsyms_filename != NULL) {
            machine__mmap_name(machine, path, sizeof(path));
            dso__set_long_name(dso, strdup(path));
        }
        map__fixup_start(map);
        map__fixup_end(map);
    }

    return err;
}

void dsos__add(struct list_head *head, struct dso *dso)
{
    list_add_tail(&dso->node, head);
}

struct dso *dsos__find(struct list_head *head, const char *name)
{
    struct dso *pos;

    list_for_each_entry(pos, head, node)
        if (strcmp(pos->long_name, name) == 0)
            return pos;
    return NULL;
}

struct dso *__dsos__findnew(struct list_head *head, const char *name)
{
    struct dso *dso = dsos__find(head, name);

    if (!dso) {
        dso = dso__new(name);
        if (dso != NULL) {
            dsos__add(head, dso);
            dso__set_basename(dso);
        }
    }

    return dso;
}

size_t __dsos__fprintf(struct list_head *head, FILE *fp)
{
    struct dso *pos;
    size_t ret = 0;

    list_for_each_entry(pos, head, node) {
        int i;
        for (i = 0; i < MAP__NR_TYPES; ++i)
            ret += dso__fprintf(pos, i, fp);
    }

    return ret;
}

size_t machines__fprintf_dsos(struct rb_root *machines, FILE *fp)
{
    struct rb_node *nd;
    size_t ret = 0;

    for (nd = rb_first(machines); nd; nd = rb_next(nd)) {
        struct machine *pos = rb_entry(nd, struct machine, rb_node);
        ret += __dsos__fprintf(&pos->kernel_dsos, fp);
        ret += __dsos__fprintf(&pos->user_dsos, fp);
    }

    return ret;
}

static size_t __dsos__fprintf_buildid(struct list_head *head, FILE *fp,
                      bool with_hits)
{
    struct dso *pos;
    size_t ret = 0;

    list_for_each_entry(pos, head, node) {
        if (with_hits && !pos->hit)
            continue;
        ret += dso__fprintf_buildid(pos, fp);
        ret += fprintf(fp, " %s\n", pos->long_name);
    }
    return ret;
}

size_t machine__fprintf_dsos_buildid(struct machine *machine, FILE *fp,
                     bool with_hits)
{
    return __dsos__fprintf_buildid(&machine->kernel_dsos, fp, with_hits) +
           __dsos__fprintf_buildid(&machine->user_dsos, fp, with_hits);
}

size_t machines__fprintf_dsos_buildid(struct rb_root *machines,
                      FILE *fp, bool with_hits)
{
    struct rb_node *nd;
    size_t ret = 0;

    for (nd = rb_first(machines); nd; nd = rb_next(nd)) {
        struct machine *pos = rb_entry(nd, struct machine, rb_node);
        ret += machine__fprintf_dsos_buildid(pos, fp, with_hits);
    }
    return ret;
}

static struct dso*
dso__kernel_findnew(struct machine *machine, const char *name,
            const char *short_name, int dso_type)
{
    /*
     * The kernel dso could be created by build_id processing.
     */
    struct dso *dso = __dsos__findnew(&machine->kernel_dsos, name);

    /*
     * We need to run this in all cases, since during the build_id
     * processing we had no idea this was the kernel dso.
     */
    if (dso != NULL) {
        dso__set_short_name(dso, short_name);
        dso->kernel = dso_type;
    }

    return dso;
}

void dso__read_running_kernel_build_id(struct dso *dso, struct machine *machine)
{
    char path[PATH_MAX];

    if (machine__is_default_guest(machine))
        return;
    sprintf(path, "%s/sys/kernel/notes", machine->root_dir);
    if (sysfs__read_build_id(path, dso->build_id,
                 sizeof(dso->build_id)) == 0)
        dso->has_build_id = true;
}

static struct dso *machine__get_kernel(struct machine *machine)
{
    const char *vmlinux_name = NULL;
    struct dso *kernel;

    if (machine__is_host(machine)) {
        vmlinux_name = symbol_conf.vmlinux_name;
        if (!vmlinux_name)
            vmlinux_name = "[kernel.kallsyms]";

        kernel = dso__kernel_findnew(machine, vmlinux_name,
                         "[kernel]",
                         DSO_TYPE_KERNEL);
    } else {
        char bf[PATH_MAX];

        if (machine__is_default_guest(machine))
            vmlinux_name = symbol_conf.default_guest_vmlinux_name;
        if (!vmlinux_name)
            vmlinux_name = machine__mmap_name(machine, bf,
                              sizeof(bf));

        kernel = dso__kernel_findnew(machine, vmlinux_name,
                         "[guest.kernel]",
                         DSO_TYPE_GUEST_KERNEL);
    }

    if (kernel != NULL && (!kernel->has_build_id))
        dso__read_running_kernel_build_id(kernel, machine);

    return kernel;
}

struct process_args {
    u64 start;
};

static int symbol__in_kernel(void *arg, const char *name,
                 char type __maybe_unused, u64 start)
{
    struct process_args *args = arg;

    if (strchr(name, '['))
        return 0;

    args->start = start;
    return 1;
}

/* Figure out the start address of kernel map from /proc/kallsyms */
static u64 machine__get_kernel_start_addr(struct machine *machine)
{
    const char *filename;
    char path[PATH_MAX];
    struct process_args args;

    if (machine__is_host(machine)) {
        filename = "/proc/kallsyms";
    } else {
        if (machine__is_default_guest(machine))
            filename = (char *)symbol_conf.default_guest_kallsyms;
        else {
            sprintf(path, "%s/proc/kallsyms", machine->root_dir);
            filename = path;
        }
    }

    if (symbol__restricted_filename(filename, "/proc/kallsyms"))
        return 0;

    if (kallsyms__parse(filename, &args, symbol__in_kernel) <= 0)
        return 0;

    return args.start;
}

int __machine__create_kernel_maps(struct machine *machine, struct dso *kernel)
{
    enum map_type type;
    u64 start = machine__get_kernel_start_addr(machine);

    for (type = 0; type < MAP__NR_TYPES; ++type) {
        struct kmap *kmap;

        machine->vmlinux_maps[type] = map__new2(start, kernel, type);
        if (machine->vmlinux_maps[type] == NULL)
            return -1;

        machine->vmlinux_maps[type]->map_ip =
            machine->vmlinux_maps[type]->unmap_ip =
                identity__map_ip;
        kmap = map__kmap(machine->vmlinux_maps[type]);
        kmap->kmaps = &machine->kmaps;
        map_groups__insert(&machine->kmaps,
                   machine->vmlinux_maps[type]);
    }

    return 0;
}

void machine__destroy_kernel_maps(struct machine *machine)
{
    enum map_type type;

    for (type = 0; type < MAP__NR_TYPES; ++type) {
        struct kmap *kmap;

        if (machine->vmlinux_maps[type] == NULL)
            continue;

        kmap = map__kmap(machine->vmlinux_maps[type]);
        map_groups__remove(&machine->kmaps,
                   machine->vmlinux_maps[type]);
        if (kmap->ref_reloc_sym) {
            /*
             * ref_reloc_sym is shared among all maps, so free just
             * on one of them.
             */
            if (type == MAP__FUNCTION) {
                free((char *)kmap->ref_reloc_sym->name);
                kmap->ref_reloc_sym->name = NULL;
                free(kmap->ref_reloc_sym);
            }
            kmap->ref_reloc_sym = NULL;
        }

        map__delete(machine->vmlinux_maps[type]);
        machine->vmlinux_maps[type] = NULL;
    }
}

int machine__create_kernel_maps(struct machine *machine)
{
    struct dso *kernel = machine__get_kernel(machine);

    if (kernel == NULL ||
        __machine__create_kernel_maps(machine, kernel) < 0)
        return -1;

    if (symbol_conf.use_modules && machine__create_modules(machine) < 0) {
        if (machine__is_host(machine))
            pr_debug("Problems creating module maps, "
                 "continuing anyway...\n");
        else
            pr_debug("Problems creating module maps for guest %d, "
                 "continuing anyway...\n", machine->pid);
    }

    /*
     * Now that we have all the maps created, just set the ->end of them:
     */
    map_groups__fixup_end(&machine->kmaps);
    return 0;
}

static void vmlinux_path__exit(void)
{
    while (--vmlinux_path__nr_entries >= 0) {
        free(vmlinux_path[vmlinux_path__nr_entries]);
        vmlinux_path[vmlinux_path__nr_entries] = NULL;
    }

    free(vmlinux_path);
    vmlinux_path = NULL;
}

static int vmlinux_path__init(void)
{
    struct utsname uts;
    char bf[PATH_MAX];

    vmlinux_path = malloc(sizeof(char *) * 5);
    if (vmlinux_path == NULL)
        return -1;

    vmlinux_path[vmlinux_path__nr_entries] = strdup("vmlinux");
    if (vmlinux_path[vmlinux_path__nr_entries] == NULL)
        goto out_fail;
    ++vmlinux_path__nr_entries;
    vmlinux_path[vmlinux_path__nr_entries] = strdup("/boot/vmlinux");
    if (vmlinux_path[vmlinux_path__nr_entries] == NULL)
        goto out_fail;
    ++vmlinux_path__nr_entries;

    /* only try running kernel version if no symfs was given */
    if (symbol_conf.symfs[0] != 0)
        return 0;

    if (uname(&uts) < 0)
        return -1;

    snprintf(bf, sizeof(bf), "/boot/vmlinux-%s", uts.release);
    vmlinux_path[vmlinux_path__nr_entries] = strdup(bf);
    if (vmlinux_path[vmlinux_path__nr_entries] == NULL)
        goto out_fail;
    ++vmlinux_path__nr_entries;
    snprintf(bf, sizeof(bf), "/lib/modules/%s/build/vmlinux", uts.release);
    vmlinux_path[vmlinux_path__nr_entries] = strdup(bf);
    if (vmlinux_path[vmlinux_path__nr_entries] == NULL)
        goto out_fail;
    ++vmlinux_path__nr_entries;
    snprintf(bf, sizeof(bf), "/usr/lib/debug/lib/modules/%s/vmlinux",
         uts.release);
    vmlinux_path[vmlinux_path__nr_entries] = strdup(bf);
    if (vmlinux_path[vmlinux_path__nr_entries] == NULL)
        goto out_fail;
    ++vmlinux_path__nr_entries;

    return 0;

out_fail:
    vmlinux_path__exit();
    return -1;
}

size_t machine__fprintf_vmlinux_path(struct machine *machine, FILE *fp)
{
    int i;
    size_t printed = 0;
    struct dso *kdso = machine->vmlinux_maps[MAP__FUNCTION]->dso;

    if (kdso->has_build_id) {
        char filename[PATH_MAX];
        if (dso__build_id_filename(kdso, filename, sizeof(filename)))
            printed += fprintf(fp, "[0] %s\n", filename);
    }

    for (i = 0; i < vmlinux_path__nr_entries; ++i)
        printed += fprintf(fp, "[%d] %s\n",
                   i + kdso->has_build_id, vmlinux_path[i]);

    return printed;
}

static int setup_list(struct strlist **list, const char *list_str,
              const char *list_name)
{
    if (list_str == NULL)
        return 0;

    *list = strlist__new(true, list_str);
    if (!*list) {
        pr_err("problems parsing %s list\n", list_name);
        return -1;
    }
    return 0;
}

static bool symbol__read_kptr_restrict(void)
{
    bool value = false;

    if (geteuid() != 0) {
        FILE *fp = fopen("/proc/sys/kernel/kptr_restrict", "r");
        if (fp != NULL) {
            char line[8];

            if (fgets(line, sizeof(line), fp) != NULL)
                value = atoi(line) != 0;

            fclose(fp);
        }
    }

    return value;
}

int symbol__init(void)
{
    const char *symfs;

    if (symbol_conf.initialized)
        return 0;

    symbol_conf.priv_size = PERF_ALIGN(symbol_conf.priv_size, sizeof(u64));

    symbol__elf_init();

    if (symbol_conf.sort_by_name)
        symbol_conf.priv_size += (sizeof(struct symbol_name_rb_node) -
                      sizeof(struct symbol));

    if (symbol_conf.try_vmlinux_path && vmlinux_path__init() < 0)
        return -1;

    if (symbol_conf.field_sep && *symbol_conf.field_sep == '.') {
        pr_err("'.' is the only non valid --field-separator argument\n");
        return -1;
    }

    if (setup_list(&symbol_conf.dso_list,
               symbol_conf.dso_list_str, "dso") < 0)
        return -1;

    if (setup_list(&symbol_conf.comm_list,
               symbol_conf.comm_list_str, "comm") < 0)
        goto out_free_dso_list;

    if (setup_list(&symbol_conf.sym_list,
               symbol_conf.sym_list_str, "symbol") < 0)
        goto out_free_comm_list;

    /*
     * A path to symbols of "/" is identical to ""
     * reset here for simplicity.
     */
    symfs = realpath(symbol_conf.symfs, NULL);
    if (symfs == NULL)
        symfs = symbol_conf.symfs;
    if (strcmp(symfs, "/") == 0)
        symbol_conf.symfs = "";
    if (symfs != symbol_conf.symfs)
        free((void *)symfs);

    symbol_conf.kptr_restrict = symbol__read_kptr_restrict();

    symbol_conf.initialized = true;
    return 0;

out_free_comm_list:
    strlist__delete(symbol_conf.comm_list);
out_free_dso_list:
    strlist__delete(symbol_conf.dso_list);
    return -1;
}

void symbol__exit(void)
{
    if (!symbol_conf.initialized)
        return;
    strlist__delete(symbol_conf.sym_list);
    strlist__delete(symbol_conf.dso_list);
    strlist__delete(symbol_conf.comm_list);
    vmlinux_path__exit();
    symbol_conf.sym_list = symbol_conf.dso_list = symbol_conf.comm_list = NULL;
    symbol_conf.initialized = false;
}

int machines__create_kernel_maps(struct rb_root *machines, pid_t pid)
{
    struct machine *machine = machines__findnew(machines, pid);

    if (machine == NULL)
        return -1;

    return machine__create_kernel_maps(machine);
}

static int hex(char ch)
{
    if ((ch >= '0') && (ch <= '9'))
        return ch - '0';
    if ((ch >= 'a') && (ch <= 'f'))
        return ch - 'a' + 10;
    if ((ch >= 'A') && (ch <= 'F'))
        return ch - 'A' + 10;
    return -1;
}

/*
 * While we find nice hex chars, build a long_val.
 * Return number of chars processed.
 */
int hex2u64(const char *ptr, u64 *long_val)
{
    const char *p = ptr;
    *long_val = 0;

    while (*p) {
        const int hex_val = hex(*p);

        if (hex_val < 0)
            break;

        *long_val = (*long_val << 4) | hex_val;
        p++;
    }

    return p - ptr;
}

char *strxfrchar(char *s, char from, char to)
{
    char *p = s;

    while ((p = strchr(p, from)) != NULL)
        *p++ = to;

    return s;
}

int machines__create_guest_kernel_maps(struct rb_root *machines)
{
    int ret = 0;
    struct dirent **namelist = NULL;
    int i, items = 0;
    char path[PATH_MAX];
    pid_t pid;
    char *endp;

    if (symbol_conf.default_guest_vmlinux_name ||
        symbol_conf.default_guest_modules ||
        symbol_conf.default_guest_kallsyms) {
        machines__create_kernel_maps(machines, DEFAULT_GUEST_KERNEL_ID);
    }

    if (symbol_conf.guestmount) {
        items = scandir(symbol_conf.guestmount, &namelist, NULL, NULL);
        if (items <= 0)
            return -ENOENT;
        for (i = 0; i < items; i++) {
            if (!isdigit(namelist[i]->d_name[0])) {
                /* Filter out . and .. */
                continue;
            }
            pid = (pid_t)strtol(namelist[i]->d_name, &endp, 10);
            if ((*endp != '\0') ||
                (endp == namelist[i]->d_name) ||
                (errno == ERANGE)) {
                pr_debug("invalid directory (%s). Skipping.\n",
                     namelist[i]->d_name);
                continue;
            }
            sprintf(path, "%s/%s/proc/kallsyms",
                symbol_conf.guestmount,
                namelist[i]->d_name);
            ret = access(path, R_OK);
            if (ret) {
                pr_debug("Can't access file %s\n", path);
                goto failure;
            }
            machines__create_kernel_maps(machines, pid);
        }
failure:
        free(namelist);
    }

    return ret;
}

void machines__destroy_guest_kernel_maps(struct rb_root *machines)
{
    struct rb_node *next = rb_first(machines);

    while (next) {
        struct machine *pos = rb_entry(next, struct machine, rb_node);

        next = rb_next(&pos->rb_node);
        rb_erase(&pos->rb_node, machines);
        machine__delete(pos);
    }
}

int machine__load_kallsyms(struct machine *machine, const char *filename,
               enum map_type type, symbol_filter_t filter)
{
    struct map *map = machine->vmlinux_maps[type];
    int ret = dso__load_kallsyms(map->dso, filename, map, filter);

    if (ret > 0) {
        dso__set_loaded(map->dso, type);
        /*
         * Since /proc/kallsyms will have multiple sessions for the
         * kernel, with modules between them, fixup the end of all
         * sections.
         */
        __map_groups__fixup_end(&machine->kmaps, type);
    }

    return ret;
}

int machine__load_vmlinux_path(struct machine *machine, enum map_type type,
                   symbol_filter_t filter)
{
    struct map *map = machine->vmlinux_maps[type];
    int ret = dso__load_vmlinux_path(map->dso, map, filter);

    if (ret > 0) {
        dso__set_loaded(map->dso, type);
        map__reloc_vmlinux(map);
    }

    return ret;
}

struct map *dso__new_map(const char *name)
{
    struct map *map = NULL;
    struct dso *dso = dso__new(name);

    if (dso)
        map = map__new2(0, dso, MAP__FUNCTION);

    return map;
}

static int open_dso(struct dso *dso, struct machine *machine)
{
    char *root_dir = (char *) "";
    char *name;
    int fd;

    name = malloc(PATH_MAX);
    if (!name)
        return -ENOMEM;

    if (machine)
        root_dir = machine->root_dir;

    if (dso__binary_type_file(dso, dso->data_type,
                  root_dir, name, PATH_MAX)) {
        free(name);
        return -EINVAL;
    }

    fd = open(name, O_RDONLY);
    free(name);
    return fd;
}

int dso__data_fd(struct dso *dso, struct machine *machine)
{
    int i = 0;

    if (dso->data_type != DSO_BINARY_TYPE__NOT_FOUND)
        return open_dso(dso, machine);

    do {
        int fd;

        dso->data_type = binary_type_data[i++];

        fd = open_dso(dso, machine);
        if (fd >= 0)
            return fd;

    } while (dso->data_type != DSO_BINARY_TYPE__NOT_FOUND);

    return -EINVAL;
}

static void
dso_cache__free(struct rb_root *root)
{
    struct rb_node *next = rb_first(root);

    while (next) {
        struct dso_cache *cache;

        cache = rb_entry(next, struct dso_cache, rb_node);
        next = rb_next(&cache->rb_node);
        rb_erase(&cache->rb_node, root);
        free(cache);
    }
}

static struct dso_cache*
dso_cache__find(struct rb_root *root, u64 offset)
{
    struct rb_node **p = &root->rb_node;
    struct rb_node *parent = NULL;
    struct dso_cache *cache;

    while (*p != NULL) {
        u64 end;

        parent = *p;
        cache = rb_entry(parent, struct dso_cache, rb_node);
        end = cache->offset + DSO__DATA_CACHE_SIZE;

        if (offset < cache->offset)
            p = &(*p)->rb_left;
        else if (offset >= end)
            p = &(*p)->rb_right;
        else
            return cache;
    }
    return NULL;
}

static void
dso_cache__insert(struct rb_root *root, struct dso_cache *new)
{
    struct rb_node **p = &root->rb_node;
    struct rb_node *parent = NULL;
    struct dso_cache *cache;
    u64 offset = new->offset;

    while (*p != NULL) {
        u64 end;

        parent = *p;
        cache = rb_entry(parent, struct dso_cache, rb_node);
        end = cache->offset + DSO__DATA_CACHE_SIZE;

        if (offset < cache->offset)
            p = &(*p)->rb_left;
        else if (offset >= end)
            p = &(*p)->rb_right;
    }

    rb_link_node(&new->rb_node, parent, p);
    rb_insert_color(&new->rb_node, root);
}

static ssize_t
dso_cache__memcpy(struct dso_cache *cache, u64 offset,
          u8 *data, u64 size)
{
    u64 cache_offset = offset - cache->offset;
    u64 cache_size   = min(cache->size - cache_offset, size);

    memcpy(data, cache->data + cache_offset, cache_size);
    return cache_size;
}

static ssize_t
dso_cache__read(struct dso *dso, struct machine *machine,
         u64 offset, u8 *data, ssize_t size)
{
    struct dso_cache *cache;
    ssize_t ret;
    int fd;

    fd = dso__data_fd(dso, machine);
    if (fd < 0)
        return -1;

    do {
        u64 cache_offset;

        ret = -ENOMEM;

        cache = zalloc(sizeof(*cache) + DSO__DATA_CACHE_SIZE);
        if (!cache)
            break;

        cache_offset = offset & DSO__DATA_CACHE_MASK;
        ret = -EINVAL;

        if (-1 == lseek(fd, cache_offset, SEEK_SET))
            break;

        ret = read(fd, cache->data, DSO__DATA_CACHE_SIZE);
        if (ret <= 0)
            break;

        cache->offset = cache_offset;
        cache->size   = ret;
        dso_cache__insert(&dso->cache, cache);

        ret = dso_cache__memcpy(cache, offset, data, size);

    } while (0);

    if (ret <= 0)
        free(cache);

    close(fd);
    return ret;
}

static ssize_t dso_cache_read(struct dso *dso, struct machine *machine,
                  u64 offset, u8 *data, ssize_t size)
{
    struct dso_cache *cache;

    cache = dso_cache__find(&dso->cache, offset);
    if (cache)
        return dso_cache__memcpy(cache, offset, data, size);
    else
        return dso_cache__read(dso, machine, offset, data, size);
}

ssize_t dso__data_read_offset(struct dso *dso, struct machine *machine,
                  u64 offset, u8 *data, ssize_t size)
{
    ssize_t r = 0;
    u8 *p = data;

    do {
        ssize_t ret;

        ret = dso_cache_read(dso, machine, offset, p, size);
        if (ret < 0)
            return ret;

        /* Reached EOF, return what we have. */
        if (!ret)
            break;

        BUG_ON(ret > size);

        r      += ret;
        p      += ret;
        offset += ret;
        size   -= ret;

    } while (size);

    return r;
}

ssize_t dso__data_read_addr(struct dso *dso, struct map *map,
                struct machine *machine, u64 addr,
                u8 *data, ssize_t size)
{
    u64 offset = map->map_ip(map, addr);
    return dso__data_read_offset(dso, machine, offset, data, size);
}