#include <dirent.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <linux/kernel.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/param.h>
#include <fcntl.h>
#include <unistd.h>
#include <inttypes.h>
#include "annotate.h"
#include "build-id.h"
#include "util.h"
#include "debug.h"
#include "machine.h"
#include "symbol.h"
#include "strlist.h"
#include "intlist.h"
#include "header.h"
#include "path.h"
#include "sane_ctype.h"

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

static int dso__load_kernel_sym(struct dso *dso, struct map *map);
static int dso__load_guest_kernel_sym(struct dso *dso, struct map *map);
static bool symbol__is_idle(const char *name);

int vmlinux_path__nr_entries;
char **vmlinux_path;

struct symbol_conf symbol_conf = {
        .use_modules            = true,
        .try_vmlinux_path       = true,
        .annotate_src           = true,
        .demangle               = true,
        .demangle_kernel        = false,
        .cumulate_callchain     = true,
        .show_hist_headers      = true,
        .symfs                  = "",
        .event_group            = true,
};

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__GUEST_KMODULE_COMP,
        DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE,
        DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP,
        DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
        DSO_BINARY_TYPE__NOT_FOUND,
};

#define DSO_BINARY_TYPE__SYMTAB_CNT ARRAY_SIZE(binary_type_symtab)

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;
}

int __weak arch__compare_symbol_names(const char *namea, const char *nameb)
{
        return strcmp(namea, nameb);
}

int __weak arch__compare_symbol_names_n(const char *namea, const char *nameb,
                                        unsigned int n)
{
        return strncmp(namea, nameb, n);
}

int __weak arch__choose_best_symbol(struct symbol *syma,
                                    struct symbol *symb __maybe_unused)
{
        /* Avoid "SyS" kernel syscall aliases */
        if (strlen(syma->name) >= 3 && !strncmp(syma->name, "SyS", 3))
                return SYMBOL_B;
        if (strlen(syma->name) >= 10 && !strncmp(syma->name, "compat_SyS", 10))
                return SYMBOL_B;

        return SYMBOL_A;
}

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

        /* 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;

        /* Choose the symbol with the longest name */
        na = strlen(syma->name);
        nb = strlen(symb->name);
        if (na > nb)
                return SYMBOL_A;
        else if (na < nb)
                return SYMBOL_B;

        return arch__choose_best_symbol(syma, symb);
}

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

        if (symbol_conf.allow_aliases)
                return;

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

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;
        }

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

void __map_groups__fixup_end(struct map_groups *mg, enum map_type type)
{
        struct maps *maps = &mg->maps[type];
        struct map *next, *curr;

        pthread_rwlock_wrlock(&maps->lock);

        curr = maps__first(maps);
        if (curr == NULL)
                goto out_unlock;

        for (next = map__next(curr); next; next = map__next(curr)) {
                curr->end = next->start;
                curr = next;
        }

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

out_unlock:
        pthread_rwlock_unlock(&maps->lock);
}

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) {
                if (symbol_conf.init_annotation) {
                        struct annotation *notes = (void *)sym;
                        pthread_mutex_init(&notes->lock, NULL);
                }
                sym = ((void *)sym) + symbol_conf.priv_size;
        }

        sym->start   = start;
        sym->end     = len ? start + len : 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);
}

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

        if (kernel) {
                const char *name = sym->name;
                /*
                 * ppc64 uses function descriptors and appends a '.' to the
                 * start of every instruction address. Remove it.
                 */
                if (name[0] == '.')
                        name++;
                sym->idle = symbol__is_idle(name);
        }

        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);
}

void symbols__insert(struct rb_root *symbols, struct symbol *sym)
{
        __symbols__insert(symbols, sym, false);
}

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 || (ip == s->end && ip != s->start))
                        n = n->rb_right;
                else
                        return s;
        }

        return NULL;
}

static struct symbol *symbols__first(struct rb_root *symbols)
{
        struct rb_node *n = rb_first(symbols);

        if (n)
                return rb_entry(n, struct symbol, rb_node);

        return NULL;
}

static struct symbol *symbols__last(struct rb_root *symbols)
{
        struct rb_node *n = rb_last(symbols);

        if (n)
                return rb_entry(n, struct symbol, rb_node);

        return NULL;
}

static struct symbol *symbols__next(struct symbol *sym)
{
        struct rb_node *n = rb_next(&sym->rb_node);

        if (n)
                return rb_entry(n, struct symbol, rb_node);

        return NULL;
}

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);
        }
}

int symbol__match_symbol_name(const char *name, const char *str,
                              enum symbol_tag_include includes)
{
        const char *versioning;

        if (includes == SYMBOL_TAG_INCLUDE__DEFAULT_ONLY &&
            (versioning = strstr(name, "@@"))) {
                int len = strlen(str);

                if (len < versioning - name)
                        len = versioning - name;

                return arch__compare_symbol_names_n(name, str, len);
        } else
                return arch__compare_symbol_names(name, str);
}

static struct symbol *symbols__find_by_name(struct rb_root *symbols,
                                            const char *name,
                                            enum symbol_tag_include includes)
{
        struct rb_node *n;
        struct symbol_name_rb_node *s = NULL;

        if (symbols == NULL)
                return NULL;

        n = symbols->rb_node;

        while (n) {
                int cmp;

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

                if (cmp > 0)
                        n = n->rb_left;
                else if (cmp < 0)
                        n = n->rb_right;
                else
                        break;
        }

        if (n == NULL)
                return NULL;

        if (includes != SYMBOL_TAG_INCLUDE__DEFAULT_ONLY)
                /* return first symbol that has same name (if any) */
                for (n = rb_prev(n); n; n = rb_prev(n)) {
                        struct symbol_name_rb_node *tmp;

                        tmp = rb_entry(n, struct symbol_name_rb_node, rb_node);
                        if (arch__compare_symbol_names(tmp->sym.name, s->sym.name))
                                break;

                        s = tmp;
                }

        return &s->sym;
}

void dso__reset_find_symbol_cache(struct dso *dso)
{
        enum map_type type;

        for (type = MAP__FUNCTION; type <= MAP__VARIABLE; ++type) {
                dso->last_find_result[type].addr   = 0;
                dso->last_find_result[type].symbol = NULL;
        }
}

void dso__insert_symbol(struct dso *dso, enum map_type type, struct symbol *sym)
{
        __symbols__insert(&dso->symbols[type], sym, dso->kernel);

        /* update the symbol cache if necessary */
        if (dso->last_find_result[type].addr >= sym->start &&
            (dso->last_find_result[type].addr < sym->end ||
            sym->start == sym->end)) {
                dso->last_find_result[type].symbol = sym;
        }
}

struct symbol *dso__find_symbol(struct dso *dso,
                                enum map_type type, u64 addr)
{
        if (dso->last_find_result[type].addr != addr || dso->last_find_result[type].symbol == NULL) {
                dso->last_find_result[type].addr   = addr;
                dso->last_find_result[type].symbol = symbols__find(&dso->symbols[type], addr);
        }

        return dso->last_find_result[type].symbol;
}

struct symbol *dso__first_symbol(struct dso *dso, enum map_type type)
{
        return symbols__first(&dso->symbols[type]);
}

struct symbol *dso__last_symbol(struct dso *dso, enum map_type type)
{
        return symbols__last(&dso->symbols[type]);
}

struct symbol *dso__next_symbol(struct symbol *sym)
{
        return symbols__next(sym);
}

struct symbol *symbol__next_by_name(struct symbol *sym)
{
        struct symbol_name_rb_node *s = container_of(sym, struct symbol_name_rb_node, sym);
        struct rb_node *n = rb_next(&s->rb_node);

        return n ? &rb_entry(n, struct symbol_name_rb_node, rb_node)->sym : NULL;
}

 /*
  * Teturns first symbol that matched with @name.
  */
struct symbol *dso__find_symbol_by_name(struct dso *dso, enum map_type type,
                                        const char *name)
{
        struct symbol *s = symbols__find_by_name(&dso->symbol_names[type], name,
                                                 SYMBOL_TAG_INCLUDE__NONE);
        if (!s)
                s = symbols__find_by_name(&dso->symbol_names[type], name,
                                          SYMBOL_TAG_INCLUDE__DEFAULT_ONLY);
        return s;
}

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 modules__parse(const char *filename, void *arg,
                   int (*process_module)(void *arg, const char *name,
                                         u64 start))
{
        char *line = NULL;
        size_t n;
        FILE *file;
        int err = 0;

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

        while (1) {
                char name[PATH_MAX];
                u64 start;
                char *sep;
                ssize_t line_len;

                line_len = getline(&line, &n, file);
                if (line_len < 0) {
                        if (feof(file))
                                break;
                        err = -1;
                        goto out;
                }

                if (!line) {
                        err = -1;
                        goto out;
                }

                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';

                scnprintf(name, sizeof(name), "[%s]", line);

                err = process_module(arg, name, start);
                if (err)
                        break;
        }
out:
        free(line);
        fclose(file);
        return err;
}

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

/*
 * These are symbols in the kernel image, so make sure that
 * sym is from a kernel DSO.
 */
static bool symbol__is_idle(const char *name)
{
        const char * const idle_symbols[] = {
                "cpu_idle",
                "cpu_startup_entry",
                "intel_idle",
                "default_idle",
                "native_safe_halt",
                "enter_idle",
                "exit_idle",
                "mwait_idle",
                "mwait_idle_with_hints",
                "poll_idle",
                "ppc64_runlatch_off",
                "pseries_dedicated_idle_sleep",
                NULL
        };
        int i;

        for (i = 0; idle_symbols[i]; i++) {
                if (!strcmp(idle_symbols[i], name))
                        return true;
        }

        return false;
}

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_binding(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, !strchr(name, '['));

        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);
}

static int dso__split_kallsyms_for_kcore(struct dso *dso, struct map *map)
{
        struct map_groups *kmaps = map__kmaps(map);
        struct map *curr_map;
        struct symbol *pos;
        int count = 0;
        struct rb_root old_root = dso->symbols[map->type];
        struct rb_root *root = &dso->symbols[map->type];
        struct rb_node *next = rb_first(root);

        if (!kmaps)
                return -1;

        *root = RB_ROOT;

        while (next) {
                char *module;

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

                rb_erase_init(&pos->rb_node, &old_root);

                module = strchr(pos->name, '\t');
                if (module)
                        *module = '\0';

                curr_map = map_groups__find(kmaps, map->type, pos->start);

                if (!curr_map) {
                        symbol__delete(pos);
                        continue;
                }

                pos->start -= curr_map->start - curr_map->pgoff;
                if (pos->end)
                        pos->end -= curr_map->start - curr_map->pgoff;
                symbols__insert(&curr_map->dso->symbols[curr_map->type], pos);
                ++count;
        }

        /* Symbols have been adjusted */
        dso->adjust_symbols = 1;

        return count;
}

/*
 * 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, u64 delta)
{
        struct map_groups *kmaps = map__kmaps(map);
        struct machine *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;

        if (!kmaps)
                return -1;

        machine = kmaps->machine;

        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 (delta) {
                                /* Kernel was relocated at boot time */
                                pos->start -= delta;
                                pos->end -= delta;
                        }

                        if (count == 0) {
                                curr_map = map;
                                goto add_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__put(ndso);
                                return -1;
                        }

                        curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
                        map_groups__insert(kmaps, curr_map);
                        ++kernel_range;
                } else if (delta) {
                        /* Kernel was relocated at boot time */
                        pos->start -= delta;
                        pos->end -= delta;
                }
add_symbol:
                if (curr_map != map) {
                        rb_erase(&pos->rb_node, root);
                        symbols__insert(&curr_map->dso->symbols[curr_map->type], pos);
                        ++moved;
                } else
                        ++count;

                continue;
discard_symbol:
                rb_erase(&pos->rb_node, root);
                symbol__delete(pos);
        }

        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;
}

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;
}

struct module_info {
        struct rb_node rb_node;
        char *name;
        u64 start;
};

static void add_module(struct module_info *mi, struct rb_root *modules)
{
        struct rb_node **p = &modules->rb_node;
        struct rb_node *parent = NULL;
        struct module_info *m;

        while (*p != NULL) {
                parent = *p;
                m = rb_entry(parent, struct module_info, rb_node);
                if (strcmp(mi->name, m->name) < 0)
                        p = &(*p)->rb_left;
                else
                        p = &(*p)->rb_right;
        }
        rb_link_node(&mi->rb_node, parent, p);
        rb_insert_color(&mi->rb_node, modules);
}

static void delete_modules(struct rb_root *modules)
{
        struct module_info *mi;
        struct rb_node *next = rb_first(modules);

        while (next) {
                mi = rb_entry(next, struct module_info, rb_node);
                next = rb_next(&mi->rb_node);
                rb_erase(&mi->rb_node, modules);
                zfree(&mi->name);
                free(mi);
        }
}

static struct module_info *find_module(const char *name,
                                       struct rb_root *modules)
{
        struct rb_node *n = modules->rb_node;

        while (n) {
                struct module_info *m;
                int cmp;

                m = rb_entry(n, struct module_info, rb_node);
                cmp = strcmp(name, m->name);
                if (cmp < 0)
                        n = n->rb_left;
                else if (cmp > 0)
                        n = n->rb_right;
                else
                        return m;
        }

        return NULL;
}

static int __read_proc_modules(void *arg, const char *name, u64 start)
{
        struct rb_root *modules = arg;
        struct module_info *mi;

        mi = zalloc(sizeof(struct module_info));
        if (!mi)
                return -ENOMEM;

        mi->name = strdup(name);
        mi->start = start;

        if (!mi->name) {
                free(mi);
                return -ENOMEM;
        }

        add_module(mi, modules);

        return 0;
}

static int read_proc_modules(const char *filename, struct rb_root *modules)
{
        if (symbol__restricted_filename(filename, "/proc/modules"))
                return -1;

        if (modules__parse(filename, modules, __read_proc_modules)) {
                delete_modules(modules);
                return -1;
        }

        return 0;
}

int compare_proc_modules(const char *from, const char *to)
{
        struct rb_root from_modules = RB_ROOT;
        struct rb_root to_modules = RB_ROOT;
        struct rb_node *from_node, *to_node;
        struct module_info *from_m, *to_m;
        int ret = -1;

        if (read_proc_modules(from, &from_modules))
                return -1;

        if (read_proc_modules(to, &to_modules))
                goto out_delete_from;

        from_node = rb_first(&from_modules);
        to_node = rb_first(&to_modules);
        while (from_node) {
                if (!to_node)
                        break;

                from_m = rb_entry(from_node, struct module_info, rb_node);
                to_m = rb_entry(to_node, struct module_info, rb_node);

                if (from_m->start != to_m->start ||
                    strcmp(from_m->name, to_m->name))
                        break;

                from_node = rb_next(from_node);
                to_node = rb_next(to_node);
        }

        if (!from_node && !to_node)
                ret = 0;

        delete_modules(&to_modules);
out_delete_from:
        delete_modules(&from_modules);

        return ret;
}

static int do_validate_kcore_modules(const char *filename, struct map *map,
                                  struct map_groups *kmaps)
{
        struct rb_root modules = RB_ROOT;
        struct map *old_map;
        int err;

        err = read_proc_modules(filename, &modules);
        if (err)
                return err;

        old_map = map_groups__first(kmaps, map->type);
        while (old_map) {
                struct map *next = map_groups__next(old_map);
                struct module_info *mi;

                if (old_map == map || old_map->start == map->start) {
                        /* The kernel map */
                        old_map = next;
                        continue;
                }

                /* Module must be in memory at the same address */
                mi = find_module(old_map->dso->short_name, &modules);
                if (!mi || mi->start != old_map->start) {
                        err = -EINVAL;
                        goto out;
                }

                old_map = next;
        }
out:
        delete_modules(&modules);
        return err;
}

/*
 * If kallsyms is referenced by name then we look for filename in the same
 * directory.
 */
static bool filename_from_kallsyms_filename(char *filename,
                                            const char *base_name,
                                            const char *kallsyms_filename)
{
        char *name;

        strcpy(filename, kallsyms_filename);
        name = strrchr(filename, '/');
        if (!name)
                return false;

        name += 1;

        if (!strcmp(name, "kallsyms")) {
                strcpy(name, base_name);
                return true;
        }

        return false;
}

static int validate_kcore_modules(const char *kallsyms_filename,
                                  struct map *map)
{
        struct map_groups *kmaps = map__kmaps(map);
        char modules_filename[PATH_MAX];

        if (!kmaps)
                return -EINVAL;

        if (!filename_from_kallsyms_filename(modules_filename, "modules",
                                             kallsyms_filename))
                return -EINVAL;

        if (do_validate_kcore_modules(modules_filename, map, kmaps))
                return -EINVAL;

        return 0;
}

static int validate_kcore_addresses(const char *kallsyms_filename,
                                    struct map *map)
{
        struct kmap *kmap = map__kmap(map);

        if (!kmap)
                return -EINVAL;

        if (kmap->ref_reloc_sym && kmap->ref_reloc_sym->name) {
                u64 start;

                if (kallsyms__get_function_start(kallsyms_filename,
                                                 kmap->ref_reloc_sym->name, &start))
                        return -ENOENT;
                if (start != kmap->ref_reloc_sym->addr)
                        return -EINVAL;
        }

        return validate_kcore_modules(kallsyms_filename, map);
}

struct kcore_mapfn_data {
        struct dso *dso;
        enum map_type type;
        struct list_head maps;
};

static int kcore_mapfn(u64 start, u64 len, u64 pgoff, void *data)
{
        struct kcore_mapfn_data *md = data;
        struct map *map;

        map = map__new2(start, md->dso, md->type);
        if (map == NULL)
                return -ENOMEM;

        map->end = map->start + len;
        map->pgoff = pgoff;

        list_add(&map->node, &md->maps);

        return 0;
}

static int dso__load_kcore(struct dso *dso, struct map *map,
                           const char *kallsyms_filename)
{
        struct map_groups *kmaps = map__kmaps(map);
        struct machine *machine;
        struct kcore_mapfn_data md;
        struct map *old_map, *new_map, *replacement_map = NULL;
        bool is_64_bit;
        int err, fd;
        char kcore_filename[PATH_MAX];
        struct symbol *sym;

        if (!kmaps)
                return -EINVAL;

        machine = kmaps->machine;

        /* This function requires that the map is the kernel map */
        if (map != machine->vmlinux_maps[map->type])
                return -EINVAL;

        if (!filename_from_kallsyms_filename(kcore_filename, "kcore",
                                             kallsyms_filename))
                return -EINVAL;

        /* Modules and kernel must be present at their original addresses */
        if (validate_kcore_addresses(kallsyms_filename, map))
                return -EINVAL;

        md.dso = dso;
        md.type = map->type;
        INIT_LIST_HEAD(&md.maps);

        fd = open(kcore_filename, O_RDONLY);
        if (fd < 0) {
                pr_debug("Failed to open %s. Note /proc/kcore requires CAP_SYS_RAWIO capability to access.\n",
                         kcore_filename);
                return -EINVAL;
        }

        /* Read new maps into temporary lists */
        err = file__read_maps(fd, md.type == MAP__FUNCTION, kcore_mapfn, &md,
                              &is_64_bit);
        if (err)
                goto out_err;
        dso->is_64_bit = is_64_bit;

        if (list_empty(&md.maps)) {
                err = -EINVAL;
                goto out_err;
        }

        /* Remove old maps */
        old_map = map_groups__first(kmaps, map->type);
        while (old_map) {
                struct map *next = map_groups__next(old_map);

                if (old_map != map)
                        map_groups__remove(kmaps, old_map);
                old_map = next;
        }

        /* Find the kernel map using the first symbol */
        sym = dso__first_symbol(dso, map->type);
        list_for_each_entry(new_map, &md.maps, node) {
                if (sym && sym->start >= new_map->start &&
                    sym->start < new_map->end) {
                        replacement_map = new_map;
                        break;
                }
        }

        if (!replacement_map)
                replacement_map = list_entry(md.maps.next, struct map, node);

        /* Add new maps */
        while (!list_empty(&md.maps)) {
                new_map = list_entry(md.maps.next, struct map, node);
                list_del_init(&new_map->node);
                if (new_map == replacement_map) {
                        map->start      = new_map->start;
                        map->end        = new_map->end;
                        map->pgoff      = new_map->pgoff;
                        map->map_ip     = new_map->map_ip;
                        map->unmap_ip   = new_map->unmap_ip;
                        /* Ensure maps are correctly ordered */
                        map__get(map);
                        map_groups__remove(kmaps, map);
                        map_groups__insert(kmaps, map);
                        map__put(map);
                } else {
                        map_groups__insert(kmaps, new_map);
                }

                map__put(new_map);
        }

        /*
         * Set the data type and long name so that kcore can be read via
         * dso__data_read_addr().
         */
        if (dso->kernel == DSO_TYPE_GUEST_KERNEL)
                dso->binary_type = DSO_BINARY_TYPE__GUEST_KCORE;
        else
                dso->binary_type = DSO_BINARY_TYPE__KCORE;
        dso__set_long_name(dso, strdup(kcore_filename), true);

        close(fd);

        if (map->type == MAP__FUNCTION)
                pr_debug("Using %s for kernel object code\n", kcore_filename);
        else
                pr_debug("Using %s for kernel data\n", kcore_filename);

        return 0;

out_err:
        while (!list_empty(&md.maps)) {
                map = list_entry(md.maps.next, struct map, node);
                list_del_init(&map->node);
                map__put(map);
        }
        close(fd);
        return -EINVAL;
}

/*
 * If the kernel is relocated at boot time, kallsyms won't match.  Compute the
 * delta based on the relocation reference symbol.
 */
static int kallsyms__delta(struct map *map, const char *filename, u64 *delta)
{
        struct kmap *kmap = map__kmap(map);
        u64 addr;

        if (!kmap)
                return -1;

        if (!kmap->ref_reloc_sym || !kmap->ref_reloc_sym->name)
                return 0;

        if (kallsyms__get_function_start(filename, kmap->ref_reloc_sym->name, &addr))
                return -1;

        *delta = addr - kmap->ref_reloc_sym->addr;
        return 0;
}

int __dso__load_kallsyms(struct dso *dso, const char *filename,
                         struct map *map, bool no_kcore)
{
        u64 delta = 0;

        if (symbol__restricted_filename(filename, "/proc/kallsyms"))
                return -1;

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

        if (kallsyms__delta(map, filename, &delta))
                return -1;

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

        if (!no_kcore && !dso__load_kcore(dso, map, filename))
                return dso__split_kallsyms_for_kcore(dso, map);
        else
                return dso__split_kallsyms(dso, map, delta);
}

int dso__load_kallsyms(struct dso *dso, const char *filename,
                       struct map *map)
{
        return __dso__load_kallsyms(dso, filename, map, false);
}

static int dso__load_perf_map(struct dso *dso, struct map *map)
{
        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;

                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;
}

static bool dso__is_compatible_symtab_type(struct dso *dso, bool kmod,
                                           enum dso_binary_type type)
{
        switch (type) {
        case DSO_BINARY_TYPE__JAVA_JIT:
        case DSO_BINARY_TYPE__DEBUGLINK:
        case DSO_BINARY_TYPE__SYSTEM_PATH_DSO:
        case DSO_BINARY_TYPE__FEDORA_DEBUGINFO:
        case DSO_BINARY_TYPE__UBUNTU_DEBUGINFO:
        case DSO_BINARY_TYPE__BUILDID_DEBUGINFO:
        case DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO:
                return !kmod && dso->kernel == DSO_TYPE_USER;

        case DSO_BINARY_TYPE__KALLSYMS:
        case DSO_BINARY_TYPE__VMLINUX:
        case DSO_BINARY_TYPE__KCORE:
                return dso->kernel == DSO_TYPE_KERNEL;

        case DSO_BINARY_TYPE__GUEST_KALLSYMS:
        case DSO_BINARY_TYPE__GUEST_VMLINUX:
        case DSO_BINARY_TYPE__GUEST_KCORE:
                return dso->kernel == DSO_TYPE_GUEST_KERNEL;

        case DSO_BINARY_TYPE__GUEST_KMODULE:
        case DSO_BINARY_TYPE__GUEST_KMODULE_COMP:
        case DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE:
        case DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP:
                /*
                 * kernel modules know their symtab type - it's set when
                 * creating a module dso in machine__findnew_module_map().
                 */
                return kmod && dso->symtab_type == type;

        case DSO_BINARY_TYPE__BUILD_ID_CACHE:
                return true;

        case DSO_BINARY_TYPE__NOT_FOUND:
        default:
                return false;
        }
}

int dso__load(struct dso *dso, struct map *map)
{
        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;
        bool kmod;
        unsigned char build_id[BUILD_ID_SIZE];

        pthread_mutex_lock(&dso->lock);

        /* check again under the dso->lock */
        if (dso__loaded(dso, map->type)) {
                ret = 1;
                goto out;
        }

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

                goto out;
        }

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

        dso->adjust_symbols = 0;

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

                if (lstat(dso->name, &st) < 0)
                        goto out;

                if (!symbol_conf.force && st.st_uid && (st.st_uid != geteuid())) {
                        pr_warning("File %s not owned by current user or root, "
                                   "ignoring it (use -f to override).\n", dso->name);
                        goto out;
                }

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

        if (machine)
                root_dir = machine->root_dir;

        name = malloc(PATH_MAX);
        if (!name)
                goto out;

        kmod = dso->symtab_type == DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE ||
                dso->symtab_type == DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP ||
                dso->symtab_type == DSO_BINARY_TYPE__GUEST_KMODULE ||
                dso->symtab_type == DSO_BINARY_TYPE__GUEST_KMODULE_COMP;


        /*
         * Read the build id if possible. This is required for
         * DSO_BINARY_TYPE__BUILDID_DEBUGINFO to work
         */
        if (!dso->has_build_id &&
            is_regular_file(dso->long_name)) {
            __symbol__join_symfs(name, PATH_MAX, dso->long_name);
            if (filename__read_build_id(name, build_id, BUILD_ID_SIZE) > 0)
                dso__set_build_id(dso, build_id);
        }

        /*
         * 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__is_compatible_symtab_type(dso, kmod, symtab_type))
                        continue;

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

                if (!is_regular_file(name))
                        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 (!dso->symsrc_filename)
                                dso->symsrc_filename = strdup(name);
                }

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

                if (next_slot) {
                        ss_pos++;

                        if (syms_ss && runtime_ss)
                                break;
                } else {
                        symsrc__destroy(ss);
                }

        }

        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, kmod);
        else
                ret = -1;

        if (ret > 0) {
                int nr_plt;

                nr_plt = dso__synthesize_plt_symbols(dso, runtime_ss, map);
                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)
                ret = 0;
out:
        dso__set_loaded(dso, map->type);
        pthread_mutex_unlock(&dso->lock);

        return ret;
}

struct map *map_groups__find_by_name(struct map_groups *mg,
                                     enum map_type type, const char *name)
{
        struct maps *maps = &mg->maps[type];
        struct map *map;

        pthread_rwlock_rdlock(&maps->lock);

        for (map = maps__first(maps); map; map = map__next(map)) {
                if (map->dso && strcmp(map->dso->short_name, name) == 0)
                        goto out_unlock;
        }

        map = NULL;

out_unlock:
        pthread_rwlock_unlock(&maps->lock);
        return map;
}

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

        if (vmlinux[0] == '/')
                snprintf(symfs_vmlinux, sizeof(symfs_vmlinux), "%s", vmlinux);
        else
                symbol__join_symfs(symfs_vmlinux, 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, 0);
        symsrc__destroy(&ss);

        if (err > 0) {
                if (dso->kernel == DSO_TYPE_GUEST_KERNEL)
                        dso->binary_type = DSO_BINARY_TYPE__GUEST_VMLINUX;
                else
                        dso->binary_type = DSO_BINARY_TYPE__VMLINUX;
                dso__set_long_name(dso, vmlinux, vmlinux_allocated);
                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)
{
        int i, err = 0;
        char *filename = NULL;

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

        for (i = 0; i < vmlinux_path__nr_entries; ++i) {
                err = dso__load_vmlinux(dso, map, vmlinux_path[i], false);
                if (err > 0)
                        goto out;
        }

        if (!symbol_conf.ignore_vmlinux_buildid)
                filename = dso__build_id_filename(dso, NULL, 0);
        if (filename != NULL) {
                err = dso__load_vmlinux(dso, map, filename, true);
                if (err > 0)
                        goto out;
                free(filename);
        }
out:
        return err;
}

static bool visible_dir_filter(const char *name, struct dirent *d)
{
        if (d->d_type != DT_DIR)
                return false;
        return lsdir_no_dot_filter(name, d);
}

static int find_matching_kcore(struct map *map, char *dir, size_t dir_sz)
{
        char kallsyms_filename[PATH_MAX];
        int ret = -1;
        struct strlist *dirs;
        struct str_node *nd;

        dirs = lsdir(dir, visible_dir_filter);
        if (!dirs)
                return -1;

        strlist__for_each_entry(nd, dirs) {
                scnprintf(kallsyms_filename, sizeof(kallsyms_filename),
                          "%s/%s/kallsyms", dir, nd->s);
                if (!validate_kcore_addresses(kallsyms_filename, map)) {
                        strlcpy(dir, kallsyms_filename, dir_sz);
                        ret = 0;
                        break;
                }
        }

        strlist__delete(dirs);

        return ret;
}

/*
 * Use open(O_RDONLY) to check readability directly instead of access(R_OK)
 * since access(R_OK) only checks with real UID/GID but open() use effective
 * UID/GID and actual capabilities (e.g. /proc/kcore requires CAP_SYS_RAWIO).
 */
static bool filename__readable(const char *file)
{
        int fd = open(file, O_RDONLY);
        if (fd < 0)
                return false;
        close(fd);
        return true;
}

static char *dso__find_kallsyms(struct dso *dso, struct map *map)
{
        u8 host_build_id[BUILD_ID_SIZE];
        char sbuild_id[SBUILD_ID_SIZE];
        bool is_host = false;
        char path[PATH_MAX];

        if (!dso->has_build_id) {
                /*
                 * Last resort, if we don't have a build-id and couldn't find
                 * any vmlinux file, try the running kernel kallsyms table.
                 */
                goto proc_kallsyms;
        }

        if (sysfs__read_build_id("/sys/kernel/notes", host_build_id,
                                 sizeof(host_build_id)) == 0)
                is_host = dso__build_id_equal(dso, host_build_id);

        /* Try a fast path for /proc/kallsyms if possible */
        if (is_host) {
                /*
                 * Do not check the build-id cache, unless we know we cannot use
                 * /proc/kcore or module maps don't match to /proc/kallsyms.
                 * To check readability of /proc/kcore, do not use access(R_OK)
                 * since /proc/kcore requires CAP_SYS_RAWIO to read and access
                 * can't check it.
                 */
                if (filename__readable("/proc/kcore") &&
                    !validate_kcore_addresses("/proc/kallsyms", map))
                        goto proc_kallsyms;
        }

        build_id__sprintf(dso->build_id, sizeof(dso->build_id), sbuild_id);

        /* Find kallsyms in build-id cache with kcore */
        scnprintf(path, sizeof(path), "%s/%s/%s",
                  buildid_dir, DSO__NAME_KCORE, sbuild_id);

        if (!find_matching_kcore(map, path, sizeof(path)))
                return strdup(path);

        /* Use current /proc/kallsyms if possible */
        if (is_host) {
proc_kallsyms:
                return strdup("/proc/kallsyms");
        }

        /* Finally, find a cache of kallsyms */
        if (!build_id_cache__kallsyms_path(sbuild_id, path, sizeof(path))) {
                pr_err("No kallsyms or vmlinux with build-id %s was found\n",
                       sbuild_id);
                return NULL;
        }

        return strdup(path);
}

static int dso__load_kernel_sym(struct dso *dso, struct map *map)
{
        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.ignore_vmlinux && symbol_conf.vmlinux_name != NULL) {
                return dso__load_vmlinux(dso, map, symbol_conf.vmlinux_name, false);
        }

        if (!symbol_conf.ignore_vmlinux && vmlinux_path != NULL) {
                err = dso__load_vmlinux_path(dso, map);
                if (err > 0)
                        return err;
        }

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

        kallsyms_allocated_filename = dso__find_kallsyms(dso, map);
        if (!kallsyms_allocated_filename)
                return -1;

        kallsyms_filename = kallsyms_allocated_filename;

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

        if (err > 0 && !dso__is_kcore(dso)) {
                dso->binary_type = DSO_BINARY_TYPE__KALLSYMS;
                dso__set_long_name(dso, DSO__NAME_KALLSYMS, false);
                map__fixup_start(map);
                map__fixup_end(map);
        }

        return err;
}

static int dso__load_guest_kernel_sym(struct dso *dso, struct map *map)
{
        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,
                                                false);
                        return err;
                }

                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);
        if (err > 0)
                pr_debug("Using %s for symbols\n", kallsyms_filename);
        if (err > 0 && !dso__is_kcore(dso)) {
                dso->binary_type = DSO_BINARY_TYPE__GUEST_KALLSYMS;
                machine__mmap_name(machine, path, sizeof(path));
                dso__set_long_name(dso, strdup(path), true);
                map__fixup_start(map);
                map__fixup_end(map);
        }

        return err;
}

static void vmlinux_path__exit(void)
{
        while (--vmlinux_path__nr_entries >= 0)
                zfree(&vmlinux_path[vmlinux_path__nr_entries]);
        vmlinux_path__nr_entries = 0;

        zfree(&vmlinux_path);
}

static const char * const vmlinux_paths[] = {
        "vmlinux",
        "/boot/vmlinux"
};

static const char * const vmlinux_paths_upd[] = {
        "/boot/vmlinux-%s",
        "/usr/lib/debug/boot/vmlinux-%s",
        "/lib/modules/%s/build/vmlinux",
        "/usr/lib/debug/lib/modules/%s/vmlinux",
        "/usr/lib/debug/boot/vmlinux-%s.debug"
};

static int vmlinux_path__add(const char *new_entry)
{
        vmlinux_path[vmlinux_path__nr_entries] = strdup(new_entry);
        if (vmlinux_path[vmlinux_path__nr_entries] == NULL)
                return -1;
        ++vmlinux_path__nr_entries;

        return 0;
}

static int vmlinux_path__init(struct perf_env *env)
{
        struct utsname uts;
        char bf[PATH_MAX];
        char *kernel_version;
        unsigned int i;

        vmlinux_path = malloc(sizeof(char *) * (ARRAY_SIZE(vmlinux_paths) +
                              ARRAY_SIZE(vmlinux_paths_upd)));
        if (vmlinux_path == NULL)
                return -1;

        for (i = 0; i < ARRAY_SIZE(vmlinux_paths); i++)
                if (vmlinux_path__add(vmlinux_paths[i]) < 0)
                        goto out_fail;

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

        if (env) {
                kernel_version = env->os_release;
        } else {
                if (uname(&uts) < 0)
                        goto out_fail;

                kernel_version = uts.release;
        }

        for (i = 0; i < ARRAY_SIZE(vmlinux_paths_upd); i++) {
                snprintf(bf, sizeof(bf), vmlinux_paths_upd[i], kernel_version);
                if (vmlinux_path__add(bf) < 0)
                        goto out_fail;
        }

        return 0;

out_fail:
        vmlinux_path__exit();
        return -1;
}

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

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

        symbol_conf.has_filter = true;
        return 0;
}

int setup_intlist(struct intlist **list, const char *list_str,
                  const char *list_name)
{
        if (list_str == NULL)
                return 0;

        *list = intlist__new(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;
        FILE *fp = fopen("/proc/sys/kernel/kptr_restrict", "r");

        if (fp != NULL) {
                char line[8];

                if (fgets(line, sizeof(line), fp) != NULL)

                        value = ((geteuid() != 0) || (getuid() != 0)) ?
                                        (atoi(line) != 0) :
                                        (atoi(line) == 2);

                fclose(fp);
        }

        return value;
}

int symbol__annotation_init(void)
{
        if (symbol_conf.initialized) {
                pr_err("Annotation needs to be init before symbol__init()\n");
                return -1;
        }

        if (symbol_conf.init_annotation) {
                pr_warning("Annotation being initialized multiple times\n");
                return 0;
        }

        symbol_conf.priv_size += sizeof(struct annotation);
        symbol_conf.init_annotation = true;
        return 0;
}

int symbol__init(struct perf_env *env)
{
        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(env) < 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_intlist(&symbol_conf.pid_list,
                       symbol_conf.pid_list_str, "pid") < 0)
                goto out_free_comm_list;

        if (setup_intlist(&symbol_conf.tid_list,
                       symbol_conf.tid_list_str, "tid") < 0)
                goto out_free_pid_list;

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

        if (setup_list(&symbol_conf.bt_stop_list,
                       symbol_conf.bt_stop_list_str, "symbol") < 0)
                goto out_free_sym_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_sym_list:
        strlist__delete(symbol_conf.sym_list);
out_free_tid_list:
        intlist__delete(symbol_conf.tid_list);
out_free_pid_list:
        intlist__delete(symbol_conf.pid_list);
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.bt_stop_list);
        strlist__delete(symbol_conf.sym_list);
        strlist__delete(symbol_conf.dso_list);
        strlist__delete(symbol_conf.comm_list);
        intlist__delete(symbol_conf.tid_list);
        intlist__delete(symbol_conf.pid_list);
        vmlinux_path__exit();
        symbol_conf.sym_list = symbol_conf.dso_list = symbol_conf.comm_list = NULL;
        symbol_conf.bt_stop_list = NULL;
        symbol_conf.initialized = false;
}

int symbol__config_symfs(const struct option *opt __maybe_unused,
                         const char *dir, int unset __maybe_unused)
{
        char *bf = NULL;
        int ret;

        symbol_conf.symfs = strdup(dir);
        if (symbol_conf.symfs == NULL)
                return -ENOMEM;

        /* skip the locally configured cache if a symfs is given, and
         * config buildid dir to symfs/.debug
         */
        ret = asprintf(&bf, "%s/%s", dir, ".debug");
        if (ret < 0)
                return -ENOMEM;

        set_buildid_dir(bf);

        free(bf);
        return 0;
}