#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 "machine.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 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);
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,
        .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)

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;
}

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);
}

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 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)
{
        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]);
}

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;
}

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;
}

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;
}

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;

        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;

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

        /* 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;
}

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) {
                        dso->lname_alloc = 1;
                        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]));
                        dso->lname_alloc = 1;
                        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));
                        dso->lname_alloc = 1;
                        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;
}

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;
}

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;
}