srcline.c

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// SPDX-License-Identifier: GPL-2.0
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <linux/kernel.h>

#include "util/dso.h"
#include "util/util.h"
#include "util/debug.h"
#include "util/callchain.h"
#include "srcline.h"
#include "string2.h"
#include "symbol.h"

bool srcline_full_filename;

static const char *dso__name(struct dso *dso)
{
    const char *dso_name;

    if (dso->symsrc_filename)
        dso_name = dso->symsrc_filename;
    else
        dso_name = dso->long_name;

    if (dso_name[0] == '[')
        return NULL;

    if (!strncmp(dso_name, "/tmp/perf-", 10))
        return NULL;

    return dso_name;
}

static int inline_list__append(struct symbol *symbol, char *srcline,
                   struct inline_node *node)
{
    struct inline_list *ilist;

    ilist = zalloc(sizeof(*ilist));
    if (ilist == NULL)
        return -1;

    ilist->symbol = symbol;
    ilist->srcline = srcline;

    if (callchain_param.order == ORDER_CALLEE)
        list_add_tail(&ilist->list, &node->val);
    else
        list_add(&ilist->list, &node->val);

    return 0;
}

/* basename version that takes a const input string */
static const char *gnu_basename(const char *path)
{
    const char *base = strrchr(path, '/');

    return base ? base + 1 : path;
}

static char *srcline_from_fileline(const char *file, unsigned int line)
{
    char *srcline;

    if (!file)
        return NULL;

    if (!srcline_full_filename)
        file = gnu_basename(file);

    if (asprintf(&srcline, "%s:%u", file, line) < 0)
        return NULL;

    return srcline;
}

static struct symbol *new_inline_sym(struct dso *dso,
                     struct symbol *base_sym,
                     const char *funcname)
{
    struct symbol *inline_sym;
    char *demangled = NULL;

    if (dso) {
        demangled = dso__demangle_sym(dso, 0, funcname);
        if (demangled)
            funcname = demangled;
    }

    if (base_sym && strcmp(funcname, base_sym->name) == 0) {
        /* reuse the real, existing symbol */
        inline_sym = base_sym;
        /* ensure that we don't alias an inlined symbol, which could
         * lead to double frees in inline_node__delete
         */
        assert(!base_sym->inlined);
    } else {
        /* create a fake symbol for the inline frame */
        inline_sym = symbol__new(base_sym ? base_sym->start : 0,
                     base_sym ? base_sym->end : 0,
                     base_sym ? base_sym->binding : 0,
                     base_sym ? base_sym->type : 0,
                     funcname);
        if (inline_sym)
            inline_sym->inlined = 1;
    }

    free(demangled);

    return inline_sym;
}

#ifdef HAVE_LIBBFD_SUPPORT

/*
 * Implement addr2line using libbfd.
 */
#define PACKAGE "perf"
#include <bfd.h>

struct a2l_data {
    const char  *input;
    u64     addr;

    bool        found;
    const char  *filename;
    const char  *funcname;
    unsigned    line;

    bfd         *abfd;
    asymbol     **syms;
};

static int bfd_error(const char *string)
{
    const char *errmsg;

    errmsg = bfd_errmsg(bfd_get_error());
    fflush(stdout);

    if (string)
        pr_debug("%s: %s\n", string, errmsg);
    else
        pr_debug("%s\n", errmsg);

    return -1;
}

static int slurp_symtab(bfd *abfd, struct a2l_data *a2l)
{
    long storage;
    long symcount;
    asymbol **syms;
    bfd_boolean dynamic = FALSE;

    if ((bfd_get_file_flags(abfd) & HAS_SYMS) == 0)
        return bfd_error(bfd_get_filename(abfd));

    storage = bfd_get_symtab_upper_bound(abfd);
    if (storage == 0L) {
        storage = bfd_get_dynamic_symtab_upper_bound(abfd);
        dynamic = TRUE;
    }
    if (storage < 0L)
        return bfd_error(bfd_get_filename(abfd));

    syms = malloc(storage);
    if (dynamic)
        symcount = bfd_canonicalize_dynamic_symtab(abfd, syms);
    else
        symcount = bfd_canonicalize_symtab(abfd, syms);

    if (symcount < 0) {
        free(syms);
        return bfd_error(bfd_get_filename(abfd));
    }

    a2l->syms = syms;
    return 0;
}

static void find_address_in_section(bfd *abfd, asection *section, void *data)
{
    bfd_vma pc, vma;
    bfd_size_type size;
    struct a2l_data *a2l = data;

    if (a2l->found)
        return;

    if ((bfd_get_section_flags(abfd, section) & SEC_ALLOC) == 0)
        return;

    pc = a2l->addr;
    vma = bfd_get_section_vma(abfd, section);
    size = bfd_get_section_size(section);

    if (pc < vma || pc >= vma + size)
        return;

    a2l->found = bfd_find_nearest_line(abfd, section, a2l->syms, pc - vma,
                       &a2l->filename, &a2l->funcname,
                       &a2l->line);

    if (a2l->filename && !strlen(a2l->filename))
        a2l->filename = NULL;
}

static struct a2l_data *addr2line_init(const char *path)
{
    bfd *abfd;
    struct a2l_data *a2l = NULL;

    abfd = bfd_openr(path, NULL);
    if (abfd == NULL)
        return NULL;

    if (!bfd_check_format(abfd, bfd_object))
        goto out;

    a2l = zalloc(sizeof(*a2l));
    if (a2l == NULL)
        goto out;

    a2l->abfd = abfd;
    a2l->input = strdup(path);
    if (a2l->input == NULL)
        goto out;

    if (slurp_symtab(abfd, a2l))
        goto out;

    return a2l;

out:
    if (a2l) {
        zfree((char **)&a2l->input);
        free(a2l);
    }
    bfd_close(abfd);
    return NULL;
}

static void addr2line_cleanup(struct a2l_data *a2l)
{
    if (a2l->abfd)
        bfd_close(a2l->abfd);
    zfree((char **)&a2l->input);
    zfree(&a2l->syms);
    free(a2l);
}

#define MAX_INLINE_NEST 1024

static int inline_list__append_dso_a2l(struct dso *dso,
                       struct inline_node *node,
                       struct symbol *sym)
{
    struct a2l_data *a2l = dso->a2l;
    struct symbol *inline_sym = new_inline_sym(dso, sym, a2l->funcname);
    char *srcline = NULL;

    if (a2l->filename)
        srcline = srcline_from_fileline(a2l->filename, a2l->line);

    return inline_list__append(inline_sym, srcline, node);
}

static int addr2line(const char *dso_name, u64 addr,
             char **file, unsigned int *line, struct dso *dso,
             bool unwind_inlines, struct inline_node *node,
             struct symbol *sym)
{
    int ret = 0;
    struct a2l_data *a2l = dso->a2l;

    if (!a2l) {
        dso->a2l = addr2line_init(dso_name);
        a2l = dso->a2l;
    }

    if (a2l == NULL) {
        pr_warning("addr2line_init failed for %s\n", dso_name);
        return 0;
    }

    a2l->addr = addr;
    a2l->found = false;

    bfd_map_over_sections(a2l->abfd, find_address_in_section, a2l);

    if (!a2l->found)
        return 0;

    if (unwind_inlines) {
        int cnt = 0;

        if (node && inline_list__append_dso_a2l(dso, node, sym))
            return 0;

        while (bfd_find_inliner_info(a2l->abfd, &a2l->filename,
                         &a2l->funcname, &a2l->line) &&
               cnt++ < MAX_INLINE_NEST) {

            if (a2l->filename && !strlen(a2l->filename))
                a2l->filename = NULL;

            if (node != NULL) {
                if (inline_list__append_dso_a2l(dso, node, sym))
                    return 0;
                // found at least one inline frame
                ret = 1;
            }
        }
    }

    if (file) {
        *file = a2l->filename ? strdup(a2l->filename) : NULL;
        ret = *file ? 1 : 0;
    }

    if (line)
        *line = a2l->line;

    return ret;
}

void dso__free_a2l(struct dso *dso)
{
    struct a2l_data *a2l = dso->a2l;

    if (!a2l)
        return;

    addr2line_cleanup(a2l);

    dso->a2l = NULL;
}

static struct inline_node *addr2inlines(const char *dso_name, u64 addr,
                    struct dso *dso, struct symbol *sym)
{
    struct inline_node *node;

    node = zalloc(sizeof(*node));
    if (node == NULL) {
        perror("not enough memory for the inline node");
        return NULL;
    }

    INIT_LIST_HEAD(&node->val);
    node->addr = addr;

    addr2line(dso_name, addr, NULL, NULL, dso, true, node, sym);
    return node;
}

#else /* HAVE_LIBBFD_SUPPORT */

static int filename_split(char *filename, unsigned int *line_nr)
{
    char *sep;

    sep = strchr(filename, '\n');
    if (sep)
        *sep = '\0';

    if (!strcmp(filename, "??:0"))
        return 0;

    sep = strchr(filename, ':');
    if (sep) {
        *sep++ = '\0';
        *line_nr = strtoul(sep, NULL, 0);
        return 1;
    }

    return 0;
}

static int addr2line(const char *dso_name, u64 addr,
             char **file, unsigned int *line_nr,
             struct dso *dso __maybe_unused,
             bool unwind_inlines __maybe_unused,
             struct inline_node *node __maybe_unused,
             struct symbol *sym __maybe_unused)
{
    FILE *fp;
    char cmd[PATH_MAX];
    char *filename = NULL;
    size_t len;
    int ret = 0;

    scnprintf(cmd, sizeof(cmd), "addr2line -e %s %016"PRIx64,
          dso_name, addr);

    fp = popen(cmd, "r");
    if (fp == NULL) {
        pr_warning("popen failed for %s\n", dso_name);
        return 0;
    }

    if (getline(&filename, &len, fp) < 0 || !len) {
        pr_warning("addr2line has no output for %s\n", dso_name);
        goto out;
    }

    ret = filename_split(filename, line_nr);
    if (ret != 1) {
        free(filename);
        goto out;
    }

    *file = filename;

out:
    pclose(fp);
    return ret;
}

void dso__free_a2l(struct dso *dso __maybe_unused)
{
}

static struct inline_node *addr2inlines(const char *dso_name, u64 addr,
                    struct dso *dso __maybe_unused,
                    struct symbol *sym)
{
    FILE *fp;
    char cmd[PATH_MAX];
    struct inline_node *node;
    char *filename = NULL;
    char *funcname = NULL;
    size_t filelen, funclen;
    unsigned int line_nr = 0;

    scnprintf(cmd, sizeof(cmd), "addr2line -e %s -i -f %016"PRIx64,
          dso_name, addr);

    fp = popen(cmd, "r");
    if (fp == NULL) {
        pr_err("popen failed for %s\n", dso_name);
        return NULL;
    }

    node = zalloc(sizeof(*node));
    if (node == NULL) {
        perror("not enough memory for the inline node");
        goto out;
    }

    INIT_LIST_HEAD(&node->val);
    node->addr = addr;

    /* addr2line -f generates two lines for each inlined functions */
    while (getline(&funcname, &funclen, fp) != -1) {
        char *srcline;
        struct symbol *inline_sym;

        rtrim(funcname);

        if (getline(&filename, &filelen, fp) == -1)
            goto out;

        if (filename_split(filename, &line_nr) != 1)
            goto out;

        srcline = srcline_from_fileline(filename, line_nr);
        inline_sym = new_inline_sym(dso, sym, funcname);

        if (inline_list__append(inline_sym, srcline, node) != 0) {
            free(srcline);
            if (inline_sym && inline_sym->inlined)
                symbol__delete(inline_sym);
            goto out;
        }
    }

out:
    pclose(fp);
    free(filename);
    free(funcname);

    return node;
}

#endif /* HAVE_LIBBFD_SUPPORT */

/*
 * Number of addr2line failures (without success) before disabling it for that
 * dso.
 */
#define A2L_FAIL_LIMIT 123

char *__get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
          bool show_sym, bool show_addr, bool unwind_inlines,
          u64 ip)
{
    char *file = NULL;
    unsigned line = 0;
    char *srcline;
    const char *dso_name;

    if (!dso->has_srcline)
        goto out;

    dso_name = dso__name(dso);
    if (dso_name == NULL)
        goto out;

    if (!addr2line(dso_name, addr, &file, &line, dso,
               unwind_inlines, NULL, sym))
        goto out;

    srcline = srcline_from_fileline(file, line);
    free(file);

    if (!srcline)
        goto out;

    dso->a2l_fails = 0;

    return srcline;

out:
    if (dso->a2l_fails && ++dso->a2l_fails > A2L_FAIL_LIMIT) {
        dso->has_srcline = 0;
        dso__free_a2l(dso);
    }

    if (!show_addr)
        return (show_sym && sym) ?
                strndup(sym->name, sym->namelen) : NULL;

    if (sym) {
        if (asprintf(&srcline, "%s+%" PRIu64, show_sym ? sym->name : "",
                    ip - sym->start) < 0)
            return SRCLINE_UNKNOWN;
    } else if (asprintf(&srcline, "%s[%" PRIx64 "]", dso->short_name, addr) < 0)
        return SRCLINE_UNKNOWN;
    return srcline;
}

void free_srcline(char *srcline)
{
    if (srcline && strcmp(srcline, SRCLINE_UNKNOWN) != 0)
        free(srcline);
}

char *get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
          bool show_sym, bool show_addr, u64 ip)
{
    return __get_srcline(dso, addr, sym, show_sym, show_addr, false, ip);
}

struct srcline_node {
    u64         addr;
    char            *srcline;
    struct rb_node      rb_node;
};

void srcline__tree_insert(struct rb_root *tree, u64 addr, char *srcline)
{
    struct rb_node **p = &tree->rb_node;
    struct rb_node *parent = NULL;
    struct srcline_node *i, *node;

    node = zalloc(sizeof(struct srcline_node));
    if (!node) {
        perror("not enough memory for the srcline node");
        return;
    }

    node->addr = addr;
    node->srcline = srcline;

    while (*p != NULL) {
        parent = *p;
        i = rb_entry(parent, struct srcline_node, rb_node);
        if (addr < i->addr)
            p = &(*p)->rb_left;
        else
            p = &(*p)->rb_right;
    }
    rb_link_node(&node->rb_node, parent, p);
    rb_insert_color(&node->rb_node, tree);
}

char *srcline__tree_find(struct rb_root *tree, u64 addr)
{
    struct rb_node *n = tree->rb_node;

    while (n) {
        struct srcline_node *i = rb_entry(n, struct srcline_node,
                          rb_node);

        if (addr < i->addr)
            n = n->rb_left;
        else if (addr > i->addr)
            n = n->rb_right;
        else
            return i->srcline;
    }

    return NULL;
}

void srcline__tree_delete(struct rb_root *tree)
{
    struct srcline_node *pos;
    struct rb_node *next = rb_first(tree);

    while (next) {
        pos = rb_entry(next, struct srcline_node, rb_node);
        next = rb_next(&pos->rb_node);
        rb_erase(&pos->rb_node, tree);
        free_srcline(pos->srcline);
        zfree(&pos);
    }
}

struct inline_node *dso__parse_addr_inlines(struct dso *dso, u64 addr,
                        struct symbol *sym)
{
    const char *dso_name;

    dso_name = dso__name(dso);
    if (dso_name == NULL)
        return NULL;

    return addr2inlines(dso_name, addr, dso, sym);
}

void inline_node__delete(struct inline_node *node)
{
    struct inline_list *ilist, *tmp;

    list_for_each_entry_safe(ilist, tmp, &node->val, list) {
        list_del_init(&ilist->list);
        free_srcline(ilist->srcline);
        /* only the inlined symbols are owned by the list */
        if (ilist->symbol && ilist->symbol->inlined)
            symbol__delete(ilist->symbol);
        free(ilist);
    }

    free(node);
}

void inlines__tree_insert(struct rb_root *tree, struct inline_node *inlines)
{
    struct rb_node **p = &tree->rb_node;
    struct rb_node *parent = NULL;
    const u64 addr = inlines->addr;
    struct inline_node *i;

    while (*p != NULL) {
        parent = *p;
        i = rb_entry(parent, struct inline_node, rb_node);
        if (addr < i->addr)
            p = &(*p)->rb_left;
        else
            p = &(*p)->rb_right;
    }
    rb_link_node(&inlines->rb_node, parent, p);
    rb_insert_color(&inlines->rb_node, tree);
}

struct inline_node *inlines__tree_find(struct rb_root *tree, u64 addr)
{
    struct rb_node *n = tree->rb_node;

    while (n) {
        struct inline_node *i = rb_entry(n, struct inline_node,
                         rb_node);

        if (addr < i->addr)
            n = n->rb_left;
        else if (addr > i->addr)
            n = n->rb_right;
        else
            return i;
    }

    return NULL;
}

void inlines__tree_delete(struct rb_root *tree)
{
    struct inline_node *pos;
    struct rb_node *next = rb_first(tree);

    while (next) {
        pos = rb_entry(next, struct inline_node, rb_node);
        next = rb_next(&pos->rb_node);
        rb_erase(&pos->rb_node, tree);
        inline_node__delete(pos);
    }
}