build-id.c

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// SPDX-License-Identifier: GPL-2.0
/*
 * build-id.c
 *
 * build-id support
 *
 * Copyright (C) 2009, 2010 Red Hat Inc.
 * Copyright (C) 2009, 2010 Arnaldo Carvalho de Melo <acme@redhat.com>
 */
#include "util.h"
#include <dirent.h>
#include <errno.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
#include "build-id.h"
#include "event.h"
#include "symbol.h"
#include "thread.h"
#include <linux/kernel.h>
#include "debug.h"
#include "session.h"
#include "tool.h"
#include "header.h"
#include "vdso.h"
#include "path.h"
#include "probe-file.h"
#include "strlist.h"

#include "sane_ctype.h"

static bool no_buildid_cache;

int build_id__mark_dso_hit(struct perf_tool *tool __maybe_unused,
               union perf_event *event,
               struct perf_sample *sample,
               struct perf_evsel *evsel __maybe_unused,
               struct machine *machine)
{
    struct addr_location al;
    struct thread *thread = machine__findnew_thread(machine, sample->pid,
                            sample->tid);

    if (thread == NULL) {
        pr_err("problem processing %d event, skipping it.\n",
            event->header.type);
        return -1;
    }

    if (thread__find_map(thread, sample->cpumode, sample->ip, &al))
        al.map->dso->hit = 1;

    thread__put(thread);
    return 0;
}

static int perf_event__exit_del_thread(struct perf_tool *tool __maybe_unused,
                       union perf_event *event,
                       struct perf_sample *sample
                       __maybe_unused,
                       struct machine *machine)
{
    struct thread *thread = machine__findnew_thread(machine,
                            event->fork.pid,
                            event->fork.tid);

    dump_printf("(%d:%d):(%d:%d)\n", event->fork.pid, event->fork.tid,
            event->fork.ppid, event->fork.ptid);

    if (thread) {
        machine__remove_thread(machine, thread);
        thread__put(thread);
    }

    return 0;
}

struct perf_tool build_id__mark_dso_hit_ops = {
    .sample = build_id__mark_dso_hit,
    .mmap   = perf_event__process_mmap,
    .mmap2  = perf_event__process_mmap2,
    .fork   = perf_event__process_fork,
    .exit   = perf_event__exit_del_thread,
    .attr        = perf_event__process_attr,
    .build_id    = perf_event__process_build_id,
    .ordered_events  = true,
};

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

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

    return (bid - bf) + 1;
}

int sysfs__sprintf_build_id(const char *root_dir, char *sbuild_id)
{
    char notes[PATH_MAX];
    u8 build_id[BUILD_ID_SIZE];
    int ret;

    if (!root_dir)
        root_dir = "";

    scnprintf(notes, sizeof(notes), "%s/sys/kernel/notes", root_dir);

    ret = sysfs__read_build_id(notes, build_id, sizeof(build_id));
    if (ret < 0)
        return ret;

    return build_id__sprintf(build_id, sizeof(build_id), sbuild_id);
}

int filename__sprintf_build_id(const char *pathname, char *sbuild_id)
{
    u8 build_id[BUILD_ID_SIZE];
    int ret;

    ret = filename__read_build_id(pathname, build_id, sizeof(build_id));
    if (ret < 0)
        return ret;
    else if (ret != sizeof(build_id))
        return -EINVAL;

    return build_id__sprintf(build_id, sizeof(build_id), sbuild_id);
}

/* asnprintf consolidates asprintf and snprintf */
static int asnprintf(char **strp, size_t size, const char *fmt, ...)
{
    va_list ap;
    int ret;

    if (!strp)
        return -EINVAL;

    va_start(ap, fmt);
    if (*strp)
        ret = vsnprintf(*strp, size, fmt, ap);
    else
        ret = vasprintf(strp, fmt, ap);
    va_end(ap);

    return ret;
}

char *build_id_cache__kallsyms_path(const char *sbuild_id, char *bf,
                    size_t size)
{
    bool retry_old = true;

    snprintf(bf, size, "%s/%s/%s/kallsyms",
         buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
retry:
    if (!access(bf, F_OK))
        return bf;
    if (retry_old) {
        /* Try old style kallsyms cache */
        snprintf(bf, size, "%s/%s/%s",
             buildid_dir, DSO__NAME_KALLSYMS, sbuild_id);
        retry_old = false;
        goto retry;
    }

    return NULL;
}

char *build_id_cache__linkname(const char *sbuild_id, char *bf, size_t size)
{
    char *tmp = bf;
    int ret = asnprintf(&bf, size, "%s/.build-id/%.2s/%s", buildid_dir,
                sbuild_id, sbuild_id + 2);
    if (ret < 0 || (tmp && size < (unsigned int)ret))
        return NULL;
    return bf;
}

char *build_id_cache__origname(const char *sbuild_id)
{
    char *linkname;
    char buf[PATH_MAX];
    char *ret = NULL, *p;
    size_t offs = 5;    /* == strlen("../..") */
    ssize_t len;

    linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
    if (!linkname)
        return NULL;

    len = readlink(linkname, buf, sizeof(buf) - 1);
    if (len <= 0)
        goto out;
    buf[len] = '\0';

    /* The link should be "../..<origpath>/<sbuild_id>" */
    p = strrchr(buf, '/');  /* Cut off the "/<sbuild_id>" */
    if (p && (p > buf + offs)) {
        *p = '\0';
        if (buf[offs + 1] == '[')
            offs++; /*
                 * This is a DSO name, like [kernel.kallsyms].
                 * Skip the first '/', since this is not the
                 * cache of a regular file.
                 */
        ret = strdup(buf + offs);   /* Skip "../..[/]" */
    }
out:
    free(linkname);
    return ret;
}

/* Check if the given build_id cache is valid on current running system */
static bool build_id_cache__valid_id(char *sbuild_id)
{
    char real_sbuild_id[SBUILD_ID_SIZE] = "";
    char *pathname;
    int ret = 0;
    bool result = false;

    pathname = build_id_cache__origname(sbuild_id);
    if (!pathname)
        return false;

    if (!strcmp(pathname, DSO__NAME_KALLSYMS))
        ret = sysfs__sprintf_build_id("/", real_sbuild_id);
    else if (pathname[0] == '/')
        ret = filename__sprintf_build_id(pathname, real_sbuild_id);
    else
        ret = -EINVAL;  /* Should we support other special DSO cache? */
    if (ret >= 0)
        result = (strcmp(sbuild_id, real_sbuild_id) == 0);
    free(pathname);

    return result;
}

static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso,
                        bool is_debug)
{
    return is_kallsyms ? "kallsyms" : (is_vdso ? "vdso" : (is_debug ?
        "debug" : "elf"));
}

char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
                 bool is_debug)
{
    bool is_kallsyms = dso__is_kallsyms((struct dso *)dso);
    bool is_vdso = dso__is_vdso((struct dso *)dso);
    char sbuild_id[SBUILD_ID_SIZE];
    char *linkname;
    bool alloc = (bf == NULL);
    int ret;

    if (!dso->has_build_id)
        return NULL;

    build_id__sprintf(dso->build_id, sizeof(dso->build_id), sbuild_id);
    linkname = build_id_cache__linkname(sbuild_id, NULL, 0);
    if (!linkname)
        return NULL;

    /* Check if old style build_id cache */
    if (is_regular_file(linkname))
        ret = asnprintf(&bf, size, "%s", linkname);
    else
        ret = asnprintf(&bf, size, "%s/%s", linkname,
             build_id_cache__basename(is_kallsyms, is_vdso,
                          is_debug));
    if (ret < 0 || (!alloc && size < (unsigned int)ret))
        bf = NULL;
    free(linkname);

    return bf;
}

#define dsos__for_each_with_build_id(pos, head) \
    list_for_each_entry(pos, head, node)    \
        if (!pos->has_build_id)     \
            continue;       \
        else

static int write_buildid(const char *name, size_t name_len, u8 *build_id,
             pid_t pid, u16 misc, struct feat_fd *fd)
{
    int err;
    struct build_id_event b;
    size_t len;

    len = name_len + 1;
    len = PERF_ALIGN(len, NAME_ALIGN);

    memset(&b, 0, sizeof(b));
    memcpy(&b.build_id, build_id, BUILD_ID_SIZE);
    b.pid = pid;
    b.header.misc = misc;
    b.header.size = sizeof(b) + len;

    err = do_write(fd, &b, sizeof(b));
    if (err < 0)
        return err;

    return write_padded(fd, name, name_len + 1, len);
}

static int machine__write_buildid_table(struct machine *machine,
                    struct feat_fd *fd)
{
    int err = 0;
    struct dso *pos;
    u16 kmisc = PERF_RECORD_MISC_KERNEL,
        umisc = PERF_RECORD_MISC_USER;

    if (!machine__is_host(machine)) {
        kmisc = PERF_RECORD_MISC_GUEST_KERNEL;
        umisc = PERF_RECORD_MISC_GUEST_USER;
    }

    dsos__for_each_with_build_id(pos, &machine->dsos.head) {
        const char *name;
        size_t name_len;
        bool in_kernel = false;

        if (!pos->hit && !dso__is_vdso(pos))
            continue;

        if (dso__is_vdso(pos)) {
            name = pos->short_name;
            name_len = pos->short_name_len;
        } else if (dso__is_kcore(pos)) {
            name = machine->mmap_name;
            name_len = strlen(name);
        } else {
            name = pos->long_name;
            name_len = pos->long_name_len;
        }

        in_kernel = pos->kernel ||
                is_kernel_module(name,
                    PERF_RECORD_MISC_CPUMODE_UNKNOWN);
        err = write_buildid(name, name_len, pos->build_id, machine->pid,
                    in_kernel ? kmisc : umisc, fd);
        if (err)
            break;
    }

    return err;
}

int perf_session__write_buildid_table(struct perf_session *session,
                      struct feat_fd *fd)
{
    struct rb_node *nd;
    int err = machine__write_buildid_table(&session->machines.host, fd);

    if (err)
        return err;

    for (nd = rb_first(&session->machines.guests); nd; nd = rb_next(nd)) {
        struct machine *pos = rb_entry(nd, struct machine, rb_node);
        err = machine__write_buildid_table(pos, fd);
        if (err)
            break;
    }
    return err;
}

static int __dsos__hit_all(struct list_head *head)
{
    struct dso *pos;

    list_for_each_entry(pos, head, node)
        pos->hit = true;

    return 0;
}

static int machine__hit_all_dsos(struct machine *machine)
{
    return __dsos__hit_all(&machine->dsos.head);
}

int dsos__hit_all(struct perf_session *session)
{
    struct rb_node *nd;
    int err;

    err = machine__hit_all_dsos(&session->machines.host);
    if (err)
        return err;

    for (nd = rb_first(&session->machines.guests); nd; nd = rb_next(nd)) {
        struct machine *pos = rb_entry(nd, struct machine, rb_node);

        err = machine__hit_all_dsos(pos);
        if (err)
            return err;
    }

    return 0;
}

void disable_buildid_cache(void)
{
    no_buildid_cache = true;
}

static bool lsdir_bid_head_filter(const char *name __maybe_unused,
                  struct dirent *d)
{
    return (strlen(d->d_name) == 2) &&
        isxdigit(d->d_name[0]) && isxdigit(d->d_name[1]);
}

static bool lsdir_bid_tail_filter(const char *name __maybe_unused,
                  struct dirent *d)
{
    int i = 0;
    while (isxdigit(d->d_name[i]) && i < SBUILD_ID_SIZE - 3)
        i++;
    return (i == SBUILD_ID_SIZE - 3) && (d->d_name[i] == '\0');
}

struct strlist *build_id_cache__list_all(bool validonly)
{
    struct strlist *toplist, *linklist = NULL, *bidlist;
    struct str_node *nd, *nd2;
    char *topdir, *linkdir = NULL;
    char sbuild_id[SBUILD_ID_SIZE];

    /* for filename__ functions */
    if (validonly)
        symbol__init(NULL);

    /* Open the top-level directory */
    if (asprintf(&topdir, "%s/.build-id/", buildid_dir) < 0)
        return NULL;

    bidlist = strlist__new(NULL, NULL);
    if (!bidlist)
        goto out;

    toplist = lsdir(topdir, lsdir_bid_head_filter);
    if (!toplist) {
        pr_debug("Error in lsdir(%s): %d\n", topdir, errno);
        /* If there is no buildid cache, return an empty list */
        if (errno == ENOENT)
            goto out;
        goto err_out;
    }

    strlist__for_each_entry(nd, toplist) {
        if (asprintf(&linkdir, "%s/%s", topdir, nd->s) < 0)
            goto err_out;
        /* Open the lower-level directory */
        linklist = lsdir(linkdir, lsdir_bid_tail_filter);
        if (!linklist) {
            pr_debug("Error in lsdir(%s): %d\n", linkdir, errno);
            goto err_out;
        }
        strlist__for_each_entry(nd2, linklist) {
            if (snprintf(sbuild_id, SBUILD_ID_SIZE, "%s%s",
                     nd->s, nd2->s) != SBUILD_ID_SIZE - 1)
                goto err_out;
            if (validonly && !build_id_cache__valid_id(sbuild_id))
                continue;
            if (strlist__add(bidlist, sbuild_id) < 0)
                goto err_out;
        }
        strlist__delete(linklist);
        zfree(&linkdir);
    }

out_free:
    strlist__delete(toplist);
out:
    free(topdir);

    return bidlist;

err_out:
    strlist__delete(linklist);
    zfree(&linkdir);
    strlist__delete(bidlist);
    bidlist = NULL;
    goto out_free;
}

static bool str_is_build_id(const char *maybe_sbuild_id, size_t len)
{
    size_t i;

    for (i = 0; i < len; i++) {
        if (!isxdigit(maybe_sbuild_id[i]))
            return false;
    }
    return true;
}

/* Return the valid complete build-id */
char *build_id_cache__complement(const char *incomplete_sbuild_id)
{
    struct strlist *bidlist;
    struct str_node *nd, *cand = NULL;
    char *sbuild_id = NULL;
    size_t len = strlen(incomplete_sbuild_id);

    if (len >= SBUILD_ID_SIZE ||
        !str_is_build_id(incomplete_sbuild_id, len))
        return NULL;

    bidlist = build_id_cache__list_all(true);
    if (!bidlist)
        return NULL;

    strlist__for_each_entry(nd, bidlist) {
        if (strncmp(nd->s, incomplete_sbuild_id, len) != 0)
            continue;
        if (cand) { /* Error: There are more than 2 candidates. */
            cand = NULL;
            break;
        }
        cand = nd;
    }
    if (cand)
        sbuild_id = strdup(cand->s);
    strlist__delete(bidlist);

    return sbuild_id;
}

char *build_id_cache__cachedir(const char *sbuild_id, const char *name,
                   struct nsinfo *nsi, bool is_kallsyms,
                   bool is_vdso)
{
    char *realname = (char *)name, *filename;
    bool slash = is_kallsyms || is_vdso;

    if (!slash) {
        realname = nsinfo__realpath(name, nsi);
        if (!realname)
            return NULL;
    }

    if (asprintf(&filename, "%s%s%s%s%s", buildid_dir, slash ? "/" : "",
             is_vdso ? DSO__NAME_VDSO : realname,
             sbuild_id ? "/" : "", sbuild_id ?: "") < 0)
        filename = NULL;

    if (!slash)
        free(realname);

    return filename;
}

int build_id_cache__list_build_ids(const char *pathname, struct nsinfo *nsi,
                   struct strlist **result)
{
    char *dir_name;
    int ret = 0;

    dir_name = build_id_cache__cachedir(NULL, pathname, nsi, false, false);
    if (!dir_name)
        return -ENOMEM;

    *result = lsdir(dir_name, lsdir_no_dot_filter);
    if (!*result)
        ret = -errno;
    free(dir_name);

    return ret;
}

#if defined(HAVE_LIBELF_SUPPORT) && defined(HAVE_GELF_GETNOTE_SUPPORT)
static int build_id_cache__add_sdt_cache(const char *sbuild_id,
                      const char *realname,
                      struct nsinfo *nsi)
{
    struct probe_cache *cache;
    int ret;
    struct nscookie nsc;

    cache = probe_cache__new(sbuild_id, nsi);
    if (!cache)
        return -1;

    nsinfo__mountns_enter(nsi, &nsc);
    ret = probe_cache__scan_sdt(cache, realname);
    nsinfo__mountns_exit(&nsc);
    if (ret >= 0) {
        pr_debug4("Found %d SDTs in %s\n", ret, realname);
        if (probe_cache__commit(cache) < 0)
            ret = -1;
    }
    probe_cache__delete(cache);
    return ret;
}
#else
#define build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) (0)
#endif

static char *build_id_cache__find_debug(const char *sbuild_id,
                    struct nsinfo *nsi)
{
    char *realname = NULL;
    char *debugfile;
    struct nscookie nsc;
    size_t len = 0;

    debugfile = calloc(1, PATH_MAX);
    if (!debugfile)
        goto out;

    len = __symbol__join_symfs(debugfile, PATH_MAX,
                   "/usr/lib/debug/.build-id/");
    snprintf(debugfile + len, PATH_MAX - len, "%.2s/%s.debug", sbuild_id,
         sbuild_id + 2);

    nsinfo__mountns_enter(nsi, &nsc);
    realname = realpath(debugfile, NULL);
    if (realname && access(realname, R_OK))
        zfree(&realname);
    nsinfo__mountns_exit(&nsc);
out:
    free(debugfile);
    return realname;
}

int build_id_cache__add_s(const char *sbuild_id, const char *name,
              struct nsinfo *nsi, bool is_kallsyms, bool is_vdso)
{
    const size_t size = PATH_MAX;
    char *realname = NULL, *filename = NULL, *dir_name = NULL,
         *linkname = zalloc(size), *tmp;
    char *debugfile = NULL;
    int err = -1;

    if (!is_kallsyms) {
        if (!is_vdso)
            realname = nsinfo__realpath(name, nsi);
        else
            realname = realpath(name, NULL);
        if (!realname)
            goto out_free;
    }

    dir_name = build_id_cache__cachedir(sbuild_id, name, nsi, is_kallsyms,
                        is_vdso);
    if (!dir_name)
        goto out_free;

    /* Remove old style build-id cache */
    if (is_regular_file(dir_name))
        if (unlink(dir_name))
            goto out_free;

    if (mkdir_p(dir_name, 0755))
        goto out_free;

    /* Save the allocated buildid dirname */
    if (asprintf(&filename, "%s/%s", dir_name,
             build_id_cache__basename(is_kallsyms, is_vdso,
             false)) < 0) {
        filename = NULL;
        goto out_free;
    }

    if (access(filename, F_OK)) {
        if (is_kallsyms) {
            if (copyfile("/proc/kallsyms", filename))
                goto out_free;
        } else if (nsi && nsi->need_setns) {
            if (copyfile_ns(name, filename, nsi))
                goto out_free;
        } else if (link(realname, filename) && errno != EEXIST &&
                copyfile(name, filename))
            goto out_free;
    }

    /* Some binaries are stripped, but have .debug files with their symbol
     * table.  Check to see if we can locate one of those, since the elf
     * file itself may not be very useful to users of our tools without a
     * symtab.
     */
    if (!is_kallsyms && !is_vdso &&
        strncmp(".ko", name + strlen(name) - 3, 3)) {
        debugfile = build_id_cache__find_debug(sbuild_id, nsi);
        if (debugfile) {
            zfree(&filename);
            if (asprintf(&filename, "%s/%s", dir_name,
                build_id_cache__basename(false, false, true)) < 0) {
                filename = NULL;
                goto out_free;
            }
            if (access(filename, F_OK)) {
                if (nsi && nsi->need_setns) {
                    if (copyfile_ns(debugfile, filename,
                            nsi))
                        goto out_free;
                } else if (link(debugfile, filename) &&
                        errno != EEXIST &&
                        copyfile(debugfile, filename))
                    goto out_free;
            }
        }
    }

    if (!build_id_cache__linkname(sbuild_id, linkname, size))
        goto out_free;
    tmp = strrchr(linkname, '/');
    *tmp = '\0';

    if (access(linkname, X_OK) && mkdir_p(linkname, 0755))
        goto out_free;

    *tmp = '/';
    tmp = dir_name + strlen(buildid_dir) - 5;
    memcpy(tmp, "../..", 5);

    if (symlink(tmp, linkname) == 0)
        err = 0;

    /* Update SDT cache : error is just warned */
    if (realname &&
        build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) < 0)
        pr_debug4("Failed to update/scan SDT cache for %s\n", realname);

out_free:
    if (!is_kallsyms)
        free(realname);
    free(filename);
    free(debugfile);
    free(dir_name);
    free(linkname);
    return err;
}

static int build_id_cache__add_b(const u8 *build_id, size_t build_id_size,
                 const char *name, struct nsinfo *nsi,
                 bool is_kallsyms, bool is_vdso)
{
    char sbuild_id[SBUILD_ID_SIZE];

    build_id__sprintf(build_id, build_id_size, sbuild_id);

    return build_id_cache__add_s(sbuild_id, name, nsi, is_kallsyms,
                     is_vdso);
}

bool build_id_cache__cached(const char *sbuild_id)
{
    bool ret = false;
    char *filename = build_id_cache__linkname(sbuild_id, NULL, 0);

    if (filename && !access(filename, F_OK))
        ret = true;
    free(filename);

    return ret;
}

int build_id_cache__remove_s(const char *sbuild_id)
{
    const size_t size = PATH_MAX;
    char *filename = zalloc(size),
         *linkname = zalloc(size), *tmp;
    int err = -1;

    if (filename == NULL || linkname == NULL)
        goto out_free;

    if (!build_id_cache__linkname(sbuild_id, linkname, size))
        goto out_free;

    if (access(linkname, F_OK))
        goto out_free;

    if (readlink(linkname, filename, size - 1) < 0)
        goto out_free;

    if (unlink(linkname))
        goto out_free;

    /*
     * Since the link is relative, we must make it absolute:
     */
    tmp = strrchr(linkname, '/') + 1;
    snprintf(tmp, size - (tmp - linkname), "%s", filename);

    if (rm_rf(linkname))
        goto out_free;

    err = 0;
out_free:
    free(filename);
    free(linkname);
    return err;
}

static int dso__cache_build_id(struct dso *dso, struct machine *machine)
{
    bool is_kallsyms = dso__is_kallsyms(dso);
    bool is_vdso = dso__is_vdso(dso);
    const char *name = dso->long_name;

    if (dso__is_kcore(dso)) {
        is_kallsyms = true;
        name = machine->mmap_name;
    }
    return build_id_cache__add_b(dso->build_id, sizeof(dso->build_id), name,
                     dso->nsinfo, is_kallsyms, is_vdso);
}

static int __dsos__cache_build_ids(struct list_head *head,
                   struct machine *machine)
{
    struct dso *pos;
    int err = 0;

    dsos__for_each_with_build_id(pos, head)
        if (dso__cache_build_id(pos, machine))
            err = -1;

    return err;
}

static int machine__cache_build_ids(struct machine *machine)
{
    return __dsos__cache_build_ids(&machine->dsos.head, machine);
}

int perf_session__cache_build_ids(struct perf_session *session)
{
    struct rb_node *nd;
    int ret;

    if (no_buildid_cache)
        return 0;

    if (mkdir(buildid_dir, 0755) != 0 && errno != EEXIST)
        return -1;

    ret = machine__cache_build_ids(&session->machines.host);

    for (nd = rb_first(&session->machines.guests); nd; nd = rb_next(nd)) {
        struct machine *pos = rb_entry(nd, struct machine, rb_node);
        ret |= machine__cache_build_ids(pos);
    }
    return ret ? -1 : 0;
}

static bool machine__read_build_ids(struct machine *machine, bool with_hits)
{
    return __dsos__read_build_ids(&machine->dsos.head, with_hits);
}

bool perf_session__read_build_ids(struct perf_session *session, bool with_hits)
{
    struct rb_node *nd;
    bool ret = machine__read_build_ids(&session->machines.host, with_hits);

    for (nd = rb_first(&session->machines.guests); nd; nd = rb_next(nd)) {
        struct machine *pos = rb_entry(nd, struct machine, rb_node);
        ret |= machine__read_build_ids(pos, with_hits);
    }

    return ret;
}