header.c

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// SPDX-License-Identifier: GPL-2.0
#include <errno.h>
#include <inttypes.h>
#include "util.h"
#include "string2.h"
#include <sys/param.h>
#include <sys/types.h>
#include <byteswap.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <linux/compiler.h>
#include <linux/list.h>
#include <linux/kernel.h>
#include <linux/bitops.h>
#include <linux/stringify.h>
#include <sys/stat.h>
#include <sys/utsname.h>
#include <linux/time64.h>
#include <dirent.h>

#include "evlist.h"
#include "evsel.h"
#include "header.h"
#include "memswap.h"
#include "../perf.h"
#include "trace-event.h"
#include "session.h"
#include "symbol.h"
#include "debug.h"
#include "cpumap.h"
#include "pmu.h"
#include "vdso.h"
#include "strbuf.h"
#include "build-id.h"
#include "data.h"
#include <api/fs/fs.h>
#include "asm/bug.h"
#include "tool.h"
#include "time-utils.h"
#include "units.h"

#include "sane_ctype.h"

/*
 * magic2 = "PERFILE2"
 * must be a numerical value to let the endianness
 * determine the memory layout. That way we are able
 * to detect endianness when reading the perf.data file
 * back.
 *
 * we check for legacy (PERFFILE) format.
 */
static const char *__perf_magic1 = "PERFFILE";
static const u64 __perf_magic2    = 0x32454c4946524550ULL;
static const u64 __perf_magic2_sw = 0x50455246494c4532ULL;

#define PERF_MAGIC  __perf_magic2

const char perf_version_string[] = PERF_VERSION;

struct perf_file_attr {
    struct perf_event_attr  attr;
    struct perf_file_section    ids;
};

struct feat_fd {
    struct perf_header  *ph;
    int         fd;
    void            *buf;   /* Either buf != NULL or fd >= 0 */
    ssize_t         offset;
    size_t          size;
    struct perf_evsel   *events;
};

void perf_header__set_feat(struct perf_header *header, int feat)
{
    set_bit(feat, header->adds_features);
}

void perf_header__clear_feat(struct perf_header *header, int feat)
{
    clear_bit(feat, header->adds_features);
}

bool perf_header__has_feat(const struct perf_header *header, int feat)
{
    return test_bit(feat, header->adds_features);
}

static int __do_write_fd(struct feat_fd *ff, const void *buf, size_t size)
{
    ssize_t ret = writen(ff->fd, buf, size);

    if (ret != (ssize_t)size)
        return ret < 0 ? (int)ret : -1;
    return 0;
}

static int __do_write_buf(struct feat_fd *ff,  const void *buf, size_t size)
{
    /* struct perf_event_header::size is u16 */
    const size_t max_size = 0xffff - sizeof(struct perf_event_header);
    size_t new_size = ff->size;
    void *addr;

    if (size + ff->offset > max_size)
        return -E2BIG;

    while (size > (new_size - ff->offset))
        new_size <<= 1;
    new_size = min(max_size, new_size);

    if (ff->size < new_size) {
        addr = realloc(ff->buf, new_size);
        if (!addr)
            return -ENOMEM;
        ff->buf = addr;
        ff->size = new_size;
    }

    memcpy(ff->buf + ff->offset, buf, size);
    ff->offset += size;

    return 0;
}

/* Return: 0 if succeded, -ERR if failed. */
int do_write(struct feat_fd *ff, const void *buf, size_t size)
{
    if (!ff->buf)
        return __do_write_fd(ff, buf, size);
    return __do_write_buf(ff, buf, size);
}

/* Return: 0 if succeded, -ERR if failed. */
static int do_write_bitmap(struct feat_fd *ff, unsigned long *set, u64 size)
{
    u64 *p = (u64 *) set;
    int i, ret;

    ret = do_write(ff, &size, sizeof(size));
    if (ret < 0)
        return ret;

    for (i = 0; (u64) i < BITS_TO_U64(size); i++) {
        ret = do_write(ff, p + i, sizeof(*p));
        if (ret < 0)
            return ret;
    }

    return 0;
}

/* Return: 0 if succeded, -ERR if failed. */
int write_padded(struct feat_fd *ff, const void *bf,
         size_t count, size_t count_aligned)
{
    static const char zero_buf[NAME_ALIGN];
    int err = do_write(ff, bf, count);

    if (!err)
        err = do_write(ff, zero_buf, count_aligned - count);

    return err;
}

#define string_size(str)                        \
    (PERF_ALIGN((strlen(str) + 1), NAME_ALIGN) + sizeof(u32))

/* Return: 0 if succeded, -ERR if failed. */
static int do_write_string(struct feat_fd *ff, const char *str)
{
    u32 len, olen;
    int ret;

    olen = strlen(str) + 1;
    len = PERF_ALIGN(olen, NAME_ALIGN);

    /* write len, incl. \0 */
    ret = do_write(ff, &len, sizeof(len));
    if (ret < 0)
        return ret;

    return write_padded(ff, str, olen, len);
}

static int __do_read_fd(struct feat_fd *ff, void *addr, ssize_t size)
{
    ssize_t ret = readn(ff->fd, addr, size);

    if (ret != size)
        return ret < 0 ? (int)ret : -1;
    return 0;
}

static int __do_read_buf(struct feat_fd *ff, void *addr, ssize_t size)
{
    if (size > (ssize_t)ff->size - ff->offset)
        return -1;

    memcpy(addr, ff->buf + ff->offset, size);
    ff->offset += size;

    return 0;

}

static int __do_read(struct feat_fd *ff, void *addr, ssize_t size)
{
    if (!ff->buf)
        return __do_read_fd(ff, addr, size);
    return __do_read_buf(ff, addr, size);
}

static int do_read_u32(struct feat_fd *ff, u32 *addr)
{
    int ret;

    ret = __do_read(ff, addr, sizeof(*addr));
    if (ret)
        return ret;

    if (ff->ph->needs_swap)
        *addr = bswap_32(*addr);
    return 0;
}

static int do_read_u64(struct feat_fd *ff, u64 *addr)
{
    int ret;

    ret = __do_read(ff, addr, sizeof(*addr));
    if (ret)
        return ret;

    if (ff->ph->needs_swap)
        *addr = bswap_64(*addr);
    return 0;
}

static char *do_read_string(struct feat_fd *ff)
{
    u32 len;
    char *buf;

    if (do_read_u32(ff, &len))
        return NULL;

    buf = malloc(len);
    if (!buf)
        return NULL;

    if (!__do_read(ff, buf, len)) {
        /*
         * strings are padded by zeroes
         * thus the actual strlen of buf
         * may be less than len
         */
        return buf;
    }

    free(buf);
    return NULL;
}

/* Return: 0 if succeded, -ERR if failed. */
static int do_read_bitmap(struct feat_fd *ff, unsigned long **pset, u64 *psize)
{
    unsigned long *set;
    u64 size, *p;
    int i, ret;

    ret = do_read_u64(ff, &size);
    if (ret)
        return ret;

    set = bitmap_alloc(size);
    if (!set)
        return -ENOMEM;

    bitmap_zero(set, size);

    p = (u64 *) set;

    for (i = 0; (u64) i < BITS_TO_U64(size); i++) {
        ret = do_read_u64(ff, p + i);
        if (ret < 0) {
            free(set);
            return ret;
        }
    }

    *pset  = set;
    *psize = size;
    return 0;
}

static int write_tracing_data(struct feat_fd *ff,
                  struct perf_evlist *evlist)
{
    if (WARN(ff->buf, "Error: calling %s in pipe-mode.\n", __func__))
        return -1;

    return read_tracing_data(ff->fd, &evlist->entries);
}

static int write_build_id(struct feat_fd *ff,
              struct perf_evlist *evlist __maybe_unused)
{
    struct perf_session *session;
    int err;

    session = container_of(ff->ph, struct perf_session, header);

    if (!perf_session__read_build_ids(session, true))
        return -1;

    if (WARN(ff->buf, "Error: calling %s in pipe-mode.\n", __func__))
        return -1;

    err = perf_session__write_buildid_table(session, ff);
    if (err < 0) {
        pr_debug("failed to write buildid table\n");
        return err;
    }
    perf_session__cache_build_ids(session);

    return 0;
}

static int write_hostname(struct feat_fd *ff,
              struct perf_evlist *evlist __maybe_unused)
{
    struct utsname uts;
    int ret;

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

    return do_write_string(ff, uts.nodename);
}

static int write_osrelease(struct feat_fd *ff,
               struct perf_evlist *evlist __maybe_unused)
{
    struct utsname uts;
    int ret;

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

    return do_write_string(ff, uts.release);
}

static int write_arch(struct feat_fd *ff,
              struct perf_evlist *evlist __maybe_unused)
{
    struct utsname uts;
    int ret;

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

    return do_write_string(ff, uts.machine);
}

static int write_version(struct feat_fd *ff,
             struct perf_evlist *evlist __maybe_unused)
{
    return do_write_string(ff, perf_version_string);
}

static int __write_cpudesc(struct feat_fd *ff, const char *cpuinfo_proc)
{
    FILE *file;
    char *buf = NULL;
    char *s, *p;
    const char *search = cpuinfo_proc;
    size_t len = 0;
    int ret = -1;

    if (!search)
        return -1;

    file = fopen("/proc/cpuinfo", "r");
    if (!file)
        return -1;

    while (getline(&buf, &len, file) > 0) {
        ret = strncmp(buf, search, strlen(search));
        if (!ret)
            break;
    }

    if (ret) {
        ret = -1;
        goto done;
    }

    s = buf;

    p = strchr(buf, ':');
    if (p && *(p+1) == ' ' && *(p+2))
        s = p + 2;
    p = strchr(s, '\n');
    if (p)
        *p = '\0';

    /* squash extra space characters (branding string) */
    p = s;
    while (*p) {
        if (isspace(*p)) {
            char *r = p + 1;
            char *q = r;
            *p = ' ';
            while (*q && isspace(*q))
                q++;
            if (q != (p+1))
                while ((*r++ = *q++));
        }
        p++;
    }
    ret = do_write_string(ff, s);
done:
    free(buf);
    fclose(file);
    return ret;
}

static int write_cpudesc(struct feat_fd *ff,
               struct perf_evlist *evlist __maybe_unused)
{
    const char *cpuinfo_procs[] = CPUINFO_PROC;
    unsigned int i;

    for (i = 0; i < ARRAY_SIZE(cpuinfo_procs); i++) {
        int ret;
        ret = __write_cpudesc(ff, cpuinfo_procs[i]);
        if (ret >= 0)
            return ret;
    }
    return -1;
}


static int write_nrcpus(struct feat_fd *ff,
            struct perf_evlist *evlist __maybe_unused)
{
    long nr;
    u32 nrc, nra;
    int ret;

    nrc = cpu__max_present_cpu();

    nr = sysconf(_SC_NPROCESSORS_ONLN);
    if (nr < 0)
        return -1;

    nra = (u32)(nr & UINT_MAX);

    ret = do_write(ff, &nrc, sizeof(nrc));
    if (ret < 0)
        return ret;

    return do_write(ff, &nra, sizeof(nra));
}

static int write_event_desc(struct feat_fd *ff,
                struct perf_evlist *evlist)
{
    struct perf_evsel *evsel;
    u32 nre, nri, sz;
    int ret;

    nre = evlist->nr_entries;

    /*
     * write number of events
     */
    ret = do_write(ff, &nre, sizeof(nre));
    if (ret < 0)
        return ret;

    /*
     * size of perf_event_attr struct
     */
    sz = (u32)sizeof(evsel->attr);
    ret = do_write(ff, &sz, sizeof(sz));
    if (ret < 0)
        return ret;

    evlist__for_each_entry(evlist, evsel) {
        ret = do_write(ff, &evsel->attr, sz);
        if (ret < 0)
            return ret;
        /*
         * write number of unique id per event
         * there is one id per instance of an event
         *
         * copy into an nri to be independent of the
         * type of ids,
         */
        nri = evsel->ids;
        ret = do_write(ff, &nri, sizeof(nri));
        if (ret < 0)
            return ret;

        /*
         * write event string as passed on cmdline
         */
        ret = do_write_string(ff, perf_evsel__name(evsel));
        if (ret < 0)
            return ret;
        /*
         * write unique ids for this event
         */
        ret = do_write(ff, evsel->id, evsel->ids * sizeof(u64));
        if (ret < 0)
            return ret;
    }
    return 0;
}

static int write_cmdline(struct feat_fd *ff,
             struct perf_evlist *evlist __maybe_unused)
{
    char buf[MAXPATHLEN];
    u32 n;
    int i, ret;

    /* actual path to perf binary */
    ret = readlink("/proc/self/exe", buf, sizeof(buf) - 1);
    if (ret <= 0)
        return -1;

    /* readlink() does not add null termination */
    buf[ret] = '\0';

    /* account for binary path */
    n = perf_env.nr_cmdline + 1;

    ret = do_write(ff, &n, sizeof(n));
    if (ret < 0)
        return ret;

    ret = do_write_string(ff, buf);
    if (ret < 0)
        return ret;

    for (i = 0 ; i < perf_env.nr_cmdline; i++) {
        ret = do_write_string(ff, perf_env.cmdline_argv[i]);
        if (ret < 0)
            return ret;
    }
    return 0;
}

#define CORE_SIB_FMT \
    "/sys/devices/system/cpu/cpu%d/topology/core_siblings_list"
#define THRD_SIB_FMT \
    "/sys/devices/system/cpu/cpu%d/topology/thread_siblings_list"

struct cpu_topo {
    u32 cpu_nr;
    u32 core_sib;
    u32 thread_sib;
    char **core_siblings;
    char **thread_siblings;
};

static int build_cpu_topo(struct cpu_topo *tp, int cpu)
{
    FILE *fp;
    char filename[MAXPATHLEN];
    char *buf = NULL, *p;
    size_t len = 0;
    ssize_t sret;
    u32 i = 0;
    int ret = -1;

    sprintf(filename, CORE_SIB_FMT, cpu);
    fp = fopen(filename, "r");
    if (!fp)
        goto try_threads;

    sret = getline(&buf, &len, fp);
    fclose(fp);
    if (sret <= 0)
        goto try_threads;

    p = strchr(buf, '\n');
    if (p)
        *p = '\0';

    for (i = 0; i < tp->core_sib; i++) {
        if (!strcmp(buf, tp->core_siblings[i]))
            break;
    }
    if (i == tp->core_sib) {
        tp->core_siblings[i] = buf;
        tp->core_sib++;
        buf = NULL;
        len = 0;
    }
    ret = 0;

try_threads:
    sprintf(filename, THRD_SIB_FMT, cpu);
    fp = fopen(filename, "r");
    if (!fp)
        goto done;

    if (getline(&buf, &len, fp) <= 0)
        goto done;

    p = strchr(buf, '\n');
    if (p)
        *p = '\0';

    for (i = 0; i < tp->thread_sib; i++) {
        if (!strcmp(buf, tp->thread_siblings[i]))
            break;
    }
    if (i == tp->thread_sib) {
        tp->thread_siblings[i] = buf;
        tp->thread_sib++;
        buf = NULL;
    }
    ret = 0;
done:
    if(fp)
        fclose(fp);
    free(buf);
    return ret;
}

static void free_cpu_topo(struct cpu_topo *tp)
{
    u32 i;

    if (!tp)
        return;

    for (i = 0 ; i < tp->core_sib; i++)
        zfree(&tp->core_siblings[i]);

    for (i = 0 ; i < tp->thread_sib; i++)
        zfree(&tp->thread_siblings[i]);

    free(tp);
}

static struct cpu_topo *build_cpu_topology(void)
{
    struct cpu_topo *tp = NULL;
    void *addr;
    u32 nr, i;
    size_t sz;
    long ncpus;
    int ret = -1;
    struct cpu_map *map;

    ncpus = cpu__max_present_cpu();

    /* build online CPU map */
    map = cpu_map__new(NULL);
    if (map == NULL) {
        pr_debug("failed to get system cpumap\n");
        return NULL;
    }

    nr = (u32)(ncpus & UINT_MAX);

    sz = nr * sizeof(char *);
    addr = calloc(1, sizeof(*tp) + 2 * sz);
    if (!addr)
        goto out_free;

    tp = addr;
    tp->cpu_nr = nr;
    addr += sizeof(*tp);
    tp->core_siblings = addr;
    addr += sz;
    tp->thread_siblings = addr;

    for (i = 0; i < nr; i++) {
        if (!cpu_map__has(map, i))
            continue;

        ret = build_cpu_topo(tp, i);
        if (ret < 0)
            break;
    }

out_free:
    cpu_map__put(map);
    if (ret) {
        free_cpu_topo(tp);
        tp = NULL;
    }
    return tp;
}

static int write_cpu_topology(struct feat_fd *ff,
                  struct perf_evlist *evlist __maybe_unused)
{
    struct cpu_topo *tp;
    u32 i;
    int ret, j;

    tp = build_cpu_topology();
    if (!tp)
        return -1;

    ret = do_write(ff, &tp->core_sib, sizeof(tp->core_sib));
    if (ret < 0)
        goto done;

    for (i = 0; i < tp->core_sib; i++) {
        ret = do_write_string(ff, tp->core_siblings[i]);
        if (ret < 0)
            goto done;
    }
    ret = do_write(ff, &tp->thread_sib, sizeof(tp->thread_sib));
    if (ret < 0)
        goto done;

    for (i = 0; i < tp->thread_sib; i++) {
        ret = do_write_string(ff, tp->thread_siblings[i]);
        if (ret < 0)
            break;
    }

    ret = perf_env__read_cpu_topology_map(&perf_env);
    if (ret < 0)
        goto done;

    for (j = 0; j < perf_env.nr_cpus_avail; j++) {
        ret = do_write(ff, &perf_env.cpu[j].core_id,
                   sizeof(perf_env.cpu[j].core_id));
        if (ret < 0)
            return ret;
        ret = do_write(ff, &perf_env.cpu[j].socket_id,
                   sizeof(perf_env.cpu[j].socket_id));
        if (ret < 0)
            return ret;
    }
done:
    free_cpu_topo(tp);
    return ret;
}



static int write_total_mem(struct feat_fd *ff,
               struct perf_evlist *evlist __maybe_unused)
{
    char *buf = NULL;
    FILE *fp;
    size_t len = 0;
    int ret = -1, n;
    uint64_t mem;

    fp = fopen("/proc/meminfo", "r");
    if (!fp)
        return -1;

    while (getline(&buf, &len, fp) > 0) {
        ret = strncmp(buf, "MemTotal:", 9);
        if (!ret)
            break;
    }
    if (!ret) {
        n = sscanf(buf, "%*s %"PRIu64, &mem);
        if (n == 1)
            ret = do_write(ff, &mem, sizeof(mem));
    } else
        ret = -1;
    free(buf);
    fclose(fp);
    return ret;
}

static int write_topo_node(struct feat_fd *ff, int node)
{
    char str[MAXPATHLEN];
    char field[32];
    char *buf = NULL, *p;
    size_t len = 0;
    FILE *fp;
    u64 mem_total, mem_free, mem;
    int ret = -1;

    sprintf(str, "/sys/devices/system/node/node%d/meminfo", node);
    fp = fopen(str, "r");
    if (!fp)
        return -1;

    while (getline(&buf, &len, fp) > 0) {
        /* skip over invalid lines */
        if (!strchr(buf, ':'))
            continue;
        if (sscanf(buf, "%*s %*d %31s %"PRIu64, field, &mem) != 2)
            goto done;
        if (!strcmp(field, "MemTotal:"))
            mem_total = mem;
        if (!strcmp(field, "MemFree:"))
            mem_free = mem;
    }

    fclose(fp);
    fp = NULL;

    ret = do_write(ff, &mem_total, sizeof(u64));
    if (ret)
        goto done;

    ret = do_write(ff, &mem_free, sizeof(u64));
    if (ret)
        goto done;

    ret = -1;
    sprintf(str, "/sys/devices/system/node/node%d/cpulist", node);

    fp = fopen(str, "r");
    if (!fp)
        goto done;

    if (getline(&buf, &len, fp) <= 0)
        goto done;

    p = strchr(buf, '\n');
    if (p)
        *p = '\0';

    ret = do_write_string(ff, buf);
done:
    free(buf);
    if (fp)
        fclose(fp);
    return ret;
}

static int write_numa_topology(struct feat_fd *ff,
                   struct perf_evlist *evlist __maybe_unused)
{
    char *buf = NULL;
    size_t len = 0;
    FILE *fp;
    struct cpu_map *node_map = NULL;
    char *c;
    u32 nr, i, j;
    int ret = -1;

    fp = fopen("/sys/devices/system/node/online", "r");
    if (!fp)
        return -1;

    if (getline(&buf, &len, fp) <= 0)
        goto done;

    c = strchr(buf, '\n');
    if (c)
        *c = '\0';

    node_map = cpu_map__new(buf);
    if (!node_map)
        goto done;

    nr = (u32)node_map->nr;

    ret = do_write(ff, &nr, sizeof(nr));
    if (ret < 0)
        goto done;

    for (i = 0; i < nr; i++) {
        j = (u32)node_map->map[i];
        ret = do_write(ff, &j, sizeof(j));
        if (ret < 0)
            break;

        ret = write_topo_node(ff, i);
        if (ret < 0)
            break;
    }
done:
    free(buf);
    fclose(fp);
    cpu_map__put(node_map);
    return ret;
}

/*
 * File format:
 *
 * struct pmu_mappings {
 *  u32 pmu_num;
 *  struct pmu_map {
 *      u32 type;
 *      char    name[];
 *  }[pmu_num];
 * };
 */

static int write_pmu_mappings(struct feat_fd *ff,
                  struct perf_evlist *evlist __maybe_unused)
{
    struct perf_pmu *pmu = NULL;
    u32 pmu_num = 0;
    int ret;

    /*
     * Do a first pass to count number of pmu to avoid lseek so this
     * works in pipe mode as well.
     */
    while ((pmu = perf_pmu__scan(pmu))) {
        if (!pmu->name)
            continue;
        pmu_num++;
    }

    ret = do_write(ff, &pmu_num, sizeof(pmu_num));
    if (ret < 0)
        return ret;

    while ((pmu = perf_pmu__scan(pmu))) {
        if (!pmu->name)
            continue;

        ret = do_write(ff, &pmu->type, sizeof(pmu->type));
        if (ret < 0)
            return ret;

        ret = do_write_string(ff, pmu->name);
        if (ret < 0)
            return ret;
    }

    return 0;
}

/*
 * File format:
 *
 * struct group_descs {
 *  u32 nr_groups;
 *  struct group_desc {
 *      char    name[];
 *      u32 leader_idx;
 *      u32 nr_members;
 *  }[nr_groups];
 * };
 */
static int write_group_desc(struct feat_fd *ff,
                struct perf_evlist *evlist)
{
    u32 nr_groups = evlist->nr_groups;
    struct perf_evsel *evsel;
    int ret;

    ret = do_write(ff, &nr_groups, sizeof(nr_groups));
    if (ret < 0)
        return ret;

    evlist__for_each_entry(evlist, evsel) {
        if (perf_evsel__is_group_leader(evsel) &&
            evsel->nr_members > 1) {
            const char *name = evsel->group_name ?: "{anon_group}";
            u32 leader_idx = evsel->idx;
            u32 nr_members = evsel->nr_members;

            ret = do_write_string(ff, name);
            if (ret < 0)
                return ret;

            ret = do_write(ff, &leader_idx, sizeof(leader_idx));
            if (ret < 0)
                return ret;

            ret = do_write(ff, &nr_members, sizeof(nr_members));
            if (ret < 0)
                return ret;
        }
    }
    return 0;
}

/*
 * default get_cpuid(): nothing gets recorded
 * actual implementation must be in arch/$(SRCARCH)/util/header.c
 */
int __weak get_cpuid(char *buffer __maybe_unused, size_t sz __maybe_unused)
{
    return -1;
}

static int write_cpuid(struct feat_fd *ff,
               struct perf_evlist *evlist __maybe_unused)
{
    char buffer[64];
    int ret;

    ret = get_cpuid(buffer, sizeof(buffer));
    if (!ret)
        goto write_it;

    return -1;
write_it:
    return do_write_string(ff, buffer);
}

static int write_branch_stack(struct feat_fd *ff __maybe_unused,
                  struct perf_evlist *evlist __maybe_unused)
{
    return 0;
}

static int write_auxtrace(struct feat_fd *ff,
              struct perf_evlist *evlist __maybe_unused)
{
    struct perf_session *session;
    int err;

    if (WARN(ff->buf, "Error: calling %s in pipe-mode.\n", __func__))
        return -1;

    session = container_of(ff->ph, struct perf_session, header);

    err = auxtrace_index__write(ff->fd, &session->auxtrace_index);
    if (err < 0)
        pr_err("Failed to write auxtrace index\n");
    return err;
}

static int cpu_cache_level__sort(const void *a, const void *b)
{
    struct cpu_cache_level *cache_a = (struct cpu_cache_level *)a;
    struct cpu_cache_level *cache_b = (struct cpu_cache_level *)b;

    return cache_a->level - cache_b->level;
}

static bool cpu_cache_level__cmp(struct cpu_cache_level *a, struct cpu_cache_level *b)
{
    if (a->level != b->level)
        return false;

    if (a->line_size != b->line_size)
        return false;

    if (a->sets != b->sets)
        return false;

    if (a->ways != b->ways)
        return false;

    if (strcmp(a->type, b->type))
        return false;

    if (strcmp(a->size, b->size))
        return false;

    if (strcmp(a->map, b->map))
        return false;

    return true;
}

static int cpu_cache_level__read(struct cpu_cache_level *cache, u32 cpu, u16 level)
{
    char path[PATH_MAX], file[PATH_MAX];
    struct stat st;
    size_t len;

    scnprintf(path, PATH_MAX, "devices/system/cpu/cpu%d/cache/index%d/", cpu, level);
    scnprintf(file, PATH_MAX, "%s/%s", sysfs__mountpoint(), path);

    if (stat(file, &st))
        return 1;

    scnprintf(file, PATH_MAX, "%s/level", path);
    if (sysfs__read_int(file, (int *) &cache->level))
        return -1;

    scnprintf(file, PATH_MAX, "%s/coherency_line_size", path);
    if (sysfs__read_int(file, (int *) &cache->line_size))
        return -1;

    scnprintf(file, PATH_MAX, "%s/number_of_sets", path);
    if (sysfs__read_int(file, (int *) &cache->sets))
        return -1;

    scnprintf(file, PATH_MAX, "%s/ways_of_associativity", path);
    if (sysfs__read_int(file, (int *) &cache->ways))
        return -1;

    scnprintf(file, PATH_MAX, "%s/type", path);
    if (sysfs__read_str(file, &cache->type, &len))
        return -1;

    cache->type[len] = 0;
    cache->type = rtrim(cache->type);

    scnprintf(file, PATH_MAX, "%s/size", path);
    if (sysfs__read_str(file, &cache->size, &len)) {
        free(cache->type);
        return -1;
    }

    cache->size[len] = 0;
    cache->size = rtrim(cache->size);

    scnprintf(file, PATH_MAX, "%s/shared_cpu_list", path);
    if (sysfs__read_str(file, &cache->map, &len)) {
        free(cache->map);
        free(cache->type);
        return -1;
    }

    cache->map[len] = 0;
    cache->map = rtrim(cache->map);
    return 0;
}

static void cpu_cache_level__fprintf(FILE *out, struct cpu_cache_level *c)
{
    fprintf(out, "L%d %-15s %8s [%s]\n", c->level, c->type, c->size, c->map);
}

static int build_caches(struct cpu_cache_level caches[], u32 size, u32 *cntp)
{
    u32 i, cnt = 0;
    long ncpus;
    u32 nr, cpu;
    u16 level;

    ncpus = sysconf(_SC_NPROCESSORS_CONF);
    if (ncpus < 0)
        return -1;

    nr = (u32)(ncpus & UINT_MAX);

    for (cpu = 0; cpu < nr; cpu++) {
        for (level = 0; level < 10; level++) {
            struct cpu_cache_level c;
            int err;

            err = cpu_cache_level__read(&c, cpu, level);
            if (err < 0)
                return err;

            if (err == 1)
                break;

            for (i = 0; i < cnt; i++) {
                if (cpu_cache_level__cmp(&c, &caches[i]))
                    break;
            }

            if (i == cnt)
                caches[cnt++] = c;
            else
                cpu_cache_level__free(&c);

            if (WARN_ONCE(cnt == size, "way too many cpu caches.."))
                goto out;
        }
    }
 out:
    *cntp = cnt;
    return 0;
}

#define MAX_CACHES 2000

static int write_cache(struct feat_fd *ff,
               struct perf_evlist *evlist __maybe_unused)
{
    struct cpu_cache_level caches[MAX_CACHES];
    u32 cnt = 0, i, version = 1;
    int ret;

    ret = build_caches(caches, MAX_CACHES, &cnt);
    if (ret)
        goto out;

    qsort(&caches, cnt, sizeof(struct cpu_cache_level), cpu_cache_level__sort);

    ret = do_write(ff, &version, sizeof(u32));
    if (ret < 0)
        goto out;

    ret = do_write(ff, &cnt, sizeof(u32));
    if (ret < 0)
        goto out;

    for (i = 0; i < cnt; i++) {
        struct cpu_cache_level *c = &caches[i];

        #define _W(v)                   \
            ret = do_write(ff, &c->v, sizeof(u32)); \
            if (ret < 0)                \
                goto out;

        _W(level)
        _W(line_size)
        _W(sets)
        _W(ways)
        #undef _W

        #define _W(v)                       \
            ret = do_write_string(ff, (const char *) c->v); \
            if (ret < 0)                    \
                goto out;

        _W(type)
        _W(size)
        _W(map)
        #undef _W
    }

out:
    for (i = 0; i < cnt; i++)
        cpu_cache_level__free(&caches[i]);
    return ret;
}

static int write_stat(struct feat_fd *ff __maybe_unused,
              struct perf_evlist *evlist __maybe_unused)
{
    return 0;
}

static int write_sample_time(struct feat_fd *ff,
                 struct perf_evlist *evlist)
{
    int ret;

    ret = do_write(ff, &evlist->first_sample_time,
               sizeof(evlist->first_sample_time));
    if (ret < 0)
        return ret;

    return do_write(ff, &evlist->last_sample_time,
            sizeof(evlist->last_sample_time));
}


static int memory_node__read(struct memory_node *n, unsigned long idx)
{
    unsigned int phys, size = 0;
    char path[PATH_MAX];
    struct dirent *ent;
    DIR *dir;

#define for_each_memory(mem, dir)                   \
    while ((ent = readdir(dir)))                    \
        if (strcmp(ent->d_name, ".") &&             \
            strcmp(ent->d_name, "..") &&            \
            sscanf(ent->d_name, "memory%u", &mem) == 1)

    scnprintf(path, PATH_MAX,
          "%s/devices/system/node/node%lu",
          sysfs__mountpoint(), idx);

    dir = opendir(path);
    if (!dir) {
        pr_warning("failed: cant' open memory sysfs data\n");
        return -1;
    }

    for_each_memory(phys, dir) {
        size = max(phys, size);
    }

    size++;

    n->set = bitmap_alloc(size);
    if (!n->set) {
        closedir(dir);
        return -ENOMEM;
    }

    bitmap_zero(n->set, size);
    n->node = idx;
    n->size = size;

    rewinddir(dir);

    for_each_memory(phys, dir) {
        set_bit(phys, n->set);
    }

    closedir(dir);
    return 0;
}

static int memory_node__sort(const void *a, const void *b)
{
    const struct memory_node *na = a;
    const struct memory_node *nb = b;

    return na->node - nb->node;
}

static int build_mem_topology(struct memory_node *nodes, u64 size, u64 *cntp)
{
    char path[PATH_MAX];
    struct dirent *ent;
    DIR *dir;
    u64 cnt = 0;
    int ret = 0;

    scnprintf(path, PATH_MAX, "%s/devices/system/node/",
          sysfs__mountpoint());

    dir = opendir(path);
    if (!dir) {
        pr_debug2("%s: could't read %s, does this arch have topology information?\n",
              __func__, path);
        return -1;
    }

    while (!ret && (ent = readdir(dir))) {
        unsigned int idx;
        int r;

        if (!strcmp(ent->d_name, ".") ||
            !strcmp(ent->d_name, ".."))
            continue;

        r = sscanf(ent->d_name, "node%u", &idx);
        if (r != 1)
            continue;

        if (WARN_ONCE(cnt >= size,
                  "failed to write MEM_TOPOLOGY, way too many nodes\n"))
            return -1;

        ret = memory_node__read(&nodes[cnt++], idx);
    }

    *cntp = cnt;
    closedir(dir);

    if (!ret)
        qsort(nodes, cnt, sizeof(nodes[0]), memory_node__sort);

    return ret;
}

#define MAX_MEMORY_NODES 2000

/*
 * The MEM_TOPOLOGY holds physical memory map for every
 * node in system. The format of data is as follows:
 *
 *  0 - version          | for future changes
 *  8 - block_size_bytes | /sys/devices/system/memory/block_size_bytes
 * 16 - count            | number of nodes
 *
 * For each node we store map of physical indexes for
 * each node:
 *
 * 32 - node id          | node index
 * 40 - size             | size of bitmap
 * 48 - bitmap           | bitmap of memory indexes that belongs to node
 */
static int write_mem_topology(struct feat_fd *ff __maybe_unused,
                  struct perf_evlist *evlist __maybe_unused)
{
    static struct memory_node nodes[MAX_MEMORY_NODES];
    u64 bsize, version = 1, i, nr;
    int ret;

    ret = sysfs__read_xll("devices/system/memory/block_size_bytes",
                  (unsigned long long *) &bsize);
    if (ret)
        return ret;

    ret = build_mem_topology(&nodes[0], MAX_MEMORY_NODES, &nr);
    if (ret)
        return ret;

    ret = do_write(ff, &version, sizeof(version));
    if (ret < 0)
        goto out;

    ret = do_write(ff, &bsize, sizeof(bsize));
    if (ret < 0)
        goto out;

    ret = do_write(ff, &nr, sizeof(nr));
    if (ret < 0)
        goto out;

    for (i = 0; i < nr; i++) {
        struct memory_node *n = &nodes[i];

        #define _W(v)                       \
            ret = do_write(ff, &n->v, sizeof(n->v));    \
            if (ret < 0)                    \
                goto out;

        _W(node)
        _W(size)

        #undef _W

        ret = do_write_bitmap(ff, n->set, n->size);
        if (ret < 0)
            goto out;
    }

out:
    return ret;
}

static void print_hostname(struct feat_fd *ff, FILE *fp)
{
    fprintf(fp, "# hostname : %s\n", ff->ph->env.hostname);
}

static void print_osrelease(struct feat_fd *ff, FILE *fp)
{
    fprintf(fp, "# os release : %s\n", ff->ph->env.os_release);
}

static void print_arch(struct feat_fd *ff, FILE *fp)
{
    fprintf(fp, "# arch : %s\n", ff->ph->env.arch);
}

static void print_cpudesc(struct feat_fd *ff, FILE *fp)
{
    fprintf(fp, "# cpudesc : %s\n", ff->ph->env.cpu_desc);
}

static void print_nrcpus(struct feat_fd *ff, FILE *fp)
{
    fprintf(fp, "# nrcpus online : %u\n", ff->ph->env.nr_cpus_online);
    fprintf(fp, "# nrcpus avail : %u\n", ff->ph->env.nr_cpus_avail);
}

static void print_version(struct feat_fd *ff, FILE *fp)
{
    fprintf(fp, "# perf version : %s\n", ff->ph->env.version);
}

static void print_cmdline(struct feat_fd *ff, FILE *fp)
{
    int nr, i;

    nr = ff->ph->env.nr_cmdline;

    fprintf(fp, "# cmdline : ");

    for (i = 0; i < nr; i++) {
        char *argv_i = strdup(ff->ph->env.cmdline_argv[i]);
        if (!argv_i) {
            fprintf(fp, "%s ", ff->ph->env.cmdline_argv[i]);
        } else {
            char *mem = argv_i;
            do {
                char *quote = strchr(argv_i, '\'');
                if (!quote)
                    break;
                *quote++ = '\0';
                fprintf(fp, "%s\\\'", argv_i);
                argv_i = quote;
            } while (1);
            fprintf(fp, "%s ", argv_i);
            free(mem);
        }
    }
    fputc('\n', fp);
}

static void print_cpu_topology(struct feat_fd *ff, FILE *fp)
{
    struct perf_header *ph = ff->ph;
    int cpu_nr = ph->env.nr_cpus_avail;
    int nr, i;
    char *str;

    nr = ph->env.nr_sibling_cores;
    str = ph->env.sibling_cores;

    for (i = 0; i < nr; i++) {
        fprintf(fp, "# sibling cores   : %s\n", str);
        str += strlen(str) + 1;
    }

    nr = ph->env.nr_sibling_threads;
    str = ph->env.sibling_threads;

    for (i = 0; i < nr; i++) {
        fprintf(fp, "# sibling threads : %s\n", str);
        str += strlen(str) + 1;
    }

    if (ph->env.cpu != NULL) {
        for (i = 0; i < cpu_nr; i++)
            fprintf(fp, "# CPU %d: Core ID %d, Socket ID %d\n", i,
                ph->env.cpu[i].core_id, ph->env.cpu[i].socket_id);
    } else
        fprintf(fp, "# Core ID and Socket ID information is not available\n");
}

static void free_event_desc(struct perf_evsel *events)
{
    struct perf_evsel *evsel;

    if (!events)
        return;

    for (evsel = events; evsel->attr.size; evsel++) {
        zfree(&evsel->name);
        zfree(&evsel->id);
    }

    free(events);
}

static struct perf_evsel *read_event_desc(struct feat_fd *ff)
{
    struct perf_evsel *evsel, *events = NULL;
    u64 *id;
    void *buf = NULL;
    u32 nre, sz, nr, i, j;
    size_t msz;

    /* number of events */
    if (do_read_u32(ff, &nre))
        goto error;

    if (do_read_u32(ff, &sz))
        goto error;

    /* buffer to hold on file attr struct */
    buf = malloc(sz);
    if (!buf)
        goto error;

    /* the last event terminates with evsel->attr.size == 0: */
    events = calloc(nre + 1, sizeof(*events));
    if (!events)
        goto error;

    msz = sizeof(evsel->attr);
    if (sz < msz)
        msz = sz;

    for (i = 0, evsel = events; i < nre; evsel++, i++) {
        evsel->idx = i;

        /*
         * must read entire on-file attr struct to
         * sync up with layout.
         */
        if (__do_read(ff, buf, sz))
            goto error;

        if (ff->ph->needs_swap)
            perf_event__attr_swap(buf);

        memcpy(&evsel->attr, buf, msz);

        if (do_read_u32(ff, &nr))
            goto error;

        if (ff->ph->needs_swap)
            evsel->needs_swap = true;

        evsel->name = do_read_string(ff);
        if (!evsel->name)
            goto error;

        if (!nr)
            continue;

        id = calloc(nr, sizeof(*id));
        if (!id)
            goto error;
        evsel->ids = nr;
        evsel->id = id;

        for (j = 0 ; j < nr; j++) {
            if (do_read_u64(ff, id))
                goto error;
            id++;
        }
    }
out:
    free(buf);
    return events;
error:
    free_event_desc(events);
    events = NULL;
    goto out;
}

static int __desc_attr__fprintf(FILE *fp, const char *name, const char *val,
                void *priv __maybe_unused)
{
    return fprintf(fp, ", %s = %s", name, val);
}

static void print_event_desc(struct feat_fd *ff, FILE *fp)
{
    struct perf_evsel *evsel, *events;
    u32 j;
    u64 *id;

    if (ff->events)
        events = ff->events;
    else
        events = read_event_desc(ff);

    if (!events) {
        fprintf(fp, "# event desc: not available or unable to read\n");
        return;
    }

    for (evsel = events; evsel->attr.size; evsel++) {
        fprintf(fp, "# event : name = %s, ", evsel->name);

        if (evsel->ids) {
            fprintf(fp, ", id = {");
            for (j = 0, id = evsel->id; j < evsel->ids; j++, id++) {
                if (j)
                    fputc(',', fp);
                fprintf(fp, " %"PRIu64, *id);
            }
            fprintf(fp, " }");
        }

        perf_event_attr__fprintf(fp, &evsel->attr, __desc_attr__fprintf, NULL);

        fputc('\n', fp);
    }

    free_event_desc(events);
    ff->events = NULL;
}

static void print_total_mem(struct feat_fd *ff, FILE *fp)
{
    fprintf(fp, "# total memory : %llu kB\n", ff->ph->env.total_mem);
}

static void print_numa_topology(struct feat_fd *ff, FILE *fp)
{
    int i;
    struct numa_node *n;

    for (i = 0; i < ff->ph->env.nr_numa_nodes; i++) {
        n = &ff->ph->env.numa_nodes[i];

        fprintf(fp, "# node%u meminfo  : total = %"PRIu64" kB,"
                " free = %"PRIu64" kB\n",
            n->node, n->mem_total, n->mem_free);

        fprintf(fp, "# node%u cpu list : ", n->node);
        cpu_map__fprintf(n->map, fp);
    }
}

static void print_cpuid(struct feat_fd *ff, FILE *fp)
{
    fprintf(fp, "# cpuid : %s\n", ff->ph->env.cpuid);
}

static void print_branch_stack(struct feat_fd *ff __maybe_unused, FILE *fp)
{
    fprintf(fp, "# contains samples with branch stack\n");
}

static void print_auxtrace(struct feat_fd *ff __maybe_unused, FILE *fp)
{
    fprintf(fp, "# contains AUX area data (e.g. instruction trace)\n");
}

static void print_stat(struct feat_fd *ff __maybe_unused, FILE *fp)
{
    fprintf(fp, "# contains stat data\n");
}

static void print_cache(struct feat_fd *ff, FILE *fp __maybe_unused)
{
    int i;

    fprintf(fp, "# CPU cache info:\n");
    for (i = 0; i < ff->ph->env.caches_cnt; i++) {
        fprintf(fp, "#  ");
        cpu_cache_level__fprintf(fp, &ff->ph->env.caches[i]);
    }
}

static void print_pmu_mappings(struct feat_fd *ff, FILE *fp)
{
    const char *delimiter = "# pmu mappings: ";
    char *str, *tmp;
    u32 pmu_num;
    u32 type;

    pmu_num = ff->ph->env.nr_pmu_mappings;
    if (!pmu_num) {
        fprintf(fp, "# pmu mappings: not available\n");
        return;
    }

    str = ff->ph->env.pmu_mappings;

    while (pmu_num) {
        type = strtoul(str, &tmp, 0);
        if (*tmp != ':')
            goto error;

        str = tmp + 1;
        fprintf(fp, "%s%s = %" PRIu32, delimiter, str, type);

        delimiter = ", ";
        str += strlen(str) + 1;
        pmu_num--;
    }

    fprintf(fp, "\n");

    if (!pmu_num)
        return;
error:
    fprintf(fp, "# pmu mappings: unable to read\n");
}

static void print_group_desc(struct feat_fd *ff, FILE *fp)
{
    struct perf_session *session;
    struct perf_evsel *evsel;
    u32 nr = 0;

    session = container_of(ff->ph, struct perf_session, header);

    evlist__for_each_entry(session->evlist, evsel) {
        if (perf_evsel__is_group_leader(evsel) &&
            evsel->nr_members > 1) {
            fprintf(fp, "# group: %s{%s", evsel->group_name ?: "",
                perf_evsel__name(evsel));

            nr = evsel->nr_members - 1;
        } else if (nr) {
            fprintf(fp, ",%s", perf_evsel__name(evsel));

            if (--nr == 0)
                fprintf(fp, "}\n");
        }
    }
}

static void print_sample_time(struct feat_fd *ff, FILE *fp)
{
    struct perf_session *session;
    char time_buf[32];
    double d;

    session = container_of(ff->ph, struct perf_session, header);

    timestamp__scnprintf_usec(session->evlist->first_sample_time,
                  time_buf, sizeof(time_buf));
    fprintf(fp, "# time of first sample : %s\n", time_buf);

    timestamp__scnprintf_usec(session->evlist->last_sample_time,
                  time_buf, sizeof(time_buf));
    fprintf(fp, "# time of last sample : %s\n", time_buf);

    d = (double)(session->evlist->last_sample_time -
        session->evlist->first_sample_time) / NSEC_PER_MSEC;

    fprintf(fp, "# sample duration : %10.3f ms\n", d);
}

static void memory_node__fprintf(struct memory_node *n,
                 unsigned long long bsize, FILE *fp)
{
    char buf_map[100], buf_size[50];
    unsigned long long size;

    size = bsize * bitmap_weight(n->set, n->size);
    unit_number__scnprintf(buf_size, 50, size);

    bitmap_scnprintf(n->set, n->size, buf_map, 100);
    fprintf(fp, "#  %3" PRIu64 " [%s]: %s\n", n->node, buf_size, buf_map);
}

static void print_mem_topology(struct feat_fd *ff, FILE *fp)
{
    struct memory_node *nodes;
    int i, nr;

    nodes = ff->ph->env.memory_nodes;
    nr    = ff->ph->env.nr_memory_nodes;

    fprintf(fp, "# memory nodes (nr %d, block size 0x%llx):\n",
        nr, ff->ph->env.memory_bsize);

    for (i = 0; i < nr; i++) {
        memory_node__fprintf(&nodes[i], ff->ph->env.memory_bsize, fp);
    }
}

static int __event_process_build_id(struct build_id_event *bev,
                    char *filename,
                    struct perf_session *session)
{
    int err = -1;
    struct machine *machine;
    u16 cpumode;
    struct dso *dso;
    enum dso_kernel_type dso_type;

    machine = perf_session__findnew_machine(session, bev->pid);
    if (!machine)
        goto out;

    cpumode = bev->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;

    switch (cpumode) {
    case PERF_RECORD_MISC_KERNEL:
        dso_type = DSO_TYPE_KERNEL;
        break;
    case PERF_RECORD_MISC_GUEST_KERNEL:
        dso_type = DSO_TYPE_GUEST_KERNEL;
        break;
    case PERF_RECORD_MISC_USER:
    case PERF_RECORD_MISC_GUEST_USER:
        dso_type = DSO_TYPE_USER;
        break;
    default:
        goto out;
    }

    dso = machine__findnew_dso(machine, filename);
    if (dso != NULL) {
        char sbuild_id[SBUILD_ID_SIZE];

        dso__set_build_id(dso, &bev->build_id);

        if (dso_type != DSO_TYPE_USER) {
            struct kmod_path m = { .name = NULL, };

            if (!kmod_path__parse_name(&m, filename) && m.kmod)
                dso__set_module_info(dso, &m, machine);
            else
                dso->kernel = dso_type;

            free(m.name);
        }

        build_id__sprintf(dso->build_id, sizeof(dso->build_id),
                  sbuild_id);
        pr_debug("build id event received for %s: %s\n",
             dso->long_name, sbuild_id);
        dso__put(dso);
    }

    err = 0;
out:
    return err;
}

static int perf_header__read_build_ids_abi_quirk(struct perf_header *header,
                         int input, u64 offset, u64 size)
{
    struct perf_session *session = container_of(header, struct perf_session, header);
    struct {
        struct perf_event_header   header;
        u8             build_id[PERF_ALIGN(BUILD_ID_SIZE, sizeof(u64))];
        char               filename[0];
    } old_bev;
    struct build_id_event bev;
    char filename[PATH_MAX];
    u64 limit = offset + size;

    while (offset < limit) {
        ssize_t len;

        if (readn(input, &old_bev, sizeof(old_bev)) != sizeof(old_bev))
            return -1;

        if (header->needs_swap)
            perf_event_header__bswap(&old_bev.header);

        len = old_bev.header.size - sizeof(old_bev);
        if (readn(input, filename, len) != len)
            return -1;

        bev.header = old_bev.header;

        /*
         * As the pid is the missing value, we need to fill
         * it properly. The header.misc value give us nice hint.
         */
        bev.pid = HOST_KERNEL_ID;
        if (bev.header.misc == PERF_RECORD_MISC_GUEST_USER ||
            bev.header.misc == PERF_RECORD_MISC_GUEST_KERNEL)
            bev.pid = DEFAULT_GUEST_KERNEL_ID;

        memcpy(bev.build_id, old_bev.build_id, sizeof(bev.build_id));
        __event_process_build_id(&bev, filename, session);

        offset += bev.header.size;
    }

    return 0;
}

static int perf_header__read_build_ids(struct perf_header *header,
                       int input, u64 offset, u64 size)
{
    struct perf_session *session = container_of(header, struct perf_session, header);
    struct build_id_event bev;
    char filename[PATH_MAX];
    u64 limit = offset + size, orig_offset = offset;
    int err = -1;

    while (offset < limit) {
        ssize_t len;

        if (readn(input, &bev, sizeof(bev)) != sizeof(bev))
            goto out;

        if (header->needs_swap)
            perf_event_header__bswap(&bev.header);

        len = bev.header.size - sizeof(bev);
        if (readn(input, filename, len) != len)
            goto out;
        /*
         * The a1645ce1 changeset:
         *
         * "perf: 'perf kvm' tool for monitoring guest performance from host"
         *
         * Added a field to struct build_id_event that broke the file
         * format.
         *
         * Since the kernel build-id is the first entry, process the
         * table using the old format if the well known
         * '[kernel.kallsyms]' string for the kernel build-id has the
         * first 4 characters chopped off (where the pid_t sits).
         */
        if (memcmp(filename, "nel.kallsyms]", 13) == 0) {
            if (lseek(input, orig_offset, SEEK_SET) == (off_t)-1)
                return -1;
            return perf_header__read_build_ids_abi_quirk(header, input, offset, size);
        }

        __event_process_build_id(&bev, filename, session);

        offset += bev.header.size;
    }
    err = 0;
out:
    return err;
}

/* Macro for features that simply need to read and store a string. */
#define FEAT_PROCESS_STR_FUN(__feat, __feat_env) \
static int process_##__feat(struct feat_fd *ff, void *data __maybe_unused) \
{\
    ff->ph->env.__feat_env = do_read_string(ff); \
    return ff->ph->env.__feat_env ? 0 : -ENOMEM; \
}

FEAT_PROCESS_STR_FUN(hostname, hostname);
FEAT_PROCESS_STR_FUN(osrelease, os_release);
FEAT_PROCESS_STR_FUN(version, version);
FEAT_PROCESS_STR_FUN(arch, arch);
FEAT_PROCESS_STR_FUN(cpudesc, cpu_desc);
FEAT_PROCESS_STR_FUN(cpuid, cpuid);

static int process_tracing_data(struct feat_fd *ff, void *data)
{
    ssize_t ret = trace_report(ff->fd, data, false);

    return ret < 0 ? -1 : 0;
}

static int process_build_id(struct feat_fd *ff, void *data __maybe_unused)
{
    if (perf_header__read_build_ids(ff->ph, ff->fd, ff->offset, ff->size))
        pr_debug("Failed to read buildids, continuing...\n");
    return 0;
}

static int process_nrcpus(struct feat_fd *ff, void *data __maybe_unused)
{
    int ret;
    u32 nr_cpus_avail, nr_cpus_online;

    ret = do_read_u32(ff, &nr_cpus_avail);
    if (ret)
        return ret;

    ret = do_read_u32(ff, &nr_cpus_online);
    if (ret)
        return ret;
    ff->ph->env.nr_cpus_avail = (int)nr_cpus_avail;
    ff->ph->env.nr_cpus_online = (int)nr_cpus_online;
    return 0;
}

static int process_total_mem(struct feat_fd *ff, void *data __maybe_unused)
{
    u64 total_mem;
    int ret;

    ret = do_read_u64(ff, &total_mem);
    if (ret)
        return -1;
    ff->ph->env.total_mem = (unsigned long long)total_mem;
    return 0;
}

static struct perf_evsel *
perf_evlist__find_by_index(struct perf_evlist *evlist, int idx)
{
    struct perf_evsel *evsel;

    evlist__for_each_entry(evlist, evsel) {
        if (evsel->idx == idx)
            return evsel;
    }

    return NULL;
}

static void
perf_evlist__set_event_name(struct perf_evlist *evlist,
                struct perf_evsel *event)
{
    struct perf_evsel *evsel;

    if (!event->name)
        return;

    evsel = perf_evlist__find_by_index(evlist, event->idx);
    if (!evsel)
        return;

    if (evsel->name)
        return;

    evsel->name = strdup(event->name);
}

static int
process_event_desc(struct feat_fd *ff, void *data __maybe_unused)
{
    struct perf_session *session;
    struct perf_evsel *evsel, *events = read_event_desc(ff);

    if (!events)
        return 0;

    session = container_of(ff->ph, struct perf_session, header);

    if (session->data->is_pipe) {
        /* Save events for reading later by print_event_desc,
         * since they can't be read again in pipe mode. */
        ff->events = events;
    }

    for (evsel = events; evsel->attr.size; evsel++)
        perf_evlist__set_event_name(session->evlist, evsel);

    if (!session->data->is_pipe)
        free_event_desc(events);

    return 0;
}

static int process_cmdline(struct feat_fd *ff, void *data __maybe_unused)
{
    char *str, *cmdline = NULL, **argv = NULL;
    u32 nr, i, len = 0;

    if (do_read_u32(ff, &nr))
        return -1;

    ff->ph->env.nr_cmdline = nr;

    cmdline = zalloc(ff->size + nr + 1);
    if (!cmdline)
        return -1;

    argv = zalloc(sizeof(char *) * (nr + 1));
    if (!argv)
        goto error;

    for (i = 0; i < nr; i++) {
        str = do_read_string(ff);
        if (!str)
            goto error;

        argv[i] = cmdline + len;
        memcpy(argv[i], str, strlen(str) + 1);
        len += strlen(str) + 1;
        free(str);
    }
    ff->ph->env.cmdline = cmdline;
    ff->ph->env.cmdline_argv = (const char **) argv;
    return 0;

error:
    free(argv);
    free(cmdline);
    return -1;
}

static int process_cpu_topology(struct feat_fd *ff, void *data __maybe_unused)
{
    u32 nr, i;
    char *str;
    struct strbuf sb;
    int cpu_nr = ff->ph->env.nr_cpus_avail;
    u64 size = 0;
    struct perf_header *ph = ff->ph;

    ph->env.cpu = calloc(cpu_nr, sizeof(*ph->env.cpu));
    if (!ph->env.cpu)
        return -1;

    if (do_read_u32(ff, &nr))
        goto free_cpu;

    ph->env.nr_sibling_cores = nr;
    size += sizeof(u32);
    if (strbuf_init(&sb, 128) < 0)
        goto free_cpu;

    for (i = 0; i < nr; i++) {
        str = do_read_string(ff);
        if (!str)
            goto error;

        /* include a NULL character at the end */
        if (strbuf_add(&sb, str, strlen(str) + 1) < 0)
            goto error;
        size += string_size(str);
        free(str);
    }
    ph->env.sibling_cores = strbuf_detach(&sb, NULL);

    if (do_read_u32(ff, &nr))
        return -1;

    ph->env.nr_sibling_threads = nr;
    size += sizeof(u32);

    for (i = 0; i < nr; i++) {
        str = do_read_string(ff);
        if (!str)
            goto error;

        /* include a NULL character at the end */
        if (strbuf_add(&sb, str, strlen(str) + 1) < 0)
            goto error;
        size += string_size(str);
        free(str);
    }
    ph->env.sibling_threads = strbuf_detach(&sb, NULL);

    /*
     * The header may be from old perf,
     * which doesn't include core id and socket id information.
     */
    if (ff->size <= size) {
        zfree(&ph->env.cpu);
        return 0;
    }

    for (i = 0; i < (u32)cpu_nr; i++) {
        if (do_read_u32(ff, &nr))
            goto free_cpu;

        ph->env.cpu[i].core_id = nr;

        if (do_read_u32(ff, &nr))
            goto free_cpu;

        if (nr != (u32)-1 && nr > (u32)cpu_nr) {
            pr_debug("socket_id number is too big."
                 "You may need to upgrade the perf tool.\n");
            goto free_cpu;
        }

        ph->env.cpu[i].socket_id = nr;
    }

    return 0;

error:
    strbuf_release(&sb);
free_cpu:
    zfree(&ph->env.cpu);
    return -1;
}

static int process_numa_topology(struct feat_fd *ff, void *data __maybe_unused)
{
    struct numa_node *nodes, *n;
    u32 nr, i;
    char *str;

    /* nr nodes */
    if (do_read_u32(ff, &nr))
        return -1;

    nodes = zalloc(sizeof(*nodes) * nr);
    if (!nodes)
        return -ENOMEM;

    for (i = 0; i < nr; i++) {
        n = &nodes[i];

        /* node number */
        if (do_read_u32(ff, &n->node))
            goto error;

        if (do_read_u64(ff, &n->mem_total))
            goto error;

        if (do_read_u64(ff, &n->mem_free))
            goto error;

        str = do_read_string(ff);
        if (!str)
            goto error;

        n->map = cpu_map__new(str);
        if (!n->map)
            goto error;

        free(str);
    }
    ff->ph->env.nr_numa_nodes = nr;
    ff->ph->env.numa_nodes = nodes;
    return 0;

error:
    free(nodes);
    return -1;
}

static int process_pmu_mappings(struct feat_fd *ff, void *data __maybe_unused)
{
    char *name;
    u32 pmu_num;
    u32 type;
    struct strbuf sb;

    if (do_read_u32(ff, &pmu_num))
        return -1;

    if (!pmu_num) {
        pr_debug("pmu mappings not available\n");
        return 0;
    }

    ff->ph->env.nr_pmu_mappings = pmu_num;
    if (strbuf_init(&sb, 128) < 0)
        return -1;

    while (pmu_num) {
        if (do_read_u32(ff, &type))
            goto error;

        name = do_read_string(ff);
        if (!name)
            goto error;

        if (strbuf_addf(&sb, "%u:%s", type, name) < 0)
            goto error;
        /* include a NULL character at the end */
        if (strbuf_add(&sb, "", 1) < 0)
            goto error;

        if (!strcmp(name, "msr"))
            ff->ph->env.msr_pmu_type = type;

        free(name);
        pmu_num--;
    }
    ff->ph->env.pmu_mappings = strbuf_detach(&sb, NULL);
    return 0;

error:
    strbuf_release(&sb);
    return -1;
}

static int process_group_desc(struct feat_fd *ff, void *data __maybe_unused)
{
    size_t ret = -1;
    u32 i, nr, nr_groups;
    struct perf_session *session;
    struct perf_evsel *evsel, *leader = NULL;
    struct group_desc {
        char *name;
        u32 leader_idx;
        u32 nr_members;
    } *desc;

    if (do_read_u32(ff, &nr_groups))
        return -1;

    ff->ph->env.nr_groups = nr_groups;
    if (!nr_groups) {
        pr_debug("group desc not available\n");
        return 0;
    }

    desc = calloc(nr_groups, sizeof(*desc));
    if (!desc)
        return -1;

    for (i = 0; i < nr_groups; i++) {
        desc[i].name = do_read_string(ff);
        if (!desc[i].name)
            goto out_free;

        if (do_read_u32(ff, &desc[i].leader_idx))
            goto out_free;

        if (do_read_u32(ff, &desc[i].nr_members))
            goto out_free;
    }

    /*
     * Rebuild group relationship based on the group_desc
     */
    session = container_of(ff->ph, struct perf_session, header);
    session->evlist->nr_groups = nr_groups;

    i = nr = 0;
    evlist__for_each_entry(session->evlist, evsel) {
        if (evsel->idx == (int) desc[i].leader_idx) {
            evsel->leader = evsel;
            /* {anon_group} is a dummy name */
            if (strcmp(desc[i].name, "{anon_group}")) {
                evsel->group_name = desc[i].name;
                desc[i].name = NULL;
            }
            evsel->nr_members = desc[i].nr_members;

            if (i >= nr_groups || nr > 0) {
                pr_debug("invalid group desc\n");
                goto out_free;
            }

            leader = evsel;
            nr = evsel->nr_members - 1;
            i++;
        } else if (nr) {
            /* This is a group member */
            evsel->leader = leader;

            nr--;
        }
    }

    if (i != nr_groups || nr != 0) {
        pr_debug("invalid group desc\n");
        goto out_free;
    }

    ret = 0;
out_free:
    for (i = 0; i < nr_groups; i++)
        zfree(&desc[i].name);
    free(desc);

    return ret;
}

static int process_auxtrace(struct feat_fd *ff, void *data __maybe_unused)
{
    struct perf_session *session;
    int err;

    session = container_of(ff->ph, struct perf_session, header);

    err = auxtrace_index__process(ff->fd, ff->size, session,
                      ff->ph->needs_swap);
    if (err < 0)
        pr_err("Failed to process auxtrace index\n");
    return err;
}

static int process_cache(struct feat_fd *ff, void *data __maybe_unused)
{
    struct cpu_cache_level *caches;
    u32 cnt, i, version;

    if (do_read_u32(ff, &version))
        return -1;

    if (version != 1)
        return -1;

    if (do_read_u32(ff, &cnt))
        return -1;

    caches = zalloc(sizeof(*caches) * cnt);
    if (!caches)
        return -1;

    for (i = 0; i < cnt; i++) {
        struct cpu_cache_level c;

        #define _R(v)                       \
            if (do_read_u32(ff, &c.v))\
                goto out_free_caches;           \

        _R(level)
        _R(line_size)
        _R(sets)
        _R(ways)
        #undef _R

        #define _R(v)                   \
            c.v = do_read_string(ff);       \
            if (!c.v)               \
                goto out_free_caches;

        _R(type)
        _R(size)
        _R(map)
        #undef _R

        caches[i] = c;
    }

    ff->ph->env.caches = caches;
    ff->ph->env.caches_cnt = cnt;
    return 0;
out_free_caches:
    free(caches);
    return -1;
}

static int process_sample_time(struct feat_fd *ff, void *data __maybe_unused)
{
    struct perf_session *session;
    u64 first_sample_time, last_sample_time;
    int ret;

    session = container_of(ff->ph, struct perf_session, header);

    ret = do_read_u64(ff, &first_sample_time);
    if (ret)
        return -1;

    ret = do_read_u64(ff, &last_sample_time);
    if (ret)
        return -1;

    session->evlist->first_sample_time = first_sample_time;
    session->evlist->last_sample_time = last_sample_time;
    return 0;
}

static int process_mem_topology(struct feat_fd *ff,
                void *data __maybe_unused)
{
    struct memory_node *nodes;
    u64 version, i, nr, bsize;
    int ret = -1;

    if (do_read_u64(ff, &version))
        return -1;

    if (version != 1)
        return -1;

    if (do_read_u64(ff, &bsize))
        return -1;

    if (do_read_u64(ff, &nr))
        return -1;

    nodes = zalloc(sizeof(*nodes) * nr);
    if (!nodes)
        return -1;

    for (i = 0; i < nr; i++) {
        struct memory_node n;

        #define _R(v)               \
            if (do_read_u64(ff, &n.v))  \
                goto out;       \

        _R(node)
        _R(size)

        #undef _R

        if (do_read_bitmap(ff, &n.set, &n.size))
            goto out;

        nodes[i] = n;
    }

    ff->ph->env.memory_bsize    = bsize;
    ff->ph->env.memory_nodes    = nodes;
    ff->ph->env.nr_memory_nodes = nr;
    ret = 0;

out:
    if (ret)
        free(nodes);
    return ret;
}

struct feature_ops {
    int (*write)(struct feat_fd *ff, struct perf_evlist *evlist);
    void (*print)(struct feat_fd *ff, FILE *fp);
    int (*process)(struct feat_fd *ff, void *data);
    const char *name;
    bool full_only;
    bool synthesize;
};

#define FEAT_OPR(n, func, __full_only) \
    [HEADER_##n] = {                    \
        .name       = __stringify(n),           \
        .write      = write_##func,         \
        .print      = print_##func,         \
        .full_only  = __full_only,          \
        .process    = process_##func,           \
        .synthesize = true              \
    }

#define FEAT_OPN(n, func, __full_only) \
    [HEADER_##n] = {                    \
        .name       = __stringify(n),           \
        .write      = write_##func,         \
        .print      = print_##func,         \
        .full_only  = __full_only,          \
        .process    = process_##func            \
    }

/* feature_ops not implemented: */
#define print_tracing_data  NULL
#define print_build_id      NULL

#define process_branch_stack    NULL
#define process_stat        NULL


static const struct feature_ops feat_ops[HEADER_LAST_FEATURE] = {
    FEAT_OPN(TRACING_DATA,  tracing_data,   false),
    FEAT_OPN(BUILD_ID,  build_id,   false),
    FEAT_OPR(HOSTNAME,  hostname,   false),
    FEAT_OPR(OSRELEASE, osrelease,  false),
    FEAT_OPR(VERSION,   version,    false),
    FEAT_OPR(ARCH,      arch,       false),
    FEAT_OPR(NRCPUS,    nrcpus,     false),
    FEAT_OPR(CPUDESC,   cpudesc,    false),
    FEAT_OPR(CPUID,     cpuid,      false),
    FEAT_OPR(TOTAL_MEM, total_mem,  false),
    FEAT_OPR(EVENT_DESC,    event_desc, false),
    FEAT_OPR(CMDLINE,   cmdline,    false),
    FEAT_OPR(CPU_TOPOLOGY,  cpu_topology,   true),
    FEAT_OPR(NUMA_TOPOLOGY, numa_topology,  true),
    FEAT_OPN(BRANCH_STACK,  branch_stack,   false),
    FEAT_OPR(PMU_MAPPINGS,  pmu_mappings,   false),
    FEAT_OPN(GROUP_DESC,    group_desc, false),
    FEAT_OPN(AUXTRACE,  auxtrace,   false),
    FEAT_OPN(STAT,      stat,       false),
    FEAT_OPN(CACHE,     cache,      true),
    FEAT_OPR(SAMPLE_TIME,   sample_time,    false),
    FEAT_OPR(MEM_TOPOLOGY,  mem_topology,   true),
};

struct header_print_data {
    FILE *fp;
    bool full; /* extended list of headers */
};

static int perf_file_section__fprintf_info(struct perf_file_section *section,
                       struct perf_header *ph,
                       int feat, int fd, void *data)
{
    struct header_print_data *hd = data;
    struct feat_fd ff;

    if (lseek(fd, section->offset, SEEK_SET) == (off_t)-1) {
        pr_debug("Failed to lseek to %" PRIu64 " offset for feature "
                "%d, continuing...\n", section->offset, feat);
        return 0;
    }
    if (feat >= HEADER_LAST_FEATURE) {
        pr_warning("unknown feature %d\n", feat);
        return 0;
    }
    if (!feat_ops[feat].print)
        return 0;

    ff = (struct  feat_fd) {
        .fd = fd,
        .ph = ph,
    };

    if (!feat_ops[feat].full_only || hd->full)
        feat_ops[feat].print(&ff, hd->fp);
    else
        fprintf(hd->fp, "# %s info available, use -I to display\n",
            feat_ops[feat].name);

    return 0;
}

int perf_header__fprintf_info(struct perf_session *session, FILE *fp, bool full)
{
    struct header_print_data hd;
    struct perf_header *header = &session->header;
    int fd = perf_data__fd(session->data);
    struct stat st;
    int ret, bit;

    hd.fp = fp;
    hd.full = full;

    ret = fstat(fd, &st);
    if (ret == -1)
        return -1;

    fprintf(fp, "# captured on    : %s", ctime(&st.st_ctime));

    fprintf(fp, "# header version : %u\n", header->version);
    fprintf(fp, "# data offset    : %" PRIu64 "\n", header->data_offset);
    fprintf(fp, "# data size      : %" PRIu64 "\n", header->data_size);
    fprintf(fp, "# feat offset    : %" PRIu64 "\n", header->feat_offset);

    perf_header__process_sections(header, fd, &hd,
                      perf_file_section__fprintf_info);

    if (session->data->is_pipe)
        return 0;

    fprintf(fp, "# missing features: ");
    for_each_clear_bit(bit, header->adds_features, HEADER_LAST_FEATURE) {
        if (bit)
            fprintf(fp, "%s ", feat_ops[bit].name);
    }

    fprintf(fp, "\n");
    return 0;
}

static int do_write_feat(struct feat_fd *ff, int type,
             struct perf_file_section **p,
             struct perf_evlist *evlist)
{
    int err;
    int ret = 0;

    if (perf_header__has_feat(ff->ph, type)) {
        if (!feat_ops[type].write)
            return -1;

        if (WARN(ff->buf, "Error: calling %s in pipe-mode.\n", __func__))
            return -1;

        (*p)->offset = lseek(ff->fd, 0, SEEK_CUR);

        err = feat_ops[type].write(ff, evlist);
        if (err < 0) {
            pr_debug("failed to write feature %s\n", feat_ops[type].name);

            /* undo anything written */
            lseek(ff->fd, (*p)->offset, SEEK_SET);

            return -1;
        }
        (*p)->size = lseek(ff->fd, 0, SEEK_CUR) - (*p)->offset;
        (*p)++;
    }
    return ret;
}

static int perf_header__adds_write(struct perf_header *header,
                   struct perf_evlist *evlist, int fd)
{
    int nr_sections;
    struct feat_fd ff;
    struct perf_file_section *feat_sec, *p;
    int sec_size;
    u64 sec_start;
    int feat;
    int err;

    ff = (struct feat_fd){
        .fd  = fd,
        .ph = header,
    };

    nr_sections = bitmap_weight(header->adds_features, HEADER_FEAT_BITS);
    if (!nr_sections)
        return 0;

    feat_sec = p = calloc(nr_sections, sizeof(*feat_sec));
    if (feat_sec == NULL)
        return -ENOMEM;

    sec_size = sizeof(*feat_sec) * nr_sections;

    sec_start = header->feat_offset;
    lseek(fd, sec_start + sec_size, SEEK_SET);

    for_each_set_bit(feat, header->adds_features, HEADER_FEAT_BITS) {
        if (do_write_feat(&ff, feat, &p, evlist))
            perf_header__clear_feat(header, feat);
    }

    lseek(fd, sec_start, SEEK_SET);
    /*
     * may write more than needed due to dropped feature, but
     * this is okay, reader will skip the mising entries
     */
    err = do_write(&ff, feat_sec, sec_size);
    if (err < 0)
        pr_debug("failed to write feature section\n");
    free(feat_sec);
    return err;
}

int perf_header__write_pipe(int fd)
{
    struct perf_pipe_file_header f_header;
    struct feat_fd ff;
    int err;

    ff = (struct feat_fd){ .fd = fd };

    f_header = (struct perf_pipe_file_header){
        .magic     = PERF_MAGIC,
        .size      = sizeof(f_header),
    };

    err = do_write(&ff, &f_header, sizeof(f_header));
    if (err < 0) {
        pr_debug("failed to write perf pipe header\n");
        return err;
    }

    return 0;
}

int perf_session__write_header(struct perf_session *session,
                   struct perf_evlist *evlist,
                   int fd, bool at_exit)
{
    struct perf_file_header f_header;
    struct perf_file_attr   f_attr;
    struct perf_header *header = &session->header;
    struct perf_evsel *evsel;
    struct feat_fd ff;
    u64 attr_offset;
    int err;

    ff = (struct feat_fd){ .fd = fd};
    lseek(fd, sizeof(f_header), SEEK_SET);

    evlist__for_each_entry(session->evlist, evsel) {
        evsel->id_offset = lseek(fd, 0, SEEK_CUR);
        err = do_write(&ff, evsel->id, evsel->ids * sizeof(u64));
        if (err < 0) {
            pr_debug("failed to write perf header\n");
            return err;
        }
    }

    attr_offset = lseek(ff.fd, 0, SEEK_CUR);

    evlist__for_each_entry(evlist, evsel) {
        f_attr = (struct perf_file_attr){
            .attr = evsel->attr,
            .ids  = {
                .offset = evsel->id_offset,
                .size   = evsel->ids * sizeof(u64),
            }
        };
        err = do_write(&ff, &f_attr, sizeof(f_attr));
        if (err < 0) {
            pr_debug("failed to write perf header attribute\n");
            return err;
        }
    }

    if (!header->data_offset)
        header->data_offset = lseek(fd, 0, SEEK_CUR);
    header->feat_offset = header->data_offset + header->data_size;

    if (at_exit) {
        err = perf_header__adds_write(header, evlist, fd);
        if (err < 0)
            return err;
    }

    f_header = (struct perf_file_header){
        .magic     = PERF_MAGIC,
        .size      = sizeof(f_header),
        .attr_size = sizeof(f_attr),
        .attrs = {
            .offset = attr_offset,
            .size   = evlist->nr_entries * sizeof(f_attr),
        },
        .data = {
            .offset = header->data_offset,
            .size   = header->data_size,
        },
        /* event_types is ignored, store zeros */
    };

    memcpy(&f_header.adds_features, &header->adds_features, sizeof(header->adds_features));

    lseek(fd, 0, SEEK_SET);
    err = do_write(&ff, &f_header, sizeof(f_header));
    if (err < 0) {
        pr_debug("failed to write perf header\n");
        return err;
    }
    lseek(fd, header->data_offset + header->data_size, SEEK_SET);

    return 0;
}

static int perf_header__getbuffer64(struct perf_header *header,
                    int fd, void *buf, size_t size)
{
    if (readn(fd, buf, size) <= 0)
        return -1;

    if (header->needs_swap)
        mem_bswap_64(buf, size);

    return 0;
}

int perf_header__process_sections(struct perf_header *header, int fd,
                  void *data,
                  int (*process)(struct perf_file_section *section,
                         struct perf_header *ph,
                         int feat, int fd, void *data))
{
    struct perf_file_section *feat_sec, *sec;
    int nr_sections;
    int sec_size;
    int feat;
    int err;

    nr_sections = bitmap_weight(header->adds_features, HEADER_FEAT_BITS);
    if (!nr_sections)
        return 0;

    feat_sec = sec = calloc(nr_sections, sizeof(*feat_sec));
    if (!feat_sec)
        return -1;

    sec_size = sizeof(*feat_sec) * nr_sections;

    lseek(fd, header->feat_offset, SEEK_SET);

    err = perf_header__getbuffer64(header, fd, feat_sec, sec_size);
    if (err < 0)
        goto out_free;

    for_each_set_bit(feat, header->adds_features, HEADER_LAST_FEATURE) {
        err = process(sec++, header, feat, fd, data);
        if (err < 0)
            goto out_free;
    }
    err = 0;
out_free:
    free(feat_sec);
    return err;
}

static const int attr_file_abi_sizes[] = {
    [0] = PERF_ATTR_SIZE_VER0,
    [1] = PERF_ATTR_SIZE_VER1,
    [2] = PERF_ATTR_SIZE_VER2,
    [3] = PERF_ATTR_SIZE_VER3,
    [4] = PERF_ATTR_SIZE_VER4,
    0,
};

/*
 * In the legacy file format, the magic number is not used to encode endianness.
 * hdr_sz was used to encode endianness. But given that hdr_sz can vary based
 * on ABI revisions, we need to try all combinations for all endianness to
 * detect the endianness.
 */
static int try_all_file_abis(uint64_t hdr_sz, struct perf_header *ph)
{
    uint64_t ref_size, attr_size;
    int i;

    for (i = 0 ; attr_file_abi_sizes[i]; i++) {
        ref_size = attr_file_abi_sizes[i]
             + sizeof(struct perf_file_section);
        if (hdr_sz != ref_size) {
            attr_size = bswap_64(hdr_sz);
            if (attr_size != ref_size)
                continue;

            ph->needs_swap = true;
        }
        pr_debug("ABI%d perf.data file detected, need_swap=%d\n",
             i,
             ph->needs_swap);
        return 0;
    }
    /* could not determine endianness */
    return -1;
}

#define PERF_PIPE_HDR_VER0  16

static const size_t attr_pipe_abi_sizes[] = {
    [0] = PERF_PIPE_HDR_VER0,
    0,
};

/*
 * In the legacy pipe format, there is an implicit assumption that endiannesss
 * between host recording the samples, and host parsing the samples is the
 * same. This is not always the case given that the pipe output may always be
 * redirected into a file and analyzed on a different machine with possibly a
 * different endianness and perf_event ABI revsions in the perf tool itself.
 */
static int try_all_pipe_abis(uint64_t hdr_sz, struct perf_header *ph)
{
    u64 attr_size;
    int i;

    for (i = 0 ; attr_pipe_abi_sizes[i]; i++) {
        if (hdr_sz != attr_pipe_abi_sizes[i]) {
            attr_size = bswap_64(hdr_sz);
            if (attr_size != hdr_sz)
                continue;

            ph->needs_swap = true;
        }
        pr_debug("Pipe ABI%d perf.data file detected\n", i);
        return 0;
    }
    return -1;
}

bool is_perf_magic(u64 magic)
{
    if (!memcmp(&magic, __perf_magic1, sizeof(magic))
        || magic == __perf_magic2
        || magic == __perf_magic2_sw)
        return true;

    return false;
}

static int check_magic_endian(u64 magic, uint64_t hdr_sz,
                  bool is_pipe, struct perf_header *ph)
{
    int ret;

    /* check for legacy format */
    ret = memcmp(&magic, __perf_magic1, sizeof(magic));
    if (ret == 0) {
        ph->version = PERF_HEADER_VERSION_1;
        pr_debug("legacy perf.data format\n");
        if (is_pipe)
            return try_all_pipe_abis(hdr_sz, ph);

        return try_all_file_abis(hdr_sz, ph);
    }
    /*
     * the new magic number serves two purposes:
     * - unique number to identify actual perf.data files
     * - encode endianness of file
     */
    ph->version = PERF_HEADER_VERSION_2;

    /* check magic number with one endianness */
    if (magic == __perf_magic2)
        return 0;

    /* check magic number with opposite endianness */
    if (magic != __perf_magic2_sw)
        return -1;

    ph->needs_swap = true;

    return 0;
}

int perf_file_header__read(struct perf_file_header *header,
               struct perf_header *ph, int fd)
{
    ssize_t ret;

    lseek(fd, 0, SEEK_SET);

    ret = readn(fd, header, sizeof(*header));
    if (ret <= 0)
        return -1;

    if (check_magic_endian(header->magic,
                   header->attr_size, false, ph) < 0) {
        pr_debug("magic/endian check failed\n");
        return -1;
    }

    if (ph->needs_swap) {
        mem_bswap_64(header, offsetof(struct perf_file_header,
                 adds_features));
    }

    if (header->size != sizeof(*header)) {
        /* Support the previous format */
        if (header->size == offsetof(typeof(*header), adds_features))
            bitmap_zero(header->adds_features, HEADER_FEAT_BITS);
        else
            return -1;
    } else if (ph->needs_swap) {
        /*
         * feature bitmap is declared as an array of unsigned longs --
         * not good since its size can differ between the host that
         * generated the data file and the host analyzing the file.
         *
         * We need to handle endianness, but we don't know the size of
         * the unsigned long where the file was generated. Take a best
         * guess at determining it: try 64-bit swap first (ie., file
         * created on a 64-bit host), and check if the hostname feature
         * bit is set (this feature bit is forced on as of fbe96f2).
         * If the bit is not, undo the 64-bit swap and try a 32-bit
         * swap. If the hostname bit is still not set (e.g., older data
         * file), punt and fallback to the original behavior --
         * clearing all feature bits and setting buildid.
         */
        mem_bswap_64(&header->adds_features,
                BITS_TO_U64(HEADER_FEAT_BITS));

        if (!test_bit(HEADER_HOSTNAME, header->adds_features)) {
            /* unswap as u64 */
            mem_bswap_64(&header->adds_features,
                    BITS_TO_U64(HEADER_FEAT_BITS));

            /* unswap as u32 */
            mem_bswap_32(&header->adds_features,
                    BITS_TO_U32(HEADER_FEAT_BITS));
        }

        if (!test_bit(HEADER_HOSTNAME, header->adds_features)) {
            bitmap_zero(header->adds_features, HEADER_FEAT_BITS);
            set_bit(HEADER_BUILD_ID, header->adds_features);
        }
    }

    memcpy(&ph->adds_features, &header->adds_features,
           sizeof(ph->adds_features));

    ph->data_offset  = header->data.offset;
    ph->data_size    = header->data.size;
    ph->feat_offset  = header->data.offset + header->data.size;
    return 0;
}

static int perf_file_section__process(struct perf_file_section *section,
                      struct perf_header *ph,
                      int feat, int fd, void *data)
{
    struct feat_fd fdd = {
        .fd = fd,
        .ph = ph,
        .size   = section->size,
        .offset = section->offset,
    };

    if (lseek(fd, section->offset, SEEK_SET) == (off_t)-1) {
        pr_debug("Failed to lseek to %" PRIu64 " offset for feature "
              "%d, continuing...\n", section->offset, feat);
        return 0;
    }

    if (feat >= HEADER_LAST_FEATURE) {
        pr_debug("unknown feature %d, continuing...\n", feat);
        return 0;
    }

    if (!feat_ops[feat].process)
        return 0;

    return feat_ops[feat].process(&fdd, data);
}

static int perf_file_header__read_pipe(struct perf_pipe_file_header *header,
                       struct perf_header *ph, int fd,
                       bool repipe)
{
    struct feat_fd ff = {
        .fd = STDOUT_FILENO,
        .ph = ph,
    };
    ssize_t ret;

    ret = readn(fd, header, sizeof(*header));
    if (ret <= 0)
        return -1;

    if (check_magic_endian(header->magic, header->size, true, ph) < 0) {
        pr_debug("endian/magic failed\n");
        return -1;
    }

    if (ph->needs_swap)
        header->size = bswap_64(header->size);

    if (repipe && do_write(&ff, header, sizeof(*header)) < 0)
        return -1;

    return 0;
}

static int perf_header__read_pipe(struct perf_session *session)
{
    struct perf_header *header = &session->header;
    struct perf_pipe_file_header f_header;

    if (perf_file_header__read_pipe(&f_header, header,
                    perf_data__fd(session->data),
                    session->repipe) < 0) {
        pr_debug("incompatible file format\n");
        return -EINVAL;
    }

    return 0;
}

static int read_attr(int fd, struct perf_header *ph,
             struct perf_file_attr *f_attr)
{
    struct perf_event_attr *attr = &f_attr->attr;
    size_t sz, left;
    size_t our_sz = sizeof(f_attr->attr);
    ssize_t ret;

    memset(f_attr, 0, sizeof(*f_attr));

    /* read minimal guaranteed structure */
    ret = readn(fd, attr, PERF_ATTR_SIZE_VER0);
    if (ret <= 0) {
        pr_debug("cannot read %d bytes of header attr\n",
             PERF_ATTR_SIZE_VER0);
        return -1;
    }

    /* on file perf_event_attr size */
    sz = attr->size;

    if (ph->needs_swap)
        sz = bswap_32(sz);

    if (sz == 0) {
        /* assume ABI0 */
        sz =  PERF_ATTR_SIZE_VER0;
    } else if (sz > our_sz) {
        pr_debug("file uses a more recent and unsupported ABI"
             " (%zu bytes extra)\n", sz - our_sz);
        return -1;
    }
    /* what we have not yet read and that we know about */
    left = sz - PERF_ATTR_SIZE_VER0;
    if (left) {
        void *ptr = attr;
        ptr += PERF_ATTR_SIZE_VER0;

        ret = readn(fd, ptr, left);
    }
    /* read perf_file_section, ids are read in caller */
    ret = readn(fd, &f_attr->ids, sizeof(f_attr->ids));

    return ret <= 0 ? -1 : 0;
}

static int perf_evsel__prepare_tracepoint_event(struct perf_evsel *evsel,
                        struct pevent *pevent)
{
    struct event_format *event;
    char bf[128];

    /* already prepared */
    if (evsel->tp_format)
        return 0;

    if (pevent == NULL) {
        pr_debug("broken or missing trace data\n");
        return -1;
    }

    event = pevent_find_event(pevent, evsel->attr.config);
    if (event == NULL) {
        pr_debug("cannot find event format for %d\n", (int)evsel->attr.config);
        return -1;
    }

    if (!evsel->name) {
        snprintf(bf, sizeof(bf), "%s:%s", event->system, event->name);
        evsel->name = strdup(bf);
        if (evsel->name == NULL)
            return -1;
    }

    evsel->tp_format = event;
    return 0;
}

static int perf_evlist__prepare_tracepoint_events(struct perf_evlist *evlist,
                          struct pevent *pevent)
{
    struct perf_evsel *pos;

    evlist__for_each_entry(evlist, pos) {
        if (pos->attr.type == PERF_TYPE_TRACEPOINT &&
            perf_evsel__prepare_tracepoint_event(pos, pevent))
            return -1;
    }

    return 0;
}

int perf_session__read_header(struct perf_session *session)
{
    struct perf_data *data = session->data;
    struct perf_header *header = &session->header;
    struct perf_file_header f_header;
    struct perf_file_attr   f_attr;
    u64         f_id;
    int nr_attrs, nr_ids, i, j;
    int fd = perf_data__fd(data);

    session->evlist = perf_evlist__new();
    if (session->evlist == NULL)
        return -ENOMEM;

    session->evlist->env = &header->env;
    session->machines.host.env = &header->env;
    if (perf_data__is_pipe(data))
        return perf_header__read_pipe(session);

    if (perf_file_header__read(&f_header, header, fd) < 0)
        return -EINVAL;

    /*
     * Sanity check that perf.data was written cleanly; data size is
     * initialized to 0 and updated only if the on_exit function is run.
     * If data size is still 0 then the file contains only partial
     * information.  Just warn user and process it as much as it can.
     */
    if (f_header.data.size == 0) {
        pr_warning("WARNING: The %s file's data size field is 0 which is unexpected.\n"
               "Was the 'perf record' command properly terminated?\n",
               data->file.path);
    }

    nr_attrs = f_header.attrs.size / f_header.attr_size;
    lseek(fd, f_header.attrs.offset, SEEK_SET);

    for (i = 0; i < nr_attrs; i++) {
        struct perf_evsel *evsel;
        off_t tmp;

        if (read_attr(fd, header, &f_attr) < 0)
            goto out_errno;

        if (header->needs_swap) {
            f_attr.ids.size   = bswap_64(f_attr.ids.size);
            f_attr.ids.offset = bswap_64(f_attr.ids.offset);
            perf_event__attr_swap(&f_attr.attr);
        }

        tmp = lseek(fd, 0, SEEK_CUR);
        evsel = perf_evsel__new(&f_attr.attr);

        if (evsel == NULL)
            goto out_delete_evlist;

        evsel->needs_swap = header->needs_swap;
        /*
         * Do it before so that if perf_evsel__alloc_id fails, this
         * entry gets purged too at perf_evlist__delete().
         */
        perf_evlist__add(session->evlist, evsel);

        nr_ids = f_attr.ids.size / sizeof(u64);
        /*
         * We don't have the cpu and thread maps on the header, so
         * for allocating the perf_sample_id table we fake 1 cpu and
         * hattr->ids threads.
         */
        if (perf_evsel__alloc_id(evsel, 1, nr_ids))
            goto out_delete_evlist;

        lseek(fd, f_attr.ids.offset, SEEK_SET);

        for (j = 0; j < nr_ids; j++) {
            if (perf_header__getbuffer64(header, fd, &f_id, sizeof(f_id)))
                goto out_errno;

            perf_evlist__id_add(session->evlist, evsel, 0, j, f_id);
        }

        lseek(fd, tmp, SEEK_SET);
    }

    perf_header__process_sections(header, fd, &session->tevent,
                      perf_file_section__process);

    if (perf_evlist__prepare_tracepoint_events(session->evlist,
                           session->tevent.pevent))
        goto out_delete_evlist;

    return 0;
out_errno:
    return -errno;

out_delete_evlist:
    perf_evlist__delete(session->evlist);
    session->evlist = NULL;
    return -ENOMEM;
}

int perf_event__synthesize_attr(struct perf_tool *tool,
                struct perf_event_attr *attr, u32 ids, u64 *id,
                perf_event__handler_t process)
{
    union perf_event *ev;
    size_t size;
    int err;

    size = sizeof(struct perf_event_attr);
    size = PERF_ALIGN(size, sizeof(u64));
    size += sizeof(struct perf_event_header);
    size += ids * sizeof(u64);

    ev = malloc(size);

    if (ev == NULL)
        return -ENOMEM;

    ev->attr.attr = *attr;
    memcpy(ev->attr.id, id, ids * sizeof(u64));

    ev->attr.header.type = PERF_RECORD_HEADER_ATTR;
    ev->attr.header.size = (u16)size;

    if (ev->attr.header.size == size)
        err = process(tool, ev, NULL, NULL);
    else
        err = -E2BIG;

    free(ev);

    return err;
}

int perf_event__synthesize_features(struct perf_tool *tool,
                    struct perf_session *session,
                    struct perf_evlist *evlist,
                    perf_event__handler_t process)
{
    struct perf_header *header = &session->header;
    struct feat_fd ff;
    struct feature_event *fe;
    size_t sz, sz_hdr;
    int feat, ret;

    sz_hdr = sizeof(fe->header);
    sz = sizeof(union perf_event);
    /* get a nice alignment */
    sz = PERF_ALIGN(sz, page_size);

    memset(&ff, 0, sizeof(ff));

    ff.buf = malloc(sz);
    if (!ff.buf)
        return -ENOMEM;

    ff.size = sz - sz_hdr;

    for_each_set_bit(feat, header->adds_features, HEADER_FEAT_BITS) {
        if (!feat_ops[feat].synthesize) {
            pr_debug("No record header feature for header :%d\n", feat);
            continue;
        }

        ff.offset = sizeof(*fe);

        ret = feat_ops[feat].write(&ff, evlist);
        if (ret || ff.offset <= (ssize_t)sizeof(*fe)) {
            pr_debug("Error writing feature\n");
            continue;
        }
        /* ff.buf may have changed due to realloc in do_write() */
        fe = ff.buf;
        memset(fe, 0, sizeof(*fe));

        fe->feat_id = feat;
        fe->header.type = PERF_RECORD_HEADER_FEATURE;
        fe->header.size = ff.offset;

        ret = process(tool, ff.buf, NULL, NULL);
        if (ret) {
            free(ff.buf);
            return ret;
        }
    }

    /* Send HEADER_LAST_FEATURE mark. */
    fe = ff.buf;
    fe->feat_id     = HEADER_LAST_FEATURE;
    fe->header.type = PERF_RECORD_HEADER_FEATURE;
    fe->header.size = sizeof(*fe);

    ret = process(tool, ff.buf, NULL, NULL);

    free(ff.buf);
    return ret;
}

int perf_event__process_feature(struct perf_tool *tool,
                union perf_event *event,
                struct perf_session *session __maybe_unused)
{
    struct feat_fd ff = { .fd = 0 };
    struct feature_event *fe = (struct feature_event *)event;
    int type = fe->header.type;
    u64 feat = fe->feat_id;

    if (type < 0 || type >= PERF_RECORD_HEADER_MAX) {
        pr_warning("invalid record type %d in pipe-mode\n", type);
        return 0;
    }
    if (feat == HEADER_RESERVED || feat > HEADER_LAST_FEATURE) {
        pr_warning("invalid record type %d in pipe-mode\n", type);
        return -1;
    }

    if (!feat_ops[feat].process)
        return 0;

    ff.buf  = (void *)fe->data;
    ff.size = event->header.size - sizeof(event->header);
    ff.ph = &session->header;

    if (feat_ops[feat].process(&ff, NULL))
        return -1;

    if (!feat_ops[feat].print || !tool->show_feat_hdr)
        return 0;

    if (!feat_ops[feat].full_only ||
        tool->show_feat_hdr >= SHOW_FEAT_HEADER_FULL_INFO) {
        feat_ops[feat].print(&ff, stdout);
    } else {
        fprintf(stdout, "# %s info available, use -I to display\n",
            feat_ops[feat].name);
    }

    return 0;
}

static struct event_update_event *
event_update_event__new(size_t size, u64 type, u64 id)
{
    struct event_update_event *ev;

    size += sizeof(*ev);
    size  = PERF_ALIGN(size, sizeof(u64));

    ev = zalloc(size);
    if (ev) {
        ev->header.type = PERF_RECORD_EVENT_UPDATE;
        ev->header.size = (u16)size;
        ev->type = type;
        ev->id = id;
    }
    return ev;
}

int
perf_event__synthesize_event_update_unit(struct perf_tool *tool,
                     struct perf_evsel *evsel,
                     perf_event__handler_t process)
{
    struct event_update_event *ev;
    size_t size = strlen(evsel->unit);
    int err;

    ev = event_update_event__new(size + 1, PERF_EVENT_UPDATE__UNIT, evsel->id[0]);
    if (ev == NULL)
        return -ENOMEM;

    strncpy(ev->data, evsel->unit, size);
    err = process(tool, (union perf_event *)ev, NULL, NULL);
    free(ev);
    return err;
}

int
perf_event__synthesize_event_update_scale(struct perf_tool *tool,
                      struct perf_evsel *evsel,
                      perf_event__handler_t process)
{
    struct event_update_event *ev;
    struct event_update_event_scale *ev_data;
    int err;

    ev = event_update_event__new(sizeof(*ev_data), PERF_EVENT_UPDATE__SCALE, evsel->id[0]);
    if (ev == NULL)
        return -ENOMEM;

    ev_data = (struct event_update_event_scale *) ev->data;
    ev_data->scale = evsel->scale;
    err = process(tool, (union perf_event*) ev, NULL, NULL);
    free(ev);
    return err;
}

int
perf_event__synthesize_event_update_name(struct perf_tool *tool,
                     struct perf_evsel *evsel,
                     perf_event__handler_t process)
{
    struct event_update_event *ev;
    size_t len = strlen(evsel->name);
    int err;

    ev = event_update_event__new(len + 1, PERF_EVENT_UPDATE__NAME, evsel->id[0]);
    if (ev == NULL)
        return -ENOMEM;

    strncpy(ev->data, evsel->name, len);
    err = process(tool, (union perf_event*) ev, NULL, NULL);
    free(ev);
    return err;
}

int
perf_event__synthesize_event_update_cpus(struct perf_tool *tool,
                    struct perf_evsel *evsel,
                    perf_event__handler_t process)
{
    size_t size = sizeof(struct event_update_event);
    struct event_update_event *ev;
    int max, err;
    u16 type;

    if (!evsel->own_cpus)
        return 0;

    ev = cpu_map_data__alloc(evsel->own_cpus, &size, &type, &max);
    if (!ev)
        return -ENOMEM;

    ev->header.type = PERF_RECORD_EVENT_UPDATE;
    ev->header.size = (u16)size;
    ev->type = PERF_EVENT_UPDATE__CPUS;
    ev->id   = evsel->id[0];

    cpu_map_data__synthesize((struct cpu_map_data *) ev->data,
                 evsel->own_cpus,
                 type, max);

    err = process(tool, (union perf_event*) ev, NULL, NULL);
    free(ev);
    return err;
}

size_t perf_event__fprintf_event_update(union perf_event *event, FILE *fp)
{
    struct event_update_event *ev = &event->event_update;
    struct event_update_event_scale *ev_scale;
    struct event_update_event_cpus *ev_cpus;
    struct cpu_map *map;
    size_t ret;

    ret = fprintf(fp, "\n... id:    %" PRIu64 "\n", ev->id);

    switch (ev->type) {
    case PERF_EVENT_UPDATE__SCALE:
        ev_scale = (struct event_update_event_scale *) ev->data;
        ret += fprintf(fp, "... scale: %f\n", ev_scale->scale);
        break;
    case PERF_EVENT_UPDATE__UNIT:
        ret += fprintf(fp, "... unit:  %s\n", ev->data);
        break;
    case PERF_EVENT_UPDATE__NAME:
        ret += fprintf(fp, "... name:  %s\n", ev->data);
        break;
    case PERF_EVENT_UPDATE__CPUS:
        ev_cpus = (struct event_update_event_cpus *) ev->data;
        ret += fprintf(fp, "... ");

        map = cpu_map__new_data(&ev_cpus->cpus);
        if (map)
            ret += cpu_map__fprintf(map, fp);
        else
            ret += fprintf(fp, "failed to get cpus\n");
        break;
    default:
        ret += fprintf(fp, "... unknown type\n");
        break;
    }

    return ret;
}

int perf_event__synthesize_attrs(struct perf_tool *tool,
                   struct perf_session *session,
                   perf_event__handler_t process)
{
    struct perf_evsel *evsel;
    int err = 0;

    evlist__for_each_entry(session->evlist, evsel) {
        err = perf_event__synthesize_attr(tool, &evsel->attr, evsel->ids,
                          evsel->id, process);
        if (err) {
            pr_debug("failed to create perf header attribute\n");
            return err;
        }
    }

    return err;
}

static bool has_unit(struct perf_evsel *counter)
{
    return counter->unit && *counter->unit;
}

static bool has_scale(struct perf_evsel *counter)
{
    return counter->scale != 1;
}

int perf_event__synthesize_extra_attr(struct perf_tool *tool,
                      struct perf_evlist *evsel_list,
                      perf_event__handler_t process,
                      bool is_pipe)
{
    struct perf_evsel *counter;
    int err;

    /*
     * Synthesize other events stuff not carried within
     * attr event - unit, scale, name
     */
    evlist__for_each_entry(evsel_list, counter) {
        if (!counter->supported)
            continue;

        /*
         * Synthesize unit and scale only if it's defined.
         */
        if (has_unit(counter)) {
            err = perf_event__synthesize_event_update_unit(tool, counter, process);
            if (err < 0) {
                pr_err("Couldn't synthesize evsel unit.\n");
                return err;
            }
        }

        if (has_scale(counter)) {
            err = perf_event__synthesize_event_update_scale(tool, counter, process);
            if (err < 0) {
                pr_err("Couldn't synthesize evsel counter.\n");
                return err;
            }
        }

        if (counter->own_cpus) {
            err = perf_event__synthesize_event_update_cpus(tool, counter, process);
            if (err < 0) {
                pr_err("Couldn't synthesize evsel cpus.\n");
                return err;
            }
        }

        /*
         * Name is needed only for pipe output,
         * perf.data carries event names.
         */
        if (is_pipe) {
            err = perf_event__synthesize_event_update_name(tool, counter, process);
            if (err < 0) {
                pr_err("Couldn't synthesize evsel name.\n");
                return err;
            }
        }
    }
    return 0;
}

int perf_event__process_attr(struct perf_tool *tool __maybe_unused,
                 union perf_event *event,
                 struct perf_evlist **pevlist)
{
    u32 i, ids, n_ids;
    struct perf_evsel *evsel;
    struct perf_evlist *evlist = *pevlist;

    if (evlist == NULL) {
        *pevlist = evlist = perf_evlist__new();
        if (evlist == NULL)
            return -ENOMEM;
    }

    evsel = perf_evsel__new(&event->attr.attr);
    if (evsel == NULL)
        return -ENOMEM;

    perf_evlist__add(evlist, evsel);

    ids = event->header.size;
    ids -= (void *)&event->attr.id - (void *)event;
    n_ids = ids / sizeof(u64);
    /*
     * We don't have the cpu and thread maps on the header, so
     * for allocating the perf_sample_id table we fake 1 cpu and
     * hattr->ids threads.
     */
    if (perf_evsel__alloc_id(evsel, 1, n_ids))
        return -ENOMEM;

    for (i = 0; i < n_ids; i++) {
        perf_evlist__id_add(evlist, evsel, 0, i, event->attr.id[i]);
    }

    return 0;
}

int perf_event__process_event_update(struct perf_tool *tool __maybe_unused,
                     union perf_event *event,
                     struct perf_evlist **pevlist)
{
    struct event_update_event *ev = &event->event_update;
    struct event_update_event_scale *ev_scale;
    struct event_update_event_cpus *ev_cpus;
    struct perf_evlist *evlist;
    struct perf_evsel *evsel;
    struct cpu_map *map;

    if (!pevlist || *pevlist == NULL)
        return -EINVAL;

    evlist = *pevlist;

    evsel = perf_evlist__id2evsel(evlist, ev->id);
    if (evsel == NULL)
        return -EINVAL;

    switch (ev->type) {
    case PERF_EVENT_UPDATE__UNIT:
        evsel->unit = strdup(ev->data);
        break;
    case PERF_EVENT_UPDATE__NAME:
        evsel->name = strdup(ev->data);
        break;
    case PERF_EVENT_UPDATE__SCALE:
        ev_scale = (struct event_update_event_scale *) ev->data;
        evsel->scale = ev_scale->scale;
        break;
    case PERF_EVENT_UPDATE__CPUS:
        ev_cpus = (struct event_update_event_cpus *) ev->data;

        map = cpu_map__new_data(&ev_cpus->cpus);
        if (map)
            evsel->own_cpus = map;
        else
            pr_err("failed to get event_update cpus\n");
    default:
        break;
    }

    return 0;
}

int perf_event__synthesize_tracing_data(struct perf_tool *tool, int fd,
                    struct perf_evlist *evlist,
                    perf_event__handler_t process)
{
    union perf_event ev;
    struct tracing_data *tdata;
    ssize_t size = 0, aligned_size = 0, padding;
    struct feat_fd ff;
    int err __maybe_unused = 0;

    /*
     * We are going to store the size of the data followed
     * by the data contents. Since the fd descriptor is a pipe,
     * we cannot seek back to store the size of the data once
     * we know it. Instead we:
     *
     * - write the tracing data to the temp file
     * - get/write the data size to pipe
     * - write the tracing data from the temp file
     *   to the pipe
     */
    tdata = tracing_data_get(&evlist->entries, fd, true);
    if (!tdata)
        return -1;

    memset(&ev, 0, sizeof(ev));

    ev.tracing_data.header.type = PERF_RECORD_HEADER_TRACING_DATA;
    size = tdata->size;
    aligned_size = PERF_ALIGN(size, sizeof(u64));
    padding = aligned_size - size;
    ev.tracing_data.header.size = sizeof(ev.tracing_data);
    ev.tracing_data.size = aligned_size;

    process(tool, &ev, NULL, NULL);

    /*
     * The put function will copy all the tracing data
     * stored in temp file to the pipe.
     */
    tracing_data_put(tdata);

    ff = (struct feat_fd){ .fd = fd };
    if (write_padded(&ff, NULL, 0, padding))
        return -1;

    return aligned_size;
}

int perf_event__process_tracing_data(struct perf_tool *tool __maybe_unused,
                     union perf_event *event,
                     struct perf_session *session)
{
    ssize_t size_read, padding, size = event->tracing_data.size;
    int fd = perf_data__fd(session->data);
    off_t offset = lseek(fd, 0, SEEK_CUR);
    char buf[BUFSIZ];

    /* setup for reading amidst mmap */
    lseek(fd, offset + sizeof(struct tracing_data_event),
          SEEK_SET);

    size_read = trace_report(fd, &session->tevent,
                 session->repipe);
    padding = PERF_ALIGN(size_read, sizeof(u64)) - size_read;

    if (readn(fd, buf, padding) < 0) {
        pr_err("%s: reading input file", __func__);
        return -1;
    }
    if (session->repipe) {
        int retw = write(STDOUT_FILENO, buf, padding);
        if (retw <= 0 || retw != padding) {
            pr_err("%s: repiping tracing data padding", __func__);
            return -1;
        }
    }

    if (size_read + padding != size) {
        pr_err("%s: tracing data size mismatch", __func__);
        return -1;
    }

    perf_evlist__prepare_tracepoint_events(session->evlist,
                           session->tevent.pevent);

    return size_read + padding;
}

int perf_event__synthesize_build_id(struct perf_tool *tool,
                    struct dso *pos, u16 misc,
                    perf_event__handler_t process,
                    struct machine *machine)
{
    union perf_event ev;
    size_t len;
    int err = 0;

    if (!pos->hit)
        return err;

    memset(&ev, 0, sizeof(ev));

    len = pos->long_name_len + 1;
    len = PERF_ALIGN(len, NAME_ALIGN);
    memcpy(&ev.build_id.build_id, pos->build_id, sizeof(pos->build_id));
    ev.build_id.header.type = PERF_RECORD_HEADER_BUILD_ID;
    ev.build_id.header.misc = misc;
    ev.build_id.pid = machine->pid;
    ev.build_id.header.size = sizeof(ev.build_id) + len;
    memcpy(&ev.build_id.filename, pos->long_name, pos->long_name_len);

    err = process(tool, &ev, NULL, machine);

    return err;
}

int perf_event__process_build_id(struct perf_tool *tool __maybe_unused,
                 union perf_event *event,
                 struct perf_session *session)
{
    __event_process_build_id(&event->build_id,
                 event->build_id.filename,
                 session);
    return 0;
}