// SPDX-License-Identifier: GPL-2.0-only 

#include "util/debug.h"
#include "util/dso.h"
#include "util/event.h"
#include "util/evlist.h"
#include "util/machine.h"
#include "util/map.h"
#include "util/map_symbol.h"
#include "util/branch.h"
#include "util/memswap.h"
#include "util/namespaces.h"
#include "util/session.h"
#include "util/stat.h"
#include "util/symbol.h"
#include "util/synthetic-events.h"
#include "util/target.h"
#include "util/time-utils.h"
#include "util/cgroup.h"
#include <linux/bitops.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/zalloc.h>
#include <linux/perf_event.h>
#include <asm/bug.h>
#include <perf/evsel.h>
#include <internal/cpumap.h>
#include <perf/cpumap.h>
#include <internal/lib.h> // page_size
#include <internal/threadmap.h>
#include <perf/threadmap.h>
#include <symbol/kallsyms.h>
#include <dirent.h>
#include <errno.h>
#include <inttypes.h>
#include <stdio.h>
#include <string.h>
#include <uapi/linux/mman.h> /* To get things like MAP_HUGETLB even on older libc headers */
#include <api/fs/fs.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

#define DEFAULT_PROC_MAP_PARSE_TIMEOUT 500

unsigned int proc_map_timeout = DEFAULT_PROC_MAP_PARSE_TIMEOUT;

int perf_tool__process_synth_event(struct perf_tool *tool,
                                   union perf_event *event,
                                   struct machine *machine,
                                   perf_event__handler_t process)
{
        struct perf_sample synth_sample = {
                .pid       = -1,
                .tid       = -1,
                .time      = -1,
                .stream_id = -1,
                .cpu       = -1,
                .period    = 1,
                .cpumode   = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK,
        };

        return process(tool, event, &synth_sample, machine);
};

/*
 * Assumes that the first 4095 bytes of /proc/pid/stat contains
 * the comm, tgid and ppid.
 */
static int perf_event__get_comm_ids(pid_t pid, char *comm, size_t len,
                                    pid_t *tgid, pid_t *ppid)
{
        char filename[PATH_MAX];
        char bf[4096];
        int fd;
        size_t size = 0;
        ssize_t n;
        char *name, *tgids, *ppids;

        *tgid = -1;
        *ppid = -1;

        snprintf(filename, sizeof(filename), "/proc/%d/status", pid);

        fd = open(filename, O_RDONLY);
        if (fd < 0) {
                pr_debug("couldn't open %s\n", filename);
                return -1;
        }

        n = read(fd, bf, sizeof(bf) - 1);
        close(fd);
        if (n <= 0) {
                pr_warning("Couldn't get COMM, tigd and ppid for pid %d\n",
                           pid);
                return -1;
        }
        bf[n] = '\0';

        name = strstr(bf, "Name:");
        tgids = strstr(bf, "Tgid:");
        ppids = strstr(bf, "PPid:");

        if (name) {
                char *nl;

                name = skip_spaces(name + 5);  /* strlen("Name:") */
                nl = strchr(name, '\n');
                if (nl)
                        *nl = '\0';

                size = strlen(name);
                if (size >= len)
                        size = len - 1;
                memcpy(comm, name, size);
                comm[size] = '\0';
        } else {
                pr_debug("Name: string not found for pid %d\n", pid);
        }

        if (tgids) {
                tgids += 5;  /* strlen("Tgid:") */
                *tgid = atoi(tgids);
        } else {
                pr_debug("Tgid: string not found for pid %d\n", pid);
        }

        if (ppids) {
                ppids += 5;  /* strlen("PPid:") */
                *ppid = atoi(ppids);
        } else {
                pr_debug("PPid: string not found for pid %d\n", pid);
        }

        return 0;
}

static int perf_event__prepare_comm(union perf_event *event, pid_t pid,
                                    struct machine *machine,
                                    pid_t *tgid, pid_t *ppid)
{
        size_t size;

        *ppid = -1;

        memset(&event->comm, 0, sizeof(event->comm));

        if (machine__is_host(machine)) {
                if (perf_event__get_comm_ids(pid, event->comm.comm,
                                             sizeof(event->comm.comm),
                                             tgid, ppid) != 0) {
                        return -1;
                }
        } else {
                *tgid = machine->pid;
        }

        if (*tgid < 0)
                return -1;

        event->comm.pid = *tgid;
        event->comm.header.type = PERF_RECORD_COMM;

        size = strlen(event->comm.comm) + 1;
        size = PERF_ALIGN(size, sizeof(u64));
        memset(event->comm.comm + size, 0, machine->id_hdr_size);
        event->comm.header.size = (sizeof(event->comm) -
                                (sizeof(event->comm.comm) - size) +
                                machine->id_hdr_size);
        event->comm.tid = pid;

        return 0;
}

pid_t perf_event__synthesize_comm(struct perf_tool *tool,
                                         union perf_event *event, pid_t pid,
                                         perf_event__handler_t process,
                                         struct machine *machine)
{
        pid_t tgid, ppid;

        if (perf_event__prepare_comm(event, pid, machine, &tgid, &ppid) != 0)
                return -1;

        if (perf_tool__process_synth_event(tool, event, machine, process) != 0)
                return -1;

        return tgid;
}

static void perf_event__get_ns_link_info(pid_t pid, const char *ns,
                                         struct perf_ns_link_info *ns_link_info)
{
        struct stat64 st;
        char proc_ns[128];

        sprintf(proc_ns, "/proc/%u/ns/%s", pid, ns);
        if (stat64(proc_ns, &st) == 0) {
                ns_link_info->dev = st.st_dev;
                ns_link_info->ino = st.st_ino;
        }
}

int perf_event__synthesize_namespaces(struct perf_tool *tool,
                                      union perf_event *event,
                                      pid_t pid, pid_t tgid,
                                      perf_event__handler_t process,
                                      struct machine *machine)
{
        u32 idx;
        struct perf_ns_link_info *ns_link_info;

        if (!tool || !tool->namespace_events)
                return 0;

        memset(&event->namespaces, 0, (sizeof(event->namespaces) +
               (NR_NAMESPACES * sizeof(struct perf_ns_link_info)) +
               machine->id_hdr_size));

        event->namespaces.pid = tgid;
        event->namespaces.tid = pid;

        event->namespaces.nr_namespaces = NR_NAMESPACES;

        ns_link_info = event->namespaces.link_info;

        for (idx = 0; idx < event->namespaces.nr_namespaces; idx++)
                perf_event__get_ns_link_info(pid, perf_ns__name(idx),
                                             &ns_link_info[idx]);

        event->namespaces.header.type = PERF_RECORD_NAMESPACES;

        event->namespaces.header.size = (sizeof(event->namespaces) +
                        (NR_NAMESPACES * sizeof(struct perf_ns_link_info)) +
                        machine->id_hdr_size);

        if (perf_tool__process_synth_event(tool, event, machine, process) != 0)
                return -1;

        return 0;
}

static int perf_event__synthesize_fork(struct perf_tool *tool,
                                       union perf_event *event,
                                       pid_t pid, pid_t tgid, pid_t ppid,
                                       perf_event__handler_t process,
                                       struct machine *machine)
{
        memset(&event->fork, 0, sizeof(event->fork) + machine->id_hdr_size);

        /*
         * for main thread set parent to ppid from status file. For other
         * threads set parent pid to main thread. ie., assume main thread
         * spawns all threads in a process
        */
        if (tgid == pid) {
                event->fork.ppid = ppid;
                event->fork.ptid = ppid;
        } else {
                event->fork.ppid = tgid;
                event->fork.ptid = tgid;
        }
        event->fork.pid  = tgid;
        event->fork.tid  = pid;
        event->fork.header.type = PERF_RECORD_FORK;
        event->fork.header.misc = PERF_RECORD_MISC_FORK_EXEC;

        event->fork.header.size = (sizeof(event->fork) + machine->id_hdr_size);

        if (perf_tool__process_synth_event(tool, event, machine, process) != 0)
                return -1;

        return 0;
}

int perf_event__synthesize_mmap_events(struct perf_tool *tool,
                                       union perf_event *event,
                                       pid_t pid, pid_t tgid,
                                       perf_event__handler_t process,
                                       struct machine *machine,
                                       bool mmap_data)
{
        char filename[PATH_MAX];
        FILE *fp;
        unsigned long long t;
        bool truncation = false;
        unsigned long long timeout = proc_map_timeout * 1000000ULL;
        int rc = 0;
        const char *hugetlbfs_mnt = hugetlbfs__mountpoint();
        int hugetlbfs_mnt_len = hugetlbfs_mnt ? strlen(hugetlbfs_mnt) : 0;

        if (machine__is_default_guest(machine))
                return 0;

        snprintf(filename, sizeof(filename), "%s/proc/%d/task/%d/maps",
                 machine->root_dir, pid, pid);

        fp = fopen(filename, "r");
        if (fp == NULL) {
                /*
                 * We raced with a task exiting - just return:
                 */
                pr_debug("couldn't open %s\n", filename);
                return -1;
        }

        event->header.type = PERF_RECORD_MMAP2;
        t = rdclock();

        while (1) {
                char bf[BUFSIZ];
                char prot[5];
                char execname[PATH_MAX];
                char anonstr[] = "//anon";
                unsigned int ino;
                size_t size;
                ssize_t n;

                if (fgets(bf, sizeof(bf), fp) == NULL)
                        break;

                if ((rdclock() - t) > timeout) {
                        pr_warning("Reading %s time out. "
                                   "You may want to increase "
                                   "the time limit by --proc-map-timeout\n",
                                   filename);
                        truncation = true;
                        goto out;
                }

                /* ensure null termination since stack will be reused. */
                strcpy(execname, "");

                /* 00400000-0040c000 r-xp 00000000 fd:01 41038  /bin/cat */
                n = sscanf(bf, "%"PRI_lx64"-%"PRI_lx64" %s %"PRI_lx64" %x:%x %u %[^\n]\n",
                       &event->mmap2.start, &event->mmap2.len, prot,
                       &event->mmap2.pgoff, &event->mmap2.maj,
                       &event->mmap2.min,
                       &ino, execname);

                /*
                 * Anon maps don't have the execname.
                 */
                if (n < 7)
                        continue;

                event->mmap2.ino = (u64)ino;
                event->mmap2.ino_generation = 0;

                /*
                 * Just like the kernel, see __perf_event_mmap in kernel/perf_event.c
                 */
                if (machine__is_host(machine))
                        event->header.misc = PERF_RECORD_MISC_USER;
                else
                        event->header.misc = PERF_RECORD_MISC_GUEST_USER;

                /* map protection and flags bits */
                event->mmap2.prot = 0;
                event->mmap2.flags = 0;
                if (prot[0] == 'r')
                        event->mmap2.prot |= PROT_READ;
                if (prot[1] == 'w')
                        event->mmap2.prot |= PROT_WRITE;
                if (prot[2] == 'x')
                        event->mmap2.prot |= PROT_EXEC;

                if (prot[3] == 's')
                        event->mmap2.flags |= MAP_SHARED;
                else
                        event->mmap2.flags |= MAP_PRIVATE;

                if (prot[2] != 'x') {
                        if (!mmap_data || prot[0] != 'r')
                                continue;

                        event->header.misc |= PERF_RECORD_MISC_MMAP_DATA;
                }

out:
                if (truncation)
                        event->header.misc |= PERF_RECORD_MISC_PROC_MAP_PARSE_TIMEOUT;

                if (!strcmp(execname, ""))
                        strcpy(execname, anonstr);

                if (hugetlbfs_mnt_len &&
                    !strncmp(execname, hugetlbfs_mnt, hugetlbfs_mnt_len)) {
                        strcpy(execname, anonstr);
                        event->mmap2.flags |= MAP_HUGETLB;
                }

                size = strlen(execname) + 1;
                memcpy(event->mmap2.filename, execname, size);
                size = PERF_ALIGN(size, sizeof(u64));
                event->mmap2.len -= event->mmap.start;
                event->mmap2.header.size = (sizeof(event->mmap2) -
                                        (sizeof(event->mmap2.filename) - size));
                memset(event->mmap2.filename + size, 0, machine->id_hdr_size);
                event->mmap2.header.size += machine->id_hdr_size;
                event->mmap2.pid = tgid;
                event->mmap2.tid = pid;

                if (perf_tool__process_synth_event(tool, event, machine, process) != 0) {
                        rc = -1;
                        break;
                }

                if (truncation)
                        break;
        }

        fclose(fp);
        return rc;
}

#ifdef HAVE_FILE_HANDLE
static int perf_event__synthesize_cgroup(struct perf_tool *tool,
                                         union perf_event *event,
                                         char *path, size_t mount_len,
                                         perf_event__handler_t process,
                                         struct machine *machine)
{
        size_t event_size = sizeof(event->cgroup) - sizeof(event->cgroup.path);
        size_t path_len = strlen(path) - mount_len + 1;
        struct {
                struct file_handle fh;
                uint64_t cgroup_id;
        } handle;
        int mount_id;

        while (path_len % sizeof(u64))
                path[mount_len + path_len++] = '\0';

        memset(&event->cgroup, 0, event_size);

        event->cgroup.header.type = PERF_RECORD_CGROUP;
        event->cgroup.header.size = event_size + path_len + machine->id_hdr_size;

        handle.fh.handle_bytes = sizeof(handle.cgroup_id);
        if (name_to_handle_at(AT_FDCWD, path, &handle.fh, &mount_id, 0) < 0) {
                pr_debug("stat failed: %s\n", path);
                return -1;
        }

        event->cgroup.id = handle.cgroup_id;
        strncpy(event->cgroup.path, path + mount_len, path_len);
        memset(event->cgroup.path + path_len, 0, machine->id_hdr_size);

        if (perf_tool__process_synth_event(tool, event, machine, process) < 0) {
                pr_debug("process synth event failed\n");
                return -1;
        }

        return 0;
}

static int perf_event__walk_cgroup_tree(struct perf_tool *tool,
                                        union perf_event *event,
                                        char *path, size_t mount_len,
                                        perf_event__handler_t process,
                                        struct machine *machine)
{
        size_t pos = strlen(path);
        DIR *d;
        struct dirent *dent;
        int ret = 0;

        if (perf_event__synthesize_cgroup(tool, event, path, mount_len,
                                          process, machine) < 0)
                return -1;

        d = opendir(path);
        if (d == NULL) {
                pr_debug("failed to open directory: %s\n", path);
                return -1;
        }

        while ((dent = readdir(d)) != NULL) {
                if (dent->d_type != DT_DIR)
                        continue;
                if (!strcmp(dent->d_name, ".") ||
                    !strcmp(dent->d_name, ".."))
                        continue;

                /* any sane path should be less than PATH_MAX */
                if (strlen(path) + strlen(dent->d_name) + 1 >= PATH_MAX)
                        continue;

                if (path[pos - 1] != '/')
                        strcat(path, "/");
                strcat(path, dent->d_name);

                ret = perf_event__walk_cgroup_tree(tool, event, path,
                                                   mount_len, process, machine);
                if (ret < 0)
                        break;

                path[pos] = '\0';
        }

        closedir(d);
        return ret;
}

int perf_event__synthesize_cgroups(struct perf_tool *tool,
                                   perf_event__handler_t process,
                                   struct machine *machine)
{
        union perf_event event;
        char cgrp_root[PATH_MAX];
        size_t mount_len;  /* length of mount point in the path */

        if (cgroupfs_find_mountpoint(cgrp_root, PATH_MAX, "perf_event") < 0) {
                pr_debug("cannot find cgroup mount point\n");
                return -1;
        }

        mount_len = strlen(cgrp_root);
        /* make sure the path starts with a slash (after mount point) */
        strcat(cgrp_root, "/");

        if (perf_event__walk_cgroup_tree(tool, &event, cgrp_root, mount_len,
                                         process, machine) < 0)
                return -1;

        return 0;
}
#else
int perf_event__synthesize_cgroups(struct perf_tool *tool __maybe_unused,
                                   perf_event__handler_t process __maybe_unused,
                                   struct machine *machine __maybe_unused)
{
        return -1;
}
#endif

int perf_event__synthesize_modules(struct perf_tool *tool, perf_event__handler_t process,
                                   struct machine *machine)
{
        int rc = 0;
        struct map *pos;
        struct maps *maps = machine__kernel_maps(machine);
        union perf_event *event = zalloc((sizeof(event->mmap) +
                                          machine->id_hdr_size));
        if (event == NULL) {
                pr_debug("Not enough memory synthesizing mmap event "
                         "for kernel modules\n");
                return -1;
        }

        event->header.type = PERF_RECORD_MMAP;

        /*
         * kernel uses 0 for user space maps, see kernel/perf_event.c
         * __perf_event_mmap
         */
        if (machine__is_host(machine))
                event->header.misc = PERF_RECORD_MISC_KERNEL;
        else
                event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;

        maps__for_each_entry(maps, pos) {
                size_t size;

                if (!__map__is_kmodule(pos))
                        continue;

                size = PERF_ALIGN(pos->dso->long_name_len + 1, sizeof(u64));
                event->mmap.header.type = PERF_RECORD_MMAP;
                event->mmap.header.size = (sizeof(event->mmap) -
                                        (sizeof(event->mmap.filename) - size));
                memset(event->mmap.filename + size, 0, machine->id_hdr_size);
                event->mmap.header.size += machine->id_hdr_size;
                event->mmap.start = pos->start;
                event->mmap.len   = pos->end - pos->start;
                event->mmap.pid   = machine->pid;

                memcpy(event->mmap.filename, pos->dso->long_name,
                       pos->dso->long_name_len + 1);
                if (perf_tool__process_synth_event(tool, event, machine, process) != 0) {
                        rc = -1;
                        break;
                }
        }

        free(event);
        return rc;
}

static int __event__synthesize_thread(union perf_event *comm_event,
                                      union perf_event *mmap_event,
                                      union perf_event *fork_event,
                                      union perf_event *namespaces_event,
                                      pid_t pid, int full, perf_event__handler_t process,
                                      struct perf_tool *tool, struct machine *machine, bool mmap_data)
{
        char filename[PATH_MAX];
        DIR *tasks;
        struct dirent *dirent;
        pid_t tgid, ppid;
        int rc = 0;

        /* special case: only send one comm event using passed in pid */
        if (!full) {
                tgid = perf_event__synthesize_comm(tool, comm_event, pid,
                                                   process, machine);

                if (tgid == -1)
                        return -1;

                if (perf_event__synthesize_namespaces(tool, namespaces_event, pid,
                                                      tgid, process, machine) < 0)
                        return -1;

                /*
                 * send mmap only for thread group leader
                 * see thread__init_maps()
                 */
                if (pid == tgid &&
                    perf_event__synthesize_mmap_events(tool, mmap_event, pid, tgid,
                                                       process, machine, mmap_data))
                        return -1;

                return 0;
        }

        if (machine__is_default_guest(machine))
                return 0;

        snprintf(filename, sizeof(filename), "%s/proc/%d/task",
                 machine->root_dir, pid);

        tasks = opendir(filename);
        if (tasks == NULL) {
                pr_debug("couldn't open %s\n", filename);
                return 0;
        }

        while ((dirent = readdir(tasks)) != NULL) {
                char *end;
                pid_t _pid;

                _pid = strtol(dirent->d_name, &end, 10);
                if (*end)
                        continue;

                rc = -1;
                if (perf_event__prepare_comm(comm_event, _pid, machine,
                                             &tgid, &ppid) != 0)
                        break;

                if (perf_event__synthesize_fork(tool, fork_event, _pid, tgid,
                                                ppid, process, machine) < 0)
                        break;

                if (perf_event__synthesize_namespaces(tool, namespaces_event, _pid,
                                                      tgid, process, machine) < 0)
                        break;

                /*
                 * Send the prepared comm event
                 */
                if (perf_tool__process_synth_event(tool, comm_event, machine, process) != 0)
                        break;

                rc = 0;
                if (_pid == pid) {
                        /* process the parent's maps too */
                        rc = perf_event__synthesize_mmap_events(tool, mmap_event, pid, tgid,
                                                process, machine, mmap_data);
                        if (rc)
                                break;
                }
        }

        closedir(tasks);
        return rc;
}

int perf_event__synthesize_thread_map(struct perf_tool *tool,
                                      struct perf_thread_map *threads,
                                      perf_event__handler_t process,
                                      struct machine *machine,
                                      bool mmap_data)
{
        union perf_event *comm_event, *mmap_event, *fork_event;
        union perf_event *namespaces_event;
        int err = -1, thread, j;

        comm_event = malloc(sizeof(comm_event->comm) + machine->id_hdr_size);
        if (comm_event == NULL)
                goto out;

        mmap_event = malloc(sizeof(mmap_event->mmap2) + machine->id_hdr_size);
        if (mmap_event == NULL)
                goto out_free_comm;

        fork_event = malloc(sizeof(fork_event->fork) + machine->id_hdr_size);
        if (fork_event == NULL)
                goto out_free_mmap;

        namespaces_event = malloc(sizeof(namespaces_event->namespaces) +
                                  (NR_NAMESPACES * sizeof(struct perf_ns_link_info)) +
                                  machine->id_hdr_size);
        if (namespaces_event == NULL)
                goto out_free_fork;

        err = 0;
        for (thread = 0; thread < threads->nr; ++thread) {
                if (__event__synthesize_thread(comm_event, mmap_event,
                                               fork_event, namespaces_event,
                                               perf_thread_map__pid(threads, thread), 0,
                                               process, tool, machine,
                                               mmap_data)) {
                        err = -1;
                        break;
                }

                /*
                 * comm.pid is set to thread group id by
                 * perf_event__synthesize_comm
                 */
                if ((int) comm_event->comm.pid != perf_thread_map__pid(threads, thread)) {
                        bool need_leader = true;

                        /* is thread group leader in thread_map? */
                        for (j = 0; j < threads->nr; ++j) {
                                if ((int) comm_event->comm.pid == perf_thread_map__pid(threads, j)) {
                                        need_leader = false;
                                        break;
                                }
                        }

                        /* if not, generate events for it */
                        if (need_leader &&
                            __event__synthesize_thread(comm_event, mmap_event,
                                                       fork_event, namespaces_event,
                                                       comm_event->comm.pid, 0,
                                                       process, tool, machine,
                                                       mmap_data)) {
                                err = -1;
                                break;
                        }
                }
        }
        free(namespaces_event);
out_free_fork:
        free(fork_event);
out_free_mmap:
        free(mmap_event);
out_free_comm:
        free(comm_event);
out:
        return err;
}

static int __perf_event__synthesize_threads(struct perf_tool *tool,
                                            perf_event__handler_t process,
                                            struct machine *machine,
                                            bool mmap_data,
                                            struct dirent **dirent,
                                            int start,
                                            int num)
{
        union perf_event *comm_event, *mmap_event, *fork_event;
        union perf_event *namespaces_event;
        int err = -1;
        char *end;
        pid_t pid;
        int i;

        comm_event = malloc(sizeof(comm_event->comm) + machine->id_hdr_size);
        if (comm_event == NULL)
                goto out;

        mmap_event = malloc(sizeof(mmap_event->mmap2) + machine->id_hdr_size);
        if (mmap_event == NULL)
                goto out_free_comm;

        fork_event = malloc(sizeof(fork_event->fork) + machine->id_hdr_size);
        if (fork_event == NULL)
                goto out_free_mmap;

        namespaces_event = malloc(sizeof(namespaces_event->namespaces) +
                                  (NR_NAMESPACES * sizeof(struct perf_ns_link_info)) +
                                  machine->id_hdr_size);
        if (namespaces_event == NULL)
                goto out_free_fork;

        for (i = start; i < start + num; i++) {
                if (!isdigit(dirent[i]->d_name[0]))
                        continue;

                pid = (pid_t)strtol(dirent[i]->d_name, &end, 10);
                /* only interested in proper numerical dirents */
                if (*end)
                        continue;
                /*
                 * We may race with exiting thread, so don't stop just because
                 * one thread couldn't be synthesized.
                 */
                __event__synthesize_thread(comm_event, mmap_event, fork_event,
                                           namespaces_event, pid, 1, process,
                                           tool, machine, mmap_data);
        }
        err = 0;

        free(namespaces_event);
out_free_fork:
        free(fork_event);
out_free_mmap:
        free(mmap_event);
out_free_comm:
        free(comm_event);
out:
        return err;
}

struct synthesize_threads_arg {
        struct perf_tool *tool;
        perf_event__handler_t process;
        struct machine *machine;
        bool mmap_data;
        struct dirent **dirent;
        int num;
        int start;
};

static void *synthesize_threads_worker(void *arg)
{
        struct synthesize_threads_arg *args = arg;

        __perf_event__synthesize_threads(args->tool, args->process,
                                         args->machine, args->mmap_data,
                                         args->dirent,
                                         args->start, args->num);
        return NULL;
}

int perf_event__synthesize_threads(struct perf_tool *tool,
                                   perf_event__handler_t process,
                                   struct machine *machine,
                                   bool mmap_data,
                                   unsigned int nr_threads_synthesize)
{
        struct synthesize_threads_arg *args = NULL;
        pthread_t *synthesize_threads = NULL;
        char proc_path[PATH_MAX];
        struct dirent **dirent;
        int num_per_thread;
        int m, n, i, j;
        int thread_nr;
        int base = 0;
        int err = -1;


        if (machine__is_default_guest(machine))
                return 0;

        snprintf(proc_path, sizeof(proc_path), "%s/proc", machine->root_dir);
        n = scandir(proc_path, &dirent, 0, alphasort);
        if (n < 0)
                return err;

        if (nr_threads_synthesize == UINT_MAX)
                thread_nr = sysconf(_SC_NPROCESSORS_ONLN);
        else
                thread_nr = nr_threads_synthesize;

        if (thread_nr <= 1) {
                err = __perf_event__synthesize_threads(tool, process,
                                                       machine, mmap_data,
                                                       dirent, base, n);
                goto free_dirent;
        }
        if (thread_nr > n)
                thread_nr = n;

        synthesize_threads = calloc(sizeof(pthread_t), thread_nr);
        if (synthesize_threads == NULL)
                goto free_dirent;

        args = calloc(sizeof(*args), thread_nr);
        if (args == NULL)
                goto free_threads;

        num_per_thread = n / thread_nr;
        m = n % thread_nr;
        for (i = 0; i < thread_nr; i++) {
                args[i].tool = tool;
                args[i].process = process;
                args[i].machine = machine;
                args[i].mmap_data = mmap_data;
                args[i].dirent = dirent;
        }
        for (i = 0; i < m; i++) {
                args[i].num = num_per_thread + 1;
                args[i].start = i * args[i].num;
        }
        if (i != 0)
                base = args[i-1].start + args[i-1].num;
        for (j = i; j < thread_nr; j++) {
                args[j].num = num_per_thread;
                args[j].start = base + (j - i) * args[i].num;
        }

        for (i = 0; i < thread_nr; i++) {
                if (pthread_create(&synthesize_threads[i], NULL,
                                   synthesize_threads_worker, &args[i]))
                        goto out_join;
        }
        err = 0;
out_join:
        for (i = 0; i < thread_nr; i++)
                pthread_join(synthesize_threads[i], NULL);
        free(args);
free_threads:
        free(synthesize_threads);
free_dirent:
        for (i = 0; i < n; i++)
                zfree(&dirent[i]);
        free(dirent);

        return err;
}

int __weak perf_event__synthesize_extra_kmaps(struct perf_tool *tool __maybe_unused,
                                              perf_event__handler_t process __maybe_unused,
                                              struct machine *machine __maybe_unused)
{
        return 0;
}

static int __perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
                                                perf_event__handler_t process,
                                                struct machine *machine)
{
        size_t size;
        struct map *map = machine__kernel_map(machine);
        struct kmap *kmap;
        int err;
        union perf_event *event;

        if (map == NULL)
                return -1;

        kmap = map__kmap(map);
        if (!kmap->ref_reloc_sym)
                return -1;

        /*
         * We should get this from /sys/kernel/sections/.text, but till that is
         * available use this, and after it is use this as a fallback for older
         * kernels.
         */
        event = zalloc((sizeof(event->mmap) + machine->id_hdr_size));
        if (event == NULL) {
                pr_debug("Not enough memory synthesizing mmap event "
                         "for kernel modules\n");
                return -1;
        }

        if (machine__is_host(machine)) {
                /*
                 * kernel uses PERF_RECORD_MISC_USER for user space maps,
                 * see kernel/perf_event.c __perf_event_mmap
                 */
                event->header.misc = PERF_RECORD_MISC_KERNEL;
        } else {
                event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;
        }

        size = snprintf(event->mmap.filename, sizeof(event->mmap.filename),
                        "%s%s", machine->mmap_name, kmap->ref_reloc_sym->name) + 1;
        size = PERF_ALIGN(size, sizeof(u64));
        event->mmap.header.type = PERF_RECORD_MMAP;
        event->mmap.header.size = (sizeof(event->mmap) -
                        (sizeof(event->mmap.filename) - size) + machine->id_hdr_size);
        event->mmap.pgoff = kmap->ref_reloc_sym->addr;
        event->mmap.start = map->start;
        event->mmap.len   = map->end - event->mmap.start;
        event->mmap.pid   = machine->pid;

        err = perf_tool__process_synth_event(tool, event, machine, process);
        free(event);

        return err;
}

int perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
                                       perf_event__handler_t process,
                                       struct machine *machine)
{
        int err;

        err = __perf_event__synthesize_kernel_mmap(tool, process, machine);
        if (err < 0)
                return err;

        return perf_event__synthesize_extra_kmaps(tool, process, machine);
}

int perf_event__synthesize_thread_map2(struct perf_tool *tool,
                                      struct perf_thread_map *threads,
                                      perf_event__handler_t process,
                                      struct machine *machine)
{
        union perf_event *event;
        int i, err, size;

        size  = sizeof(event->thread_map);
        size += threads->nr * sizeof(event->thread_map.entries[0]);

        event = zalloc(size);
        if (!event)
                return -ENOMEM;

        event->header.type = PERF_RECORD_THREAD_MAP;
        event->header.size = size;
        event->thread_map.nr = threads->nr;

        for (i = 0; i < threads->nr; i++) {
                struct perf_record_thread_map_entry *entry = &event->thread_map.entries[i];
                char *comm = perf_thread_map__comm(threads, i);

                if (!comm)
                        comm = (char *) "";

                entry->pid = perf_thread_map__pid(threads, i);
                strncpy((char *) &entry->comm, comm, sizeof(entry->comm));
        }

        err = process(tool, event, NULL, machine);

        free(event);
        return err;
}

static void synthesize_cpus(struct cpu_map_entries *cpus,
                            struct perf_cpu_map *map)
{
        int i;

        cpus->nr = map->nr;

        for (i = 0; i < map->nr; i++)
                cpus->cpu[i] = map->map[i];
}

static void synthesize_mask(struct perf_record_record_cpu_map *mask,
                            struct perf_cpu_map *map, int max)
{
        int i;

        mask->nr = BITS_TO_LONGS(max);
        mask->long_size = sizeof(long);

        for (i = 0; i < map->nr; i++)
                set_bit(map->map[i], mask->mask);
}

static size_t cpus_size(struct perf_cpu_map *map)
{
        return sizeof(struct cpu_map_entries) + map->nr * sizeof(u16);
}

static size_t mask_size(struct perf_cpu_map *map, int *max)
{
        int i;

        *max = 0;

        for (i = 0; i < map->nr; i++) {
                /* bit possition of the cpu is + 1 */
                int bit = map->map[i] + 1;

                if (bit > *max)
                        *max = bit;
        }

        return sizeof(struct perf_record_record_cpu_map) + BITS_TO_LONGS(*max) * sizeof(long);
}

void *cpu_map_data__alloc(struct perf_cpu_map *map, size_t *size, u16 *type, int *max)
{
        size_t size_cpus, size_mask;
        bool is_dummy = perf_cpu_map__empty(map);

        /*
         * Both array and mask data have variable size based
         * on the number of cpus and their actual values.
         * The size of the 'struct perf_record_cpu_map_data' is:
         *
         *   array = size of 'struct cpu_map_entries' +
         *           number of cpus * sizeof(u64)
         *
         *   mask  = size of 'struct perf_record_record_cpu_map' +
         *           maximum cpu bit converted to size of longs
         *
         * and finaly + the size of 'struct perf_record_cpu_map_data'.
         */
        size_cpus = cpus_size(map);
        size_mask = mask_size(map, max);

        if (is_dummy || (size_cpus < size_mask)) {
                *size += size_cpus;
                *type  = PERF_CPU_MAP__CPUS;
        } else {
                *size += size_mask;
                *type  = PERF_CPU_MAP__MASK;
        }

        *size += sizeof(struct perf_record_cpu_map_data);
        *size = PERF_ALIGN(*size, sizeof(u64));
        return zalloc(*size);
}

void cpu_map_data__synthesize(struct perf_record_cpu_map_data *data, struct perf_cpu_map *map,
                              u16 type, int max)
{
        data->type = type;

        switch (type) {
        case PERF_CPU_MAP__CPUS:
                synthesize_cpus((struct cpu_map_entries *) data->data, map);
                break;
        case PERF_CPU_MAP__MASK:
                synthesize_mask((struct perf_record_record_cpu_map *)data->data, map, max);
        default:
                break;
        };
}

static struct perf_record_cpu_map *cpu_map_event__new(struct perf_cpu_map *map)
{
        size_t size = sizeof(struct perf_record_cpu_map);
        struct perf_record_cpu_map *event;
        int max;
        u16 type;

        event = cpu_map_data__alloc(map, &size, &type, &max);
        if (!event)
                return NULL;

        event->header.type = PERF_RECORD_CPU_MAP;
        event->header.size = size;
        event->data.type   = type;

        cpu_map_data__synthesize(&event->data, map, type, max);
        return event;
}

int perf_event__synthesize_cpu_map(struct perf_tool *tool,
                                   struct perf_cpu_map *map,
                                   perf_event__handler_t process,
                                   struct machine *machine)
{
        struct perf_record_cpu_map *event;
        int err;

        event = cpu_map_event__new(map);
        if (!event)
                return -ENOMEM;

        err = process(tool, (union perf_event *) event, NULL, machine);

        free(event);
        return err;
}

int perf_event__synthesize_stat_config(struct perf_tool *tool,
                                       struct perf_stat_config *config,
                                       perf_event__handler_t process,
                                       struct machine *machine)
{
        struct perf_record_stat_config *event;
        int size, i = 0, err;

        size  = sizeof(*event);
        size += (PERF_STAT_CONFIG_TERM__MAX * sizeof(event->data[0]));

        event = zalloc(size);
        if (!event)
                return -ENOMEM;

        event->header.type = PERF_RECORD_STAT_CONFIG;
        event->header.size = size;
        event->nr          = PERF_STAT_CONFIG_TERM__MAX;

#define ADD(__term, __val)                                      \
        event->data[i].tag = PERF_STAT_CONFIG_TERM__##__term;   \
        event->data[i].val = __val;                             \
        i++;

        ADD(AGGR_MODE,  config->aggr_mode)
        ADD(INTERVAL,   config->interval)
        ADD(SCALE,      config->scale)

        WARN_ONCE(i != PERF_STAT_CONFIG_TERM__MAX,
                  "stat config terms unbalanced\n");
#undef ADD

        err = process(tool, (union perf_event *) event, NULL, machine);

        free(event);
        return err;
}

int perf_event__synthesize_stat(struct perf_tool *tool,
                                u32 cpu, u32 thread, u64 id,
                                struct perf_counts_values *count,
                                perf_event__handler_t process,
                                struct machine *machine)
{
        struct perf_record_stat event;

        event.header.type = PERF_RECORD_STAT;
        event.header.size = sizeof(event);
        event.header.misc = 0;

        event.id        = id;
        event.cpu       = cpu;
        event.thread    = thread;
        event.val       = count->val;
        event.ena       = count->ena;
        event.run       = count->run;

        return process(tool, (union perf_event *) &event, NULL, machine);
}

int perf_event__synthesize_stat_round(struct perf_tool *tool,
                                      u64 evtime, u64 type,
                                      perf_event__handler_t process,
                                      struct machine *machine)
{
        struct perf_record_stat_round event;

        event.header.type = PERF_RECORD_STAT_ROUND;
        event.header.size = sizeof(event);
        event.header.misc = 0;

        event.time = evtime;
        event.type = type;

        return process(tool, (union perf_event *) &event, NULL, machine);
}

size_t perf_event__sample_event_size(const struct perf_sample *sample, u64 type, u64 read_format)
{
        size_t sz, result = sizeof(struct perf_record_sample);

        if (type & PERF_SAMPLE_IDENTIFIER)
                result += sizeof(u64);

        if (type & PERF_SAMPLE_IP)
                result += sizeof(u64);

        if (type & PERF_SAMPLE_TID)
                result += sizeof(u64);

        if (type & PERF_SAMPLE_TIME)
                result += sizeof(u64);

        if (type & PERF_SAMPLE_ADDR)
                result += sizeof(u64);

        if (type & PERF_SAMPLE_ID)
                result += sizeof(u64);

        if (type & PERF_SAMPLE_STREAM_ID)
                result += sizeof(u64);

        if (type & PERF_SAMPLE_CPU)
                result += sizeof(u64);

        if (type & PERF_SAMPLE_PERIOD)
                result += sizeof(u64);

        if (type & PERF_SAMPLE_READ) {
                result += sizeof(u64);
                if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
                        result += sizeof(u64);
                if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
                        result += sizeof(u64);
                /* PERF_FORMAT_ID is forced for PERF_SAMPLE_READ */
                if (read_format & PERF_FORMAT_GROUP) {
                        sz = sample->read.group.nr *
                             sizeof(struct sample_read_value);
                        result += sz;
                } else {
                        result += sizeof(u64);
                }
        }

        if (type & PERF_SAMPLE_CALLCHAIN) {
                sz = (sample->callchain->nr + 1) * sizeof(u64);
                result += sz;
        }

        if (type & PERF_SAMPLE_RAW) {
                result += sizeof(u32);
                result += sample->raw_size;
        }

        if (type & PERF_SAMPLE_BRANCH_STACK) {
                sz = sample->branch_stack->nr * sizeof(struct branch_entry);
                /* nr, hw_idx */
                sz += 2 * sizeof(u64);
                result += sz;
        }

        if (type & PERF_SAMPLE_REGS_USER) {
                if (sample->user_regs.abi) {
                        result += sizeof(u64);
                        sz = hweight64(sample->user_regs.mask) * sizeof(u64);
                        result += sz;
                } else {
                        result += sizeof(u64);
                }
        }

        if (type & PERF_SAMPLE_STACK_USER) {
                sz = sample->user_stack.size;
                result += sizeof(u64);
                if (sz) {
                        result += sz;
                        result += sizeof(u64);
                }
        }

        if (type & PERF_SAMPLE_WEIGHT)
                result += sizeof(u64);

        if (type & PERF_SAMPLE_DATA_SRC)
                result += sizeof(u64);

        if (type & PERF_SAMPLE_TRANSACTION)
                result += sizeof(u64);

        if (type & PERF_SAMPLE_REGS_INTR) {
                if (sample->intr_regs.abi) {
                        result += sizeof(u64);
                        sz = hweight64(sample->intr_regs.mask) * sizeof(u64);
                        result += sz;
                } else {
                        result += sizeof(u64);
                }
        }

        if (type & PERF_SAMPLE_PHYS_ADDR)
                result += sizeof(u64);

        if (type & PERF_SAMPLE_CGROUP)
                result += sizeof(u64);

        if (type & PERF_SAMPLE_AUX) {
                result += sizeof(u64);
                result += sample->aux_sample.size;
        }

        return result;
}

int perf_event__synthesize_sample(union perf_event *event, u64 type, u64 read_format,
                                  const struct perf_sample *sample)
{
        __u64 *array;
        size_t sz;
        /*
         * used for cross-endian analysis. See git commit 65014ab3
         * for why this goofiness is needed.
         */
        union u64_swap u;

        array = event->sample.array;

        if (type & PERF_SAMPLE_IDENTIFIER) {
                *array = sample->id;
                array++;
        }

        if (type & PERF_SAMPLE_IP) {
                *array = sample->ip;
                array++;
        }

        if (type & PERF_SAMPLE_TID) {
                u.val32[0] = sample->pid;
                u.val32[1] = sample->tid;
                *array = u.val64;
                array++;
        }

        if (type & PERF_SAMPLE_TIME) {
                *array = sample->time;
                array++;
        }

        if (type & PERF_SAMPLE_ADDR) {
                *array = sample->addr;
                array++;
        }

        if (type & PERF_SAMPLE_ID) {
                *array = sample->id;
                array++;
        }

        if (type & PERF_SAMPLE_STREAM_ID) {
                *array = sample->stream_id;
                array++;
        }

        if (type & PERF_SAMPLE_CPU) {
                u.val32[0] = sample->cpu;
                u.val32[1] = 0;
                *array = u.val64;
                array++;
        }

        if (type & PERF_SAMPLE_PERIOD) {
                *array = sample->period;
                array++;
        }

        if (type & PERF_SAMPLE_READ) {
                if (read_format & PERF_FORMAT_GROUP)
                        *array = sample->read.group.nr;
                else
                        *array = sample->read.one.value;
                array++;

                if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
                        *array = sample->read.time_enabled;
                        array++;
                }

                if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
                        *array = sample->read.time_running;
                        array++;
                }

                /* PERF_FORMAT_ID is forced for PERF_SAMPLE_READ */
                if (read_format & PERF_FORMAT_GROUP) {
                        sz = sample->read.group.nr *
                             sizeof(struct sample_read_value);
                        memcpy(array, sample->read.group.values, sz);
                        array = (void *)array + sz;
                } else {
                        *array = sample->read.one.id;
                        array++;
                }
        }

        if (type & PERF_SAMPLE_CALLCHAIN) {
                sz = (sample->callchain->nr + 1) * sizeof(u64);
                memcpy(array, sample->callchain, sz);
                array = (void *)array + sz;
        }

        if (type & PERF_SAMPLE_RAW) {
                u.val32[0] = sample->raw_size;
                *array = u.val64;
                array = (void *)array + sizeof(u32);

                memcpy(array, sample->raw_data, sample->raw_size);
                array = (void *)array + sample->raw_size;
        }

        if (type & PERF_SAMPLE_BRANCH_STACK) {
                sz = sample->branch_stack->nr * sizeof(struct branch_entry);
                /* nr, hw_idx */
                sz += 2 * sizeof(u64);
                memcpy(array, sample->branch_stack, sz);
                array = (void *)array + sz;
        }

        if (type & PERF_SAMPLE_REGS_USER) {
                if (sample->user_regs.abi) {
                        *array++ = sample->user_regs.abi;
                        sz = hweight64(sample->user_regs.mask) * sizeof(u64);
                        memcpy(array, sample->user_regs.regs, sz);
                        array = (void *)array + sz;
                } else {
                        *array++ = 0;
                }
        }

        if (type & PERF_SAMPLE_STACK_USER) {
                sz = sample->user_stack.size;
                *array++ = sz;
                if (sz) {
                        memcpy(array, sample->user_stack.data, sz);
                        array = (void *)array + sz;
                        *array++ = sz;
                }
        }

        if (type & PERF_SAMPLE_WEIGHT) {
                *array = sample->weight;
                array++;
        }

        if (type & PERF_SAMPLE_DATA_SRC) {
                *array = sample->data_src;
                array++;
        }

        if (type & PERF_SAMPLE_TRANSACTION) {
                *array = sample->transaction;
                array++;
        }

        if (type & PERF_SAMPLE_REGS_INTR) {
                if (sample->intr_regs.abi) {
                        *array++ = sample->intr_regs.abi;
                        sz = hweight64(sample->intr_regs.mask) * sizeof(u64);
                        memcpy(array, sample->intr_regs.regs, sz);
                        array = (void *)array + sz;
                } else {
                        *array++ = 0;
                }
        }

        if (type & PERF_SAMPLE_PHYS_ADDR) {
                *array = sample->phys_addr;
                array++;
        }

        if (type & PERF_SAMPLE_CGROUP) {
                *array = sample->cgroup;
                array++;
        }

        if (type & PERF_SAMPLE_AUX) {
                sz = sample->aux_sample.size;
                *array++ = sz;
                memcpy(array, sample->aux_sample.data, sz);
                array = (void *)array + sz;
        }

        return 0;
}

int perf_event__synthesize_id_index(struct perf_tool *tool, perf_event__handler_t process,
                                    struct evlist *evlist, struct machine *machine)
{
        union perf_event *ev;
        struct evsel *evsel;
        size_t nr = 0, i = 0, sz, max_nr, n;
        int err;

        pr_debug2("Synthesizing id index\n");

        max_nr = (UINT16_MAX - sizeof(struct perf_record_id_index)) /
                 sizeof(struct id_index_entry);

        evlist__for_each_entry(evlist, evsel)
                nr += evsel->core.ids;

        n = nr > max_nr ? max_nr : nr;
        sz = sizeof(struct perf_record_id_index) + n * sizeof(struct id_index_entry);
        ev = zalloc(sz);
        if (!ev)
                return -ENOMEM;

        ev->id_index.header.type = PERF_RECORD_ID_INDEX;
        ev->id_index.header.size = sz;
        ev->id_index.nr = n;

        evlist__for_each_entry(evlist, evsel) {
                u32 j;

                for (j = 0; j < evsel->core.ids; j++) {
                        struct id_index_entry *e;
                        struct perf_sample_id *sid;

                        if (i >= n) {
                                err = process(tool, ev, NULL, machine);
                                if (err)
                                        goto out_err;
                                nr -= n;
                                i = 0;
                        }

                        e = &ev->id_index.entries[i++];

                        e->id = evsel->core.id[j];

                        sid = perf_evlist__id2sid(evlist, e->id);
                        if (!sid) {
                                free(ev);
                                return -ENOENT;
                        }

                        e->idx = sid->idx;
                        e->cpu = sid->cpu;
                        e->tid = sid->tid;
                }
        }

        sz = sizeof(struct perf_record_id_index) + nr * sizeof(struct id_index_entry);
        ev->id_index.header.size = sz;
        ev->id_index.nr = nr;

        err = process(tool, ev, NULL, machine);
out_err:
        free(ev);

        return err;
}

int __machine__synthesize_threads(struct machine *machine, struct perf_tool *tool,
                                  struct target *target, struct perf_thread_map *threads,
                                  perf_event__handler_t process, bool data_mmap,
                                  unsigned int nr_threads_synthesize)
{
        if (target__has_task(target))
                return perf_event__synthesize_thread_map(tool, threads, process, machine, data_mmap);
        else if (target__has_cpu(target))
                return perf_event__synthesize_threads(tool, process,
                                                      machine, data_mmap,
                                                      nr_threads_synthesize);
        /* command specified */
        return 0;
}

int machine__synthesize_threads(struct machine *machine, struct target *target,
                                struct perf_thread_map *threads, bool data_mmap,
                                unsigned int nr_threads_synthesize)
{
        return __machine__synthesize_threads(machine, NULL, target, threads,
                                             perf_event__process, data_mmap,
                                             nr_threads_synthesize);
}

static struct perf_record_event_update *event_update_event__new(size_t size, u64 type, u64 id)
{
        struct perf_record_event_update *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 evsel *evsel,
                                             perf_event__handler_t process)
{
        size_t size = strlen(evsel->unit);
        struct perf_record_event_update *ev;
        int err;

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

        strlcpy(ev->data, evsel->unit, size + 1);
        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 evsel *evsel,
                                              perf_event__handler_t process)
{
        struct perf_record_event_update *ev;
        struct perf_record_event_update_scale *ev_data;
        int err;

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

        ev_data = (struct perf_record_event_update_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 evsel *evsel,
                                             perf_event__handler_t process)
{
        struct perf_record_event_update *ev;
        size_t len = strlen(evsel->name);
        int err;

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

        strlcpy(ev->data, evsel->name, len + 1);
        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 evsel *evsel,
                                             perf_event__handler_t process)
{
        size_t size = sizeof(struct perf_record_event_update);
        struct perf_record_event_update *ev;
        int max, err;
        u16 type;

        if (!evsel->core.own_cpus)
                return 0;

        ev = cpu_map_data__alloc(evsel->core.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->core.id[0];

        cpu_map_data__synthesize((struct perf_record_cpu_map_data *)ev->data,
                                 evsel->core.own_cpus, type, max);

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

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

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

        return err;
}

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

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

int perf_event__synthesize_extra_attr(struct perf_tool *tool, struct evlist *evsel_list,
                                      perf_event__handler_t process, bool is_pipe)
{
        struct evsel *evsel;
        int err;

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

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

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

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

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 = zalloc(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_tracing_data(struct perf_tool *tool, int fd, struct 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;

        /*
         * 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->core.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__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;

        if (!pos->hit)
                return 0;

        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);

        return process(tool, &ev, NULL, machine);
}

int perf_event__synthesize_stat_events(struct perf_stat_config *config, struct perf_tool *tool,
                                       struct evlist *evlist, perf_event__handler_t process, bool attrs)
{
        int err;

        if (attrs) {
                err = perf_event__synthesize_attrs(tool, evlist, process);
                if (err < 0) {
                        pr_err("Couldn't synthesize attrs.\n");
                        return err;
                }
        }

        err = perf_event__synthesize_extra_attr(tool, evlist, process, attrs);
        err = perf_event__synthesize_thread_map2(tool, evlist->core.threads, process, NULL);
        if (err < 0) {
                pr_err("Couldn't synthesize thread map.\n");
                return err;
        }

        err = perf_event__synthesize_cpu_map(tool, evlist->core.cpus, process, NULL);
        if (err < 0) {
                pr_err("Couldn't synthesize thread map.\n");
                return err;
        }

        err = perf_event__synthesize_stat_config(tool, config, process, NULL);
        if (err < 0) {
                pr_err("Couldn't synthesize config.\n");
                return err;
        }

        return 0;
}

int __weak perf_event__synth_time_conv(const struct perf_event_mmap_page *pc __maybe_unused,
                                       struct perf_tool *tool __maybe_unused,
                                       perf_event__handler_t process __maybe_unused,
                                       struct machine *machine __maybe_unused)
{
        return 0;
}

extern const struct perf_header_feature_ops feat_ops[HEADER_LAST_FEATURE];

int perf_event__synthesize_features(struct perf_tool *tool, struct perf_session *session,
                                    struct evlist *evlist, perf_event__handler_t process)
{
        struct perf_header *header = &session->header;
        struct perf_record_header_feature *fe;
        struct feat_fd ff;
        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;
        ff.ph = &session->header;

        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;
}