// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2008,2009, Steven Rostedt <srostedt@redhat.com>
 */
#include <dirent.h>
#include <mntent.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <stdbool.h>
#include <linux/list.h>
#include <linux/kernel.h>
#include <linux/zalloc.h>
#include <internal/lib.h> // page_size
#include <sys/param.h>

#include "trace-event.h"
#include "tracepoint.h"
#include <api/fs/tracing_path.h>
#include "evsel.h"
#include "debug.h"
#include "util.h"

#define VERSION "0.6"
#define MAX_EVENT_LENGTH 512

static int output_fd;

struct tracepoint_path {
        char *system;
        char *name;
        struct tracepoint_path *next;
};

/* unfortunately, you can not stat debugfs or proc files for size */
static int record_file(const char *file, ssize_t hdr_sz)
{
        unsigned long long size = 0;
        char buf[BUFSIZ], *sizep;
        off_t hdr_pos = lseek(output_fd, 0, SEEK_CUR);
        int r, fd;
        int err = -EIO;

        fd = open(file, O_RDONLY);
        if (fd < 0) {
                pr_debug("Can't read '%s'", file);
                return -errno;
        }

        /* put in zeros for file size, then fill true size later */
        if (hdr_sz) {
                if (write(output_fd, &size, hdr_sz) != hdr_sz)
                        goto out;
        }

        do {
                r = read(fd, buf, BUFSIZ);
                if (r > 0) {
                        size += r;
                        if (write(output_fd, buf, r) != r)
                                goto out;
                }
        } while (r > 0);

        /* ugh, handle big-endian hdr_size == 4 */
        sizep = (char*)&size;
        if (host_is_bigendian())
                sizep += sizeof(u64) - hdr_sz;

        if (hdr_sz && pwrite(output_fd, sizep, hdr_sz, hdr_pos) < 0) {
                pr_debug("writing file size failed\n");
                goto out;
        }

        err = 0;
out:
        close(fd);
        return err;
}

static int record_header_files(void)
{
        char *path = get_events_file("header_page");
        struct stat st;
        int err = -EIO;

        if (!path) {
                pr_debug("can't get tracing/events/header_page");
                return -ENOMEM;
        }

        if (stat(path, &st) < 0) {
                pr_debug("can't read '%s'", path);
                goto out;
        }

        if (write(output_fd, "header_page", 12) != 12) {
                pr_debug("can't write header_page\n");
                goto out;
        }

        if (record_file(path, 8) < 0) {
                pr_debug("can't record header_page file\n");
                goto out;
        }

        put_events_file(path);

        path = get_events_file("header_event");
        if (!path) {
                pr_debug("can't get tracing/events/header_event");
                err = -ENOMEM;
                goto out;
        }

        if (stat(path, &st) < 0) {
                pr_debug("can't read '%s'", path);
                goto out;
        }

        if (write(output_fd, "header_event", 13) != 13) {
                pr_debug("can't write header_event\n");
                goto out;
        }

        if (record_file(path, 8) < 0) {
                pr_debug("can't record header_event file\n");
                goto out;
        }

        err = 0;
out:
        put_events_file(path);
        return err;
}

static bool name_in_tp_list(char *sys, struct tracepoint_path *tps)
{
        while (tps) {
                if (!strcmp(sys, tps->name))
                        return true;
                tps = tps->next;
        }

        return false;
}

#define for_each_event_tps(dir, dent, tps)                      \
        while ((dent = readdir(dir)))                           \
                if (dent->d_type == DT_DIR &&                   \
                    (strcmp(dent->d_name, ".")) &&              \
                    (strcmp(dent->d_name, "..")))               \

static int copy_event_system(const char *sys, struct tracepoint_path *tps)
{
        struct dirent *dent;
        struct stat st;
        char *format;
        DIR *dir;
        int count = 0;
        int ret;
        int err;

        dir = opendir(sys);
        if (!dir) {
                pr_debug("can't read directory '%s'", sys);
                return -errno;
        }

        for_each_event_tps(dir, dent, tps) {
                if (!name_in_tp_list(dent->d_name, tps))
                        continue;

                if (asprintf(&format, "%s/%s/format", sys, dent->d_name) < 0) {
                        err = -ENOMEM;
                        goto out;
                }
                ret = stat(format, &st);
                free(format);
                if (ret < 0)
                        continue;
                count++;
        }

        if (write(output_fd, &count, 4) != 4) {
                err = -EIO;
                pr_debug("can't write count\n");
                goto out;
        }

        rewinddir(dir);
        for_each_event_tps(dir, dent, tps) {
                if (!name_in_tp_list(dent->d_name, tps))
                        continue;

                if (asprintf(&format, "%s/%s/format", sys, dent->d_name) < 0) {
                        err = -ENOMEM;
                        goto out;
                }
                ret = stat(format, &st);

                if (ret >= 0) {
                        err = record_file(format, 8);
                        if (err) {
                                free(format);
                                goto out;
                        }
                }
                free(format);
        }
        err = 0;
out:
        closedir(dir);
        return err;
}

static int record_ftrace_files(struct tracepoint_path *tps)
{
        char *path;
        int ret;

        path = get_events_file("ftrace");
        if (!path) {
                pr_debug("can't get tracing/events/ftrace");
                return -ENOMEM;
        }

        ret = copy_event_system(path, tps);

        put_tracing_file(path);

        return ret;
}

static bool system_in_tp_list(char *sys, struct tracepoint_path *tps)
{
        while (tps) {
                if (!strcmp(sys, tps->system))
                        return true;
                tps = tps->next;
        }

        return false;
}

static int record_event_files(struct tracepoint_path *tps)
{
        struct dirent *dent;
        struct stat st;
        char *path;
        char *sys;
        DIR *dir;
        int count = 0;
        int ret;
        int err;

        path = get_tracing_file("events");
        if (!path) {
                pr_debug("can't get tracing/events");
                return -ENOMEM;
        }

        dir = opendir(path);
        if (!dir) {
                err = -errno;
                pr_debug("can't read directory '%s'", path);
                goto out;
        }

        for_each_event_tps(dir, dent, tps) {
                if (strcmp(dent->d_name, "ftrace") == 0 ||
                    !system_in_tp_list(dent->d_name, tps))
                        continue;

                count++;
        }

        if (write(output_fd, &count, 4) != 4) {
                err = -EIO;
                pr_debug("can't write count\n");
                goto out;
        }

        rewinddir(dir);
        for_each_event_tps(dir, dent, tps) {
                if (strcmp(dent->d_name, "ftrace") == 0 ||
                    !system_in_tp_list(dent->d_name, tps))
                        continue;

                if (asprintf(&sys, "%s/%s", path, dent->d_name) < 0) {
                        err = -ENOMEM;
                        goto out;
                }
                ret = stat(sys, &st);
                if (ret >= 0) {
                        ssize_t size = strlen(dent->d_name) + 1;

                        if (write(output_fd, dent->d_name, size) != size ||
                            copy_event_system(sys, tps) < 0) {
                                err = -EIO;
                                free(sys);
                                goto out;
                        }
                }
                free(sys);
        }
        err = 0;
out:
        if (dir)
                closedir(dir);
        put_tracing_file(path);

        return err;
}

static int record_proc_kallsyms(void)
{
        unsigned long long size = 0;
        /*
         * Just to keep older perf.data file parsers happy, record a zero
         * sized kallsyms file, i.e. do the same thing that was done when
         * /proc/kallsyms (or something specified via --kallsyms, in a
         * different path) couldn't be read.
         */
        return write(output_fd, &size, 4) != 4 ? -EIO : 0;
}

static int record_ftrace_printk(void)
{
        unsigned int size;
        char *path;
        struct stat st;
        int ret, err = 0;

        path = get_tracing_file("printk_formats");
        if (!path) {
                pr_debug("can't get tracing/printk_formats");
                return -ENOMEM;
        }

        ret = stat(path, &st);
        if (ret < 0) {
                /* not found */
                size = 0;
                if (write(output_fd, &size, 4) != 4)
                        err = -EIO;
                goto out;
        }
        err = record_file(path, 4);

out:
        put_tracing_file(path);
        return err;
}

static int record_saved_cmdline(void)
{
        unsigned long long size;
        char *path;
        struct stat st;
        int ret, err = 0;

        path = get_tracing_file("saved_cmdlines");
        if (!path) {
                pr_debug("can't get tracing/saved_cmdline");
                return -ENOMEM;
        }

        ret = stat(path, &st);
        if (ret < 0) {
                /* not found */
                size = 0;
                if (write(output_fd, &size, 8) != 8)
                        err = -EIO;
                goto out;
        }
        err = record_file(path, 8);

out:
        put_tracing_file(path);
        return err;
}

static void
put_tracepoints_path(struct tracepoint_path *tps)
{
        while (tps) {
                struct tracepoint_path *t = tps;

                tps = tps->next;
                zfree(&t->name);
                zfree(&t->system);
                free(t);
        }
}

static struct tracepoint_path *tracepoint_id_to_path(u64 config)
{
        struct tracepoint_path *path = NULL;
        DIR *sys_dir, *evt_dir;
        struct dirent *sys_dirent, *evt_dirent;
        char id_buf[24];
        int fd;
        u64 id;
        char evt_path[MAXPATHLEN];
        char *dir_path;

        sys_dir = tracing_events__opendir();
        if (!sys_dir)
                return NULL;

        for_each_subsystem(sys_dir, sys_dirent) {
                dir_path = get_events_file(sys_dirent->d_name);
                if (!dir_path)
                        continue;
                evt_dir = opendir(dir_path);
                if (!evt_dir)
                        goto next;

                for_each_event(dir_path, evt_dir, evt_dirent) {

                        scnprintf(evt_path, MAXPATHLEN, "%s/%s/id", dir_path,
                                  evt_dirent->d_name);
                        fd = open(evt_path, O_RDONLY);
                        if (fd < 0)
                                continue;
                        if (read(fd, id_buf, sizeof(id_buf)) < 0) {
                                close(fd);
                                continue;
                        }
                        close(fd);
                        id = atoll(id_buf);
                        if (id == config) {
                                put_events_file(dir_path);
                                closedir(evt_dir);
                                closedir(sys_dir);
                                path = zalloc(sizeof(*path));
                                if (!path)
                                        return NULL;
                                if (asprintf(&path->system, "%.*s",
                                             MAX_EVENT_LENGTH, sys_dirent->d_name) < 0) {
                                        free(path);
                                        return NULL;
                                }
                                if (asprintf(&path->name, "%.*s",
                                             MAX_EVENT_LENGTH, evt_dirent->d_name) < 0) {
                                        zfree(&path->system);
                                        free(path);
                                        return NULL;
                                }
                                return path;
                        }
                }
                closedir(evt_dir);
next:
                put_events_file(dir_path);
        }

        closedir(sys_dir);
        return NULL;
}

char *tracepoint_id_to_name(u64 config)
{
        struct tracepoint_path *path = tracepoint_id_to_path(config);
        char *buf = NULL;

        if (path && asprintf(&buf, "%s:%s", path->system, path->name) < 0)
                buf = NULL;

        put_tracepoints_path(path);
        return buf;
}

static struct tracepoint_path *tracepoint_name_to_path(const char *name)
{
        struct tracepoint_path *path = zalloc(sizeof(*path));
        const char *str = strchr(name, ':');

        if (path == NULL || str == NULL) {
                free(path);
                return NULL;
        }

        path->system = strndup(name, str - name);
        path->name = strdup(str+1);

        if (path->system == NULL || path->name == NULL) {
                zfree(&path->system);
                zfree(&path->name);
                zfree(&path);
        }

        return path;
}

static struct tracepoint_path *
get_tracepoints_path(struct list_head *pattrs)
{
        struct tracepoint_path path, *ppath = &path;
        struct evsel *pos;
        int nr_tracepoints = 0;

        list_for_each_entry(pos, pattrs, core.node) {
                if (pos->core.attr.type != PERF_TYPE_TRACEPOINT)
                        continue;
                ++nr_tracepoints;

                if (pos->name) {
                        ppath->next = tracepoint_name_to_path(pos->name);
                        if (ppath->next)
                                goto next;

                        if (strchr(pos->name, ':') == NULL)
                                goto try_id;

                        goto error;
                }

try_id:
                ppath->next = tracepoint_id_to_path(pos->core.attr.config);
                if (!ppath->next) {
error:
                        pr_debug("No memory to alloc tracepoints list\n");
                        put_tracepoints_path(path.next);
                        return NULL;
                }
next:
                ppath = ppath->next;
        }

        return nr_tracepoints > 0 ? path.next : NULL;
}

bool have_tracepoints(struct list_head *pattrs)
{
        struct evsel *pos;

        list_for_each_entry(pos, pattrs, core.node)
                if (pos->core.attr.type == PERF_TYPE_TRACEPOINT)
                        return true;

        return false;
}

static int tracing_data_header(void)
{
        char buf[20];
        ssize_t size;

        /* just guessing this is someone's birthday.. ;) */
        buf[0] = 23;
        buf[1] = 8;
        buf[2] = 68;
        memcpy(buf + 3, "tracing", 7);

        if (write(output_fd, buf, 10) != 10)
                return -1;

        size = strlen(VERSION) + 1;
        if (write(output_fd, VERSION, size) != size)
                return -1;

        /* save endian */
        if (host_is_bigendian())
                buf[0] = 1;
        else
                buf[0] = 0;

        if (write(output_fd, buf, 1) != 1)
                return -1;

        /* save size of long */
        buf[0] = sizeof(long);
        if (write(output_fd, buf, 1) != 1)
                return -1;

        /* save page_size */
        if (write(output_fd, &page_size, 4) != 4)
                return -1;

        return 0;
}

struct tracing_data *tracing_data_get(struct list_head *pattrs,
                                      int fd, bool temp)
{
        struct tracepoint_path *tps;
        struct tracing_data *tdata;
        int err;

        output_fd = fd;

        tps = get_tracepoints_path(pattrs);
        if (!tps)
                return NULL;

        tdata = malloc(sizeof(*tdata));
        if (!tdata)
                return NULL;

        tdata->temp = temp;
        tdata->size = 0;

        if (temp) {
                int temp_fd;

                snprintf(tdata->temp_file, sizeof(tdata->temp_file),
                         "/tmp/perf-XXXXXX");
                if (!mkstemp(tdata->temp_file)) {
                        pr_debug("Can't make temp file");
                        free(tdata);
                        return NULL;
                }

                temp_fd = open(tdata->temp_file, O_RDWR);
                if (temp_fd < 0) {
                        pr_debug("Can't read '%s'", tdata->temp_file);
                        free(tdata);
                        return NULL;
                }

                /*
                 * Set the temp file the default output, so all the
                 * tracing data are stored into it.
                 */
                output_fd = temp_fd;
        }

        err = tracing_data_header();
        if (err)
                goto out;
        err = record_header_files();
        if (err)
                goto out;
        err = record_ftrace_files(tps);
        if (err)
                goto out;
        err = record_event_files(tps);
        if (err)
                goto out;
        err = record_proc_kallsyms();
        if (err)
                goto out;
        err = record_ftrace_printk();
        if (err)
                goto out;
        err = record_saved_cmdline();

out:
        /*
         * All tracing data are stored by now, we can restore
         * the default output file in case we used temp file.
         */
        if (temp) {
                tdata->size = lseek(output_fd, 0, SEEK_CUR);
                close(output_fd);
                output_fd = fd;
        }

        if (err)
                zfree(&tdata);

        put_tracepoints_path(tps);
        return tdata;
}

int tracing_data_put(struct tracing_data *tdata)
{
        int err = 0;

        if (tdata->temp) {
                err = record_file(tdata->temp_file, 0);
                unlink(tdata->temp_file);
        }

        free(tdata);
        return err;
}

int read_tracing_data(int fd, struct list_head *pattrs)
{
        int err;
        struct tracing_data *tdata;

        /*
         * We work over the real file, so we can write data
         * directly, no temp file is needed.
         */
        tdata = tracing_data_get(pattrs, fd, false);
        if (!tdata)
                return -ENOMEM;

        err = tracing_data_put(tdata);
        return err;
}