// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2009, Steven Rostedt <srostedt@redhat.com>
 */
#include <dirent.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 <sys/mman.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>

#include "trace-event.h"
#include "debug.h"

static int input_fd;

static ssize_t trace_data_size;
static bool repipe;

static int __do_read(int fd, void *buf, int size)
{
        int rsize = size;

        while (size) {
                int ret = read(fd, buf, size);

                if (ret <= 0)
                        return -1;

                if (repipe) {
                        int retw = write(STDOUT_FILENO, buf, ret);

                        if (retw <= 0 || retw != ret) {
                                pr_debug("repiping input file");
                                return -1;
                        }
                }

                size -= ret;
                buf += ret;
        }

        return rsize;
}

static int do_read(void *data, int size)
{
        int r;

        r = __do_read(input_fd, data, size);
        if (r <= 0) {
                pr_debug("reading input file (size expected=%d received=%d)",
                         size, r);
                return -1;
        }

        trace_data_size += r;

        return r;
}

/* If it fails, the next read will report it */
static void skip(int size)
{
        char buf[BUFSIZ];
        int r;

        while (size) {
                r = size > BUFSIZ ? BUFSIZ : size;
                do_read(buf, r);
                size -= r;
        }
}

static unsigned int read4(struct tep_handle *pevent)
{
        unsigned int data;

        if (do_read(&data, 4) < 0)
                return 0;
        return tep_read_number(pevent, &data, 4);
}

static unsigned long long read8(struct tep_handle *pevent)
{
        unsigned long long data;

        if (do_read(&data, 8) < 0)
                return 0;
        return tep_read_number(pevent, &data, 8);
}

static char *read_string(void)
{
        char buf[BUFSIZ];
        char *str = NULL;
        int size = 0;
        off_t r;
        char c;

        for (;;) {
                r = read(input_fd, &c, 1);
                if (r < 0) {
                        pr_debug("reading input file");
                        goto out;
                }

                if (!r) {
                        pr_debug("no data");
                        goto out;
                }

                if (repipe) {
                        int retw = write(STDOUT_FILENO, &c, 1);

                        if (retw <= 0 || retw != r) {
                                pr_debug("repiping input file string");
                                goto out;
                        }
                }

                buf[size++] = c;

                if (!c)
                        break;
        }

        trace_data_size += size;

        str = malloc(size);
        if (str)
                memcpy(str, buf, size);
out:
        return str;
}

static int read_proc_kallsyms(struct tep_handle *pevent)
{
        unsigned int size;

        size = read4(pevent);
        if (!size)
                return 0;
        /*
         * Just skip it, now that we configure libtraceevent to use the
         * tools/perf/ symbol resolver.
         *
         * We need to skip it so that we can continue parsing old perf.data
         * files, that contains this /proc/kallsyms payload.
         *
         * Newer perf.data files will have just the 4-bytes zeros "kallsyms
         * payload", so that older tools can continue reading it and interpret
         * it as "no kallsyms payload is present".
         */
        lseek(input_fd, size, SEEK_CUR);
        trace_data_size += size;
        return 0;
}

static int read_ftrace_printk(struct tep_handle *pevent)
{
        unsigned int size;
        char *buf;

        /* it can have 0 size */
        size = read4(pevent);
        if (!size)
                return 0;

        buf = malloc(size + 1);
        if (buf == NULL)
                return -1;

        if (do_read(buf, size) < 0) {
                free(buf);
                return -1;
        }

        buf[size] = '\0';

        parse_ftrace_printk(pevent, buf, size);

        free(buf);
        return 0;
}

static int read_header_files(struct tep_handle *pevent)
{
        unsigned long long size;
        char *header_page;
        char buf[BUFSIZ];
        int ret = 0;

        if (do_read(buf, 12) < 0)
                return -1;

        if (memcmp(buf, "header_page", 12) != 0) {
                pr_debug("did not read header page");
                return -1;
        }

        size = read8(pevent);

        header_page = malloc(size);
        if (header_page == NULL)
                return -1;

        if (do_read(header_page, size) < 0) {
                pr_debug("did not read header page");
                free(header_page);
                return -1;
        }

        if (!tep_parse_header_page(pevent, header_page, size,
                                   tep_get_long_size(pevent))) {
                /*
                 * The commit field in the page is of type long,
                 * use that instead, since it represents the kernel.
                 */
                tep_set_long_size(pevent, tep_get_header_page_size(pevent));
        }
        free(header_page);

        if (do_read(buf, 13) < 0)
                return -1;

        if (memcmp(buf, "header_event", 13) != 0) {
                pr_debug("did not read header event");
                return -1;
        }

        size = read8(pevent);
        skip(size);

        return ret;
}

static int read_ftrace_file(struct tep_handle *pevent, unsigned long long size)
{
        int ret;
        char *buf;

        buf = malloc(size);
        if (buf == NULL) {
                pr_debug("memory allocation failure\n");
                return -1;
        }

        ret = do_read(buf, size);
        if (ret < 0) {
                pr_debug("error reading ftrace file.\n");
                goto out;
        }

        ret = parse_ftrace_file(pevent, buf, size);
        if (ret < 0)
                pr_debug("error parsing ftrace file.\n");
out:
        free(buf);
        return ret;
}

static int read_event_file(struct tep_handle *pevent, char *sys,
                           unsigned long long size)
{
        int ret;
        char *buf;

        buf = malloc(size);
        if (buf == NULL) {
                pr_debug("memory allocation failure\n");
                return -1;
        }

        ret = do_read(buf, size);
        if (ret < 0)
                goto out;

        ret = parse_event_file(pevent, buf, size, sys);
        if (ret < 0)
                pr_debug("error parsing event file.\n");
out:
        free(buf);
        return ret;
}

static int read_ftrace_files(struct tep_handle *pevent)
{
        unsigned long long size;
        int count;
        int i;
        int ret;

        count = read4(pevent);

        for (i = 0; i < count; i++) {
                size = read8(pevent);
                ret = read_ftrace_file(pevent, size);
                if (ret)
                        return ret;
        }
        return 0;
}

static int read_event_files(struct tep_handle *pevent)
{
        unsigned long long size;
        char *sys;
        int systems;
        int count;
        int i,x;
        int ret;

        systems = read4(pevent);

        for (i = 0; i < systems; i++) {
                sys = read_string();
                if (sys == NULL)
                        return -1;

                count = read4(pevent);

                for (x=0; x < count; x++) {
                        size = read8(pevent);
                        ret = read_event_file(pevent, sys, size);
                        if (ret) {
                                free(sys);
                                return ret;
                        }
                }
                free(sys);
        }
        return 0;
}

static int read_saved_cmdline(struct tep_handle *pevent)
{
        unsigned long long size;
        char *buf;
        int ret;

        /* it can have 0 size */
        size = read8(pevent);
        if (!size)
                return 0;

        buf = malloc(size + 1);
        if (buf == NULL) {
                pr_debug("memory allocation failure\n");
                return -1;
        }

        ret = do_read(buf, size);
        if (ret < 0) {
                pr_debug("error reading saved cmdlines\n");
                goto out;
        }

        parse_saved_cmdline(pevent, buf, size);
        ret = 0;
out:
        free(buf);
        return ret;
}

ssize_t trace_report(int fd, struct trace_event *tevent, bool __repipe)
{
        char buf[BUFSIZ];
        char test[] = { 23, 8, 68 };
        char *version;
        int show_version = 0;
        int show_funcs = 0;
        int show_printk = 0;
        ssize_t size = -1;
        int file_bigendian;
        int host_bigendian;
        int file_long_size;
        int file_page_size;
        struct tep_handle *pevent = NULL;
        int err;

        repipe = __repipe;
        input_fd = fd;

        if (do_read(buf, 3) < 0)
                return -1;
        if (memcmp(buf, test, 3) != 0) {
                pr_debug("no trace data in the file");
                return -1;
        }

        if (do_read(buf, 7) < 0)
                return -1;
        if (memcmp(buf, "tracing", 7) != 0) {
                pr_debug("not a trace file (missing 'tracing' tag)");
                return -1;
        }

        version = read_string();
        if (version == NULL)
                return -1;
        if (show_version)
                printf("version = %s\n", version);

        if (do_read(buf, 1) < 0) {
                free(version);
                return -1;
        }
        file_bigendian = buf[0];
        host_bigendian = bigendian();

        if (trace_event__init(tevent)) {
                pr_debug("trace_event__init failed");
                goto out;
        }

        pevent = tevent->pevent;

        tep_set_flag(pevent, TEP_NSEC_OUTPUT);
        tep_set_file_bigendian(pevent, file_bigendian);
        tep_set_local_bigendian(pevent, host_bigendian);

        if (do_read(buf, 1) < 0)
                goto out;
        file_long_size = buf[0];

        file_page_size = read4(pevent);
        if (!file_page_size)
                goto out;

        tep_set_long_size(pevent, file_long_size);
        tep_set_page_size(pevent, file_page_size);

        err = read_header_files(pevent);
        if (err)
                goto out;
        err = read_ftrace_files(pevent);
        if (err)
                goto out;
        err = read_event_files(pevent);
        if (err)
                goto out;
        err = read_proc_kallsyms(pevent);
        if (err)
                goto out;
        err = read_ftrace_printk(pevent);
        if (err)
                goto out;
        if (atof(version) >= 0.6) {
                err = read_saved_cmdline(pevent);
                if (err)
                        goto out;
        }

        size = trace_data_size;
        repipe = false;

        if (show_funcs) {
                tep_print_funcs(pevent);
        } else if (show_printk) {
                tep_print_printk(pevent);
        }

        pevent = NULL;

out:
        if (pevent)
                trace_event__cleanup(tevent);
        free(version);
        return size;
}