/*
 * Copyright (c) 2003,2004 The DragonFly Project.  All rights reserved.
 * 
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com>
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name of The DragonFly Project nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific, prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * 
 * $DragonFly: src/sbin/jscan/jscan.c,v 1.13 2008/06/05 18:06:30 swildner Exp $
 */

#include "jscan.h"

static int donecheck(enum jdirection direction, struct jdata *jd,
                     int64_t transid);
static void usage(const char *av0);

int jmodes;
int fsync_opt;
int verbose_opt;
off_t prefix_file_size = 100 * 1024 * 1024;
off_t trans_count;
static enum jdirection jdirection = JD_FORWARDS;

static void jscan_do_output(struct jfile *, const char *, 
                            const char *, int64_t);
static void jscan_do_mirror(struct jfile *, const char *,
                            const char *, int64_t);
static void jscan_do_record(struct jfile *, const char *,
                            const char *, int64_t);
static void jscan_do_debug(struct jfile *, const char *,
                            const char *, int64_t);
static void fork_subprocess(struct jfile *,
                            void (*)(struct jfile *, const char *,
                                     const char *, int64_t),
                            const char *,
                            const char *, const char *, int64_t);

int
main(int ac, char **av)
{
    const char *input_prefix = NULL;
    char *output_transid_file = NULL;
    char *mirror_transid_file = NULL;
    const char *mirror_directory = ".";
    char *record_prefix = NULL;
    char *record_transid_file = NULL;
    struct jsession jsdebug;
    struct jsession jsoutput;
    struct jsession jsmirror;
    char *ptr;
    int64_t mirror_transid;
    int64_t output_transid;
    int64_t record_transid;
    int64_t transid;
    int input_fd;
    struct stat st;
    struct jfile *jf;
    struct jdata *jd;
    int ch;

    while ((ch = getopt(ac, av, "2c:dfm:o:s:uvw:D:O:W:F")) != -1) {
        switch(ch) {
        case '2':
            jmodes |= JMODEF_INPUT_FULL;
            break;
        case 'c':
            trans_count = strtoll(optarg, &ptr, 0);
            switch(*ptr) {
            case 't':
                trans_count *= 1024;
                /* fall through */
            case 'g':
                trans_count *= 1024;
                /* fall through */
            case 'm':
                trans_count *= 1024;
                /* fall through */
            case 'k':
                trans_count *= 1024;
                break;
            case 0:
                break;
            default:
                fprintf(stderr, "Bad suffix for value specified with -c, use 'k', 'm', 'g', 't', or nothing\n");
                usage(av[0]);
            }
            break;
        case 'd':
            jmodes |= JMODEF_DEBUG;
            break;
        case 'f':
            jmodes |= JMODEF_LOOP_FOREVER;
            break;
        case 'v':
            ++verbose_opt;
            break;
        case 'm':
            jmodes |= JMODEF_MIRROR;
            if (strcmp(optarg, "none") != 0)
                mirror_transid_file = optarg;
            break;
        case 'O':
            jmodes |= JMODEF_OUTPUT_FULL;
            /* fall through */
        case 'o':
            jmodes |= JMODEF_OUTPUT;
            if (strcmp(optarg, "none") != 0)
                output_transid_file = optarg;
            break;
        case 's':
            prefix_file_size = strtoll(optarg, &ptr, 0);
            switch(*ptr) {
            case 't':
                prefix_file_size *= 1024;
                /* fall through */
            case 'g':
                prefix_file_size *= 1024;
                /* fall through */
            case 'm':
                prefix_file_size *= 1024;
                /* fall through */
            case 'k':
                prefix_file_size *= 1024;
                break;
            case 0:
                break;
            default:
                fprintf(stderr, "Bad suffix for value specified with -s, use 'k', 'm', 'g', 't', or nothing\n");
                usage(av[0]);
            }
            break;
        case 'u':
            jdirection = JD_BACKWARDS;
            break;
        case 'W':
            jmodes |= JMODEF_RECORD_TMP;
            /* fall through */
        case 'w':
            jmodes |= JMODEF_RECORD;
            record_prefix = optarg;
            asprintf(&record_transid_file, "%s.transid", record_prefix);
            break;
        case 'D':
            mirror_directory = optarg;
            break;
        case 'F':
            ++fsync_opt;
            break;
        default:
            fprintf(stderr, "unknown option: -%c\n", optopt);
            usage(av[0]);
        }
    }

    /*
     * Sanity checks
     */
    if ((jmodes & JMODEF_COMMAND_MASK) == 0)
        usage(av[0]);
    if (optind > ac + 1)  {
        fprintf(stderr, "Only one input file or prefix may be specified,\n"
                        "or zero if stdin is to be the input.\n");
        usage(av[0]);
    }
    if (strcmp(mirror_directory, ".") != 0) {
        struct stat sb;
        if (stat(mirror_directory, &sb) != 0) {
            perror ("Could not stat mirror directory");
            usage(av[0]);
        }
        if (!S_ISDIR(sb.st_mode))
        {
            fprintf (stderr, "Mirror directory '%s' is not a directory\n", mirror_directory);
            usage(av[0]);
        }
    }
    if (jdirection == JD_BACKWARDS && (jmodes & (JMODEF_RECORD|JMODEF_OUTPUT))) {
        fprintf(stderr, "Undo mode is only good in mirroring mode and "
                        "cannot be mixed with other modes.\n");
        exit(1);
    }

    /*
     * STEP1 - OPEN INPUT
     *
     * The input will either be a pipe, a regular file, or a journaling 
     * file prefix.
     */
    jf = NULL;
    if (optind == ac) {
        input_prefix = "<stdin>";
        input_fd = 0;
        if (fstat(0, &st) < 0 || !S_ISREG(st.st_mode)) {
            jmodes |= JMODEF_INPUT_PIPE;
            if (jdirection == JD_BACKWARDS) {
                fprintf(stderr, "Cannot scan journals on pipes backwards\n");
                usage(av[0]);
            }
        }
        jf = jopen_fd(input_fd);
    } else if (stat(av[optind], &st) == 0 && S_ISREG(st.st_mode)) {
        input_prefix = av[optind];
        if ((input_fd = open(av[optind], O_RDONLY)) != 0) {
            jf = jopen_fd(input_fd);
        } else {
            jf = NULL;
        }
    } else {
        input_prefix = av[optind];
        jf = jopen_prefix(input_prefix, 0);
        jmodes |= JMODEF_INPUT_PREFIX;
    }
    if (jf == NULL) {
        fprintf(stderr, "Unable to open input %s: %s\n", 
                input_prefix, strerror(errno));
        exit(1);
    }

    /*
     * STEP 1 - SYNCHRONIZING THE INPUT STREAM
     *
     * Figure out the starting point for our various output modes.  Figure
     * out the earliest transaction id and try to seek to that point,
     * otherwise we might have to scan through terrabytes of data.
     *
     * Invalid transid's will be set to 0, but it should also be noted
     * that 0 is also a valid transid.
     */
    get_transid_from_file(output_transid_file, &output_transid,
                          JMODEF_OUTPUT_TRANSID_GOOD);
    get_transid_from_file(mirror_transid_file, &mirror_transid, 
                          JMODEF_MIRROR_TRANSID_GOOD);
    get_transid_from_file(record_transid_file, &record_transid, 
                          JMODEF_RECORD_TRANSID_GOOD);
    transid = LLONG_MAX;
    if ((jmodes & JMODEF_OUTPUT_TRANSID_GOOD) && output_transid < transid)
        transid = output_transid;
    if ((jmodes & JMODEF_MIRROR_TRANSID_GOOD) && mirror_transid < transid)
        transid = mirror_transid;
    if ((jmodes & JMODEF_RECORD_TRANSID_GOOD) && record_transid < transid)
        transid = record_transid;
    if ((jmodes & JMODEF_TRANSID_GOOD_MASK) == 0)
        transid = 0;
    if (verbose_opt) {
        if (jmodes & JMODEF_OUTPUT) {
            fprintf(stderr, "Starting transid for OUTPUT: %016jx\n",
                    (uintmax_t)output_transid);
        }
        if (jmodes & JMODEF_MIRROR) {
            fprintf(stderr, "Starting transid for MIRROR: %016jx\n",
                    (uintmax_t)mirror_transid);
        }
        if (jmodes & JMODEF_RECORD) {
            fprintf(stderr, "Starting transid for RECORD: %016jx\n",
                    (uintmax_t)record_transid);
        }
    }

    if (strcmp(mirror_directory, ".") != 0) {
        if (chdir (mirror_directory) != 0) {
            perror ("Could not enter mirror directory");
            exit (1);
        }
    }

    /*
     * Now it gets more difficult.  If we are recording then the input
     * could be representative of continuing data and not have any
     * prior, older data that the output or mirror modes might need.  Those
     * modes must work off the recording data even as we write to it.
     * In that case we fork and have the sub-processes work off the
     * record output.
     *
     * Then we take the input and start recording.
     */
    if (jmodes & JMODEF_RECORD) {
        if (jrecord_init(record_prefix) < 0) {
            fprintf(stderr, "Unable to initialize file set for: %s\n", 
                    record_prefix);
            exit(1);
        }
        if (jmodes & JMODEF_MIRROR) {
            fork_subprocess(jf, jscan_do_mirror, record_prefix, 
                            mirror_transid_file,
                            mirror_directory, mirror_transid);
            /* XXX ack stream for temporary record file removal */
        }
        if (jmodes & JMODEF_OUTPUT) {
            fork_subprocess(jf, jscan_do_output, record_prefix,
                            record_transid_file,
                            NULL, output_transid);
            /* XXX ack stream for temporary record file removal */
        }
        jscan_do_record(jf, record_transid_file, record_prefix, record_transid);
        exit(0);
    }

    /*
     * If the input is a prefix set we can just pass it to the appropriate
     * jscan_do_*() function.  If we are doing both output and mirroring
     * we fork the mirror and do the output in the foreground since that
     * is going to stdout.
     */
    if (jmodes & JMODEF_INPUT_PREFIX) {
        if ((jmodes & JMODEF_OUTPUT) && (jmodes & JMODEF_MIRROR)) {
            fork_subprocess(jf, jscan_do_mirror, input_prefix, 
                            mirror_transid_file,
                            mirror_directory, mirror_transid);
            jscan_do_output(jf, output_transid_file, NULL, output_transid);
        } else if (jmodes & JMODEF_OUTPUT) {
            jscan_do_output(jf, output_transid_file, NULL, output_transid);
        } else if (jmodes & JMODEF_MIRROR) {
            jscan_do_mirror(jf, mirror_transid_file, mirror_directory,
                            mirror_transid);
        } else if (jmodes & JMODEF_DEBUG) {
            jscan_do_debug(jf, NULL, NULL, 0);
        }
        exit(0);
    }

    /*
     * The input is not a prefix set and we are not recording, which means
     * we have to transfer the data on the input pipe to the output and
     * mirroring code on the fly.  This also means that we must keep track
     * of meta-data records in-memory.  However, if the input is a regular
     * file we *CAN* try to optimize where we start reading.
     *
     * NOTE: If the mirroring code encounters a transaction record that is
     * not marked begin, and it does not have the begin record, it will
     * attempt to locate the begin record if the input is not a pipe, then
     * seek back.
     */
    if ((jmodes & JMODEF_TRANSID_GOOD_MASK) && !(jmodes & JMODEF_INPUT_PIPE))
        jd = jseek(jf, transid, jdirection);
    else
        jd = jread(jf, NULL, jdirection);
    jmodes |= JMODEF_MEMORY_TRACKING;

    jsession_init(&jsdebug, jf, jdirection,
                  NULL, 0);
    jsession_init(&jsoutput, jf, jdirection, 
                  output_transid_file, output_transid);
    jsession_init(&jsmirror, jf, jdirection,
                  mirror_transid_file, mirror_transid);
    jsmirror.ss_mirror_directory = mirror_directory;

    while (jd != NULL) {
        if ((jmodes & JMODEF_DEBUG) && jsession_check(&jsdebug, jd))
            dump_debug(&jsdebug, jd);
        if ((jmodes & JMODEF_OUTPUT) && jsession_check(&jsoutput, jd))
            dump_output(&jsoutput, jd);
        if ((jmodes & JMODEF_MIRROR) && jsession_check(&jsmirror, jd))
            dump_mirror(&jsmirror, jd);
        if (donecheck(jdirection, jd, transid)) {
            jfree(jf, jd);
            break;
        }
        jd = jread(jf, jd, jdirection);
    }
    jclose(jf);
    jsession_term(&jsdebug);
    jsession_term(&jsoutput);
    jsession_term(&jsmirror);
    return(0);
}

/*
 * Returns one if we need to break out of our scanning loop, zero otherwise.
 */
static int
donecheck(enum jdirection direction, struct jdata *jd, int64_t transid)
{
    if (direction == JD_FORWARDS) {
        if (jd->jd_transid > transid && trans_count && --trans_count == 0)
            return(1);
    } else {
        if (jd->jd_transid <= transid && trans_count && --trans_count == 0)
            return(1);
    }
    return(0);
}

/*
 * When we have multiple commands and are writing to a prefix set, we can
 * 'background' the output and/or mirroring command and have the background
 * processes feed off the prefix set the foreground process is writing to.
 */
static void
fork_subprocess(struct jfile *jftoclose,
        void (*func)(struct jfile *, const char *, const char *, int64_t),
        const char *input_prefix, const char *transid_file, const char *info,
        int64_t transid)
{
    pid_t pid;
    struct jfile *jf;

    if ((pid = fork()) == 0) {
        jmodes &= ~(JMODEF_DEBUG | JMODEF_INPUT_PIPE);
        jmodes |= JMODEF_LOOP_FOREVER;  /* keep checking for new input */
        jclose(jftoclose);
        jf = jopen_prefix(input_prefix, 0);
        jmodes |= JMODEF_INPUT_PREFIX;
        func(jf, transid_file, info, transid);
        jclose(jf);
        exit(0);
    } else if (pid < 0) {
        fprintf(stderr, "fork(): %s\n", strerror(errno));
        exit(1);
    }
}

static void
jscan_do_output(struct jfile *jf, const char *output_transid_file, const char *dummy __unused, int64_t transid)
{
    struct jdata *jd;
    struct jsession jsdebug;
    struct jsession jsoutput;

    jsession_init(&jsdebug, jf, jdirection,
                  NULL, 0);
    jsession_init(&jsoutput, jf, jdirection,
                  output_transid_file, transid);

    if ((jmodes & JMODEF_OUTPUT_TRANSID_GOOD) && !(jmodes & JMODEF_INPUT_PIPE))
        jd = jseek(jf, transid, jdirection);
    else
        jd = jread(jf, NULL, jdirection);
    while (jd != NULL) {
        if ((jmodes & JMODEF_DEBUG) && jsession_check(&jsdebug, jd))
            dump_debug(&jsdebug, jd);
        if (jsession_check(&jsoutput, jd))
            dump_output(&jsoutput, jd);
        if (donecheck(jdirection, jd, transid)) {
            jfree(jf, jd);
            break;
        }
        jd = jread(jf, jd, jdirection);
    }
    jsession_term(&jsdebug);
    jsession_term(&jsoutput);
}

static void
jscan_do_mirror(struct jfile *jf, const char *mirror_transid_file, const char *mirror_directory, int64_t transid)
{
    struct jsession jsdebug;
    struct jsession jsmirror;
    struct jdata *jd;

    jsession_init(&jsdebug, jf, jdirection,
                  NULL, 0);
    jsession_init(&jsmirror, jf, jdirection,
                  mirror_transid_file, transid);
    jsmirror.ss_mirror_directory = mirror_directory;

    if ((jmodes & JMODEF_MIRROR_TRANSID_GOOD) && !(jmodes & JMODEF_INPUT_PIPE))
        jd = jseek(jf, transid, jdirection);
    else
        jd = jread(jf, NULL, jdirection);
    while (jd != NULL) {
        if ((jmodes & JMODEF_DEBUG) && jsession_check(&jsdebug, jd))
            dump_debug(&jsdebug, jd);
        if (jsession_check(&jsmirror, jd))
            dump_mirror(&jsmirror, jd);
        if (donecheck(jdirection, jd, transid)) {
            jfree(jf, jd);
            break;
        }
        jd = jread(jf, jd, jdirection);
    }
    jsession_term(&jsdebug);
    jsession_term(&jsmirror);
}

static void
jscan_do_record(struct jfile *jfin, const char *record_transid_file, const char *prefix, int64_t transid)
{
    struct jsession jsdebug;
    struct jsession jsrecord;
    struct jdata *jd;

    jsession_init(&jsdebug, jfin, jdirection,
                  NULL, 0);
    jsession_init(&jsrecord, jfin, jdirection,
                  record_transid_file, transid);

    assert(jdirection == JD_FORWARDS);
    jsrecord.ss_jfout = jopen_prefix(prefix, 1);
    if (jsrecord.ss_jfout == NULL) {
        fprintf(stderr, "Unable to open prefix set for writing: %s\n", prefix);
        exit(1);
    }
    if ((jmodes & JMODEF_RECORD_TRANSID_GOOD) && !(jmodes & JMODEF_INPUT_PIPE))
        jd = jseek(jfin, transid, jdirection);
    else
        jd = jread(jfin, NULL, jdirection);
    while (jd != NULL) {
        if ((jmodes & JMODEF_DEBUG) && jsession_check(&jsdebug, jd))
            dump_debug(&jsdebug, jd);
        if (jsession_check(&jsrecord, jd))
            dump_record(&jsrecord, jd);
        if (donecheck(jdirection, jd, transid)) {
            jfree(jfin, jd);
            break;
        }
        jd = jread(jfin, jd, jdirection);
    }
    jclose(jsrecord.ss_jfout);
    jsrecord.ss_jfout = NULL;
    jsession_term(&jsdebug);
    jsession_term(&jsrecord);
}

static void
jscan_do_debug(struct jfile *jf, const char *dummy1 __unused,
               const char *dummy __unused, int64_t transid __unused)
{
    struct jsession jsdebug;
    struct jdata *jd;

    jsession_init(&jsdebug, jf, jdirection,
                  NULL, 0);
    jd = NULL;
    while ((jd = jread(jf, jd, jdirection)) != NULL) {
        if (jsession_check(&jsdebug, jd))
            dump_debug(&jsdebug, jd);
        if (donecheck(jdirection, jd, transid)) {
            jfree(jf, jd);
            break;
        }
    }
    jsession_term(&jsdebug);
}

static void
usage(const char *av0)
{
    fprintf(stderr, 
        "%s [-2dfuvF] [-D dir] [-m mirror_transid_file/none]\n"
        "\t[-o/O output_transid_file/none]\n"
        "\t[-s size[kmgt]] -w/W record_prefix] [input_file/input_prefix]\n",
        av0);
    exit(1);
}