/*-
 * Copyright (c) 2007 Joerg Sonnenberger
 * All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``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 AUTHOR(S) 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.
 */

#include "archive_platform.h"

__FBSDID("$FreeBSD: src/lib/libarchive/archive_write_set_compression_program.c,v 1.3 2008/06/15 10:45:57 kientzle Exp $");

/* This capability is only available on POSIX systems. */
#if (!defined(HAVE_PIPE) || !defined(HAVE_FCNTL) || \
    !(defined(HAVE_FORK) || defined(HAVE_VFORK))) && (!defined(_WIN32) || defined(__CYGWIN__))
#include "archive.h"

/*
 * On non-Posix systems, allow the program to build, but choke if
 * this function is actually invoked.
 */
int
archive_write_set_compression_program(struct archive *_a, const char *cmd)
{
    archive_set_error(_a, -1,
        "External compression programs not supported on this platform");
    return (ARCHIVE_FATAL);
}

#else

#ifdef HAVE_SYS_WAIT_H
#  include <sys/wait.h>
#endif
#ifdef HAVE_ERRNO_H
#  include <errno.h>
#endif
#ifdef HAVE_FCNTL_H
#  include <fcntl.h>
#endif
#ifdef HAVE_STDLIB_H
#  include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#  include <string.h>
#endif

#include "archive.h"
#include "archive_private.h"
#include "archive_write_private.h"

#include "filter_fork.h"

struct private_data {
    char        *description;
    pid_t        child;
    int      child_stdin, child_stdout;

    char        *child_buf;
    size_t       child_buf_len, child_buf_avail;
};

static int  archive_compressor_program_finish(struct archive_write *);
static int  archive_compressor_program_init(struct archive_write *);
static int  archive_compressor_program_write(struct archive_write *,
            const void *, size_t);

/*
 * Allocate, initialize and return a archive object.
 */
int
archive_write_set_compression_program(struct archive *_a, const char *cmd)
{
    struct archive_write *a = (struct archive_write *)_a;
    __archive_check_magic(&a->archive, ARCHIVE_WRITE_MAGIC,
        ARCHIVE_STATE_NEW, "archive_write_set_compression_program");
    a->compressor.init = &archive_compressor_program_init;
    a->compressor.config = strdup(cmd);
    return (ARCHIVE_OK);
}

/*
 * Setup callback.
 */
static int
archive_compressor_program_init(struct archive_write *a)
{
    int ret;
    struct private_data *state;
    static const char *prefix = "Program: ";
    char *cmd = a->compressor.config;

    if (a->client_opener != NULL) {
        ret = (a->client_opener)(&a->archive, a->client_data);
        if (ret != ARCHIVE_OK)
            return (ret);
    }

    state = (struct private_data *)malloc(sizeof(*state));
    if (state == NULL) {
        archive_set_error(&a->archive, ENOMEM,
            "Can't allocate data for compression");
        return (ARCHIVE_FATAL);
    }
    memset(state, 0, sizeof(*state));

    a->archive.compression_code = ARCHIVE_COMPRESSION_PROGRAM;
    state->description = (char *)malloc(strlen(prefix) + strlen(cmd) + 1);
    strcpy(state->description, prefix);
    strcat(state->description, cmd);
    a->archive.compression_name = state->description;

    state->child_buf_len = a->bytes_per_block;
    state->child_buf_avail = 0;
    state->child_buf = malloc(state->child_buf_len);

    if (state->child_buf == NULL) {
        archive_set_error(&a->archive, ENOMEM,
            "Can't allocate data for compression buffer");
        free(state);
        return (ARCHIVE_FATAL);
    }

    if ((state->child = __archive_create_child(cmd,
         &state->child_stdin, &state->child_stdout)) == -1) {
        archive_set_error(&a->archive, EINVAL,
            "Can't initialise filter");
        free(state->child_buf);
        free(state);
        return (ARCHIVE_FATAL);
    }

    a->compressor.write = archive_compressor_program_write;
    a->compressor.finish = archive_compressor_program_finish;

    a->compressor.data = state;
    return (0);
}

static ssize_t
child_write(struct archive_write *a, const char *buf, size_t buf_len)
{
    struct private_data *state = a->compressor.data;
    ssize_t ret;

    if (state->child_stdin == -1)
        return (-1);

    if (buf_len == 0)
        return (-1);

restart_write:
    do {
        ret = write(state->child_stdin, buf, buf_len);
    } while (ret == -1 && errno == EINTR);

    if (ret > 0)
        return (ret);
    if (ret == 0) {
        close(state->child_stdin);
        state->child_stdin = -1;
        fcntl(state->child_stdout, F_SETFL, 0);
        return (0);
    }
    if (ret == -1 && errno != EAGAIN)
        return (-1);

    if (state->child_stdout == -1) {
        fcntl(state->child_stdin, F_SETFL, 0);
        __archive_check_child(state->child_stdin, state->child_stdout);
        goto restart_write;
    }

    do {
        ret = read(state->child_stdout,
            state->child_buf + state->child_buf_avail,
            state->child_buf_len - state->child_buf_avail);
    } while (ret == -1 && errno == EINTR);

    if (ret == 0 || (ret == -1 && errno == EPIPE)) {
        close(state->child_stdout);
        state->child_stdout = -1;
        fcntl(state->child_stdin, F_SETFL, 0);
        goto restart_write;
    }
    if (ret == -1 && errno == EAGAIN) {
        __archive_check_child(state->child_stdin, state->child_stdout);
        goto restart_write;
    }
    if (ret == -1)
        return (-1);

    state->child_buf_avail += ret;

    ret = (a->client_writer)(&a->archive, a->client_data,
        state->child_buf, state->child_buf_avail);
    if (ret <= 0)
        return (-1);

    if ((size_t)ret < state->child_buf_avail) {
        memmove(state->child_buf, state->child_buf + ret,
            state->child_buf_avail - ret);
    }
    state->child_buf_avail -= ret;
    a->archive.raw_position += ret;
    goto restart_write;
}

/*
 * Write data to the compressed stream.
 */
static int
archive_compressor_program_write(struct archive_write *a, const void *buff,
    size_t length)
{
    struct private_data *state;
    ssize_t ret;
    const char *buf;

    state = (struct private_data *)a->compressor.data;
    if (a->client_writer == NULL) {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER,
            "No write callback is registered?  "
            "This is probably an internal programming error.");
        return (ARCHIVE_FATAL);
    }

    buf = buff;
    while (length > 0) {
        ret = child_write(a, buf, length);
        if (ret == -1 || ret == 0) {
            archive_set_error(&a->archive, EIO,
                "Can't write to filter");
            return (ARCHIVE_FATAL);
        }
        length -= ret;
        buf += ret;
    }

    a->archive.file_position += length;
    return (ARCHIVE_OK);
}


/*
 * Finish the compression...
 */
static int
archive_compressor_program_finish(struct archive_write *a)
{
    int ret, status;
    ssize_t bytes_read, bytes_written;
    struct private_data *state;

    state = (struct private_data *)a->compressor.data;
    ret = 0;
    if (a->client_writer == NULL) {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER,
            "No write callback is registered?  "
            "This is probably an internal programming error.");
        ret = ARCHIVE_FATAL;
        goto cleanup;
    }

    /* XXX pad compressed data. */

    close(state->child_stdin);
    state->child_stdin = -1;
    fcntl(state->child_stdout, F_SETFL, 0);

    for (;;) {
        do {
            bytes_read = read(state->child_stdout,
                state->child_buf + state->child_buf_avail,
                state->child_buf_len - state->child_buf_avail);
        } while (bytes_read == -1 && errno == EINTR);

        if (bytes_read == 0 || (bytes_read == -1 && errno == EPIPE))
            break;

        if (bytes_read == -1) {
            archive_set_error(&a->archive, errno,
                "Read from filter failed unexpectedly.");
            ret = ARCHIVE_FATAL;
            goto cleanup;
        }
        state->child_buf_avail += bytes_read;

        bytes_written = (a->client_writer)(&a->archive, a->client_data,
            state->child_buf, state->child_buf_avail);
        if (bytes_written <= 0) {
            ret = ARCHIVE_FATAL;
            goto cleanup;
        }
        if ((size_t)bytes_written < state->child_buf_avail) {
            memmove(state->child_buf,
                state->child_buf + bytes_written,
                state->child_buf_avail - bytes_written);
        }
        state->child_buf_avail -= bytes_written;
        a->archive.raw_position += bytes_written;
    }

    /* XXX pad final compressed block. */

cleanup:
    /* Shut down the child. */
    if (state->child_stdin != -1)
        close(state->child_stdin);
    if (state->child_stdout != -1)
        close(state->child_stdout);
    while (waitpid(state->child, &status, 0) == -1 && errno == EINTR)
        continue;

    if (status != 0) {
        archive_set_error(&a->archive, EIO,
            "Filter exited with failure.");
        ret = ARCHIVE_FATAL;
    }

    /* Release our configuration data. */
    free(a->compressor.config);
    a->compressor.config = NULL;

    /* Release our private state data. */
    free(state->child_buf);
    free(state->description);
    free(state);
    return (ret);
}

#endif /* !defined(HAVE_PIPE) || !defined(HAVE_VFORK) || !defined(HAVE_FCNTL) */
