acpi: Narrow workaround for broken interrupt settings

[dragonfly.git] / contrib / libarchive / libarchive / archive_write.c

/*-
 * Copyright (c) 2003-2010 Tim Kientzle
 * 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: head/lib/libarchive/archive_write.c 201099 2009-12-28 03:03:00Z kientzle $");

/*
 * This file contains the "essential" portions of the write API, that
 * is, stuff that will essentially always be used by any client that
 * actually needs to write an archive.  Optional pieces have been, as
 * far as possible, separated out into separate files to reduce
 * needlessly bloating statically-linked clients.
 */

#ifdef HAVE_SYS_WAIT_H
#include <sys/wait.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_LIMITS_H
#include <limits.h>
#endif
#include <stdio.h>
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#include <time.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

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

static int      _archive_filter_code(struct archive *, int);
static const char *_archive_filter_name(struct archive *, int);
static int64_t  _archive_filter_bytes(struct archive *, int);
static int  _archive_write_filter_count(struct archive *);
static int      _archive_write_close(struct archive *);
static int      _archive_write_free(struct archive *);
static int      _archive_write_header(struct archive *, struct archive_entry *);
static int      _archive_write_finish_entry(struct archive *);
static ssize_t  _archive_write_data(struct archive *, const void *, size_t);

struct archive_none {
        size_t buffer_size;
        size_t avail;
        char *buffer;
        char *next;
};

static const struct archive_vtable
archive_write_vtable = {
        .archive_close = _archive_write_close,
        .archive_filter_bytes = _archive_filter_bytes,
        .archive_filter_code = _archive_filter_code,
        .archive_filter_name = _archive_filter_name,
        .archive_filter_count = _archive_write_filter_count,
        .archive_free = _archive_write_free,
        .archive_write_header = _archive_write_header,
        .archive_write_finish_entry = _archive_write_finish_entry,
        .archive_write_data = _archive_write_data,
};

/*
 * Allocate, initialize and return an archive object.
 */
struct archive *
archive_write_new(void)
{
        struct archive_write *a;
        unsigned char *nulls;

        a = (struct archive_write *)calloc(1, sizeof(*a));
        if (a == NULL)
                return (NULL);
        a->archive.magic = ARCHIVE_WRITE_MAGIC;
        a->archive.state = ARCHIVE_STATE_NEW;
        a->archive.vtable = &archive_write_vtable;
        /*
         * The value 10240 here matches the traditional tar default,
         * but is otherwise arbitrary.
         * TODO: Set the default block size from the format selected.
         */
        a->bytes_per_block = 10240;
        a->bytes_in_last_block = -1;    /* Default */

        /* Initialize a block of nulls for padding purposes. */
        a->null_length = 1024;
        nulls = (unsigned char *)calloc(1, a->null_length);
        if (nulls == NULL) {
                free(a);
                return (NULL);
        }
        a->nulls = nulls;
        return (&a->archive);
}

/*
 * Set the block size.  Returns 0 if successful.
 */
int
archive_write_set_bytes_per_block(struct archive *_a, int bytes_per_block)
{
        struct archive_write *a = (struct archive_write *)_a;
        archive_check_magic(&a->archive, ARCHIVE_WRITE_MAGIC,
            ARCHIVE_STATE_NEW, "archive_write_set_bytes_per_block");
        a->bytes_per_block = bytes_per_block;
        return (ARCHIVE_OK);
}

/*
 * Get the current block size.  -1 if it has never been set.
 */
int
archive_write_get_bytes_per_block(struct archive *_a)
{
        struct archive_write *a = (struct archive_write *)_a;
        archive_check_magic(&a->archive, ARCHIVE_WRITE_MAGIC,
            ARCHIVE_STATE_ANY, "archive_write_get_bytes_per_block");
        return (a->bytes_per_block);
}

/*
 * Set the size for the last block.
 * Returns 0 if successful.
 */
int
archive_write_set_bytes_in_last_block(struct archive *_a, int bytes)
{
        struct archive_write *a = (struct archive_write *)_a;
        archive_check_magic(&a->archive, ARCHIVE_WRITE_MAGIC,
            ARCHIVE_STATE_ANY, "archive_write_set_bytes_in_last_block");
        a->bytes_in_last_block = bytes;
        return (ARCHIVE_OK);
}

/*
 * Return the value set above.  -1 indicates it has not been set.
 */
int
archive_write_get_bytes_in_last_block(struct archive *_a)
{
        struct archive_write *a = (struct archive_write *)_a;
        archive_check_magic(&a->archive, ARCHIVE_WRITE_MAGIC,
            ARCHIVE_STATE_ANY, "archive_write_get_bytes_in_last_block");
        return (a->bytes_in_last_block);
}

/*
 * dev/ino of a file to be rejected.  Used to prevent adding
 * an archive to itself recursively.
 */
int
archive_write_set_skip_file(struct archive *_a, la_int64_t d, la_int64_t i)
{
        struct archive_write *a = (struct archive_write *)_a;
        archive_check_magic(&a->archive, ARCHIVE_WRITE_MAGIC,
            ARCHIVE_STATE_ANY, "archive_write_set_skip_file");
        a->skip_file_set = 1;
        a->skip_file_dev = d;
        a->skip_file_ino = i;
        return (ARCHIVE_OK);
}

/*
 * Allocate and return the next filter structure.
 */
struct archive_write_filter *
__archive_write_allocate_filter(struct archive *_a)
{
        struct archive_write *a = (struct archive_write *)_a;
        struct archive_write_filter *f;

        f = calloc(1, sizeof(*f));
        f->archive = _a;
        f->state = ARCHIVE_WRITE_FILTER_STATE_NEW;
        if (a->filter_first == NULL)
                a->filter_first = f;
        else
                a->filter_last->next_filter = f;
        a->filter_last = f;
        return f;
}

/*
 * Write data to a particular filter.
 */
int
__archive_write_filter(struct archive_write_filter *f,
    const void *buff, size_t length)
{
        int r;
        /* Never write to non-open filters */
        if (f->state != ARCHIVE_WRITE_FILTER_STATE_OPEN)
                return(ARCHIVE_FATAL);
        if (length == 0)
                return(ARCHIVE_OK);
        if (f->write == NULL)
                /* If unset, a fatal error has already occurred, so this filter
                 * didn't open. We cannot write anything. */
                return(ARCHIVE_FATAL);
        r = (f->write)(f, buff, length);
        f->bytes_written += length;
        return (r);
}

/*
 * Recursive function for opening the filter chain
 * Last filter is opened first
 */
static int
__archive_write_open_filter(struct archive_write_filter *f)
{
        int ret;

        ret = ARCHIVE_OK;
        if (f->next_filter != NULL)
                ret = __archive_write_open_filter(f->next_filter);
        if (ret != ARCHIVE_OK)
                return (ret);
        if (f->state != ARCHIVE_WRITE_FILTER_STATE_NEW)
                return (ARCHIVE_FATAL);
        if (f->open == NULL) {
                f->state = ARCHIVE_WRITE_FILTER_STATE_OPEN;
                return (ARCHIVE_OK);
        }
        ret = (f->open)(f);
        if (ret == ARCHIVE_OK)
                f->state = ARCHIVE_WRITE_FILTER_STATE_OPEN;
        else
                f->state = ARCHIVE_WRITE_FILTER_STATE_FATAL;
        return (ret);
}

/*
 * Open all filters
 */
static int
__archive_write_filters_open(struct archive_write *a)
{
        return (__archive_write_open_filter(a->filter_first));
}

/*
 * Close all filtes
 */
static int
__archive_write_filters_close(struct archive_write *a)
{
        struct archive_write_filter *f;
        int ret, ret1;
        ret = ARCHIVE_OK;
        for (f = a->filter_first; f != NULL; f = f->next_filter) {
                /* Do not close filters that are not open */
                if (f->state == ARCHIVE_WRITE_FILTER_STATE_OPEN) {
                        if (f->close != NULL) {
                                ret1 = (f->close)(f);
                                if (ret1 < ret)
                                        ret = ret1;
                                if (ret1 == ARCHIVE_OK) {
                                        f->state =
                                            ARCHIVE_WRITE_FILTER_STATE_CLOSED;
                                } else {
                                        f->state =
                                            ARCHIVE_WRITE_FILTER_STATE_FATAL;
                                }
                        } else
                                f->state = ARCHIVE_WRITE_FILTER_STATE_CLOSED;
                }
        }
        return (ret);
}

int
__archive_write_output(struct archive_write *a, const void *buff, size_t length)
{
        return (__archive_write_filter(a->filter_first, buff, length));
}

int
__archive_write_nulls(struct archive_write *a, size_t length)
{
        if (length == 0)
                return (ARCHIVE_OK);

        while (length > 0) {
                size_t to_write = length < a->null_length ? length : a->null_length;
                int r = __archive_write_output(a, a->nulls, to_write);
                if (r < ARCHIVE_OK)
                        return (r);
                length -= to_write;
        }
        return (ARCHIVE_OK);
}

static int
archive_write_client_open(struct archive_write_filter *f)
{
        struct archive_write *a = (struct archive_write *)f->archive;
        struct archive_none *state;
        void *buffer;
        size_t buffer_size;
        int ret;

        f->bytes_per_block = archive_write_get_bytes_per_block(f->archive);
        f->bytes_in_last_block =
            archive_write_get_bytes_in_last_block(f->archive);
        buffer_size = f->bytes_per_block;

        state = (struct archive_none *)calloc(1, sizeof(*state));
        buffer = (char *)malloc(buffer_size);
        if (state == NULL || buffer == NULL) {
                free(state);
                free(buffer);
                archive_set_error(f->archive, ENOMEM,
                    "Can't allocate data for output buffering");
                return (ARCHIVE_FATAL);
        }

        state->buffer_size = buffer_size;
        state->buffer = buffer;
        state->next = state->buffer;
        state->avail = state->buffer_size;
        f->data = state;

        if (a->client_opener == NULL)
                return (ARCHIVE_OK);
        ret = a->client_opener(f->archive, a->client_data);
        if (ret != ARCHIVE_OK) {
                free(state->buffer);
                free(state);
                f->data = NULL;
        }
        return (ret);
}

static int
archive_write_client_write(struct archive_write_filter *f,
    const void *_buff, size_t length)
{
        struct archive_write *a = (struct archive_write *)f->archive;
        struct archive_none *state = (struct archive_none *)f->data;
        const char *buff = (const char *)_buff;
        ssize_t remaining, to_copy;
        ssize_t bytes_written;

        remaining = length;

        /*
         * If there is no buffer for blocking, just pass the data
         * straight through to the client write callback.  In
         * particular, this supports "no write delay" operation for
         * special applications.  Just set the block size to zero.
         */
        if (state->buffer_size == 0) {
                while (remaining > 0) {
                        bytes_written = (a->client_writer)(&a->archive,
                            a->client_data, buff, remaining);
                        if (bytes_written <= 0)
                                return (ARCHIVE_FATAL);
                        remaining -= bytes_written;
                        buff += bytes_written;
                }
                return (ARCHIVE_OK);
        }

        /* If the copy buffer isn't empty, try to fill it. */
        if (state->avail < state->buffer_size) {
                /* If buffer is not empty... */
                /* ... copy data into buffer ... */
                to_copy = ((size_t)remaining > state->avail) ?
                        state->avail : (size_t)remaining;
                memcpy(state->next, buff, to_copy);
                state->next += to_copy;
                state->avail -= to_copy;
                buff += to_copy;
                remaining -= to_copy;
                /* ... if it's full, write it out. */
                if (state->avail == 0) {
                        char *p = state->buffer;
                        size_t to_write = state->buffer_size;
                        while (to_write > 0) {
                                bytes_written = (a->client_writer)(&a->archive,
                                    a->client_data, p, to_write);
                                if (bytes_written <= 0)
                                        return (ARCHIVE_FATAL);
                                if ((size_t)bytes_written > to_write) {
                                        archive_set_error(&(a->archive),
                                            -1, "write overrun");
                                        return (ARCHIVE_FATAL);
                                }
                                p += bytes_written;
                                to_write -= bytes_written;
                        }
                        state->next = state->buffer;
                        state->avail = state->buffer_size;
                }
        }

        while ((size_t)remaining >= state->buffer_size) {
                /* Write out full blocks directly to client. */
                bytes_written = (a->client_writer)(&a->archive,
                    a->client_data, buff, state->buffer_size);
                if (bytes_written <= 0)
                        return (ARCHIVE_FATAL);
                buff += bytes_written;
                remaining -= bytes_written;
        }

        if (remaining > 0) {
                /* Copy last bit into copy buffer. */
                memcpy(state->next, buff, remaining);
                state->next += remaining;
                state->avail -= remaining;
        }
        return (ARCHIVE_OK);
}

static int
archive_write_client_free(struct archive_write_filter *f)
{
        struct archive_write *a = (struct archive_write *)f->archive;

        if (a->client_freer)
                (*a->client_freer)(&a->archive, a->client_data);
        a->client_data = NULL;

        /* Clear passphrase. */
        if (a->passphrase != NULL) {
                memset(a->passphrase, 0, strlen(a->passphrase));
                free(a->passphrase);
                a->passphrase = NULL;
        }

        return (ARCHIVE_OK);
}

static int
archive_write_client_close(struct archive_write_filter *f)
{
        struct archive_write *a = (struct archive_write *)f->archive;
        struct archive_none *state = (struct archive_none *)f->data;
        ssize_t block_length;
        ssize_t target_block_length;
        ssize_t bytes_written;
        size_t to_write;
        char *p;
        int ret = ARCHIVE_OK;

        /* If there's pending data, pad and write the last block */
        if (state->next != state->buffer) {
                block_length = state->buffer_size - state->avail;

                /* Tricky calculation to determine size of last block */
                if (a->bytes_in_last_block <= 0)
                        /* Default or Zero: pad to full block */
                        target_block_length = a->bytes_per_block;
                else
                        /* Round to next multiple of bytes_in_last_block. */
                        target_block_length = a->bytes_in_last_block *
                            ( (block_length + a->bytes_in_last_block - 1) /
                                a->bytes_in_last_block);
                if (target_block_length > a->bytes_per_block)
                        target_block_length = a->bytes_per_block;
                if (block_length < target_block_length) {
                        memset(state->next, 0,
                            target_block_length - block_length);
                        block_length = target_block_length;
                }
                p = state->buffer;
                to_write = block_length;
                while (to_write > 0) {
                        bytes_written = (a->client_writer)(&a->archive,
                            a->client_data, p, to_write);
                        if (bytes_written <= 0) {
                                ret = ARCHIVE_FATAL;
                                break;
                        }
                        if ((size_t)bytes_written > to_write) {
                                archive_set_error(&(a->archive),
                                                  -1, "write overrun");
                                ret = ARCHIVE_FATAL;
                                break;
                        }
                        p += bytes_written;
                        to_write -= bytes_written;
                }
        }
        if (a->client_closer)
                (*a->client_closer)(&a->archive, a->client_data);
        free(state->buffer);
        free(state);

        /* Clear the close handler myself not to be called again. */
        f->state = ARCHIVE_WRITE_FILTER_STATE_CLOSED;
        return (ret);
}

/*
 * Open the archive using the current settings.
 */
int
archive_write_open2(struct archive *_a, void *client_data,
    archive_open_callback *opener, archive_write_callback *writer,
    archive_close_callback *closer, archive_free_callback *freer)
{
        struct archive_write *a = (struct archive_write *)_a;
        struct archive_write_filter *client_filter;
        int ret, r1;

        archive_check_magic(&a->archive, ARCHIVE_WRITE_MAGIC,
            ARCHIVE_STATE_NEW, "archive_write_open");
        archive_clear_error(&a->archive);

        a->client_writer = writer;
        a->client_opener = opener;
        a->client_closer = closer;
        a->client_freer = freer;
        a->client_data = client_data;

        client_filter = __archive_write_allocate_filter(_a);
        client_filter->open = archive_write_client_open;
        client_filter->write = archive_write_client_write;
        client_filter->close = archive_write_client_close;
        client_filter->free = archive_write_client_free;

        ret = __archive_write_filters_open(a);
        if (ret < ARCHIVE_WARN) {
                r1 = __archive_write_filters_close(a);
                __archive_write_filters_free(_a);
                return (r1 < ret ? r1 : ret);
        }

        a->archive.state = ARCHIVE_STATE_HEADER;
        if (a->format_init)
                ret = (a->format_init)(a);
        return (ret);
}

int
archive_write_open(struct archive *_a, void *client_data,
    archive_open_callback *opener, archive_write_callback *writer,
    archive_close_callback *closer)
{
        return archive_write_open2(_a, client_data, opener, writer,
            closer, NULL);
}

/*
 * Close out the archive.
 */
static int
_archive_write_close(struct archive *_a)
{
        struct archive_write *a = (struct archive_write *)_a;
        int r = ARCHIVE_OK, r1 = ARCHIVE_OK;

        archive_check_magic(&a->archive, ARCHIVE_WRITE_MAGIC,
            ARCHIVE_STATE_ANY | ARCHIVE_STATE_FATAL,
            "archive_write_close");
        if (a->archive.state == ARCHIVE_STATE_NEW
            || a->archive.state == ARCHIVE_STATE_CLOSED)
                return (ARCHIVE_OK); /* Okay to close() when not open. */

        archive_clear_error(&a->archive);

        /* Finish the last entry if a finish callback is specified */
        if (a->archive.state == ARCHIVE_STATE_DATA
            && a->format_finish_entry != NULL)
                r = ((a->format_finish_entry)(a));

        /* Finish off the archive. */
        /* TODO: have format closers invoke compression close. */
        if (a->format_close != NULL) {
                r1 = (a->format_close)(a);
                if (r1 < r)
                        r = r1;
        }

        /* Finish the compression and close the stream. */
        r1 = __archive_write_filters_close(a);
        if (r1 < r)
                r = r1;

        if (a->archive.state != ARCHIVE_STATE_FATAL)
                a->archive.state = ARCHIVE_STATE_CLOSED;
        return (r);
}

static int
_archive_write_filter_count(struct archive *_a)
{
        struct archive_write *a = (struct archive_write *)_a;
        struct archive_write_filter *p = a->filter_first;
        int count = 0;
        while(p) {
                count++;
                p = p->next_filter;
        }
        return count;
}

void
__archive_write_filters_free(struct archive *_a)
{
        struct archive_write *a = (struct archive_write *)_a;
        int r = ARCHIVE_OK, r1;

        while (a->filter_first != NULL) {
                struct archive_write_filter *next
                    = a->filter_first->next_filter;
                if (a->filter_first->free != NULL) {
                        r1 = (*a->filter_first->free)(a->filter_first);
                        if (r > r1)
                                r = r1;
                }
                free(a->filter_first);
                a->filter_first = next;
        }
        a->filter_last = NULL;
}

/*
 * Destroy the archive structure.
 *
 * Be careful: user might just call write_new and then write_free.
 * Don't assume we actually wrote anything or performed any non-trivial
 * initialization.
 */
static int
_archive_write_free(struct archive *_a)
{
        struct archive_write *a = (struct archive_write *)_a;
        int r = ARCHIVE_OK, r1;

        if (_a == NULL)
                return (ARCHIVE_OK);
        /* It is okay to call free() in state FATAL. */
        archive_check_magic(&a->archive, ARCHIVE_WRITE_MAGIC,
            ARCHIVE_STATE_ANY | ARCHIVE_STATE_FATAL, "archive_write_free");
        if (a->archive.state != ARCHIVE_STATE_FATAL)
                r = archive_write_close(&a->archive);

        /* Release format resources. */
        if (a->format_free != NULL) {
                r1 = (a->format_free)(a);
                if (r1 < r)
                        r = r1;
        }

        __archive_write_filters_free(_a);

        /* Release various dynamic buffers. */
        free((void *)(uintptr_t)(const void *)a->nulls);
        archive_string_free(&a->archive.error_string);
        if (a->passphrase != NULL) {
                /* A passphrase should be cleaned. */
                memset(a->passphrase, 0, strlen(a->passphrase));
                free(a->passphrase);
        }
        a->archive.magic = 0;
        __archive_clean(&a->archive);
        free(a);
        return (r);
}

/*
 * Write the appropriate header.
 */
static int
_archive_write_header(struct archive *_a, struct archive_entry *entry)
{
        struct archive_write *a = (struct archive_write *)_a;
        int ret, r2;

        archive_check_magic(&a->archive, ARCHIVE_WRITE_MAGIC,
            ARCHIVE_STATE_DATA | ARCHIVE_STATE_HEADER, "archive_write_header");
        archive_clear_error(&a->archive);

        if (a->format_write_header == NULL) {
                archive_set_error(&(a->archive), -1,
                    "Format must be set before you can write to an archive.");
                a->archive.state = ARCHIVE_STATE_FATAL;
                return (ARCHIVE_FATAL);
        }

        /* In particular, "retry" and "fatal" get returned immediately. */
        ret = archive_write_finish_entry(&a->archive);
        if (ret == ARCHIVE_FATAL) {
                a->archive.state = ARCHIVE_STATE_FATAL;
                return (ARCHIVE_FATAL);
        }
        if (ret < ARCHIVE_OK && ret != ARCHIVE_WARN)
                return (ret);

        if (a->skip_file_set &&
            archive_entry_dev_is_set(entry) &&
            archive_entry_ino_is_set(entry) &&
            archive_entry_dev(entry) == (dev_t)a->skip_file_dev &&
            archive_entry_ino64(entry) == a->skip_file_ino) {
                archive_set_error(&a->archive, 0,
                    "Can't add archive to itself");
                return (ARCHIVE_FAILED);
        }

        /* Format and write header. */
        r2 = ((a->format_write_header)(a, entry));
        if (r2 == ARCHIVE_FAILED) {
                return (ARCHIVE_FAILED);
        }
        if (r2 == ARCHIVE_FATAL) {
                a->archive.state = ARCHIVE_STATE_FATAL;
                return (ARCHIVE_FATAL);
        }
        if (r2 < ret)
                ret = r2;

        a->archive.state = ARCHIVE_STATE_DATA;
        return (ret);
}

static int
_archive_write_finish_entry(struct archive *_a)
{
        struct archive_write *a = (struct archive_write *)_a;
        int ret = ARCHIVE_OK;

        archive_check_magic(&a->archive, ARCHIVE_WRITE_MAGIC,
            ARCHIVE_STATE_HEADER | ARCHIVE_STATE_DATA,
            "archive_write_finish_entry");
        if (a->archive.state & ARCHIVE_STATE_DATA
            && a->format_finish_entry != NULL)
                ret = (a->format_finish_entry)(a);
        a->archive.state = ARCHIVE_STATE_HEADER;
        return (ret);
}

/*
 * Note that the compressor is responsible for blocking.
 */
static ssize_t
_archive_write_data(struct archive *_a, const void *buff, size_t s)
{
        struct archive_write *a = (struct archive_write *)_a;
        const size_t max_write = INT_MAX;

        archive_check_magic(&a->archive, ARCHIVE_WRITE_MAGIC,
            ARCHIVE_STATE_DATA, "archive_write_data");
        /* In particular, this catches attempts to pass negative values. */
        if (s > max_write)
                s = max_write;
        archive_clear_error(&a->archive);
        return ((a->format_write_data)(a, buff, s));
}

static struct archive_write_filter *
filter_lookup(struct archive *_a, int n)
{
        struct archive_write *a = (struct archive_write *)_a;
        struct archive_write_filter *f = a->filter_first;
        if (n == -1)
                return a->filter_last;
        if (n < 0)
                return NULL;
        while (n > 0 && f != NULL) {
                f = f->next_filter;
                --n;
        }
        return f;
}

static int
_archive_filter_code(struct archive *_a, int n)
{
        struct archive_write_filter *f = filter_lookup(_a, n);
        return f == NULL ? -1 : f->code;
}

static const char *
_archive_filter_name(struct archive *_a, int n)
{
        struct archive_write_filter *f = filter_lookup(_a, n);
        return f != NULL ? f->name : NULL;
}

static int64_t
_archive_filter_bytes(struct archive *_a, int n)
{
        struct archive_write_filter *f = filter_lookup(_a, n);
        return f == NULL ? -1 : f->bytes_written;
}