/*-
 * Copyright (c) 2003-2007 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: src/lib/libarchive/archive_read_support_format_cpio.c,v 1.27 2008/12/06 06:45:15 kientzle Exp $");

#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
/* #include <stdint.h> */ /* See archive_platform.h */
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif

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

struct cpio_bin_header {
    unsigned char   c_magic[2];
    unsigned char   c_dev[2];
    unsigned char   c_ino[2];
    unsigned char   c_mode[2];
    unsigned char   c_uid[2];
    unsigned char   c_gid[2];
    unsigned char   c_nlink[2];
    unsigned char   c_rdev[2];
    unsigned char   c_mtime[4];
    unsigned char   c_namesize[2];
    unsigned char   c_filesize[4];
};

struct cpio_odc_header {
    char    c_magic[6];
    char    c_dev[6];
    char    c_ino[6];
    char    c_mode[6];
    char    c_uid[6];
    char    c_gid[6];
    char    c_nlink[6];
    char    c_rdev[6];
    char    c_mtime[11];
    char    c_namesize[6];
    char    c_filesize[11];
};

struct cpio_newc_header {
    char    c_magic[6];
    char    c_ino[8];
    char    c_mode[8];
    char    c_uid[8];
    char    c_gid[8];
    char    c_nlink[8];
    char    c_mtime[8];
    char    c_filesize[8];
    char    c_devmajor[8];
    char    c_devminor[8];
    char    c_rdevmajor[8];
    char    c_rdevminor[8];
    char    c_namesize[8];
    char    c_crc[8];
};

struct links_entry {
        struct links_entry      *next;
        struct links_entry      *previous;
        int                      links;
        dev_t                    dev;
        int64_t                  ino;
        char                    *name;
};

#define CPIO_MAGIC   0x13141516
struct cpio {
    int           magic;
    int         (*read_header)(struct archive_read *, struct cpio *,
                     struct archive_entry *, size_t *, size_t *);
    struct links_entry   *links_head;
    struct archive_string     entry_name;
    struct archive_string     entry_linkname;
    off_t             entry_bytes_remaining;
    off_t             entry_offset;
    off_t             entry_padding;
};

static int64_t  atol16(const char *, unsigned);
static int64_t  atol8(const char *, unsigned);
static int  archive_read_format_cpio_bid(struct archive_read *);
static int  archive_read_format_cpio_cleanup(struct archive_read *);
static int  archive_read_format_cpio_read_data(struct archive_read *,
            const void **, size_t *, off_t *);
static int  archive_read_format_cpio_read_header(struct archive_read *,
            struct archive_entry *);
static int  be4(const unsigned char *);
static int  find_odc_header(struct archive_read *);
static int  find_newc_header(struct archive_read *);
static int  header_bin_be(struct archive_read *, struct cpio *,
            struct archive_entry *, size_t *, size_t *);
static int  header_bin_le(struct archive_read *, struct cpio *,
            struct archive_entry *, size_t *, size_t *);
static int  header_newc(struct archive_read *, struct cpio *,
            struct archive_entry *, size_t *, size_t *);
static int  header_odc(struct archive_read *, struct cpio *,
            struct archive_entry *, size_t *, size_t *);
static int  is_octal(const char *, size_t);
static int  is_hex(const char *, size_t);
static int  le4(const unsigned char *);
static void record_hardlink(struct cpio *cpio, struct archive_entry *entry);

int
archive_read_support_format_cpio(struct archive *_a)
{
    struct archive_read *a = (struct archive_read *)_a;
    struct cpio *cpio;
    int r;

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

    r = __archive_read_register_format(a,
        cpio,
        "cpio",
        archive_read_format_cpio_bid,
        NULL,
        archive_read_format_cpio_read_header,
        archive_read_format_cpio_read_data,
        NULL,
        archive_read_format_cpio_cleanup);

    if (r != ARCHIVE_OK)
        free(cpio);
    return (ARCHIVE_OK);
}


static int
archive_read_format_cpio_bid(struct archive_read *a)
{
    const void *h;
    const unsigned char *p;
    struct cpio *cpio;
    int bid;

    cpio = (struct cpio *)(a->format->data);

    if ((h = __archive_read_ahead(a, 6, NULL)) == NULL)
        return (-1);

    p = (const unsigned char *)h;
    bid = 0;
    if (memcmp(p, "070707", 6) == 0) {
        /* ASCII cpio archive (odc, POSIX.1) */
        cpio->read_header = header_odc;
        bid += 48;
        /*
         * XXX TODO:  More verification; Could check that only octal
         * digits appear in appropriate header locations. XXX
         */
    } else if (memcmp(p, "070701", 6) == 0) {
        /* ASCII cpio archive (SVR4 without CRC) */
        cpio->read_header = header_newc;
        bid += 48;
        /*
         * XXX TODO:  More verification; Could check that only hex
         * digits appear in appropriate header locations. XXX
         */
    } else if (memcmp(p, "070702", 6) == 0) {
        /* ASCII cpio archive (SVR4 with CRC) */
        /* XXX TODO: Flag that we should check the CRC. XXX */
        cpio->read_header = header_newc;
        bid += 48;
        /*
         * XXX TODO:  More verification; Could check that only hex
         * digits appear in appropriate header locations. XXX
         */
    } else if (p[0] * 256 + p[1] == 070707) {
        /* big-endian binary cpio archives */
        cpio->read_header = header_bin_be;
        bid += 16;
        /* Is more verification possible here? */
    } else if (p[0] + p[1] * 256 == 070707) {
        /* little-endian binary cpio archives */
        cpio->read_header = header_bin_le;
        bid += 16;
        /* Is more verification possible here? */
    } else
        return (ARCHIVE_WARN);

    return (bid);
}

static int
archive_read_format_cpio_read_header(struct archive_read *a,
    struct archive_entry *entry)
{
    struct cpio *cpio;
    const void *h;
    size_t namelength;
    size_t name_pad;
    int r;

    cpio = (struct cpio *)(a->format->data);
    r = (cpio->read_header(a, cpio, entry, &namelength, &name_pad));

    if (r < ARCHIVE_WARN)
        return (r);

    /* Read name from buffer. */
    h = __archive_read_ahead(a, namelength + name_pad, NULL);
    if (h == NULL)
        return (ARCHIVE_FATAL);
    __archive_read_consume(a, namelength + name_pad);
    archive_strncpy(&cpio->entry_name, (const char *)h, namelength);
    archive_entry_set_pathname(entry, cpio->entry_name.s);
    cpio->entry_offset = 0;

    /* If this is a symlink, read the link contents. */
    if (archive_entry_filetype(entry) == AE_IFLNK) {
        h = __archive_read_ahead(a, cpio->entry_bytes_remaining, NULL);
        if (h == NULL)
            return (ARCHIVE_FATAL);
        __archive_read_consume(a, cpio->entry_bytes_remaining);
        archive_strncpy(&cpio->entry_linkname, (const char *)h,
            cpio->entry_bytes_remaining);
        archive_entry_set_symlink(entry, cpio->entry_linkname.s);
        cpio->entry_bytes_remaining = 0;
    }

    /* XXX TODO: If the full mode is 0160200, then this is a Solaris
     * ACL description for the following entry.  Read this body
     * and parse it as a Solaris-style ACL, then read the next
     * header.  XXX */

    /* Compare name to "TRAILER!!!" to test for end-of-archive. */
    if (namelength == 11 && strcmp((const char *)h, "TRAILER!!!") == 0) {
        /* TODO: Store file location of start of block. */
        archive_set_error(&a->archive, 0, NULL);
        return (ARCHIVE_EOF);
    }

    /* Detect and record hardlinks to previously-extracted entries. */
    record_hardlink(cpio, entry);

    return (r);
}

static int
archive_read_format_cpio_read_data(struct archive_read *a,
    const void **buff, size_t *size, off_t *offset)
{
    ssize_t bytes_read;
    struct cpio *cpio;

    cpio = (struct cpio *)(a->format->data);
    if (cpio->entry_bytes_remaining > 0) {
        *buff = __archive_read_ahead(a, 1, &bytes_read);
        if (bytes_read <= 0)
            return (ARCHIVE_FATAL);
        if (bytes_read > cpio->entry_bytes_remaining)
            bytes_read = cpio->entry_bytes_remaining;
        *size = bytes_read;
        *offset = cpio->entry_offset;
        cpio->entry_offset += bytes_read;
        cpio->entry_bytes_remaining -= bytes_read;
        __archive_read_consume(a, bytes_read);
        return (ARCHIVE_OK);
    } else {
        while (cpio->entry_padding > 0) {
            *buff = __archive_read_ahead(a, 1, &bytes_read);
            if (bytes_read <= 0)
                return (ARCHIVE_FATAL);
            if (bytes_read > cpio->entry_padding)
                bytes_read = cpio->entry_padding;
            __archive_read_consume(a, bytes_read);
            cpio->entry_padding -= bytes_read;
        }
        *buff = NULL;
        *size = 0;
        *offset = cpio->entry_offset;
        return (ARCHIVE_EOF);
    }
}

/*
 * Skip forward to the next cpio newc header by searching for the
 * 07070[12] string.  This should be generalized and merged with
 * find_odc_header below.
 */
static int
is_hex(const char *p, size_t len)
{
    while (len-- > 0) {
        if ((*p >= '0' && *p <= '9')
            || (*p >= 'a' && *p <= 'f')
            || (*p >= 'A' && *p <= 'F'))
            ++p;
        else
            return (0);
    }
    return (1);
}

static int
find_newc_header(struct archive_read *a)
{
    const void *h;
    const char *p, *q;
    size_t skip, skipped = 0;
    ssize_t bytes;

    for (;;) {
        h = __archive_read_ahead(a, sizeof(struct cpio_newc_header), &bytes);
        if (h == NULL)
            return (ARCHIVE_FATAL);
        p = h;
        q = p + bytes;

        /* Try the typical case first, then go into the slow search.*/
        if (memcmp("07070", p, 5) == 0
            && (p[5] == '1' || p[5] == '2')
            && is_hex(p, sizeof(struct cpio_newc_header)))
            return (ARCHIVE_OK);

        /*
         * Scan ahead until we find something that looks
         * like an odc header.
         */
        while (p + sizeof(struct cpio_newc_header) < q) {
            switch (p[5]) {
            case '1':
            case '2':
                if (memcmp("07070", p, 5) == 0
                    && is_hex(p, sizeof(struct cpio_newc_header))) {
                    skip = p - (const char *)h;
                    __archive_read_consume(a, skip);
                    skipped += skip;
                    if (skipped > 0) {
                        archive_set_error(&a->archive,
                            0,
                            "Skipped %d bytes before "
                            "finding valid header",
                            (int)skipped);
                        return (ARCHIVE_WARN);
                    }
                    return (ARCHIVE_OK);
                }
                p += 2;
                break;
            case '0':
                p++;
                break;
            default:
                p += 6;
                break;
            }
        }
        skip = p - (const char *)h;
        __archive_read_consume(a, skip);
        skipped += skip;
    }
}

static int
header_newc(struct archive_read *a, struct cpio *cpio,
    struct archive_entry *entry, size_t *namelength, size_t *name_pad)
{
    const void *h;
    const struct cpio_newc_header *header;
    int r;

    r = find_newc_header(a);
    if (r < ARCHIVE_WARN)
        return (r);

    /* Read fixed-size portion of header. */
    h = __archive_read_ahead(a, sizeof(struct cpio_newc_header), NULL);
    if (h == NULL)
        return (ARCHIVE_FATAL);
    __archive_read_consume(a, sizeof(struct cpio_newc_header));

    /* Parse out hex fields. */
    header = (const struct cpio_newc_header *)h;

    if (memcmp(header->c_magic, "070701", 6) == 0) {
        a->archive.archive_format = ARCHIVE_FORMAT_CPIO_SVR4_NOCRC;
        a->archive.archive_format_name = "ASCII cpio (SVR4 with no CRC)";
    } else if (memcmp(header->c_magic, "070702", 6) == 0) {
        a->archive.archive_format = ARCHIVE_FORMAT_CPIO_SVR4_CRC;
        a->archive.archive_format_name = "ASCII cpio (SVR4 with CRC)";
    } else {
        /* TODO: Abort here? */
    }

    archive_entry_set_devmajor(entry, atol16(header->c_devmajor, sizeof(header->c_devmajor)));
    archive_entry_set_devminor(entry, atol16(header->c_devminor, sizeof(header->c_devminor)));
    archive_entry_set_ino(entry, atol16(header->c_ino, sizeof(header->c_ino)));
    archive_entry_set_mode(entry, atol16(header->c_mode, sizeof(header->c_mode)));
    archive_entry_set_uid(entry, atol16(header->c_uid, sizeof(header->c_uid)));
    archive_entry_set_gid(entry, atol16(header->c_gid, sizeof(header->c_gid)));
    archive_entry_set_nlink(entry, atol16(header->c_nlink, sizeof(header->c_nlink)));
    archive_entry_set_rdevmajor(entry, atol16(header->c_rdevmajor, sizeof(header->c_rdevmajor)));
    archive_entry_set_rdevminor(entry, atol16(header->c_rdevminor, sizeof(header->c_rdevminor)));
    archive_entry_set_mtime(entry, atol16(header->c_mtime, sizeof(header->c_mtime)), 0);
    *namelength = atol16(header->c_namesize, sizeof(header->c_namesize));
    /* Pad name to 2 more than a multiple of 4. */
    *name_pad = (2 - *namelength) & 3;

    /*
     * Note: entry_bytes_remaining is at least 64 bits and
     * therefore guaranteed to be big enough for a 33-bit file
     * size.
     */
    cpio->entry_bytes_remaining =
        atol16(header->c_filesize, sizeof(header->c_filesize));
    archive_entry_set_size(entry, cpio->entry_bytes_remaining);
    /* Pad file contents to a multiple of 4. */
    cpio->entry_padding = 3 & -cpio->entry_bytes_remaining;
    return (r);
}

/*
 * Skip forward to the next cpio odc header by searching for the
 * 070707 string.  This is a hand-optimized search that could
 * probably be easily generalized to handle all character-based
 * cpio variants.
 */
static int
is_octal(const char *p, size_t len)
{
    while (len-- > 0) {
        if (*p < '0' || *p > '7')
            return (0);
            ++p;
    }
    return (1);
}

static int
find_odc_header(struct archive_read *a)
{
    const void *h;
    const char *p, *q;
    size_t skip, skipped = 0;
    ssize_t bytes;

    for (;;) {
        h = __archive_read_ahead(a, sizeof(struct cpio_odc_header), &bytes);
        if (h == NULL)
            return (ARCHIVE_FATAL);
        p = h;
        q = p + bytes;

        /* Try the typical case first, then go into the slow search.*/
        if (memcmp("070707", p, 6) == 0
            && is_octal(p, sizeof(struct cpio_odc_header)))
            return (ARCHIVE_OK);

        /*
         * Scan ahead until we find something that looks
         * like an odc header.
         */
        while (p + sizeof(struct cpio_odc_header) < q) {
            switch (p[5]) {
            case '7':
                if (memcmp("070707", p, 6) == 0
                    && is_octal(p, sizeof(struct cpio_odc_header))) {
                    skip = p - (const char *)h;
                    __archive_read_consume(a, skip);
                    skipped += skip;
                    if (skipped > 0) {
                        archive_set_error(&a->archive,
                            0,
                            "Skipped %d bytes before "
                            "finding valid header",
                            (int)skipped);
                        return (ARCHIVE_WARN);
                    }
                    return (ARCHIVE_OK);
                }
                p += 2;
                break;
            case '0':
                p++;
                break;
            default:
                p += 6;
                break;
            }
        }
        skip = p - (const char *)h;
        __archive_read_consume(a, skip);
        skipped += skip;
    }
}

static int
header_odc(struct archive_read *a, struct cpio *cpio,
    struct archive_entry *entry, size_t *namelength, size_t *name_pad)
{
    const void *h;
    int r;
    const struct cpio_odc_header *header;

    a->archive.archive_format = ARCHIVE_FORMAT_CPIO_POSIX;
    a->archive.archive_format_name = "POSIX octet-oriented cpio";

    /* Find the start of the next header. */
    r = find_odc_header(a);
    if (r < ARCHIVE_WARN)
        return (r);

    /* Read fixed-size portion of header. */
    h = __archive_read_ahead(a, sizeof(struct cpio_odc_header), NULL);
    if (h == NULL)
        return (ARCHIVE_FATAL);
    __archive_read_consume(a, sizeof(struct cpio_odc_header));

    /* Parse out octal fields. */
    header = (const struct cpio_odc_header *)h;

    archive_entry_set_dev(entry, atol8(header->c_dev, sizeof(header->c_dev)));
    archive_entry_set_ino(entry, atol8(header->c_ino, sizeof(header->c_ino)));
    archive_entry_set_mode(entry, atol8(header->c_mode, sizeof(header->c_mode)));
    archive_entry_set_uid(entry, atol8(header->c_uid, sizeof(header->c_uid)));
    archive_entry_set_gid(entry, atol8(header->c_gid, sizeof(header->c_gid)));
    archive_entry_set_nlink(entry, atol8(header->c_nlink, sizeof(header->c_nlink)));
    archive_entry_set_rdev(entry, atol8(header->c_rdev, sizeof(header->c_rdev)));
    archive_entry_set_mtime(entry, atol8(header->c_mtime, sizeof(header->c_mtime)), 0);
    *namelength = atol8(header->c_namesize, sizeof(header->c_namesize));
    *name_pad = 0; /* No padding of filename. */

    /*
     * Note: entry_bytes_remaining is at least 64 bits and
     * therefore guaranteed to be big enough for a 33-bit file
     * size.
     */
    cpio->entry_bytes_remaining =
        atol8(header->c_filesize, sizeof(header->c_filesize));
    archive_entry_set_size(entry, cpio->entry_bytes_remaining);
    cpio->entry_padding = 0;
    return (r);
}

static int
header_bin_le(struct archive_read *a, struct cpio *cpio,
    struct archive_entry *entry, size_t *namelength, size_t *name_pad)
{
    const void *h;
    const struct cpio_bin_header *header;

    a->archive.archive_format = ARCHIVE_FORMAT_CPIO_BIN_LE;
    a->archive.archive_format_name = "cpio (little-endian binary)";

    /* Read fixed-size portion of header. */
    h = __archive_read_ahead(a, sizeof(struct cpio_bin_header), NULL);
    if (h == NULL)
        return (ARCHIVE_FATAL);
    __archive_read_consume(a, sizeof(struct cpio_bin_header));

    /* Parse out binary fields. */
    header = (const struct cpio_bin_header *)h;

    archive_entry_set_dev(entry, header->c_dev[0] + header->c_dev[1] * 256);
    archive_entry_set_ino(entry, header->c_ino[0] + header->c_ino[1] * 256);
    archive_entry_set_mode(entry, header->c_mode[0] + header->c_mode[1] * 256);
    archive_entry_set_uid(entry, header->c_uid[0] + header->c_uid[1] * 256);
    archive_entry_set_gid(entry, header->c_gid[0] + header->c_gid[1] * 256);
    archive_entry_set_nlink(entry, header->c_nlink[0] + header->c_nlink[1] * 256);
    archive_entry_set_rdev(entry, header->c_rdev[0] + header->c_rdev[1] * 256);
    archive_entry_set_mtime(entry, le4(header->c_mtime), 0);
    *namelength = header->c_namesize[0] + header->c_namesize[1] * 256;
    *name_pad = *namelength & 1; /* Pad to even. */

    cpio->entry_bytes_remaining = le4(header->c_filesize);
    archive_entry_set_size(entry, cpio->entry_bytes_remaining);
    cpio->entry_padding = cpio->entry_bytes_remaining & 1; /* Pad to even. */
    return (ARCHIVE_OK);
}

static int
header_bin_be(struct archive_read *a, struct cpio *cpio,
    struct archive_entry *entry, size_t *namelength, size_t *name_pad)
{
    const void *h;
    const struct cpio_bin_header *header;

    a->archive.archive_format = ARCHIVE_FORMAT_CPIO_BIN_BE;
    a->archive.archive_format_name = "cpio (big-endian binary)";

    /* Read fixed-size portion of header. */
    h = __archive_read_ahead(a, sizeof(struct cpio_bin_header), NULL);
    if (h == NULL)
        return (ARCHIVE_FATAL);
    __archive_read_consume(a, sizeof(struct cpio_bin_header));

    /* Parse out binary fields. */
    header = (const struct cpio_bin_header *)h;
    archive_entry_set_dev(entry, header->c_dev[0] * 256 + header->c_dev[1]);
    archive_entry_set_ino(entry, header->c_ino[0] * 256 + header->c_ino[1]);
    archive_entry_set_mode(entry, header->c_mode[0] * 256 + header->c_mode[1]);
    archive_entry_set_uid(entry, header->c_uid[0] * 256 + header->c_uid[1]);
    archive_entry_set_gid(entry, header->c_gid[0] * 256 + header->c_gid[1]);
    archive_entry_set_nlink(entry, header->c_nlink[0] * 256 + header->c_nlink[1]);
    archive_entry_set_rdev(entry, header->c_rdev[0] * 256 + header->c_rdev[1]);
    archive_entry_set_mtime(entry, be4(header->c_mtime), 0);
    *namelength = header->c_namesize[0] * 256 + header->c_namesize[1];
    *name_pad = *namelength & 1; /* Pad to even. */

    cpio->entry_bytes_remaining = be4(header->c_filesize);
    archive_entry_set_size(entry, cpio->entry_bytes_remaining);
    cpio->entry_padding = cpio->entry_bytes_remaining & 1; /* Pad to even. */
    return (ARCHIVE_OK);
}

static int
archive_read_format_cpio_cleanup(struct archive_read *a)
{
    struct cpio *cpio;

    cpio = (struct cpio *)(a->format->data);
        /* Free inode->name map */
        while (cpio->links_head != NULL) {
                struct links_entry *lp = cpio->links_head->next;

                if (cpio->links_head->name)
                        free(cpio->links_head->name);
                free(cpio->links_head);
                cpio->links_head = lp;
        }
    archive_string_free(&cpio->entry_name);
    free(cpio);
    (a->format->data) = NULL;
    return (ARCHIVE_OK);
}

static int
le4(const unsigned char *p)
{
    return ((p[0]<<16) + (p[1]<<24) + (p[2]<<0) + (p[3]<<8));
}


static int
be4(const unsigned char *p)
{
    return ((p[0]<<24) + (p[1]<<16) + (p[2]<<8) + (p[3]));
}

/*
 * Note that this implementation does not (and should not!) obey
 * locale settings; you cannot simply substitute strtol here, since
 * it does obey locale.
 */
static int64_t
atol8(const char *p, unsigned char_cnt)
{
    int64_t l;
    int digit;

    l = 0;
    while (char_cnt-- > 0) {
        if (*p >= '0' && *p <= '7')
            digit = *p - '0';
        else
            return (l);
        p++;
        l <<= 3;
        l |= digit;
    }
    return (l);
}

static int64_t
atol16(const char *p, unsigned char_cnt)
{
    int64_t l;
    int digit;

    l = 0;
    while (char_cnt-- > 0) {
        if (*p >= 'a' && *p <= 'f')
            digit = *p - 'a' + 10;
        else if (*p >= 'A' && *p <= 'F')
            digit = *p - 'A' + 10;
        else if (*p >= '0' && *p <= '9')
            digit = *p - '0';
        else
            return (l);
        p++;
        l <<= 4;
        l |= digit;
    }
    return (l);
}

static void
record_hardlink(struct cpio *cpio, struct archive_entry *entry)
{
    struct links_entry      *le;
    dev_t dev;
    int64_t ino;

    dev = archive_entry_dev(entry);
    ino = archive_entry_ino64(entry);

    /*
     * First look in the list of multiply-linked files.  If we've
     * already dumped it, convert this entry to a hard link entry.
     */
    for (le = cpio->links_head; le; le = le->next) {
        if (le->dev == dev && le->ino == ino) {
            archive_entry_copy_hardlink(entry, le->name);

            if (--le->links <= 0) {
                if (le->previous != NULL)
                    le->previous->next = le->next;
                if (le->next != NULL)
                    le->next->previous = le->previous;
                if (cpio->links_head == le)
                    cpio->links_head = le->next;
                free(le->name);
                free(le);
            }

            return;
        }
    }

    le = (struct links_entry *)malloc(sizeof(struct links_entry));
    if (le == NULL)
        __archive_errx(1, "Out of memory adding file to list");
    if (cpio->links_head != NULL)
        cpio->links_head->previous = le;
    le->next = cpio->links_head;
    le->previous = NULL;
    cpio->links_head = le;
    le->dev = dev;
    le->ino = ino;
    le->links = archive_entry_nlink(entry) - 1;
    le->name = strdup(archive_entry_pathname(entry));
    if (le->name == NULL)
        __archive_errx(1, "Out of memory adding file to list");
}
