cmd/cpio/utils.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*  Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */
/*  All Rights Reserved                 */

/*
 * Portions of this source code were derived from Berkeley 4.3 BSD
 * under license from the Regents of the University of California.
 */

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
#include <ctype.h>
#include <limits.h>
#include <errno.h>
#include <fcntl.h>

#include "cpio.h"

/*
 * Allocation wrappers.  Used to centralize error handling for
 * failed allocations.
 */
static void *
e_alloc_fail(int flag)
{
    if (flag == E_EXIT)
        msg(EXTN, "Out of memory");

    return (NULL);
}

/*
 *  Note: unlike the other e_*lloc functions, e_realloc does not zero out the
 *  additional memory it returns.  Ensure that you do not trust its contents
 *  when you call it.
 */
void *
e_realloc(int flag, void *old, size_t newsize)
{
    void *ret = realloc(old, newsize);

    if (ret == NULL) {
        return (e_alloc_fail(flag));
    }

    return (ret);
}

char *
e_strdup(int flag, const char *arg)
{
    char *ret = strdup(arg);

    if (ret == NULL) {
        return (e_alloc_fail(flag));
    }

    return (ret);
}

void *
e_valloc(int flag, size_t size)
{
    void *ret = valloc(size);

    if (ret == NULL) {
        return (e_alloc_fail(flag));
    }

    return (ret);
}

void *
e_zalloc(int flag, size_t size)
{
    void *ret = malloc(size);

    if (ret == NULL) {
        return (e_alloc_fail(flag));
    }

    (void) memset(ret, 0, size);
    return (ret);
}

/*
 * Simple printf() which only support "%s" conversion.
 * We need secure version of printf since format string can be supplied
 * from gettext().
 */
void
str_fprintf(FILE *fp, const char *fmt, ...)
{
    const char *s = fmt;
    va_list ap;

    va_start(ap, fmt);
    while (*s != '\0') {
        if (*s != '%') {
            (void) fputc(*s++, fp);
            continue;
        }
        s++;
        if (*s != 's') {
            (void) fputc(*(s - 1), fp);
            (void) fputc(*s++, fp);
            continue;
        }
        (void) fputs(va_arg(ap, char *), fp);
        s++;
    }
    va_end(ap);
}

/*
 * Step through a file discovering and recording pairs of data and hole
 * offsets. Returns a linked list of data/hole offset pairs of a file.
 * If there is no holes found, NULL is returned.
 *
 * Note: According to lseek(2), only filesystems which support
 * fpathconf(_PC_MIN_HOLE_SIZE) support SEEK_HOLE.  For filesystems
 * that do not supply information about holes, the file will be
 * represented as one entire data region.
 */
static holes_list_t *
get_holes_list(int fd, off_t filesz, size_t *countp)
{
    off_t   data, hole;
    holes_list_t *hlh, *hl, **hlp;
    size_t  cnt;

    if (filesz == 0 || fpathconf(fd, _PC_MIN_HOLE_SIZE) < 0)
        return (NULL);

    cnt = 0;
    hole = 0;
    hlh = NULL;
    hlp = &hlh;

    while (hole < filesz) {
        if ((data = lseek(fd, hole, SEEK_DATA)) == -1) {
            /* no more data till the end of file */
            if (errno == ENXIO) {
                data = filesz;
            } else {
                /* assume data starts from the * beginning */
                data = 0;
            }
        }
        if ((hole = lseek(fd, data, SEEK_HOLE)) == -1) {
            /* assume that data ends at the end of file */
            hole = filesz;
        }
        if (data == 0 && hole == filesz) {
            /* no holes */
            break;
        }
        hl = e_zalloc(E_EXIT, sizeof (holes_list_t));
        hl->hl_next = NULL;

        /* set data and hole */
        hl->hl_data = data;
        hl->hl_hole = hole;

        *hlp = hl;
        hlp = &hl->hl_next;
        cnt++;
    }
    if (countp != NULL)
        *countp = cnt;

    /*
     * reset to the beginning, otherwise subsequent read calls would
     * get EOF
     */
    (void) lseek(fd, 0, SEEK_SET);

    return (hlh);
}

/*
 * Calculate the real data size in the sparse file.
 */
static off_t
get_compressed_filesz(holes_list_t *hlh)
{
    holes_list_t *hl;
    off_t   size;

    size = 0;
    for (hl = hlh; hl != NULL; hl = hl->hl_next) {
        size += (hl->hl_hole - hl->hl_data);
    }
    return (size);
}

/*
 * Convert val to digit string and put it in str. The next address
 * of the last digit is returned.
 */
static char *
put_value(off_t val, char *str)
{
    size_t  len;
    char    *digp, dbuf[ULL_MAX_SIZE + 1];

    dbuf[ULL_MAX_SIZE] = '\0';
    digp = ulltostr((u_longlong_t)val, &dbuf[ULL_MAX_SIZE]);
    len = &dbuf[ULL_MAX_SIZE] - digp;
    (void) memcpy(str, digp, len);

    return (str + len);
}

/*
 * Put data/hole offset pair into string in the following
 * sequence.
 * <data> <sp> <hole> <sp>
 */
static void
store_sparse_string(holes_list_t *hlh, char *str, size_t *szp)
{
    holes_list_t *hl;
    char    *p;

    p = str;
    for (hl = hlh; hl != NULL; hl = hl->hl_next) {
        p = put_value(hl->hl_data, p);
        *p++ = ' ';
        p = put_value(hl->hl_hole, p);
        *p++ = ' ';
    }
    *--p = '\0';
    if (szp != NULL)
        *szp = p - str;
}

/*
 * Convert decimal str into unsigned long long value. The end pointer
 * is returned.
 */
static const char *
get_ull_tok(const char *str, uint64_t *ulp)
{
    uint64_t ul;
    char    *np;

    while (isspace(*str))
        str++;
    if (!isdigit(*str))
        return (NULL);

    errno = 0;
    ul = strtoull(str, &np, 10);
    if (ul == ULLONG_MAX && errno == ERANGE)
        return (NULL);      /* invalid value */
    if (*np != ' ' && *np != '\0')
        return (NULL);      /* invalid input */

    *ulp = ul;
    return (np);
}

static void
free_holesdata(holes_info_t *hi)
{
    holes_list_t    *hl, *nhl;

    for (hl = hi->holes_list; hl != NULL; hl = nhl) {
        nhl = hl->hl_next;
        free(hl);
    }
    hi->holes_list = NULL;

    if (hi->holesdata != NULL)
        free(hi->holesdata);
    hi->holesdata = NULL;
}

/*
 * When a hole is detected, non NULL holes_info pointer is returned.
 * If we are in copy-out mode, holes_list is converted to string (holesdata)
 * which will be prepended to file contents. The holesdata is a character
 * string and in the format of:
 *
 * <data size(%10u)><SP><file size(%llu)><SP>
 *   <SP><data off><SP><hole off><SP><data off><SP><hole off> ...
 *
 * This string is parsed by parse_holesholes() in copy-in mode to restore
 * the sparse info.
 */
holes_info_t *
get_holes_info(int fd, off_t filesz, boolean_t pass_mode)
{
    holes_info_t *hi;
    holes_list_t *hl;
    char    *str, hstr[MIN_HOLES_HDRSIZE + 1];
    size_t  ninfo, len;

    if ((hl = get_holes_list(fd, filesz, &ninfo)) == NULL)
        return (NULL);

    hi = e_zalloc(E_EXIT, sizeof (holes_info_t));
    hi->holes_list = hl;

    if (!pass_mode) {
        str = e_zalloc(E_EXIT,
            MIN_HOLES_HDRSIZE + ninfo * (ULL_MAX_SIZE * 2));
        /*
         * Convert into string data, and place it to after
         * the first 2 fixed entries.
         */
        store_sparse_string(hl, str + MIN_HOLES_HDRSIZE, &len);

        /*
         * Add the first two fixed entries. The size of holesdata
         * includes '\0' at the end of data
         */
        (void) sprintf(hstr, "%10lu %20llu ",
            (ulong_t)MIN_HOLES_HDRSIZE + len + 1, filesz);
        (void) memcpy(str, hstr, MIN_HOLES_HDRSIZE);

        /* calc real file size without holes */
        hi->data_size = get_compressed_filesz(hl);
        hi->holesdata = str;
        hi->holesdata_sz = MIN_HOLES_HDRSIZE + len + 1;
    }
    return (hi);
}

/*
 * The holesdata information is in the following format:
 * <data size(%10u)><SP><file size(%llu)><SP>
 *   <SP><data off><SP><hole off><SP><data off><SP><hole off> ...
 * read_holes_header() allocates holes_info_t, and read the first 2
 * entries (data size and file size). The rest of holesdata is
 * read by parse_holesdata().
 */
holes_info_t *
read_holes_header(const char *str, off_t filesz)
{
    holes_info_t    *hi;
    uint64_t    ull;

    hi = e_zalloc(E_EXIT, sizeof (holes_info_t));

    /* read prepended holes data size */
    if ((str = get_ull_tok(str, &ull)) == NULL || *str != ' ') {
bad:
        free(hi);
        return (NULL);
    }
    hi->holesdata_sz = (size_t)ull;

    /* read original(expanded) file size */
    if (get_ull_tok(str, &ull) == NULL)
        goto bad;
    hi->orig_size = (off_t)ull;

    /* sanity check */
    if (hi->holesdata_sz > filesz ||
        hi->holesdata_sz <= MIN_HOLES_HDRSIZE) {
        goto bad;
    }
    return (hi);
}

int
parse_holesdata(holes_info_t *hi, const char *str)
{
    holes_list_t    *hl, **hlp;
    uint64_t    ull;
    off_t       loff;

    /* create hole list */
    hlp = &hi->holes_list;
    while (*str != '\0') {
        hl = e_zalloc(E_EXIT, sizeof (holes_list_t));
        /* link list */
        hl->hl_next = NULL;
        *hlp = hl;
        hlp = &hl->hl_next;

        /* read the string token for data */
        if ((str = get_ull_tok(str, &ull)) == NULL)
            goto bad;
        hl->hl_data = (off_t)ull;

        /* there must be single blank space in between */
        if (*str != ' ')
            goto bad;

        /* read the string token for hole */
        if ((str = get_ull_tok(str, &ull)) == NULL)
            goto bad;
        hl->hl_hole = (off_t)ull;
    }

    /* check to see if offset is in ascending order */
    loff = -1;
    for (hl = hi->holes_list; hl != NULL; hl = hl->hl_next) {
        if (loff >= hl->hl_data)
            goto bad;
        loff = hl->hl_data;
        /* data and hole can be equal */
        if (loff > hl->hl_hole)
            goto bad;
        loff = hl->hl_hole;
    }
    /* The last hole offset should match original file size */
    if (hi->orig_size != loff) {
bad:
        free_holesdata(hi);
        return (1);
    }

    hi->data_size = get_compressed_filesz(hi->holes_list);

    return (0);
}

void
free_holes_info(holes_info_t *hi)
{
    free_holesdata(hi);
    free(hi);
}