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hlink.c

Go to the documentation of this file.

/* 
   Copyright (C) Andrew Tridgell 1996
   Copyright (C) Paul Mackerras 1996
   Copyright (C) 2002 by Martin Pool <mbp@samba.org>
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "rsync.h"

extern int dry_run;
extern int verbose;

#if SUPPORT_HARD_LINKS
static int hlink_compare(struct file_struct *f1, struct file_struct *f2)
{
        if (!S_ISREG(f1->mode) && !S_ISREG(f2->mode))
                return 0;
        if (!S_ISREG(f1->mode))
                return -1;
        if (!S_ISREG(f2->mode))
                return 1;

        if (f1->dev != f2->dev)
                return (int) (f1->dev > f2->dev ? 1 : -1);

        if (f1->inode != f2->inode)
                return (int) (f1->inode > f2->inode ? 1 : -1);

        return file_compare(&f1, &f2);
}


static struct file_struct *hlink_list;
static int hlink_count;
#endif

void init_hard_links(struct file_list *flist)
{
#if SUPPORT_HARD_LINKS
        int i;
        if (flist->count < 2)
                return;

        if (hlink_list)
                free(hlink_list);

        if (!(hlink_list =
              (struct file_struct *) malloc(sizeof(hlink_list[0]) *
                                            flist->count)))
                out_of_memory("init_hard_links");

        for (i = 0; i < flist->count; i++)
                memcpy(&hlink_list[i], flist->files[i],
                       sizeof(hlink_list[0]));

        qsort(hlink_list, flist->count,
              sizeof(hlink_list[0]), (int (*)()) hlink_compare);

        hlink_count = flist->count;
#endif
}

/* check if a file should be skipped because it is the same as an
   earlier hard link */
int check_hard_link(struct file_struct *file)
{
#if SUPPORT_HARD_LINKS
        int low = 0, high = hlink_count - 1;
        int ret = 0;

        if (!hlink_list || !S_ISREG(file->mode))
                return 0;

        while (low != high) {
                int mid = (low + high) / 2;
                ret = hlink_compare(&hlink_list[mid], file);
                if (ret == 0) {
                        low = mid;
                        break;
                }
                if (ret > 0)
                        high = mid;
                else
                        low = mid + 1;
        }

        /* XXX: To me this looks kind of dodgy -- why do we use [low]
         * here and [low-1] below? -- mbp */
        if (hlink_compare(&hlink_list[low], file) != 0)
                return 0;

        if (low > 0 &&
            S_ISREG(hlink_list[low - 1].mode) &&
            file->dev == hlink_list[low - 1].dev &&
            file->inode == hlink_list[low - 1].inode) {
                if (verbose >= 2) {
                        rprintf(FINFO, "check_hard_link: \"%s\" is a hard link to file %d, \"%s\"\n",
                                f_name(file), low-1, f_name(&hlink_list[low-1]));
                }
                return 1;
        }
#endif

        return 0;
}


#if SUPPORT_HARD_LINKS
static void hard_link_one(int i)
{
        STRUCT_STAT st1, st2;

        if (link_stat(f_name(&hlink_list[i - 1]), &st1) != 0)
                return;

        if (link_stat(f_name(&hlink_list[i]), &st2) != 0) {
                if (do_link
                    (f_name(&hlink_list[i - 1]),
                     f_name(&hlink_list[i])) != 0) {
                        if (verbose > 0)
                                rprintf(FINFO, "link %s => %s : %s\n",
                                        f_name(&hlink_list[i]),
                                        f_name(&hlink_list[i - 1]),
                                        strerror(errno));
                        return;
                }
        } else {
                if (st2.st_dev == st1.st_dev && st2.st_ino == st1.st_ino)
                        return;

                if (robust_unlink(f_name(&hlink_list[i])) != 0 ||
                    do_link(f_name(&hlink_list[i - 1]),
                            f_name(&hlink_list[i])) != 0) {
                        if (verbose > 0)
                                rprintf(FINFO, "link %s => %s : %s\n",
                                        f_name(&hlink_list[i]),
                                        f_name(&hlink_list[i - 1]),
                                        strerror(errno));
                        return;
                }
        }
        if (verbose > 0)
                rprintf(FINFO, "%s => %s\n",
                        f_name(&hlink_list[i]),
                        f_name(&hlink_list[i - 1]));
}
#endif



/**
 * Create any hard links in the global hlink_list.  They were put
 * there by running init_hard_links on the filelist.
 **/
void do_hard_links(void)
{
#if SUPPORT_HARD_LINKS
        int i;

        if (!hlink_list)
                return;

        for (i = 1; i < hlink_count; i++) {
                if (S_ISREG(hlink_list[i].mode) &&
                    S_ISREG(hlink_list[i - 1].mode) &&
                    hlink_list[i].basename && hlink_list[i - 1].basename &&
                    hlink_list[i].dev == hlink_list[i - 1].dev &&
                    hlink_list[i].inode == hlink_list[i - 1].inode) {
                        hard_link_one(i);
                }
        }
#endif
}

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