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/* Unlink files.
Copyright 2009, 2013-2014, 2016 Free Software Foundation, Inc.
This file is part of GNU tar.
GNU tar 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 3 of the License, or
(at your option) any later version.
GNU tar 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, see <http://www.gnu.org/licenses/>. */
#include <system.h>
#include "common.h"
#include <quotearg.h>
struct deferred_unlink
{
struct deferred_unlink *next; /* Next unlink in the queue */
int dir_idx; /* Directory index in wd */
char *file_name; /* Name of the file to unlink, relative
to dir_idx */
bool is_dir; /* True if file_name is a directory */
off_t records_written; /* Number of records written when this
entry got added to the queue */
};
#define IS_CWD(p) \
((p)->is_dir \
&& ((p)->file_name[0] == 0 || strcmp ((p)->file_name, ".") == 0))
/* The unlink queue */
static struct deferred_unlink *dunlink_head, *dunlink_tail;
/* Number of entries in the queue */
static size_t dunlink_count;
/* List of entries available for allocation */
static struct deferred_unlink *dunlink_avail;
/* Delay (number of records written) between adding entry to the
list and its actual removal. */
static size_t deferred_unlink_delay = 0;
static struct deferred_unlink *
dunlink_alloc (void)
{
struct deferred_unlink *p;
if (dunlink_avail)
{
p = dunlink_avail;
dunlink_avail = p->next;
p->next = NULL;
}
else
p = xmalloc (sizeof (*p));
return p;
}
static void
dunlink_insert (struct deferred_unlink *anchor, struct deferred_unlink *p)
{
if (anchor)
{
p->next = anchor->next;
anchor->next = p;
}
else
{
p->next = dunlink_head;
dunlink_head = p;
}
if (!p->next)
dunlink_tail = p;
dunlink_count++;
}
static void
dunlink_reclaim (struct deferred_unlink *p)
{
free (p->file_name);
p->next = dunlink_avail;
dunlink_avail = p;
}
static void
flush_deferred_unlinks (bool force)
{
struct deferred_unlink *p, *prev = NULL;
int saved_chdir = chdir_current;
for (p = dunlink_head; p; )
{
struct deferred_unlink *next = p->next;
if (force
|| records_written > p->records_written + deferred_unlink_delay)
{
chdir_do (p->dir_idx);
if (p->is_dir)
{
const char *fname;
if (p->dir_idx && IS_CWD (p))
{
prev = p;
p = next;
continue;
}
else
fname = p->file_name;
if (unlinkat (chdir_fd, fname, AT_REMOVEDIR) != 0)
{
switch (errno)
{
case ENOENT:
/* nothing to worry about */
break;
case EEXIST:
/* OpenSolaris >=10 sets EEXIST instead of ENOTEMPTY
if trying to remove a non-empty directory */
case ENOTEMPTY:
/* Keep the record in list, in the hope we'll
be able to remove it later */
prev = p;
p = next;
continue;
default:
rmdir_error (fname);
}
}
}
else
{
if (unlinkat (chdir_fd, p->file_name, 0) != 0 && errno != ENOENT)
unlink_error (p->file_name);
}
dunlink_reclaim (p);
dunlink_count--;
p = next;
if (prev)
prev->next = p;
else
dunlink_head = p;
}
else
{
prev = p;
p = next;
}
}
if (!dunlink_head)
dunlink_tail = NULL;
else if (force)
{
for (p = dunlink_head; p; )
{
struct deferred_unlink *next = p->next;
const char *fname;
chdir_do (p->dir_idx);
if (p->dir_idx && IS_CWD (p))
{
fname = tar_dirname ();
chdir_do (p->dir_idx - 1);
}
else
fname = p->file_name;
if (unlinkat (chdir_fd, fname, AT_REMOVEDIR) != 0)
{
if (errno != ENOENT)
rmdir_error (fname);
}
dunlink_reclaim (p);
dunlink_count--;
p = next;
}
dunlink_head = dunlink_tail = NULL;
}
chdir_do (saved_chdir);
}
void
finish_deferred_unlinks (void)
{
flush_deferred_unlinks (true);
while (dunlink_avail)
{
struct deferred_unlink *next = dunlink_avail->next;
free (dunlink_avail);
dunlink_avail = next;
}
}
void
queue_deferred_unlink (const char *name, bool is_dir)
{
struct deferred_unlink *p;
if (dunlink_head
&& records_written > dunlink_head->records_written + deferred_unlink_delay)
flush_deferred_unlinks (false);
p = dunlink_alloc ();
p->next = NULL;
p->dir_idx = chdir_current;
p->file_name = xstrdup (name);
normalize_filename_x (p->file_name);
p->is_dir = is_dir;
p->records_written = records_written;
if (IS_CWD (p))
{
struct deferred_unlink *q, *prev;
for (q = dunlink_head, prev = NULL; q; prev = q, q = q->next)
if (IS_CWD (q) && q->dir_idx < p->dir_idx)
break;
if (q)
dunlink_insert (prev, p);
else
dunlink_insert (dunlink_tail, p);
}
else
dunlink_insert (dunlink_tail, p);
}
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