GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libc/gen/seekdir.c Lines: 0 16 0.0 %
Date: 2017-11-13 Branches: 0 16 0.0 %

Line Branch Exec Source
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/*	$OpenBSD: seekdir.c,v 1.13 2015/09/12 13:34:22 guenther Exp $ */
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/*
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 * Copyright (c) 2013 Ingo Schwarze <schwarze@openbsd.org>
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 *
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 * Permission to use, copy, modify, and distribute this software for any
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 * purpose with or without fee is hereby granted, provided that the above
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 * copyright notice and this permission notice appear in all copies.
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 *
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 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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 */
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#include <dirent.h>
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#include <unistd.h>
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#include "thread_private.h"
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#include "telldir.h"
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/*
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 * Seek to an entry in a directory.
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 * Only values returned by "telldir" should be passed to seekdir.
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 */
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void
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seekdir(DIR *dirp, long loc)
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{
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	struct dirent *dp;
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	/*
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	 * First check whether the directory entry to seek for
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	 * is still buffered in the directory structure in memory.
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	 */
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	_MUTEX_LOCK(&dirp->dd_lock);
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	if (dirp->dd_size && dirp->dd_bufpos == loc) {
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		dirp->dd_loc = 0;
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		dirp->dd_curpos = loc;
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		_MUTEX_UNLOCK(&dirp->dd_lock);
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		return;
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	}
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	for (dirp->dd_loc = 0;
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	     dirp->dd_loc < dirp->dd_size;
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	     dirp->dd_loc += dp->d_reclen) {
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		dp = (struct dirent *)(dirp->dd_buf + dirp->dd_loc);
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		if (dp->d_off != loc)
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			continue;
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		/*
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		 * Entry found in the buffer, use it.  If readdir(3)
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		 * follows, this will save us a getdents(2) syscall.
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		 * Note that d_off is the offset of the _next_ entry,
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		 * so advance dd_loc.
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		 */
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		dirp->dd_loc += dp->d_reclen;
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		dirp->dd_curpos = loc;
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		_MUTEX_UNLOCK(&dirp->dd_lock);
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		return;
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	}
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	/*
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	 * The entry is not in the buffer, prepare a call to getdents(2).
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	 * In particular, invalidate dd_loc.
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	 */
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	dirp->dd_loc = dirp->dd_size;
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	dirp->dd_bufpos = dirp->dd_curpos = lseek(dirp->dd_fd, loc, SEEK_SET);
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	_MUTEX_UNLOCK(&dirp->dd_lock);
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}
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DEF_WEAK(seekdir);