fts.c

压缩包中包含LINUX下多个命令的源码

/*-
 * Copyright (c) 1990, 1993, 1994
 *	The Regents of the University of California.  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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)fts.c	8.6 (Berkeley) 8/14/94";
#endif /* LIBC_SCCS and not lint */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <sys/param.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <dirent.h>
#include <errno.h>
#include <stdlib.h>
#ifdef HAVE_STRING_H
#include <string.h>
#else
#include <strings.h>
#endif
#include <unistd.h>

#include "bsdport.h"
#include "fts.h"

static FTSENT	*fts_alloc(FTS *, const char *, int);
static FTSENT	*fts_build(FTS *, int);
static void	 fts_lfree(FTSENT *);
static void	 fts_load(FTS *, FTSENT *);
static size_t	 fts_maxarglen(char * const *);
static void	 fts_padjust(FTS *, void *);
static int	 fts_palloc(FTS *, size_t);
static FTSENT	*fts_sort(FTS *, FTSENT *, int);
static u_short	 fts_stat(FTS *, struct dirent *, FTSENT *, int);

#ifndef MAX
#define MAX(a, b)	(((a) > (b)) ? (a) : (b))
#endif

#define	ISDOT(a)	(a[0] == '.' && (!a[1] || (a[1] == '.' && !a[2])))

#define	ISSET(opt)	(sp->fts_options & opt)
#define	SET(opt)	(sp->fts_options |= opt)

#define	CHDIR(sp, path)	(!ISSET(FTS_NOCHDIR) && chdir(path))
#ifdef HAVE_FCHDIR
#define	FCHDIR(sp, fd)	(!ISSET(FTS_NOCHDIR) && fchdir(fd))
#else
#define FCHDIR(sp, fd)  (!ISSET(FTS_NOCHDIR) && -1)
#endif

/* fts_build flags */
#define	BCHILD		1		/* fts_children */
#define	BNAMES		2		/* fts_children, names only */
#define	BREAD		3		/* fts_read */

FTS *
fts_open(argv, options, compar)
	char * const *argv;
	register int options;
	int (*compar) __P((const FTSENT **, const FTSENT **));
{
	register FTS *sp;
	register FTSENT *p, *root;
	register int nitems;
	FTSENT *parent;
	FTSENT *tmp=NULL;
	int len;

	/* Options check. */
	if (options & ~FTS_OPTIONMASK) {
		errno = EINVAL;
		return (NULL);
	}

	/* Allocate/initialize the stream */
	if ((sp = malloc((u_int)sizeof(FTS))) == NULL)
		return (NULL);
	memset(sp, 0, sizeof(FTS));
	sp->fts_compar = (int (*) __P((const void *, const void *))) compar;
	sp->fts_options = options;

	/* Logical walks turn on NOCHDIR; symbolic links are too hard. */
	if (ISSET(FTS_LOGICAL))
		SET(FTS_NOCHDIR);

	/* Always set NOCHDIR for OS lacking fchdir ()  */
#ifndef HAVE_FCHDIR
	SET(FTS_NOCHDIR);
#endif
	/*
	 * Start out with 1K of path space, and enough, in any case,
	 * to hold the user's paths.
	 */
#ifndef MAXPATHLEN
#define MAXPATHLEN 1024
#endif
	if (fts_palloc(sp, MAX(fts_maxarglen(argv), MAXPATHLEN)))
		goto mem1;

	/* Allocate/initialize root's parent. */
	if ((parent = fts_alloc(sp, "", 0)) == NULL)
		goto mem2;
	parent->fts_level = FTS_ROOTPARENTLEVEL;

	/* Allocate/initialize root(s). */
	for (root = NULL, nitems = 0; *argv; ++argv, ++nitems) {
		/* Don't allow zero-length paths. */
		if ((len = strlen(*argv)) == 0) {
			errno = ENOENT;
			goto mem3;
		}

		p = fts_alloc(sp, *argv, len);
		p->fts_level = FTS_ROOTLEVEL;
		p->fts_parent = parent;
		p->fts_accpath = p->fts_name;
		p->fts_info = fts_stat(sp, NULL, p, ISSET(FTS_COMFOLLOW));

		/* Command-line "." and ".." are real directories. */
		if (p->fts_info == FTS_DOT)
			p->fts_info = FTS_D;

		/*
		 * If comparison routine supplied, traverse in sorted
		 * order; otherwise traverse in the order specified.
		 */
		if (compar) {
			p->fts_link = root;
			root = p;
		} else {
			p->fts_link = NULL;
			if (root == NULL)
				tmp = root = p;
			else {
				tmp->fts_link = p;
				tmp = p;
			}
		}
	}
	if (compar && nitems > 1)
		root = fts_sort(sp, root, nitems);

	/*
	 * Allocate a dummy pointer and make fts_read think that we've just
	 * finished the node before the root(s); set p->fts_info to FTS_INIT
	 * so that everything about the "current" node is ignored.
	 */
	if ((sp->fts_cur = fts_alloc(sp, "", 0)) == NULL)
		goto mem3;
	sp->fts_cur->fts_link = root;
	sp->fts_cur->fts_info = FTS_INIT;

	/*
	 * If using chdir(2), grab a file descriptor pointing to dot to insure
	 * that we can get back here; this could be avoided for some paths,
	 * but almost certainly not worth the effort.  Slashes, symbolic links,
	 * and ".." are all fairly nasty problems.  Note, if we can't get the
	 * descriptor we run anyway, just more slowly.
	 */
	if (!ISSET(FTS_NOCHDIR)
	    && (sp->fts_rfd = open(".", O_RDONLY, 0)) < 0)
		SET(FTS_NOCHDIR);

	return (sp);

mem3:	fts_lfree(root);
	free(parent);
mem2:	free(sp->fts_path);
mem1:	free(sp);
	return (NULL);
}

static void
fts_load(sp, p)
	FTS *sp;
	register FTSENT *p;
{
	register int len;
	register char *cp;

	/*
	 * Load the stream structure for the next traversal.  Since we don't
	 * actually enter the directory until after the preorder visit, set
	 * the fts_accpath field specially so the chdir gets done to the right
	 * place and the user can access the first node.  From fts_open it's
	 * known that the path will fit.
	 */
	len = p->fts_pathlen = p->fts_namelen;
	memmove (sp->fts_path, p->fts_name, len + 1);
	if ((cp = rindex(p->fts_name, '/')) && (cp != p->fts_name || cp[1])) {
		len = strlen(++cp);
		memmove(p->fts_name, cp, len + 1);
		p->fts_namelen = len;
	}
	p->fts_accpath = p->fts_path = sp->fts_path;
	sp->fts_dev = p->fts_dev;
}

int
fts_close(sp)
	FTS *sp;
{
	register FTSENT *freep, *p;
	int saved_errno=0;
	int retval = 0;

	/*
	 * This still works if we haven't read anything -- the dummy structure
	 * points to the root list, so we step through to the end of the root
	 * list which has a valid parent pointer.
	 */
	if (sp->fts_cur) {
		for (p = sp->fts_cur; p->fts_level >= FTS_ROOTLEVEL;) {
			freep = p;
			p = p->fts_link ? p->fts_link : p->fts_parent;
			free(freep);
		}
		free(p);
	}

	/* Free up child linked list, sort array, path buffer. */
	if (sp->fts_child)
		fts_lfree(sp->fts_child);
	if (sp->fts_array)
		free(sp->fts_array);
	free(sp->fts_path);

	/* Return to original directory, save errno if necessary. */
	if (!ISSET(FTS_NOCHDIR)) {
		saved_errno = fchdir(sp->fts_rfd) ? errno : 0;
		(void)close(sp->fts_rfd);
	}

	/* Set errno and return. */
	if (!ISSET(FTS_NOCHDIR) && saved_errno) {
		errno = saved_errno;
		retval = -1;
	}

	/* Free up the stream pointer. */
	free (sp);

	return retval;
}

/*
 * Special case a root of "/" so that slashes aren't appended which would
 * cause paths to be written as "//foo".
 */
#define	NAPPEND(p)							\
	(p->fts_level == FTS_ROOTLEVEL && p->fts_pathlen == 1 &&	\
	    p->fts_path[0] == '/' ? 0 : p->fts_pathlen)

FTSENT *
fts_read(sp)
	register FTS *sp;
{
	register FTSENT *p;
	register FTSENT *tmp;
	register int instr;
	register char *t;
	int saved_errno;

	/* If finished or unrecoverable error, return NULL. */
	if (sp->fts_cur == NULL || ISSET(FTS_STOP))
		return (NULL);

	/* Set current node pointer. */
	p = sp->fts_cur;

	/* Save and zero out user instructions. */
	instr = p->fts_instr;
	p->fts_instr = FTS_NOINSTR;

	/* Any type of file may be re-visited; re-stat and re-turn. */
	if (instr == FTS_AGAIN) {
		p->fts_info = fts_stat(sp, NULL, p, 0);
		return (p);
	}

	/*
	 * Following a symlink -- SLNONE test allows application to see
	 * SLNONE and recover.  If indirecting through a symlink, have
	 * keep a pointer to current location.  If unable to get that
	 * pointer, follow fails.
	 */
	if (instr == FTS_FOLLOW &&
	    (p->fts_info == FTS_SL || p->fts_info == FTS_SLNONE)) {
		p->fts_info = fts_stat(sp, NULL, p, 1);
		if (p->fts_info == FTS_D && !ISSET(FTS_NOCHDIR)) {
			if ((p->fts_symfd = open(".", O_RDONLY, 0)) < 0) {
				p->fts_errno = errno;
				p->fts_info = FTS_ERR;
			} else
				p->fts_flags |= FTS_SYMFOLLOW;
		}
		return (p);
	}

	/* Directory in pre-order. */
	if (p->fts_info == FTS_D) {
		/* If skipped or crossed mount point, do post-order visit. */
		if (instr == FTS_SKIP ||
		    (ISSET(FTS_XDEV) && p->fts_dev != sp->fts_dev)) {
			if (p->fts_flags & FTS_SYMFOLLOW)
				(void)close(p->fts_symfd);
			if (sp->fts_child) {
				fts_lfree(sp->fts_child);
				sp->fts_child = NULL;
			}
			p->fts_info = FTS_DP;
			return (p);
		}

		/* Rebuild if only read the names and now traversing. */
		if (sp->fts_child && sp->fts_options & FTS_NAMEONLY) {
			sp->fts_options &= ~FTS_NAMEONLY;
			fts_lfree(sp->fts_child);
			sp->fts_child = NULL;
		}

		/*
		 * Cd to the subdirectory.
		 *
		 * If have already read and now fail to chdir, whack the list
		 * to make the names come out right, and set the parent errno
		 * so the application will eventually get an error condition.
		 * Set the FTS_DONTCHDIR flag so that when we logically change
		 * directories back to the parent we don't do a chdir.
		 *
		 * If haven't read do so.  If the read fails, fts_build sets
		 * FTS_STOP or the fts_info field of the node.
		 */
		if (sp->fts_child) {
			if (CHDIR(sp, p->fts_accpath)) {
				p->fts_errno = errno;
				p->fts_flags |= FTS_DONTCHDIR;
				for (p = sp->fts_child; p; p = p->fts_link)
					p->fts_accpath =
					    p->fts_parent->fts_accpath;
			}
		} else if ((sp->fts_child = fts_build(sp, BREAD)) == NULL) {
			if (ISSET(FTS_STOP))
				return (NULL);
			return (p);
		}
		p = sp->fts_child;
		sp->fts_child = NULL;
		goto name;
	}

	/* Move to the next node on this level. */
next:	tmp = p;
	if ((p = p->fts_link)) {
		free(tmp);

		/*
		 * If reached the top, return to the original directory, and
		 * load the paths for the next root.
		 */
		if (p->fts_level == FTS_ROOTLEVEL) {
			if (!ISSET(FTS_NOCHDIR) && FCHDIR(sp, sp->fts_rfd)) {
				SET(FTS_STOP);
				return (NULL);
			}
			fts_load(sp, p);
			return (sp->fts_cur = p);
		}

		/*
		 * User may have called fts_set on the node.  If skipped,
		 * ignore.  If followed, get a file descriptor so we can
		 * get back if necessary.
		 */
		if (p->fts_instr == FTS_SKIP)
			goto next;
		if (p->fts_instr == FTS_FOLLOW) {
			p->fts_info = fts_stat(sp, NULL, p, 1);
			if (p->fts_info == FTS_D && !ISSET(FTS_NOCHDIR)) {
				if ((p->fts_symfd =
				    open(".", O_RDONLY, 0)) < 0) {
					p->fts_errno = errno;
					p->fts_info = FTS_ERR;
				} else
					p->fts_flags |= FTS_SYMFOLLOW;
			}
			p->fts_instr = FTS_NOINSTR;
		}

name:		t = sp->fts_path + NAPPEND(p->fts_parent);
		*t++ = '/';
		memmove(t, p->fts_name, p->fts_namelen + 1);
		return (sp->fts_cur = p);
	}

	/* Move up to the parent node. */
	p = tmp->fts_parent;
	free(tmp);

	if (p->fts_level == FTS_ROOTPARENTLEVEL) {
		/*
		 * Done; free everything up and set errno to 0 so the user
		 * can distinguish between error and EOF.
		 */
		free(p);
		errno = 0;
		return (sp->fts_cur = NULL);
	}

	/* Nul terminate the pathname. */
	sp->fts_path[p->fts_pathlen] = '\0';

	/*
	 * Return to the parent directory.  If at a root node or came through
	 * a symlink, go back through the file descriptor.  Otherwise, cd up
	 * one directory.
	 */
	if (p->fts_level == FTS_ROOTLEVEL) {
		if (!ISSET(FTS_NOCHDIR) && FCHDIR(sp, sp->fts_rfd)) {
			SET(FTS_STOP);
			return (NULL);
		}
	} else if (p->fts_flags & FTS_SYMFOLLOW) {
		if (FCHDIR(sp, p->fts_symfd)) {
			saved_errno = errno;
			(void)close(p->fts_symfd);
			errno = saved_errno;
			SET(FTS_STOP);
			return (NULL);
		}
		(void)close(p->fts_symfd);
	} else if (!(p->fts_flags & FTS_DONTCHDIR)) {
		if (CHDIR(sp, "..")) {
			SET(FTS_STOP);
			return (NULL);
		}
	}
	p->fts_info = p->fts_errno ? FTS_ERR : FTS_DP;
	return (sp->fts_cur = p);
}

/*
 * Fts_set takes the stream as an argument although it's not used in this
 * implementation; it would be necessary if anyone wanted to add global
 * semantics to fts using fts_set.  An error return is allowed for similar
 * reasons.
 */
/* ARGSUSED */
int
fts_set(sp, p, instr)
	FTS *sp;
	FTSENT *p;
	int instr;
{
	if (instr && instr != FTS_AGAIN && instr != FTS_FOLLOW &&
	    instr != FTS_NOINSTR && instr != FTS_SKIP) {
		errno = EINVAL;
		return (1);
	}
	p->fts_instr = instr;
	return (0);
}

FTSENT *
fts_children(sp, instr)
	register FTS *sp;
	int instr;
{
	register FTSENT *p;
	int fd;

	if (instr && instr != FTS_NAMEONLY) {
		errno = EINVAL;
		return (NULL);
	}

	/* Set current node pointer. */
	p = sp->fts_cur;

	/*
	 * Errno set to 0 so user can distinguish empty directory from
	 * an error.
	 */
	errno = 0;