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remove.c revision 1.1.1.1.10.2 
      1 /*	$NetBSD: remove.c,v 1.1.1.1.10.2 2009/06/05 17:19:41 snj Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2008 Joerg Sonnenberger <joerg (at) NetBSD.org>.
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  *
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in
     15  *    the documentation and/or other materials provided with the
     16  *    distribution.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     21  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
     22  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     23  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
     24  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     25  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     26  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     27  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
     28  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #if HAVE_CONFIG_H
     33 #include "config.h"
     34 #endif
     35 
     36 #include <nbcompat.h>
     37 
     38 #if HAVE_SYS_CDEFS_H
     39 #include <sys/cdefs.h>
     40 #endif
     41 
     42 __RCSID("$NetBSD: remove.c,v 1.1.1.1.10.2 2009/06/05 17:19:41 snj Exp $");
     43 
     44 #if HAVE_DIRENT_H
     45 #include <dirent.h>
     46 #endif
     47 #if HAVE_ERR_H
     48 #include <err.h>
     49 #endif
     50 #include <errno.h>
     51 #if HAVE_FCNTL_H
     52 #include <fcntl.h>
     53 #endif
     54 #include <limits.h>
     55 #include <stdio.h>
     56 #include <stdlib.h>
     57 #include <string.h>
     58 #include <unistd.h>
     59 
     60 #include "lib.h"
     61 
     62 static int
     63 safe_fchdir(int cwd)
     64 {
     65 	int tmp_errno, rv;
     66 
     67 	tmp_errno = errno;
     68 	rv = fchdir(cwd);
     69 	errno = tmp_errno;
     70 
     71 	return rv;
     72 }
     73 
     74 static int
     75 long_remove(const char **path_ptr, int missing_ok, int *did_chdir)
     76 {
     77 	char tmp_path[PATH_MAX + 1];
     78 	const char *slash, *path;
     79 	size_t i, len;
     80 	int rv;
     81 
     82 	path = *path_ptr;
     83 	len = strlen(path);
     84 	*did_chdir = 0;
     85 
     86 	while (len >= PATH_MAX) {
     87 		slash = path;
     88 		for (i = PATH_MAX - 1; i > 0; --i) {
     89 			if (path[i] == '/')
     90 				break;
     91 		}
     92 		if (i == 0) {
     93 			errno = ENAMETOOLONG;
     94 			return -1; /* Assumes PATH_MAX > NAME_MAX */
     95 		}
     96 		memcpy(tmp_path, path, i);
     97 		tmp_path[i] = '\0';
     98 		if (chdir(tmp_path))
     99 			return -1;
    100 		*did_chdir = 1;
    101 		path += i + 1;
    102 		len -= i + 1;
    103 	}
    104 
    105 	if (remove(path) == 0 || (errno == ENOENT && missing_ok))
    106 		rv = 0;
    107 	else
    108 		rv = -1;
    109 
    110 	*path_ptr = path;
    111 
    112 	return rv;
    113 }
    114 
    115 static int
    116 recursive_remove_internal(const char *path, int missing_ok, int cwd)
    117 {
    118 	DIR *dir;
    119 	struct dirent *de;
    120 	const char *sub_path;
    121 	char *subdir;
    122 	int did_chdir, rv;
    123 
    124 	/*
    125 	 * If the argument is longer than PATH_MAX, long_remove
    126 	 * will try to shorten it using chdir.  So before returning,
    127 	 * make sure to fchdir back to the original cwd.
    128 	 */
    129 	sub_path = path;
    130 	if (long_remove(&sub_path, missing_ok, &did_chdir) == 0)
    131 		rv = 0;
    132 	else if (errno != ENOTEMPTY) /* Other errors are terminal. */
    133 		rv = -1;
    134 	else
    135 		rv = 1;
    136 
    137 	if (rv != 1) {
    138 		if (did_chdir && safe_fchdir(cwd) == -1 && rv == 0)
    139 			rv = -1;
    140 		return rv;
    141 	}
    142 
    143 	if ((dir = opendir(sub_path)) == NULL) {
    144 		if (errno == EMFILE)
    145 			warn("opendir failed");
    146 		return -1;
    147 	}
    148 
    149 	if (did_chdir && fchdir(cwd) == -1)
    150 		return -1;
    151 
    152 	rv = 0;
    153 
    154 	while ((de = readdir(dir)) != NULL) {
    155 		if (strcmp(de->d_name, ".") == 0)
    156 			continue;
    157 		if (strcmp(de->d_name, "..") == 0)
    158 			continue;
    159 		subdir = xasprintf("%s/%s", path, de->d_name);
    160 		rv = recursive_remove_internal(subdir, 1, cwd);
    161 		free(subdir);
    162 	}
    163 
    164 	closedir(dir);
    165 
    166 	safe_fchdir(cwd);
    167 
    168 	rv |= long_remove(&path, missing_ok, &did_chdir);
    169 
    170 	if (did_chdir && safe_fchdir(cwd) == -1 && rv == 0)
    171 		rv = -1;
    172 
    173 	return rv;
    174 }
    175 
    176 int
    177 recursive_remove(const char *path, int missing_ok)
    178 {
    179 	int orig_cwd, rv;
    180 
    181 	/* First try the easy case of regular file or empty directory. */
    182 	if (remove(path) == 0 || (errno == ENOENT && missing_ok))
    183 		return 0;
    184 
    185 	/*
    186 	 * If the path is too long, long_remove will use chdir to shorten it,
    187 	 * so remember the current directory first.
    188 	 */
    189 	if ((orig_cwd = open(".", O_RDONLY)) == -1)
    190 		return -1;
    191 
    192 	rv = recursive_remove_internal(path, missing_ok, orig_cwd);
    193 
    194 	close(orig_cwd);
    195 	return rv;
    196 }
    197