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      1 /*	$NetBSD: remove.c,v 1.3 2021/04/10 19:49:59 nia 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 1.3 2021/04/10 19:49:59 nia 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 *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 		for (i = PATH_MAX - 1; i > 0; --i) {
     88 			if (path[i] == '/')
     89 				break;
     90 		}
     91 		if (i == 0) {
     92 			errno = ENAMETOOLONG;
     93 			return -1; /* Assumes PATH_MAX > NAME_MAX */
     94 		}
     95 		memcpy(tmp_path, path, i);
     96 		tmp_path[i] = '\0';
     97 		if (chdir(tmp_path))
     98 			return -1;
     99 		*did_chdir = 1;
    100 		path += i + 1;
    101 		len -= i + 1;
    102 	}
    103 
    104 	if (remove(path) == 0 || (errno == ENOENT && missing_ok))
    105 		rv = 0;
    106 	else
    107 		rv = -1;
    108 
    109 	*path_ptr = path;
    110 
    111 	return rv;
    112 }
    113 
    114 static int
    115 recursive_remove_internal(const char *path, int missing_ok, int cwd)
    116 {
    117 	DIR *dir;
    118 	struct dirent *de;
    119 	const char *sub_path;
    120 	char *subdir;
    121 	int did_chdir, rv;
    122 
    123 	/*
    124 	 * If the argument is longer than PATH_MAX, long_remove
    125 	 * will try to shorten it using chdir.  So before returning,
    126 	 * make sure to fchdir back to the original cwd.
    127 	 */
    128 	sub_path = path;
    129 	if (long_remove(&sub_path, missing_ok, &did_chdir) == 0)
    130 		rv = 0;
    131 	else if (errno != ENOTEMPTY) /* Other errors are terminal. */
    132 		rv = -1;
    133 	else
    134 		rv = 1;
    135 
    136 	if (rv != 1) {
    137 		if (did_chdir && safe_fchdir(cwd) == -1 && rv == 0)
    138 			rv = -1;
    139 		return rv;
    140 	}
    141 
    142 	if ((dir = opendir(sub_path)) == NULL) {
    143 		if (errno == EMFILE)
    144 			warn("opendir failed");
    145 		return -1;
    146 	}
    147 
    148 	if (did_chdir && fchdir(cwd) == -1)
    149 		return -1;
    150 
    151 	rv = 0;
    152 
    153 	while ((de = readdir(dir)) != NULL) {
    154 		if (strcmp(de->d_name, ".") == 0)
    155 			continue;
    156 		if (strcmp(de->d_name, "..") == 0)
    157 			continue;
    158 		subdir = xasprintf("%s/%s", path, de->d_name);
    159 		rv = recursive_remove_internal(subdir, 1, cwd);
    160 		free(subdir);
    161 	}
    162 
    163 	closedir(dir);
    164 
    165 	safe_fchdir(cwd);
    166 
    167 	rv |= long_remove(&path, missing_ok, &did_chdir);
    168 
    169 	if (did_chdir && safe_fchdir(cwd) == -1 && rv == 0)
    170 		rv = -1;
    171 
    172 	return rv;
    173 }
    174 
    175 int
    176 recursive_remove(const char *path, int missing_ok)
    177 {
    178 	int orig_cwd, rv;
    179 
    180 	/* First try the easy case of regular file or empty directory. */
    181 	if (remove(path) == 0 || (errno == ENOENT && missing_ok))
    182 		return 0;
    183 
    184 	/*
    185 	 * If the path is too long, long_remove will use chdir to shorten it,
    186 	 * so remember the current directory first.
    187 	 */
    188 	if ((orig_cwd = open(".", O_RDONLY)) == -1)
    189 		return -1;
    190 
    191 	rv = recursive_remove_internal(path, missing_ok, orig_cwd);
    192 
    193 	close(orig_cwd);
    194 	return rv;
    195 }
    196