path: root/fs/smb/client/dir.c

// SPDX-License-Identifier: LGPL-2.1
/*
 *
 *   vfs operations that deal with dentries
 *
 *   Copyright (C) International Business Machines  Corp., 2002,2009
 *   Author(s): Steve French (sfrench@us.ibm.com)
 *
 */
#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/file.h>
#include "cifsfs.h"
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "cifs_fs_sb.h"
#include "cifs_unicode.h"
#include "fs_context.h"
#include "cifs_ioctl.h"
#include "fscache.h"

static void
renew_parental_timestamps(struct dentry *direntry)
{
	/* BB check if there is a way to get the kernel to do this or if we
	   really need this */
	do {
		cifs_set_time(direntry, jiffies);
		direntry = direntry->d_parent;
	} while (!IS_ROOT(direntry));
}

char *
cifs_build_path_to_root(struct smb3_fs_context *ctx, struct cifs_sb_info *cifs_sb,
			struct cifs_tcon *tcon, int add_treename)
{
	int pplen = ctx->prepath ? strlen(ctx->prepath) + 1 : 0;
	int dfsplen;
	char *full_path = NULL;

	/* if no prefix path, simply set path to the root of share to "" */
	if (pplen == 0) {
		full_path = kzalloc(1, GFP_KERNEL);
		return full_path;
	}

	if (add_treename)
		dfsplen = strnlen(tcon->tree_name, MAX_TREE_SIZE + 1);
	else
		dfsplen = 0;

	full_path = kmalloc(dfsplen + pplen + 1, GFP_KERNEL);
	if (full_path == NULL)
		return full_path;

	if (dfsplen)
		memcpy(full_path, tcon->tree_name, dfsplen);
	full_path[dfsplen] = CIFS_DIR_SEP(cifs_sb);
	memcpy(full_path + dfsplen + 1, ctx->prepath, pplen);
	convert_delimiter(full_path, CIFS_DIR_SEP(cifs_sb));
	return full_path;
}

/* Note: caller must free return buffer */
const char *
build_path_from_dentry(struct dentry *direntry, void *page)
{
	struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
	struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
	bool prefix = tcon->Flags & SMB_SHARE_IS_IN_DFS;

	return build_path_from_dentry_optional_prefix(direntry, page,
						      prefix);
}

char *__build_path_from_dentry_optional_prefix(struct dentry *direntry, void *page,
					       const char *tree, int tree_len,
					       bool prefix)
{
	int dfsplen;
	int pplen = 0;
	struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
	char dirsep = CIFS_DIR_SEP(cifs_sb);
	char *s;

	if (unlikely(!page))
		return ERR_PTR(-ENOMEM);

	if (prefix)
		dfsplen = strnlen(tree, tree_len + 1);
	else
		dfsplen = 0;

	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH)
		pplen = cifs_sb->prepath ? strlen(cifs_sb->prepath) + 1 : 0;

	s = dentry_path_raw(direntry, page, PATH_MAX);
	if (IS_ERR(s))
		return s;
	if (!s[1])	// for root we want "", not "/"
		s++;
	if (s < (char *)page + pplen + dfsplen)
		return ERR_PTR(-ENAMETOOLONG);
	if (pplen) {
		cifs_dbg(FYI, "using cifs_sb prepath <%s>\n", cifs_sb->prepath);
		s -= pplen;
		memcpy(s + 1, cifs_sb->prepath, pplen - 1);
		*s = '/';
	}
	if (dirsep != '/') {
		/* BB test paths to Windows with '/' in the midst of prepath */
		char *p;

		for (p = s; *p; p++)
			if (*p == '/')
				*p = dirsep;
	}
	if (dfsplen) {
		s -= dfsplen;
		memcpy(s, tree, dfsplen);
		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS) {
			int i;
			for (i = 0; i < dfsplen; i++) {
				if (s[i] == '\\')
					s[i] = '/';
			}
		}
	}
	return s;
}

char *build_path_from_dentry_optional_prefix(struct dentry *direntry, void *page,
					     bool prefix)
{
	struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
	struct cifs_tcon