166126c1e5
gcc 8.1.0 complains: fs/kernfs/symlink.c:91:3: warning: 'strncpy' output truncated before terminating nul copying as many bytes from a string as its length fs/kernfs/symlink.c: In function 'kernfs_iop_get_link': fs/kernfs/symlink.c:88:14: note: length computed here Using strncpy() is indeed less than perfect since the length of data to be copied has already been determined with strlen(). Replace strncpy() with memcpy() to address the warning and optimize the code a little. Signed-off-by: Guenter Roeck <linux@roeck-us.net> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
143 lines
3.0 KiB
C
143 lines
3.0 KiB
C
/*
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* fs/kernfs/symlink.c - kernfs symlink implementation
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*
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* Copyright (c) 2001-3 Patrick Mochel
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* Copyright (c) 2007 SUSE Linux Products GmbH
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* Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org>
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*
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* This file is released under the GPLv2.
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*/
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#include <linux/fs.h>
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#include <linux/gfp.h>
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#include <linux/namei.h>
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#include "kernfs-internal.h"
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/**
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* kernfs_create_link - create a symlink
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* @parent: directory to create the symlink in
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* @name: name of the symlink
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* @target: target node for the symlink to point to
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*
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* Returns the created node on success, ERR_PTR() value on error.
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*/
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struct kernfs_node *kernfs_create_link(struct kernfs_node *parent,
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const char *name,
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struct kernfs_node *target)
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{
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struct kernfs_node *kn;
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int error;
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kn = kernfs_new_node(parent, name, S_IFLNK|S_IRWXUGO, KERNFS_LINK);
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if (!kn)
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return ERR_PTR(-ENOMEM);
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if (kernfs_ns_enabled(parent))
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kn->ns = target->ns;
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kn->symlink.target_kn = target;
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kernfs_get(target); /* ref owned by symlink */
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error = kernfs_add_one(kn);
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if (!error)
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return kn;
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kernfs_put(kn);
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return ERR_PTR(error);
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}
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static int kernfs_get_target_path(struct kernfs_node *parent,
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struct kernfs_node *target, char *path)
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{
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struct kernfs_node *base, *kn;
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char *s = path;
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int len = 0;
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/* go up to the root, stop at the base */
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base = parent;
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while (base->parent) {
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kn = target->parent;
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while (kn->parent && base != kn)
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kn = kn->parent;
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if (base == kn)
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break;
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strcpy(s, "../");
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s += 3;
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base = base->parent;
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}
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/* determine end of target string for reverse fillup */
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kn = target;
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while (kn->parent && kn != base) {
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len += strlen(kn->name) + 1;
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kn = kn->parent;
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}
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/* check limits */
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if (len < 2)
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return -EINVAL;
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len--;
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if ((s - path) + len > PATH_MAX)
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return -ENAMETOOLONG;
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/* reverse fillup of target string from target to base */
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kn = target;
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while (kn->parent && kn != base) {
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int slen = strlen(kn->name);
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len -= slen;
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memcpy(s + len, kn->name, slen);
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if (len)
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s[--len] = '/';
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kn = kn->parent;
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}
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return 0;
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}
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static int kernfs_getlink(struct inode *inode, char *path)
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{
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struct kernfs_node *kn = inode->i_private;
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struct kernfs_node *parent = kn->parent;
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struct kernfs_node *target = kn->symlink.target_kn;
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int error;
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mutex_lock(&kernfs_mutex);
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error = kernfs_get_target_path(parent, target, path);
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mutex_unlock(&kernfs_mutex);
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return error;
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}
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static const char *kernfs_iop_get_link(struct dentry *dentry,
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struct inode *inode,
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struct delayed_call *done)
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{
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char *body;
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int error;
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if (!dentry)
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return ERR_PTR(-ECHILD);
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body = kzalloc(PAGE_SIZE, GFP_KERNEL);
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if (!body)
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return ERR_PTR(-ENOMEM);
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error = kernfs_getlink(inode, body);
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if (unlikely(error < 0)) {
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kfree(body);
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return ERR_PTR(error);
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}
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set_delayed_call(done, kfree_link, body);
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return body;
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}
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const struct inode_operations kernfs_symlink_iops = {
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.listxattr = kernfs_iop_listxattr,
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.get_link = kernfs_iop_get_link,
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.setattr = kernfs_iop_setattr,
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.getattr = kernfs_iop_getattr,
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.permission = kernfs_iop_permission,
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};
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