/* * fs/kernfs/symlink.c - kernfs symlink implementation * * Copyright (c) 2001-3 Patrick Mochel * Copyright (c) 2007 SUSE Linux Products GmbH * Copyright (c) 2007, 2013 Tejun Heo * * This file is released under the GPLv2. */ #include #include #include #include "kernfs-internal.h" /** * kernfs_create_link - create a symlink * @parent: directory to create the symlink in * @name: name of the symlink * @target: target node for the symlink to point to * * Returns the created node on success, ERR_PTR() value on error. */ struct kernfs_node *kernfs_create_link(struct kernfs_node *parent, const char *name, struct kernfs_node *target) { struct kernfs_node *kn; int error; kn = kernfs_new_node(parent, name, S_IFLNK|S_IRWXUGO, KERNFS_LINK); if (!kn) return ERR_PTR(-ENOMEM); if (kernfs_ns_enabled(parent)) kn->ns = target->ns; kn->symlink.target_kn = target; kernfs_get(target); /* ref owned by symlink */ error = kernfs_add_one(kn); if (!error) return kn; kernfs_put(kn); return ERR_PTR(error); } static int kernfs_get_target_path(struct kernfs_node *parent, struct kernfs_node *target, char *path) { struct kernfs_node *base, *kn; char *s = path; int len = 0; /* go up to the root, stop at the base */ base = parent; while (base->parent) { kn = target->parent; while (kn->parent && base != kn) kn = kn->parent; if (base == kn) break; strcpy(s, "../"); s += 3; base = base->parent; } /* determine end of target string for reverse fillup */ kn = target; while (kn->parent && kn != base) { len += strlen(kn->name) + 1; kn = kn->parent; } /* check limits */ if (len < 2) return -EINVAL; len--; if ((s - path) + len > PATH_MAX) return -ENAMETOOLONG; /* reverse fillup of target string from target to base */ kn = target; while (kn->parent && kn != base) { int slen = strlen(kn->name); len -= slen; strncpy(s + len, kn->name, slen); if (len) s[--len] = '/'; kn = kn->parent; } return 0; } static int kernfs_getlink(struct dentry *dentry, char *path) { struct kernfs_node *kn = dentry->d_fsdata; struct kernfs_node *parent = kn->parent; struct kernfs_node *target = kn->symlink.target_kn; int error; mutex_lock(&kernfs_mutex); error = kernfs_get_target_path(parent, target, path); mutex_unlock(&kernfs_mutex); return error; } static const char *kernfs_iop_get_link(struct dentry *dentry, struct inode *inode, struct delayed_call *done) { char *body; int error; if (!dentry) return ERR_PTR(-ECHILD); body = kzalloc(PAGE_SIZE, GFP_KERNEL); if (!body) return ERR_PTR(-ENOMEM); error = kernfs_getlink(dentry, body); if (unlikely(error < 0)) { kfree(body); return ERR_PTR(error); } set_delayed_call(done, kfree_link, body); return body; } const struct inode_operations kernfs_symlink_iops = { .listxattr = kernfs_iop_listxattr, .get_link = kernfs_iop_get_link, .setattr = kernfs_iop_setattr, .getattr = kernfs_iop_getattr, .permission = kernfs_iop_permission, }; ound/soc/codecs/wm0010.c

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