X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=fs%2Fsysfs%2Fsymlink.c;h=1b9a3a1e8a17a1e3951980b3b4179d06a2b0a916;hb=7cb32942d91a501b2df944928ccc9e6590ab237b;hp=43cc5222f136bcce5c0e1549f281875d7478f21b;hpb=608e266a2d4e62c1b98c1c573064b6afe8c06a58;p=safe%2Fjmp%2Flinux-2.6 diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c index 43cc522..1b9a3a1 100644 --- a/fs/sysfs/symlink.c +++ b/fs/sysfs/symlink.c @@ -1,5 +1,13 @@ /* - * symlink.c - operations for sysfs symlinks. + * fs/sysfs/symlink.c - sysfs symlink implementation + * + * Copyright (c) 2001-3 Patrick Mochel + * Copyright (c) 2007 SUSE Linux Products GmbH + * Copyright (c) 2007 Tejun Heo + * + * This file is released under the GPLv2. + * + * Please see Documentation/filesystems/sysfs.txt for more information. */ #include @@ -7,102 +15,95 @@ #include #include #include -#include +#include +#include #include "sysfs.h" -static int object_depth(struct sysfs_dirent *sd) -{ - int depth = 0; - - for (; sd->s_parent; sd = sd->s_parent) - depth++; - - return depth; -} - -static int object_path_length(struct sysfs_dirent * sd) -{ - int length = 1; - - for (; sd->s_parent; sd = sd->s_parent) - length += strlen(sd->s_name) + 1; - - return length; -} - -static void fill_object_path(struct sysfs_dirent *sd, char *buffer, int length) -{ - --length; - for (; sd->s_parent; sd = sd->s_parent) { - int cur = strlen(sd->s_name); - - /* back up enough to print this bus id with '/' */ - length -= cur; - strncpy(buffer + length, sd->s_name, cur); - *(buffer + --length) = '/'; - } -} - -static int sysfs_add_link(struct sysfs_dirent * parent_sd, const char * name, - struct sysfs_dirent * target_sd) -{ - struct sysfs_dirent * sd; - - sd = sysfs_new_dirent(name, S_IFLNK|S_IRWXUGO, SYSFS_KOBJ_LINK); - if (!sd) - return -ENOMEM; - - sd->s_elem.symlink.target_sd = target_sd; - sysfs_attach_dirent(sd, parent_sd, NULL); - return 0; -} - -/** - * sysfs_create_link - create symlink between two objects. - * @kobj: object whose directory we're creating the link in. - * @target: object we're pointing to. - * @name: name of the symlink. - */ -int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char * name) +static int sysfs_do_create_link(struct kobject *kobj, struct kobject *target, + const char *name, int warn) { struct sysfs_dirent *parent_sd = NULL; struct sysfs_dirent *target_sd = NULL; - int error = -EEXIST; + struct sysfs_dirent *sd = NULL; + struct sysfs_addrm_cxt acxt; + int error; BUG_ON(!name); - if (!kobj) { - if (sysfs_mount && sysfs_mount->mnt_sb) - parent_sd = sysfs_mount->mnt_sb->s_root->d_fsdata; - } else + if (!kobj) + parent_sd = &sysfs_root; + else parent_sd = kobj->sd; + error = -EFAULT; if (!parent_sd) - return -EFAULT; + goto out_put; /* target->sd can go away beneath us but is protected with - * kobj_sysfs_assoc_lock. Fetch target_sd from it. + * sysfs_assoc_lock. Fetch target_sd from it. */ - spin_lock(&kobj_sysfs_assoc_lock); + spin_lock(&sysfs_assoc_lock); if (target->sd) target_sd = sysfs_get(target->sd); - spin_unlock(&kobj_sysfs_assoc_lock); + spin_unlock(&sysfs_assoc_lock); + error = -ENOENT; if (!target_sd) - return -ENOENT; + goto out_put; + + error = -ENOMEM; + sd = sysfs_new_dirent(name, S_IFLNK|S_IRWXUGO, SYSFS_KOBJ_LINK); + if (!sd) + goto out_put; + + sd->s_symlink.target_sd = target_sd; + target_sd = NULL; /* reference is now owned by the symlink */ - mutex_lock(&parent_sd->s_dentry->d_inode->i_mutex); - if (!sysfs_find_dirent(parent_sd, name)) - error = sysfs_add_link(parent_sd, name, target_sd); - mutex_unlock(&parent_sd->s_dentry->d_inode->i_mutex); + sysfs_addrm_start(&acxt, parent_sd); + if (warn) + error = sysfs_add_one(&acxt, sd); + else + error = __sysfs_add_one(&acxt, sd); + sysfs_addrm_finish(&acxt); if (error) - sysfs_put(target_sd); + goto out_put; + return 0; + + out_put: + sysfs_put(target_sd); + sysfs_put(sd); return error; } +/** + * sysfs_create_link - create symlink between two objects. + * @kobj: object whose directory we're creating the link in. + * @target: object we're pointing to. + * @name: name of the symlink. + */ +int sysfs_create_link(struct kobject *kobj, struct kobject *target, + const char *name) +{ + return sysfs_do_create_link(kobj, target, name, 1); +} + +/** + * sysfs_create_link_nowarn - create symlink between two objects. + * @kobj: object whose directory we're creating the link in. + * @target: object we're pointing to. + * @name: name of the symlink. + * + * This function does the same as sysf_create_link(), but it + * doesn't warn if the link already exists. + */ +int sysfs_create_link_nowarn(struct kobject *kobj, struct kobject *target, + const char *name) +{ + return sysfs_do_create_link(kobj, target, name, 0); +} /** * sysfs_remove_link - remove symlink in object's directory. @@ -112,27 +113,102 @@ int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char void sysfs_remove_link(struct kobject * kobj, const char * name) { - sysfs_hash_and_remove(kobj->sd, name); + struct sysfs_dirent *parent_sd = NULL; + + if (!kobj) + parent_sd = &sysfs_root; + else + parent_sd = kobj->sd; + + sysfs_hash_and_remove(parent_sd, name); +} + +/** + * sysfs_rename_link - rename symlink in object's directory. + * @kobj: object we're acting for. + * @targ: object we're pointing to. + * @old: previous name of the symlink. + * @new: new name of the symlink. + * + * A helper function for the common rename symlink idiom. + */ +int sysfs_rename_link(struct kobject *kobj, struct kobject *targ, + const char *old, const char *new) +{ + struct sysfs_dirent *parent_sd, *sd = NULL; + int result; + + if (!kobj) + parent_sd = &sysfs_root; + else + parent_sd = kobj->sd; + + result = -ENOENT; + sd = sysfs_get_dirent(parent_sd, old); + if (!sd) + goto out; + + result = -EINVAL; + if (sysfs_type(sd) != SYSFS_KOBJ_LINK) + goto out; + if (sd->s_symlink.target_sd->s_dir.kobj != targ) + goto out; + + result = sysfs_rename(sd, parent_sd, new); + +out: + sysfs_put(sd); + return result; } -static int sysfs_get_target_path(struct sysfs_dirent * parent_sd, - struct sysfs_dirent * target_sd, char *path) +static int sysfs_get_target_path(struct sysfs_dirent *parent_sd, + struct sysfs_dirent *target_sd, char *path) { - char * s; - int depth, size; + struct sysfs_dirent *base, *sd; + char *s = path; + int len = 0; + + /* go up to the root, stop at the base */ + base = parent_sd; + while (base->s_parent) { + sd = target_sd->s_parent; + while (sd->s_parent && base != sd) + sd = sd->s_parent; + + if (base == sd) + break; + + strcpy(s, "../"); + s += 3; + base = base->s_parent; + } - depth = object_depth(parent_sd); - size = object_path_length(target_sd) + depth * 3 - 1; - if (size > PATH_MAX) + /* determine end of target string for reverse fillup */ + sd = target_sd; + while (sd->s_parent && sd != base) { + len += strlen(sd->s_name) + 1; + sd = sd->s_parent; + } + + /* check limits */ + if (len < 2) + return -EINVAL; + len--; + if ((s - path) + len > PATH_MAX) return -ENAMETOOLONG; - pr_debug("%s: depth = %d, size = %d\n", __FUNCTION__, depth, size); + /* reverse fillup of target string from target to base */ + sd = target_sd; + while (sd->s_parent && sd != base) { + int slen = strlen(sd->s_name); - for (s = path; depth--; s += 3) - strcpy(s,"../"); + len -= slen; + strncpy(s + len, sd->s_name, slen); + if (len) + s[--len] = '/'; - fill_object_path(target_sd, path, size); - pr_debug("%s: path = '%s'\n", __FUNCTION__, path); + sd = sd->s_parent; + } return 0; } @@ -141,12 +217,12 @@ static int sysfs_getlink(struct dentry *dentry, char * path) { struct sysfs_dirent *sd = dentry->d_fsdata; struct sysfs_dirent *parent_sd = sd->s_parent; - struct sysfs_dirent *target_sd = sd->s_elem.symlink.target_sd; + struct sysfs_dirent *target_sd = sd->s_symlink.target_sd; int error; - down_read(&sysfs_rename_sem); + mutex_lock(&sysfs_mutex); error = sysfs_get_target_path(parent_sd, target_sd, path); - up_read(&sysfs_rename_sem); + mutex_unlock(&sysfs_mutex); return error; } @@ -155,8 +231,11 @@ static void *sysfs_follow_link(struct dentry *dentry, struct nameidata *nd) { int error = -ENOMEM; unsigned long page = get_zeroed_page(GFP_KERNEL); - if (page) + if (page) { error = sysfs_getlink(dentry, (char *) page); + if (error < 0) + free_page((unsigned long)page); + } nd_set_link(nd, error ? ERR_PTR(error) : (char *)page); return NULL; } @@ -169,9 +248,13 @@ static void sysfs_put_link(struct dentry *dentry, struct nameidata *nd, void *co } const struct inode_operations sysfs_symlink_inode_operations = { - .readlink = generic_readlink, - .follow_link = sysfs_follow_link, - .put_link = sysfs_put_link, + .setxattr = sysfs_setxattr, + .readlink = generic_readlink, + .follow_link = sysfs_follow_link, + .put_link = sysfs_put_link, + .setattr = sysfs_setattr, + .getattr = sysfs_getattr, + .permission = sysfs_permission, };