1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (c) 2019 Hammerspace Inc
4 */
5
6 #include <linux/module.h>
7 #include <linux/kobject.h>
8 #include <linux/sysfs.h>
9 #include <linux/fs.h>
10 #include <linux/slab.h>
11 #include <linux/netdevice.h>
12 #include <linux/string.h>
13 #include <linux/nfs_fs.h>
14 #include <linux/rcupdate.h>
15
16 #include "nfs4_fs.h"
17 #include "netns.h"
18 #include "sysfs.h"
19
20 struct kobject *nfs_client_kobj;
21 static struct kset *nfs_client_kset;
22
nfs_netns_object_release(struct kobject * kobj)23 static void nfs_netns_object_release(struct kobject *kobj)
24 {
25 kfree(kobj);
26 }
27
nfs_netns_object_child_ns_type(struct kobject * kobj)28 static const struct kobj_ns_type_operations *nfs_netns_object_child_ns_type(
29 struct kobject *kobj)
30 {
31 return &net_ns_type_operations;
32 }
33
34 static struct kobj_type nfs_netns_object_type = {
35 .release = nfs_netns_object_release,
36 .sysfs_ops = &kobj_sysfs_ops,
37 .child_ns_type = nfs_netns_object_child_ns_type,
38 };
39
nfs_netns_object_alloc(const char * name,struct kset * kset,struct kobject * parent)40 static struct kobject *nfs_netns_object_alloc(const char *name,
41 struct kset *kset, struct kobject *parent)
42 {
43 struct kobject *kobj;
44
45 kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
46 if (kobj) {
47 kobj->kset = kset;
48 if (kobject_init_and_add(kobj, &nfs_netns_object_type,
49 parent, "%s", name) == 0)
50 return kobj;
51 kobject_put(kobj);
52 }
53 return NULL;
54 }
55
nfs_sysfs_init(void)56 int nfs_sysfs_init(void)
57 {
58 nfs_client_kset = kset_create_and_add("nfs", NULL, fs_kobj);
59 if (!nfs_client_kset)
60 return -ENOMEM;
61 nfs_client_kobj = nfs_netns_object_alloc("net", nfs_client_kset, NULL);
62 if (!nfs_client_kobj) {
63 kset_unregister(nfs_client_kset);
64 nfs_client_kset = NULL;
65 return -ENOMEM;
66 }
67 return 0;
68 }
69
nfs_sysfs_exit(void)70 void nfs_sysfs_exit(void)
71 {
72 kobject_put(nfs_client_kobj);
73 kset_unregister(nfs_client_kset);
74 }
75
nfs_netns_identifier_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)76 static ssize_t nfs_netns_identifier_show(struct kobject *kobj,
77 struct kobj_attribute *attr, char *buf)
78 {
79 struct nfs_netns_client *c = container_of(kobj,
80 struct nfs_netns_client,
81 kobject);
82 ssize_t ret;
83
84 rcu_read_lock();
85 ret = scnprintf(buf, PAGE_SIZE, "%s\n", rcu_dereference(c->identifier));
86 rcu_read_unlock();
87 return ret;
88 }
89
90 /* Strip trailing '\n' */
nfs_string_strip(const char * c,size_t len)91 static size_t nfs_string_strip(const char *c, size_t len)
92 {
93 while (len > 0 && c[len-1] == '\n')
94 --len;
95 return len;
96 }
97
nfs_netns_identifier_store(struct kobject * kobj,struct kobj_attribute * attr,const char * buf,size_t count)98 static ssize_t nfs_netns_identifier_store(struct kobject *kobj,
99 struct kobj_attribute *attr,
100 const char *buf, size_t count)
101 {
102 struct nfs_netns_client *c = container_of(kobj,
103 struct nfs_netns_client,
104 kobject);
105 const char *old;
106 char *p;
107 size_t len;
108
109 len = nfs_string_strip(buf, min_t(size_t, count, CONTAINER_ID_MAXLEN));
110 if (!len)
111 return 0;
112 p = kmemdup_nul(buf, len, GFP_KERNEL);
113 if (!p)
114 return -ENOMEM;
115 old = rcu_dereference_protected(xchg(&c->identifier, (char __rcu *)p), 1);
116 if (old) {
117 synchronize_rcu();
118 kfree(old);
119 }
120 return count;
121 }
122
nfs_netns_client_release(struct kobject * kobj)123 static void nfs_netns_client_release(struct kobject *kobj)
124 {
125 struct nfs_netns_client *c = container_of(kobj,
126 struct nfs_netns_client,
127 kobject);
128
129 kfree(rcu_dereference_raw(c->identifier));
130 kfree(c);
131 }
132
nfs_netns_client_namespace(struct kobject * kobj)133 static const void *nfs_netns_client_namespace(struct kobject *kobj)
134 {
135 return container_of(kobj, struct nfs_netns_client, kobject)->net;
136 }
137
138 static struct kobj_attribute nfs_netns_client_id = __ATTR(identifier,
139 0644, nfs_netns_identifier_show, nfs_netns_identifier_store);
140
141 static struct attribute *nfs_netns_client_attrs[] = {
142 &nfs_netns_client_id.attr,
143 NULL,
144 };
145
146 static struct kobj_type nfs_netns_client_type = {
147 .release = nfs_netns_client_release,
148 .default_attrs = nfs_netns_client_attrs,
149 .sysfs_ops = &kobj_sysfs_ops,
150 .namespace = nfs_netns_client_namespace,
151 };
152
nfs_netns_client_alloc(struct kobject * parent,struct net * net)153 static struct nfs_netns_client *nfs_netns_client_alloc(struct kobject *parent,
154 struct net *net)
155 {
156 struct nfs_netns_client *p;
157
158 p = kzalloc(sizeof(*p), GFP_KERNEL);
159 if (p) {
160 p->net = net;
161 p->kobject.kset = nfs_client_kset;
162 if (kobject_init_and_add(&p->kobject, &nfs_netns_client_type,
163 parent, "nfs_client") == 0)
164 return p;
165 kobject_put(&p->kobject);
166 }
167 return NULL;
168 }
169
nfs_netns_sysfs_setup(struct nfs_net * netns,struct net * net)170 void nfs_netns_sysfs_setup(struct nfs_net *netns, struct net *net)
171 {
172 struct nfs_netns_client *clp;
173
174 clp = nfs_netns_client_alloc(nfs_client_kobj, net);
175 if (clp) {
176 netns->nfs_client = clp;
177 kobject_uevent(&clp->kobject, KOBJ_ADD);
178 }
179 }
180
nfs_netns_sysfs_destroy(struct nfs_net * netns)181 void nfs_netns_sysfs_destroy(struct nfs_net *netns)
182 {
183 struct nfs_netns_client *clp = netns->nfs_client;
184
185 if (clp) {
186 kobject_uevent(&clp->kobject, KOBJ_REMOVE);
187 kobject_del(&clp->kobject);
188 kobject_put(&clp->kobject);
189 netns->nfs_client = NULL;
190 }
191 }
192
