Merge tag 'v3.3.7' into 3.3/master
[zen-stable.git] / fs / proc / namespaces.c
blob3551f1f839eb163801a22bfb1243211ee41b404f
1 #include <linux/proc_fs.h>
2 #include <linux/nsproxy.h>
3 #include <linux/sched.h>
4 #include <linux/ptrace.h>
5 #include <linux/fs_struct.h>
6 #include <linux/mount.h>
7 #include <linux/path.h>
8 #include <linux/namei.h>
9 #include <linux/file.h>
10 #include <linux/utsname.h>
11 #include <net/net_namespace.h>
12 #include <linux/ipc_namespace.h>
13 #include <linux/pid_namespace.h>
14 #include "internal.h"
17 static const struct proc_ns_operations *ns_entries[] = {
18 #ifdef CONFIG_NET_NS
19 &netns_operations,
20 #endif
21 #ifdef CONFIG_UTS_NS
22 &utsns_operations,
23 #endif
24 #ifdef CONFIG_IPC_NS
25 &ipcns_operations,
26 #endif
29 static const struct file_operations ns_file_operations = {
30 .llseek = no_llseek,
33 static struct dentry *proc_ns_instantiate(struct inode *dir,
34 struct dentry *dentry, struct task_struct *task, const void *ptr)
36 const struct proc_ns_operations *ns_ops = ptr;
37 struct inode *inode;
38 struct proc_inode *ei;
39 struct dentry *error = ERR_PTR(-ENOENT);
40 void *ns;
42 inode = proc_pid_make_inode(dir->i_sb, task);
43 if (!inode)
44 goto out;
46 ns = ns_ops->get(task);
47 if (!ns)
48 goto out_iput;
50 ei = PROC_I(inode);
51 inode->i_mode = S_IFREG|S_IRUSR;
52 inode->i_fop = &ns_file_operations;
53 ei->ns_ops = ns_ops;
54 ei->ns = ns;
56 d_set_d_op(dentry, &pid_dentry_operations);
57 d_add(dentry, inode);
58 /* Close the race of the process dying before we return the dentry */
59 if (pid_revalidate(dentry, NULL))
60 error = NULL;
61 out:
62 return error;
63 out_iput:
64 iput(inode);
65 goto out;
68 static int proc_ns_fill_cache(struct file *filp, void *dirent,
69 filldir_t filldir, struct task_struct *task,
70 const struct proc_ns_operations *ops)
72 return proc_fill_cache(filp, dirent, filldir,
73 ops->name, strlen(ops->name),
74 proc_ns_instantiate, task, ops);
77 static int proc_ns_dir_readdir(struct file *filp, void *dirent,
78 filldir_t filldir)
80 int i;
81 struct dentry *dentry = filp->f_path.dentry;
82 struct inode *inode = dentry->d_inode;
83 struct task_struct *task = get_proc_task(inode);
84 const struct proc_ns_operations **entry, **last;
85 ino_t ino;
86 int ret;
88 ret = -ENOENT;
89 if (!task)
90 goto out_no_task;
92 ret = -EPERM;
93 if (!ptrace_may_access(task, PTRACE_MODE_READ))
94 goto out;
96 ret = 0;
97 i = filp->f_pos;
98 switch (i) {
99 case 0:
100 ino = inode->i_ino;
101 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
102 goto out;
103 i++;
104 filp->f_pos++;
105 /* fall through */
106 case 1:
107 ino = parent_ino(dentry);
108 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
109 goto out;
110 i++;
111 filp->f_pos++;
112 /* fall through */
113 default:
114 i -= 2;
115 if (i >= ARRAY_SIZE(ns_entries)) {
116 ret = 1;
117 goto out;
119 entry = ns_entries + i;
120 last = &ns_entries[ARRAY_SIZE(ns_entries) - 1];
121 while (entry <= last) {
122 if (proc_ns_fill_cache(filp, dirent, filldir,
123 task, *entry) < 0)
124 goto out;
125 filp->f_pos++;
126 entry++;
130 ret = 1;
131 out:
132 put_task_struct(task);
133 out_no_task:
134 return ret;
137 const struct file_operations proc_ns_dir_operations = {
138 .read = generic_read_dir,
139 .readdir = proc_ns_dir_readdir,
142 static struct dentry *proc_ns_dir_lookup(struct inode *dir,
143 struct dentry *dentry, struct nameidata *nd)
145 struct dentry *error;
146 struct task_struct *task = get_proc_task(dir);
147 const struct proc_ns_operations **entry, **last;
148 unsigned int len = dentry->d_name.len;
150 error = ERR_PTR(-ENOENT);
152 if (!task)
153 goto out_no_task;
155 error = ERR_PTR(-EPERM);
156 if (!ptrace_may_access(task, PTRACE_MODE_READ))
157 goto out;
159 last = &ns_entries[ARRAY_SIZE(ns_entries) - 1];
160 for (entry = ns_entries; entry <= last; entry++) {
161 if (strlen((*entry)->name) != len)
162 continue;
163 if (!memcmp(dentry->d_name.name, (*entry)->name, len))
164 break;
166 error = ERR_PTR(-ENOENT);
167 if (entry > last)
168 goto out;
170 error = proc_ns_instantiate(dir, dentry, task, *entry);
171 out:
172 put_task_struct(task);
173 out_no_task:
174 return error;
177 const struct inode_operations proc_ns_dir_inode_operations = {
178 .lookup = proc_ns_dir_lookup,
179 .getattr = pid_getattr,
180 .setattr = proc_setattr,
183 struct file *proc_ns_fget(int fd)
185 struct file *file;
187 file = fget(fd);
188 if (!file)
189 return ERR_PTR(-EBADF);
191 if (file->f_op != &ns_file_operations)
192 goto out_invalid;
194 return file;
196 out_invalid:
197 fput(file);
198 return ERR_PTR(-EINVAL);