1 files changed, 201 insertions, 0 deletions

diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c
new file mode 100644
index 000000000000..be177f702acb
--- /dev/null
+++ b/fs/proc/namespaces.c
@@ -0,0 +1,201 @@
+#include <linux/proc_fs.h>
+#include <linux/nsproxy.h>
+#include <linux/sched.h>
+#include <linux/ptrace.h>
+#include <linux/fs_struct.h>
+#include <linux/mount.h>
+#include <linux/path.h>
+#include <linux/namei.h>
+#include <linux/file.h>
+#include <linux/utsname.h>
+#include <net/net_namespace.h>
+#include <linux/mnt_namespace.h>
+#include <linux/ipc_namespace.h>
+#include <linux/pid_namespace.h>
+#include "internal.h"
+
+
+static const struct proc_ns_operations *ns_entries[] = {
+#ifdef CONFIG_NET_NS
+        &netns_operations,
+#endif
+#ifdef CONFIG_UTS_NS
+        &utsns_operations,
+#endif
+#ifdef CONFIG_IPC_NS
+        &ipcns_operations,
+#endif
+};
+
+static const struct file_operations ns_file_operations = {
+        .llseek         = no_llseek,
+};
+
+static struct dentry *proc_ns_instantiate(struct inode *dir,
+        struct dentry *dentry, struct task_struct *task, const void *ptr)
+{
+        const struct proc_ns_operations *ns_ops = ptr;
+        struct inode *inode;
+        struct proc_inode *ei;
+        struct dentry *error = ERR_PTR(-ENOENT);
+        void *ns;
+
+        inode = proc_pid_make_inode(dir->i_sb, task);
+        if (!inode)
+                goto out;
+
+        ns = ns_ops->get(task);
+        if (!ns)
+                goto out_iput;
+
+        ei = PROC_I(inode);
+        inode->i_mode = S_IFREG|S_IRUSR;
+        inode->i_fop  = &ns_file_operations;
+        ei->ns_ops    = ns_ops;
+        ei->ns        = ns;
+
+        dentry->d_op = &pid_dentry_operations;
+        d_add(dentry, inode);
+        /* Close the race of the process dying before we return the dentry */
+        if (pid_revalidate(dentry, NULL))
+                error = NULL;
+out:
+        return error;
+out_iput:
+        iput(inode);
+        goto out;
+}
+
+static int proc_ns_fill_cache(struct file *filp, void *dirent,
+        filldir_t filldir, struct task_struct *task,
+        const struct proc_ns_operations *ops)
+{
+        return proc_fill_cache(filp, dirent, filldir,
+                                ops->name, strlen(ops->name),
+                                proc_ns_instantiate, task, ops);
+}
+
+static int proc_ns_dir_readdir(struct file *filp, void *dirent,
+                                filldir_t filldir)
+{
+        int i;
+        struct dentry *dentry = filp->f_path.dentry;
+        struct inode *inode = dentry->d_inode;
+        struct task_struct *task = get_proc_task(inode);
+        const struct proc_ns_operations **entry, **last;
+        ino_t ino;
+        int ret;
+
+        ret = -ENOENT;
+        if (!task)
+                goto out_no_task;
+
+        ret = -EPERM;
+        if (!ptrace_may_access(task, PTRACE_MODE_READ))
+                goto out;
+
+        ret = 0;
+        i = filp->f_pos;
+        switch (i) {
+        case 0:
+                ino = inode->i_ino;
+                if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
+                        goto out;
+                i++;
+                filp->f_pos++;
+                /* fall through */
+        case 1:
+                ino = parent_ino(dentry);
+                if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
+                        goto out;
+                i++;
+                filp->f_pos++;
+                /* fall through */
+        default:
+                i -= 2;
+                if (i >= ARRAY_SIZE(ns_entries)) {
+                        ret = 1;
+                        goto out;
+                }
+                entry = ns_entries + i;
+                last = &ns_entries[ARRAY_SIZE(ns_entries) - 1];
+                while (entry <= last) {
+                        if (proc_ns_fill_cache(filp, dirent, filldir,
+                                                task, *entry) < 0)
+                                goto out;
+                        filp->f_pos++;
+                        entry++;
+                }
+        }
+
+        ret = 1;
+out:
+        put_task_struct(task);
+out_no_task:
+        return ret;
+}
+
+const struct file_operations proc_ns_dir_operations = {
+        .read           = generic_read_dir,
+        .readdir        = proc_ns_dir_readdir,
+};
+
+static struct dentry *proc_ns_dir_lookup(struct inode *dir,
+                                struct dentry *dentry, struct nameidata *nd)
+{
+        struct dentry *error;
+        struct task_struct *task = get_proc_task(dir);
+        const struct proc_ns_operations **entry, **last;
+        unsigned int len = dentry->d_name.len;
+
+        error = ERR_PTR(-ENOENT);
+
+        if (!task)
+                goto out_no_task;
+
+        error = ERR_PTR(-EPERM);
+        if (!ptrace_may_access(task, PTRACE_MODE_READ))
+                goto out;
+
+        last = &ns_entries[ARRAY_SIZE(ns_entries) - 1];
+        for (entry = ns_entries; entry <= last; entry++) {
+                if (strlen((*entry)->name) != len)
+                        continue;
+                if (!memcmp(dentry->d_name.name, (*entry)->name, len))
+                        break;
+        }
+        error = ERR_PTR(-ENOENT);
+        if (entry > last)
+                goto out;
+
+        error = proc_ns_instantiate(dir, dentry, task, *entry);
+out:
+        put_task_struct(task);
+out_no_task:
+        return error;
+}
+
+const struct inode_operations proc_ns_dir_inode_operations = {
+        .lookup         = proc_ns_dir_lookup,
+        .getattr        = pid_getattr,
+        .setattr        = proc_setattr,
+};
+
+struct file *proc_ns_fget(int fd)
+{
+        struct file *file;
+
+        file = fget(fd);
+        if (!file)
+                return ERR_PTR(-EBADF);
+
+        if (file->f_op != &ns_file_operations)
+                goto out_invalid;
+
+        return file;
+
+out_invalid:
+        fput(file);
+        return ERR_PTR(-EINVAL);
+}
+