Root/fs/nfsctl.c

1/*
2 * fs/nfsctl.c
3 *
4 * This should eventually move to userland.
5 *
6 */
7#include <linux/types.h>
8#include <linux/file.h>
9#include <linux/fs.h>
10#include <linux/nfsd/syscall.h>
11#include <linux/cred.h>
12#include <linux/sched.h>
13#include <linux/linkage.h>
14#include <linux/namei.h>
15#include <linux/mount.h>
16#include <linux/syscalls.h>
17#include <asm/uaccess.h>
18
19/*
20 * open a file on nfsd fs
21 */
22
23static struct file *do_open(char *name, int flags)
24{
25    struct nameidata nd;
26    struct vfsmount *mnt;
27    int error;
28
29    mnt = do_kern_mount("nfsd", 0, "nfsd", NULL);
30    if (IS_ERR(mnt))
31        return (struct file *)mnt;
32
33    error = vfs_path_lookup(mnt->mnt_root, mnt, name, 0, &nd);
34    mntput(mnt); /* drop do_kern_mount reference */
35    if (error)
36        return ERR_PTR(error);
37
38    if (flags == O_RDWR)
39        error = may_open(&nd.path, MAY_READ|MAY_WRITE, flags);
40    else
41        error = may_open(&nd.path, MAY_WRITE, flags);
42
43    if (!error)
44        return dentry_open(nd.path.dentry, nd.path.mnt, flags,
45                   current_cred());
46
47    path_put(&nd.path);
48    return ERR_PTR(error);
49}
50
51static struct {
52    char *name; int wsize; int rsize;
53} map[] = {
54    [NFSCTL_SVC] = {
55        .name = ".svc",
56        .wsize = sizeof(struct nfsctl_svc)
57    },
58    [NFSCTL_ADDCLIENT] = {
59        .name = ".add",
60        .wsize = sizeof(struct nfsctl_client)
61    },
62    [NFSCTL_DELCLIENT] = {
63        .name = ".del",
64        .wsize = sizeof(struct nfsctl_client)
65    },
66    [NFSCTL_EXPORT] = {
67        .name = ".export",
68        .wsize = sizeof(struct nfsctl_export)
69    },
70    [NFSCTL_UNEXPORT] = {
71        .name = ".unexport",
72        .wsize = sizeof(struct nfsctl_export)
73    },
74    [NFSCTL_GETFD] = {
75        .name = ".getfd",
76        .wsize = sizeof(struct nfsctl_fdparm),
77        .rsize = NFS_FHSIZE
78    },
79    [NFSCTL_GETFS] = {
80        .name = ".getfs",
81        .wsize = sizeof(struct nfsctl_fsparm),
82        .rsize = sizeof(struct knfsd_fh)
83    },
84};
85
86SYSCALL_DEFINE3(nfsservctl, int, cmd, struct nfsctl_arg __user *, arg,
87        void __user *, res)
88{
89    struct file *file;
90    void __user *p = &arg->u;
91    int version;
92    int err;
93
94    if (copy_from_user(&version, &arg->ca_version, sizeof(int)))
95        return -EFAULT;
96
97    if (version != NFSCTL_VERSION)
98        return -EINVAL;
99
100    if (cmd < 0 || cmd >= ARRAY_SIZE(map) || !map[cmd].name)
101        return -EINVAL;
102
103    file = do_open(map[cmd].name, map[cmd].rsize ? O_RDWR : O_WRONLY);
104    if (IS_ERR(file))
105        return PTR_ERR(file);
106    err = file->f_op->write(file, p, map[cmd].wsize, &file->f_pos);
107    if (err >= 0 && map[cmd].rsize)
108        err = file->f_op->read(file, res, map[cmd].rsize, &file->f_pos);
109    if (err >= 0)
110        err = 0;
111    fput(file);
112    return err;
113}
114

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