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/sunrpc/svc.h>
11#include <linux/nfsd/nfsd.h>
12#include <linux/nfsd/syscall.h>
13#include <linux/cred.h>
14#include <linux/sched.h>
15#include <linux/linkage.h>
16#include <linux/namei.h>
17#include <linux/mount.h>
18#include <linux/syscalls.h>
19#include <asm/uaccess.h>
20
21/*
22 * open a file on nfsd fs
23 */
24
25static struct file *do_open(char *name, int flags)
26{
27    struct nameidata nd;
28    struct vfsmount *mnt;
29    int error;
30
31    mnt = do_kern_mount("nfsd", 0, "nfsd", NULL);
32    if (IS_ERR(mnt))
33        return (struct file *)mnt;
34
35    error = vfs_path_lookup(mnt->mnt_root, mnt, name, 0, &nd);
36    mntput(mnt); /* drop do_kern_mount reference */
37    if (error)
38        return ERR_PTR(error);
39
40    if (flags == O_RDWR)
41        error = may_open(&nd.path, MAY_READ|MAY_WRITE,
42                       FMODE_READ|FMODE_WRITE);
43    else
44        error = may_open(&nd.path, MAY_WRITE, FMODE_WRITE);
45
46    if (!error)
47        return dentry_open(nd.path.dentry, nd.path.mnt, flags,
48                   current_cred());
49
50    path_put(&nd.path);
51    return ERR_PTR(error);
52}
53
54static struct {
55    char *name; int wsize; int rsize;
56} map[] = {
57    [NFSCTL_SVC] = {
58        .name = ".svc",
59        .wsize = sizeof(struct nfsctl_svc)
60    },
61    [NFSCTL_ADDCLIENT] = {
62        .name = ".add",
63        .wsize = sizeof(struct nfsctl_client)
64    },
65    [NFSCTL_DELCLIENT] = {
66        .name = ".del",
67        .wsize = sizeof(struct nfsctl_client)
68    },
69    [NFSCTL_EXPORT] = {
70        .name = ".export",
71        .wsize = sizeof(struct nfsctl_export)
72    },
73    [NFSCTL_UNEXPORT] = {
74        .name = ".unexport",
75        .wsize = sizeof(struct nfsctl_export)
76    },
77    [NFSCTL_GETFD] = {
78        .name = ".getfd",
79        .wsize = sizeof(struct nfsctl_fdparm),
80        .rsize = NFS_FHSIZE
81    },
82    [NFSCTL_GETFS] = {
83        .name = ".getfs",
84        .wsize = sizeof(struct nfsctl_fsparm),
85        .rsize = sizeof(struct knfsd_fh)
86    },
87};
88
89SYSCALL_DEFINE3(nfsservctl, int, cmd, struct nfsctl_arg __user *, arg,
90        void __user *, res)
91{
92    struct file *file;
93    void __user *p = &arg->u;
94    int version;
95    int err;
96
97    if (copy_from_user(&version, &arg->ca_version, sizeof(int)))
98        return -EFAULT;
99
100    if (version != NFSCTL_VERSION)
101        return -EINVAL;
102
103    if (cmd < 0 || cmd >= ARRAY_SIZE(map) || !map[cmd].name)
104        return -EINVAL;
105
106    file = do_open(map[cmd].name, map[cmd].rsize ? O_RDWR : O_WRONLY);
107    if (IS_ERR(file))
108        return PTR_ERR(file);
109    err = file->f_op->write(file, p, map[cmd].wsize, &file->f_pos);
110    if (err >= 0 && map[cmd].rsize)
111        err = file->f_op->read(file, res, map[cmd].rsize, &file->f_pos);
112    if (err >= 0)
113        err = 0;
114    fput(file);
115    return err;
116}
117

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