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 vfsmount *mnt;
26    struct file *file;
27
28    mnt = do_kern_mount("nfsd", 0, "nfsd", NULL);
29    if (IS_ERR(mnt))
30        return (struct file *)mnt;
31
32    file = file_open_root(mnt->mnt_root, mnt, name, flags);
33
34    mntput(mnt); /* drop do_kern_mount reference */
35    return file;
36}
37
38static struct {
39    char *name; int wsize; int rsize;
40} map[] = {
41    [NFSCTL_SVC] = {
42        .name = ".svc",
43        .wsize = sizeof(struct nfsctl_svc)
44    },
45    [NFSCTL_ADDCLIENT] = {
46        .name = ".add",
47        .wsize = sizeof(struct nfsctl_client)
48    },
49    [NFSCTL_DELCLIENT] = {
50        .name = ".del",
51        .wsize = sizeof(struct nfsctl_client)
52    },
53    [NFSCTL_EXPORT] = {
54        .name = ".export",
55        .wsize = sizeof(struct nfsctl_export)
56    },
57    [NFSCTL_UNEXPORT] = {
58        .name = ".unexport",
59        .wsize = sizeof(struct nfsctl_export)
60    },
61    [NFSCTL_GETFD] = {
62        .name = ".getfd",
63        .wsize = sizeof(struct nfsctl_fdparm),
64        .rsize = NFS_FHSIZE
65    },
66    [NFSCTL_GETFS] = {
67        .name = ".getfs",
68        .wsize = sizeof(struct nfsctl_fsparm),
69        .rsize = sizeof(struct knfsd_fh)
70    },
71};
72
73SYSCALL_DEFINE3(nfsservctl, int, cmd, struct nfsctl_arg __user *, arg,
74        void __user *, res)
75{
76    struct file *file;
77    void __user *p = &arg->u;
78    int version;
79    int err;
80
81    if (copy_from_user(&version, &arg->ca_version, sizeof(int)))
82        return -EFAULT;
83
84    if (version != NFSCTL_VERSION)
85        return -EINVAL;
86
87    if (cmd < 0 || cmd >= ARRAY_SIZE(map) || !map[cmd].name)
88        return -EINVAL;
89
90    file = do_open(map[cmd].name, map[cmd].rsize ? O_RDWR : O_WRONLY);
91    if (IS_ERR(file))
92        return PTR_ERR(file);
93    err = file->f_op->write(file, p, map[cmd].wsize, &file->f_pos);
94    if (err >= 0 && map[cmd].rsize)
95        err = file->f_op->read(file, res, map[cmd].rsize, &file->f_pos);
96    if (err >= 0)
97        err = 0;
98    fput(file);
99    return err;
100}
101

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