Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  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/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 
 23 static 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,MAY_READ|MAY_WRITE,FMODE_READ|FMODE_WRITE);
 40         else
 41                 error = may_open(&nd, MAY_WRITE, FMODE_WRITE);
 42 
 43         if (!error)
 44                 return dentry_open(nd.path.dentry, nd.path.mnt, flags);
 45 
 46         path_put(&nd.path);
 47         return ERR_PTR(error);
 48 }
 49 
 50 static struct {
 51         char *name; int wsize; int rsize;
 52 } map[] = {
 53         [NFSCTL_SVC] = {
 54                 .name   = ".svc",
 55                 .wsize  = sizeof(struct nfsctl_svc)
 56         },
 57         [NFSCTL_ADDCLIENT] = {
 58                 .name   = ".add",
 59                 .wsize  = sizeof(struct nfsctl_client)
 60         },
 61         [NFSCTL_DELCLIENT] = {
 62                 .name   = ".del",
 63                 .wsize  = sizeof(struct nfsctl_client)
 64         },
 65         [NFSCTL_EXPORT] = {
 66                 .name   = ".export",
 67                 .wsize  = sizeof(struct nfsctl_export)
 68         },
 69         [NFSCTL_UNEXPORT] = {
 70                 .name   = ".unexport",
 71                 .wsize  = sizeof(struct nfsctl_export)
 72         },
 73         [NFSCTL_GETFD] = {
 74                 .name   = ".getfd",
 75                 .wsize  = sizeof(struct nfsctl_fdparm),
 76                 .rsize  = NFS_FHSIZE
 77         },
 78         [NFSCTL_GETFS] = {
 79                 .name   = ".getfs",
 80                 .wsize  = sizeof(struct nfsctl_fsparm),
 81                 .rsize  = sizeof(struct knfsd_fh)
 82         },
 83 };
 84 
 85 long
 86 asmlinkage sys_nfsservctl(int cmd, struct nfsctl_arg __user *arg, void __user *res)
 87 {
 88         struct file *file;
 89         void __user *p = &arg->u;
 90         int version;
 91         int err;
 92 
 93         if (copy_from_user(&version, &arg->ca_version, sizeof(int)))
 94                 return -EFAULT;
 95 
 96         if (version != NFSCTL_VERSION)
 97                 return -EINVAL;
 98 
 99         if (cmd < 0 || cmd >= ARRAY_SIZE(map) || !map[cmd].name)
100                 return -EINVAL;
101 
102         file = do_open(map[cmd].name, map[cmd].rsize ? O_RDWR : O_WRONLY);      
103         if (IS_ERR(file))
104                 return PTR_ERR(file);
105         err = file->f_op->write(file, p, map[cmd].wsize, &file->f_pos);
106         if (err >= 0 && map[cmd].rsize)
107                 err = file->f_op->read(file, res, map[cmd].rsize, &file->f_pos);
108         if (err >= 0)
109                 err = 0;
110         fput(file);
111         return err;
112 }
113 
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