minix/servers/vfs/device.c

   1 /*
   2  * This file contains a number of device-type independent device routines.
   3  *
   4  * The entry points in this file are:
   5  *   do_ioctl:          perform the IOCTL system call
   6  *   make_ioctl_grant:  make a grant for an IOCTL request to a device
   7  */
   8
   9 #include "fs.h"
  10 #include "vnode.h"
  11 #include "file.h"
  12 #include <sys/ioctl.h>
  13
  14 /*
  15  * Perform the ioctl(2) system call.
  16  */
  17 int
  18 do_ioctl(void)
  19 {
  20         unsigned long request;
  21         struct filp *f;
  22         register struct vnode *vp;
  23         vir_bytes arg;
  24         int r, fd;
  25
  26         fd = job_m_in.m_lc_vfs_ioctl.fd;
  27         request = job_m_in.m_lc_vfs_ioctl.req;
  28         arg = (vir_bytes)job_m_in.m_lc_vfs_ioctl.arg;
  29
  30         if ((f = get_filp(fd, VNODE_READ)) == NULL)
  31                 return(err_code);
  32         vp = f->filp_vno;               /* get vnode pointer */
  33
  34         switch (vp->v_mode & S_IFMT) {
  35         case S_IFBLK:
  36                 f->filp_ioctl_fp = fp;
  37
  38                 r = bdev_ioctl(vp->v_sdev, who_e, request, arg);
  39
  40                 f->filp_ioctl_fp = NULL;
  41                 break;
  42
  43         case S_IFCHR:
  44                 r = cdev_io(CDEV_IOCTL, vp->v_sdev, who_e, arg, 0, request,
  45                     f->filp_flags);
  46                 break;
  47
  48         case S_IFSOCK:
  49                 r = sdev_ioctl(vp->v_sdev, request, arg, f->filp_flags);
  50                 break;
  51
  52         default:
  53                 r = ENOTTY;
  54         }
  55
  56         unlock_filp(f);
  57
  58         return r;
  59 }
  60
  61 /*
  62  * Create a magic grant for the given IOCTL request.
  63  */
  64 cp_grant_id_t
  65 make_ioctl_grant(endpoint_t driver_e, endpoint_t user_e, vir_bytes buf,
  66         unsigned long request)
  67 {
  68         cp_grant_id_t grant;
  69         int access;
  70         size_t size;
  71
  72         /*
  73          * For IOCTLs, the bytes parameter contains the IOCTL request.
  74          * This request encodes the requested access method and buffer size.
  75          */
  76         access = 0;
  77         if (_MINIX_IOCTL_IOR(request)) access |= CPF_WRITE;
  78         if (_MINIX_IOCTL_IOW(request)) access |= CPF_READ;
  79         if (_MINIX_IOCTL_BIG(request))
  80                 size = _MINIX_IOCTL_SIZE_BIG(request);
  81         else
  82                 size = _MINIX_IOCTL_SIZE(request);
  83
  84         /*
  85          * Grant access to the buffer even if no I/O happens with the ioctl,
  86          * although now that we no longer identify responses based on grants,
  87          * this is not strictly necessary.
  88          */
  89         grant = cpf_grant_magic(driver_e, user_e, buf, size, access);
  90
  91         if (!GRANT_VALID(grant))
  92                 panic("VFS: cpf_grant_magic failed");
  93
  94         return grant;
  95 }