drivers/media/dvb/dvb-core/dvb_functions.c

   1 #include <linux/errno.h>
   2 #include <linux/fs.h>
   3 #include <linux/string.h>
   4 #include <linux/module.h>
   5 #include <linux/ioctl.h>
   6 #include <linux/slab.h>
   7 #include <linux/smp_lock.h>
   8 #include <asm/uaccess.h>
   9
  10 void dvb_kernel_thread_setup (const char *thread_name)
  11 {
  12         lock_kernel ();
  13
  14         daemonize (thread_name);
  15
  16         sigfillset (&current->blocked);
  17
  18         unlock_kernel ();
  19 }
  20
  21 /* if the miracle happens and "generic_usercopy()" is included into
  22    the kernel, then this can vanish. please don't make the mistake and
  23    define this as video_usercopy(). this will introduce a dependecy
  24    to the v4l "videodev.o" module, which is unnecessary for some
  25    cards (ie. the budget dvb-cards don't need the v4l module...) */
  26 int dvb_usercopy(struct inode *inode, struct file *file,
  27                      unsigned int cmd, unsigned long arg,
  28                      int (*func)(struct inode *inode, struct file *file,
  29                      unsigned int cmd, void *arg))
  30 {
  31         char    sbuf[128];
  32         void    *mbuf = NULL;
  33         void    *parg = NULL;
  34         int     err  = -EINVAL;
  35
  36         /*  Copy arguments into temp kernel buffer  */
  37         switch (_IOC_DIR(cmd)) {
  38         case _IOC_NONE:
  39                 /*
  40                  * For this command, the pointer is actually an integer
  41                  * argument.
  42                  */
  43                 parg = (void *) arg;
  44                 break;
  45         case _IOC_READ: /* some v4l ioctls are marked wrong ... */
  46         case _IOC_WRITE:
  47         case (_IOC_WRITE | _IOC_READ):
  48                 if (_IOC_SIZE(cmd) <= sizeof(sbuf)) {
  49                         parg = sbuf;
  50                 } else {
  51                         /* too big to allocate from stack */
  52                         mbuf = kmalloc(_IOC_SIZE(cmd),GFP_KERNEL);
  53                         if (NULL == mbuf)
  54                                 return -ENOMEM;
  55                         parg = mbuf;
  56                 }
  57
  58                 err = -EFAULT;
  59                 if (copy_from_user(parg, (void __user *)arg, _IOC_SIZE(cmd)))
  60                         goto out;
  61                 break;
  62         }
  63
  64         /* call driver */
  65         if ((err = func(inode, file, cmd, parg)) == -ENOIOCTLCMD)
  66                 err = -EINVAL;
  67
  68         if (err < 0)
  69                 goto out;
  70
  71         /*  Copy results into user buffer  */
  72         switch (_IOC_DIR(cmd))
  73         {
  74         case _IOC_READ:
  75         case (_IOC_WRITE | _IOC_READ):
  76                 if (copy_to_user((void __user *)arg, parg, _IOC_SIZE(cmd)))
  77                         err = -EFAULT;
  78                 break;
  79         }
  80
  81 out:
  82         if (mbuf)
  83                 kfree(mbuf);
  84
  85         return err;
  86 }
  87
  88 EXPORT_SYMBOL(dvb_usercopy);
  89 EXPORT_SYMBOL(dvb_kernel_thread_setup);