minix/servers/vfs/dmap.c

/* This file contains the table with device <-> driver mappings. It also
 * contains some routines to dynamically add and/ or remove device drivers
 * or change mappings.  
 */

#include "fs.h"
#include "fproc.h"
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <unistd.h>
#include <minix/com.h>
#include <minix/ds.h>
#include "param.h"

/* Some devices may or may not be there in the next table. */
#define DT(enable, opcl, io, driver, flags, label) \
  { (enable?(opcl):no_dev), (enable?(io):0), \
  	(enable?(driver):0), (flags), label, FALSE },
#define NC(x) (NR_CTRLRS >= (x))

/* The order of the entries here determines the mapping between major device
 * numbers and tasks.  The first entry (major device 0) is not used.  The
 * next entry is major device 1, etc.  Character and block devices can be
 * intermixed at random.  The ordering determines the device numbers in /dev/.
 * Note that FS knows the device number of /dev/ram/ to load the RAM disk.
 * Also note that the major device numbers used in /dev/ are NOT the same as 
 * the process numbers of the device drivers. 
 */
/*
  Driver enabled     Open/Cls  I/O     Driver #     Flags Device  File
  --------------     --------  ------  -----------  ----- ------  ----       
 */
struct dmap dmap[NR_DEVICES];				/* actual map */ 
PRIVATE struct dmap init_dmap[] = {
  DT(1, no_dev,   0,       0,       	0, "") 	  	/* 0 = not used   */
  DT(1, gen_opcl, gen_io,  MEM_PROC_NR, 0, "memory")        /* 1 = /dev/mem   */
  DT(0, no_dev,   0,       0,           DMAP_MUTABLE, "")   /* 2 = /dev/fd0   */
  DT(0, no_dev,   0,       0,           DMAP_MUTABLE, "")   /* 3 = /dev/c0    */
  DT(1, tty_opcl, gen_io,  TTY_PROC_NR, 0, "")    	 /* 4 = /dev/tty00 */
  DT(1, ctty_opcl,ctty_io, TTY_PROC_NR, 0, "")     	 /* 5 = /dev/tty   */
  DT(0, no_dev,   0,       NONE,	DMAP_MUTABLE, "")	/* 6 = /dev/lp    */

#if (MACHINE == IBM_PC)
  DT(1, no_dev,   0,       0,   	DMAP_MUTABLE, "")   /* 7 = /dev/ip    */
  DT(0, no_dev,   0,       NONE,        DMAP_MUTABLE, "")   /* 8 = /dev/c1    */
  DT(0, 0,        0,       0,   	DMAP_MUTABLE, "")   /* 9 = not used   */
  DT(0, no_dev,   0,       0,           DMAP_MUTABLE, "")   /*10 = /dev/c2    */
  DT(0, no_dev,   0,       0,   	DMAP_MUTABLE, "")   /*11 = /dev/filter*/
  DT(0, no_dev,   0,       NONE,     	DMAP_MUTABLE, "")   /*12 = /dev/c3    */
  DT(0, no_dev,   0,       NONE,	DMAP_MUTABLE, "")   /*13 = /dev/audio */
  DT(0, 0,   	  0,       0,		DMAP_MUTABLE, "")   /*14 = not used   */
  DT(1, gen_opcl, gen_io,  LOG_PROC_NR, 0, "")  	    /*15 = /dev/klog  */
  DT(0, no_dev,   0,       NONE,	DMAP_MUTABLE, "")   /*16 = /dev/random*/
  DT(0, 0,	  0,       0,		DMAP_MUTABLE, "")   /*17 = not used   */
#endif /* IBM_PC */
};

/*===========================================================================*
 *				do_mapdriver		 		     *
 *===========================================================================*/
PUBLIC int do_mapdriver()
{
	int r, force, major, proc_nr_n;
	unsigned long tasknr;
	vir_bytes label_vir;
	size_t label_len;
	char label[16];

	if (!super_user)
	{
		printf("FS: unauthorized call of do_mapdriver by proc %d\n",
			who_e);
		return(EPERM);	/* only su (should be only RS or some drivers)
				 * may call do_mapdriver.
				 */
	}

	/* Get the label */
	label_vir= (vir_bytes)m_in.md_label;
	label_len= m_in.md_label_len;

	if (label_len+1 > sizeof(label))
	{
		printf("vfs:do_mapdriver: label too long\n");
		return EINVAL;
	}

	r= sys_vircopy(who_e, D, label_vir, SELF, D, (vir_bytes)label,
		label_len);
	if (r != OK)
	{
		printf("vfs:do_mapdriver: sys_vircopy failed: %d\n", r);
		return EINVAL;
	}

	label[label_len]= '\0';

	r= ds_retrieve_u32(label, &tasknr);
	if (r != OK)
	{
		printf("vfs:do_mapdriver: ds doesn't know '%s'\n", label);
		return EINVAL;
	}

	if (isokendpt(tasknr, &proc_nr_n) != OK)
	{
		printf("vfs:do_mapdriver: bad endpoint %d\n", tasknr);
		return(EINVAL);
	}

	/* Try to update device mapping. */
	major= m_in.md_major;
	force= m_in.md_force;
	r= map_driver(label, major, tasknr, m_in.md_style, force);
	if (r == OK)
	{
		/* If a driver has completed its exec(), it can be announced
		 * to be up.
		*/
		if(force || fproc[proc_nr_n].fp_execced) {
			dev_up(major);
		} else {
			dmap[major].dmap_flags |= DMAP_BABY;
		}
	}

	return(r);
}

/*===========================================================================*
 *				map_driver		 		     *
 *===========================================================================*/
PUBLIC int map_driver(label, major, proc_nr_e, style, force)
char *label;			/* name of the driver */
int major;			/* major number of the device */
endpoint_t proc_nr_e;		/* process number of the driver */
int style;			/* style of the device */
int force;
{
/* Set a new device driver mapping in the dmap table. Given that correct 
 * arguments are given, this only works if the entry is mutable and the 
 * current driver is not busy.  If the proc_nr is set to NONE, we're supposed
 * to unmap it.
 *
 * Normal error codes are returned so that this function can be used from
 * a system call that tries to dynamically install a new driver.
 */
  int proc_nr_n;
  size_t len;
  struct dmap *dp;

  /* Get pointer to device entry in the dmap table. */
  if (major < 0 || major >= NR_DEVICES) return(ENODEV);
  dp = &dmap[major];		

  /* Check if we're supposed to unmap it. If so, do it even
   * if busy or unmutable, as unmap is called when driver has
   * exited.
   */
 if(proc_nr_e == NONE) {
	dp->dmap_opcl = no_dev;
	dp->dmap_io = no_dev_io;
	dp->dmap_driver = NONE;
	dp->dmap_flags = DMAP_MUTABLE;	/* When gone, not busy or reserved. */
	return(OK);
  }
	
  /* See if updating the entry is allowed. */
  if (! (dp->dmap_flags & DMAP_MUTABLE))  return(EPERM);
  if (dp->dmap_flags & DMAP_BUSY)  return(EBUSY);

  if (!force)
  {
	/* Check process number of new driver. */
	if (isokendpt(proc_nr_e, &proc_nr_n) != OK)
		return(EINVAL);
  }

  if (label != NULL) {
	len= strlen(label);
	if (len+1 > sizeof(dp->dmap_label))
		panic(__FILE__, "map_driver: label too long", len);
	strcpy(dp->dmap_label, label);
  }

  /* Try to update the entry. */
  switch (style) {
  case STYLE_DEV:	dp->dmap_opcl = gen_opcl;	break;
  case STYLE_TTY:	dp->dmap_opcl = tty_opcl;	break;
  case STYLE_CLONE:	dp->dmap_opcl = clone_opcl;	break;
  default:		return(EINVAL);
  }
  dp->dmap_io = gen_io;
  dp->dmap_driver = proc_nr_e;

  if (dp->dmap_async_driver)
	dp->dmap_io= asyn_io;

  return(OK); 
}

/*===========================================================================*
 *				dmap_unmap_by_endpt	 		     *
 *===========================================================================*/
PUBLIC void dmap_unmap_by_endpt(int proc_nr_e)
{
	int i, r;
	for (i=0; i<NR_DEVICES; i++)
	  if(dmap[i].dmap_driver && dmap[i].dmap_driver == proc_nr_e)
	    if((r=map_driver(NULL, i, NONE, 0, 0)) != OK)
		printf("FS: unmap of p %d / d %d failed: %d\n", proc_nr_e,i,r);

	return;

}

/*===========================================================================*
 *				build_dmap		 		     *
 *===========================================================================*/
PUBLIC void build_dmap()
{
/* Initialize the table with all device <-> driver mappings. Then, map  
 * the boot driver to a controller and update the dmap table to that
 * selection. The boot driver and the controller it handles are set at 
 * the boot monitor.  
 */
  int i;
  struct dmap *dp;

  /* Build table with device <-> driver mappings. */
  for (i=0; i<NR_DEVICES; i++) {
      dp = &dmap[i];		
      if (i < sizeof(init_dmap)/sizeof(struct dmap) && 
              init_dmap[i].dmap_opcl != no_dev) {	/* a preset driver */
          dp->dmap_opcl = init_dmap[i].dmap_opcl;
          dp->dmap_io = init_dmap[i].dmap_io;
          dp->dmap_driver = init_dmap[i].dmap_driver;
          dp->dmap_flags = init_dmap[i].dmap_flags;
	  strcpy(dp->dmap_label, init_dmap[i].dmap_label);
	  dp->dmap_async_driver= FALSE;
      } else {						/* no default */
          dp->dmap_opcl = no_dev;
          dp->dmap_io = no_dev_io;
          dp->dmap_driver = NONE;
          dp->dmap_flags = DMAP_MUTABLE;
      }
  }

  dmap[13].dmap_async_driver= TRUE;	/* Audio */
  dmap[15].dmap_async_driver= TRUE;	/* Log */
  dmap[15].dmap_io= asyn_io;
  dmap[16].dmap_async_driver= TRUE;	/* Random */

}

/*===========================================================================*
 *				dmap_driver_match	 		     *
 *===========================================================================*/ 
PUBLIC int dmap_driver_match(endpoint_t proc, int major)
{
	if (major < 0 || major >= NR_DEVICES) return(0);
	if(dmap[major].dmap_driver != NONE && dmap[major].dmap_driver == proc)
		return 1;
	return 0;
}

/*===========================================================================*
 *				dmap_endpt_up		 		     *
 *===========================================================================*/ 
PUBLIC void dmap_endpt_up(int proc_e)
{
	int i;
	for (i=0; i<NR_DEVICES; i++) {
		if(dmap[i].dmap_driver != NONE
			&& dmap[i].dmap_driver == proc_e
			&& (dmap[i].dmap_flags & DMAP_BABY)) {
			dmap[i].dmap_flags &= ~DMAP_BABY;
			dev_up(i);
		}
	}
	return;
}