minix/servers/vfs/dmap.c
David van Moolenbroek b4d909d415 Split block/character protocols and libdriver
This patch separates the character and block driver communication
protocols. The old character protocol remains the same, but a new
block protocol is introduced. The libdriver library is replaced by
two new libraries: libchardriver and libblockdriver. Their exposed
API, and drivers that use them, have been updated accordingly.
Together, libbdev and libblockdriver now completely abstract away
the message format used by the block protocol. As the memory driver
is both a character and a block device driver, it now implements its
own message loop.

The most important semantic change made to the block protocol is that
it is no longer possible to return both partial results and an error
for a single transfer. This simplifies the interaction between the
caller and the driver, as the I/O vector no longer needs to be copied
back. Also, drivers are now no longer supposed to decide based on the
layout of the I/O vector when a transfer should be cut short. Put
simply, transfers are now supposed to either succeed completely, or
result in an error.

After this patch, the state of the various pieces is as follows:
- block protocol: stable
- libbdev API: stable for synchronous communication
- libblockdriver API: needs slight revision (the drvlib/partition API
  in particular; the threading API will also change shortly)
- character protocol: needs cleanup
- libchardriver API: needs cleanup accordingly
- driver restarts: largely unsupported until endpoint changes are
  reintroduced

As a side effect, this patch eliminates several bugs, hacks, and gcc
-Wall and -W warnings all over the place. It probably introduces a
few new ones, too.

Update warning: this patch changes the protocol between MFS and disk
drivers, so in order to use old/new images, the MFS from the ramdisk
must be used to mount all file systems.
2011-11-23 14:06:37 +01:00

265 lines
6.8 KiB
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"
#define NC(x) (NR_CTRLRS >= (x))
/* The order of the entries in the table determines the mapping between major
* device numbers and device drivers. Character and block devices
* can be intermixed at random. The ordering determines the device numbers in
* /dev. Note that the major device numbers used in /dev are NOT the same as
* the process numbers of the device drivers. See <minix/dmap.h> for mappings.
*/
struct dmap dmap[NR_DEVICES];
#define DT_EMPTY { no_dev, no_dev_io, NONE, "", 0, STYLE_NDEV, NULL }
/*===========================================================================*
* do_mapdriver *
*===========================================================================*/
PUBLIC int do_mapdriver()
{
int r, flags, major;
endpoint_t endpoint;
vir_bytes label_vir;
size_t label_len;
char label[LABEL_MAX];
/* Only RS can map drivers. */
if (who_e != RS_PROC_NR)
{
printf("vfs: unauthorized call of do_mapdriver by proc %d\n",
who_e);
return(EPERM);
}
/* 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_label_endpt(label, &endpoint);
if (r != OK)
{
printf("vfs:do_mapdriver: ds doesn't know '%s'\n", label);
return EINVAL;
}
/* Try to update device mapping. */
major= m_in.md_major;
flags= m_in.md_flags;
r= map_driver(label, major, endpoint, m_in.md_style, flags);
return(r);
}
/*===========================================================================*
* map_driver *
*===========================================================================*/
PUBLIC int map_driver(label, major, proc_nr_e, style, flags)
const 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 flags; /* device flags */
{
/* Set a new device driver mapping in the dmap table.
* If the proc_nr is set to NONE, we're supposed to unmap it.
*/
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(proc_nr_e == NONE) {
dp->dmap_opcl = no_dev;
dp->dmap_io = no_dev_io;
dp->dmap_driver = NONE;
dp->dmap_flags = flags;
return(OK);
}
/* Check process number of new driver if requested. */
if (! (flags & DRV_FORCED))
{
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("map_driver: label too long: %d", len);
strcpy(dp->dmap_label, label);
}
/* Try to update the entry. */
switch (style) {
case STYLE_DEV:
dp->dmap_opcl = gen_opcl;
dp->dmap_io = gen_io;
break;
case STYLE_DEVA:
dp->dmap_opcl = gen_opcl;
dp->dmap_io = asyn_io;
break;
case STYLE_TTY:
dp->dmap_opcl = tty_opcl;
dp->dmap_io = gen_io;
break;
case STYLE_CTTY:
dp->dmap_opcl = ctty_opcl;
dp->dmap_io = ctty_io;
break;
case STYLE_CLONE:
case STYLE_CLONE_A:
dp->dmap_opcl = clone_opcl;
dp->dmap_io = gen_io;
break;
default:
return(EINVAL);
}
dp->dmap_driver = proc_nr_e;
dp->dmap_flags = flags;
dp->dmap_style = style;
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;
}
/*===========================================================================*
* map_service *
*===========================================================================*/
PUBLIC int map_service(struct rprocpub *rpub)
{
/* Map a new service by storing its device driver properties. */
int r;
/* Not a driver, nothing more to do. */
if(!rpub->dev_nr) {
return OK;
}
/* Map driver. */
r = map_driver(rpub->label, rpub->dev_nr, rpub->endpoint,
rpub->dev_style, rpub->dev_flags);
if(r != OK) {
return r;
}
/* If driver has two major numbers associated, also map the other one. */
if(rpub->dev_style2 != STYLE_NDEV) {
r = map_driver(rpub->label, rpub->dev_nr+1, rpub->endpoint,
rpub->dev_style2, rpub->dev_flags);
if(r != OK) {
return r;
}
}
return OK;
}
/*===========================================================================*
* build_dmap *
*===========================================================================*/
PUBLIC void build_dmap()
{
/* Initialize the table with empty device <-> driver mappings. */
int i;
struct dmap dmap_default = DT_EMPTY;
for (i=0; i<NR_DEVICES; i++) {
dmap[i] = dmap_default;
}
}
/*===========================================================================*
* 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 is_blk)
{
int i;
for (i=0; i<NR_DEVICES; i++) {
if(dmap[i].dmap_driver != NONE
&& dmap[i].dmap_driver == proc_e) {
if (is_blk)
bdev_up(i);
else
cdev_up(i);
}
}
}
/*===========================================================================*
* get_dmap *
*===========================================================================*/
PUBLIC struct dmap *get_dmap(endpoint_t proc_e)
{
/* See if 'proc_e' endpoint belongs to a valid dmap entry. If so, return a
* pointer */
int major;
for (major = 0; major < NR_DEVICES; major++)
if (dmap_driver_match(proc_e, major))
return(&dmap[major]);
return(NULL);
}