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minix/servers/vfs/device.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

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/* When a needed block is not in the cache, it must be fetched from the disk.
* Special character files also require I/O. The routines for these are here.
*
* The entry points in this file are:
* dev_open: open a character device
* dev_reopen: reopen a character device after a driver crash
* dev_close: close a character device
* bdev_open: open a block device
* bdev_close: close a block device
* dev_io: FS does a read or write on a device
* dev_status: FS processes callback request alert
* gen_opcl: generic call to a task to perform an open/close
* gen_io: generic call to a task to perform an I/O operation
* no_dev: open/close processing for devices that don't exist
* no_dev_io: i/o processing for devices that don't exist
* tty_opcl: perform tty-specific processing for open/close
* ctty_opcl: perform controlling-tty-specific processing for open/close
* ctty_io: perform controlling-tty-specific processing for I/O
* do_ioctl: perform the IOCTL system call
* do_setsid: perform the SETSID system call (FS side)
*/
#include "fs.h"
#include <string.h>
#include <fcntl.h>
#include <assert.h>
#include <sys/stat.h>
#include <minix/callnr.h>
#include <minix/com.h>
#include <minix/endpoint.h>
#include <minix/ioctl.h>
#include <minix/u64.h>
#include "file.h"
#include "fproc.h"
#include <minix/vfsif.h>
#include "vnode.h"
#include "vmnt.h"
#include "param.h"
#define ELEMENTS(a) (sizeof(a)/sizeof((a)[0]))
FORWARD _PROTOTYPE( int safe_io_conversion, (endpoint_t, cp_grant_id_t *,
int *, cp_grant_id_t *, int,
endpoint_t *, void **, int *,
vir_bytes, u32_t *) );
FORWARD _PROTOTYPE( void safe_io_cleanup, (cp_grant_id_t, cp_grant_id_t *,
int) );
FORWARD _PROTOTYPE( void restart_reopen, (int maj) );
extern int dmap_size;
PRIVATE int dummyproc;
/*===========================================================================*
* dev_open *
*===========================================================================*/
PUBLIC int dev_open(
dev_t dev, /* device to open */
int proc, /* process to open for */
int flags /* mode bits and flags */
)
{
/* Open a character device. */
int major, r;
struct dmap *dp;
/* Determine the major device number so as to call the device class specific
* open/close routine. (This is the only routine that must check the
* device number for being in range. All others can trust this check.)
*/
major = (dev >> MAJOR) & BYTE;
if (major >= NR_DEVICES) major = 0;
dp = &dmap[major];
if (dp->dmap_driver == NONE) return(ENXIO);
r = (*dp->dmap_opcl)(DEV_OPEN, dev, proc, flags);
return(r);
}
/*===========================================================================*
* dev_reopen *
*===========================================================================*/
PUBLIC int dev_reopen(
dev_t dev, /* device to open */
int filp_no, /* filp to reopen for */
int flags /* mode bits and flags */
)
{
/* Reopen a character device after a failing device driver. */
int major, r;
struct dmap *dp;
/* Determine the major device number call the device class specific
* open/close routine. (This is the only routine that must check the
* device number for being in range. All others can trust this check.)
*/
major = (dev >> MAJOR) & BYTE;
if (major >= NR_DEVICES) major = 0;
dp = &dmap[major];
if (dp->dmap_driver == NONE) return(ENXIO);
r = (*dp->dmap_opcl)(DEV_REOPEN, dev, filp_no, flags);
if (r == OK) panic("OK on reopen from: %d", dp->dmap_driver);
if (r == SUSPEND) r = OK;
return(r);
}
/*===========================================================================*
* dev_close *
*===========================================================================*/
PUBLIC int dev_close(
dev_t dev, /* device to close */
int filp_no
)
{
/* Close a character device. */
int r;
/* See if driver is roughly valid. */
if (dmap[(dev >> MAJOR)].dmap_driver == NONE) return(ENXIO);
r = (*dmap[(dev >> MAJOR) & BYTE].dmap_opcl)(DEV_CLOSE, dev, filp_no, 0);
return(r);
}
/*===========================================================================*
* bdev_open *
*===========================================================================*/
PUBLIC int bdev_open(dev_t dev, int access)
{
/* Open a block device. */
int major;
major = major(dev);
if (major < 0 || major >= NR_DEVICES) return(ENXIO);
if (dmap[major].dmap_driver == NONE) return(ENXIO);
return (*dmap[major].dmap_opcl)(BDEV_OPEN, dev, 0, access);
}
/*===========================================================================*
* bdev_close *
*===========================================================================*/
PUBLIC int bdev_close(dev_t dev)
{
/* Close a block device. */
int major;
major = major(dev);
if (major < 0 || major >= NR_DEVICES) return(ENXIO);
if (dmap[major].dmap_driver == NONE) return(ENXIO);
return (*dmap[major].dmap_opcl)(BDEV_CLOSE, dev, 0, 0);
}
/*===========================================================================*
* bdev_ioctl *
*===========================================================================*/
PRIVATE int bdev_ioctl(dev_t dev, endpoint_t proc_e, int req, void *buf)
{
/* Perform an I/O control operation on a block device. */
struct dmap *dp;
u32_t dummy;
cp_grant_id_t gid;
message dev_mess;
int op, safe, major_dev, minor_dev, vec_grants;
major_dev = major(dev);
minor_dev = minor(dev);
/* Determine task dmap. */
dp = &dmap[major_dev];
if (dp->dmap_driver == NONE) {
printf("VFS: dev_io: no driver for major %d\n", major_dev);
return(ENXIO);
}
/* Set up a grant if necessary. */
op = VFS_DEV_IOCTL;
safe = safe_io_conversion(dp->dmap_driver, &gid, &op, NULL, 0, &proc_e, &buf,
&vec_grants, 0, &dummy);
/* Set up the message passed to the task. */
memset(&dev_mess, 0, sizeof(dev_mess));
dev_mess.m_type = BDEV_IOCTL;
dev_mess.BDEV_MINOR = minor_dev;
dev_mess.BDEV_REQUEST = req;
dev_mess.BDEV_GRANT = gid;
dev_mess.BDEV_ID = 0;
/* Call the task. */
(*dp->dmap_io)(dp->dmap_driver, &dev_mess);
/* Clean up. */
if (safe) safe_io_cleanup(gid, NULL, vec_grants);
if (dp->dmap_driver == NONE) {
printf("VFS: block driver gone!?\n");
return(EIO);
}
/* Return the result. */
return dev_mess.BDEV_STATUS;
}
/*===========================================================================*
* suspended_ep *
*===========================================================================*/
endpoint_t suspended_ep(endpoint_t driver, cp_grant_id_t g)
{
/* A process is suspended on a driver for which FS issued
* a grant. Find out which process it was.
*/
struct fproc *rfp;
for (rfp = &fproc[0]; rfp < &fproc[NR_PROCS]; rfp++) {
if(rfp->fp_pid == PID_FREE) continue;
if(rfp->fp_blocked_on == FP_BLOCKED_ON_OTHER &&
rfp->fp_task == driver && rfp->fp_grant == g)
return rfp->fp_endpoint;
}
return(NONE);
}
/*===========================================================================*
* dev_status *
*===========================================================================*/
PUBLIC void dev_status(message *m)
{
message st;
int d, get_more = 1;
endpoint_t endpt;
for(d = 0; d < NR_DEVICES; d++)
if (dmap[d].dmap_driver != NONE && dmap[d].dmap_driver == m->m_source)
break;
if (d >= NR_DEVICES) return;
if (dmap[d].dmap_style == STYLE_DEVA) {
printf("dev_status: not doing dev_status for async driver %d\n",
m->m_source);
return;
}
do {
int r;
st.m_type = DEV_STATUS;
r = sendrec(m->m_source, &st);
if(r == OK && st.REP_STATUS == ERESTART) r = EDEADEPT;
if (r != OK) {
printf("DEV_STATUS failed to %d: %d\n", m->m_source, r);
if (r == EDEADSRCDST || r == EDEADEPT) return;
panic("couldn't sendrec for DEV_STATUS: %d", r);
}
switch(st.m_type) {
case DEV_REVIVE:
endpt = st.REP_ENDPT;
if(endpt == VFS_PROC_NR) {
endpt = suspended_ep(m->m_source,
st.REP_IO_GRANT);
if(endpt == NONE) {
printf("FS: proc with grant %d"
" from %d not found (revive)\n",
st.REP_IO_GRANT, st.m_source);
continue;
}
}
revive(endpt, st.REP_STATUS);
break;
case DEV_IO_READY:
select_reply2(st.m_source, st.DEV_MINOR,
st.DEV_SEL_OPS);
break;
default:
printf("FS: unrecognized reply %d to "
"DEV_STATUS\n", st.m_type);
/* Fall through. */
case DEV_NO_STATUS:
get_more = 0;
break;
}
} while(get_more);
return;
}
/*===========================================================================*
* safe_io_conversion *
*===========================================================================*/
PRIVATE int safe_io_conversion(driver, gid, op, gids, gids_size,
io_ept, buf, vec_grants, bytes, pos_lo)
endpoint_t driver;
cp_grant_id_t *gid;
int *op;
cp_grant_id_t *gids;
int gids_size;
endpoint_t *io_ept;
void **buf;
int *vec_grants;
vir_bytes bytes;
u32_t *pos_lo;
{
int access = 0, size, j;
iovec_t *v;
static iovec_t new_iovec[NR_IOREQS];
/* Number of grants allocated in vector I/O. */
*vec_grants = 0;
/* Driver can handle it - change request to a safe one. */
*gid = GRANT_INVALID;
switch(*op) {
case VFS_DEV_READ:
case VFS_DEV_WRITE:
/* Change to safe op. */
*op = *op == VFS_DEV_READ ? DEV_READ_S : DEV_WRITE_S;
*gid = cpf_grant_magic(driver, *io_ept, (vir_bytes) *buf, bytes,
*op == DEV_READ_S ? CPF_WRITE : CPF_READ);
if (*gid < 0)
panic("cpf_grant_magic of buffer failed");
break;
case VFS_DEV_GATHER:
case VFS_DEV_SCATTER:
/* Change to safe op. */
*op = *op == VFS_DEV_GATHER ? DEV_GATHER_S : DEV_SCATTER_S;
/* Grant access to my new i/o vector. */
*gid = cpf_grant_direct(driver, (vir_bytes) new_iovec,
bytes * sizeof(iovec_t), CPF_READ|CPF_WRITE);
if (*gid < 0)
panic("cpf_grant_direct of vector failed");
v = (iovec_t *) *buf;
/* Grant access to i/o buffers. */
for(j = 0; j < bytes; j++) {
if(j >= NR_IOREQS) panic("vec too big: %d", bytes);
new_iovec[j].iov_addr =
gids[j] =
cpf_grant_direct(driver, (vir_bytes) v[j].iov_addr, v[j].iov_size,
*op == DEV_GATHER_S ? CPF_WRITE : CPF_READ);
if(!GRANT_VALID(gids[j]))
panic("grant to iovec buf failed");
new_iovec[j].iov_size = v[j].iov_size;
(*vec_grants)++;
}
/* Set user's vector to the new one. */
*buf = new_iovec;
break;
case VFS_DEV_IOCTL:
*pos_lo = *io_ept; /* Old endpoint in POSITION field. */
*op = DEV_IOCTL_S;
if(_MINIX_IOCTL_IOR(m_in.REQUEST)) access |= CPF_WRITE;
if(_MINIX_IOCTL_IOW(m_in.REQUEST)) access |= CPF_READ;
if(_MINIX_IOCTL_BIG(m_in.REQUEST))
size = _MINIX_IOCTL_SIZE_BIG(m_in.REQUEST);
else
size = _MINIX_IOCTL_SIZE(m_in.REQUEST);
/* Do this even if no I/O happens with the ioctl, in
* order to disambiguate requests with DEV_IOCTL_S.
*/
*gid = cpf_grant_magic(driver, *io_ept, (vir_bytes) *buf, size,
access);
if (*gid < 0)
panic("cpf_grant_magic failed (ioctl)");
break;
case VFS_DEV_SELECT:
*op = DEV_SELECT;
break;
default:
panic("safe_io_conversion: unknown operation: %d", *op);
}
/* If we have converted to a safe operation, I/O
* endpoint becomes FS if it wasn't already.
*/
if(GRANT_VALID(*gid)) {
*io_ept = VFS_PROC_NR;
return 1;
}
/* Not converted to a safe operation (because there is no
* copying involved in this operation).
*/
return 0;
}
/*===========================================================================*
* safe_io_cleanup *
*===========================================================================*/
PRIVATE void safe_io_cleanup(gid, gids, gids_size)
cp_grant_id_t gid;
cp_grant_id_t *gids;
int gids_size;
{
/* Free resources (specifically, grants) allocated by safe_io_conversion(). */
int j;
cpf_revoke(gid);
for(j = 0; j < gids_size; j++)
cpf_revoke(gids[j]);
}
/*===========================================================================*
* dev_io *
*===========================================================================*/
PUBLIC int dev_io(
int op, /* DEV_READ, DEV_WRITE, DEV_IOCTL, etc. */
dev_t dev, /* major-minor device number */
int proc_e, /* in whose address space is buf? */
void *buf, /* virtual address of the buffer */
u64_t pos, /* byte position */
int bytes, /* how many bytes to transfer */
int flags, /* special flags, like O_NONBLOCK */
int suspend_reopen /* Just suspend the process */
)
{
/* Read or write from a device. The parameter 'dev' tells which one. */
struct dmap *dp;
u32_t pos_lo, pos_high;
message dev_mess;
cp_grant_id_t gid = GRANT_INVALID;
static cp_grant_id_t gids[NR_IOREQS];
int vec_grants = 0, safe;
void *buf_used;
endpoint_t ioproc;
pos_lo= ex64lo(pos);
pos_high= ex64hi(pos);
/* Determine task dmap. */
dp = &dmap[(dev >> MAJOR) & BYTE];
/* See if driver is roughly valid. */
if (dp->dmap_driver == NONE) {
printf("FS: dev_io: no driver for dev %x\n", dev);
return(ENXIO);
}
if (suspend_reopen) {
/* Suspend user. */
fp->fp_grant = GRANT_INVALID;
fp->fp_ioproc = NONE;
wait_for(dp->dmap_driver);
fp->fp_flags |= SUSP_REOPEN;
return(SUSPEND);
}
if(isokendpt(dp->dmap_driver, &dummyproc) != OK) {
printf("FS: dev_io: old driver for dev %x (%d)\n",dev,dp->dmap_driver);
return(ENXIO);
}
/* By default, these are right. */
dev_mess.USER_ENDPT = proc_e;
dev_mess.ADDRESS = buf;
/* Convert DEV_* to DEV_*_S variants. */
buf_used = buf;
safe = safe_io_conversion(dp->dmap_driver, &gid, &op, gids, NR_IOREQS,
(endpoint_t*) &dev_mess.USER_ENDPT, &buf_used,
&vec_grants, bytes, &pos_lo);
if(buf != buf_used)
panic("dev_io: safe_io_conversion changed buffer");
/* If the safe conversion was done, set the ADDRESS to
* the grant id.
*/
if(safe) dev_mess.IO_GRANT = (char *) gid;
/* Set up the rest of the message passed to task. */
dev_mess.m_type = op;
dev_mess.DEVICE = (dev >> MINOR) & BYTE;
dev_mess.POSITION = pos_lo;
dev_mess.COUNT = bytes;
dev_mess.HIGHPOS = pos_high;
/* This will be used if the i/o is suspended. */
ioproc = dev_mess.USER_ENDPT;
/* Call the task. */
(*dp->dmap_io)(dp->dmap_driver, &dev_mess);
if(dp->dmap_driver == NONE) {
/* Driver has vanished. */
printf("Driver gone?\n");
if(safe) safe_io_cleanup(gid, gids, vec_grants);
return(EIO);
}
/* Task has completed. See if call completed. */
if (dev_mess.REP_STATUS == SUSPEND) {
if(vec_grants > 0) panic("SUSPEND on vectored i/o");
/* fp is uninitialized at init time. */
if(!fp) panic("SUSPEND on NULL fp");
if ((flags & O_NONBLOCK) && !(dp->dmap_style == STYLE_DEVA)) {
/* Not supposed to block. */
dev_mess.m_type = CANCEL;
dev_mess.USER_ENDPT = ioproc;
dev_mess.IO_GRANT = (char *) gid;
/* This R_BIT/W_BIT check taken from suspend()/unpause()
* logic. Mode is expected in the COUNT field.
*/
dev_mess.COUNT = 0;
if (call_nr == READ) dev_mess.COUNT = R_BIT;
else if (call_nr == WRITE) dev_mess.COUNT = W_BIT;
dev_mess.DEVICE = (dev >> MINOR) & BYTE;
(*dp->dmap_io)(dp->dmap_driver, &dev_mess);
if (dev_mess.REP_STATUS == EINTR) dev_mess.REP_STATUS = EAGAIN;
} else {
/* select() will do suspending itself. */
if(op != DEV_SELECT) {
/* Suspend user. */
wait_for(dp->dmap_driver);
}
assert(!GRANT_VALID(fp->fp_grant));
fp->fp_grant = gid; /* revoke this when unsuspended. */
fp->fp_ioproc = ioproc;
if (flags & O_NONBLOCK) {
/* Not supposed to block, send cancel message */
dev_mess.m_type = CANCEL;
dev_mess.USER_ENDPT = ioproc;
dev_mess.IO_GRANT = (char *) gid;
/* This R_BIT/W_BIT check taken from suspend()/unpause()
* logic. Mode is expected in the COUNT field.
*/
dev_mess.COUNT = 0;
if(call_nr == READ) dev_mess.COUNT = R_BIT;
else if(call_nr == WRITE) dev_mess.COUNT = W_BIT;
dev_mess.DEVICE = (dev >> MINOR) & BYTE;
(*dp->dmap_io)(dp->dmap_driver, &dev_mess);
/* Should do something about EINTR -> EAGAIN mapping */
}
return(SUSPEND);
}
}
/* No suspend, or cancelled suspend, so I/O is over and can be cleaned up. */
if(safe) safe_io_cleanup(gid, gids, vec_grants);
return(dev_mess.REP_STATUS);
}
/*===========================================================================*
* gen_opcl *
*===========================================================================*/
PUBLIC int gen_opcl(
int op, /* operation, (B)DEV_OPEN or (B)DEV_CLOSE */
dev_t dev, /* device to open or close */
int proc_e, /* process to open/close for */
int flags /* mode bits and flags */
)
{
/* Called from the dmap struct in table.c on opens & closes of special files.*/
int r, is_bdev;
struct dmap *dp;
message dev_mess;
/* Determine task dmap. */
dp = &dmap[major(dev)];
is_bdev = IS_BDEV_RQ(op);
if (is_bdev) {
memset(&dev_mess, 0, sizeof(dev_mess));
dev_mess.m_type = op;
dev_mess.BDEV_MINOR = minor(dev);
dev_mess.BDEV_ACCESS = flags;
dev_mess.BDEV_ID = 0;
} else {
dev_mess.m_type = op;
dev_mess.DEVICE = minor(dev);
dev_mess.USER_ENDPT = proc_e;
dev_mess.COUNT = flags;
}
if (dp->dmap_driver == NONE) {
printf("FS: gen_opcl: no driver for dev %x\n", dev);
return(ENXIO);
}
/* Call the task. */
r= (*dp->dmap_io)(dp->dmap_driver, &dev_mess);
if (r != OK) return(r);
if (is_bdev)
return(dev_mess.BDEV_STATUS);
else
return(dev_mess.REP_STATUS);
}
/*===========================================================================*
* tty_opcl *
*===========================================================================*/
PUBLIC int tty_opcl(
int op, /* operation, DEV_OPEN or DEV_CLOSE */
dev_t dev, /* device to open or close */
int proc_e, /* process to open/close for */
int flags /* mode bits and flags */
)
{
/* This procedure is called from the dmap struct on tty open/close. */
int r;
register struct fproc *rfp;
assert(!IS_BDEV_RQ(op));
/* Add O_NOCTTY to the flags if this process is not a session leader, or
* if it already has a controlling tty, or if it is someone elses
* controlling tty.
*/
if (!fp->fp_sesldr || fp->fp_tty != 0) {
flags |= O_NOCTTY;
} else {
for (rfp = &fproc[0]; rfp < &fproc[NR_PROCS]; rfp++) {
if(rfp->fp_pid == PID_FREE) continue;
if (rfp->fp_tty == dev) flags |= O_NOCTTY;
}
}
r = gen_opcl(op, dev, proc_e, flags);
/* Did this call make the tty the controlling tty? */
if (r == 1) {
fp->fp_tty = dev;
r = OK;
}
return(r);
}
/*===========================================================================*
* ctty_opcl *
*===========================================================================*/
PUBLIC int ctty_opcl(
int op, /* operation, DEV_OPEN or DEV_CLOSE */
dev_t dev, /* device to open or close */
int proc_e, /* process to open/close for */
int flags /* mode bits and flags */
)
{
/* This procedure is called from the dmap struct in table.c on opening/closing
* /dev/tty, the magic device that translates to the controlling tty.
*/
assert(!IS_BDEV_RQ(op));
return(fp->fp_tty == 0 ? ENXIO : OK);
}
/*===========================================================================*
* pm_setsid *
*===========================================================================*/
PUBLIC void pm_setsid(proc_e)
int proc_e;
{
/* Perform the FS side of the SETSID call, i.e. get rid of the controlling
* terminal of a process, and make the process a session leader.
*/
register struct fproc *rfp;
int slot;
/* Make the process a session leader with no controlling tty. */
okendpt(proc_e, &slot);
rfp = &fproc[slot];
rfp->fp_sesldr = TRUE;
rfp->fp_tty = 0;
}
/*===========================================================================*
* do_ioctl *
*===========================================================================*/
PUBLIC int do_ioctl()
{
/* Perform the ioctl(ls_fd, request, argx) system call (uses m2 fmt). */
int suspend_reopen;
struct filp *f;
register struct vnode *vp;
dev_t dev;
if ((f = get_filp(m_in.ls_fd)) == NULL) return(err_code);
vp = f->filp_vno; /* get vnode pointer */
if ((vp->v_mode & I_TYPE) != I_CHAR_SPECIAL &&
(vp->v_mode & I_TYPE) != I_BLOCK_SPECIAL) return(ENOTTY);
suspend_reopen= (f->filp_state != FS_NORMAL);
dev = (dev_t) vp->v_sdev;
if ((vp->v_mode & I_TYPE) == I_BLOCK_SPECIAL)
return bdev_ioctl(dev, who_e, m_in.REQUEST, m_in.ADDRESS);
return dev_io(VFS_DEV_IOCTL, dev, who_e, m_in.ADDRESS, cvu64(0),
m_in.REQUEST, f->filp_flags, suspend_reopen);
}
/*===========================================================================*
* gen_io *
*===========================================================================*/
PUBLIC int gen_io(task_nr, mess_ptr)
int task_nr; /* which task to call */
message *mess_ptr; /* pointer to message for task */
{
/* All file system I/O ultimately comes down to I/O on major/minor device
* pairs. These lead to calls on the following routines via the dmap table.
*/
int r, status, proc_e, is_bdev;
if(task_nr == SYSTEM) {
printf("VFS: sending %d to SYSTEM\n", mess_ptr->m_type);
}
is_bdev = IS_BDEV_RQ(mess_ptr->m_type);
if (!is_bdev) proc_e = mess_ptr->USER_ENDPT;
for (;;) {
r = sendrec(task_nr, mess_ptr);
if(r == OK) {
if (is_bdev)
status = mess_ptr->BDEV_STATUS;
else
status = mess_ptr->REP_STATUS;
if (status == ERESTART) r = EDEADEPT;
}
if (r != OK) {
if (r == EDEADSRCDST || r == EDEADEPT) {
printf("fs: dead driver %d\n", task_nr);
dmap_unmap_by_endpt(task_nr);
return(r);
}
if (r == ELOCKED) {
printf("fs: ELOCKED talking to %d\n", task_nr);
return(r);
}
panic("call_task: can't send/receive: %d", r);
}
/* Did the process we did the sendrec() for get a result? */
if (!is_bdev &&
mess_ptr->REP_ENDPT != proc_e && VFS_PROC_NR != proc_e) {
printf("fs: strange device reply from %d, type = %d, "
"proc = %d (not %d) (2) ignored\n", mess_ptr->m_source,
mess_ptr->m_type, proc_e, mess_ptr->REP_ENDPT);
return(EIO);
}
if (mess_ptr->m_type == TASK_REPLY ||
IS_DEV_RS(mess_ptr->m_type) ||
IS_BDEV_RS(mess_ptr->m_type) ||
mess_ptr->m_type <= 0) {
break; /* reply */
} else {
nested_dev_call(mess_ptr);
}
}
return(OK);
}
/*===========================================================================*
* asyn_io *
*===========================================================================*/
PUBLIC int asyn_io(task_nr, mess_ptr)
int task_nr; /* which task to call */
message *mess_ptr; /* pointer to message for task */
{
/* All file system I/O ultimately comes down to I/O on major/minor device
* pairs. These lead to calls on the following routines via the dmap table.
*/
int r;
assert(!IS_BDEV_RQ(mess_ptr->m_type));
r = asynsend(task_nr, mess_ptr);
if (r != OK) panic("asyn_io: asynsend failed: %d", r);
/* Fake a SUSPEND */
mess_ptr->REP_STATUS = SUSPEND;
return(OK);
}
/*===========================================================================*
* ctty_io *
*===========================================================================*/
PUBLIC int ctty_io(task_nr, mess_ptr)
int task_nr; /* not used - for compatibility with dmap_t */
message *mess_ptr; /* pointer to message for task */
{
/* This routine is only called for one device, namely /dev/tty. Its job
* is to change the message to use the controlling terminal, instead of the
* major/minor pair for /dev/tty itself.
*/
struct dmap *dp;
if (fp->fp_tty == 0) {
/* No controlling tty present anymore, return an I/O error. */
mess_ptr->REP_STATUS = EIO;
} else {
/* Substitute the controlling terminal device. */
dp = &dmap[(fp->fp_tty >> MAJOR) & BYTE];
mess_ptr->DEVICE = (fp->fp_tty >> MINOR) & BYTE;
if (dp->dmap_driver == NONE) {
printf("FS: ctty_io: no driver for dev\n");
return(EIO);
}
if(isokendpt(dp->dmap_driver, &dummyproc) != OK) {
printf("FS: ctty_io: old driver %d\n", dp->dmap_driver);
return(EIO);
}
(*dp->dmap_io)(dp->dmap_driver, mess_ptr);
}
return(OK);
}
/*===========================================================================*
* no_dev *
*===========================================================================*/
PUBLIC int no_dev(
int UNUSED(op), /* operation, DEV_OPEN or DEV_CLOSE */
dev_t UNUSED(dev), /* device to open or close */
int UNUSED(proc), /* process to open/close for */
int UNUSED(flags) /* mode bits and flags */
)
{
/* Called when opening a nonexistent device. */
return(ENODEV);
}
/*===========================================================================*
* no_dev_io *
*===========================================================================*/
PUBLIC int no_dev_io(int proc, message *m)
{
/* Called when doing i/o on a nonexistent device. */
printf("VFS: I/O on unmapped device number\n");
return(EIO);
}
/*===========================================================================*
* clone_opcl *
*===========================================================================*/
PUBLIC int clone_opcl(
int op, /* operation, DEV_OPEN or DEV_CLOSE */
dev_t dev, /* device to open or close */
int proc_e, /* process to open/close for */
int flags /* mode bits and flags */
)
{
/* Some devices need special processing upon open. Such a device is "cloned",
* i.e. on a succesful open it is replaced by a new device with a new unique
* minor device number. This new device number identifies a new object (such
* as a new network connection) that has been allocated within a task.
*/
struct dmap *dp;
int r, minor;
message dev_mess;
assert(!IS_BDEV_RQ(op));
/* Determine task dmap. */
dp = &dmap[(dev >> MAJOR) & BYTE];
minor = (dev >> MINOR) & BYTE;
dev_mess.m_type = op;
dev_mess.DEVICE = minor;
dev_mess.USER_ENDPT = proc_e;
dev_mess.COUNT = flags;
if (dp->dmap_driver == NONE) {
printf("VFS clone_opcl: no driver for dev %x\n", dev);
return(ENXIO);
}
if(isokendpt(dp->dmap_driver, &dummyproc) != OK) {
printf("VFS clone_opcl: bad driver endpoint for dev %x (%d)\n", dev,
dp->dmap_driver);
return(ENXIO);
}
/* Call the task. */
r = (*dp->dmap_io)(dp->dmap_driver, &dev_mess);
if (r != OK) return(r);
if (op == DEV_OPEN && dev_mess.REP_STATUS >= 0) {
if (dev_mess.REP_STATUS != minor) {
struct vnode *vp;
struct node_details res;
/* A new minor device number has been returned.
* Request PFS to create a temporary device file to hold it.
*/
/* Device number of the new device. */
dev = (dev & ~(BYTE << MINOR)) | (dev_mess.REP_STATUS << MINOR);
/* Issue request */
r = req_newnode(PFS_PROC_NR, fp->fp_effuid, fp->fp_effgid,
ALL_MODES | I_CHAR_SPECIAL, dev, &res);
if (r != OK) {
(void) clone_opcl(DEV_CLOSE, dev, proc_e, 0);
return r;
}
/* Drop old node and use the new values */
vp = fp->fp_filp[m_in.fd]->filp_vno;
put_vnode(vp);
if ((vp = get_free_vnode()) == NULL)
vp = fp->fp_filp[m_in.fd]->filp_vno;
vp->v_fs_e = res.fs_e;
vp->v_vmnt = NULL;
vp->v_dev = NO_DEV;
vp->v_fs_e = res.fs_e;
vp->v_inode_nr = res.inode_nr;
vp->v_mode = res.fmode;
vp->v_sdev = dev;
vp->v_fs_count = 1;
vp->v_ref_count = 1;
fp->fp_filp[m_in.fd]->filp_vno = vp;
}
dev_mess.REP_STATUS = OK;
}
return(dev_mess.REP_STATUS);
}
/*===========================================================================*
* bdev_up *
*===========================================================================*/
PUBLIC void bdev_up(int maj)
{
/* A new block device driver has been mapped in. This may affect both mounted
* file systems and open block-special files.
*/
int r, new_driver_e, found;
struct filp *fp;
struct vmnt *vmp;
struct vnode *vp;
new_driver_e = dmap[maj].dmap_driver;
/* Tell each affected mounted file system about the new endpoint. This code
* is currently useless, as driver endpoints do not change across restarts.
*/
for (vmp = &vmnt[0]; vmp < &vmnt[NR_MNTS]; ++vmp) {
if (major(vmp->m_dev) != maj) continue;
/* Send the new driver endpoint to the mounted file system. */
if (OK != req_newdriver(vmp->m_fs_e, vmp->m_dev, new_driver_e))
printf("VFSdev_up: error sending new driver endpoint."
" FS_e: %d req_nr: %d\n", vmp->m_fs_e, REQ_NEW_DRIVER);
}
/* For each block-special file that was previously opened on the affected
* device, we need to reopen it on the new driver.
*/
found = 0;
for (fp = filp; fp < &filp[NR_FILPS]; fp++) {
if(fp->filp_count < 1 || !(vp = fp->filp_vno)) continue;
if(major(vp->v_sdev) != maj) continue;
if(!S_ISBLK(vp->v_mode)) continue;
/* Reopen the device on the driver, once per filp. */
if ((r = bdev_open(vp->v_sdev, fp->filp_mode & O_ACCMODE)) != OK)
printf("VFS: mounted dev %d/%d re-open failed: %d.\n",
maj, minor(vp->v_sdev), r);
found = 1;
}
/* If any block-special file was open for this major at all, also inform the
* root file system about the new endpoint of the driver. We do this even if
* the block-special file is linked to another mounted file system, merely
* because it is more work to check for that case.
*/
if (found) {
if (OK != req_newdriver(ROOT_FS_E, makedev(maj, 0), new_driver_e))
printf("VFSdev_up: error sending new driver endpoint."
" FS_e: %d req_nr: %d\n", ROOT_FS_E, REQ_NEW_DRIVER);
}
}
/*===========================================================================*
* cdev_up *
*===========================================================================*/
PUBLIC void cdev_up(int maj)
{
/* A new character device driver has been mapped in.
*/
int needs_reopen, fd_nr;
struct filp *fp;
struct fproc *rfp;
struct vnode *vp;
/* Look for processes that are suspened in an OPEN call. Set SUSP_REOPEN
* to indicate that this process was suspended before the call to dev_up.
*/
for (rfp = &fproc[0]; rfp < &fproc[NR_PROCS]; rfp++) {
if(rfp->fp_pid == PID_FREE) continue;
if(rfp->fp_blocked_on != FP_BLOCKED_ON_DOPEN) continue;
printf("dev_up: found process in FP_BLOCKED_ON_DOPEN, fd %d\n",
rfp->fp_block_fd);
fd_nr = rfp->fp_block_fd;
fp = rfp->fp_filp[fd_nr];
vp = fp->filp_vno;
if (!vp) panic("restart_reopen: no vp");
if ((vp->v_mode & I_TYPE) != I_CHAR_SPECIAL) continue;
if (((vp->v_sdev >> MAJOR) & BYTE) != maj) continue;
rfp->fp_flags |= SUSP_REOPEN;
}
needs_reopen= FALSE;
for (fp = filp; fp < &filp[NR_FILPS]; fp++) {
if(fp->filp_count < 1 || !(vp = fp->filp_vno)) continue;
if(((vp->v_sdev >> MAJOR) & BYTE) != maj) continue;
if(!S_ISCHR(vp->v_mode)) continue;
fp->filp_state = FS_NEEDS_REOPEN;
needs_reopen = TRUE;
}
if (needs_reopen)
restart_reopen(maj);
}
/*===========================================================================*
* restart_reopen *
*===========================================================================*/
PRIVATE void restart_reopen(maj)
int maj;
{
int n, r, minor, fd_nr;
endpoint_t driver_e;
struct vnode *vp;
struct filp *fp;
struct fproc *rfp;
for (fp = filp; fp < &filp[NR_FILPS]; fp++) {
if (fp->filp_count < 1 || !(vp = fp->filp_vno)) continue;
if (fp->filp_state != FS_NEEDS_REOPEN) continue;
if (((vp->v_sdev >> MAJOR) & BYTE) != maj) continue;
if ((vp->v_mode & I_TYPE) != I_CHAR_SPECIAL) continue;
minor = ((vp->v_sdev >> MINOR) & BYTE);
if (!(fp->filp_flags & O_REOPEN)) {
/* File descriptor is to be closed when driver restarts. */
n = invalidate(fp);
if (n != fp->filp_count) {
printf("VFS: warning: invalidate/count "
"discrepancy (%d, %d)\n", n, fp->filp_count);
}
fp->filp_count = 0;
continue;
}
r = dev_reopen(vp->v_sdev, fp-filp, vp->v_mode & (R_BIT|W_BIT));
if (r == OK) return;
/* Device could not be reopened. Invalidate all filps on that device.*/
n = invalidate(fp);
if (n != fp->filp_count) {
printf("VFS: warning: invalidate/count "
"discrepancy (%d, %d)\n", n, fp->filp_count);
}
fp->filp_count = 0;
printf("VFS: file on dev %d/%d re-open failed: %d; "
"invalidated %d fd's.\n", maj, minor, r, n);
}
/* Nothing more to re-open. Restart suspended processes */
driver_e= dmap[maj].dmap_driver;
for (rfp = &fproc[0]; rfp < &fproc[NR_PROCS]; rfp++) {
if(rfp->fp_pid == PID_FREE) continue;
if(rfp->fp_blocked_on == FP_BLOCKED_ON_OTHER &&
rfp->fp_task == driver_e && (rfp->fp_flags & SUSP_REOPEN)) {
rfp->fp_flags &= ~SUSP_REOPEN;
rfp->fp_blocked_on = FP_BLOCKED_ON_NONE;
reply(rfp->fp_endpoint, ERESTART);
}
}
/* Look for processes that are suspened in an OPEN call */
for (rfp = &fproc[0]; rfp < &fproc[NR_PROCS]; rfp++) {
if (rfp->fp_pid == PID_FREE) continue;
if (rfp->fp_blocked_on == FP_BLOCKED_ON_DOPEN ||
!(rfp->fp_flags & SUSP_REOPEN)) continue;
printf("restart_reopen: found process in FP_BLOCKED_ON_DOPEN, fd %d\n",
rfp->fp_block_fd);
fd_nr = rfp->fp_block_fd;
fp = rfp->fp_filp[fd_nr];
if (!fp) {
/* Open failed, and automatic reopen was not requested */
rfp->fp_blocked_on = FP_BLOCKED_ON_NONE;
FD_CLR(fd_nr, &rfp->fp_filp_inuse);
reply(rfp->fp_endpoint, EIO);
continue;
}
vp = fp->filp_vno;
if (!vp) panic("restart_reopen: no vp");
if ((vp->v_mode & I_TYPE) != I_CHAR_SPECIAL) continue;
if (((vp->v_sdev >> MAJOR) & BYTE) != maj) continue;
rfp->fp_blocked_on = FP_BLOCKED_ON_NONE;
reply(rfp->fp_endpoint, fd_nr);
}
}
/*===========================================================================*
* reopen_reply *
*===========================================================================*/
PUBLIC void reopen_reply()
{
endpoint_t driver_e;
int filp_no, status, maj;
struct filp *fp;
struct vnode *vp;
struct dmap *dp;
driver_e = m_in.m_source;
filp_no = m_in.REP_ENDPT;
status = m_in.REP_STATUS;
if (filp_no < 0 || filp_no >= NR_FILPS) {
printf("reopen_reply: bad filp number %d from driver %d\n", filp_no,
driver_e);
return;
}
fp = &filp[filp_no];
if (fp->filp_count < 1) {
printf("reopen_reply: filp number %d not inuse (from driver %d)\n",
filp_no, driver_e);
return;
}
vp = fp->filp_vno;
if (!vp) {
printf("reopen_reply: no vnode for filp number %d (from driver %d)\n",
filp_no, driver_e);
return;
}
if (fp->filp_state != FS_NEEDS_REOPEN) {
printf("reopen_reply: bad state %d for filp number %d"
" (from driver %d)\n", fp->filp_state, filp_no, driver_e);
return;
}
if ((vp->v_mode & I_TYPE) != I_CHAR_SPECIAL) {
printf("reopen_reply: bad mode 0%o for filp number %d"
" (from driver %d)\n", vp->v_mode, filp_no, driver_e);
return;
}
maj = ((vp->v_sdev >> MAJOR) & BYTE);
dp = &dmap[maj];
if (dp->dmap_driver != driver_e) {
printf("reopen_reply: bad major %d for filp number %d "
"(from driver %d, current driver is %d)\n", maj, filp_no,
driver_e, dp->dmap_driver);
return;
}
if (status == OK) {
fp->filp_state= FS_NORMAL;
} else {
printf("reopen_reply: should handle error status\n");
return;
}
restart_reopen(maj);
}
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