sanchayanmaity/minix
1
0
Fork 0
Code Issues Pull requests Packages Projects Releases Wiki Activity
minix/servers/vfs/device.c
Thomas Veerman aba392e630 Clean up and fix multiple bugs in select: 
- Remove redundant code.
 - Always wait for the initial reply from an asynchronous select request,
   even if the select has been satisfied on another file descriptor or
   was canceled due to a serious error.
 - Restart asynchronous selects if upon reply from the driver turns out
   that there are deferred operations (and do not forget we're still
   interested in the results of the deferred operations).
 - Do not hang a non-blocking select when another blocking select on
   the same filp is still blocking.
 - Split blocking operations in read, write, and exceptions (i.e.,
   blocking on read does not imply the write will block as well).
 - Some loops would iterate over OPEN_MAX file descriptors instead of
   the "highest" file descriptor.
 - Use proper internal error return values.
 - A secondary reply from a synchronous driver is essentially the same
   as from an asynchronous driver (the only difference being how the 
   answer is received). Merge.
 - Return proper error code after a driver failure.
 - Auto-detect whether a driver is synchronous or asynchronous.
 - Remove some code duplication.
 - Clean up code (coding style, add missing comments, put all select
   related code together).
2011-04-13 13:25:34 +00:00

1094 lines
32 KiB
C
Raw Blame History

/* 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: FS opens a device
* dev_close: FS closes a 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 <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 */
)
{
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_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 */
)
{
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
)
{
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);
}
/*===========================================================================*
* 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, 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 */
)
{
/* Called from the dmap struct in table.c on opens & closes of special files.*/
int r;
struct dmap *dp;
message dev_mess;
/* Determine task dmap. */
dp = &dmap[(dev >> MAJOR) & BYTE];
dev_mess.m_type = op;
dev_mess.DEVICE = (dev >> MINOR) & BYTE;
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);
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;
/* 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.
*/
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;
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, proc_e;
if(task_nr == SYSTEM) {
printf("VFS: sending %d to SYSTEM\n", mess_ptr->m_type);
}
proc_e = mess_ptr->USER_ENDPT;
for (;;) {
r = sendrec(task_nr, mess_ptr);
if(r == OK && mess_ptr->REP_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 (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) ||
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;
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;
/* 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);
}
/*===========================================================================*
* dev_up *
*===========================================================================*/
PUBLIC void dev_up(int maj)
{
/* A new device driver has been mapped in. This function
* checks if any filesystems are mounted on it, and if so,
* dev_open()s them so the filesystem can be reused.
*/
int r, new_driver_e, needs_reopen, fd_nr, found;
struct filp *fp;
struct vmnt *vmp;
struct fproc *rfp;
struct vnode *vp;
/* First deal with block devices. We need to consider both mounted file
* systems and open block-special files.
*/
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 = dev_open(vp->v_sdev, VFS_PROC_NR, fp->filp_mode)) != 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);
}
/* The rest of the code deals with character-special files. To start with,
* 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);
}
Reference in a new issue View git blame Copy permalink