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minix/servers/vfs/device.c
David van Moolenbroek 87337273e4 Remove support for reopening character devices 
Previously, VFS would reopen a character device after a driver crash
if the associated file descriptor was opened with the O_REOPEN flag.
This patch removes support for this feature. The code was complex,
full of uncovered corner cases, and hard to test. Moreover, it did not
actually hide the crash from user applications: they would get an
error code to indicate that something went wrong, and have to decide
based on the nature of the underlying device how to continue.

- remove support for O_REOPEN, and make playwave(1) reopen its device;
- remove support for the DEV_REOPEN protocol message;
- remove all code in VFS related to reopening character devices;
- no longer change VFS filp reference count and FD bitmap upon filp
  invalidation; instead, make get_filp* fail all calls on invalidated
  FDs except when obtained with the locktype VNODE_OPCL which is used
  by close_fd only;
- remove the VFS fproc file descriptor bitmap entirely, returning to
  the situation that a FD is in use if its slot points to a filp; use
  FILP_CLOSED as single means of marking a filp as invalidated.

Change-Id: I34f6bc69a036b3a8fc667c1f80435ff3af56558f
2014-03-01 09:04:52 +01:00

1003 lines
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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_close: close a character device
* cdev_reply: process the result of a character driver request
* bdev_open: open a block device
* bdev_close: close a block device
* bdev_reply: process the result of a block driver request
* dev_io: FS does a read or write on a device
* gen_opcl: generic call to a character driver to perform an open/close
* gen_io: generic call to a character driver to initiate I/O
* 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
* pm_setsid: perform VFS's side of setsid system call
* do_ioctl: perform the IOCTL system call
* dev_select: initiate a select call on a device
* dev_cancel: cancel an I/O request, blocking until it has been cancelled
*/
#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 "scratchpad.h"
#include "dmap.h"
#include <minix/vfsif.h>
#include "vnode.h"
#include "vmnt.h"
#include "param.h"
static int block_io(endpoint_t driver_e, message *mess_ptr);
static cp_grant_id_t make_grant(endpoint_t driver_e, endpoint_t user_e, int op,
void *buf, unsigned long size);
static int dummyproc;
/*===========================================================================*
* dev_open *
*===========================================================================*/
int dev_open(
dev_t dev, /* device to open */
int flags /* mode bits and flags */
)
{
/* Open a character device. */
devmajor_t major_dev;
int r;
/* 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(dev);
if (major_dev < 0 || major_dev >= NR_DEVICES) return(ENXIO);
if (dmap[major_dev].dmap_driver == NONE) return(ENXIO);
r = (*dmap[major_dev].dmap_opcl)(DEV_OPEN, dev, fp->fp_endpoint, flags);
return(r);
}
/*===========================================================================*
* dev_close *
*===========================================================================*/
int dev_close(
dev_t dev /* device to close */
)
{
/* Close a character device. */
devmajor_t major_dev;
int r;
/* See if driver is roughly valid. */
major_dev = major(dev);
if (major_dev < 0 || major_dev >= NR_DEVICES) return(ENXIO);
if (dmap[major_dev].dmap_driver == NONE) return(ENXIO);
r = (*dmap[major_dev].dmap_opcl)(DEV_CLOSE, dev, fp->fp_endpoint, 0);
return(r);
}
/*===========================================================================*
* bdev_open *
*===========================================================================*/
int bdev_open(dev_t dev, int access)
{
/* Open a block device. */
devmajor_t major_dev;
devminor_t minor_dev;
message dev_mess;
int r;
major_dev = major(dev);
minor_dev = minor(dev);
if (major_dev < 0 || major_dev >= NR_DEVICES) return ENXIO;
if (dmap[major_dev].dmap_driver == NONE) return ENXIO;
memset(&dev_mess, 0, sizeof(dev_mess));
dev_mess.m_type = BDEV_OPEN;
dev_mess.BDEV_MINOR = minor_dev;
dev_mess.BDEV_ACCESS = 0;
if (access & R_BIT) dev_mess.BDEV_ACCESS |= BDEV_R_BIT;
if (access & W_BIT) dev_mess.BDEV_ACCESS |= BDEV_W_BIT;
dev_mess.BDEV_ID = 0;
/* Call the task. */
r = block_io(dmap[major_dev].dmap_driver, &dev_mess);
if (r != OK)
return r;
return dev_mess.BDEV_STATUS;
}
/*===========================================================================*
* bdev_close *
*===========================================================================*/
int bdev_close(dev_t dev)
{
/* Close a block device. */
devmajor_t major_dev;
devminor_t minor_dev;
message dev_mess;
int r;
major_dev = major(dev);
minor_dev = minor(dev);
if (major_dev < 0 || major_dev >= NR_DEVICES) return ENXIO;
if (dmap[major_dev].dmap_driver == NONE) return ENXIO;
memset(&dev_mess, 0, sizeof(dev_mess));
dev_mess.m_type = BDEV_CLOSE;
dev_mess.BDEV_MINOR = minor_dev;
dev_mess.BDEV_ID = 0;
r = block_io(dmap[major_dev].dmap_driver, &dev_mess);
if (r != OK)
return r;
return dev_mess.BDEV_STATUS;
}
/*===========================================================================*
* bdev_ioctl *
*===========================================================================*/
static int bdev_ioctl(dev_t dev, endpoint_t proc_e, unsigned long req,
void *buf)
{
/* Perform an I/O control operation on a block device. */
struct dmap *dp;
cp_grant_id_t gid;
message dev_mess;
devmajor_t major_dev;
devminor_t minor_dev;
major_dev = major(dev);
minor_dev = minor(dev);
/* Determine task dmap. */
dp = &dmap[major_dev];
if (dp->dmap_driver == NONE) {
printf("VFS: bdev_ioctl: no driver for major %d\n", major_dev);
return(ENXIO);
}
/* Set up a grant if necessary. */
gid = make_grant(dp->dmap_driver, proc_e, BDEV_IOCTL, buf, req);
/* 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_USER = proc_e;
dev_mess.BDEV_ID = 0;
/* Call the task. */
block_io(dp->dmap_driver, &dev_mess);
/* Clean up. */
if (GRANT_VALID(gid)) cpf_revoke(gid);
if (dp->dmap_driver == NONE) {
printf("VFS: block driver gone!?\n");
return(EIO);
}
/* Return the result. */
return(dev_mess.BDEV_STATUS);
}
/*===========================================================================*
* find_suspended_ep *
*===========================================================================*/
static endpoint_t find_suspended_ep(endpoint_t driver, cp_grant_id_t g)
{
/* A process is suspended on a driver for which VFS 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_task == driver && rfp->fp_grant == g) {
assert(!fp_is_blocked(rfp) ||
rfp->fp_blocked_on == FP_BLOCKED_ON_OTHER);
return(rfp->fp_endpoint);
}
}
return(NONE);
}
/*===========================================================================*
* make_grant *
*===========================================================================*/
static cp_grant_id_t make_grant(endpoint_t driver_e, endpoint_t user_e, int op,
void *buf, unsigned long bytes)
{
/* Create a magic grant for the given operation and buffer. */
cp_grant_id_t gid;
int access;
size_t size;
switch (op) {
case DEV_READ_S:
case DEV_WRITE_S:
gid = cpf_grant_magic(driver_e, user_e, (vir_bytes) buf,
(size_t) bytes, op == DEV_READ_S ? CPF_WRITE : CPF_READ);
break;
case DEV_IOCTL_S:
case BDEV_IOCTL:
/* For IOCTLs, the bytes parameter contains the IOCTL request.
* This request encodes the requested access method and buffer size.
*/
access = 0;
if(_MINIX_IOCTL_IOR(bytes)) access |= CPF_WRITE;
if(_MINIX_IOCTL_IOW(bytes)) access |= CPF_READ;
if(_MINIX_IOCTL_BIG(bytes))
size = _MINIX_IOCTL_SIZE_BIG(bytes);
else
size = _MINIX_IOCTL_SIZE(bytes);
/* Grant access to the buffer even if no I/O happens with the ioctl, in
* order to disambiguate requests with DEV_IOCTL_S.
*/
gid = cpf_grant_magic(driver_e, user_e, (vir_bytes) buf, size, access);
break;
default:
panic("VFS: unknown operation %d", op);
}
if (!GRANT_VALID(gid))
panic("VFS: cpf_grant_magic failed");
return gid;
}
/*===========================================================================*
* dev_io *
*===========================================================================*/
int dev_io(
int op, /* DEV_READ_S, DEV_WRITE_S, or DEV_IOCTL_S */
dev_t dev, /* major-minor device number */
endpoint_t proc_e, /* in whose address space is buf? */
void *buf, /* virtual address of the buffer */
off_t pos, /* byte position */
size_t bytes, /* how many bytes to transfer */
int flags /* special flags, like O_NONBLOCK */
)
{
/* Initiate a read, write, or ioctl to a device. */
struct dmap *dp;
message dev_mess;
cp_grant_id_t gid;
devmajor_t major_dev;
devminor_t minor_dev;
int r;
assert(op == DEV_READ_S || op == DEV_WRITE_S || op == DEV_IOCTL_S);
/* Determine task dmap. */
major_dev = major(dev);
minor_dev = minor(dev);
dp = &dmap[major_dev];
/* See if driver is roughly valid. */
if (dp->dmap_driver == NONE) return(ENXIO);
if(isokendpt(dp->dmap_driver, &dummyproc) != OK) {
printf("VFS: dev_io: old driver for major %x (%d)\n", major_dev,
dp->dmap_driver);
return(ENXIO);
}
/* Create a grant for the buffer provided by the user process. */
gid = make_grant(dp->dmap_driver, proc_e, op, buf, bytes);
/* Set up the rest of the message that will be sent to the driver. */
memset(&dev_mess, 0, sizeof(dev_mess));
dev_mess.m_type = op;
dev_mess.DEVICE = minor_dev;
if (op == DEV_IOCTL_S) {
dev_mess.REQUEST = bytes;
dev_mess.POSITION = proc_e;
} else {
dev_mess.POSITION = ex64lo(pos);
dev_mess.COUNT = bytes;
}
dev_mess.HIGHPOS = ex64hi(pos);
dev_mess.USER_ENDPT = VFS_PROC_NR;
dev_mess.IO_GRANT = (void *) gid;
dev_mess.FLAGS = 0;
if (flags & O_NONBLOCK)
dev_mess.FLAGS |= FLG_OP_NONBLOCK;
/* Send the request to the driver. */
r = (*dp->dmap_io)(dp->dmap_driver, &dev_mess);
if (r != OK) {
cpf_revoke(gid);
return r;
}
/* Suspend the calling process until a reply arrives. */
wait_for(dp->dmap_driver);
assert(!GRANT_VALID(fp->fp_grant));
fp->fp_grant = gid; /* revoke this when unsuspended. */
fp->fp_ioproc = VFS_PROC_NR;
return SUSPEND;
}
/*===========================================================================*
* clone_cdev *
*===========================================================================*/
static int cdev_clone(dev_t dev, endpoint_t proc_e, devminor_t new_minor)
{
/* A new minor device number has been returned. Request PFS to create a
* temporary device file to hold it.
*/
struct vnode *vp;
struct node_details res;
int r;
assert(proc_e == fp->fp_endpoint);
/* Device number of the new device. */
dev = makedev(major(dev), new_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) gen_opcl(DEV_CLOSE, dev, proc_e, 0);
return r;
}
/* Drop old node and use the new values */
if ((vp = get_free_vnode()) == NULL) {
req_putnode(PFS_PROC_NR, res.inode_nr, 1); /* is this right? */
(void) gen_opcl(DEV_CLOSE, dev, proc_e, 0);
return(err_code);
}
lock_vnode(vp, VNODE_OPCL);
assert(fp->fp_filp[scratch(fp).file.fd_nr] != NULL);
unlock_vnode(fp->fp_filp[scratch(fp).file.fd_nr]->filp_vno);
put_vnode(fp->fp_filp[scratch(fp).file.fd_nr]->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[scratch(fp).file.fd_nr]->filp_vno = vp;
return OK;
}
/*===========================================================================*
* gen_opcl *
*===========================================================================*/
int gen_opcl(
int op, /* operation, DEV_OPEN or DEV_CLOSE */
dev_t dev, /* device to open or close */
endpoint_t proc_e, /* process to open/close for */
int flags /* mode bits and flags */
)
{
/* Called from the dmap struct on opens & closes of special files.*/
devmajor_t major_dev;
devminor_t minor_dev;
struct dmap *dp;
message dev_mess;
int r;
/* Determine task dmap. */
major_dev = major(dev);
minor_dev = minor(dev);
assert(major_dev >= 0 && major_dev < NR_DEVICES);
dp = &dmap[major_dev];
assert(dp->dmap_driver != NONE);
assert(!IS_BDEV_RQ(op));
/* Prepare the request message. */
memset(&dev_mess, 0, sizeof(dev_mess));
dev_mess.m_type = op;
dev_mess.DEVICE = minor_dev;
dev_mess.USER_ENDPT = proc_e;
dev_mess.COUNT = flags;
/* Call the task. */
r = (*dp->dmap_io)(dp->dmap_driver, &dev_mess);
if (r != OK) return(r);
/* Block the thread waiting for a reply. */
fp->fp_task = dp->dmap_driver;
self->w_task = dp->dmap_driver;
self->w_drv_sendrec = &dev_mess;
worker_wait();
self->w_task = NONE;
self->w_drv_sendrec = NULL;
/* Return the result from the driver. */
return(dev_mess.REP_STATUS);
}
/*===========================================================================*
* tty_opcl *
*===========================================================================*/
int tty_opcl(
int op, /* operation, DEV_OPEN or DEV_CLOSE */
dev_t dev, /* device to open or close */
endpoint_t 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_flags & 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 *
*===========================================================================*/
int ctty_opcl(
int op, /* operation, DEV_OPEN or DEV_CLOSE */
dev_t UNUSED(dev), /* device to open or close */
endpoint_t UNUSED(proc_e), /* process to open/close for */
int UNUSED(flags) /* mode bits and flags */
)
{
/* This procedure is called from the dmap struct on opening or closing
* /dev/tty, the magic device that translates to the controlling tty.
*/
if (IS_BDEV_RQ(op))
panic("ctty_opcl() called for block device request?");
return(fp->fp_tty == 0 ? ENXIO : OK);
}
/*===========================================================================*
* pm_setsid *
*===========================================================================*/
void pm_setsid(endpoint_t proc_e)
{
/* Perform the VFS 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_flags |= FP_SESLDR;
rfp->fp_tty = 0;
}
/*===========================================================================*
* do_ioctl *
*===========================================================================*/
int do_ioctl(message *UNUSED(m_out))
{
/* Perform the ioctl(ls_fd, request, argx) system call */
unsigned long ioctlrequest;
int r = OK;
struct filp *f;
register struct vnode *vp;
dev_t dev;
void *argx;
scratch(fp).file.fd_nr = job_m_in.VFS_IOCTL_FD;
ioctlrequest = job_m_in.VFS_IOCTL_REQ;
argx = job_m_in.VFS_IOCTL_ARG;
if ((f = get_filp(scratch(fp).file.fd_nr, VNODE_READ)) == NULL)
return(err_code);
vp = f->filp_vno; /* get vnode pointer */
if (!S_ISCHR(vp->v_mode) && !S_ISBLK(vp->v_mode)) {
r = ENOTTY;
}
if (r == OK) {
dev = (dev_t) vp->v_sdev;
if (S_ISBLK(vp->v_mode))
r = bdev_ioctl(dev, who_e, ioctlrequest, argx);
else
r = dev_io(DEV_IOCTL_S, dev, who_e, argx, 0,
ioctlrequest, f->filp_flags);
}
unlock_filp(f);
return(r);
}
/*===========================================================================*
* dev_select *
*===========================================================================*/
int dev_select(dev_t dev, int ops)
{
/* Initiate a select call on a device. Return OK iff the request was sent. */
devmajor_t major_dev;
devminor_t minor_dev;
message dev_mess;
struct dmap *dp;
major_dev = major(dev);
minor_dev = minor(dev);
dp = &dmap[major_dev];
if (dp->dmap_driver == NONE) return ENXIO;
memset(&dev_mess, 0, sizeof(dev_mess));
dev_mess.m_type = DEV_SELECT;
dev_mess.DEV_MINOR = minor_dev;
dev_mess.DEV_SEL_OPS = ops;
/* Call the task. */
return (*dp->dmap_io)(dp->dmap_driver, &dev_mess);
}
/*===========================================================================*
* dev_cancel *
*===========================================================================*/
int dev_cancel(dev_t dev)
{
/* Cancel an I/O request, blocking until it has been cancelled. */
devmajor_t major_dev;
devminor_t minor_dev;
message dev_mess;
struct dmap *dp;
int r;
major_dev = major(dev);
minor_dev = minor(dev);
dp = &dmap[major_dev];
memset(&dev_mess, 0, sizeof(dev_mess));
dev_mess.m_type = CANCEL;
dev_mess.DEVICE = minor_dev;
dev_mess.USER_ENDPT = fp->fp_ioproc;
dev_mess.IO_GRANT = (char *) fp->fp_grant;
/* Tell driver R or W. Mode is from current call, not open. */
/* FIXME: ioctls also pass through here! */
dev_mess.COUNT = fp->fp_block_callnr == READ ? R_BIT : W_BIT;
r = (*dp->dmap_io)(fp->fp_task, &dev_mess);
if (r != OK) return r; /* ctty_io returned an error? should be impossible */
/* Suspend this thread until we have received the response. */
fp->fp_task = dp->dmap_driver;
self->w_task = dp->dmap_driver;
self->w_drv_sendrec = &dev_mess;
worker_wait();
self->w_task = NONE;
self->w_drv_sendrec = NULL;
/* Clean up and return the result (note: the request may have completed). */
if (GRANT_VALID(fp->fp_grant)) {
(void) cpf_revoke(fp->fp_grant);
fp->fp_grant = GRANT_INVALID;
}
r = dev_mess.REP_STATUS;
return (r == EAGAIN) ? EINTR : r;
}
/*===========================================================================*
* block_io *
*===========================================================================*/
static int block_io(endpoint_t driver_e, message *mess_ptr)
{
/* Perform I/O on a block device. The current thread is suspended until a reply
* comes in from the driver.
*/
int r, status, retry_count;
message mess_retry;
assert(IS_BDEV_RQ(mess_ptr->m_type));
mess_retry = *mess_ptr;
retry_count = 0;
do {
r = drv_sendrec(driver_e, mess_ptr);
if (r == OK) {
status = mess_ptr->BDEV_STATUS;
if (status == ERESTART) {
r = EDEADEPT;
*mess_ptr = mess_retry;
retry_count++;
}
}
} while (status == ERESTART && retry_count < 5);
/* If we failed to restart the request, return EIO */
if (status == ERESTART && retry_count >= 5) {
r = OK;
mess_ptr->m_type = EIO;
}
if (r != OK) {
if (r == EDEADSRCDST || r == EDEADEPT) {
printf("VFS: dead driver %d\n", driver_e);
dmap_unmap_by_endpt(driver_e);
return(r);
} else if (r == ELOCKED) {
printf("VFS: ELOCKED talking to %d\n", driver_e);
return(r);
}
panic("block_io: can't send/receive: %d", r);
}
return(OK);
}
/*===========================================================================*
* gen_io *
*===========================================================================*/
int gen_io(endpoint_t drv_e, message *mess_ptr)
{
/* Initiate I/O to a character driver. Do not wait for the reply. */
int r;
assert(!IS_BDEV_RQ(mess_ptr->m_type));
r = asynsend3(drv_e, mess_ptr, AMF_NOREPLY);
if (r != OK) panic("VFS: asynsend in gen_io failed: %d", r);
/* Fake a SUSPEND */
mess_ptr->REP_STATUS = SUSPEND;
return(OK);
}
/*===========================================================================*
* ctty_io *
*===========================================================================*/
int ctty_io(
endpoint_t UNUSED(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. */
return(EIO);
} else {
/* Substitute the controlling terminal device. */
dp = &dmap[major(fp->fp_tty)];
mess_ptr->DEVICE = minor(fp->fp_tty);
if (dp->dmap_driver == NONE) {
printf("FS: ctty_io: no driver for dev\n");
return(EIO);
}
if (isokendpt(dp->dmap_driver, &dummyproc) != OK) {
printf("VFS: ctty_io: old driver %d\n", dp->dmap_driver);
return(EIO);
}
return (*dp->dmap_io)(dp->dmap_driver, mess_ptr);
}
}
/*===========================================================================*
* no_dev *
*===========================================================================*/
int no_dev(
int UNUSED(op), /* operation, DEV_OPEN or DEV_CLOSE */
dev_t UNUSED(dev), /* device to open or close */
endpoint_t 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 *
*===========================================================================*/
int no_dev_io(endpoint_t UNUSED(proc), message *UNUSED(m))
{
/* Called when doing i/o on a nonexistent device. */
printf("VFS: I/O on unmapped device number\n");
return(EIO);
}
/*===========================================================================*
* clone_opcl *
*===========================================================================*/
int clone_opcl(
int op, /* operation, DEV_OPEN or DEV_CLOSE */
dev_t dev, /* device to open or close */
endpoint_t 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.
*/
int r;
r = gen_opcl(op, dev, proc_e, flags);
if (op == DEV_OPEN && r >= 0) {
if (r != minor(dev))
r = cdev_clone(dev, proc_e, r);
else
r = OK;
}
return r;
}
/*===========================================================================*
* bdev_up *
*===========================================================================*/
void bdev_up(devmajor_t maj)
{
/* A new block device driver has been mapped in. This may affect both mounted
* file systems and open block-special files.
*/
int r, found, bits;
struct filp *rfilp;
struct vmnt *vmp;
struct vnode *vp;
char *label;
if (maj < 0 || maj >= NR_DEVICES) panic("VFS: out-of-bound major");
label = dmap[maj].dmap_label;
found = 0;
/* For each block-special file that was previously opened on the affected
* device, we need to reopen it on the new driver.
*/
for (rfilp = filp; rfilp < &filp[NR_FILPS]; rfilp++) {
if (rfilp->filp_count < 1 || !(vp = rfilp->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. */
bits = rfilp->filp_mode & (R_BIT|W_BIT);
if ((r = bdev_open(vp->v_sdev, bits)) != OK) {
printf("VFS: mounted dev %d/%d re-open failed: %d.\n",
maj, minor(vp->v_sdev), r);
dmap[maj].dmap_recovering = 0;
return; /* Give up entirely */
}
found = 1;
}
/* Tell each affected mounted file system about the new endpoint.
*/
for (vmp = &vmnt[0]; vmp < &vmnt[NR_MNTS]; ++vmp) {
if (major(vmp->m_dev) != maj) continue;
/* Send the driver label to the mounted file system. */
if (OK != req_newdriver(vmp->m_fs_e, vmp->m_dev, label))
printf("VFS dev_up: error sending new driver label to %d\n",
vmp->m_fs_e);
}
/* If any block-special file was open for this major at all, also inform the
* root file system about the new 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), label))
printf("VFSdev_up: error sending new driver label to %d\n",
ROOT_FS_E);
}
}
/*===========================================================================*
* opcl_reply *
*===========================================================================*/
static void opcl_reply(message *m_ptr)
{
/* A character driver has replied to an open or close request. This function
* MUST NOT block its calling thread.
*/
struct fproc *rfp;
struct worker_thread *wp;
endpoint_t proc_e;
int slot;
proc_e = m_ptr->REP_ENDPT;
if (isokendpt(proc_e, &slot) != OK) return;
rfp = &fproc[slot];
wp = rfp->fp_worker;
if (wp == NULL || wp->w_task != who_e) {
printf("VFS: no worker thread waiting for a reply from %d\n", who_e);
return;
}
*wp->w_drv_sendrec = *m_ptr;
worker_signal(wp); /* Continue open/close */
}
/*===========================================================================*
* task_reply *
*===========================================================================*/
static void task_reply(message *m_ptr)
{
/* A character driver has results for a read, write, or ioctl call. There may
* be a thread waiting for these results as part of an ongoing dev_cancel call.
* If so, wake up that thread; if not, send a reply to the requesting process.
* This function MUST NOT block its calling thread.
*/
struct fproc *rfp;
struct worker_thread *wp;
endpoint_t proc_e;
int slot;
proc_e = m_ptr->REP_ENDPT;
if (proc_e == VFS_PROC_NR)
proc_e = find_suspended_ep(m_ptr->m_source, m_ptr->REP_IO_GRANT);
else
printf("VFS: endpoint %u from %u is not VFS\n",
proc_e, m_ptr->m_source);
if (proc_e == NONE) {
printf("VFS: proc with grant %d from %d not found\n",
m_ptr->REP_IO_GRANT, m_ptr->m_source);
} else if (m_ptr->REP_STATUS == SUSPEND) {
printf("VFS: got SUSPEND on DEV_REVIVE: not reviving proc\n");
} else {
/* If there is a thread active for this process, we assume that this
* thread aims to cancel the ongoing operation. In that case, wake up
* the thread to let it finish unpausing the process. Otherwise, revive
* the process as usual.
*/
if (isokendpt(proc_e, &slot) != OK) return;
rfp = &fproc[slot];
wp = rfp->fp_worker;
if (wp != NULL && wp->w_task == who_e) {
assert(!fp_is_blocked(rfp));
*wp->w_drv_sendrec = *m_ptr;
worker_signal(wp); /* Continue cancel */
} else {
revive(proc_e, m_ptr->REP_STATUS);
}
}
}
/*===========================================================================*
* cdev_reply *
*===========================================================================*/
void cdev_reply(void)
{
/* A character driver has results for us. */
switch (call_nr) {
case DEV_OPEN_REPL:
case DEV_CLOSE_REPL: opcl_reply(&m_in); break;
case DEV_REVIVE: task_reply(&m_in); break;
case DEV_SEL_REPL1:
select_reply1(m_in.m_source, m_in.DEV_MINOR, m_in.DEV_SEL_OPS);
break;
case DEV_SEL_REPL2:
select_reply2(m_in.m_source, m_in.DEV_MINOR, m_in.DEV_SEL_OPS);
break;
default:
printf("VFS: char driver %u sent unknown reply %x\n", who_e, call_nr);
}
}
/*===========================================================================*
* bdev_reply *
*===========================================================================*/
void bdev_reply(struct dmap *dp)
{
/* A block driver has results for a call. There must be a thread waiting for
* these results - wake it up. This function MUST NOT block its calling thread.
*/
struct worker_thread *wp;
assert(dp != NULL);
assert(dp->dmap_servicing != NONE);
wp = worker_get(dp->dmap_servicing);
if (wp == NULL || wp->w_task != who_e) {
printf("VFS: no worker thread waiting for a reply from %d\n", who_e);
return;
}
assert(wp->w_drv_sendrec != NULL);
*wp->w_drv_sendrec = m_in;
wp->w_drv_sendrec = NULL;
worker_signal(wp);
}
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