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minix/servers/fs/device.c

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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: 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 <minix/callnr.h>
#include <minix/com.h>
#include <minix/endpoint.h>
#include "file.h"
#include "fproc.h"
#include "inode.h"
#include "param.h"
#include "super.h"
#define ELEMENTS(a) (sizeof(a)/sizeof((a)[0]))
extern int dmap_size;
PRIVATE int dummyproc;
/*===========================================================================*
* dev_open *
*===========================================================================*/
PUBLIC int dev_open(dev, proc, flags)
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);
if (r == SUSPEND) panic(__FILE__,"suspend on open from", dp->dmap_driver);
return(r);
}
/*===========================================================================*
* dev_close *
*===========================================================================*/
PUBLIC void dev_close(dev)
dev_t dev; /* device to close */
{
/* See if driver is roughly valid. */
if (dmap[(dev >> MAJOR)].dmap_driver == NONE) {
return;
}
(void) (*dmap[(dev >> MAJOR) & BYTE].dmap_opcl)(DEV_CLOSE, dev, 0, 0);
}
/*===========================================================================*
* dev_status *
*===========================================================================*/
PUBLIC void dev_status(message *m)
{
message st;
int d, get_more = 1;
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;
do {
int r;
st.m_type = DEV_STATUS;
if ((r=sendrec(m->m_source, &st)) != OK) {
printf("DEV_STATUS failed to %d: %d\n", m->m_source, r);
if (r == EDEADSRCDST) return;
if (r == EDSTDIED) return;
if (r == ESRCDIED) return;
panic(__FILE__,"couldn't sendrec for DEV_STATUS", r);
}
switch(st.m_type) {
case DEV_REVIVE:
revive(st.REP_ENDPT, st.REP_STATUS);
break;
case DEV_IO_READY:
select_notified(d, 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;
}
/*===========================================================================*
* dev_io *
*===========================================================================*/
PUBLIC int dev_io(op, dev, proc_e, buf, pos, bytes, flags)
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 */
off_t pos; /* byte position */
int bytes; /* how many bytes to transfer */
int flags; /* special flags, like O_NONBLOCK */
{
/* Read or write from a device. The parameter 'dev' tells which one. */
struct dmap *dp;
message dev_mess;
/* 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(isokendpt(dp->dmap_driver, &dummyproc) != OK) {
printf("FS: dev_io: old driver for dev %x (%d)\n",
dev, dp->dmap_driver);
return ENXIO;
}
/* Set up the message passed to task. */
dev_mess.m_type = op;
dev_mess.DEVICE = (dev >> MINOR) & BYTE;
dev_mess.POSITION = pos;
dev_mess.IO_ENDPT = proc_e;
dev_mess.ADDRESS = buf;
dev_mess.COUNT = bytes;
dev_mess.TTY_FLAGS = flags;
/* Call the task. */
(*dp->dmap_io)(dp->dmap_driver, &dev_mess);
if(dp->dmap_driver == NONE)
panic(__FILE__,"dev_io: driver changed to NONE", NO_NUM);
/* Task has completed. See if call completed. */
if (dev_mess.REP_STATUS == SUSPEND) {
if (flags & O_NONBLOCK) {
/* Not supposed to block. */
dev_mess.m_type = CANCEL;
dev_mess.IO_ENDPT = proc_e;
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 {
/* Suspend user. */
suspend(dp->dmap_driver);
return(SUSPEND);
}
}
return(dev_mess.REP_STATUS);
}
/*===========================================================================*
* gen_opcl *
*===========================================================================*/
PUBLIC int gen_opcl(op, dev, proc_e, flags)
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.*/
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.IO_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;
}
if(isokendpt(dp->dmap_driver, &dummyproc) != OK) {
printf("FS: gen_opcl: old driver for dev %x (%d)\n",
dev, dp->dmap_driver);
return ENXIO;
}
/* Call the task. */
(*dp->dmap_io)(dp->dmap_driver, &dev_mess);
return(dev_mess.REP_STATUS);
}
/*===========================================================================*
* tty_opcl *
*===========================================================================*/
PUBLIC int tty_opcl(op, dev, proc_e, flags)
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_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(op, dev, proc_e, flags)
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);
}
/*===========================================================================*
* do_setsid *
*===========================================================================*/
PUBLIC int do_setsid()
{
/* 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;
/* Only MM may do the SETSID call directly. */
if (who_e != PM_PROC_NR) return(ENOSYS);
/* Make the process a session leader with no controlling tty. */
okendpt(m_in.endpt1, &slot);
rfp = &fproc[slot];
rfp->fp_sesldr = TRUE;
rfp->fp_tty = 0;
return(OK);
}
/*===========================================================================*
* do_ioctl *
*===========================================================================*/
PUBLIC int do_ioctl()
{
/* Perform the ioctl(ls_fd, request, argx) system call (uses m2 fmt). */
struct filp *f;
register struct inode *rip;
dev_t dev;
if ( (f = get_filp(m_in.ls_fd)) == NIL_FILP) return(err_code);
rip = f->filp_ino; /* get inode pointer */
if ( (rip->i_mode & I_TYPE) != I_CHAR_SPECIAL
&& (rip->i_mode & I_TYPE) != I_BLOCK_SPECIAL) return(ENOTTY);
dev = (dev_t) rip->i_zone[0];
#if ENABLE_BINCOMPAT
if ((m_in.TTY_REQUEST >> 8) == 't') {
/* Obsolete sgtty ioctl, message contains more than is sane. */
struct dmap *dp;
message dev_mess;
dp = &dmap[(dev >> MAJOR) & BYTE];
dev_mess = m; /* Copy full message with all the weird bits. */
dev_mess.m_type = DEV_IOCTL;
dev_mess.PROC_NR = who_e;
dev_mess.TTY_LINE = (dev >> MINOR) & BYTE;
/* Call the task. */
if (dp->dmap_driver == NONE) {
printf("FS: do_ioctl: no driver for dev %x\n", dev);
return ENXIO;
}
if(isokendpt(dp->dmap_driver, &dummyproc) != OK) {
printf("FS: do_ioctl: old driver for dev %x (%d)\n",
dev, dp->dmap_driver);
return ENXIO;
}
(*dp->dmap_io)(dp->dmap_driver, &dev_mess);
m_out.TTY_SPEK = dev_mess.TTY_SPEK; /* erase and kill */
m_out.TTY_FLAGS = dev_mess.TTY_FLAGS; /* flags */
return(dev_mess.REP_STATUS);
}
#endif
return(dev_io(DEV_IOCTL, dev, who_e, m_in.ADDRESS, 0L,
m_in.REQUEST, f->filp_flags));
}
/*===========================================================================*
* 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, dummy_proc;
message local_m;
proc_e = mess_ptr->IO_ENDPT;
#if DEAD_CODE
while ((r = sendrec(task_nr, mess_ptr)) == ELOCKED) {
/* sendrec() failed to avoid deadlock. The task 'task_nr' is
* trying to send a REVIVE message for an earlier request.
* Handle it and go try again.
*/
if ((r = receive(task_nr, &local_m)) != OK) {
break;
}
/* If we're trying to send a cancel message to a task which has just
* sent a completion reply, ignore the reply and abort the cancel
* request. The caller will do the revive for the process.
*/
if (mess_ptr->m_type == CANCEL && local_m.REP_ENDPT == proc_e) {
return OK;
}
/* Otherwise it should be a REVIVE. */
if (local_m.m_type != REVIVE) {
printf(
"fs: strange device reply from %d, type = %d, proc = %d (1)\n",
local_m.m_source,
local_m.m_type, local_m.REP_ENDPT);
continue;
}
revive(local_m.REP_ENDPT, local_m.REP_STATUS);
}
#endif
/* The message received may be a reply to this call, or a REVIVE for some
* other process.
*/
r = sendrec(task_nr, mess_ptr);
for(;;) {
if (r != OK) {
if (r == EDEADSRCDST || r == EDSTDIED || r == ESRCDIED) {
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(__FILE__,"call_task: can't send/receive", r);
}
/* Did the process we did the sendrec() for get a result? */
if (mess_ptr->REP_ENDPT == proc_e) {
break;
} else if (mess_ptr->m_type == REVIVE) {
/* Otherwise it should be a REVIVE. */
revive(mess_ptr->REP_ENDPT, mess_ptr->REP_STATUS);
} else {
printf(
"fs: strange device reply from %d, type = %d, proc = %d (2) ignored\n",
mess_ptr->m_source,
mess_ptr->m_type, mess_ptr->REP_ENDPT);
}
r = receive(task_nr, mess_ptr);
}
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(op, dev, proc, flags)
int op; /* operation, DEV_OPEN or DEV_CLOSE */
dev_t dev; /* device to open or close */
int proc; /* process to open/close for */
int 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("FS: I/O on unmapped device number\n");
return EIO;
}
/*===========================================================================*
* clone_opcl *
*===========================================================================*/
PUBLIC int clone_opcl(op, dev, proc_e, flags)
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.IO_ENDPT = proc_e;
dev_mess.COUNT = flags;
if (dp->dmap_driver == NONE) {
printf("FS: clone_opcl: no driver for dev %x\n", dev);
return ENXIO;
}
if(isokendpt(dp->dmap_driver, &dummyproc) != OK) {
printf("FS: clone_opcl: old driver 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) {
/* A new minor device number has been returned. Create a
* temporary device file to hold it.
*/
struct inode *ip;
/* Device number of the new device. */
dev = (dev & ~(BYTE << MINOR)) | (dev_mess.REP_STATUS << MINOR);
ip = alloc_inode(root_dev, ALL_MODES | I_CHAR_SPECIAL);
if (ip == NIL_INODE) {
/* Oops, that didn't work. Undo open. */
(void) clone_opcl(DEV_CLOSE, dev, proc_e, 0);
return(err_code);
}
ip->i_zone[0] = dev;
put_inode(fp->fp_filp[m_in.fd]->filp_ino);
fp->fp_filp[m_in.fd]->filp_ino = ip;
}
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.
*/
struct super_block *sb;
struct filp *fp;
int r;
/* Open a device once for every filp that's opened on it,
* and once for every filesystem mounted from it.
*/
for(sb = super_block; sb < &super_block[NR_SUPERS]; sb++) {
int minor;
if(sb->s_dev == NO_DEV)
continue;
if(((sb->s_dev >> MAJOR) & BYTE) != maj)
continue;
minor = ((sb->s_dev >> MINOR) & BYTE);
printf("FS: remounting dev %d/%d\n", maj, minor);
if((r = dev_open(sb->s_dev, FS_PROC_NR,
sb->s_rd_only ? R_BIT : (R_BIT|W_BIT))) != OK) {
printf("FS: mounted dev %d/%d re-open failed: %d.\n",
maj, minor, r);
}
}
for(fp = filp; fp < &filp[NR_FILPS]; fp++) {
struct inode *in;
int minor;
if(fp->filp_count < 1 || !(in=fp->filp_ino)) continue;
if(((in->i_zone[0] >> MAJOR) & BYTE) != maj) continue;
if(!(in->i_mode & (I_BLOCK_SPECIAL|I_CHAR_SPECIAL))) continue;
minor = ((in->i_zone[0] >> MINOR) & BYTE);
printf("FS: reopening special %d/%d..\n", maj, minor);
if((r = dev_open(in->i_zone[0], FS_PROC_NR,
in->i_mode & (R_BIT|W_BIT))) != OK) {
int n;
/* This function will set the fp_filp[]s of processes
* holding that fp to NULL, but _not_ clear
* fp_filp_inuse, so that fd can't be recycled until
* it's close()d.
*/
n = inval_filp(fp);
if(n != fp->filp_count)
printf("FS: warning: invalidate/count "
"discrepancy (%d, %d)\n", n, fp->filp_count);
fp->filp_count = 0;
printf("FS: file on dev %d/%d re-open failed: %d; "
"invalidated %d fd's.\n", maj, minor, r, n);
}
}
return;
}
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