428 lines
13 KiB
C
428 lines
13 KiB
C
/* When a needed block is not in the cache, it must be fetched from the disk.
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* Special character files also require I/O. The routines for these are here.
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*
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* The entry points in this file are:
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* dev_open: FS opens a device
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* dev_close: FS closes a device
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* dev_io: FS does a read or write on a device
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* gen_opcl: generic call to a task to perform an open/close
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* gen_io: generic call to a task to perform an I/O operation
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* no_dev: open/close processing for devices that don't exist
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* tty_opcl: perform tty-specific processing for open/close
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* ctty_opcl: perform controlling-tty-specific processing for open/close
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* ctty_io: perform controlling-tty-specific processing for I/O
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* do_ioctl: perform the IOCTL system call
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* do_setsid: perform the SETSID system call (FS side)
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*/
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#include "fs.h"
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#include <fcntl.h>
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#include <minix/callnr.h>
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#include <minix/com.h>
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#include "dmap.h"
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#include "file.h"
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#include "fproc.h"
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#include "inode.h"
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#include "param.h"
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/*===========================================================================*
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* dev_open *
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*===========================================================================*/
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PUBLIC int dev_open(dev, proc, flags)
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dev_t dev; /* device to open */
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int proc; /* process to open for */
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int flags; /* mode bits and flags */
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{
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int major, r;
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struct dmap *dp;
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/* Determine the major device number call the device class specific
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* open/close routine. (This is the only routine that must check the
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* device number for being in range. All others can trust this check.)
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*/
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major = (dev >> MAJOR) & BYTE;
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if (major >= max_major) major = 0;
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dp = &dmap[major];
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r = (*dp->dmap_opcl)(DEV_OPEN, dev, proc, flags);
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if (r == SUSPEND) panic("Suspend on open from", dp->dmap_driver);
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return(r);
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}
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/*===========================================================================*
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* dev_close *
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*===========================================================================*/
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PUBLIC void dev_close(dev)
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dev_t dev; /* device to close */
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{
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(void) (*dmap[(dev >> MAJOR) & BYTE].dmap_opcl)(DEV_CLOSE, dev, 0, 0);
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}
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/*===========================================================================*
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* dev_io *
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*===========================================================================*/
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PUBLIC int dev_io(op, dev, proc, buf, pos, bytes, flags)
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int op; /* DEV_READ, DEV_WRITE, DEV_IOCTL, etc. */
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dev_t dev; /* major-minor device number */
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int proc; /* in whose address space is buf? */
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void *buf; /* virtual address of the buffer */
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off_t pos; /* byte position */
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int bytes; /* how many bytes to transfer */
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int flags; /* special flags, like O_NONBLOCK */
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{
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/* Read or write from a device. The parameter 'dev' tells which one. */
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struct dmap *dp;
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message dev_mess;
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/* Determine task dmap. */
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dp = &dmap[(dev >> MAJOR) & BYTE];
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/* Set up the message passed to task. */
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dev_mess.m_type = op;
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dev_mess.DEVICE = (dev >> MINOR) & BYTE;
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dev_mess.POSITION = pos;
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dev_mess.PROC_NR = proc;
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dev_mess.ADDRESS = buf;
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dev_mess.COUNT = bytes;
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dev_mess.TTY_FLAGS = flags;
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/* Call the task. */
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(*dp->dmap_io)(dp->dmap_driver, &dev_mess);
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/* Task has completed. See if call completed. */
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if (dev_mess.REP_STATUS == SUSPEND) {
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if (flags & O_NONBLOCK) {
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/* Not supposed to block. */
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dev_mess.m_type = CANCEL;
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dev_mess.PROC_NR = proc;
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dev_mess.DEVICE = (dev >> MINOR) & BYTE;
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(*dp->dmap_io)(dp->dmap_driver, &dev_mess);
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if (dev_mess.REP_STATUS == EINTR) dev_mess.REP_STATUS = EAGAIN;
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} else {
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/* Suspend user. */
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suspend(dp->dmap_driver);
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return(SUSPEND);
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}
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}
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return(dev_mess.REP_STATUS);
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}
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/*===========================================================================*
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* gen_opcl *
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*===========================================================================*/
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PUBLIC int gen_opcl(op, dev, proc, flags)
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int op; /* operation, DEV_OPEN or DEV_CLOSE */
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dev_t dev; /* device to open or close */
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int proc; /* process to open/close for */
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int flags; /* mode bits and flags */
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{
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/* Called from the dmap struct in table.c on opens & closes of special files.*/
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struct dmap *dp;
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message dev_mess;
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/* Determine task dmap. */
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dp = &dmap[(dev >> MAJOR) & BYTE];
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dev_mess.m_type = op;
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dev_mess.DEVICE = (dev >> MINOR) & BYTE;
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dev_mess.PROC_NR = proc;
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dev_mess.COUNT = flags;
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/* Call the task. */
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(*dp->dmap_io)(dp->dmap_driver, &dev_mess);
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return(dev_mess.REP_STATUS);
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}
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/*===========================================================================*
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* tty_opcl *
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*===========================================================================*/
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PUBLIC int tty_opcl(op, dev, proc, flags)
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int op; /* operation, DEV_OPEN or DEV_CLOSE */
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dev_t dev; /* device to open or close */
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int proc; /* process to open/close for */
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int flags; /* mode bits and flags */
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{
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/* This procedure is called from the dmap struct on tty open/close. */
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int r;
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register struct fproc *rfp;
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/* Add O_NOCTTY to the flags if this process is not a session leader, or
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* if it already has a controlling tty, or if it is someone elses
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* controlling tty.
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*/
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if (!fp->fp_sesldr || fp->fp_tty != 0) {
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flags |= O_NOCTTY;
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} else {
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for (rfp = &fproc[0]; rfp < &fproc[NR_PROCS]; rfp++) {
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if (rfp->fp_tty == dev) flags |= O_NOCTTY;
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}
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}
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r = gen_opcl(op, dev, proc, flags);
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/* Did this call make the tty the controlling tty? */
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if (r == 1) {
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fp->fp_tty = dev;
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r = OK;
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}
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return(r);
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}
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/*===========================================================================*
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* ctty_opcl *
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*===========================================================================*/
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PUBLIC int ctty_opcl(op, dev, proc, flags)
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int op; /* operation, DEV_OPEN or DEV_CLOSE */
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dev_t dev; /* device to open or close */
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int proc; /* process to open/close for */
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int flags; /* mode bits and flags */
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{
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/* This procedure is called from the dmap struct in table.c on opening/closing
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* /dev/tty, the magic device that translates to the controlling tty.
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*/
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return(fp->fp_tty == 0 ? ENXIO : OK);
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}
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/*===========================================================================*
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* do_setsid *
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*===========================================================================*/
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PUBLIC int do_setsid()
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{
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/* Perform the FS side of the SETSID call, i.e. get rid of the controlling
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* terminal of a process, and make the process a session leader.
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*/
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register struct fproc *rfp;
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/* Only MM may do the SETSID call directly. */
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if (who != PM_PROC_NR) return(ENOSYS);
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/* Make the process a session leader with no controlling tty. */
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rfp = &fproc[m_in.slot1];
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rfp->fp_sesldr = TRUE;
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rfp->fp_tty = 0;
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}
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/*===========================================================================*
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* do_ioctl *
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*===========================================================================*/
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PUBLIC int do_ioctl()
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{
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/* Perform the ioctl(ls_fd, request, argx) system call (uses m2 fmt). */
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struct filp *f;
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register struct inode *rip;
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dev_t dev;
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if ( (f = get_filp(m_in.ls_fd)) == NIL_FILP) return(err_code);
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rip = f->filp_ino; /* get inode pointer */
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if ( (rip->i_mode & I_TYPE) != I_CHAR_SPECIAL
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&& (rip->i_mode & I_TYPE) != I_BLOCK_SPECIAL) return(ENOTTY);
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dev = (dev_t) rip->i_zone[0];
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#if ENABLE_BINCOMPAT
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if ((m_in.TTY_REQUEST >> 8) == 't') {
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/* Obsolete sgtty ioctl, message contains more than is sane. */
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struct dmap *dp;
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message dev_mess;
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dp = &dmap[(dev >> MAJOR) & BYTE];
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dev_mess = m; /* Copy full message with all the weird bits. */
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dev_mess.m_type = DEV_IOCTL;
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dev_mess.PROC_NR = who;
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dev_mess.TTY_LINE = (dev >> MINOR) & BYTE;
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/* Call the task. */
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(*dp->dmap_io)(dp->dmap_driver, &dev_mess);
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m_out.TTY_SPEK = dev_mess.TTY_SPEK; /* erase and kill */
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m_out.TTY_FLAGS = dev_mess.TTY_FLAGS; /* flags */
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return(dev_mess.REP_STATUS);
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}
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#endif
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return(dev_io(DEV_IOCTL, dev, who, m_in.ADDRESS, 0L,
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m_in.REQUEST, f->filp_flags));
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}
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/*===========================================================================*
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* gen_io *
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*===========================================================================*/
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PUBLIC void gen_io(task_nr, mess_ptr)
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int task_nr; /* which task to call */
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message *mess_ptr; /* pointer to message for task */
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{
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/* All file system I/O ultimately comes down to I/O on major/minor device
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* pairs. These lead to calls on the following routines via the dmap table.
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*/
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int r, proc_nr;
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message local_m;
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proc_nr = mess_ptr->PROC_NR;
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if (! isokprocnr(proc_nr)) {
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printf("FS: warning, got illegal process number from %d.\n",
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mess_ptr->PROC_NR);
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return;
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}
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while ((r = sendrec(task_nr, mess_ptr)) == ELOCKED) {
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/* sendrec() failed to avoid deadlock. The task 'task_nr' is
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* trying to send a REVIVE message for an earlier request.
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* Handle it and go try again.
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*/
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if ((r = receive(task_nr, &local_m)) != OK) break;
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/* If we're trying to send a cancel message to a task which has just
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* sent a completion reply, ignore the reply and abort the cancel
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* request. The caller will do the revive for the process.
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*/
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if (mess_ptr->m_type == CANCEL && local_m.REP_PROC_NR == proc_nr)
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return;
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/* Otherwise it should be a REVIVE. */
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if (local_m.m_type != REVIVE) {
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printf(
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"fs: strange device reply from %d, type = %d, proc = %d\n",
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local_m.m_source,
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local_m.m_type, local_m.REP_PROC_NR);
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continue;
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}
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revive(local_m.REP_PROC_NR, local_m.REP_STATUS);
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}
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/* The message received may be a reply to this call, or a REVIVE for some
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* other process.
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*/
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for (;;) {
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if (r != OK) {
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if (r == EDEADDST) return; /* give up */
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else panic("call_task: can't send/receive", r);
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}
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/* Did the process we did the sendrec() for get a result? */
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if (mess_ptr->REP_PROC_NR == proc_nr) break;
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/* Otherwise it should be a REVIVE. */
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if (mess_ptr->m_type != REVIVE) {
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printf(
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"fs: strange device reply from %d, type = %d, proc = %d\n",
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mess_ptr->m_source,
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mess_ptr->m_type, mess_ptr->REP_PROC_NR);
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continue;
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}
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revive(mess_ptr->REP_PROC_NR, mess_ptr->REP_STATUS);
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r = receive(task_nr, mess_ptr);
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}
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}
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/*===========================================================================*
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* ctty_io *
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*===========================================================================*/
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PUBLIC void ctty_io(task_nr, mess_ptr)
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int task_nr; /* not used - for compatibility with dmap_t */
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message *mess_ptr; /* pointer to message for task */
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{
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/* This routine is only called for one device, namely /dev/tty. Its job
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* is to change the message to use the controlling terminal, instead of the
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* major/minor pair for /dev/tty itself.
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*/
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struct dmap *dp;
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if (fp->fp_tty == 0) {
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/* No controlling tty present anymore, return an I/O error. */
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mess_ptr->REP_STATUS = EIO;
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} else {
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/* Substitute the controlling terminal device. */
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dp = &dmap[(fp->fp_tty >> MAJOR) & BYTE];
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mess_ptr->DEVICE = (fp->fp_tty >> MINOR) & BYTE;
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(*dp->dmap_io)(dp->dmap_driver, mess_ptr);
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}
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}
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/*===========================================================================*
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* no_dev *
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*===========================================================================*/
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PUBLIC int no_dev(op, dev, proc, flags)
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int op; /* operation, DEV_OPEN or DEV_CLOSE */
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dev_t dev; /* device to open or close */
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int proc; /* process to open/close for */
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int flags; /* mode bits and flags */
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{
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/* Called when opening a nonexistent device. */
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return(ENODEV);
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}
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/*===========================================================================*
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* clone_opcl *
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*===========================================================================*/
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PUBLIC int clone_opcl(op, dev, proc, flags)
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int op; /* operation, DEV_OPEN or DEV_CLOSE */
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dev_t dev; /* device to open or close */
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int proc; /* process to open/close for */
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int flags; /* mode bits and flags */
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{
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/* Some devices need special processing upon open. Such a device is "cloned",
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* i.e. on a succesful open it is replaced by a new device with a new unique
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* minor device number. This new device number identifies a new object (such
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* as a new network connection) that has been allocated within a task.
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*/
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struct dmap *dp;
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int minor;
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message dev_mess;
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/* Determine task dmap. */
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dp = &dmap[(dev >> MAJOR) & BYTE];
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minor = (dev >> MINOR) & BYTE;
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dev_mess.m_type = op;
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dev_mess.DEVICE = minor;
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dev_mess.PROC_NR = proc;
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dev_mess.COUNT = flags;
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/* Call the task. */
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(*dp->dmap_io)(dp->dmap_driver, &dev_mess);
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if (op == DEV_OPEN && dev_mess.REP_STATUS >= 0) {
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if (dev_mess.REP_STATUS != minor) {
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/* A new minor device number has been returned. Create a
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* temporary device file to hold it.
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*/
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struct inode *ip;
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/* Device number of the new device. */
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dev = (dev & ~(BYTE << MINOR)) | (dev_mess.REP_STATUS << MINOR);
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ip = alloc_inode(root_dev, ALL_MODES | I_CHAR_SPECIAL);
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if (ip == NIL_INODE) {
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/* Oops, that didn't work. Undo open. */
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(void) clone_opcl(DEV_CLOSE, dev, proc, 0);
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return(err_code);
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}
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ip->i_zone[0] = dev;
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put_inode(fp->fp_filp[m_in.fd]->filp_ino);
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fp->fp_filp[m_in.fd]->filp_ino = ip;
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}
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dev_mess.REP_STATUS = OK;
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}
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return(dev_mess.REP_STATUS);
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}
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