+/* mx1.c 4.6 81/03/11 */
+
+#include "../h/param.h"
+#include "../h/systm.h"
+#include "../h/dir.h"
+#include "../h/user.h"
+#include "../h/reg.h"
+#include "../h/proc.h"
+#include "../h/tty.h"
+#include "../h/inode.h"
+#include "../h/mx.h"
+#include "../h/file.h"
+#include "../h/conf.h"
+
+/*
+ * Multiplexor: clist version
+ *
+ * installation:
+ * requires a line in cdevsw -
+ * mxopen, mxclose, mxread, mxwrite, mxioctl, 0,
+ *
+ * also requires a line in linesw -
+ * mxopen, mxclose, mcread, mcwrite, mxioctl, nulldev, nulldev,
+ *
+ * The linesw entry for mpx should be the last one in the table.
+ * 'nldisp' (number of line disciplines) should not include the
+ * mpx line. This is to prevent mpx from being enabled by an ioctl.
+ */
+struct chan chans[NCHANS];
+struct schan schans[NPORTS];
+struct group *groups[NGROUPS];
+int mpxline;
+struct chan *xcp();
+dev_t mpxdev = -1;
+
+
+char mcdebugs[NDEBUGS];
+
+
+/*
+ * Allocate a channel, set c_index to index.
+ */
+struct chan *
+challoc(index, isport)
+{
+register s,i;
+register struct chan *cp;
+
+ s = spl6();
+ for(i=0;i<((isport)?NPORTS:NCHANS);i++) {
+ cp = (isport)? (struct chan *)(schans+i): chans+i;
+ if(cp->c_group == NULL) {
+ cp->c_index = index;
+ cp->c_pgrp = 0;
+ cp->c_flags = 0;
+ splx(s);
+ return(cp);
+ }
+ }
+ splx(s);
+ return(NULL);
+}
+
+
+
+/*
+ * Allocate a group table cell.
+ */
+gpalloc()
+{
+ register i;
+
+ for (i=NGROUPS-1; i>=0; i--)
+ if (groups[i]==NULL) {
+ groups[i]++;
+ return(i);
+ }
+ u.u_error = ENXIO;
+ return(i);
+}
+
+
+/*
+ * Add a channel to the group in
+ * inode ip.
+ */
+struct chan *
+addch(ip, isport)
+struct inode *ip;
+{
+register struct chan *cp;
+register struct group *gp;
+register i;
+
+ plock(ip);
+ gp = &ip->i_un.i_group;
+ for(i=0;i<NINDEX;i++) {
+ cp = (struct chan *)gp->g_chans[i];
+ if (cp == NULL) {
+ if ((cp=challoc(i, isport)) != NULL) {
+ gp->g_chans[i] = cp;
+ cp->c_group = gp;
+ }
+ break;
+ }
+ cp = NULL;
+ }
+ prele(ip);
+ return(cp);
+}
+
+/*
+ * Mpxchan system call.
+ */
+
+mpxchan()
+{
+ extern mxopen(), mcread(), sdata(), scontrol();
+ struct inode *ip, *gip;
+ struct tty *tp;
+ struct file *fp, *chfp, *gfp;
+ struct chan *cp;
+ struct group *gp, *ngp;
+ struct mx_args vec;
+ struct a {
+ int cmd;
+ int *argvec;
+ } *uap;
+ dev_t dev;
+ register int i;
+
+ /*
+ * Common setup code.
+ */
+
+ uap = (struct a *)u.u_ap;
+ (void) copyin((caddr_t)uap->argvec, (caddr_t)&vec, sizeof vec);
+ gp = NULL; gfp = NULL; cp = NULL;
+
+ switch(uap->cmd) {
+
+ case NPGRP:
+ if (vec.m_arg[1] < 0)
+ break;
+ case CHAN:
+ case JOIN:
+ case EXTR:
+ case ATTACH:
+ case DETACH:
+ case CSIG:
+ gfp = getf(vec.m_arg[1]);
+ if (gfp==NULL)
+ return;
+ gip = gfp->f_inode;
+ gp = &gip->i_un.i_group;
+ if (gp->g_inode != gip) {
+ u.u_error = ENXIO;
+ return;
+ }
+ }
+
+ switch(uap->cmd) {
+
+ /*
+ * Create an MPX file.
+ */
+
+ case MPX:
+ case MPXN:
+ if (mpxdev < 0) {
+ for (i=0; linesw[i].l_open; i++) {
+ if (linesw[i].l_read==mcread) {
+ mpxline = i;
+ for (i=0; cdevsw[i].d_open; i++) {
+ if (cdevsw[i].d_open==mxopen) {
+ mpxdev = (dev_t)(i<<8);
+ }
+ }
+ }
+ }
+ if (mpxdev < 0) {
+ u.u_error = ENXIO;
+ return;
+ }
+ }
+ if (uap->cmd==MPXN) {
+ if ((ip=ialloc(pipedev))==NULL)
+ return;
+ ip->i_mode = ((vec.m_arg[1]&0777)+IFMPC) & ~u.u_cmask;
+ ip->i_flag = IACC|IUPD|ICHG;
+ } else {
+ u.u_dirp = vec.m_name;
+ ip = namei(uchar,1);
+ if (ip != NULL) {
+ i = ip->i_mode&IFMT;
+ u.u_error = EEXIST;
+ if (i==IFMPC || i==IFMPB) {
+ i = minor(ip->i_un.i_rdev);
+ gp = groups[i];
+ if (gp && gp->g_inode==ip)
+ u.u_error = EBUSY;
+ }
+ iput(ip);
+ return;
+ }
+ if (u.u_error)
+ return;
+ ip = maknode((vec.m_arg[1]&0777)+IFMPC);
+ if (ip == NULL)
+ return;
+ }
+ if ((i=gpalloc()) < 0) {
+ iput(ip);
+ return;
+ }
+ if ((fp=falloc()) == NULL) {
+ iput(ip);
+ groups[i] = NULL;
+ return;
+ }
+ ip->i_un.i_rdev = (daddr_t)(mpxdev+i);
+ ip->i_count++;
+ prele(ip);
+
+ gp = &ip->i_un.i_group;
+ groups[i] = gp;
+ gp->g_inode = ip;
+ gp->g_state = INUSE|ISGRP;
+ gp->g_group = NULL;
+ gp->g_file = fp;
+ gp->g_index = 0;
+ gp->g_rotmask = 1;
+ gp->g_rot = 0;
+ gp->g_datq = 0;
+ for(i=0;i<NINDEX;)
+ gp->g_chans[i++] = NULL;
+
+ fp->f_flag = FREAD|FWRITE|FMP;
+ fp->f_inode = ip;
+ fp->f_un.f_chan = NULL;
+ return;
+
+ /*
+ * join file descriptor (arg 0) to group (arg 1)
+ * return channel number
+ */
+
+ case JOIN:
+ if ((fp=getf(vec.m_arg[0]))==NULL)
+ return;
+ ip = fp->f_inode;
+ switch (ip->i_mode & IFMT) {
+
+ case IFMPC:
+ if ((fp->f_flag&FMP) != FMP) {
+ u.u_error = ENXIO;
+ return;
+ }
+ ngp = &ip->i_un.i_group;
+ if (mtree(ngp, gp) == NULL)
+ return;
+ fp->f_count++;
+ u.u_r.r_val1 = cpx((struct chan *)ngp);
+ return;
+
+ case IFCHR:
+ dev = (dev_t)ip->i_un.i_rdev;
+ tp = cdevsw[major(dev)].d_ttys;
+ if (tp==NULL) {
+ u.u_error = ENXIO;
+ return;
+ }
+ tp = &tp[minor(dev)];
+ if (tp->t_chan) {
+ u.u_error = ENXIO;
+ return;
+ }
+ if ((cp=addch(gip, 1))==NULL) {
+ u.u_error = ENXIO;
+ return;
+ }
+ tp->t_chan = cp;
+ cp->c_fy = fp;
+ fp->f_count++;
+ cp->c_ttyp = tp;
+ cp->c_line = tp->t_line;
+ cp->c_flags = XGRP+PORT;
+ u.u_r.r_val1 = cpx(cp);
+ return;
+
+ default:
+ u.u_error = ENXIO;
+ return;
+
+ }
+
+ /*
+ * Attach channel (arg 0) to group (arg 1).
+ */
+
+ case ATTACH:
+ cp = xcp(gp, vec.m_arg[0]);
+ if (cp==NULL || cp->c_flags&ISGRP) {
+ u.u_error = ENXIO;
+ return;
+ }
+ u.u_r.r_val1 = cpx(cp);
+ wakeup((caddr_t)cp);
+ return;
+
+ case DETACH:
+ cp = xcp(gp, vec.m_arg[0]);
+ if (cp==NULL) {
+ u.u_error = ENXIO;
+ return;
+ }
+ (void) detach(cp);
+ return;
+
+ /*
+ * Extract channel (arg 0) from group (arg 1).
+ */
+
+ case EXTR:
+ cp = xcp(gp, vec.m_arg[0]);
+ if (cp==NULL) {
+ u.u_error = ENXIO;
+ return;
+ }
+ if (cp->c_flags & ISGRP) {
+ (void) mxfalloc(((struct group *)cp)->g_file);
+ return;
+ }
+ if ((fp=cp->c_fy) != NULL) {
+ (void) mxfalloc(fp);
+ return;
+ }
+ if ((fp=falloc()) == NULL)
+ return;
+ fp->f_inode = gip;
+ gip->i_count++;
+ fp->f_un.f_chan = cp;
+ fp->f_flag = (vec.m_arg[2]) ?
+ (FREAD|FWRITE|FMPY) : (FREAD|FWRITE|FMPX);
+ cp->c_fy = fp;
+ return;
+
+ /*
+ * Make new chan on group (arg 1).
+ */
+
+ case CHAN:
+ if((gfp->f_flag&FMP)==FMP)cp = addch(gip, 0);
+ if(cp == NULL){
+ u.u_error = ENXIO;
+ return;
+ }
+ cp->c_flags = XGRP;
+ cp->c_fy = NULL;
+ cp->c_ttyp = cp->c_ottyp = (struct tty *)cp;
+ cp->c_line = cp->c_oline = mpxline;
+ u.u_r.r_val1 = cpx(cp);
+ return;
+
+ /*
+ * Connect fd (arg 0) to channel fd (arg 1).
+ * (arg 2 < 0) => fd to chan only
+ * (arg 2 > 0) => chan to fd only
+ * (arg 2 == 0) => both directions
+ */
+
+ case CONNECT:
+ if ((fp=getf(vec.m_arg[0]))==NULL)
+ return;
+ if ((chfp=getf(vec.m_arg[1]))==NULL)
+ return;
+ ip = fp->f_inode;
+ i = ip->i_mode&IFMT;
+ if (i!=IFCHR) {
+ u.u_error = ENXIO;
+ return;
+ }
+ dev = (dev_t)ip->i_un.i_rdev;
+ tp = cdevsw[major(dev)].d_ttys;
+ if (tp==NULL) {
+ u.u_error = ENXIO;
+ return;
+ }
+ tp = &tp[minor(dev)];
+ if (!(chfp->f_flag&FMPY)) {
+ u.u_error = ENXIO;
+ return;
+ }
+ cp = chfp->f_un.f_chan;
+ if (cp==NULL || cp->c_flags&PORT) {
+ u.u_error = ENXIO;
+ return;
+ }
+ i = vec.m_arg[2];
+ if (i>=0) {
+ cp->c_ottyp = tp;
+ cp->c_oline = tp->t_line;
+ }
+ if (i<=0) {
+ tp->t_chan = cp;
+ cp->c_ttyp = tp;
+ cp->c_line = tp->t_line;
+ }
+ u.u_r.r_val1 = 0;
+ return;
+
+ case NPGRP: {
+ register struct proc *pp;
+
+ if (gp != NULL) {
+ cp = xcp(gp, vec.m_arg[0]);
+ if (cp==NULL) {
+ u.u_error = ENXIO;
+ return;
+ }
+ }
+ pp = u.u_procp;
+ pp->p_pgrp = pp->p_pid;
+ if (vec.m_arg[2])
+ pp->p_pgrp = vec.m_arg[2];
+ if (gp != NULL)
+ cp->c_pgrp = pp->p_pgrp;
+ u.u_r.r_val1 = pp->p_pgrp;
+ return;
+ }
+
+ case CSIG:
+ cp = xcp(gp, vec.m_arg[0]);
+ if (cp==NULL) {
+ u.u_error = ENXIO;
+ return;
+ }
+ gsignal(cp->c_pgrp, vec.m_arg[2]);
+ u.u_r.r_val1 = vec.m_arg[2];
+ return;
+
+ case DEBUG:
+ i = vec.m_arg[0];
+ if (i<0 || i>NDEBUGS)
+ return;
+ mcdebugs[i] = vec.m_arg[1];
+ if (i==ALL)
+ for(i=0;i<NDEBUGS;i++)
+ mcdebugs[i] = vec.m_arg[1];
+ return;
+
+ default:
+ u.u_error = ENXIO;
+ return;
+ }
+
+}
+detach(cp)
+register struct chan *cp;
+{
+ register struct group *master,*sub;
+ register index;
+
+ if (cp==NULL)
+ return(0);
+ if (cp->c_flags&ISGRP) {
+ sub = (struct group *)cp;
+ master = sub->g_group; index = sub->g_index;
+ closef(sub->g_file);
+ if (master != NULL)
+ master->g_chans[index] = NULL;
+ return(0);
+ } else if (cp->c_flags&PORT && cp->c_ttyp != NULL) {
+ closef(cp->c_fy);
+ chdrain(cp);
+ chfree(cp);
+ return(0);
+ }
+ if (cp->c_flags & WCLOSE) {
+ if (cp->c_fy) {
+ if (cp->c_fy->f_count)
+ return(1);
+ chdrain(cp);
+ chfree(cp);
+ return(0);
+ }
+ }
+ cp->c_flags |= WCLOSE;
+ chwake(cp);
+ return(1);
+}
+
+
+mxfalloc(fp)
+register struct file *fp;
+{
+register i;
+
+ if (fp==NULL) {
+ u.u_error = ENXIO;
+ return(-1);
+ }
+ i = ufalloc();
+ if (i < 0)
+ return(i);
+ u.u_ofile[i] = fp;
+ fp->f_count++;
+ u.u_r.r_val1 = i;
+ return(i);
+}
+
+/*
+ * Grow a branch on a tree.
+ */
+
+mtree(sub,master)
+register struct group *sub, *master;
+{
+ register i;
+ int mtresiz, stresiz;
+
+ if ((mtresiz=mup(master,sub)) == NULL) {
+ u.u_error = ENXIO;
+ return(NULL);
+ }
+ if ((stresiz=mdown(sub,master)) <= 0) {
+ u.u_error = ENXIO;
+ return(NULL);
+ }
+ if (sub->g_group != NULL) {
+ u.u_error = ENXIO;
+ return(NULL);
+ }
+ if (stresiz+mtresiz > NLEVELS) {
+ u.u_error = ENXIO;
+ return(NULL);
+ }
+ for (i=0;i<NINDEX;i++) {
+ if (master->g_chans[i] != NULL)
+ continue;
+ master->g_chans[i] = (struct chan *)sub;
+ sub->g_group = master;
+ sub->g_index = i;
+ return(1);
+ }
+ u.u_error = ENXIO;
+ return(NULL);
+}
+
+mup(master,sub)
+struct group *master, *sub;
+{
+ register struct group *top;
+ register int depth;
+
+ depth = 1; top = master;
+ while (top->g_group) {
+ depth++;
+ top = top->g_group;
+ }
+ if(top == sub)
+ return(NULL);
+ return(depth);
+}
+
+
+mdown(sub,master)
+struct group *sub, *master;
+{
+ register int maxdepth, i, depth;
+
+ if(sub == (struct group *)NULL || (sub->g_state&ISGRP) == 0)
+ return(0);
+ if(sub == master)
+ return(-1);
+ maxdepth = 0;
+ for(i=0; i<NINDEX; i++) {
+ if((depth=mdown((struct group *)sub->g_chans[i],master)) == -1)
+ return(-1);
+ maxdepth = (depth>maxdepth) ? depth: maxdepth;
+ }
+ return(maxdepth+1);
+}
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