UNIX 6th Ed. - /usr/sys/ken/sys3.c

   1: #
   2: /*
   3:  */
   4: 
   5: #include "../param.h"
   6: #include "../systm.h"
   7: #include "../reg.h"
   8: #include "../buf.h"
   9: #include "../filsys.h"
  10: #include "../user.h"
  11: #include "../inode.h"
  12: #include "../file.h"
  13: #include "../conf.h"
  14: 
  15: /*
  16:  * the fstat system call.
  17:  */
  18: fstat()
  19: {
  20:     register *fp;
  21: 
  22:     fp = getf(u.u_ar0[R0]);
  23:     if(fp == NULL)
  24:         return;
  25:     stat1(fp->f_inode, u.u_arg[0]);
  26: }
  27: 
  28: /*
  29:  * the stat system call.
  30:  */
  31: stat()
  32: {
  33:     register ip;
  34:     extern uchar;
  35: 
  36:     ip = namei(&uchar, 0);
  37:     if(ip == NULL)
  38:         return;
  39:     stat1(ip, u.u_arg[1]);
  40:     iput(ip);
  41: }
  42: 
  43: /*
  44:  * The basic routine for fstat and stat:
  45:  * get the inode and pass appropriate parts back.
  46:  */
  47: stat1(ip, ub)
  48: int *ip;
  49: {
  50:     register i, *bp, *cp;
  51: 
  52:     iupdat(ip, time);
  53:     bp = bread(ip->i_dev, ldiv(ip->i_number+31, 16));
  54:     cp = bp->b_addr + 32*lrem(ip->i_number+31, 16) + 24;
  55:     ip = &(ip->i_dev);
  56:     for(i=0; i<14; i++) {
  57:         suword(ub, *ip++);
  58:         ub =+ 2;
  59:     }
  60:     for(i=0; i<4; i++) {
  61:         suword(ub, *cp++);
  62:         ub =+ 2;
  63:     }
  64:     brelse(bp);
  65: }
  66: 
  67: /*
  68:  * the dup system call.
  69:  */
  70: dup()
  71: {
  72:     register i, *fp;
  73: 
  74:     fp = getf(u.u_ar0[R0]);
  75:     if(fp == NULL)
  76:         return;
  77:     if ((i = ufalloc()) < 0)
  78:         return;
  79:     u.u_ofile[i] = fp;
  80:     fp->f_count++;
  81: }
  82: 
  83: /*
  84:  * the mount system call.
  85:  */
  86: smount()
  87: {
  88:     int d;
  89:     register *ip;
  90:     register struct mount *mp, *smp;
  91:     extern uchar;
  92: 
  93:     d = getmdev();
  94:     if(u.u_error)
  95:         return;
  96:     u.u_dirp = u.u_arg[1];
  97:     ip = namei(&uchar, 0);
  98:     if(ip == NULL)
  99:         return;
 100:     if(ip->i_count!=1 || (ip->i_mode&(IFBLK&IFCHR))!=0)
 101:         goto out;
 102:     smp = NULL;
 103:     for(mp = &mount[0]; mp < &mount[NMOUNT]; mp++) {
 104:         if(mp->m_bufp != NULL) {
 105:             if(d == mp->m_dev)
 106:                 goto out;
 107:         } else
 108:         if(smp == NULL)
 109:             smp = mp;
 110:     }
 111:     if(smp == NULL)
 112:         goto out;
 113:     (*bdevsw[d.d_major].d_open)(d, !u.u_arg[2]);
 114:     if(u.u_error)
 115:         goto out;
 116:     mp = bread(d, 1);
 117:     if(u.u_error) {
 118:         brelse(mp);
 119:         goto out1;
 120:     }
 121:     smp->m_inodp = ip;
 122:     smp->m_dev = d;
 123:     smp->m_bufp = getblk(NODEV);
 124:     bcopy(mp->b_addr, smp->m_bufp->b_addr, 256);
 125:     smp = smp->m_bufp->b_addr;
 126:     smp->s_ilock = 0;
 127:     smp->s_flock = 0;
 128:     smp->s_ronly = u.u_arg[2] & 1;
 129:     brelse(mp);
 130:     ip->i_flag =| IMOUNT;
 131:     prele(ip);
 132:     return;
 133: 
 134: out:
 135:     u.u_error = EBUSY;
 136: out1:
 137:     iput(ip);
 138: }
 139: 
 140: /*
 141:  * the umount system call.
 142:  */
 143: sumount()
 144: {
 145:     int d;
 146:     register struct inode *ip;
 147:     register struct mount *mp;
 148: 
 149:     update();
 150:     d = getmdev();
 151:     if(u.u_error)
 152:         return;
 153:     for(mp = &mount[0]; mp < &mount[NMOUNT]; mp++)
 154:         if(mp->m_bufp!=NULL && d==mp->m_dev)
 155:             goto found;
 156:     u.u_error = EINVAL;
 157:     return;
 158: 
 159: found:
 160:     for(ip = &inode[0]; ip < &inode[NINODE]; ip++)
 161:         if(ip->i_number!=0 && d==ip->i_dev) {
 162:             u.u_error = EBUSY;
 163:             return;
 164:         }
 165:     (*bdevsw[d.d_major].d_close)(d, 0);
 166:     ip = mp->m_inodp;
 167:     ip->i_flag =& ~IMOUNT;
 168:     iput(ip);
 169:     ip = mp->m_bufp;
 170:     mp->m_bufp = NULL;
 171:     brelse(ip);
 172: }
 173: 
 174: /*
 175:  * Common code for mount and umount.
 176:  * Check that the user's argument is a reasonable
 177:  * thing on which to mount, and return the device number if so.
 178:  */
 179: getmdev()
 180: {
 181:     register d, *ip;
 182:     extern uchar;
 183: 
 184:     ip = namei(&uchar, 0);
 185:     if(ip == NULL)
 186:         return;
 187:     if((ip->i_mode&IFMT) != IFBLK)
 188:         u.u_error = ENOTBLK;
 189:     d = ip->i_addr[0];
 190:     if(ip->i_addr[0].d_major >= nblkdev)
 191:         u.u_error = ENXIO;
 192:     iput(ip);
 193:     return(d);
 194: }

Defined functions