#include "../h/param.h" #include "../h/systm.h" #include "../h/inode.h" #include "../h/dir.h" #include "../h/user.h" #include "../h/buf.h" #include "../h/conf.h" /* * Read the file corresponding to * the inode pointed at by the argument. * The actual read arguments are found * in the variables: * u_base core address for destination * u_offset byte offset in file * u_count number of bytes to read * u_segflg read to kernel/user/user I */ readi(ip) register struct inode *ip; { struct buf *bp; dev_t dev; daddr_t lbn, bn; off_t diff; register on, n; register type; extern int mem_no; if(u.u_count == 0) return; dev = (dev_t)ip->i_un.i_rdev; if(u.u_offset < 0 && ((ip->i_mode&IFMT) != IFCHR || mem_no != major(dev)) ) { u.u_error = EINVAL; return; } ip->i_flag |= IACC; type = ip->i_mode&IFMT; if (type==IFCHR || type==IFMPC) { (*cdevsw[major(dev)].d_read)(dev); return; } do { lbn = bn = u.u_offset >> BSHIFT; on = u.u_offset & BMASK; n = min((unsigned)(BSIZE-on), u.u_count); if(type!=IFBLK && type!=IFMPB) { diff = ip->i_size - u.u_offset; if(diff <= 0) return; if(diff < n) n = diff; bn = bmap(ip, bn, B_READ); if(u.u_error) return; dev = ip->i_dev; } else rablock = bn+1; if ((long)bn<0) { bp = geteblk(); clrbuf(bp); } else if (ip->i_un.i_lastr+1 == lbn) bp = breada(dev, bn, rablock); else bp = bread(dev, bn); ip->i_un.i_lastr = lbn; n = min((unsigned)n, BSIZE-bp->b_resid); if (n!=0) { iomove(bp->b_un.b_addr+on, n, B_READ); } brelse(bp); } while(u.u_error==0 && u.u_count!=0 && n>0); } /* * Write the file corresponding to * the inode pointed at by the argument. * The actual write arguments are found * in the variables: * u_base core address for source * u_offset byte offset in file * u_count number of bytes to write * u_segflg write to kernel/user/user I */ writei(ip) register struct inode *ip; { struct buf *bp; dev_t dev; daddr_t bn; register n, on; register type; extern int mem_no; dev = (dev_t)ip->i_un.i_rdev; if(u.u_offset < 0 && ((ip->i_mode&IFMT) != IFCHR || mem_no != major(dev)) ) { u.u_error = EINVAL; return; } type = ip->i_mode&IFMT; if (type==IFCHR || type==IFMPC) { ip->i_flag |= IUPD|ICHG; (*cdevsw[major(dev)].d_write)(dev); return; } if (u.u_count == 0) return; do { bn = u.u_offset >> BSHIFT; on = u.u_offset & BMASK; n = min((unsigned)BSIZE-on, u.u_count); if(type!=IFBLK && type!=IFMPB) { bn = bmap(ip, bn, B_WRITE); if((long)bn<0) return; dev = ip->i_dev; } if(n == BSIZE) bp = getblk(dev, bn); else bp = bread(dev, bn); iomove(bp->b_un.b_addr+on, n, B_WRITE); if(u.u_error != 0) brelse(bp); else bdwrite(bp); if(u.u_offset > ip->i_size && (type==IFDIR || type==IFREG)) ip->i_size = u.u_offset; ip->i_flag |= IUPD|ICHG; } while(u.u_error==0 && u.u_count!=0); } /* * Return the logical maximum * of the 2 arguments. */ max(a, b) unsigned a, b; { if(a > b) return(a); return(b); } /* * Return the logical minimum * of the 2 arguments. */ min(a, b) unsigned a, b; { if(a < b) return(a); return(b); } /* * Move n bytes at byte location * &bp->b_un.b_addr[o] to/from (flag) the * user/kernel (u.segflg) area starting at u.base. * Update all the arguments by the number * of bytes moved. */ iomove(cp, n, flag) register caddr_t cp; register n; { register t; if (n==0) return; if(u.u_segflg != 1) { if (flag==B_WRITE) t = copyin(u.u_base, (caddr_t)cp, n); else t = copyout((caddr_t)cp, u.u_base, n); if (t) { u.u_error = EFAULT; return; } } else if (flag == B_WRITE) bcopy(u.u_base,(caddr_t)cp,n); else bcopy((caddr_t)cp,u.u_base,n); u.u_base += n; u.u_offset += n; u.u_count -= n; return; }