/* This file contains the procedures for creating, opening, closing, and * seeking on files. * * The entry points into this file are * do_creat: perform the CREAT system call * do_open: perform the OPEN system call * do_mknod: perform the MKNOD system call * do_mkdir: perform the MKDIR system call * do_close: perform the CLOSE system call * do_lseek: perform the LSEEK system call * * Changes for VFS: * Jul 2006 (Balazs Gerofi) */ #include "fs.h" #include #include #include #include #include #include #include "file.h" #include "fproc.h" #include "lock.h" #include "param.h" #include #include #include "vnode.h" #include "vmnt.h" #define offset m2_l1 FORWARD _PROTOTYPE( int common_open, (int oflags, mode_t omode) ); FORWARD _PROTOTYPE( int pipe_open, (struct vnode *vp,mode_t bits,int oflags)); /*===========================================================================* * do_creat * *===========================================================================*/ PUBLIC int do_creat() { /* Perform the creat(name, mode) system call. */ int r; if (fetch_name(m_in.name, m_in.name_length, M3) != OK) return(err_code); r = common_open(O_WRONLY | O_CREAT | O_TRUNC, (mode_t) m_in.mode); return(r); } /*===========================================================================* * do_open * *===========================================================================*/ PUBLIC int do_open() { /* Perform the open(name, flags,...) system call. */ int create_mode = 0; /* is really mode_t but this gives problems */ int r; /* If O_CREAT is set, open has three parameters, otherwise two. */ if (m_in.mode & O_CREAT) { create_mode = m_in.c_mode; r = fetch_name(m_in.c_name, m_in.name1_length, M1); } else { r = fetch_name(m_in.name, m_in.name_length, M3); } if (r != OK) { return(err_code); /* name was bad */ } r = common_open(m_in.mode, create_mode); return(r); } /*===========================================================================* * common_open * *===========================================================================*/ PRIVATE int common_open(register int oflags, mode_t omode) { /* Common code from do_creat and do_open. */ int r, b, found; dev_t dev; mode_t bits; off_t pos; struct dmap *dp; struct filp *fil_ptr, *filp2; struct vnode *vp, *vp2; struct vmnt *vmp; char lastc[NAME_MAX]; int m; /* Request and response structures */ struct lookup_req lookup_req; struct open_req req; struct node_details res; /* Remap the bottom two bits of oflags. */ m = oflags & O_ACCMODE; switch(m) { case O_RDONLY: bits = R_BIT; break; case O_WRONLY: bits = W_BIT; break; case O_RDWR: bits = R_BIT | W_BIT; break; default: return EINVAL; } /* See if file descriptor and filp slots are available. */ if ((r = get_fd(0, bits, &m_in.fd, &fil_ptr)) != OK) return(r); /* See if a free vnode is available */ if ((vp = get_free_vnode()) == NIL_VNODE) { printf("VFS: no vnode available!\n"); return err_code; } /* If O_CREATE, set umask */ if (oflags & O_CREAT) { omode = I_REGULAR | (omode & ALL_MODES & fp->fp_umask); } /* Fill in lookup request fields */ lookup_req.path = user_fullpath; lookup_req.lastc = lastc; lookup_req.flags = oflags&O_CREAT ? (oflags&O_EXCL ? LAST_DIR : LAST_DIR_EATSYM) : EAT_PATH; /* Request lookup */ if ((r = lookup(&lookup_req, &res)) != OK) return r; /* Lookup was okay, fill in request fields for * the actual open request. */ req.inode_nr = res.inode_nr; req.fs_e = res.fs_e; req.oflags = oflags; req.omode = omode; req.lastc = lastc; req.uid = fp->fp_effuid; req.gid = fp->fp_effgid; /* Issue request */ if ((r = req_open(&req, &res)) != OK) return r; /* Check whether the vnode is already in use */ if ((vp2 = find_vnode(res.fs_e, res.inode_nr)) != NIL_VNODE) { vp = vp2; vp->v_size = res.fsize;; /* In case of trunc... */ vp->v_count++; } /* Otherwise use the free one */ else { vp->v_fs_e = res.fs_e; if ( (vmp = find_vmnt(vp->v_fs_e)) == NIL_VMNT) printf("VFS: vmnt not found by open()"); vp->v_dev = vmp->m_dev; vp->v_inode_nr = res.inode_nr; vp->v_mode = res.fmode; vp->v_size = res.fsize; vp->v_sdev = res.dev; vp->v_count = 1; vp->v_vmnt = vmp; vp->v_index = res.inode_index; } /* Claim the file descriptor and filp slot and fill them in. */ fp->fp_filp[m_in.fd] = fil_ptr; FD_SET(m_in.fd, &fp->fp_filp_inuse); fil_ptr->filp_count = 1; fil_ptr->filp_flags = oflags; fil_ptr->filp_vno = vp; switch (vp->v_mode & I_TYPE) { case I_CHAR_SPECIAL: /* Invoke the driver for special processing. */ r = dev_open(vp->v_sdev, who_e, bits | (oflags & ~O_ACCMODE)); break; case I_BLOCK_SPECIAL: /* Invoke the driver for special processing. */ r = dev_open(vp->v_sdev, who_e, bits | (oflags & ~O_ACCMODE)); /* Check whether the device is mounted or not */ found = 0; if (r == OK) { printf("VFS: opening block spec %d, handled by ", vp->v_sdev); for (vmp = &vmnt[0]; vmp < &vmnt[NR_MNTS]; ++vmp) { if (vmp->m_dev == vp->v_sdev) { found = 1; break; } } /* Who is going to be responsible for this device? */ if (found) { printf("the FS of the mounted partition...\n"); vp->v_bfs_e = vmp->m_fs_e; vp->v_blocksize - vmp->m_block_size; } else { /* To be handled in the root FS proc if not mounted */ printf("the root FS...\n"); vp->v_bfs_e = ROOT_FS_E; vp->v_blocksize = _MIN_BLOCK_SIZE; } /* Get the driver endpoint of the block spec device */ dp = &dmap[(vp->v_sdev >> MAJOR) & BYTE]; if (dp->dmap_driver == NONE) { printf("VFSblock_spec_open: driver not found for device %d\n", vp->v_sdev); r = EINVAL; break; } /* Send the driver endpoint (even if it is known already...) */ if ((r = req_newdriver(vp->v_bfs_e, vp->v_sdev, dp->dmap_driver)) != OK) { printf("VFSblock_spec_open: error sending driver endpoint\n"); } } break; case I_NAMED_PIPE: vp->v_pipe = I_PIPE; oflags |= O_APPEND; /* force append mode */ fil_ptr->filp_flags = oflags; r = pipe_open(vp, bits, oflags); if (r != ENXIO) { /* See if someone else is doing a rd or wt on * the FIFO. If so, use its filp entry so the * file position will be automatically shared. */ b = (bits & R_BIT ? R_BIT : W_BIT); fil_ptr->filp_count = 0; /* don't find self */ if ((filp2 = find_filp(vp, b)) != NIL_FILP) { /* Co-reader or writer found. Use it.*/ fp->fp_filp[m_in.fd] = filp2; filp2->filp_count++; filp2->filp_vno = vp; filp2->filp_flags = oflags; /* v_count was incremented after the vnode has * been found, i_count was incremented incorrectly * by eatpath in FS, not knowing that we were going to * use an existing filp entry. Correct this error. */ put_vnode(vp); } else { /* Nobody else found. Restore filp. */ fil_ptr->filp_count = 1; if (fil_ptr->filp_mode == R_BIT) fil_ptr->filp_pos = vp->v_pipe_rd_pos; else fil_ptr->filp_pos = vp->v_pipe_wr_pos; } } break; } /* If error, release inode. */ if (r != OK) { if (r == SUSPEND) return(r); /* Oops, just suspended */ fp->fp_filp[m_in.fd] = NIL_FILP; FD_CLR(m_in.fd, &fp->fp_filp_inuse); fil_ptr->filp_count= 0; put_vnode(vp); fil_ptr->filp_vno = NIL_VNODE; return(r); } return(m_in.fd); } /*===========================================================================* * pipe_open * *===========================================================================*/ PRIVATE int pipe_open(register struct vnode *vp, register mode_t bits, register int oflags) { /* This function is called from common_open. It checks if * there is at least one reader/writer pair for the pipe, if not * it suspends the caller, otherwise it revives all other blocked * processes hanging on the pipe. */ vp->v_pipe = I_PIPE; if((bits & (R_BIT|W_BIT)) == (R_BIT|W_BIT)) { printf("pipe opened RW.\n"); return ENXIO; } if (find_filp(vp, bits & W_BIT ? R_BIT : W_BIT) == NIL_FILP) { if (oflags & O_NONBLOCK) { if (bits & W_BIT) return(ENXIO); } else { suspend(XPOPEN); /* suspend caller */ return(SUSPEND); } } else if (susp_count > 0) {/* revive blocked processes */ release(vp, OPEN, susp_count); release(vp, CREAT, susp_count); } return(OK); } /*===========================================================================* * do_mknod * *===========================================================================*/ PUBLIC int do_mknod() { /* Perform the mknod(name, mode, addr) system call. */ register mode_t bits, mode_bits; char lastc[NAME_MAX]; /* last component of the path */ struct mknod_req req; struct lookup_req lookup_req; struct node_details res; int r; /* Only the super_user may make nodes other than fifos. */ mode_bits = (mode_t) m_in.mk_mode; /* mode of the inode */ if (!super_user && ((mode_bits & I_TYPE) != I_NAMED_PIPE)) return(EPERM); if (fetch_name(m_in.name1, m_in.name1_length, M1) != OK) return(err_code); bits = (mode_bits & I_TYPE) | (mode_bits & ALL_MODES & fp->fp_umask); /* Fill in lookup request fields */ lookup_req.path = user_fullpath; lookup_req.lastc = lastc; lookup_req.flags = LAST_DIR; /* Request lookup */ if ((r = lookup(&lookup_req, &res)) != OK) return r; /* Lookup was okay, fill in request fields for the actual * mknod request. */ req.fs_e = res.fs_e; req.inode_nr = res.inode_nr; req.rmode = bits; req.dev = m_in.mk_z0; req.lastc = lastc; req.uid = fp->fp_effuid; req.gid = fp->fp_effgid; /* Issue request */ return req_mknod(&req); } /*===========================================================================* * do_mkdir * *===========================================================================*/ PUBLIC int do_mkdir() { /* Perform the mkdir(name, mode) system call. */ mode_t bits; /* mode bits for the new inode */ char lastc[NAME_MAX]; struct mkdir_req req; struct lookup_req lookup_req; struct node_details res; int r; /*printf("VFS: mkdir() START:");*/ if (fetch_name(m_in.name1, m_in.name1_length, M1) != OK) return(err_code); bits = I_DIRECTORY | (m_in.mode & RWX_MODES & fp->fp_umask); /* Fill in lookup request fields */ lookup_req.path = user_fullpath; lookup_req.lastc = lastc; lookup_req.flags = LAST_DIR; /* Request lookup */ if ((r = lookup(&lookup_req, &res)) != OK) return r; /* Lookup was okay, fill in request message fields * for the actual mknod request. */ req.fs_e = res.fs_e; req.d_inode_nr = res.inode_nr; req.rmode = bits; req.lastc = lastc; req.uid = fp->fp_effuid; req.gid = fp->fp_effgid; /* Issue request */ return req_mkdir(&req); } /*===========================================================================* * do_lseek * *===========================================================================*/ PUBLIC int do_lseek() { /* Perform the lseek(ls_fd, offset, whence) system call. */ register struct filp *rfilp; register off_t pos; struct node_req req; int r; /* Check to see if the file descriptor is valid. */ if ( (rfilp = get_filp(m_in.ls_fd)) == NIL_FILP) return(err_code); /* No lseek on pipes. */ if (rfilp->filp_vno->v_pipe == I_PIPE) return(ESPIPE); /* The value of 'whence' determines the start position to use. */ switch(m_in.whence) { case SEEK_SET: pos = 0; break; case SEEK_CUR: pos = rfilp->filp_pos; break; case SEEK_END: pos = rfilp->filp_vno->v_size; break; default: return(EINVAL); } /* Check for overflow. */ if (((long)m_in.offset > 0) && ((long)(pos + m_in.offset) < (long)pos)) return(EINVAL); if (((long)m_in.offset < 0) && ((long)(pos + m_in.offset) > (long)pos)) return(EINVAL); pos = pos + m_in.offset; if (pos != rfilp->filp_pos) { /* Inhibit read ahead request */ /* Fill in request message */ req.fs_e = rfilp->filp_vno->v_fs_e; req.inode_nr = rfilp->filp_vno->v_inode_nr; /* Issue request */ if ((r = req_inhibread(&req)) != OK) return r; } rfilp->filp_pos = pos; m_out.reply_l1 = pos; /* insert the long into the output message */ return(OK); } /*===========================================================================* * do_close * *===========================================================================*/ PUBLIC int do_close() { /* Perform the close(fd) system call. */ return close_fd(fp, m_in.fd); } /*===========================================================================* * close_fd * *===========================================================================*/ PUBLIC int close_fd(rfp, fd_nr) struct fproc *rfp; int fd_nr; { /* Perform the close(fd) system call. */ register struct filp *rfilp; register struct vnode *vp; struct file_lock *flp; int rw, mode_word, lock_count; dev_t dev; /* First locate the vnode that belongs to the file descriptor. */ if ( (rfilp = get_filp2(rfp, fd_nr)) == NIL_FILP) return(err_code); vp = rfilp->filp_vno; if (rfilp->filp_count - 1 == 0 && rfilp->filp_mode != FILP_CLOSED) { /* Check to see if the file is special. */ mode_word = vp->v_mode & I_TYPE; if (mode_word == I_CHAR_SPECIAL || mode_word == I_BLOCK_SPECIAL) { dev = (dev_t) vp->v_sdev; if (mode_word == I_BLOCK_SPECIAL) { /* Invalidate cache entries unless special is mounted * or ROOT */ req_sync(vp->v_bfs_e); printf("VFSclose: closed block spec %d\n", dev); } /* Do any special processing on device close. */ dev_close(dev); } } /* If the inode being closed is a pipe, release everyone hanging on it. */ if (vp->v_pipe == I_PIPE) { rw = (rfilp->filp_mode & R_BIT ? WRITE : READ); release(vp, rw, NR_PROCS); } /* If a write has been done, the inode is already marked as DIRTY. */ if (--rfilp->filp_count == 0) { if (vp->v_pipe == I_PIPE && vp->v_count > 1) { /* Save the file position in the v-node in case needed later. * The read and write positions are saved separately. */ if (rfilp->filp_mode == R_BIT) vp->v_pipe_rd_pos = rfilp->filp_pos; else vp->v_pipe_wr_pos = rfilp->filp_pos; } else { /* Otherwise zero the pipe position fields */ vp->v_pipe_rd_pos = 0; vp->v_pipe_wr_pos = 0; } put_vnode(rfilp->filp_vno); } FD_CLR(fd_nr, &rfp->fp_cloexec_set); rfp->fp_filp[fd_nr] = NIL_FILP; FD_CLR(fd_nr, &rfp->fp_filp_inuse); /* Check to see if the file is locked. If so, release all locks. */ if (nr_locks == 0) return(OK); lock_count = nr_locks; /* save count of locks */ for (flp = &file_lock[0]; flp < &file_lock[NR_LOCKS]; flp++) { if (flp->lock_type == 0) continue; /* slot not in use */ if (flp->lock_vnode == vp && flp->lock_pid == rfp->fp_pid) { flp->lock_type = 0; nr_locks--; } } if (nr_locks < lock_count) lock_revive(); /* lock released */ return(OK); }