BSD 4_3_Reno release

[unix-history] / usr / src / sys / kern / vfs_vnops.c

diff --git a/usr/src/sys/kern/vfs_vnops.c b/usr/src/sys/kern/vfs_vnops.c
index 67693a4..ecfd253 100644 (file)
--- a/usr/src/sys/kern/vfs_vnops.c
+++ b/usr/src/sys/kern/vfs_vnops.c
@@ -1,288 +1,525 @@
-/*     vfs_vnops.c     4.22    82/02/27        */
-
-#include "../h/param.h"
-#include "../h/systm.h"
-#include "../h/dir.h"
-#include "../h/user.h"
-#include "../h/filsys.h"
-#include "../h/file.h"
-#include "../h/conf.h"
-#include "../h/inode.h"
-#include "../h/reg.h"
-#include "../h/acct.h"
-#include "../h/mount.h"
-#include "../h/socket.h"
-#include "../h/socketvar.h"
-#include "../h/proc.h"
+/*
+ * Copyright (c) 1982, 1986, 1989 Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution is only permitted until one year after the first shipment
+ * of 4.4BSD by the Regents.  Otherwise, redistribution and use in source and
+ * binary forms are permitted provided that: (1) source distributions retain
+ * this entire copyright notice and comment, and (2) distributions including
+ * binaries display the following acknowledgement:  This product includes
+ * software developed by the University of California, Berkeley and its
+ * contributors'' in the documentation or other materials provided with the
+ * distribution and in all advertising materials mentioning features or use
+ * of this software.  Neither the name of the University nor the names of
+ * its contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ *     @(#)vfs_vnops.c 7.23 (Berkeley) 6/28/90
+ */
+
+#include "param.h"
+#include "systm.h"
+#include "user.h"
+#include "kernel.h"
+#include "file.h"
+#include "stat.h"
+#include "buf.h"
+#include "proc.h"
+#include "uio.h"
+#include "socket.h"
+#include "socketvar.h"
+#include "mount.h"
+#include "vnode.h"
+#include "ioctl.h"
+#include "tty.h"
+
+int    vn_read(), vn_write(), vn_ioctl(), vn_select(), vn_close();
+struct         fileops vnops =
+       { vn_read, vn_write, vn_ioctl, vn_select, vn_close };

 
 /*
 
 /*

- * Convert a user supplied file descriptor into a pointer
- * to a file structure.  Only task is to check range of the descriptor.
- * Critical paths should use the GETF macro, defined in inline.h.
+ * Common code for vnode open operations.
+ * Check permissions, and call the VOP_OPEN or VOP_CREATE routine.

  */
  */

-struct file *
-getf(f)
-       register int f;
+vn_open(ndp, fmode, cmode)
+       register struct nameidata *ndp;
+       int fmode, cmode;

 {
 {

-       register struct file *fp;
+       register struct vnode *vp;
+       struct vattr vat;
+       struct vattr *vap = &vat;
+       int error;

 
 

-       if ((unsigned)f >= NOFILE || (fp = u.u_ofile[f]) == NULL) {
-               u.u_error = EBADF;
-               return (NULL);
+       if (fmode & FCREAT) {
+               ndp->ni_nameiop = CREATE | LOCKPARENT | LOCKLEAF;
+               if ((fmode & FEXCL) == 0)
+                       ndp->ni_nameiop |= FOLLOW;
+               if (error = namei(ndp))
+                       return (error);
+               if (ndp->ni_vp == NULL) {
+                       VATTR_NULL(vap);
+                       vap->va_type = VREG;
+                       vap->va_mode = cmode;
+                       if (error = VOP_CREATE(ndp, vap))
+                               return (error);
+                       fmode &= ~FTRUNC;
+                       vp = ndp->ni_vp;
+               } else {
+                       if (ndp->ni_dvp == ndp->ni_vp)
+                               vrele(ndp->ni_dvp);
+                       else
+                               vput(ndp->ni_dvp);
+                       ndp->ni_dvp = NULL;
+                       vp = ndp->ni_vp;
+                       if (fmode & FEXCL) {
+                               error = EEXIST;
+                               goto bad;
+                       }
+                       fmode &= ~FCREAT;
+               }
+       } else {
+               ndp->ni_nameiop = LOOKUP | FOLLOW | LOCKLEAF;
+               if (error = namei(ndp))
+                       return (error);
+               vp = ndp->ni_vp;
+       }
+       if (vp->v_type == VSOCK) {
+               error = EOPNOTSUPP;
+               goto bad;
+       }
+       if ((fmode & FCREAT) == 0) {
+               if (fmode & FREAD) {
+                       if (error = VOP_ACCESS(vp, VREAD, ndp->ni_cred))
+                               goto bad;
+               }
+               if (fmode & (FWRITE|FTRUNC)) {
+                       if (vp->v_type == VDIR) {
+                               error = EISDIR;
+                               goto bad;
+                       }
+                       if ((error = vn_writechk(vp)) ||
+                           (error = VOP_ACCESS(vp, VWRITE, ndp->ni_cred)))
+                               goto bad;
+               }
+       }
+       if (fmode & FTRUNC) {
+               VATTR_NULL(vap);
+               vap->va_size = 0;
+               if (error = VOP_SETATTR(vp, vap, ndp->ni_cred))
+                       goto bad;

        }
        }

-       return (fp);
+       VOP_UNLOCK(vp);
+       error = VOP_OPEN(vp, fmode, ndp->ni_cred);
+       if (error)
+               vrele(vp);
+       return (error);
+
+bad:
+       vput(vp);
+       return (error);

 }
 
 /*
 }
 
 /*

- * Internal form of close.
- * Decrement reference count on
- * file structure.
- * Also make sure the pipe protocol
- * does not constipate.
- *
- * Decrement reference count on the inode following
- * removal to the referencing file structure.
- * Call device handler on last close.
- * Nouser indicates that the user isn't available to present
- * errors to.
+ * Check for write permissions on the specified vnode.
+ * The read-only status of the file system is checked.
+ * Also, prototype text segments cannot be written.

  */
  */

-closef(fp, nouser)
-       register struct file *fp;
+vn_writechk(vp)
+       register struct vnode *vp;

 {
 {

-       register struct inode *ip;
-       register struct mount *mp;
-       int flag, mode;
-       dev_t dev;
-       register int (*cfunc)();

 
 

-       if (fp == NULL)
-               return;
-       if (fp->f_count > 1) {
-               fp->f_count--;
-               return;
-       }
-       flag = fp->f_flag;
-       if (flag & FSOCKET) {
-               u.u_error = 0;                  /* XXX */
-               soclose(fp->f_socket, nouser);
-               if (nouser == 0 && u.u_error)
-                       return;
-               fp->f_socket = 0;
-               fp->f_count = 0;
-               return;
-       }
-       ip = fp->f_inode;
-       dev = (dev_t)ip->i_un.i_rdev;
-       mode = ip->i_mode & IFMT;
-       ilock(ip);
-       iput(ip);
-       fp->f_count = 0;
+       /*
+        * Disallow write attempts on read-only file systems;
+        * unless the file is a socket or a block or character
+        * device resident on the file system.
+        */
+       if ((vp->v_mount->mnt_flag & MNT_RDONLY) && vp->v_type != VCHR &&
+           vp->v_type != VBLK && vp->v_type != VSOCK)
+               return (EROFS);
+       /*
+        * If there's shared text associated with
+        * the vnode, try to free it up once.  If
+        * we fail, we can't allow writing.
+        */
+       if (vp->v_flag & VTEXT)
+               xrele(vp);
+       if (vp->v_flag & VTEXT)
+               return (ETXTBSY);
+       return (0);
+}

 
 

-       switch (mode) {
+/*
+ * Vnode version of rdwri() for calls on file systems.
+ */
+vn_rdwr(rw, vp, base, len, offset, segflg, ioflg, cred, aresid)
+       enum uio_rw rw;
+       struct vnode *vp;
+       caddr_t base;
+       int len;
+       off_t offset;
+       enum uio_seg segflg;
+       int ioflg;
+       struct ucred *cred;
+       int *aresid;
+{
+       struct uio auio;
+       struct iovec aiov;
+       int error;

 
 

-       case IFCHR:
-               cfunc = cdevsw[major(dev)].d_close;
-               break;
+       if ((ioflg & IO_NODELOCKED) == 0)
+               VOP_LOCK(vp);
+       auio.uio_iov = &aiov;
+       auio.uio_iovcnt = 1;
+       aiov.iov_base = base;
+       aiov.iov_len = len;
+       auio.uio_resid = len;
+       auio.uio_offset = offset;
+       auio.uio_segflg = segflg;
+       auio.uio_rw = rw;
+       if (rw == UIO_READ)
+               error = VOP_READ(vp, &auio, ioflg, cred);
+       else
+               error = VOP_WRITE(vp, &auio, ioflg, cred);
+       if (aresid)
+               *aresid = auio.uio_resid;
+       else
+               if (auio.uio_resid && error == 0)
+                       error = EIO;
+       if ((ioflg & IO_NODELOCKED) == 0)
+               VOP_UNLOCK(vp);
+       return (error);
+}

 
 

-       case IFBLK:
-               /*
-                * We don't want to really close the device if it is mounted
-                */
-               for (mp = mount; mp < &mount[NMOUNT]; mp++)
-                       if (mp->m_bufp != NULL && mp->m_dev == dev)
-                               return;
-               cfunc = bdevsw[major(dev)].d_close;
-               break;
+vn_read(fp, uio, cred)
+       struct file *fp;
+       struct uio *uio;
+       struct ucred *cred;
+{
+       register struct vnode *vp = (struct vnode *)fp->f_data;
+       int count, error;
+
+       VOP_LOCK(vp);
+       uio->uio_offset = fp->f_offset;
+       count = uio->uio_resid;
+       error = VOP_READ(vp, uio, (fp->f_flag & FNDELAY) ? IO_NDELAY : 0, cred);
+       fp->f_offset += count - uio->uio_resid;
+       VOP_UNLOCK(vp);
+       return (error);
+}
+
+vn_write(fp, uio, cred)
+       struct file *fp;
+       struct uio *uio;
+       struct ucred *cred;
+{
+       register struct vnode *vp = (struct vnode *)fp->f_data;
+       int count, error, ioflag = 0;

 
 

+       if (vp->v_type == VREG && (fp->f_flag & FAPPEND))
+               ioflag |= IO_APPEND;
+       if (fp->f_flag & FNDELAY)
+               ioflag |= IO_NDELAY;
+       VOP_LOCK(vp);
+       uio->uio_offset = fp->f_offset;
+       count = uio->uio_resid;
+       error = VOP_WRITE(vp, uio, ioflag, cred);
+       if (ioflag & IO_APPEND)
+               fp->f_offset = uio->uio_offset;
+       else
+               fp->f_offset += count - uio->uio_resid;
+       VOP_UNLOCK(vp);
+       return (error);
+}
+
+/*
+ * Get stat info for a vnode.
+ */
+vn_stat(vp, sb)
+       struct vnode *vp;
+       register struct stat *sb;
+{
+       struct vattr vattr;
+       register struct vattr *vap;
+       int error;
+       u_short mode;
+
+       vap = &vattr;
+       error = VOP_GETATTR(vp, vap, u.u_cred);
+       if (error)
+               return (error);
+       /*
+        * Copy from vattr table
+        */
+       sb->st_dev = vap->va_fsid;
+       sb->st_ino = vap->va_fileid;
+       mode = vap->va_mode;
+       switch (vp->v_type) {
+       case VREG:
+               mode |= S_IFREG;
+               break;
+       case VDIR:
+               mode |= S_IFDIR;
+               break;
+       case VBLK:
+               mode |= S_IFBLK;
+               break;
+       case VCHR:
+               mode |= S_IFCHR;
+               break;
+       case VLNK:
+               mode |= S_IFLNK;
+               break;
+       case VSOCK:
+               mode |= S_IFSOCK;
+               break;
+       case VFIFO:
+               mode |= S_IFIFO;
+               break;

        default:
        default:

-               return;
-       }
-       for (fp = file; fp < fileNFILE; fp++) {
-               if (fp->f_flag & FSOCKET)
-                       continue;
-               if (fp->f_count && (ip = fp->f_inode) &&
-                   ip->i_un.i_rdev == dev && (ip->i_mode&IFMT) == mode)
-                       return;
-       }
-       if (mode == IFBLK) {
-               /*
-                * On last close of a block device (that isn't mounted)
-                * we must invalidate any in core blocks
-                */
-               bflush(dev);
-               binval(dev);
-       }
-       (*cfunc)(dev, flag, fp);
+               return (EBADF);
+       };
+       sb->st_mode = mode;
+       sb->st_nlink = vap->va_nlink;
+       sb->st_uid = vap->va_uid;
+       sb->st_gid = vap->va_gid;
+       sb->st_rdev = vap->va_rdev;
+       sb->st_size = vap->va_size;
+       sb->st_atime = vap->va_atime.tv_sec;
+       sb->st_spare1 = 0;
+       sb->st_mtime = vap->va_mtime.tv_sec;
+       sb->st_spare2 = 0;
+       sb->st_ctime = vap->va_ctime.tv_sec;
+       sb->st_spare3 = 0;
+       sb->st_blksize = vap->va_blocksize;
+       sb->st_flags = vap->va_flags;
+       sb->st_gen = vap->va_gen;
+       sb->st_blocks = vap->va_bytes / S_BLKSIZE;
+       return (0);

 }
 
 /*
 }
 
 /*

- * Openi called to allow handler
- * of special files to initialize and
- * validate before actual IO.
+ * Vnode ioctl call

  */
  */

-openi(ip, rw)
-       register struct inode *ip;
+vn_ioctl(fp, com, data)
+       struct file *fp;
+       int com;
+       caddr_t data;

 {
 {

-       dev_t dev;
-       register unsigned int maj;
+       register struct vnode *vp = ((struct vnode *)fp->f_data);
+       struct vattr vattr;
+       int error;

 
 

-       dev = (dev_t)ip->i_un.i_rdev;
-       maj = major(dev);
-       switch (ip->i_mode&IFMT) {
+       switch (vp->v_type) {

 
 

-       case IFCHR:
-               if (maj >= nchrdev)
-                       goto bad;
-               (*cdevsw[maj].d_open)(dev, rw);
-               break;
+       case VREG:
+       case VDIR:
+               if (com == FIONREAD) {
+                       if (error = VOP_GETATTR(vp, &vattr, u.u_cred))
+                               return (error);
+                       *(off_t *)data = vattr.va_size - fp->f_offset;
+                       return (0);
+               }
+               if (com == FIONBIO || com == FIOASYNC)  /* XXX */
+                       return (0);                     /* XXX */
+               /* fall into ... */

 
 

-       case IFBLK:
-               if (maj >= nblkdev)
-                       goto bad;
-               (*bdevsw[maj].d_open)(dev, rw);
+       default:
+               return (ENOTTY);
+
+       case VFIFO:
+       case VCHR:
+       case VBLK:
+               error = VOP_IOCTL(vp, com, data, fp->f_flag, u.u_cred);
+               if (error == 0 && com == TIOCSCTTY) {
+                       u.u_procp->p_session->s_ttyvp = vp;
+                       VREF(vp);
+               }
+               return (error);

        }
        }

-       return;
+}

 
 

-bad:
-       u.u_error = ENXIO;
+/*
+ * Vnode select call
+ */
+vn_select(fp, which)
+       struct file *fp;
+       int which;
+{
+       return (VOP_SELECT(((struct vnode *)fp->f_data), which, fp->f_flag,
+               u.u_cred));

 }
 
 /*
 }
 
 /*

- * Check mode permission on inode pointer.
- * Mode is READ, WRITE or EXEC.
- * In the case of WRITE, the
- * read-only status of the file
- * system is checked.
- * Also in WRITE, prototype text
- * segments cannot be written.
- * The mode is shifted to select
- * the owner/group/other fields.
- * The super user is granted all
- * permissions.
+ * Vnode close call

  */
  */

-access(ip, mode)
-       register struct inode *ip;
-       int mode;
+vn_close(fp)
+       register struct file *fp;

 {
 {

-       register m;
+       struct vnode *vp = ((struct vnode *)fp->f_data);
+       int error;
+
+       if (fp->f_flag & (FSHLOCK|FEXLOCK))
+               vn_unlock(fp, FSHLOCK|FEXLOCK);
+       /*
+        * Must delete vnode reference from this file entry
+        * before VOP_CLOSE, so that only other references
+        * will prevent close.
+        */
+       fp->f_data = (caddr_t) 0;
+       error = VOP_CLOSE(vp, fp->f_flag, u.u_cred);
+       vrele(vp);
+       return (error);
+}

 
 

-       m = mode;
-       if (m == IWRITE) {
-               if (getfs(ip->i_dev)->s_ronly != 0) {
-                       u.u_error = EROFS;
-                       return (1);
+/*
+ * Place an advisory lock on a vnode.
+ * !! THIS IMPLIES THAT ALL STATEFUL FILE SERVERS WILL USE file table entries
+ */
+vn_lock(fp, cmd)
+       register struct file *fp;
+       int cmd;
+{
+       register int priority = PLOCK;
+       register struct vnode *vp = (struct vnode *)fp->f_data;
+       int error = 0;
+       static char lockstr[] = "flock";
+
+       if ((cmd & LOCK_EX) == 0)
+               priority += 4;
+       priority |= PCATCH;
+
+       /*
+        * If there's a exclusive lock currently applied
+        * to the file, then we've gotta wait for the
+        * lock with everyone else.
+        */
+again:
+       while (vp->v_flag & VEXLOCK) {
+               /*
+                * If we're holding an exclusive
+                * lock, then release it.
+                */
+               if (fp->f_flag & FEXLOCK) {
+                       vn_unlock(fp, FEXLOCK);
+                       continue;

                }
                }

-               if (ip->i_flag&ITEXT)           /* try to free text */
-                       xrele(ip);
-               if (ip->i_flag & ITEXT) {
-                       u.u_error = ETXTBSY;
-                       return (1);
+               if (cmd & LOCK_NB)
+                       return (EWOULDBLOCK);
+               vp->v_flag |= VLWAIT;
+               if (error = tsleep((caddr_t)&vp->v_exlockc, priority,
+                   lockstr, 0))
+                       return (error);
+       }
+       if (error = 0 && (cmd & LOCK_EX) && (vp->v_flag & VSHLOCK)) {
+               /*
+                * Must wait for any shared locks to finish
+                * before we try to apply a exclusive lock.
+                *
+                * If we're holding a shared
+                * lock, then release it.
+                */
+               if (fp->f_flag & FSHLOCK) {
+                       vn_unlock(fp, FSHLOCK);
+                       goto again;

                }
                }

+               if (cmd & LOCK_NB)
+                       return (EWOULDBLOCK);
+               vp->v_flag |= VLWAIT;
+               if (error = tsleep((caddr_t)&vp->v_shlockc, PLOCK | PCATCH,
+                   lockstr, 0) == 0)
+                       return (error);

        }
        }

-       if (u.u_uid == 0)
-               return (0);
-       if (u.u_uid != ip->i_uid) {
-               m >>= 3;
-               if (ip->i_gid >= NGRPS ||
-                   (u.u_grps[ip->i_gid/(sizeof(int)*8)] &
-                    (1 << ip->i_gid%(sizeof(int)*8)) == 0))
-                       m >>= 3;
+       if (fp->f_flag & FEXLOCK)
+               panic("vn_lock");
+       if (cmd & LOCK_EX) {
+               cmd &= ~LOCK_SH;
+               vp->v_exlockc++;
+               vp->v_flag |= VEXLOCK;
+               fp->f_flag |= FEXLOCK;

        }
        }

-       if ((ip->i_mode&m) != 0)
-               return (0);
-       u.u_error = EACCES;
-       return (1);
+       if ((cmd & LOCK_SH) && (fp->f_flag & FSHLOCK) == 0) {
+               vp->v_shlockc++;
+               vp->v_flag |= VSHLOCK;
+               fp->f_flag |= FSHLOCK;
+       }
+       return (0);

 }
 
 /*
 }
 
 /*

- * Look up a pathname and test if
- * the resultant inode is owned by the
- * current user.
- * If not, try for super-user.
- * If permission is granted,
- * return inode pointer.
+ * Unlock a file.

  */
  */

-struct inode *
-owner(follow)
-       int follow;
+vn_unlock(fp, kind)
+       register struct file *fp;
+       int kind;

 {
 {

-       register struct inode *ip;
-
-       ip = namei(uchar, 0, follow);
-       if (ip == NULL)
-               return (NULL);
-       if (u.u_uid == ip->i_uid)
-               return (ip);
-       if (suser())
-               return (ip);
-       iput(ip);
-       return (NULL);
+       register struct vnode *vp = (struct vnode *)fp->f_data;
+       int flags;
+
+       kind &= fp->f_flag;
+       if (vp == NULL || kind == 0)
+               return;
+       flags = vp->v_flag;
+       if (kind & FSHLOCK) {
+               if ((flags & VSHLOCK) == 0)
+                       panic("vn_unlock: SHLOCK");
+               if (--vp->v_shlockc == 0) {
+                       vp->v_flag &= ~VSHLOCK;
+                       if (flags & VLWAIT)
+                               wakeup((caddr_t)&vp->v_shlockc);
+               }
+               fp->f_flag &= ~FSHLOCK;
+       }
+       if (kind & FEXLOCK) {
+               if ((flags & VEXLOCK) == 0)
+                       panic("vn_unlock: EXLOCK");
+               if (--vp->v_exlockc == 0) {
+                       vp->v_flag &= ~(VEXLOCK|VLWAIT);
+                       if (flags & VLWAIT)
+                               wakeup((caddr_t)&vp->v_exlockc);
+               }
+               fp->f_flag &= ~FEXLOCK;
+       }

 }
 
 /*
 }
 
 /*

- * Test if the current user is the
- * super user.
+ * vn_fhtovp() - convert a fh to a vnode ptr (optionally locked)
+ *     - look up fsid in mount list (if not found ret error)
+ *     - get vp by calling VFS_FHTOVP() macro
+ *     - if lockflag lock it with VOP_LOCK()

  */
  */

-suser()
+vn_fhtovp(fhp, lockflag, vpp)
+       fhandle_t *fhp;
+       int lockflag;
+       struct vnode **vpp;

 {
 {

+       register struct mount *mp;

 
 

-       if (u.u_uid == 0) {
-               u.u_acflag |= ASU;
-               return (1);
-       }
-       u.u_error = EPERM;
+       if ((mp = getvfs(&fhp->fh_fsid)) == NULL)
+               return (ESTALE);
+       if (VFS_FHTOVP(mp, &fhp->fh_fid, vpp))
+               return (ESTALE);
+       if (!lockflag)
+               VOP_UNLOCK(*vpp);

        return (0);
 }
 
 /*
        return (0);
 }
 
 /*

- * Allocate a user file descriptor.
+ * Noop

  */
  */

-ufalloc()
+vfs_noop()

 {
 {

-       register i;

 
 

-       for (i=0; i<NOFILE; i++)
-               if (u.u_ofile[i] == NULL) {
-                       u.u_r.r_val1 = i;
-                       u.u_pofile[i] = 0;
-                       return (i);
-               }
-       u.u_error = EMFILE;
-       return (-1);
+       return (ENXIO);

 }
 
 }
 

-struct file *lastf;

 /*
 /*

- * Allocate a user file descriptor
- * and a file structure.
- * Initialize the descriptor
- * to point at the file structure.
+ * Null op

  */
  */

-struct file *
-falloc()
+vfs_nullop()

 {
 {

-       register struct file *fp;
-       register i;
-
-       i = ufalloc();
-       if (i < 0)
-               return (NULL);
-       if (lastf == 0)
-               lastf = file;
-       for (fp = lastf; fp < fileNFILE; fp++)
-               if (fp->f_count == 0)
-                       goto slot;
-       for (fp = file; fp < lastf; fp++)
-               if (fp->f_count == 0)
-                       goto slot;
-       tablefull("file");
-       u.u_error = ENFILE;
-       return (NULL);
-slot:
-       u.u_ofile[i] = fp;
-       fp->f_count++;
-       fp->f_offset = 0;
-       fp->f_inode = 0;
-       lastf = fp + 1;
-       return (fp);
+
+       return (0);

 }
 }