Author: kib
Date: Fri Dec  7 15:17:29 2018
New Revision: 341689
URL: https://svnweb.freebsd.org/changeset/base/341689

Log:
  Add new file handle system calls.
  
  Namely, getfhat(2), fhlink(2), fhlinkat(2), fhreadlink(2).  The
  syscalls are provided for a NFS userspace server (nfs-ganesha).
  
  Submitted by: Jack Halford <j...@gandi.net>
  Sponsored by: Gandi.net
  Tested by:    pho
  Feedback from:        brooks, markj
  MFC after:    1 week
  Differential revision:        https://reviews.freebsd.org/D18359

Added:
  head/lib/libc/sys/fhlink.2   (contents, props changed)
  head/lib/libc/sys/fhreadlink.2   (contents, props changed)
Modified:
  head/lib/libc/sys/Makefile.inc
  head/lib/libc/sys/Symbol.map
  head/lib/libc/sys/getfh.2
  head/sys/compat/freebsd32/syscalls.master
  head/sys/kern/syscalls.master
  head/sys/kern/vfs_syscalls.c
  head/sys/sys/mount.h

Modified: head/lib/libc/sys/Makefile.inc
==============================================================================
--- head/lib/libc/sys/Makefile.inc      Fri Dec  7 14:45:28 2018        
(r341688)
+++ head/lib/libc/sys/Makefile.inc      Fri Dec  7 15:17:29 2018        
(r341689)
@@ -184,7 +184,9 @@ MAN+=       abort2.2 \
        extattr_get_file.2 \
        fcntl.2 \
        ffclock.2 \
+       fhlink.2 \
        fhopen.2 \
+       fhreadlink.2 \
        flock.2 \
        fork.2 \
        fsync.2 \
@@ -395,7 +397,8 @@ MLINKS+=ffclock.2 ffclock_getcounter.2 \
 MLINKS+=fhopen.2 fhstat.2 fhopen.2 fhstatfs.2
 MLINKS+=fsync.2 fdatasync.2
 MLINKS+=getdirentries.2 getdents.2
-MLINKS+=getfh.2 lgetfh.2
+MLINKS+=getfh.2 lgetfh.2 \
+       getfh.2 getfhat.2
 MLINKS+=getgid.2 getegid.2
 MLINKS+=getitimer.2 setitimer.2
 MLINKS+=getlogin.2 getlogin_r.3

Modified: head/lib/libc/sys/Symbol.map
==============================================================================
--- head/lib/libc/sys/Symbol.map        Fri Dec  7 14:45:28 2018        
(r341688)
+++ head/lib/libc/sys/Symbol.map        Fri Dec  7 15:17:29 2018        
(r341689)
@@ -401,6 +401,13 @@ FBSD_1.5 {
        cpuset_setdomain;
 };
 
+FBSD_1.6 {
+       fhlink;
+       fhlinkat;
+       fhreadlink;
+       getfhat;
+};
+
 FBSDprivate_1.0 {
        ___acl_aclcheck_fd;
        __sys___acl_aclcheck_fd;

Added: head/lib/libc/sys/fhlink.2
==============================================================================
--- /dev/null   00:00:00 1970   (empty, because file is newly added)
+++ head/lib/libc/sys/fhlink.2  Fri Dec  7 15:17:29 2018        (r341689)
@@ -0,0 +1,268 @@
+.\" SPDX-License-Identifier: BSD-2-Clause
+.\"
+.\" Copyright (c) 2018 Gandi
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd November 29, 2018
+.Dt FHLINK 2
+.Os
+.Sh NAME
+.Nm fhlink ,
+.Nm fhlinkat
+.Nd make a hard file link
+.Sh LIBRARY
+.Lb libc
+.Sh SYNOPSIS
+.In unistd.h
+.Ft int
+.Fn fhlink "fhandle_t *fhp" "const char *to"
+.Ft int
+.Fn fhlinkat "fhandle_t *fhp" "int tofd" "const char *to"
+.Fc
+.Sh DESCRIPTION
+The
+.Fn fhlink
+system call
+atomically creates the specified directory entry (hard link)
+.Fa to
+with the attributes of the underlying object pointed at by
+.Fa fhp .
+If the link is successful: the link count of the underlying object
+is incremented;
+.Fa fhp
+and
+.Fa to
+share equal access and rights
+to the
+underlying object.
+.Pp
+If
+.Fa fhp
+is removed, the file
+.Fa to
+is not deleted and the link count of the
+underlying object is
+decremented.
+.Pp
+The object pointed at by the
+.Fa fhp
+argument
+must exist for the hard link to
+succeed and
+both
+.Fa fhp
+and
+.Fa to
+must be in the same file system.
+The
+.Fa fhp
+argument
+may not be a directory.
+.Pp
+The
+.Fn fhlinkat
+system call is equivalent to
+.Fa fhlink
+except in the case where
+.Fa to
+is a relative paths.
+In this case a relative path
+.Fa to
+is interpreted relative to
+the directory associated with the file descriptor
+.Fa tofd
+instead of the current working directory.
+.Pp
+Values for
+.Fa flag
+are constructed by a bitwise-inclusive OR of flags from the following
+list, defined in
+.In fcntl.h :
+.Bl -tag -width indent
+.It Dv AT_SYMLINK_FOLLOW
+If
+.Fa fhp
+names a symbolic link, a new link for the target of the symbolic link is
+created.
+.It Dv AT_BENEATH
+Only allow to link to a file which is beneath of the topping directory.
+See the description of the
+.Dv O_BENEATH
+flag in the
+.Xr open 2
+manual page.
+.El
+.Pp
+If
+.Fn fhlinkat
+is passed the special value
+.Dv AT_FDCWD
+in the
+.Fa tofd
+parameter, the current working directory is used for the
+.Fa to
+argument.
+If
+.Fa tofd
+has value
+.Dv AT_FDCWD ,
+the behavior is identical to a call to
+.Fn link .
+Unless
+.Fa flag
+contains the
+.Dv AT_SYMLINK_FOLLOW
+flag, if
+.Fa fhp
+names a symbolic link, a new link is created for the symbolic link
+.Fa fhp
+and not its target.
+.Sh RETURN VALUES
+.Rv -std link
+.Sh ERRORS
+The
+.Fn fhlink
+system call
+will fail and no link will be created if:
+.Bl -tag -width Er
+.It Bq Er ENOTDIR
+A component of
+.Fa to
+prefix is not a directory.
+.It Bq Er ENAMETOOLONG
+A component of
+.Fa to
+exceeded 255 characters,
+or entire length of
+.Fa to
+name exceeded 1023 characters.
+.It Bq Er ENOENT
+A component of
+.Fa to
+prefix does not exist.
+.It Bq Er EOPNOTSUPP
+The file system containing the file pointed at by
+.Fa fhp
+does not support links.
+.It Bq Er EMLINK
+The link count of the file pointed at by
+.Fa fhp
+would exceed 32767.
+.It Bq Er EACCES
+A component of 
+.Fa to
+prefix denies search permission.
+.It Bq Er EACCES
+The requested link requires writing in a directory with a mode
+that denies write permission.
+.It Bq Er ELOOP
+Too many symbolic links were encountered in translating one of the pathnames.
+.It Bq Er ENOENT
+The file pointed at by
+.Fa fhp
+does not exist.
+.It Bq Er EEXIST
+The link named by
+.Fa to
+does exist.
+.It Bq Er EPERM
+The file pointed at by
+.Fa fhp
+is a directory.
+.It Bq Er EPERM
+The file pointed at by
+.Fa fhp
+has its immutable or append-only flag set, see the
+.Xr chflags 2
+manual page for more information.
+.It Bq Er EPERM
+The parent directory of the file named by
+.Fa to
+has its immutable flag set.
+.It Bq Er EXDEV
+The link named by
+.Fa to
+and the file pointed at by
+.Fa fhp
+are on different file systems.
+.It Bq Er ENOSPC
+The directory in which the entry for the new link is being placed
+cannot be extended because there is no space left on the file
+system containing the directory.
+.It Bq Er EDQUOT
+The directory in which the entry for the new link
+is being placed cannot be extended because the
+user's quota of disk blocks on the file system
+containing the directory has been exhausted.
+.It Bq Er EIO
+An I/O error occurred while reading from or writing to
+the file system to make the directory entry.
+.It Bq Er EROFS
+The requested link requires writing in a directory on a read-only file
+system.
+.It Bq Er EFAULT
+One of the pathnames specified
+is outside the process's allocated address space.
+.It Bq Er ESTALE
+The file handle
+.Fa fhp
+is no longer valid
+.El
+.Pp
+In addition to the errors returned by the
+.Fn fhlink ,
+the
+.Fn fhlinkat
+system call may fail if:
+.Bl -tag -width Er
+.It Bq Er EBADF
+The
+.Fa fhp
+or
+.Fa to
+argument does not specify an absolute path and the
+.Fa tofd
+argument, is not
+.Dv AT_FDCWD
+nor a valid file descriptor open for searching.
+.It Bq Er EINVAL
+The value of the
+.Fa flag
+argument is not valid.
+.It Bq Er ENOTDIR
+The
+.Fa fhp
+or
+.Fa to
+argument is not an absolute path and
+.Fa tofd
+is not
+.Dv AT_FDCWD
+nor a file descriptor associated with a directory.
+.El
+.Sh SEE ALSO
+.Xr fhstat 2 ,
+.Xr fhreadlink 2 ,
+.Xr fhopen 2 ,

Added: head/lib/libc/sys/fhreadlink.2
==============================================================================
--- /dev/null   00:00:00 1970   (empty, because file is newly added)
+++ head/lib/libc/sys/fhreadlink.2      Fri Dec  7 15:17:29 2018        
(r341689)
@@ -0,0 +1,92 @@
+.\" SPDX-License-Identifier: BSD-2-Clause
+.\"
+.\" Copyright (c) 2018 Gandi
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd November 29, 2018
+.Dt FHREADLINK 2
+.Os
+.Sh NAME
+.Nm fhreadlink
+.Nd read value of a symbolic link
+.Sh LIBRARY
+.Lb libc
+.Sh SYNOPSIS
+.In sys/param.h
+.In sys/mount.h
+.Ft int
+.Fn fhreadlink "fhandle_t *fhp" "char *buf" "size_t bufsize"
+.Fc
+.Sh DESCRIPTION
+The
+.Fn fhreadlink
+system call
+places the contents of the symbolic link
+.Fa fhp
+in the buffer
+.Fa buf ,
+which has size
+.Fa bufsiz .
+The
+.Fn fhreadlink
+system call does not append a
+.Dv NUL
+character to
+.Fa buf .
+.Pp
+.Sh RETURN VALUES
+The call returns the count of characters placed in the buffer
+if it succeeds, or a \-1 if an error occurs, placing the error
+code in the global variable
+.Va errno .
+.Sh ERRORS
+The
+.Fn readlink
+system call
+will fail if:
+.Bl -tag -width Er
+.It Bq Er ENOENT
+The named file does not exist.
+.It Bq Er ELOOP
+Too many symbolic links were encountered in translating the file handle
+.Fa fhp .
+.It Bq Er EINVAL
+The named file is not a symbolic link.
+.It Bq Er EIO
+An I/O error occurred while reading from the file system.
+.It Bq Er EFAULT
+The
+.Fa buf
+argument
+extends outside the process's allocated address space.
+.It Bq Er ESTALE
+The file handle
+.Fa fhp
+is no longer valid
+.El
+.El
+.Sh SEE ALSO
+.Xr fhstat 2 ,
+.Xr fhlink 2 ,

Modified: head/lib/libc/sys/getfh.2
==============================================================================
--- head/lib/libc/sys/getfh.2   Fri Dec  7 14:45:28 2018        (r341688)
+++ head/lib/libc/sys/getfh.2   Fri Dec  7 15:17:29 2018        (r341689)
@@ -1,5 +1,6 @@
 .\" Copyright (c) 1989, 1991, 1993
 .\"    The Regents of the University of California.  All rights reserved.
+.\" Copyright (c) 2018 Gandi
 .\"
 .\" Redistribution and use in source and binary forms, with or without
 .\" modification, are permitted provided that the following conditions
@@ -28,12 +29,13 @@
 .\"    @(#)getfh.2     8.1 (Berkeley) 6/9/93
 .\" $FreeBSD$
 .\"
-.Dd April 14, 2011
+.Dd December 7, 2018
 .Dt GETFH 2
 .Os
 .Sh NAME
 .Nm getfh ,
-.Nm lgetfh
+.Nm lgetfh ,
+.Nm getfhat
 .Nd get file handle
 .Sh LIBRARY
 .Lb libc
@@ -44,6 +46,8 @@
 .Fn getfh "const char *path" "fhandle_t *fhp"
 .Ft int
 .Fn lgetfh "const char *path" "fhandle_t *fhp"
+.Ft int
+.Fn getfhat "int fd" "const char *path" "fhandle_t *fhp" "int flag"
 .Sh DESCRIPTION
 The
 .Fn getfh
@@ -51,6 +55,7 @@ system call
 returns a file handle for the specified file or directory
 in the file handle pointed to by
 .Fa fhp .
+.Pp
 The
 .Fn lgetfh
 system call is like
@@ -62,6 +67,85 @@ returns information about the link,
 while
 .Fn getfh
 returns information about the file the link references.
+.Pp
+The
+.Fn getfhat
+system call is equivalent to
+.Fn getfh
+and
+.Fn lgetfh
+except when the
+.Fa path
+specifies a relative or NULL path, or the
+.Dv AT_BENEATH
+flag is provided.
+For
+.Fn getfhat
+and relative or NULL
+.Fa path ,
+the status is retrieved from a file relative to
+the directory associated with the file descriptor
+.Fa fd
+instead of the current working directory.
+For
+.Dv AT_BENEATH
+and absolute
+.Fa path ,
+the status is retrieved from a file specified by the
+.Fa path ,
+but additional permission checks are performed, see below.
+.Pp
+The values for the
+.Fa flag
+are constructed by a bitwise-inclusive OR of flags from this list,
+defined in
+.In fcntl.h :
+.Bl -tag -width indent
+.It Dv AT_SYMLINK_NOFOLLOW
+If
+.Fa path
+names a symbolic link, the status of the symbolic link is returned.
+.It Dv AT_BENEATH
+Only stat files and directories below the topping directory.
+See the description of the
+.Dv O_BENEATH
+flag in the
+.Xr open 2
+manual page.
+.El
+.Pp
+If
+.Fn getfhat
+is passed the special value
+.Dv AT_FDCWD
+in the
+.Fa fd
+parameter, the current working directory is used and the behavior is
+identical to a call to
+.Fn getfth
+or
+.Fn lgetfh
+respectively, depending on whether or not the
+.Dv AT_SYMLINK_NOFOLLOW
+bit is set in
+.Fa flag .
+.Pp
+When
+.Fn getfhat
+is called with an absolute
+.Fa path
+without the
+.Dv AT_BENEATH
+flag, it ignores the
+.Fa fd
+argument.
+When
+.Dv AT_BENEATH
+is specified with an absolute
+.Fa path ,
+a directory passed by the
+.Fa fd
+argument is used as the topping point for the resolution.
 These system calls are restricted to the superuser.
 .Sh RETURN VALUES
 .Rv -std
@@ -99,11 +183,49 @@ The
 .Fa fhp
 argument
 points to an invalid address.
+.It Bq Er EFAULT
+The
+.Fa path
+argument
+points to an invalid address.
 .It Bq Er EIO
 An
 .Tn I/O
 error occurred while reading from or writing to the file system.
+.It Bq Er ESTALE
+The file handle
+.Fa fhp
+is no longer valid.
 .El
+.Pp
+In addition to the errors returned by
+.Fn getfh ,
+and
+.Fn lgetfh ,
+the
+.Fn getfhat
+system call may fail if:
+.Bl -tag -width Er
+.It Bq Er EBADF
+The
+.Fa path
+argument does not specify an absolute path and the
+.Fa fd
+argument, is neither
+.Dv AT_FDCWD
+nor a valid file descriptor open for searching.
+.It Bq Er EINVAL
+The value of the
+.Fa flag
+argument is not valid.
+.It Bq Er ENOTDIR
+The
+.Fa path
+argument is not an absolute path and
+.Fa fd
+is neither
+.Dv AT_FDCWD
+nor a file descriptor associated with a directory.
 .Sh SEE ALSO
 .Xr fhopen 2 ,
 .Xr open 2 ,

Modified: head/sys/compat/freebsd32/syscalls.master
==============================================================================
--- head/sys/compat/freebsd32/syscalls.master   Fri Dec  7 14:45:28 2018        
(r341688)
+++ head/sys/compat/freebsd32/syscalls.master   Fri Dec  7 15:17:29 2018        
(r341689)
@@ -1138,5 +1138,12 @@
                                    int policy); }
 563    AUE_NULL        NOPROTO { int getrandom(void *buf, size_t buflen, \
                                    unsigned int flags); }
+564    AUE_NULL        NOPROTO { int getfhat( int fd, char *path, \
+                                   struct fhandle *fhp, int flags); }
+565    AUE_NULL        NOPROTO { int fhlink( struct fhandle *fhp, const char 
*to ); }
+566    AUE_NULL        NOPROTO { int fhlinkat( struct fhandle *fhp, int tofd, \
+                                   const char *to); }
+567    AUE_NULL        NOPROTO { int fhreadlink( struct fhandle *fhp, char 
*buf, \
+                                   size_t bufsize); }
 
 ; vim: syntax=off

Modified: head/sys/kern/syscalls.master
==============================================================================
--- head/sys/kern/syscalls.master       Fri Dec  7 14:45:28 2018        
(r341688)
+++ head/sys/kern/syscalls.master       Fri Dec  7 15:17:29 2018        
(r341689)
@@ -3139,6 +3139,34 @@
                    unsigned int flags
                );
        }
+564    AUE_NULL        STD {
+               int getfhat(
+                   int fd,
+                   _In_z_ char *path,
+                   _Out_ struct fhandle *fhp,
+                   int flags
+               );
+       }
+565    AUE_NULL        STD {
+               int fhlink(
+                   _In_ struct fhandle *fhp,
+                   _In_z_ const char *to
+               );
+       }
+566    AUE_NULL        STD {
+               int fhlinkat(
+                   _In_ struct fhandle *fhp,
+                   int tofd,
+                   _In_z_ const char *to,
+               );
+       }
+567    AUE_NULL        STD {
+               int fhreadlink(
+                   _In_ struct fhandle *fhp,
+                   _Out_writes_(bufsize) char *buf,
+                   size_t bufsize
+               );
+       }
 
 ; Please copy any additions and changes to the following compatability tables:
 ; sys/compat/freebsd32/syscalls.master

Modified: head/sys/kern/vfs_syscalls.c
==============================================================================
--- head/sys/kern/vfs_syscalls.c        Fri Dec  7 14:45:28 2018        
(r341688)
+++ head/sys/kern/vfs_syscalls.c        Fri Dec  7 15:17:29 2018        
(r341689)
@@ -105,6 +105,14 @@ static int setutimes(struct thread *td, struct vnode *
     const struct timespec *, int, int);
 static int vn_access(struct vnode *vp, int user_flags, struct ucred *cred,
     struct thread *td);
+static int kern_fhlinkat(struct thread *td, int fd, const char *path,
+    enum uio_seg pathseg, fhandle_t *fhp);
+static int kern_getfhat(struct thread *td, int flags, int fd,
+    const char *path, enum uio_seg pathseg, fhandle_t *fhp);
+static int kern_readlink_vp(struct vnode *vp, char *buf, enum uio_seg bufseg,
+    size_t count, struct thread *td);
+static int kern_linkat_vp(struct thread *td, struct vnode *vp, int fd,
+    const char *path, enum uio_seg segflag);
 
 /*
  * Sync each mounted filesystem.
@@ -1492,28 +1500,38 @@ can_hardlink(struct vnode *vp, struct ucred *cred)
 
 int
 kern_linkat(struct thread *td, int fd1, int fd2, const char *path1,
-    const char *path2, enum uio_seg segflg, int follow)
+    const char *path2, enum uio_seg segflag, int follow)
 {
        struct vnode *vp;
-       struct mount *mp;
        struct nameidata nd;
        int error;
 
-again:
-       bwillwrite();
-       NDINIT_ATRIGHTS(&nd, LOOKUP, follow | AUDITVNODE1, segflg, path1, fd1,
-           &cap_linkat_source_rights, td);
+       do {
+               bwillwrite();
+               NDINIT_ATRIGHTS(&nd, LOOKUP, follow | AUDITVNODE1, segflag, 
path1, fd1,
+                   &cap_linkat_source_rights, td);
+               if ((error = namei(&nd)) != 0)
+                       return (error);
+               NDFREE(&nd, NDF_ONLY_PNBUF);
+               vp = nd.ni_vp;
+       } while ((error = kern_linkat_vp(td, vp, fd2, path2, segflag) == 
EAGAIN));
+       return (error);
+}
 
-       if ((error = namei(&nd)) != 0)
-               return (error);
-       NDFREE(&nd, NDF_ONLY_PNBUF);
-       vp = nd.ni_vp;
+static int
+kern_linkat_vp(struct thread *td, struct vnode *vp, int fd, const char *path,
+    enum uio_seg segflag)
+{
+       struct nameidata nd;
+       struct mount *mp;
+       int error;
+
        if (vp->v_type == VDIR) {
                vrele(vp);
                return (EPERM);         /* POSIX */
        }
        NDINIT_ATRIGHTS(&nd, CREATE,
-           LOCKPARENT | SAVENAME | AUDITVNODE2 | NOCACHE, segflg, path2, fd2,
+           LOCKPARENT | SAVENAME | AUDITVNODE2 | NOCACHE, segflag, path, fd,
            &cap_linkat_target_rights, td);
        if ((error = namei(&nd)) == 0) {
                if (nd.ni_vp != NULL) {
@@ -1557,7 +1575,7 @@ again:
                                    V_XSLEEP | PCATCH);
                                if (error != 0)
                                        return (error);
-                               goto again;
+                               return (EAGAIN);
                        }
                        error = VOP_LINK(nd.ni_dvp, vp, &nd.ni_cnd);
                        VOP_UNLOCK(vp, 0);
@@ -1568,7 +1586,7 @@ again:
                        vput(nd.ni_dvp);
                        NDFREE(&nd, NDF_ONLY_PNBUF);
                        vrele(vp);
-                       goto again;
+                       return (EAGAIN);
                }
        }
        vrele(vp);
@@ -2484,8 +2502,6 @@ kern_readlinkat(struct thread *td, int fd, const char 
     enum uio_seg pathseg, char *buf, enum uio_seg bufseg, size_t count)
 {
        struct vnode *vp;
-       struct iovec aiov;
-       struct uio auio;
        struct nameidata nd;
        int error;
 
@@ -2499,12 +2515,29 @@ kern_readlinkat(struct thread *td, int fd, const char 
                return (error);
        NDFREE(&nd, NDF_ONLY_PNBUF);
        vp = nd.ni_vp;
+
+       error = kern_readlink_vp(vp, buf, bufseg, count, td);
+       vput(vp);
+
+       return (error);
+}
+
+/*
+ * Helper function to readlink from a vnode
+ */
+static int
+kern_readlink_vp(struct vnode *vp, char *buf, enum uio_seg bufseg, size_t 
count,
+    struct thread *td)
+{
+       struct iovec aiov;
+       struct uio auio;
+       int error;
+
+       ASSERT_VOP_LOCKED(vp, "kern_readlink_vp(): vp not locked");
 #ifdef MAC
        error = mac_vnode_check_readlink(td->td_ucred, vp);
-       if (error != 0) {
-               vput(vp);
+       if (error != 0)
                return (error);
-       }
 #endif
        if (vp->v_type != VLNK && (vp->v_vflag & VV_READLINK) == 0)
                error = EINVAL;
@@ -2521,7 +2554,6 @@ kern_readlinkat(struct thread *td, int fd, const char 
                error = VOP_READLINK(vp, &auio, td->td_ucred);
                td->td_retval[0] = count - auio.uio_resid;
        }
-       vput(vp);
        return (error);
 }
 
@@ -4119,13 +4151,61 @@ getvnode(struct thread *td, int fd, cap_rights_t *righ
  */
 #ifndef _SYS_SYSPROTO_H_
 struct lgetfh_args {
-       char    *fname;
+       char *fname;
        fhandle_t *fhp;
 };
 #endif
 int
 sys_lgetfh(struct thread *td, struct lgetfh_args *uap)
 {
+
+       return (kern_getfhat(td, AT_SYMLINK_NOFOLLOW, AT_FDCWD, uap->fname,
+           UIO_USERSPACE, uap->fhp));
+}
+
+#ifndef _SYS_SYSPROTO_H_
+struct getfh_args {
+       char *fname;
+       fhandle_t *fhp;
+};
+#endif
+int
+sys_getfh(struct thread *td, struct getfh_args *uap)
+{
+
+       return (kern_getfhat(td, 0, AT_FDCWD, uap->fname, UIO_USERSPACE,
+           uap->fhp));
+}
+
+/*
+ * syscall for the rpc.lockd to use to translate an open descriptor into
+ * a NFS file handle.
+ *
+ * warning: do not remove the priv_check() call or this becomes one giant
+ * security hole.
+ */
+#ifndef _SYS_SYSPROTO_H_
+struct getfhat_args {
+       int fd;
+       char *path;
+       fhandle_t *fhp;
+       int flags;
+};
+#endif
+int
+sys_getfhat(struct thread *td, struct getfhat_args *uap)
+{
+
+       if ((uap->flags & ~(AT_SYMLINK_NOFOLLOW | AT_BENEATH)) != 0)
+           return (EINVAL);
+       return (kern_getfhat(td, uap->flags, uap->fd, uap->path ? uap->path : 
".",
+           UIO_USERSPACE, uap->fhp));
+}
+
+static int
+kern_getfhat(struct thread *td, int flags, int fd, const char *path,
+    enum uio_seg pathseg, fhandle_t *fhp)
+{
        struct nameidata nd;
        fhandle_t fh;
        struct vnode *vp;
@@ -4134,8 +4214,9 @@ sys_lgetfh(struct thread *td, struct lgetfh_args *uap)
        error = priv_check(td, PRIV_VFS_GETFH);
        if (error != 0)
                return (error);
-       NDINIT(&nd, LOOKUP, NOFOLLOW | LOCKLEAF | AUDITVNODE1, UIO_USERSPACE,
-           uap->fname, td);
+       NDINIT_AT(&nd, LOOKUP, ((flags & AT_SYMLINK_NOFOLLOW) != 0 ? NOFOLLOW :
+           FOLLOW) | ((flags & AT_BENEATH) != 0 ? BENEATH : 0) | LOCKLEAF |
+           AUDITVNODE1, pathseg, path, fd, td);
        error = namei(&nd);
        if (error != 0)
                return (error);
@@ -4146,40 +4227,96 @@ sys_lgetfh(struct thread *td, struct lgetfh_args *uap)
        error = VOP_VPTOFH(vp, &fh.fh_fid);
        vput(vp);
        if (error == 0)
-               error = copyout(&fh, uap->fhp, sizeof (fh));
+               error = copyout(&fh, fhp, sizeof (fh));
        return (error);
 }
 
 #ifndef _SYS_SYSPROTO_H_
-struct getfh_args {
-       char    *fname;
+struct fhlink_args {
        fhandle_t *fhp;
+       const char *to;
 };
 #endif
 int
-sys_getfh(struct thread *td, struct getfh_args *uap)
+sys_fhlink(struct thread *td, struct fhlink_args *uap)
 {
-       struct nameidata nd;
+
+       return (kern_fhlinkat(td, AT_FDCWD, uap->to, UIO_USERSPACE, uap->fhp));
+}
+
+#ifndef _SYS_SYSPROTO_H_
+struct fhlinkat_args {
+       fhandle_t *fhp;
+       int tofd;
+       const char *to;
+};
+#endif
+int
+sys_fhlinkat(struct thread *td, struct fhlinkat_args *uap)
+{
+
+       return (kern_fhlinkat(td, uap->tofd, uap->to, UIO_USERSPACE, uap->fhp));
+}
+
+static int
+kern_fhlinkat(struct thread *td, int fd, const char *path,
+    enum uio_seg pathseg, fhandle_t *fhp)
+{
        fhandle_t fh;
+       struct mount *mp;
        struct vnode *vp;
        int error;
 
        error = priv_check(td, PRIV_VFS_GETFH);
        if (error != 0)
                return (error);
-       NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNODE1, UIO_USERSPACE,
-           uap->fname, td);
-       error = namei(&nd);
+       error = copyin(fhp, &fh, sizeof(fh));
        if (error != 0)
                return (error);
-       NDFREE(&nd, NDF_ONLY_PNBUF);
-       vp = nd.ni_vp;
-       bzero(&fh, sizeof(fh));
-       fh.fh_fsid = vp->v_mount->mnt_stat.f_fsid;
-       error = VOP_VPTOFH(vp, &fh.fh_fid);
+       do {
+               bwillwrite();
+               if ((mp = vfs_busyfs(&fh.fh_fsid)) == NULL)
+                       return (ESTALE);
+               error = VFS_FHTOVP(mp, &fh.fh_fid, LK_SHARED, &vp);
+               vfs_unbusy(mp);
+               if (error != 0)
+                       return (error);
+               VOP_UNLOCK(vp, 0);
+       } while ((error = kern_linkat_vp(td, vp, fd, path, pathseg)) == EAGAIN);
+       return (error);
+}
+
+#ifndef _SYS_SYSPROTO_H_
+struct fhreadlink_args {
+       fhandle_t *fhp;
+       char *buf;
+       size_t bufsize;
+};
+#endif
+int
+sys_fhreadlink(struct thread *td, struct fhreadlink_args *uap)
+{
+       fhandle_t fh;
+       struct mount *mp;
+       struct vnode *vp;
+       int error;
+
+       error = priv_check(td, PRIV_VFS_GETFH);
+       if (error != 0)
+               return (error);
+       if (uap->bufsize > IOSIZE_MAX)
+               return (EINVAL);
+       error = copyin(uap->fhp, &fh, sizeof(fh));
+       if (error != 0)
+               return (error);
+       if ((mp = vfs_busyfs(&fh.fh_fsid)) == NULL)
+               return (ESTALE);
+       error = VFS_FHTOVP(mp, &fh.fh_fid, LK_SHARED, &vp);
+       vfs_unbusy(mp);
+       if (error != 0)
+               return (error);
+       error = kern_readlink_vp(vp, uap->buf, UIO_USERSPACE, uap->bufsize, td);
        vput(vp);
-       if (error == 0)
-               error = copyout(&fh, uap->fhp, sizeof (fh));
        return (error);
 }
 

Modified: head/sys/sys/mount.h
==============================================================================
--- head/sys/sys/mount.h        Fri Dec  7 14:45:28 2018        (r341688)
+++ head/sys/sys/mount.h        Fri Dec  7 15:17:29 2018        (r341689)
@@ -932,11 +932,15 @@ void      syncer_resume(void);
 struct stat;
 
 __BEGIN_DECLS
+int    fhlink(struct fhandle *, const char *);
+int    fhlinkat(struct fhandle *, int, const char *);
 int    fhopen(const struct fhandle *, int);
+int    fhreadlink(struct fhandle *, char *, size_t);
 int    fhstat(const struct fhandle *, struct stat *);
 int    fhstatfs(const struct fhandle *, struct statfs *);
 int    fstatfs(int, struct statfs *);
 int    getfh(const char *, fhandle_t *);
+int    getfhat(int, char *, struct fhandle *, int);
 int    getfsstat(struct statfs *, long, int);
 int    getmntinfo(struct statfs **, int);
 int    lgetfh(const char *, fhandle_t *);
_______________________________________________
svn-src-head@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/svn-src-head
To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"

Reply via email to