minix/servers/vfs/stadir.c
Thomas Veerman 13ef7f1f38 Prepare VFS to support back calls from PFS. For security reasons and to support
file descriptor passing, PFS does some back calls to VFS. For example, to
verify the validity of a path provided by a process and to tell VFS it must
copy file descriptors from one process to another.
2010-08-30 13:44:07 +00:00

224 lines
6.8 KiB
C

/* This file contains the code for performing four system calls relating to
* status and directories.
*
* The entry points into this file are
* do_chdir: perform the CHDIR system call
* do_chroot: perform the CHROOT system call
* do_lstat: perform the LSTAT system call
* do_stat: perform the STAT system call
* do_fstat: perform the FSTAT system call
* do_fstatfs: perform the FSTATFS system call
* do_statvfs: perform the STATVFS system call
* do_fstatvfs: perform the FSTATVFS system call
*/
#include "fs.h"
#include <sys/stat.h>
#include <sys/statfs.h>
#include <minix/com.h>
#include <minix/u64.h>
#include <string.h>
#include "file.h"
#include "fproc.h"
#include "param.h"
#include <minix/vfsif.h>
#include "vnode.h"
#include "vmnt.h"
FORWARD _PROTOTYPE( int change, (struct vnode **iip, char *name_ptr, int len));
FORWARD _PROTOTYPE( int change_into, (struct vnode **iip, struct vnode *vp));
/*===========================================================================*
* do_fchdir *
*===========================================================================*/
PUBLIC int do_fchdir()
{
/* Change directory on already-opened fd. */
struct filp *rfilp;
/* Is the file descriptor valid? */
if ((rfilp = get_filp(m_in.fd)) == NULL) return(err_code);
dup_vnode(rfilp->filp_vno); /* Change into expects a reference. */
return change_into(&fp->fp_wd, rfilp->filp_vno);
}
/*===========================================================================*
* do_chdir *
*===========================================================================*/
PUBLIC int do_chdir()
{
/* Perform the chdir(name) system call. */
return change(&fp->fp_wd, m_in.name, m_in.name_length);
}
/*===========================================================================*
* do_chroot *
*===========================================================================*/
PUBLIC int do_chroot()
{
/* Perform the chroot(name) system call. */
if (!super_user) return(EPERM); /* only su may chroot() */
return change(&fp->fp_rd, m_in.name, m_in.name_length);
}
/*===========================================================================*
* change *
*===========================================================================*/
PRIVATE int change(iip, name_ptr, len)
struct vnode **iip; /* pointer to the inode pointer for the dir */
char *name_ptr; /* pointer to the directory name to change to */
int len; /* length of the directory name string */
{
/* Do the actual work for chdir() and chroot(). */
struct vnode *vp;
/* Try to open the directory */
if (fetch_name(name_ptr, len, M3) != OK) return(err_code);
if ((vp = eat_path(PATH_NOFLAGS, fp)) == NULL) return(err_code);
return change_into(iip, vp);
}
/*===========================================================================*
* change_into *
*===========================================================================*/
PRIVATE int change_into(iip, vp)
struct vnode **iip; /* pointer to the inode pointer for the dir */
struct vnode *vp; /* this is what the inode has to become */
{
int r;
/* It must be a directory and also be searchable */
if ((vp->v_mode & I_TYPE) != I_DIRECTORY)
r = ENOTDIR;
else
r = forbidden(vp, X_BIT); /* Check if dir is searchable*/
/* If error, return vnode */
if (r != OK) {
put_vnode(vp);
return(r);
}
/* Everything is OK. Make the change. */
put_vnode(*iip); /* release the old directory */
*iip = vp; /* acquire the new one */
return(OK);
}
/*===========================================================================*
* do_stat *
*===========================================================================*/
PUBLIC int do_stat()
{
/* Perform the stat(name, buf) system call. */
int r;
struct vnode *vp;
if (fetch_name(m_in.name1, m_in.name1_length, M1) != OK) return(err_code);
if ((vp = eat_path(PATH_NOFLAGS, fp)) == NULL) return(err_code);
r = req_stat(vp->v_fs_e, vp->v_inode_nr, who_e, m_in.name2, 0);
put_vnode(vp);
return r;
}
/*===========================================================================*
* do_fstat *
*===========================================================================*/
PUBLIC int do_fstat()
{
/* Perform the fstat(fd, buf) system call. */
register struct filp *rfilp;
int pipe_pos = 0;
/* Is the file descriptor valid? */
if ((rfilp = get_filp(m_in.fd)) == NULL) return(err_code);
/* If we read from a pipe, send position too */
if (rfilp->filp_vno->v_pipe == I_PIPE) {
if (rfilp->filp_mode & R_BIT)
if (ex64hi(rfilp->filp_pos) != 0) {
panic("do_fstat: bad position in pipe");
}
pipe_pos = ex64lo(rfilp->filp_pos);
}
return req_stat(rfilp->filp_vno->v_fs_e, rfilp->filp_vno->v_inode_nr,
who_e, m_in.buffer, pipe_pos);
}
/*===========================================================================*
* do_fstatfs *
*===========================================================================*/
PUBLIC int do_fstatfs()
{
/* Perform the fstatfs(fd, buf) system call. */
struct filp *rfilp;
/* Is the file descriptor valid? */
if( (rfilp = get_filp(m_in.fd)) == NULL) return(err_code);
return req_fstatfs(rfilp->filp_vno->v_fs_e, who_e, m_in.buffer);
}
/*===========================================================================*
* do_statvfs *
*===========================================================================*/
PUBLIC int do_statvfs()
{
/* Perform the stat(name, buf) system call. */
int r;
struct vnode *vp;
if (fetch_name(m_in.STATVFS_NAME, m_in.STATVFS_LEN, M1) != OK) return(err_code);
if ((vp = eat_path(PATH_NOFLAGS, fp)) == NULL) return(err_code);
r = req_statvfs(vp->v_fs_e, who_e, m_in.STATVFS_BUF);
put_vnode(vp);
return r;
}
/*===========================================================================*
* do_fstatvfs *
*===========================================================================*/
PUBLIC int do_fstatvfs()
{
/* Perform the fstat(fd, buf) system call. */
register struct filp *rfilp;
/* Is the file descriptor valid? */
if ((rfilp = get_filp(m_in.FSTATVFS_FD)) == NULL) return(err_code);
return req_statvfs(rfilp->filp_vno->v_fs_e, who_e, m_in.FSTATVFS_BUF);
}
/*===========================================================================*
* do_lstat *
*===========================================================================*/
PUBLIC int do_lstat()
{
/* Perform the lstat(name, buf) system call. */
struct vnode *vp;
int r;
if (fetch_name(m_in.name1, m_in.name1_length, M1) != OK) return(err_code);
if ((vp = eat_path(PATH_RET_SYMLINK, fp)) == NULL) return(err_code);
r = req_stat(vp->v_fs_e, vp->v_inode_nr, who_e, m_in.name2, 0);
put_vnode(vp);
return(r);
}