minix/servers/vfs/stadir.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_stat:	perform the STAT system call
 *   do_fstat:	perform the FSTAT system call
 *   do_fstatfs: perform the FSTATFS system call
 *   do_lstat:  perform the LSTAT system call
 *
 * Changes for VFS:
 *   Jul 2006 (Balazs Gerofi)
 */

#include "fs.h"
#include <sys/stat.h>
#include <sys/statfs.h>
#include <minix/com.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;
  struct getdir_req req;
  struct node_details res;
  int r;

  /* Is the file descriptor valid? */
  if ( (rfilp = get_filp(m_in.fd)) == NIL_FILP) return(err_code);

  /* Is it a dir? */
  if ((rfilp->filp_vno->v_mode & I_TYPE) != I_DIRECTORY)
      return ENOTDIR;
  
  /* Fill in request message fields.*/
  req.fs_e = rfilp->filp_vno->v_fs_e;
  req.inode_nr = rfilp->filp_vno->v_inode_nr;
  req.uid = fp->fp_effuid;
  req.gid = fp->fp_effgid;
  
  /* Issue request and handle error */
  if ((r = req_getdir(&req, &res)) != OK) return r;
  
  /* GETDIR increased the counter in the FS proc */
  rfilp->filp_vno->v_count++;
  
  return change_into(&fp->fp_wd, rfilp->filp_vno);
}

/*===========================================================================*
 *				do_chdir				     *
 *===========================================================================*/
PUBLIC int do_chdir()
{
/* Change directory.  This function is  also called by MM to simulate a chdir
 * in order to do EXEC, etc.  It also changes the root directory, the uids and
 * gids, and the umask. 
 */
  int r;
  register struct fproc *rfp;

  if (who_e == PM_PROC_NR) {
	int slot;
	if(isokendpt(m_in.endpt1, &slot) != OK)
		return EINVAL;
	rfp = &fproc[slot];
        
        put_vnode(fp->fp_rd);
        dup_vnode(fp->fp_rd = rfp->fp_rd);
        put_vnode(fp->fp_wd);
        dup_vnode(fp->fp_wd = rfp->fp_wd);
        
	/* MM uses access() to check permissions.  To make this work, pretend
	 * that the user's real ids are the same as the user's effective ids.
	 * FS calls other than access() do not use the real ids, so are not
	 * affected.
	 */
	fp->fp_realuid =
	fp->fp_effuid = rfp->fp_effuid;
	fp->fp_realgid =
	fp->fp_effgid = rfp->fp_effgid;
	fp->fp_umask = rfp->fp_umask;
	return(OK);
  }

  /* Perform the chdir(name) system call. */
  r = change(&fp->fp_wd, m_in.name, m_in.name_length);
  return(r);
}

/*===========================================================================*
 *				do_chroot				     *
 *===========================================================================*/
PUBLIC int do_chroot()
{
/* Perform the chroot(name) system call. */

  register int r;

  if (!super_user) return(EPERM);	/* only su may chroot() */
  
  r = change(&fp->fp_rd, m_in.name, m_in.name_length);
  return(r);
}


/*===========================================================================*
 *				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, *vp2;
  struct vmnt *vmp;
  struct getdir_req req;
  struct node_details res;
  struct lookup_req lookup_req;
  int r;

  if (fetch_name(name_ptr, len, M3) != OK) return(err_code);
  
  /* See if free vnode is available */
  if ((vp = get_free_vnode()) == NIL_VNODE) {
      printf("VFSchange: no free vnode available\n");
      return EINVAL;
  }

  /* Fill in lookup request fields */
  lookup_req.path = user_fullpath;
  lookup_req.lastc = NULL;
  lookup_req.flags = EAT_PATH;
        
  /* Request lookup */
  if ((r = lookup(&lookup_req, &res)) != OK) return r;

  /* Is it a dir? */
  if ((res.fmode & I_TYPE) != I_DIRECTORY)
      return ENOTDIR;
  
  /* Fill in request message fields.*/
  req.fs_e = res.fs_e;
  req.inode_nr = res.inode_nr;
  req.uid = fp->fp_effuid;
  req.gid = fp->fp_effgid;
 
  /* Issue request */
  if ((r = req_getdir(&req, &res)) != OK) return r;
  
  /* Check whether vnode is already in use or not */
  if ((vp2 = find_vnode(res.fs_e, res.inode_nr)) 
          != NIL_VNODE) {
        vp2->v_count++;
        vp = vp2;
  }
  else {
        /* Fill in the free vnode's fields */
        vp->v_fs_e = res.fs_e;
        vp->v_inode_nr = res.inode_nr;
        vp->v_mode = res.fmode;
        vp->v_size = res.fsize;

          if ( (vmp = find_vmnt(vp->v_fs_e)) == NIL_VMNT)
              printf("VFSchange: vmnt not found");

        vp->v_vmnt = vmp; 
        vp->v_dev = vmp->m_dev;
        vp->v_count = 1;
  }

  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 */
{
  /* 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. */
  struct stat_req req;
  struct node_details res;
  struct lookup_req lookup_req;
  int r;
    
  if (fetch_name(m_in.name1, m_in.name1_length, M1) != OK) return(err_code);
  
  /* Fill in lookup request fields */
  lookup_req.path = user_fullpath;
  lookup_req.lastc = NULL;
  lookup_req.flags = EAT_PATH;
        
  /* Request lookup */
  if ((r = lookup(&lookup_req, &res)) != OK) return r;

  /* Fill in request message fields.*/
  req.fs_e = res.fs_e;
  req.who_e = who_e;
  req.buf = m_in.name2;
  req.inode_nr = res.inode_nr;
  req.uid = fp->fp_effuid;
  req.gid = fp->fp_effgid;
  
  /* Issue request */
  return req_stat(&req);
}



/*===========================================================================*
 *				do_fstat				     *
 *===========================================================================*/
PUBLIC int do_fstat()
{
/* Perform the fstat(fd, buf) system call. */
  register struct filp *rfilp;
  int pipe_pos = 0;
  struct stat_req req;

  /* Is the file descriptor valid? */
  if ( (rfilp = get_filp(m_in.fd)) == NIL_FILP) {
	  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) 
		pipe_pos = rfilp->filp_pos;
  }

  /* Fill in request message */
  req.fs_e = rfilp->filp_vno->v_fs_e;
  req.inode_nr = rfilp->filp_vno->v_inode_nr;
  req.pos = pipe_pos;
  req.who_e = who_e;
  req.buf = m_in.buffer;

  /* Issue request */
  return req_fstat(&req);
}



/*===========================================================================*
 *				do_fstatfs				     *
 *===========================================================================*/
PUBLIC int do_fstatfs()
{
  /* Perform the fstatfs(fd, buf) system call. */
  register struct filp *rfilp;
  struct stat_req req;

  /* Is the file descriptor valid? */
  if ( (rfilp = get_filp(m_in.fd)) == NIL_FILP) return(err_code);

  /* Send FS request */
  req.fs_e = rfilp->filp_vno->v_fs_e;
  req.inode_nr = rfilp->filp_vno->v_inode_nr;
  req.who_e = who_e;
  req.buf = m_in.buffer;
  
  /* Issue request */
  return req_fstatfs(&req);
}



/*===========================================================================*
 *                             do_lstat                                      *
 *===========================================================================*/
PUBLIC int do_lstat()
{
/* Perform the lstat(name, buf) system call. */
  struct stat_req req;
  struct node_details res;
  struct lookup_req lookup_req;
  int r;

  if (fetch_name(m_in.name1, m_in.name1_length, M1) != OK) return(err_code);
  
  /* Fill in lookup request fields */
  lookup_req.path = user_fullpath;
  lookup_req.lastc = NULL;
  lookup_req.flags = EAT_PATH_OPAQUE;
        
  /* Request lookup */
  if ((r = lookup(&lookup_req, &res)) != OK) return r;

  /* Fill in request message fields.*/
  req.fs_e = res.fs_e;
  req.who_e = who_e;
  req.buf = m_in.name2;
  req.inode_nr = res.inode_nr;
  req.uid = fp->fp_effuid;
  req.gid = fp->fp_effgid;
  
  /* Issue request */
  return req_stat(&req);
}