minix/servers/vfs/link.c

376 lines
9.2 KiB
C

/* This file handles the LINK and UNLINK system calls. It also deals with
* deallocating the storage used by a file when the last UNLINK is done to a
* file and the blocks must be returned to the free block pool.
*
* The entry points into this file are
* do_link: perform the LINK system call
* do_unlink: perform the UNLINK and RMDIR system calls
* do_rename: perform the RENAME system call
* do_truncate: perform the TRUNCATE system call
* do_ftruncate: perform the FTRUNCATE system call
* do_rdlink: perform the RDLNK system call
*
* Changes for VFS:
* Jul 2006 (Balazs Gerofi)
*/
#include "fs.h"
#include <sys/stat.h>
#include <string.h>
#include <minix/com.h>
#include <minix/callnr.h>
#include <dirent.h>
#include "file.h"
#include "fproc.h"
#include "param.h"
#include <minix/vfsif.h>
#include "vnode.h"
/*===========================================================================*
* do_link *
*===========================================================================*/
PUBLIC int do_link()
{
/* Perform the link(name1, name2) system call. */
int r;
endpoint_t linked_fs_e, link_lastdir_fs_e;
struct vnode *vp_o, *vp_d;
if (fetch_name(m_in.name1, m_in.name1_length, M1) != OK)
return(err_code);
/* Request lookup */
if ((r = lookup_vp(0 /*flags*/, 0 /*!use_realuid*/, &vp_o)) != OK) return r;
linked_fs_e = vp_o->v_fs_e;
/* Does the final directory of 'name2' exist? */
if (fetch_name(m_in.name2, m_in.name2_length, M1) != OK) {
put_vnode(vp_o);
return(err_code);
}
/* Request lookup */
if ((r = lookup_lastdir(0 /*!use_realuid*/, &vp_d)) != OK)
{
put_vnode(vp_o);
return r;
}
link_lastdir_fs_e = vp_d->v_fs_e;
/* Check for links across devices. */
if (linked_fs_e != link_lastdir_fs_e)
{
put_vnode(vp_o);
put_vnode(vp_d);
return EXDEV;
}
/* Make sure that the object is a directory */
if ((vp_d->v_mode & I_TYPE) != I_DIRECTORY)
{
put_vnode(vp_o);
put_vnode(vp_d);
return ENOTDIR;
}
r= forbidden(vp_d, W_BIT|X_BIT, 0 /*!use_realuid*/);
if (r != OK)
{
put_vnode(vp_o);
put_vnode(vp_d);
return r;
}
/* Issue request */
r= req_link(linked_fs_e, vp_d->v_inode_nr, user_fullpath, vp_o->v_inode_nr);
put_vnode(vp_o);
put_vnode(vp_d);
return r;
}
/*===========================================================================*
* do_unlink *
*===========================================================================*/
PUBLIC int do_unlink()
{
/* Perform the unlink(name) or rmdir(name) system call. The code for these two
* is almost the same. They differ only in some condition testing. Unlink()
* may be used by the superuser to do dangerous things; rmdir() may not.
*/
register struct fproc *rfp;
struct vnode *vp;
int r;
if (fetch_name(m_in.name, m_in.name_length, M3) != OK) return(err_code);
r= lookup_lastdir(0 /*!use_realuid*/, &vp);
if (r != OK)
return r;
/* Make sure that the object is a directory */
if ((vp->v_mode & I_TYPE) != I_DIRECTORY)
{
put_vnode(vp);
return ENOTDIR;
}
/* The caller must have both search and execute permission */
r= forbidden(vp, X_BIT|W_BIT, 0 /*!use_realuid*/);
if (r != OK)
{
put_vnode(vp);
return r;
}
/* If a directory file has to be removed the following conditions have to met:
* - The directory must not be the root of a mounted file system
* - The directory must not be anybody's root/working directory
*/
/* Issue request */
r= ((call_nr == UNLINK) ? req_unlink : req_rmdir)(vp->v_fs_e,
vp->v_inode_nr, user_fullpath);
put_vnode(vp);
return r;
}
/*===========================================================================*
* do_rename *
*===========================================================================*/
PUBLIC int do_rename()
{
/* Perform the rename(name1, name2) system call. */
int r;
int old_dir_inode;
int old_fs_e;
int new_dir_inode;
int new_fs_e;
size_t len;
struct vnode *vp_od, *vp_nd;
char old_name[PATH_MAX+1];
/* See if 'name1' (existing file) exists. Get dir and file inodes. */
if (fetch_name(m_in.name1, m_in.name1_length, M1) != OK) return(err_code);
/* Request lookup */
if ((r = lookup_lastdir(0 /*!use_realuid*/, &vp_od)) != OK) return r;
r= forbidden(vp_od, W_BIT|X_BIT, 0 /*!use_realuid*/);
if (r != OK)
{
put_vnode(vp_od);
return r;
}
/* Remeber FS endpoint */
old_fs_e = vp_od->v_fs_e;
/* Save the last component of the old name */
len= strlen(user_fullpath);
if (len >= sizeof(old_name))
{
put_vnode(vp_od);
return ENAMETOOLONG;
}
memcpy(old_name, user_fullpath, len+1);
/* See if 'name2' (new name) exists. Get dir inode */
if (fetch_name(m_in.name2, m_in.name2_length, M1) != OK)
{
put_vnode(vp_od);
return err_code;
}
/* Request lookup */
r = lookup_lastdir(0 /*!use_realuid*/, &vp_nd);
if (r != OK)
{
put_vnode(vp_od);
return r;
}
r= forbidden(vp_nd, W_BIT|X_BIT, 0 /*!use_realuid*/);
if (r != OK)
{
put_vnode(vp_od);
put_vnode(vp_nd);
return r;
}
/* Remeber FS endpoint */
new_fs_e = vp_nd->v_fs_e;
/* Both parent directories must be on the same device. */
if (old_fs_e != new_fs_e)
{
put_vnode(vp_od);
put_vnode(vp_nd);
return EXDEV;
}
/* Issue request */
r= req_rename(old_fs_e, vp_od->v_inode_nr, old_name, vp_nd->v_inode_nr,
user_fullpath);
put_vnode(vp_od);
put_vnode(vp_nd);
return r;
}
/*===========================================================================*
* do_truncate *
*===========================================================================*/
PUBLIC int do_truncate()
{
/* truncate_inode() does the actual work of do_truncate() and do_ftruncate().
* do_truncate() and do_ftruncate() have to get hold of the inode, either
* by name or fd, do checks on it, and call truncate_inode() to do the
* work.
*/
struct vnode *vp;
int r;
printf("in do_truncate\n");
if (fetch_name(m_in.m2_p1, m_in.m2_i1, M1) != OK) return err_code;
/* Request lookup */
if ((r = lookup_vp(0 /*flags*/, 0 /*!use_realuid*/, &vp)) != OK) return r;
if ((r = forbidden(vp, W_BIT, 0 /*!use_realuid*/)) == OK)
r = truncate_vn(vp, m_in.m2_l1);
put_vnode(vp);
return r;
}
/*===========================================================================*
* do_ftruncate *
*===========================================================================*/
PUBLIC int do_ftruncate()
{
/* As with do_truncate(), truncate_inode() does the actual work. */
int r;
struct filp *rfilp;
if ( (rfilp = get_filp(m_in.m2_i1)) == NIL_FILP)
return err_code;
if (!(rfilp->filp_mode & W_BIT))
return EBADF;
return truncate_vn(rfilp->filp_vno, m_in.m2_l1);
}
/*===========================================================================*
* truncate_vn *
*===========================================================================*/
PUBLIC int truncate_vn(vp, newsize)
struct vnode *vp;
off_t newsize;
{
int r;
if ( (vp->v_mode & I_TYPE) != I_REGULAR &&
(vp->v_mode & I_TYPE) != I_NAMED_PIPE) {
return EINVAL;
}
/* Issue request */
if ((r = req_ftrunc(vp->v_fs_e, vp->v_inode_nr, newsize, 0)) != OK) return r;
vp->v_size = newsize;
return OK;
}
/*===========================================================================*
* do_slink *
*===========================================================================*/
PUBLIC int do_slink()
{
/* Perform the symlink(name1, name2) system call. */
int r;
struct vnode *vp;
char string[NAME_MAX]; /* last component of the new dir's path name */
if (fetch_name(m_in.name2, m_in.name2_length, M1) != OK)
return(err_code);
if (m_in.name1_length <= 1 || m_in.name1_length >= _MIN_BLOCK_SIZE)
return(ENAMETOOLONG);
/* Request lookup */
if ((r = lookup_lastdir(0 /*!use_realuid*/, &vp)) != OK)
{
printf("vfs:do_slink: lookup_lastdir failed with %d\n", r);
return r;
}
#if 0
printf("vfs:do_slink: got dir inode %d on dev 0x%x, fs %d\n",
vp->v_inode_nr, vp->v_dev, vp->v_fs_e);
#endif
r= forbidden(vp, W_BIT|X_BIT, 0 /*!use_realuid*/);
if (r != OK)
{
put_vnode(vp);
return r;
}
/* Issue request */
r= req_slink(vp->v_fs_e, vp->v_inode_nr, user_fullpath, who_e, m_in.name1,
m_in.name1_length - 1, fp->fp_effuid, fp->fp_effgid);
put_vnode(vp);
return r;
}
/*===========================================================================*
* do_rdlink *
*===========================================================================*/
PUBLIC int do_rdlink()
{
/* Perform the readlink(name, buf) system call. */
int r, copylen;
struct vnode *vp;
copylen = m_in.m1_i2;
if(copylen < 0) return EINVAL;
if (fetch_name(m_in.name1, m_in.name1_length, M1) != OK) return(err_code);
/* Request lookup */
r = lookup_vp(PATH_RET_SYMLINK, 0 /*!use_realuid*/, &vp);
if (r != OK) return r;
/* Make sure this is a symbolic link */
if ((vp->v_mode & I_TYPE) != I_SYMBOLIC_LINK) {
put_vnode(vp);
return EINVAL;
}
/* Issue request */
r= req_rdlink(vp->v_fs_e, vp->v_inode_nr, who_e, (vir_bytes)m_in.name2,
copylen);
put_vnode(vp);
return r;
}