minix/servers/vfs/link.c
2007-01-05 16:36:55 +00:00

429 lines
12 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 linked_fs_e;
int linked_inode_nr;
int link_lastdir_fs_e;
int link_lastdir_inode_nr;
char string[NAME_MAX];
struct link_req req;
struct lookup_req lookup_req;
struct node_details res;
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;
linked_fs_e = res.fs_e;
req.linked_file = res.inode_nr;
/* Does the final directory of 'name2' exist? */
if (fetch_name(m_in.name2, m_in.name2_length, M1) != OK) {
return(err_code);
}
/* Fill in lookup request fields */
lookup_req.path = user_fullpath;
lookup_req.lastc = string;
lookup_req.flags = LAST_DIR;
/* Request lookup */
if ((r = lookup(&lookup_req, &res)) != OK) return r;
link_lastdir_fs_e = res.fs_e;
req.link_parent = res.inode_nr;
/* Check for links across devices. */
if (linked_fs_e != link_lastdir_fs_e)
return EXDEV;
/* Send link request. */
req.fs_e = linked_fs_e;
/* Send the last component of the link name */
req.uid = fp->fp_effuid;
req.gid = fp->fp_effgid;
req.lastc = string;
/* Issue request */
return req_link(&req);
}
/*===========================================================================*
* 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;
char string[NAME_MAX];
struct vnode *vp;
struct unlink_req req;
struct lookup_req lookup_req;
struct node_details res;
int r;
string[0] = '\0';
if (fetch_name(m_in.name, m_in.name_length, M3) != 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;
/* 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
*/
if ((res.fmode & I_TYPE) == I_DIRECTORY) {
/* Only root can unlink a directory */
if (call_nr == UNLINK && !super_user) return EPERM;
/* Can't remove a root directory */
if (res.inode_nr == ROOT_INODE) return EBUSY;
/* Can't remove anybody's working directory */
if ((vp = find_vnode(res.fs_e, res.inode_nr)) !=
NIL_VNODE) {
/* Check directories */
for (rfp = &fproc[INIT_PROC_NR + 1]; rfp < &fproc[NR_PROCS];
rfp++) {
if (rfp->fp_pid != PID_FREE &&
(rfp->fp_wd == vp || rfp->fp_rd == vp))
return(EBUSY);
}
}
}
/* Fill in lookup request fields */
lookup_req.path = user_fullpath;
lookup_req.lastc = string;
lookup_req.flags = LAST_DIR;
/* Request lookup */
if ((r = lookup(&lookup_req, &res)) != OK) return r;
/* Fill in request fields. */
req.fs_e = res.fs_e;
req.d_inode_nr = res.inode_nr;
req.uid = fp->fp_effuid;
req.gid = fp->fp_effgid;
req.lastc = string;
/* Issue request */
return (call_nr == UNLINK) ? req_unlink(&req) : req_rmdir(&req);
}
/*===========================================================================*
* do_rename *
*===========================================================================*/
PUBLIC int do_rename()
{
/* Perform the rename(name1, name2) system call. */
int old_dir_inode;
int old_fs_e;
int new_dir_inode;
int new_fs_e;
char old_name[NAME_MAX];
char new_name[NAME_MAX];
struct vnode *vp;
struct fproc *rfp;
struct rename_req req;
struct lookup_req lookup_req;
struct node_details res;
int r;
/* 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);
/* Fill in lookup request fields */
lookup_req.path = user_fullpath;
lookup_req.lastc = old_name;
lookup_req.flags = LAST_DIR;
/* Request lookup */
if ((r = lookup(&lookup_req, &res)) != OK) return r;
/* Remeber inode number and FS endpoint */
old_fs_e = res.fs_e;
req.old_dir = res.inode_nr;
/* See if 'name2' (new name) exists. Get dir inode */
if (fetch_name(m_in.name2, m_in.name2_length, M1) != OK) r = err_code;
/* Fill in lookup request fields */
lookup_req.path = user_fullpath;
lookup_req.lastc = NULL;
lookup_req.flags = EAT_PATH_OPAQUE;
/* Request lookup */
r = lookup(&lookup_req, &res);
/* 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
*/
if (r == OK && ((res.fmode & I_TYPE) == I_DIRECTORY)) {
/* Can't remove a root directory */
if (res.inode_nr == ROOT_INODE) return EBUSY;
/* Can't remove anybody's working directory */
if ((vp = find_vnode(res.fs_e, res.inode_nr)) !=
NIL_VNODE) {
/* Check directories */
for (rfp = &fproc[INIT_PROC_NR + 1]; rfp < &fproc[NR_PROCS];
rfp++) {
if (rfp->fp_pid != PID_FREE &&
(rfp->fp_wd == vp || rfp->fp_rd == vp))
return(EBUSY);
}
}
}
/* Fill in lookup request fields */
lookup_req.path = user_fullpath;
lookup_req.lastc = new_name;
lookup_req.flags = LAST_DIR;
/* Request lookup */
if ((r = lookup(&lookup_req, &res)) != OK) return r;
/* Remeber inode number and FS endpoint */
new_fs_e = res.fs_e;
req.new_dir = res.inode_nr;
/* Both parent directories must be on the same device. */
if (old_fs_e != new_fs_e) return EXDEV;
/* Send actual rename request */
req.fs_e = old_fs_e;
req.uid = fp->fp_effuid;
req.gid = fp->fp_effgid;
req.old_name = &old_name[0];
req.new_name = &new_name[0];
/* Issue request */
return req_rename(&req);
}
/*===========================================================================*
* 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;
struct trunc_req req;
struct lookup_req lookup_req;
struct node_details res;
int r;
printf("in do_truncate\n");
if (fetch_name(m_in.m2_p1, m_in.m2_i1, 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;
/* Check whether the file is in use or not */
vp = find_vnode(res.fs_e, res.inode_nr);
/* Fill in request message fields.*/
req.fs_e = res.fs_e;
req.length = m_in.m2_l1;
req.inode_nr = res.inode_nr;
req.uid = fp->fp_effuid;
req.gid = fp->fp_effgid;
/* Issue request */
if ((r = req_trunc(&req)) != OK) return r;
/* Change vnode's size if found */
if (vp != NIL_VNODE)
vp->v_size = m_in.m2_l1;
return OK;
}
/*===========================================================================*
* do_ftruncate *
*===========================================================================*/
PUBLIC int do_ftruncate()
{
/* As with do_truncate(), truncate_inode() does the actual work. */
struct filp *rfilp;
if ( (rfilp = get_filp(m_in.m2_i1)) == NIL_FILP)
return err_code;
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;
struct ftrunc_req req;
if ( (vp->v_mode & I_TYPE) != I_REGULAR &&
(vp->v_mode & I_TYPE) != I_NAMED_PIPE) {
return EINVAL;
}
/* Fill in FS request */
req.fs_e = vp->v_fs_e;
req.inode_nr = vp->v_inode_nr;
req.start = newsize;
req.end = 0; /* Indicate trunc in fs_freesp_trunc */
/* Issue request */
if ((r = req_ftrunc(&req)) != OK) return r;
vp->v_size = newsize;
return OK;
}
/*===========================================================================*
* do_slink *
*===========================================================================*/
PUBLIC int do_slink()
{
/* Perform the symlink(name1, name2) system call. */
char string[NAME_MAX]; /* last component of the new dir's path name */
struct slink_req req;
struct lookup_req lookup_req;
struct node_details res;
int r;
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);
/* Fill in lookup request fields */
lookup_req.path = user_fullpath;
lookup_req.lastc = string;
lookup_req.flags = LAST_DIR;
/* Request lookup */
if ((r = lookup(&lookup_req, &res)) != OK) return r;
/* Fill in request message */
req.fs_e = res.fs_e;
req.parent_dir = res.inode_nr;
req.uid = fp->fp_effuid;
req.gid = fp->fp_effgid;
req.lastc = string;
req.who_e = who_e;
req.path_addr = m_in.name1;
req.path_length = m_in.name1_length - 1;
/* Issue request */
return req_slink(&req);
}
/*===========================================================================*
* do_rdlink *
*===========================================================================*/
PUBLIC int do_rdlink()
{
/* Perform the readlink(name, buf) system call. */
int copylen;
struct rdlink_req req;
struct lookup_req lookup_req;
struct node_details res;
int r;
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);
/* 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 */
req.fs_e = res.fs_e;
req.inode_nr = res.inode_nr;
req.uid = fp->fp_effuid;
req.gid = fp->fp_effgid;
req.who_e = who_e;
req.path_buffer = m_in.name2;
req.max_length = copylen;
/* Issue request */
return req_rdlink(&req);
}