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minix/servers/mfs/link.c
Ben Gras a38287067a disable scary looking debug messages.
2009-05-07 09:58:16 +00:00

1188 lines
36 KiB
C
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#include "fs.h"
#include <sys/stat.h>
#include <string.h>
#include <minix/com.h>
#include <minix/callnr.h>
#include "buf.h"
#include "inode.h"
#include "super.h"
#include <minix/vfsif.h>
#define SAME 1000
FORWARD _PROTOTYPE( int remove_dir_o, (struct inode *rldirp, struct inode *rip,
char dir_name[NAME_MAX]) );
FORWARD _PROTOTYPE( int remove_dir_nocheck, (struct inode *rldirp,
struct inode *rip, char dir_name[NAME_MAX]) );
FORWARD _PROTOTYPE( int unlink_file_o, (struct inode *dirp, struct inode *rip,
char file_name[NAME_MAX]) );
FORWARD _PROTOTYPE( int unlink_file_nocheck, (struct inode *dirp,
struct inode *rip, char file_name[NAME_MAX]) );
FORWARD _PROTOTYPE( off_t nextblock, (off_t pos, int zonesize) );
FORWARD _PROTOTYPE( void zeroblock_half, (struct inode *i, off_t p, int l));
FORWARD _PROTOTYPE( void zeroblock_range, (struct inode *i, off_t p, off_t h));
/* Args to zeroblock_half() */
#define FIRST_HALF 0
#define LAST_HALF 1
/*===========================================================================*
* fs_link_o *
*===========================================================================*/
PUBLIC int fs_link_o()
{
/* Perform the link(name1, name2) system call. */
struct inode *ip, *rip;
register int r;
char string[NAME_MAX];
struct inode *new_ip;
phys_bytes len;
caller_uid = fs_m_in.REQ_UID;
caller_gid = fs_m_in.REQ_GID;
len = MFS_MIN(fs_m_in.REQ_PATH_LEN, sizeof(string));
/* Copy the link name's last component */
r = sys_datacopy(FS_PROC_NR, (vir_bytes) fs_m_in.REQ_PATH,
SELF, (vir_bytes) string, (phys_bytes) len);
if (r != OK) return r;
MFS_NUL(string, len, sizeof(string));
/* Temporarily open the file. */
if ( (rip = get_inode(fs_dev, fs_m_in.REQ_LINKED_FILE)) == NIL_INODE) {
printf("MFS(%d) get_inode by fs_link() failed\n", SELF_E);
return(EINVAL);
}
/* Check to see if the file has maximum number of links already. */
r = OK;
if (rip->i_nlinks >= (rip->i_sp->s_version == V1 ? CHAR_MAX : SHRT_MAX))
r = EMLINK;
/* Only super_user may link to directories. */
if (r == OK)
if ( (rip->i_mode & I_TYPE) == I_DIRECTORY && caller_uid != SU_UID)
r = EPERM;
/* If error with 'name', return the inode. */
if (r != OK) {
put_inode(rip);
return(r);
}
/* Temporarily open the last dir */
if ( (ip = get_inode(fs_dev, fs_m_in.REQ_LINK_PARENT)) == NIL_INODE) {
printf("MFS(%d) get_inode by fs_link() failed\n", SELF_E);
return(EINVAL);
}
/* If 'name2' exists in full (even if no space) set 'r' to error. */
if (r == OK) {
if ( (new_ip = advance_o(&ip, string)) == NIL_INODE) {
r = err_code;
if (r == ENOENT) r = OK;
} else {
put_inode(new_ip);
r = EEXIST;
}
}
/* Try to link. */
if (r == OK)
r = search_dir(ip, string, &rip->i_num, ENTER);
/* If success, register the linking. */
if (r == OK) {
rip->i_nlinks++;
rip->i_update |= CTIME;
rip->i_dirt = DIRTY;
}
/* Done. Release both inodes. */
put_inode(rip);
put_inode(ip);
return(r);
}
/*===========================================================================*
* fs_link_s *
*===========================================================================*/
PUBLIC int fs_link_s()
{
/* Perform the link(name1, name2) system call. */
struct inode *ip, *rip;
register int r;
char string[NAME_MAX];
struct inode *new_ip;
phys_bytes len;
#if 0
caller_uid = fs_m_in.REQ_UID;
caller_gid = fs_m_in.REQ_GID;
#endif
len = MFS_MIN(fs_m_in.REQ_PATH_LEN, sizeof(string));
/* Copy the link name's last component */
r = sys_safecopyfrom(FS_PROC_NR, fs_m_in.REQ_GRANT, 0,
(vir_bytes) string, (phys_bytes) len, D);
if (r != OK) return r;
MFS_NUL(string, len, sizeof(string));
/* Temporarily open the file. */
if ( (rip = get_inode(fs_dev, fs_m_in.REQ_LINKED_FILE)) == NIL_INODE) {
printf("MFS(%d) get_inode by fs_link() failed\n", SELF_E);
return(EINVAL);
}
/* Check to see if the file has maximum number of links already. */
r = OK;
if (rip->i_nlinks >= (rip->i_sp->s_version == V1 ? CHAR_MAX : SHRT_MAX))
r = EMLINK;
/* Only super_user may link to directories. */
if (r == OK)
if ( (rip->i_mode & I_TYPE) == I_DIRECTORY && caller_uid != SU_UID)
r = EPERM;
/* If error with 'name', return the inode. */
if (r != OK) {
put_inode(rip);
return(r);
}
/* Temporarily open the last dir */
if ( (ip = get_inode(fs_dev, fs_m_in.REQ_LINK_PARENT)) == NIL_INODE) {
printf("MFS(%d) get_inode by fs_link() failed\n", SELF_E);
return(EINVAL);
}
/* If 'name2' exists in full (even if no space) set 'r' to error. */
if (r == OK) {
if ( (new_ip = advance_nocheck(&ip, string)) == NIL_INODE) {
r = err_code;
if (r == ENOENT) r = OK;
} else {
put_inode(new_ip);
r = EEXIST;
}
}
/* Try to link. */
if (r == OK)
r = search_dir_nocheck(ip, string, &rip->i_num, ENTER);
/* If success, register the linking. */
if (r == OK) {
rip->i_nlinks++;
rip->i_update |= CTIME;
rip->i_dirt = DIRTY;
}
/* Done. Release both inodes. */
put_inode(rip);
put_inode(ip);
return(r);
}
/*===========================================================================*
* fs_unlink_o *
*===========================================================================*/
PUBLIC int fs_unlink_o()
{
/* 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 inode *rip;
struct inode *rldirp;
int r;
char string[NAME_MAX];
phys_bytes len;
caller_uid = fs_m_in.REQ_UID;
caller_gid = fs_m_in.REQ_GID;
/* Copy the last component */
len = MFS_MIN(fs_m_in.REQ_PATH_LEN, sizeof(string));
r = sys_datacopy(FS_PROC_NR, (vir_bytes) fs_m_in.REQ_PATH,
SELF, (vir_bytes) string, (phys_bytes) len);
if (r != OK) return r;
MFS_NUL(string, len, sizeof(string));
/* Temporarily open the dir. */
if ( (rldirp = get_inode(fs_dev, fs_m_in.REQ_INODE_NR)) == NIL_INODE) {
return(EINVAL);
}
/* The last directory exists. Does the file also exist? */
r = OK;
if ( (rip = advance_o(&rldirp, string)) == NIL_INODE) r = err_code;
/* If error, return inode. */
if (r != OK) {
printf("fs_unlink_o: advance_o failed: %d\n", r);
/* Mount point? */
if (r == EENTERMOUNT || r == ELEAVEMOUNT)
r = EBUSY;
put_inode(rldirp);
return(r);
}
/* Now test if the call is allowed, separately for unlink() and rmdir(). */
if (fs_m_in.m_type == REQ_UNLINK_O) {
/* Only the su may unlink directories, but the su can unlink any dir.*/
if ( (rip->i_mode & I_TYPE) == I_DIRECTORY
&& caller_uid != SU_UID) r = EPERM;
/* Don't unlink a file if it is the root of a mounted file system. */
if (rip->i_num == ROOT_INODE) r = EBUSY;
/* Actually try to unlink the file; fails if parent is mode 0 etc. */
if (r == OK) r = unlink_file_o(rldirp, rip, string);
}
else {
r = remove_dir_o(rldirp, rip, string); /* call is RMDIR */
}
/* If unlink was possible, it has been done, otherwise it has not. */
put_inode(rip);
put_inode(rldirp);
if (r != OK) printf("fs_unlink_o: returning %d\n", r);
return(r);
}
/*===========================================================================*
* fs_unlink_s *
*===========================================================================*/
PUBLIC int fs_unlink_s()
{
/* 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 inode *rip;
struct inode *rldirp;
int r;
char string[NAME_MAX];
phys_bytes len;
/* Copy the last component */
len = MFS_MIN(fs_m_in.REQ_PATH_LEN, sizeof(string));
r = sys_safecopyfrom(FS_PROC_NR, fs_m_in.REQ_GRANT, 0,
(vir_bytes) string, (phys_bytes) len, D);
if (r != OK) return r;
MFS_NUL(string, len, sizeof(string));
/* Temporarily open the dir. */
if ( (rldirp = get_inode(fs_dev, fs_m_in.REQ_INODE_NR)) == NIL_INODE) {
return(EINVAL);
}
/* The last directory exists. Does the file also exist? */
r = OK;
if ( (rip = advance_nocheck(&rldirp, string)) == NIL_INODE) r = err_code;
/* If error, return inode. */
if (r != OK) {
/* Mount point? */
if (r == EENTERMOUNT || r == ELEAVEMOUNT)
r = EBUSY;
put_inode(rldirp);
return(r);
}
/* Now test if the call is allowed, separately for unlink() and rmdir(). */
if (fs_m_in.m_type == REQ_UNLINK_S) {
/* Only the su may unlink directories, but the su can unlink any dir.*/
if ( (rip->i_mode & I_TYPE) == I_DIRECTORY) r = EPERM;
/* Actually try to unlink the file; fails if parent is mode 0 etc. */
if (r == OK) r = unlink_file_nocheck(rldirp, rip, string);
}
else {
r = remove_dir_nocheck(rldirp, rip, string); /* call is RMDIR */
}
/* If unlink was possible, it has been done, otherwise it has not. */
put_inode(rip);
put_inode(rldirp);
return(r);
}
/*===========================================================================*
* fs_rdlink_o *
*===========================================================================*/
PUBLIC int fs_rdlink_o()
{
block_t b; /* block containing link text */
struct buf *bp; /* buffer containing link text */
register struct inode *rip; /* target inode */
register int r; /* return value */
int copylen;
copylen = fs_m_in.REQ_SLENGTH;
caller_uid = fs_m_in.REQ_UID;
caller_gid = fs_m_in.REQ_GID;
/* Temporarily open the file. */
if ( (rip = get_inode(fs_dev, fs_m_in.REQ_INODE_NR)) == NIL_INODE) {
return(EINVAL);
}
r = EACCES;
if (S_ISLNK(rip->i_mode) && (b = read_map(rip, (off_t) 0)) != NO_BLOCK) {
if (copylen <= 0) r = EINVAL;
else if (copylen < rip->i_size) r = ERANGE;
else {
if(rip->i_size < copylen) copylen = rip->i_size;
bp = get_block(rip->i_dev, b, NORMAL);
r = sys_vircopy(SELF, D, (vir_bytes) bp->b_data,
fs_m_in.REQ_WHO_E, D, (vir_bytes) fs_m_in.REQ_USER_ADDR,
(vir_bytes) copylen);
if (r == OK) r = copylen;
put_block(bp, DIRECTORY_BLOCK);
}
}
put_inode(rip);
return(r);
}
/*===========================================================================*
* fs_rdlink_s *
*===========================================================================*/
PUBLIC int fs_rdlink_s()
{
block_t b; /* block containing link text */
struct buf *bp; /* buffer containing link text */
register struct inode *rip; /* target inode */
register int r; /* return value */
int copylen;
copylen = fs_m_in.REQ_SLENGTH;
if (copylen <= 0) return(EINVAL);
/* Temporarily open the file. */
if ( (rip = get_inode(fs_dev, fs_m_in.REQ_INODE_NR)) == NIL_INODE) {
return(EINVAL);
}
if (!S_ISLNK(rip->i_mode))
r = EACCES;
else if (copylen < rip->i_size)
r = ERANGE;
else if ((b = read_map(rip, (off_t) 0)) == NO_BLOCK)
r = EIO;
else {
/* Passed all checks */
copylen = rip->i_size;
bp = get_block(rip->i_dev, b, NORMAL);
r = sys_safecopyto(FS_PROC_NR, fs_m_in.REQ_GRANT, 0,
(vir_bytes) bp->b_data, (vir_bytes) copylen, D);
put_block(bp, DIRECTORY_BLOCK);
if (r == OK) r = copylen;
}
put_inode(rip);
return(r);
}
/*===========================================================================*
* remove_dir_o *
*===========================================================================*/
PRIVATE int remove_dir_o(rldirp, rip, dir_name)
struct inode *rldirp; /* parent directory */
struct inode *rip; /* directory to be removed */
char dir_name[NAME_MAX]; /* name of directory to be removed */
{
/* A directory file has to be removed. Five conditions have to met:
* - The file must be a directory
* - The directory must be empty (except for . and ..)
* - The final component of the path must not be . or ..
* - The directory must not be the root of a mounted file system (VFS)
* - The directory must not be anybody's root/working directory (VFS)
*/
int r;
/* search_dir checks that rip is a directory too. */
if ((r = search_dir(rip, "", (ino_t *) 0, IS_EMPTY)) != OK) return r;
if (strcmp(dir_name, ".") == 0 || strcmp(dir_name, "..") == 0)return(EINVAL);
if (rip->i_num == ROOT_INODE) return(EBUSY); /* can't remove 'root' */
/* Actually try to unlink the file; fails if parent is mode 0 etc. */
if ((r = unlink_file_o(rldirp, rip, dir_name)) != OK) return r;
/* Unlink . and .. from the dir. The super user can link and unlink any dir,
* so don't make too many assumptions about them.
*/
(void) unlink_file_o(rip, NIL_INODE, dot1);
(void) unlink_file_o(rip, NIL_INODE, dot2);
return(OK);
}
/*===========================================================================*
* remove_dir_nocheck *
*===========================================================================*/
PRIVATE int remove_dir_nocheck(rldirp, rip, dir_name)
struct inode *rldirp; /* parent directory */
struct inode *rip; /* directory to be removed */
char dir_name[NAME_MAX]; /* name of directory to be removed */
{
/* A directory file has to be removed. Five conditions have to met:
* - The file must be a directory
* - The directory must be empty (except for . and ..)
* - The final component of the path must not be . or ..
* - The directory must not be the root of a mounted file system (VFS)
* - The directory must not be anybody's root/working directory (VFS)
*/
int r;
/* search_dir checks that rip is a directory too. */
if ((r = search_dir_nocheck(rip, "", (ino_t *) 0, IS_EMPTY)) != OK) return r;
if (strcmp(dir_name, ".") == 0 || strcmp(dir_name, "..") == 0)return(EINVAL);
if (rip->i_num == ROOT_INODE) return(EBUSY); /* can't remove 'root' */
/* Actually try to unlink the file; fails if parent is mode 0 etc. */
if ((r = unlink_file_nocheck(rldirp, rip, dir_name)) != OK) return r;
/* Unlink . and .. from the dir. The super user can link and unlink any dir,
* so don't make too many assumptions about them.
*/
(void) unlink_file_nocheck(rip, NIL_INODE, dot1);
(void) unlink_file_nocheck(rip, NIL_INODE, dot2);
return(OK);
}
/*===========================================================================*
* unlink_file_o *
*===========================================================================*/
PRIVATE int unlink_file_o(dirp, rip, file_name)
struct inode *dirp; /* parent directory of file */
struct inode *rip; /* inode of file, may be NIL_INODE too. */
char file_name[NAME_MAX]; /* name of file to be removed */
{
/* Unlink 'file_name'; rip must be the inode of 'file_name' or NIL_INODE. */
ino_t numb; /* inode number */
int r;
/* If rip is not NIL_INODE, it is used to get faster access to the inode. */
if (rip == NIL_INODE) {
/* Search for file in directory and try to get its inode. */
err_code = search_dir(dirp, file_name, &numb, LOOK_UP);
if (err_code == OK) rip = get_inode(dirp->i_dev, (int) numb);
if (err_code != OK || rip == NIL_INODE) return(err_code);
} else {
dup_inode(rip); /* inode will be returned with put_inode */
}
r = search_dir(dirp, file_name, (ino_t *) 0, DELETE);
if (r == OK) {
rip->i_nlinks--; /* entry deleted from parent's dir */
rip->i_update |= CTIME;
rip->i_dirt = DIRTY;
}
put_inode(rip);
return(r);
}
/*===========================================================================*
* unlink_file_nocheck *
*===========================================================================*/
PRIVATE int unlink_file_nocheck(dirp, rip, file_name)
struct inode *dirp; /* parent directory of file */
struct inode *rip; /* inode of file, may be NIL_INODE too. */
char file_name[NAME_MAX]; /* name of file to be removed */
{
/* Unlink 'file_name'; rip must be the inode of 'file_name' or NIL_INODE. */
ino_t numb; /* inode number */
int r;
/* If rip is not NIL_INODE, it is used to get faster access to the inode. */
if (rip == NIL_INODE) {
/* Search for file in directory and try to get its inode. */
err_code = search_dir_nocheck(dirp, file_name, &numb, LOOK_UP);
if (err_code == OK) rip = get_inode(dirp->i_dev, (int) numb);
if (err_code != OK || rip == NIL_INODE) return(err_code);
} else {
dup_inode(rip); /* inode will be returned with put_inode */
}
r = search_dir_nocheck(dirp, file_name, (ino_t *) 0, DELETE);
if (r == OK) {
rip->i_nlinks--; /* entry deleted from parent's dir */
rip->i_update |= CTIME;
rip->i_dirt = DIRTY;
}
put_inode(rip);
return(r);
}
/*===========================================================================*
* fs_rename_o *
*===========================================================================*/
PUBLIC int fs_rename_o()
{
/* Perform the rename(name1, name2) system call. */
struct inode *old_dirp, *old_ip; /* ptrs to old dir, file inodes */
struct inode *new_dirp, *new_ip; /* ptrs to new dir, file inodes */
struct inode *new_superdirp, *next_new_superdirp;
int r = OK; /* error flag; initially no error */
int odir, ndir; /* TRUE iff {old|new} file is dir */
int same_pdir; /* TRUE iff parent dirs are the same */
char old_name[NAME_MAX], new_name[NAME_MAX];
ino_t numb;
phys_bytes len;
int r1;
caller_uid = fs_m_in.REQ_UID;
caller_gid = fs_m_in.REQ_GID;
/* Copy the last component of the old name */
len = MFS_MIN(fs_m_in.REQ_PATH_LEN, sizeof(old_name));
r = sys_datacopy(FS_PROC_NR, (vir_bytes) fs_m_in.REQ_PATH,
SELF, (vir_bytes) old_name, (phys_bytes) len);
if (r != OK) return r;
MFS_NUL(old_name, len, sizeof(old_name));
/* Copy the last component of the new name */
len = MFS_MIN(fs_m_in.REQ_SLENGTH, sizeof(new_name));
r = sys_datacopy(FS_PROC_NR, (vir_bytes) fs_m_in.REQ_USER_ADDR,
SELF, (vir_bytes) new_name, (phys_bytes) len);
if (r != OK) return r;
MFS_NUL(new_name, len, sizeof(new_name));
/* Get old dir inode */
if ( (old_dirp = get_inode(fs_dev, fs_m_in.REQ_OLD_DIR)) == NIL_INODE)
return(err_code);
if ( (old_ip = advance_o(&old_dirp, old_name)) == NIL_INODE) r = err_code;
/* Get new dir inode */
if ( (new_dirp = get_inode(fs_dev, fs_m_in.REQ_NEW_DIR)) == NIL_INODE)
r = err_code;
new_ip = advance_o(&new_dirp, new_name); /* not required to exist */
if (old_ip != NIL_INODE)
odir = ((old_ip->i_mode & I_TYPE) == I_DIRECTORY); /* TRUE iff dir */
/* If it is ok, check for a variety of possible errors. */
if (r == OK) {
same_pdir = (old_dirp == new_dirp);
/* The old inode must not be a superdirectory of the new last dir. */
if (odir && !same_pdir) {
dup_inode(new_superdirp = new_dirp);
while (TRUE) { /* may hang in a file system loop */
if (new_superdirp == old_ip) {
put_inode(new_superdirp);
r = EINVAL;
break;
}
next_new_superdirp = advance_o(&new_superdirp, dot2);
put_inode(new_superdirp);
/*
if (next_new_superdirp == new_superdirp) {
put_inode(new_superdirp);
break;
}
*/
if (err_code == ELEAVEMOUNT) {
/* imitate that we are back at the root,
* cross device checked already on VFS */
/*next_new_superdirp = new_superdirp;*/
err_code = OK;
break;
}
new_superdirp = next_new_superdirp;
if (new_superdirp == NIL_INODE) {
/* Missing ".." entry. Assume the worst. */
r = EINVAL;
break;
}
}
/*put_inode(new_superdirp);*/
}
/* The old or new name must not be . or .. */
if (strcmp(old_name, ".")==0 || strcmp(old_name, "..")==0 ||
strcmp(new_name, ".")==0 || strcmp(new_name, "..")==0) {
r = EINVAL;
}
/* Both parent directories must be on the same device.
if (old_dirp->i_dev != new_dirp->i_dev) r = EXDEV; */
/* Parent dirs must be writable, searchable and on a writable device */
if ((r1 = forbidden(old_dirp, W_BIT | X_BIT)) != OK ||
(r1 = forbidden(new_dirp, W_BIT | X_BIT)) != OK) {
r = r1;
}
/* Some tests apply only if the new path exists. */
if (new_ip == NIL_INODE) {
/* don't rename a file with a file system mounted on it.
if (old_ip->i_dev != old_dirp->i_dev) r = EXDEV;*/
if (odir && new_dirp->i_nlinks >=
(new_dirp->i_sp->s_version == V1 ? CHAR_MAX : SHRT_MAX) &&
!same_pdir && r == OK) {
r = EMLINK;
}
}
else {
if (old_ip == new_ip) {
r = SAME; /* old=new */
}
/* has the old file or new file a file system mounted on it?
if (old_ip->i_dev != new_ip->i_dev) r = EXDEV;
*/
ndir = ((new_ip->i_mode & I_TYPE) == I_DIRECTORY); /* dir ? */
if (odir == TRUE && ndir == FALSE) {
r = ENOTDIR;
}
if (odir == FALSE && ndir == TRUE) {
r = EISDIR;
}
}
}
/* If a process has another root directory than the system root, we might
* "accidently" be moving it's working directory to a place where it's
* root directory isn't a super directory of it anymore. This can make
* the function chroot useless. If chroot will be used often we should
* probably check for it here.
*/
/* The rename will probably work. Only two things can go wrong now:
* 1. being unable to remove the new file. (when new file already exists)
* 2. being unable to make the new directory entry. (new file doesn't exists)
* [directory has to grow by one block and cannot because the disk
* is completely full].
*/
if (r == OK) {
if (new_ip != NIL_INODE) {
/* There is already an entry for 'new'. Try to remove it. */
if (odir)
r = remove_dir_o(new_dirp, new_ip, new_name);
else
r = unlink_file_o(new_dirp, new_ip, new_name);
}
/* if r is OK, the rename will succeed, while there is now an
* unused entry in the new parent directory.
*/
}
if (r == OK) {
/* If the new name will be in the same parent directory as the old one,
* first remove the old name to free an entry for the new name,
* otherwise first try to create the new name entry to make sure
* the rename will succeed.
*/
numb = old_ip->i_num; /* inode number of old file */
if (same_pdir) {
r = search_dir(old_dirp, old_name, (ino_t *) 0, DELETE);
/* shouldn't go wrong. */
if (r==OK) (void) search_dir(old_dirp, new_name, &numb, ENTER);
} else {
r = search_dir(new_dirp, new_name, &numb, ENTER);
if (r == OK)
(void) search_dir(old_dirp, old_name, (ino_t *) 0, DELETE);
}
}
/* If r is OK, the ctime and mtime of old_dirp and new_dirp have been marked
* for update in search_dir.
*/
if (r == OK && odir && !same_pdir) {
/* Update the .. entry in the directory (still points to old_dirp). */
numb = new_dirp->i_num;
(void) unlink_file_o(old_ip, NIL_INODE, dot2);
if (search_dir(old_ip, dot2, &numb, ENTER) == OK) {
/* New link created. */
new_dirp->i_nlinks++;
new_dirp->i_dirt = DIRTY;
}
}
/* Release the inodes. */
put_inode(old_dirp);
put_inode(old_ip);
put_inode(new_dirp);
put_inode(new_ip);
return(r == SAME ? OK : r);
}
/*===========================================================================*
* fs_rename_s *
*===========================================================================*/
PUBLIC int fs_rename_s()
{
/* Perform the rename(name1, name2) system call. */
struct inode *old_dirp, *old_ip; /* ptrs to old dir, file inodes */
struct inode *new_dirp, *new_ip; /* ptrs to new dir, file inodes */
struct inode *new_superdirp, *next_new_superdirp;
int r = OK; /* error flag; initially no error */
int odir, ndir; /* TRUE iff {old|new} file is dir */
int same_pdir; /* TRUE iff parent dirs are the same */
char old_name[NAME_MAX], new_name[NAME_MAX];
ino_t numb;
phys_bytes len;
int r1;
/* Copy the last component of the old name */
len = MFS_MIN(fs_m_in.REQ_REN_LEN_OLD, sizeof(old_name));
r = sys_safecopyfrom(FS_PROC_NR, fs_m_in.REQ_REN_GRANT_OLD, 0,
(vir_bytes) old_name, (phys_bytes) len, D);
if (r != OK) return r;
MFS_NUL(old_name, len, sizeof(old_name));
/* Copy the last component of the new name */
len = MFS_MIN(fs_m_in.REQ_REN_LEN_NEW, sizeof(new_name));
r = sys_safecopyfrom(FS_PROC_NR, fs_m_in.REQ_REN_GRANT_NEW, 0,
(vir_bytes) new_name, (phys_bytes) len, D);
if (r != OK) return r;
MFS_NUL(new_name, len, sizeof(new_name));
/* Get old dir inode */
if ( (old_dirp = get_inode(fs_dev, fs_m_in.REQ_REN_OLD_DIR)) == NIL_INODE)
return(err_code);
if ( (old_ip = advance_nocheck(&old_dirp, old_name)) == NIL_INODE)
r = err_code;
/* Get new dir inode */
if ( (new_dirp = get_inode(fs_dev, fs_m_in.REQ_REN_NEW_DIR)) == NIL_INODE)
r = err_code;
new_ip = advance_nocheck(&new_dirp, new_name); /* not required to exist */
if (old_ip != NIL_INODE)
odir = ((old_ip->i_mode & I_TYPE) == I_DIRECTORY); /* TRUE iff dir */
/* If it is ok, check for a variety of possible errors. */
if (r == OK) {
same_pdir = (old_dirp == new_dirp);
/* The old inode must not be a superdirectory of the new last dir. */
if (odir && !same_pdir) {
dup_inode(new_superdirp = new_dirp);
while (TRUE) { /* may hang in a file system loop */
if (new_superdirp == old_ip) {
put_inode(new_superdirp);
r = EINVAL;
break;
}
#if 0
printf("fs_rename_s: new_superdirp: %d on 0x%x\n",
new_superdirp->i_num, new_superdirp->i_dev);
#endif
next_new_superdirp = advance_nocheck(&new_superdirp,
dot2);
#if 0
printf("fs_rename_s: next_new_superdirp: %d on 0x%x\n",
next_new_superdirp->i_num, next_new_superdirp->i_dev);
#endif
put_inode(new_superdirp);
if (next_new_superdirp == new_superdirp) {
put_inode(new_superdirp);
break;
}
if (err_code == ELEAVEMOUNT) {
/* imitate that we are back at the root,
* cross device checked already on VFS */
/*next_new_superdirp = new_superdirp;*/
err_code = OK;
break;
}
new_superdirp = next_new_superdirp;
if (new_superdirp == NIL_INODE) {
/* Missing ".." entry. Assume the worst. */
r = EINVAL;
break;
}
}
}
/* The old or new name must not be . or .. */
if (strcmp(old_name, ".")==0 || strcmp(old_name, "..")==0 ||
strcmp(new_name, ".")==0 || strcmp(new_name, "..")==0) {
r = EINVAL;
}
/* Both parent directories must be on the same device.
if (old_dirp->i_dev != new_dirp->i_dev) r = EXDEV; */
/* Some tests apply only if the new path exists. */
if (new_ip == NIL_INODE) {
/* don't rename a file with a file system mounted on it.
if (old_ip->i_dev != old_dirp->i_dev) r = EXDEV;*/
if (odir && new_dirp->i_nlinks >=
(new_dirp->i_sp->s_version == V1 ? CHAR_MAX : SHRT_MAX) &&
!same_pdir && r == OK) {
r = EMLINK;
}
}
else {
if (old_ip == new_ip) {
r = SAME; /* old=new */
}
/* has the old file or new file a file system mounted on it?
if (old_ip->i_dev != new_ip->i_dev) r = EXDEV;
*/
ndir = ((new_ip->i_mode & I_TYPE) == I_DIRECTORY); /* dir ? */
if (odir == TRUE && ndir == FALSE) {
r = ENOTDIR;
}
if (odir == FALSE && ndir == TRUE) {
r = EISDIR;
}
}
}
/* If a process has another root directory than the system root, we might
* "accidently" be moving it's working directory to a place where it's
* root directory isn't a super directory of it anymore. This can make
* the function chroot useless. If chroot will be used often we should
* probably check for it here.
*/
/* The rename will probably work. Only two things can go wrong now:
* 1. being unable to remove the new file. (when new file already exists)
* 2. being unable to make the new directory entry. (new file doesn't exists)
* [directory has to grow by one block and cannot because the disk
* is completely full].
*/
if (r == OK) {
if (new_ip != NIL_INODE) {
/* There is already an entry for 'new'. Try to remove it. */
if (odir)
r = remove_dir_nocheck(new_dirp, new_ip, new_name);
else
r = unlink_file_nocheck(new_dirp, new_ip, new_name);
}
/* if r is OK, the rename will succeed, while there is now an
* unused entry in the new parent directory.
*/
}
if (r == OK) {
/* If the new name will be in the same parent directory as the old one,
* first remove the old name to free an entry for the new name,
* otherwise first try to create the new name entry to make sure
* the rename will succeed.
*/
numb = old_ip->i_num; /* inode number of old file */
if (same_pdir) {
r = search_dir_nocheck(old_dirp, old_name, (ino_t *) 0, DELETE);
/* shouldn't go wrong. */
if (r==OK) (void) search_dir_nocheck(old_dirp, new_name,
&numb, ENTER);
} else {
r = search_dir_nocheck(new_dirp, new_name, &numb, ENTER);
if (r == OK)
(void) search_dir_nocheck(old_dirp, old_name,
(ino_t *) 0, DELETE);
}
}
/* If r is OK, the ctime and mtime of old_dirp and new_dirp have been marked
* for update in search_dir.
*/
if (r == OK && odir && !same_pdir) {
/* Update the .. entry in the directory (still points to old_dirp). */
numb = new_dirp->i_num;
(void) unlink_file_nocheck(old_ip, NIL_INODE, dot2);
if (search_dir_nocheck(old_ip, dot2, &numb, ENTER) == OK) {
/* New link created. */
new_dirp->i_nlinks++;
new_dirp->i_dirt = DIRTY;
}
}
/* Release the inodes. */
put_inode(old_dirp);
put_inode(old_ip);
put_inode(new_dirp);
put_inode(new_ip);
return(r == SAME ? OK : r);
}
/*===========================================================================*
* fs_trunc *
*===========================================================================*/
PUBLIC int fs_trunc()
{
struct inode *rip;
int r = OK;
caller_uid = fs_m_in.REQ_UID;
caller_gid = fs_m_in.REQ_GID;
/* Temporarily open the file. */
if ( (rip = get_inode(fs_dev, fs_m_in.REQ_INODE_NR)) == NIL_INODE) {
printf("MFS(%d) get_inode by fs_chmod() failed\n", SELF_E);
return(EINVAL);
}
if ( (rip->i_mode & I_TYPE) != I_REGULAR)
r = EINVAL;
else
r = truncate_inode(rip, fs_m_in.REQ_LENGTH);
put_inode(rip);
return r;
}
/*===========================================================================*
* fs_ftrunc *
*===========================================================================*/
PUBLIC int fs_ftrunc(void)
{
struct inode *rip;
off_t start, end;
int r;
if ( (rip = find_inode(fs_dev, fs_m_in.REQ_FD_INODE_NR))
== NIL_INODE) {
printf("FSfreesp: couldn't find inode %d\n",
fs_m_in.REQ_FD_INODE_NR);
return EINVAL;
}
start = fs_m_in.REQ_FD_START;
end = fs_m_in.REQ_FD_END;
if (end == 0) {
r = truncate_inode(rip, start);
}
else {
r = freesp_inode(rip, start, end);
}
return r;
}
/*===========================================================================*
* truncate_inode *
*===========================================================================*/
PUBLIC int truncate_inode(rip, newsize)
register struct inode *rip; /* pointer to inode to be truncated */
off_t newsize; /* inode must become this size */
{
/* Set inode to a certain size, freeing any zones no longer referenced
* and updating the size in the inode. If the inode is extended, the
* extra space is a hole that reads as zeroes.
*
* Nothing special has to happen to file pointers if inode is opened in
* O_APPEND mode, as this is different per fd and is checked when
* writing is done.
*/
zone_t zone_size;
int scale, file_type, waspipe;
dev_t dev;
file_type = rip->i_mode & I_TYPE; /* check to see if file is special */
if (file_type == I_CHAR_SPECIAL || file_type == I_BLOCK_SPECIAL)
return EINVAL;
if(newsize > rip->i_sp->s_max_size) /* don't let inode grow too big */
return EFBIG;
dev = rip->i_dev; /* device on which inode resides */
scale = rip->i_sp->s_log_zone_size;
zone_size = (zone_t) rip->i_sp->s_block_size << scale;
/* Pipes can shrink, so adjust size to make sure all zones are removed. */
waspipe = rip->i_pipe == I_PIPE; /* TRUE if this was a pipe */
if (waspipe) {
if(newsize != 0)
return EINVAL; /* Only truncate pipes to 0. */
rip->i_size = PIPE_SIZE(rip->i_sp->s_block_size);
}
/* Free the actual space if relevant. */
if(newsize < rip->i_size)
freesp_inode(rip, newsize, rip->i_size);
/* Next correct the inode size. */
if(!waspipe) rip->i_size = newsize;
else wipe_inode(rip); /* Pipes can only be truncated to 0. */
rip->i_update |= CTIME | MTIME;
rip->i_dirt = DIRTY;
return OK;
}
/*===========================================================================*
* freesp_inode *
*===========================================================================*/
PUBLIC int freesp_inode(rip, start, end)
register struct inode *rip; /* pointer to inode to be partly freed */
off_t start, end; /* range of bytes to free (end uninclusive) */
{
/* Cut an arbitrary hole in an inode. The caller is responsible for checking
* the reasonableness of the inode type of rip. The reason is this is that
* this function can be called for different reasons, for which different
* sets of inode types are reasonable. Adjusting the final size of the inode
* is to be done by the caller too, if wished.
*
* Consumers of this function currently are truncate_inode() (used to
* free indirect and data blocks for any type of inode, but also to
* implement the ftruncate() and truncate() system calls) and the F_FREESP
* fcntl().
*/
off_t p, e;
int zone_size, dev;
if(end > rip->i_size) /* freeing beyond end makes no sense */
end = rip->i_size;
if(end <= start) /* end is uninclusive, so start<end */
return EINVAL;
zone_size = rip->i_sp->s_block_size << rip->i_sp->s_log_zone_size;
dev = rip->i_dev; /* device on which inode resides */
/* If freeing doesn't cross a zone boundary, then we may only zero
* a range of the block.
*/
if(start/zone_size == (end-1)/zone_size) {
zeroblock_range(rip, start, end-start);
} else {
/* First zero unused part of partly used blocks. */
if(start%zone_size)
zeroblock_half(rip, start, LAST_HALF);
if(end%zone_size && end < rip->i_size)
zeroblock_half(rip, end, FIRST_HALF);
}
/* Now completely free the completely unused blocks.
* write_map() will free unused (double) indirect
* blocks too. Converting the range to zone numbers avoids
* overflow on p when doing e.g. 'p += zone_size'.
*/
e = end/zone_size;
if(end == rip->i_size && (end % zone_size)) e++;
for(p = nextblock(start, zone_size)/zone_size; p < e; p ++)
write_map(rip, p*zone_size, NO_ZONE, WMAP_FREE);
rip->i_update |= CTIME | MTIME;
rip->i_dirt = DIRTY;
return OK;
}
/*===========================================================================*
* nextblock *
*===========================================================================*/
PRIVATE off_t nextblock(pos, zone_size)
off_t pos;
int zone_size;
{
/* Return the first position in the next block after position 'pos'
* (unless this is the first position in the current block).
* This can be done in one expression, but that can overflow pos.
*/
off_t p;
p = (pos/zone_size)*zone_size;
if((pos % zone_size)) p += zone_size; /* Round up. */
return p;
}
/*===========================================================================*
* zeroblock_half *
*===========================================================================*/
PRIVATE void zeroblock_half(rip, pos, half)
struct inode *rip;
off_t pos;
int half;
{
/* Zero the upper or lower 'half' of a block that holds position 'pos'.
* half can be FIRST_HALF or LAST_HALF.
*
* FIRST_HALF: 0..pos-1 will be zeroed
* LAST_HALF: pos..blocksize-1 will be zeroed
*/
int offset, len;
/* Offset of zeroing boundary. */
offset = pos % rip->i_sp->s_block_size;
if(half == LAST_HALF) {
len = rip->i_sp->s_block_size - offset;
} else {
len = offset;
pos -= offset;
offset = 0;
}
zeroblock_range(rip, pos, len);
}
/*===========================================================================*
* zeroblock_range *
*===========================================================================*/
PRIVATE void zeroblock_range(rip, pos, len)
struct inode *rip;
off_t pos;
off_t len;
{
/* Zero a range in a block.
* This function is used to zero a segment of a block, either
* FIRST_HALF of LAST_HALF.
*
*/
block_t b;
struct buf *bp;
off_t offset;
if(!len) return; /* no zeroing to be done. */
if( (b = read_map(rip, pos)) == NO_BLOCK) return;
if( (bp = get_block(rip->i_dev, b, NORMAL)) == NIL_BUF)
panic(__FILE__, "zeroblock_range: no block", NO_NUM);
offset = pos % rip->i_sp->s_block_size;
if(offset + len > rip->i_sp->s_block_size)
panic(__FILE__, "zeroblock_range: len too long", len);
memset(bp->b_data + offset, 0, len);
bp->b_dirt = DIRTY;
put_block(bp, FULL_DATA_BLOCK);
}
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