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| Current File : //compat/linux/proc/self/root/usr/src/bin/pax/tables.c |
/*-
* Copyright (c) 1992 Keith Muller.
* Copyright (c) 1992, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Keith Muller of the University of California, San Diego.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
#if 0
static char sccsid[] = "@(#)tables.c 8.1 (Berkeley) 5/31/93";
#endif
#endif /* not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/bin/pax/tables.c 222177 2011-05-22 14:03:38Z uqs $");
#include <sys/types.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "pax.h"
#include "tables.h"
#include "extern.h"
/*
* Routines for controlling the contents of all the different databases pax
* keeps. Tables are dynamically created only when they are needed. The
* goal was speed and the ability to work with HUGE archives. The databases
* were kept simple, but do have complex rules for when the contents change.
* As of this writing, the POSIX library functions were more complex than
* needed for this application (pax databases have very short lifetimes and
* do not survive after pax is finished). Pax is required to handle very
* large archives. These database routines carefully combine memory usage and
* temporary file storage in ways which will not significantly impact runtime
* performance while allowing the largest possible archives to be handled.
* Trying to force the fit to the POSIX databases routines was not considered
* time well spent.
*/
static HRDLNK **ltab = NULL; /* hard link table for detecting hard links */
static FTM **ftab = NULL; /* file time table for updating arch */
static NAMT **ntab = NULL; /* interactive rename storage table */
static DEVT **dtab = NULL; /* device/inode mapping tables */
static ATDIR **atab = NULL; /* file tree directory time reset table */
static int dirfd = -1; /* storage for setting created dir time/mode */
static u_long dircnt; /* entries in dir time/mode storage */
static int ffd = -1; /* tmp file for file time table name storage */
static DEVT *chk_dev(dev_t, int);
/*
* hard link table routines
*
* The hard link table tries to detect hard links to files using the device and
* inode values. We do this when writing an archive, so we can tell the format
* write routine that this file is a hard link to another file. The format
* write routine then can store this file in whatever way it wants (as a hard
* link if the format supports that like tar, or ignore this info like cpio).
* (Actually a field in the format driver table tells us if the format wants
* hard link info. if not, we do not waste time looking for them). We also use
* the same table when reading an archive. In that situation, this table is
* used by the format read routine to detect hard links from stored dev and
* inode numbers (like cpio). This will allow pax to create a link when one
* can be detected by the archive format.
*/
/*
* lnk_start
* Creates the hard link table.
* Return:
* 0 if created, -1 if failure
*/
int
lnk_start(void)
{
if (ltab != NULL)
return(0);
if ((ltab = (HRDLNK **)calloc(L_TAB_SZ, sizeof(HRDLNK *))) == NULL) {
paxwarn(1, "Cannot allocate memory for hard link table");
return(-1);
}
return(0);
}
/*
* chk_lnk()
* Looks up entry in hard link hash table. If found, it copies the name
* of the file it is linked to (we already saw that file) into ln_name.
* lnkcnt is decremented and if goes to 1 the node is deleted from the
* database. (We have seen all the links to this file). If not found,
* we add the file to the database if it has the potential for having
* hard links to other files we may process (it has a link count > 1)
* Return:
* if found returns 1; if not found returns 0; -1 on error
*/
int
chk_lnk(ARCHD *arcn)
{
HRDLNK *pt;
HRDLNK **ppt;
u_int indx;
if (ltab == NULL)
return(-1);
/*
* ignore those nodes that cannot have hard links
*/
if ((arcn->type == PAX_DIR) || (arcn->sb.st_nlink <= 1))
return(0);
/*
* hash inode number and look for this file
*/
indx = ((unsigned)arcn->sb.st_ino) % L_TAB_SZ;
if ((pt = ltab[indx]) != NULL) {
/*
* it's hash chain in not empty, walk down looking for it
*/
ppt = &(ltab[indx]);
while (pt != NULL) {
if ((pt->ino == arcn->sb.st_ino) &&
(pt->dev == arcn->sb.st_dev))
break;
ppt = &(pt->fow);
pt = pt->fow;
}
if (pt != NULL) {
/*
* found a link. set the node type and copy in the
* name of the file it is to link to. we need to
* handle hardlinks to regular files differently than
* other links.
*/
arcn->ln_nlen = l_strncpy(arcn->ln_name, pt->name,
sizeof(arcn->ln_name) - 1);
arcn->ln_name[arcn->ln_nlen] = '\0';
if (arcn->type == PAX_REG)
arcn->type = PAX_HRG;
else
arcn->type = PAX_HLK;
/*
* if we have found all the links to this file, remove
* it from the database
*/
if (--pt->nlink <= 1) {
*ppt = pt->fow;
free(pt->name);
free(pt);
}
return(1);
}
}
/*
* we never saw this file before. It has links so we add it to the
* front of this hash chain
*/
if ((pt = (HRDLNK *)malloc(sizeof(HRDLNK))) != NULL) {
if ((pt->name = strdup(arcn->name)) != NULL) {
pt->dev = arcn->sb.st_dev;
pt->ino = arcn->sb.st_ino;
pt->nlink = arcn->sb.st_nlink;
pt->fow = ltab[indx];
ltab[indx] = pt;
return(0);
}
free(pt);
}
paxwarn(1, "Hard link table out of memory");
return(-1);
}
/*
* purg_lnk
* remove reference for a file that we may have added to the data base as
* a potential source for hard links. We ended up not using the file, so
* we do not want to accidentally point another file at it later on.
*/
void
purg_lnk(ARCHD *arcn)
{
HRDLNK *pt;
HRDLNK **ppt;
u_int indx;
if (ltab == NULL)
return;
/*
* do not bother to look if it could not be in the database
*/
if ((arcn->sb.st_nlink <= 1) || (arcn->type == PAX_DIR) ||
(arcn->type == PAX_HLK) || (arcn->type == PAX_HRG))
return;
/*
* find the hash chain for this inode value, if empty return
*/
indx = ((unsigned)arcn->sb.st_ino) % L_TAB_SZ;
if ((pt = ltab[indx]) == NULL)
return;
/*
* walk down the list looking for the inode/dev pair, unlink and
* free if found
*/
ppt = &(ltab[indx]);
while (pt != NULL) {
if ((pt->ino == arcn->sb.st_ino) &&
(pt->dev == arcn->sb.st_dev))
break;
ppt = &(pt->fow);
pt = pt->fow;
}
if (pt == NULL)
return;
/*
* remove and free it
*/
*ppt = pt->fow;
free(pt->name);
free(pt);
}
/*
* lnk_end()
* Pull apart an existing link table so we can reuse it. We do this between
* read and write phases of append with update. (The format may have
* used the link table, and we need to start with a fresh table for the
* write phase).
*/
void
lnk_end(void)
{
int i;
HRDLNK *pt;
HRDLNK *ppt;
if (ltab == NULL)
return;
for (i = 0; i < L_TAB_SZ; ++i) {
if (ltab[i] == NULL)
continue;
pt = ltab[i];
ltab[i] = NULL;
/*
* free up each entry on this chain
*/
while (pt != NULL) {
ppt = pt;
pt = ppt->fow;
free(ppt->name);
free(ppt);
}
}
return;
}
/*
* modification time table routines
*
* The modification time table keeps track of last modification times for all
* files stored in an archive during a write phase when -u is set. We only
* add a file to the archive if it is newer than a file with the same name
* already stored on the archive (if there is no other file with the same
* name on the archive it is added). This applies to writes and appends.
* An append with an -u must read the archive and store the modification time
* for every file on that archive before starting the write phase. It is clear
* that this is one HUGE database. To save memory space, the actual file names
* are stored in a scratch file and indexed by an in memory hash table. The
* hash table is indexed by hashing the file path. The nodes in the table store
* the length of the filename and the lseek offset within the scratch file
* where the actual name is stored. Since there are never any deletions to this
* table, fragmentation of the scratch file is never an issue. Lookups seem to
* not exhibit any locality at all (files in the database are rarely
* looked up more than once...). So caching is just a waste of memory. The
* only limitation is the amount of scratch file space available to store the
* path names.
*/
/*
* ftime_start()
* create the file time hash table and open for read/write the scratch
* file. (after created it is unlinked, so when we exit we leave
* no witnesses).
* Return:
* 0 if the table and file was created ok, -1 otherwise
*/
int
ftime_start(void)
{
if (ftab != NULL)
return(0);
if ((ftab = (FTM **)calloc(F_TAB_SZ, sizeof(FTM *))) == NULL) {
paxwarn(1, "Cannot allocate memory for file time table");
return(-1);
}
/*
* get random name and create temporary scratch file, unlink name
* so it will get removed on exit
*/
memcpy(tempbase, _TFILE_BASE, sizeof(_TFILE_BASE));
if ((ffd = mkstemp(tempfile)) < 0) {
syswarn(1, errno, "Unable to create temporary file: %s",
tempfile);
return(-1);
}
(void)unlink(tempfile);
return(0);
}
/*
* chk_ftime()
* looks up entry in file time hash table. If not found, the file is
* added to the hash table and the file named stored in the scratch file.
* If a file with the same name is found, the file times are compared and
* the most recent file time is retained. If the new file was younger (or
* was not in the database) the new file is selected for storage.
* Return:
* 0 if file should be added to the archive, 1 if it should be skipped,
* -1 on error
*/
int
chk_ftime(ARCHD *arcn)
{
FTM *pt;
int namelen;
u_int indx;
char ckname[PAXPATHLEN+1];
/*
* no info, go ahead and add to archive
*/
if (ftab == NULL)
return(0);
/*
* hash the pathname and look up in table
*/
namelen = arcn->nlen;
indx = st_hash(arcn->name, namelen, F_TAB_SZ);
if ((pt = ftab[indx]) != NULL) {
/*
* the hash chain is not empty, walk down looking for match
* only read up the path names if the lengths match, speeds
* up the search a lot
*/
while (pt != NULL) {
if (pt->namelen == namelen) {
/*
* potential match, have to read the name
* from the scratch file.
*/
if (lseek(ffd,pt->seek,SEEK_SET) != pt->seek) {
syswarn(1, errno,
"Failed ftime table seek");
return(-1);
}
if (read(ffd, ckname, namelen) != namelen) {
syswarn(1, errno,
"Failed ftime table read");
return(-1);
}
/*
* if the names match, we are done
*/
if (!strncmp(ckname, arcn->name, namelen))
break;
}
/*
* try the next entry on the chain
*/
pt = pt->fow;
}
if (pt != NULL) {
/*
* found the file, compare the times, save the newer
*/
if (arcn->sb.st_mtime > pt->mtime) {
/*
* file is newer
*/
pt->mtime = arcn->sb.st_mtime;
return(0);
}
/*
* file is older
*/
return(1);
}
}
/*
* not in table, add it
*/
if ((pt = (FTM *)malloc(sizeof(FTM))) != NULL) {
/*
* add the name at the end of the scratch file, saving the
* offset. add the file to the head of the hash chain
*/
if ((pt->seek = lseek(ffd, (off_t)0, SEEK_END)) >= 0) {
if (write(ffd, arcn->name, namelen) == namelen) {
pt->mtime = arcn->sb.st_mtime;
pt->namelen = namelen;
pt->fow = ftab[indx];
ftab[indx] = pt;
return(0);
}
syswarn(1, errno, "Failed write to file time table");
} else
syswarn(1, errno, "Failed seek on file time table");
} else
paxwarn(1, "File time table ran out of memory");
if (pt != NULL)
free(pt);
return(-1);
}
/*
* Interactive rename table routines
*
* The interactive rename table keeps track of the new names that the user
* assigns to files from tty input. Since this map is unique for each file
* we must store it in case there is a reference to the file later in archive
* (a link). Otherwise we will be unable to find the file we know was
* extracted. The remapping of these files is stored in a memory based hash
* table (it is assumed since input must come from /dev/tty, it is unlikely to
* be a very large table).
*/
/*
* name_start()
* create the interactive rename table
* Return:
* 0 if successful, -1 otherwise
*/
int
name_start(void)
{
if (ntab != NULL)
return(0);
if ((ntab = (NAMT **)calloc(N_TAB_SZ, sizeof(NAMT *))) == NULL) {
paxwarn(1, "Cannot allocate memory for interactive rename table");
return(-1);
}
return(0);
}
/*
* add_name()
* add the new name to old name mapping just created by the user.
* If an old name mapping is found (there may be duplicate names on an
* archive) only the most recent is kept.
* Return:
* 0 if added, -1 otherwise
*/
int
add_name(char *oname, int onamelen, char *nname)
{
NAMT *pt;
u_int indx;
if (ntab == NULL) {
/*
* should never happen
*/
paxwarn(0, "No interactive rename table, links may fail\n");
return(0);
}
/*
* look to see if we have already mapped this file, if so we
* will update it
*/
indx = st_hash(oname, onamelen, N_TAB_SZ);
if ((pt = ntab[indx]) != NULL) {
/*
* look down the has chain for the file
*/
while ((pt != NULL) && (strcmp(oname, pt->oname) != 0))
pt = pt->fow;
if (pt != NULL) {
/*
* found an old mapping, replace it with the new one
* the user just input (if it is different)
*/
if (strcmp(nname, pt->nname) == 0)
return(0);
free(pt->nname);
if ((pt->nname = strdup(nname)) == NULL) {
paxwarn(1, "Cannot update rename table");
return(-1);
}
return(0);
}
}
/*
* this is a new mapping, add it to the table
*/
if ((pt = (NAMT *)malloc(sizeof(NAMT))) != NULL) {
if ((pt->oname = strdup(oname)) != NULL) {
if ((pt->nname = strdup(nname)) != NULL) {
pt->fow = ntab[indx];
ntab[indx] = pt;
return(0);
}
free(pt->oname);
}
free(pt);
}
paxwarn(1, "Interactive rename table out of memory");
return(-1);
}
/*
* sub_name()
* look up a link name to see if it points at a file that has been
* remapped by the user. If found, the link is adjusted to contain the
* new name (oname is the link to name)
*/
void
sub_name(char *oname, int *onamelen, size_t onamesize)
{
NAMT *pt;
u_int indx;
if (ntab == NULL)
return;
/*
* look the name up in the hash table
*/
indx = st_hash(oname, *onamelen, N_TAB_SZ);
if ((pt = ntab[indx]) == NULL)
return;
while (pt != NULL) {
/*
* walk down the hash chain looking for a match
*/
if (strcmp(oname, pt->oname) == 0) {
/*
* found it, replace it with the new name
* and return (we know that oname has enough space)
*/
*onamelen = l_strncpy(oname, pt->nname, onamesize - 1);
oname[*onamelen] = '\0';
return;
}
pt = pt->fow;
}
/*
* no match, just return
*/
return;
}
/*
* device/inode mapping table routines
* (used with formats that store device and inodes fields)
*
* device/inode mapping tables remap the device field in an archive header. The
* device/inode fields are used to determine when files are hard links to each
* other. However these values have very little meaning outside of that. This
* database is used to solve one of two different problems.
*
* 1) when files are appended to an archive, while the new files may have hard
* links to each other, you cannot determine if they have hard links to any
* file already stored on the archive from a prior run of pax. We must assume
* that these inode/device pairs are unique only within a SINGLE run of pax
* (which adds a set of files to an archive). So we have to make sure the
* inode/dev pairs we add each time are always unique. We do this by observing
* while the inode field is very dense, the use of the dev field is fairly
* sparse. Within each run of pax, we remap any device number of a new archive
* member that has a device number used in a prior run and already stored in a
* file on the archive. During the read phase of the append, we store the
* device numbers used and mark them to not be used by any file during the
* write phase. If during write we go to use one of those old device numbers,
* we remap it to a new value.
*
* 2) Often the fields in the archive header used to store these values are
* too small to store the entire value. The result is an inode or device value
* which can be truncated. This really can foul up an archive. With truncation
* we end up creating links between files that are really not links (after
* truncation the inodes are the same value). We address that by detecting
* truncation and forcing a remap of the device field to split truncated
* inodes away from each other. Each truncation creates a pattern of bits that
* are removed. We use this pattern of truncated bits to partition the inodes
* on a single device to many different devices (each one represented by the
* truncated bit pattern). All inodes on the same device that have the same
* truncation pattern are mapped to the same new device. Two inodes that
* truncate to the same value clearly will always have different truncation
* bit patterns, so they will be split from away each other. When we spot
* device truncation we remap the device number to a non truncated value.
* (for more info see table.h for the data structures involved).
*/
/*
* dev_start()
* create the device mapping table
* Return:
* 0 if successful, -1 otherwise
*/
int
dev_start(void)
{
if (dtab != NULL)
return(0);
if ((dtab = (DEVT **)calloc(D_TAB_SZ, sizeof(DEVT *))) == NULL) {
paxwarn(1, "Cannot allocate memory for device mapping table");
return(-1);
}
return(0);
}
/*
* add_dev()
* add a device number to the table. this will force the device to be
* remapped to a new value if it be used during a write phase. This
* function is called during the read phase of an append to prohibit the
* use of any device number already in the archive.
* Return:
* 0 if added ok, -1 otherwise
*/
int
add_dev(ARCHD *arcn)
{
if (chk_dev(arcn->sb.st_dev, 1) == NULL)
return(-1);
return(0);
}
/*
* chk_dev()
* check for a device value in the device table. If not found and the add
* flag is set, it is added. This does NOT assign any mapping values, just
* adds the device number as one that need to be remapped. If this device
* is already mapped, just return with a pointer to that entry.
* Return:
* pointer to the entry for this device in the device map table. Null
* if the add flag is not set and the device is not in the table (it is
* not been seen yet). If add is set and the device cannot be added, null
* is returned (indicates an error).
*/
static DEVT *
chk_dev(dev_t dev, int add)
{
DEVT *pt;
u_int indx;
if (dtab == NULL)
return(NULL);
/*
* look to see if this device is already in the table
*/
indx = ((unsigned)dev) % D_TAB_SZ;
if ((pt = dtab[indx]) != NULL) {
while ((pt != NULL) && (pt->dev != dev))
pt = pt->fow;
/*
* found it, return a pointer to it
*/
if (pt != NULL)
return(pt);
}
/*
* not in table, we add it only if told to as this may just be a check
* to see if a device number is being used.
*/
if (add == 0)
return(NULL);
/*
* allocate a node for this device and add it to the front of the hash
* chain. Note we do not assign remaps values here, so the pt->list
* list must be NULL.
*/
if ((pt = (DEVT *)malloc(sizeof(DEVT))) == NULL) {
paxwarn(1, "Device map table out of memory");
return(NULL);
}
pt->dev = dev;
pt->list = NULL;
pt->fow = dtab[indx];
dtab[indx] = pt;
return(pt);
}
/*
* map_dev()
* given an inode and device storage mask (the mask has a 1 for each bit
* the archive format is able to store in a header), we check for inode
* and device truncation and remap the device as required. Device mapping
* can also occur when during the read phase of append a device number was
* seen (and was marked as do not use during the write phase). WE ASSUME
* that unsigned longs are the same size or bigger than the fields used
* for ino_t and dev_t. If not the types will have to be changed.
* Return:
* 0 if all ok, -1 otherwise.
*/
int
map_dev(ARCHD *arcn, u_long dev_mask, u_long ino_mask)
{
DEVT *pt;
DLIST *dpt;
static dev_t lastdev = 0; /* next device number to try */
int trc_ino = 0;
int trc_dev = 0;
ino_t trunc_bits = 0;
ino_t nino;
if (dtab == NULL)
return(0);
/*
* check for device and inode truncation, and extract the truncated
* bit pattern.
*/
if ((arcn->sb.st_dev & (dev_t)dev_mask) != arcn->sb.st_dev)
++trc_dev;
if ((nino = arcn->sb.st_ino & (ino_t)ino_mask) != arcn->sb.st_ino) {
++trc_ino;
trunc_bits = arcn->sb.st_ino & (ino_t)(~ino_mask);
}
/*
* see if this device is already being mapped, look up the device
* then find the truncation bit pattern which applies
*/
if ((pt = chk_dev(arcn->sb.st_dev, 0)) != NULL) {
/*
* this device is already marked to be remapped
*/
for (dpt = pt->list; dpt != NULL; dpt = dpt->fow)
if (dpt->trunc_bits == trunc_bits)
break;
if (dpt != NULL) {
/*
* we are being remapped for this device and pattern
* change the device number to be stored and return
*/
arcn->sb.st_dev = dpt->dev;
arcn->sb.st_ino = nino;
return(0);
}
} else {
/*
* this device is not being remapped YET. if we do not have any
* form of truncation, we do not need a remap
*/
if (!trc_ino && !trc_dev)
return(0);
/*
* we have truncation, have to add this as a device to remap
*/
if ((pt = chk_dev(arcn->sb.st_dev, 1)) == NULL)
goto bad;
/*
* if we just have a truncated inode, we have to make sure that
* all future inodes that do not truncate (they have the
* truncation pattern of all 0's) continue to map to the same
* device number. We probably have already written inodes with
* this device number to the archive with the truncation
* pattern of all 0's. So we add the mapping for all 0's to the
* same device number.
*/
if (!trc_dev && (trunc_bits != 0)) {
if ((dpt = (DLIST *)malloc(sizeof(DLIST))) == NULL)
goto bad;
dpt->trunc_bits = 0;
dpt->dev = arcn->sb.st_dev;
dpt->fow = pt->list;
pt->list = dpt;
}
}
/*
* look for a device number not being used. We must watch for wrap
* around on lastdev (so we do not get stuck looking forever!)
*/
while (++lastdev > 0) {
if (chk_dev(lastdev, 0) != NULL)
continue;
/*
* found an unused value. If we have reached truncation point
* for this format we are hosed, so we give up. Otherwise we
* mark it as being used.
*/
if (((lastdev & ((dev_t)dev_mask)) != lastdev) ||
(chk_dev(lastdev, 1) == NULL))
goto bad;
break;
}
if ((lastdev <= 0) || ((dpt = (DLIST *)malloc(sizeof(DLIST))) == NULL))
goto bad;
/*
* got a new device number, store it under this truncation pattern.
* change the device number this file is being stored with.
*/
dpt->trunc_bits = trunc_bits;
dpt->dev = lastdev;
dpt->fow = pt->list;
pt->list = dpt;
arcn->sb.st_dev = lastdev;
arcn->sb.st_ino = nino;
return(0);
bad:
paxwarn(1, "Unable to fix truncated inode/device field when storing %s",
arcn->name);
paxwarn(0, "Archive may create improper hard links when extracted");
return(0);
}
/*
* directory access/mod time reset table routines (for directories READ by pax)
*
* The pax -t flag requires that access times of archive files to be the same
* before being read by pax. For regular files, access time is restored after
* the file has been copied. This database provides the same functionality for
* directories read during file tree traversal. Restoring directory access time
* is more complex than files since directories may be read several times until
* all the descendants in their subtree are visited by fts. Directory access
* and modification times are stored during the fts pre-order visit (done
* before any descendants in the subtree is visited) and restored after the
* fts post-order visit (after all the descendants have been visited). In the
* case of premature exit from a subtree (like from the effects of -n), any
* directory entries left in this database are reset during final cleanup
* operations of pax. Entries are hashed by inode number for fast lookup.
*/
/*
* atdir_start()
* create the directory access time database for directories READ by pax.
* Return:
* 0 is created ok, -1 otherwise.
*/
int
atdir_start(void)
{
if (atab != NULL)
return(0);
if ((atab = (ATDIR **)calloc(A_TAB_SZ, sizeof(ATDIR *))) == NULL) {
paxwarn(1,"Cannot allocate space for directory access time table");
return(-1);
}
return(0);
}
/*
* atdir_end()
* walk through the directory access time table and reset the access time
* of any directory who still has an entry left in the database. These
* entries are for directories READ by pax
*/
void
atdir_end(void)
{
ATDIR *pt;
int i;
if (atab == NULL)
return;
/*
* for each non-empty hash table entry reset all the directories
* chained there.
*/
for (i = 0; i < A_TAB_SZ; ++i) {
if ((pt = atab[i]) == NULL)
continue;
/*
* remember to force the times, set_ftime() looks at pmtime
* and patime, which only applies to things CREATED by pax,
* not read by pax. Read time reset is controlled by -t.
*/
for (; pt != NULL; pt = pt->fow)
set_ftime(pt->name, pt->mtime, pt->atime, 1);
}
}
/*
* add_atdir()
* add a directory to the directory access time table. Table is hashed
* and chained by inode number. This is for directories READ by pax
*/
void
add_atdir(char *fname, dev_t dev, ino_t ino, time_t mtime, time_t atime)
{
ATDIR *pt;
u_int indx;
if (atab == NULL)
return;
/*
* make sure this directory is not already in the table, if so just
* return (the older entry always has the correct time). The only
* way this will happen is when the same subtree can be traversed by
* different args to pax and the -n option is aborting fts out of a
* subtree before all the post-order visits have been made).
*/
indx = ((unsigned)ino) % A_TAB_SZ;
if ((pt = atab[indx]) != NULL) {
while (pt != NULL) {
if ((pt->ino == ino) && (pt->dev == dev))
break;
pt = pt->fow;
}
/*
* oops, already there. Leave it alone.
*/
if (pt != NULL)
return;
}
/*
* add it to the front of the hash chain
*/
if ((pt = (ATDIR *)malloc(sizeof(ATDIR))) != NULL) {
if ((pt->name = strdup(fname)) != NULL) {
pt->dev = dev;
pt->ino = ino;
pt->mtime = mtime;
pt->atime = atime;
pt->fow = atab[indx];
atab[indx] = pt;
return;
}
free(pt);
}
paxwarn(1, "Directory access time reset table ran out of memory");
return;
}
/*
* get_atdir()
* look up a directory by inode and device number to obtain the access
* and modification time you want to set to. If found, the modification
* and access time parameters are set and the entry is removed from the
* table (as it is no longer needed). These are for directories READ by
* pax
* Return:
* 0 if found, -1 if not found.
*/
int
get_atdir(dev_t dev, ino_t ino, time_t *mtime, time_t *atime)
{
ATDIR *pt;
ATDIR **ppt;
u_int indx;
if (atab == NULL)
return(-1);
/*
* hash by inode and search the chain for an inode and device match
*/
indx = ((unsigned)ino) % A_TAB_SZ;
if ((pt = atab[indx]) == NULL)
return(-1);
ppt = &(atab[indx]);
while (pt != NULL) {
if ((pt->ino == ino) && (pt->dev == dev))
break;
/*
* no match, go to next one
*/
ppt = &(pt->fow);
pt = pt->fow;
}
/*
* return if we did not find it.
*/
if (pt == NULL)
return(-1);
/*
* found it. return the times and remove the entry from the table.
*/
*ppt = pt->fow;
*mtime = pt->mtime;
*atime = pt->atime;
free(pt->name);
free(pt);
return(0);
}
/*
* directory access mode and time storage routines (for directories CREATED
* by pax).
*
* Pax requires that extracted directories, by default, have their access/mod
* times and permissions set to the values specified in the archive. During the
* actions of extracting (and creating the destination subtree during -rw copy)
* directories extracted may be modified after being created. Even worse is
* that these directories may have been created with file permissions which
* prohibits any descendants of these directories from being extracted. When
* directories are created by pax, access rights may be added to permit the
* creation of files in their subtree. Every time pax creates a directory, the
* times and file permissions specified by the archive are stored. After all
* files have been extracted (or copied), these directories have their times
* and file modes reset to the stored values. The directory info is restored in
* reverse order as entries were added to the data file from root to leaf. To
* restore atime properly, we must go backwards. The data file consists of
* records with two parts, the file name followed by a DIRDATA trailer. The
* fixed sized trailer contains the size of the name plus the off_t location in
* the file. To restore we work backwards through the file reading the trailer
* then the file name.
*/
/*
* dir_start()
* set up the directory time and file mode storage for directories CREATED
* by pax.
* Return:
* 0 if ok, -1 otherwise
*/
int
dir_start(void)
{
if (dirfd != -1)
return(0);
/*
* unlink the file so it goes away at termination by itself
*/
memcpy(tempbase, _TFILE_BASE, sizeof(_TFILE_BASE));
if ((dirfd = mkstemp(tempfile)) >= 0) {
(void)unlink(tempfile);
return(0);
}
paxwarn(1, "Unable to create temporary file for directory times: %s",
tempfile);
return(-1);
}
/*
* add_dir()
* add the mode and times for a newly CREATED directory
* name is name of the directory, psb the stat buffer with the data in it,
* frc_mode is a flag that says whether to force the setting of the mode
* (ignoring the user set values for preserving file mode). Frc_mode is
* for the case where we created a file and found that the resulting
* directory was not writeable and the user asked for file modes to NOT
* be preserved. (we have to preserve what was created by default, so we
* have to force the setting at the end. this is stated explicitly in the
* pax spec)
*/
void
add_dir(char *name, int nlen, struct stat *psb, int frc_mode)
{
DIRDATA dblk;
if (dirfd < 0)
return;
/*
* get current position (where file name will start) so we can store it
* in the trailer
*/
if ((dblk.npos = lseek(dirfd, 0L, SEEK_CUR)) < 0) {
paxwarn(1,"Unable to store mode and times for directory: %s",name);
return;
}
/*
* write the file name followed by the trailer
*/
dblk.nlen = nlen + 1;
dblk.mode = psb->st_mode & 0xffff;
dblk.mtime = psb->st_mtime;
dblk.atime = psb->st_atime;
dblk.frc_mode = frc_mode;
if ((write(dirfd, name, dblk.nlen) == dblk.nlen) &&
(write(dirfd, (char *)&dblk, sizeof(dblk)) == sizeof(dblk))) {
++dircnt;
return;
}
paxwarn(1,"Unable to store mode and times for created directory: %s",name);
return;
}
/*
* proc_dir()
* process all file modes and times stored for directories CREATED
* by pax
*/
void
proc_dir(void)
{
char name[PAXPATHLEN+1];
DIRDATA dblk;
u_long cnt;
if (dirfd < 0)
return;
/*
* read backwards through the file and process each directory
*/
for (cnt = 0; cnt < dircnt; ++cnt) {
/*
* read the trailer, then the file name, if this fails
* just give up.
*/
if (lseek(dirfd, -((off_t)sizeof(dblk)), SEEK_CUR) < 0)
break;
if (read(dirfd,(char *)&dblk, sizeof(dblk)) != sizeof(dblk))
break;
if (lseek(dirfd, dblk.npos, SEEK_SET) < 0)
break;
if (read(dirfd, name, dblk.nlen) != dblk.nlen)
break;
if (lseek(dirfd, dblk.npos, SEEK_SET) < 0)
break;
/*
* frc_mode set, make sure we set the file modes even if
* the user didn't ask for it (see file_subs.c for more info)
*/
if (pmode || dblk.frc_mode)
set_pmode(name, dblk.mode);
if (patime || pmtime)
set_ftime(name, dblk.mtime, dblk.atime, 0);
}
(void)close(dirfd);
dirfd = -1;
if (cnt != dircnt)
paxwarn(1,"Unable to set mode and times for created directories");
return;
}
/*
* database independent routines
*/
/*
* st_hash()
* hashes filenames to a u_int for hashing into a table. Looks at the tail
* end of file, as this provides far better distribution than any other
* part of the name. For performance reasons we only care about the last
* MAXKEYLEN chars (should be at LEAST large enough to pick off the file
* name). Was tested on 500,000 name file tree traversal from the root
* and gave almost a perfectly uniform distribution of keys when used with
* prime sized tables (MAXKEYLEN was 128 in test). Hashes (sizeof int)
* chars at a time and pads with 0 for last addition.
* Return:
* the hash value of the string MOD (%) the table size.
*/
u_int
st_hash(char *name, int len, int tabsz)
{
char *pt;
char *dest;
char *end;
int i;
u_int key = 0;
int steps;
int res;
u_int val;
/*
* only look at the tail up to MAXKEYLEN, we do not need to waste
* time here (remember these are pathnames, the tail is what will
* spread out the keys)
*/
if (len > MAXKEYLEN) {
pt = &(name[len - MAXKEYLEN]);
len = MAXKEYLEN;
} else
pt = name;
/*
* calculate the number of u_int size steps in the string and if
* there is a runt to deal with
*/
steps = len/sizeof(u_int);
res = len % sizeof(u_int);
/*
* add up the value of the string in unsigned integer sized pieces
* too bad we cannot have unsigned int aligned strings, then we
* could avoid the expensive copy.
*/
for (i = 0; i < steps; ++i) {
end = pt + sizeof(u_int);
dest = (char *)&val;
while (pt < end)
*dest++ = *pt++;
key += val;
}
/*
* add in the runt padded with zero to the right
*/
if (res) {
val = 0;
end = pt + res;
dest = (char *)&val;
while (pt < end)
*dest++ = *pt++;
key += val;
}
/*
* return the result mod the table size
*/
return(key % tabsz);
}