/
tables.c
1958 lines (1765 loc) · 52.7 KB
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tables.c
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/* $OpenBSD: tables.c,v 1.53 2017/09/16 07:42:34 otto Exp $ */
/* $NetBSD: tables.c,v 1.4 1995/03/21 09:07:45 cgd Exp $ */
/*-
* Copyright (c) 2005, 2012, 2015, 2016, 2018, 2019
* mirabilos <m@mirbsd.org>
* Copyright (c) 2011
* Svante Signell <svante.signell@telia.com>
* Guillem Jover <guillem@debian.org>
* 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.
* 3. 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.
*/
#include <sys/types.h>
#if HAVE_BOTH_TIME_H
#include <sys/time.h>
#include <time.h>
#elif HAVE_SYS_TIME_H
#include <sys/time.h>
#elif HAVE_TIME_H
#include <time.h>
#endif
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#if HAVE_STRINGS_H
#include <strings.h>
#endif
#include <unistd.h>
#include "pax.h"
#include "ftimes.h"
#include "extern.h"
__RCSID("$MirOS: src/bin/pax/tables.c,v 1.32 2021/08/19 00:34:29 tg Exp $");
#if (_POSIX_VERSION >= 200809L) || (defined(MirBSD) && (MirBSD > 0x0AB9))
#define REALPATH_CAN_ALLOCATE
#endif
/*
* 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 database routines was not considered
* time well spent.
*/
/*
* data structures and constants used by the different databases kept by pax
*/
/*
* Hash Table Sizes MUST BE PRIME, if set too small performance suffers.
* Probably safe to expect 500000 inodes per tape. Assuming good key
* distribution (inodes) chains of under 50 long (worst case) is ok.
*/
#define L_TAB_SZ 2503 /* hard link hash table size */
#define F_TAB_SZ 50503 /* file time hash table size */
#define N_TAB_SZ 541 /* interactive rename hash table */
#define D_TAB_SZ 317 /* unique device mapping table */
#define A_TAB_SZ 317 /* ftree dir access time reset table */
#define SL_TAB_SZ 317 /* escape symlink tables */
#define MAXKEYLEN 64 /* max number of chars for hash */
#define DIRP_SIZE 64 /* initial size of created dir table */
/*
* file hard link structure (hashed by dev/ino and chained) used to find the
* hard links in a filesystem or with some archive formats (cpio)
*/
typedef struct hrdlnk {
ino_t ino; /* files inode number */
char *name; /* name of first file seen with this ino/dev */
dev_t dev; /* files device number */
u_long nlink; /* expected link count */
struct hrdlnk *fow;
} HRDLNK;
/*
* Archive write update file time table (the -u, -C flag), hashed by filename.
* Filenames are stored in a scratch file at seek offset into the file. The
* file time (mod time) and the file name length (for a quick check) are
* stored in a hash table node. We were forced to use a scratch file because
* with -u, the mtime for every node in the archive must always be available
* to compare against (and this data can get REALLY large with big archives).
* By being careful to read only when we have a good chance of a match, the
* performance loss is not measurable (and the size of the archive we can
* handle is greatly increased).
*/
typedef struct ftm {
off_t seek; /* location in scratch file */
struct ftm *fow;
int namelen; /* file name length */
struct stat sb; /* files last modification time */
} FTM;
/*
* Interactive rename table (-i flag), hashed by orig filename.
* We assume this will not be a large table as this mapping data can only be
* obtained through interactive input by the user. Nobody is going to type in
* changes for 500000 files? We use chaining to resolve collisions.
*/
typedef struct namt {
char *oname; /* old name */
char *nname; /* new name typed in by the user */
struct namt *fow;
} NAMT;
/*
* Unique device mapping tables. Some protocols (e.g. cpio) require that the
* <c_dev,c_ino> pair will uniquely identify a file in an archive unless they
* are links to the same file. Appending to archives can break this. For those
* protocols that have this requirement we map c_dev to a unique value not seen
* in the archive when we append. We also try to handle inode truncation with
* this table. (When the inode field in the archive header are too small, we
* remap the dev on writes to remove accidental collisions).
*
* The list is hashed by device number using chain collision resolution. Off of
* each DEVT are linked the various remaps for this device based on those bits
* in the inode which were truncated. For example if we are just remapping to
* avoid a device number during an update append, off the DEVT we would have
* only a single DLIST that has a truncation id of 0 (no inode bits were
* stripped for this device so far). When we spot inode truncation we create
* a new mapping based on the set of bits in the inode which were stripped off.
* so if the top four bits of the inode are stripped and they have a pattern of
* 0110...... (where . are those bits not truncated) we would have a mapping
* assigned for all inodes that has the same 0110.... pattern (with this dev
* number of course). This keeps the mapping sparse and should be able to store
* close to the limit of files which can be represented by the optimal
* combination of dev and inode bits, and without creating a fouled up archive.
* Note we also remap truncated devs in the same way (an exercise for the
* dedicated reader; always wanted to say that...:)
*/
typedef struct devt {
dev_t dev; /* the orig device number we now have to map */
struct devt *fow; /* new device map list */
struct dlist *list; /* map list based on inode truncation bits */
} DEVT;
typedef struct dlist {
ino_t trunc_bits; /* truncation pattern for a specific map */
dev_t dev; /* the new device id we use */
struct dlist *fow;
} DLIST;
/*
* ftree directory access time reset table. When we are done with a
* subtree we reset the access and mod time of the directory when the tflag is
* set. Not really explicitly specified in the pax spec, but easy and fast to
* do (and this may have even been intended in the spec, it is not clear).
* table is hashed by inode with chaining.
*/
typedef struct atdir {
struct file_times ft;
struct atdir *fow;
} ATDIR;
/*
* created directory time and mode storage entry. After pax is finished during
* extraction or copy, we must reset directory access modes and times that
* may have been modified after creation (they no longer have the specified
* times and/or modes). We must reset time in the reverse order of creation,
* because entries are added from the top of the file tree to the bottom.
* We MUST reset times from leaf to root (it will not work the other
* direction).
*/
typedef struct dirdata {
struct file_times ft;
mode_t tr_mode; /* file mode to restore */
paxbool frc_mode; /* do we force mode settings? */
} DIRDATA;
/*
* file hard link structure (hashed by dev/ino and chained) for anonymisation
*/
typedef struct hrdflnk {
dev_t dev; /* files device number */
ino_t ino; /* files inode number */
u_long nlink; /* expected link count */
ino_t newi; /* new inode number */
struct hrdflnk *fow;
} HRDFLNK;
static HRDLNK **ltab = NULL; /* hard link table for detecting hard links */
static HRDFLNK **fltab = NULL; /* hard link table for anonymisation */
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 DIRDATA *dirp = NULL; /* storage for setting created dir time/mode */
static size_t dirsize; /* size of dirp table */
static size_t dircnt = 0; /* 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);
#ifndef REALPATH_CAN_ALLOCATE
static char realname[PATH_MAX];
#endif
static char *
xrealpath(const char *path)
{
#ifndef REALPATH_CAN_ALLOCATE
char *rv;
if ((rv = realpath(path, realname)))
rv = strdup(rv);
return (rv);
#else
return (realpath(path, NULL));
#endif
}
/*
* 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 = calloc(L_TAB_SZ, sizeof(HRDLNK *))) == NULL) {
paxwarn(1, "%s for %s", "Out of memory",
"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;
unsigned 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) {
/*
* its 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 = strlcpy(arcn->ln_name, pt->name,
sizeof(arcn->ln_name));
/* XXX truncate? */
if ((size_t)arcn->nlen >= sizeof(arcn->name))
arcn->nlen = sizeof(arcn->name) - 1;
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 = 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, "%s for %s", "Out of memory", "hard link table");
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 accidently point another file at it later on.
*/
void
purg_lnk(ARCHD *arcn)
{
HRDLNK *pt;
HRDLNK **ppt;
unsigned 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) ||
PAX_IS_HARDLINK(arcn->type))
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 a 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);
}
}
}
/*
* 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 from
* this table, fragmentation of the scratch file is never a 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 = calloc(F_TAB_SZ, sizeof(FTM *))) == NULL) {
paxwarn(1, "%s for %s", "Out of memory",
"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;
unsigned 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 %s on %s",
"seek", "file time table");
return (-1);
}
if (read(ffd, ckname, namelen) != namelen) {
syswarn(1, errno, "Failed %s on %s",
"read", "file time table");
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 (st_timecmp(m, &arcn->sb, &pt->sb, >)) {
/*
* file is newer
*/
st_timecpy(m, &pt->sb, &arcn->sb);
return(0);
}
/*
* file is older
*/
return(1);
}
}
/*
* not in table, add it
*/
if ((pt = 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, 0, SEEK_END)) >= 0) {
if (write(ffd, arcn->name, namelen) == namelen) {
st_timecpy(m, &pt->sb, &arcn->sb);
pt->namelen = namelen;
pt->fow = ftab[indx];
ftab[indx] = pt;
return(0);
}
syswarn(1, errno, "Failed %s on %s",
"write", "file time table");
} else
syswarn(1, errno, "Failed %s on %s",
"seek", "file time table");
} else
paxwarn(1, "%s for %s", "Out of memory", "file time table");
if (pt != NULL)
free(pt);
return(-1);
}
/*
* escaping (absolute or w/"..") symlink table routines
*
* By default, an archive shouldn't be able extract to outside of the
* current directory. What should we do if the archive contains a symlink
* whose value is either absolute or contains ".." components? What we'll
* do is initially create the path as an empty file (to block attempts to
* reference _through_ it) and instead record its path and desired
* final value and mode. Then once all the other archive
* members are created (but before the pass to set timestamps on
* directories) we'll process those records, replacing the placeholder with
* the correct symlink and setting them to the correct mode, owner, group,
* and timestamps.
*
* Note: we also need to handle hardlinks to symlinks (barf) as well as
* hardlinks whose target is replaced by a later entry in the archive (barf^2).
*
* So we track things by dev+ino of the placeholder file, associating with
* that the value and mode of the final symlink and a list of paths that
* should all be hardlinks of that. We'll 'store' the symlink's desired
* timestamps, owner, and group by setting them on the placeholder file.
*
* The operations are:
* a) create an escaping symlink: create the placeholder file and add an entry
* for the new link
* b) create a hardlink: do the link. If the target turns out to be a
* zero-length file whose dev+ino are in the symlink table, then add this
* path to the list of names for that link
* c) perform deferred processing: for each entry, check each associated path:
* if it's a zero-length file with the correct dev+ino then recreate it as
* the specified symlink or hardlink to the first such
*/
struct slpath {
char *sp_path;
struct slpath *sp_next;
};
struct slinode {
ino_t sli_ino;
char *sli_value;
struct slpath sli_paths;
struct slinode *sli_fow; /* hash table chain */
dev_t sli_dev;
mode_t sli_mode;
};
static struct slinode **slitab = NULL;
/*
* sltab_start()
* create the hash table
* Return:
* 0 if the table and file was created ok, -1 otherwise
*/
int
sltab_start(void)
{
if ((slitab = calloc(SL_TAB_SZ, sizeof *slitab)) == NULL) {
syswarn(1, errno, "symlink table");
return(-1);
}
return(0);
}
/*
* sltab_add_sym()
* Create the placeholder and tracking info for an escaping symlink.
* Return:
* 0 on success, -1 otherwise
*/
int
sltab_add_sym(const char *path0, const char *value0, mode_t mode)
{
struct stat sb;
struct slinode *s;
struct slpath *p;
char *path, *value;
unsigned int indx;
int fd;
/* create the placeholder */
fd = binopen3(BO_CLEXEC, path0, O_WRONLY | O_CREAT | O_EXCL, 0600);
if (fd == -1)
return (-1);
if (fstat(fd, &sb) == -1) {
unlink(path0);
close(fd);
return (-1);
}
close(fd);
if (havechd && *path0 != '/') {
if ((path = xrealpath(path0)) == NULL) {
syswarn(1, errno, "Cannot canonicalise %s", path0);
unlink(path0);
return (-1);
}
} else if ((path = strdup(path0)) == NULL) {
syswarn(1, errno, "%s %s", "deferred symlink", "path");
unlink(path0);
return (-1);
}
if ((value = strdup(value0)) == NULL) {
syswarn(1, errno, "%s value", "deferred symlink");
unlink(path);
free(path);
return (-1);
}
/* now check the hash table for conflicting entry */
indx = (sb.st_ino ^ sb.st_dev) % SL_TAB_SZ;
for (s = slitab[indx]; s != NULL; s = s->sli_fow) {
if (s->sli_ino != sb.st_ino || s->sli_dev != sb.st_dev)
continue;
/*
* One of our placeholders got removed behind our back and
* we've reused the inode. Weird, but clean up the mess.
*/
free(s->sli_value);
free(s->sli_paths.sp_path);
p = s->sli_paths.sp_next;
while (p != NULL) {
struct slpath *next_p = p->sp_next;
free(p->sp_path);
free(p);
p = next_p;
}
goto set_value;
}
/* Normal case: create a new node */
if ((s = malloc(sizeof *s)) == NULL) {
syswarn(1, errno, "deferred symlink");
unlink(path);
free(path);
free(value);
return (-1);
}
s->sli_ino = sb.st_ino;
s->sli_dev = sb.st_dev;
s->sli_fow = slitab[indx];
slitab[indx] = s;
set_value:
s->sli_paths.sp_path = path;
s->sli_paths.sp_next = NULL;
s->sli_value = value;
s->sli_mode = mode;
return (0);
}
/*
* sltab_add_link()
* A hardlink was created; if it looks like a placeholder, handle the
* tracking.
* Return:
* 0 if things are ok, -1 if something went wrong
*/
int
sltab_add_link(const char *path, const struct stat *sb)
{
struct slinode *s;
struct slpath *p;
unsigned int indx;
if (!S_ISREG(sb->st_mode) || sb->st_size != 0)
return (1);
/* find the hash table entry for this hardlink */
indx = (sb->st_ino ^ sb->st_dev) % SL_TAB_SZ;
for (s = slitab[indx]; s != NULL; s = s->sli_fow) {
if (s->sli_ino != sb->st_ino || s->sli_dev != sb->st_dev)
continue;
if ((p = malloc(sizeof *p)) == NULL) {
syswarn(1, errno, "%s hardlink", "deferred symlink");
return (-1);
}
if (havechd && *path != '/') {
if ((p->sp_path = xrealpath(path)) == NULL) {
syswarn(1, errno, "Cannot canonicalise %s",
path);
free(p);
return (-1);
}
} else if ((p->sp_path = strdup(path)) == NULL) {
syswarn(1, errno, "%s hardlink path", "deferred symlink");
free(p);
return (-1);
}
/* link it in */
p->sp_next = s->sli_paths.sp_next;
s->sli_paths.sp_next = p;
return (0);
}
/* not found */
return (1);
}
static int
sltab_process_one(struct slinode *s, struct slpath *p, const char *first,
int in_sig)
{
struct stat sb;
char *path = p->sp_path;
mode_t mode;
int err;
/*
* is it the expected placeholder? This can fail legimately
* if the archive overwrote the link with another, later entry,
* so don't warn.
*/
if (stat(path, &sb) != 0 || !S_ISREG(sb.st_mode) || sb.st_size != 0 ||
sb.st_ino != s->sli_ino || sb.st_dev != s->sli_dev)
return (0);
if (unlink(path) && errno != ENOENT) {
if (!in_sig)
syswarn(1, errno, "%s removal", "deferred symlink");
return (0);
}
err = 0;
if (first != NULL) {
#if HAVE_LINKAT
/* add another hardlink to the existing symlink */
if (linkat(AT_FDCWD, first, AT_FDCWD, path, 0) == 0)
return (0);
/*
* Couldn't hardlink the symlink for some reason, so we'll
* try creating it as its own symlink, but save the error
* for reporting if that fails.
*/
err = errno;
#else
err = EOPNOTSUPP;
#endif
}
if (symlink(s->sli_value, path)) {
if (!in_sig) {
const char *qualifier = "";
if (err)
qualifier = " hardlink";
else
err = errno;
syswarn(1, err, "%s%s: %s",
"deferred symlink", qualifier, path);
}
return (0);
}
/* success, so set the id, mode, and times */
mode = s->sli_mode;
if (pids) {
/* if can't set the ids, force the set[ug]id bits off */
if (set_ids(path, sb.st_uid, sb.st_gid, 1))
mode &= ~(SETBITS);
}
if (pmode)
set_pmode(path, mode, 1);
if (patime || pmtime)
set_ftime(path, &sb, 0, 1);
/*
* If we tried to link to first but failed, then this new symlink
* might be a better one to try in the future. Guess from the errno.
*/
if (err == 0 || err == ENOENT || err == EMLINK || err == EOPNOTSUPP)
return (1);
return (0);
}
/*
* sltab_process()
* Do all the delayed process for escape symlinks
*/
void
sltab_process(int in_sig)
{
struct slinode *s;
struct slpath *p;
char *first;
unsigned int indx;
if (slitab == NULL)
return;
/* walk across the entire hash table */
for (indx = 0; indx < SL_TAB_SZ; indx++) {
while ((s = slitab[indx]) != NULL) {
/* pop this entry */
slitab[indx] = s->sli_fow;
first = NULL;
p = &s->sli_paths;
while (1) {
struct slpath *next_p;
if (sltab_process_one(s, p, first, in_sig)) {
if (!in_sig)
free(first);
first = p->sp_path;
} else if (!in_sig)
free(p->sp_path);
if ((next_p = p->sp_next) == NULL)
break;
*p = *next_p;
if (!in_sig)
free(next_p);
}
if (!in_sig) {
free(first);
free(s->sli_value);
free(s);
}
}
}
if (!in_sig)
free(slitab);
slitab = NULL;
}
/*
* 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).
*/