| Current Path : /usr/src/bin/pax/ |
FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //usr/src/bin/pax/ar_subs.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[] = "@(#)ar_subs.c 8.2 (Berkeley) 4/18/94";
#endif
#endif /* not lint */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/bin/pax/ar_subs.c 222177 2011-05-22 14:03:38Z uqs $");
#include <sys/types.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <signal.h>
#include <string.h>
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include "pax.h"
#include "extern.h"
static void wr_archive(ARCHD *, int is_app);
static int get_arc(void);
static int next_head(ARCHD *);
extern sigset_t s_mask;
/*
* Routines which control the overall operation modes of pax as specified by
* the user: list, append, read ...
*/
static char hdbuf[BLKMULT]; /* space for archive header on read */
u_long flcnt; /* number of files processed */
/*
* list()
* list the contents of an archive which match user supplied pattern(s)
* (no pattern matches all).
*/
void
list(void)
{
ARCHD *arcn;
int res;
ARCHD archd;
time_t now;
arcn = &archd;
/*
* figure out archive type; pass any format specific options to the
* archive option processing routine; call the format init routine. We
* also save current time for ls_list() so we do not make a system
* call for each file we need to print. If verbose (vflag) start up
* the name and group caches.
*/
if ((get_arc() < 0) || ((*frmt->options)() < 0) ||
((*frmt->st_rd)() < 0))
return;
if (vflag && ((uidtb_start() < 0) || (gidtb_start() < 0)))
return;
now = time(NULL);
/*
* step through the archive until the format says it is done
*/
while (next_head(arcn) == 0) {
/*
* check for pattern, and user specified options match.
* When all patterns are matched we are done.
*/
if ((res = pat_match(arcn)) < 0)
break;
if ((res == 0) && (sel_chk(arcn) == 0)) {
/*
* pattern resulted in a selected file
*/
if (pat_sel(arcn) < 0)
break;
/*
* modify the name as requested by the user if name
* survives modification, do a listing of the file
*/
if ((res = mod_name(arcn)) < 0)
break;
if (res == 0)
ls_list(arcn, now, stdout);
}
/*
* skip to next archive format header using values calculated
* by the format header read routine
*/
if (rd_skip(arcn->skip + arcn->pad) == 1)
break;
}
/*
* all done, let format have a chance to cleanup, and make sure that
* the patterns supplied by the user were all matched
*/
(void)(*frmt->end_rd)();
(void)sigprocmask(SIG_BLOCK, &s_mask, NULL);
ar_close();
pat_chk();
}
/*
* extract()
* extract the member(s) of an archive as specified by user supplied
* pattern(s) (no patterns extracts all members)
*/
void
extract(void)
{
ARCHD *arcn;
int res;
off_t cnt;
ARCHD archd;
struct stat sb;
int fd;
time_t now;
arcn = &archd;
/*
* figure out archive type; pass any format specific options to the
* archive option processing routine; call the format init routine;
* start up the directory modification time and access mode database
*/
if ((get_arc() < 0) || ((*frmt->options)() < 0) ||
((*frmt->st_rd)() < 0) || (dir_start() < 0))
return;
/*
* When we are doing interactive rename, we store the mapping of names
* so we can fix up hard links files later in the archive.
*/
if (iflag && (name_start() < 0))
return;
now = time(NULL);
/*
* step through each entry on the archive until the format read routine
* says it is done
*/
while (next_head(arcn) == 0) {
/*
* check for pattern, and user specified options match. When
* all the patterns are matched we are done
*/
if ((res = pat_match(arcn)) < 0)
break;
if ((res > 0) || (sel_chk(arcn) != 0)) {
/*
* file is not selected. skip past any file data and
* padding and go back for the next archive member
*/
(void)rd_skip(arcn->skip + arcn->pad);
continue;
}
/*
* with -u or -D only extract when the archive member is newer
* than the file with the same name in the file system (nos
* test of being the same type is required).
* NOTE: this test is done BEFORE name modifications as
* specified by pax. this operation can be confusing to the
* user who might expect the test to be done on an existing
* file AFTER the name mod. In honesty the pax spec is probably
* flawed in this respect.
*/
if ((uflag || Dflag) && ((lstat(arcn->name, &sb) == 0))) {
if (uflag && Dflag) {
if ((arcn->sb.st_mtime <= sb.st_mtime) &&
(arcn->sb.st_ctime <= sb.st_ctime)) {
(void)rd_skip(arcn->skip + arcn->pad);
continue;
}
} else if (Dflag) {
if (arcn->sb.st_ctime <= sb.st_ctime) {
(void)rd_skip(arcn->skip + arcn->pad);
continue;
}
} else if (arcn->sb.st_mtime <= sb.st_mtime) {
(void)rd_skip(arcn->skip + arcn->pad);
continue;
}
}
/*
* this archive member is now been selected. modify the name.
*/
if ((pat_sel(arcn) < 0) || ((res = mod_name(arcn)) < 0))
break;
if (res > 0) {
/*
* a bad name mod, skip and purge name from link table
*/
purg_lnk(arcn);
(void)rd_skip(arcn->skip + arcn->pad);
continue;
}
/*
* Non standard -Y and -Z flag. When the existing file is
* same age or newer skip
*/
if ((Yflag || Zflag) && ((lstat(arcn->name, &sb) == 0))) {
if (Yflag && Zflag) {
if ((arcn->sb.st_mtime <= sb.st_mtime) &&
(arcn->sb.st_ctime <= sb.st_ctime)) {
(void)rd_skip(arcn->skip + arcn->pad);
continue;
}
} else if (Yflag) {
if (arcn->sb.st_ctime <= sb.st_ctime) {
(void)rd_skip(arcn->skip + arcn->pad);
continue;
}
} else if (arcn->sb.st_mtime <= sb.st_mtime) {
(void)rd_skip(arcn->skip + arcn->pad);
continue;
}
}
if (vflag) {
if (vflag > 1)
ls_list(arcn, now, listf);
else {
(void)fputs(arcn->name, listf);
vfpart = 1;
}
}
/*
* if required, chdir around.
*/
if ((arcn->pat != NULL) && (arcn->pat->chdname != NULL))
if (chdir(arcn->pat->chdname) != 0)
syswarn(1, errno, "Cannot chdir to %s",
arcn->pat->chdname);
/*
* all ok, extract this member based on type
*/
if ((arcn->type != PAX_REG) && (arcn->type != PAX_CTG)) {
/*
* process archive members that are not regular files.
* throw out padding and any data that might follow the
* header (as determined by the format).
*/
if ((arcn->type == PAX_HLK) || (arcn->type == PAX_HRG))
res = lnk_creat(arcn);
else
res = node_creat(arcn);
(void)rd_skip(arcn->skip + arcn->pad);
if (res < 0)
purg_lnk(arcn);
if (vflag && vfpart) {
(void)putc('\n', listf);
vfpart = 0;
}
continue;
}
/*
* we have a file with data here. If we can not create it, skip
* over the data and purge the name from hard link table
*/
if ((fd = file_creat(arcn)) < 0) {
(void)rd_skip(arcn->skip + arcn->pad);
purg_lnk(arcn);
continue;
}
/*
* extract the file from the archive and skip over padding and
* any unprocessed data
*/
res = (*frmt->rd_data)(arcn, fd, &cnt);
file_close(arcn, fd);
if (vflag && vfpart) {
(void)putc('\n', listf);
vfpart = 0;
}
if (!res)
(void)rd_skip(cnt + arcn->pad);
/*
* if required, chdir around.
*/
if ((arcn->pat != NULL) && (arcn->pat->chdname != NULL))
if (fchdir(cwdfd) != 0)
syswarn(1, errno,
"Can't fchdir to starting directory");
}
/*
* all done, restore directory modes and times as required; make sure
* all patterns supplied by the user were matched; block off signals
* to avoid chance for multiple entry into the cleanup code.
*/
(void)(*frmt->end_rd)();
(void)sigprocmask(SIG_BLOCK, &s_mask, NULL);
ar_close();
proc_dir();
pat_chk();
}
/*
* wr_archive()
* Write an archive. used in both creating a new archive and appends on
* previously written archive.
*/
static void
wr_archive(ARCHD *arcn, int is_app)
{
int res;
int hlk;
int wr_one;
off_t cnt;
int (*wrf)(ARCHD *);
int fd = -1;
time_t now;
/*
* if this format supports hard link storage, start up the database
* that detects them.
*/
if (((hlk = frmt->hlk) == 1) && (lnk_start() < 0))
return;
/*
* start up the file traversal code and format specific write
*/
if ((ftree_start() < 0) || ((*frmt->st_wr)() < 0))
return;
wrf = frmt->wr;
/*
* When we are doing interactive rename, we store the mapping of names
* so we can fix up hard links files later in the archive.
*/
if (iflag && (name_start() < 0))
return;
/*
* if this not append, and there are no files, we do no write a trailer
*/
wr_one = is_app;
now = time(NULL);
/*
* while there are files to archive, process them one at at time
*/
while (next_file(arcn) == 0) {
/*
* check if this file meets user specified options match.
*/
if (sel_chk(arcn) != 0) {
ftree_notsel();
continue;
}
fd = -1;
if (uflag) {
/*
* only archive if this file is newer than a file with
* the same name that is already stored on the archive
*/
if ((res = chk_ftime(arcn)) < 0)
break;
if (res > 0)
continue;
}
/*
* this file is considered selected now. see if this is a hard
* link to a file already stored
*/
ftree_sel(arcn);
if (hlk && (chk_lnk(arcn) < 0))
break;
if ((arcn->type == PAX_REG) || (arcn->type == PAX_HRG) ||
(arcn->type == PAX_CTG)) {
/*
* we will have to read this file. by opening it now we
* can avoid writing a header to the archive for a file
* we were later unable to read (we also purge it from
* the link table).
*/
if ((fd = open(arcn->org_name, O_RDONLY, 0)) < 0) {
syswarn(1,errno, "Unable to open %s to read",
arcn->org_name);
purg_lnk(arcn);
continue;
}
}
/*
* Now modify the name as requested by the user
*/
if ((res = mod_name(arcn)) < 0) {
/*
* name modification says to skip this file, close the
* file and purge link table entry
*/
rdfile_close(arcn, &fd);
purg_lnk(arcn);
break;
}
if ((res > 0) || (docrc && (set_crc(arcn, fd) < 0))) {
/*
* unable to obtain the crc we need, close the file,
* purge link table entry
*/
rdfile_close(arcn, &fd);
purg_lnk(arcn);
continue;
}
if (vflag) {
if (vflag > 1)
ls_list(arcn, now, listf);
else {
(void)fputs(arcn->name, listf);
vfpart = 1;
}
}
++flcnt;
/*
* looks safe to store the file, have the format specific
* routine write routine store the file header on the archive
*/
if ((res = (*wrf)(arcn)) < 0) {
rdfile_close(arcn, &fd);
break;
}
wr_one = 1;
if (res > 0) {
/*
* format write says no file data needs to be stored
* so we are done messing with this file
*/
if (vflag && vfpart) {
(void)putc('\n', listf);
vfpart = 0;
}
rdfile_close(arcn, &fd);
continue;
}
/*
* Add file data to the archive, quit on write error. if we
* cannot write the entire file contents to the archive we
* must pad the archive to replace the missing file data
* (otherwise during an extract the file header for the file
* which FOLLOWS this one will not be where we expect it to
* be).
*/
res = (*frmt->wr_data)(arcn, fd, &cnt);
rdfile_close(arcn, &fd);
if (vflag && vfpart) {
(void)putc('\n', listf);
vfpart = 0;
}
if (res < 0)
break;
/*
* pad as required, cnt is number of bytes not written
*/
if (((cnt > 0) && (wr_skip(cnt) < 0)) ||
((arcn->pad > 0) && (wr_skip(arcn->pad) < 0)))
break;
}
/*
* tell format to write trailer; pad to block boundary; reset directory
* mode/access times, and check if all patterns supplied by the user
* were matched. block off signals to avoid chance for multiple entry
* into the cleanup code
*/
if (wr_one) {
(*frmt->end_wr)();
wr_fin();
}
(void)sigprocmask(SIG_BLOCK, &s_mask, NULL);
ar_close();
if (tflag)
proc_dir();
ftree_chk();
}
/*
* append()
* Add file to previously written archive. Archive format specified by the
* user must agree with archive. The archive is read first to collect
* modification times (if -u) and locate the archive trailer. The archive
* is positioned in front of the record with the trailer and wr_archive()
* is called to add the new members.
* PAX IMPLEMENTATION DETAIL NOTE:
* -u is implemented by adding the new members to the end of the archive.
* Care is taken so that these do not end up as links to the older
* version of the same file already stored in the archive. It is expected
* when extraction occurs these newer versions will over-write the older
* ones stored "earlier" in the archive (this may be a bad assumption as
* it depends on the implementation of the program doing the extraction).
* It is really difficult to splice in members without either re-writing
* the entire archive (from the point were the old version was), or having
* assistance of the format specification in terms of a special update
* header that invalidates a previous archive record. The POSIX spec left
* the method used to implement -u unspecified. This pax is able to
* over write existing files that it creates.
*/
void
append(void)
{
ARCHD *arcn;
int res;
ARCHD archd;
FSUB *orgfrmt;
int udev;
off_t tlen;
arcn = &archd;
orgfrmt = frmt;
/*
* Do not allow an append operation if the actual archive is of a
* different format than the user specified format.
*/
if (get_arc() < 0)
return;
if ((orgfrmt != NULL) && (orgfrmt != frmt)) {
paxwarn(1, "Cannot mix current archive format %s with %s",
frmt->name, orgfrmt->name);
return;
}
/*
* pass the format any options and start up format
*/
if (((*frmt->options)() < 0) || ((*frmt->st_rd)() < 0))
return;
/*
* if we only are adding members that are newer, we need to save the
* mod times for all files we see.
*/
if (uflag && (ftime_start() < 0))
return;
/*
* some archive formats encode hard links by recording the device and
* file serial number (inode) but copy the file anyway (multiple times)
* to the archive. When we append, we run the risk that newly added
* files may have the same device and inode numbers as those recorded
* on the archive but during a previous run. If this happens, when the
* archive is extracted we get INCORRECT hard links. We avoid this by
* remapping the device numbers so that newly added files will never
* use the same device number as one found on the archive. remapping
* allows new members to safely have links among themselves. remapping
* also avoids problems with file inode (serial number) truncations
* when the inode number is larger than storage space in the archive
* header. See the remap routines for more details.
*/
if ((udev = frmt->udev) && (dev_start() < 0))
return;
/*
* reading the archive may take a long time. If verbose tell the user
*/
if (vflag) {
(void)fprintf(listf,
"%s: Reading archive to position at the end...", argv0);
vfpart = 1;
}
/*
* step through the archive until the format says it is done
*/
while (next_head(arcn) == 0) {
/*
* check if this file meets user specified options.
*/
if (sel_chk(arcn) != 0) {
if (rd_skip(arcn->skip + arcn->pad) == 1)
break;
continue;
}
if (uflag) {
/*
* see if this is the newest version of this file has
* already been seen, if so skip.
*/
if ((res = chk_ftime(arcn)) < 0)
break;
if (res > 0) {
if (rd_skip(arcn->skip + arcn->pad) == 1)
break;
continue;
}
}
/*
* Store this device number. Device numbers seen during the
* read phase of append will cause newly appended files with a
* device number seen in the old part of the archive to be
* remapped to an unused device number.
*/
if ((udev && (add_dev(arcn) < 0)) ||
(rd_skip(arcn->skip + arcn->pad) == 1))
break;
}
/*
* done, finish up read and get the number of bytes to back up so we
* can add new members. The format might have used the hard link table,
* purge it.
*/
tlen = (*frmt->end_rd)();
lnk_end();
/*
* try to position for write, if this fails quit. if any error occurs,
* we will refuse to write
*/
if (appnd_start(tlen) < 0)
return;
/*
* tell the user we are done reading.
*/
if (vflag && vfpart) {
(void)fputs("done.\n", listf);
vfpart = 0;
}
/*
* go to the writing phase to add the new members
*/
wr_archive(arcn, 1);
}
/*
* archive()
* write a new archive
*/
void
archive(void)
{
ARCHD archd;
/*
* if we only are adding members that are newer, we need to save the
* mod times for all files; set up for writing; pass the format any
* options write the archive
*/
if ((uflag && (ftime_start() < 0)) || (wr_start() < 0))
return;
if ((*frmt->options)() < 0)
return;
wr_archive(&archd, 0);
}
/*
* copy()
* copy files from one part of the file system to another. this does not
* use any archive storage. The EFFECT OF THE COPY IS THE SAME as if an
* archive was written and then extracted in the destination directory
* (except the files are forced to be under the destination directory).
*/
void
copy(void)
{
ARCHD *arcn;
int res;
int fddest;
char *dest_pt;
int dlen;
int drem;
int fdsrc = -1;
struct stat sb;
ARCHD archd;
char dirbuf[PAXPATHLEN+1];
arcn = &archd;
/*
* set up the destination dir path and make sure it is a directory. We
* make sure we have a trailing / on the destination
*/
dlen = l_strncpy(dirbuf, dirptr, sizeof(dirbuf) - 1);
dest_pt = dirbuf + dlen;
if (*(dest_pt-1) != '/') {
*dest_pt++ = '/';
++dlen;
}
*dest_pt = '\0';
drem = PAXPATHLEN - dlen;
if (stat(dirptr, &sb) < 0) {
syswarn(1, errno, "Cannot access destination directory %s",
dirptr);
return;
}
if (!S_ISDIR(sb.st_mode)) {
paxwarn(1, "Destination is not a directory %s", dirptr);
return;
}
/*
* start up the hard link table; file traversal routines and the
* modification time and access mode database
*/
if ((lnk_start() < 0) || (ftree_start() < 0) || (dir_start() < 0))
return;
/*
* When we are doing interactive rename, we store the mapping of names
* so we can fix up hard links files later in the archive.
*/
if (iflag && (name_start() < 0))
return;
/*
* set up to cp file trees
*/
cp_start();
/*
* while there are files to archive, process them
*/
while (next_file(arcn) == 0) {
fdsrc = -1;
/*
* check if this file meets user specified options
*/
if (sel_chk(arcn) != 0) {
ftree_notsel();
continue;
}
/*
* if there is already a file in the destination directory with
* the same name and it is newer, skip the one stored on the
* archive.
* NOTE: this test is done BEFORE name modifications as
* specified by pax. this can be confusing to the user who
* might expect the test to be done on an existing file AFTER
* the name mod. In honesty the pax spec is probably flawed in
* this respect
*/
if (uflag || Dflag) {
/*
* create the destination name
*/
if (*(arcn->name) == '/')
res = 1;
else
res = 0;
if ((arcn->nlen - res) > drem) {
paxwarn(1, "Destination pathname too long %s",
arcn->name);
continue;
}
(void)strncpy(dest_pt, arcn->name + res, drem);
dirbuf[PAXPATHLEN] = '\0';
/*
* if existing file is same age or newer skip
*/
res = lstat(dirbuf, &sb);
*dest_pt = '\0';
if (res == 0) {
if (uflag && Dflag) {
if ((arcn->sb.st_mtime<=sb.st_mtime) &&
(arcn->sb.st_ctime<=sb.st_ctime))
continue;
} else if (Dflag) {
if (arcn->sb.st_ctime <= sb.st_ctime)
continue;
} else if (arcn->sb.st_mtime <= sb.st_mtime)
continue;
}
}
/*
* this file is considered selected. See if this is a hard link
* to a previous file; modify the name as requested by the
* user; set the final destination.
*/
ftree_sel(arcn);
if ((chk_lnk(arcn) < 0) || ((res = mod_name(arcn)) < 0))
break;
if ((res > 0) || (set_dest(arcn, dirbuf, dlen) < 0)) {
/*
* skip file, purge from link table
*/
purg_lnk(arcn);
continue;
}
/*
* Non standard -Y and -Z flag. When the existing file is
* same age or newer skip
*/
if ((Yflag || Zflag) && ((lstat(arcn->name, &sb) == 0))) {
if (Yflag && Zflag) {
if ((arcn->sb.st_mtime <= sb.st_mtime) &&
(arcn->sb.st_ctime <= sb.st_ctime))
continue;
} else if (Yflag) {
if (arcn->sb.st_ctime <= sb.st_ctime)
continue;
} else if (arcn->sb.st_mtime <= sb.st_mtime)
continue;
}
if (vflag) {
(void)fputs(arcn->name, listf);
vfpart = 1;
}
++flcnt;
/*
* try to create a hard link to the src file if requested
* but make sure we are not trying to overwrite ourselves.
*/
if (lflag)
res = cross_lnk(arcn);
else
res = chk_same(arcn);
if (res <= 0) {
if (vflag && vfpart) {
(void)putc('\n', listf);
vfpart = 0;
}
continue;
}
/*
* have to create a new file
*/
if ((arcn->type != PAX_REG) && (arcn->type != PAX_CTG)) {
/*
* create a link or special file
*/
if ((arcn->type == PAX_HLK) || (arcn->type == PAX_HRG))
res = lnk_creat(arcn);
else
res = node_creat(arcn);
if (res < 0)
purg_lnk(arcn);
if (vflag && vfpart) {
(void)putc('\n', listf);
vfpart = 0;
}
continue;
}
/*
* have to copy a regular file to the destination directory.
* first open source file and then create the destination file
*/
if ((fdsrc = open(arcn->org_name, O_RDONLY, 0)) < 0) {
syswarn(1, errno, "Unable to open %s to read",
arcn->org_name);
purg_lnk(arcn);
continue;
}
if ((fddest = file_creat(arcn)) < 0) {
rdfile_close(arcn, &fdsrc);
purg_lnk(arcn);
continue;
}
/*
* copy source file data to the destination file
*/
cp_file(arcn, fdsrc, fddest);
file_close(arcn, fddest);
rdfile_close(arcn, &fdsrc);
if (vflag && vfpart) {
(void)putc('\n', listf);
vfpart = 0;
}
}
/*
* restore directory modes and times as required; make sure all
* patterns were selected block off signals to avoid chance for
* multiple entry into the cleanup code.
*/
(void)sigprocmask(SIG_BLOCK, &s_mask, NULL);
ar_close();
proc_dir();
ftree_chk();
}
/*
* next_head()
* try to find a valid header in the archive. Uses format specific
* routines to extract the header and id the trailer. Trailers may be
* located within a valid header or in an invalid header (the location
* is format specific. The inhead field from the option table tells us
* where to look for the trailer).
* We keep reading (and resyncing) until we get enough contiguous data
* to check for a header. If we cannot find one, we shift by a byte
* add a new byte from the archive to the end of the buffer and try again.
* If we get a read error, we throw out what we have (as we must have
* contiguous data) and start over again.
* ASSUMED: headers fit within a BLKMULT header.
* Return:
* 0 if we got a header, -1 if we are unable to ever find another one
* (we reached the end of input, or we reached the limit on retries. see
* the specs for rd_wrbuf() for more details)
*/
static int
next_head(ARCHD *arcn)
{
int ret;
char *hdend;
int res;
int shftsz;
int hsz;
int in_resync = 0; /* set when we are in resync mode */
int cnt = 0; /* counter for trailer function */
int first = 1; /* on 1st read, EOF isn't premature. */
/*
* set up initial conditions, we want a whole frmt->hsz block as we
* have no data yet.
*/
res = hsz = frmt->hsz;
hdend = hdbuf;
shftsz = hsz - 1;
for(;;) {
/*
* keep looping until we get a contiguous FULL buffer
* (frmt->hsz is the proper size)
*/
for (;;) {
if ((ret = rd_wrbuf(hdend, res)) == res)
break;
/*
* If we read 0 bytes (EOF) from an archive when we
* expect to find a header, we have stepped upon
* an archive without the customary block of zeroes
* end marker. It's just stupid to error out on
* them, so exit gracefully.
*/
if (first && ret == 0)
return(-1);
first = 0;
/*
* some kind of archive read problem, try to resync the
* storage device, better give the user the bad news.
*/
if ((ret == 0) || (rd_sync() < 0)) {
paxwarn(1,"Premature end of file on archive read");
return(-1);
}
if (!in_resync) {
if (act == APPND) {
paxwarn(1,
"Archive I/O error, cannot continue");
return(-1);
}
paxwarn(1,"Archive I/O error. Trying to recover.");
++in_resync;
}
/*
* oh well, throw it all out and start over
*/
res = hsz;
hdend = hdbuf;
}
/*
* ok we have a contiguous buffer of the right size. Call the
* format read routine. If this was not a valid header and this
* format stores trailers outside of the header, call the
* format specific trailer routine to check for a trailer. We
* have to watch out that we do not mis-identify file data or
* block padding as a header or trailer. Format specific
* trailer functions must NOT check for the trailer while we
* are running in resync mode. Some trailer functions may tell
* us that this block cannot contain a valid header either, so
* we then throw out the entire block and start over.
*/
if ((*frmt->rd)(arcn, hdbuf) == 0)
break;
if (!frmt->inhead) {
/*
* this format has trailers outside of valid headers
*/
if ((ret = (*frmt->trail_tar)(hdbuf,in_resync,&cnt)) == 0){
/*
* valid trailer found, drain input as required
*/
ar_drain();
return(-1);
}
if (ret == 1) {
/*
* we are in resync and we were told to throw
* the whole block out because none of the
* bytes in this block can be used to form a
* valid header
*/
res = hsz;
hdend = hdbuf;
continue;
}
}
/*
* Brute force section.
* not a valid header. We may be able to find a header yet. So
* we shift over by one byte, and set up to read one byte at a
* time from the archive and place it at the end of the buffer.
* We will keep moving byte at a time until we find a header or
* get a read error and have to start over.
*/
if (!in_resync) {
if (act == APPND) {
paxwarn(1,"Unable to append, archive header flaw");
return(-1);
}
paxwarn(1,"Invalid header, starting valid header search.");
++in_resync;
}
memmove(hdbuf, hdbuf+1, shftsz);
res = 1;
hdend = hdbuf + shftsz;
}
/*
* ok got a valid header, check for trailer if format encodes it in
* the header.
*/
if (frmt->inhead && ((*frmt->trail_cpio)(arcn) == 0)) {
/*
* valid trailer found, drain input as required
*/
ar_drain();
return(-1);
}
++flcnt;
return(0);
}
/*
* get_arc()
* Figure out what format an archive is. Handles archive with flaws by
* brute force searches for a legal header in any supported format. The
* format id routines have to be careful to NOT mis-identify a format.
* ASSUMED: headers fit within a BLKMULT header.
* Return:
* 0 if archive found -1 otherwise
*/
static int
get_arc(void)
{
int i;
int hdsz = 0;
int res;
int minhd = BLKMULT;
char *hdend;
int notice = 0;
/*
* find the smallest header size in all archive formats and then set up
* to read the archive.
*/
for (i = 0; ford[i] >= 0; ++i) {
if (fsub[ford[i]].hsz < minhd)
minhd = fsub[ford[i]].hsz;
}
if (rd_start() < 0)
return(-1);
res = BLKMULT;
hdsz = 0;
hdend = hdbuf;
for(;;) {
for (;;) {
/*
* fill the buffer with at least the smallest header
*/
i = rd_wrbuf(hdend, res);
if (i > 0)
hdsz += i;
if (hdsz >= minhd)
break;
/*
* if we cannot recover from a read error quit
*/
if ((i == 0) || (rd_sync() < 0))
goto out;
/*
* when we get an error none of the data we already
* have can be used to create a legal header (we just
* got an error in the middle), so we throw it all out
* and refill the buffer with fresh data.
*/
res = BLKMULT;
hdsz = 0;
hdend = hdbuf;
if (!notice) {
if (act == APPND)
return(-1);
paxwarn(1,"Cannot identify format. Searching...");
++notice;
}
}
/*
* we have at least the size of the smallest header in any
* archive format. Look to see if we have a match. The array
* ford[] is used to specify the header id order to reduce the
* chance of incorrectly id'ing a valid header (some formats
* may be subsets of each other and the order would then be
* important).
*/
for (i = 0; ford[i] >= 0; ++i) {
if ((*fsub[ford[i]].id)(hdbuf, hdsz) < 0)
continue;
frmt = &(fsub[ford[i]]);
/*
* yuck, to avoid slow special case code in the extract
* routines, just push this header back as if it was
* not seen. We have left extra space at start of the
* buffer for this purpose. This is a bit ugly, but
* adding all the special case code is far worse.
*/
pback(hdbuf, hdsz);
return(0);
}
/*
* We have a flawed archive, no match. we start searching, but
* we never allow additions to flawed archives
*/
if (!notice) {
if (act == APPND)
return(-1);
paxwarn(1, "Cannot identify format. Searching...");
++notice;
}
/*
* brute force search for a header that we can id.
* we shift through byte at a time. this is slow, but we cannot
* determine the nature of the flaw in the archive in a
* portable manner
*/
if (--hdsz > 0) {
memmove(hdbuf, hdbuf+1, hdsz);
res = BLKMULT - hdsz;
hdend = hdbuf + hdsz;
} else {
res = BLKMULT;
hdend = hdbuf;
hdsz = 0;
}
}
out:
/*
* we cannot find a header, bow, apologize and quit
*/
paxwarn(1, "Sorry, unable to determine archive format.");
return(-1);
}