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Diffstat (limited to 'bin/pax/ar_subs.c')
| -rw-r--r-- | bin/pax/ar_subs.c | 1277 |
1 files changed, 1277 insertions, 0 deletions
diff --git a/bin/pax/ar_subs.c b/bin/pax/ar_subs.c new file mode 100644 index 0000000..f0a55ab --- /dev/null +++ b/bin/pax/ar_subs.c @@ -0,0 +1,1277 @@ +/* $OpenBSD: ar_subs.c,v 1.49 2019/06/28 13:34:59 deraadt Exp $ */ +/* $NetBSD: ar_subs.c,v 1.5 1995/03/21 09:07:06 cgd Exp $ */ + +/*- + * 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> +#include <sys/stat.h> +#include <sys/time.h> +#include <err.h> +#include <errno.h> +#include <fcntl.h> +#include <signal.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <time.h> +#include <unistd.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 *); +static int rd_gnu_string(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; + + now = time(NULL); + + /* + * step through the archive until the format says it is done + */ + while (next_head(arcn) == 0) { + if (rd_gnu_string(arcn)) + continue; + + /* + * 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(0); + pat_chk(); +} + +static int +cmp_file_times(int mtime_flag, int ctime_flag, ARCHD *arcn, struct stat *sbp) +{ + struct stat sb; + + if (sbp == NULL) { + if (lstat(arcn->name, &sb) != 0) + return (0); + sbp = &sb; + } + + if (ctime_flag && mtime_flag) + return (timespeccmp(&arcn->sb.st_mtim, &sbp->st_mtim, <=) && + timespeccmp(&arcn->sb.st_ctim, &sbp->st_ctim, <=)); + else if (ctime_flag) + return (timespeccmp(&arcn->sb.st_ctim, &sbp->st_ctim, <=)); + else + return (timespeccmp(&arcn->sb.st_mtim, &sbp->st_mtim, <=)); +} + +/* + * 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; + int fd; + time_t now; + + sltab_start(); + + 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) { + if (rd_gnu_string(arcn)) + continue; + + /* + * 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 (no + * 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) && + cmp_file_times(uflag, Dflag, arcn, NULL)) { + (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) && + cmp_file_times(Yflag, Zflag, arcn, NULL)) { + (void)rd_skip(arcn->skip + arcn->pad); + continue; + } + + if (vflag) { + if (vflag > 1) + ls_list(arcn, now, listf); + else { + (void)safe_print(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 (!PAX_IS_REG(arcn->type)) { + /* + * 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 (PAX_IS_HARDLINK(arcn->type)) + 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; + } + goto popd; + } + /* + * 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); + goto popd; + } + /* + * extract the file from the archive and skip over padding and + * any unprocessed data + */ + res = rd_wrfile(arcn, fd, &cnt); + file_close(arcn, fd); + if (vflag && vfpart) { + (void)putc('\n', listf); + vfpart = 0; + } + if (!res) + (void)rd_skip(cnt + arcn->pad); + +popd: + /* + * 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(0); + sltab_process(0); + proc_dir(0); + 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; + + /* + * if this is not append, and there are no files, we do not write a + * trailer + */ + wr_one = is_app; + + /* + * start up the file traversal code and format specific write + */ + if (ftree_start() < 0) { + if (is_app) + goto trailer; + return; + } else if (((*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; + + 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) + 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) { + ftree_skipped_newer(arcn); + 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 (PAX_IS_REG(arcn->type) || (arcn->type == PAX_HRG)) { + /* + * 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)safe_print(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 = wr_rdfile(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; + } + +trailer: + /* + * 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(0); + if (tflag) + proc_dir(0); + 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; + size_t dlen; + size_t drem; + int fdsrc = -1; + struct stat sb; + ARCHD archd; + char dirbuf[PAXPATHLEN+1]; + + sltab_start(); + + 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 = strlcpy(dirbuf, dirptr, sizeof(dirbuf)); + if (dlen >= sizeof(dirbuf) || + (dlen == sizeof(dirbuf) - 1 && dirbuf[dlen - 1] != '/')) { + paxwarn(1, "directory name is too long %s", dirptr); + return; + } + dest_pt = dirbuf + dlen; + if (*(dest_pt-1) != '/') { + *dest_pt++ = '/'; + *dest_pt = '\0'; + ++dlen; + } + drem = PAXPATHLEN - dlen; + + if (stat(dirptr, &sb) == -1) { + 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) + 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 (strlcpy(dest_pt, arcn->name + (*arcn->name == '/'), + drem + 1) > drem) { + paxwarn(1, "Destination pathname too long %s", + arcn->name); + continue; + } + + /* + * if existing file is same age or newer skip + */ + res = lstat(dirbuf, &sb); + *dest_pt = '\0'; + + if (res == 0) { + ftree_skipped_newer(arcn); + if (cmp_file_times(uflag, Dflag, arcn, &sb)) + 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) && + cmp_file_times(Yflag, Zflag, arcn, NULL)) + continue; + + if (vflag) { + (void)safe_print(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 (!PAX_IS_REG(arcn->type)) { + /* + * create a link or special file + */ + if (PAX_IS_HARDLINK(arcn->type)) + 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(0); + sltab_process(0); + proc_dir(0); + 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)(arcn,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 + * the header. NOTE: the parameters are different than trailer routines + * which encode trailers outside of the header! + */ + if (frmt->inhead && ((*frmt->trail)(arcn,NULL,0,NULL) == 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]].name != NULL && 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 == NULL || + (*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); +} + +/* + * rd_gnu_string() + * Read the file contents into an allocated string if it is a GNU tar + * long link/file. + * Return: + * 1 if gnu string read, 0 otherwise + */ + +static int +rd_gnu_string(ARCHD *arcn) +{ + char **strp; + + switch (arcn->type) { + case PAX_GLF: + strp = &gnu_name_string; + break; + case PAX_GLL: + strp = &gnu_link_string; + break; + default: + strp = NULL; + break; + } + if (!strp) + return 0; + /* + * we need to read, to get the real filename + */ + if (*strp) + err(1, "WARNING! Major Internal Error! GNU hack Failing!"); + *strp = malloc(arcn->sb.st_size + 1); + if (*strp == NULL) { + paxwarn(1, "Out of memory"); + (void)rd_skip(arcn->skip + arcn->pad); + } else if (rd_wrbuf(*strp, arcn->sb.st_size) < arcn->sb.st_size) { + free(*strp); + *strp = NULL; + } else { + (*strp)[arcn->sb.st_size] = '\0'; + (void)rd_skip(arcn->pad); + } + return 1; +} |