/*- * SPDX-License-Identifier: BSD-3-Clause * * 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/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 "pax.h" #include "extern.h" static void wr_archive(ARCHD *, int is_app); static int get_arc(void); static int next_head(ARCHD *); /* * 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 (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) && ((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 is not append, and there are no files, we do not 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); }
