/* $OpenBSD: tables.c,v 1.55 2023/11/26 16:04:17 espie Exp $ */ /* $NetBSD: tables.c,v 1.4 1995/03/21 09:07:45 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 <errno.h> #include <fcntl.h> #include <limits.h> #include <signal.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include "pax.h" #include "extern.h" static u_int st_hash(const char *, int, int); /* * 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 file system 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 timespec mtim; /* files last modification time */ struct ftm *fow; int namelen; /* file name length */ } 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; u_int16_t mode; /* file mode to restore */ u_int16_t frc_mode; /* do we force mode settings? */ } DIRDATA; static HRDLNK **ltab = NULL; /* hard link table for detecting hard links */ static FTM **ftab = NULL; /* file time table for updating arch */ static NAMT **ntab = NULL; /* interactive rename storage table */ #ifndef NOCPIO static DEVT **dtab = NULL; /* device/inode mapping tables */ #endif 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 */ /* * 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, "Cannot allocate memory for hard link table"); return(-1); } return(0); } /* * chk_lnk() * Looks up entry in hard link hash table. If found, it copies the name * of the file it is linked to (we already saw that file) into ln_name. * lnkcnt is decremented and if goes to 1 the node is deleted from the * database. (We have seen all the links to this file). If not found, * we add the file to the database if it has the potential for having * hard links to other files we may process (it has a link count > 1) * Return: * if found returns 1; if not found returns 0; -1 on error */ int chk_lnk(ARCHD *arcn) { HRDLNK *pt; HRDLNK **ppt; u_int indx; if (ltab == NULL) return(-1); /* * ignore those nodes that cannot have hard links */ if ((arcn->type == PAX_DIR) || (arcn->sb.st_nlink <= 1)) return(0); /* * hash inode number and look for this file */ indx = ((unsigned)arcn->sb.st_ino) % L_TAB_SZ; if ((pt = ltab[indx]) != NULL) { /* * 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, "Hard link table out of memory"); return(-1); } /* * purg_lnk * remove reference for a file that we may have added to the data base as * a potential source for hard links. We ended up not using the file, so * we do not want to accidently point another file at it later on. */ void purg_lnk(ARCHD *arcn) { HRDLNK *pt; HRDLNK **ppt; u_int indx; if (ltab == NULL) return; /* * do not bother to look if it could not be in the database */ if ((arcn->sb.st_nlink <= 1) || (arcn->type == PAX_DIR) || 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, "Cannot allocate memory for file time table"); return(-1); } /* * get random name and create temporary scratch file, unlink name * so it will get removed on exit */ memcpy(tempbase, _TFILE_BASE, sizeof(_TFILE_BASE)); if ((ffd = mkstemp(tempfile)) == -1) { syswarn(1, errno, "Unable to create temporary file: %s", tempfile); return(-1); } (void)unlink(tempfile); return(0); } /* * chk_ftime() * looks up entry in file time hash table. If not found, the file is * added to the hash table and the file named stored in the scratch file. * If a file with the same name is found, the file times are compared and * the most recent file time is retained. If the new file was younger (or * was not in the database) the new file is selected for storage. * Return: * 0 if file should be added to the archive, 1 if it should be skipped, * -1 on error */ int chk_ftime(ARCHD *arcn) { FTM *pt; int namelen; u_int indx; char ckname[PAXPATHLEN+1]; /* * no info, go ahead and add to archive */ if (ftab == NULL) return(0); /* * hash the pathname and look up in table */ namelen = arcn->nlen; indx = st_hash(arcn->name, namelen, F_TAB_SZ); if ((pt = ftab[indx]) != NULL) { /* * the hash chain is not empty, walk down looking for match * only read up the path names if the lengths match, speeds * up the search a lot */ while (pt != NULL) { if (pt->namelen == namelen) { /* * potential match, have to read the name * from the scratch file. */ if (lseek(ffd,pt->seek,SEEK_SET) != pt->seek) { syswarn(1, errno, "Failed ftime table seek"); return(-1); } if (read(ffd, ckname, namelen) != namelen) { syswarn(1, errno, "Failed ftime table read"); return(-1); } /* * if the names match, we are done */ if (!strncmp(ckname, arcn->name, namelen)) break; } /* * try the next entry on the chain */ pt = pt->fow; } if (pt != NULL) { /* * found the file, compare the times, save the newer */ if (timespeccmp(&arcn->sb.st_mtim, &pt->mtim, >)) { /* * file is newer */ pt->mtim = arcn->sb.st_mtim; 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) { pt->mtim = arcn->sb.st_mtim; pt->namelen = namelen; pt->fow = ftab[indx]; ftab[indx] = pt; return(0); } syswarn(1, errno, "Failed write to file time table"); } else syswarn(1, errno, "Failed seek on file time table"); } else paxwarn(1, "File time table ran out of memory"); if (pt != NULL) free(pt); return(-1); } /* * 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; u_int indx; int fd; /* create the placeholder */ fd = open(path0, O_WRONLY | O_CREAT | O_EXCL | O_CLOEXEC, 0600); if (fd == -1) return (-1); if (fstat(fd, &sb) == -1) { unlink(path0); close(fd); return (-1); } close(fd); if (havechd && *path0 != '/') { if ((path = realpath(path0, NULL)) == NULL) { syswarn(1, errno, "Cannot canonicalize %s", path0); unlink(path0); return (-1); } } else if ((path = strdup(path0)) == NULL) { syswarn(1, errno, "defered symlink path"); unlink(path0); return (-1); } if ((value = strdup(value0)) == NULL) { syswarn(1, errno, "defered symlink value"); 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, "defered 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; u_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, "deferred symlink hardlink"); return (-1); } if (havechd && *path != '/') { if ((p->sp_path = realpath(path, NULL)) == NULL) { syswarn(1, errno, "Cannot canonicalize %s", path); free(p); return (-1); } } else if ((p->sp_path = strdup(path)) == NULL) { syswarn(1, errno, "defered symlink hardlink path"); 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, "deferred symlink removal"); return (0); } err = 0; if (first != NULL) { /* 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; } if (symlink(s->sli_value, path)) { if (!in_sig) { const char *qualifier = ""; if (err) qualifier = " hardlink"; else err = errno; syswarn(1, err, "deferred symlink%s: %s", 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)) mode &= ~(SETBITS); } if (pmode) set_pmode(path, mode); if (patime || pmtime) set_ftime(path, &sb.st_mtim, &sb.st_atim, 0); /* * 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; u_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). */ /* * name_start() * create the interactive rename table * Return: * 0 if successful, -1 otherwise */ int name_start(void) { if (ntab != NULL) return(0); if ((ntab = calloc(N_TAB_SZ, sizeof(NAMT *))) == NULL) { paxwarn(1, "Cannot allocate memory for interactive rename table"); return(-1); } return(0); } /* * add_name() * add the new name to old name mapping just created by the user. * If an old name mapping is found (there may be duplicate names on an * archive) only the most recent is kept. * Return: * 0 if added, -1 otherwise */ int add_name(char *oname, int onamelen, char *nname) { NAMT *pt; u_int indx; if (ntab == NULL) { /* * should never happen */ paxwarn(0, "No interactive rename table, links may fail"); return(0); } /* * look to see if we have already mapped this file, if so we * will update it */ indx = st_hash(oname, onamelen, N_TAB_SZ); if ((pt = ntab[indx]) != NULL) { /* * look down the has chain for the file */ while ((pt != NULL) && (strcmp(oname, pt->oname) != 0)) pt = pt->fow; if (pt != NULL) { /* * found an old mapping, replace it with the new one * the user just input (if it is different) */ if (strcmp(nname, pt->nname) == 0) return(0); free(pt->nname); if ((pt->nname = strdup(nname)) == NULL) { paxwarn(1, "Cannot update rename table"); return(-1); } return(0); } } /* * this is a new mapping, add it to the table */ if ((pt = malloc(sizeof(NAMT))) != NULL) { if ((pt->oname = strdup(oname)) != NULL) { if ((pt->nname = strdup(nname)) != NULL) { pt->fow = ntab[indx]; ntab[indx] = pt; return(0); } free(pt->oname); } free(pt); } paxwarn(1, "Interactive rename table out of memory"); return(-1); } /* * sub_name() * look up a link name to see if it points at a file that has been * remapped by the user. If found, the link is adjusted to contain the * new name (oname is the link to name) */ void sub_name(char *oname, int *onamelen, int onamesize) { NAMT *pt; u_int indx; if (ntab == NULL) return; /* * look the name up in the hash table */ indx = st_hash(oname, *onamelen, N_TAB_SZ); if ((pt = ntab[indx]) == NULL) return; while (pt != NULL) { /* * walk down the hash chain looking for a match */ if (strcmp(oname, pt->oname) == 0) { /* * found it, replace it with the new name * and return (we know that oname has enough space) */ *onamelen = strlcpy(oname, pt->nname, onamesize); if (*onamelen >= onamesize) *onamelen = onamesize - 1; /* XXX truncate? */ return; } pt = pt->fow; } /* * no match, just return */ } #ifndef NOCPIO /* * device/inode mapping table routines * (used with formats that store device and inodes fields) * * device/inode mapping tables remap the device field in a archive header. The * device/inode fields are used to determine when files are hard links to each * other. However these values have very little meaning outside of that. This * database is used to solve one of two different problems. * * 1) when files are appended to an archive, while the new files may have hard * links to each other, you cannot determine if they have hard links to any * file already stored on the archive from a prior run of pax. We must assume * that these inode/device pairs are unique only within a SINGLE run of pax * (which adds a set of files to an archive). So we have to make sure the * inode/dev pairs we add each time are always unique. We do this by observing * while the inode field is very dense, the use of the dev field is fairly * sparse. Within each run of pax, we remap any device number of a new archive * member that has a device number used in a prior run and already stored in a * file on the archive. During the read phase of the append, we store the * device numbers used and mark them to not be used by any file during the * write phase. If during write we go to use one of those old device numbers, * we remap it to a new value. * * 2) Often the fields in the archive header used to store these values are * too small to store the entire value. The result is an inode or device value * which can be truncated. This really can foul up an archive. With truncation * we end up creating links between files that are really not links (after * truncation the inodes are the same value). We address that by detecting * truncation and forcing a remap of the device field to split truncated * inodes away from each other. Each truncation creates a pattern of bits that * are removed. We use this pattern of truncated bits to partition the inodes * on a single device to many different devices (each one represented by the * truncated bit pattern). All inodes on the same device that have the same * truncation pattern are mapped to the same new device. Two inodes that * truncate to the same value clearly will always have different truncation * bit patterns, so they will be split from away each other. When we spot * device truncation we remap the device number to a non truncated value. * (for more info see table.h for the data structures involved). */ static DEVT *chk_dev(dev_t, int); /* * dev_start() * create the device mapping table * Return: * 0 if successful, -1 otherwise */ int dev_start(void) { if (dtab != NULL) return(0); if ((dtab = calloc(D_TAB_SZ, sizeof(DEVT *))) == NULL) { paxwarn(1, "Cannot allocate memory for device mapping table"); return(-1); } return(0); } /* * add_dev() * add a device number to the table. this will force the device to be * remapped to a new value if it be used during a write phase. This * function is called during the read phase of an append to prohibit the * use of any device number already in the archive. * Return: * 0 if added ok, -1 otherwise */ int add_dev(ARCHD *arcn) { if (chk_dev(arcn->sb.st_dev, 1) == NULL) return(-1); return(0); } /* * chk_dev() * check for a device value in the device table. If not found and the add * flag is set, it is added. This does NOT assign any mapping values, just * adds the device number as one that need to be remapped. If this device * is already mapped, just return with a pointer to that entry. * Return: * pointer to the entry for this device in the device map table. Null * if the add flag is not set and the device is not in the table (it is * not been seen yet). If add is set and the device cannot be added, null * is returned (indicates an error). */ static DEVT * chk_dev(dev_t dev, int add) { DEVT *pt; u_int indx; if (dtab == NULL) return(NULL); /* * look to see if this device is already in the table */ indx = ((unsigned)dev) % D_TAB_SZ; if ((pt = dtab[indx]) != NULL) { while ((pt != NULL) && (pt->dev != dev)) pt = pt->fow; /* * found it, return a pointer to it */ if (pt != NULL) return(pt); } /* * not in table, we add it only if told to as this may just be a check * to see if a device number is being used. */ if (add == 0) return(NULL); /* * allocate a node for this device and add it to the front of the hash * chain. Note we do not assign remaps values here, so the pt->list * list must be NULL. */ if ((pt = malloc(sizeof(DEVT))) == NULL) { paxwarn(1, "Device map table out of memory"); return(NULL); } pt->dev = dev; pt->list = NULL; pt->fow = dtab[indx]; dtab[indx] = pt; return(pt); } /* * map_dev() * given an inode and device storage mask (the mask has a 1 for each bit * the archive format is able to store in a header), we check for inode * and device truncation and remap the device as required. Device mapping * can also occur when during the read phase of append a device number was * seen (and was marked as do not use during the write phase). WE ASSUME * that unsigned longs are the same size or bigger than the fields used * for ino_t and dev_t. If not the types will have to be changed. * Return: * 0 if all ok, -1 otherwise. */ int map_dev(ARCHD *arcn, u_long dev_mask, u_long ino_mask) { DEVT *pt; DLIST *dpt; static dev_t lastdev = 0; /* next device number to try */ int trc_ino = 0; int trc_dev = 0; ino_t trunc_bits = 0; ino_t nino; if (dtab == NULL) return(0); /* * check for device and inode truncation, and extract the truncated * bit pattern. */ if ((arcn->sb.st_dev & (dev_t)dev_mask) != arcn->sb.st_dev) ++trc_dev; if ((nino = arcn->sb.st_ino & (ino_t)ino_mask) != arcn->sb.st_ino) { ++trc_ino; trunc_bits = arcn->sb.st_ino & (ino_t)(~ino_mask); } /* * see if this device is already being mapped, look up the device * then find the truncation bit pattern which applies */ if ((pt = chk_dev(arcn->sb.st_dev, 0)) != NULL) { /* * this device is already marked to be remapped */ for (dpt = pt->list; dpt != NULL; dpt = dpt->fow) if (dpt->trunc_bits == trunc_bits) break; if (dpt != NULL) { /* * we are being remapped for this device and pattern * change the device number to be stored and return */ arcn->sb.st_dev = dpt->dev; arcn->sb.st_ino = nino; return(0); } } else { /* * this device is not being remapped YET. if we do not have any * form of truncation, we do not need a remap */ if (!trc_ino && !trc_dev) return(0); /* * we have truncation, have to add this as a device to remap */ if ((pt = chk_dev(arcn->sb.st_dev, 1)) == NULL) goto bad; /* * if we just have a truncated inode, we have to make sure that * all future inodes that do not truncate (they have the * truncation pattern of all 0's) continue to map to the same * device number. We probably have already written inodes with * this device number to the archive with the truncation * pattern of all 0's. So we add the mapping for all 0's to the * same device number. */ if (!trc_dev && (trunc_bits != 0)) { if ((dpt = malloc(sizeof(DLIST))) == NULL) goto bad; dpt->trunc_bits = 0; dpt->dev = arcn->sb.st_dev; dpt->fow = pt->list; pt->list = dpt; } } /* * look for a device number not being used. We must watch for wrap * around on lastdev (so we do not get stuck looking forever!) */ while (++lastdev > 0) { if (chk_dev(lastdev, 0) != NULL) continue; /* * found an unused value. If we have reached truncation point * for this format we are hosed, so we give up. Otherwise we * mark it as being used. */ if (((lastdev & ((dev_t)dev_mask)) != lastdev) || (chk_dev(lastdev, 1) == NULL)) goto bad; break; } if ((lastdev <= 0) || ((dpt = malloc(sizeof(DLIST))) == NULL)) goto bad; /* * got a new device number, store it under this truncation pattern. * change the device number this file is being stored with. */ dpt->trunc_bits = trunc_bits; dpt->dev = lastdev; dpt->fow = pt->list; pt->list = dpt; arcn->sb.st_dev = lastdev; arcn->sb.st_ino = nino; return(0); bad: paxwarn(1, "Unable to fix truncated inode/device field when storing %s", arcn->name); paxwarn(0, "Archive may create improper hard links when extracted"); return(0); } #endif /* NOCPIO */ /* * directory access/mod time reset table routines (for directories READ by pax) * * The pax -t flag requires that access times of archive files be the same * before being read by pax. For regular files, access time is restored after * the file has been copied. This database provides the same functionality for * directories read during file tree traversal. Restoring directory access time * is more complex than files since directories may be read several times until * all the descendants in their subtree are visited by fts. Directory access * and modification times are stored during the fts pre-order visit (done * before any descendants in the subtree are visited) and restored after the * fts post-order visit (after all the descendants have been visited). In the * case of premature exit from a subtree (like from the effects of -n), any * directory entries left in this database are reset during final cleanup * operations of pax. Entries are hashed by inode number for fast lookup. */ /* * atdir_start() * create the directory access time database for directories READ by pax. * Return: * 0 is created ok, -1 otherwise. */ int atdir_start(void) { if (atab != NULL) return(0); if ((atab = calloc(A_TAB_SZ, sizeof(ATDIR *))) == NULL) { paxwarn(1,"Cannot allocate space for directory access time table"); return(-1); } return(0); } /* * atdir_end() * walk through the directory access time table and reset the access time * of any directory who still has an entry left in the database. These * entries are for directories READ by pax */ void atdir_end(void) { ATDIR *pt; int i; if (atab == NULL) return; /* * for each non-empty hash table entry reset all the directories * chained there. */ for (i = 0; i < A_TAB_SZ; ++i) { if ((pt = atab[i]) == NULL) continue; /* * remember to force the times, set_ftime() looks at pmtime * and patime, which only applies to things CREATED by pax, * not read by pax. Read time reset is controlled by -t. */ for (; pt != NULL; pt = pt->fow) set_attr(&pt->ft, 1, 0, 0, 0); } } /* * add_atdir() * add a directory to the directory access time table. Table is hashed * and chained by inode number. This is for directories READ by pax */ void add_atdir(char *fname, dev_t dev, ino_t ino, const struct timespec *mtimp, const struct timespec *atimp) { ATDIR *pt; sigset_t allsigs, savedsigs; u_int indx; if (atab == NULL) return; /* * make sure this directory is not already in the table, if so just * return (the older entry always has the correct time). The only * way this will happen is when the same subtree can be traversed by * different args to pax and the -n option is aborting fts out of a * subtree before all the post-order visits have been made. */ indx = ((unsigned)ino) % A_TAB_SZ; if ((pt = atab[indx]) != NULL) { while (pt != NULL) { if ((pt->ft.ft_ino == ino) && (pt->ft.ft_dev == dev)) break; pt = pt->fow; } /* * oops, already there. Leave it alone. */ if (pt != NULL) return; } /* * add it to the front of the hash chain */ sigfillset(&allsigs); sigprocmask(SIG_BLOCK, &allsigs, &savedsigs); if ((pt = malloc(sizeof *pt)) != NULL) { if ((pt->ft.ft_name = strdup(fname)) != NULL) { pt->ft.ft_dev = dev; pt->ft.ft_ino = ino; pt->ft.ft_mtim = *mtimp; pt->ft.ft_atim = *atimp; pt->fow = atab[indx]; atab[indx] = pt; sigprocmask(SIG_SETMASK, &savedsigs, NULL); return; } free(pt); } sigprocmask(SIG_SETMASK, &savedsigs, NULL); paxwarn(1, "Directory access time reset table ran out of memory"); } /* * get_atdir() * look up a directory by inode and device number to obtain the access * and modification time you want to set to. If found, the modification * and access time parameters are set and the entry is removed from the * table (as it is no longer needed). These are for directories READ by * pax * Return: * 0 if found, -1 if not found. */ int do_atdir(const char *name, dev_t dev, ino_t ino) { ATDIR *pt; ATDIR **ppt; sigset_t allsigs, savedsigs; u_int indx; if (atab == NULL) return(-1); /* * hash by inode and search the chain for an inode and device match */ indx = ((unsigned)ino) % A_TAB_SZ; if ((pt = atab[indx]) == NULL) return(-1); ppt = &(atab[indx]); while (pt != NULL) { if ((pt->ft.ft_ino == ino) && (pt->ft.ft_dev == dev)) break; /* * no match, go to next one */ ppt = &(pt->fow); pt = pt->fow; } /* * return if we did not find it. */ if (pt == NULL || pt->ft.ft_name == NULL || strcmp(name, pt->ft.ft_name) == 0) return(-1); /* * found it. set the times and remove the entry from the table. */ set_attr(&pt->ft, 1, 0, 0, 0); sigfillset(&allsigs); sigprocmask(SIG_BLOCK, &allsigs, &savedsigs); *ppt = pt->fow; sigprocmask(SIG_SETMASK, &savedsigs, NULL); free(pt->ft.ft_name); free(pt); return(0); } /* * directory access mode and time storage routines (for directories CREATED * by pax). * * Pax requires that extracted directories, by default, have their access/mod * times and permissions set to the values specified in the archive. During the * actions of extracting (and creating the destination subtree during -rw copy) * directories extracted may be modified after being created. Even worse is * that these directories may have been created with file permissions which * prohibits any descendants of these directories from being extracted. When * directories are created by pax, access rights may be added to permit the * creation of files in their subtree. Every time pax creates a directory, the * times and file permissions specified by the archive are stored. After all * files have been extracted (or copied), these directories have their times * and file modes reset to the stored values. The directory info is restored in * reverse order as entries were added from root to leaf: to restore atime * properly, we must go backwards. */ /* * dir_start() * set up the directory time and file mode storage for directories CREATED * by pax. * Return: * 0 if ok, -1 otherwise */ int dir_start(void) { if (dirp != NULL) return(0); dirsize = DIRP_SIZE; if ((dirp = reallocarray(NULL, dirsize, sizeof(DIRDATA))) == NULL) { paxwarn(1, "Unable to allocate memory for directory times"); return(-1); } return(0); } /* * add_dir() * add the mode and times for a newly CREATED directory * name is name of the directory, psb the stat buffer with the data in it, * frc_mode is a flag that says whether to force the setting of the mode * (ignoring the user set values for preserving file mode). Frc_mode is * for the case where we created a file and found that the resulting * directory was not writeable and the user asked for file modes to NOT * be preserved. (we have to preserve what was created by default, so we * have to force the setting at the end. this is stated explicitly in the * pax spec) */ void add_dir(char *name, struct stat *psb, int frc_mode) { DIRDATA *dblk; sigset_t allsigs, savedsigs; char realname[PATH_MAX], *rp; if (dirp == NULL) return; if (havechd && *name != '/') { if ((rp = realpath(name, realname)) == NULL) { paxwarn(1, "Cannot canonicalize %s", name); return; } name = rp; } if (dircnt == dirsize) { dblk = reallocarray(dirp, dirsize * 2, sizeof(DIRDATA)); if (dblk == NULL) { paxwarn(1, "Unable to store mode and times for created" " directory: %s", name); return; } sigprocmask(SIG_BLOCK, &allsigs, &savedsigs); dirp = dblk; dirsize *= 2; sigprocmask(SIG_SETMASK, &savedsigs, NULL); } dblk = &dirp[dircnt]; if ((dblk->ft.ft_name = strdup(name)) == NULL) { paxwarn(1, "Unable to store mode and times for created" " directory: %s", name); return; } dblk->ft.ft_mtim = psb->st_mtim; dblk->ft.ft_atim = psb->st_atim; dblk->ft.ft_ino = psb->st_ino; dblk->ft.ft_dev = psb->st_dev; dblk->mode = psb->st_mode & ABITS; dblk->frc_mode = frc_mode; sigprocmask(SIG_BLOCK, &allsigs, &savedsigs); ++dircnt; sigprocmask(SIG_SETMASK, &savedsigs, NULL); } /* * delete_dir() * When we rmdir a directory, we may want to make sure we don't * later warn about being unable to set its mode and times. */ void delete_dir(dev_t dev, ino_t ino) { DIRDATA *dblk; char *name; size_t i; if (dirp == NULL) return; for (i = 0; i < dircnt; i++) { dblk = &dirp[i]; if (dblk->ft.ft_name == NULL) continue; if (dblk->ft.ft_dev == dev && dblk->ft.ft_ino == ino) { name = dblk->ft.ft_name; dblk->ft.ft_name = NULL; free(name); break; } } } /* * proc_dir(int in_sig) * process all file modes and times stored for directories CREATED * by pax. If in_sig is set, we're in a signal handler and can't * free stuff. */ void proc_dir(int in_sig) { DIRDATA *dblk; size_t cnt; if (dirp == NULL) return; /* * read backwards through the file and process each directory */ cnt = dircnt; while (cnt-- > 0) { dblk = &dirp[cnt]; /* * If we remove a directory we created, we replace the * ft_name with NULL. Ignore those. */ if (dblk->ft.ft_name == NULL) continue; /* * frc_mode set, make sure we set the file modes even if * the user didn't ask for it (see file_subs.c for more info) */ set_attr(&dblk->ft, 0, dblk->mode, pmode || dblk->frc_mode, in_sig); if (!in_sig) free(dblk->ft.ft_name); } if (!in_sig) free(dirp); dirp = NULL; dircnt = 0; } /* * database independent routines */ /* * st_hash() * hashes filenames to a u_int for hashing into a table. Looks at the tail * end of file, as this provides far better distribution than any other * part of the name. For performance reasons we only care about the last * MAXKEYLEN chars (should be at LEAST large enough to pick off the file * name). Was tested on 500,000 name file tree traversal from the root * and gave almost a perfectly uniform distribution of keys when used with * prime sized tables (MAXKEYLEN was 128 in test). Hashes (sizeof int) * chars at a time and pads with 0 for last addition. * Return: * the hash value of the string MOD (%) the table size. */ static u_int st_hash(const char *name, int len, int tabsz) { const char *pt; char *dest; const char *end; int i; u_int key = 0; int steps; int res; u_int val; /* * only look at the tail up to MAXKEYLEN, we do not need to waste * time here (remember these are pathnames, the tail is what will * spread out the keys) */ if (len > MAXKEYLEN) { pt = &(name[len - MAXKEYLEN]); len = MAXKEYLEN; } else pt = name; /* * calculate the number of u_int size steps in the string and if * there is a runt to deal with */ steps = len/sizeof(u_int); res = len % sizeof(u_int); /* * add up the value of the string in unsigned integer sized pieces * too bad we cannot have unsigned int aligned strings, then we * could avoid the expensive copy. */ for (i = 0; i < steps; ++i) { end = pt + sizeof(u_int); dest = (char *)&val; while (pt < end) *dest++ = *pt++; key += val; } /* * add in the runt padded with zero to the right */ if (res) { val = 0; end = pt + res; dest = (char *)&val; while (pt < end) *dest++ = *pt++; key += val; } /* * return the result mod the table size */ return(key % tabsz); }
