/* $NetBSD: file_subs.c,v 1.64.10.1 2024/08/07 10:52:49 martin 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. */ #if HAVE_NBTOOL_CONFIG_H #include "nbtool_config.h" #endif #include #if !defined(lint) #if 0 static char sccsid[] = "@(#)file_subs.c 8.1 (Berkeley) 5/31/93"; #else __RCSID("$NetBSD: file_subs.c,v 1.64.10.1 2024/08/07 10:52:49 martin Exp $"); #endif #endif /* not lint */ #include #include #include #include #include #include #include #include #include #include #include #include #include "pax.h" #include "extern.h" #include "options.h" char *xtmp_name; static int mk_link(char *,struct stat *,char *, int); static int warn_broken; /* * routines that deal with file operations such as: creating, removing; * and setting access modes, uid/gid and times of files */ #define SET_BITS (S_ISUID | S_ISGID) #define FILE_BITS (S_IRWXU | S_IRWXG | S_IRWXO) #define A_BITS (FILE_BITS | SET_BITS | S_ISVTX) /* * The S_ISVTX (sticky bit) can be set by non-superuser on directories * but not other kinds of files. */ #define FILEBITS(dir) ((dir) ? (FILE_BITS | S_ISVTX) : FILE_BITS) #define SETBITS(dir) ((dir) ? SET_BITS : (SET_BITS | S_ISVTX)) static mode_t apply_umask(mode_t mode) { static mode_t cached_umask; static int cached_umask_valid; if (!cached_umask_valid) { cached_umask = umask(0); umask(cached_umask); cached_umask_valid = 1; } return mode & ~cached_umask; } /* * file_creat() * Create and open a file. * Return: * file descriptor or -1 for failure */ int file_creat(ARCHD *arcn, int write_to_hardlink) { int fd = -1; int oerrno; /* * Some horribly busted tar implementations, have directory nodes * that end in a /, but they mark as files. Compensate for that * by not creating a directory node at this point, but a file node, * and not creating the temp file. */ if (arcn->nlen != 0 && arcn->name[arcn->nlen - 1] == '/') { if (!warn_broken) { tty_warn(0, "Archive was created with a broken tar;" " file `%s' is a directory, but marked as plain.", arcn->name); warn_broken = 1; } return -1; } /* * In "cpio" archives it's usually the last record of a set of * hardlinks which includes the contents of the file. We cannot * use a tempory file in that case because we couldn't link it * with the existing other hardlinks after restoring the contents * to it. And it's also useless to create the hardlink under a * temporary name because the other hardlinks would have partial * contents while restoring. */ if (write_to_hardlink) return (open(arcn->name, O_TRUNC | O_EXCL | O_RDWR, 0)); /* * Create a temporary file name so that the file doesn't have partial * contents while restoring. */ arcn->tmp_name = malloc(arcn->nlen + 8); if (arcn->tmp_name == NULL) { syswarn(1, errno, "Cannot malloc %d bytes", arcn->nlen + 8); return -1; } if (xtmp_name != NULL) abort(); xtmp_name = arcn->tmp_name; for (;;) { /* * try to create the temporary file we use to restore the * contents info. if this fails, keep checking all the nodes * in the path until chk_path() finds that it cannot fix * anything further. if that happens we just give up. */ (void)snprintf(arcn->tmp_name, arcn->nlen + 8, "%s.XXXXXX", arcn->name); fd = mkstemp(arcn->tmp_name); if (fd >= 0) break; oerrno = errno; if (nodirs || chk_path(arcn->name,arcn->sb.st_uid,arcn->sb.st_gid) < 0) { (void)fflush(listf); syswarn(1, oerrno, "Cannot create %s", arcn->tmp_name); xtmp_name = NULL; free(arcn->tmp_name); arcn->tmp_name = NULL; return -1; } } return fd; } /* * file_cleanup() * Close file descriptor to a file just created by pax. * Unlinks any temporary file. */ void file_cleanup(ARCHD *arcn, int fd) { char *tmp_name; if (fd < 0) return; tmp_name = (arcn->tmp_name != NULL) ? arcn->tmp_name : arcn->name; if (close(fd) < 0) syswarn(0, errno, "Cannot close file descriptor on %s", tmp_name); /* No temporary file to cleanup? */ if (arcn->tmp_name == NULL) return; /* Cleanup the temporary file. */ if (unlink(arcn->tmp_name) < 0) { syswarn(0, errno, "Cannot unlink %s", arcn->tmp_name); } free(arcn->tmp_name); arcn->tmp_name = NULL; xtmp_name = NULL; } /* * file_close() * Close file descriptor to a file just created by pax. Sets modes, * ownership and times as required. */ void file_close(ARCHD *arcn, int fd) { char *tmp_name; int res; if (fd < 0) return; tmp_name = (arcn->tmp_name != NULL) ? arcn->tmp_name : arcn->name; if (close(fd) < 0) syswarn(0, errno, "Cannot close file descriptor on %s", tmp_name); /* * set owner/groups first as this may strip off mode bits we want * then set file permission modes. Then set file access and * modification times. */ if (pids) res = set_ids(tmp_name, arcn->sb.st_uid, arcn->sb.st_gid); else res = 0; /* * IMPORTANT SECURITY NOTE: * if not preserving mode or we cannot set uid/gid, then PROHIBIT * set uid/gid bits but restore the file modes (since mkstemp doesn't). */ if (!pmode || res) arcn->sb.st_mode &= ~SETBITS(0); if (pmode) set_pmode(tmp_name, arcn->sb.st_mode); else set_pmode(tmp_name, apply_umask((arcn->sb.st_mode & FILEBITS(0)))); if (patime || pmtime) set_ftime(tmp_name, arcn->sb.st_mtime, arcn->sb.st_atime, 0, 0); /* Did we write directly to the target file? */ if (arcn->tmp_name == NULL) return; /* * Finally, now the temp file is fully instantiated rename it to * the desired file name. */ if (rename(tmp_name, arcn->name) < 0) { syswarn(0, errno, "Cannot rename %s to %s", tmp_name, arcn->name); (void)unlink(tmp_name); } #if HAVE_STRUCT_STAT_ST_FLAGS if (pfflags && arcn->type != PAX_SLK) set_chflags(arcn->name, arcn->sb.st_flags); #endif free(arcn->tmp_name); arcn->tmp_name = NULL; xtmp_name = NULL; } /* * lnk_creat() * Create a hard link to arcn->ln_name from arcn->name. arcn->ln_name * must exist; * Return: * 0 if ok, -1 otherwise */ int lnk_creat(ARCHD *arcn, int *payload) { struct stat sb; /* * Check if this hardlink carries the "payload". In "cpio" archives * it's usually the last record of a set of hardlinks which includes * the contents of the file. * */ *payload = S_ISREG(arcn->sb.st_mode) && (arcn->sb.st_size > 0) && (arcn->sb.st_size <= arcn->skip); /* * We may be running as root, so we have to be sure that link target * is not a directory, so we lstat and check. XXX: This is still racy. */ if (lstat(arcn->ln_name, &sb) != -1 && S_ISDIR(sb.st_mode)) { tty_warn(1, "A hard link to the directory %s is not allowed", arcn->ln_name); return -1; } return mk_link(arcn->ln_name, &sb, arcn->name, 0); } /* * cross_lnk() * Create a hard link to arcn->org_name from arcn->name. Only used in copy * with the -l flag. No warning or error if this does not succeed (we will * then just create the file) * Return: * 1 if copy() should try to create this file node * 0 if cross_lnk() ok, -1 for fatal flaw (like linking to self). */ int cross_lnk(ARCHD *arcn) { /* * try to make a link to original file (-l flag in copy mode). make * sure we do not try to link to directories in case we are running as * root (and it might succeed). */ if (arcn->type == PAX_DIR) return 1; return mk_link(arcn->org_name, &(arcn->sb), arcn->name, 1); } /* * chk_same() * In copy mode if we are not trying to make hard links between the src * and destinations, make sure we are not going to overwrite ourselves by * accident. This slows things down a little, but we have to protect all * those people who make typing errors. * Return: * 1 the target does not exist, go ahead and copy * 0 skip it file exists (-k) or may be the same as source file */ int chk_same(ARCHD *arcn) { struct stat sb; /* * if file does not exist, return. if file exists and -k, skip it * quietly */ if (lstat(arcn->name, &sb) < 0) return 1; if (kflag) return 0; /* * better make sure the user does not have src == dest by mistake */ if ((arcn->sb.st_dev == sb.st_dev) && (arcn->sb.st_ino == sb.st_ino)) { tty_warn(1, "Unable to copy %s, file would overwrite itself", arcn->name); return 0; } return 1; } /* * mk_link() * try to make a hard link between two files. if ign set, we do not * complain. * Return: * 0 if successful (or we are done with this file but no error, such as * finding the from file exists and the user has set -k). * 1 when ign was set to indicates we could not make the link but we * should try to copy/extract the file as that might work (and is an * allowed option). -1 an error occurred. */ static int mk_link(char *to, struct stat *to_sb, char *from, int ign) { struct stat sb; int oerrno; /* * if from file exists, it has to be unlinked to make the link. If the * file exists and -k is set, skip it quietly */ if (lstat(from, &sb) == 0) { if (kflag) return 0; /* * make sure it is not the same file, protect the user */ if ((to_sb->st_dev==sb.st_dev)&&(to_sb->st_ino == sb.st_ino)) { tty_warn(1, "Cannot link file %s to itself", to); return -1; } /* * try to get rid of the file, based on the type */ if (S_ISDIR(sb.st_mode) && strcmp(from, ".") != 0) { if (rmdir(from) < 0) { syswarn(1, errno, "Cannot remove %s", from); return -1; } } else if (unlink(from) < 0) { if (!ign) { syswarn(1, errno, "Cannot remove %s", from); return -1; } return 1; } } /* * from file is gone (or did not exist), try to make the hard link. * if it fails, check the path and try it again (if chk_path() says to * try again) */ for (;;) { if (link(to, from) == 0) break; oerrno = errno; if (chk_path(from, to_sb->st_uid, to_sb->st_gid) == 0) continue; if (!ign) { syswarn(1, oerrno, "Cannot link to %s from %s", to, from); return -1; } return 1; } /* * all right the link was made */ return 0; } /* * node_creat() * create an entry in the file system (other than a file or hard link). * If successful, sets uid/gid modes and times as required. * Return: * 0 if ok, -1 otherwise */ int node_creat(ARCHD *arcn) { int res; int ign = 0; int oerrno; int pass = 0; mode_t file_mode; struct stat sb; char target[MAXPATHLEN]; char *nm = arcn->name; int len; /* * create node based on type, if that fails try to unlink the node and * try again. finally check the path and try again. As noted in the * file and link creation routines, this method seems to exhibit the * best performance in general use workloads. */ file_mode = arcn->sb.st_mode & FILEBITS(arcn->type == PAX_DIR); for (;;) { switch (arcn->type) { case PAX_DIR: /* * If -h (or -L) was given in tar-mode, follow the * potential symlink chain before trying to create the * directory. */ if (strcmp(NM_TAR, argv0) == 0 && Lflag) { while (lstat(nm, &sb) == 0 && S_ISLNK(sb.st_mode)) { len = readlink(nm, target, sizeof target - 1); if (len == -1) { syswarn(0, errno, "cannot follow symlink %s " "in chain for %s", nm, arcn->name); res = -1; goto badlink; } target[len] = '\0'; nm = target; } } res = domkdir(nm, file_mode); badlink: if (ign) res = 0; break; case PAX_CHR: file_mode |= S_IFCHR; res = mknod(nm, file_mode, arcn->sb.st_rdev); break; case PAX_BLK: file_mode |= S_IFBLK; res = mknod(nm, file_mode, arcn->sb.st_rdev); break; case PAX_FIF: res = mkfifo(nm, file_mode); break; case PAX_SCK: /* * Skip sockets, operation has no meaning under BSD */ tty_warn(0, "%s skipped. Sockets cannot be copied or extracted", nm); return (-1); case PAX_SLK: res = symlink(arcn->ln_name, nm); break; case PAX_CTG: case PAX_HLK: case PAX_HRG: case PAX_REG: default: /* * we should never get here */ tty_warn(0, "%s has an unknown file type, skipping", nm); return (-1); } /* * if we were able to create the node break out of the loop, * otherwise try to unlink the node and try again. if that * fails check the full path and try a final time. */ if (res == 0) break; /* * we failed to make the node */ oerrno = errno; switch (pass++) { case 0: if ((ign = unlnk_exist(nm, arcn->type)) < 0) return (-1); continue; case 1: if (nodirs || chk_path(nm, arcn->sb.st_uid, arcn->sb.st_gid) < 0) { syswarn(1, oerrno, "Cannot create %s", nm); return (-1); } continue; } /* * it must be a file that exists but we can't create or * remove, but we must avoid the infinite loop. */ break; } /* * we were able to create the node. set uid/gid, modes and times */ if (pids) res = set_ids(nm, arcn->sb.st_uid, arcn->sb.st_gid); else res = 0; /* * IMPORTANT SECURITY NOTE: * if not preserving mode or we cannot set uid/gid, then PROHIBIT any * set uid/gid bits */ if (!pmode || res) arcn->sb.st_mode &= ~SETBITS(arcn->type == PAX_DIR); if (pmode) set_pmode(arcn->name, arcn->sb.st_mode); if (arcn->type == PAX_DIR && strcmp(NM_CPIO, argv0) != 0) { /* * Dirs must be processed again at end of extract to set times * and modes to agree with those stored in the archive. However * to allow extract to continue, we may have to also set owner * rights. This allows nodes in the archive that are children * of this directory to be extracted without failure. Both time * and modes will be fixed after the entire archive is read and * before pax exits. */ if (access(nm, R_OK | W_OK | X_OK) < 0) { if (lstat(nm, &sb) < 0) { syswarn(0, errno,"Cannot access %s (stat)", arcn->name); set_pmode(nm,file_mode | S_IRWXU); } else { /* * We have to add rights to the dir, so we make * sure to restore the mode. The mode must be * restored AS CREATED and not as stored if * pmode is not set. */ set_pmode(nm, ((sb.st_mode & FILEBITS(arcn->type == PAX_DIR)) | S_IRWXU)); if (!pmode) arcn->sb.st_mode = sb.st_mode; } /* * we have to force the mode to what was set here, * since we changed it from the default as created. */ add_dir(nm, arcn->nlen, &(arcn->sb), 1); } else if (pmode || patime || pmtime) add_dir(nm, arcn->nlen, &(arcn->sb), 0); } if (patime || pmtime) set_ftime(arcn->name, arcn->sb.st_mtime, arcn->sb.st_atime, 0, (arcn->type == PAX_SLK) ? 1 : 0); #if HAVE_STRUCT_STAT_ST_FLAGS if (pfflags && arcn->type != PAX_SLK) set_chflags(arcn->name, arcn->sb.st_flags); #endif return 0; } /* * unlnk_exist() * Remove node from file system with the specified name. We pass the type * of the node that is going to replace it. When we try to create a * directory and find that it already exists, we allow processing to * continue as proper modes etc will always be set for it later on. * Return: * 0 is ok to proceed, no file with the specified name exists * -1 we were unable to remove the node, or we should not remove it (-k) * 1 we found a directory and we were going to create a directory. */ int unlnk_exist(char *name, int type) { struct stat sb; /* * the file does not exist, or -k we are done */ if (lstat(name, &sb) < 0) return 0; if (kflag) return -1; if (S_ISDIR(sb.st_mode)) { /* * try to remove a directory, if it fails and we were going to * create a directory anyway, tell the caller (return a 1). * * don't try to remove the directory if the name is "." * otherwise later file/directory creation fails. */ if (strcmp(name, ".") == 0) return 1; if (rmdir(name) < 0) { if (type == PAX_DIR) return 1; syswarn(1, errno, "Cannot remove directory %s", name); return -1; } return 0; } /* * try to get rid of all non-directory type nodes */ if (unlink(name) < 0) { (void)fflush(listf); syswarn(1, errno, "Cannot unlink %s", name); return -1; } return 0; } /* * chk_path() * We were trying to create some kind of node in the file system and it * failed. chk_path() makes sure the path up to the node exists and is * writable. When we have to create a directory that is missing along the * path somewhere, the directory we create will be set to the same * uid/gid as the file has (when uid and gid are being preserved). * NOTE: this routine is a real performance loss. It is only used as a * last resort when trying to create entries in the file system. * Return: * -1 when it could find nothing it is allowed to fix. * 0 otherwise */ int chk_path(char *name, uid_t st_uid, gid_t st_gid) { char *spt = name; struct stat sb; int retval = -1; /* * watch out for paths with nodes stored directly in / (e.g. /bozo) */ if (*spt == '/') ++spt; for(;;) { /* * work forward from the first / and check each part of * the path */ spt = strchr(spt, '/'); if (spt == NULL) break; *spt = '\0'; /* * if it exists we assume it is a directory, it is not within * the spec (at least it seems to read that way) to alter the * file system for nodes NOT EXPLICITLY stored on the archive. * If that assumption is changed, you would test the node here * and figure out how to get rid of it (probably like some * recursive unlink()) or fix up the directory permissions if * required (do an access()). */ if (lstat(name, &sb) == 0) { *(spt++) = '/'; continue; } /* * the path fails at this point, see if we can create the * needed directory and continue on */ if (domkdir(name, S_IRWXU | S_IRWXG | S_IRWXO) == -1) { *spt = '/'; retval = -1; break; } /* * we were able to create the directory. We will tell the * caller that we found something to fix, and it is ok to try * and create the node again. */ retval = 0; if (pids) (void)set_ids(name, st_uid, st_gid); /* * make sure the user doesn't have some strange umask that * causes this newly created directory to be unusable. We fix * the modes and restore them back to the creation default at * the end of pax */ if ((access(name, R_OK | W_OK | X_OK) < 0) && (lstat(name, &sb) == 0)) { set_pmode(name, ((sb.st_mode & FILEBITS(0)) | S_IRWXU)); add_dir(name, spt - name, &sb, 1); } *(spt++) = '/'; continue; } /* * We perform one final check here, because if someone else * created the directory in parallel with us, we might return * the wrong error code, even if the directory exists now. */ if (retval == -1 && stat(name, &sb) == 0 && S_ISDIR(sb.st_mode)) retval = 0; return retval; } /* * set_ftime() * Set the access time and modification time for a named file. If frc * is non-zero we force these times to be set even if the user did not * request access and/or modification time preservation (this is also * used by -t to reset access times). * When ign is zero, only those times the user has asked for are set, the * other ones are left alone. We do not assume the un-documented feature * of many utimes() implementations that consider a 0 time value as a do * not set request. * * Unfortunately, there are systems where lutimes() is present but does * not work on some filesystem types, which cannot be detected at * compile time. This requires passing down symlink knowledge into * this function to obtain correct operation. Linux with XFS is one * example of such a system. */ void set_ftime(char *fnm, time_t mtime, time_t atime, int frc, int slk) { struct timeval tv[2]; struct stat sb; tv[0].tv_sec = atime; tv[0].tv_usec = 0; tv[1].tv_sec = mtime; tv[1].tv_usec = 0; if (!frc && (!patime || !pmtime)) { /* * if we are not forcing, only set those times the user wants * set. We get the current values of the times if we need them. */ if (lstat(fnm, &sb) == 0) { #if BSD4_4 && !HAVE_NBTOOL_CONFIG_H if (!patime) TIMESPEC_TO_TIMEVAL(&tv[0], &sb.st_atimespec); if (!pmtime) TIMESPEC_TO_TIMEVAL(&tv[1], &sb.st_mtimespec); #else if (!patime) tv[0].tv_sec = sb.st_atime; if (!pmtime) tv[1].tv_sec = sb.st_mtime; #endif } else syswarn(0, errno, "Cannot obtain file stats %s", fnm); } /* * set the times */ #if HAVE_LUTIMES if (lutimes(fnm, tv) == 0) return; if (errno != ENOSYS) /* XXX linux: lutimes is per-FS */ goto bad; #endif if (slk) return; if (utimes(fnm, tv) == -1) goto bad; return; bad: syswarn(1, errno, "Access/modification time set failed on: %s", fnm); } /* * set_ids() * set the uid and gid of a file system node * Return: * 0 when set, -1 on failure */ int set_ids(char *fnm, uid_t uid, gid_t gid) { if (geteuid() == 0) if (lchown(fnm, uid, gid)) { (void)fflush(listf); syswarn(1, errno, "Cannot set file uid/gid of %s", fnm); return -1; } return 0; } /* * set_pmode() * Set file access mode */ void set_pmode(char *fnm, mode_t mode) { mode &= A_BITS; if (lchmod(fnm, mode)) { (void)fflush(listf); syswarn(1, errno, "Cannot set permissions on %s", fnm); } return; } /* * set_chflags() * Set 4.4BSD file flags */ void set_chflags(char *fnm, u_int32_t flags) { #if 0 if (chflags(fnm, flags) < 0 && errno != EOPNOTSUPP) syswarn(1, errno, "Cannot set file flags on %s", fnm); #endif return; } /* * file_write() * Write/copy a file (during copy or archive extract). This routine knows * how to copy files with lseek holes in it. (Which are read as file * blocks containing all 0's but do not have any file blocks associated * with the data). Typical examples of these are files created by dbm * variants (.pag files). While the file size of these files are huge, the * actual storage is quite small (the files are sparse). The problem is * the holes read as all zeros so are probably stored on the archive that * way (there is no way to determine if the file block is really a hole, * we only know that a file block of all zeros can be a hole). * At this writing, no major archive format knows how to archive files * with holes. However, on extraction (or during copy, -rw) we have to * deal with these files. Without detecting the holes, the files can * consume a lot of file space if just written to disk. This replacement * for write when passed the basic allocation size of a file system block, * uses lseek whenever it detects the input data is all 0 within that * file block. In more detail, the strategy is as follows: * While the input is all zero keep doing an lseek. Keep track of when we * pass over file block boundaries. Only write when we hit a non zero * input. once we have written a file block, we continue to write it to * the end (we stop looking at the input). When we reach the start of the * next file block, start checking for zero blocks again. Working on file * block boundaries significantly reduces the overhead when copying files * that are NOT very sparse. This overhead (when compared to a write) is * almost below the measurement resolution on many systems. Without it, * files with holes cannot be safely copied. It does has a side effect as * it can put holes into files that did not have them before, but that is * not a problem since the file contents are unchanged (in fact it saves * file space). (Except on paging files for diskless clients. But since we * cannot determine one of those file from here, we ignore them). If this * ever ends up on a system where CTG files are supported and the holes * are not desired, just do a conditional test in those routines that * call file_write() and have it call write() instead. BEFORE CLOSING THE * FILE, make sure to call file_flush() when the last write finishes with * an empty block. A lot of file systems will not create an lseek hole at * the end. In this case we drop a single 0 at the end to force the * trailing 0's in the file. * ---Parameters--- * rem: how many bytes left in this file system block * isempt: have we written to the file block yet (is it empty) * sz: basic file block allocation size * cnt: number of bytes on this write * str: buffer to write * Return: * number of bytes written, -1 on write (or lseek) error. */ int file_write(int fd, char *str, int cnt, int *rem, int *isempt, int sz, char *name) { char *pt; char *end; int wcnt; char *st = str; char **strp; size_t *lenp; /* * while we have data to process */ while (cnt) { if (!*rem) { /* * We are now at the start of file system block again * (or what we think one is...). start looking for * empty blocks again */ *isempt = 1; *rem = sz; } /* * only examine up to the end of the current file block or * remaining characters to write, whatever is smaller */ wcnt = MIN(cnt, *rem); cnt -= wcnt; *rem -= wcnt; if (*isempt) { /* * have not written to this block yet, so we keep * looking for zeros */ pt = st; end = st + wcnt; /* * look for a zero filled buffer */ while ((pt < end) && (*pt == '\0')) ++pt; if (pt == end) { /* * skip, buf is empty so far */ if (fd > -1 && lseek(fd, (off_t)wcnt, SEEK_CUR) < 0) { syswarn(1, errno, "File seek on %s", name); return -1; } st = pt; continue; } /* * drat, the buf is not zero filled */ *isempt = 0; } /* * have non-zero data in this file system block, have to write */ switch (fd) { case -PAX_GLF: strp = &gnu_name_string; lenp = &gnu_name_length; break; case -PAX_GLL: strp = &gnu_link_string; lenp = &gnu_link_length; break; default: strp = NULL; lenp = NULL; break; } if (strp) { char *nstr = *strp ? realloc(*strp, *lenp + wcnt + 1) : malloc(wcnt + 1); if (nstr == NULL) { tty_warn(1, "Out of memory"); return -1; } (void)strlcpy(&nstr[*lenp], st, wcnt + 1); *strp = nstr; *lenp += wcnt; } else if (xwrite(fd, st, wcnt) != wcnt) { syswarn(1, errno, "Failed write to file %s", name); return -1; } st += wcnt; } return st - str; } /* * file_flush() * when the last file block in a file is zero, many file systems will not * let us create a hole at the end. To get the last block with zeros, we * write the last BYTE with a zero (back up one byte and write a zero). * Return: * 0 if was able to flush the file, -1 otherwise */ int file_flush(int fd, char *fname, int isempt) { static char blnk[] = "\0"; /* * silly test, but make sure we are only called when the last block is * filled with all zeros. */ if (!isempt) return 0; /* * move back one byte and write a zero */ if (lseek(fd, (off_t)-1, SEEK_CUR) < 0) { syswarn(1, errno, "Failed seek on file %s", fname); return -1; } if (write_with_restart(fd, blnk, 1) < 0) { syswarn(1, errno, "Failed write to file %s", fname); return -1; } return 0; } /* * rdfile_close() * close a file we have been reading (to copy or archive). If we have to * reset access time (tflag) do so (the times are stored in arcn). */ void rdfile_close(ARCHD *arcn, int *fd) { /* * make sure the file is open */ if (*fd < 0) return; (void)close(*fd); *fd = -1; if (!tflag) return; /* * user wants last access time reset */ set_ftime(arcn->org_name, arcn->sb.st_mtime, arcn->sb.st_atime, 1, 0); return; } /* * set_crc() * read a file to calculate its crc. This is a real drag. Archive formats * that have this, end up reading the file twice (we have to write the * header WITH the crc before writing the file contents. Oh well... * Return: * 0 if was able to calculate the crc, -1 otherwise */ int set_crc(ARCHD *arcn, int fd) { int i; int res; off_t cpcnt = 0L; u_long size; unsigned long crc = 0L; char tbuf[FILEBLK]; struct stat sb; if (fd < 0) { /* * hmm, no fd, should never happen. well no crc then. */ arcn->crc = 0L; return 0; } if ((size = (u_long)arcn->sb.st_blksize) > (u_long)sizeof(tbuf)) size = (u_long)sizeof(tbuf); /* * read all the bytes we think that there are in the file. If the user * is trying to archive an active file, forget this file. */ for(;;) { if ((res = read(fd, tbuf, size)) <= 0) break; cpcnt += res; for (i = 0; i < res; ++i) crc += (tbuf[i] & 0xff); } /* * safety check. we want to avoid archiving files that are active as * they can create inconsistent archive copies. */ if (cpcnt != arcn->sb.st_size) tty_warn(1, "File changed size %s", arcn->org_name); else if (fstat(fd, &sb) < 0) syswarn(1, errno, "Failed stat on %s", arcn->org_name); else if (arcn->sb.st_mtime != sb.st_mtime) tty_warn(1, "File %s was modified during read", arcn->org_name); else if (lseek(fd, (off_t)0L, SEEK_SET) < 0) syswarn(1, errno, "File rewind failed on: %s", arcn->org_name); else { arcn->crc = crc; return 0; } return -1; }