/* $OpenBSD: file_subs.c,v 1.57 2024/07/14 14:32:02 jca Exp $ */ /* $NetBSD: file_subs.c,v 1.4 1995/03/21 09:07:18 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/stat.h> #include <err.h> #include <errno.h> #include <fcntl.h> #include <limits.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include "pax.h" #include "extern.h" static int fset_ids(char *, int, uid_t, gid_t); static int unlnk_exist(char *, int); static int chk_path(char *, uid_t, gid_t, int); static int mk_link(char *, struct stat *, char *, int); static void fset_ftime(const char *, int, const struct timespec *, const struct timespec *, int); static void fset_pmode(char *, int, mode_t); /* * routines that deal with file operations such as: creating, removing; * and setting access modes, uid/gid and times of files */ /* * file_creat() * Create and open a file. * Return: * file descriptor or -1 for failure */ int file_creat(ARCHD *arcn) { int fd = -1; mode_t file_mode; int oerrno; /* * Assume file doesn't exist, so just try to create it, most times this * works. We have to take special handling when the file does exist. To * detect this, we use O_EXCL. For example when trying to create a * file and a character device or fifo exists with the same name, we * can accidently open the device by mistake (or block waiting to open). * If we find that the open has failed, then spend the effort to * figure out why. This strategy was found to have better average * performance in common use than checking the file (and the path) * first with lstat. */ file_mode = arcn->sb.st_mode & FILEBITS; if ((fd = open(arcn->name, O_WRONLY | O_CREAT | O_EXCL, file_mode)) >= 0) return(fd); /* * the file seems to exist. First we try to get rid of it (found to be * the second most common failure when traced). If this fails, only * then we go to the expense to check and create the path to the file */ if (unlnk_exist(arcn->name, arcn->type) != 0) return(-1); for (;;) { /* * try to open it again, if this fails, check all the nodes in * the path and give it a final try. if chk_path() finds that * it cannot fix anything, we will skip the last attempt */ if ((fd = open(arcn->name, O_WRONLY | O_CREAT | O_TRUNC, file_mode)) >= 0) break; oerrno = errno; if (nodirs || chk_path(arcn->name,arcn->sb.st_uid,arcn->sb.st_gid, 0) < 0) { syswarn(1, oerrno, "Unable to create %s", arcn->name); return(-1); } } return(fd); } /* * file_close() * Close file descriptor to a file just created by pax. Sets modes, * ownership and times as required. * Return: * 0 for success, -1 for failure */ void file_close(ARCHD *arcn, int fd) { int res = 0; if (fd < 0) return; /* * 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 = fset_ids(arcn->name, fd, arcn->sb.st_uid, arcn->sb.st_gid); /* * IMPORTANT SECURITY NOTE: * if not preserving mode or we cannot set uid/gid, then PROHIBIT * set uid/gid bits */ if (!pmode || res) arcn->sb.st_mode &= ~(SETBITS); if (pmode) fset_pmode(arcn->name, fd, arcn->sb.st_mode); if (patime || pmtime) fset_ftime(arcn->name, fd, &arcn->sb.st_mtim, &arcn->sb.st_atim, 0); if (close(fd) == -1) syswarn(0, errno, "Unable to close file descriptor on %s", arcn->name); } /* * 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) { struct stat sb; int res; /* * we may be running as root, so we have to be sure that link target * is not a directory, so we lstat and check */ if (lstat(arcn->ln_name, &sb) == -1) { syswarn(1,errno,"Unable to link to %s from %s", arcn->ln_name, arcn->name); return(-1); } if (S_ISDIR(sb.st_mode)) { paxwarn(1, "A hard link to the directory %s is not allowed", arcn->ln_name); return(-1); } res = mk_link(arcn->ln_name, &sb, arcn->name, 0); if (res == 0) { /* check for a hardlink to a placeholder symlink */ res = sltab_add_link(arcn->name, &sb); if (res < 0) { /* arrgh, it failed, clean up */ unlink(arcn->name); } } return (res); } /* * 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) == -1) 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)) { paxwarn(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)) { paxwarn(1, "Unable to 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)) { if (rmdir(from) == -1) { syswarn(1, errno, "Unable to remove %s", from); return(-1); } delete_dir(sb.st_dev, sb.st_ino); } else if (unlink(from) == -1) { if (!ign) { syswarn(1, errno, "Unable to 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 (linkat(AT_FDCWD, to, AT_FDCWD, from, 0) == 0) break; oerrno = errno; if (!nodirs && chk_path(from, to_sb->st_uid, to_sb->st_gid, ign) == 0) continue; if (!ign) { syswarn(1, oerrno, "Could not 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[PATH_MAX]; char *nm = arcn->name; int len, defer_pmode = 0; /* * 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; 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 (op_mode == OP_TAR && 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 = mkdir(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 */ paxwarn(0, "%s skipped. Sockets cannot be copied or extracted", nm); return(-1); case PAX_SLK: if (arcn->ln_name[0] != '/' && !has_dotdot(arcn->ln_name)) res = symlink(arcn->ln_name, nm); else { /* * absolute symlinks and symlinks with ".." * have to be deferred to prevent the archive * from bootstrapping itself to outside the * working directory. */ res = sltab_add_sym(nm, arcn->ln_name, arcn->sb.st_mode); if (res == 0) defer_pmode = 1; } break; case PAX_CTG: case PAX_HLK: case PAX_HRG: case PAX_REG: default: /* * we should never get here */ paxwarn(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; if ((ign = unlnk_exist(nm, arcn->type)) < 0) return(-1); if (++pass <= 1) continue; if (nodirs || chk_path(nm,arcn->sb.st_uid,arcn->sb.st_gid, 0) < 0) { syswarn(1, oerrno, "Could not create: %s", nm); return(-1); } } /* * 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); if (pmode && !defer_pmode) set_pmode(nm, arcn->sb.st_mode); if (arcn->type == PAX_DIR && op_mode != OP_CPIO) { /* * 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. To do that safely, we want the dev+ino * of the directory we created. */ if (lstat(nm, &sb) == -1) { syswarn(0, errno,"Could not access %s (stat)", nm); } else if (access(nm, R_OK | W_OK | X_OK) == -1) { /* * 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) | 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. */ arcn->sb.st_dev = sb.st_dev; arcn->sb.st_ino = sb.st_ino; add_dir(nm, &(arcn->sb), 1); } else if (pmode || patime || pmtime) { arcn->sb.st_dev = sb.st_dev; arcn->sb.st_ino = sb.st_ino; add_dir(nm, &(arcn->sb), 0); } } else if (patime || pmtime) set_ftime(nm, &arcn->sb.st_mtim, &arcn->sb.st_atim, 0); 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. */ static int unlnk_exist(char *name, int type) { struct stat sb; /* * the file does not exist, or -k we are done */ if (lstat(name, &sb) == -1) 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) */ if (rmdir(name) == -1) { if (type == PAX_DIR) return(1); syswarn(1,errno,"Unable to remove directory %s", name); return(-1); } delete_dir(sb.st_dev, sb.st_ino); return(0); } /* * try to get rid of all non-directory type nodes */ if (unlink(name) == -1) { syswarn(1, errno, "Could not 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 * writeable. 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, int ign) { char *spt = name; char *next; struct stat sb; int retval = -1; /* * watch out for paths with nodes stored directly in / (e.g. /bozo) */ while (*spt == '/') ++spt; for (;;) { /* * work forward from the first / and check each part of the path */ spt = strchr(spt, '/'); if (spt == NULL) break; /* * skip over duplicate slashes; stop if there're only * trailing slashes left */ next = spt + 1; while (*next == '/') next++; if (*next == '\0') 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 = '/'; spt = next; continue; } /* * the path fails at this point, see if we can create the * needed directory and continue on */ if (mkdir(name, S_IRWXU | S_IRWXG | S_IRWXO) == -1) { if (!ign) syswarn(1, errno, "Unable to mkdir %s", name); *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) == -1) && (lstat(name, &sb) == 0)) { set_pmode(name, ((sb.st_mode & FILEBITS) | S_IRWXU)); add_dir(name, &sb, 1); } *spt = '/'; spt = next; continue; } 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. */ void set_ftime(const char *fnm, const struct timespec *mtimp, const struct timespec *atimp, int frc) { struct timespec tv[2]; tv[0] = *atimp; tv[1] = *mtimp; if (!frc) { /* * if we are not forcing, only set those times the user wants * set. */ if (!patime) tv[0].tv_nsec = UTIME_OMIT; if (!pmtime) tv[1].tv_nsec = UTIME_OMIT; } /* * set the times */ if (utimensat(AT_FDCWD, fnm, tv, AT_SYMLINK_NOFOLLOW) < 0) syswarn(1, errno, "Access/modification time set failed on: %s", fnm); } static void fset_ftime(const char *fnm, int fd, const struct timespec *mtimp, const struct timespec *atimp, int frc) { struct timespec tv[2]; tv[0] = *atimp; tv[1] = *mtimp; if (!frc) { /* * if we are not forcing, only set those times the user wants * set. */ if (!patime) tv[0].tv_nsec = UTIME_OMIT; if (!pmtime) tv[1].tv_nsec = UTIME_OMIT; } /* * set the times */ if (futimens(fd, tv) == -1) 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 (fchownat(AT_FDCWD, fnm, uid, gid, AT_SYMLINK_NOFOLLOW) == -1) { /* * ignore EPERM unless in verbose mode or being run by root. * if running as pax, POSIX requires a warning. */ if (op_mode == OP_PAX || errno != EPERM || vflag || geteuid() == 0) syswarn(1, errno, "Unable to set file uid/gid of %s", fnm); return(-1); } return(0); } int fset_ids(char *fnm, int fd, uid_t uid, gid_t gid) { if (fchown(fd, uid, gid) == -1) { /* * ignore EPERM unless in verbose mode or being run by root. * if running as pax, POSIX requires a warning. */ if (op_mode == OP_PAX || errno != EPERM || vflag || geteuid() == 0) syswarn(1, errno, "Unable to 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 &= ABITS; if (fchmodat(AT_FDCWD, fnm, mode, AT_SYMLINK_NOFOLLOW) == -1) syswarn(1, errno, "Could not set permissions on %s", fnm); } static void fset_pmode(char *fnm, int fd, mode_t mode) { mode &= ABITS; if (fchmod(fd, mode) == -1) syswarn(1, errno, "Could not set permissions on %s", fnm); } /* * set_attr() * Given a DIRDATA, restore the mode and times as indicated, but * only after verifying that it's the directory that we wanted. */ int set_attr(const struct file_times *ft, int force_times, mode_t mode, int do_mode, int in_sig) { struct stat sb; int fd, r; if (!do_mode && !force_times && !patime && !pmtime) return (0); /* * We could legitimately go through a symlink here, * so do *not* use O_NOFOLLOW. The dev+ino check will * protect us from evil. */ fd = open(ft->ft_name, O_RDONLY | O_DIRECTORY); if (fd == -1) { if (!in_sig) syswarn(1, errno, "Unable to restore mode and times" " for directory: %s", ft->ft_name); return (-1); } if (fstat(fd, &sb) == -1) { if (!in_sig) syswarn(1, errno, "Unable to stat directory: %s", ft->ft_name); r = -1; } else if (ft->ft_ino != sb.st_ino || ft->ft_dev != sb.st_dev) { if (!in_sig) paxwarn(1, "Directory vanished before restoring" " mode and times: %s", ft->ft_name); r = -1; } else { /* Whew, it's a match! Is there anything to change? */ if (do_mode && (mode & ABITS) != (sb.st_mode & ABITS)) fset_pmode(ft->ft_name, fd, mode); if (((force_times || patime) && timespeccmp(&ft->ft_atim, &sb.st_atim, !=)) || ((force_times || pmtime) && timespeccmp(&ft->ft_mtim, &sb.st_mtim, !=))) fset_ftime(ft->ft_name, fd, &ft->ft_mtim, &ft->ft_atim, force_times); r = 0; } close(fd); return (r); } /* * 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 zero's 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; /* * 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 = MINIMUM(cnt, *rem); cnt -= wcnt; *rem -= wcnt; if (*isempt) { /* * have not written to this block yet, so we keep * looking for zero's */ 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, 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 -1: strp = &gnu_name_string; break; case -2: strp = &gnu_link_string; break; default: strp = NULL; break; } if (strp) { if (*strp) err(1, "WARNING! Major Internal Error! GNU hack Failing!"); *strp = malloc(wcnt + 1); if (*strp == NULL) { paxwarn(1, "Out of memory"); return(-1); } memcpy(*strp, st, wcnt); (*strp)[wcnt] = '\0'; break; } else if (write(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). */ void 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; /* * move back one byte and write a zero */ if (lseek(fd, -1, SEEK_CUR) < 0) { syswarn(1, errno, "Failed seek on file %s", fname); return; } if (write(fd, blnk, 1) == -1) syswarn(1, errno, "Failed write to file %s", fname); } /* * 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; /* * user wants last access time reset */ if (tflag) fset_ftime(arcn->org_name, *fd, &arcn->sb.st_mtim, &arcn->sb.st_atim, 1); (void)close(*fd); *fd = -1; } /* * 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 = 0; size_t size; u_int32_t crc = 0; char tbuf[FILEBLK]; struct stat sb; if (fd < 0) { /* * hmm, no fd, should never happen. well no crc then. */ arcn->crc = 0; return(0); } if ((size = arcn->sb.st_blksize) > sizeof(tbuf)) size = 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) paxwarn(1, "File changed size %s", arcn->org_name); else if (fstat(fd, &sb) == -1) syswarn(1, errno, "Failed stat on %s", arcn->org_name); else if (timespeccmp(&arcn->sb.st_mtim, &sb.st_mtim, !=)) paxwarn(1, "File %s was modified during read", arcn->org_name); else if (lseek(fd, 0, SEEK_SET) < 0) syswarn(1, errno, "File rewind failed on: %s", arcn->org_name); else { arcn->crc = crc; return(0); } return(-1); }
