/*
 * dpkg - main program for package management
 * archives.c - actions that process archive files, mainly unpack
 *
 * Copyright © 1994,1995 Ian Jackson <ijackson@chiark.greenend.org.uk>
 * Copyright © 2000 Wichert Akkerman <wakkerma@debian.org>
 * Copyright © 2007-2015 Guillem Jover <guillem@debian.org>
 * Copyright © 2011 Linaro Limited
 * Copyright © 2011 Raphaël Hertzog <hertzog@debian.org>
 *
 * This is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#include <config.h>
#include <compat.h>

#include <sys/types.h>
#include <sys/time.h>
#include <sys/stat.h>

#include <errno.h>
#include <string.h>
#include <time.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <obstack.h>
#define obstack_chunk_alloc m_malloc
#define obstack_chunk_free free

#include <dpkg/i18n.h>
#include <dpkg/dpkg.h>
#include <dpkg/dpkg-db.h>
#include <dpkg/pkg.h>
#include <dpkg/path.h>
#include <dpkg/fdio.h>
#include <dpkg/buffer.h>
#include <dpkg/subproc.h>
#include <dpkg/command.h>
#include <dpkg/file.h>
#include <dpkg/treewalk.h>
#include <dpkg/tarfn.h>
#include <dpkg/options.h>
#include <dpkg/triglib.h>
#include <dpkg/db-ctrl.h>
#include <dpkg/db-fsys.h>

#include "main.h"
#include "archives.h"
#include "filters.h"

static inline void
fd_writeback_init(int fd)
{
	/* Ignore the return code as it should be considered equivalent to an
	 * asynchronous hint for the kernel, we are doing an fsync() later on
	 * anyway. */
#if defined(SYNC_FILE_RANGE_WRITE)
	sync_file_range(fd, 0, 0, SYNC_FILE_RANGE_WRITE);
#elif defined(HAVE_POSIX_FADVISE)
	posix_fadvise(fd, 0, 0, POSIX_FADV_DONTNEED);
#endif
}

static struct obstack tar_pool;
static bool tar_pool_init = false;

/**
 * Allocate memory from the tar memory pool.
 */
static void *
tar_pool_alloc(size_t size)
{
	if (!tar_pool_init) {
		obstack_init(&tar_pool);
		tar_pool_init = true;
	}

	/* cppcheck-suppress[nullPointerArithmetic]:
	 * False positive, imported module. */
	return obstack_alloc(&tar_pool, size);
}

/**
 * Free memory from the tar memory pool.
 */
static void
tar_pool_free(void *ptr)
{
	obstack_free(&tar_pool, ptr);
}

/**
 * Release the tar memory pool.
 */
static void
tar_pool_release(void)
{
	if (tar_pool_init) {
		/* cppcheck-suppress[nullPointerArithmetic,pointerLessThanZero]:
		 * False positive, imported module. */
		obstack_free(&tar_pool, NULL);
		tar_pool_init = false;
	}
}

struct fsys_namenode_list *
tar_fsys_namenode_queue_push(struct fsys_namenode_queue *queue,
                            struct fsys_namenode *namenode)
{
	struct fsys_namenode_list *node;

	node = tar_pool_alloc(sizeof(*node));
	node->namenode = namenode;
	node->next = NULL;

	*queue->tail = node;
	queue->tail = &node->next;

	return node;
}

static void
tar_fsys_namenode_queue_pop(struct fsys_namenode_queue *queue,
                           struct fsys_namenode_list **tail_prev,
                           struct fsys_namenode_list *node)
{
	tar_pool_free(node);
	queue->tail = tail_prev;
	*tail_prev = NULL;
}

/**
 * Check if a file or directory will save a package from disappearance.
 *
 * A package can only be saved by a file or directory which is part
 * only of itself - it must be neither part of the new package being
 * installed nor part of any 3rd package (this is important so that
 * shared directories don't stop packages from disappearing).
 */
bool
filesavespackage(struct fsys_namenode_list *file,
                 struct pkginfo *pkgtobesaved,
                 struct pkginfo *pkgbeinginstalled)
{
	struct fsys_node_pkgs_iter *iter;
	struct pkginfo *thirdpkg;

	debug_at(dbg_eachfiledetail, "file '%s' package %s",
	         file->namenode->name, pkg_name(pkgtobesaved, pnaw_always));

	/* If the file is a contended one and it's overridden by either
	 * the package we're considering disappearing or the package
	 * we're installing then they're not actually the same file, so
	 * we can't disappear the package - it is saved by this file. */
	if (file->namenode->divert && file->namenode->divert->useinstead) {
		struct pkgset *divpkgset;

		divpkgset = file->namenode->divert->pkgset;
		if (divpkgset == pkgtobesaved->set ||
		    divpkgset == pkgbeinginstalled->set) {
			debug_at(dbg_eachfiledetail, "... diverted -- save!");
			return true;
		}
	}

	/* Is the file in the package being installed? If so then it can't
	 * save. */
	if (file->namenode->flags & FNNF_NEW_INARCHIVE) {
		debug_at(dbg_eachfiledetail, "... in new archive -- no save");
		return false;
	}

	/* Look for a 3rd package which can take over the file (in case
	 * it's a directory which is shared by many packages. */
	iter = fsys_node_pkgs_iter_new(file->namenode);
	while ((thirdpkg = fsys_node_pkgs_iter_next(iter))) {
		debug_at(dbg_eachfiledetail, "... also in %s",
		         pkg_name(thirdpkg, pnaw_always));

		/* Is this not the package being installed or the one being
		 * checked for disappearance? */
		if (thirdpkg == pkgbeinginstalled || thirdpkg == pkgtobesaved)
			continue;

		/* A Multi-Arch: same package can share files and their
		 * presence in a third package of the same set is not a sign
		 * that we can get rid of it. */
		if (pkgtobesaved->installed.multiarch == PKG_MULTIARCH_SAME &&
		    thirdpkg->set == pkgtobesaved->set)
			continue;

		debug_at(dbg_eachfiledetail, "... is 3rd package");

		/* If !files_list_valid then we have already disappeared this
		 * one, so we should not try to make it take over this shared
		 * directory. */
		if (!thirdpkg->files_list_valid) {
			debug_at(dbg_eachfiledetail, "... already disappeared!");
			continue;
		}

		/* We've found a package that can take this file. */
		debug_at(dbg_eachfiledetail, "... taken -- no save");
		fsys_node_pkgs_iter_free(iter);
		return false;
	}
	fsys_node_pkgs_iter_free(iter);

	debug_at(dbg_eachfiledetail, "... not taken -- save!");
	return true;
}

static void
md5hash_prev_conffile(struct pkginfo *pkg, char *oldhash, const char *oldname,
                      struct fsys_namenode *namenode)
{
	struct pkginfo *otherpkg;
	struct conffile *conff;

	debug(dbg_conffdetail, "tarobject looking for shared conffile %s",
	      namenode->name);

	for (otherpkg = &pkg->set->pkg;
	     otherpkg;
	     otherpkg = otherpkg->arch_next) {
		if (otherpkg == pkg)
			continue;

		/* If we are reinstalling, even if the other package is only
		 * unpacked, we can always make use of the Conffiles hash value
		 * from an initial installation, if that happened at all. */
		if (otherpkg->status <= PKG_STAT_UNPACKED &&
		    dpkg_version_compare(&otherpkg->installed.version,
		                         &otherpkg->configversion) != 0)
			continue;

		for (conff = otherpkg->installed.conffiles;
		     conff;
		     conff = conff->next) {
			if (conffile_is_disappearing(conff))
				continue;
			if (strcmp(conff->name, namenode->name) == 0)
				break;
		}
		if (conff) {
			strcpy(oldhash, conff->hash);
			debug(dbg_conffdetail,
			      "tarobject found shared conffile, from pkg %s (%s); digest=%s",
			      pkg_name(otherpkg, pnaw_always),
			      pkg_status_name(otherpkg), oldhash);
			break;
		}
	}

	/* If no package was found with a valid Conffiles field, we make the
	 * risky assumption that the hash of the current .dpkg-new file is
	 * the one of the previously unpacked package. */
	if (otherpkg == NULL) {
		md5hash(pkg, oldhash, oldname);
		debug(dbg_conffdetail,
		      "tarobject found shared conffile, from disk; digest=%s",
		      oldhash);
	}
}

void
cu_pathname(int argc, void **argv)
{
	path_remove_tree((char*)(argv[0]));
}

int
tarfileread(struct tar_archive *tar, char *buf, int len)
{
	struct tarcontext *tc = (struct tarcontext *)tar->ctx;
	int n;

	n = fd_read(tc->backendpipe, buf, len);
	if (n < 0)
		ohshite(_("error reading from dpkg-deb pipe"));

	return n;
}

static void
tarobject_skip_padding(struct tarcontext *tc, struct tar_entry *te)
{
	struct dpkg_error err;
	size_t remainder;

	remainder = te->size % TARBLKSZ;
	if (remainder == 0)
		return;

	if (fd_skip(tc->backendpipe, TARBLKSZ - remainder, &err) < 0)
		ohshit(_("cannot skip padding for file '%s': %s"),
		       te->name, err.str);
}

static void
tarobject_skip_entry(struct tarcontext *tc, struct tar_entry *ti)
{
	/* We need to advance the tar file to the next object, so read the
	 * file data and set it to oblivion. */
	if (ti->type == TAR_FILETYPE_FILE) {
		struct dpkg_error err;

		if (fd_skip(tc->backendpipe, ti->size, &err) < 0)
			ohshit(_("cannot skip file '%s' (replaced or excluded?) from pipe: %s"),
			       ti->name, err.str);
		tarobject_skip_padding(tc, ti);
	}
}

struct varbuf_state fname_state;
struct varbuf_state fnametmp_state;
struct varbuf_state fnamenew_state;
struct varbuf fnamevb;
struct varbuf fnametmpvb;
struct varbuf fnamenewvb;
struct pkg_deconf_list *deconfigure = NULL;

static time_t currenttime;

static int
does_replace(struct pkginfo *new_pkg, struct pkgbin *new_pkgbin,
             struct pkginfo *old_pkg, struct pkgbin *old_pkgbin)
{
	struct dependency *dep;

	debug_at(dbg_depcon, "new=%s old=%s (%s)",
	         pkgbin_name(new_pkg, new_pkgbin, pnaw_always),
	         pkgbin_name(old_pkg, old_pkgbin, pnaw_always),
	         versiondescribe_c(&old_pkgbin->version, vdew_always));
	for (dep = new_pkgbin->depends; dep; dep = dep->next) {
		if (dep->type != dep_replaces || dep->list->ed != old_pkg->set)
			continue;

		debug_at(dbg_depcondetail, "... found old, version %s",
		         versiondescribe_c(&dep->list->version, vdew_always));

		if (!versionsatisfied(old_pkgbin, dep->list))
			continue;

		/* The test below can only trigger if dep_replaces start having
		 * arch qualifiers different from “any”. */
		if (!archsatisfied(old_pkgbin, dep->list))
			continue;

		debug_at(dbg_depcon, "... yes");
		return true;
	}

	debug_at(dbg_depcon, "... no");
	return false;
}

static void
tarobject_extract(struct tarcontext *tc, struct tar_entry *te,
                  const char *path, struct file_stat *st,
                  struct fsys_namenode *namenode)
{
	static struct varbuf hardlinkfn;
	static int fd;

	struct dpkg_error err;
	struct fsys_namenode *linknode;
	char *newhash;
	int rc;

	switch (te->type) {
	case TAR_FILETYPE_FILE:
		/* We create the file with mode 0 to make sure nobody can do
		 * anything with it until we apply the proper mode, which
		 * might be a statoverride. */
		fd = open(path, O_CREAT | O_EXCL | O_WRONLY, 0);
		if (fd < 0)
			ohshite(_("unable to create '%s' (while processing '%s')"),
			        path, te->name);
		push_cleanup(cu_closefd, ehflag_bombout, 1, &fd);
		debug(dbg_eachfiledetail, "tarobject file open, size=%jd",
		      (intmax_t)te->size);

		/* We try to tell the filesystem how much disk space we are
		 * going to need to let it reduce fragmentation and possibly
		 * improve performance, as we do know the size beforehand. */
		fd_allocate_size(fd, 0, te->size);

		newhash = nfmalloc(MD5HASHLEN + 1);
		if (fd_fd_copy_and_md5(tc->backendpipe, fd, newhash, te->size, &err) < 0)
			ohshit(_("cannot copy extracted data for '%s' to '%s': %s"),
			       te->name, fnamenewvb.buf, err.str);
		namenode->newhash = newhash;
		debug(dbg_eachfiledetail,
		      "tarobject file digest=%s", namenode->newhash);

		tarobject_skip_padding(tc, te);

		fd_writeback_init(fd);

		if (namenode->statoverride)
			debug(dbg_eachfile,
			      "tarobject ... stat override, uid=%d, gid=%d, mode=%04o",
			      namenode->statoverride->uid,
			      namenode->statoverride->gid,
			      namenode->statoverride->mode);
		rc = fchown(fd, st->uid, st->gid);
		if (forcible_nonroot_error(rc))
			ohshite(_("error setting ownership of '%s'"),
			        te->name);
		rc = fchmod(fd, st->mode & ~S_IFMT);
		if (forcible_nonroot_error(rc))
			ohshite(_("error setting permissions of '%s'"),
			        te->name);

		/* Postpone the fsync, to try to avoid massive I/O
		 * degradation. */
		if (!in_force(FORCE_UNSAFE_IO))
			namenode->flags |= FNNF_DEFERRED_FSYNC;

		pop_cleanup(ehflag_normaltidy); /* fd = open(path) */
		if (close(fd))
			ohshite(_("error closing/writing '%s'"), te->name);
		debug(dbg_eachfiledetail, "tarobject file created");
		break;
	case TAR_FILETYPE_FIFO:
		if (mkfifo(path, 0))
			ohshite(_("error creating pipe '%s'"), te->name);
		debug(dbg_eachfiledetail, "tarobject fifo created");
		break;
	case TAR_FILETYPE_CHARDEV:
		if (mknod(path, S_IFCHR, te->dev))
			ohshite(_("error creating device '%s'"), te->name);
		debug(dbg_eachfiledetail, "tarobject chardev created");
		break;
	case TAR_FILETYPE_BLOCKDEV:
		if (mknod(path, S_IFBLK, te->dev))
			ohshite(_("error creating device '%s'"), te->name);
		debug(dbg_eachfiledetail, "tarobject blockdev created");
		break;
	case TAR_FILETYPE_HARDLINK:
		varbuf_set_str(&hardlinkfn, dpkg_fsys_get_dir());
		linknode = fsys_hash_find_node(te->linkname, FHFF_NONE);
		varbuf_add_str(&hardlinkfn,
		               namenodetouse(linknode, tc->pkg, &tc->pkg->available)->name);
		if (linknode->flags & (FNNF_DEFERRED_RENAME | FNNF_NEW_CONFF))
			varbuf_add_str(&hardlinkfn, DPKGNEWEXT);
		if (link(hardlinkfn.buf, path))
			ohshite(_("error creating hard link '%s'"),
			        te->name);
		namenode->newhash = linknode->newhash;
		debug(dbg_eachfiledetail,
		      "tarobject hardlink created, digest=%s",
		      namenode->newhash);
		break;
	case TAR_FILETYPE_SYMLINK:
		/* We've already checked for an existing directory. */
		if (symlink(te->linkname, path))
			ohshite(_("error creating symbolic link '%s'"),
			        te->name);
		debug(dbg_eachfiledetail, "tarobject symlink created");
		break;
	case TAR_FILETYPE_DIR:
		/* We've already checked for an existing directory. */
		if (mkdir(path, 0))
			ohshite(_("error creating directory '%s'"),
			        te->name);
		debug(dbg_eachfiledetail, "tarobject directory created");
		break;
	default:
		internerr("unknown tar type '%d', but already checked",
		          te->type);
	}
}

static void
tarobject_hash(struct tarcontext *tc, struct tar_entry *te,
               struct fsys_namenode *namenode)
{
	if (te->type == TAR_FILETYPE_FILE) {
		struct dpkg_error err;
		char *newhash;

		newhash = nfmalloc(MD5HASHLEN + 1);
		if (fd_md5(tc->backendpipe, newhash, te->size, &err) < 0)
			ohshit(_("cannot compute MD5 digest for file '%s' in tar archive: %s"),
			       te->name, err.str);
		tarobject_skip_padding(tc, te);

		namenode->newhash = newhash;
		debug(dbg_eachfiledetail, "tarobject file digest=%s",
		      namenode->newhash);
	} else if (te->type == TAR_FILETYPE_HARDLINK) {
		struct fsys_namenode *linknode;

		linknode = fsys_hash_find_node(te->linkname, FHFF_NONE);
		namenode->newhash = linknode->newhash;
		debug(dbg_eachfiledetail, "tarobject hardlink digest=%s",
		      namenode->newhash);
	}
}

static void
tarobject_set_mtime(struct tar_entry *te, const char *path)
{
	struct timeval tv[2];

	tv[0].tv_sec = currenttime;
	tv[0].tv_usec = 0;
	tv[1].tv_sec = te->mtime;
	tv[1].tv_usec = 0;

	if (te->type == TAR_FILETYPE_SYMLINK) {
#ifdef HAVE_LUTIMES
		if (lutimes(path, tv) && errno != ENOSYS)
			ohshite(_("error setting timestamps of '%s'"),
			        path);
#endif
	} else {
		if (utimes(path, tv))
			ohshite(_("error setting timestamps of '%s'"),
			        path);
	}
}

static void
tarobject_set_perms(struct tar_entry *te, const char *path, struct file_stat *st)
{
	int rc;

	if (te->type == TAR_FILETYPE_FILE)
		/* Already handled using the file descriptor. */
		return;

	if (te->type == TAR_FILETYPE_SYMLINK) {
		rc = lchown(path, st->uid, st->gid);
		if (forcible_nonroot_error(rc))
			ohshite(_("error setting ownership of symlink '%s'"),
			        path);
	} else {
		rc = chown(path, st->uid, st->gid);
		if (forcible_nonroot_error(rc))
			ohshite(_("error setting ownership of '%s'"), path);
		rc = chmod(path, st->mode & ~S_IFMT);
		if (forcible_nonroot_error(rc))
			ohshite(_("error setting permissions of '%s'"),
			        path);
	}
}

static void
tarobject_set_se_context(const char *matchpath, const char *path, mode_t mode)
{
	dpkg_selabel_set_context(matchpath, path, mode);
}

static void
tarobject_matches(struct tarcontext *tc,
                  const char *fn_old, struct stat *stab, char *oldhash,
                  const char *fn_new, struct tar_entry *te,
                  struct fsys_namenode *namenode)
{
	struct varbuf linkname = VARBUF_INIT;
	ssize_t linksize;
	bool linkmatch;

	debug(dbg_eachfiledetail, "tarobject matches on-disk object?");

	switch (te->type) {
	case TAR_FILETYPE_DIR:
		/* Nothing to check for a new directory. */
		return;
	case TAR_FILETYPE_SYMLINK:
		/* TODO: Refactor symlink matching. */
		/* Symlinks to existing dirs have already been dealt with, only
		 * remain real symlinks where we can compare the target. */
		if (!S_ISLNK(stab->st_mode))
			break;
		linksize = file_readlink(fn_old, &linkname, stab->st_size);
		if (linksize < 0)
			ohshite(_("unable to read link '%s'"), fn_old);
		else if (linksize > stab->st_size)
			ohshit(_("symbolic link '%s' size has changed from %jd to %zd"),
			       fn_old, (intmax_t)stab->st_size, linksize);
		else if (linksize < stab->st_size)
			warning(_("symbolic link '%s' size has changed from %jd to %zd"),
			       fn_old, (intmax_t)stab->st_size, linksize);
		linkmatch = strcmp(linkname.buf, te->linkname) == 0;
		varbuf_destroy(&linkname);
		if (linkmatch)
			return;
		break;
	case TAR_FILETYPE_CHARDEV:
		if (S_ISCHR(stab->st_mode) && stab->st_rdev == te->dev)
			return;
		break;
	case TAR_FILETYPE_BLOCKDEV:
		if (S_ISBLK(stab->st_mode) && stab->st_rdev == te->dev)
			return;
		break;
	case TAR_FILETYPE_FIFO:
		if (S_ISFIFO(stab->st_mode))
			return;
		break;
	case TAR_FILETYPE_HARDLINK:
		/* Fall through. */
	case TAR_FILETYPE_FILE:
		/* Only check metadata for non-conffiles. */
		if (!(namenode->flags & FNNF_NEW_CONFF) &&
		    !(S_ISREG(stab->st_mode) && te->size == stab->st_size))
			break;
		if (strcmp(oldhash, namenode->newhash) == 0)
			return;
		break;
	default:
		internerr("unknown tar type '%d', but already checked",
		          te->type);
	}

	forcibleerr(FORCE_OVERWRITE,
	            _("trying to overwrite shared '%s', which is different "
	              "from other instances of package %s"),
	            namenode->name, pkg_name(tc->pkg, pnaw_nonambig));
}

void
setupfnamevbs(const char *filename)
{
	varbuf_rollback(&fname_state);
	varbuf_add_str(&fnamevb, filename);

	varbuf_rollback(&fnametmp_state);
	varbuf_add_str(&fnametmpvb, filename);
	varbuf_add_str(&fnametmpvb, DPKGTEMPEXT);

	varbuf_rollback(&fnamenew_state);
	varbuf_add_str(&fnamenewvb, filename);
	varbuf_add_str(&fnamenewvb, DPKGNEWEXT);

	debug_at(dbg_eachfiledetail, "main='%s' tmp='%s' new='%s'",
	         fnamevb.buf, fnametmpvb.buf, fnamenewvb.buf);
}

static bool
linktosameexistingdir(const struct tar_entry *ti, const char *fname,
                      struct varbuf *symlinkfn)
{
	struct stat oldstab, newstab;
	int statr;

	statr = stat(fname, &oldstab);
	if (statr) {
		if (!(errno == ENOENT || errno == ELOOP || errno == ENOTDIR))
			ohshite(_("failed to stat (dereference) existing symlink '%s'"),
			        fname);
		return false;
	}
	if (!S_ISDIR(oldstab.st_mode))
		return false;

	/* But is it to the same dir? */
	if (ti->linkname[0] == '/') {
		varbuf_set_str(symlinkfn, dpkg_fsys_get_dir());
	} else {
		const char *lastslash;

		lastslash = strrchr(fname, '/');
		if (lastslash == NULL)
			internerr("tar entry filename '%s' does not contain '/'",
			          fname);
		varbuf_set_buf(symlinkfn, fname, (lastslash - fname) + 1);
	}
	varbuf_add_str(symlinkfn, ti->linkname);

	statr = stat(symlinkfn->buf, &newstab);
	if (statr) {
		if (!(errno == ENOENT || errno == ELOOP || errno == ENOTDIR))
			ohshite(_("failed to stat (dereference) proposed new symlink target"
			          " '%s' for symlink '%s'"),
			        symlinkfn->buf, fname);
		return false;
	}
	if (!S_ISDIR(newstab.st_mode))
		return false;
	if (newstab.st_dev != oldstab.st_dev ||
	    newstab.st_ino != oldstab.st_ino)
		return false;
	return true;
}

/* TODO: Refactor to reduce nesting levels. */
int
tarobject(struct tar_archive *tar, struct tar_entry *ti)
{
	static struct varbuf conffderefn, symlinkfn;
	const char *usename;
	struct fsys_namenode *namenode, *usenode;

	struct conffile *conff;
	struct tarcontext *tc = tar->ctx;
	bool existingdir, keepexisting;
	bool refcounting;
	char oldhash[MD5HASHLEN + 1];
	int statr;
	struct stat stab, stabtmp;
	struct file_stat nodestat;
	struct fsys_namenode_list *nifd, **oldnifd;
	struct pkgset *divpkgset;
	struct pkginfo *otherpkg;

	tar_entry_update_from_system(ti);

	/* Perform some sanity checks on the tar entry. */
	if (strchr(ti->name, '\n'))
		ohshit(_("newline not allowed in archive object name '%s'"),
		       ti->name);

	namenode = fsys_hash_find_node(ti->name, FHFF_NONE);

	if (namenode->flags & FNNF_RM_CONFF_ON_UPGRADE)
		ohshit(_("conffile '%s' marked for removal on upgrade, shipped in package"),
		       ti->name);

	/* Append to list of files.
	 * The trailing ‘/’ put on the end of names in tarfiles has already
	 * been stripped by tar_extractor(). */
	oldnifd = tc->newfiles_queue->tail;
	nifd = tar_fsys_namenode_queue_push(tc->newfiles_queue, namenode);
	nifd->namenode->flags |= FNNF_NEW_INARCHIVE;

	debug(dbg_eachfile,
	      "tarobject parsed ti->name='%s' mode=%lo owner=%u:%u type=%d(%c)"
	      " ti->linkname='%s' namenode='%s' flags=%o instead='%s'",
	      ti->name, (long)ti->stat.mode,
	      (unsigned)ti->stat.uid, (unsigned)ti->stat.gid,
	      ti->type,
	      ti->type >= '0' && ti->type <= '6' ? "-hlcbdp"[ti->type - '0'] : '?',
	      ti->linkname,
	      nifd->namenode->name, nifd->namenode->flags,
	      nifd->namenode->divert && nifd->namenode->divert->useinstead
	      ? nifd->namenode->divert->useinstead->name : "<none>");

	if (nifd->namenode->divert && nifd->namenode->divert->camefrom) {
		divpkgset = nifd->namenode->divert->pkgset;

		if (divpkgset) {
			forcibleerr(FORCE_OVERWRITE_DIVERTED,
			            _("trying to overwrite '%s', which is the "
			              "diverted version of '%s' (package: %s)"),
			            nifd->namenode->name,
			            nifd->namenode->divert->camefrom->name,
			            divpkgset->name);
		} else {
			forcibleerr(FORCE_OVERWRITE_DIVERTED,
			            _("trying to overwrite '%s', which is the "
			              "diverted version of '%s'"),
			            nifd->namenode->name,
			            nifd->namenode->divert->camefrom->name);
		}
	}

	if (nifd->namenode->statoverride) {
		nodestat = *nifd->namenode->statoverride;
		nodestat.mode |= ti->stat.mode & S_IFMT;
	} else {
		nodestat = ti->stat;
	}

	usenode = namenodetouse(nifd->namenode, tc->pkg, &tc->pkg->available);
	usename = usenode->name;

	trig_file_activate(usenode, tc->pkg);

	if (nifd->namenode->flags & FNNF_NEW_CONFF) {
		/* If it's a conffile we have to extract it next to the
		 * installed version (i.e. we do the usual link-following). */
		if (conffderef(tc->pkg, &conffderefn, usename))
			usename = conffderefn.buf;
		debug(dbg_conff, "tarobject FNNF_NEW_CONFF deref='%s'",
		      usename);
	}

	setupfnamevbs(usename);

	statr = lstat(fnamevb.buf, &stab);
	if (statr) {
		/* The lstat failed. */
		if (errno != ENOENT && errno != ENOTDIR)
			ohshite(_("unable to stat '%s' (which was about to be installed)"),
			        ti->name);

		/*
		 * OK, so it doesn't exist.
		 *
		 * However, it's possible that we were in the middle of some
		 * other backup/restore operation and were rudely interrupted.
		 * So, we see if we have .dpkg-tmp, and if so we restore it.
		 */
		if (rename(fnametmpvb.buf, fnamevb.buf)) {
			/* Trying to remove a directory or a file on a
			 * read-only filesystem, even if non-existent,
			 * always returns EROFS. */
			if (errno == EROFS) {
				/* If the file does not exist the access()
				 * function will remap the EROFS into an ENOENT,
				 * otherwise restore EROFS to fail with that. */
				if (access(fnametmpvb.buf, F_OK) == 0)
					errno = EROFS;
			}

			if (errno != ENOENT && errno != ENOTDIR)
				ohshite(_("unable to clean up mess surrounding '%s' "
				          "before installing another version"),
				        ti->name);
			debug(dbg_eachfiledetail,
			      "tarobject %s nonexistent as %s",
			      ti->name, fnamevb.buf);
		} else {
			debug(dbg_eachfiledetail,
			      "tarobject %s restored tmp to main %s",
			      ti->name, fnamevb.buf);
			statr = lstat(fnamevb.buf, &stab);
			if (statr)
				ohshite(_("unable to stat restored '%s' "
				          "before installing another version"),
				        ti->name);
		}
	} else {
		debug(dbg_eachfiledetail, "tarobject %s already exists as %s",
		      ti->name, fnamevb.buf);
	}

	/* Check to see if it's a directory or link to one and we don't need to
	 * do anything. This has to be done now so that we don't die due to
	 * a file overwriting conflict. */
	existingdir = false;
	switch (ti->type) {
	case TAR_FILETYPE_SYMLINK:
		/* If it's already an existing directory, do nothing. */
		if (!statr && S_ISDIR(stab.st_mode)) {
			debug(dbg_eachfiledetail,
			      "tarobject %s symlink exists as directory %s",
			      ti->name, fnamevb.buf);
			existingdir = true;
		} else if (!statr && S_ISLNK(stab.st_mode)) {
			if (linktosameexistingdir(ti, fnamevb.buf, &symlinkfn))
				existingdir = true;
		}
		break;
	case TAR_FILETYPE_DIR:
		/* If it's already an existing directory, do nothing. */
		if (!stat(fnamevb.buf, &stabtmp) && S_ISDIR(stabtmp.st_mode)) {
			debug(dbg_eachfiledetail,
			      "tarobject %s directory exists as %s",
			      ti->name, fnamevb.buf);
			existingdir = true;
		}
		break;
	case TAR_FILETYPE_FILE:
	case TAR_FILETYPE_CHARDEV:
	case TAR_FILETYPE_BLOCKDEV:
	case TAR_FILETYPE_FIFO:
	case TAR_FILETYPE_HARDLINK:
		break;
	default:
		ohshit(_("archive contained object '%s' of unknown type 0x%x"),
		       ti->name, ti->type);
	}

	keepexisting = false;
	refcounting = false;
	if (!existingdir) {
		struct fsys_node_pkgs_iter *iter;

		iter = fsys_node_pkgs_iter_new(nifd->namenode);
		while ((otherpkg = fsys_node_pkgs_iter_next(iter))) {
			if (otherpkg == tc->pkg)
				continue;
			debug(dbg_eachfile, "tarobject ... found in %s",
			      pkg_name(otherpkg, pnaw_always));

			/* A pkgset can share files between its instances.
			 * Overwriting is allowed when they are not getting
			 * in sync, otherwise the file content must match
			 * the installed file. */
			if (otherpkg->set == tc->pkg->set &&
			    otherpkg->installed.multiarch == PKG_MULTIARCH_SAME &&
			    tc->pkg->available.multiarch == PKG_MULTIARCH_SAME) {
				if (statr == 0 && tc->pkgset_getting_in_sync)
					refcounting = true;

				debug(dbg_eachfiledetail,
				      "tarobject ... shared with %s %s (syncing=%d)",
				      pkg_name(otherpkg, pnaw_always),
				      versiondescribe_c(&otherpkg->installed.version, vdew_nonambig),
				      tc->pkgset_getting_in_sync);
				continue;
			}

			if (nifd->namenode->divert &&
			    nifd->namenode->divert->useinstead) {
				/* Right, so we may be diverting this file.
				 * This makes the conflict OK iff one of us is
				 * the diverting package (we don't need to
				 * check for both being the diverting package,
				 * obviously). */
				divpkgset = nifd->namenode->divert->pkgset;

				debug(dbg_eachfile,
				      "tarobject ... diverted, divpkgset=%s",
				      divpkgset ? divpkgset->name : "<none>");

				if (otherpkg->set == divpkgset ||
				    tc->pkg->set == divpkgset)
					continue;
			}

			/* If the new object is a directory and the previous
			 * object does not exist assume it's also a directory
			 * and skip further checks.
			 * XXX: Ideally with more information about the
			 * installed files we could perform more clever
			 * checks. */
			if (statr != 0 && ti->type == TAR_FILETYPE_DIR) {
				debug(dbg_eachfile,
				      "tarobject ... assuming shared directory");
				continue;
			}

			ensure_package_clientdata(otherpkg);

			/* Nope? Hmm, file conflict, perhaps. Check Replaces. */
			switch (otherpkg->clientdata->replacingfilesandsaid) {
			case 2:
				keepexisting = true;
				/* Fall through. */
			case 1:
				continue;
			}

			/* Is the package with the conflicting file in the
			 * “config files only” state? If so it must be a
			 * config file and we can silently take it over. */
			if (otherpkg->status == PKG_STAT_CONFIGFILES)
				continue;

			/* Perhaps we're removing a conflicting package? */
			if (otherpkg->clientdata->istobe == PKG_ISTOBE_REMOVE)
				continue;

			/* Is the file an obsolete conffile in the other package
			 * and a conffile in the new package? */
			if ((nifd->namenode->flags & FNNF_NEW_CONFF) &&
			    !statr && S_ISREG(stab.st_mode)) {
				for (conff = otherpkg->installed.conffiles;
				     conff;
				     conff = conff->next) {
					if (!(conff->flags & CONFFILE_OBSOLETE))
						continue;
					if (strcmp(conff->name, nifd->namenode->name) == 0)
						break;
				}
				if (conff) {
					debug(dbg_eachfiledetail,
					      "tarobject other's obsolete conffile");
					/* process_archive() will have copied
					 * its hash already. */
					continue;
				}
			}

			if (does_replace(tc->pkg, &tc->pkg->available,
			                 otherpkg, &otherpkg->installed)) {
				printf(_("Replacing files in old package %s (%s) ...\n"),
				       pkg_name(otherpkg, pnaw_nonambig),
				       versiondescribe(&otherpkg->installed.version, vdew_nonambig));
				otherpkg->clientdata->replacingfilesandsaid = 1;
			} else if (does_replace(otherpkg, &otherpkg->installed,
			                        tc->pkg, &tc->pkg->available)) {
				printf(_("Replaced by files in installed package %s (%s) ...\n"),
				       pkg_name(otherpkg, pnaw_nonambig),
				       versiondescribe(&otherpkg->installed.version, vdew_nonambig));
				otherpkg->clientdata->replacingfilesandsaid = 2;
				nifd->namenode->flags &= ~FNNF_NEW_INARCHIVE;
				keepexisting = true;
			} else {
				/* At this point we are replacing something without a Replaces. */
				if (!statr && S_ISDIR(stab.st_mode)) {
					forcibleerr(FORCE_OVERWRITE_DIR,
					            _("trying to overwrite directory '%s' "
					              "in package %s (%s) with nondirectory"),
					            nifd->namenode->name,
					            pkg_name(otherpkg, pnaw_nonambig),
					            versiondescribe(&otherpkg->installed.version,
					                            vdew_nonambig));
				} else {
					forcibleerr(FORCE_OVERWRITE,
					            _("trying to overwrite '%s', "
					              "which is also in package %s (%s)"),
					            nifd->namenode->name,
					            pkg_name(otherpkg, pnaw_nonambig),
					            versiondescribe(&otherpkg->installed.version,
					                            vdew_nonambig));
				}
			}
		}
		fsys_node_pkgs_iter_free(iter);
	}

	if (keepexisting) {
		if (nifd->namenode->flags & FNNF_NEW_CONFF)
			nifd->namenode->flags |= FNNF_OBS_CONFF;
		tar_fsys_namenode_queue_pop(tc->newfiles_queue, oldnifd, nifd);
		tarobject_skip_entry(tc, ti);

		return 0;
	}

	if (filter_should_skip(ti)) {
		nifd->namenode->flags &= ~FNNF_NEW_INARCHIVE;
		nifd->namenode->flags |= FNNF_FILTERED;
		tarobject_skip_entry(tc, ti);

		return 0;
	}

	if (existingdir)
		return 0;

	/* Compute the hash of the previous object, before we might replace it
	 * with the new version on forced overwrites. */
	if (refcounting) {
		debug(dbg_eachfiledetail,
		      "tarobject computing on-disk file '%s' digest, refcounting",
		      fnamevb.buf);
		if (nifd->namenode->flags & FNNF_NEW_CONFF) {
			md5hash_prev_conffile(tc->pkg, oldhash, fnamenewvb.buf,
			                      nifd->namenode);
		} else if (S_ISREG(stab.st_mode)) {
			md5hash(tc->pkg, oldhash, fnamevb.buf);
		} else {
			strcpy(oldhash, EMPTYHASHFLAG);
		}
	}

	if (refcounting && !in_force(FORCE_OVERWRITE)) {
		/* If we are not forced to overwrite the path and are
		 * refcounting, just compute the hash w/o extracting
		 * the object. */
		tarobject_hash(tc, ti, nifd->namenode);
	} else {
		/* Now, at this stage we want to make sure neither of
		 * .dpkg-new and .dpkg-tmp are hanging around. */
		path_remove_tree(fnamenewvb.buf);
		path_remove_tree(fnametmpvb.buf);

		/* Now we start to do things that we need to be able to undo
		 * if something goes wrong. Watch out for the CLEANUP comments
		 * to keep an eye on what's installed on the disk at each
		 * point. */
		push_cleanup(cu_installnew, ~ehflag_normaltidy,
		             1, nifd->namenode);

		/*
		 * CLEANUP: Now we either have the old file on the disk, or
		 * not, in its original filename.
		 */

		/* Extract whatever it is as .dpkg-new ... */
		tarobject_extract(tc, ti, fnamenewvb.buf, &nodestat,
		                  nifd->namenode);
	}

	/* For shared files, check now if the object matches. */
	if (refcounting)
		tarobject_matches(tc, fnamevb.buf, &stab, oldhash,
		                      fnamenewvb.buf, ti, nifd->namenode);

	/* If we didn't extract anything, there's nothing else to do. */
	if (refcounting && !in_force(FORCE_OVERWRITE))
		return 0;

	tarobject_set_perms(ti, fnamenewvb.buf, &nodestat);
	tarobject_set_mtime(ti, fnamenewvb.buf);
	tarobject_set_se_context(fnamevb.buf, fnamenewvb.buf, nodestat.mode);

	/*
	 * CLEANUP: Now we have extracted the new object in .dpkg-new (or,
	 * if the file already exists as a directory and we were trying to
	 * extract a directory or symlink, we returned earlier, so we don't
	 * need to worry about that here).
	 *
	 * The old file is still in the original filename,
	 */

	/* First, check to see if it's a conffile. If so we don't install
	 * it now - we leave it in .dpkg-new for --configure to take care of. */
	if (nifd->namenode->flags & FNNF_NEW_CONFF) {
		debug(dbg_conffdetail, "tarobject conffile extracted");
		nifd->namenode->flags |= FNNF_ELIDE_OTHER_LISTS;

		return 0;
	}

	/* Now we move the old file out of the way, the backup file will
	 * be deleted later. */
	if (statr) {
		/* Don't try to back it up if it didn't exist. */
		debug(dbg_eachfiledetail, "tarobject new - no backup");
	} else {
		if (ti->type == TAR_FILETYPE_DIR || S_ISDIR(stab.st_mode)) {
			/* One of the two is a directory - can't do atomic
			 * install. */
			debug(dbg_eachfiledetail,
			      "tarobject directory, nonatomic");
			nifd->namenode->flags |= FNNF_NO_ATOMIC_OVERWRITE;
			if (rename(fnamevb.buf, fnametmpvb.buf))
				ohshite(_("unable to move aside '%s' to install new version"),
				        ti->name);
		} else if (S_ISLNK(stab.st_mode)) {
			ssize_t linksize;
			int rc;

			/* We can't make a symlink with two hardlinks, so
			 * we'll have to copy it. (Pretend that making a copy
			 * of a symlink is the same as linking to it.) */
			linksize = file_readlink(fnamevb.buf, &symlinkfn, stab.st_size);
			if (linksize < 0)
				ohshite(_("unable to read link '%s'"),
				        ti->name);
			else if (linksize > stab.st_size)
				ohshit(_("symbolic link '%s' size has changed from %jd to %zd"),
				       fnamevb.buf, (intmax_t)stab.st_size, linksize);
			else if (linksize < stab.st_size)
				warning(_("symbolic link '%s' size has changed from %jd to %zd"),
				       fnamevb.buf, (intmax_t)stab.st_size, linksize);
			if (symlink(symlinkfn.buf, fnametmpvb.buf))
				ohshite(_("unable to make backup symlink for '%s'"),
				        ti->name);
			rc = lchown(fnametmpvb.buf, stab.st_uid, stab.st_gid);
			if (forcible_nonroot_error(rc))
				ohshite(_("unable to chown backup symlink for '%s'"),
				        ti->name);
			tarobject_set_se_context(fnamevb.buf, fnametmpvb.buf,
			                         stab.st_mode);
		} else {
			debug(dbg_eachfiledetail, "tarobject nondirectory, 'link' backup");
			if (link(fnamevb.buf, fnametmpvb.buf))
				ohshite(_("unable to make backup link of '%s' before installing new version"),
				        ti->name);
		}
	}

	/*
	 * CLEANUP: Now the old file is in .dpkg-tmp, and the new file is still
	 * in .dpkg-new.
	 */

	if (ti->type == TAR_FILETYPE_FILE ||
	    ti->type == TAR_FILETYPE_HARDLINK ||
	    ti->type == TAR_FILETYPE_SYMLINK) {
		nifd->namenode->flags |= FNNF_DEFERRED_RENAME;

		debug(dbg_eachfiledetail,
		      "tarobject done and installation deferred");
	} else {
		if (rename(fnamenewvb.buf, fnamevb.buf))
			ohshite(_("unable to install new version of '%s'"),
			        ti->name);

		/*
		 * CLEANUP: Now the new file is in the destination file, and the
		 * old file is in .dpkg-tmp to be cleaned up later. We now need
		 * to take a different attitude to cleanup, because we need to
		 * remove the new file.
		 */

		nifd->namenode->flags |= FNNF_PLACED_ON_DISK;
		nifd->namenode->flags |= FNNF_ELIDE_OTHER_LISTS;

		debug(dbg_eachfiledetail, "tarobject done and installed");
	}

	return 0;
}

#if defined(SYNC_FILE_RANGE_WAIT_BEFORE)
static void
tar_writeback_barrier(struct fsys_namenode_list *files, struct pkginfo *pkg)
{
	struct fsys_namenode_list *cfile;

	for (cfile = files; cfile; cfile = cfile->next) {
		struct fsys_namenode *usenode;
		int fd;

		if (!(cfile->namenode->flags & FNNF_DEFERRED_FSYNC))
			continue;

		usenode = namenodetouse(cfile->namenode, pkg, &pkg->available);

		setupfnamevbs(usenode->name);

		fd = open(fnamenewvb.buf, O_WRONLY);
		if (fd < 0)
			ohshite(_("unable to open '%s'"), fnamenewvb.buf);
		/* Ignore the return code as it should be considered equivalent
		 * to an asynchronous hint for the kernel, we are doing an
		 * fsync() later on anyway. */
		sync_file_range(fd, 0, 0, SYNC_FILE_RANGE_WAIT_BEFORE);
		if (close(fd))
			ohshite(_("error closing/writing '%s'"),
			        fnamenewvb.buf);
	}
}
#else
static void
tar_writeback_barrier(struct fsys_namenode_list *files, struct pkginfo *pkg)
{
}
#endif

void
tar_deferred_extract(struct fsys_namenode_list *files, struct pkginfo *pkg)
{
	struct fsys_namenode_list *cfile;
	struct fsys_namenode *usenode;

	tar_writeback_barrier(files, pkg);

	for (cfile = files; cfile; cfile = cfile->next) {
		debug(dbg_eachfile, "deferred extract of '%s'?",
		      cfile->namenode->name);

		if (!(cfile->namenode->flags & FNNF_DEFERRED_RENAME))
			continue;

		usenode = namenodetouse(cfile->namenode, pkg, &pkg->available);

		setupfnamevbs(usenode->name);

		if (cfile->namenode->flags & FNNF_DEFERRED_FSYNC) {
			int fd;

			debug(dbg_eachfiledetail,
			      "deferred extract needs fsync");

			fd = open(fnamenewvb.buf, O_WRONLY);
			if (fd < 0)
				ohshite(_("unable to open '%s'"),
				        fnamenewvb.buf);
			if (fsync(fd))
				ohshite(_("unable to sync file '%s'"),
				        fnamenewvb.buf);
			if (close(fd))
				ohshite(_("error closing/writing '%s'"),
				        fnamenewvb.buf);

			cfile->namenode->flags &= ~FNNF_DEFERRED_FSYNC;
		}

		debug(dbg_eachfiledetail, "deferred extract needs rename");

		if (rename(fnamenewvb.buf, fnamevb.buf))
			ohshite(_("unable to install new version of '%s'"),
			        cfile->namenode->name);

		cfile->namenode->flags &= ~FNNF_DEFERRED_RENAME;

		/*
		 * CLEANUP: Now the new file is in the destination file, and the
		 * old file is in .dpkg-tmp to be cleaned up later. We now need
		 * to take a different attitude to cleanup, because we need to
		 * remove the new file.
		 */

		cfile->namenode->flags |= FNNF_PLACED_ON_DISK;
		cfile->namenode->flags |= FNNF_ELIDE_OTHER_LISTS;

		debug(dbg_eachfiledetail,
		      "deferred extract done and installed");
	}
}

void
enqueue_deconfigure(struct pkginfo *pkg, struct pkginfo *pkg_removal,
                    enum pkgwant reason)
{
	struct pkg_deconf_list *newdeconf;

	ensure_package_clientdata(pkg);
	pkg->clientdata->istobe = PKG_ISTOBE_DECONFIGURE;
	newdeconf = m_malloc(sizeof(*newdeconf));
	newdeconf->next = deconfigure;
	newdeconf->pkg = pkg;
	newdeconf->pkg_removal = pkg_removal;
	newdeconf->reason = reason;
	deconfigure = newdeconf;
}

void
clear_deconfigure_queue(void)
{
	struct pkg_deconf_list *deconf, *deconf_next;

	for (deconf = deconfigure; deconf; deconf = deconf_next) {
		deconf_next = deconf->next;
		free(deconf);
	}
	deconfigure = NULL;
}

/**
 * Try if we can deconfigure the package for installation and queue it if so.
 *
 * This function gets called in the Breaks context, when trying to install
 * a package that might require another to be deconfigured to be able to
 * proceed.
 *
 * First checks whether the pdep is forced.
 *
 * @retval 0 Not possible (why is printed).
 * @retval 1 Deconfiguration queued ok (no message printed).
 * @retval 2 Forced (no deconfiguration needed, why is printed).
 */
static int
try_deconfigure_can(struct pkginfo *pkg, struct deppossi *pdep,
                    struct pkginfo *pkg_install, const char *why)
{
	if (force_breaks(pdep)) {
		warning(_("ignoring dependency problem with installation of %s:\n%s"),
		        pkgbin_name(pkg_install, &pkg->available, pnaw_nonambig),
		        why);
		return 2;
	} else if (f_autodeconf) {
		enqueue_deconfigure(pkg, NULL, PKG_WANT_INSTALL);
		return 1;
	} else {
		notice(_("no, cannot proceed with installation of %s "
		         "(--auto-deconfigure will help):\n%s"),
		       pkgbin_name(pkg_install, &pkg->available, pnaw_nonambig),
		       why);
		return 0;
	}
}

/**
 * Try if we can deconfigure the package for removal and queue it if so.
 *
 * This function gets called in the Conflicts+Depends context, when trying
 * to install a package that might require another to be fully removed to
 * be able to proceed.
 *
 * First checks whether the pdep is forced, then if auto-configure is enabled
 * we make sure Essential and Protected are not allowed to be removed unless
 * forced.
 *
 * @retval 0 Not possible (why is printed).
 * @retval 1 Deconfiguration queued ok (no message printed).
 * @retval 2 Forced (no deconfiguration needed, why is printed).
 */
static int
try_remove_can(struct deppossi *pdep,
               struct pkginfo *pkg_removal, const char *why)
{
	struct pkginfo *pkg = pdep->up->up;

	if (force_depends(pdep)) {
		warning(_("ignoring dependency problem with removal of %s:\n%s"),
		        pkg_name(pkg_removal, pnaw_nonambig), why);
		return 2;
	} else if (f_autodeconf) {
		if (pkg->installed.essential) {
			if (in_force(FORCE_REMOVE_ESSENTIAL)) {
				warning(_("considering deconfiguration of essential\n"
				          " package %s, to enable removal of %s"),
				        pkg_name(pkg, pnaw_nonambig),
				        pkg_name(pkg_removal, pnaw_nonambig));
			} else {
				notice(_("no, %s is essential, will not deconfigure\n"
				         " it in order to enable removal of %s"),
				       pkg_name(pkg, pnaw_nonambig),
				       pkg_name(pkg_removal, pnaw_nonambig));
				return 0;
			}
		}
		if (pkg->installed.is_protected) {
			if (in_force(FORCE_REMOVE_PROTECTED)) {
				warning(_("considering deconfiguration of protected\n"
				          " package %s, to enable removal of %s"),
				        pkg_name(pkg, pnaw_nonambig),
				        pkg_name(pkg_removal, pnaw_nonambig));
			} else {
				notice(_("no, %s is protected, will not deconfigure\n"
				         " it in order to enable removal of %s"),
				       pkg_name(pkg, pnaw_nonambig),
				       pkg_name(pkg_removal, pnaw_nonambig));
				return 0;
			}
		}

		enqueue_deconfigure(pkg, pkg_removal, PKG_WANT_DEINSTALL);

		return 1;
	} else {
		notice(_("no, cannot proceed with removal of %s "
		         "(--auto-deconfigure will help):\n%s"),
		       pkg_name(pkg_removal, pnaw_nonambig), why);
		return 0;
	}
}

void
check_breaks(struct dependency *dep, struct pkginfo *pkg, const char *pfilename)
{
	struct pkginfo *fixbydeconf;
	struct varbuf why = VARBUF_INIT;
	int ok;

	fixbydeconf = NULL;
	if (depisok(dep, &why, &fixbydeconf, NULL, false)) {
		varbuf_destroy(&why);
		return;
	}

	if (fixbydeconf && f_autodeconf) {
		ensure_package_clientdata(fixbydeconf);

		if (fixbydeconf->clientdata->istobe != PKG_ISTOBE_NORMAL)
			internerr("package %s being fixed by deconf is not to be normal, "
			          "is to be %d",
			          pkg_name(pkg, pnaw_always),
			          fixbydeconf->clientdata->istobe);

		notice(_("considering deconfiguration of %s, "
		         "which would be broken by installation of %s ..."),
		       pkg_name(fixbydeconf, pnaw_nonambig),
		       pkgbin_name(pkg, &pkg->available, pnaw_nonambig));

		ok = try_deconfigure_can(fixbydeconf, dep->list, pkg,
		                         varbuf_str(&why));
		if (ok == 1) {
			notice(_("yes, will deconfigure %s (broken by %s)"),
			       pkg_name(fixbydeconf, pnaw_nonambig),
			       pkgbin_name(pkg, &pkg->available, pnaw_nonambig));
		}
	} else {
		notice(_("regarding %s containing %s:\n%s"), pfilename,
		       pkgbin_name(pkg, &pkg->available, pnaw_nonambig),
		       varbuf_str(&why));
		ok = 0;
	}
	varbuf_destroy(&why);
	if (ok > 0)
		return;

	if (force_breaks(dep->list)) {
		warning(_("ignoring breakage, may proceed anyway!"));
		return;
	}

	if (fixbydeconf && !f_autodeconf) {
		ohshit(_("installing %s would break %s, and\n"
		         " deconfiguration is not permitted (--auto-deconfigure might help)"),
		       pkgbin_name(pkg, &pkg->available, pnaw_nonambig),
		       pkg_name(fixbydeconf, pnaw_nonambig));
	} else {
		ohshit(_("installing %s would break existing software"),
		       pkgbin_name(pkg, &pkg->available, pnaw_nonambig));
	}
}

/* TODO: Refactor to reduce nesting levels. */
void
check_conflict(struct dependency *dep, struct pkginfo *pkg,
               const char *pfilename)
{
	struct pkginfo *fixbyrm;
	struct deppossi *pdep, flagdeppossi = { 0 };
	struct varbuf conflictwhy = VARBUF_INIT;
	struct varbuf removalwhy = VARBUF_INIT;
	struct dependency *providecheck;

	fixbyrm = NULL;

	if (depisok(dep, &conflictwhy, &fixbyrm, NULL, false)) {
		varbuf_destroy(&conflictwhy);
		varbuf_destroy(&removalwhy);
		return;
	}

	if (fixbyrm) {
		ensure_package_clientdata(fixbyrm);
		if (fixbyrm->clientdata->istobe == PKG_ISTOBE_INSTALLNEW) {
			fixbyrm = dep->up;
			ensure_package_clientdata(fixbyrm);
		}

		/* TODO: Refactor this overly complex conditional. */
		if (((pkg->available.essential ||
		      pkg->available.is_protected) &&
		     (fixbyrm->installed.essential ||
		      fixbyrm->installed.is_protected)) ||
		    (((fixbyrm->want != PKG_WANT_INSTALL &&
		       fixbyrm->want != PKG_WANT_HOLD) ||
		      does_replace(pkg, &pkg->available, fixbyrm, &fixbyrm->installed)) &&
		     ((!fixbyrm->installed.essential ||
		       in_force(FORCE_REMOVE_ESSENTIAL)) ||
		      (!fixbyrm->installed.is_protected ||
		       in_force(FORCE_REMOVE_PROTECTED))))) {
			if (fixbyrm->clientdata->istobe != PKG_ISTOBE_NORMAL &&
			    fixbyrm->clientdata->istobe != PKG_ISTOBE_DECONFIGURE)
				internerr("package %s to be fixed by removal is not to be normal "
				          "nor deconfigure, is to be %d",
				          pkg_name(pkg, pnaw_always),
				          fixbyrm->clientdata->istobe);
			fixbyrm->clientdata->istobe = PKG_ISTOBE_REMOVE;
			notice(_("considering removing %s in favour of %s ..."),
			       pkg_name(fixbyrm, pnaw_nonambig),
			       pkgbin_name(pkg, &pkg->available, pnaw_nonambig));

			if (!(fixbyrm->status == PKG_STAT_INSTALLED ||
			      fixbyrm->status == PKG_STAT_TRIGGERSPENDING ||
			      fixbyrm->status == PKG_STAT_TRIGGERSAWAITED)) {
				notice(_("%s is not properly installed; ignoring any dependencies on it"),
				             pkg_name(fixbyrm, pnaw_nonambig));
				pdep = NULL;
			} else {
				for (pdep = fixbyrm->set->depended.installed;
				     pdep;
				     pdep = pdep->rev_next) {
					if (pdep->up->type != dep_depends &&
					    pdep->up->type != dep_predepends)
						continue;

					if (depisok(pdep->up, &removalwhy, NULL, NULL, false))
						continue;

					if (!try_remove_can(pdep, fixbyrm, varbuf_str(&removalwhy)))
						break;
				}
				if (!pdep) {
					/* If we haven't found a reason not to
					 * yet, let's look some more. */
					for (providecheck = fixbyrm->installed.depends;
					     providecheck;
					     providecheck = providecheck->next) {
						if (providecheck->type != dep_provides)
							continue;

						for (pdep = providecheck->list->ed->depended.installed;
						     pdep;
						     pdep = pdep->rev_next) {
							if (pdep->up->type != dep_depends &&
							    pdep->up->type != dep_predepends)
								continue;

							if (depisok(pdep->up, &removalwhy, NULL, NULL, false))
								continue;

							notice(_("may have trouble removing %s, as it provides %s ..."),
							       pkg_name(fixbyrm, pnaw_nonambig),
							       providecheck->list->ed->name);
							if (!try_remove_can(pdep, fixbyrm, varbuf_str(&removalwhy)))
								goto break_from_both_loops_at_once;
						}
					}
					break_from_both_loops_at_once:;
				}
			}
			if (!pdep && skip_due_to_hold(fixbyrm)) {
				pdep = &flagdeppossi;
			}
			if (!pdep && (fixbyrm->eflag & PKG_EFLAG_REINSTREQ)) {
				if (in_force(FORCE_REMOVE_REINSTREQ)) {
					notice(_("package %s requires reinstallation, but will "
					         "remove anyway as you requested"),
					       pkg_name(fixbyrm, pnaw_nonambig));
				} else {
					notice(_("package %s requires reinstallation, will not remove"),
					       pkg_name(fixbyrm, pnaw_nonambig));
					pdep = &flagdeppossi;
				}
			}
			if (!pdep) {
				/* This conflict is OK - we'll remove the
				 * conflictor. */
				enqueue_conflictor(fixbyrm);
				varbuf_destroy(&conflictwhy); varbuf_destroy(&removalwhy);
				notice(_("yes, will remove %s in favour of %s"),
				       pkg_name(fixbyrm, pnaw_nonambig),
				       pkgbin_name(pkg, &pkg->available, pnaw_nonambig));

				return;
			}
			/* Put it back. */
			fixbyrm->clientdata->istobe = PKG_ISTOBE_NORMAL;
		}
	}
	notice(_("regarding %s containing %s:\n%s"), pfilename,
	       pkgbin_name(pkg, &pkg->available, pnaw_nonambig),
	       varbuf_str(&conflictwhy));
	if (!force_conflicts(dep->list))
		ohshit(_("conflicting packages - not installing %s"),
		       pkgbin_name(pkg, &pkg->available, pnaw_nonambig));
	warning(_("ignoring conflict, may proceed anyway!"));
	varbuf_destroy(&conflictwhy);

	return;
}

void
cu_cidir(int argc, void **argv)
{
	char *cidir = (char*)argv[0];
	char *cidirrest = (char*)argv[1];

	cidirrest[-1] = '\0';
	path_remove_tree(cidir);
	free(cidir);
}

void
cu_fileslist(int argc, void **argv)
{
	tar_pool_release();
}

/* TODO: Refactor to reduce nesting levels. */
int
archivefiles(const char *const *argv)
{
	const char *const *volatile argp;
	char **volatile arglist = NULL;
	int i;
	jmp_buf ejbuf;
	enum modstatdb_rw msdbflags;

	trigproc_install_hooks();

	if (!f_act)
		msdbflags = msdbrw_readonly;
	else if (cipaction->arg_int == act_avail)
		msdbflags = msdbrw_readonly | msdbrw_available_write;
	else if (in_force(FORCE_NON_ROOT))
		msdbflags = msdbrw_write;
	else
		msdbflags = msdbrw_needsuperuser;

	modstatdb_open(msdbflags);

	checkpath();
	pkg_infodb_upgrade();

	log_message("startup archives %s", cipaction->olong);

	if (f_recursive) {
		const char *const *ap;
		int nfiles = 0;

		if (!*argv)
			badusage(_("--%s --recursive needs at least one path argument"),
			         cipaction->olong);

		for (ap = argv; *ap; ap++) {
			struct treeroot *tree;
			struct treenode *node;

			tree = treewalk_open((const char *)*ap,
			                     TREEWALK_FOLLOW_LINKS, NULL);

			while ((node = treewalk_next(tree))) {
				const char *nodename;

				if (!S_ISREG(treenode_get_mode(node)))
					continue;

				/* Check if it looks like a .deb file. */
				nodename = treenode_get_pathname(node);
				if (strcmp(nodename + strlen(nodename) - 4, DEBEXT) != 0)
					continue;

				arglist = m_realloc(arglist, sizeof(char *) * (nfiles + 2));
				arglist[nfiles++] = m_strdup(nodename);
			}

			treewalk_close(tree);
		}

		if (!nfiles)
			ohshit(_("searched, but found no packages (files matching *.deb)"));

		arglist[nfiles] = NULL;
		argp = (const char **volatile)arglist;
	} else {
		if (!*argv)
			badusage(_("--%s needs at least one package archive file argument"),
			         cipaction->olong);
		argp = argv;
	}

	/* Perform some sanity checks on the passed archives. */
	for (i = 0; argp[i]; i++) {
		struct stat st;

		/* We need the filename to exist. */
		if (stat(argp[i], &st) < 0)
			ohshite(_("cannot access archive '%s'"), argp[i]);

		/* We cannot work with anything that is not a regular file. */
		if (!S_ISREG(st.st_mode))
			ohshit(_("archive '%s' is not a regular file"),
			       argp[i]);
	}

	currenttime = time(NULL);

	/* Initialize fname variables contents. */

	varbuf_set_str(&fnamevb, dpkg_fsys_get_dir());
	varbuf_set_str(&fnametmpvb, dpkg_fsys_get_dir());
	varbuf_set_str(&fnamenewvb, dpkg_fsys_get_dir());

	varbuf_snapshot(&fnamevb, &fname_state);
	varbuf_snapshot(&fnametmpvb, &fnametmp_state);
	varbuf_snapshot(&fnamenewvb, &fnamenew_state);

	ensure_diversions();
	ensure_statoverrides(STATDB_PARSE_NORMAL);

	for (i = 0; argp[i]; i++) {
		if (setjmp(ejbuf)) {
			pop_error_context(ehflag_bombout);
			if (abort_processing)
				break;
			continue;
		}
		push_error_context_jump(&ejbuf, print_error_perarchive, argp[i]);

		dpkg_selabel_load();

		process_archive(argp[i]);
		onerr_abort++;
		m_output(stdout, _("<standard output>"));
		m_output(stderr, _("<standard error>"));
		onerr_abort--;

		pop_error_context(ehflag_normaltidy);
	}

	dpkg_selabel_close();

	if (arglist) {
		for (i = 0; arglist[i]; i++)
			free(arglist[i]);
		free(arglist);
	}

	switch (cipaction->arg_int) {
	case act_install:
	case act_configure:
	case act_triggers:
	case act_remove:
	case act_purge:
		process_queue();
	case act_unpack:
	case act_avail:
		break;
	default:
		internerr("unknown action '%d'", cipaction->arg_int);
	}

	trigproc_run_deferred();
	modstatdb_shutdown();

	return 0;
}

/**
 * Decide whether we want to install a new version of the package.
 *
 * @param pkg The package with the version we might want to install
 *
 * @retval true  If the package should be skipped.
 * @retval false If the package should be installed.
 */
bool
wanttoinstall(struct pkginfo *pkg)
{
	int rc;

	if (pkg->want != PKG_WANT_INSTALL && pkg->want != PKG_WANT_HOLD) {
		if (f_alsoselect) {
			printf(_("Selecting previously unselected package %s.\n"),
			       pkgbin_name(pkg, &pkg->available, pnaw_nonambig));
			return true;
		} else {
			printf(_("Skipping unselected package %s.\n"),
			       pkgbin_name(pkg, &pkg->available, pnaw_nonambig));
			return false;
		}
	}

	if (pkg->eflag & PKG_EFLAG_REINSTREQ)
		return true;
	if (pkg->status < PKG_STAT_UNPACKED)
		return true;

	rc = dpkg_version_compare(&pkg->available.version,
	                          &pkg->installed.version);
	if (rc > 0) {
		return true;
	} else if (rc == 0) {
		/* Same version fully installed. */
		if (f_skipsame && pkg->available.arch == pkg->installed.arch) {
			notice(_("package %s (%s) with same version already installed, skipping"),
			       pkg_name(pkg, pnaw_nonambig),
			       versiondescribe(&pkg->installed.version, vdew_nonambig));
			return false;
		} else {
			return true;
		}
	} else if (in_force(FORCE_DOWNGRADE)) {
		warning(_("downgrading %s (%s) to (%s)"),
		        pkg_name(pkg, pnaw_nonambig),
		        versiondescribe(&pkg->installed.version, vdew_nonambig),
		        versiondescribe(&pkg->available.version, vdew_nonambig));
		return true;
	} else {
		notice(_("will not downgrade %s (%s) to (%s), skipping"),
		       pkg_name(pkg, pnaw_nonambig),
		       versiondescribe(&pkg->installed.version, vdew_nonambig),
		       versiondescribe(&pkg->available.version, vdew_nonambig));
		return false;
	}
}
