/*
 * dpkg - main program for package management
 * main.c - main program
 *
 * Copyright © 1994,1995 Ian Jackson <ijackson@chiark.greenend.org.uk>
 * Copyright © 2006-2016 Guillem Jover <guillem@debian.org>
 * Copyright © 2010 Canonical Ltd.
 *   written by Martin Pitt <martin.pitt@canonical.com>
 *
 * 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/wait.h>

#include <errno.h>
#include <limits.h>
#ifdef HAVE_LOCALE_H
#include <locale.h>
#endif
#include <string.h>
#include <fcntl.h>
#include <dirent.h>
#include <unistd.h>
#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>

#include <dpkg/macros.h>
#include <dpkg/i18n.h>
#include <dpkg/c-ctype.h>
#include <dpkg/dpkg.h>
#include <dpkg/dpkg-db.h>
#include <dpkg/arch.h>
#include <dpkg/subproc.h>
#include <dpkg/command.h>
#include <dpkg/pager.h>
#include <dpkg/options.h>
#include <dpkg/db-fsys.h>

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

static int
printversion(const char *const *argv)
{
	if (f_robot) {
		printf("%s", PACKAGE_VERSION);
	} else {
		printf(_("Debian '%s' package management program version %s.\n"),
		       DPKG, PACKAGE_RELEASE);
		printf(_(
"This is free software; see the GNU General Public License version 2 or\n"
"later for copying conditions. There is NO warranty.\n"));
	}

	m_output(stdout, _("<standard output>"));

	return 0;
}

/*
 * FIXME: Options that need fixing:
 * dpkg --command-fd
 */

static int
usage(const char *const *argv)
{
	char *def_force;

	printf(_(
"Usage: %s [<option>...] <command>\n"
	), DPKG);
	print_option_sep();

	printf(_(
"Commands:\n"
	));
	print_option(_(
"  -i, --install <archive-spec>\n"
"          Install the archives.\n"
	));
	print_option(_(
"      --unpack <archive-spec>\n"
"          Unpack the archives.\n"
	));
	print_option(_(
"      --configure <package-spec>\n"
"          Configure the packages.\n"
	));
	print_option(_(
"      --triggers-only <package-spec>\n"
"          Process triggers for the packages.\n"
	));
	print_option(_(
"  -r, --remove <package-spec>\n"
"          Remove the packages.\n"
	));
	print_option(_(
"  -P, --purge <package-spec>\n"
"          Purge the packages.\n"
	));
	print_option(_(
"  -V, --verify [<package>...]\n"
"          Verify the integrity of packages.\n"
	));
	print_option(_(
"  -C, --audit [<package>...]\n"
"          Check for broken packages.\n"
	));
	print_option(_(
"  -s, --status [<package>...]\n"
"          Show package status details.\n"
	));
	print_option(_(
"  -l, --list [<pattern>...]\n"
"          List packages concisely.\n"
	));
	print_option(_(
"  -L, --listfiles <package>...\n"
"          List files 'owned' by packages.\n"
	));
	print_option(_(
"  -S, --search <pattern>...\n"
"          Find packages owning files.\n"
	));
	print_option(_(
"      --get-selections [<pattern>...]\n"
"          Get list of selections to stdout.\n"
	));
	print_option(_(
"      --set-selections\n"
"          Set package selections from stdin.\n"
	));
	print_option(_(
"      --clear-selections\n"
"          Deselect every non-essential package.\n"
	));
	print_option(_(
"  -p, --print-avail [<package>...]\n"
"          Show available package version details.\n"
	));
	print_option(_(
"  -A, --record-avail <archive-spec>\n"
"          Record the archives in the available file.\n"
	));
	print_option(_(
"      --update-avail [<Packages-file>]\n"
"          Replace available packages information.\n"
	));
	print_option(_(
"      --merge-avail [<Packages-file>]\n"
"          Merge available package information.\n"
	));
	print_option(_(
"      --clear-avail\n"
"          Erase existing available package information.\n"
	));
	print_option(_(
"      --add-architecture <arch>\n"
"          Add <arch> to the list of architectures.\n"
	));
	print_option(_(
"      --remove-architecture <arch>\n"
"          Remove <arch> from the list of architectures.\n"
	));
	print_option(_(
"      --print-architecture\n"
"          Print native dpkg architecture.\n"
	));
	print_option(_(
"      --print-foreign-architectures\n"
"          Print allowed foreign architectures.\n"
	));
	print_option(_(
"      --validate-<thing> <string>\n"
"          Validate a <thing>'s <string>.\n"
	));
	print_option(_(
"      --compare-versions <a> <op> <b>\n"
"          Compare version numbers (see below).\n"
	));
	print_option(_(
"      --predep-package\n"
"          Print pre-dependencies to unpack.\n"
	));
	print_option(_(
"      --assert-help\n"
"          Show help on assertions.\n"
	));
	print_option(_(
"      --assert-<feature>\n"
"          Assert support for the specified feature.\n"
	));
	print_option(_(
"      --force-help\n"
"          Show help on forcing.\n"
	));
	print_option(_(
"  -Dh, --debug=help\n"
"          Show help on debugging.\n"
	));
	print_option(_(
"  -?, --help\n"
"          Show this help message.\n"
	));
	print_option(_(
"      --version\n"
"          Show the version.\n"
	));
	print_option_sep();

	printf(_(
"<archive-spec> is: <.deb file name>... | (-R|--recursive) <directory>...\n"
"<package-spec> is: <package>... | (-a|--pending)\n"
	));
	print_option_sep();

	printf(_(
"Validatable things: pkgname, archname, trigname, version.\n"
	));
	print_option_sep();

	printf(_(
"Use dpkg with -b, --build, -c, --contents, -e, --control, -I, --info,\n"
"  -f, --field, -x, --extract, -X, --vextract, --ctrl-tarfile, --fsys-tarfile\n"
"on archives (type %s --help).\n"
	), BACKEND);
	print_option_sep();

	printf(_(
"Options:\n"
	));
	print_option(_(
"  -O, --selected-only\n"
"          Skip packages not selected for install/upgrade.\n"
	));
	print_option(_(
"  -E, --skip-same-version\n"
"          Skip packages with same installed version/arch.\n"
	));
	print_option(_(
"  -G, --refuse-downgrade\n"
"          Skip packages with earlier version than installed.\n"
	));
	print_option(_(
"  -B, --auto-deconfigure\n"
"          Install even if it would break some other package.\n"
	));
	print_option(_(
"      --triggers\n"
"          Force consequential trigger processing.\n"
	));
	print_option(_(
"      --no-triggers\n"
"          Skip consequential trigger processing.\n"
	));
	print_option(_(
"      --verify-format=<format>\n"
"          Verify output format (supported: 'rpm').\n"
	));
	print_option(_(
"      --robot\n"
"          Use machine-readable output on some commands.\n"
	));
	print_option(_(
"      --no-pager\n"
"          Disables the use of any pager.\n"
	));
	print_option(_(
"      --no-debsig\n"
"          Do not try to verify package signatures.\n"
	));
	print_option(_(
"      --ignore-depends=<package>[,...]\n"
"          Ignore dependencies involving <package>.\n"
	));
	print_option(_(
"      --force-<thing>[,...]\n"
"          Override problems (see --force-help).\n"
	));
	def_force = get_force_string();
	print_option_def("%s", def_force);
	free(def_force);
	print_option_env("DPKG_FORCE");
	print_option(_(
"      --no-force-<thing>[,...]\n"
"          Stop when problems encountered.\n"
	));
	print_option(_(
"      --refuse-<thing>[,...]\n"
"          Alias for --no-force.\n"
	));
	print_option(_(
"      --abort-after <n>\n"
"          Abort after encountering <n> errors.\n"
	));
	print_option(_(
"      --no-act\n"
"          Print what would be done, but perform no action.\n"
	));
	print_option(_(
"      --dry-run\n"
"          Alias for --no-act.\n"
	));
	print_option(_(
"      --simulate\n"
"          Alias for --no-act.\n"
	));
	print_option(_(
"  -D, --debug=<octal>\n"
"          Enable debugging output (see -Dhelp or --debug=help).\n"
	));
	print_option(_(
"      --path-exclude=<pattern>\n"
"          Do not install paths which match a shell pattern.\n"
	));
	print_option(_(
"      --path-include=<pattern>\n"
"          Re-include a pattern after a previous exclusion.\n"
	));
	print_option(_(
"      --pre-invoke=<command>\n"
"          Set a pre-invoke hook.\n"
	));
	print_option(_(
"      --post-invoke=<command>\n"
"          Set a post-invoke hook.\n"
	));
	print_option(_(
"      --status-fd <n>\n"
"          Send status change updates to file descriptor <n>.\n"
	));
	print_option(_(
"      --status-logger=<command>\n"
"          Send status change updates to <command>'s stdin.\n"
	));
	print_option(_(
"      --log=<filename>\n"
"          Log status changes and actions to <filename>.\n"
	));
	print_option(_(
"      --admindir=<directory>\n"
"          Change the database directory.\n"
	));
	print_option_def(ADMINDIR);
	print_option_env("DPKG_ADMINDIR");
	print_option(_(
"      --instdir=<directory>\n"
"          Change the installation directory.\n"
	));
	print_option_def("/");
	print_option(_(
"      --root=<directory>\n"
"          Change the root directory.\n"
	));
	print_option_def("/");
	print_option_env("DPKG_ROOT");
	print_option_sep();

	printf(_(
"Comparison operators for --compare-versions are:\n"
"  lt le eq ne ge gt       (treat empty version as earlier than any version);\n"
"  lt-nl le-nl ge-nl gt-nl (treat empty version as later than any version);\n"
"  < << <= = >= >> >       (only for compatibility with control file syntax).\n"
	));
	print_option_sep();

	printf(_(
"Use 'apt' or 'aptitude' for user-friendly package management.\n"));

	m_output(stdout, _("<standard output>"));

	return 0;
}

static const char printforhelp[] = N_(
"Type dpkg --help for help about installing and deinstalling packages [*];\n"
"Use 'apt' or 'aptitude' for user-friendly package management;\n"
"Type dpkg -Dhelp for a list of dpkg debug flag values;\n"
"Type dpkg --force-help for a list of forcing options;\n"
"Type dpkg-deb --help for help about manipulating *.deb files;\n"
"\n"
"Options marked [*] produce a lot of output - pipe it through 'less' or 'more' !");

int f_act = 1;
int f_alsoselect = 1;
int f_autodeconf = 0;
int f_debsig = 1;
int f_pending = 0;
int f_recursive = 0;
int f_robot = 0;
int f_skipsame = 0;
int f_triggers = 0;

int errabort = 50;
struct pkg_list *ignoredependss = NULL;

#define DBG_DEF(n, d) \
	{ .flag = dbg_##n, .name = #n, .desc = d }

static const struct debuginfo {
	int flag;
	const char *name;
	const char *desc;
} debuginfos[] = {
	DBG_DEF(general,         N_("Generally helpful progress information")),
	DBG_DEF(scripts,         N_("Invocation and status of maintainer scripts")),
	DBG_DEF(eachfile,        N_("Output for each file processed")),
	DBG_DEF(eachfiledetail,  N_("Lots of output for each file processed")),
	DBG_DEF(conff,           N_("Output for each configuration file")),
	DBG_DEF(conffdetail,     N_("Lots of output for each configuration file")),
	DBG_DEF(depcon,          N_("Dependencies and conflicts")),
	DBG_DEF(depcondetail,    N_("Lots of dependencies/conflicts output")),
	DBG_DEF(triggers,        N_("Trigger activation and processing")),
	DBG_DEF(triggersdetail,  N_("Lots of output regarding triggers")),
	DBG_DEF(triggersstupid,  N_("Silly amounts of output regarding triggers")),
	DBG_DEF(veryverbose,     N_("Lots of drivel about eg the dpkg/info directory")),
	DBG_DEF(stupidlyverbose, N_("Insane amounts of drivel")),
	{ 0, NULL, NULL }
};

static void
set_debug(const struct cmdinfo *cpi, const char *value)
{
	long mask;

	if (*value == 'h') {
		const struct debuginfo *dip;

		printf(_(
"%s debugging option, --debug=<octal> or -D<octal>:\n"
"\n"
" Number  Ref. in source   Description\n"), DPKG);

		for (dip = debuginfos; dip->name; dip++)
			printf(" %6o  %-16s %s\n",
			       dip->flag, dip->name, gettext(dip->desc));

		printf(_("\n"
"Debugging options can be mixed using bitwise-or.\n"
"Note that the meanings and values are subject to change.\n"));

		m_output(stdout, _("<standard output>"));

		exit(0);
	}

	mask = debug_parse_mask(value);
	if (mask < 0)
		badusage(_("--%s requires a positive octal argument"),
		         cpi->olong);
}

static void
set_no_pager(const struct cmdinfo *ci, const char *value)
{
	pager_enable(false);

	/* Let's communicate this to our backends. */
	setenv("DPKG_PAGER", "cat", 1);
}

static void
set_filter(const struct cmdinfo *cip, const char *value)
{
	filter_add(value, cip->arg_int);
}

static void
set_verify_format(const struct cmdinfo *cip, const char *value)
{
	if (!verify_set_output(value))
		badusage(_("unknown verify output format '%s'"), value);
}

static void
set_ignore_depends(const struct cmdinfo *cip, const char *value)
{
	char *copy, *p;

	copy = m_malloc(strlen(value) + 2);
	strcpy(copy, value);
	copy[strlen(value) + 1] = '\0';

	for (p = copy; *p; p++) {
		if (*p != ',')
			continue;

		*p++ = '\0';
		if (!*p || *p == ',' || p == copy + 1)
			badusage(_("null package name in --%s comma-separated list '%s'"),
			         cip->olong, value);
	}

	p = copy;
	while (*p) {
		struct pkginfo *pkg;

		pkg = dpkg_options_parse_pkgname(cip, p);
		pkg_list_prepend(&ignoredependss, pkg);

		p += strlen(p) + 1;
	}

	free(copy);
}

static void
set_integer(const struct cmdinfo *cip, const char *value)
{
	*cip->iassignto = dpkg_options_parse_arg_int(cip, value);
}

static void
set_pipe(const struct cmdinfo *cip, const char *value)
{
	long v;

	v = dpkg_options_parse_arg_int(cip, value);

	statusfd_add(v);
}

static void
set_log(const struct cmdinfo *cip, const char *value)
{
	log_set_file(value);
}

static bool
is_invoke_action(enum action action)
{
	switch (action) {
	case act_unpack:
	case act_configure:
	case act_install:
	case act_triggers:
	case act_remove:
	case act_purge:
	case act_arch_add:
	case act_arch_remove:
		return true;
	default:
		return false;
	}
}

static bool
can_invoke_hooks(enum action action)
{
	if (!is_invoke_action(action))
		return false;

	if (!f_act)
		return false;

	if (in_force(FORCE_NON_ROOT))
		return true;

	if (getuid() || geteuid())
		return false;

	return true;
}

static struct invoke_list pre_invoke_hooks = {
	.head = NULL,
	.tail = &pre_invoke_hooks.head,
};
static struct invoke_list post_invoke_hooks = {
	.head = NULL,
	.tail = &post_invoke_hooks.head,
};
static struct invoke_list status_loggers = {
	.head = NULL,
	.tail = &status_loggers.head,
};

static void
set_invoke_hook(const struct cmdinfo *cip, const char *value)
{
	struct invoke_list *hook_list = cip->arg_ptr;
	struct invoke_hook *hook_new;

	hook_new = m_malloc(sizeof(*hook_new));
	hook_new->command = m_strdup(value);
	hook_new->next = NULL;

	/* Add the new hook at the tail of the list to preserve the order. */
	*hook_list->tail = hook_new;
	hook_list->tail = &hook_new->next;
}

static void
run_invoke_hooks(const char *action, struct invoke_list *hook_list)
{
	struct invoke_hook *hook;

	setenv("DPKG_HOOK_ACTION", action, 1);

	for (hook = hook_list->head; hook; hook = hook->next) {
		int status;

		/* XXX: As an optimization, use exec instead if no shell metachar are
		 * used “!$=&|\\`'"^~;<>{}[]()?*#”. */
		status = system(hook->command);
		if (status != 0)
			ohshit(_("cannot execute hook '%s', exit code %d"),
			       hook->command, status);
	}

	unsetenv("DPKG_HOOK_ACTION");
}

static void
free_invoke_hooks(struct invoke_list *hook_list)
{
	struct invoke_hook *hook, *hook_next;

	for (hook = hook_list->head; hook; hook = hook_next) {
		hook_next = hook->next;
		free(hook->command);
		free(hook);
	}
}

static int
run_logger(struct invoke_hook *hook, const char *name)
{
	pid_t pid;
	int p[2];

	m_pipe(p);

	pid = subproc_fork();
	if (pid == 0) {
		/* Setup stdin and stdout. */
		m_dup2(p[0], 0);
		close(1);

		close(p[0]);
		close(p[1]);

		command_shell(hook->command, name);
	}
	close(p[0]);

	return p[1];
}

static void
run_status_loggers(struct invoke_list *hook_list)
{
	struct invoke_hook *hook;

	for (hook = hook_list->head; hook; hook = hook->next) {
		int fd;

		fd = run_logger(hook, _("status logger"));
		statusfd_add(fd);
	}
}

static int
arch_add(const char *const *argv)
{
	struct dpkg_arch *arch;
	const char *archname = *argv++;

	if (archname == NULL || *argv)
		badusage(_("--%s takes exactly one argument"), cipaction->olong);

	dpkg_arch_load_list();

	arch = dpkg_arch_add(archname);
	switch (arch->type) {
	case DPKG_ARCH_NATIVE:
	case DPKG_ARCH_FOREIGN:
		break;
	case DPKG_ARCH_INVALID:
		ohshit(_("architecture '%s' is invalid: %s"), archname,
		       dpkg_arch_name_is_invalid(archname));
	default:
		ohshit(_("architecture '%s' is reserved and cannot be added"),
		       archname);
	}

	dpkg_arch_save_list();

	return 0;
}

static int
arch_remove(const char *const *argv)
{
	const char *archname = *argv++;
	struct dpkg_arch *arch;
	struct pkg_hash_iter *iter;
	struct pkginfo *pkg;

	if (archname == NULL || *argv)
		badusage(_("--%s takes exactly one argument"),
		         cipaction->olong);

	modstatdb_open(msdbrw_readonly);

	arch = dpkg_arch_find(archname);
	if (arch->type != DPKG_ARCH_FOREIGN) {
		warning(_("cannot remove non-foreign architecture '%s'"),
		        arch->name);
		return 0;
	}

	/* Check if it's safe to remove the architecture from the db. */
	iter = pkg_hash_iter_new();
	while ((pkg = pkg_hash_iter_next_pkg(iter))) {
		if (pkg->status < PKG_STAT_HALFINSTALLED)
			continue;

		if (pkg->installed.arch == arch) {
			if (in_force(FORCE_ARCHITECTURE))
				warning(_("removing architecture '%s' currently in use by database"),
				        arch->name);
			else
				ohshit(_("cannot remove architecture '%s' currently in use by the database"),
				       arch->name);
			break;
		}
	}
	pkg_hash_iter_free(iter);

	dpkg_arch_unmark(arch);
	dpkg_arch_save_list();

	modstatdb_shutdown();

	return 0;
}

int
execbackend(const char *const *argv) DPKG_ATTR_NORET;
int
commandfd(const char *const *argv);

/* This table has both the action entries in it and the normal options.
 * The action entries are made with the ACTION macro, as they all
 * have a very similar structure. */
static const struct cmdinfo cmdinfos[] = {
#define ACTIONBACKEND(longopt, shortopt, backend) \
	{ longopt, shortopt, 0, NULL, NULL, setaction, 0, (void *)backend, execbackend }

	ACTION( "install",                        'i', act_install,              archivefiles    ),
	ACTION( "unpack",                          0,  act_unpack,               archivefiles    ),
	ACTION( "record-avail",                   'A', act_avail,                archivefiles    ),
	ACTION( "configure",                       0,  act_configure,            packages        ),
	ACTION( "remove",                         'r', act_remove,               packages        ),
	ACTION( "purge",                          'P', act_purge,                packages        ),
	ACTION( "triggers-only",                   0,  act_triggers,             packages        ),
	ACTION( "verify",                         'V', act_verify,               verify          ),
	ACTIONBACKEND( "listfiles",               'L', DPKGQUERY),
	ACTIONBACKEND( "status",                  's', DPKGQUERY),
	ACTION( "get-selections",                  0,  act_getselections,        getselections   ),
	ACTION( "set-selections",                  0,  act_setselections,        setselections   ),
	ACTION( "clear-selections",                0,  act_clearselections,      clearselections ),
	ACTIONBACKEND( "print-avail",             'p', DPKGQUERY),
	ACTION( "update-avail",                    0,  act_avreplace,            updateavailable ),
	ACTION( "merge-avail",                     0,  act_avmerge,              updateavailable ),
	ACTION( "clear-avail",                     0,  act_avclear,              updateavailable ),
	ACTION( "forget-old-unavail",              0,  act_forgetold,            forgetold       ),
	ACTION( "audit",                          'C', act_audit,                audit           ),
	ACTION( "yet-to-unpack",                   0,  act_unpackchk,            unpackchk       ),
	ACTIONBACKEND( "list",                    'l', DPKGQUERY),
	ACTIONBACKEND( "search",                  'S', DPKGQUERY),
	ACTION_MUX( "assert",                      0,  act_assert_feature,       assert_feature, &assert_feature_name),
	ACTION( "add-architecture",                0,  act_arch_add,             arch_add        ),
	ACTION( "remove-architecture",             0,  act_arch_remove,          arch_remove     ),
	ACTION( "print-architecture",              0,  act_printarch,            printarch   ),
	ACTION( "print-foreign-architectures",     0,  act_printforeignarches,   print_foreign_arches ),
	ACTION( "predep-package",                  0,  act_predeppackage,        predeppackage   ),
	ACTION( "validate-pkgname",                0,  act_validate_pkgname,     validate_pkgname ),
	ACTION( "validate-trigname",               0,  act_validate_trigname,    validate_trigname ),
	ACTION( "validate-archname",               0,  act_validate_archname,    validate_archname ),
	ACTION( "validate-version",                0,  act_validate_version,     validate_version ),
	ACTION( "compare-versions",                0,  act_cmpversions,          cmpversions     ),
/*
	ACTION( "command-fd",                   'c', act_commandfd,   commandfd     ),
*/
	ACTION( "help",                           '?', act_help,                 usage),
	ACTION( "version",                         0,  act_version,              printversion),

	{ "pre-invoke",        0,   1, NULL,          NULL,      set_invoke_hook, 0, &pre_invoke_hooks },
	{ "post-invoke",       0,   1, NULL,          NULL,      set_invoke_hook, 0, &post_invoke_hooks },
	{ "path-exclude",      0,   1, NULL,          NULL,      set_filter,     0 },
	{ "path-include",      0,   1, NULL,          NULL,      set_filter,     1 },
	{ "verify-format",     0,   1, NULL,          NULL,      set_verify_format },
	{ "status-logger",     0,   1, NULL,          NULL,      set_invoke_hook, 0, &status_loggers },
	{ "status-fd",         0,   1, NULL,          NULL,      set_pipe, 0 },
	{ "log",               0,   1, NULL,          NULL,      set_log,  0 },
	{ "pending",           'a', 0, &f_pending,    NULL,      NULL,    1 },
	{ "recursive",         'R', 0, &f_recursive,  NULL,      NULL,    1 },
	{ "no-act",            0,   0, &f_act,        NULL,      NULL,    0 },
	{ "dry-run",           0,   0, &f_act,        NULL,      NULL,    0 },
	{ "simulate",          0,   0, &f_act,        NULL,      NULL,    0 },
	{ "no-pager",          0,   0, NULL,          NULL,      set_no_pager,  0 },
	{ "no-debsig",         0,   0, &f_debsig,     NULL,      NULL,    0 },
	/* Alias ('G') for --refuse. */
	{  NULL,               'G', 0, NULL,          NULL,      reset_force_option, FORCE_DOWNGRADE },
	{ "selected-only",     'O', 0, &f_alsoselect, NULL,      NULL,    0 },
	{ "triggers",           0,  0, &f_triggers,   NULL,      NULL,    1 },
	{ "no-triggers",        0,  0, &f_triggers,   NULL,      NULL,   -1 },
	/* TODO: Remove ('N') sometime. */
	{ "no-also-select",    'N', 0, &f_alsoselect, NULL,      NULL,    0 },
	{ "skip-same-version", 'E', 0, &f_skipsame,   NULL,      NULL,    1 },
	{ "auto-deconfigure",  'B', 0, &f_autodeconf, NULL,      NULL,    1 },
	{ "robot",             0,   0, &f_robot,      NULL,      NULL,    1 },
	{ "root",              0,   1, NULL,          NULL,      set_root,      0 },
	{ "abort-after",       0,   1, &errabort,     NULL,      set_integer,   0 },
	{ "admindir",          0,   1, NULL,          NULL,      set_admindir,  0 },
	{ "instdir",           0,   1, NULL,          NULL,      set_instdir,   0 },
	{ "ignore-depends",    0,   1, NULL,          NULL,      set_ignore_depends, 0 },
	{ "force",             0,   2, NULL,          NULL,      set_force_option,   1 },
	{ "refuse",            0,   2, NULL,          NULL,      set_force_option,   0 },
	{ "no-force",          0,   2, NULL,          NULL,      set_force_option,   0 },
	{ "debug",             'D', 1, NULL,          NULL,      set_debug,     0 },
	ACTIONBACKEND( "build",		'b', BACKEND),
	ACTIONBACKEND( "contents",		'c', BACKEND),
	ACTIONBACKEND( "control",		'e', BACKEND),
	ACTIONBACKEND( "info",		'I', BACKEND),
	ACTIONBACKEND( "field",		'f', BACKEND),
	ACTIONBACKEND( "extract",		'x', BACKEND),
	ACTIONBACKEND( "vextract",		'X', BACKEND),
	ACTIONBACKEND( "ctrl-tarfile",	0,   BACKEND),
	ACTIONBACKEND( "fsys-tarfile",	0,   BACKEND),
	{ NULL,                0,   0, NULL,          NULL,      NULL,          0 }
};

int
execbackend(const char *const *argv)
{
	struct command cmd;

	command_init(&cmd, cipaction->arg_ptr, NULL);
	command_add_arg(&cmd, cipaction->arg_ptr);
	command_add_arg(&cmd, str_fmt("--%s", cipaction->olong));

	/* Explicitly separate arguments from options as any user-supplied
	 * separator got stripped by the option parser */
	command_add_arg(&cmd, "--");
	command_add_argl(&cmd, (const char **)argv);

	command_exec(&cmd);
}

int
commandfd(const char *const *argv)
{
	struct varbuf linevb = VARBUF_INIT;
	const char * pipein;
	const char **newargs = NULL, **endargs;
	char *ptr, *endptr;
	FILE *in;
	int infd;
	int ret = 0;
	int c, lno, i;
	bool skipchar;

	pipein = *argv++;
	if (pipein == NULL || *argv)
		badusage(_("--%s takes exactly one argument"),
		         cipaction->olong);

	infd = dpkg_options_parse_arg_int(cipaction, pipein);
	in = fdopen(infd, "r");
	if (in == NULL)
		ohshite(_("cannot open '%i' for stream"), infd);

	lno = 0;

	for (;;) {
		bool mode = false;
		int argc = 1;

		push_error_context();

		do {
			c = getc(in);
			if (c == '\n')
				lno++;
		} while (c != EOF && c_isspace(c));
		if (c == EOF)
			break;

		if (c == '#') {
			do {
				c = getc(in);
				if (c == '\n')
					lno++;
			} while (c != EOF && c != '\n');
			continue;
		}

		varbuf_reset(&linevb);
		do {
			varbuf_add_char(&linevb, c);
			c = getc(in);
			if (c == '\n')
				lno++;

			/* This isn't fully accurate, but overestimating
			 * can't hurt. */
			if (c_isspace(c))
				argc++;
		} while (c != EOF && c != '\n');
		if (c == EOF)
			ohshit(_("cannot read end of line after command at line %d: %s"),
			       lno, _("unexpected end of file"));

		if (!argc)
			continue;

		newargs = m_realloc(newargs, sizeof(const char *) * (argc + 1));
		argc = 1;
		ptr = linevb.buf;
		endptr = ptr + linevb.used + 1;
		skipchar = false;
		while (ptr < endptr) {
			if (skipchar) {
				skipchar = false;
			} else if (*ptr == '\\') {
				memmove(ptr, ptr + 1, linevb.used - (linevb.buf - ptr) - 1);
				endptr--;
				skipchar = true;
				continue;
			} else if (c_isspace(*ptr)) {
				if (mode == true) {
					*ptr = '\0';
					mode = false;
				}
			} else {
				if (mode == false) {
					newargs[argc] = ptr;
					argc++;
					mode = true;
				}
			}
			ptr++;
		}
		*ptr = '\0';
		newargs[argc++] = NULL;

		/* We strdup() each argument, but never free it, because the
		 * error messages contain references back to these strings.
		 * Freeing them, and reusing the memory, would make those
		 * error messages confusing, to say the least. */
		for (i = 1; i < argc; i++)
			if (newargs[i])
				newargs[i] = m_strdup(newargs[i]);
		endargs = newargs;

		setaction(NULL, NULL);
		dpkg_options_parse((const char *const **)&endargs, cmdinfos, printforhelp);
		if (!cipaction)
			badusage(_("need an action option"));

		ret |= cipaction->action(endargs);

		fsys_hash_reset();

		pop_error_context(ehflag_normaltidy);
	}

	fclose(in);

	return ret;
}

int
main(int argc, const char *const *argv)
{
	char *force_string;
	int ret;

	dpkg_locales_init(PACKAGE);
	dpkg_program_init("dpkg");
	set_force_default(FORCE_ALL);
	dpkg_options_load(DPKG, cmdinfos);
	dpkg_options_parse(&argv, cmdinfos, printforhelp);

	debug(dbg_general, "root=%s admindir=%s",
	      dpkg_fsys_get_dir(), dpkg_db_get_dir());

	/* When running as root, make sure our primary group is also root, so
	 * that files created by maintainer scripts have correct ownership. */
	if (!in_force(FORCE_NON_ROOT) && getuid() == 0 && getgid() != 0)
		if (setgid(0) < 0)
			ohshite(_("cannot set primary group ID to root"));

	if (!cipaction)
		badusage(_("need an action option"));

	/* Always set environment, to avoid possible security risks. */
	if (setenv("DPKG_ADMINDIR", dpkg_db_get_dir(), 1) < 0)
		ohshite(_("cannot set environment for subprocesses"));
	if (setenv("DPKG_ROOT", dpkg_fsys_get_dir(), 1) < 0)
		ohshite(_("cannot set environment for subprocesses"));
	force_string = get_force_string();
	if (setenv("DPKG_FORCE", force_string, 1) < 0)
		ohshite(_("cannot set environment for subprocesses"));
	free(force_string);

	if (!f_triggers)
		f_triggers = (cipaction->arg_int == act_triggers && *argv) ? -1 : 1;

	if (can_invoke_hooks(cipaction->arg_int)) {
		run_invoke_hooks(cipaction->olong, &pre_invoke_hooks);
		run_status_loggers(&status_loggers);
	}

	ret = cipaction->action(argv);

	if (can_invoke_hooks(cipaction->arg_int))
		run_invoke_hooks(cipaction->olong, &post_invoke_hooks);

	free_invoke_hooks(&pre_invoke_hooks);
	free_invoke_hooks(&post_invoke_hooks);

	dpkg_program_done();
	dpkg_locales_done();

	return reportbroken_retexitstatus(ret);
}
