71c165780

Denis Vlasenko

2009-04-26

FAILED Duration: 34s

Subject

ifplugd: new applet by Maksym Kryzhanovskyy (xmaks AT email.cz) +3k code and 0.5k in messages. Most of the bloat due to compat :(

Binary

No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

Build Log

(log yok)

Commit Diff GitHub →

include/applets.h +1 -0 include/usage.h +41 -16 networking/Config.in +6 -0 networking/Kbuild +1 -0 networking/ifplugd.c +810 -0

include/applets.h+1 -0

@@ -189,6 +189,7 @@ IF_ID(APPLET(id, _BB_DIR_USR_BIN, _BB_SUID_NEVER))
	IF_IFCONFIG(APPLET(ifconfig, _BB_DIR_SBIN, _BB_SUID_NEVER))
	IF_IFUPDOWN(APPLET_ODDNAME(ifdown, ifupdown, _BB_DIR_SBIN, _BB_SUID_NEVER, ifdown))
	IF_IFENSLAVE(APPLET(ifenslave, _BB_DIR_SBIN, _BB_SUID_NEVER))
+	IF_IFPLUGD(APPLET(ifplugd, _BB_DIR_USR_BIN, _BB_SUID_NEVER))
	IF_IFUPDOWN(APPLET_ODDNAME(ifup, ifupdown, _BB_DIR_SBIN, _BB_SUID_NEVER, ifup))
	IF_INETD(APPLET(inetd, _BB_DIR_USR_SBIN, _BB_SUID_NEVER))
	IF_INIT(APPLET(init, _BB_DIR_SBIN, _BB_SUID_NEVER))

include/usage.h+41 -16

@@ -1727,21 +1727,46 @@
	/* "\n -r, --receive-slave Create a receive-only slave" */

	#define ifenslave_example_usage \
-	"To create a bond device, simply follow these three steps :\n" \
-	"- ensure that the required drivers are properly loaded :\n" \
+	"To create a bond device, simply follow these three steps:\n" \
+	"- ensure that the required drivers are properly loaded:\n" \
	" # modprobe bonding ; modprobe <3c59x\|eepro100\|pcnet32\|tulip\|...>\n" \
-	"- assign an IP address to the bond device :\n" \
+	"- assign an IP address to the bond device:\n" \
	" # ifconfig bond0 <addr> netmask <mask> broadcast <bcast>\n" \
-	"- attach all the interfaces you need to the bond device :\n" \
+	"- attach all the interfaces you need to the bond device:\n" \
	" # ifenslave bond0 eth0 eth1 eth2\n" \
	" If bond0 didn't have a MAC address, it will take eth0's. Then, all\n" \
	" interfaces attached AFTER this assignment will get the same MAC addr.\n\n" \
-	" To detach a dead interface without setting the bond device down :\n" \
-	" # ifenslave -d bond0 eth1\n\n" \
-	" To set the bond device down and automatically release all the slaves :\n" \
-	" # ifconfig bond0 down\n\n" \
-	" To change active slave :\n" \
-	" # ifenslave -c bond0 eth0\n" \
+	" To detach a dead interface without setting the bond device down:\n" \
+	" # ifenslave -d bond0 eth1\n\n" \
+	" To set the bond device down and automatically release all the slaves:\n" \
+	" # ifconfig bond0 down\n\n" \
+	" To change active slave:\n" \
+	" # ifenslave -c bond0 eth0\n" \
+
+	#define ifplugd_trivial_usage \
+	"[options]"
+	#define ifplugd_full_usage "\n\n" \
+	"Network interface plug detection daemon.\n\n" \
+	"Options:\n" \
+	"\n -n Do not daemonize" \
+	"\n -s Do not log to syslog" \
+	"\n -i IFACE Interface" \
+	"\n -f/-F Treat link detection error as link down/link up" \
+	"\n (otherwise exit on error)" \
+	"\n -a Do not up interface automatically" \
+	"\n -M Monitor creation/destruction of interface" \
+	"\n (otherwise it must exist)" \
+	"\n -r PROG Script to run" \
+	"\n -x ARG Extra argument for script" \
+	"\n -I Don't exit on nonzero exit code from script" \
+	"\n -p Don't run script on daemon startup" \
+	"\n -q Don't run script on daemon quit" \
+	"\n -l Run script on startup even if no cable is detected" \
+	"\n -t SECS Poll time in seconds" \
+	"\n -u SECS Delay before running script after link up" \
+	"\n -d SECS Delay after link down" \
+	"\n -m MODE API mode (mii, priv, ethtool, wlan, auto)" \
+	"\n -k Kill running daemon" \

	#define ifup_trivial_usage \
	"[-ain"IF_FEATURE_IFUPDOWN_MAPPING("m")"vf] ifaces..."
@@ -4346,17 +4371,17 @@
	"CMD: {add\|del\|change\|replace\|show}\n" \
	"\n" \
	"qdisc [ handle QHANDLE ] [ root \|"IF_FEATURE_TC_INGRESS(" ingress \|")" parent CLASSID ]\n" \
-	/* "\t[ estimator INTERVAL TIME_CONSTANT ]\n" */ \
-	"\t[ [ QDISC_KIND ] [ help \| OPTIONS ] ]\n" \
-	"\tQDISC_KIND := { [p\|b]fifo \| tbf \| prio \| cbq \| red \| etc. }\n" \
+	/* "[ estimator INTERVAL TIME_CONSTANT ]\n" */ \
+	" [ [ QDISC_KIND ] [ help \| OPTIONS ] ]\n" \
+	" QDISC_KIND := { [p\|b]fifo \| tbf \| prio \| cbq \| red \| etc. }\n" \
	"qdisc show [ dev STRING ]"IF_FEATURE_TC_INGRESS(" [ingress]")"\n" \
	"class [ classid CLASSID ] [ root \| parent CLASSID ]\n" \
-	"\t[ [ QDISC_KIND ] [ help \| OPTIONS ] ]\n" \
+	" [ [ QDISC_KIND ] [ help \| OPTIONS ] ]\n" \
	"class show [ dev STRING ] [ root \| parent CLASSID ]\n" \
	"filter [ pref PRIO ] [ protocol PROTO ]\n" \
	/* "\t[ estimator INTERVAL TIME_CONSTANT ]\n" */ \
-	"\t[ root \| classid CLASSID ] [ handle FILTERID ]\n" \
-	"\t[ [ FILTER_TYPE ] [ help \| OPTIONS ] ]\n" \
+	" [ root \| classid CLASSID ] [ handle FILTERID ]\n" \
+	" [ [ FILTER_TYPE ] [ help \| OPTIONS ] ]\n" \
	"filter show [ dev STRING ] [ root \| parent CLASSID ]"

	#define tcpsvd_trivial_usage \

networking/Config.in+6 -0

@@ -303,6 +303,12 @@ config IFENSLAVE
	Userspace application to bind several interfaces
	to a logical interface (use with kernel bonding driver).

+	config IFPLUGD
+	bool "ifplugd"
+	default n
+	help
+	Network interface plug detection daemon.
+
	config IFUPDOWN
	bool "ifupdown"
	default n

networking/Kbuild+1 -0

@@ -18,6 +18,7 @@ lib-$(CONFIG_HOSTNAME) += hostname.o
	lib-$(CONFIG_HTTPD) += httpd.o
	lib-$(CONFIG_IFCONFIG) += ifconfig.o interface.o
	lib-$(CONFIG_IFENSLAVE) += ifenslave.o interface.o
+	lib-$(CONFIG_IFPLUGD) += ifplugd.o
	lib-$(CONFIG_IFUPDOWN) += ifupdown.o
	lib-$(CONFIG_INETD) += inetd.o
	lib-$(CONFIG_IP) += ip.o

networking/ifplugd.c+810 -0

@@ -0,0 +1,810 @@
+	/* vi: set sw=4 ts=4: */
+	/*
+	* ifplugd for busybox
+	*
+	* Copyright (C) 2009
+	*
+	* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+	*/
+	#include "libbb.h"
+
+	#include <linux/if.h>
+	#include <linux/ethtool.h>
+	#include <net/ethernet.h>
+	#include <linux/netlink.h>
+	#include <linux/rtnetlink.h>
+	#include <linux/sockios.h>
+	#include <syslog.h>
+
+	#define __user
+	#include <linux/wireless.h>
+
+	#define IFPLUGD_ENV_PREVIOUS "IFPLUGD_PREVIOUS"
+	#define IFPLUGD_ENV_CURRENT "IFPLUGD_CURRENT"
+
+	enum {
+	FLAG_NO_AUTO = 1 << 0, // -a, Do not enable interface automatically
+	FLAG_NO_DAEMON = 1 << 1, // -n, Do not daemonize
+	FLAG_NO_SYSLOG = 1 << 2, // -s, Do not use syslog, use stderr instead
+	FLAG_IGNORE_FAIL = 1 << 3, // -f, Ignore detection failure, retry instead (failure is treated as DOWN)
+	FLAG_IGNORE_FAIL_POSITIVE = 1 << 4, // -F, Ignore detection failure, retry instead (failure is treated as UP)
+	FLAG_IFACE = 1 << 5, // -i, Specify ethernet interface
+	FLAG_RUN = 1 << 6, // -r, Specify program to execute
+	FLAG_IGNORE_RETVAL = 1 << 7, // -I, Don't exit on nonzero return value of program executed
+	FLAG_POLL_TIME = 1 << 8, // -t, Specify poll time in seconds
+	FLAG_DELAY_UP = 1 << 9, // -u, Specify delay for configuring interface
+	FLAG_DELAY_DOWN = 1 << 10, // -d, Specify delay for deconfiguring interface
+	FLAG_API_MODE = 1 << 11, // -m, Force API mode (mii, priv, ethtool, wlan, auto)
+	FLAG_NO_STARTUP = 1 << 12, // -p, Don't run script on daemon startup
+	FLAG_NO_SHUTDOWN = 1 << 13, // -q, Don't run script on daemon quit
+	FLAG_INITIAL_DOWN = 1 << 14, // -l, Run "down" script on startup if no cable is detected
+	FLAG_EXTRA_ARG = 1 << 15, // -x, Specify an extra argument for action script
+	FLAG_MONITOR = 1 << 16, // -M, Use interface monitoring
+	#if ENABLE_FEATURE_PIDFILE
+	FLAG_KILL = 1 << 17, // -k, Kill a running daemon
+	#endif
+	};
+	#if ENABLE_FEATURE_PIDFILE
+	# define OPTION_STR "+ansfFi:r:It:u:d:m:pqlx:Mk"
+	#else
+	# define OPTION_STR "+ansfFi:r:It:u:d:m:pqlx:M"
+	#endif
+
+	enum { // api mode
+	API_AUTO = 'a',
+	API_ETHTOOL = 'e',
+	API_MII = 'm',
+	API_PRIVATE = 'p',
+	API_WLAN = 'w',
+	API_IFF = 'i',
+	};
+
+	enum { // interface status
+	IFSTATUS_ERR = -1,
+	IFSTATUS_DOWN = 0,
+	IFSTATUS_UP = 1,
+	};
+
+	enum { // constant fds
+	ioctl_fd = 3,
+	netlink_fd = 4,
+	};
+
+	struct globals {
+	smallint iface_last_status;
+	smallint iface_exists;
+
+	/* Used in getopt32, must have sizeof == sizeof(int) */
+	unsigned poll_time;
+	unsigned delay_up;
+	unsigned delay_down;
+
+	const char *iface;
+	const char *api_mode;
+	const char *script_name;
+	const char *extra_arg;
+
+	smallint (*detect_link_func)(void);
+	smallint (*cached_detect_link_func)(void);
+	};
+	#define G (*ptr_to_globals)
+	#define INIT_G() do { \
+	SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
+	G.iface_last_status = -1; \
+	G.iface_exists = 1; \
+	G.poll_time = 1; \
+	G.delay_down = 5; \
+	G.iface = "eth0"; \
+	G.api_mode = "a"; \
+	G.script_name = "/etc/ifplugd/ifplugd.action"; \
+	} while (0)
+
+
+	static int run_script(const char *action)
+	{
+	pid_t pid;
+	int r;
+
+	bb_error_msg("executing '%s %s %s'", G.script_name, G.iface, action);
+
+	#if 1
+	pid = vfork();
+	if (pid < 0) {
+	bb_perror_msg("fork");
+	return -1;
+	}
+
+	if (pid == 0) {
+	/* child */
+	execlp(G.script_name, G.script_name, G.iface, action, G.extra_arg, NULL);
+	bb_perror_msg_and_die("can't execute '%s'", G.script_name);
+	}
+
+	/* parent */
+	wait(&r);
+	r = WEXITSTATUS(r);
+
+	bb_error_msg("exit code: %u", r);
+	return (option_mask32 & FLAG_IGNORE_RETVAL) ? 0 : r;
+
+	#else /* insanity */
+
+	struct fd_pair pipe_pair;
+	char buf[256];
+	int i = 0;
+
+	xpiped_pair(pipe_pair);
+
+	pid = vfork();
+	if (pid < 0) {
+	bb_perror_msg("fork");
+	return -1;
+	}
+
+	/* child */
+	if (pid == 0) {
+	xmove_fd(pipe_pair.wr, 1);
+	xdup2(1, 2);
+	if (pipe_pair.rd > 2)
+	close(pipe_pair.rd);
+
+	// umask(0022); // Set up a sane umask
+
+	execlp(G.script_name, G.script_name, G.iface, action, G.extra_arg, NULL);
+	_exit(EXIT_FAILURE);
+	}
+
+	/* parent */
+	close(pipe_pair.wr);
+
+	while (1) {
+	if (bb_got_signal && bb_got_signal != SIGCHLD) {
+	bb_error_msg("killing child");
+	kill(pid, SIGTERM);
+	bb_got_signal = 0;
+	break;
+	}
+
+	r = read(pipe_pair.rd, &buf[i], 1);
+
+	if (buf[i] == '\n' \|\| i == sizeof(buf)-2 \|\| r != 1) {
+	if (r == 1 && buf[i] != '\n')
+	i++;
+
+	buf[i] = '\0';
+
+	if (i > 0)
+	bb_error_msg("client: %s", buf);
+
+	i = 0;
+	} else {
+	i++;
+	}
+
+	if (r != 1)
+	break;
+	}
+
+	close(pipe_pair.rd);
+
+	wait(&r);
+
+	if (!WIFEXITED(r) \|\| WEXITSTATUS(r) != 0) {
+	bb_error_msg("program execution failed, return value is %i",
+	WEXITSTATUS(r));
+	return option_mask32 & FLAG_IGNORE_RETVAL ? 0 : WEXITSTATUS(r);
+	}
+	bb_error_msg("program executed successfully");
+	return 0;
+	#endif
+	}
+
+	static int network_ioctl(int request, void* data)
+	{
+	return ioctl(ioctl_fd, request, data);
+	}
+
+	static void set_ifreq_to_ifname(struct ifreq *ifreq)
+	{
+	memset(ifreq, 0, sizeof(struct ifreq));
+	strncpy(ifreq->ifr_name, G.iface, IFNAMSIZ);
+	}
+
+	static const char *strstatus(int status)
+	{
+	if (status == IFSTATUS_ERR)
+	return "error";
+	return "down\0up" + (status * 5);
+	}
+
+	static void up_iface(void)
+	{
+	struct ifreq ifrequest;
+
+	if (!G.iface_exists)
+	return;
+
+	set_ifreq_to_ifname(&ifrequest);
+	if (network_ioctl(SIOCGIFFLAGS, &ifrequest) < 0) {
+	bb_perror_msg("can't %cet interface flags", 'g');
+	G.iface_exists = 0;
+	return;
+	}
+
+	if (!(ifrequest.ifr_flags & IFF_UP)) {
+	ifrequest.ifr_flags \|= IFF_UP;
+	/* Let user know we mess up with interface */
+	bb_error_msg("upping interface");
+	if (network_ioctl(SIOCSIFFLAGS, &ifrequest) < 0)
+	bb_perror_msg_and_die("can't %cet interface flags", 's');
+	}
+
+	#if 0 /* why do we mess with IP addr? It's not our business */
+	if (network_ioctl(SIOCGIFADDR, &ifrequest) < 0) {
+	bb_error_msg("can't get interface address");
+	} else if (ifrequest.ifr_addr.sa_family != AF_INET) {
+	bb_perror_msg("The interface is not IP-based");
+	} else {
+	((struct sockaddr_in*)(&ifrequest.ifr_addr))->sin_addr.s_addr = INADDR_ANY;
+	if (network_ioctl(SIOCSIFADDR, &ifrequest) < 0)
+	bb_perror_msg("can't set interface address");
+	}
+	if (network_ioctl(SIOCGIFFLAGS, &ifrequest) < 0) {
+	bb_perror_msg("can't get interface flags");
+	return;
+	}
+	#endif
+	}
+
+	static void maybe_up_new_iface(void)
+	{
+	if (!(option_mask32 & FLAG_NO_AUTO))
+	up_iface();
+
+	#if 0 /* bloat */
+	struct ifreq ifrequest;
+	struct ethtool_drvinfo driver_info;
+
+	set_ifreq_to_ifname(&ifrequest);
+	driver_info.cmd = ETHTOOL_GDRVINFO;
+	ifrequest.ifr_data = &driver_info;
+	if (network_ioctl(SIOCETHTOOL, &ifrequest) == 0) {
+	char buf[sizeof("/xx:xx:xx:xx:xx:xx")];
+
+	/* Get MAC */
+	buf[0] = '\0';
+	set_ifreq_to_ifname(&ifrequest);
+	if (network_ioctl(SIOCGIFHWADDR, &ifrequest) == 0) {
+	sprintf(buf, "/%02X:%02X:%02X:%02X:%02X:%02X",
+	(uint8_t)(ifrequest.ifr_hwaddr.sa_data[0]),
+	(uint8_t)(ifrequest.ifr_hwaddr.sa_data[1]),
+	(uint8_t)(ifrequest.ifr_hwaddr.sa_data[2]),
+	(uint8_t)(ifrequest.ifr_hwaddr.sa_data[3]),
+	(uint8_t)(ifrequest.ifr_hwaddr.sa_data[4]),
+	(uint8_t)(ifrequest.ifr_hwaddr.sa_data[5]));
+	}
+
+	bb_error_msg("Using interface %s%s with driver<%s> (version: %s)",
+	G.iface, buf, driver_info.driver, driver_info.version);
+	}
+	#endif
+
+	G.cached_detect_link_func = NULL;
+	}
+
+	static smallint detect_link_mii(void)
+	{
+	struct ifreq ifreq;
+
+	set_ifreq_to_ifname(&ifreq);
+
+	if (network_ioctl(SIOCGMIIPHY, &ifreq) < 0) {
+	bb_perror_msg("SIOCGMIIPHY failed");
+	return IFSTATUS_ERR;
+	}
+
+	((unsigned short*)&ifreq.ifr_data)[1] = 1;
+
+	if (network_ioctl(SIOCGMIIREG, &ifreq) < 0) {
+	bb_perror_msg("SIOCGMIIREG failed");
+	return IFSTATUS_ERR;
+	}
+
+	return (((unsigned short*)&ifreq.ifr_data)[3] & 0x0004) ?
+	IFSTATUS_UP : IFSTATUS_DOWN;
+	}
+
+	static smallint detect_link_priv(void)
+	{
+	struct ifreq ifreq;
+
+	set_ifreq_to_ifname(&ifreq);
+
+	if (network_ioctl(SIOCDEVPRIVATE, &ifreq) < 0) {
+	bb_perror_msg("SIOCDEVPRIVATE failed");
+	return IFSTATUS_ERR;
+	}
+
+	((unsigned short*) &ifreq.ifr_data)[1] = 1;
+
+	if (network_ioctl(SIOCDEVPRIVATE+1, &ifreq) < 0) {
+	bb_perror_msg("SIOCDEVPRIVATE+1 failed");
+	return IFSTATUS_ERR;
+	}
+
+	return (((unsigned short*)&ifreq.ifr_data)[3] & 0x0004) ?
+	IFSTATUS_UP : IFSTATUS_DOWN;
+	}
+
+	static smallint detect_link_ethtool(void)
+	{
+	struct ifreq ifreq;
+	struct ethtool_value edata;
+
+	set_ifreq_to_ifname(&ifreq);
+
+	edata.cmd = ETHTOOL_GLINK;
+	ifreq.ifr_data = &edata;
+
+	if (network_ioctl(SIOCETHTOOL, &ifreq) < 0) {
+	bb_perror_msg("ETHTOOL_GLINK failed");
+	return IFSTATUS_ERR;
+	}
+
+	return edata.data ? IFSTATUS_UP : IFSTATUS_DOWN;
+	}
+
+	static smallint detect_link_iff(void)
+	{
+	struct ifreq ifreq;
+
+	set_ifreq_to_ifname(&ifreq);
+
+	if (network_ioctl(SIOCGIFFLAGS, &ifreq) < 0) {
+	bb_perror_msg("SIOCGIFFLAGS failed");
+	return IFSTATUS_ERR;
+	}
+
+	return (ifreq.ifr_flags & IFF_RUNNING) ? IFSTATUS_UP : IFSTATUS_DOWN;
+	}
+
+	static smallint detect_link_wlan(void)
+	{
+	struct iwreq iwrequest;
+	uint8_t mac[ETH_ALEN];
+
+	memset(&iwrequest, 0, sizeof(struct iwreq));
+	strncpy(iwrequest.ifr_ifrn.ifrn_name, G.iface, IFNAMSIZ);
+
+	if (network_ioctl(SIOCGIWAP, &iwrequest) < 0) {
+	bb_perror_msg("SIOCGIWAP failed");
+	return IFSTATUS_ERR;
+	}
+
+	memcpy(mac, &(iwrequest.u.ap_addr.sa_data), ETH_ALEN);
+
+	if (mac[0] == 0xFF \|\| mac[0] == 0x44 \|\| mac[0] == 0x00) {
+	for (int i = 1; i < ETH_ALEN; ++i) {
+	if (mac[i] != mac[0])
+	return IFSTATUS_UP;
+	}
+	return IFSTATUS_DOWN;
+	}
+
+	return IFSTATUS_UP;
+	}
+
+	static smallint detect_link_auto(void)
+	{
+	const char *method;
+	smallint iface_status;
+	smallint sv_logmode;
+
+	if (G.cached_detect_link_func) {
+	iface_status = G.cached_detect_link_func();
+	if (iface_status != IFSTATUS_ERR)
+	return iface_status;
+	}
+
+	sv_logmode = logmode;
+	logmode = LOGMODE_NONE;
+
+	iface_status = detect_link_ethtool();
+	if (iface_status != IFSTATUS_ERR) {
+	G.cached_detect_link_func = detect_link_ethtool;
+	method = "SIOCETHTOOL";
+	found_method:
+	logmode = sv_logmode;
+	bb_error_msg("using %s detection mode", method);
+	return iface_status;
+	}
+
+	iface_status = detect_link_mii();
+	if (iface_status != IFSTATUS_ERR) {
+	G.cached_detect_link_func = detect_link_mii;
+	method = "SIOCGMIIPHY";
+	goto found_method;
+	}
+
+	iface_status = detect_link_priv();
+	if (iface_status != IFSTATUS_ERR) {
+	G.cached_detect_link_func = detect_link_priv;
+	method = "SIOCDEVPRIVATE";
+	goto found_method;
+	}
+
+	iface_status = detect_link_wlan();
+	if (iface_status != IFSTATUS_ERR) {
+	G.cached_detect_link_func = detect_link_wlan;
+	method = "wireless extension";
+	goto found_method;
+	}
+
+	iface_status = detect_link_iff();
+	if (iface_status != IFSTATUS_ERR) {
+	G.cached_detect_link_func = detect_link_iff;
+	method = "IFF_RUNNING";
+	goto found_method;
+	}
+
+	logmode = sv_logmode;
+	return iface_status; /* IFSTATUS_ERR */
+	}
+
+	static smallint detect_link(void)
+	{
+	smallint status;
+
+	if (!G.iface_exists)
+	return (option_mask32 & FLAG_MONITOR) ? IFSTATUS_DOWN : IFSTATUS_ERR;
+
+	#if 0
+	/* Why? This behavior makes it hard to temporary down the iface.
+	* It makes a bit more sense to do only in maybe_up_new_iface.
+	* OTOH, maybe detect_link_wlan needs this. Then it should be done
+	* _only_ there.
+	*/
+	if (!(option_mask32 & FLAG_NO_AUTO))
+	up_iface();
+	#endif
+
+	status = G.detect_link_func();
+	if (status == IFSTATUS_ERR) {
+	if (option_mask32 & FLAG_IGNORE_FAIL)
+	status = IFSTATUS_DOWN;
+	if (option_mask32 & FLAG_IGNORE_FAIL_POSITIVE)
+	status = IFSTATUS_UP;
+	}
+
+	if (status == IFSTATUS_ERR
+	&& G.detect_link_func == detect_link_auto
+	) {
+	bb_error_msg("failed to detect link status");
+	}
+
+	if (status != G.iface_last_status) {
+	//TODO: is it safe to repeatedly do this?
+	setenv(IFPLUGD_ENV_PREVIOUS, strstatus(G.iface_last_status), 1);
+	setenv(IFPLUGD_ENV_CURRENT, strstatus(status), 1);
+	G.iface_last_status = status;
+	}
+
+	return status;
+	}
+
+	static NOINLINE int check_existence_through_netlink(void)
+	{
+	char replybuf[1024];
+
+	while (1) {
+	struct nlmsghdr *mhdr;
+	ssize_t bytes;
+
+	bytes = recv(netlink_fd, &replybuf, sizeof(replybuf), MSG_DONTWAIT);
+	if (bytes < 0) {
+	if (errno == EAGAIN)
+	return G.iface_exists;
+	if (errno == EINTR)
+	continue;
+
+	bb_perror_msg("netlink: recv");
+	return -1;
+	}
+
+	mhdr = (struct nlmsghdr*)replybuf;
+	while (bytes > 0) {
+	if (!NLMSG_OK(mhdr, bytes)
+	\|\| bytes < sizeof(struct nlmsghdr)
+	\|\| bytes < mhdr->nlmsg_len
+	) {
+	bb_error_msg("netlink packet too small or truncated");
+	return -1;
+	}
+
+	if (mhdr->nlmsg_type == RTM_NEWLINK \|\| mhdr->nlmsg_type == RTM_DELLINK) {
+	struct rtattr *attr;
+	struct ifinfomsg *imsg;
+	int attr_len;
+
+	imsg = NLMSG_DATA(mhdr);
+
+	if (mhdr->nlmsg_len < NLMSG_LENGTH(sizeof(struct ifinfomsg))) {
+	bb_error_msg("netlink packet too small or truncated");
+	return -1;
+	}
+
+	attr = (struct rtattr)((char)imsg + NLMSG_ALIGN(sizeof(struct ifinfomsg)));
+	attr_len = NLMSG_PAYLOAD(mhdr, sizeof(struct ifinfomsg));
+
+	while (RTA_OK(attr, attr_len)) {
+	if (attr->rta_type == IFLA_IFNAME) {
+	char ifname[IFNAMSIZ + 1];
+	int len = RTA_PAYLOAD(attr);
+
+	if (len > IFNAMSIZ)
+	len = IFNAMSIZ;
+	memcpy(ifname, RTA_DATA(attr), len);
+	if (strcmp(G.iface, ifname) == 0) {
+	G.iface_exists = (mhdr->nlmsg_type == RTM_NEWLINK);
+	}
+	}
+	attr = RTA_NEXT(attr, attr_len);
+	}
+	}
+
+	mhdr = NLMSG_NEXT(mhdr, bytes);
+	}
+	}
+
+	return G.iface_exists;
+	}
+
+	static NOINLINE int netlink_open(void)
+	{
+	int fd;
+	struct sockaddr_nl addr;
+
+	fd = xsocket(PF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
+
+	memset(&addr, 0, sizeof(addr));
+	addr.nl_family = AF_NETLINK;
+	addr.nl_groups = RTMGRP_LINK;
+	addr.nl_pid = getpid();
+
+	xbind(fd, (struct sockaddr*)&addr, sizeof(addr));
+
+	return fd;
+	}
+
+	static NOINLINE pid_t read_pid(const char *filename)
+	{
+	int len;
+	char buf[128];
+
+	len = open_read_close(filename, buf, 127);
+	if (len > 0) {
+	buf[len] = '\0';
+	/* returns ULONG_MAX on error => -1 */
+	return bb_strtoul(buf, NULL, 10);
+	}
+	return 0;
+	}
+
+	int ifplugd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+	int ifplugd_main(int argc UNUSED_PARAM, char **argv)
+	{
+	int iface_status;
+	int delay_time;
+	const char *iface_status_str;
+	struct pollfd netlink_pollfd[1];
+	unsigned opts;
+	#if ENABLE_FEATURE_PIDFILE
+	char *pidfile_name;
+	pid_t pid_from_pidfile;
+	#endif
+
+	INIT_G();
+
+	opt_complementary = "t+:u+:d+";
+	opts = getopt32(argv, OPTION_STR,
+	&G.iface, &G.script_name, &G.poll_time, &G.delay_up,
+	&G.delay_down, &G.api_mode, &G.extra_arg);
+
+	applet_name = xasprintf("ifplugd(%s)", G.iface);
+
+	#if ENABLE_FEATURE_PIDFILE
+	pidfile_name = xasprintf(_PATH_VARRUN"ifplugd.%s.pid", G.iface);
+	pid_from_pidfile = read_pid(pidfile_name);
+
+	if (opts & FLAG_KILL) {
+	if (pid_from_pidfile > 0)
+	kill(pid_from_pidfile, SIGQUIT);
+	return EXIT_SUCCESS;
+	}
+
+	if (pid_from_pidfile > 0 && kill(pid_from_pidfile, 0) == 0)
+	bb_error_msg_and_die("daemon already running");
+	#endif
+
+	switch (G.api_mode[0]) {
+	case API_AUTO:
+	G.detect_link_func = detect_link_auto;
+	break;
+	case API_ETHTOOL:
+	G.detect_link_func = detect_link_ethtool;
+	break;
+	case API_MII:
+	G.detect_link_func = detect_link_mii;
+	break;
+	case API_PRIVATE:
+	G.detect_link_func = detect_link_priv;
+	break;
+	case API_WLAN:
+	G.detect_link_func = detect_link_wlan;
+	break;
+	case API_IFF:
+	G.detect_link_func = detect_link_iff;
+	break;
+	default:
+	bb_error_msg_and_die("unknown API mode '%s'", G.api_mode);
+	}
+
+	if (!(opts & FLAG_NO_DAEMON))
+	bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
+
+	xmove_fd(xsocket(AF_INET, SOCK_DGRAM, 0), ioctl_fd);
+	if (opts & FLAG_MONITOR) {
+	xmove_fd(netlink_open(), netlink_fd);
+	}
+
+	write_pidfile(pidfile_name);
+
+	/* this can't be moved before socket creation */
+	if (!(opts & FLAG_NO_SYSLOG)) {
+	openlog(applet_name, 0, LOG_DAEMON);
+	logmode \|= LOGMODE_SYSLOG;
+	}
+
+	bb_signals(0
+	\| (1 << SIGINT )
+	\| (1 << SIGTERM)
+	\| (1 << SIGQUIT)
+	\| (1 << SIGHUP ) /* why we ignore it? */
+	/* \| (1 << SIGCHLD) - run_script does not use it anymore */
+	, record_signo);
+
+	bb_error_msg("started: %s", bb_banner);
+
+	if (opts & FLAG_MONITOR) {
+	struct ifreq ifrequest;
+	set_ifreq_to_ifname(&ifrequest);
+	G.iface_exists = (network_ioctl(SIOCGIFINDEX, &ifrequest) == 0);
+	}
+
+	if (G.iface_exists)
+	maybe_up_new_iface();
+
+	iface_status = detect_link();
+	if (iface_status == IFSTATUS_ERR)
+	goto exiting;
+	iface_status_str = strstatus(iface_status);
+
+	if (opts & FLAG_MONITOR) {
+	bb_error_msg("interface %s",
+	G.iface_exists ? "exists"
+	: "doesn't exist, waiting");
+	}
+	/* else we assume it always exists, but don't mislead user
+	* by potentially lying that it really exists */
+
+	if (G.iface_exists) {
+	bb_error_msg("link is %s", iface_status_str);
+	}
+
+	if ((!(opts & FLAG_NO_STARTUP)
+	&& iface_status == IFSTATUS_UP
+	)
+	\|\| (opts & FLAG_INITIAL_DOWN)
+	) {
+	if (run_script(iface_status_str) != 0)
+	goto exiting;
+	}
+
+	/* Main loop */
+	netlink_pollfd[0].fd = netlink_fd;
+	netlink_pollfd[0].events = POLLIN;
+	delay_time = 0;
+	while (1) {
+	int iface_status_old;
+	int iface_exists_old;
+
+	switch (bb_got_signal) {
+	case SIGINT:
+	case SIGTERM:
+	bb_got_signal = 0;
+	goto cleanup;
+	case SIGQUIT:
+	bb_got_signal = 0;
+	goto exiting;
+	default:
+	bb_got_signal = 0;
+	break;
+	}
+
+	if (poll(netlink_pollfd,
+	(opts & FLAG_MONITOR) ? 1 : 0,
+	G.poll_time * 1000
+	) < 0
+	) {
+	if (errno == EINTR)
+	continue;
+	bb_perror_msg("poll");
+	goto exiting;
+	}
+
+	iface_status_old = iface_status;
+	iface_exists_old = G.iface_exists;
+
+	if ((opts & FLAG_MONITOR)
+	&& (netlink_pollfd[0].revents & POLLIN)
+	) {
+	G.iface_exists = check_existence_through_netlink();
+	if (G.iface_exists < 0) /* error */
+	goto exiting;
+	if (iface_exists_old != G.iface_exists) {
+	bb_error_msg("interface %sappeared",
+	G.iface_exists ? "" : "dis");
+	if (G.iface_exists)
+	maybe_up_new_iface();
+	}
+	}
+
+	/* note: if !G.iface_exists, returns DOWN */
+	iface_status = detect_link();
+	if (iface_status == IFSTATUS_ERR) {
+	if (!(opts & FLAG_MONITOR))
+	goto exiting;
+	iface_status = IFSTATUS_DOWN;
+	}
+	iface_status_str = strstatus(iface_status);
+
+	if (iface_status_old != iface_status) {
+	bb_error_msg("link is %s", iface_status_str);
+
+	if (delay_time) {
+	/* link restored its old status before
+	* we run script. don't run the script: */
+	delay_time = 0;
+	} else {
+	delay_time = monotonic_sec();
+	if (iface_status == IFSTATUS_UP)
+	delay_time += G.delay_up;
+	if (iface_status == IFSTATUS_DOWN)
+	delay_time += G.delay_down;
+	if (delay_time == 0)
+	delay_time++;
+	}
+	}
+
+	if (delay_time && (int)(monotonic_sec() - delay_time) >= 0) {
+	delay_time = 0;
+	if (run_script(iface_status_str) != 0)
+	goto exiting;
+	}
+	} /* while (1) */
+
+	cleanup:
+	if (!(opts & FLAG_NO_SHUTDOWN)
+	&& (iface_status == IFSTATUS_UP
+	\|\| (iface_status == IFSTATUS_DOWN && delay_time)
+	)
+	) {
+	setenv(IFPLUGD_ENV_PREVIOUS, strstatus(iface_status), 1);
+	setenv(IFPLUGD_ENV_CURRENT, strstatus(-1), 1);
+	run_script("down\0up"); /* reusing string */
+	}
+
+	exiting:
+	remove_pidfile(pidfile_name);
+	bb_error_msg_and_die("exiting");
+	}