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  /*
   * simple ACPI events listener
   *
   * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
   *
   * Licensed under GPLv2, see file LICENSE in this source tree.
   */
  
  //usage:#define acpid_trivial_usage
  //usage:       "[-df] [-c CONFDIR] [-l LOGFILE] [-a ACTIONFILE] [-M MAPFILE] [-e PROC_EVENT_FILE] [-p PIDFILE]"
  //usage:#define acpid_full_usage "\n\n"
  //usage:       "Listen to ACPI events and spawn specific helpers on event arrival\n"
  //usage:     "\n	-d	Log to stderr, not log file (implies -f)"
  //usage:     "\n	-f	Run in foreground"
  //usage:     "\n	-c DIR	Config directory [/etc/acpi]"
  //usage:     "\n	-e FILE	/proc event file [/proc/acpi/event]"
  //usage:     "\n	-l FILE	Log file [/var/log/acpid.log]"
  //usage:     "\n	-p FILE	Pid file [/var/run/acpid.pid]"
  //usage:     "\n	-a FILE	Action file [/etc/acpid.conf]"
  //usage:     "\n	-M FILE Map file [/etc/acpi.map]"
  //usage:	IF_FEATURE_ACPID_COMPAT(
  //usage:     "\n\nAccept and ignore compatibility options -g -m -s -S -v"
  //usage:	)
  //usage:
  //usage:#define acpid_example_usage
  //usage:       "Without -e option, acpid uses all /dev/input/event* files\n"
  //usage:       "# acpid\n"
  //usage:       "# acpid -l /var/log/my-acpi-log\n"
  //usage:       "# acpid -e /proc/acpi/event\n"
  
  #include "libbb.h"
  #include <syslog.h>
  #include <linux/input.h>
  
  #ifndef EV_SW
  # define EV_SW         0x05
  #endif
  #ifndef EV_KEY
  # define EV_KEY        0x01
  #endif
  #ifndef SW_LID
  # define SW_LID        0x00
  #endif
  #ifndef SW_RFKILL_ALL
  # define SW_RFKILL_ALL 0x03
  #endif
  #ifndef KEY_POWER
  # define KEY_POWER      116     /* SC System Power Down */
  #endif
  #ifndef KEY_SLEEP
  # define KEY_SLEEP      142     /* SC System Sleep */
  #endif
  
  enum {
  	OPT_c = (1 << 0),
  	OPT_d = (1 << 1),
  	OPT_e = (1 << 2),
  	OPT_f = (1 << 3),
  	OPT_l = (1 << 4),
  	OPT_a = (1 << 5),
  	OPT_M = (1 << 6),
  	OPT_p = (1 << 7) * ENABLE_FEATURE_PIDFILE,
  };
  
  struct acpi_event {
  	const char *s_type;
  	uint16_t n_type;
  	const char *s_code;
  	uint16_t n_code;
  	uint32_t value;
  	const char *desc;
  };
  
  static const struct acpi_event f_evt_tab[] = {
  	{ "EV_KEY", 0x01, "KEY_POWER", 116, 1, "button/power PWRF 00000080" },
  	{ "EV_KEY", 0x01, "KEY_POWER", 116, 1, "button/power PWRB 00000080" },
  	{ "EV_SW", 0x05, "SW_LID", 0x00, 1, "button/lid LID0 00000080" },
  };
  
  struct acpi_action {
  	const char *key;
  	const char *action;
  };
  
  static const struct acpi_action f_act_tab[] = {
  	{ "PWRF", "PWRF/00000080" },
  	{ "LID0", "LID/00000080" },
  };
  
  struct globals {
  	struct acpi_action *act_tab;
  	int n_act;
  	struct acpi_event *evt_tab;
  	int n_evt;
  } FIX_ALIASING;
  #define G (*ptr_to_globals)
  #define act_tab         (G.act_tab)
  #define n_act           (G.n_act  )
  #define evt_tab         (G.evt_tab)
  #define n_evt           (G.n_evt  )
  #define INIT_G() do { \
  	SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
  } while (0)
  
  /*
   * acpid listens to ACPI events coming either in textual form
   * from /proc/acpi/event (though it is marked deprecated,
   * it is still widely used and _is_ a standard) or in binary form
   * from specified evdevs (just use /dev/input/event*).
   * It parses the event to retrieve ACTION and a possible PARAMETER.
   * It then spawns /etc/acpi/<ACTION>[/<PARAMETER>] either via run-parts
   * (if the resulting path is a directory) or directly.
   * If the resulting path does not exist it logs it via perror
   * and continues listening.
   */
  
  static void process_event(const char *event)
  {
  	struct stat st;
  	char *handler = xasprintf("./%s", event);
  	const char *args[] = { "run-parts", handler, NULL };
  
  	// log the event
  	bb_error_msg("%s", event);
  
  	// spawn handler
  	// N.B. run-parts would require scripts to have #!/bin/sh
  	// handler is directory? -> use run-parts
  	// handler is file? -> run it directly
  	if (0 == stat(event, &st))
  		spawn((char **)args + (0==(st.st_mode & S_IFDIR)));
  	else
  		bb_simple_perror_msg(event);
  
  	free(handler);
  }
  
  static const char *find_action(struct input_event *ev, const char *buf)
  {
  	const char *action = NULL;
  	int i;
  
  	// map event
  	for (i = 0; i < n_evt; i++) {
  		if (ev) {
  			if (ev->type == evt_tab[i].n_type && ev->code == evt_tab[i].n_code && ev->value == evt_tab[i].value) {
  				action = evt_tab[i].desc;
  				break;
  			}
  		}
  
  		if (buf) {
  			if (is_prefixed_with(evt_tab[i].desc, buf)) {
  				action = evt_tab[i].desc;
  				break;
  			}
  		}
  	}
  
  	// get action
  	if (action) {
  		for (i = 0; i < n_act; i++) {
  			if (strstr(action, act_tab[i].key)) {
  				action = act_tab[i].action;
  				break;
  			}
  		}
  	}
  
  	return action;
  }
  
  static void parse_conf_file(const char *filename)
  {
  	parser_t *parser;
  	char *tokens[2];
  
  	parser = config_open2(filename, fopen_for_read);
  
  	if (parser) {
  		while (config_read(parser, tokens, 2, 2, "# \t", PARSE_NORMAL)) {
  			act_tab = xrealloc_vector(act_tab, 1, n_act);
  			act_tab[n_act].key = xstrdup(tokens[0]);
  			act_tab[n_act].action = xstrdup(tokens[1]);
  			n_act++;
  		}
  		config_close(parser);
  	} else {
  		act_tab = (void*)f_act_tab;
  		n_act = ARRAY_SIZE(f_act_tab);
  	}
  }
  
  static void parse_map_file(const char *filename)
  {
  	parser_t *parser;
  	char *tokens[6];
  
  	parser = config_open2(filename, fopen_for_read);
  
  	if (parser) {
  		while (config_read(parser, tokens, 6, 6, "# \t", PARSE_NORMAL)) {
  			evt_tab = xrealloc_vector(evt_tab, 1, n_evt);
  			evt_tab[n_evt].s_type = xstrdup(tokens[0]);
  			evt_tab[n_evt].n_type = xstrtou(tokens[1], 16);
  			evt_tab[n_evt].s_code = xstrdup(tokens[2]);
  			evt_tab[n_evt].n_code = xatou16(tokens[3]);
  			evt_tab[n_evt].value = xatoi_positive(tokens[4]);
  			evt_tab[n_evt].desc = xstrdup(tokens[5]);
  			n_evt++;
  		}
  		config_close(parser);
  	} else {
  		evt_tab = (void*)f_evt_tab;
  		n_evt = ARRAY_SIZE(f_evt_tab);
  	}
  }
  
  /*
   * acpid [-c conf_dir] [-r conf_file ] [-a map_file ] [-l log_file] [-e proc_event_file]
   */
  
  int acpid_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  int acpid_main(int argc UNUSED_PARAM, char **argv)
  {
  	int nfd;
  	int opts;
  	struct pollfd *pfd;
  	const char *opt_dir = "/etc/acpi";
  	const char *opt_input = "/dev/input/event";
  	const char *opt_logfile = "/var/log/acpid.log";
  	const char *opt_action = "/etc/acpid.conf";
  	const char *opt_map = "/etc/acpi.map";
  #if ENABLE_FEATURE_PIDFILE
  	const char *opt_pidfile = CONFIG_PID_FILE_PATH "/acpid.pid";
  #endif
  
  	INIT_G();
  
  	opt_complementary = "df:e--e";
  	opts = getopt32(argv, "c:de:fl:a:M:" IF_FEATURE_PIDFILE("p:") IF_FEATURE_ACPID_COMPAT("g:m:s:S:v"),
  		&opt_dir, &opt_input, &opt_logfile, &opt_action, &opt_map
  		IF_FEATURE_PIDFILE(, &opt_pidfile)
  		IF_FEATURE_ACPID_COMPAT(, NULL, NULL, NULL, NULL)
  	);
  
  	if (!(opts & OPT_f)) {
  		/* No -f "Foreground", we go to background */
  		bb_daemonize_or_rexec(DAEMON_CLOSE_EXTRA_FDS, argv);
  	}
  
  	if (!(opts & OPT_d)) {
  		/* No -d "Debug", we log to log file.
  		 * This includes any output from children.
  		 */
  		xmove_fd(xopen(opt_logfile, O_WRONLY | O_CREAT | O_APPEND), STDOUT_FILENO);
  		xdup2(STDOUT_FILENO, STDERR_FILENO);
  		/* Also, acpid's messages (but not children) will go to syslog too */
  		openlog(applet_name, LOG_PID, LOG_DAEMON);
  		logmode = LOGMODE_SYSLOG | LOGMODE_STDIO;
  	}
  	/* else: -d "Debug", log is not redirected */
  
  	parse_conf_file(opt_action);
  	parse_map_file(opt_map);
  
  	xchdir(opt_dir);
  
  	/* We spawn children but don't wait for them. Prevent zombies: */
  	bb_signals((1 << SIGCHLD), SIG_IGN);
  	// If you enable this, (1) explain why, (2)
  	// make sure while(poll) loop below is still interruptible
  	// by SIGTERM et al:
  	//bb_signals(BB_FATAL_SIGS, record_signo);
  
  	pfd = NULL;
  	nfd = 0;
  	while (1) {
  		int fd;
  		char *dev_event;
  
  		dev_event = xasprintf((opts & OPT_e) ? "%s" : "%s%u", opt_input, nfd);
  		fd = open(dev_event, O_RDONLY | O_NONBLOCK);
  		if (fd < 0) {
  			if (nfd == 0)
  				bb_simple_perror_msg_and_die(dev_event);
  			break;
  		}
  		free(dev_event);
  		pfd = xrealloc_vector(pfd, 1, nfd);
  		pfd[nfd].fd = fd;
  		pfd[nfd].events = POLLIN;
  		nfd++;
  	}
  
  	write_pidfile(opt_pidfile);
  
  	while (safe_poll(pfd, nfd, -1) > 0) {
  		int i;
  		for (i = 0; i < nfd; i++) {
  			const char *event;
  
  			if (!(pfd[i].revents & POLLIN)) {
  				if (pfd[i].revents == 0)
  					continue; /* this fd has nothing */
  
  				/* Likely POLLERR, POLLHUP, POLLNVAL.
  				 * Do not listen on this fd anymore.
  				 */
  				close(pfd[i].fd);
  				nfd--;
  				for (; i < nfd; i++)
  					pfd[i].fd = pfd[i + 1].fd;
  				break; /* do poll() again */
  			}
  
  			event = NULL;
  			if (option_mask32 & OPT_e) {
  				char *buf;
  				int len;
  
  				buf = xmalloc_reads(pfd[i].fd, NULL);
  				/* buf = "button/power PWRB 00000080 00000000" */
  				len = strlen(buf) - 9;
  				if (len >= 0)
  					buf[len] = '\0';
  				event = find_action(NULL, buf);
  				free(buf);
  			} else {
  				struct input_event ev;
  
  				if (sizeof(ev) != full_read(pfd[i].fd, &ev, sizeof(ev)))
  					continue;
  
  				if (ev.value != 1 && ev.value != 0)
  					continue;
  
  				event = find_action(&ev, NULL);
  			}
  			if (!event)
  				continue;
  			/* spawn event handler */
  			process_event(event);
  		}
  	}
  
  	if (ENABLE_FEATURE_CLEAN_UP) {
  		while (nfd--)
  			close(pfd[nfd].fd);
  		free(pfd);
  	}
  	remove_pidfile(opt_pidfile);
  
  	return EXIT_SUCCESS;
  }
  