--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/sm-archive.cpp	Fri Mar 10 10:30:08 2006 -0800
@@ -0,0 +1,509 @@
+/*
+
+Copyright (c) 2004, 2005 Carl Byington - 510 Software Group, released
+under the GPL version 2 or any later version at your choice available at
+http://www.fsf.org/licenses/gpl.txt
+
+Based on a sample milter Copyright (c) 2000-2003 Sendmail, Inc. and its
+suppliers.	Inspired by the DCC by Rhyolite Software
+
+-p port  The port through which the MTA will connect to this milter.
+-t sec	 The timeout value.
+-c		 Check the config, and print a copy to stdout. Don't start the
+		 milter or do anything with the socket.
+-d		 increase debug level
+
+*/
+
+
+// from sendmail sample
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <errno.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+// needed for socket io
+#include <sys/ioctl.h>
+#include <net/if.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <netdb.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+
+// needed for thread
+#include <pthread.h>
+
+// needed for std c++ collections
+#include <set>
+#include <map>
+#include <list>
+
+// for the dns resolver
+#include <netinet/in.h>
+#include <arpa/nameser.h>
+#include <resolv.h>
+
+// misc stuff needed here
+#include <ctype.h>
+#include <syslog.h>
+#include <pwd.h>
+#include <sys/wait.h>	/* header for waitpid() and various macros */
+#include <signal.h> 	/* header for signal functions */
+
+#include "includes.h"
+
+static char* dnsbl_version="$Id$";
+
+
+extern "C" {
+	#include "libmilter/mfapi.h"
+	sfsistat mlfi_connect(SMFICTX *ctx, char *hostname, _SOCK_ADDR *hostaddr);
+	sfsistat mlfi_envfrom(SMFICTX *ctx, char **argv);
+	sfsistat mlfi_envrcpt(SMFICTX *ctx, char **argv);
+	sfsistat mlfi_eom(SMFICTX *ctx);
+	sfsistat mlfi_abort(SMFICTX *ctx);
+	sfsistat mlfi_close(SMFICTX *ctx);
+	void sig_chld(int signo);
+}
+
+int  debug_syslog  = 0;
+bool syslog_opened = false;
+bool use_syslog    = true;	// false to printf
+bool loader_run    = true;	// used to stop the config loader thread
+CONFIG	 *config = NULL;	// protected by the config_mutex
+int   generation = 0;		// protected by the config_mutex
+const int maxlen = 1000;	// used for snprintf buffers
+
+pthread_mutex_t  config_mutex;
+pthread_mutex_t  syslog_mutex;
+
+
+mlfiPriv::mlfiPriv() {
+	pthread_mutex_lock(&config_mutex);
+		pc = config;
+		pc->reference_count++;
+	pthread_mutex_unlock(&config_mutex);
+	mailaddr	   = NULL;
+	queueid 	   = NULL;
+	processed_from = false;
+}
+
+mlfiPriv::~mlfiPriv() {
+	pthread_mutex_lock(&config_mutex);
+		pc->reference_count--;
+	pthread_mutex_unlock(&config_mutex);
+	reset(true);
+}
+
+void mlfiPriv::reset(bool final) {
+	processed_from = false;
+	if (mailaddr) free(mailaddr);
+	if (queueid)  free(queueid);
+	if (!final) {
+		mailaddr = NULL;
+		queueid  = NULL;
+	}
+}
+
+#define MLFIPRIV	((struct mlfiPriv *) smfi_getpriv(ctx))
+
+
+////////////////////////////////////////////////
+// syslog a message
+//
+void my_syslog(mlfiPriv *priv, char *text) {
+	char buf[maxlen];
+	if (priv) {
+		snprintf(buf, sizeof(buf), "%s: %s", priv->queueid, text);
+		text = buf;
+	}
+	if (use_syslog) {
+		pthread_mutex_lock(&syslog_mutex);
+			if (!syslog_opened) {
+				openlog("dnsbl", LOG_PID, LOG_MAIL);
+				syslog_opened = true;
+			}
+			syslog(LOG_NOTICE, "%s", text);
+		pthread_mutex_unlock(&syslog_mutex);
+	}
+	else {
+		printf("%s \n", text);
+	}
+}
+
+void my_syslog(char *text) {
+	my_syslog(NULL, text);
+}
+
+
+////////////////////////////////////////////////
+// this email address is passed in from sendmail, and will
+// always be enclosed in <>. It may have mixed case, just
+// as the mail client sent it. We dup the string and convert
+// the duplicate to lower case.
+//
+char *to_lower_string(char *email);
+char *to_lower_string(char *email) {
+	int n = strlen(email)-2;
+	if (n < 1) return strdup(email);
+	char *key = strdup(email+1);
+	key[n] = '\0';
+	for (int i=0; i<n; i++) key[i] = tolower(key[i]);
+	return key;
+}
+
+
+////////////////////////////////////////////////
+// start of sendmail milter interfaces
+//
+sfsistat mlfi_connect(SMFICTX *ctx, char *hostname, _SOCK_ADDR *hostaddr)
+{
+	// allocate some private memory
+	mlfiPriv *priv = new mlfiPriv;
+	// save the private data
+	smfi_setpriv(ctx, (void*)priv);
+	// continue processing
+	return SMFIS_CONTINUE;
+}
+
+sfsistat mlfi_envfrom(SMFICTX *ctx, char **from)
+{
+	mlfiPriv &priv = *MLFIPRIV;
+	priv.mailaddr  = to_lower_string(from[0]);
+	return SMFIS_CONTINUE;
+}
+
+sfsistat mlfi_envrcpt(SMFICTX *ctx, char **rcpt)
+{
+	mlfiPriv &priv = *MLFIPRIV;
+	CONFIG &dc = *priv.pc;
+	if (!priv.queueid) priv.queueid = strdup(smfi_getsymval(ctx, "i"));
+	char *rcptaddr	= to_lower_string(rcpt[0]);
+	if (debug_syslog > 1) {
+		char msg[maxlen];
+		snprintf(msg, sizeof(msg), "from <%s> to <%s>", priv.mailaddr, rcptaddr);
+		my_syslog(&priv, msg);
+	}
+	char *target = dc.find_to(rcptaddr);
+	if (target) smfi_addrcpt(ctx, target);
+	free(rcptaddr);
+	if (!processed_from) {
+		target = dc.find_from(priv.mailaddr);
+		if (target) smfi_addrcpt(ctx, target);
+		processed_from = true;
+	}
+	return SMFIS_CONTINUE;
+}
+
+sfsistat mlfi_eom(SMFICTX *ctx)
+{
+	// reset for a new message on the same connection
+	mlfi_abort(ctx);
+	return SMFIS_CONTINUE;
+}
+
+sfsistat mlfi_abort(SMFICTX *ctx)
+{
+	mlfiPriv &priv = *MLFIPRIV;
+	if (!priv) return SMFIS_CONTINUE;
+	priv.reset();
+	return SMFIS_CONTINUE;
+}
+
+sfsistat mlfi_close(SMFICTX *ctx)
+{
+	mlfiPriv *priv = MLFIPRIV;
+	if (!priv) return SMFIS_CONTINUE;
+	delete priv;
+	smfi_setpriv(ctx, NULL);
+	return SMFIS_CONTINUE;
+}
+
+struct smfiDesc smfilter =
+{
+	"SM-ARCHIVE",       // filter name
+	SMFI_VERSION,		// version code -- do not change
+	SMFIF_ADDRCPT,		// flags
+	mlfi_connect,		// connection info filter
+	NULL,				// SMTP HELO command filter
+	mlfi_envfrom,		// envelope sender filter
+	mlfi_envrcpt,		// envelope recipient filter
+	NULL,				// header filter
+	NULL,				// end of header
+	NULL,				// body block filter
+	mlfi_eom,			// end of message
+	mlfi_abort, 		// message aborted
+	mlfi_close, 		// connection cleanup
+};
+
+
+////////////////////////////////////////////////
+//	reload the config
+//
+CONFIG* new_conf();
+CONFIG* new_conf() {
+	CONFIG *newc = new CONFIG;
+	pthread_mutex_lock(&config_mutex);
+		newc->generation = generation++;
+	pthread_mutex_unlock(&config_mutex);
+	if (debug_syslog) {
+		char buf[maxlen];
+		snprintf(buf, sizeof(buf), "loading configuration generation %d", newc->generation);
+		my_syslog(buf);
+	}
+	if (load_conf(*newc, "dnsbl.conf")) {
+		newc->load_time = time(NULL);
+		return newc;
+	}
+	delete newc;
+	return NULL;
+}
+
+
+////////////////////////////////////////////////
+//	thread to watch the old config files for changes
+//	and reload when needed. we also cleanup old
+//	configs whose reference count has gone to zero.
+//
+void* config_loader(void *arg);
+void* config_loader(void *arg) {
+	typedef set<CONFIG *> configp_set;
+	configp_set old_configs;
+	while (loader_run) {
+		sleep(180);  // look for modifications every 3 minutes
+		if (!loader_run) break;
+		CONFIG &dc = *config;
+		time_t then = dc.load_time;
+		struct stat st;
+		bool reload = false;
+		for (string_set::iterator i=dc.config_files.begin(); i!=dc.config_files.end(); i++) {
+			char *fn = *i;
+			if (stat(fn, &st))			 reload = true; // file disappeared
+			else if (st.st_mtime > then) reload = true; // file modified
+			if (reload) break;
+		}
+		if (reload) {
+			CONFIG *newc = new_conf();
+			if (newc) {
+				// replace the global config pointer
+				pthread_mutex_lock(&config_mutex);
+					CONFIG *old = config;
+					config = newc;
+				pthread_mutex_unlock(&config_mutex);
+				if (old) old_configs.insert(old);
+			}
+			else {
+				// failed to load new config
+				my_syslog("failed to load new configuration");
+				system("echo 'failed to load new dnsbl configuration from /etc/dnsbl' | mail -s 'error in /etc/dnsbl configuration' root");
+				// update the load time on the current config to prevent complaining every 3 minutes
+				dc.load_time = time(NULL);
+			}
+		}
+		// now look for old configs with zero ref counts
+		for (configp_set::iterator i=old_configs.begin(); i!=old_configs.end(); ) {
+			CONFIG *old = *i;
+			if (!old->reference_count) {
+				if (debug_syslog) {
+					char buf[maxlen];
+					snprintf(buf, sizeof(buf), "freeing memory for old configuration generation %d", old->generation);
+					my_syslog(buf);
+				}
+				delete old; // destructor does all the work
+				old_configs.erase(i++);
+			}
+			else i++;
+		}
+	}
+	return NULL;
+}
+
+
+void usage(char *prog);
+void usage(char *prog)
+{
+	fprintf(stderr, "Usage: %s  [-d [level]] [-c] -p sm-sock-addr [-t timeout]\n", prog);
+	fprintf(stderr, "where sm-sock-addr is for the connection to sendmail\n");
+	fprintf(stderr, "    and should be one of\n");
+	fprintf(stderr, "        inet:port@ip-address\n");
+	fprintf(stderr, "        local:local-domain-socket-file-name\n");
+	fprintf(stderr, "-c will load and dump the config to stdout\n");
+	fprintf(stderr, "-d will set the syslog message level, currently 0 to 3\n");
+}
+
+
+
+void setup_socket(char *sock);
+void setup_socket(char *sock) {
+	unlink(sock);
+	//	sockaddr_un addr;
+	//	memset(&addr, '\0', sizeof addr);
+	//	addr.sun_family = AF_UNIX;
+	//	strncpy(addr.sun_path, sock, sizeof(addr.sun_path)-1);
+	//	int s = socket(AF_UNIX, SOCK_STREAM, 0);
+	//	bind(s, (sockaddr*)&addr, sizeof(addr));
+	//	close(s);
+}
+
+
+/*
+ * The signal handler function -- only gets called when a SIGCHLD
+ * is received, ie when a child terminates
+ */
+void sig_chld(int signo)
+{
+	int status;
+	/* Wait for any child without blocking */
+	while (waitpid(-1, &status, WNOHANG) > 0) {
+		// ignore child exit status, we only do this to cleanup zombies
+	}
+}
+
+
+int main(int argc, char**argv)
+{
+	token_init();
+	bool check	 = false;
+	bool setconn = false;
+	int c;
+	const char *args = "p:t:d:ch";
+	extern char *optarg;
+
+	// Process command line options
+	while ((c = getopt(argc, argv, args)) != -1) {
+		switch (c) {
+			case 'p':
+				if (optarg == NULL || *optarg == '\0') {
+					fprintf(stderr, "Illegal sendmail socket: %s\n", optarg);
+					exit(EX_USAGE);
+				}
+				if (smfi_setconn(optarg) == MI_FAILURE) {
+					fprintf(stderr, "smfi_setconn failed\n");
+					exit(EX_SOFTWARE);
+				}
+					 if (strncasecmp(optarg, "unix:", 5) == 0)  setup_socket(optarg + 5);
+				else if (strncasecmp(optarg, "local:", 6) == 0) setup_socket(optarg + 6);
+				setconn = true;
+				break;
+
+			case 't':
+				if (optarg == NULL || *optarg == '\0') {
+					fprintf(stderr, "Illegal timeout: %s\n", optarg);
+					exit(EX_USAGE);
+				}
+				if (smfi_settimeout(atoi(optarg)) == MI_FAILURE) {
+					fprintf(stderr, "smfi_settimeout failed\n");
+					exit(EX_SOFTWARE);
+				}
+				break;
+
+			case 'c':
+				check = true;
+				break;
+
+			case 'd':
+				if (optarg == NULL || *optarg == '\0') debug_syslog = 1;
+				else								   debug_syslog = atoi(optarg);
+				break;
+
+			case 'h':
+			default:
+				usage(argv[0]);
+				exit(EX_USAGE);
+		}
+	}
+
+	if (check) {
+		use_syslog	 = false;
+		debug_syslog = 10;
+		CONFIG *conf = new_conf();
+		if (conf) {
+			conf->dump();
+			delete conf;
+			return 0;
+		}
+		else {
+			return 1;	// config failed to load
+		}
+	}
+
+	if (!setconn) {
+		fprintf(stderr, "%s: Missing required -p argument\n", argv[0]);
+		usage(argv[0]);
+		exit(EX_USAGE);
+	}
+
+	if (smfi_register(smfilter) == MI_FAILURE) {
+		fprintf(stderr, "smfi_register failed\n");
+		exit(EX_UNAVAILABLE);
+	}
+
+	// switch to background mode
+	if (daemon(1,0) < 0) {
+		fprintf(stderr, "daemon() call failed\n");
+		exit(EX_UNAVAILABLE);
+	}
+
+	// write the pid
+	const char *pidpath = "/var/run/dnsbl.pid";
+	unlink(pidpath);
+	FILE *f = fopen(pidpath, "w");
+	if (f) {
+#ifdef linux
+		// from a comment in the DCC source code:
+		// Linux threads are broken.  Signals given the
+		// original process are delivered to only the
+		// thread that happens to have that PID.  The
+		// sendmail libmilter thread that needs to hear
+		// SIGINT and other signals does not, and that breaks
+		// scripts that need to stop milters.
+		// However, signaling the process group works.
+		fprintf(f, "-%d\n", (u_int)getpgrp());
+#else
+		fprintf(f, "%d\n", (u_int)getpid());
+#endif
+		fclose(f);
+	}
+
+	// initialize the thread sync objects
+	pthread_mutex_init(&config_mutex, 0);
+	pthread_mutex_init(&syslog_mutex, 0);
+
+	// drop root privs
+	struct passwd *pw = getpwnam("sm-archive");
+	if (pw) {
+		if (setgid(pw->pw_gid) == -1) {
+			my_syslog("failed to switch to group dnsbl");
+		}
+		if (setuid(pw->pw_uid) == -1) {
+			my_syslog("failed to switch to user dnsbl");
+		}
+	}
+
+	// load the initial config
+	config = new_conf();
+	if (!config) {
+		my_syslog("failed to load initial configuration, quitting");
+		exit(1);
+	}
+
+	// only create threads after the fork() in daemon
+	pthread_t tid;
+	if (pthread_create(&tid, 0, config_loader, 0))
+		my_syslog("failed to create config loader thread");
+	if (pthread_detach(tid))
+		my_syslog("failed to detach config loader thread");
+
+	time_t starting = time(NULL);
+	int rc = smfi_main();
+	if ((rc != MI_SUCCESS) && (time(NULL) > starting+5*60)) {
+		my_syslog("trying to restart after smfi_main()");
+		loader_run = false; 	// eventually the config loader thread will terminate
+		execvp(argv[0], argv);
+	}
+	exit((rc == MI_SUCCESS) ? 0 : EX_UNAVAILABLE);
+}
+