--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/pop3d.c	Thu Mar 27 09:53:52 2014 +0500
@@ -0,0 +1,230 @@
+/*
+ * Copyright (c) 2014 Sunil Nimmagadda <sunil@nimmagadda.net>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/time.h>
+#include <sys/wait.h>
+
+#include <bsd_auth.h>
+#include <err.h>
+#include <event.h>
+#include <login_cap.h>
+#include <pwd.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syslog.h>
+#include <unistd.h>
+
+#include "imsgev.h"
+#include "pop3d.h"
+
+#define	MBOX_PATH	"/var/mail/%u"
+#define MAILDIR_PATH	"~/Maildir"
+#define	POP3D_USER	"_pop3d"
+
+static void authenticate(struct imsgev *, struct imsg *);
+static void pop3e_imsgev(struct imsgev *, int , struct imsg *);
+static void needfd(struct imsgev *);
+static void sig_handler(int, short, void *);
+static enum m_type m_type(const char *);
+static void usage(void);
+
+static struct imsgev	iev_pop3e;
+static pid_t		pop3e_pid;
+static const char	*mpath = MBOX_PATH;
+static int		mtype = M_MBOX;
+
+int
+main(int argc, char *argv[])
+{
+	struct passwd	*pw;
+	struct event	ev_sigint, ev_sigterm, ev_sighup, ev_sigchld;
+	const char	*mtype_str = "mbox";
+	int		ch, d = 0, pair[2];
+
+	while ((ch = getopt(argc, argv, "dp:t:")) != -1) {
+		switch (ch) {
+		case 'd':
+			d = 1;
+			break;
+		case 'p':
+			mpath = optarg;
+			break;
+		case 't':
+			if ((mtype = m_type(optarg)) == -1)
+				errx(1, "%s invalid argument", optarg);
+			if (mtype == M_MAILDIR)
+				mpath = MAILDIR_PATH;
+			mtype_str = optarg;
+			break;
+		default:
+			usage();
+		}
+	}
+
+	argc -= optind;
+	argv += optind;
+	if (argc > 0 || *argv)
+		usage();
+
+	log_init(d);
+	if (geteuid())
+		fatalx("need root privileges");
+
+	if (!d && daemon(1, 0) == -1)
+		fatal("failed to daemonize");
+
+	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) == -1)
+		fatal("socketpair");
+
+	set_nonblocking(pair[0]);
+	set_nonblocking(pair[1]);
+	if ((pw = getpwnam(POP3D_USER)) == NULL)
+		fatalx("main: getpwnam " POP3D_USER);
+
+	pop3e_pid = pop3_main(pair, pw);
+	close(pair[1]);
+	setproctitle("[priv]");
+	logit(LOG_INFO, "pop3d ready; type:%s, path:%s", mtype_str, mpath);
+	event_init();
+	signal_set(&ev_sigint, SIGINT, sig_handler, NULL);
+	signal_set(&ev_sighup, SIGHUP, sig_handler, NULL);
+	signal_set(&ev_sigterm, SIGTERM, sig_handler, NULL);
+	signal_set(&ev_sigchld, SIGCHLD, sig_handler, NULL);
+	signal_add(&ev_sigint, NULL);
+	signal_add(&ev_sighup, NULL);
+	signal_add(&ev_sigterm, NULL);
+	signal_add(&ev_sigchld, NULL);
+	imsgev_init(&iev_pop3e, pair[0], NULL, pop3e_imsgev, needfd);
+	if (event_dispatch() < 0)
+		fatal("event_dispatch");
+
+	logit(LOG_INFO, "pop3d exiting");
+	return (0);
+}
+
+static void
+pop3e_imsgev(struct imsgev *iev, int code, struct imsg *imsg)
+{
+	switch (code) {
+	case IMSGEV_IMSG:
+		switch (imsg->hdr.type) {
+		case IMSG_AUTH:
+			authenticate(iev, imsg);
+			break;
+		default:
+			logit(LOG_DEBUG, "%s: unexpected imsg %u",
+			    __func__, imsg->hdr.type);
+			break;
+		}
+		break;
+	case IMSGEV_EREAD:
+	case IMSGEV_EWRITE:
+	case IMSGEV_EIMSG:
+		fatal("pop3d: imsgev read/write error");
+		break;
+	case IMSGEV_DONE:
+		event_loopexit(NULL);
+		break;
+	}
+}
+
+static void
+authenticate(struct imsgev *iev, struct imsg *imsg)
+{
+	struct auth_req	*req = imsg->data;
+	struct passwd	*pw;
+	int		pair[2];
+
+	if (auth_userokay(req->user, NULL, "auth-pop3", req->pass) == 0) {
+		logit(LOG_INFO, "%u: auth [%s] failed",
+		    imsg->hdr.peerid, req->user);
+		pair[0] = -1;
+		goto end;
+	}
+
+	logit(LOG_INFO, "%u: auth [%s] passed", imsg->hdr.peerid,
+	    req->user);
+	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) == -1)
+		fatal("socketpair");
+
+	set_nonblocking(pair[0]);
+	set_nonblocking(pair[1]);
+	if ((pw = getpwnam(req->user)) == NULL)
+		fatalx("authenticate: getpwnam");
+
+	maildrop_init(imsg->hdr.peerid, pair, pw, mtype, mpath);
+	close(pair[1]);
+
+end:
+	imsgev_xcompose(iev, IMSG_AUTH, imsg->hdr.peerid, 0,
+	    pair[0], NULL, 0, "authenticate");
+}
+
+static void
+needfd(struct imsgev *iev)
+{
+	fatalx("pop3d should never need an fd");
+}
+
+static void
+sig_handler(int sig, short event, void *arg)
+{
+	int status;
+
+	switch (sig) {
+	case SIGINT:
+	case SIGHUP:
+	case SIGTERM:
+		imsgev_clear(&iev_pop3e);
+		imsgev_close(&iev_pop3e);
+		event_loopexit(NULL);
+		break;
+	case SIGCHLD:
+		if (waitpid(pop3e_pid, &status, WNOHANG) > 0)
+			if (WIFEXITED(status) || WIFSIGNALED(status)) {
+				logit(LOG_ERR, "Lost pop3 engine");
+				event_loopexit(NULL);
+			}
+		break;
+	}
+}
+
+static enum m_type
+m_type(const char *str)
+{
+	if (strcasecmp(str, "mbox") == 0)
+		return M_MBOX;
+
+	if (strcasecmp(str, "maildir") == 0)
+		return M_MAILDIR;
+
+	return (-1);
+}
+
+static void
+usage(void)
+{
+	extern char *__progname;
+
+	fprintf(stderr, "usage: %s [-d] [-p path] [-t type]\n", __progname);
+	exit(EXIT_FAILURE);
+}
+