--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/maildir.c	Thu Mar 27 09:53:52 2014 +0500
@@ -0,0 +1,229 @@
+/*
+ * 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/tree.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+
+#include <fcntl.h>
+#include <dirent.h>
+#include <stdio.h>
+#include <string.h>
+#include <syslog.h>
+#include <unistd.h>
+
+#include "pop3d.h"
+
+static int init(struct mdrop *, size_t *, size_t *);
+static int retr(struct mdrop *, unsigned int, size_t *, size_t *);
+static int update(struct mdrop *);
+static int new_to_cur(struct mdrop *);
+static int msgcmp(struct msg *, struct msg *);
+RB_PROTOTYPE(msgtree, msg, e.t_entry, msgcmp);
+
+struct m_backend m_backend_maildir = {
+	init,
+	retr,
+	update
+};
+
+/*
+ * No resource management on error path as the process is
+ * killed if an error occurs.
+ */
+static int
+init(struct mdrop *m, size_t *nmsgs, size_t *sz)
+{
+	SHA1_CTX	ctx;
+	struct stat	sb;
+	char		buf[MAXBSIZE];
+	DIR		*dirp;
+	struct dirent	*dp;
+	struct msg	*msg;
+	u_char		*C;
+	size_t		i;
+	ssize_t		len;
+	int		cur_fd, msg_fd;
+
+	*nmsgs = 0;
+	*sz = 0;
+	if (new_to_cur(m) == -1) {
+		logit(LOG_WARNING, "maildir: move msgs from new to cur failed");
+		return (-1);
+	}
+
+	if ((cur_fd = openat(m->fd, "cur", O_RDONLY)) == -1) {
+		logit(LOG_CRIT, "maildir: unable to open \"cur\" dir");
+		return (-1);
+	}
+
+	if ((dirp = fdopendir(cur_fd)) == NULL)
+		return (-1);
+
+	while ((dp = readdir(dirp))) {
+		if (dp->d_type != DT_REG)
+			continue;
+
+		if (strcmp(dp->d_name, ".") == 0 ||
+		    strcmp(dp->d_name, "..") == 0)
+			continue;
+
+		msg = xcalloc(1, sizeof(*msg), "init");
+		if ((msg->u.fname = strdup(dp->d_name)) == NULL)
+			fatalx("init: strdup");
+
+		if (fstatat(cur_fd, dp->d_name, &sb, 0) == -1) {
+			logit(LOG_CRIT, "%s fstatat failed", dp->d_name);
+			return (-1);
+		}
+
+		msg->sz = sb.st_size;
+		if ((msg_fd = openat(cur_fd, dp->d_name, O_RDONLY)) == -1) {
+			logit(LOG_CRIT, "%s openat failed", dp->d_name);
+			return (-1);
+		}
+
+		SHA1Init(&ctx);
+		while (( len = read(msg_fd, buf, sizeof(buf))) > 0) {
+			SHA1Update(&ctx, (u_int8_t *)buf, len);
+			for (C = buf;len--; ++C)
+				if (*C == '\n')
+					msg->nlines += 1;
+		}
+
+		SHA1End(&ctx, msg->hash);
+		close(msg_fd);
+		RB_INSERT(msgtree, &m->e.t_msgs, msg);
+		m->nmsgs += 1;
+	}
+
+	/* allocate space for nmsgs of struct msg pointers */
+	m->msgs_index = xcalloc(m->nmsgs, sizeof(msg), "init");
+	*nmsgs = m->nmsgs;
+	i = 0;
+	*sz = 0;
+	RB_FOREACH(msg, msgtree, &m->e.t_msgs) {
+		m->msgs_index[i++] = msg;
+		/* calculate maildir size by counting newline as 2 (CRLF) */
+		*sz += msg->sz + msg->nlines;
+	}
+
+	closedir(dirp);
+	close(cur_fd);
+	return (0);
+}
+
+static int
+new_to_cur(struct mdrop *m)
+{
+	DIR		*dirp;
+	struct dirent	*dp;
+	int		cur_fd, new_fd;
+
+
+	if ((cur_fd = openat(m->fd, "cur", O_RDONLY)) == -1) {
+		logit(LOG_CRIT, "maildir: unable to open \"cur\" dir");
+		return (-1);
+	}
+
+	if ((new_fd = openat(m->fd, "new", O_RDONLY)) == -1) {
+		logit(LOG_CRIT, "maildir: unable to open \"new\" dir");
+		return (-1);
+	}
+
+	if ((dirp = fdopendir(new_fd)) == NULL)
+		return (-1);
+
+	while ((dp = readdir(dirp))) {
+		if (dp->d_type != DT_REG)
+			continue;
+
+		if (strcmp(dp->d_name, ".") == 0 ||
+		    strcmp(dp->d_name, "..") == 0)
+			continue;
+
+		if(renameat(new_fd, dp->d_name, cur_fd, dp->d_name) == -1) {
+			logit(LOG_CRIT, "maildir: renameat failed");
+			return (-1);
+		}
+	}
+
+	closedir(dirp);
+	close(cur_fd);
+	close(new_fd);
+	return (0);
+}
+
+static int
+retr(struct mdrop *m, unsigned int idx, size_t *nlines, size_t *offset)
+{
+	char	buf[MAXPATHLEN];
+	int	fd, r;
+
+	*offset = 0;
+	r = snprintf(buf, sizeof(buf), "cur/%s", m->msgs_index[idx]->u.fname);
+	if ((u_int)r >= sizeof(buf)) {
+		logit(LOG_WARNING, "path too long");
+		return (-1);
+	}
+
+	fd = openat(m->fd, buf, O_RDONLY);
+	return (fd);
+}
+
+static int
+update(struct mdrop *m)
+{
+	char	buf[MAXPATHLEN];
+	size_t	i, j = 0;
+	int	r;
+
+	for (i = 0; i < m->nmsgs; i++)
+		if (m->msgs_index[i]->flags & F_DELE)
+			j += 1;
+
+	if (j == 0) /* nothing to update */
+		return (0);
+
+	for (i = 0; i < m->nmsgs; i++) {
+		if (!(m->msgs_index[i]->flags & F_DELE))
+			continue;
+
+		r = snprintf(buf, sizeof(buf), "cur/%s",
+		    m->msgs_index[i]->u.fname);
+		if ((u_int)r >= sizeof(buf)) {
+			logit(LOG_WARNING, "path too long");
+			return (1);
+		}
+
+		if (unlinkat(m->fd, buf, 0) == -1) {
+			logit(LOG_CRIT, "%s unlink failed", buf);
+			return (1);
+		}
+	}
+
+	return (0);
+}
+
+static int
+msgcmp(struct msg *m1, struct msg *m2)
+{
+	return strcmp(m1->u.fname, m2->u.fname);
+}
+
+RB_GENERATE(msgtree, msg, e.t_entry, msgcmp);