Adding upstream version 1:2.3.19.1+dfsg1.upstream/1%2.3.19.1+dfsg1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

11 files changed, 3100 insertions, 0 deletions

diff --git a/src/lib-storage/index/pop3c/Makefile.am b/src/lib-storage/index/pop3c/Makefile.am
new file mode 100644
index 0000000..868dc1e
--- /dev/null
+++ b/src/lib-storage/index/pop3c/Makefile.am
@@ -0,0 +1,28 @@
+noinst_LTLIBRARIES = libstorage_pop3c.la
+
+AM_CPPFLAGS = \
+	-I$(top_srcdir)/src/lib \
+	-I$(top_srcdir)/src/lib-settings \
+	-I$(top_srcdir)/src/lib-dns \
+	-I$(top_srcdir)/src/lib-ssl-iostream \
+	-I$(top_srcdir)/src/lib-mail \
+	-I$(top_srcdir)/src/lib-imap \
+	-I$(top_srcdir)/src/lib-index \
+	-I$(top_srcdir)/src/lib-storage \
+	-I$(top_srcdir)/src/lib-storage/index
+
+libstorage_pop3c_la_SOURCES = \
+	pop3c-client.c \
+	pop3c-mail.c \
+	pop3c-settings.c \
+	pop3c-storage.c \
+	pop3c-sync.c
+
+headers = \
+	pop3c-client.h \
+	pop3c-settings.h \
+	pop3c-storage.h \
+	pop3c-sync.h
+
+pkginc_libdir=$(pkgincludedir)
+pkginc_lib_HEADERS = $(headers)
diff --git a/src/lib-storage/index/pop3c/Makefile.in b/src/lib-storage/index/pop3c/Makefile.in
new file mode 100644
index 0000000..e66bdcb
--- /dev/null
+++ b/src/lib-storage/index/pop3c/Makefile.in
@@ -0,0 +1,837 @@
+# Makefile.in generated by automake 1.16.1 from Makefile.am.
+# @configure_input@
+
+# Copyright (C) 1994-2018 Free Software Foundation, Inc.
+
+# This Makefile.in is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY, to the extent permitted by law; without
+# even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+# PARTICULAR PURPOSE.
+
+@SET_MAKE@
+
+
+VPATH = @srcdir@
+am__is_gnu_make = { \
+  if test -z '$(MAKELEVEL)'; then \
+    false; \
+  elif test -n '$(MAKE_HOST)'; then \
+    true; \
+  elif test -n '$(MAKE_VERSION)' && test -n '$(CURDIR)'; then \
+    true; \
+  else \
+    false; \
+  fi; \
+}
+am__make_running_with_option = \
+  case $${target_option-} in \
+      ?) ;; \
+      *) echo "am__make_running_with_option: internal error: invalid" \
+              "target option '$${target_option-}' specified" >&2; \
+         exit 1;; \
+  esac; \
+  has_opt=no; \
+  sane_makeflags=$$MAKEFLAGS; \
+  if $(am__is_gnu_make); then \
+    sane_makeflags=$$MFLAGS; \
+  else \
+    case $$MAKEFLAGS in \
+      *\\[\ \	]*) \
+        bs=\\; \
+        sane_makeflags=`printf '%s\n' "$$MAKEFLAGS" \
+          | sed "s/$$bs$$bs[$$bs $$bs	]*//g"`;; \
+    esac; \
+  fi; \
+  skip_next=no; \
+  strip_trailopt () \
+  { \
+    flg=`printf '%s\n' "$$flg" | sed "s/$$1.*$$//"`; \
+  }; \
+  for flg in $$sane_makeflags; do \
+    test $$skip_next = yes && { skip_next=no; continue; }; \
+    case $$flg in \
+      *=*|--*) continue;; \
+        -*I) strip_trailopt 'I'; skip_next=yes;; \
+      -*I?*) strip_trailopt 'I';; \
+        -*O) strip_trailopt 'O'; skip_next=yes;; \
+      -*O?*) strip_trailopt 'O';; \
+        -*l) strip_trailopt 'l'; skip_next=yes;; \
+      -*l?*) strip_trailopt 'l';; \
+      -[dEDm]) skip_next=yes;; \
+      -[JT]) skip_next=yes;; \
+    esac; \
+    case $$flg in \
+      *$$target_option*) has_opt=yes; break;; \
+    esac; \
+  done; \
+  test $$has_opt = yes
+am__make_dryrun = (target_option=n; $(am__make_running_with_option))
+am__make_keepgoing = (target_option=k; $(am__make_running_with_option))
+pkgdatadir = $(datadir)/@PACKAGE@
+pkgincludedir = $(includedir)/@PACKAGE@
+pkglibdir = $(libdir)/@PACKAGE@
+pkglibexecdir = $(libexecdir)/@PACKAGE@
+am__cd = CDPATH="$${ZSH_VERSION+.}$(PATH_SEPARATOR)" && cd
+install_sh_DATA = $(install_sh) -c -m 644
+install_sh_PROGRAM = $(install_sh) -c
+install_sh_SCRIPT = $(install_sh) -c
+INSTALL_HEADER = $(INSTALL_DATA)
+transform = $(program_transform_name)
+NORMAL_INSTALL = :
+PRE_INSTALL = :
+POST_INSTALL = :
+NORMAL_UNINSTALL = :
+PRE_UNINSTALL = :
+POST_UNINSTALL = :
+build_triplet = @build@
+host_triplet = @host@
+subdir = src/lib-storage/index/pop3c
+ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
+am__aclocal_m4_deps = $(top_srcdir)/m4/ac_checktype2.m4 \
+	$(top_srcdir)/m4/ac_typeof.m4 $(top_srcdir)/m4/arc4random.m4 \
+	$(top_srcdir)/m4/blockdev.m4 $(top_srcdir)/m4/c99_vsnprintf.m4 \
+	$(top_srcdir)/m4/clock_gettime.m4 $(top_srcdir)/m4/crypt.m4 \
+	$(top_srcdir)/m4/crypt_xpg6.m4 $(top_srcdir)/m4/dbqlk.m4 \
+	$(top_srcdir)/m4/dirent_dtype.m4 $(top_srcdir)/m4/dovecot.m4 \
+	$(top_srcdir)/m4/fd_passing.m4 $(top_srcdir)/m4/fdatasync.m4 \
+	$(top_srcdir)/m4/flexible_array_member.m4 \
+	$(top_srcdir)/m4/glibc.m4 $(top_srcdir)/m4/gmtime_max.m4 \
+	$(top_srcdir)/m4/gmtime_tm_gmtoff.m4 \
+	$(top_srcdir)/m4/ioloop.m4 $(top_srcdir)/m4/iovec.m4 \
+	$(top_srcdir)/m4/ipv6.m4 $(top_srcdir)/m4/libcap.m4 \
+	$(top_srcdir)/m4/libtool.m4 $(top_srcdir)/m4/libwrap.m4 \
+	$(top_srcdir)/m4/linux_mremap.m4 $(top_srcdir)/m4/ltoptions.m4 \
+	$(top_srcdir)/m4/ltsugar.m4 $(top_srcdir)/m4/ltversion.m4 \
+	$(top_srcdir)/m4/lt~obsolete.m4 $(top_srcdir)/m4/mmap_write.m4 \
+	$(top_srcdir)/m4/mntctl.m4 $(top_srcdir)/m4/modules.m4 \
+	$(top_srcdir)/m4/notify.m4 $(top_srcdir)/m4/nsl.m4 \
+	$(top_srcdir)/m4/off_t_max.m4 $(top_srcdir)/m4/pkg.m4 \
+	$(top_srcdir)/m4/pr_set_dumpable.m4 \
+	$(top_srcdir)/m4/q_quotactl.m4 $(top_srcdir)/m4/quota.m4 \
+	$(top_srcdir)/m4/random.m4 $(top_srcdir)/m4/rlimit.m4 \
+	$(top_srcdir)/m4/sendfile.m4 $(top_srcdir)/m4/size_t_signed.m4 \
+	$(top_srcdir)/m4/sockpeercred.m4 $(top_srcdir)/m4/sql.m4 \
+	$(top_srcdir)/m4/ssl.m4 $(top_srcdir)/m4/st_tim.m4 \
+	$(top_srcdir)/m4/static_array.m4 $(top_srcdir)/m4/test_with.m4 \
+	$(top_srcdir)/m4/time_t.m4 $(top_srcdir)/m4/typeof.m4 \
+	$(top_srcdir)/m4/typeof_dev_t.m4 \
+	$(top_srcdir)/m4/uoff_t_max.m4 $(top_srcdir)/m4/vararg.m4 \
+	$(top_srcdir)/m4/want_apparmor.m4 \
+	$(top_srcdir)/m4/want_bsdauth.m4 \
+	$(top_srcdir)/m4/want_bzlib.m4 \
+	$(top_srcdir)/m4/want_cassandra.m4 \
+	$(top_srcdir)/m4/want_cdb.m4 \
+	$(top_srcdir)/m4/want_checkpassword.m4 \
+	$(top_srcdir)/m4/want_clucene.m4 $(top_srcdir)/m4/want_db.m4 \
+	$(top_srcdir)/m4/want_gssapi.m4 $(top_srcdir)/m4/want_icu.m4 \
+	$(top_srcdir)/m4/want_ldap.m4 $(top_srcdir)/m4/want_lua.m4 \
+	$(top_srcdir)/m4/want_lz4.m4 $(top_srcdir)/m4/want_lzma.m4 \
+	$(top_srcdir)/m4/want_mysql.m4 $(top_srcdir)/m4/want_pam.m4 \
+	$(top_srcdir)/m4/want_passwd.m4 $(top_srcdir)/m4/want_pgsql.m4 \
+	$(top_srcdir)/m4/want_prefetch.m4 \
+	$(top_srcdir)/m4/want_shadow.m4 \
+	$(top_srcdir)/m4/want_sodium.m4 $(top_srcdir)/m4/want_solr.m4 \
+	$(top_srcdir)/m4/want_sqlite.m4 \
+	$(top_srcdir)/m4/want_stemmer.m4 \
+	$(top_srcdir)/m4/want_systemd.m4 \
+	$(top_srcdir)/m4/want_textcat.m4 \
+	$(top_srcdir)/m4/want_unwind.m4 $(top_srcdir)/m4/want_zlib.m4 \
+	$(top_srcdir)/m4/want_zstd.m4 $(top_srcdir)/configure.ac
+am__configure_deps = $(am__aclocal_m4_deps) $(CONFIGURE_DEPENDENCIES) \
+	$(ACLOCAL_M4)
+DIST_COMMON = $(srcdir)/Makefile.am $(pkginc_lib_HEADERS) \
+	$(am__DIST_COMMON)
+mkinstalldirs = $(install_sh) -d
+CONFIG_HEADER = $(top_builddir)/config.h
+CONFIG_CLEAN_FILES =
+CONFIG_CLEAN_VPATH_FILES =
+LTLIBRARIES = $(noinst_LTLIBRARIES)
+libstorage_pop3c_la_LIBADD =
+am_libstorage_pop3c_la_OBJECTS = pop3c-client.lo pop3c-mail.lo \
+	pop3c-settings.lo pop3c-storage.lo pop3c-sync.lo
+libstorage_pop3c_la_OBJECTS = $(am_libstorage_pop3c_la_OBJECTS)
+AM_V_lt = $(am__v_lt_@AM_V@)
+am__v_lt_ = $(am__v_lt_@AM_DEFAULT_V@)
+am__v_lt_0 = --silent
+am__v_lt_1 = 
+AM_V_P = $(am__v_P_@AM_V@)
+am__v_P_ = $(am__v_P_@AM_DEFAULT_V@)
+am__v_P_0 = false
+am__v_P_1 = :
+AM_V_GEN = $(am__v_GEN_@AM_V@)
+am__v_GEN_ = $(am__v_GEN_@AM_DEFAULT_V@)
+am__v_GEN_0 = @echo "  GEN     " $@;
+am__v_GEN_1 = 
+AM_V_at = $(am__v_at_@AM_V@)
+am__v_at_ = $(am__v_at_@AM_DEFAULT_V@)
+am__v_at_0 = @
+am__v_at_1 = 
+DEFAULT_INCLUDES = -I.@am__isrc@ -I$(top_builddir)
+depcomp = $(SHELL) $(top_srcdir)/depcomp
+am__maybe_remake_depfiles = depfiles
+am__depfiles_remade = ./$(DEPDIR)/pop3c-client.Plo \
+	./$(DEPDIR)/pop3c-mail.Plo ./$(DEPDIR)/pop3c-settings.Plo \
+	./$(DEPDIR)/pop3c-storage.Plo ./$(DEPDIR)/pop3c-sync.Plo
+am__mv = mv -f
+COMPILE = $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) \
+	$(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS)
+LTCOMPILE = $(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) \
+	$(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) \
+	$(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) \
+	$(AM_CFLAGS) $(CFLAGS)
+AM_V_CC = $(am__v_CC_@AM_V@)
+am__v_CC_ = $(am__v_CC_@AM_DEFAULT_V@)
+am__v_CC_0 = @echo "  CC      " $@;
+am__v_CC_1 = 
+CCLD = $(CC)
+LINK = $(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) \
+	$(LIBTOOLFLAGS) --mode=link $(CCLD) $(AM_CFLAGS) $(CFLAGS) \
+	$(AM_LDFLAGS) $(LDFLAGS) -o $@
+AM_V_CCLD = $(am__v_CCLD_@AM_V@)
+am__v_CCLD_ = $(am__v_CCLD_@AM_DEFAULT_V@)
+am__v_CCLD_0 = @echo "  CCLD    " $@;
+am__v_CCLD_1 = 
+SOURCES = $(libstorage_pop3c_la_SOURCES)
+DIST_SOURCES = $(libstorage_pop3c_la_SOURCES)
+am__can_run_installinfo = \
+  case $$AM_UPDATE_INFO_DIR in \
+    n|no|NO) false;; \
+    *) (install-info --version) >/dev/null 2>&1;; \
+  esac
+am__vpath_adj_setup = srcdirstrip=`echo "$(srcdir)" | sed 's|.|.|g'`;
+am__vpath_adj = case $$p in \
+    $(srcdir)/*) f=`echo "$$p" | sed "s|^$$srcdirstrip/||"`;; \
+    *) f=$$p;; \
+  esac;
+am__strip_dir = f=`echo $$p | sed -e 's|^.*/||'`;
+am__install_max = 40
+am__nobase_strip_setup = \
+  srcdirstrip=`echo "$(srcdir)" | sed 's/[].[^$$\\*|]/\\\\&/g'`
+am__nobase_strip = \
+  for p in $$list; do echo "$$p"; done | sed -e "s|$$srcdirstrip/||"
+am__nobase_list = $(am__nobase_strip_setup); \
+  for p in $$list; do echo "$$p $$p"; done | \
+  sed "s| $$srcdirstrip/| |;"' / .*\//!s/ .*/ ./; s,\( .*\)/[^/]*$$,\1,' | \
+  $(AWK) 'BEGIN { files["."] = "" } { files[$$2] = files[$$2] " " $$1; \
+    if (++n[$$2] == $(am__install_max)) \
+      { print $$2, files[$$2]; n[$$2] = 0; files[$$2] = "" } } \
+    END { for (dir in files) print dir, files[dir] }'
+am__base_list = \
+  sed '$$!N;$$!N;$$!N;$$!N;$$!N;$$!N;$$!N;s/\n/ /g' | \
+  sed '$$!N;$$!N;$$!N;$$!N;s/\n/ /g'
+am__uninstall_files_from_dir = { \
+  test -z "$$files" \
+    || { test ! -d "$$dir" && test ! -f "$$dir" && test ! -r "$$dir"; } \
+    || { echo " ( cd '$$dir' && rm -f" $$files ")"; \
+         $(am__cd) "$$dir" && rm -f $$files; }; \
+  }
+am__installdirs = "$(DESTDIR)$(pkginc_libdir)"
+HEADERS = $(pkginc_lib_HEADERS)
+am__tagged_files = $(HEADERS) $(SOURCES) $(TAGS_FILES) $(LISP)
+# Read a list of newline-separated strings from the standard input,
+# and print each of them once, without duplicates.  Input order is
+# *not* preserved.
+am__uniquify_input = $(AWK) '\
+  BEGIN { nonempty = 0; } \
+  { items[$$0] = 1; nonempty = 1; } \
+  END { if (nonempty) { for (i in items) print i; }; } \
+'
+# Make sure the list of sources is unique.  This is necessary because,
+# e.g., the same source file might be shared among _SOURCES variables
+# for different programs/libraries.
+am__define_uniq_tagged_files = \
+  list='$(am__tagged_files)'; \
+  unique=`for i in $$list; do \
+    if test -f "$$i"; then echo $$i; else echo $(srcdir)/$$i; fi; \
+  done | $(am__uniquify_input)`
+ETAGS = etags
+CTAGS = ctags
+am__DIST_COMMON = $(srcdir)/Makefile.in $(top_srcdir)/depcomp
+DISTFILES = $(DIST_COMMON) $(DIST_SOURCES) $(TEXINFOS) $(EXTRA_DIST)
+ACLOCAL = @ACLOCAL@
+ACLOCAL_AMFLAGS = @ACLOCAL_AMFLAGS@
+AMTAR = @AMTAR@
+AM_DEFAULT_VERBOSITY = @AM_DEFAULT_VERBOSITY@
+APPARMOR_LIBS = @APPARMOR_LIBS@
+AR = @AR@
+AUTH_CFLAGS = @AUTH_CFLAGS@
+AUTH_LIBS = @AUTH_LIBS@
+AUTOCONF = @AUTOCONF@
+AUTOHEADER = @AUTOHEADER@
+AUTOMAKE = @AUTOMAKE@
+AWK = @AWK@
+BINARY_CFLAGS = @BINARY_CFLAGS@
+BINARY_LDFLAGS = @BINARY_LDFLAGS@
+BISON = @BISON@
+CASSANDRA_CFLAGS = @CASSANDRA_CFLAGS@
+CASSANDRA_LIBS = @CASSANDRA_LIBS@
+CC = @CC@
+CCDEPMODE = @CCDEPMODE@
+CDB_LIBS = @CDB_LIBS@
+CFLAGS = @CFLAGS@
+CLUCENE_CFLAGS = @CLUCENE_CFLAGS@
+CLUCENE_LIBS = @CLUCENE_LIBS@
+COMPRESS_LIBS = @COMPRESS_LIBS@
+CPP = @CPP@
+CPPFLAGS = @CPPFLAGS@
+CRYPT_LIBS = @CRYPT_LIBS@
+CXX = @CXX@
+CXXCPP = @CXXCPP@
+CXXDEPMODE = @CXXDEPMODE@
+CXXFLAGS = @CXXFLAGS@
+CYGPATH_W = @CYGPATH_W@
+DEFS = @DEFS@
+DEPDIR = @DEPDIR@
+DICT_LIBS = @DICT_LIBS@
+DLLIB = @DLLIB@
+DLLTOOL = @DLLTOOL@
+DSYMUTIL = @DSYMUTIL@
+DUMPBIN = @DUMPBIN@
+ECHO_C = @ECHO_C@
+ECHO_N = @ECHO_N@
+ECHO_T = @ECHO_T@
+EGREP = @EGREP@
+EXEEXT = @EXEEXT@
+FGREP = @FGREP@
+FLEX = @FLEX@
+FUZZER_CPPFLAGS = @FUZZER_CPPFLAGS@
+FUZZER_LDFLAGS = @FUZZER_LDFLAGS@
+GREP = @GREP@
+INSTALL = @INSTALL@
+INSTALL_DATA = @INSTALL_DATA@
+INSTALL_PROGRAM = @INSTALL_PROGRAM@
+INSTALL_SCRIPT = @INSTALL_SCRIPT@
+INSTALL_STRIP_PROGRAM = @INSTALL_STRIP_PROGRAM@
+KRB5CONFIG = @KRB5CONFIG@
+KRB5_CFLAGS = @KRB5_CFLAGS@
+KRB5_LIBS = @KRB5_LIBS@
+LD = @LD@
+LDAP_LIBS = @LDAP_LIBS@
+LDFLAGS = @LDFLAGS@
+LD_NO_WHOLE_ARCHIVE = @LD_NO_WHOLE_ARCHIVE@
+LD_WHOLE_ARCHIVE = @LD_WHOLE_ARCHIVE@
+LIBCAP = @LIBCAP@
+LIBDOVECOT = @LIBDOVECOT@
+LIBDOVECOT_COMPRESS = @LIBDOVECOT_COMPRESS@
+LIBDOVECOT_DEPS = @LIBDOVECOT_DEPS@
+LIBDOVECOT_DSYNC = @LIBDOVECOT_DSYNC@
+LIBDOVECOT_LA_LIBS = @LIBDOVECOT_LA_LIBS@
+LIBDOVECOT_LDA = @LIBDOVECOT_LDA@
+LIBDOVECOT_LDAP = @LIBDOVECOT_LDAP@
+LIBDOVECOT_LIBFTS = @LIBDOVECOT_LIBFTS@
+LIBDOVECOT_LIBFTS_DEPS = @LIBDOVECOT_LIBFTS_DEPS@
+LIBDOVECOT_LOGIN = @LIBDOVECOT_LOGIN@
+LIBDOVECOT_LUA = @LIBDOVECOT_LUA@
+LIBDOVECOT_LUA_DEPS = @LIBDOVECOT_LUA_DEPS@
+LIBDOVECOT_SQL = @LIBDOVECOT_SQL@
+LIBDOVECOT_STORAGE = @LIBDOVECOT_STORAGE@
+LIBDOVECOT_STORAGE_DEPS = @LIBDOVECOT_STORAGE_DEPS@
+LIBEXTTEXTCAT_CFLAGS = @LIBEXTTEXTCAT_CFLAGS@
+LIBEXTTEXTCAT_LIBS = @LIBEXTTEXTCAT_LIBS@
+LIBICONV = @LIBICONV@
+LIBICU_CFLAGS = @LIBICU_CFLAGS@
+LIBICU_LIBS = @LIBICU_LIBS@
+LIBOBJS = @LIBOBJS@
+LIBS = @LIBS@
+LIBSODIUM_CFLAGS = @LIBSODIUM_CFLAGS@
+LIBSODIUM_LIBS = @LIBSODIUM_LIBS@
+LIBTIRPC_CFLAGS = @LIBTIRPC_CFLAGS@
+LIBTIRPC_LIBS = @LIBTIRPC_LIBS@
+LIBTOOL = @LIBTOOL@
+LIBUNWIND_CFLAGS = @LIBUNWIND_CFLAGS@
+LIBUNWIND_LIBS = @LIBUNWIND_LIBS@
+LIBWRAP_LIBS = @LIBWRAP_LIBS@
+LINKED_STORAGE_LDADD = @LINKED_STORAGE_LDADD@
+LIPO = @LIPO@
+LN_S = @LN_S@
+LTLIBICONV = @LTLIBICONV@
+LTLIBOBJS = @LTLIBOBJS@
+LT_SYS_LIBRARY_PATH = @LT_SYS_LIBRARY_PATH@
+LUA_CFLAGS = @LUA_CFLAGS@
+LUA_LIBS = @LUA_LIBS@
+MAINT = @MAINT@
+MAKEINFO = @MAKEINFO@
+MANIFEST_TOOL = @MANIFEST_TOOL@
+MKDIR_P = @MKDIR_P@
+MODULE_LIBS = @MODULE_LIBS@
+MODULE_SUFFIX = @MODULE_SUFFIX@
+MYSQL_CFLAGS = @MYSQL_CFLAGS@
+MYSQL_CONFIG = @MYSQL_CONFIG@
+MYSQL_LIBS = @MYSQL_LIBS@
+NM = @NM@
+NMEDIT = @NMEDIT@
+NOPLUGIN_LDFLAGS = @NOPLUGIN_LDFLAGS@
+OBJDUMP = @OBJDUMP@
+OBJEXT = @OBJEXT@
+OTOOL = @OTOOL@
+OTOOL64 = @OTOOL64@
+PACKAGE = @PACKAGE@
+PACKAGE_BUGREPORT = @PACKAGE_BUGREPORT@
+PACKAGE_NAME = @PACKAGE_NAME@
+PACKAGE_STRING = @PACKAGE_STRING@
+PACKAGE_TARNAME = @PACKAGE_TARNAME@
+PACKAGE_URL = @PACKAGE_URL@
+PACKAGE_VERSION = @PACKAGE_VERSION@
+PANDOC = @PANDOC@
+PATH_SEPARATOR = @PATH_SEPARATOR@
+PGSQL_CFLAGS = @PGSQL_CFLAGS@
+PGSQL_LIBS = @PGSQL_LIBS@
+PG_CONFIG = @PG_CONFIG@
+PIE_CFLAGS = @PIE_CFLAGS@
+PIE_LDFLAGS = @PIE_LDFLAGS@
+PKG_CONFIG = @PKG_CONFIG@
+PKG_CONFIG_LIBDIR = @PKG_CONFIG_LIBDIR@
+PKG_CONFIG_PATH = @PKG_CONFIG_PATH@
+QUOTA_LIBS = @QUOTA_LIBS@
+RANLIB = @RANLIB@
+RELRO_LDFLAGS = @RELRO_LDFLAGS@
+RPCGEN = @RPCGEN@
+RUN_TEST = @RUN_TEST@
+SED = @SED@
+SETTING_FILES = @SETTING_FILES@
+SET_MAKE = @SET_MAKE@
+SHELL = @SHELL@
+SQLITE_CFLAGS = @SQLITE_CFLAGS@
+SQLITE_LIBS = @SQLITE_LIBS@
+SQL_CFLAGS = @SQL_CFLAGS@
+SQL_LIBS = @SQL_LIBS@
+SSL_CFLAGS = @SSL_CFLAGS@
+SSL_LIBS = @SSL_LIBS@
+STRIP = @STRIP@
+SYSTEMD_CFLAGS = @SYSTEMD_CFLAGS@
+SYSTEMD_LIBS = @SYSTEMD_LIBS@
+VALGRIND = @VALGRIND@
+VERSION = @VERSION@
+ZSTD_CFLAGS = @ZSTD_CFLAGS@
+ZSTD_LIBS = @ZSTD_LIBS@
+abs_builddir = @abs_builddir@
+abs_srcdir = @abs_srcdir@
+abs_top_builddir = @abs_top_builddir@
+abs_top_srcdir = @abs_top_srcdir@
+ac_ct_AR = @ac_ct_AR@
+ac_ct_CC = @ac_ct_CC@
+ac_ct_CXX = @ac_ct_CXX@
+ac_ct_DUMPBIN = @ac_ct_DUMPBIN@
+am__include = @am__include@
+am__leading_dot = @am__leading_dot@
+am__quote = @am__quote@
+am__tar = @am__tar@
+am__untar = @am__untar@
+bindir = @bindir@
+build = @build@
+build_alias = @build_alias@
+build_cpu = @build_cpu@
+build_os = @build_os@
+build_vendor = @build_vendor@
+builddir = @builddir@
+datadir = @datadir@
+datarootdir = @datarootdir@
+dict_drivers = @dict_drivers@
+docdir = @docdir@
+dvidir = @dvidir@
+exec_prefix = @exec_prefix@
+host = @host@
+host_alias = @host_alias@
+host_cpu = @host_cpu@
+host_os = @host_os@
+host_vendor = @host_vendor@
+htmldir = @htmldir@
+includedir = @includedir@
+infodir = @infodir@
+install_sh = @install_sh@
+libdir = @libdir@
+libexecdir = @libexecdir@
+localedir = @localedir@
+localstatedir = @localstatedir@
+mandir = @mandir@
+mkdir_p = @mkdir_p@
+moduledir = @moduledir@
+oldincludedir = @oldincludedir@
+pdfdir = @pdfdir@
+prefix = @prefix@
+program_transform_name = @program_transform_name@
+psdir = @psdir@
+rundir = @rundir@
+runstatedir = @runstatedir@
+sbindir = @sbindir@
+sharedstatedir = @sharedstatedir@
+sql_drivers = @sql_drivers@
+srcdir = @srcdir@
+ssldir = @ssldir@
+statedir = @statedir@
+sysconfdir = @sysconfdir@
+systemdservicetype = @systemdservicetype@
+systemdsystemunitdir = @systemdsystemunitdir@
+target_alias = @target_alias@
+top_build_prefix = @top_build_prefix@
+top_builddir = @top_builddir@
+top_srcdir = @top_srcdir@
+noinst_LTLIBRARIES = libstorage_pop3c.la
+AM_CPPFLAGS = \
+	-I$(top_srcdir)/src/lib \
+	-I$(top_srcdir)/src/lib-settings \
+	-I$(top_srcdir)/src/lib-dns \
+	-I$(top_srcdir)/src/lib-ssl-iostream \
+	-I$(top_srcdir)/src/lib-mail \
+	-I$(top_srcdir)/src/lib-imap \
+	-I$(top_srcdir)/src/lib-index \
+	-I$(top_srcdir)/src/lib-storage \
+	-I$(top_srcdir)/src/lib-storage/index
+
+libstorage_pop3c_la_SOURCES = \
+	pop3c-client.c \
+	pop3c-mail.c \
+	pop3c-settings.c \
+	pop3c-storage.c \
+	pop3c-sync.c
+
+headers = \
+	pop3c-client.h \
+	pop3c-settings.h \
+	pop3c-storage.h \
+	pop3c-sync.h
+
+pkginc_libdir = $(pkgincludedir)
+pkginc_lib_HEADERS = $(headers)
+all: all-am
+
+.SUFFIXES:
+.SUFFIXES: .c .lo .o .obj
+$(srcdir)/Makefile.in: @MAINTAINER_MODE_TRUE@ $(srcdir)/Makefile.am  $(am__configure_deps)
+	@for dep in $?; do \
+	  case '$(am__configure_deps)' in \
+	    *$$dep*) \
+	      ( cd $(top_builddir) && $(MAKE) $(AM_MAKEFLAGS) am--refresh ) \
+	        && { if test -f $@; then exit 0; else break; fi; }; \
+	      exit 1;; \
+	  esac; \
+	done; \
+	echo ' cd $(top_srcdir) && $(AUTOMAKE) --foreign src/lib-storage/index/pop3c/Makefile'; \
+	$(am__cd) $(top_srcdir) && \
+	  $(AUTOMAKE) --foreign src/lib-storage/index/pop3c/Makefile
+Makefile: $(srcdir)/Makefile.in $(top_builddir)/config.status
+	@case '$?' in \
+	  *config.status*) \
+	    cd $(top_builddir) && $(MAKE) $(AM_MAKEFLAGS) am--refresh;; \
+	  *) \
+	    echo ' cd $(top_builddir) && $(SHELL) ./config.status $(subdir)/$@ $(am__maybe_remake_depfiles)'; \
+	    cd $(top_builddir) && $(SHELL) ./config.status $(subdir)/$@ $(am__maybe_remake_depfiles);; \
+	esac;
+
+$(top_builddir)/config.status: $(top_srcdir)/configure $(CONFIG_STATUS_DEPENDENCIES)
+	cd $(top_builddir) && $(MAKE) $(AM_MAKEFLAGS) am--refresh
+
+$(top_srcdir)/configure: @MAINTAINER_MODE_TRUE@ $(am__configure_deps)
+	cd $(top_builddir) && $(MAKE) $(AM_MAKEFLAGS) am--refresh
+$(ACLOCAL_M4): @MAINTAINER_MODE_TRUE@ $(am__aclocal_m4_deps)
+	cd $(top_builddir) && $(MAKE) $(AM_MAKEFLAGS) am--refresh
+$(am__aclocal_m4_deps):
+
+clean-noinstLTLIBRARIES:
+	-test -z "$(noinst_LTLIBRARIES)" || rm -f $(noinst_LTLIBRARIES)
+	@list='$(noinst_LTLIBRARIES)'; \
+	locs=`for p in $$list; do echo $$p; done | \
+	      sed 's|^[^/]*$$|.|; s|/[^/]*$$||; s|$$|/so_locations|' | \
+	      sort -u`; \
+	test -z "$$locs" || { \
+	  echo rm -f $${locs}; \
+	  rm -f $${locs}; \
+	}
+
+libstorage_pop3c.la: $(libstorage_pop3c_la_OBJECTS) $(libstorage_pop3c_la_DEPENDENCIES) $(EXTRA_libstorage_pop3c_la_DEPENDENCIES) 
+	$(AM_V_CCLD)$(LINK)  $(libstorage_pop3c_la_OBJECTS) $(libstorage_pop3c_la_LIBADD) $(LIBS)
+
+mostlyclean-compile:
+	-rm -f *.$(OBJEXT)
+
+distclean-compile:
+	-rm -f *.tab.c
+
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pop3c-client.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pop3c-mail.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pop3c-settings.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pop3c-storage.Plo@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pop3c-sync.Plo@am__quote@ # am--include-marker
+
+$(am__depfiles_remade):
+	@$(MKDIR_P) $(@D)
+	@echo '# dummy' >$@-t && $(am__mv) $@-t $@
+
+am--depfiles: $(am__depfiles_remade)
+
+.c.o:
+@am__fastdepCC_TRUE@	$(AM_V_CC)$(COMPILE) -MT $@ -MD -MP -MF $(DEPDIR)/$*.Tpo -c -o $@ $<
+@am__fastdepCC_TRUE@	$(AM_V_at)$(am__mv) $(DEPDIR)/$*.Tpo $(DEPDIR)/$*.Po
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	$(AM_V_CC)source='$<' object='$@' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(COMPILE) -c -o $@ $<
+
+.c.obj:
+@am__fastdepCC_TRUE@	$(AM_V_CC)$(COMPILE) -MT $@ -MD -MP -MF $(DEPDIR)/$*.Tpo -c -o $@ `$(CYGPATH_W) '$<'`
+@am__fastdepCC_TRUE@	$(AM_V_at)$(am__mv) $(DEPDIR)/$*.Tpo $(DEPDIR)/$*.Po
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	$(AM_V_CC)source='$<' object='$@' libtool=no @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(COMPILE) -c -o $@ `$(CYGPATH_W) '$<'`
+
+.c.lo:
+@am__fastdepCC_TRUE@	$(AM_V_CC)$(LTCOMPILE) -MT $@ -MD -MP -MF $(DEPDIR)/$*.Tpo -c -o $@ $<
+@am__fastdepCC_TRUE@	$(AM_V_at)$(am__mv) $(DEPDIR)/$*.Tpo $(DEPDIR)/$*.Plo
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	$(AM_V_CC)source='$<' object='$@' libtool=yes @AMDEPBACKSLASH@
+@AMDEP_TRUE@@am__fastdepCC_FALSE@	DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@
+@am__fastdepCC_FALSE@	$(AM_V_CC@am__nodep@)$(LTCOMPILE) -c -o $@ $<
+
+mostlyclean-libtool:
+	-rm -f *.lo
+
+clean-libtool:
+	-rm -rf .libs _libs
+install-pkginc_libHEADERS: $(pkginc_lib_HEADERS)
+	@$(NORMAL_INSTALL)
+	@list='$(pkginc_lib_HEADERS)'; test -n "$(pkginc_libdir)" || list=; \
+	if test -n "$$list"; then \
+	  echo " $(MKDIR_P) '$(DESTDIR)$(pkginc_libdir)'"; \
+	  $(MKDIR_P) "$(DESTDIR)$(pkginc_libdir)" || exit 1; \
+	fi; \
+	for p in $$list; do \
+	  if test -f "$$p"; then d=; else d="$(srcdir)/"; fi; \
+	  echo "$$d$$p"; \
+	done | $(am__base_list) | \
+	while read files; do \
+	  echo " $(INSTALL_HEADER) $$files '$(DESTDIR)$(pkginc_libdir)'"; \
+	  $(INSTALL_HEADER) $$files "$(DESTDIR)$(pkginc_libdir)" || exit $$?; \
+	done
+
+uninstall-pkginc_libHEADERS:
+	@$(NORMAL_UNINSTALL)
+	@list='$(pkginc_lib_HEADERS)'; test -n "$(pkginc_libdir)" || list=; \
+	files=`for p in $$list; do echo $$p; done | sed -e 's|^.*/||'`; \
+	dir='$(DESTDIR)$(pkginc_libdir)'; $(am__uninstall_files_from_dir)
+
+ID: $(am__tagged_files)
+	$(am__define_uniq_tagged_files); mkid -fID $$unique
+tags: tags-am
+TAGS: tags
+
+tags-am: $(TAGS_DEPENDENCIES) $(am__tagged_files)
+	set x; \
+	here=`pwd`; \
+	$(am__define_uniq_tagged_files); \
+	shift; \
+	if test -z "$(ETAGS_ARGS)$$*$$unique"; then :; else \
+	  test -n "$$unique" || unique=$$empty_fix; \
+	  if test $$# -gt 0; then \
+	    $(ETAGS) $(ETAGSFLAGS) $(AM_ETAGSFLAGS) $(ETAGS_ARGS) \
+	      "$$@" $$unique; \
+	  else \
+	    $(ETAGS) $(ETAGSFLAGS) $(AM_ETAGSFLAGS) $(ETAGS_ARGS) \
+	      $$unique; \
+	  fi; \
+	fi
+ctags: ctags-am
+
+CTAGS: ctags
+ctags-am: $(TAGS_DEPENDENCIES) $(am__tagged_files)
+	$(am__define_uniq_tagged_files); \
+	test -z "$(CTAGS_ARGS)$$unique" \
+	  || $(CTAGS) $(CTAGSFLAGS) $(AM_CTAGSFLAGS) $(CTAGS_ARGS) \
+	     $$unique
+
+GTAGS:
+	here=`$(am__cd) $(top_builddir) && pwd` \
+	  && $(am__cd) $(top_srcdir) \
+	  && gtags -i $(GTAGS_ARGS) "$$here"
+cscopelist: cscopelist-am
+
+cscopelist-am: $(am__tagged_files)
+	list='$(am__tagged_files)'; \
+	case "$(srcdir)" in \
+	  [\\/]* | ?:[\\/]*) sdir="$(srcdir)" ;; \
+	  *) sdir=$(subdir)/$(srcdir) ;; \
+	esac; \
+	for i in $$list; do \
+	  if test -f "$$i"; then \
+	    echo "$(subdir)/$$i"; \
+	  else \
+	    echo "$$sdir/$$i"; \
+	  fi; \
+	done >> $(top_builddir)/cscope.files
+
+distclean-tags:
+	-rm -f TAGS ID GTAGS GRTAGS GSYMS GPATH tags
+
+distdir: $(BUILT_SOURCES)
+	$(MAKE) $(AM_MAKEFLAGS) distdir-am
+
+distdir-am: $(DISTFILES)
+	@srcdirstrip=`echo "$(srcdir)" | sed 's/[].[^$$\\*]/\\\\&/g'`; \
+	topsrcdirstrip=`echo "$(top_srcdir)" | sed 's/[].[^$$\\*]/\\\\&/g'`; \
+	list='$(DISTFILES)'; \
+	  dist_files=`for file in $$list; do echo $$file; done | \
+	  sed -e "s|^$$srcdirstrip/||;t" \
+	      -e "s|^$$topsrcdirstrip/|$(top_builddir)/|;t"`; \
+	case $$dist_files in \
+	  */*) $(MKDIR_P) `echo "$$dist_files" | \
+			   sed '/\//!d;s|^|$(distdir)/|;s,/[^/]*$$,,' | \
+			   sort -u` ;; \
+	esac; \
+	for file in $$dist_files; do \
+	  if test -f $$file || test -d $$file; then d=.; else d=$(srcdir); fi; \
+	  if test -d $$d/$$file; then \
+	    dir=`echo "/$$file" | sed -e 's,/[^/]*$$,,'`; \
+	    if test -d "$(distdir)/$$file"; then \
+	      find "$(distdir)/$$file" -type d ! -perm -700 -exec chmod u+rwx {} \;; \
+	    fi; \
+	    if test -d $(srcdir)/$$file && test $$d != $(srcdir); then \
+	      cp -fpR $(srcdir)/$$file "$(distdir)$$dir" || exit 1; \
+	      find "$(distdir)/$$file" -type d ! -perm -700 -exec chmod u+rwx {} \;; \
+	    fi; \
+	    cp -fpR $$d/$$file "$(distdir)$$dir" || exit 1; \
+	  else \
+	    test -f "$(distdir)/$$file" \
+	    || cp -p $$d/$$file "$(distdir)/$$file" \
+	    || exit 1; \
+	  fi; \
+	done
+check-am: all-am
+check: check-am
+all-am: Makefile $(LTLIBRARIES) $(HEADERS)
+installdirs:
+	for dir in "$(DESTDIR)$(pkginc_libdir)"; do \
+	  test -z "$$dir" || $(MKDIR_P) "$$dir"; \
+	done
+install: install-am
+install-exec: install-exec-am
+install-data: install-data-am
+uninstall: uninstall-am
+
+install-am: all-am
+	@$(MAKE) $(AM_MAKEFLAGS) install-exec-am install-data-am
+
+installcheck: installcheck-am
+install-strip:
+	if test -z '$(STRIP)'; then \
+	  $(MAKE) $(AM_MAKEFLAGS) INSTALL_PROGRAM="$(INSTALL_STRIP_PROGRAM)" \
+	    install_sh_PROGRAM="$(INSTALL_STRIP_PROGRAM)" INSTALL_STRIP_FLAG=-s \
+	      install; \
+	else \
+	  $(MAKE) $(AM_MAKEFLAGS) INSTALL_PROGRAM="$(INSTALL_STRIP_PROGRAM)" \
+	    install_sh_PROGRAM="$(INSTALL_STRIP_PROGRAM)" INSTALL_STRIP_FLAG=-s \
+	    "INSTALL_PROGRAM_ENV=STRIPPROG='$(STRIP)'" install; \
+	fi
+mostlyclean-generic:
+
+clean-generic:
+
+distclean-generic:
+	-test -z "$(CONFIG_CLEAN_FILES)" || rm -f $(CONFIG_CLEAN_FILES)
+	-test . = "$(srcdir)" || test -z "$(CONFIG_CLEAN_VPATH_FILES)" || rm -f $(CONFIG_CLEAN_VPATH_FILES)
+
+maintainer-clean-generic:
+	@echo "This command is intended for maintainers to use"
+	@echo "it deletes files that may require special tools to rebuild."
+clean: clean-am
+
+clean-am: clean-generic clean-libtool clean-noinstLTLIBRARIES \
+	mostlyclean-am
+
+distclean: distclean-am
+		-rm -f ./$(DEPDIR)/pop3c-client.Plo
+	-rm -f ./$(DEPDIR)/pop3c-mail.Plo
+	-rm -f ./$(DEPDIR)/pop3c-settings.Plo
+	-rm -f ./$(DEPDIR)/pop3c-storage.Plo
+	-rm -f ./$(DEPDIR)/pop3c-sync.Plo
+	-rm -f Makefile
+distclean-am: clean-am distclean-compile distclean-generic \
+	distclean-tags
+
+dvi: dvi-am
+
+dvi-am:
+
+html: html-am
+
+html-am:
+
+info: info-am
+
+info-am:
+
+install-data-am: install-pkginc_libHEADERS
+
+install-dvi: install-dvi-am
+
+install-dvi-am:
+
+install-exec-am:
+
+install-html: install-html-am
+
+install-html-am:
+
+install-info: install-info-am
+
+install-info-am:
+
+install-man:
+
+install-pdf: install-pdf-am
+
+install-pdf-am:
+
+install-ps: install-ps-am
+
+install-ps-am:
+
+installcheck-am:
+
+maintainer-clean: maintainer-clean-am
+		-rm -f ./$(DEPDIR)/pop3c-client.Plo
+	-rm -f ./$(DEPDIR)/pop3c-mail.Plo
+	-rm -f ./$(DEPDIR)/pop3c-settings.Plo
+	-rm -f ./$(DEPDIR)/pop3c-storage.Plo
+	-rm -f ./$(DEPDIR)/pop3c-sync.Plo
+	-rm -f Makefile
+maintainer-clean-am: distclean-am maintainer-clean-generic
+
+mostlyclean: mostlyclean-am
+
+mostlyclean-am: mostlyclean-compile mostlyclean-generic \
+	mostlyclean-libtool
+
+pdf: pdf-am
+
+pdf-am:
+
+ps: ps-am
+
+ps-am:
+
+uninstall-am: uninstall-pkginc_libHEADERS
+
+.MAKE: install-am install-strip
+
+.PHONY: CTAGS GTAGS TAGS all all-am am--depfiles check check-am clean \
+	clean-generic clean-libtool clean-noinstLTLIBRARIES \
+	cscopelist-am ctags ctags-am distclean distclean-compile \
+	distclean-generic distclean-libtool distclean-tags distdir dvi \
+	dvi-am html html-am info info-am install install-am \
+	install-data install-data-am install-dvi install-dvi-am \
+	install-exec install-exec-am install-html install-html-am \
+	install-info install-info-am install-man install-pdf \
+	install-pdf-am install-pkginc_libHEADERS install-ps \
+	install-ps-am install-strip installcheck installcheck-am \
+	installdirs maintainer-clean maintainer-clean-generic \
+	mostlyclean mostlyclean-compile mostlyclean-generic \
+	mostlyclean-libtool pdf pdf-am ps ps-am tags tags-am uninstall \
+	uninstall-am uninstall-pkginc_libHEADERS
+
+.PRECIOUS: Makefile
+
+
+# Tell versions [3.59,3.63) of GNU make to not export all variables.
+# Otherwise a system limit (for SysV at least) may be exceeded.
+.NOEXPORT:
diff --git a/src/lib-storage/index/pop3c/pop3c-client.c b/src/lib-storage/index/pop3c/pop3c-client.c
new file mode 100644
index 0000000..44544a3
--- /dev/null
+++ b/src/lib-storage/index/pop3c/pop3c-client.c
@@ -0,0 +1,902 @@
+/* Copyright (c) 2011-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "array.h"
+#include "ioloop.h"
+#include "net.h"
+#include "istream.h"
+#include "istream-chain.h"
+#include "istream-dot.h"
+#include "istream-seekable.h"
+#include "ostream.h"
+#include "iostream-rawlog.h"
+#include "iostream-ssl.h"
+#include "safe-mkstemp.h"
+#include "base64.h"
+#include "str.h"
+#include "dns-lookup.h"
+#include "pop3c-client.h"
+
+#include <unistd.h>
+
+#define POP3C_MAX_INBUF_SIZE (1024*32)
+#define POP3C_DNS_LOOKUP_TIMEOUT_MSECS (1000*30)
+#define POP3C_CONNECT_TIMEOUT_MSECS (1000*30)
+#define POP3C_COMMAND_TIMEOUT_MSECS (1000*60*5)
+
+enum pop3c_client_state {
+	/* No connection */
+	POP3C_CLIENT_STATE_DISCONNECTED = 0,
+	/* Trying to connect */
+	POP3C_CLIENT_STATE_CONNECTING,
+	POP3C_CLIENT_STATE_STARTTLS,
+	/* Connected, trying to authenticate */
+	POP3C_CLIENT_STATE_USER,
+	POP3C_CLIENT_STATE_AUTH,
+	POP3C_CLIENT_STATE_PASS,
+	/* Post-authentication, asking for capabilities */
+	POP3C_CLIENT_STATE_CAPA,
+	/* Authenticated, ready to accept commands */
+	POP3C_CLIENT_STATE_DONE
+};
+
+struct pop3c_client_sync_cmd_ctx {
+	enum pop3c_command_state state;
+	char *reply;
+};
+
+struct pop3c_client_cmd {
+	struct istream *input;
+	struct istream_chain *chain;
+	bool reading_dot;
+
+	pop3c_cmd_callback_t *callback;
+	void *context;
+};
+
+struct pop3c_client {
+	pool_t pool;
+	struct event *event;
+	struct pop3c_client_settings set;
+	struct ssl_iostream_context *ssl_ctx;
+	struct ip_addr ip;
+
+	int fd;
+	struct io *io;
+	struct istream *input, *raw_input;
+	struct ostream *output, *raw_output;
+	struct ssl_iostream *ssl_iostream;
+	struct timeout *to;
+	struct dns_lookup *dns_lookup;
+
+	enum pop3c_client_state state;
+	enum pop3c_capability capabilities;
+	const char *auth_mech;
+
+	pop3c_login_callback_t *login_callback;
+	void *login_context;
+
+	ARRAY(struct pop3c_client_cmd) commands;
+	const char *input_line;
+	struct istream *dot_input;
+
+	bool running:1;
+};
+
+static void
+pop3c_dns_callback(const struct dns_lookup_result *result,
+		   struct pop3c_client *client);
+static void pop3c_client_connect_ip(struct pop3c_client *client);
+static int pop3c_client_ssl_init(struct pop3c_client *client);
+static void pop3c_client_input(struct pop3c_client *client);
+
+struct pop3c_client *
+pop3c_client_init(const struct pop3c_client_settings *set,
+		  struct event *event_parent)
+{
+	struct pop3c_client *client;
+	const char *error;
+	pool_t pool;
+
+	pool = pool_alloconly_create("pop3c client", 1024);
+	client = p_new(pool, struct pop3c_client, 1);
+	client->pool = pool;
+	client->event = event_create(event_parent);
+	client->fd = -1;
+	p_array_init(&client->commands, pool, 16);
+
+	client->set.debug = set->debug;
+	client->set.host = p_strdup(pool, set->host);
+	client->set.port = set->port;
+	client->set.master_user = p_strdup_empty(pool, set->master_user);
+	client->set.username = p_strdup(pool, set->username);
+	client->set.password = p_strdup(pool, set->password);
+	client->set.dns_client_socket_path =
+		p_strdup(pool, set->dns_client_socket_path);
+	client->set.temp_path_prefix = p_strdup(pool, set->temp_path_prefix);
+	client->set.rawlog_dir = p_strdup(pool, set->rawlog_dir);
+	client->set.ssl_mode = set->ssl_mode;
+
+	if (set->ssl_mode != POP3C_CLIENT_SSL_MODE_NONE) {
+		ssl_iostream_settings_init_from(client->pool, &client->set.ssl_set, &set->ssl_set);
+		client->set.ssl_set.verbose_invalid_cert = !client->set.ssl_set.allow_invalid_cert;
+		if (ssl_iostream_client_context_cache_get(&set->ssl_set,
+							  &client->ssl_ctx,
+							  &error) < 0) {
+			i_error("pop3c(%s:%u): Couldn't initialize SSL context: %s",
+				set->host, set->port, error);
+		}
+	}
+	return client;
+}
+
+static void
+client_login_callback(struct pop3c_client *client,
+		      enum pop3c_command_state state, const char *reason)
+{
+	pop3c_login_callback_t *callback = client->login_callback;
+	void *context = client->login_context;
+
+	if (client->login_callback != NULL) {
+		client->login_callback = NULL;
+		client->login_context = NULL;
+		callback(state, reason, context);
+	}
+}
+
+static void
+pop3c_client_async_callback(struct pop3c_client *client,
+			    enum pop3c_command_state state, const char *reply)
+{
+	struct pop3c_client_cmd *cmd, cmd_copy;
+	bool running = client->running;
+
+	i_assert(reply != NULL);
+	i_assert(array_count(&client->commands) > 0);
+
+	cmd = array_front_modifiable(&client->commands);
+	if (cmd->input != NULL && state == POP3C_COMMAND_STATE_OK &&
+	    !cmd->reading_dot) {
+		/* read the full input into seekable-istream before calling
+		   the callback */
+		i_assert(client->dot_input == NULL);
+		i_stream_chain_append(cmd->chain, client->input);
+		client->dot_input = cmd->input;
+		cmd->reading_dot = TRUE;
+		return;
+	}
+	cmd_copy = *cmd;
+	array_pop_front(&client->commands);
+
+	if (cmd_copy.input != NULL) {
+		i_stream_seek(cmd_copy.input, 0);
+		i_stream_unref(&cmd_copy.input);
+	}
+	if (cmd_copy.callback != NULL)
+		cmd_copy.callback(state, reply, cmd_copy.context);
+	if (running)
+		io_loop_stop(current_ioloop);
+}
+
+static void
+pop3c_client_async_callback_disconnected(struct pop3c_client *client)
+{
+	pop3c_client_async_callback(client, POP3C_COMMAND_STATE_DISCONNECTED,
+				    "Disconnected");
+}
+
+static void pop3c_client_disconnect(struct pop3c_client *client)
+{
+	client->state = POP3C_CLIENT_STATE_DISCONNECTED;
+
+	if (client->running)
+		io_loop_stop(current_ioloop);
+
+	if (client->dns_lookup != NULL)
+		dns_lookup_abort(&client->dns_lookup);
+	timeout_remove(&client->to);
+	io_remove(&client->io);
+	i_stream_destroy(&client->input);
+	o_stream_destroy(&client->output);
+	ssl_iostream_destroy(&client->ssl_iostream);
+	i_close_fd(&client->fd);
+	while (array_count(&client->commands) > 0)
+		pop3c_client_async_callback_disconnected(client);
+	client_login_callback(client, POP3C_COMMAND_STATE_DISCONNECTED,
+			      "Disconnected");
+}
+
+void pop3c_client_deinit(struct pop3c_client **_client)
+{
+	struct pop3c_client *client = *_client;
+
+	pop3c_client_disconnect(client);
+	if (client->ssl_ctx != NULL)
+		ssl_iostream_context_unref(&client->ssl_ctx);
+	event_unref(&client->event);
+	pool_unref(&client->pool);
+}
+
+static void pop3c_client_ioloop_changed(struct pop3c_client *client)
+{
+	if (client->to != NULL)
+		client->to = io_loop_move_timeout(&client->to);
+	if (client->io != NULL)
+		client->io = io_loop_move_io(&client->io);
+	if (client->output != NULL)
+		o_stream_switch_ioloop(client->output);
+}
+
+static void pop3c_client_timeout(struct pop3c_client *client)
+{
+	switch (client->state) {
+	case POP3C_CLIENT_STATE_CONNECTING:
+		i_error("pop3c(%s): connect(%s, %u) timed out after %u seconds",
+			client->set.host, net_ip2addr(&client->ip),
+			client->set.port, POP3C_CONNECT_TIMEOUT_MSECS/1000);
+		break;
+	case POP3C_CLIENT_STATE_DONE:
+		i_error("pop3c(%s): Command timed out after %u seconds",
+			client->set.host, POP3C_COMMAND_TIMEOUT_MSECS/1000);
+		break;
+	default:
+		i_error("pop3c(%s): Authentication timed out after %u seconds",
+			client->set.host, POP3C_CONNECT_TIMEOUT_MSECS/1000);
+		break;
+	}
+	pop3c_client_disconnect(client);
+}
+
+static int pop3c_client_dns_lookup(struct pop3c_client *client)
+{
+	struct dns_lookup_settings dns_set;
+
+	i_assert(client->state == POP3C_CLIENT_STATE_CONNECTING);
+
+	if (client->set.dns_client_socket_path[0] == '\0') {
+		struct ip_addr *ips;
+		unsigned int ips_count;
+		int ret;
+
+		ret = net_gethostbyname(client->set.host, &ips, &ips_count);
+		if (ret != 0) {
+			i_error("pop3c(%s): net_gethostbyname() failed: %s",
+				client->set.host, net_gethosterror(ret));
+			return -1;
+		}
+		i_assert(ips_count > 0);
+		client->ip = ips[0];
+		pop3c_client_connect_ip(client);
+	} else {
+		i_zero(&dns_set);
+		dns_set.dns_client_socket_path =
+			client->set.dns_client_socket_path;
+		dns_set.timeout_msecs = POP3C_DNS_LOOKUP_TIMEOUT_MSECS;
+		dns_set.event_parent = client->event;
+		if (dns_lookup(client->set.host, &dns_set,
+			       pop3c_dns_callback, client,
+			       &client->dns_lookup) < 0)
+			return -1;
+	}
+	return 0;
+}
+
+void pop3c_client_wait_one(struct pop3c_client *client)
+{
+	struct ioloop *ioloop, *prev_ioloop = current_ioloop;
+	bool timeout_added = FALSE, failed = FALSE;
+
+	if (client->state == POP3C_CLIENT_STATE_DISCONNECTED &&
+	    array_count(&client->commands) > 0) {
+		while (array_count(&client->commands) > 0)
+			pop3c_client_async_callback_disconnected(client);
+		return;
+	}
+
+	i_assert(client->fd != -1 ||
+		 client->state == POP3C_CLIENT_STATE_CONNECTING);
+	i_assert(array_count(&client->commands) > 0 ||
+		 client->state == POP3C_CLIENT_STATE_CONNECTING);
+
+	ioloop = io_loop_create();
+	pop3c_client_ioloop_changed(client);
+
+	if (client->ip.family == 0) {
+		/* we're connecting, start DNS lookup after our ioloop
+		   is created */
+		if (pop3c_client_dns_lookup(client) < 0)
+			failed = TRUE;
+	} else if (client->to == NULL) {
+		client->to = timeout_add(POP3C_COMMAND_TIMEOUT_MSECS,
+					 pop3c_client_timeout, client);
+		timeout_added = TRUE;
+	}
+
+	if (!failed) {
+		client->running = TRUE;
+		io_loop_run(ioloop);
+		client->running = FALSE;
+	}
+
+	if (timeout_added && client->to != NULL)
+		timeout_remove(&client->to);
+
+	io_loop_set_current(prev_ioloop);
+	pop3c_client_ioloop_changed(client);
+	io_loop_set_current(ioloop);
+	io_loop_destroy(&ioloop);
+}
+
+static void pop3c_client_starttls(struct pop3c_client *client)
+{
+	o_stream_nsend_str(client->output, "STLS\r\n");
+	client->state = POP3C_CLIENT_STATE_STARTTLS;
+}
+
+static void pop3c_client_authenticate1(struct pop3c_client *client)
+{
+	const struct pop3c_client_settings *set = &client->set;
+
+	if (client->set.debug) {
+		if (set->master_user == NULL) {
+			i_debug("pop3c(%s): Authenticating as '%s' (with USER+PASS)",
+				client->set.host, set->username);
+		} else {
+			i_debug("pop3c(%s): Authenticating as master user '%s' for user '%s' (with SASL PLAIN)",
+				client->set.host, set->master_user,
+				set->username);
+		}
+	}
+
+	if (set->master_user == NULL) {
+		o_stream_nsend_str(client->output,
+			t_strdup_printf("USER %s\r\n", set->username));
+		client->state = POP3C_CLIENT_STATE_USER;
+	} else {
+		client->state = POP3C_CLIENT_STATE_AUTH;
+		o_stream_nsend_str(client->output, "AUTH PLAIN\r\n");
+	}
+}
+
+static const char *
+pop3c_client_get_sasl_plain_request(struct pop3c_client *client)
+{
+	const struct pop3c_client_settings *set = &client->set;
+	string_t *in, *out;
+
+	in = t_str_new(128);
+	if (set->master_user != NULL) {
+		str_append(in, set->username);
+		str_append_c(in, '\0');
+		str_append(in, set->master_user);
+	} else {
+		str_append_c(in, '\0');
+		str_append(in, set->username);
+	}
+	str_append_c(in, '\0');
+	str_append(in, set->password);
+
+	out = t_str_new(128);
+	base64_encode(str_data(in), str_len(in), out);
+	str_append(out, "\r\n");
+	return str_c(out);
+}
+
+static void pop3c_client_login_finished(struct pop3c_client *client)
+{
+	io_remove(&client->io);
+	client->io = io_add(client->fd, IO_READ, pop3c_client_input, client);
+
+	timeout_remove(&client->to);
+	client->state = POP3C_CLIENT_STATE_DONE;
+
+	if (client->running)
+		io_loop_stop(current_ioloop);
+}
+
+static int
+pop3c_client_prelogin_input_line(struct pop3c_client *client, const char *line)
+{
+	bool success = line[0] == '+';
+	const char *reply;
+
+	switch (client->state) {
+	case POP3C_CLIENT_STATE_CONNECTING:
+		if (!success) {
+			i_error("pop3c(%s): Server sent invalid banner: %s",
+				client->set.host, line);
+			return -1;
+		}
+		if (client->set.ssl_mode == POP3C_CLIENT_SSL_MODE_STARTTLS)
+			pop3c_client_starttls(client);
+		else
+			pop3c_client_authenticate1(client);
+		break;
+	case POP3C_CLIENT_STATE_STARTTLS:
+		if (!success) {
+			i_error("pop3c(%s): STLS failed: %s",
+				client->set.host, line);
+			return -1;
+		}
+		if (pop3c_client_ssl_init(client) < 0)
+			pop3c_client_disconnect(client);
+		break;
+	case POP3C_CLIENT_STATE_USER:
+		if (!success) {
+			i_error("pop3c(%s): USER failed: %s",
+				client->set.host, line);
+			return -1;
+		}
+
+		/* the PASS reply can take a long time.
+		   switch to command timeout. */
+		timeout_remove(&client->to);
+		client->to = timeout_add(POP3C_COMMAND_TIMEOUT_MSECS,
+					 pop3c_client_timeout, client);
+
+		o_stream_nsend_str(client->output,
+			t_strdup_printf("PASS %s\r\n", client->set.password));
+		client->state = POP3C_CLIENT_STATE_PASS;
+		client->auth_mech = "USER+PASS";
+		break;
+	case POP3C_CLIENT_STATE_AUTH:
+		if (line[0] != '+') {
+			i_error("pop3c(%s): AUTH PLAIN failed: %s",
+				client->set.host, line);
+			return -1;
+		}
+		o_stream_nsend_str(client->output,
+			pop3c_client_get_sasl_plain_request(client));
+		client->state = POP3C_CLIENT_STATE_PASS;
+		client->auth_mech = "AUTH PLAIN";
+		break;
+	case POP3C_CLIENT_STATE_PASS:
+		if (client->login_callback != NULL) {
+			reply = strncasecmp(line, "+OK ", 4) == 0 ? line + 4 :
+				strncasecmp(line, "-ERR ", 5) == 0 ? line + 5 :
+				line;
+			client_login_callback(client, success ?
+					      POP3C_COMMAND_STATE_OK :
+					      POP3C_COMMAND_STATE_ERR, reply);
+		} else if (!success) {
+			i_error("pop3c(%s): Authentication via %s failed: %s",
+				client->set.host, client->auth_mech, line);
+		}
+		if (!success)
+			return -1;
+
+		o_stream_nsend_str(client->output, "CAPA\r\n");
+		client->state = POP3C_CLIENT_STATE_CAPA;
+		break;
+	case POP3C_CLIENT_STATE_CAPA:
+		if (strncasecmp(line, "-ERR", 4) == 0) {
+			/* CAPA command not supported. some commands still
+			   support UIDL though. */
+			client->capabilities |= POP3C_CAPABILITY_UIDL;
+			pop3c_client_login_finished(client);
+			break;
+		} else if (strcmp(line, ".") == 0) {
+			pop3c_client_login_finished(client);
+			break;
+		}
+		if ((client->set.parsed_features & POP3C_FEATURE_NO_PIPELINING) == 0 &&
+		    strcasecmp(line, "PIPELINING") == 0)
+			client->capabilities |= POP3C_CAPABILITY_PIPELINING;
+		else if (strcasecmp(line, "TOP") == 0)
+			client->capabilities |= POP3C_CAPABILITY_TOP;
+		else if (strcasecmp(line, "UIDL") == 0)
+			client->capabilities |= POP3C_CAPABILITY_UIDL;
+		break;
+	case POP3C_CLIENT_STATE_DISCONNECTED:
+	case POP3C_CLIENT_STATE_DONE:
+		i_unreached();
+	}
+	return 0;
+}
+
+static void pop3c_client_prelogin_input(struct pop3c_client *client)
+{
+	const char *line, *errstr;
+
+	i_assert(client->state != POP3C_CLIENT_STATE_DONE);
+
+	/* we need to read as much as we can with SSL streams to avoid
+	   hanging */
+	while ((line = i_stream_read_next_line(client->input)) != NULL) {
+		if (pop3c_client_prelogin_input_line(client, line) < 0) {
+			pop3c_client_disconnect(client);
+			return;
+		}
+	}
+
+	if (client->input->closed || client->input->eof ||
+	    client->input->stream_errno != 0) {
+		/* disconnected */
+		if (client->ssl_iostream == NULL) {
+			i_error("pop3c(%s): Server disconnected unexpectedly",
+				client->set.host);
+		} else {
+			errstr = ssl_iostream_get_last_error(client->ssl_iostream);
+			if (errstr == NULL) {
+				errstr = client->input->stream_errno == 0 ? "EOF" :
+					strerror(client->input->stream_errno);
+			}
+			i_error("pop3c(%s): Server disconnected: %s",
+				client->set.host, errstr);
+		}
+		pop3c_client_disconnect(client);
+	}
+}
+
+static int pop3c_client_ssl_handshaked(const char **error_r, void *context)
+{
+	struct pop3c_client *client = context;
+	const char *error;
+
+	if (ssl_iostream_check_cert_validity(client->ssl_iostream,
+					     client->set.host, &error) == 0) {
+		if (client->set.debug) {
+			i_debug("pop3c(%s): SSL handshake successful",
+				client->set.host);
+		}
+		return 0;
+	} else if (client->set.ssl_set.allow_invalid_cert) {
+		if (client->set.debug) {
+			i_debug("pop3c(%s): SSL handshake successful, "
+				"ignoring invalid certificate: %s",
+				client->set.host, error);
+		}
+		return 0;
+	} else {
+		*error_r = error;
+		return -1;
+	}
+}
+
+static int pop3c_client_ssl_init(struct pop3c_client *client)
+{
+	const char *error;
+
+	if (client->ssl_ctx == NULL) {
+		i_error("pop3c(%s): No SSL context", client->set.host);
+		return -1;
+	}
+
+	if (client->set.debug)
+		i_debug("pop3c(%s): Starting SSL handshake", client->set.host);
+
+	if (client->raw_input != client->input) {
+		/* recreate rawlog after STARTTLS */
+		i_stream_ref(client->raw_input);
+		o_stream_ref(client->raw_output);
+		i_stream_destroy(&client->input);
+		o_stream_destroy(&client->output);
+		client->input = client->raw_input;
+		client->output = client->raw_output;
+	}
+
+	if (io_stream_create_ssl_client(client->ssl_ctx, client->set.host,
+					&client->set.ssl_set, &client->input,
+					&client->output, &client->ssl_iostream, &error) < 0) {
+		i_error("pop3c(%s): Couldn't initialize SSL client: %s",
+			client->set.host, error);
+		return -1;
+	}
+	ssl_iostream_set_handshake_callback(client->ssl_iostream,
+					    pop3c_client_ssl_handshaked,
+					    client);
+	if (ssl_iostream_handshake(client->ssl_iostream) < 0) {
+		i_error("pop3c(%s): SSL handshake failed: %s", client->set.host,
+			ssl_iostream_get_last_error(client->ssl_iostream));
+		return -1;
+	}
+
+	if (*client->set.rawlog_dir != '\0') {
+		iostream_rawlog_create(client->set.rawlog_dir,
+				       &client->input, &client->output);
+	}
+	return 0;
+}
+
+static void pop3c_client_connected(struct pop3c_client *client)
+{
+	int err;
+
+	err = net_geterror(client->fd);
+	if (err != 0) {
+		i_error("pop3c(%s): connect(%s, %u) failed: %s",
+			client->set.host, net_ip2addr(&client->ip),
+			client->set.port, strerror(err));
+		pop3c_client_disconnect(client);
+		return;
+	}
+	io_remove(&client->io);
+	client->io = io_add(client->fd, IO_READ,
+			    pop3c_client_prelogin_input, client);
+
+	if (client->set.ssl_mode == POP3C_CLIENT_SSL_MODE_IMMEDIATE) {
+		if (pop3c_client_ssl_init(client) < 0)
+			pop3c_client_disconnect(client);
+	}
+}
+
+static void pop3c_client_connect_ip(struct pop3c_client *client)
+{
+	client->fd = net_connect_ip(&client->ip, client->set.port, NULL);
+	if (client->fd == -1) {
+		pop3c_client_disconnect(client);
+		return;
+	}
+
+	client->input = client->raw_input =
+		i_stream_create_fd(client->fd, POP3C_MAX_INBUF_SIZE);
+	client->output = client->raw_output =
+		o_stream_create_fd(client->fd, SIZE_MAX);
+	o_stream_set_no_error_handling(client->output, TRUE);
+
+	if (*client->set.rawlog_dir != '\0' &&
+	    client->set.ssl_mode != POP3C_CLIENT_SSL_MODE_IMMEDIATE) {
+		iostream_rawlog_create(client->set.rawlog_dir,
+				       &client->input, &client->output);
+	}
+	client->io = io_add(client->fd, IO_WRITE,
+			    pop3c_client_connected, client);
+	client->to = timeout_add(POP3C_CONNECT_TIMEOUT_MSECS,
+				 pop3c_client_timeout, client);
+	if (client->set.debug) {
+		i_debug("pop3c(%s): Connecting to %s:%u", client->set.host,
+			net_ip2addr(&client->ip), client->set.port);
+	}
+}
+
+static void
+pop3c_dns_callback(const struct dns_lookup_result *result,
+		   struct pop3c_client *client)
+{
+	client->dns_lookup = NULL;
+
+	if (result->ret != 0) {
+		i_error("pop3c(%s): dns_lookup() failed: %s",
+			client->set.host, result->error);
+		pop3c_client_disconnect(client);
+		return;
+	}
+
+	i_assert(result->ips_count > 0);
+	client->ip = result->ips[0];
+	pop3c_client_connect_ip(client);
+}
+
+void pop3c_client_login(struct pop3c_client *client,
+			pop3c_login_callback_t *callback, void *context)
+{
+	if (client->fd != -1) {
+		i_assert(callback == NULL);
+		return;
+	}
+	i_assert(client->login_callback == NULL);
+	client->login_callback = callback;
+	client->login_context = context;
+	client->state = POP3C_CLIENT_STATE_CONNECTING;
+
+	if (client->set.debug)
+		i_debug("pop3c(%s): Looking up IP address", client->set.host);
+}
+
+bool pop3c_client_is_connected(struct pop3c_client *client)
+{
+	return client->fd != -1;
+}
+
+enum pop3c_capability
+pop3c_client_get_capabilities(struct pop3c_client *client)
+{
+	return client->capabilities;
+}
+
+static int pop3c_client_dot_input(struct pop3c_client *client)
+{
+	ssize_t ret;
+
+	while ((ret = i_stream_read(client->dot_input)) > 0 || ret == -2) {
+		i_stream_skip(client->dot_input,
+			      i_stream_get_data_size(client->dot_input));
+	}
+	if (ret == 0)
+		return 0;
+	i_assert(ret == -1);
+
+	if (client->dot_input->stream_errno == 0)
+		ret = 1;
+	client->dot_input = NULL;
+
+	if (ret > 0) {
+		/* currently we don't actually care about preserving the
+		   +OK reply line for multi-line replies, so just return
+		   it as empty */
+		pop3c_client_async_callback(client, POP3C_COMMAND_STATE_OK, "");
+		return 1;
+	} else {
+		pop3c_client_async_callback_disconnected(client);
+		return -1;
+	}
+}
+
+static int
+pop3c_client_input_next_reply(struct pop3c_client *client)
+{
+	const char *line;
+	enum pop3c_command_state state;
+
+	line = i_stream_read_next_line(client->input);
+	if (line == NULL)
+		return client->input->eof ? -1 : 0;
+
+	if (strncasecmp(line, "+OK", 3) == 0) {
+		line += 3;
+		state = POP3C_COMMAND_STATE_OK;
+	} else if (strncasecmp(line, "-ERR", 4) == 0) {
+		line += 4;
+		state = POP3C_COMMAND_STATE_ERR;
+	} else {
+		i_error("pop3c(%s): Server sent unrecognized line: %s",
+			client->set.host, line);
+		state = POP3C_COMMAND_STATE_ERR;
+	}
+	if (line[0] == ' ')
+		line++;
+	if (array_count(&client->commands) == 0) {
+		i_error("pop3c(%s): Server sent line when no command was running: %s",
+			client->set.host, line);
+	} else {
+		pop3c_client_async_callback(client, state, line);
+	}
+	return 1;
+}
+
+static void pop3c_client_input(struct pop3c_client *client)
+{
+	int ret;
+
+	if (client->to != NULL)
+		timeout_reset(client->to);
+	do {
+		if (client->dot_input != NULL) {
+			/* continue reading the current multiline reply */
+			if ((ret = pop3c_client_dot_input(client)) == 0)
+				return;
+		} else {
+			ret = pop3c_client_input_next_reply(client);
+		}
+	} while (ret > 0);
+
+	if (ret < 0) {
+		i_error("pop3c(%s): Server disconnected unexpectedly",
+			client->set.host);
+		pop3c_client_disconnect(client);
+	}
+}
+
+static void pop3c_client_cmd_reply(enum pop3c_command_state state,
+				   const char *reply, void *context)
+{
+	struct pop3c_client_sync_cmd_ctx *ctx = context;
+
+	i_assert(ctx->reply == NULL);
+
+	ctx->state = state;
+	ctx->reply = i_strdup(reply);
+}
+
+int pop3c_client_cmd_line(struct pop3c_client *client, const char *cmdline,
+			  const char **reply_r)
+{
+	struct pop3c_client_sync_cmd_ctx ctx;
+
+	i_zero(&ctx);
+	pop3c_client_cmd_line_async(client, cmdline, pop3c_client_cmd_reply, &ctx);
+	while (ctx.reply == NULL)
+		pop3c_client_wait_one(client);
+	*reply_r = t_strdup(ctx.reply);
+	i_free(ctx.reply);
+	return ctx.state == POP3C_COMMAND_STATE_OK ? 0 : -1;
+}
+
+struct pop3c_client_cmd *
+pop3c_client_cmd_line_async(struct pop3c_client *client, const char *cmdline,
+			    pop3c_cmd_callback_t *callback, void *context)
+{
+	struct pop3c_client_cmd *cmd;
+
+	if ((client->capabilities & POP3C_CAPABILITY_PIPELINING) == 0) {
+		while (array_count(&client->commands) > 0)
+			pop3c_client_wait_one(client);
+	}
+	i_assert(client->state == POP3C_CLIENT_STATE_DISCONNECTED ||
+		 client->state == POP3C_CLIENT_STATE_DONE);
+	if (client->state == POP3C_CLIENT_STATE_DONE)
+		o_stream_nsend_str(client->output, cmdline);
+
+	cmd = array_append_space(&client->commands);
+	cmd->callback = callback;
+	cmd->context = context;
+	return cmd;
+}
+
+void pop3c_client_cmd_line_async_nocb(struct pop3c_client *client,
+				      const char *cmdline)
+{
+	pop3c_client_cmd_line_async(client, cmdline, NULL, NULL);
+}
+
+static int seekable_fd_callback(const char **path_r, void *context)
+{
+	struct pop3c_client *client = context;
+	string_t *path;
+	int fd;
+
+	path = t_str_new(128);
+	str_append(path, client->set.temp_path_prefix);
+	fd = safe_mkstemp(path, 0600, (uid_t)-1, (gid_t)-1);
+	if (fd == -1) {
+		i_error("safe_mkstemp(%s) failed: %m", str_c(path));
+		return -1;
+	}
+
+	/* we just want the fd, unlink it */
+	if (i_unlink(str_c(path)) < 0) {
+		/* shouldn't happen.. */
+		i_close_fd(&fd);
+		return -1;
+	}
+
+	*path_r = str_c(path);
+	return fd;
+}
+
+int pop3c_client_cmd_stream(struct pop3c_client *client, const char *cmdline,
+			    struct istream **input_r, const char **error_r)
+{
+	struct pop3c_client_sync_cmd_ctx ctx;
+	const char *reply;
+
+	if (client->state == POP3C_CLIENT_STATE_DISCONNECTED) {
+		*error_r = "Disconnected from server";
+		return -1;
+	}
+
+	i_zero(&ctx);
+	*input_r = pop3c_client_cmd_stream_async(client, cmdline,
+						 pop3c_client_cmd_reply, &ctx);
+	while (ctx.reply == NULL)
+		pop3c_client_wait_one(client);
+	reply = t_strdup(ctx.reply);
+	i_free(ctx.reply);
+
+	if (ctx.state == POP3C_COMMAND_STATE_OK)
+		return 0;
+	i_stream_unref(input_r);
+	*error_r = reply;
+	return -1;
+}
+
+struct istream *
+pop3c_client_cmd_stream_async(struct pop3c_client *client, const char *cmdline,
+			      pop3c_cmd_callback_t *callback, void *context)
+{
+	struct istream *input, *inputs[2];
+	struct pop3c_client_cmd *cmd;
+
+	cmd = pop3c_client_cmd_line_async(client, cmdline, callback, context);
+
+	input = i_stream_create_chain(&cmd->chain, POP3C_MAX_INBUF_SIZE);
+	inputs[0] = i_stream_create_dot(input, TRUE);
+	inputs[1] = NULL;
+	cmd->input = i_stream_create_seekable(inputs, POP3C_MAX_INBUF_SIZE,
+					      seekable_fd_callback, client);
+	i_stream_unref(&input);
+	i_stream_unref(&inputs[0]);
+
+	i_stream_ref(cmd->input);
+	return cmd->input;
+}
diff --git a/src/lib-storage/index/pop3c/pop3c-client.h b/src/lib-storage/index/pop3c/pop3c-client.h
new file mode 100644
index 0000000..f0bbd64
--- /dev/null
+++ b/src/lib-storage/index/pop3c/pop3c-client.h
@@ -0,0 +1,86 @@
+#ifndef POP3C_CLIENT_H
+#define POP3C_CLIENT_H
+
+#include "net.h"
+#include "pop3c-settings.h"
+#include "iostream-ssl.h"
+
+enum pop3c_capability {
+	POP3C_CAPABILITY_PIPELINING	= 0x01,
+	POP3C_CAPABILITY_TOP		= 0x02,
+	POP3C_CAPABILITY_UIDL		= 0x04
+};
+
+enum pop3c_command_state {
+	POP3C_COMMAND_STATE_OK,
+	POP3C_COMMAND_STATE_ERR,
+	POP3C_COMMAND_STATE_DISCONNECTED
+};
+
+enum pop3c_client_ssl_mode {
+	POP3C_CLIENT_SSL_MODE_NONE,
+	POP3C_CLIENT_SSL_MODE_IMMEDIATE,
+	POP3C_CLIENT_SSL_MODE_STARTTLS
+};
+
+struct pop3c_client_settings {
+	const char *host;
+	in_port_t port;
+
+	const char *master_user;
+	const char *username;
+	const char *password;
+
+	const char *dns_client_socket_path;
+	const char *temp_path_prefix;
+
+	enum pop3c_client_ssl_mode ssl_mode;
+	enum pop3c_features parsed_features;
+	struct ssl_iostream_settings ssl_set;
+
+	const char *rawlog_dir;
+	const char *ssl_crypto_device;
+	bool debug;
+};
+
+typedef void pop3c_login_callback_t(enum pop3c_command_state state,
+				    const char *reply, void *context);
+typedef void pop3c_cmd_callback_t(enum pop3c_command_state state,
+				  const char *reply, void *context);
+
+struct pop3c_client *
+pop3c_client_init(const struct pop3c_client_settings *set,
+		  struct event *event_parent);
+void pop3c_client_deinit(struct pop3c_client **client);
+
+void pop3c_client_login(struct pop3c_client *client,
+			pop3c_login_callback_t *callback, void *context);
+
+bool pop3c_client_is_connected(struct pop3c_client *client);
+enum pop3c_capability
+pop3c_client_get_capabilities(struct pop3c_client *client);
+
+/* Returns 0 if received +OK reply, reply contains the text without the +OK.
+   Returns -1 if received -ERR reply or disconnected. */
+int pop3c_client_cmd_line(struct pop3c_client *client, const char *cmdline,
+			  const char **reply_r);
+/* Start the command asynchronously. Call the callback when finished. */
+struct pop3c_client_cmd *
+pop3c_client_cmd_line_async(struct pop3c_client *client, const char *cmdline,
+			    pop3c_cmd_callback_t *callback, void *context);
+/* Send a command, don't care if it succeeds or not. */
+void pop3c_client_cmd_line_async_nocb(struct pop3c_client *client,
+				      const char *cmdline);
+/* Returns 0 and stream if succeeded, -1 and error if received -ERR reply or
+   disconnected. */
+int pop3c_client_cmd_stream(struct pop3c_client *client, const char *cmdline,
+			    struct istream **input_r, const char **error_r);
+/* Start the command asynchronously. Call the callback when finished. */
+struct istream *
+pop3c_client_cmd_stream_async(struct pop3c_client *client, const char *cmdline,
+			      pop3c_cmd_callback_t *callback, void *context);
+/* Wait for the next async command to finish. It's an error to call this when
+   there are no pending async commands. */
+void pop3c_client_wait_one(struct pop3c_client *client);
+
+#endif
diff --git a/src/lib-storage/index/pop3c/pop3c-mail.c b/src/lib-storage/index/pop3c/pop3c-mail.c
new file mode 100644
index 0000000..27a8427
--- /dev/null
+++ b/src/lib-storage/index/pop3c/pop3c-mail.c
@@ -0,0 +1,304 @@
+/* Copyright (c) 2011-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "ioloop.h"
+#include "istream.h"
+#include "index-mail.h"
+#include "pop3c-client.h"
+#include "pop3c-sync.h"
+#include "pop3c-storage.h"
+
+struct mail *
+pop3c_mail_alloc(struct mailbox_transaction_context *t,
+		 enum mail_fetch_field wanted_fields,
+		 struct mailbox_header_lookup_ctx *wanted_headers)
+{
+	struct pop3c_mail *mail;
+	pool_t pool;
+
+	pool = pool_alloconly_create("mail", 2048);
+	mail = p_new(pool, struct pop3c_mail, 1);
+
+	index_mail_init(&mail->imail, t, wanted_fields, wanted_headers, pool, NULL);
+	return &mail->imail.mail.mail;
+}
+
+static void pop3c_mail_close(struct mail *_mail)
+{
+	struct pop3c_mail *pmail = POP3C_MAIL(_mail);
+	struct pop3c_mailbox *mbox = POP3C_MAILBOX(_mail->box);
+
+	/* wait for any prefetch to finish before closing the mail */
+	while (pmail->prefetching)
+		pop3c_client_wait_one(mbox->client);
+	i_stream_unref(&pmail->prefetch_stream);
+	index_mail_close(_mail);
+}
+
+static int pop3c_mail_get_received_date(struct mail *_mail, time_t *date_r)
+{
+	struct pop3c_mailbox *mbox = POP3C_MAILBOX(_mail->box);
+	int tz;
+
+	if (mbox->storage->set->pop3c_quick_received_date) {
+		/* we don't care about the date, just return the current date */
+		*date_r = ioloop_time;
+		return 0;
+	}
+
+	/* FIXME: we could also parse the first Received: header and get
+	   the date from there, but since this code is unlikely to be called
+	   except during migration, I don't think it really matters. */
+	return index_mail_get_date(_mail, date_r, &tz);
+}
+
+static int pop3c_mail_get_save_date(struct mail *_mail, time_t *date_r)
+{
+	struct index_mail *mail = INDEX_MAIL(_mail);
+	struct index_mail_data *data = &mail->data;
+
+	if (data->save_date == (time_t)-1) {
+		/* FIXME: we could use a value stored in cache */
+		if (pop3c_mail_get_received_date(_mail, date_r) < 0)
+			return -1;
+		return 0;
+	}
+	*date_r = data->save_date;
+	return 0;
+}
+
+static int pop3c_mail_get_physical_size(struct mail *_mail, uoff_t *size_r)
+{
+	struct index_mail *mail = INDEX_MAIL(_mail);
+	struct pop3c_mailbox *mbox = POP3C_MAILBOX(_mail->box);
+	struct message_size hdr_size, body_size;
+	struct istream *input;
+
+	if (mail->data.virtual_size != UOFF_T_MAX) {
+		/* virtual size is already known. it's the same as our
+		   (correct) physical size */
+		*size_r = mail->data.virtual_size;
+		return 0;
+	}
+	if (index_mail_get_physical_size(_mail, size_r) == 0) {
+		*size_r = mail->data.physical_size;
+		return 0;
+	}
+
+	if (_mail->lookup_abort == MAIL_LOOKUP_ABORT_READ_MAIL &&
+	    (_mail->box->flags & MAILBOX_FLAG_POP3_SESSION) != 0) {
+		/* kludge: we want output for POP3 LIST with
+		   pop3_fast_size_lookups=yes. use the remote's LIST values
+		   regardless of their correctness */
+		if (mbox->msg_sizes == NULL) {
+			if (pop3c_sync_get_sizes(mbox) < 0)
+				return -1;
+		}
+		i_assert(_mail->seq <= mbox->msg_count);
+		*size_r = mbox->msg_sizes[_mail->seq-1];
+		return 0;
+	}
+
+	/* slow way: get the whole message body */
+	if (mail_get_stream(_mail, &hdr_size, &body_size, &input) < 0)
+		return -1;
+
+	i_assert(mail->data.physical_size != UOFF_T_MAX);
+	*size_r = mail->data.physical_size;
+	return 0;
+}
+
+static void pop3c_mail_cache_size(struct index_mail *mail)
+{
+	uoff_t size;
+
+	if (i_stream_get_size(mail->data.stream, TRUE, &size) <= 0)
+		return;
+	mail->data.virtual_size = size;
+	/* it'll be actually added to index when closing the mail in
+	   index_mail_cache_sizes() */
+}
+
+static void
+pop3c_mail_prefetch_done(enum pop3c_command_state state,
+			 const char *reply ATTR_UNUSED, void *context)
+{
+	struct pop3c_mail *pmail = context;
+
+	switch (state) {
+	case POP3C_COMMAND_STATE_OK:
+		break;
+	case POP3C_COMMAND_STATE_ERR:
+	case POP3C_COMMAND_STATE_DISCONNECTED:
+		i_stream_unref(&pmail->prefetch_stream);
+		/* let pop3c_mail_get_stream() figure out the error handling.
+		   in case of a -ERR a retry might even work. */
+		break;
+	}
+	pmail->prefetching = FALSE;
+}
+
+static bool pop3c_mail_prefetch(struct mail *_mail)
+{
+	struct pop3c_mail *pmail = POP3C_MAIL(_mail);
+	struct pop3c_mailbox *mbox = POP3C_MAILBOX(_mail->box);
+	enum pop3c_capability capa;
+	const char *cmd;
+
+	if (pmail->imail.data.access_part != 0 &&
+	    pmail->imail.data.stream == NULL &&
+	    mail_stream_access_start(_mail)) {
+		capa = pop3c_client_get_capabilities(mbox->client);
+		pmail->prefetching_body = (capa & POP3C_CAPABILITY_TOP) == 0 ||
+			(pmail->imail.data.access_part & (READ_BODY | PARSE_BODY)) != 0;
+		if (pmail->prefetching_body)
+			cmd = t_strdup_printf("RETR %u\r\n", _mail->seq);
+		else
+			cmd = t_strdup_printf("TOP %u 0\r\n", _mail->seq);
+
+		pmail->prefetching = TRUE;
+		pmail->prefetch_stream =
+			pop3c_client_cmd_stream_async(mbox->client, cmd,
+				pop3c_mail_prefetch_done, pmail);
+		i_stream_set_name(pmail->prefetch_stream, t_strcut(cmd, '\r'));
+		return !pmail->prefetching;
+	}
+	return index_mail_prefetch(_mail);
+}
+
+static int
+pop3c_mail_get_stream(struct mail *_mail, bool get_body,
+		      struct message_size *hdr_size,
+		      struct message_size *body_size, struct istream **stream_r)
+{
+	struct pop3c_mail *pmail = POP3C_MAIL(_mail);
+	struct index_mail *mail = &pmail->imail;
+	struct pop3c_mailbox *mbox = POP3C_MAILBOX(_mail->box);
+	enum pop3c_capability capa;
+	const char *name, *cmd, *error;
+	struct istream *input;
+	bool new_stream = FALSE;
+
+	if ((mail->data.access_part & (READ_BODY | PARSE_BODY)) != 0)
+		get_body = TRUE;
+
+	while (pmail->prefetching) {
+		/* wait for prefetch to finish */
+		pop3c_client_wait_one(mbox->client);
+	}
+
+	if (pmail->prefetch_stream != NULL && mail->data.stream == NULL) {
+		mail->data.stream = pmail->prefetch_stream;
+		pmail->prefetch_stream = NULL;
+		new_stream = TRUE;
+	}
+
+	if (get_body && mail->data.stream != NULL) {
+		name = i_stream_get_name(mail->data.stream);
+		if (str_begins(name, "RETR")) {
+			/* we've fetched the body */
+		} else if (str_begins(name, "TOP")) {
+			/* we've fetched the header, but we need the body
+			   now too */
+			index_mail_close_streams(mail);
+		} else {
+			i_panic("Unexpected POP3 stream name: %s", name);
+		}
+	}
+
+	if (mail->data.stream == NULL) {
+		if (!mail_stream_access_start(_mail))
+			return -1;
+		capa = pop3c_client_get_capabilities(mbox->client);
+		if (get_body || (capa & POP3C_CAPABILITY_TOP) == 0) {
+			cmd = t_strdup_printf("RETR %u\r\n", _mail->seq);
+			get_body = TRUE;
+		} else {
+			cmd = t_strdup_printf("TOP %u 0\r\n", _mail->seq);
+		}
+		if (pop3c_client_cmd_stream(mbox->client, cmd,
+					    &input, &error) < 0) {
+			mail_storage_set_error(mbox->box.storage,
+				!pop3c_client_is_connected(mbox->client) ?
+				MAIL_ERROR_TEMP : MAIL_ERROR_EXPUNGED, error);
+			return -1;
+		}
+		mail->data.stream = input;
+		i_stream_set_name(mail->data.stream, t_strcut(cmd, '\r'));
+		new_stream = TRUE;
+	}
+	if (new_stream) {
+		if (mail->mail.v.istream_opened != NULL) {
+			if (mail->mail.v.istream_opened(_mail,
+							&mail->data.stream) < 0) {
+				index_mail_close_streams(mail);
+				return -1;
+			}
+		}
+		if (get_body)
+			pop3c_mail_cache_size(mail);
+	}
+	/* if this stream is used by some filter stream, make the
+	   filter stream blocking */
+	mail->data.stream->blocking = TRUE;
+	return index_mail_init_stream(mail, hdr_size, body_size, stream_r);
+}
+
+static int
+pop3c_mail_get_special(struct mail *_mail, enum mail_fetch_field field,
+		       const char **value_r)
+{
+	struct pop3c_mailbox *mbox = POP3C_MAILBOX(_mail->box);
+
+	switch (field) {
+	case MAIL_FETCH_UIDL_BACKEND:
+	case MAIL_FETCH_GUID:
+		if (mbox->msg_uidls == NULL) {
+			if (pop3c_sync_get_uidls(mbox) < 0)
+				return -1;
+		}
+		i_assert(_mail->seq <= mbox->msg_count);
+		*value_r = mbox->msg_uidls[_mail->seq-1];
+		return 0;
+	default:
+		return index_mail_get_special(_mail, field, value_r);
+	}
+}
+
+struct mail_vfuncs pop3c_mail_vfuncs = {
+	pop3c_mail_close,
+	index_mail_free,
+	index_mail_set_seq,
+	index_mail_set_uid,
+	index_mail_set_uid_cache_updates,
+	pop3c_mail_prefetch,
+	index_mail_precache,
+	index_mail_add_temp_wanted_fields,
+
+	index_mail_get_flags,
+	index_mail_get_keywords,
+	index_mail_get_keyword_indexes,
+	index_mail_get_modseq,
+	index_mail_get_pvt_modseq,
+	index_mail_get_parts,
+	index_mail_get_date,
+	pop3c_mail_get_received_date,
+	pop3c_mail_get_save_date,
+	index_mail_get_virtual_size,
+	pop3c_mail_get_physical_size,
+	index_mail_get_first_header,
+	index_mail_get_headers,
+	index_mail_get_header_stream,
+	pop3c_mail_get_stream,
+	index_mail_get_binary_stream,
+	pop3c_mail_get_special,
+	index_mail_get_backend_mail,
+	index_mail_update_flags,
+	index_mail_update_keywords,
+	index_mail_update_modseq,
+	index_mail_update_pvt_modseq,
+	NULL,
+	index_mail_expunge,
+	index_mail_set_cache_corrupted,
+	index_mail_opened,
+};
diff --git a/src/lib-storage/index/pop3c/pop3c-settings.c b/src/lib-storage/index/pop3c/pop3c-settings.c
new file mode 100644
index 0000000..db876e1
--- /dev/null
+++ b/src/lib-storage/index/pop3c/pop3c-settings.c
@@ -0,0 +1,116 @@
+/* Copyright (c) 2011-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "settings-parser.h"
+#include "mail-storage-settings.h"
+#include "pop3c-settings.h"
+
+#include <stddef.h>
+
+#undef DEF
+#define DEF(type, name) \
+	SETTING_DEFINE_STRUCT_##type(#name, name, struct pop3c_settings)
+
+static const struct setting_define pop3c_setting_defines[] = {
+	DEF(STR, pop3c_host),
+	DEF(IN_PORT, pop3c_port),
+
+	DEF(STR_VARS, pop3c_user),
+	DEF(STR_VARS, pop3c_master_user),
+	DEF(STR, pop3c_password),
+
+	DEF(ENUM, pop3c_ssl),
+	DEF(BOOL, pop3c_ssl_verify),
+
+	DEF(STR, pop3c_rawlog_dir),
+	DEF(BOOL, pop3c_quick_received_date),
+
+	DEF(STR, pop3c_features),
+
+	SETTING_DEFINE_LIST_END
+};
+
+static const struct pop3c_settings pop3c_default_settings = {
+	.pop3c_host = "",
+	.pop3c_port = 110,
+
+	.pop3c_user = "%u",
+	.pop3c_master_user = "",
+	.pop3c_password = "",
+
+	.pop3c_ssl = "no:pop3s:starttls",
+	.pop3c_ssl_verify = TRUE,
+
+	.pop3c_rawlog_dir = "",
+	.pop3c_quick_received_date = FALSE,
+
+	.pop3c_features = ""
+};
+
+/* <settings checks> */
+struct pop3c_feature_list {
+	const char *name;
+	enum pop3c_features num;
+};
+
+static const struct pop3c_feature_list pop3c_feature_list[] = {
+	{ "no-pipelining", POP3C_FEATURE_NO_PIPELINING },
+	{ NULL, 0 }
+};
+
+static int
+pop3c_settings_parse_features(struct pop3c_settings *set,
+			      const char **error_r)
+{
+	enum pop3c_features features = 0;
+	const struct pop3c_feature_list *list;
+	const char *const *str;
+
+	str = t_strsplit_spaces(set->pop3c_features, " ,");
+	for (; *str != NULL; str++) {
+		list = pop3c_feature_list;
+		for (; list->name != NULL; list++) {
+			if (strcasecmp(*str, list->name) == 0) {
+				features |= list->num;
+				break;
+			}
+		}
+		if (list->name == NULL) {
+			*error_r = t_strdup_printf("pop3c_features: "
+				"Unknown feature: %s", *str);
+			return -1;
+		}
+	}
+	set->parsed_features = features;
+	return 0;
+}
+
+static bool pop3c_settings_check(void *_set, pool_t pool ATTR_UNUSED,
+				 const char **error_r)
+{
+	struct pop3c_settings *set = _set;
+
+	if (pop3c_settings_parse_features(set, error_r) < 0)
+		return FALSE;
+	return TRUE;
+}
+/* </settings checks> */
+
+static const struct setting_parser_info pop3c_setting_parser_info = {
+	.module_name = "pop3c",
+	.defines = pop3c_setting_defines,
+	.defaults = &pop3c_default_settings,
+
+	.type_offset = SIZE_MAX,
+	.struct_size = sizeof(struct pop3c_settings),
+
+	.parent_offset = SIZE_MAX,
+	.parent = &mail_user_setting_parser_info,
+
+        .check_func = pop3c_settings_check
+};
+
+const struct setting_parser_info *pop3c_get_setting_parser_info(void)
+{
+	return &pop3c_setting_parser_info;
+}
diff --git a/src/lib-storage/index/pop3c/pop3c-settings.h b/src/lib-storage/index/pop3c/pop3c-settings.h
new file mode 100644
index 0000000..bf44e24
--- /dev/null
+++ b/src/lib-storage/index/pop3c/pop3c-settings.h
@@ -0,0 +1,33 @@
+#ifndef POP3C_SETTINGS_H
+#define POP3C_SETTINGS_H
+
+#include "net.h"
+
+/* <settings checks> */
+enum pop3c_features {
+        POP3C_FEATURE_NO_PIPELINING = 0x1,
+};
+/* </settings checks> */
+
+
+struct pop3c_settings {
+	const char *pop3c_host;
+	in_port_t pop3c_port;
+
+	const char *pop3c_user;
+	const char *pop3c_master_user;
+	const char *pop3c_password;
+
+	const char *pop3c_ssl;
+	bool pop3c_ssl_verify;
+
+	const char *pop3c_rawlog_dir;
+	bool pop3c_quick_received_date;
+
+	const char *pop3c_features;
+	enum pop3c_features parsed_features;
+};
+
+const struct setting_parser_info *pop3c_get_setting_parser_info(void);
+
+#endif
diff --git a/src/lib-storage/index/pop3c/pop3c-storage.c b/src/lib-storage/index/pop3c/pop3c-storage.c
new file mode 100644
index 0000000..f784683
--- /dev/null
+++ b/src/lib-storage/index/pop3c/pop3c-storage.c
@@ -0,0 +1,368 @@
+/* Copyright (c) 2011-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "ioloop.h"
+#include "str.h"
+#include "mail-copy.h"
+#include "mail-user.h"
+#include "mailbox-list-private.h"
+#include "index-mail.h"
+#include "pop3c-client.h"
+#include "pop3c-sync.h"
+#include "pop3c-storage.h"
+
+#define DNS_CLIENT_SOCKET_NAME "dns-client"
+
+extern struct mail_storage pop3c_storage;
+extern struct mailbox pop3c_mailbox;
+
+static struct event_category event_category_pop3c = {
+	.name = "pop3c",
+	.parent = &event_category_storage,
+};
+
+static struct mail_storage *pop3c_storage_alloc(void)
+{
+	struct pop3c_storage *storage;
+	pool_t pool;
+
+	pool = pool_alloconly_create("pop3c storage", 512+256);
+	storage = p_new(pool, struct pop3c_storage, 1);
+	storage->storage = pop3c_storage;
+	storage->storage.pool = pool;
+	return &storage->storage;
+}
+
+static int
+pop3c_storage_create(struct mail_storage *_storage,
+		     struct mail_namespace *ns,
+		     const char **error_r)
+{
+	struct pop3c_storage *storage = POP3C_STORAGE(_storage);
+
+	storage->set = mail_namespace_get_driver_settings(ns, _storage);
+	if (storage->set->pop3c_host[0] == '\0') {
+		*error_r = "missing pop3c_host";
+		return -1;
+	}
+	if (storage->set->pop3c_password[0] == '\0') {
+		*error_r = "missing pop3c_password";
+		return -1;
+	}
+
+	return 0;
+}
+
+static struct pop3c_client *
+pop3c_client_create_from_set(struct mail_storage *storage,
+			     const struct pop3c_settings *set)
+{
+	struct pop3c_client_settings client_set;
+	string_t *str;
+
+	i_zero(&client_set);
+	client_set.host = set->pop3c_host;
+	client_set.port = set->pop3c_port;
+	client_set.username = set->pop3c_user;
+	client_set.master_user = set->pop3c_master_user;
+	client_set.password = set->pop3c_password;
+	client_set.dns_client_socket_path =
+		storage->user->set->base_dir[0] == '\0' ? "" :
+		t_strconcat(storage->user->set->base_dir, "/",
+			    DNS_CLIENT_SOCKET_NAME, NULL);
+	str = t_str_new(128);
+	mail_user_set_get_temp_prefix(str, storage->user->set);
+	client_set.temp_path_prefix = str_c(str);
+
+	client_set.debug = storage->user->mail_debug;
+	client_set.rawlog_dir =
+		mail_user_home_expand(storage->user, set->pop3c_rawlog_dir);
+
+	mail_user_init_ssl_client_settings(storage->user, &client_set.ssl_set);
+
+	if (!set->pop3c_ssl_verify)
+		client_set.ssl_set.allow_invalid_cert = TRUE;
+
+	if (strcmp(set->pop3c_ssl, "pop3s") == 0)
+		client_set.ssl_mode = POP3C_CLIENT_SSL_MODE_IMMEDIATE;
+	else if (strcmp(set->pop3c_ssl, "starttls") == 0)
+		client_set.ssl_mode = POP3C_CLIENT_SSL_MODE_STARTTLS;
+	else
+		client_set.ssl_mode = POP3C_CLIENT_SSL_MODE_NONE;
+	return pop3c_client_init(&client_set, storage->event);
+}
+
+static void
+pop3c_storage_get_list_settings(const struct mail_namespace *ns ATTR_UNUSED,
+				struct mailbox_list_settings *set)
+{
+	set->layout = MAILBOX_LIST_NAME_FS;
+	if (set->root_dir != NULL && *set->root_dir != '\0' &&
+	    set->index_dir == NULL) {
+	       /* we don't really care about root_dir, but we
+		  just need to get index_dir autocreated. */
+		set->index_dir = set->root_dir;
+	}
+}
+
+static struct mailbox *
+pop3c_mailbox_alloc(struct mail_storage *storage, struct mailbox_list *list,
+		    const char *vname, enum mailbox_flags flags)
+{
+	struct pop3c_mailbox *mbox;
+	pool_t pool;
+
+	pool = pool_alloconly_create("pop3c mailbox", 1024*3);
+	mbox = p_new(pool, struct pop3c_mailbox, 1);
+	mbox->box = pop3c_mailbox;
+	mbox->box.pool = pool;
+	mbox->box.storage = storage;
+	mbox->box.list = list;
+	mbox->box.list->props |= MAILBOX_LIST_PROP_AUTOCREATE_DIRS;
+	mbox->box.mail_vfuncs = &pop3c_mail_vfuncs;
+	mbox->storage = POP3C_STORAGE(storage);
+
+	index_storage_mailbox_alloc(&mbox->box, vname, flags, MAIL_INDEX_PREFIX);
+	return &mbox->box;
+}
+
+static int
+pop3c_mailbox_exists(struct mailbox *box, bool auto_boxes,
+		     enum mailbox_existence *existence_r)
+{
+	if ((auto_boxes && mailbox_is_autocreated(box)) || box->inbox_any)
+		*existence_r = MAILBOX_EXISTENCE_SELECT;
+	else
+		*existence_r = MAILBOX_EXISTENCE_NONE;
+	return 0;
+}
+
+static void pop3c_login_callback(enum pop3c_command_state state,
+				 const char *reply, void *context)
+{
+	struct pop3c_mailbox *mbox = context;
+
+	switch (state) {
+	case POP3C_COMMAND_STATE_OK:
+		mbox->logged_in = TRUE;
+		break;
+	case POP3C_COMMAND_STATE_ERR:
+		if (str_begins(reply, "[IN-USE] ")) {
+			mail_storage_set_error(mbox->box.storage,
+					       MAIL_ERROR_INUSE, reply + 9);
+		} else {
+			/* authentication failure probably */
+			mail_storage_set_error(mbox->box.storage,
+					       MAIL_ERROR_PARAMS, reply);
+		}
+		break;
+	case POP3C_COMMAND_STATE_DISCONNECTED:
+		mailbox_set_critical(&mbox->box,
+			"pop3c: Disconnected from remote server");
+		break;
+	}
+}
+
+static int pop3c_mailbox_open(struct mailbox *box)
+{
+	struct pop3c_mailbox *mbox = POP3C_MAILBOX(box);
+
+	if (strcmp(box->name, "INBOX") != 0) {
+		mail_storage_set_error(box->storage, MAIL_ERROR_NOTFOUND,
+				       T_MAIL_ERR_MAILBOX_NOT_FOUND(box->vname));
+		return -1;
+	}
+
+	if (index_storage_mailbox_open(box, FALSE) < 0)
+		return -1;
+
+	mbox->client = pop3c_client_create_from_set(box->storage,
+						    mbox->storage->set);
+	pop3c_client_login(mbox->client, pop3c_login_callback, mbox);
+	pop3c_client_wait_one(mbox->client);
+	return mbox->logged_in ? 0 : -1;
+}
+
+static void pop3c_mailbox_close(struct mailbox *box)
+{
+	struct pop3c_mailbox *mbox = POP3C_MAILBOX(box);
+
+	pool_unref(&mbox->uidl_pool);
+	i_free_and_null(mbox->msg_uids);
+	i_free_and_null(mbox->msg_sizes);
+	pop3c_client_deinit(&mbox->client);
+	index_storage_mailbox_close(box);
+}
+
+static int
+pop3c_mailbox_create(struct mailbox *box,
+		     const struct mailbox_update *update ATTR_UNUSED,
+		     bool directory ATTR_UNUSED)
+{
+	mail_storage_set_error(box->storage, MAIL_ERROR_NOTPOSSIBLE,
+			       "POP3 mailbox creation isn't supported");
+	return -1;
+}
+
+static int
+pop3c_mailbox_update(struct mailbox *box,
+		     const struct mailbox_update *update ATTR_UNUSED)
+{
+	if (!guid_128_is_empty(update->mailbox_guid) ||
+	    update->uid_validity != 0 || update->min_next_uid != 0 ||
+	    update->min_first_recent_uid != 0) {
+		mail_storage_set_error(box->storage, MAIL_ERROR_NOTPOSSIBLE,
+				       "POP3 mailbox update isn't supported");
+	}
+	return index_storage_mailbox_update(box, update);
+}
+
+static int pop3c_mailbox_get_status(struct mailbox *box,
+				    enum mailbox_status_items items,
+				    struct mailbox_status *status_r)
+{
+	struct pop3c_mailbox *mbox = POP3C_MAILBOX(box);
+
+	if (index_storage_get_status(box, items, status_r) < 0)
+		return -1;
+
+	if ((pop3c_client_get_capabilities(mbox->client) &
+	     POP3C_CAPABILITY_UIDL) == 0)
+		status_r->have_guids = FALSE;
+	return 0;
+}
+
+static int pop3c_mailbox_get_metadata(struct mailbox *box,
+				      enum mailbox_metadata_items items,
+				      struct mailbox_metadata *metadata_r)
+{
+	if ((items & MAILBOX_METADATA_GUID) != 0) {
+		/* a bit ugly way to do this, but better than nothing for now.
+		   FIXME: if indexes are enabled, keep this there. */
+		mail_generate_guid_128_hash(box->name, metadata_r->guid);
+		items &= ENUM_NEGATE(MAILBOX_METADATA_GUID);
+	}
+	if (items != 0) {
+		if (index_mailbox_get_metadata(box, items, metadata_r) < 0)
+			return -1;
+	}
+	return 0;
+}
+
+static void pop3c_notify_changes(struct mailbox *box ATTR_UNUSED)
+{
+}
+
+static struct mail_save_context *
+pop3c_save_alloc(struct mailbox_transaction_context *t)
+{
+	struct mail_save_context *ctx;
+
+	ctx = i_new(struct mail_save_context, 1);
+	ctx->transaction = t;
+	return ctx;
+}
+
+static int
+pop3c_save_begin(struct mail_save_context *ctx,
+		 struct istream *input ATTR_UNUSED)
+{
+	mail_storage_set_error(ctx->transaction->box->storage,
+		MAIL_ERROR_NOTPOSSIBLE, "POP3 doesn't support saving mails");
+	return -1;
+}
+
+static int pop3c_save_continue(struct mail_save_context *ctx ATTR_UNUSED)
+{
+	return -1;
+}
+
+static int pop3c_save_finish(struct mail_save_context *ctx)
+{
+	index_save_context_free(ctx);
+	return -1;
+}
+
+static void
+pop3c_save_cancel(struct mail_save_context *ctx)
+{
+	index_save_context_free(ctx);
+}
+
+static bool pop3c_storage_is_inconsistent(struct mailbox *box)
+{
+	struct pop3c_mailbox *mbox = POP3C_MAILBOX(box);
+
+	return index_storage_is_inconsistent(box) ||
+		!pop3c_client_is_connected(mbox->client);
+}
+
+struct mail_storage pop3c_storage = {
+	.name = POP3C_STORAGE_NAME,
+	.class_flags = MAIL_STORAGE_CLASS_FLAG_NO_ROOT |
+		MAIL_STORAGE_CLASS_FLAG_HAVE_MAIL_GUIDS,
+	.event_category = &event_category_pop3c,
+
+	.v = {
+		pop3c_get_setting_parser_info,
+		pop3c_storage_alloc,
+		pop3c_storage_create,
+		index_storage_destroy,
+		NULL,
+		pop3c_storage_get_list_settings,
+		NULL,
+		pop3c_mailbox_alloc,
+		NULL,
+		NULL,
+	}
+};
+
+struct mailbox pop3c_mailbox = {
+	.v = {
+		index_storage_is_readonly,
+		index_storage_mailbox_enable,
+		pop3c_mailbox_exists,
+		pop3c_mailbox_open,
+		pop3c_mailbox_close,
+		index_storage_mailbox_free,
+		pop3c_mailbox_create,
+		pop3c_mailbox_update,
+		index_storage_mailbox_delete,
+		index_storage_mailbox_rename,
+		pop3c_mailbox_get_status,
+		pop3c_mailbox_get_metadata,
+		index_storage_set_subscribed,
+		index_storage_attribute_set,
+		index_storage_attribute_get,
+		index_storage_attribute_iter_init,
+		index_storage_attribute_iter_next,
+		index_storage_attribute_iter_deinit,
+		index_storage_list_index_has_changed,
+		index_storage_list_index_update_sync,
+		pop3c_storage_sync_init,
+		index_mailbox_sync_next,
+		index_mailbox_sync_deinit,
+		NULL,
+		pop3c_notify_changes,
+		index_transaction_begin,
+		index_transaction_commit,
+		index_transaction_rollback,
+		NULL,
+		pop3c_mail_alloc,
+		index_storage_search_init,
+		index_storage_search_deinit,
+		index_storage_search_next_nonblock,
+		index_storage_search_next_update_seq,
+		index_storage_search_next_match_mail,
+		pop3c_save_alloc,
+		pop3c_save_begin,
+		pop3c_save_continue,
+		pop3c_save_finish,
+		pop3c_save_cancel,
+		mail_storage_copy,
+		NULL,
+		NULL,
+		NULL,
+		pop3c_storage_is_inconsistent
+	}
+};
diff --git a/src/lib-storage/index/pop3c/pop3c-storage.h b/src/lib-storage/index/pop3c/pop3c-storage.h
new file mode 100644
index 0000000..f271a59
--- /dev/null
+++ b/src/lib-storage/index/pop3c/pop3c-storage.h
@@ -0,0 +1,51 @@
+#ifndef POP3C_STORAGE_H
+#define POP3C_STORAGE_H
+
+#include "index-storage.h"
+
+#define POP3C_STORAGE_NAME "pop3c"
+
+struct pop3c_storage {
+	struct mail_storage storage;
+	const struct pop3c_settings *set;
+};
+
+struct pop3c_mailbox {
+	struct mailbox box;
+	struct pop3c_storage *storage;
+
+	struct pop3c_client *client;
+
+	pool_t uidl_pool;
+	unsigned int msg_count;
+	/* LIST sizes */
+	uoff_t *msg_sizes;
+	/* UIDL strings */
+	const char *const *msg_uidls;
+	/* index UIDs for each message in this session.
+	   the UID may not exist for the entire session */
+	uint32_t *msg_uids;
+
+	bool logged_in:1;
+};
+
+struct pop3c_mail {
+	struct index_mail imail;
+	struct istream *prefetch_stream;
+
+	bool prefetching:1;
+	bool prefetching_body:1;
+};
+
+#define POP3C_STORAGE(s)	container_of(s, struct pop3c_storage, storage)
+#define POP3C_MAILBOX(s)	container_of(s, struct pop3c_mailbox, box)
+#define POP3C_MAIL(s)		container_of(s, struct pop3c_mail, imail.mail.mail)
+
+struct mail *
+pop3c_mail_alloc(struct mailbox_transaction_context *t,
+		 enum mail_fetch_field wanted_fields,
+		 struct mailbox_header_lookup_ctx *wanted_headers);
+
+extern struct mail_vfuncs pop3c_mail_vfuncs;
+
+#endif
diff --git a/src/lib-storage/index/pop3c/pop3c-sync.c b/src/lib-storage/index/pop3c/pop3c-sync.c
new file mode 100644
index 0000000..2d2dbe3
--- /dev/null
+++ b/src/lib-storage/index/pop3c/pop3c-sync.c
@@ -0,0 +1,361 @@
+/* Copyright (c) 2011-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "ioloop.h"
+#include "istream.h"
+#include "bsearch-insert-pos.h"
+#include "str.h"
+#include "sort.h"
+#include "strnum.h"
+#include "index-mail.h"
+#include "pop3c-client.h"
+#include "pop3c-storage.h"
+#include "pop3c-sync.h"
+#include "mailbox-recent-flags.h"
+
+struct pop3c_sync_msg {
+	uint32_t seq;
+	const char *uidl;
+};
+ARRAY_DEFINE_TYPE(pop3c_sync_msg, struct pop3c_sync_msg);
+
+int pop3c_sync_get_uidls(struct pop3c_mailbox *mbox)
+{
+	ARRAY_TYPE(const_string) uidls;
+	struct istream *input;
+	const char *error, *cline;
+	char *line, *p;
+	unsigned int seq, line_seq;
+
+	if (mbox->msg_uidls != NULL)
+		return 0;
+	if ((pop3c_client_get_capabilities(mbox->client) &
+	     POP3C_CAPABILITY_UIDL) == 0) {
+		mail_storage_set_error(mbox->box.storage,
+				       MAIL_ERROR_NOTPOSSIBLE,
+				       "UIDLs not supported by server");
+		return -1;
+	}
+
+	if (pop3c_client_cmd_stream(mbox->client, "UIDL\r\n",
+				    &input, &error) < 0) {
+		mailbox_set_critical(&mbox->box, "UIDL failed: %s", error);
+		return -1;
+	}
+
+	mbox->uidl_pool = pool_alloconly_create("POP3 UIDLs", 1024*32);
+	p_array_init(&uidls, mbox->uidl_pool, 64); seq = 0;
+	while ((line = i_stream_read_next_line(input)) != NULL) {
+		seq++;
+		p = strchr(line, ' ');
+		if (p == NULL) {
+			mailbox_set_critical(&mbox->box,
+				"Invalid UIDL line: %s", line);
+			break;
+		}
+		*p++ = '\0';
+		if (str_to_uint(line, &line_seq) < 0 || line_seq != seq) {
+			mailbox_set_critical(&mbox->box,
+				"Unexpected UIDL seq: %s != %u", line, seq);
+			break;
+		}
+
+		cline = p_strdup(mbox->uidl_pool, p);
+		array_push_back(&uidls, &cline);
+	}
+	i_stream_destroy(&input);
+	if (line != NULL) {
+		pool_unref(&mbox->uidl_pool);
+		return -1;
+	}
+	if (seq == 0) {
+		/* make msg_uidls non-NULL */
+		array_append_zero(&uidls);
+	}
+	mbox->msg_uidls = array_front(&uidls);
+	mbox->msg_count = seq;
+	return 0;
+}
+
+int pop3c_sync_get_sizes(struct pop3c_mailbox *mbox)
+{
+	struct istream *input;
+	const char *error;
+	char *line, *p;
+	unsigned int seq, line_seq;
+
+	i_assert(mbox->msg_sizes == NULL);
+
+	if (mbox->msg_uidls == NULL) {
+		if (pop3c_sync_get_uidls(mbox) < 0)
+			return -1;
+	}
+	if (mbox->msg_count == 0) {
+		mbox->msg_sizes = i_new(uoff_t, 1);
+		return 0;
+	}
+
+	if (pop3c_client_cmd_stream(mbox->client, "LIST\r\n",
+				    &input, &error) < 0) {
+		mailbox_set_critical(&mbox->box, "LIST failed: %s", error);
+		return -1;
+	}
+
+	mbox->msg_sizes = i_new(uoff_t, mbox->msg_count); seq = 0;
+	while ((line = i_stream_read_next_line(input)) != NULL) {
+		if (++seq > mbox->msg_count) {
+			mailbox_set_critical(&mbox->box,
+				"Too much data in LIST: %s", line);
+			break;
+		}
+		p = strchr(line, ' ');
+		if (p == NULL) {
+			mailbox_set_critical(&mbox->box,
+				"Invalid LIST line: %s", line);
+			break;
+		}
+		*p++ = '\0';
+		if (str_to_uint(line, &line_seq) < 0 || line_seq != seq) {
+			mailbox_set_critical(&mbox->box,
+				"Unexpected LIST seq: %s != %u", line, seq);
+			break;
+		}
+		if (str_to_uoff(p, &mbox->msg_sizes[seq-1]) < 0) {
+			mailbox_set_critical(&mbox->box,
+				"Invalid LIST size: %s", p);
+			break;
+		}
+	}
+	i_stream_destroy(&input);
+	if (line != NULL) {
+		i_free_and_null(mbox->msg_sizes);
+		return -1;
+	}
+	return 0;
+}
+
+static void
+pop3c_get_local_msgs(pool_t pool, ARRAY_TYPE(pop3c_sync_msg) *local_msgs,
+		     uint32_t messages_count,
+		     struct mail_cache_view *cache_view,
+		     unsigned int cache_idx)
+{
+	string_t *str = t_str_new(128);
+	struct pop3c_sync_msg msg;
+	uint32_t seq;
+
+	i_zero(&msg);
+	for (seq = 1; seq <= messages_count; seq++) {
+		str_truncate(str, 0);
+		if (mail_cache_lookup_field(cache_view, str, seq,
+					    cache_idx) > 0)
+			msg.uidl = p_strdup(pool, str_c(str));
+		msg.seq = seq;
+		array_idx_set(local_msgs, seq-1, &msg);
+	}
+}
+
+static void
+pop3c_get_remote_msgs(ARRAY_TYPE(pop3c_sync_msg) *remote_msgs,
+		      struct pop3c_mailbox *mbox)
+{
+	struct pop3c_sync_msg *msg;
+	uint32_t seq;
+
+	for (seq = 1; seq <= mbox->msg_count; seq++) {
+		msg = array_append_space(remote_msgs);
+		msg->seq = seq;
+		msg->uidl = mbox->msg_uidls[seq-1];
+	}
+}
+
+static int pop3c_sync_msg_uidl_cmp(const struct pop3c_sync_msg *msg1,
+				   const struct pop3c_sync_msg *msg2)
+{
+	return null_strcmp(msg1->uidl, msg2->uidl);
+}
+
+static void
+pop3c_sync_messages(struct pop3c_mailbox *mbox,
+		    struct mail_index_view *sync_view,
+		    struct mail_index_transaction *sync_trans,
+		    struct mail_cache_view *cache_view)
+{
+	struct index_mailbox_context *ibox =
+		INDEX_STORAGE_CONTEXT(&mbox->box);
+	const struct mail_index_header *hdr;
+	struct mail_cache_transaction_ctx *cache_trans;
+	ARRAY_TYPE(pop3c_sync_msg) local_msgs, remote_msgs;
+	const struct pop3c_sync_msg *lmsg, *rmsg;
+	uint32_t seq1, seq2, next_uid;
+	unsigned int lidx, ridx, lcount, rcount;
+	unsigned int cache_idx = ibox->cache_fields[MAIL_CACHE_POP3_UIDL].idx;
+	pool_t pool;
+
+	i_assert(mbox->msg_uids == NULL);
+
+	/* set our uidvalidity */
+	hdr = mail_index_get_header(sync_view);
+	if (hdr->uid_validity == 0) {
+		uint32_t uid_validity = ioloop_time;
+		mail_index_update_header(sync_trans,
+			offsetof(struct mail_index_header, uid_validity),
+			&uid_validity, sizeof(uid_validity), TRUE);
+	}
+
+	pool = pool_alloconly_create(MEMPOOL_GROWING"pop3c sync", 10240);
+	p_array_init(&local_msgs, pool, hdr->messages_count);
+	pop3c_get_local_msgs(pool, &local_msgs, hdr->messages_count,
+			     cache_view, cache_idx);
+	p_array_init(&remote_msgs, pool, mbox->msg_count);
+	pop3c_get_remote_msgs(&remote_msgs, mbox);
+
+	/* sort the messages by UIDLs, because some servers reorder messages */
+	array_sort(&local_msgs, pop3c_sync_msg_uidl_cmp);
+	array_sort(&remote_msgs, pop3c_sync_msg_uidl_cmp);
+
+	/* skip over existing messages with matching UIDLs and expunge the ones
+	   that no longer exist in remote. */
+	mbox->msg_uids = mbox->msg_count == 0 ?
+		i_new(uint32_t, 1) : /* avoid malloc(0) assert */
+		i_new(uint32_t, mbox->msg_count);
+	cache_trans = mail_cache_get_transaction(cache_view, sync_trans);
+
+	lmsg = array_get(&local_msgs, &lcount);
+	rmsg = array_get(&remote_msgs, &rcount);
+	next_uid = hdr->next_uid;
+	lidx = ridx = 0;
+	while (lidx < lcount || ridx < rcount) {
+		uint32_t lseq = lidx < lcount ? lmsg[lidx].seq : 0;
+		uint32_t rseq = ridx < rcount ? rmsg[ridx].seq : 0;
+		int ret;
+
+		if (lidx >= lcount)
+			ret = 1;
+		else if (ridx >= rcount || lmsg[lidx].uidl == NULL)
+			ret = -1;
+		else
+			ret = strcmp(lmsg[lidx].uidl, rmsg[ridx].uidl);
+		if (ret < 0) {
+			/* message expunged in remote, or we didn't have a
+			   local message's UIDL in cache. */
+			mail_index_expunge(sync_trans, lseq);
+			lidx++;
+		} else if (ret > 0) {
+			/* new message in remote */
+			i_assert(mbox->msg_uids[rseq-1] == 0);
+			mbox->msg_uids[rseq-1] = next_uid;
+			mail_index_append(sync_trans, next_uid++, &lseq);
+			mail_cache_add(cache_trans, lseq, cache_idx,
+				       rmsg[ridx].uidl,
+				       strlen(rmsg[ridx].uidl));
+			ridx++;
+		} else {
+			/* UIDL matched */
+			i_assert(mbox->msg_uids[rseq-1] == 0);
+			mail_index_lookup_uid(sync_view, lseq,
+					      &mbox->msg_uids[rseq-1]);
+			lidx++;
+			ridx++;
+		}
+	}
+
+	/* mark the newly seen messages as recent */
+	if (mail_index_lookup_seq_range(sync_view, hdr->first_recent_uid,
+					hdr->next_uid, &seq1, &seq2))
+		mailbox_recent_flags_set_seqs(&mbox->box, sync_view, seq1, seq2);
+	pool_unref(&pool);
+}
+
+int pop3c_sync(struct pop3c_mailbox *mbox)
+{
+        struct mail_index_sync_ctx *index_sync_ctx;
+	struct mail_index_view *sync_view, *trans_view;
+	struct mail_index_transaction *sync_trans;
+	struct mail_index_sync_rec sync_rec;
+	struct mail_cache_view *cache_view = NULL;
+	enum mail_index_sync_flags sync_flags;
+	unsigned int idx;
+	string_t *str;
+	const char *reply;
+	int ret;
+	bool deletions = FALSE;
+
+	if (pop3c_sync_get_uidls(mbox) < 0)
+		return -1;
+
+	sync_flags = index_storage_get_sync_flags(&mbox->box) |
+		MAIL_INDEX_SYNC_FLAG_FLUSH_DIRTY;
+
+	ret = mail_index_sync_begin(mbox->box.index, &index_sync_ctx,
+				    &sync_view, &sync_trans, sync_flags);
+	if (ret <= 0) {
+		if (ret < 0)
+			mailbox_set_index_error(&mbox->box);
+		return ret;
+	}
+
+	if (mbox->msg_uids == NULL) {
+		trans_view = mail_index_transaction_open_updated_view(sync_trans);
+		cache_view = mail_cache_view_open(mbox->box.cache, trans_view);
+		pop3c_sync_messages(mbox, sync_view, sync_trans, cache_view);
+	}
+
+	/* mark expunges messages as deleted in this pop3 session,
+	   if those exist */
+	str = t_str_new(32);
+	while (mail_index_sync_next(index_sync_ctx, &sync_rec)) {
+		if (sync_rec.type != MAIL_INDEX_SYNC_TYPE_EXPUNGE)
+			continue;
+
+		if (!bsearch_insert_pos(&sync_rec.uid1, mbox->msg_uids,
+					mbox->msg_count, sizeof(uint32_t),
+					uint32_cmp, &idx)) {
+			/* no such messages in this session */
+			continue;
+		}
+		for (; idx < mbox->msg_count; idx++) {
+			i_assert(mbox->msg_uids[idx] >= sync_rec.uid1);
+			if (mbox->msg_uids[idx] > sync_rec.uid2)
+				break;
+
+			str_truncate(str, 0);
+			str_printfa(str, "DELE %u\r\n", idx+1);
+			pop3c_client_cmd_line_async_nocb(mbox->client, str_c(str));
+			deletions = TRUE;
+		}
+	}
+
+	if (mail_index_sync_commit(&index_sync_ctx) < 0) {
+		mailbox_set_index_error(&mbox->box);
+		return -1;
+	}
+	if (cache_view != NULL) {
+		mail_cache_view_close(&cache_view);
+		mail_index_view_close(&trans_view);
+	}
+	if (deletions) {
+		if (pop3c_client_cmd_line(mbox->client, "QUIT\r\n",
+					  &reply) < 0) {
+			mail_storage_set_error(mbox->box.storage,
+					       MAIL_ERROR_TEMP, reply);
+			return -1;
+		}
+	}
+	return 0;
+}
+
+struct mailbox_sync_context *
+pop3c_storage_sync_init(struct mailbox *box, enum mailbox_sync_flags flags)
+{
+	struct pop3c_mailbox *mbox = POP3C_MAILBOX(box);
+	int ret = 0;
+
+	if ((flags & MAILBOX_SYNC_FLAG_FULL_READ) != 0 &&
+	    mbox->msg_uidls == NULL) {
+		/* FIXME: reconnect */
+	}
+
+	ret = pop3c_sync(mbox);
+	return index_mailbox_sync_init(box, flags, ret < 0);
+}
diff --git a/src/lib-storage/index/pop3c/pop3c-sync.h b/src/lib-storage/index/pop3c/pop3c-sync.h
new file mode 100644
index 0000000..bf3c802
--- /dev/null
+++ b/src/lib-storage/index/pop3c/pop3c-sync.h
@@ -0,0 +1,14 @@
+#ifndef POP3C_SYNC_H
+#define POP3C_SYNC_H
+
+struct mailbox;
+struct pop3c_mailbox;
+
+struct mailbox_sync_context *
+pop3c_storage_sync_init(struct mailbox *box, enum mailbox_sync_flags flags);
+int pop3c_sync(struct pop3c_mailbox *mbox);
+
+int pop3c_sync_get_sizes(struct pop3c_mailbox *mbox);
+int pop3c_sync_get_uidls(struct pop3c_mailbox *mbox);
+
+#endif