diff --git a/.cvsignore b/.cvsignore
index 8a8ea69..c4b8f01 100644
--- a/.cvsignore
+++ b/.cvsignore
@@ -25,3 +25,4 @@ haveuint128.h
 ent
 tags
 entities.h
+havepread.h
diff --git a/CHANGES b/CHANGES
index d0591bf..1938129 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,5 +1,6 @@
 0.31:
   special case buffer_get_token with token length 1 through memccpy (almost 4x speedup)
+  test for pread and use it instead of lseek+read in cdb and io_mmapwritefile
 
 0.30:
   add compiletimeassert.h
diff --git a/GNUmakefile b/GNUmakefile
index 10a2d96..574e3ed 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -133,6 +133,8 @@ dns_rcip.o dns_rcrw.o openreadclose.o: openreadclose.h
 
 iob_send.o scan_ip6if.o: havealloca.h
 
+cdb.o io_mmapwritefile.o: havepread.h
+
 # stoprip
 
 byte.a: $(BYTE_OBJS)
@@ -194,7 +196,7 @@ clean:
 	rm -f *.o *.a *.da *.bbg *.bb core t haveip6.h haven2i.h \
 havesl.h haveinline.h iopause.h select.h havekqueue.h haveepoll.h \
 libepoll havesigio.h havebsdsf.h havesendfile.h havescope.h havedevpoll.h \
-dep libsocket havealloca.h haveuint128.h entities.h ent
+dep libsocket havealloca.h haveuint128.h entities.h ent havepread.h
 
 INCLUDES=buffer.h byte.h fmt.h ip4.h ip6.h mmap.h scan.h socket.h str.h stralloc.h \
 uint16.h uint32.h uint64.h open.h textcode.h tai.h taia.h dns.h iopause.h case.h \
@@ -302,6 +304,11 @@ haveuint128.h: tryuint128.c
 	if $(DIET) $(CCC) $(CFLAGS) -c tryuint128.c >/dev/null 2>&1; then echo "#define HAVE_UINT128"; fi > $@
 	-rm -f tryuint128.o
 
+havepread.h: trypread.c
+	-rm -f $@
+	if $(DIET) $(CCC) $(CFLAGS) -c trypread.c >/dev/null 2>&1; then echo "#define HAVE_PREAD"; fi > $@
+	-rm -f trypread.o
+
 iopause.h: iopause.h1 iopause.h2 trypoll.c
 	-rm -f $@
 	if $(DIET) $(CCC) $(CFLAGS) -o t trypoll.c >/dev/null 2>&1; then cp iopause.h2 iopause.h; else cp iopause.h1 iopause.h; fi
diff --git a/Makefile b/Makefile
index fdf9a77..c910d2a 100644
--- a/Makefile
+++ b/Makefile
@@ -146,7 +146,7 @@ case_diffs.o: case/case_diffs.c case.h
 case_lowerb.o: case/case_lowerb.c case.h
 case_lowers.o: case/case_lowers.c case.h
 case_starts.o: case/case_starts.c case.h
-cdb.o: cdb/cdb.c byte.h cdb.h uint32.h uint64.h
+cdb.o: cdb/cdb.c byte.h cdb.h uint32.h uint64.h havepread.h
 cdb_hash.o: cdb/cdb_hash.c cdb.h uint32.h uint64.h
 cdb_make.o: cdb/cdb_make.c cdb.h uint32.h uint64.h cdb_make.h buffer.h
 cdb_traverse.o: cdb/cdb_traverse.c cdb.h uint32.h uint64.h
@@ -299,7 +299,7 @@ io_getcookie.o: io/io_getcookie.c io_internal.h io.h uint64.h taia.h \
  havesigio.h
 io_mmapwritefile.o: io/io_mmapwritefile.c io_internal.h io.h uint64.h \
  taia.h tai.h uint32.h array.h iarray.h haveepoll.h havekqueue.h \
- havedevpoll.h havesigio.h iob.h
+ havedevpoll.h havesigio.h iob.h havepread.h
 io_nonblock.o: io/io_nonblock.c io_internal.h io.h uint64.h taia.h tai.h \
  uint32.h array.h iarray.h haveepoll.h havekqueue.h havedevpoll.h \
  havesigio.h
@@ -702,8 +702,8 @@ t.o: t.c fmt.h byte.h scan.h str.h uint16.h uint32.h stralloc.h socket.h \
  critbit.h CAS.h io_internal.h haveepoll.h havekqueue.h havedevpoll.h \
  havesigio.h
 BYTE_OBJS=byte_chr.o byte_copy.o byte_copyr.o byte_diff.o byte_equal_notimingattack.o byte_rchr.o byte_zero.o 
-FMT_OBJS=fmt_8long.o fmt_8longlong.o fmt_asn1derlength.o fmt_asn1dertag.o fmt_double.o fmt_escapecharc.o fmt_escapecharhtml.o fmt_escapecharjson.o fmt_escapecharquotedprintable.o fmt_escapecharquotedprintableutf8.o fmt_escapecharxml.o fmt_fill.o fmt_httpdate.o fmt_human.o fmt_humank.o fmt_long.o fmt_longlong.o fmt_minus.o fmt_pad.o fmt_plusminus.o fmt_str.o fmt_strm_internal.o fmt_strn.o fmt_tohex.o fmt_ulong.o fmt_ulong0.o fmt_ulonglong.o fmt_utf8.o fmt_xlong.o fmt_xlonglong.o fmt_xmlescape.o 
-SCAN_OBJS=scan_8int.o scan_8long.o scan_8longlong.o scan_8longn.o scan_8short.o scan_asn1derlength.o scan_asn1dertag.o scan_charsetnskip.o scan_double.o scan_fromhex.o scan_httpdate.o scan_int.o scan_long.o scan_longlong.o scan_longn.o scan_netstring.o scan_noncharsetnskip.o scan_nonwhitenskip.o scan_plusminus.o scan_short.o scan_uint.o scan_ulong.o scan_ulonglong.o scan_ulongn.o scan_ushort.o scan_utf8.o scan_whitenskip.o scan_xint.o scan_xlong.o scan_xlonglong.o scan_xlongn.o scan_xshort.o 
+FMT_OBJS=fmt_8long.o fmt_8longlong.o fmt_asn1derlength.o fmt_asn1dertag.o fmt_double.o fmt_escapecharc.o fmt_escapecharhtml.o fmt_escapecharjson.o fmt_escapecharquotedprintable.o fmt_escapecharquotedprintableutf8.o fmt_escapecharxml.o fmt_fill.o fmt_httpdate.o fmt_human.o fmt_humank.o fmt_iso8601.o fmt_long.o fmt_longlong.o fmt_minus.o fmt_netstring.o fmt_pad.o fmt_pb_double.o fmt_pb_float.o fmt_pb_int.o fmt_pb_sint.o fmt_pb_string.o fmt_pb_tag.o fmt_pb_type0_sint.o fmt_pb_type1_double.o fmt_pb_type1_fixed64.o fmt_pb_type2_string.o fmt_pb_type5_fixed32.o fmt_pb_type5_float.o fmt_plusminus.o fmt_str.o fmt_strm_internal.o fmt_strn.o fmt_tohex.o fmt_ulong.o fmt_ulong0.o fmt_ulonglong.o fmt_utf8.o fmt_varint.o fmt_xlong.o fmt_xlonglong.o fmt_xmlescape.o 
+SCAN_OBJS=scan_8int.o scan_8long.o scan_8longlong.o scan_8longn.o scan_8short.o scan_asn1derlength.o scan_asn1dertag.o scan_charsetnskip.o scan_double.o scan_fromhex.o scan_httpdate.o scan_int.o scan_iso8601.o scan_long.o scan_longlong.o scan_longn.o scan_netstring.o scan_noncharsetnskip.o scan_nonwhitenskip.o scan_pb_tag.o scan_pb_type0_sint.o scan_pb_type1_double.o scan_pb_type1_fixed64.o scan_pb_type2_stringlen.o scan_pb_type5_fixed32.o scan_pb_type5_float.o scan_plusminus.o scan_short.o scan_uint.o scan_ulong.o scan_ulonglong.o scan_ulongn.o scan_ushort.o scan_utf8.o scan_varint.o scan_whitenskip.o scan_xint.o scan_xlong.o scan_xlonglong.o scan_xlongn.o scan_xshort.o 
 STR_OBJS=str_chr.o str_copy.o str_diff.o str_diffn.o str_len.o str_rchr.o str_start.o 
 UINT_OBJS=uint16_pack.o uint16_pack_big.o uint16_read.o uint16_read_big.o uint16_unpack.o uint16_unpack_big.o uint32_pack.o uint32_pack_big.o uint32_read.o uint32_read_big.o uint32_unpack.o uint32_unpack_big.o uint64_pack.o uint64_pack_big.o uint64_read.o uint64_read_big.o uint64_unpack.o uint64_unpack_big.o 
 OPEN_OBJS=open_append.o open_excl.o open_read.o open_rw.o open_trunc.o open_write.o openreadclose.o readclose.o 
@@ -719,7 +719,7 @@ CASE_OBJS=case_diffb.o case_diffs.o case_lowerb.o case_lowers.o case_starts.o
 MULT_OBJS=imult16.o imult32.o imult64.o range_arrayinbuf.o range_str2inbuf.o range_str4inbuf.o range_strinbuf.o umult16.o umult32.o umult64.o 
 ARRAY_OBJS=array_allocate.o array_bytes.o array_cat.o array_cat0.o array_catb.o array_cate.o array_cats.o array_cats0.o array_equal.o array_fail.o array_get.o array_length.o array_reset.o array_start.o array_trunc.o array_truncate.o iarray_allocate.o iarray_free.o iarray_get.o iarray_init.o iarray_length.o 
 IO_OBJS=io_appendfile.o io_block.o io_canread.o io_canwrite.o io_check.o io_close.o io_closeonexec.o io_createfile.o io_debugstring.o io_dontwantread.o io_dontwantwrite.o io_eagain.o io_eagain_read.o io_eagain_write.o io_fd.o io_finishandshutdown.o io_getcookie.o io_mmapwritefile.o io_nonblock.o io_passfd.o io_pipe.o io_readfile.o io_readwritefile.o io_receivefd.o io_sendfile.o io_setcookie.o io_sigpipe.o io_socketpair.o io_timedout.o io_timeout.o io_timeouted.o io_tryread.o io_tryreadtimeout.o io_trywrite.o io_trywritetimeout.o io_wait.o io_waitread.o io_waituntil.o io_waituntil2.o io_waitwrite.o io_wantread.o io_wantwrite.o iob_addbuf.o iob_addbuf_free.o iob_addbuf_internal.o iob_addbuf_munmap.o iob_addfile.o iob_addfile_close.o iob_adds.o iob_adds_free.o iob_bytesleft.o iob_free.o iob_new.o iob_prefetch.o iob_reset.o iob_send.o iob_write.o 
-TEXTCODE_OBJS=base64.o fmt_base64.o fmt_cescape.o fmt_foldwhitespace.o fmt_hexdump.o fmt_html.o fmt_html_tagarg.o fmt_jsonescape.o fmt_ldapescape.o fmt_ldapescape2.o fmt_quotedprintable.o fmt_to_array.o fmt_to_sa.o fmt_tofrom_array.o fmt_urlencoded.o fmt_uuencoded.o fmt_xml.o fmt_yenc.o scan_base64.o scan_cescape.o scan_hexdump.o scan_html.o scan_jsonescape.o scan_ldapescape.o scan_quotedprintable.o scan_to_array.o scan_to_sa.o scan_tofrom_array.o scan_urlencoded.o scan_uuencoded.o scan_yenc.o 
+TEXTCODE_OBJS=base64.o base64url.o fmt_base64.o fmt_base64url.o fmt_cescape.o fmt_foldwhitespace.o fmt_hexdump.o fmt_html.o fmt_html_tagarg.o fmt_jsonescape.o fmt_ldapescape.o fmt_ldapescape2.o fmt_quotedprintable.o fmt_to_array.o fmt_to_sa.o fmt_tofrom_array.o fmt_urlencoded.o fmt_uuencoded.o fmt_xml.o fmt_yenc.o scan_base64.o scan_base64url.o scan_cescape.o scan_hexdump.o scan_html.o scan_jsonescape.o scan_ldapescape.o scan_quotedprintable.o scan_to_array.o scan_to_sa.o scan_tofrom_array.o scan_urlencoded.o scan_uuencoded.o scan_yenc.o 
 CDB_OBJS=cdb.o cdb_hash.o cdb_make.o cdb_traverse.o 
 CRITBIT_OBJS=critbit.o 
 
@@ -782,7 +782,7 @@ clean:
 	rm -f *.o *.a *.da *.bbg *.bb core t haveip6.h haven2i.h \
 havesl.h haveinline.h iopause.h select.h havekqueue.h haveepoll.h \
 libepoll havesigio.h havebsdsf.h havesendfile.h havescope.h havedevpoll.h \
-dep libsocket havealloca.h haveuint128.h entities.h ent
+dep libsocket havealloca.h haveuint128.h entities.h ent havepread.h
 
 INCLUDES=buffer.h byte.h fmt.h ip4.h ip6.h mmap.h scan.h socket.h str.h stralloc.h \
 uint16.h uint32.h uint64.h open.h textcode.h tai.h taia.h dns.h iopause.h case.h \
@@ -890,6 +890,11 @@ haveuint128.h: tryuint128.c
 	if $(DIET) $(CCC) $(CFLAGS) -c tryuint128.c >/dev/null 2>&1; then echo "#define HAVE_UINT128"; fi > $@
 	-rm -f tryuint128.o
 
+havepread.h: trypread.c
+	-rm -f $@
+	if $(DIET) $(CCC) $(CFLAGS) -c trypread.c >/dev/null 2>&1; then echo "#define HAVE_PREAD"; fi > $@
+	-rm -f trypread.o
+
 iopause.h: iopause.h1 iopause.h2 trypoll.c
 	-rm -f $@
 	if $(DIET) $(CCC) $(CFLAGS) -o t trypoll.c >/dev/null 2>&1; then cp iopause.h2 iopause.h; else cp iopause.h1 iopause.h; fi
diff --git a/cdb/cdb.c b/cdb/cdb.c
index 1c55de8..cbba320 100644
--- a/cdb/cdb.c
+++ b/cdb/cdb.c
@@ -6,6 +6,7 @@
 #include <errno.h>
 #include "byte.h"
 #include "cdb.h"
+#include "havepread.h"
 #ifdef __MINGW32__
 #include "windows.h"
 #else
@@ -63,16 +64,25 @@ int cdb_read(struct cdb *c,unsigned char *buf,unsigned long len,uint32 pos) {
     byte_copy(buf,len,c->map + pos);
   }
   else {
+#ifndef HAVE_PREAD
     if (lseek(c->fd,pos,SEEK_SET) == -1) return -1;
+#endif
     while (len > 0) {
-      int r;
+      ssize_t r;
       do
+#ifdef HAVE_PREAD
+	r = pread(c->fd,buf,len,pos);
+#else
         r = read(c->fd,buf,len);
+#endif
       while ((r == -1) && (errno == EINTR));
       if (r == -1) return -1;
       if (r == 0) goto FORMAT;
       buf += r;
       len -= r;
+#ifdef HAVE_PREAD
+      pos += r;
+#endif
     }
   }
   return 0;
diff --git a/io/io_mmapwritefile.c b/io/io_mmapwritefile.c
index dd649b2..964c29b 100644
--- a/io/io_mmapwritefile.c
+++ b/io/io_mmapwritefile.c
@@ -8,12 +8,13 @@
 #include <sys/mman.h>
 #endif
 #include <errno.h>
+#include "havepread.h"
 
 #define BUFSIZE 16384
 
 int64 io_mmapwritefile(int64 out,int64 in,uint64 off,uint64 bytes,io_write_callback writecb) {
   char buf[BUFSIZE];
-  int n,m;
+  ssize_t n,m;
   uint64 sent=0;
   io_entry* e=iarray_get(&io_fds,out);
   if (e) {
@@ -92,12 +93,20 @@ int64 io_mmapwritefile(int64 out,int64 in,uint64 off,uint64 bytes,io_write_callb
     return sent;
   }
 readwrite:
+#ifndef HAVE_PREAD
   if (lseek(in,off,SEEK_SET) != (off_t)off)
     return -1;
+#endif
   while (bytes>0) {
     char* tmp=buf;
+#ifdef HAVE_PREAD
+    if ((n=pread(in,tmp,(bytes<BUFSIZE)?bytes:BUFSIZE,off))<=0)
+      return (sent?(int64)sent:-1);
+    off+=n;
+#else
     if ((n=read(in,tmp,(bytes<BUFSIZE)?bytes:BUFSIZE))<=0)
       return (sent?(int64)sent:-1);
+#endif
     while (n>0) {
       if ((m=writecb(out,tmp,n))<0) {
 	if (m==-1) {