diff --git a/configure.ac b/configure.ac
index 09ff17f03..42e273f88 100644
--- a/configure.ac
+++ b/configure.ac
@@ -77,8 +77,6 @@ fi
 ])
 
 NEED_PROG(curl, curl)
-NEED_PROG(bzip2, bzip2)
-NEED_PROG(bunzip2, bunzip2)
 NEED_PROG(shell, sh)
 AC_PATH_PROG(xmllint, xmllint, false)
 AC_PATH_PROG(xsltproc, xsltproc, false)
@@ -145,6 +143,26 @@ AC_SUBST(aterm_lib)
 AC_SUBST(aterm_include)
 AC_SUBST(aterm_bin)
 
+AC_ARG_WITH(bzip2, AC_HELP_STRING([--with-bzip2=PATH],
+  [prefix of bzip2]),
+  bzip2=$withval, bzip2=)
+if test -z "$bzip2"; then
+   AC_CHECK_LIB(bz2, BZ2_bzWriteOpen,
+     [bzip2_lib="-lbz2"], [AC_MSG_ERROR([cannot find -lbz (bzip2)])])
+   AC_CHECK_HEADER(bzlib.h, 
+     [bzip2_include=""], [AC_MSG_ERROR([cannot find bzlib.h (bzip2)])])
+   AC_PATH_PROG(bzip2_prog, bzip2,
+     [AC_MSG_ERROR([cannot find bzip2])])
+   bzip2_bin=$(dirname $bzip2_prog)
+else
+   bzip2_lib="-L$bzip2/lib -lbz2"
+   bzip2_include="-I$bzip2/include"
+   bzip2_bin="$bzip2/bin"
+fi   
+AC_SUBST(bzip2_lib)
+AC_SUBST(bzip2_include)
+AC_SUBST(bzip2_bin)
+
 AC_CHECK_LIB(pthread, pthread_mutex_init)
 
 AC_ARG_ENABLE(init-state, AC_HELP_STRING([--disable-init-state],
@@ -203,7 +221,7 @@ AC_CONFIG_FILES([Makefile
    src/nix-instantiate/Makefile
    src/nix-env/Makefile
    src/nix-log2xml/Makefile
-   src/bsdiff-4.2/Makefile
+   src/bsdiff-4.3/Makefile
    scripts/Makefile
    corepkgs/Makefile
    corepkgs/nar/Makefile
diff --git a/src/Makefile.am b/src/Makefile.am
index 3167105ff..1cdbc558a 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,5 +1,5 @@
 SUBDIRS = bin2c boost libutil libstore libmain nix-store nix-hash \
- libexpr nix-instantiate nix-env nix-log2xml bsdiff-4.2
+ libexpr nix-instantiate nix-env nix-log2xml bsdiff-4.3
 
 EXTRA_DIST = aterm-helper.pl
 
diff --git a/src/bsdiff-4.2/LICENSE b/src/bsdiff-4.2/LICENSE
deleted file mode 100644
index c146b5b39..000000000
--- a/src/bsdiff-4.2/LICENSE
+++ /dev/null
@@ -1,121 +0,0 @@
-BSD Protection License
-February 2002
-
-Preamble
---------
-
-The Berkeley Software Distribution ("BSD") license has proven very effective
-over the years at allowing for a wide spread of work throughout both
-commercial and non-commercial products.  For programmers whose primary
-intention is to improve the general quality of available software, it is
-arguable that there is no better license than the BSD license, as it
-permits improvements to be used wherever they will help, without idealogical
-or metallic constraint.
-
-This is of particular value to those who produce reference implementations
-of proposed standards: The case of TCP/IP clearly illustrates that freely
-and universally available implementations leads the rapid acceptance of
-standards -- often even being used instead of a de jure standard (eg, OSI
-network models).
-
-With the rapid proliferation of software licensed under the GNU General
-Public License, however, the continued success of this role is called into
-question.  Given that the inclusion of a few lines of "GPL-tainted" work
-into a larger body of work will result in restricted distribution -- and
-given that further work will likely build upon the "tainted" portions,
-making them difficult to remove at a future date -- there are inevitable
-circumstances where authors would, in order to protect their goal of
-providing for the widespread usage of their work, wish to guard against
-such "GPL-taint".
-
-In addition, one can imagine that companies which operate by producing and
-selling (possibly closed-source) code would wish to protect themselves
-against the rise of a GPL-licensed competitor.  While under existing
-licenses this would mean not releasing their code under any form of open
-license, if a license existed under which they could incorporate any
-improvements back into their own (commercial) products then they might be
-far more willing to provide for non-closed distribution.
-
-For the above reasons, we put forth this "BSD Protection License": A
-license designed to retain the freedom granted by the BSD license to use
-licensed works in a wide variety of settings, both non-commercial and
-commercial, while protecting the work from having future contributors
-restrict that freedom.
-
-The precise terms and conditions for copying, distribution, and
-modification follow.
-
-BSD PROTECTION LICENSE
-TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION, AND MODIFICATION
-----------------------------------------------------------------
-
-0. Definitions.
-   a) "Program", below, refers to any program or work distributed under
-      the terms of this license.
-   b) A "work based on the Program", below, refers to either the Program
-      or any derivative work under copyright law.
-   c) "Modification", below, refers to the act of creating derivative works.
-   d) "You", below, refers to each licensee.
-
-1. Scope.
-   This license governs the copying, distribution, and modification of the
-   Program.  Other activities are outside the scope of this license; The
-   act of running the Program is not restricted, and the output from the
-   Program is covered only if its contents constitute a work based on the
-   Program.
-
-2. Verbatim copies.
-   You may copy and distribute verbatim copies of the Program as you
-   receive it, in any medium, provided that you conspicuously and
-   appropriately publish on each copy an appropriate copyright notice; keep
-   intact all the notices that refer to this License and to the absence of
-   any warranty; and give any other recipients of the Program a copy of this
-   License along with the Program.
-
-3. Modification and redistribution under closed license.
-   You may modify your copy or copies of the Program, and distribute
-   the resulting derivative works, provided that you meet the
-   following conditions:
-   a) The copyright notice and disclaimer on the Program must be reproduced
-      and included in the source code, documentation, and/or other materials
-      provided in a manner in which such notices are normally distributed.
-   b) The derivative work must be clearly identified as such, in order that
-      it may not be confused with the original work.
-   c) The license under which the derivative work is distributed must
-      expressly prohibit the distribution of further derivative works.
-
-4. Modification and redistribution under open license.
-   You may modify your copy or copies of the Program, and distribute
-   the resulting derivative works, provided that you meet the
-   following conditions:
-   a) The copyright notice and disclaimer on the Program must be reproduced
-      and included in the source code, documentation, and/or other materials
-      provided in a manner in which such notices are normally distributed.
-   b) You must clearly indicate the nature and date of any changes made
-      to the Program.  The full details need not necessarily be included in
-      the individual modified files, provided that each modified file is
-      clearly marked as such and instructions are included on where the
-      full details of the modifications may be found.
-   c) You must cause any work that you distribute or publish, that in whole
-      or in part contains or is derived from the Program or any part
-      thereof, to be licensed as a whole at no charge to all third
-      parties under the terms of this License.
-
-5. Implied acceptance.
-   You may not copy or distribute the Program or any derivative works except
-   as expressly provided under this license.  Consequently, any such action
-   will be taken as implied acceptance of the terms of this license.
-
-6. NO WARRANTY.
-   THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
-   INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
-   AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
-   THE COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
-   REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE FOR ANY DIRECT,
-   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
-   ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING, BUT
-   NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
-   USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
-   ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
-   TORT, EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
-   POSSIBILITY OF SUCH DAMAGES.
diff --git a/src/bsdiff-4.2/Makefile.am b/src/bsdiff-4.2/Makefile.am
deleted file mode 100644
index 70f2ead7c..000000000
--- a/src/bsdiff-4.2/Makefile.am
+++ /dev/null
@@ -1,7 +0,0 @@
-libexec_PROGRAMS = bsdiff bspatch
-
-bsdiff_SOURCES = bsdiff.c
-
-bspatch_SOURCES = bspatch.c
-
-AM_CFLAGS = -O3 -DBZIP2=\"$(bzip2)\"
diff --git a/src/bsdiff-4.2/Makefile.old b/src/bsdiff-4.2/Makefile.old
deleted file mode 100644
index ce5dd344d..000000000
--- a/src/bsdiff-4.2/Makefile.old
+++ /dev/null
@@ -1,18 +0,0 @@
-CFLAGS		+=	-O3
-.ifdef BZIP2
-CFLAGS		+=	-DBZIP2=\"${BZIP2}\"
-.endif
-
-PREFIX		?=	/usr/local
-INSTALL_PROGRAM	?=	${INSTALL} -c -s -m 555
-INSTALL_MAN	?=	${INSTALL} -c -m 444
-
-all:		bsdiff bspatch
-bsdiff:		bsdiff.c
-bspatch:	bspatch.c
-
-install:
-	${INSTALL_PROGRAM} bsdiff bspatch ${PREFIX}/bin
-.ifndef WITHOUT_MAN
-	${INSTALL_MAN} bsdiff.1 bspatch.1 ${PREFIX}/man/man1
-.endif
diff --git a/src/bsdiff-4.2/bsdiff.1 b/src/bsdiff-4.2/bsdiff.1
deleted file mode 100644
index 8d3926d32..000000000
--- a/src/bsdiff-4.2/bsdiff.1
+++ /dev/null
@@ -1,36 +0,0 @@
-.Dd May 18, 2003
-.Dt BSDIFF 1
-.Os FreeBSD
-.Sh NAME
-.Nm bsdiff
-.Nd generate a patch between two binary files
-.Sh SYNOPSIS
-.Nm
-.Ao Ar oldfile Ac Ao Ar newfile Ac Ao Ar patchfile Ac
-.Sh DESCRIPTION
-.Nm
-compares
-.Ao Ar oldfile Ac
-to
-.Ao Ar newfile Ac
-and writes to
-.Ao Ar patchfile Ac
-a binary patch suitable for use by bspatch(1).
-When
-.Ao Ar oldfile Ac
-and
-.Ao Ar newfile Ac
-are two versions of an executable program, the
-patches produced are on average a factor of five smaller
-than those produced by any other binary patch tool known
-to the author.
-.Pp
-.Nm
-uses memory equal to 17 times the size of 
-.Ao Ar oldfile Ac ,
-and requires
-an absolute minimum working set size of 8 times the size of oldfile.
-.Sh SEE ALSO
-.Xr bspatch 1
-.Sh AUTHORS
-.An Colin Percival Aq cperciva@daemonology.net
diff --git a/src/bsdiff-4.2/bspatch.1 b/src/bsdiff-4.2/bspatch.1
deleted file mode 100644
index b243f2b7b..000000000
--- a/src/bsdiff-4.2/bspatch.1
+++ /dev/null
@@ -1,32 +0,0 @@
-.Dd May 18, 2003
-.Dt BSPATCH 1
-.Os FreeBSD
-.Sh NAME
-.Nm bspatch
-.Nd apply a patch built with bsdiff(1)
-.Sh SYNOPSIS
-.Nm
-.Ao Ar oldfile Ac Ao Ar newfile Ac Ao Ar patchfile Ac
-.Sh DESCRIPTION
-.Nm
-generates
-.Ao Ar newfile Ac
-from
-.Ao Ar oldfile Ac
-and
-.Ao Ar patchfile Ac
-where
-.Ao Ar patchfile Ac
-is a binary patch built by bsdiff(1).
-.Pp
-.Nm
-uses memory equal to the size of 
-.Ao Ar oldfile Ac
-plus the size of 
-.Ao Ar newfile Ac ,
-but can tolerate a very small working set without a dramatic loss
-of performance.
-.Sh SEE ALSO
-.Xr bsdiff 1
-.Sh AUTHORS
-.An Colin Percival Aq cperciva@daemonology.net
diff --git a/src/bsdiff-4.2/bspatch.c b/src/bsdiff-4.2/bspatch.c
deleted file mode 100644
index 1386a7096..000000000
--- a/src/bsdiff-4.2/bspatch.c
+++ /dev/null
@@ -1,216 +0,0 @@
-/*
-  .c -- Binary patcher
-
-  Copyright 2003,2004 Colin Percival
-
-  For the terms under which this work may be distributed, please see
-  the adjoining file "LICENSE".
-*/
-
-#ifndef BZIP2
-#define BZIP2 "/usr/bin/bzip2"
-#endif
-
-#include <stdlib.h>
-#include <stdio.h>
-#include <err.h>
-#include <unistd.h>
-#include <fcntl.h>
-#include <sys/wait.h>
-
-ssize_t loopread(int d,void *buf,size_t nbytes)
-{
-	ssize_t ptr,lenread;
-
-	for(ptr=0;ptr<nbytes;ptr+=lenread) {
-		lenread=read(d,buf+ptr,nbytes-ptr);
-		if(lenread==0) return ptr;
-		if(lenread==-1) return -1;
-	};
-	return ptr;
-}
-
-int bz2read(int fd,off_t offset,off_t len,char * fname,pid_t * pids)
-{
-	int p0[2],p1[2];
-	u_char * data;
-
-	if((pipe(p0)==-1) || (pipe(p1)==-1)) err(1,NULL);
-
-	if((pids[0]=fork())==-1) err(1,NULL);
-	if(pids[0]==0) {
-		if(close(0) || close(1) || close(p0[0]) ||
-			close(p1[0]) || close(p1[1])) err(1,NULL);
-		if((data=malloc(len+1))==NULL) err(1,NULL);
-		if((pread(fd,data,len,offset)!=len) || close(fd))
-			err(1,"%s",fname);
-		if((write(p0[1],data,len)!=len) || close(p0[1]))
-			err(1,NULL);
-		free(data);
-		_exit(0);
-	};
-
-	if((pids[1]=fork())==-1) err(1,NULL);
-	if(pids[1]==0) {
-		if(close(0) || close(1) || close(p0[1]) ||
-			close(p1[0])) err(1,NULL);
-		if((dup2(p0[0],0)==-1) || close(p0[0])) err(1,NULL);
-		if((dup2(p1[1],1)==-1) || close(p1[1])) err(1,NULL);
-		if(close(fd)==-1) err(1,"%s",fname);
-
-		execl(BZIP2,BZIP2,"-dc",NULL);
-		err(1,"%s",BZIP2);
-	};
-
-	if(close(p0[0]) || close(p0[1]) || close(p1[1])) err(1,NULL);
-
-	return p1[0];
-}
-
-off_t offtin(u_char *buf)
-{
-	off_t y;
-
-	y=buf[7]&0x7F;
-	y=y*256;y+=buf[6];
-	y=y*256;y+=buf[5];
-	y=y*256;y+=buf[4];
-	y=y*256;y+=buf[3];
-	y=y*256;y+=buf[2];
-	y=y*256;y+=buf[1];
-	y=y*256;y+=buf[0];
-
-	if(buf[7]&0x80) y=-y;
-
-	return y;
-}
-
-int main(int argc,char * argv[])
-{
-	int fd,ctrlpipe,diffpipe,extrapipe;
-	pid_t pids[6];
-	ssize_t patchsize,oldsize,newsize;
-	ssize_t bzctrllen,bzdatalen;
-	u_char header[32],buf[8];
-	int version=0;
-	u_char *old, *new;
-	off_t oldpos,newpos;
-	off_t ctrl[3];
-	off_t lenread;
-	off_t i;
-
-	if(argc!=4) errx(1,"usage: %s oldfile newfile patchfile\n",argv[0]);
-
-	if(((fd=open(argv[3],O_RDONLY,0))<0) ||
-		((patchsize=lseek(fd,0,SEEK_END))==-1) ||
-		(lseek(fd,0,SEEK_SET)!=0)) err(1,"%s",argv[3]);
-	if(patchsize<32) errx(1,"Corrupt patch\n");
-
-	/*
-	  Ok, this is going to be messy.  There are two different patch
-	formats which we need to support.
-
-	  The old format (pre-4.0) is:
-		0	8	"QSUFDIFF" or "BSDIFF30"
-		8	8	X
-		16	8	Y
-		24	8	sizeof(newfile)
-		32	X	bzip2(control block)
-		32+X	Y	bzip2(data block)
-	with control block a set of pairs (x,y) meaning "seek forward
-	in oldfile by y bytes, and add the next x bytes to x bytes from
-	the data block".
-
-	  The new format (4.0) is:
-		0	8	"BSDIFF40"
-		8	8	X
-		16	8	Y
-		24	8	sizeof(newfile)
-		32	X	bzip2(control block)
-		32+X	Y	bzip2(diff block)
-		32+X+Y	???	bzip2(extra block)
-	with control block a set of triples (x,y,z) meaning "add x bytes
-	from oldfile to x bytes from the diff block; copy y bytes from the
-	extra block; seek forwards in oldfile by z bytes".
-	*/
-
-	if(read(fd,header,32)!=32) err(1,"%s",argv[3]);
-	if(memcmp(header,"QSUFDIFF",8)==0) version=1;
-	if(memcmp(header,"BSDIFF30",8)==0) version=1;
-	if(memcmp(header,"BSDIFF40",8)==0) version=2;
-
-	if(!version) errx(1,"Corrupt patch\n");
-
-	bzctrllen=offtin(header+8);
-	bzdatalen=offtin(header+16);
-	newsize=offtin(header+24);
-	if((bzctrllen<0) || (bzdatalen<0) || (newsize<0) ||
-		((version==1) && (32+bzctrllen+bzdatalen!=patchsize)))
-		errx(1,"Corrupt patch\n");
-
-	ctrlpipe=bz2read(fd,32,bzctrllen,argv[3],pids);
-	diffpipe=bz2read(fd,32+bzctrllen,bzdatalen,argv[3],pids+2);
-	if(version==2) {
-		extrapipe=bz2read(fd,32+bzctrllen+bzdatalen,
-			patchsize-(32+bzctrllen+bzdatalen),argv[3],pids+4);
-	};
-
-	if(close(fd)==-1) err(1,"%s",argv[3]);
-	if(((fd=open(argv[1],O_RDONLY,0))<0) ||
-		((oldsize=lseek(fd,0,SEEK_END))==-1) ||
-		((old=malloc(oldsize+1))==NULL) ||
-		(lseek(fd,0,SEEK_SET)!=0) ||
-		(read(fd,old,oldsize)!=oldsize) ||
-		(close(fd)==-1)) err(1,"%s",argv[1]);
-	if((new=malloc(newsize+1))==NULL) err(1,NULL);
-
-	oldpos=0;newpos=0;
-	while(newpos<newsize) {
-		for(i=0;i<=version;i++) {
-			if((lenread=loopread(ctrlpipe,buf,8))<0) err(1,NULL);
-			if(lenread<8) errx(1,"Corrupt patch\n");
-			ctrl[i]=offtin(buf);
-		};
-
-		if(version==1) oldpos+=ctrl[1];
-
-		if(newpos+ctrl[0]>newsize) errx(1,"Corrupt patch\n");
-		if((lenread=loopread(diffpipe,new+newpos,ctrl[0]))<0)
-			err(1,NULL);
-		if(lenread!=ctrl[0]) errx(1,"Corrupt patch\n");
-		for(i=0;i<ctrl[0];i++)
-			if((oldpos+i>=0) && (oldpos+i<oldsize))
-				new[newpos+i]+=old[oldpos+i];
-		newpos+=ctrl[0];
-		oldpos+=ctrl[0];
-
-		if(version==2) {
-			if(newpos+ctrl[1]>newsize) errx(1,"Corrupt patch\n");
-			if((lenread=loopread(extrapipe,new+newpos,ctrl[1]))<0)
-				err(1,NULL);
-			if(lenread!=ctrl[1]) errx(1,"Corrupt patch\n");
-
-			newpos+=ctrl[1];
-			oldpos+=ctrl[2];
-		};
-	};
-
-	if(loopread(ctrlpipe,buf,1)!=0) errx(1,"Corrupt patch\n");
-	if(loopread(diffpipe,buf,1)!=0) errx(1,"Corrupt patch\n");
-	if(version==2)
-		if(loopread(extrapipe,buf,1)!=0) errx(1,"Corrupt patch\n");
-
-	if(close(ctrlpipe) || close(diffpipe) || 
-		((version==2) && close(extrapipe)))
-		err(1,NULL);
-	for(i=0;i<(version+1)*2;i++) waitpid(pids[i],NULL,0);
-
-	if(((fd=open(argv[2],O_CREAT|O_TRUNC|O_WRONLY,0666))<0) ||
-		(write(fd,new,newsize)!=newsize) || (close(fd)==-1))
-		err(1,"%s",argv[2]);
-
-	free(new);
-	free(old);
-
-	return 0;
-}
diff --git a/src/bsdiff-4.3/Makefile.am b/src/bsdiff-4.3/Makefile.am
new file mode 100644
index 000000000..4b3af0783
--- /dev/null
+++ b/src/bsdiff-4.3/Makefile.am
@@ -0,0 +1,11 @@
+libexec_PROGRAMS = bsdiff bspatch
+
+bsdiff_SOURCES = bsdiff.c
+
+bsdiff_LDADD = ${bzip2_lib}
+
+bspatch_SOURCES = bspatch.c
+
+bspatch_LDADD = ${bzip2_lib}
+
+AM_CFLAGS = -O3 ${bzip2_include}
diff --git a/src/bsdiff-4.3/bsdiff.1 b/src/bsdiff-4.3/bsdiff.1
new file mode 100644
index 000000000..ead6c4deb
--- /dev/null
+++ b/src/bsdiff-4.3/bsdiff.1
@@ -0,0 +1,63 @@
+.\"-
+.\" Copyright 2003-2005 Colin Percival
+.\" All rights reserved
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted providing that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+.\" IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+.\" POSSIBILITY OF SUCH DAMAGE.
+.\"
+.\" $FreeBSD: src/usr.bin/bsdiff/bsdiff/bsdiff.1,v 1.1 2005/08/06 01:59:05 cperciva Exp $
+.\"
+.Dd May 18, 2003
+.Dt BSDIFF 1
+.Os FreeBSD
+.Sh NAME
+.Nm bsdiff
+.Nd generate a patch between two binary files
+.Sh SYNOPSIS
+.Nm
+.Ao Ar oldfile Ac Ao Ar newfile Ac Ao Ar patchfile Ac
+.Sh DESCRIPTION
+.Nm
+compares
+.Ao Ar oldfile Ac
+to
+.Ao Ar newfile Ac
+and writes to
+.Ao Ar patchfile Ac
+a binary patch suitable for use by bspatch(1).
+When
+.Ao Ar oldfile Ac
+and
+.Ao Ar newfile Ac
+are two versions of an executable program, the
+patches produced are on average a factor of five smaller
+than those produced by any other binary patch tool known
+to the author.
+.Pp
+.Nm
+uses memory equal to 17 times the size of 
+.Ao Ar oldfile Ac ,
+and requires
+an absolute minimum working set size of 8 times the size of oldfile.
+.Sh SEE ALSO
+.Xr bspatch 1
+.Sh AUTHORS
+.An Colin Percival Aq cperciva@freebsd.org
diff --git a/src/bsdiff-4.2/bsdiff.c b/src/bsdiff-4.3/bsdiff.c
similarity index 60%
rename from src/bsdiff-4.2/bsdiff.c
rename to src/bsdiff-4.3/bsdiff.c
index f47226c1e..150a7f79c 100644
--- a/src/bsdiff-4.2/bsdiff.c
+++ b/src/bsdiff-4.3/bsdiff.c
@@ -1,27 +1,46 @@
-/*
-  bsdiff.c -- Binary patch generator.
+/*-
+ * Copyright 2003-2005 Colin Percival
+ * All rights reserved
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted providing that the following conditions 
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
 
-  Copyright 2003 Colin Percival
-
-  For the terms under which this work may be distributed, please see
-  the adjoining file "LICENSE".
-*/
-
-#ifndef BZIP2
-#define BZIP2 "/usr/bin/bzip2"
+#if 0
+__FBSDID("$FreeBSD: src/usr.bin/bsdiff/bsdiff/bsdiff.c,v 1.1 2005/08/06 01:59:05 cperciva Exp $");
 #endif
 
-#include <stdlib.h>
-#include <stdio.h>
-#include <string.h>
+#include <sys/types.h>
+
+#include <bzlib.h>
 #include <err.h>
-#include <unistd.h>
 #include <fcntl.h>
-#include <sys/wait.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
 
 #define MIN(x,y) (((x)<(y)) ? (x) : (y))
 
-void split(off_t *I,off_t *V,off_t start,off_t len,off_t h)
+static void split(off_t *I,off_t *V,off_t start,off_t len,off_t h)
 {
 	off_t i,j,k,x,tmp,jj,kk;
 
@@ -82,7 +101,7 @@ void split(off_t *I,off_t *V,off_t start,off_t len,off_t h)
 	if(start+len>kk) split(I,V,kk,start+len-kk,h);
 }
 
-void qsufsort(off_t *I,off_t *V,u_char *old,off_t oldsize)
+static void qsufsort(off_t *I,off_t *V,u_char *old,off_t oldsize)
 {
 	off_t buckets[256];
 	off_t i,h,len;
@@ -120,7 +139,7 @@ void qsufsort(off_t *I,off_t *V,u_char *old,off_t oldsize)
 	for(i=0;i<oldsize+1;i++) I[V[i]]=i;
 }
 
-off_t matchlen(u_char *old,off_t oldsize,u_char *new,off_t newsize)
+static off_t matchlen(u_char *old,off_t oldsize,u_char *new,off_t newsize)
 {
 	off_t i;
 
@@ -130,7 +149,7 @@ off_t matchlen(u_char *old,off_t oldsize,u_char *new,off_t newsize)
 	return i;
 }
 
-off_t search(off_t *I,u_char *old,off_t oldsize,
+static off_t search(off_t *I,u_char *old,off_t oldsize,
 		u_char *new,off_t newsize,off_t st,off_t en,off_t *pos)
 {
 	off_t x,y;
@@ -156,7 +175,7 @@ off_t search(off_t *I,u_char *old,off_t oldsize,
 	};
 }
 
-void offtout(off_t x,u_char *buf)
+static void offtout(off_t x,u_char *buf)
 {
 	off_t y;
 
@@ -176,25 +195,23 @@ void offtout(off_t x,u_char *buf)
 
 int main(int argc,char *argv[])
 {
-	int fd,p[2];
-	pid_t pid;
+	int fd;
 	u_char *old,*new;
 	off_t oldsize,newsize;
 	off_t *I,*V;
-
 	off_t scan,pos,len;
 	off_t lastscan,lastpos,lastoffset;
 	off_t oldscore,scsc;
-
 	off_t s,Sf,lenf,Sb,lenb;
 	off_t overlap,Ss,lens;
 	off_t i;
-
 	off_t dblen,eblen;
 	u_char *db,*eb;
-
 	u_char buf[8];
 	u_char header[32];
+	FILE * pf;
+	BZFILE * pfbz2;
+	int bz2err;
 
 	if(argc!=4) errx(1,"usage: %s oldfile newfile patchfile\n",argv[0]);
 
@@ -228,8 +245,9 @@ int main(int argc,char *argv[])
 	dblen=0;
 	eblen=0;
 
-	if((fd=open(argv[3],O_CREAT|O_TRUNC|O_WRONLY,0666))<0)
-		err(1,"%s",argv[3]);
+	/* Create the patch file */
+	if ((pf = fopen(argv[3], "w")) == NULL)
+		err(1, "%s", argv[3]);
 
 	/* Header is
 		0	8	 "BSDIFF40"
@@ -242,20 +260,15 @@ int main(int argc,char *argv[])
 		??	??	Bzip2ed diff block
 		??	??	Bzip2ed extra block */
 	memcpy(header,"BSDIFF40",8);
-	memset(header+8,0,24);
-	if(write(fd,header,32)!=32) err(1,"%s",argv[3]);
-
-	if((pipe(p)==-1) || ((pid=fork())==-1)) err(1,NULL);
-	if(pid==0) {
-		if((close(0)==-1) || (close(1)==-1) || (dup2(fd,1)==-1) ||
-			(dup2(p[0],0)==-1) || (close(fd)==-1) ||
-			(close(p[0])==-1) || (close(p[1])==-1))
-			err(1,NULL);
-		execl(BZIP2,BZIP2,"-zc",NULL);
-		err(1,"%s",BZIP2);
-	};
-	if(close(p[0])==-1) err(1,NULL);
+	offtout(0, header + 8);
+	offtout(0, header + 16);
+	offtout(newsize, header + 24);
+	if (fwrite(header, 32, 1, pf) != 1)
+		err(1, "fwrite(%s)", argv[3]);
 
+	/* Compute the differences, writing ctrl as we go */
+	if ((pfbz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)) == NULL)
+		errx(1, "BZ2_bzWriteOpen, bz2err = %d", bz2err);
 	scan=0;len=0;
 	lastscan=0;lastpos=0;lastoffset=0;
 	while(scan<newsize) {
@@ -319,62 +332,68 @@ int main(int argc,char *argv[])
 			eblen+=(scan-lenb)-(lastscan+lenf);
 
 			offtout(lenf,buf);
-			if(write(p[1],buf,8)!=8) err(1,NULL);
+			BZ2_bzWrite(&bz2err, pfbz2, buf, 8);
+			if (bz2err != BZ_OK)
+				errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
+
 			offtout((scan-lenb)-(lastscan+lenf),buf);
-			if(write(p[1],buf,8)!=8) err(1,NULL);
+			BZ2_bzWrite(&bz2err, pfbz2, buf, 8);
+			if (bz2err != BZ_OK)
+				errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
+
 			offtout((pos-lenb)-(lastpos+lenf),buf);
-			if(write(p[1],buf,8)!=8) err(1,NULL);
+			BZ2_bzWrite(&bz2err, pfbz2, buf, 8);
+			if (bz2err != BZ_OK)
+				errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
 
 			lastscan=scan-lenb;
 			lastpos=pos-lenb;
 			lastoffset=pos-scan;
 		};
 	};
+	BZ2_bzWriteClose(&bz2err, pfbz2, 0, NULL, NULL);
+	if (bz2err != BZ_OK)
+		errx(1, "BZ2_bzWriteClose, bz2err = %d", bz2err);
 
-	if((close(p[1])==-1) || (waitpid(pid,NULL,0)!=pid)) err(1,NULL);
+	/* Compute size of compressed ctrl data */
+	if ((len = ftello(pf)) == -1)
+		err(1, "ftello");
+	offtout(len-32, header + 8);
 
-	if((len=lseek(fd,0,SEEK_END))==-1) err(1,"%s",argv[3]);
-	offtout(len-32,buf);
-	if((lseek(fd,8,SEEK_SET)!=8) || (write(fd,buf,8)!=8))
-		err(1,"%s",argv[3]);
-	offtout(newsize,buf);
-	if((lseek(fd,24,SEEK_SET)!=24) || (write(fd,buf,8)!=8))
-		err(1,"%s",argv[3]);
+	/* Write compressed diff data */
+	if ((pfbz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)) == NULL)
+		errx(1, "BZ2_bzWriteOpen, bz2err = %d", bz2err);
+	BZ2_bzWrite(&bz2err, pfbz2, db, dblen);
+	if (bz2err != BZ_OK)
+		errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
+	BZ2_bzWriteClose(&bz2err, pfbz2, 0, NULL, NULL);
+	if (bz2err != BZ_OK)
+		errx(1, "BZ2_bzWriteClose, bz2err = %d", bz2err);
 
-	if(lseek(fd,0,SEEK_END)==-1) err(1,"%s",argv[3]);
-	if((pipe(p)==-1) || ((pid=fork())==-1)) err(1,NULL);
-	if(pid==0) {
-		if((close(0)==-1) || (close(1)==-1) || (dup2(fd,1)==-1) ||
-			(dup2(p[0],0)==-1) || (close(fd)==-1) ||
-			(close(p[0])==-1) || (close(p[1])==-1))
-			err(1,NULL);
-		execl(BZIP2,BZIP2,"-zc",NULL);
-		err(1,"%s",BZIP2);
-	};
-	if(close(p[0])==-1) err(1,NULL);
-	if(write(p[1],db,dblen)!=dblen) err(1,NULL);
-	if((close(p[1])==-1) || (waitpid(pid,NULL,0)!=pid)) err(1,NULL);
+	/* Compute size of compressed diff data */
+	if ((newsize = ftello(pf)) == -1)
+		err(1, "ftello");
+	offtout(newsize - len, header + 16);
 
-	if((newsize=lseek(fd,0,SEEK_END))==-1) err(1,"%s",argv[3]);
-	offtout(newsize-len,buf);
-	if((lseek(fd,16,SEEK_SET)!=16) || (write(fd,buf,8)!=8))
-		err(1,"%s",argv[3]);
+	/* Write compressed extra data */
+	if ((pfbz2 = BZ2_bzWriteOpen(&bz2err, pf, 9, 0, 0)) == NULL)
+		errx(1, "BZ2_bzWriteOpen, bz2err = %d", bz2err);
+	BZ2_bzWrite(&bz2err, pfbz2, eb, eblen);
+	if (bz2err != BZ_OK)
+		errx(1, "BZ2_bzWrite, bz2err = %d", bz2err);
+	BZ2_bzWriteClose(&bz2err, pfbz2, 0, NULL, NULL);
+	if (bz2err != BZ_OK)
+		errx(1, "BZ2_bzWriteClose, bz2err = %d", bz2err);
 
-	if(lseek(fd,0,SEEK_END)==-1) err(1,"%s",argv[3]);
-	if((pipe(p)==-1) || ((pid=fork())==-1)) err(1,NULL);
-	if(pid==0) {
-		if((close(0)==-1) || (close(1)==-1) || (dup2(fd,1)==-1) ||
-			(dup2(p[0],0)==-1) || (close(fd)==-1) ||
-			(close(p[0])==-1) || (close(p[1])==-1))
-			err(1,NULL);
-		execl(BZIP2,BZIP2,"-zc",NULL);
-		err(1,"%s",BZIP2);
-	};
-	if(close(p[0])==-1) err(1,NULL);
-	if(write(p[1],eb,eblen)!=eblen) err(1,NULL);
-	if((close(p[1])==-1) || (waitpid(pid,NULL,0)!=pid)) err(1,NULL);
-	if(close(fd)==-1) err(1,"%s",argv[3]);
+	/* Seek to the beginning, write the header, and close the file */
+	if (fseeko(pf, 0, SEEK_SET))
+		err(1, "fseeko");
+	if (fwrite(header, 32, 1, pf) != 1)
+		err(1, "fwrite(%s)", argv[3]);
+	if (fclose(pf))
+		err(1, "fclose");
 
+	/* Free the memory we used */
 	free(db);
 	free(eb);
 	free(I);
diff --git a/src/bsdiff-4.3/bspatch.1 b/src/bsdiff-4.3/bspatch.1
new file mode 100644
index 000000000..82a2781aa
--- /dev/null
+++ b/src/bsdiff-4.3/bspatch.1
@@ -0,0 +1,59 @@
+.\"-
+.\" Copyright 2003-2005 Colin Percival
+.\" All rights reserved
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted providing that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+.\" IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+.\" POSSIBILITY OF SUCH DAMAGE.
+.\"
+.\" $FreeBSD: src/usr.bin/bsdiff/bspatch/bspatch.1,v 1.1 2005/08/06 01:59:06 cperciva Exp $
+.\"
+.Dd May 18, 2003
+.Dt BSPATCH 1
+.Os FreeBSD
+.Sh NAME
+.Nm bspatch
+.Nd apply a patch built with bsdiff(1)
+.Sh SYNOPSIS
+.Nm
+.Ao Ar oldfile Ac Ao Ar newfile Ac Ao Ar patchfile Ac
+.Sh DESCRIPTION
+.Nm
+generates
+.Ao Ar newfile Ac
+from
+.Ao Ar oldfile Ac
+and
+.Ao Ar patchfile Ac
+where
+.Ao Ar patchfile Ac
+is a binary patch built by bsdiff(1).
+.Pp
+.Nm
+uses memory equal to the size of 
+.Ao Ar oldfile Ac
+plus the size of 
+.Ao Ar newfile Ac ,
+but can tolerate a very small working set without a dramatic loss
+of performance.
+.Sh SEE ALSO
+.Xr bsdiff 1
+.Sh AUTHORS
+.An Colin Percival Aq cperciva@freebsd.org
diff --git a/src/bsdiff-4.3/bspatch.c b/src/bsdiff-4.3/bspatch.c
new file mode 100644
index 000000000..f4b821cba
--- /dev/null
+++ b/src/bsdiff-4.3/bspatch.c
@@ -0,0 +1,204 @@
+/*-
+ * Copyright 2003-2005 Colin Percival
+ * All rights reserved
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted providing that the following conditions 
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#if 0
+__FBSDID("$FreeBSD: src/usr.bin/bsdiff/bspatch/bspatch.c,v 1.1 2005/08/06 01:59:06 cperciva Exp $");
+#endif
+
+#include <bzlib.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <err.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+static off_t offtin(u_char *buf)
+{
+	off_t y;
+
+	y=buf[7]&0x7F;
+	y=y*256;y+=buf[6];
+	y=y*256;y+=buf[5];
+	y=y*256;y+=buf[4];
+	y=y*256;y+=buf[3];
+	y=y*256;y+=buf[2];
+	y=y*256;y+=buf[1];
+	y=y*256;y+=buf[0];
+
+	if(buf[7]&0x80) y=-y;
+
+	return y;
+}
+
+int main(int argc,char * argv[])
+{
+	FILE * f, * cpf, * dpf, * epf;
+	BZFILE * cpfbz2, * dpfbz2, * epfbz2;
+	int cbz2err, dbz2err, ebz2err;
+	int fd;
+	ssize_t oldsize,newsize;
+	ssize_t bzctrllen,bzdatalen;
+	u_char header[32],buf[8];
+	u_char *old, *new;
+	off_t oldpos,newpos;
+	off_t ctrl[3];
+	off_t lenread;
+	off_t i;
+
+	if(argc!=4) errx(1,"usage: %s oldfile newfile patchfile\n",argv[0]);
+
+	/* Open patch file */
+	if ((f = fopen(argv[3], "r")) == NULL)
+		err(1, "fopen(%s)", argv[3]);
+
+	/*
+	File format:
+		0	8	"BSDIFF40"
+		8	8	X
+		16	8	Y
+		24	8	sizeof(newfile)
+		32	X	bzip2(control block)
+		32+X	Y	bzip2(diff block)
+		32+X+Y	???	bzip2(extra block)
+	with control block a set of triples (x,y,z) meaning "add x bytes
+	from oldfile to x bytes from the diff block; copy y bytes from the
+	extra block; seek forwards in oldfile by z bytes".
+	*/
+
+	/* Read header */
+	if (fread(header, 1, 32, f) < 32) {
+		if (feof(f))
+			errx(1, "Corrupt patch\n");
+		err(1, "fread(%s)", argv[3]);
+	}
+
+	/* Check for appropriate magic */
+	if (memcmp(header, "BSDIFF40", 8) != 0)
+		errx(1, "Corrupt patch\n");
+
+	/* Read lengths from header */
+	bzctrllen=offtin(header+8);
+	bzdatalen=offtin(header+16);
+	newsize=offtin(header+24);
+	if((bzctrllen<0) || (bzdatalen<0) || (newsize<0))
+		errx(1,"Corrupt patch\n");
+
+	/* Close patch file and re-open it via libbzip2 at the right places */
+	if (fclose(f))
+		err(1, "fclose(%s)", argv[3]);
+	if ((cpf = fopen(argv[3], "r")) == NULL)
+		err(1, "fopen(%s)", argv[3]);
+	if (fseeko(cpf, 32, SEEK_SET))
+		err(1, "fseeko(%s, %lld)", argv[3],
+		    (long long)32);
+	if ((cpfbz2 = BZ2_bzReadOpen(&cbz2err, cpf, 0, 0, NULL, 0)) == NULL)
+		errx(1, "BZ2_bzReadOpen, bz2err = %d", cbz2err);
+	if ((dpf = fopen(argv[3], "r")) == NULL)
+		err(1, "fopen(%s)", argv[3]);
+	if (fseeko(dpf, 32 + bzctrllen, SEEK_SET))
+		err(1, "fseeko(%s, %lld)", argv[3],
+		    (long long)(32 + bzctrllen));
+	if ((dpfbz2 = BZ2_bzReadOpen(&dbz2err, dpf, 0, 0, NULL, 0)) == NULL)
+		errx(1, "BZ2_bzReadOpen, bz2err = %d", dbz2err);
+	if ((epf = fopen(argv[3], "r")) == NULL)
+		err(1, "fopen(%s)", argv[3]);
+	if (fseeko(epf, 32 + bzctrllen + bzdatalen, SEEK_SET))
+		err(1, "fseeko(%s, %lld)", argv[3],
+		    (long long)(32 + bzctrllen + bzdatalen));
+	if ((epfbz2 = BZ2_bzReadOpen(&ebz2err, epf, 0, 0, NULL, 0)) == NULL)
+		errx(1, "BZ2_bzReadOpen, bz2err = %d", ebz2err);
+
+	if(((fd=open(argv[1],O_RDONLY,0))<0) ||
+		((oldsize=lseek(fd,0,SEEK_END))==-1) ||
+		((old=malloc(oldsize+1))==NULL) ||
+		(lseek(fd,0,SEEK_SET)!=0) ||
+		(read(fd,old,oldsize)!=oldsize) ||
+		(close(fd)==-1)) err(1,"%s",argv[1]);
+	if((new=malloc(newsize+1))==NULL) err(1,NULL);
+
+	oldpos=0;newpos=0;
+	while(newpos<newsize) {
+		/* Read control data */
+		for(i=0;i<=2;i++) {
+			lenread = BZ2_bzRead(&cbz2err, cpfbz2, buf, 8);
+			if ((lenread < 8) || ((cbz2err != BZ_OK) &&
+			    (cbz2err != BZ_STREAM_END)))
+				errx(1, "Corrupt patch\n");
+			ctrl[i]=offtin(buf);
+		};
+
+		/* Sanity-check */
+		if(newpos+ctrl[0]>newsize)
+			errx(1,"Corrupt patch\n");
+
+		/* Read diff string */
+		lenread = BZ2_bzRead(&dbz2err, dpfbz2, new + newpos, ctrl[0]);
+		if ((lenread < ctrl[0]) ||
+		    ((dbz2err != BZ_OK) && (dbz2err != BZ_STREAM_END)))
+			errx(1, "Corrupt patch\n");
+
+		/* Add old data to diff string */
+		for(i=0;i<ctrl[0];i++)
+			if((oldpos+i>=0) && (oldpos+i<oldsize))
+				new[newpos+i]+=old[oldpos+i];
+
+		/* Adjust pointers */
+		newpos+=ctrl[0];
+		oldpos+=ctrl[0];
+
+		/* Sanity-check */
+		if(newpos+ctrl[1]>newsize)
+			errx(1,"Corrupt patch\n");
+
+		/* Read extra string */
+		lenread = BZ2_bzRead(&ebz2err, epfbz2, new + newpos, ctrl[1]);
+		if ((lenread < ctrl[1]) ||
+		    ((ebz2err != BZ_OK) && (ebz2err != BZ_STREAM_END)))
+			errx(1, "Corrupt patch\n");
+
+		/* Adjust pointers */
+		newpos+=ctrl[1];
+		oldpos+=ctrl[2];
+	};
+
+	/* Clean up the bzip2 reads */
+	BZ2_bzReadClose(&cbz2err, cpfbz2);
+	BZ2_bzReadClose(&dbz2err, dpfbz2);
+	BZ2_bzReadClose(&ebz2err, epfbz2);
+	if (fclose(cpf) || fclose(dpf) || fclose(epf))
+		err(1, "fclose(%s)", argv[3]);
+
+	/* Write the new file */
+	if(((fd=open(argv[2],O_CREAT|O_TRUNC|O_WRONLY,0666))<0) ||
+		(write(fd,new,newsize)!=newsize) || (close(fd)==-1))
+		err(1,"%s",argv[2]);
+
+	free(new);
+	free(old);
+
+	return 0;
+}
diff --git a/src/libutil/hash.hh b/src/libutil/hash.hh
index 0a0dfed7e..97466cf9e 100644
--- a/src/libutil/hash.hh
+++ b/src/libutil/hash.hh
@@ -66,7 +66,7 @@ Hash hashString(HashType ht, const string & s);
 Hash hashFile(HashType ht, const Path & path);
 
 /* Compute the hash of the given path.  The hash is defined as
-   md5(dump(path)). */
+   (essentially) hashString(ht, dumpPath(path)). */
 Hash hashPath(HashType ht, const Path & path);
 
 /* Compress a hash to the specified number of bytes by cyclically
diff --git a/substitute.mk b/substitute.mk
index 5f9204929..2b7f38610 100644
--- a/substitute.mk
+++ b/substitute.mk
@@ -11,8 +11,8 @@
 	 -e "s^@system\@^$(system)^g" \
 	 -e "s^@shell\@^$(shell)^g" \
 	 -e "s^@curl\@^$(curl)^g" \
-	 -e "s^@bzip2\@^$(bzip2)^g" \
-	 -e "s^@bunzip2\@^$(bunzip2)^g" \
+	 -e "s^@bzip2\@^$(bzip2_bin)/bzip2^g" \
+	 -e "s^@bunzip2\@^$(bzip2_bin)/bunzip2^g" \
 	 -e "s^@perl\@^$(perl)^g" \
 	 -e "s^@coreutils\@^$(coreutils)^g" \
 	 -e "s^@tar\@^$(tar)^g" \