Privoxy

https://www.privoxy.org/
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### Setup Debian Build Environment

Source: https://www.privoxy.org/developer-manual/newrelease.html

Install necessary build tools and dependencies.

```bash
  sudo apt install build-essential devscripts
  sudo apt-get build-dep privoxy
```

```bash
  dpkg-checkbuilddeps
```

```bash
  sudo apt install foobar
```

--------------------------------

### Build and Install Privoxy

Source: https://www.privoxy.org/user-manual/installation.html

Standard sequence of commands to configure, build, and install the software.

```bash
  autoheader
  autoconf
  ./configure      # (--help to see options)
  make             # (the make from GNU, sometimes called gmake)
  su               # Possibly required
  make -n install  # (to see where all the files will go)
  make -s install  # (to really install, -s to silence output)
```

--------------------------------

### Start Privoxy on Debian

Source: https://www.privoxy.org/user-manual/startup.html

Use the init script to start the Privoxy service on Debian systems.

```bash
  # /etc/init.d/privoxy start
```

--------------------------------

### Start Privoxy on FreeBSD and ElectroBSD

Source: https://www.privoxy.org/user-manual/startup.html

Manually start the Privoxy service using the service command.

```bash
  # service privoxy onestart
```

--------------------------------

### Start Privoxy on Unix Derivatives

Source: https://www.privoxy.org/user-manual/startup.html

Manually start Privoxy by specifying the user and configuration file path.

```bash
  # /usr/sbin/privoxy --user privoxy /etc/privoxy/config
```

--------------------------------

### Path Pattern Examples

Source: https://www.privoxy.org/user-manual/actions-file.html

Examples of POSIX regular expressions used for matching URL paths in Privoxy configuration.

```text
.example.com/.*
```

```text
.example.com/.*/index.html$
```

```text
.example.com/(.*/)?index\.html$
```

```text
.example.com/(.*/)(ads|banners?|junk)
```

```text
.example.com/(.*/)(ads|banners?|junk)/.*\.(jpe?g|gif|png)$
```

--------------------------------

### Install with User Ownership

Source: https://www.privoxy.org/user-manual/installation.html

Specify the user and group ownership for configuration files during the installation process.

```bash
  make -s install  USER=privoxy GROUP=privoxy
```

--------------------------------

### Configure with Custom Flags

Source: https://www.privoxy.org/user-manual/installation.html

Example of setting environment variables before running the configure script.

```bash
  $ export CFLAGS="-O2"              # set gcc optimization level
  $ export LDFLAGS="-Wl,--nxcompat"  # Enable DEP
  $ ./configure --host=i686-w64-mingw32 --enable-mingw32  --enable-zlib \
  >             --enable-static-linking --disable-pthread
  $ make                             # build Privoxy
```

--------------------------------

### Sign Windows Release Files

Source: https://www.privoxy.org/developer-manual/newrelease.html

GPG sign the installer and zip files before uploading.

```bash
  gpg --armor --detach --sign `privoxy_setup_X.Y.Z.exe`
  gpg --armor --detach --sign `privoxy_X.Y.Z.zip`
```

--------------------------------

### Configure System User

Source: https://www.privoxy.org/user-manual/installation.html

Example entries for system configuration files to define a dedicated unprivileged user for Privoxy.

```text
  privoxy:*:7777:7777:privoxy proxy:/no/home:/no/shell
```

```text
  privoxy:*:7777:
```

--------------------------------

### Configure Language and User Agent

Source: https://www.privoxy.org/user-manual/actions-file.html

Example of setting custom Accept-Language and User-Agent headers for a specific path.

```text
# Pretend to use Canadian language settings.
  {+hide-accept-language{en-ca} \
  +hide-user-agent{Mozilla/5.0 (X11; U; OpenBSD i386; en-CA; rv:1.8.0.4) Gecko/20060628 Firefox/1.5.0.4} \
  }
  /
```

--------------------------------

### Compression and Filter Configuration

Source: https://www.privoxy.org/user-manual/actions-file.html

Example of applying filters and compression settings to specific domains or globally.

```text
# Selectively turn off compression, and enable a filter
#
{ +filter{tiny-textforms} +prevent-compression }
# Match only these sites
.google.
sourceforge.net
sf.net

# Or instead, we could set a universal default:
#
{ +prevent-compression }
/ # Match all sites

# Then maybe make exceptions for broken sites:
#
{ -prevent-compression }
.compusa.com/
```

--------------------------------

### Configure Forwarding Rules

Source: https://www.privoxy.org/user-manual/config.html

Examples demonstrating how to route traffic through parent proxies or bypass them for specific domains and protocols.

```text
  forward   /      parent-proxy.example.org:8080
  forward   :443   .
```

```text
  forward   /                  caching-proxy.isp.example.net:8000
  forward   .isp.example.net   .
```

```text
  forward   /                   [2001:DB8::1]:8000
```

```text
  forward  /                        parent-proxy.example.org:8000
  forward  ipv6-server.example.org  .
  forward  <[2-3][0-9a-f][0-9a-f][0-9a-f]:*>   .
```

--------------------------------

### Configure hide-referrer action

Source: https://www.privoxy.org/user-manual/actions-file.html

Examples of forging or setting a custom Referer header.

```Privoxy Configuration
+hide-referrer{forge}
```

```Privoxy Configuration
+hide-referrer{http://www.yahoo.com/}
```

--------------------------------

### Inspect URL Action Matches

Source: https://www.privoxy.org/user-manual/appendix.html

Example output from the Privoxy show-url-info page showing how default and custom actions are applied to a specific domain.

```text
  Matches for http://www.google.com:

  In file: default.action [ View ] [ Edit ]

  {+change-x-forwarded-for{block}
   +deanimate-gifs {last}
   +fast-redirects {check-decoded-url}
   +filter {refresh-tags}
   +filter {img-reorder}
   +filter {banners-by-size}
   +filter {webbugs}
   +filter {jumping-windows}
   +hide-from-header {block}
   +hide-referrer {forge}
   +session-cookies-only
   +set-image-blocker {pattern} }
  /

  { -session-cookies-only }
  .google.com

  { -fast-redirects }
  .google.com

  In file: user.action [ View ] [ Edit ]
  (no matches in this file)
```

--------------------------------

### Configure hide-from-header action

Source: https://www.privoxy.org/user-manual/actions-file.html

Examples of removing or replacing the From HTTP header.

```Privoxy Configuration
+hide-from-header{block}
```

```Privoxy Configuration
+hide-from-header{spam-me-senseless@sittingduck.example.com}
```

--------------------------------

### Defining Action Sections

Source: https://www.privoxy.org/user-manual/actions-file.html

Example of a regular action section applying multiple actions to specific URL patterns.

```text
  { +`handle-as-image`  +`block{Banner ads.}` }
  # Block these as if they were images. Send no block page.
  banners.example.com
  media.example.com/.*banners
  .example.com/images/ads/
```

--------------------------------

### Set global image blocker

Source: https://www.privoxy.org/user-manual/actions-file.html

Configure the default image blocking behavior for all sites. This example sets the blocker to display a blank image instead of a checkerboard pattern.

```text
{ +set-image-blocker{blank} }
/ # ALL sites
```

--------------------------------

### Configure hide-user-agent action

Source: https://www.privoxy.org/user-manual/actions-file.html

Example of setting a custom User-Agent string to conceal browser and OS information.

```Privoxy Configuration
+hide-user-agent{Mozilla/5.0 (X11; ElectroBSD i386; rv:78.0) Gecko/20100101 Firefox/78.0}
```

--------------------------------

### Perform a merge-free Git workflow

Source: https://www.privoxy.org/developer-manual/git.html

Example session demonstrating how to create a local branch, commit changes, and rebase onto the master branch to maintain a clean history.

```bash
  fk@t520 ~/git/privoxy $git checkout master
  Switched to branch 'master'
  Your branch is up to date with 'origin/master'.
  # Make sure you have the latest changes
  fk@t520 ~/git/privoxy $git pull
  Already up to date.
  # Create a local banch for changes
  fk@t520 ~/git/privoxy $git checkout -b local-branch
  Switched to a new branch 'local-branch'
  # Create some change
  fk@t520 ~/git/privoxy $gmake dok dok-tidy
  [...]
  # Review your change
  fk@t520 ~/git/privoxy $git diff
  [...]
  # Commit your changes if they look goood
  fk@t520 ~/git/privoxy $git commit -m "developer-manual: Regenerate" doc/webserver/
  [local-branch 1abb7316] developer-manual: Regenerate
   1 file changed, 2 insertions(+), 2 deletions(-)
  # Review your commit
  fk@t520 ~/git/privoxy $git show
  [...]
  # Go to the master branch
  fk@t520 ~/git/privoxy $git checkout master
  Switched to branch 'master'
  Your branch is up to date with 'origin/master'.
  # Make sure you are still in sync
  fk@t520 ~/git/privoxy $git pull
  [...]
  Already up to date.
  # Apply the commit you made to the local-branch
  fk@t520 ~/git/privoxy $git cherry-pick local-branch
  [master 046e85e2] developer-manual: Regenerate
   Date: Tue Dec 15 05:10:07 2020 +0100
   1 file changed, 2 insertions(+), 2 deletions(-)
  # Make sure the history looks as expected
  fk@t520 ~/git/privoxy $git log -p
  # Finally push your change to the Privoxy repository
  fk@t520 ~/git/privoxy $git push
  [...]
  # Go back to the local branch
  fk@t520 ~/git/privoxy $git checkout local-branch
  # Rebase on top of master and continue hacking
  fk@t520 ~/git/privoxy $git rebase master
  Successfully rebased and updated refs/heads/local-branch.
```

--------------------------------

### Redirecting Requests with Privoxy Actions

Source: https://www.privoxy.org/user-manual/actions-file.html

Examples of using the redirect action to map old URLs to new locations or local configurations.

```text
# Redirect requests for the old Tor Hidden Service of the Privoxy website to the new one
{+redirect{s@^http://jvauzb4sb3bwlsnc.onion/@http://privoxy5wtwbtk4wwyrdbg6oxeghvhghghmokcx2iawydkqmaztfbbid.onion/@}}
jvauzb4sb3bwlsnc.onion/

# Redirect remote requests for this manual
# to the local version delivered by Privoxy
{+redirect{s@^http://www@http://config@}}
www.privoxy.org/user-manual/
```

--------------------------------

### Automated Build

Source: https://www.privoxy.org/user-manual/installation.html

Use the make command to automatically execute the initial configuration and build steps.

```bash
  make
```

--------------------------------

### Configuring the source build

Source: https://www.privoxy.org/developer-manual/newrelease.html

Prepare the build environment by generating configuration scripts from a clean source directory.

```bash
  autoheader && autoconf && ./configure
```

--------------------------------

### Upload to Webserver

Source: https://www.privoxy.org/developer-manual/webserver-update.html

Uploads documentation to the SourceForge webserver and sets correct file permissions. Use only this method to avoid permission issues.

```bash
  make webserver
```

--------------------------------

### Rebuild Documentation

Source: https://www.privoxy.org/developer-manual/newrelease.html

Execute these make targets to rebuild the man pages, configuration files, and general documentation.

```bash
  $ make man
  $ make dok
  $ make dok-man
  $ make dok-tidy
  $ make config-file
```

--------------------------------

### Common Configure Options

Source: https://www.privoxy.org/user-manual/installation.html

Standard configuration flags for native Windows builds under Cygwin.

```bash
  --host=i686-w64-mingw32
  --enable-mingw32
  --enable-zlib
  --enable-static-linking
  --disable-pthread
  --with-brotli
  --with-mbedtls
```

--------------------------------

### Define block action with reason

Source: https://www.privoxy.org/user-manual/appendix.html

Example of a block action that includes a descriptive reason for the block.

```text
  { +block{Path starts with "ads".} +handle-as-image }
  /ads
```

--------------------------------

### Disable Content-Disposition Header

Source: https://www.privoxy.org/user-manual/actions-file.html

Example of using hide-content-disposition to prevent forced downloads on specific domains.

```text
# Disarm the download link in Sourceforge's patch tracker
  { -filter \
    +content-type-overwrite{text/plain} \
    +hide-content-disposition{block} \
  }
  .sourceforge.net/tracker/download\.php
```

--------------------------------

### Disable Pop-up Filters for Specific Domains

Source: https://www.privoxy.org/user-manual/actions-file.html

Example configuration to disable pop-up filtering for specific e-commerce domains.

```text
  # These shops require pop-ups:
  #
  {-filter{all-popups} -filter{unsolicited-popups}}
  .dabs.com
  .overclockers.co.uk
```

--------------------------------

### Run Privoxy config as administrator on Windows

Source: https://www.privoxy.org/faq/trouble.html

Use the runas command to open the configuration file with elevated privileges.

```cmd
  runas /user:administrator "notepad \privoxy\config.txt"
```

--------------------------------

### Request Tag Pattern Syntax

Source: https://www.privoxy.org/user-manual/actions-file.html

Examples of patterns used to match request tags, which must be prefixed with TAG:.

```text
TAG:^foo$
```

```text
TAG:foo
```

```text
TAG: foo
```

--------------------------------

### Configure the configuration directory

Source: https://www.privoxy.org/user-manual/config.html

Sets the base directory for Privoxy configuration files.

```text
confdir /etc/privoxy
```

--------------------------------

### Build and Test Debian Package

Source: https://www.privoxy.org/developer-manual/newrelease.html

Build the package and verify it using lintian, cowbuilder, and autopkgtest.

```bash
  gbp buildpackage -us -uc
```

```bash
  lintian -iI ../build-area/privoxy_4.2.0-1_amd64.changes
```

```bash
  sudo cowbuilder --build --basepath /var/cache/pbuilder/base.cow ../build-area/privoxy_4.2.0-1.dsc
```

```bash
  autopkgtest /var/cache/pbuilder/result/privoxy_4.2.0-1_amd64.changes -s -- schroot sid
```

--------------------------------

### Standard GNU Autotools Build Process

Source: https://www.privoxy.org/user-manual/installation.html

General workflow for building software using GNU Autotools.

```bash
  autoheader              # creates config.h.in
  autoconf                # uses config.h.in to create the configure shell script
  ./configure [options]   # creates GNUmakefile
  make        [options]   # builds the program
```

--------------------------------

### Avoid redundant or inaccurate comments

Source: https://www.privoxy.org/developer-manual/coding.html

Examples of comments that either state the obvious or contradict the actual logic of the code.

```c
  /* if page size greater than 1k ... */
  if (page_length() > 1024)
  {
      ... "block" the page up ...
  }

  /* if page size is small, send it in blocks */
  if (page_length() > 1024)
  {
      ... "block" the page up ...
  }
```

--------------------------------

### Generate Documentation

Source: https://www.privoxy.org/developer-manual/webserver-update.html

Generates documentation files from SGML sources. Run this after modifying stable-branch documentation.

```bash
  make dok && make dok-tidy
```

--------------------------------

### Configure header modification for tracking protection

Source: https://www.privoxy.org/user-manual/actions-file.html

Example of combining multiple header modification actions to reduce tracking.

```Privoxy Configuration
{+hide-if-modified-since{-60} \
   +overwrite-last-modified{randomize} \
   +crunch-if-none-match}
  /
```

--------------------------------

### Build Windows Package

Source: https://www.privoxy.org/developer-manual/newrelease.html

Execute the build process within the windows directory.

```bash
  cd windows
  make
```

--------------------------------

### Define a content filter header

Source: https://www.privoxy.org/user-manual/filter-file.html

Example of a header line for a content filter named 'foo' that replaces 'foo' with 'bar'.

```text
  FILTER: foo Replace all "foo" with "bar"
```

--------------------------------

### Define Client Tags in Configuration

Source: https://www.privoxy.org/user-manual/howto.html

Register tag names and descriptions in the Privoxy configuration file to make them available for use.

```text
  client-specific-tag tor Use Tor anonymous proxy
  client-specific-tag https-inspection Enable https-inspection
```

--------------------------------

### Block Content Actions

Source: https://www.privoxy.org/user-manual/actions-file.html

Examples of blocking content with different replacement strategies, such as showing a block page, an image, or an empty document.

```text
{+block{No nasty stuff for you.}}
# Block and replace with "blocked" page
.nasty-stuff.example.com

{+block{Doubleclick banners.} +handle-as-image}
# Block and replace with image
.ad.doubleclick.net
.ads.r.us/banners/

{+block{Layered ads.} +handle-as-empty-document}
# Block and then ignore
adserver.example.net/.*\.js$
```

--------------------------------

### Tagging and Filtering Requests

Source: https://www.privoxy.org/user-manual/actions-file.html

Examples of using server-header taggers to identify content types and applying external filters based on tags.

```Privoxy Configuration
# Tag every request with the content type declared by the server
{+server-header-tagger{content-type}}
/

# If the response has a tag starting with 'image/' enable an external
# filter that only applies to images.
#
# Note that the filter is not available by default, it's just a
# `silly example`.
{+external-filter{rotate-image} +force-text-mode}
TAG:^image/
```

--------------------------------

### Clone Debian Repository

Source: https://www.privoxy.org/developer-manual/newrelease.html

Initialize or update the local Debian repository using gbp.

```bash
  gbp clone https://salsa.debian.org/debian/privoxy.git
  cd privoxy
```

```bash
  cd privoxy
  gbp pull
```

--------------------------------

### Define external filters in Privoxy

Source: https://www.privoxy.org/user-manual/filter-file.html

Examples of defining external filters using the EXTERNAL-FILTER directive. These filters can be simple commands or shell scripts.

```text
  EXTERNAL-FILTER: cat Pointless example filter that doesn't actually modify the content
  /bin/cat

  # Incorrect reimplementation of the filter above in POSIX shell.
  #
  # Note that it's a single job that spans multiple lines, the line
  # breaks are not passed to the shell, thus the semicolons are required.
  #
  # If the script isn't trivial, it is recommended to put it into an external file.
  #
  # In general, writing external filters entirely in POSIX shell is not
  # considered a good idea.
  EXTERNAL-FILTER: cat2 Pointless example filter that despite its name may actually modify the content
  while read line; \
  do \
    echo "$line"; \
  done

  EXTERNAL-FILTER: rotate-image Rotate an image by 180 degree. Test filter with limited value.
  /usr/local/bin/convert - -rotate 180 -

  EXTERNAL-FILTER: citation-needed Adds a "[citation needed]" tag to an image. The coordinates may need adjustment.
  /usr/local/bin/convert - -pointsize 16 -fill white  -annotate +17+418 "[citation needed]" -
```

--------------------------------

### Build Privoxy Executable

Source: https://www.privoxy.org/user-manual/installation.html

Command to build the Privoxy executable directly.

```bash
  cd <root-dir>/privoxy
  ./windows/MYconfigure && make
```

--------------------------------

### Include Header Files

Source: https://www.privoxy.org/developer-manual/coding.html

Use local paths for project headers and avoid absolute paths unless necessary for system headers.

```c
  #include <iostream.h>     /* This is not a local include */
  #include "config.h"       /* This IS a local include */
```

```c
  /* This is not a local include, but requires a path element. */
  #include <sys/fileName.h>
```

--------------------------------

### Tagging and Forwarding Overrides

Source: https://www.privoxy.org/user-manual/actions-file.html

Examples of using client-header-tagger to identify specific user agents or request types and applying conditional forwarding or header modifications.

```Privoxy Configuration
# Tag every request with the User-Agent header
{+client-header-tagger{user-agent}}
/

# Tagging itself doesn't change the action
# settings, sections with TAG patterns do:
#
# If it's a download agent, use a different forwarding proxy,
# show the real User-Agent and make sure resume works.
{+forward-override{forward-socks5 10.0.0.2:2222 .} \
 -hide-if-modified-since      \
 -overwrite-last-modified     \
 -hide-user-agent             \
 -filter                      \
 -deanimate-gifs              \
}
TAG:^User-Agent: NetBSD-ftp/
TAG:^User-Agent: Novell ZYPP Installer
TAG:^User-Agent: RPM APT-HTTP/
TAG:^User-Agent: fetch libfetch/
TAG:^User-Agent: Ubuntu APT-HTTP/
TAG:^User-Agent: MPlayer/
```

```Privoxy Configuration
# Tag all requests with the Range header set
{+client-header-tagger{range-requests}}
/

# Disable filtering for the tagged requests.
#
# With filtering enabled Privoxy would remove the Range headers
# to be able to filter the whole response. The downside is that
# it prevents clients from resuming downloads or skipping over
# parts of multimedia files.
{-filter -deanimate-gifs}
TAG:^RANGE-REQUEST$
```

```Privoxy Configuration
# Tag all requests with the client IP address
#
# (Technically the client IP address isn't included in the
# client headers but client-header taggers can set it anyway.
# For details see the tagger in default.filter)
{+client-header-tagger{client-ip-address}}
/

# Change forwarding settings for requests coming from address 10.0.0.1
{+forward-override{forward-socks5 127.0.1.2:2222 .}}
TAG:^IP-ADDRESS: 10\.0\.0\.1$
```

--------------------------------

### Build Debian Snapshot

Source: https://www.privoxy.org/developer-manual/newrelease.html

Update changelog and build the package from the git tree.

```bash
  dch
```

```bash
  debuild -us -uc -b
```

--------------------------------

### Define Global Default Actions

Source: https://www.privoxy.org/user-manual/actions-file.html

Configuration for match-all.action to set default behavior for all URLs using line continuation.

```text
  { \
   +change-x-forwarded-for{block} \
   +hide-from-header{block} \
   +set-image-blocker{pattern} \
  }
  / # Match all URLs
```

--------------------------------

### Build Tidy HTML5

Source: https://www.privoxy.org/user-manual/installation.html

Steps to build the Tidy library required for documentation generation.

```bash
  cd <root-dir>
  cd tidy-html5-x.y.z/build/cmake
  cmake ../.. -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIB:BOOL=OFF -DCMAKE_INSTALL_PREFIX=/usr/local
  make && make install
```

--------------------------------

### Configure the user-manual location

Source: https://www.privoxy.org/user-manual/config.html

Defines the URI for the Privoxy User Manual. This should be the first option in the configuration file.

```text
  user-manual  /usr/share/doc/privoxy/user-manual
```

```text
  user-manual  http://example.com/privoxy/user-manual/
```

--------------------------------

### Clone Privoxy Source Code

Source: https://www.privoxy.org/user-manual/installation.html

Commands to create a root directory and clone the Privoxy repository.

```bash
  mkdir <root-dir>
  cd <root-dir>
  git clone https://www.privoxy.org/git/privoxy.git
```

--------------------------------

### Creating the source tarball

Source: https://www.privoxy.org/developer-manual/newrelease.html

Execute the make target to generate the distribution tarball after configuration.

```bash
  make tarball-dist
```

--------------------------------

### Rebuild configuration and documentation

Source: https://www.privoxy.org/developer-manual/newrelease.html

Commands used to update build files and documentation after incrementing the version number.

```bash
autoheader && autoconf
```

```bash
./configure
```

```bash
make dok-release
```

--------------------------------

### Generate Privoxy CA Certificate and Key

Source: https://www.privoxy.org/user-manual/howto.html

Use OpenSSL to create the private key and certificate for the Privoxy CA.

```bash
  openssl req -new -x509 -extensions v3_ca -keyout privoxy.pem -out privoxy.crt -days 3650
```

--------------------------------

### Define header file prototypes

Source: https://www.privoxy.org/developer-manual/coding.html

Use descriptive parameter names in header file prototypes that match the implementation in the .c file.

```C
  (.h) extern int load_aclfile(struct client_state *csp);
  (.c) int load_aclfile(struct client_state *csp)
```

```C
  (.h) extern int load_aclfile(struct client_state *); or
  (.h) extern int load_aclfile();
  (.c) int load_aclfile(struct client_state *csp)
```

--------------------------------

### Build Brotli Library

Source: https://www.privoxy.org/user-manual/installation.html

Compilation commands for the static Brotli library.

```bash
  ./bootstrap
  #  to create the GNU autotools files

  autoconf

  export CFLAGS="-O2 -fstack-protector-strong -D_FORTIFY_SOURCE=2"
  export LDFLAGS="${LDFLAGS} -fstack-protector-strong"

  ./configure  --host=i686-w64-mingw32 \
               --prefix=/usr/local/i686-w64-mingw32 \
               --enable-static   \
               --disable-shared  \
               --with-gnu-ld     \
               --disable-silent-rules \
    && make
```

--------------------------------

### Configure and run Privoxy for fuzzing

Source: https://www.privoxy.org/developer-manual/testing.html

Commands to compile Privoxy with instrumentation and execute it in fuzzing mode.

```bash
  # Compile Privoxy with instrumentation for afl
  $ export CC=afl-clang
  $ export CFLAGS="-fsanitize=address -ggdb"
  $ export CPPFLAGS=-I/usr/local/include/
  $ export LDFLAGS="-fsanitize=address -L/usr/local/lib"
  $ export AFL_USE_ASAN=1
  $ export AFL_HARDEN=1
  $ ./configure --with-debug --enable-extended-host-patterns --enable-accept-filter --enable-no-gifs --enable-compression --enable-strptime-sanity-checks --enable-external-filters --enable-fuzz

  $ ./privoxy --fuzz
  Privoxy version 3.0.24 (http://www.privoxy.org/)
  Usage: ./privoxy [--config-test] [--chroot] [--help] [--no-daemon] [--pidfile pidfile] [--pre-chroot-nslookup hostname] [--user user[.group]] [--version] [configfile]
         ./privoxy --fuzz fuzz-mode ./path/to/fuzzed/input [--stfu]

  Supported fuzz modes and the expected input:
   action: Text to parse as action file.
   client-request: Client request to parse. Currently incomplete
   client-header: Client header to parse.
   chunked-transfer-encoding: Chunk-encoded data to dechunk.
   deflate: deflate-compressed data to decompress.
   filter: Text to parse as filter file.
   gif: gif to deanimate.
   gzip: gzip-compressed data to decompress.
   pcrs-substitute: A pcrs-substitute to compile. Not a whole pcrs job! Example: Bla $1 bla C $3 blah.
   server-header: Server header to parse.
   server-response: Server response to parse.

  The following fuzz modes read data from stdin if the 'file' is '-'
   client-request
   client-header
   chunked-transfer-encoding
   deflate
   gif
   gzip
   pcrs-substitute
   server-header
   server-response

  Aborting

  $ export ASAN_OPTIONS='abort_on_error=1'
  $ mkdir input output
  $ echo '$1 bla fasel $2' > input/pcrs
  $ afl-fuzz -i input -o output -m none ~/git/privoxy/privoxy --fuzz pcrs-substitute - --stfu

  $ cat >input/pcrs.txt
  FILTER: bla fasel
  s@(.{1})[432](\d+)@$1$2$hostname@UgisT

  $ afl-fuzz -i input/ -o output/ -f bla.filter -m none privoxy --fuzz filter bla.filter --stfu
```

--------------------------------

### Enable Debugging Options

Source: https://www.privoxy.org/faq/contact.html

Configuration directive to enable detailed logging for troubleshooting requests.

```text
debug 1 # Log the destination for each request. See also debug 1024.
```

--------------------------------

### Configure Localhost Exception

Source: https://www.privoxy.org/faq/misc.html

Add this exception to allow the browser to resolve and reach local network servers by name.

```text
  #        forward           localhost/     .
```

--------------------------------

### Rebuild Configuration Files

Source: https://www.privoxy.org/developer-manual/newrelease.html

Use these commands to regenerate the configure script and GNUmakefile after updating version status.

```bash
  $ autoheader && autoconf     # rebuild configure
  $ ./configure                # rebuild GNUmakefile
```
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