From 7822f664b94255470dcb4edcd866953ec4fd9c3f Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Jesu=CC=81s=20Gonza=CC=81lez?= Date: Fri, 4 Nov 2022 16:55:33 +0100 Subject: [PATCH] feat: Adding mod_wasm --- docs/manual/mod/allmodules.xml | 1 + docs/manual/mod/mod_wasm.html | 5 + docs/manual/mod/mod_wasm.html.en | 332 +++++++++++++++++ docs/manual/mod/mod_wasm.xml | 326 ++++++++++++++++ docs/manual/mod/mod_wasm.xml.meta | 12 + modules/wasm/Makefile.in | 16 + modules/wasm/config.m4 | 150 ++++++++ modules/wasm/mod_wasm.c | 598 ++++++++++++++++++++++++++++++ 8 files changed, 1440 insertions(+) create mode 100644 docs/manual/mod/mod_wasm.html create mode 100644 docs/manual/mod/mod_wasm.html.en create mode 100644 docs/manual/mod/mod_wasm.xml create mode 100644 docs/manual/mod/mod_wasm.xml.meta create mode 100644 modules/wasm/Makefile.in create mode 100644 modules/wasm/config.m4 create mode 100644 modules/wasm/mod_wasm.c diff --git a/docs/manual/mod/allmodules.xml b/docs/manual/mod/allmodules.xml index fb0599b4f8..c523861ccb 100644 --- a/docs/manual/mod/allmodules.xml +++ b/docs/manual/mod/allmodules.xml @@ -133,6 +133,7 @@ mod_usertrack.xml mod_version.xml mod_vhost_alias.xml + mod_wasm.xml mod_watchdog.xml mod_xml2enc.xml mpm_common.xml diff --git a/docs/manual/mod/mod_wasm.html b/docs/manual/mod/mod_wasm.html new file mode 100644 index 0000000000..e3f1f13dba --- /dev/null +++ b/docs/manual/mod/mod_wasm.html @@ -0,0 +1,5 @@ +# GENERATED FROM XML -- DO NOT EDIT + +URI: mod_wasm.html.en +Content-Language: en +Content-type: text/html; charset=UTF-8 diff --git a/docs/manual/mod/mod_wasm.html.en b/docs/manual/mod/mod_wasm.html.en new file mode 100644 index 0000000000..f9b7946746 --- /dev/null +++ b/docs/manual/mod/mod_wasm.html.en @@ -0,0 +1,332 @@ + + + + + +mod_wasm - Apache HTTP Server Version 2.4 + + + + + + + +
+

Modules | Directives | FAQ | Glossary | Sitemap

+

Apache HTTP Server Version 2.4

+
+
<-
+
+Apache > HTTP Server > Documentation > Version 2.4 > Modules
+
+

Apache Module mod_wasm

+
+

Available Languages:  en 

+
+ + + + +
Description:Runs Wasm modules via Wasmtime engine +
Status:Experimental
Module Identifier:wasm_module
Source File:mod_wasm.c
Compatibility:Available in version 2.4.x and later
+

Summary

+ +

+ mod_wasm offers a secure enclave to run untrusted 3rd party software. + It allows WebAssembly (Wasm) modules to be executed within the Apache Server. + Code runs in a secure environment at almost native speed. + The Wasm Capabilities Model offers a secure-by-design approach to limit access to system resources. + No capabilities are enabled by default. To enable such capabilities, new directives are provided for httpd.conf. +

+ mod_wasm, being written in C, uses the library libwasm_runtime.so to interact with the Wasm engine + Wasmtime, both written in Rust. + This provides additional guarantees regarding security, memory safety, and performance. + Another module following a similar design is mod_tls. +

+ WebAssembly is a portable binary code. Therefore, developers can write programs in + their favorite programming language (C, C++, C#, Rust, Go, Swift, etc.) + and target Wasm format as the output (in the same way you can target x86_64 or aarch64). + In addition, a language runtime written in a supported language can be compiled + into Wasm (i.e.: PHP, Python, Ruby, Perl, all written in C). + And then, run their interpreters within the secure environment that mod_wasm provides. +

+ mod_wasm implements a content handler that captures the stdout from the Wasm binary, and then it is appended to the HTTP request response. +

+
+ +
top
+
+

Minimal Configuration: Running a Wasm Module

+ +

+ Below is a minimal configuration sample of the directives needed in httpd.conf to use mod_wasm. +

+ Just set the wasm-handler to the desired route, and point to a Wasm module via WasmRoot and WasmModule. +

+ 
LoadModule wasm_module modules/mod_wasm.so
+
+<Location /wasm-module>
+  SetHandler wasm-handler
+</Location>
+
+<IfModule wasm_module>
+  WasmRoot   /var/www/wasm_modules
+  WasmModule hello.wasm
+</IfModule>
+ +
top
+
+

Advanced Configuration: Running a Python-based WebApp

+ +

+ Below is an advanced configuration for running a Python-based webapp within mod_wasm. +

+ The Python language runtime is in Wasm binary format. The Python script to be run is passed as an argument via WasmArg. +

+ Python runtime requires both PYTHONHOME and PYTHONPATH environment variables + to be set and point to a directory containing the Python standard library. This can be done using + WasmEnv. +

+ Also, such directories must be pre-opened and available in the Wasm context via WasmDir or WasmMapDir. +

+ Finally, CGI mode is activated using WasmEnableCGI. + This way, HTTP headers and URL parameters from the incoming request are passed to the Wasm module + as environmental variables. In this mode, it is expected that responses from the Wasm module + start with the HTTP response header (i.e.: Content-Type: text/html). +

+ 
LoadModule wasm_module modules/mod_wasm.so
+
+<Location /wasm-module>
+  SetHandler wasm-handler
+</Location>
+
+<IfModule wasm_module>
+  WasmRoot   	/var/www/wasm_modules
+  WasmModule 	python3.11.wasm
+  WasmMapDir 	/python /usr/lib/python3.11
+  WasmArg	 	/python/hello.py
+  WasmEnv	 	PYTHONHOME /python/wasi-python/lib/python3.11
+  WasmEnv	 	PYTHONPATH /python/wasi-python/lib/python3.11
+  WasmEnableCGI On
+</IfModule>
+ +
top
+
+

mod_wasm Directives Index

+ +

+ The table below provides a comprehensive list of all directives provided by mod_wasm. +

+ + + + + + + + + +
Directive
WasmRoot
WasmModule
WasmDir
WasmMapDir
WasmArg
WasmEnv
WasmEnableCGI
+

+

+
+
top
+

WasmArg Directive

+ + + + + + +
Description:Set an argument to be passed to the Wasm module context.
Syntax:WasmArg argument
Context:server config
Status:Experimental
Module:mod_wasm
+

+ WasmArg is related to the well-known argv parameter in the C int main (int argc, *argv[]) function declaration. +

+ This directive allows passing different arguments to the Wasm module as its main function + was invoked with such an argument. +

+ This directive can be used as many times as needed, but only one argument per directive. +

+ The order is accumulative, this is, the first invocation will become the first argument, and so on. +

+

Example

WasmArg /my-site/scripts/hello.py
+WasmArg --effusive-mode
+
+ +
+
top
+

WasmDir Directive

+ + + + + + +
Description:Pre-open a host directory for the Wasm context.
Syntax:WasmDir directory
Context:server config
Status:Experimental
Module:mod_wasm
+

+ WasmDir pre-opens a directory in the host system to be available in the Wasm context. +

+ This is a security feature from the Wasm Capabilities Model, + in which no directory in the host filesystem is available in the Wasm module context unless is explicitly pre-opened. +

+ This directive can be used as many times as needed, but only one directory per directive. +

+

Example

WasmDir /var/www/assets/common
+WasmDir /var/www/htdocs/my-site
+
+ +
+
top
+

WasmEnableCGI Directive

+ + + + + + +
Description:Enable/Disable CGI emulation mode for HTTP headers.
Syntax:WasmEnableCGI On|Off
Context:server config
Status:Experimental
Module:mod_wasm
+

+ WasmEnableCGI allows mod_wasm to connect the HTTP requests with the Wasm module in a CGI-like way: +

    +
  • HTTP headers from the request are passed to the Wasm module as environmental variables.
    • +
  • URL query parameters are passed as QUERY_STRING environmental variable.
    • +
  • Output from the Wasm module (stdout) will be parsed and headers such as Content-Type: will be + incorporated into the response headers.
    • +
+ Default value is Off. +

+

Example

WasmEnableCGI On
+
+

+ HTTP request headers are prefixed with 'HTTP_', uppercased, and hyphens '-' are substituted by underscores '_' when transformed into environmental variables. +

+ As an example, a header like x-custom-header: value will be transformed into an HTTP_X_CUSTOM_HEADER=value environmental variable. +

+ +
+
top
+

WasmEnv Directive

+ + + + + + +
Description:Set an environment variable to be passed to the Wasm module context.
Syntax:WasmEnv variable_name variable_value
Context:server config
Status:Experimental
Module:mod_wasm
+

+ WasmEnv allows setting environment variables within the Wasm module context. +

+ This directive can be used as many times as needed, but only one tuple variable_name variable_value per directive. +

+

Example

WasmEnv WEBAPP_SCRIPTS /my-site/scripts
+WasmEnv WEBAPP_DEBUG false
+
+ +
+
top
+

WasmMapDir Directive

+ + + + + + +
Description:Pre-open a host directory for the Wasm context.
Syntax:WasmMapDir wasm_directory host_directory
Context:server config
Status:Experimental
Module:mod_wasm
+

+ WasmMapDir is an extension of WasmDir. +

+ In this case, WasmMapDir will pre-open the host_directory, + and then mount such directory as wasm_directory within the Wasm module context. +

+ This is a security feature from the Wasm Capabilities Model, + in which no directory in the host filesystem is available in the Wasm module context unless is explicitly pre-opened. +

+ This directive can be used as many times as needed, but only one tuple wasm_directory host_directory per directive. +

+

Example

WasmMapDir /common /var/www/assets/common
+WasmMapDir /my-site /var/www/htdocs/my-site
+
+ +
+
top
+

WasmModule Directive

+ + + + + + +
Description:Define the Wasm module file name.
Syntax:WasmModule filename
Context:server config
Status:Experimental
Module:mod_wasm
+

+ WasmModule sets the Wasm file to be loaded. +

+

Example

WasmModule hello.wasm
+
+ +
+
top
+

WasmRoot Directive

+ + + + + + +
Description:Define the root directory for Wasm modules.
Syntax:WasmRoot directory
Context:server config
Status:Experimental
Module:mod_wasm
+

+ WasmRoot is the base directory where all Wasm modules should be installed. +

+

Example

WasmRoot /var/www/wasm_modules
+
+ +
+
+
+

Available Languages:  en 

+
top

Comments

Notice:
This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Libera.chat, or sent to our mailing lists.
+
+ \ No newline at end of file diff --git a/docs/manual/mod/mod_wasm.xml b/docs/manual/mod/mod_wasm.xml new file mode 100644 index 0000000000..924a7c49a2 --- /dev/null +++ b/docs/manual/mod/mod_wasm.xml @@ -0,0 +1,326 @@ + + + + + + + + + + + + + mod_wasm + Runs Wasm modules via Wasmtime engine + + Experimental + mod_wasm.c + wasm_module + Available in version 2.4.x and later + +

+ mod_wasm offers a secure enclave to run untrusted 3rd party software. + It allows WebAssembly (Wasm) modules to be executed within the Apache Server. + Code runs in a secure environment at almost native speed. + The Wasm Capabilities Model offers a secure-by-design approach to limit access to system resources. + No capabilities are enabled by default. To enable such capabilities, new directives are provided for httpd.conf. +

+ mod_wasm, being written in C, uses the library libwasm_runtime.so to interact with the Wasm engine + Wasmtime, both written in Rust. + This provides additional guarantees regarding security, memory safety, and performance. + Another module following a similar design is mod_tls. +

+ WebAssembly is a portable binary code. Therefore, developers can write programs in + their favorite programming language (C, C++, C#, Rust, Go, Swift, etc.) + and target Wasm format as the output (in the same way you can target x86_64 or aarch64). + In addition, a language runtime written in a supported language can be compiled + into Wasm (i.e.: PHP, Python, Ruby, Perl, all written in C). + And then, run their interpreters within the secure environment that mod_wasm provides. +

+ mod_wasm implements a content handler that captures the stdout from the Wasm binary, and then it is appended to the HTTP request response. +

+ + + +
+ Minimal Configuration: Running a Wasm Module +

+ Below is a minimal configuration sample of the directives needed in httpd.conf to use mod_wasm. +

+ Just set the wasm-handler to the desired route, and point to a Wasm module via WasmRoot and WasmModule. +

+ +LoadModule wasm_module modules/mod_wasm.so + +<Location /wasm-module> + SetHandler wasm-handler +</Location> + +<IfModule wasm_module> + WasmRoot /var/www/wasm_modules + WasmModule hello.wasm +</IfModule> + +
+ + +
+ Advanced Configuration: Running a Python-based WebApp +

+ Below is an advanced configuration for running a Python-based webapp within mod_wasm. +

+ The Python language runtime is in Wasm binary format. The Python script to be run is passed as an argument via WasmArg. +

+ Python runtime requires both PYTHONHOME and PYTHONPATH environment variables + to be set and point to a directory containing the Python standard library. This can be done using + WasmEnv. +

+ Also, such directories must be pre-opened and available in the Wasm context via WasmDir or WasmMapDir. +

+ Finally, CGI mode is activated using WasmEnableCGI. + This way, HTTP headers and URL parameters from the incoming request are passed to the Wasm module + as environmental variables. In this mode, it is expected that responses from the Wasm module + start with the HTTP response header (i.e.: Content-Type: text/html). +

+ +LoadModule wasm_module modules/mod_wasm.so + +<Location /wasm-module> + SetHandler wasm-handler +</Location> + +<IfModule wasm_module> + WasmRoot /var/www/wasm_modules + WasmModule python3.11.wasm + WasmMapDir /python /usr/lib/python3.11 + WasmArg /python/hello.py + WasmEnv PYTHONHOME /python/wasi-python/lib/python3.11 + WasmEnv PYTHONPATH /python/wasi-python/lib/python3.11 + WasmEnableCGI On +</IfModule> + +
+ + +
+ mod_wasm Directives Index +

+ The table below provides a comprehensive list of all directives provided by mod_wasm. +

+ + + + + + + + + +
Directive
WasmRoot
WasmModule
WasmDir
WasmMapDir
WasmArg
WasmEnv
WasmEnableCGI
+

+

+
+ + + + WasmRoot + Define the root directory for Wasm modules. + WasmRoot directory + + server config + + +

+ WasmRoot is the base directory where all Wasm modules should be installed. +

+ Example + +WasmRoot /var/www/wasm_modules + + + + + + + + WasmModule + Define the Wasm module file name. + WasmModule filename + + server config + + +

+ WasmModule sets the Wasm file to be loaded. +

+ Example + +WasmModule hello.wasm + + + + + + + + WasmDir + Pre-open a host directory for the Wasm context. + WasmDir directory + + server config + + +

+ WasmDir pre-opens a directory in the host system to be available in the Wasm context. +

+ This is a security feature from the Wasm Capabilities Model, + in which no directory in the host filesystem is available in the Wasm module context unless is explicitly pre-opened. +

+ This directive can be used as many times as needed, but only one directory per directive. +

+ Example + +WasmDir /var/www/assets/common +WasmDir /var/www/htdocs/my-site + + + + + + + + WasmMapDir + Pre-open a host directory for the Wasm context. + WasmMapDir wasm_directory host_directory + + server config + + +

+ WasmMapDir is an extension of WasmDir. +

+ In this case, WasmMapDir will pre-open the host_directory, + and then mount such directory as wasm_directory within the Wasm module context. +

+ This is a security feature from the Wasm Capabilities Model, + in which no directory in the host filesystem is available in the Wasm module context unless is explicitly pre-opened. +

+ This directive can be used as many times as needed, but only one tuple wasm_directory host_directory per directive. +

+ Example + +WasmMapDir /common /var/www/assets/common +WasmMapDir /my-site /var/www/htdocs/my-site + + + + + + + + WasmArg + Set an argument to be passed to the Wasm module context. + WasmArg argument + + server config + + +

+ WasmArg is related to the well-known argv parameter in the C int main (int argc, *argv[]) function declaration. +

+ This directive allows passing different arguments to the Wasm module as its main function + was invoked with such an argument. +

+ This directive can be used as many times as needed, but only one argument per directive. +

+ The order is accumulative, this is, the first invocation will become the first argument, and so on. +

+ Example + +WasmArg /my-site/scripts/hello.py +WasmArg --effusive-mode + + + + + + + + WasmEnv + Set an environment variable to be passed to the Wasm module context. + WasmEnv variable_name variable_value + + server config + + +

+ WasmEnv allows setting environment variables within the Wasm module context. +

+ This directive can be used as many times as needed, but only one tuple variable_name variable_value per directive. +

+ Example + +WasmEnv WEBAPP_SCRIPTS /my-site/scripts +WasmEnv WEBAPP_DEBUG false + + + + + + + + WasmEnableCGI + Enable/Disable CGI emulation mode for HTTP headers. + WasmEnableCGI On|Off + + server config + + +

+ WasmEnableCGI allows mod_wasm to connect the HTTP requests with the Wasm module in a CGI-like way: +

    +
  • HTTP headers from the request are passed to the Wasm module as environmental variables.
    • +
  • URL query parameters are passed as QUERY_STRING environmental variable.
    • +
  • Output from the Wasm module (stdout) will be parsed and headers such as Content-Type: will be + incorporated into the response headers.
    • +
+ Default value is Off. +

+ Example + +WasmEnableCGI On + + +

+ HTTP request headers are prefixed with 'HTTP_', uppercased, and hyphens '-' are substituted by underscores '_' when transformed into environmental variables. +

+ As an example, a header like x-custom-header: value will be transformed into an HTTP_X_CUSTOM_HEADER=value environmental variable. +

+ + + + + diff --git a/docs/manual/mod/mod_wasm.xml.meta b/docs/manual/mod/mod_wasm.xml.meta new file mode 100644 index 0000000000..cfa0553c88 --- /dev/null +++ b/docs/manual/mod/mod_wasm.xml.meta @@ -0,0 +1,12 @@ + + + + + mod_wasm + /mod/ + .. + + + en + + diff --git a/modules/wasm/Makefile.in b/modules/wasm/Makefile.in new file mode 100644 index 0000000000..157bd91d20 --- /dev/null +++ b/modules/wasm/Makefile.in @@ -0,0 +1,16 @@ +# Licensed to the Apache Software Foundation (ASF) under one or more +# contributor license agreements. See the NOTICE file distributed with +# this work for additional information regarding copyright ownership. +# The ASF licenses this file to You under the Apache License, Version 2.0 +# (the "License"); you may not use this file except in compliance with +# the License. You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. + +include $(top_srcdir)/build/special.mk diff --git a/modules/wasm/config.m4 b/modules/wasm/config.m4 new file mode 100644 index 0000000000..37874b20af --- /dev/null +++ b/modules/wasm/config.m4 @@ -0,0 +1,150 @@ +dnl Licensed to the Apache Software Foundation (ASF) under one or more +dnl contributor license agreements. See the NOTICE file distributed with +dnl this work for additional information regarding copyright ownership. +dnl The ASF licenses this file to You under the Apache License, Version 2.0 +dnl (the "License"); you may not use this file except in compliance with +dnl the License. You may obtain a copy of the License at +dnl +dnl http://www.apache.org/licenses/LICENSE-2.0 +dnl +dnl Unless required by applicable law or agreed to in writing, software +dnl distributed under the License is distributed on an "AS IS" BASIS, +dnl WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +dnl See the License for the specific language governing permissions and +dnl limitations under the License. + +APACHE_MODPATH_INIT(wasm) + +dnl # list of module object files +wasm_objs="dnl +mod_wasm.lo +" + +dnl +dnl APACHE_CHECK_WASMRUNTIME +dnl +dnl Configure for Wasm Runtime, giving preference to +dnl "--with-wasmruntime=" if it was specified. +dnl +AC_DEFUN([APACHE_CHECK_WASMRUNTIME],[ + AC_CACHE_CHECK([for wasmruntime], [ac_cv_wasmruntime], [ + dnl initialise the variables we use + ac_cv_wasmruntime=no + ap_wasmruntime_found="" + ap_wasmruntime_base="" + ap_wasmruntime_libs="" + + dnl Determine the Wasm Runtime base directory, if any + AC_MSG_CHECKING([for user-provided Wasm Runtime base directory]) + AC_ARG_WITH( + wasmruntime, + APACHE_HELP_STRING(--with-wasmruntime=PATH, Wasm Runtime installation directory), + [ + dnl If --with-wasmruntime specifies a directory, we use that directory + if test "x$withval" != "xyes" -a "x$withval" != "x"; then + dnl This ensures $withval is actually a directory and that it is absolute + ap_wasmruntime_base="`cd $withval ; pwd`" + fi + ]) + + if test "x$ap_wasmruntime_base" = "x"; then + AC_MSG_RESULT(none) + else + AC_MSG_RESULT() + fi + + dnl Run header and version checks + saved_CPPFLAGS="$CPPFLAGS" + saved_LIBS="$LIBS" + saved_LDFLAGS="$LDFLAGS" + + dnl Before doing anything else, load in pkg-config variables + if test -n "$PKGCONFIG"; then + saved_PKG_CONFIG_PATH="$PKG_CONFIG_PATH" + AC_MSG_CHECKING([for pkg-config along $PKG_CONFIG_PATH]) + if test "x$ap_wasmruntime_base" != "x" ; then + if test -f "${ap_wasmruntime_base}/lib/pkgconfig/libwasm_runtime.pc"; then + dnl Ensure that the given path is used by pkg-config too, otherwise + dnl the system libwasm_runtime.pc might be picked up instead. + PKG_CONFIG_PATH="${ap_wasmruntime_base}/lib/pkgconfig${PKG_CONFIG_PATH+:}${PKG_CONFIG_PATH}" + export PKG_CONFIG_PATH + elif test -f "${ap_wasmruntime_base}/lib64/pkgconfig/libwasm_runtime.pc"; then + dnl Ensure that the given path is used by pkg-config too, otherwise + dnl the system libwasm_runtime.pc might be picked up instead. + PKG_CONFIG_PATH="${ap_wasmruntime_base}/lib64/pkgconfig${PKG_CONFIG_PATH+:}${PKG_CONFIG_PATH}" + export PKG_CONFIG_PATH + fi + fi + ap_wasmruntime_libs="`$PKGCONFIG $PKGCONFIG_LIBOPTS --libs-only-l --silence-errors libwasm_runtime`" + if test $? -eq 0; then + ap_wasmruntime_found="yes" + pkglookup="`$PKGCONFIG --cflags-only-I libwasm_runtime`" + APR_ADDTO(CPPFLAGS, [$pkglookup]) + APR_ADDTO(MOD_CFLAGS, [$pkglookup]) + pkglookup="`$PKGCONFIG $PKGCONFIG_LIBOPTS --libs-only-L libwasm_runtime`" + APR_ADDTO(LDFLAGS, [$pkglookup]) + APR_ADDTO(MOD_LDFLAGS, [$pkglookup]) + pkglookup="`$PKGCONFIG $PKGCONFIG_LIBOPTS --libs-only-other libwasm_runtime`" + APR_ADDTO(LDFLAGS, [$pkglookup]) + APR_ADDTO(MOD_LDFLAGS, [$pkglookup]) + fi + PKG_CONFIG_PATH="$saved_PKG_CONFIG_PATH" + fi + + dnl fall back to the user-supplied directory if not found via pkg-config + if test "x$ap_wasmruntime_base" != "x" -a "x$ap_wasmruntime_found" = "x"; then + APR_ADDTO(CPPFLAGS, [-I$ap_wasmruntime_base/src]) + APR_ADDTO(MOD_CFLAGS, [-I$ap_wasmruntime_base/src]) + APR_ADDTO(LDFLAGS, [-L$ap_wasmruntime_base/target/release]) + APR_ADDTO(MOD_LDFLAGS, [-L$ap_wasmruntime_base/target/release]) + if test "x$ap_platform_runtime_link_flag" != "x"; then + APR_ADDTO(LDFLAGS, [$ap_platform_runtime_link_flag$ap_wasmruntime_base/target/release]) + APR_ADDTO(MOD_LDFLAGS, [$ap_platform_runtime_link_flag$ap_wasmruntime_base/target/release]) + fi + fi + + AC_MSG_CHECKING([for Wasm Runtime version >= 0.5.0]) + AC_LANG([C]) + AC_TRY_COMPILE( + [#include + #include "wasm_runtime.h"], + [wasm_runtime_init_module();], + [AC_MSG_RESULT(OK) + ac_cv_wasmruntime=yes], + [AC_MSG_RESULT(FAILED)]) + + dnl restore + CPPFLAGS="$saved_CPPFLAGS" + LIBS="$saved_LIBS" + LDFLAGS="$saved_LDFLAGS" + ]) + if test "x$ac_cv_wasmruntime" = "xyes"; then + AC_DEFINE(HAVE_WASMRUNTIME, 1, [Define if Wasm Runtime is available]) + fi +]) + + +APACHE_MODULE(wasm, [WebAssembly handler module. +This module requires a libwasm_runtime installation. +See --with-wasmruntime on how to manage non-standard locations. This module +is usually linked shared and requires loading. ], $wasm_objs, , most, [ + APACHE_CHECK_WASMRUNTIME + if test "$ac_cv_wasmruntime" = "yes" ; then + if test "x$enable_wasm" = "xshared"; then + case `uname` in + "Darwin") + MOD_WASM_LINK_LIBS="-lwasm_runtime -framework Foundation" + ;; + *) + MOD_WASM_LINK_LIBS="-lwasm_runtime" + ;; + esac + + APR_ADDTO(MOD_LDFLAGS, [$MOD_WASM_LINK_LIBS]) + fi + else + enable_wasm=no + fi +]) + +APACHE_MODPATH_FINISH diff --git a/modules/wasm/mod_wasm.c b/modules/wasm/mod_wasm.c new file mode 100644 index 0000000000..51e9a6e045 --- /dev/null +++ b/modules/wasm/mod_wasm.c @@ -0,0 +1,598 @@ +/* + * Copyright 2022 VMware, Inc. + * SPDX-License-Identifier: Apache-2.0 + */ + + +#include "httpd.h" +#include "http_config.h" +#include "http_core.h" +#include "http_log.h" +#include "http_main.h" +#include "http_protocol.h" +#include "http_request.h" +#include "util_script.h" +#include "http_connection.h" +#ifdef HAVE_UNIX_SUEXEC +#include "unixd.h" +#endif +#include "scoreboard.h" +#include "mpm_common.h" + +#include "apr_strings.h" + +#include + +#include "wasm_runtime.h" + + +/*--------------------------------------------------------------------------*/ +/* */ +/* Data declarations. */ +/* */ +/* Here are the static cells and structure declarations private to our */ +/* module. */ +/* */ +/*--------------------------------------------------------------------------*/ + +/** + * Maximum number of bytes to allocate the body from an HTTP Request. + * + * 16KB (16*1024 = 16386) + * + */ +#define CONFIG_HTTP_REQUEST_BODY_MAX 16386 + +/** + * Maximum number of arguments specified in the static configuration. + * + * If the user tries to set more arguments on the Apache + * configuration, this will raise an error. The main reason behind + * this limitation is to avoid performing reallocations. + * + * TODO: remove this limitation and reallocate as more arguments are defined. + */ +#define CONFIG_DEFINED_ARGS_MAX 32 + +/** + * Maximum number of environment variables specified in the static configuration. + * + * If the user tries to set more environment variables on the Apache + * configuration, this will raise an error. The main reason behind + * this limitation is to avoid performing reallocations. + * + * TODO: remove this limitation and reallocate as more environment + * variables are defined. + */ +#define CONFIG_DEFINED_ENVVARS_MAX 32 + +typedef struct configArg { + const char *arg; +} configArg; + +typedef struct configEnvVar { + const char *key; + const char *value; +} configEnvVar; + + +/* + * Configuration record. Used for both per-directory and per-server + * configuration data. + * + * It's perfectly reasonable to have two different structures for the two + * different environments. The same command handlers will be called for + * both, though, so the handlers need to be able to tell them apart. One + * possibility is for both structures to start with an int which is 0 for + * one and 1 for the other. + * + * Note that while the per-directory and per-server configuration records are + * available to most of the module handlers, they should be treated as + * READ-ONLY by all except the command and merge handlers. Sometimes handlers + * are handed a record that applies to the current location by implication or + * inheritance, and modifying it will change the rules for other locations. + */ +typedef struct x_cfg { + int cmode; /* Environment to which record applies + * (directory, server, or combination). + */ +#define CONFIG_MODE_SERVER 1 +#define CONFIG_MODE_DIRECTORY 2 +#define CONFIG_MODE_COMBO 3 /* Shouldn't ever happen. */ + int local; /* Boolean: "Example" directive declared + * here? + */ + int congenital; /* Boolean: did we inherit an "Example"? */ + int bEnableCGI; /* Boolean: whether this module interfaces as if it was a CGI script */ + char *trace; /* Pointer to trace string. */ + char *loc; /* Location to which this record applies. */ + + configEnvVar *configEnvVars[CONFIG_DEFINED_ENVVARS_MAX]; /* Environment variables set in the static configuration */ + int configEnvVarCount; /* Count of environment variables set in the static configuration */ + configArg *configArgs[CONFIG_DEFINED_ARGS_MAX]; /* Arguments set in the static configuration */ + int configArgCount; /* Count of arguments set in the static configuration */ +} x_cfg; + +/* + * String pointer to hold the startup trace. No harm working with a global until + * the server is (may be) multi-threaded. + */ +static const char *trace = NULL; + +/* + * Declare ourselves so the configuration routines can find and know us. + * We'll fill it in at the end of the module. + */ +module AP_MODULE_DECLARE_DATA wasm_module; + + +/*--------------------------------------------------------------------------*/ +/* */ +/* These routines are strictly internal to this module, and support its */ +/* operation. They are not referenced by any external portion of the */ +/* server. */ +/* */ +/*--------------------------------------------------------------------------*/ + +static void trace_nocontext(apr_pool_t *p, const char *file, int line, + const char *note) +{ + ap_log_perror(file, line, APLOG_MODULE_INDEX, APLOG_NOTICE, 0, p, "%s", note); +} + + +/* + * This function gets called to create a per-directory configuration + * record. This will be called for the "default" server environment, and for + * each directory for which the parser finds any of our directives applicable. + * If a directory doesn't have any of our directives involved (i.e., they + * aren't in the .htaccess file, or a , , or related + * block), this routine will *not* be called - the configuration for the + * closest ancestor is used. + * + * The return value is a pointer to the created module-specific + * structure. + */ +static void *create_dir_config(apr_pool_t *p, char *dirspec) +{ + x_cfg *cfg; + char *dname = dirspec; + char *note; + + /* + * Allocate the space for our record from the pool supplied. + */ + cfg = (x_cfg *) apr_pcalloc(p, sizeof(x_cfg)); + /* + * Now fill in the defaults. If there are any `parent' configuration + * records, they'll get merged as part of a separate callback. + */ + cfg->local = 0; + cfg->congenital = 0; + cfg->bEnableCGI = 0; + cfg->configEnvVarCount = 0; + cfg->configArgCount = 0; + cfg->cmode = CONFIG_MODE_DIRECTORY; + /* + * Finally, add our trace to the callback list. + */ + dname = (dname != NULL) ? dname : ""; + cfg->loc = apr_pstrcat(p, "DIR(", dname, ")", NULL); + note = apr_psprintf(p, "create_dir_config(p == %pp, dirspec == %s)", + (void*) p, dirspec); + return (void *) cfg; +} + +/* + * This function gets called to create a per-server configuration + * record. It will always be called for the "default" server. + * + * The return value is a pointer to the created module-specific + * structure. + */ +static void *create_server_config(apr_pool_t *p, server_rec *s) +{ + + x_cfg *cfg; + char *sname = s->server_hostname; + + /* + * As with the create_dir_config() reoutine, we allocate and fill + * in an empty record. + */ + cfg = (x_cfg *) apr_pcalloc(p, sizeof(x_cfg)); + cfg->local = 0; + cfg->congenital = 0; + cfg->bEnableCGI = 0; + cfg->cmode = CONFIG_MODE_SERVER; + /* + * Note that we were called in the trace list. + */ + sname = (sname != NULL) ? sname : ""; + cfg->loc = apr_pstrcat(p, "SVR(", sname, ")", NULL); + trace_nocontext(NULL, __FILE__, __LINE__, sname); + return (void *) cfg; +} + +/* + * Post-config hook + */ +static int post_config_hook(apr_pool_t *pconf, apr_pool_t *plog, + apr_pool_t *ptemp, server_rec *s) +{ + trace_nocontext(NULL, __FILE__, __LINE__, "post_config_hook() - initializing wasm_runtime..."); + + // init wasm_runtime + const char* result = wasm_runtime_init_module(); + + if (strcmp(result, "") != 0) // something went wrong + trace_nocontext(NULL, __FILE__, __LINE__, "post_config_hook() - ERROR! Couldn't initiale wasm_runtime!"); + else + trace_nocontext(NULL, __FILE__, __LINE__, "post_config_hook() - wasm_runtime initialized!"); + + return_const_char_ownership(result); + + return OK; +} + +// Add the provided key to the wasmtime runtime as an environment +// variable. +static int _wasm_config_add_env(void *h_, const char *key, const char *value) +{ + wasm_config_add_env(key, value); + return 1; +} + +// Populates the runtime with the arguments defined in the static +// configuration. +static void populate_runtime_with_config_defined_args(x_cfg *cfg) +{ + for (int i = 0; i < cfg->configArgCount; ++i) { + wasm_config_add_arg(cfg->configArgs[i]->arg); + } +} + +// Populates the runtime with the environment variables defined in the +// static configuration. +static void populate_runtime_with_config_defined_envs(x_cfg *cfg) +{ + for (int i = 0; i < cfg->configEnvVarCount; ++i) { + configEnvVar *envVar = cfg->configEnvVars[i]; + wasm_config_add_env(envVar->key, envVar->value); + } +} + + + +/* + * This function reads the HTTP Request Body + * + * r: request + * rbuff: buffer to where the body will be allocated + * size: size of the buffer allocated + * + * More info: + * - https://httpd.apache.org/docs/trunk/developer/modguide.html (section: "Reading the request body into memory") + * - https://docstore.mik.ua/orelly/apache_mod/139.htm + */ +static int read_http_request_body(request_rec *r, const char **rbuf, apr_off_t *size) +{ + int rc = DECLINED; // return code ('DECLINED' by default) + + // setup the client to allow Apache to read the request body + if ( (rc = ap_setup_client_block(r, REQUEST_CHUNKED_ERROR)) != OK ) + { + return rc; + } + + + // can we read or abort? + if ( ap_should_client_block(r) ) + { + char argsbuffer[CONFIG_HTTP_REQUEST_BODY_MAX]; + apr_off_t rsize, len_read, rpos = 0; + apr_off_t length = r->remaining; + + *rbuf = (const char *) apr_pcalloc( r->pool, (apr_size_t)(length + 1) ); + *size = length; + while ( (len_read = ap_get_client_block(r, argsbuffer, sizeof(argsbuffer))) > 0 ) + { + if ( (rpos + len_read) > length ) + { + rsize = length - rpos; + } + else + { + rsize = len_read; + } + + memcpy( (char *)*rbuf + rpos, argsbuffer, (size_t)rsize ); + rpos += rsize; + } + } + + return rc; +} + + +/* + * Content handler + */ +static int content_handler(request_rec *r) +{ + /* If it's not for us, get out as soon as possible. */ + if (strcmp(r->handler, "wasm-handler")) { + return DECLINED; + } + + /* + * If we're only supposed to send header information (HEAD request), we're + * already there. + */ + if (r->header_only) { + return OK; + } + + x_cfg *dcfg = ap_get_module_config(r->per_dir_config, &wasm_module); + + // Reset initial state: to be revised with multiple + // workers/threads. + // + // This reset to initial state is crucial when the module is + // behaving as a CGI module, because arguments and environnent + // variables might be set depending on the data of the + // request. However, the user might have also added some static + // arguments and environment variables to the Apache + // configuration. + wasm_config_clear_args(); + wasm_config_clear_envs(); + populate_runtime_with_config_defined_args(dcfg); + populate_runtime_with_config_defined_envs(dcfg); + + if (dcfg->bEnableCGI) { + // On CGI mode, we set the request headers as environment + // variables with an HTTP_ prefix. + ap_add_common_vars(r); + ap_add_cgi_vars(r); + apr_table_do(_wasm_config_add_env, NULL, r->subprocess_env, NULL); + + // read request body and store it as WASI Stdin + apr_off_t body_size = 0; + const char* body_buffer; + + if ( read_http_request_body(r, &body_buffer, &body_size) != OK ) { + trace_nocontext(NULL, __FILE__, __LINE__, "content_handler() - ERROR! Couldn't read HTTP Request Body!"); + } + else + { + wasm_config_set_stdin(body_buffer, body_size); + } + } + + + // run Wasm module + const char* module_response = wasm_runtime_run_module(); + if (dcfg->bEnableCGI) { + // Retrieve the CGI variables and feed our own response with + // them; write the response from the module as our own response; + // which has the headers already stripped from it. + const char *termch; + int termarg; + int ret = ap_scan_script_header_err_strs(r, NULL, &termch, &termarg, module_response, NULL); + // ap_scan_script_header_err_strs can return either: + // - HTTP_OK: success + // - HTTP_INTERNAL_SERVER_ERROR: failure + // - HTTP_NOT_MODIFIED or HTTP_PRECONDITION_FAILED: script + // response does not meet request's conditions + // In order to not give the external consumer more information + // than what is needed, map all responses to a 500 error. + if (ret != 0 && ret != HTTP_OK) { + return_const_char_ownership(module_response); + return HTTP_INTERNAL_SERVER_ERROR; + } + if (termch != NULL) { + ap_rprintf(r, "%s", termch); + } + } else if (module_response != NULL) { + ap_rprintf(r, "%s", module_response); + } + return_const_char_ownership(module_response); + + return OK; +} + + +/*--------------------------------------------------------------------------*/ +/* */ +/* Which functions are responsible for which hooks in the server. */ +/* */ +/*--------------------------------------------------------------------------*/ +/* + * Each function our module provides to handle a particular hook is + * specified here. The functions are registered using + * ap_hook_foo(name, predecessors, successors, position) + * where foo is the name of the hook. + * + * The args are as follows: + * name -> the name of the function to call. + * predecessors -> a list of modules whose calls to this hook must be + * invoked before this module. + * successors -> a list of modules whose calls to this hook must be + * invoked after this module. + * position -> The relative position of this module. One of + * APR_HOOK_FIRST, APR_HOOK_MIDDLE, or APR_HOOK_LAST. + * Most modules will use APR_HOOK_MIDDLE. If multiple + * modules use the same relative position, Apache will + * determine which to call first. + * If your module relies on another module to run first, + * or another module running after yours, use the + * predecessors and/or successors. + * + * The number in brackets indicates the order in which the routine is called + * during request processing. Note that not all routines are necessarily + * called (such as if a resource doesn't have access restrictions). + * The actual delivery of content to the browser [9] is not handled by + * a hook; see the handler declarations below. + */ +static void register_hooks(apr_pool_t *p) +{ + ap_hook_post_config(post_config_hook, NULL, NULL, APR_HOOK_MIDDLE); + ap_hook_handler(content_handler, NULL, NULL, APR_HOOK_MIDDLE); +} + + +#define WASM_DIRECTIVE_WASMROOT "WasmRoot" +#define WASM_DIRECTIVE_WASMMODULE "WasmModule" +#define WASM_DIRECTIVE_WASMARG "WasmArg" +#define WASM_DIRECTIVE_WASMENV "WasmEnv" +#define WASM_DIRECTIVE_WASMDIR "WasmDir" +#define WASM_DIRECTIVE_WASMMAPDIR "WasmMapDir" +#define WASM_DIRECTIVE_ENABLECGI "WasmEnableCGI" + + +static const char *wasm_directive_WasmRoot(cmd_parms *cmd, void *mconfig, const char *word1) +{ + x_cfg *cfg = (x_cfg *) mconfig; + wasm_config_set_root(word1); + return NULL; +} + + +static const char *wasm_directive_WasmModule(cmd_parms *cmd, void *mconfig, const char *word1) +{ + x_cfg *cfg = (x_cfg *) mconfig; + wasm_config_set_module(word1); + return NULL; +} + + +static const char *wasm_directive_WasmArg(cmd_parms *cmd, void *mconfig, const char *word1) +{ + x_cfg *cfg = (x_cfg *) mconfig; + if (cfg->configArgCount == CONFIG_DEFINED_ARGS_MAX) { + return apr_psprintf(cmd->pool, "WasmArg limit reached in the httpd configuration (maximum is %d)", CONFIG_DEFINED_ARGS_MAX); + } + configArg *arg = malloc(sizeof(configArg)); + arg->arg = apr_pstrdup(cmd->pool, word1); + cfg->configArgs[cfg->configArgCount] = arg; + cfg->configArgCount++; + return NULL; +} + + +static const char *wasm_directive_WasmEnv(cmd_parms *cmd, void *mconfig, const char *word1, const char *word2) +{ + x_cfg *cfg = (x_cfg *) mconfig; + if (cfg->configEnvVarCount == CONFIG_DEFINED_ENVVARS_MAX) { + return apr_psprintf(cmd->pool, "WasmEnv limit reached in the httpd configuration (maximum is %d)", CONFIG_DEFINED_ENVVARS_MAX); + } + configEnvVar *env = malloc(sizeof(configEnvVar)); + env->key = apr_pstrdup(cmd->pool, word1); + env->value = apr_pstrdup(cmd->pool, word2); + cfg->configEnvVars[cfg->configEnvVarCount] = env; + cfg->configEnvVarCount++; + return NULL; +} + + +static const char *wasm_directive_WasmDir(cmd_parms *cmd, void *mconfig, const char *word1) +{ + x_cfg *cfg = (x_cfg *) mconfig; + wasm_config_add_dir(word1); + return NULL; +} + + +static const char *wasm_directive_WasmMapDir(cmd_parms *cmd, void *mconfig, const char *word1, const char *word2) +{ + x_cfg *cfg = (x_cfg *) mconfig; + wasm_config_add_mapdir(word1, word2); + return NULL; +} + +static const char *wasm_directive_WasmEnableCGI(cmd_parms *cmd, void *mconfig, int arg) +{ + x_cfg *cfg = (x_cfg *) mconfig; + cfg->bEnableCGI = arg; + return NULL; +} + +/* + * List of directives specific to our module. + */ +static const command_rec directives[] = +{ + AP_INIT_TAKE1( + WASM_DIRECTIVE_WASMROOT, /* directive name */ + wasm_directive_WasmRoot, /* config action routine */ + NULL, /* argument to include in call */ + OR_OPTIONS, /* where available */ + "Set root directory for the Wasm file" /* directive description */ + ), + AP_INIT_TAKE1( + WASM_DIRECTIVE_WASMMODULE, + wasm_directive_WasmModule, + NULL, + OR_OPTIONS, + "Set filename for the Wasm Module" + ), + AP_INIT_TAKE1( + WASM_DIRECTIVE_WASMARG, + wasm_directive_WasmArg, + NULL, + OR_OPTIONS, + "Add arg context for the Wasm Module" + ), + AP_INIT_TAKE2( + WASM_DIRECTIVE_WASMENV, + wasm_directive_WasmEnv, + NULL, + OR_OPTIONS, + "Set environtment variable for the Wasm Module" + ), + AP_INIT_TAKE1( + WASM_DIRECTIVE_WASMDIR, + wasm_directive_WasmDir, + NULL, + OR_OPTIONS, + "Preopen Dir for the Wasm Module" + ), + AP_INIT_TAKE2( + WASM_DIRECTIVE_WASMMAPDIR, + wasm_directive_WasmMapDir, + NULL, + OR_OPTIONS, + "Preopen Dir with Mapping for the Wasm Module" + ), + AP_INIT_FLAG( + WASM_DIRECTIVE_ENABLECGI, + wasm_directive_WasmEnableCGI, + NULL, + OR_OPTIONS, + "Whether this WebAssembly module behaves as a CGI" + ), + {NULL} +}; + + + +/*--------------------------------------------------------------------------*/ +/* */ +/* Finally, the list of callback routines and data structures that provide */ +/* the static hooks into our module from the other parts of the server. */ +/* */ +/*--------------------------------------------------------------------------*/ +/* + * Module definition for configuration. If a particular callback is not + * needed, replace its routine name below with the word NULL. + */ +AP_DECLARE_MODULE(wasm) = +{ + STANDARD20_MODULE_STUFF, + create_dir_config, /* per-directory config creator */ + NULL, /* dir config merger */ + create_server_config, /* server config creator */ + NULL, /* server config merger */ + directives, /* command table */ + register_hooks, /* set up other request processing hooks */ +}; -- 2.37.0