Changes

CMakeLists.txt

@@ -4,23 +4,11 @@ cmake_minimum_required(VERSION 3.17.0)
 project(runtime)
 
 # Headers
-add_library(trampoline-headers INTERFACE)
+add_subdirectory(lib)
-target_include_directories(trampoline-headers INTERFACE include)
+if(TARGET trampoline)
-
-# Check Architecture
-include(CheckSymbolExists)
-check_symbol_exists("__arm__" "" NO_RUNTIME_NEEDED)
-if(NO_RUNTIME_NEEDED)
     return()
 endif()
 
-# Only Headers
-option(TRAMPOLINE_HEADERS_ONLY "Skip Building Runtime" FALSE)
-if(TRAMPOLINE_HEADERS_ONLY)
-    return()
-endif()
-target_compile_definitions(trampoline-headers INTERFACE MCPI_BUILD_RUNTIME)
-
 # Build
 add_executable(runtime
     src/main.cpp
@@ -45,9 +33,15 @@ endif()
 target_compile_options(runtime PRIVATE -Wall -Wextra -Werror -Wpointer-arith -Wshadow -Wnull-dereference)
 
 # Link
-target_link_libraries(runtime dl rt trampoline-headers)
+target_link_libraries(runtime
+    dl
+    rt
+    trampoline-headers
+)
 
 # Install
 if(DEFINED MCPI_BIN_DIR)
     install(TARGETS runtime DESTINATION "${MCPI_BIN_DIR}")
+    # License
+    install(FILES "${CMAKE_CURRENT_SOURCE_DIR}/LICENSE" DESTINATION "${MCPI_LEGAL_DIR}/${PROJECT_NAME}")
 endif()

LICENSE

@@ -0,0 +1,339 @@
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+                            Preamble
+
+  The licenses for most software are designed to take away your
+freedom to share and change it.  By contrast, the GNU General Public
+License is intended to guarantee your freedom to share and change free
+software--to make sure the software is free for all its users.  This
+General Public License applies to most of the Free Software
+Foundation's software and to any other program whose authors commit to
+using it.  (Some other Free Software Foundation software is covered by
+the GNU Lesser General Public License instead.)  You can apply it to
+your programs, too.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+this service if you wish), that you receive source code or can get it
+if you want it, that you can change the software or use pieces of it
+in new free programs; and that you know you can do these things.
+
+  To protect your rights, we need to make restrictions that forbid
+anyone to deny you these rights or to ask you to surrender the rights.
+These restrictions translate to certain responsibilities for you if you
+distribute copies of the software, or if you modify it.
+
+  For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must give the recipients all the rights that
+you have.  You must make sure that they, too, receive or can get the
+source code.  And you must show them these terms so they know their
+rights.
+
+  We protect your rights with two steps: (1) copyright the software, and
+(2) offer you this license which gives you legal permission to copy,
+distribute and/or modify the software.
+
+  Also, for each author's protection and ours, we want to make certain
+that everyone understands that there is no warranty for this free
+software.  If the software is modified by someone else and passed on, we
+want its recipients to know that what they have is not the original, so
+that any problems introduced by others will not reflect on the original
+authors' reputations.
+
+  Finally, any free program is threatened constantly by software
+patents.  We wish to avoid the danger that redistributors of a free
+program will individually obtain patent licenses, in effect making the
+program proprietary.  To prevent this, we have made it clear that any
+patent must be licensed for everyone's free use or not licensed at all.
+
+  The precise terms and conditions for copying, distribution and
+modification follow.
+
+                    GNU GENERAL PUBLIC LICENSE
+   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
+
+  0. This License applies to any program or other work which contains
+a notice placed by the copyright holder saying it may be distributed
+under the terms of this General Public License.  The "Program", below,
+refers to any such program or work, and a "work based on the Program"
+means either the Program or any derivative work under copyright law:
+that is to say, a work containing the Program or a portion of it,
+either verbatim or with modifications and/or translated into another
+language.  (Hereinafter, translation is included without limitation in
+the term "modification".)  Each licensee is addressed as "you".
+
+Activities other than copying, distribution and modification are not
+covered by this License; they are outside its scope.  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 (independent of having been made by running the Program).
+Whether that is true depends on what the Program does.
+
+  1. You may copy and distribute verbatim copies of the Program's
+source code as you receive it, in any medium, provided that you
+conspicuously and appropriately publish on each copy an appropriate
+copyright notice and disclaimer of warranty; 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.
+
+You may charge a fee for the physical act of transferring a copy, and
+you may at your option offer warranty protection in exchange for a fee.
+
+  2. You may modify your copy or copies of the Program or any portion
+of it, thus forming a work based on the Program, and copy and
+distribute such modifications or work under the terms of Section 1
+above, provided that you also meet all of these conditions:
+
+    a) You must cause the modified files to carry prominent notices
+    stating that you changed the files and the date of any change.
+
+    b) 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.
+
+    c) If the modified program normally reads commands interactively
+    when run, you must cause it, when started running for such
+    interactive use in the most ordinary way, to print or display an
+    announcement including an appropriate copyright notice and a
+    notice that there is no warranty (or else, saying that you provide
+    a warranty) and that users may redistribute the program under
+    these conditions, and telling the user how to view a copy of this
+    License.  (Exception: if the Program itself is interactive but
+    does not normally print such an announcement, your work based on
+    the Program is not required to print an announcement.)
+
+These requirements apply to the modified work as a whole.  If
+identifiable sections of that work are not derived from the Program,
+and can be reasonably considered independent and separate works in
+themselves, then this License, and its terms, do not apply to those
+sections when you distribute them as separate works.  But when you
+distribute the same sections as part of a whole which is a work based
+on the Program, the distribution of the whole must be on the terms of
+this License, whose permissions for other licensees extend to the
+entire whole, and thus to each and every part regardless of who wrote it.
+
+Thus, it is not the intent of this section to claim rights or contest
+your rights to work written entirely by you; rather, the intent is to
+exercise the right to control the distribution of derivative or
+collective works based on the Program.
+
+In addition, mere aggregation of another work not based on the Program
+with the Program (or with a work based on the Program) on a volume of
+a storage or distribution medium does not bring the other work under
+the scope of this License.
+
+  3. You may copy and distribute the Program (or a work based on it,
+under Section 2) in object code or executable form under the terms of
+Sections 1 and 2 above provided that you also do one of the following:
+
+    a) Accompany it with the complete corresponding machine-readable
+    source code, which must be distributed under the terms of Sections
+    1 and 2 above on a medium customarily used for software interchange; or,
+
+    b) Accompany it with a written offer, valid for at least three
+    years, to give any third party, for a charge no more than your
+    cost of physically performing source distribution, a complete
+    machine-readable copy of the corresponding source code, to be
+    distributed under the terms of Sections 1 and 2 above on a medium
+    customarily used for software interchange; or,
+
+    c) Accompany it with the information you received as to the offer
+    to distribute corresponding source code.  (This alternative is
+    allowed only for noncommercial distribution and only if you
+    received the program in object code or executable form with such
+    an offer, in accord with Subsection b above.)
+
+The source code for a work means the preferred form of the work for
+making modifications to it.  For an executable work, complete source
+code means all the source code for all modules it contains, plus any
+associated interface definition files, plus the scripts used to
+control compilation and installation of the executable.  However, as a
+special exception, the source code distributed need not include
+anything that is normally distributed (in either source or binary
+form) with the major components (compiler, kernel, and so on) of the
+operating system on which the executable runs, unless that component
+itself accompanies the executable.
+
+If distribution of executable or object code is made by offering
+access to copy from a designated place, then offering equivalent
+access to copy the source code from the same place counts as
+distribution of the source code, even though third parties are not
+compelled to copy the source along with the object code.
+
+  4. You may not copy, modify, sublicense, or distribute the Program
+except as expressly provided under this License.  Any attempt
+otherwise to copy, modify, sublicense or distribute the Program is
+void, and will automatically terminate your rights under this License.
+However, parties who have received copies, or rights, from you under
+this License will not have their licenses terminated so long as such
+parties remain in full compliance.
+
+  5. You are not required to accept this License, since you have not
+signed it.  However, nothing else grants you permission to modify or
+distribute the Program or its derivative works.  These actions are
+prohibited by law if you do not accept this License.  Therefore, by
+modifying or distributing the Program (or any work based on the
+Program), you indicate your acceptance of this License to do so, and
+all its terms and conditions for copying, distributing or modifying
+the Program or works based on it.
+
+  6. Each time you redistribute the Program (or any work based on the
+Program), the recipient automatically receives a license from the
+original licensor to copy, distribute or modify the Program subject to
+these terms and conditions.  You may not impose any further
+restrictions on the recipients' exercise of the rights granted herein.
+You are not responsible for enforcing compliance by third parties to
+this License.
+
+  7. If, as a consequence of a court judgment or allegation of patent
+infringement or for any other reason (not limited to patent issues),
+conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License.  If you cannot
+distribute so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you
+may not distribute the Program at all.  For example, if a patent
+license would not permit royalty-free redistribution of the Program by
+all those who receive copies directly or indirectly through you, then
+the only way you could satisfy both it and this License would be to
+refrain entirely from distribution of the Program.
+
+If any portion of this section is held invalid or unenforceable under
+any particular circumstance, the balance of the section is intended to
+apply and the section as a whole is intended to apply in other
+circumstances.
+
+It is not the purpose of this section to induce you to infringe any
+patents or other property right claims or to contest validity of any
+such claims; this section has the sole purpose of protecting the
+integrity of the free software distribution system, which is
+implemented by public license practices.  Many people have made
+generous contributions to the wide range of software distributed
+through that system in reliance on consistent application of that
+system; it is up to the author/donor to decide if he or she is willing
+to distribute software through any other system and a licensee cannot
+impose that choice.
+
+This section is intended to make thoroughly clear what is believed to
+be a consequence of the rest of this License.
+
+  8. If the distribution and/or use of the Program is restricted in
+certain countries either by patents or by copyrighted interfaces, the
+original copyright holder who places the Program under this License
+may add an explicit geographical distribution limitation excluding
+those countries, so that distribution is permitted only in or among
+countries not thus excluded.  In such case, this License incorporates
+the limitation as if written in the body of this License.
+
+  9. The Free Software Foundation may publish revised and/or new versions
+of the General Public License from time to time.  Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+Each version is given a distinguishing version number.  If the Program
+specifies a version number of this License which applies to it and "any
+later version", you have the option of following the terms and conditions
+either of that version or of any later version published by the Free
+Software Foundation.  If the Program does not specify a version number of
+this License, you may choose any version ever published by the Free Software
+Foundation.
+
+  10. If you wish to incorporate parts of the Program into other free
+programs whose distribution conditions are different, write to the author
+to ask for permission.  For software which is copyrighted by the Free
+Software Foundation, write to the Free Software Foundation; we sometimes
+make exceptions for this.  Our decision will be guided by the two goals
+of preserving the free status of all derivatives of our free software and
+of promoting the sharing and reuse of software generally.
+
+                            NO WARRANTY
+
+  11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
+FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
+OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
+PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
+OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
+TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
+PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
+REPAIR OR CORRECTION.
+
+  12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
+REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
+INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
+OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
+TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
+YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
+PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGES.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+convey the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+Also add information on how to contact you by electronic and paper mail.
+
+If the program is interactive, make it output a short notice like this
+when it starts in an interactive mode:
+
+    Gnomovision version 69, Copyright (C) year name of author
+    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, the commands you use may
+be called something other than `show w' and `show c'; they could even be
+mouse-clicks or menu items--whatever suits your program.
+
+You should also get your employer (if you work as a programmer) or your
+school, if any, to sign a "copyright disclaimer" for the program, if
+necessary.  Here is a sample; alter the names:
+
+  Yoyodyne, Inc., hereby disclaims all copyright interest in the program
+  `Gnomovision' (which makes passes at compilers) written by James Hacker.
+
+  <signature of Ty Coon>, 1 April 1989
+  Ty Coon, President of Vice
+
+This General Public License does not permit incorporating your program into
+proprietary programs.  If your program is a subroutine library, you may
+consider it more useful to permit linking proprietary applications with the
+library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.

README.md

@@ -1,25 +1,29 @@
-# MCPI-Reborn Runtime
+# Reborn Runtime
-**Fact:** Minecraft: Pi Edition is a 32-bit ARM program.
+This is a simple program allowing ARM32 code to easily call "native" code.
 
-**Another fact:** Most modern computers do not use 32-bit ARM and therefore cannot run MCPI natively.
+By running an ARM32 program inside this runtime, it gains the ability to call `raw_trampoline`. This function copies its arguments and passes them to the `trampoline` function inside `libmedia-layer-trampoline.so`.
 
-**Solution:** This project allows MCPI to run on modern computers.
+The runtime also automatically uses QEMU on x86_64 systems.
 
-## How
+## Terminology
-This project works differently depending on the host system's architecture.
+- "Guest" code is the main ARM32 program.
+- "Host" code is the native code located in `libmedia-layer-trampoline.so`.
 
-### 64-Bit x86 Host
+## Example
-On this platform, a patched version of QEMU is used.
+There is a simple C example [here](./example). It sends a given string to the host, which returns the string's length multiplied by two.
 
-QEMU emulates ARM code so MCPI can run on x86 hardware. And the patch adds a system-call which allows MCPI to run graphics code on the host. This prevents the need for emulated GPU drivers.
+## Early Returning
+`raw_trampoline` supports returning before the host code has finished executing. This can be enabled by passing `true` to `allow_early_return`. However, this is only supported in certain circumstances, can cause race-conditions, and prevents the guest code from receiving the host's return value.
 
-### 64-Bit ARM Host
+## Syscall Versus Pipe Trampolines
-QEMU is not necessary on this platform because it can already run 32-bit ARM code natively.
+The runtime supports two methods of passing data between the guest and host.
+- System Call
+  - Data is passed through a custom system-call added to QEMU.
+  - Only supported on x86_64.
+- Pipes
+  - Data is passed through standard UNIX pipes.
+  - Supports early-returning.
+  - Can be forced using an environmental variable.
 
-Instead, the runtime is implemented as two processes: a parent and a child. The child becomes MCPI and can send graphics commands to the parent. And because the parent is 64-bit, 32-bit drivers are not needed.
+## Licensing
-
+The runtime itself is licensed with [GPLv2](./LICENSE) to comply with QEMU's license. However, the `raw_trampoline` function and associated headers are licensed with the [Unlicense](lib/LICENSE) as they do not directly link to the runtime.
-### 32-Bit ARM Host
-This project is unnecessary on this platform.
-
-### Other Architectures
-Any unlisted platforms are unsupported.

example/.gitignore

@@ -0,0 +1,2 @@
+/build
+/run.sh

example/build.sh

@@ -0,0 +1,51 @@
+#!/bin/sh
+
+set -e
+
+# Run Script
+RUN="$(pwd)/run.sh"
+rm -f "${RUN}"
+out() {
+    echo "$1" >> "${RUN}"
+}
+out '#!/bin/sh'
+out 'set -e'
+chmod +x "${RUN}"
+
+# Create Build Directory
+rm -rf build
+dir() {
+    mkdir "$1"
+    cd "$1"
+}
+dir build
+
+# Build Runtime
+dir runtime
+build() {
+    cmake -GNinja "../../$1"
+    cmake --build .
+}
+build ../
+out "export PATH=\"$(pwd):\${PATH}\""
+cd ../
+
+# Build Host Component
+build_example_part() {
+    dir "$1"
+    build "$1"
+}
+build_example_part host
+out "export LD_LIBRARY_PATH=\"$(pwd):\${LD_LIBRARY_PATH}\""
+cd ../
+
+# Build Guest Component
+build_example_part guest
+
+# Finalize Script
+out "export QEMU_LD_PREFIX=/usr/arm-linux-gnueabihf"
+out "exec runtime \"$(pwd)/example\""
+
+# Done
+echo 'BUILD COMPLETE!'
+echo 'See ./run.sh'

example/guest/CMakeLists.txt

@@ -0,0 +1,17 @@
+cmake_minimum_required(VERSION 3.17.0)
+
+# Build For ARM
+set(CMAKE_C_COMPILER arm-linux-gnueabihf-gcc)
+set(CMAKE_CXX_COMPILER arm-linux-gnueabihf-g++)
+set(CMAKE_SYSTEM_NAME "Linux")
+set(CMAKE_SYSTEM_PROCESSOR "arm")
+
+# Start Project
+project(guest)
+
+# Build Library
+add_subdirectory(../../lib lib)
+
+# Build
+add_executable(example src/example.c)
+target_link_libraries(example trampoline)

example/guest/src/example.c

@@ -0,0 +1,19 @@
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <trampoline/types.h>
+
+void run(uint32_t cmd, const char *str) {
+    // Arguments Must Be Modifiable
+    unsigned char *args = (unsigned char *) strdup(str);
+    // Sned Command
+    fprintf(stderr, "Guest Is Sending: %u: %s\n", cmd, str);
+    uint32_t ret = raw_trampoline(cmd, 0, strlen(str) + 1, args);
+    fprintf(stderr, "Guest Has Received: %u\n", ret);
+    free(args);
+}
+int main() {
+    run(0, "Hello World!");
+    run(1, "Bye World!");
+}

example/host/CMakeLists.txt

@@ -0,0 +1,11 @@
+cmake_minimum_required(VERSION 3.17.0)
+
+# Start Project
+project(host)
+
+# Build Library
+add_subdirectory(../../lib lib)
+
+# Build
+add_library(media-layer-trampoline SHARED src/trampoline.c)
+target_link_libraries(media-layer-trampoline trampoline-headers)

example/host/src/trampoline.c

@@ -0,0 +1,14 @@
+#include <string.h>
+#include <stdio.h>
+
+#include <trampoline/types.h>
+
+// writer: Function That Can Write To Guest Memory
+// id: Command ID
+// args: Pointer To Command Arguments
+// Return Value: Returned To The Guest (Unless Early Return Is Enabled)
+uint32_t trampoline(trampoline_writer_t writer, uint32_t id, const unsigned char *args) {
+    const char *str = (const char *) args;
+    fprintf(stderr, "Host Has Recieved: %u: %s\n", id, str);
+    return strlen(str) * 2;
+}

lib/CMakeLists.txt

@@ -0,0 +1,20 @@
+cmake_minimum_required(VERSION 3.17.0)
+
+# Start Project
+project(trampoline)
+
+# Headers
+add_library(trampoline-headers INTERFACE)
+target_include_directories(trampoline-headers INTERFACE include)
+
+# Check Architecture
+include(CheckSymbolExists)
+check_symbol_exists("__arm__" "" TRAMPOLINE_IS_GUEST)
+if(NOT TRAMPOLINE_IS_GUEST)
+    target_compile_definitions(trampoline-headers INTERFACE MCPI_BUILD_RUNTIME)
+    return()
+endif()
+
+# Library To Call Trampoline
+add_library(trampoline OBJECT src/guest.cpp)
+target_link_libraries(trampoline trampoline-headers)

lib/LICENSE

@@ -0,0 +1,24 @@
+This is free and unencumbered software released into the public domain.
+
+Anyone is free to copy, modify, publish, use, compile, sell, or
+distribute this software, either in source code form or as a compiled
+binary, for any purpose, commercial or non-commercial, and by any
+means.
+
+In jurisdictions that recognize copyright laws, the author or authors
+of this software dedicate any and all copyright interest in the
+software to the public domain. We make this dedication for the benefit
+of the public at large and to the detriment of our heirs and
+successors. We intend this dedication to be an overt act of
+relinquishment in perpetuity of all present and future rights to this
+software under copyright law.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
+
+For more information, please refer to <https://unlicense.org>

lib/include/trampoline/types.h

@@ -2,6 +2,11 @@
 
 #include <stdint.h>
 
+// C++ Support
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 // Maximum Arguments Length
 #define MAX_TRAMPOLINE_ARGS_SIZE 33554432 // 32 MiB
 
@@ -17,10 +22,26 @@ struct trampoline_pipe_arguments {
 };
 
 // Function Types
+#ifdef MCPI_BUILD_RUNTIME
 typedef void (*trampoline_writer_t)(uint32_t guest_addr, const void *data, uint32_t size);
-typedef uint32_t (*trampoline_t)(trampoline_writer_t writer, uint32_t id, const unsigned char *args);
+typedef uint32_t trampoline_raw_t(trampoline_writer_t writer, uint32_t id, const unsigned char *args);
+trampoline_raw_t trampoline;
+typedef trampoline_raw_t *trampoline_t;
+#endif
 
 // Environmental Variables
+#ifdef __cplusplus
 #define ENV(name, ...) constexpr const char *name##_ENV = #name;
 #include "env-list.h"
 #undef ENV
+#endif
+
+// Call Trampoline From Guest Code
+#ifndef MCPI_BUILD_RUNTIME
+uint32_t raw_trampoline(uint32_t id, int allow_early_return, uint32_t length, unsigned char *args);
+#endif
+
+// C++
+#ifdef __cplusplus
+}
+#endif

lib/src/guest.cpp

@@ -0,0 +1,86 @@
+#include <unistd.h>
+#include <string>
+#include <cstring>
+
+#include <trampoline/types.h>
+
+// Logging
+#define ERR(format, ...) \
+    ({ \
+        fprintf(stderr, "TRAMPOLINE ERROR: " format "\n", ##__VA_ARGS__); \
+        exit(EXIT_FAILURE); \
+    })
+
+// Syscall Method
+static uint32_t trampoline_syscall(const uint32_t id, unsigned char *args) {
+    // Make Syscall
+    const long ret = syscall(TRAMPOLINE_SYSCALL, id, args); // This Modifies Arguments
+    if (ret == -1) {
+        // Error
+        ERR("System Call Error: %s", strerror(errno));
+    }
+    // Return
+    return *(uint32_t *) args;
+}
+
+// Pipe Method
+static int get_pipe(const char *env) {
+    const char *value = getenv(env);
+    if (value == nullptr) {
+        ERR("Missing Variable: %s", env);
+    }
+    const std::string str = value;
+    return std::stoi(str);
+}
+static uint32_t trampoline_pipe(const uint32_t id, const bool allow_early_return, const uint32_t length, const unsigned char *args) {
+    // Get Pipes
+    static int arguments_pipe = -1;
+    static int return_value_pipe = -1;
+    if (arguments_pipe == -1) {
+        arguments_pipe = get_pipe(_MCPI_TRAMPOLINE_ARGUMENTS_ENV);
+        return_value_pipe = get_pipe(_MCPI_TRAMPOLINE_RETURN_VALUE_ENV);
+    }
+    // Write Command
+    const trampoline_pipe_arguments cmd = {
+        .id = id,
+        .allow_early_return = allow_early_return,
+        .length = length
+    };
+    if (write(arguments_pipe, &cmd, sizeof(trampoline_pipe_arguments)) != sizeof(trampoline_pipe_arguments)) {
+        ERR("Unable To Write Command");
+    }
+    // Write Arguments
+    size_t position = 0;
+    while (position < length) {
+        const ssize_t ret = write(arguments_pipe, args + position, length - position);
+        if (ret == -1) {
+            ERR("Unable To Write Arguments");
+        } else {
+            position += ret;
+        }
+    }
+    if (allow_early_return) {
+        return 0;
+    }
+    // Return
+    uint32_t ret;
+    if (read(return_value_pipe, &ret, sizeof(uint32_t)) != sizeof(uint32_t)) {
+        ERR("Unable To Read Return Value");
+    }
+    return ret;
+}
+
+// Main Function
+uint32_t raw_trampoline(const uint32_t id, const int allow_early_return, const uint32_t length, unsigned char *args) {
+    if (length > MAX_TRAMPOLINE_ARGS_SIZE) {
+        ERR("Command Too Big");
+    }
+    // Configure Method
+    static bool use_syscall = getenv(MCPI_USE_PIPE_TRAMPOLINE_ENV) == nullptr;
+    // Use Correct Method
+    if (use_syscall) {
+        return trampoline_syscall(id, args);
+    } else {
+        return trampoline_pipe(id, allow_early_return, length, args);
+    }
+}

qemu/CMakeLists.txt

@@ -6,46 +6,53 @@ if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.24.0)
 endif()
 
 # Archive
-set(RUNTIME_QEMU_ARCHIVE "" CACHE FILEPATH "QEMU Path")
+set(QEMU_ARCHIVE "qemu-9.2.0.tar.xz")
-if(NOT EXISTS "${RUNTIME_QEMU_ARCHIVE}")
+set(QEMU_HASH "f859f0bc65e1f533d040bbe8c92bcfecee5af2c921a6687c652fb44d089bd894")
-    message(FATAL_ERROR "Missing QEMU Archive!")
-endif()
 
 # Library
 set(QEMU_LIBRARY "/lib/libqemu-arm.so")
 
-# Build
+# Patches
-include(ExternalProject)
+set(PATCHES "${CMAKE_CURRENT_SOURCE_DIR}/patches")
+set(PATCH_CMD "patch" "-p1" "<")
+
+# PkgConfig
 set(PKGCONFIG_ENV "")
 if(DEFINED ENV{PKG_CONFIG_LIBDIR})
     set(PKGCONFIG_ENV "PKG_CONFIG_LIBDIR=$ENV{PKG_CONFIG_LIBDIR}")
 endif()
+
+# Build
+include(ExternalProject)
 ExternalProject_Add(qemu
-    URL "${RUNTIME_QEMU_ARCHIVE}"
+    URL "${CMAKE_CURRENT_SOURCE_DIR}/${QEMU_ARCHIVE}"
+    URL_HASH "SHA256=${QEMU_HASH}"
     # Configure Build
     CONFIGURE_COMMAND
         "${CMAKE_COMMAND}" "-E" "env"
         ${PKGCONFIG_ENV}
         "<SOURCE_DIR>/configure"
         "--prefix=<INSTALL_DIR>"
+        # Cross-Compile
         "--cross-prefix="
         "--cc=${CMAKE_C_COMPILER}"
         "--cxx=${CMAKE_CXX_COMPILER}"
+        # Optimize
         "--disable-debug-info"
         "--enable-strip"
         "--enable-pie"
-        "-Db_staticpic=true"
+        # Minimal Build
-        "-Db_lundef=false"
         "--target-list=arm-linux-user"
         "--without-default-features"
     USES_TERMINAL_CONFIGURE TRUE
     # Build Command
-    BUILD_COMMAND "ninja"
+    BUILD_COMMAND "ninja" "install"
-    COMMAND "ninja" "install"
     BUILD_BYPRODUCTS "<INSTALL_DIR>${QEMU_LIBRARY}"
     USES_TERMINAL_BUILD TRUE
     # Patch Command
-    PATCH_COMMAND "patch" "-p1" "<" "${CMAKE_CURRENT_SOURCE_DIR}/runtime.patch"
+    PATCH_COMMAND ${PATCH_CMD} "${PATCHES}/build-as-shared-library.patch"
+    COMMAND ${PATCH_CMD} "${PATCHES}/flatpak-support.patch"
+    COMMAND ${PATCH_CMD} "${PATCHES}/trampoline-syscall.patch"
     # Disable Install Command
     INSTALL_COMMAND ""
 )

qemu/patches/build-as-shared-library.patch

@@ -0,0 +1,49 @@
+--- a/linux-user/main.c
++++ b/linux-user/main.c
+@@ -671,7 +671,8 @@
+     return optind;
+ }
+
+-int main(int argc, char **argv, char **envp)
++#pragma GCC diagnostic ignored "-Wmissing-prototypes"
++int qemu_main(int argc, char **argv, char **envp)
+ {
+     struct target_pt_regs regs1, *regs = &regs1;
+     struct image_info info1, *info = &info1;
+--- a/meson.build
++++ b/meson.build
+@@ -1,6 +1,6 @@
+ project('qemu', ['c'], meson_version: '>=1.5.0',
+         default_options: ['warning_level=1', 'c_std=gnu11', 'cpp_std=gnu++11', 'b_colorout=auto',
+-                          'b_staticpic=false', 'stdsplit=false', 'optimization=2', 'b_pie=true'],
++                          'b_staticpic=true', 'stdsplit=false', 'optimization=2', 'b_pie=true'],
+         version: files('VERSION'))
+
+ meson.add_devenv({ 'MESON_BUILD_ROOT' : meson.project_build_root() })
+@@ -4015,14 +4014,13 @@
+       exe_name += '-unsigned'
+     endif
+
+-    emulator = executable(exe_name, exe['sources'],
++    emulator = library(exe_name, exe['sources'],
+                install: true,
+                c_args: c_args,
+                dependencies: arch_deps + exe['dependencies'],
+                objects: lib.extract_all_objects(recursive: true),
+                link_depends: [block_syms, qemu_syms],
+-               link_args: link_args,
+-               win_subsystem: exe['win_subsystem'])
++               link_args: link_args)
+
+     if host_os == 'darwin'
+       icon = 'pc-bios/qemu.rsrc'
+@@ -4166,9 +4164,7 @@
+
+ subdir('scripts')
+ subdir('tools')
+-subdir('pc-bios')
+ subdir('docs')
+-subdir('tests')
+ if gtk.found()
+   subdir('po')
+ endif

qemu/patches/flatpak-support.patch

@@ -0,0 +1,10 @@
+--- a/meson.build
++++ b/meson.build
+@@ -2613,7 +2613,6 @@
+ config_host_data.set('CONFIG_LINUX_MAGIC_H', cc.has_header('linux/magic.h'))
+ config_host_data.set('CONFIG_VALGRIND_H', cc.has_header('valgrind/valgrind.h'))
+ config_host_data.set('HAVE_BTRFS_H', cc.has_header('linux/btrfs.h'))
+-config_host_data.set('HAVE_DRM_H', cc.has_header('libdrm/drm.h'))
+ config_host_data.set('HAVE_OPENAT2_H', cc.has_header('linux/openat2.h'))
+ config_host_data.set('HAVE_PTY_H', cc.has_header('pty.h'))
+ config_host_data.set('HAVE_SYS_DISK_H', cc.has_header('sys/disk.h'))

qemu/patches/trampoline-syscall.patch

@@ -0,0 +1,31 @@
+--- a/meson.build
++++ b/meson.build
+@@ -1,5 +1,5 @@
+ project('qemu', ['c'], meson_version: '>=1.5.0',
+-        default_options: ['warning_level=1', 'c_std=gnu11', 'cpp_std=gnu++11', 'b_colorout=auto',
++        default_options: ['warning_level=1', 'c_std=gnu11', 'cpp_std=gnu++11', 'b_colorout=auto', 'b_lundef=false',
+                           'b_staticpic=true', 'stdsplit=false', 'optimization=2', 'b_pie=true'],
+         version: files('VERSION'))
+
+--- a/linux-user/syscall.c
++++ b/linux-user/syscall.c
+@@ -9077,6 +9077,8 @@
+            int, __to_dfd, const char *, __to_pathname, unsigned int, flag)
+ #endif
+
++extern int trampoline_handle_syscall(int32_t num, uint32_t arg1, uint32_t arg2);
++
+ /* This is an internal helper for do_syscall so that it is easier
+  * to have a single return point, so that actions, such as logging
+  * of syscall results, can be performed.
+@@ -9101,6 +9103,10 @@
+ #endif
+     void *p;
+
++    if (trampoline_handle_syscall(num, arg1, arg2)) {
++        return 0;
++    }
++
+     switch(num) {
+     case TARGET_NR_exit:
+         /* In old applications this may be used to implement _exit(2).

qemu/runtime.patch

@@ -1,71 +0,0 @@
---- a/linux-user/main.c
-+++ b/linux-user/main.c
-@@ -671,7 +671,8 @@
-     return optind;
- }
-
--int main(int argc, char **argv, char **envp)
-+#pragma GCC diagnostic ignored "-Wmissing-prototypes"
-+int qemu_main(int argc, char **argv, char **envp)
- {
-     struct target_pt_regs regs1, *regs = &regs1;
-     struct image_info info1, *info = &info1;
---- a/linux-user/syscall.c
-+++ b/linux-user/syscall.c
-@@ -9077,6 +9077,8 @@
-            int, __to_dfd, const char *, __to_pathname, unsigned int, flag)
- #endif
-
-+extern int trampoline_handle_syscall(int32_t num, uint32_t arg1, uint32_t arg2);
-+
- /* This is an internal helper for do_syscall so that it is easier
-  * to have a single return point, so that actions, such as logging
-  * of syscall results, can be performed.
-@@ -9101,6 +9103,10 @@
- #endif
-     void *p;
-
-+    if (trampoline_handle_syscall(num, arg1, arg2)) {
-+        return 0;
-+    }
-+
-     switch(num) {
-     case TARGET_NR_exit:
-         /* In old applications this may be used to implement _exit(2).
---- a/meson.build
-+++ b/meson.build
-@@ -2470,7 +2470,6 @@
- config_host_data.set('CONFIG_LINUX_MAGIC_H', cc.has_header('linux/magic.h'))
- config_host_data.set('CONFIG_VALGRIND_H', cc.has_header('valgrind/valgrind.h'))
- config_host_data.set('HAVE_BTRFS_H', cc.has_header('linux/btrfs.h'))
--config_host_data.set('HAVE_DRM_H', cc.has_header('libdrm/drm.h'))
- config_host_data.set('HAVE_PTY_H', cc.has_header('pty.h'))
- config_host_data.set('HAVE_SYS_DISK_H', cc.has_header('sys/disk.h'))
- config_host_data.set('HAVE_SYS_IOCCOM_H', cc.has_header('sys/ioccom.h'))
-@@ -4015,14 +4014,13 @@
-       exe_name += '-unsigned'
-     endif
-
--    emulator = executable(exe_name, exe['sources'],
-+    emulator = library(exe_name, exe['sources'],
-                install: true,
-                c_args: c_args,
-                dependencies: arch_deps + exe['dependencies'],
-                objects: lib.extract_all_objects(recursive: true),
-                link_depends: [block_syms, qemu_syms],
--               link_args: link_args,
--               win_subsystem: exe['win_subsystem'])
-+               link_args: link_args)
-
-     if host_os == 'darwin'
-       icon = 'pc-bios/qemu.rsrc'
-@@ -4166,9 +4164,7 @@
-
- subdir('scripts')
- subdir('tools')
--subdir('pc-bios')
- subdir('docs')
--subdir('tests')
- if gtk.found()
-   subdir('po')
- endif

src/log.h

@@ -4,7 +4,7 @@
 #include <cstdlib>
 
 #define ERR(format, ...) \
-    { \
+    ({ \
         fprintf(stderr, "RUNTIME ERROR: " format "\n", ##__VA_ARGS__); \
         exit(EXIT_FAILURE); \
-    }
+    })