box86/docs/USAGE.md

Usage

There are many environment variables to control Box86 behaviour.

BOX86_LOG

Controls the Verbosity level of the logs

• 0: NONE : No message (except some fatal error). (Default.)
• 1: INFO : Show some minimum log (Example: librairies not found)
• 2: DEBUG : Details a lot of stuff (Example: relocations or functions called).
• 3: DUMP : All DEBUG plus DUMP of all ELF Info (so same as BOX86_LOG=2 BOX86_DUMP=1)

BOX86_DUMP

Controls the Dump of elf content

• 0: No dump of elf information (Default)
• 1: Dump elf sections and relocations and other information (also active if using BOX86_LOG=3)

BOX86_NOBANNER

Disables Box86 printing its version and build

• 0 : Enable printing its banner. (Default.)
• 1 : Disable printing its banner.

BOX86_LD_LIBRARY_PATH

Path to look for x86 libraries. Default is current folder and lib in current folder. Also, /usr/lib/i386-linux-gnu and /lib/i386-linux-gnu are added if they exist.

BOX86_PATH

Path to look for x86 executable. Default is current folder and bin in current folder.

BOX86_DLSYM_ERROR

Enables/Disables the logging of dlsym errors.

• 0 : Don't log dlsym errors. (Default.)
• 1 : Log dlsym errors.

BOX86_TRACE_FILE

Send all log and trace to a file instead of stdout Also, if name contains %pid then this is replaced by the actual PID of box86 instance Use stderr to use this instead of default stdout

BOX86_TRACE

Only on build with trace enabled. Trace allow the logging of all instruction executed, along with register dump

• 0 : No trace. (Default.)
• 1 : Trace enabled. Trace start after the initialisation of all depending libraries is done.
• symbolname : Trace only symbolname (trace is disable if the symbol is not found).
• 0xXXXXXXX-0xYYYYYYY : Trace only between the 2 addresses.

BOX86_TRACE_INIT

Use BOX86_TRACE_INIT instead of BOX_TRACE to start trace before the initialisation of libraries and the running program

• 0 : No trace. (Default.)
• 1 : Trace enabled. The trace start with the initialisation of all depending libraries is done.

BOX86_TRACE_START

Only on builds with trace enabled.

• NNNNNNN : Start trace only after NNNNNNNN opcode execute (number is an uint64_t).

BOX86_TRACE_XMM

Only on builds with trace enabled.

• 0 : The XMM (i.e. SSE/SSE2) register will not be logged with the general and x86 registers. (Default.)
• 1 : Dump the XMM registers.

BOX86_LOAD_ADDR

Try to load at 0xXXXXXX main binary (if binary is a PIE)

• 0xXXXXXXXX : The load address . (Only active on PIE programs.)

BOX86_NOSIGSEGV

Disable handling of SigSEGV. (Very useful for debugging.)

• 0 : Let the x86 program set sighandler for SEGV (Default.)
• 1 : Disable the handling of SigSEGV.

BOX86_NOSIGILL

Disable handling of SigILL (to ease debugging mainly).

• 0 : Let x86 program set sighandler for Illegal Instruction
• 1 : Disables the handling of SigILL

BOX86_X11COLOR16

PANDORA only: Try converting X11 color from 32 bits to 16 bits (to avoid light green on light cyan windows).

• 0 : Don't touch X11 colors. (Default.)
• 1 : Change colors arguments in XSetForeground, XSetBackground and XCreateGC.

BOX86_X11THREADS

Call XInitThreads when loading X11. (This is mostly for old Loki games with the Loki_Compat library.)

• 0 : Don't force call XInitThreads. (Default.)
• 1 : Call XInitThreads as soon as libX11 is loaded.

BOX86_X11GLX

Force libX11's GLX extension to be present.

• 0 : Do not force libX11's GLX extension to be present.
• 1 : GLX will always be present when using XQueryExtension. (Default.)

BOX86_DYNAREC_DUMP

Enables/disables Box86's Dynarec's dump.

• 0 : Disable Dynarec's blocks dump. (Default.)
• 1 : Enable Dynarec's blocks dump.
• 2 : Enable Dynarec's blocks dump with some colors.

BOX86_DYNAREC_LOG

Set the level of DynaRec's logs.

• 0 : NONE : No Logs for DynaRec. (Default.)
• 1 :INFO : Minimum Dynarec Logs (only unimplemented OpCode).
• 2 : DEBUG : Debug Logs for Dynarec (with details on block created / executed).
• 3 : VERBOSE : All of the above plus more.

BOX86_DYNAREC

Enables/Disables Box86's Dynarec.

• 0 : Disables Dynarec.
• 1 : Enable Dynarec. (Default.)

BOX86_DYNAREC_TRACE

Enables/Disables trace for generated code.

• 0 : Disable trace for generated code. (Default.)
• 1 : Enable trace for generated code (like regular Trace, this will slow down the program a lot and generate huge logs).

BOX86_NODYNAREC

Forbid dynablock creation in the interval specified (helpfull for debugging behaviour difference between Dynarec and Interpretor)

• 0xXXXXXXXX-0xYYYYYYYY : define the interval where dynablock cannot start (inclusive-exclusive)

BOX86_DYNAREC_BIGBLOCK

Enables/Disables Box86's Dynarec building BigBlock.

• 0 : Don't try to build block as big as possible (can help program using lots of thread and a JIT, like C#/Unity) (Default when libmonobdwgc-2.0.so is loaded)
• 1 : Build Dynarec block as big as possible (Default.)
• 2 : Build Dynarec block bigger (don't stop when block overlaps)

BOX86_DYNAREC_STRONGMEM

Enable/Disable simulation of Strong Memory model

• 0 : Don't try anything special (Default.)
• 1 : Enable some Memory Barrier when reading from memory (on some MOV opcode) to simulate Strong Memory Model while trying to limit performance impact (Default when libmonobdwgc-2.0.so is loaded)
• 2 : Enable some Memory Barrier when reading from memory (on some MOV opcode) to simulate Strong Memory Model

BOX86_DYNAREC_X87DOUBLE

Force the use of Double for x87 emulation

• 0 : Try to use float when possible for x87 emulation (faster)
• 1 : Only use Double for x87 emulation (slower, may be needed for some specific games, like Crysis)

BOX86_DYNAREC_FASTNAN

Enable/Disable generation of -NAN

• 0 : Generate -NAN like on x86 (slower, more x86 accurate)
• 1 : Don't do anything special with NAN, to go as fast as possible (Default)

BOX86_LIBGL

• libXXXX set the name for libGL (defaults to libGL.so.1).
• /PATH/TO/libGLXXX : Sets the name and path for libGL You can also use SDL_VIDEO_GL_DRIVER

BOX86_LD_PRELOAD

• XXXX[:YYYYY] force loading XXXX (and YYYY...) libraries with the binary PreLoaded libs can be emulated or native, and are treated the same way as if they were comming from the binary

BOX86_EMULATED_LIBS

• XXXX[:YYYYY] force lib XXXX (and YYYY...) to be emulated (and not wrapped) Some games uses an old version of some libraries, with an ABI incompatible with native version. Note that LittleInferno for example is auto detected, and libvorbis.so.0 is automatical added to emulated libs, and same for Don't Starve (and Together / Server variant) that use an old SDL2 too

BOX86_ALLOWMISSING_LIBS

Allow Box86 to continue even if a library is missing (renamed from BOX86_ALLOWMISSINGLIBS).

• 0 : Box86 will stop if a library cannot be loaded. (Default.)
• 1 : Continue even if a needed library cannot be loaded. Unadvised, this will, in most cases, crash later on.

BOX86_ALLOWMISSING_SYMBOLS

Allow dlopen with RTLD_NOW flag to not resolve all symbols.

• 0 : Box86 will stop if a library have unresolved symbols. (Default.)
• 1 : Continue even if a needed library have unresolved symbols (like symbols not yet wrapped).

BOX86_PREFER_WRAPPED

Box86 will use wrapped libs even if the lib is specified with absolute path

• 0 : Try to use emulated libs when they are defined with absolute path (Default.)
• 1 : Use Wrapped native libs even if path is absolute

BOX86_PREFER_EMULATED

Box86 will prefer emulated libs first (execpt for glibc, alsa, pulse, GL, vulkan and X11

• 0 : Native libs are prefered (Default.)
• 1 : Emulated libs are prefered (Default for program running inside pressure-vessel)

BOX86_NOPULSE

Disables the load of pulseaudio libraries.

• 0 : Load pulseaudio libraries if found. (Default.)
• 1 : Disables the load of pulse audio libraries (libpulse and libpulse-simple), both the native library and the x86 library

BOX86_NOGTK

Disables the loading of wrapped GTK libraries.

• 0 : Load wrapped GTK libraries if found. (Default.)
• 1 : Disables loading wrapped GTK libraries.

BOX86_NOVULKAN

Disables the load of vulkan libraries.

• 0 : Load vulkan libraries if found.
• 1 : Disables the load of vulkan libraries, both the native and the i386 version (can be useful on Pi4, where the vulkan driver is not quite there yet.)

BOX86_ENV

• XXX=yyyy will add XXX=yyyy env. var.

BOX86_ENV1

• XXX=yyyy will add XXX=yyyy env. var. and continue with BOX86_ENV2 ... until var doesn't exist

BOX86_FIX_64BIT_INODES

Fix/Don't fix 64bit inodes

• 0 : Don't fix 64bit inodes. (Default.)
• 1 : Fix 64bit inodes. Helps when running on Filesystems with 64bit inodes. Is useful when a program uses API functions which doesn't support it and the program doesn't use inodes information.

BOX86_SHOWSEGV

Show Segfault signal even if a signal handler is present

• 0 : Don't force segfault details when a signal handler is install (Default, to limit message spamming)
• 1 : Show segfault details

BOX86_BACKTRACE

Show a backtrace (native and emulated) on Signal

• 0 : Don't show any backtrace (Default.)
• 1 : Show native backtrace when a signal is dumped (not available on Andoid build)

BOX86_BASH

Define x86 bash to launch script

• yyyy Will use yyyy as x86 bash to launch script. yyyy needs to be a full path to a valid x86 version of bash. Note that is Box64 is available, an x86_64 version of bash can also be used. Also, BOX64_BASH env. var. will also be read if BOX86_BASH is not defined.

BOX86_BOX64

Define where to find box64 binary

• yyyy Will use yyyy as x86_64 interpretor, to launch x64_64 binaries

BOX86_JITGDB

• 0 : Just print the Segfault message on segfault (default)
• 1 : Launch gdb when a segfault, bus error or illegal instruction signal is trapped, attached to the offending process and go in an endless loop, waiting. When in gdb, you need to find the correct thread yourself (the one with my_box86signalhandler in is stack) then probably need to finish 1 or 2 functions (inside usleep(..)) and then you'll be in my_box86signalhandler, just before the printf of the Segfault message. Then simply set waiting=0 to exit the infinite loop.
• 2 : Launch gdbserver when a segfault, bus error or illegal instruction signal is trapped, attached to the offending process, and go in an endless loop, waiting. Use gdb /PATH/TO/box86 and then target remote 127.0.0.1:1234 to connect to the gdbserver (or use actual IP if not on the machine). After that, the procedure is the same as with BOX86_JITGDB=1. This mode can be usefullwhen programs redirect all console output to a file (like Unity3D Games)