Working with pipes

[Anton Kochkov]

Hello everyone!

I am writing a pipe interface to radare2 and currently I have this code:

:- use_module(library(unix)).

:- use_module(library(process)).

:- use_module(library(http/json)).

read_result(Out, Json) :-

%read_string(Out, "", "", End, Json),

%print(Json).

json_read_dict(Out, Json).

send_command(R, Command, Json) :-

write(R.in, Command),

nl(R.in),

flush_output(R.in),

read_result(R.out, Json).

% create structure with pid and in/out pipes

open_file(File, R) :-

process_create(path(radare2),

% r2 -2 -q0 file

["-2", "-q0", file(File)],

[stdin(pipe(In)),

stdout(pipe(Out)),

process(Pid)]),

dict_create(R, r2instance, [pid:Pid,in:In,out:Out]).

% TODO: Make more graceful exit

close_instance(R) :-

close(R.in),

close(R.out),

process_kill(R.pid).

with_command(File, Command, O) :-

open_file(File, R),

send_command(R, Command, O),

close_instance(R).

The problem if I evaluate it it complains of the invalid JSON, while for other tools it is valid JSON: [r2pipe.prolog]$ swipl r2pipe.pl Welcome to SWI-Prolog (threaded, 64 bits, version 7.6.4) SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software. Please run ?- license. for legal details.   For online help and background, visit http://www.swi-prolog.org For built-in help, use ?- help(Topic). or ?- apropos(Word).   ?- with_command("/bin/ls", "ij", O). ERROR: Stream <stream>(0xa16800):1:2 Syntax error: json(illegal_json) ?- % halt If I change the "read_result" relation to: read_result(Out, Json) :-     read_string(Out, "", "", End, Json),     print(Json). It prints JSON here:   [r2pipe.prolog]$ swipl r2pipe.pl Warning: /home/user/radare/r2pipe.prolog/r2pipe.pl:6:         Singleton variables: [End] Welcome to SWI-Prolog (threaded, 64 bits, version 7.6.4) SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software. Please run ?- license. for legal details.   For online help and background, visit http://www.swi-prolog.org For built-in help, use ?- help(Topic). or ?- apropos(Word).   ?- with_command("/bin/ls", "ij", O). "{\"core\":{\"type\":\"DYN (Shared object file)\",\"file\":\"/bin/ls\",\"fd\":3,\"size\":157896,\"humansz\":\"154.2K\",\"iorw\":false,\"mode\":\"r-x\",\"obsz\":0,\"block\":256,\"format\":\"elf64\"},\"bin\":{\"arch\":\"x86\",\"binsz\":155969,\"bintype\":\"elf\",\"bits\":64,\"canary\":true,\"class\":\"ELF64\",\"compiled\":\"\",\"crypto\":false,\"dbg_file\":\"\",\"endian\":\"little\",\"havecode\":true,\"guid\":\"\",\"intrp\":\"/lib64/ld-linux-x86-64.so.2\",\"lang\":\"c\",\"linenum\":false,\"lsyms\":false,\"machine\":\"AMD x86-64 architecture\",\"maxopsz\":16,\"minopsz\":1,\"nx\":true,\"os\":\"linux\",\"pcalign\":0,\"pic\":true,\"relocs\":false,\"relro\":\"full\",\"rpath\":\"NONE\",\"static\":false,\"stripped\":true,\"subsys\":\"linux\",\"va\":true,\"checksums\":{}}}\n" O = "{\"core\":{\"type\":\"DYN (Shared object file)\",\"file\":\"/bin/ls\",\"fd\":3,\"size\":157896,\"humansz\":\"154.2K\",\"iorw\":false,\"mode\":\"r-x\",\"obsz\":0,\"block\":256,\"format\":\"elf64\"},\"bin\":{\"arch\":\"x86\",\"binsz\":155969,\"bintype\":\"elf\",\"bits\":64,\"canary\":true,\"class\":\"ELF64\",\"compiled\":\"\",\"crypto\":false,\"dbg_file\":\"\",\"endian\":\"little\",\"havecode\":true,\"guid\":\"\",\"intrp\":\"/lib64/ld-linux-x86-64.so.2\",\"lang\":\"c\",\"linenum\":false,\"lsyms\":false,\"machine\":\"AMD x86-64 architecture\",\"maxopsz\":16,\"minopsz\":1,\"nx\":true,\"os\":\"linux\",\"pcalign\":0,\"pic\":true,\"relocs\":false,\"relro\":\"full\",\"rpath\":\"NONE\",\"static\":false,\"stripped\":true,\"subsys\":\"linux\",\"va\":true,\"checksums\":{}}}\n".

Not sure what is exactly wrong with this JSON then

File itself here https://github.com/XVilka/r2pipe.prolog/blob/master/r2pipe.pl