add functions <signal.h> , getenv/system (node.js)<stdlib> #3948

ghost · 2015-12-02T15:42:56Z

library.js , add system

i have updated in my branch library.js
to implement : system <stdlib.h>
it works on node.js
usage :

system ( "dir" ) ; 
system ( "node -v" ) ;
system ( "dir c:\\windows" );
system ( "em++ node001-getenv.cpp -o main.js" );

emscripten.h , add getenv

i have addedd getenv command <stlib.h>,,
it work on node.js
usage :

 char *s = getenv ( process.env.APPDATA );
 printf ( "\n NODE.JS <%s> " ,s  ) ; 
 printf ( "\n NODE.JS <%s> " , getenv ( process.env.HOMEDRIVE ) ) ;
 printf ( "\n NODE.JS <%s> " , getenv ( process.env ) ) ;

emscrpiten.h, added pause

raise SIGSTOP and SIGCONT;
usage :
pause(1000);

emscripten.h, added MACRO

__SIGRTMIN
__SIGRTMAX

to implement other two function :

__libc_current_sigrtmax
__libc_current_sigrtmin

library.signal.js

addedd :

signal , raise , pause ,
sigprocmask , __libc_current_sigrtmax ,
__libc_current_sigrtmin

example

add example, for this command , in tests :

node001-getenv.cpp
node002-system.cpp
signal001-signal-raise.cpp
signal002-pause.cpp
signal003-sigprocmask.cpp

implemented getenv on node.js check memory leaks : printf ( "\n NODE.JS <%s> " ,getenv ( process.env.APPDATA ) ) ;

implemented : system command, works on node.js : usage : system ( "dir" ) ; system ( "node -v" ) ; system ( "dir c:\\windows" ); system ( "em++ node001-getenv.cpp -o main.js" );

added get env added pause added __SIGRTMIN added __SIGRTMAX

add signal , raise , pause , sigprocmask, __libc_current_sigrtmax __libc_current_sigrtmin

create example for getenv node.js

add example to use system command on node.js

show usage of signal raise

add usage for pause() command

usage sig proc mask

kripken · 2015-12-03T01:56:59Z

src/library.js

-    // Can't call external programs.
-    ___setErrNo(ERRNO_CODES.EAGAIN);
-    return -1;
+  system: function(command) 


our convention has the { on the same line

ok i can repost you a code align ,with emscripten guide lines
{ in the same lines,

apply { in the same lines and tab code with 2 spaces

ghost · 2015-12-03T18:40:26Z

i need you ask a question : about free() . I have seen that this function
is not implemented yet, but counterpart in library.js _free, works good .
are there issues to implement correctly ?

if environmet is node

kripken · 2015-12-14T22:48:45Z

free is implemented in system/lib/dlmalloc.c.

ghost · 2015-12-15T13:42:47Z

you're right
i have removed , getenv from emscipten.h

remove getnev implementation on emscripten.h. file to avoid confusion.

ghost · 2015-12-16T13:46:26Z

yes, but if you try this code, free does not work :

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <emscripten.h>

int main ( void )
{
    // ************************************** free do not free
    char *s1 = (char*) malloc ( 256 );
    strcpy ( s1,"Hello\0" ) ;
    puts (s1);
    free(s1);
    puts(s1);

    // ************************************** free do not free
    char *s2  = (char* )EM_ASM_INT ( {
        var p = Module._malloc(256);
        setValue ( p + 0 , 65 , 'i8' ) ; // A
        setValue ( p + 1 , 66 , 'i8' ) ; // B
        setValue ( p + 2 , 67 , 'i8' ) ; // C
        setValue ( p + 3 , 0  , 'i8' ) ;
        return p ;
        } , NULL );
    puts(s2);
    free(s2);   // do not free
    puts(s2);

    // ************************************** _free do free
    /*
    EM_ASM_INT ( {
    return _free ( $0  );
    }, s1 ) ;
    EM_ASM_INT ( {
    return _free ( $0  );
    }, s1 ) ;
    */
    puts(s1);
    puts(s2);


    char * s3 = (char*) EM_ASM_INT ( {
        var  str = 'ciao' ;
        var  ret  = allocate(intArrayFromString(str), 'i8', ALLOC_NORMAL);
        return  ret ;
    }, NULL  ) ;

    puts( s3 ) ;
    free(s3); // do not free
    puts( s3 ) ;

    // ************************************** _free do free
    /*
    EM_ASM_INT ( {
        return _free ( $0  );
    }, s3 ) ;
    */
    puts( s3 ) ;

    return 0 ;
}

kripken · 2015-12-21T19:19:37Z

I don't understand, what do you mean by "free does not free"?

ghost · 2015-12-21T19:55:40Z

the command ' free ' does not release the allocated memory

2015-12-21 20:22 GMT+01:00 Alon Zakai [email protected]:

I don't understand, what do you mean by "free does not free"?

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#3948 (comment).

ghost · 2015-12-24T13:35:54Z

Happy Christmas Kripken !

2015-12-21 20:55 GMT+01:00 claudio daffra [email protected]:

the command ' free ' does not release the allocated memory

2015-12-21 20:22 GMT+01:00 Alon Zakai [email protected]:

I don't understand, what do you mean by "free does not free"?

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#3948 (comment).

kripken · 2016-01-07T00:53:43Z

Sorry for the delay here.

I still don't follow. How do you know it isn't freeing the memory?

ghost · 2016-01-09T15:43:04Z

excuse me, for my bad english
i'll post an issue soon
with more clarifications
regards Claudio

2016-01-07 1:54 GMT+01:00 Alon Zakai [email protected]:

Sorry for the delay here.

I still don't follow. How do you know it isn't freeing the memory?

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#3948 (comment).

kripken · 2018-11-02T20:37:47Z

This PR is quite old, closing. Feel free to reopen if still relevant.

IngwiePhoenix · 2020-12-12T17:58:57Z

Pretty sure I'll be poking a dead issue here.

I am poking around with WebAssembly and I want to access variables from the real environment - well, not me specificaly, but SWIG would like to. I run it via Node.

Studying the settings.js file containing several of the -s options, I came up with this configuration command:

$ /opt/emsdk/upstream/emscripten/emconfigure ./configure \
  CC=/opt/emsdk/upstream/emscripten/emcc \
  CXX=/opt/emsdk/upstream/emscripten/em++ \
  --without-pcre \
  LDFLAGS="-s ASSERTIONS=1 -lnodefs.js -s EXIT_RUNTIME=1 -s ALLOW_MEMORY_GROWTH=1 -s ALLOW_TABLE_GROWTH=1 -s ENVIRONMENT=node -s NODERAWFS=1 -s SUPPORT_ERRNO=1"

So far, so good. Passing environment variables though does not work unfortunately. Has a streamlined method of using environment variables been introduced in the meantime? Thanks!

sbc100 · 2020-12-12T18:06:14Z

Emscripten seeds its environment from the ENV JavaScript variable. This works the same on the web as under node.

If you would like to node-specific behaviour to mirror the real environment, and that is genuinely useful, and I think we would accept such a patch. But these change of changes that are node-specific can also hurt portability so we should consider them carefully.

IngwiePhoenix · 2020-12-12T18:20:37Z

Why not go for an option like -s NODERAWFS=1 - but for the environment? This option already makes it very obvious that it is node-specific. Alternatively, would there be a way to "link" this behaviour in? I saw the pre-/post-js but don't have a full idea of how I could use those to essentially for(var k in process.env) { ENV[k] = process.env[k]; }.

sbc100 · 2020-12-12T19:12:11Z

Sure either of those approaches would work.

That for loop in pre-js should work yes.

IngwiePhoenix · 2020-12-13T16:13:43Z

Had no luck so far. But I did find this:

  function getEnvStrings() {
      if (!getEnvStrings.strings) {
        // Default values.
        // Browser language detection #8751
        var lang = ((typeof navigator === 'object' && navigator.languages && navigator.languages[0]) || 'C').replace('-', '_') + '.UTF-8';
        var env = {
          'USER': 'web_user',
          'LOGNAME': 'web_user',
          'PATH': '/',
          'PWD': '/',
          'HOME': '/home/web_user',
          'LANG': lang,
          '_': getExecutableName()
        };
        // Apply the user-provided values, if any.
        for (var x in ENV) {
          env[x] = ENV[x];
        }
        var strings = [];
        for (var x in env) {
          strings.push(x + '=' + env[x]);
        }
        getEnvStrings.strings = strings;
      }
      return getEnvStrings.strings;
    }

The way pre-js is positioned, there is no viable solution to modify getEnvStrings at all to just reference process.env. In fact, if this behaviour was changed to something like this:

if(ENVIRONMENT_IS_NODE) {
  getEnvStrings.strings = process.env;
} else { /* ...implement the "standard" env as seen above. */ }

then getenv and friends would happily read and respond with the actual system environment.

Looks like my best bet at this point is to look where this is generated and how I can change/update that and maybe make it a PR or something. But for now, I am a little lost as to how I can just add this feature without neccessarily modifying the Emscripten source.

IngwiePhoenix · 2020-12-13T16:26:52Z

Well, I did find a method. Hacky, but for now, works.

LDFLAGS appended: --pre-js (pwd)/env-init.js -s INCOMING_MODULE_JS_API="['preRun']"
env-init.js:

Module.preRun = function customPreRun() {
  ENV = Object.create(process.env);
}

This allows this program to display the proper PATH:

#include <stdio.h>
#include <stdlib.h>
int main() { puts(getenv("PATH")); }

Not elegant but working. Wish there was an easier way to get this working, considering it's literally a one-liner. XD

ClaudioDaffra added 11 commits November 24, 2015 18:44

Node.js getenv

b08065e

implemented getenv on node.js check memory leaks : printf ( "\n NODE.JS <%s> " ,getenv ( process.env.APPDATA ) ) ;

Update library.js

f3a263d

Update library.js

0b7f5ff

implemented : system command, works on node.js : usage : system ( "dir" ) ; system ( "node -v" ) ; system ( "dir c:\\windows" ); system ( "em++ node001-getenv.cpp -o main.js" );

Update emscripten.h

0ccfbb7

added get env added pause added __SIGRTMIN added __SIGRTMAX

Update library_signals.js :

8381081

add signal , raise , pause , sigprocmask, __libc_current_sigrtmax __libc_current_sigrtmin

node.js - getenv

b5141ee

create example for getenv node.js

node.js - system

dc44c17

add example to use system command on node.js

signal - raise example

8780ca6

show usage of signal raise

create pause command example

c76e3d7

add usage for pause() command

Create sigprocmask example

f350dd4

usage sig proc mask

update example

9add527

ghost mentioned this pull request Dec 2, 2015

Direct environment access on node.js #3915

Open

kripken reviewed Dec 3, 2015
View reviewed changes

ClaudioDaffra added 2 commits December 3, 2015 14:19

Update .js { ident 2 space

b4f2179

apply { in the same lines and tab code with 2 spaces

tab rialligned

8723097

update system

ceecd8f

if environmet is node

remove get env (node.js)

3e60568

remove getnev implementation on emscripten.h. file to avoid confusion.

RReverser mentioned this pull request Feb 13, 2017

Compiletest doesn't pass environment variables to emscripten tests rust-lang/rust#31622

Open

kripken closed this Nov 2, 2018

kleisauke mentioned this pull request Nov 10, 2023

Mirror entire environment under node #18820

Open

add functions <signal.h> , getenv/system (node.js)<stdlib> #3948

add functions <signal.h> , getenv/system (node.js)<stdlib> #3948

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ghost commented Dec 2, 2015

library.js , add system

emscripten.h , add getenv

emscrpiten.h, added pause

emscripten.h, added MACRO

library.signal.js

example

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