Function builtin_shell

src/engine/builtins.cpp:2399–2478

LIST * builtin_shell( FRAME * frame, int flags )
{
    LIST   * command = lol_get( frame->args, 0 );
    LIST   * result = L0;
    string   s;
    int32_t ret;
    char     buffer[ 1024 ];
    FILE   * p = NULL;
    int      exit_status = -1;
    int      exit_status_opt = 0;
    int      no_output_opt = 0;
    int      strip_eol_opt = 0;

    /* Process the variable args options. */
    {
        int a = 1;
        LIST * arg = lol_get( frame->args, a );
        for ( ; !list_empty( arg ); arg = lol_get( frame->args, ++a ) )
        {
            if ( !strcmp( "exit-status", object_str( list_front( arg ) ) ) )
                exit_status_opt = 1;
            else if ( !strcmp( "no-output", object_str( list_front( arg ) ) ) )
                no_output_opt = 1;
            else if ( !strcmp("strip-eol", object_str( list_front( arg ) ) ) )
                strip_eol_opt = 1;
        }
    }

    /* The following fflush() call seems to be indicated as a workaround for a
     * popen() bug on POSIX implementations related to synhronizing input
     * stream positions for the called and the calling process.
     */
    fflush( NULL );

    p = popen( object_str( list_front( command ) ), "r" );
    if ( p == NULL )
        return L0;

    string_new( &s );

    while ( ( ret = int32_t(fread( buffer, sizeof( char ), sizeof( buffer ) - 1, p )) ) >
        0 )
    {
        buffer[ ret ] = 0;
        if ( !no_output_opt )
        {
            string_append( &s, buffer );
        }

        /* Explicit EOF check for systems with broken fread */
        if ( feof( p ) ) break;
    }

    if ( strip_eol_opt )
        string_rtrim( &s );

    exit_status = pclose( p );