github.com/rohankumardubey/syslog-redirector-golang@v0.0.0-20140320174030-4859f03d829a/src/pkg/runtime/env_posix.c (about)

     1  // Copyright 2012 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // +build darwin dragonfly freebsd linux netbsd openbsd windows
     6  
     7  #include "runtime.h"
     8  
     9  Slice syscall·envs;
    10  
    11  byte*
    12  runtime·getenv(int8 *s)
    13  {
    14  	int32 i, j;
    15  	intgo len;
    16  	byte *v, *bs;
    17  	String* envv;
    18  	int32 envc;
    19  
    20  	bs = (byte*)s;
    21  	len = runtime·findnull(bs);
    22  	envv = (String*)syscall·envs.array;
    23  	envc = syscall·envs.len;
    24  	for(i=0; i<envc; i++){
    25  		if(envv[i].len <= len)
    26  			continue;
    27  		v = envv[i].str;
    28  		for(j=0; j<len; j++)
    29  			if(bs[j] != v[j])
    30  				goto nomatch;
    31  		if(v[len] != '=')
    32  			goto nomatch;
    33  		return v+len+1;
    34  	nomatch:;
    35  	}
    36  	return nil;
    37  }
    38  
    39  void (*_cgo_setenv)(byte**);
    40  
    41  // Update the C environment if cgo is loaded.
    42  // Called from syscall.Setenv.
    43  void
    44  syscall·setenv_c(String k, String v)
    45  {
    46  	byte *arg[2];
    47  
    48  	if(_cgo_setenv == nil)
    49  		return;
    50  
    51  	arg[0] = runtime·malloc(k.len + 1);
    52  	runtime·memmove(arg[0], k.str, k.len);
    53  	arg[0][k.len] = 0;
    54  
    55  	arg[1] = runtime·malloc(v.len + 1);
    56  	runtime·memmove(arg[1], v.str, v.len);
    57  	arg[1][v.len] = 0;
    58  
    59  	runtime·asmcgocall((void*)_cgo_setenv, arg);
    60  	runtime·free(arg[0]);
    61  	runtime·free(arg[1]);
    62  }