github.com/guyezi/gofrontend@v0.0.0-20200228202240-7a62a49e62c0/libgo/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 hurd linux nacl netbsd openbsd solaris windows
     6  
     7  #include "runtime.h"
     8  #include "array.h"
     9  #include "arch.h"
    10  
    11  extern Slice runtime_get_envs(void);
    12  
    13  String
    14  runtime_getenv(const char *s)
    15  {
    16  	int32 i, j;
    17  	intgo len;
    18  	const byte *v, *bs;
    19  	Slice envs;
    20  	String* envv;
    21  	int32 envc;
    22  	String ret;
    23  
    24  	bs = (const byte*)s;
    25  	len = runtime_findnull(bs);
    26  	envs = runtime_get_envs();
    27  	envv = (String*)envs.__values;
    28  	envc = envs.__count;
    29  	for(i=0; i<envc; i++){
    30  		if(envv[i].len <= len)
    31  			continue;
    32  		v = (const byte*)envv[i].str;
    33  		for(j=0; j<len; j++)
    34  			if(bs[j] != v[j])
    35  				goto nomatch;
    36  		if(v[len] != '=')
    37  			goto nomatch;
    38  		ret.str = v+len+1;
    39  		ret.len = envv[i].len-len-1;
    40  		return ret;
    41  	nomatch:;
    42  	}
    43  	ret.str = nil;
    44  	ret.len = 0;
    45  	return ret;
    46  }