curl/lib/getenv.c

78 строки
2.2 KiB
C

/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at https://curl.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
***************************************************************************/
#include "curl_setup.h"
#include <curl/curl.h>
#include "curl_memory.h"
#include "memdebug.h"
static char *GetEnv(const char *variable)
{
#if defined(_WIN32_WCE) || defined(CURL_WINDOWS_APP)
(void)variable;
return NULL;
#elif defined(WIN32)
/* This uses Windows API instead of C runtime getenv() to get the environment
variable since some changes aren't always visible to the latter. #4774 */
char *buf = NULL;
char *tmp;
DWORD bufsize;
DWORD rc = 1;
const DWORD max = 32768; /* max env var size from MSCRT source */
for(;;) {
tmp = realloc(buf, rc);
if(!tmp) {
free(buf);
return NULL;
}
buf = tmp;
bufsize = rc;
/* It's possible for rc to be 0 if the variable was found but empty.
Since getenv doesn't make that distinction we ignore it as well. */
rc = GetEnvironmentVariableA(variable, buf, bufsize);
if(!rc || rc == bufsize || rc > max) {
free(buf);
return NULL;
}
/* if rc < bufsize then rc is bytes written not including null */
if(rc < bufsize)
return buf;
/* else rc is bytes needed, try again */
}
#else
char *env = getenv(variable);
return (env && env[0])?strdup(env):NULL;
#endif
}
char *curl_getenv(const char *v)
{
return GetEnv(v);
}