xref: /third_party/curl/lib/getenv.c (revision 13498266)
113498266Sopenharmony_ci/***************************************************************************
213498266Sopenharmony_ci *                                  _   _ ____  _
313498266Sopenharmony_ci *  Project                     ___| | | |  _ \| |
413498266Sopenharmony_ci *                             / __| | | | |_) | |
513498266Sopenharmony_ci *                            | (__| |_| |  _ <| |___
613498266Sopenharmony_ci *                             \___|\___/|_| \_\_____|
713498266Sopenharmony_ci *
813498266Sopenharmony_ci * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
913498266Sopenharmony_ci *
1013498266Sopenharmony_ci * This software is licensed as described in the file COPYING, which
1113498266Sopenharmony_ci * you should have received as part of this distribution. The terms
1213498266Sopenharmony_ci * are also available at https://curl.se/docs/copyright.html.
1313498266Sopenharmony_ci *
1413498266Sopenharmony_ci * You may opt to use, copy, modify, merge, publish, distribute and/or sell
1513498266Sopenharmony_ci * copies of the Software, and permit persons to whom the Software is
1613498266Sopenharmony_ci * furnished to do so, under the terms of the COPYING file.
1713498266Sopenharmony_ci *
1813498266Sopenharmony_ci * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
1913498266Sopenharmony_ci * KIND, either express or implied.
2013498266Sopenharmony_ci *
2113498266Sopenharmony_ci * SPDX-License-Identifier: curl
2213498266Sopenharmony_ci *
2313498266Sopenharmony_ci ***************************************************************************/
2413498266Sopenharmony_ci
2513498266Sopenharmony_ci#include "curl_setup.h"
2613498266Sopenharmony_ci
2713498266Sopenharmony_ci#include <curl/curl.h>
2813498266Sopenharmony_ci#include "curl_memory.h"
2913498266Sopenharmony_ci
3013498266Sopenharmony_ci#include "memdebug.h"
3113498266Sopenharmony_ci
3213498266Sopenharmony_cistatic char *GetEnv(const char *variable)
3313498266Sopenharmony_ci{
3413498266Sopenharmony_ci#if defined(_WIN32_WCE) || defined(CURL_WINDOWS_APP) || \
3513498266Sopenharmony_ci  defined(__ORBIS__) || defined(__PROSPERO__) /* PlayStation 4 and 5 */
3613498266Sopenharmony_ci  (void)variable;
3713498266Sopenharmony_ci  return NULL;
3813498266Sopenharmony_ci#elif defined(_WIN32)
3913498266Sopenharmony_ci  /* This uses Windows API instead of C runtime getenv() to get the environment
4013498266Sopenharmony_ci     variable since some changes aren't always visible to the latter. #4774 */
4113498266Sopenharmony_ci  char *buf = NULL;
4213498266Sopenharmony_ci  char *tmp;
4313498266Sopenharmony_ci  DWORD bufsize;
4413498266Sopenharmony_ci  DWORD rc = 1;
4513498266Sopenharmony_ci  const DWORD max = 32768; /* max env var size from MSCRT source */
4613498266Sopenharmony_ci
4713498266Sopenharmony_ci  for(;;) {
4813498266Sopenharmony_ci    tmp = realloc(buf, rc);
4913498266Sopenharmony_ci    if(!tmp) {
5013498266Sopenharmony_ci      free(buf);
5113498266Sopenharmony_ci      return NULL;
5213498266Sopenharmony_ci    }
5313498266Sopenharmony_ci
5413498266Sopenharmony_ci    buf = tmp;
5513498266Sopenharmony_ci    bufsize = rc;
5613498266Sopenharmony_ci
5713498266Sopenharmony_ci    /* It's possible for rc to be 0 if the variable was found but empty.
5813498266Sopenharmony_ci       Since getenv doesn't make that distinction we ignore it as well. */
5913498266Sopenharmony_ci    rc = GetEnvironmentVariableA(variable, buf, bufsize);
6013498266Sopenharmony_ci    if(!rc || rc == bufsize || rc > max) {
6113498266Sopenharmony_ci      free(buf);
6213498266Sopenharmony_ci      return NULL;
6313498266Sopenharmony_ci    }
6413498266Sopenharmony_ci
6513498266Sopenharmony_ci    /* if rc < bufsize then rc is bytes written not including null */
6613498266Sopenharmony_ci    if(rc < bufsize)
6713498266Sopenharmony_ci      return buf;
6813498266Sopenharmony_ci
6913498266Sopenharmony_ci    /* else rc is bytes needed, try again */
7013498266Sopenharmony_ci  }
7113498266Sopenharmony_ci#else
7213498266Sopenharmony_ci  char *env = getenv(variable);
7313498266Sopenharmony_ci  return (env && env[0])?strdup(env):NULL;
7413498266Sopenharmony_ci#endif
7513498266Sopenharmony_ci}
7613498266Sopenharmony_ci
7713498266Sopenharmony_cichar *curl_getenv(const char *v)
7813498266Sopenharmony_ci{
7913498266Sopenharmony_ci  return GetEnv(v);
8013498266Sopenharmony_ci}
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