Merge branch 'upstream-curl' into update-curl

* upstream-curl:
  curl 2020-03-04 (b8d13668)

1 files changed, 35 insertions, 12 deletions

diff --git a/Utilities/cmcurl/lib/getenv.c b/Utilities/cmcurl/lib/getenv.c
index 89d181d..9385b8f 100644
--- a/Utilities/cmcurl/lib/getenv.c
+++ b/Utilities/cmcurl/lib/getenv.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2012, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * 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
@@ -27,25 +27,48 @@
 
 #include "memdebug.h"
 
-static
-char *GetEnv(const char *variable)
+static char *GetEnv(const char *variable)
 {
 #if defined(_WIN32_WCE) || defined(CURL_WINDOWS_APP)
   (void)variable;
   return NULL;
-#else
-#ifdef WIN32
-  char env[MAX_PATH]; /* MAX_PATH is from windef.h */
-  char *temp = getenv(variable);
-  env[0] = '\0';
-  if(temp != NULL)
-    ExpandEnvironmentStringsA(temp, env, sizeof(env));
-  return (env[0] != '\0')?strdup(env):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
-#endif
 }
 
 char *curl_getenv(const char *v)