X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/a4837536e2ef918dacf687c134e690cbbe693487..89bd9d36859503e25b767f97395870190f272bc1:/lib/putenv.c

diff --git a/lib/putenv.c b/lib/putenv.c
index 5f0fedaf9c..ed666afc3b 100644
--- a/lib/putenv.c
+++ b/lib/putenv.c
@@ -34,6 +34,11 @@
 #include <string.h>
 #include <unistd.h>
 
+#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+# define WIN32_LEAN_AND_MEAN
+# include <windows.h>
+#endif
+
 #if _LIBC
 # if HAVE_GNU_LD
 #  define environ __environ
@@ -67,6 +72,21 @@ _unsetenv (const char *name)
 
   len = strlen (name);
 
+#if HAVE__PUTENV
+  {
+    int putenv_result, putenv_errno;
+    char *name_ = malloc (len + 2);
+    memcpy (name_, name, len);
+    name_[len] = '=';
+    name_[len + 1] = 0;
+    putenv_result = _putenv (name_);
+    putenv_errno = errno;
+    free (name_);
+    __set_errno (putenv_errno);
+    return putenv_result;
+  }
+#else
+
   LOCK;
 
   ep = environ;
@@ -87,6 +107,7 @@ _unsetenv (const char *name)
   UNLOCK;
 
   return 0;
+#endif
 }
 
 
@@ -95,9 +116,8 @@ _unsetenv (const char *name)
 int
 putenv (char *string)
 {
-  const char *const name_end = strchr (string, '=');
-  register size_t size;
-  register char **ep;
+  const char *name_end = strchr (string, '=');
+  char **ep;
 
   if (name_end == NULL)
     {
@@ -105,30 +125,68 @@ putenv (char *string)
       return _unsetenv (string);
     }
 
-  size = 0;
-  for (ep = environ; *ep != NULL; ++ep)
-    if (!strncmp (*ep, string, name_end - string) &&
-        (*ep)[name_end - string] == '=')
+#if HAVE__PUTENV
+      /* Rely on _putenv to allocate the new environment.  If other
+         parts of the application use _putenv, the !HAVE__PUTENV code
+         would fight over who owns the environ vector, causing a crash.  */
+      if (name_end[1])
+        return _putenv (string);
+      else
+        {
+          /* _putenv ("NAME=") unsets NAME, so invoke _putenv ("NAME= ")
+             to allocate the environ vector and then replace the new
+             entry with "NAME=".  */
+          int putenv_result, putenv_errno;
+          char *name_x = malloc (name_end - string + sizeof "= ");
+          if (!name_x)
+            return -1;
+          memcpy (name_x, string, name_end - string + 1);
+          name_x[name_end - string + 1] = ' ';
+          name_x[name_end - string + 2] = 0;
+          putenv_result = _putenv (name_x);
+          putenv_errno = errno;
+          for (ep = environ; *ep; ep++)
+            if (strcmp (*ep, name_x) == 0)
+              {
+                *ep = string;
+                break;
+              }
+# if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+          if (putenv_result == 0)
+            {
+              /* _putenv propagated "NAME= " into the subprocess environment;
+                 fix that by calling SetEnvironmentVariable directly.  */
+              name_x[name_end - string] = 0;
+              putenv_result = SetEnvironmentVariable (name_x, "") ? 0 : -1;
+              putenv_errno = ENOMEM; /* ENOMEM is the only way to fail.  */
+            }
+# endif
+          free (name_x);
+          __set_errno (putenv_errno);
+          return putenv_result;
+        }
+#else
+  for (ep = environ; *ep; ep++)
+    if (strncmp (*ep, string, name_end - string) == 0
+        && (*ep)[name_end - string] == '=')
       break;
-    else
-      ++size;
 
-  if (*ep == NULL)
+  if (*ep)
+    *ep = string;
+  else
     {
       static char **last_environ = NULL;
-      char **new_environ = (char **) malloc ((size + 2) * sizeof (char *));
-      if (new_environ == NULL)
+      size_t size = ep - environ;
+      char **new_environ = malloc ((size + 2) * sizeof *new_environ);
+      if (! new_environ)
         return -1;
-      (void) memcpy ((void *) new_environ, (void *) environ,
-                     size * sizeof (char *));
-      new_environ[size] = (char *) string;
-      new_environ[size + 1] = NULL;
+      new_environ[0] = string;
+      memcpy (new_environ + 1, environ, (size + 1) * sizeof *new_environ);
       free (last_environ);
       last_environ = new_environ;
       environ = new_environ;
     }
-  else
-    *ep = string;
+#endif
 
   return 0;
 }