(child_setup): Omit duplicates from new env array.

diff --git a/src/callproc.c b/src/callproc.c
index 7fd218b584d7ebb8ec459cc7c5453f65c13333c7..df5405a07fc82eba4f73bc9733b21276c9ad1272 100644 (file)
--- a/src/callproc.c
+++ b/src/callproc.c
@@ -463,15 +463,39 @@ child_setup (in, out, err, new_argv, set_pgrp, current_dir)
         tem = XCONS (tem)->cdr)
       new_length++;
 
-    /* new_length + 1 to include terminating 0 */
+    /* new_length + 1 to include terminating 0.  */
     env = new_env = (char **) alloca ((new_length + 1) * sizeof (char *));
 
-    /* Copy the Vprocess_alist strings into new_env.  */
+    /* Copy the Vprocess_environment strings into new_env.  */
     for (tem = Vprocess_environment;
         (XTYPE (tem) == Lisp_Cons
          && XTYPE (XCONS (tem)->car) == Lisp_String);
         tem = XCONS (tem)->cdr)
-      *new_env++ = (char *) XSTRING (XCONS (tem)->car)->data;
+      {
+       char **ep = env;
+       char *string = (char *) XSTRING (XCONS (tem)->car)->data;
+       /* See if this string duplicates any string already in the env.
+          If so, don't put it in.
+          When an env var has multiple definitions,
+          we keep the definition that comes first in process-environment.  */
+       for (; ep != new_env; ep++)
+         {
+           char *p = *ep, *q = string;
+           while (1)
+             {
+               if (*q == 0)
+                 /* The string is malformed; might as well drop it.  */
+                 goto duplicate;
+               if (*q != *p)
+                 break;
+               if (*q == '=')
+                 goto duplicate;
+               p++, q++;
+             }
+         }
+       *new_env++ = string;
+      duplicate: ;
+      }
     *new_env = 0;
   }