r22988: fixed 2 bugs in our unsetenv() replacement code

 1) you must not free the memory, as it is possible the memory did not
 come from malloc (try it under valgrind to test)

 2) the old code didn't cope with duplicate environment variables

I hope this will fix some of the build farm errors on irix, and maybe solaris
(This used to be commit ec6900171d066e927f004b621fb39cc7b8dcfd90)

1 files changed, 15 insertions, 11 deletions

diff --git a/source4/lib/replace/replace.c b/source4/lib/replace/replace.c
index db299130e5..87e73d001c 100644
--- a/source4/lib/replace/replace.c
+++ b/source4/lib/replace/replace.c
@@ -568,20 +568,24 @@ int rep_unsetenv(const char *name)
 {
 	extern char **environ;
 	size_t len = strlen(name);
-	size_t i; 
-	int found = 0;
+	size_t i, count;
 
-	for (i=0; (environ && environ[i]); i++) {
-		if (found) {
-			environ[i-1] = environ[i];
-			continue;
-		}
+	if (environ == NULL || getenv(name) == NULL) {
+		return 0;
+	}
 
+	for (i=0;environ[i];i++) /* noop */ ;
+
+	count=i;
+	
+	for (i=0;i<count;) {
 		if (strncmp(environ[i], name, len) == 0 && environ[i][len] == '=') {
-			free(environ[i]);
-			environ[i] = NULL;
-			found = 1;
-			continue;
+			/* note: we do _not_ free the old variable here. It is unsafe to 
+			   do so, as the pointer may not have come from malloc */
+			memmove(&environ[i], &environ[i+1], (count-i)*sizeof(char *));
+			count--;
+		} else {
+			i++;
 		}
 	}