Simplify the code to allocate stack for auxv, argv[], and environment vectors.

Remove auxarg_size as it was only used once right after a confusing
assignment in each of the variants of exec_copyout_strings().

Reviewed by:	emaste
MFC after:	1 month
Differential Revision:	https://reviews.freebsd.org/D15123

1 files changed, 11 insertions, 23 deletions

diff --git a/sys/kern/kern_exec.c b/sys/kern/kern_exec.c
index c55851f5b420..29eae3967a68 100644
--- a/sys/kern/kern_exec.c
+++ b/sys/kern/kern_exec.c
@@ -1537,35 +1537,23 @@ exec_copyout_strings(struct image_params *imgp)
 	destp -= ARG_MAX - imgp->args->stringspace;
 	destp = rounddown2(destp, sizeof(void *));
 
-	/*
-	 * If we have a valid auxargs ptr, prepare some room
-	 * on the stack.
-	 */
+	vectp = (char **)destp;
 	if (imgp->auxargs) {
 		/*
-		 * 'AT_COUNT*2' is size for the ELF Auxargs data. This is for
-		 * lower compatibility.
-		 */
-		imgp->auxarg_size = (imgp->auxarg_size) ? imgp->auxarg_size :
-		    (AT_COUNT * 2);
-		/*
-		 * The '+ 2' is for the null pointers at the end of each of
-		 * the arg and env vector sets,and imgp->auxarg_size is room
-		 * for argument of Runtime loader.
-		 */
-		vectp = (char **)(destp - (imgp->args->argc +
-		    imgp->args->envc + 2 + imgp->auxarg_size)
-		    * sizeof(char *));
-	} else {
-		/*
-		 * The '+ 2' is for the null pointers at the end of each of
-		 * the arg and env vector sets
+		 * Allocate room on the stack for the ELF auxargs
+		 * array.  It has up to AT_COUNT entries.
 		 */
-		vectp = (char **)(destp - (imgp->args->argc + imgp->args->envc
-		    + 2) * sizeof(char *));
+		vectp -= howmany(AT_COUNT * sizeof(Elf_Auxinfo),
+		    sizeof(*vectp));
 	}
 
 	/*
+	 * Allocate room for the argv[] and env vectors including the
+	 * terminating NULL pointers.
+	 */
+	vectp -= imgp->args->argc + 1 + imgp->args->envc + 1;
+
+	/*
 	 * vectp also becomes our initial stack base
 	 */
 	stack_base = (register_t *)vectp;