Add helper functions to copy strings into struct image_args.

Given a zeroed struct image_args with an allocated buf member,
exec_args_add_fname() must be called to install a file name (or NULL).
Then zero or more calls to exec_args_add_env() followed by zero or
more calls to exec_args_add_env(). exec_args_adjust_args() may be
called after args and/or env to allow an interpreter to be prepended to
the argument list.

To allow code reuse when adding arg and env variables, begin_envv
should be accessed with the accessor exec_args_get_begin_envv()
which handles the case when no environment entries have been added.

Use these functions to simplify exec_copyin_args() and
freebsd32_exec_copyin_args().

Reviewed by:	kib
Obtained from:	CheriBSD
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D15468

1 files changed, 3 insertions, 2 deletions

diff --git a/sys/compat/cloudabi64/cloudabi64_module.c b/sys/compat/cloudabi64/cloudabi64_module.c
index 9c71b87b08f4..fd0be086aac3 100644
--- a/sys/compat/cloudabi64/cloudabi64_module.c
+++ b/sys/compat/cloudabi64/cloudabi64_module.c
@@ -54,7 +54,7 @@ cloudabi64_copyout_strings(struct image_params *imgp)
 
 	/* Copy out program arguments. */
 	args = imgp->args;
-	len = args->begin_envv - args->begin_argv;
+	len = exec_args_get_begin_envv(args) - args->begin_argv;
 	begin = rounddown2(imgp->sysent->sv_usrstack - len, sizeof(register_t));
 	copyout(args->begin_argv, (void *)begin, len);
 	return ((register_t *)begin);
@@ -109,7 +109,8 @@ cloudabi64_fixup(register_t **stack_base, struct image_params *imgp)
 	 * exec_copyin_data_fds(). Undo this by reducing the length.
 	 */
 	args = (Elf64_Auxargs *)imgp->auxargs;
-	argdatalen = imgp->args->begin_envv - imgp->args->begin_argv;
+	argdatalen = exec_args_get_begin_envv(imgp->args) -
+	    imgp->args->begin_argv;
 	if (argdatalen > 0)
 		--argdatalen;