[RFC PATCH v1 11/13] exec: let close-range actions target the max fd
From: Li Chen <hidden>
Date: 2026-05-28 09:58:23
Also in:
linux-arch, linux-doc, linux-fsdevel, linux-kselftest, linux-mm, lkml
Subsystem:
documentation, filesystems (vfs and infrastructure), the rest · Maintainers:
Jonathan Corbet, Alexander Viro, Christian Brauner, Linus Torvalds
Allow CLOSE_RANGE actions to pass newfd == -1 to mean the largest possible fd. This gives userspace a compact way to request the common close_range(first, ~0U, flags) pattern even though the UAPI action uses signed fd fields so OPEN actions can still carry AT_FDCWD. Signed-off-by: Li Chen <redacted> --- Documentation/userspace-api/spawn_template.rst | 3 ++- fs/spawn_template.c | 10 +++++++--- 2 files changed, 9 insertions(+), 4 deletions(-)
diff --git a/Documentation/userspace-api/spawn_template.rst b/Documentation/userspace-api/spawn_template.rst
index afe215e51db6f..be66be20d4fde 100644
--- a/Documentation/userspace-api/spawn_template.rst
+++ b/Documentation/userspace-api/spawn_template.rst@@ -86,7 +86,8 @@ kind of setup that ``posix_spawn_file_actions_t`` commonly performs: Open a path using ``struct open_how`` and install it at ``newfd``. ``SPAWN_TEMPLATE_ACTION_CLOSE_RANGE`` - Apply ``close_range()`` to a child fd range. + Apply ``close_range()`` to a child fd range. Passing ``newfd == -1`` means + the range extends to the largest possible fd. ``SPAWN_TEMPLATE_ACTION_SIGMASK`` Set the child signal mask.
diff --git a/fs/spawn_template.c b/fs/spawn_template.c
index 6430a6645fb57..82b833bc9865a 100644
--- a/fs/spawn_template.c
+++ b/fs/spawn_template.c@@ -220,6 +220,8 @@ static int spawn_template_apply_sigdefault(const struct spawn_template_action *a static int spawn_template_apply_action(const struct spawn_template_action *action) { + unsigned int max_fd; + switch (action->type) { case SPAWN_TEMPLATE_ACTION_CLOSE: return close_fd(action->fd);
@@ -251,7 +253,8 @@ static int spawn_template_apply_action(const struct spawn_template_action *actio case SPAWN_TEMPLATE_ACTION_OPEN: return spawn_template_apply_open(action); case SPAWN_TEMPLATE_ACTION_CLOSE_RANGE: - return do_close_range(action->fd, action->newfd, action->flags); + max_fd = action->newfd == -1 ? ~0U : action->newfd; + return do_close_range(action->fd, max_fd, action->flags); case SPAWN_TEMPLATE_ACTION_SIGMASK: return spawn_template_apply_sigmask(action); case SPAWN_TEMPLATE_ACTION_SIGDEFAULT:
@@ -306,8 +309,9 @@ static int spawn_template_copy_actions(struct spawn_template_action **out_action return -EINVAL; break; case SPAWN_TEMPLATE_ACTION_CLOSE_RANGE: - if (actions[i].fd < 0 || actions[i].newfd < 0 || - actions[i].fd > actions[i].newfd || + if (actions[i].fd < 0 || actions[i].newfd < -1 || + (actions[i].newfd >= 0 && + actions[i].fd > actions[i].newfd) || (actions[i].flags & ~(CLOSE_RANGE_UNSHARE | CLOSE_RANGE_CLOEXEC)) || actions[i].arg)
--
2.52.0