[PATCH v10 00/15] Making BusyBox self-contained

[Nadav Tasher]

The following patchset aims to implement the following features in
the simplest way possible:
1. Introduce a simple way to control exec calls by all applets.
2. Create a unified interface from which applets can execute
other applets using the no-exec feature (reducing duplicate code).
3. Allow blocking exec calls altogether using the exec proxy functions.
4. Adapt all applets to run with these modifications.

This revision introduces the required modifications to the hush applet.

These changes allow the creation of a self-contained system, powered
by BusyBox.

By bundling BusyBox into libbusybox.a (using a separate patch), this
provides the foundation for embedding BusyBox in other programs,
acting as a complete shell interpreter.

Previous versions of this patchset were partially reviewed by:
- Csókás Bence
- Ron Yorston
- David Leonard
- Kang-Che Sung

Nadav Tasher (15):
  libbb: mask xvfork to xfork on MMU targets
  libbb: implement clone_string_array
  libbb: implement close_cloexec_fds
  libbb: implement reset_all_signals
  libbb: implement bb_execXX function family to handle applet executions
  libbb: make spawn and spawn_and_wait use bb_execvp
  libbb: implement bb_system using spawn_and_wait
  applets: change system() calls to bb_system()
  ash: use bb_execve to execute commands and applets in tryexec
  hush: use bb_execvp to execute commands and applets in execvp_or_die
  tar: replace execlp call with bb_execvp, disable xz compression
    support when FEATURE_PREFER_APPLETS is enabled
  applets: use bb_execXX functions instead of direct exec calls
  httpd: replace execv call with bb_execv and disable FEATURE_HTTPD_CGI
    when FEATURE_FORCE_APPLETS is enabled
  libbb: allow forcing all applets to behave as NOEXEC applets
  libbb: implement re_exec using bb_execv

 Config.in                                     |  22 ++++
 archival/dpkg.c                               |   2 +-
 archival/libarchive/data_extract_to_command.c |   9 +-
 archival/libarchive/open_transformer.c        |   3 +-
 archival/tar.c                                |  28 ++++-
 console-tools/openvt.c                        |   2 +-
 console-tools/reset.c                         |   2 +-
 coreutils/chroot.c                            |   2 +-
 coreutils/env.c                               |   2 +-
 coreutils/nice.c                              |   2 +-
 coreutils/nohup.c                             |   2 +-
 coreutils/timeout.c                           |   2 +-
 debianutils/start_stop_daemon.c               |   2 +-
 docs/nofork_noexec.txt                        |  13 +-
 editors/awk.c                                 |   2 +-
 editors/vi.c                                  |   2 +-
 include/libbb.h                               |  56 ++++++---
 init/bootchartd.c                             |  21 +++-
 init/halt.c                                   |   9 +-
 init/init.c                                   |   4 +-
 libbb/Kbuild.src                              |   1 +
 libbb/clone_string_array.c                    |  29 +++++
 libbb/executable.c                            | 111 ++++++++++++++++--
 libbb/run_shell.c                             |   4 +-
 libbb/signals.c                               |  26 ++++
 libbb/vfork_daemon_rexec.c                    |  72 +++++++++---
 libbb/xfuncs.c                                |  10 ++
 loginutils/adduser.c                          |   7 +-
 loginutils/getty.c                            |  19 ++-
 mailutils/mail.c                              |   2 +-
 mailutils/reformime.c                         |   2 +-
 miscutils/conspy.c                            |  11 +-
 miscutils/crond.c                             |  38 +++++-
 miscutils/crontab.c                           |  13 +-
 miscutils/man.c                               |   2 +-
 miscutils/time.c                              |   2 +-
 networking/ftpd.c                             |   3 +-
 networking/httpd.c                            |   8 +-
 networking/ifupdown.c                         |  17 ++-
 networking/inetd.c                            |   6 +-
 networking/nc.c                               |   3 +-
 networking/nc_bloaty.c                        |   2 +-
 networking/slattach.c                         |   2 +-
 networking/tcpudp.c                           |   2 +-
 networking/telnetd.c                          |   2 +-
 networking/wget.c                             |   5 +-
 printutils/lpd.c                              |   2 +-
 procps/watch.c                                |   2 +-
 runit/chpst.c                                 |   2 +-
 runit/runsv.c                                 |   9 +-
 runit/runsvdir.c                              |  13 +-
 runit/svlogd.c                                |  15 ++-
 selinux/runcon.c                              |   2 +-
 shell/ash.c                                   |  72 ++++--------
 shell/cttyhack.c                              |   2 +-
 shell/hush.c                                  |  44 +------
 util-linux/chrt.c                             |   2 +-
 util-linux/ionice.c                           |   2 +-
 util-linux/mdev.c                             |   2 +-
 util-linux/script.c                           |  18 ++-
 util-linux/setarch.c                          |   2 +-
 util-linux/setpriv.c                          |   2 +-
 util-linux/setsid.c                           |   2 +-
 util-linux/switch_root.c                      |   2 +-
 util-linux/taskset.c                          |   2 +-
 65 files changed, 555 insertions(+), 228 deletions(-)
 create mode 100644 libbb/clone_string_array.c

-- 
2.34.1