The practical scenario that leads to this is porch(1) spawning some
utility and sending it a SIGSTOP as a debugging aide. The user then
attaches a debugger and walks through how some specific input is
processed, then detaches to allow the script to continue. When ptrace
is detached, the process resumes execution but the parent is never
notified and may be stuck in wait(2) for it to continue or terminate.
Other platforms seem to re-suspend the process after the debugger is
detached, but neither behavior seems unreasonable. Just notifying the
parent that the child has resumed is a relatively low-risk departure
from our current behavior and had apparently been considered in the
past, based on pre-existing comments.
Move p_flag and p_xsig handling into childproc_continued(), as just
sending the SIGCHLD here isn't really useful without P_CONTINUED set
and the other caller already sets these up as well.
Reviewed by: kib, markj
Differential Revision: https://reviews.freebsd.org/D50917
The usual way of handling process exit exit in capsicum(4) mode is
by using process descriptors (pdfork(2)) instead of the traditional
fork(2)/wait4(2) API. But most apps hadn't been converted this way,
and many cannot because the wait is hidden behind a library APIs that
revolve around PID numbers and not descriptors; GLib's
g_spawn_check_wait_status(3) is one example.
Thus, provide backwards compatibility by allowing the wait(2) family
of functions in Capsicum mode, except for child processes created by
pdfork(2).
Reviewed by: brooks, oshogbo
Sponsored by: Innovate UK
Differential Revision: https://reviews.freebsd.org/D44372
Remove core system call implementations and documentation to lib/libsys
and lib/libsys/<arch> from lib/libc/sys and lib/libc/<arch>/<sys>.
Update paths to allow libc to find them in their new home.
Reviewed by: kib, emaste, imp
Pull Request: https://github.com/freebsd/freebsd-src/pull/908
