Since glibc 2.26, posix_spawn (2) function accepts the
POSIX_SPAWN_SETSID flag. This flag has been accepted by POSIX and
should be added to the next major revision. The current support
can be enabled with _GNU_SOURCE.
Upstream commit in glibc.git:
daeb1fa2e1 [BZ 21340] add support for POSIX_SPAWN_SETSID
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Signed-off-by: Olivier Gayot <olivier.gayot@sigexec.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
The implementation of the fork() step in posix_spawn(2) relies on
either fork(2), vfork(2) or clone(2) depending on the version of
the glibc and the arguments passed to posix_spawn(2).
It is sometimes ambiguous whether, when we are mentioning
"fork(2)", we are referring to the fork() step or the actual
fork(2) syscall.
This patch hopefully avoids the ambiguity by replacing confusing
occurrences by "the xxx() step" where appropriate.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Signed-off-by: Olivier Gayot <olivier.gayot@sigexec.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Added a few lines about POSIX_SPAWN_USEVFORK so that it appears
clearly that since glibc 2.24, the flag has no effect.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Signed-off-by: Olivier Gayot <olivier.gayot@sigexec.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Since glibc 2.24, the use of posix_spawn (2) makes an
unconditional call to clone(CLONE_VM | CLONE_VFORK ...) rather
than relying on fork (2) or vfork (2).
As a consequence, the statements regarding the use of the flag
POSIX_SPAWN_USEVFORK and how the function decides whether it
should use fork (2) or vfork (2) are obsolete since glibc 2.24.
This patch makes a distinction in the manual page between glibc
2.24 and older versions.
Upstream commit in glibc.git:
9ff72da471 posix: New Linux posix_spawn{p} implementation
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Signed-off-by: Olivier Gayot <olivier.gayot@sigexec.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Taken from Linux v5.3-rc2. Add a reference to the header file to
save the future reader some time figuring out whether more entries
exist.
Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
In Linux 4.4, the allowed BPF helper functions that could
be called was governed by a check in sk_filter_func_proto().
Nowadays (Linux 5.6), it is I think governed by the check in
sk_filter_func_proto().
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This notes that the kernel now allows calls to bpf() without CAP_SYS_ADMIN
under some circumstances.
Signed-off-by: Richard Palethorpe <rpalethorpe@suse.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
The cgroup.sane_behavior file returns the hard-coded value "0" and
is kept for legacy purposes. Mention this in the man-page.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Michael Kerrisk