[PATCH v2 2/4] man/man5/tunables.conf: Document system-wide tunables config

---
 man/man5/tunables.conf.5 | 116 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 116 insertions(+)
 create mode 100644 man/man5/tunables.conf.5

diff --git a/man/man5/tunables.conf.5 b/man/man5/tunables.conf.5
new file mode 100644
index 000000000..e2b31e351
--- /dev/null
+++ b/man/man5/tunables.conf.5
@@ -0,0 +1,116 @@
+.TH tunables.conf 5 (date) "Linux man-pages (unreleased)"
+.SH NAME
+tunables.conf \- tunables configuration file
+.SH SYNOPSIS
+.nf
+.B /etc/tunables.conf
+.fi
+.SH DESCRIPTION
+Each line in the file
+.I /etc/tunables.conf
+specifies a tunable,
+which is a name and value separated by an equals sign.
+.P
+For a list of valid tunables,
+please consult the glibc manual.
+.P
+The syntax allows lines to start with the word
+.I include
+followed by a path wildcard,
+and will include any files matching that wildcard.
+The wildcard is a path specification in the
+.BR \%glob (7)
+format.
+Files matching that wildcard will be processed
+as if their contents were included in the main config file.
+.P
+The file is parsed by
+.BR \%ldconfig (8)
+and the results stored in
+.IR /etc/ld.so.cache .
+The resulting data is read when a new process starts.
+.P
+Each line may include zero or more words or symbols at the beginning,
+which affect how each tunable affects each processes:
+.TP
+.B overridable
+.TQ
+.B +
+Allow the tunable to be overridden by the
+.B GLIBC_TUNABLES
+environment variable when the process runs
+(this is the default).
+.TP
+.B nonoverridable
+.TQ
+.B \-
+Do not allow the tunable to be overridden by the environment variable.
+.TP
+.B onlysecure
+.TQ
+.B @
+The tunable only applies to
+.B AT_SECURE
+processes,
+such as a set-user-ID process,
+or one with elevated capabilities.
+.TP
+.B nonsecure
+.TQ
+.B $
+The tunable only applies to
+.RB non- AT_SECURE
+processes (this is the default).
+.TP
+.B anysecure
+.TQ
+.B *
+The tunable only applies to both
+.B AT_SECURE
+and
+.RB non- AT_SECURE
+processes.
+.P
+The file may also contain
+.IR filters ,
+which limit the tunables following it,
+up to the end of the file
+(or end of the included file,
+or start of a new included file)
+or a line with only
+.B []
+on it.
+The syntax is:
+.IP
+.in +4n
+.EX
+.RI [ filter : pattern ]
+.EE
+.in
+.TP
+.B proc
+The
+.I proc
+filter limits the following tunables to processes
+whose name matches the pattern.
+The pattern may be an absolute path
+or just the base name.
+.P
+Example config file:
+.IP
+.in +4n
+.EX
+glibc.malloc.arenas_max=5
+onlysecure glibc.malloc.arenas_max=1
+\-glibc.pthread.rseq=1
+[proc:/bin/bad.program]
+\-glibc.pthread.rseq=0
+[proc:some.program]
+\-glibc.malloc.mmap_threshold=65536
+.EE
+.in
+.SH FILES
+.I /etc/ld.so.conf
+.SH SEE ALSO
+.BR ld.so (8),
+.BR ldconfig (8)
-- 
2.47.3