[PATCH v2 0/4] Tunables-related updates

[PATCH v2 0/4] Tunables-related updates

[DJ Delorie]

DJ Delorie (4):
  man/man5/ld.so.conf.5: document include syntax
  man/man5/tunables.conf: Document system-wide tunables config
  man/man8/ld.so.8: Note that ld.so.cache includes tunables
  man/man8/ldconfig.8: Add tunables options

 man/man5/ld.so.conf.5    |  28 ++++++++++
 man/man5/tunables.conf.5 | 116 +++++++++++++++++++++++++++++++++++++++
 man/man8/ld.so.8         |   3 +-
 man/man8/ldconfig.8      |  25 ++++++++-
 4 files changed, 168 insertions(+), 4 deletions(-)
 create mode 100644 man/man5/tunables.conf.5

-- 
2.47.3

[PATCH v2 1/4] man/man5/ld.so.conf.5: document include syntax

[DJ Delorie]

---
 man/man5/ld.so.conf.5 | 28 ++++++++++++++++++++++++++++
 man/man8/ldconfig.8   |  2 --
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/man/man5/ld.so.conf.5 b/man/man5/ld.so.conf.5
index 481cf9152..25f9adf90 100644
--- a/man/man5/ld.so.conf.5
+++ b/man/man5/ld.so.conf.5
@@ -9,6 +9,34 @@ .SH DESCRIPTION
 This file contains a list of directories,
 one per line,
 in which to search for libraries.
+.P
+The file
+(and any other files included by it)
+is parsed by
+.B \%ldconfig
+and the results stored in
+.IR /etc/ld.so.cache .
+.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
+Example config file:
+.IP
+.in +4n
+.EX
+/lib
+/usr/lib
+/usr/local/lib
+include /etc/ld.so.conf.d/*.conf
+.EE
+.in
 .SH FILES
 .I /etc/ld.so.conf
 .SH SEE ALSO
diff --git a/man/man8/ldconfig.8 b/man/man8/ldconfig.8
index 9ac146b44..cb7d62ccc 100644
--- a/man/man8/ldconfig.8
+++ b/man/man8/ldconfig.8
@@ -178,8 +178,6 @@ .SH OPTIONS
 is also specified,
 the cache is still rebuilt.
 .SH FILES
-.\" FIXME Since glibc-2.3.4, "include" directives are supported in ld.so.conf
-.\"
 .\" FIXME Since glibc-2.4, "hwcap" directives are supported in ld.so.conf
 .PD 0
 .TP
-- 
2.47.3

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

[DJ Delorie]

---
 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

[PATCH v2 3/4] man/man8/ld.so.8: Note that ld.so.cache includes tunables

[DJ Delorie]

---
 man/man8/ld.so.8 | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/man/man8/ld.so.8 b/man/man8/ld.so.8
index 5f3c22ef2..8916f2443 100644
--- a/man/man8/ld.so.8
+++ b/man/man8/ld.so.8
@@ -792,7 +792,8 @@ .SH FILES
 .TP
 .I /etc/ld.so.cache
 File containing a compiled list of directories in which to search for
-shared objects and an ordered list of candidate shared objects.
+shared objects and an ordered list of candidate shared objects,
+and any tunables to be applied.
 See
 .BR ldconfig (8).
 .TP
-- 
2.47.3

[PATCH v2 4/4] man/man8/ldconfig.8: Add tunables options

[DJ Delorie]

---
 man/man8/ldconfig.8 | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/man/man8/ldconfig.8 b/man/man8/ldconfig.8
index cb7d62ccc..e575fdec6 100644
--- a/man/man8/ldconfig.8
+++ b/man/man8/ldconfig.8
@@ -17,6 +17,8 @@ .SH SYNOPSIS
 .IR conf ]
 .RB [ \-r\~\c
 .IR root ]
+.RB [ \-t\~\c
+.IR tunconf ]
 .IR directory \~.\|.\|.
 .YS
 .SY /sbin/ldconfig
@@ -85,6 +87,13 @@ .SH DESCRIPTION
 .P
 Failure to follow this pattern may result in compatibility issues
 after an upgrade.
+.P
+If the file
+.I /etc/tunables.conf
+exists,
+it contains tunables to be applied to all processes.
+These tunables are stored
+in the cache and applied to every process at its startup.
 .SH OPTIONS
 .TP
 .BI \-\-format= fmt
@@ -157,6 +166,12 @@ .SH OPTIONS
 .I root
 as the root directory.
 .TP
+.BI \-t\~ tunconf
+Use
+.I tunconf
+instead of
+.IR /etc/tunables.conf .
+.TP
 .B \-\-verbose
 .TQ
 .B \-v
@@ -188,11 +203,17 @@ .SH FILES
 See
 .BR ld.so.conf (5).
 .TP
+.I /etc/tunables.conf
+See
+.BR tunables.conf (5).
+.TP
 .I /etc/ld.so.cache
 contains an ordered list of libraries found in the directories
 specified in
 .IR /etc/ld.so.conf ,
-as well as those found in the trusted directories.
+as well as those found in the trusted directories,
+and any tunables listed in
+.IR /etc/tunables.conf .
 .PD
 .SH SEE ALSO
 .BR ldd (1),
-- 
2.47.3