random.4, gai.conf.5, slabinfo.5, cgroup_namespaces.7, feature_test_macros.7, keyrings.7, locale.7, man-pages.7, sock_diag.7: ffix

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This commit is contained in:
Michael Kerrisk 2017-08-19 10:56:06 +02:00
parent 010c75a2bb
commit 9c40f2b9ba
9 changed files with 73 additions and 67 deletions

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@ -153,11 +153,13 @@ If your system does not have
\fI/dev/random\fP and \fI/dev/urandom\fP created already, they
can be created with the following commands:
.PP
.nf
mknod \-m 666 /dev/random c 1 8
mknod \-m 666 /dev/urandom c 1 9
chown root:root /dev/random /dev/urandom
.fi
.in +4n
.EX
mknod \-m 666 /dev/random c 1 8
mknod \-m 666 /dev/urandom c 1 9
chown root:root /dev/random /dev/urandom
.EE
.in
.PP
When a Linux system starts up without much operator interaction,
the entropy pool may be in a fairly predictable state.
@ -168,38 +170,42 @@ entropy pool information across shut-downs and start-ups.
To do this, add the lines to an appropriate script
which is run during the Linux system start-up sequence:
.PP
.nf
echo "Initializing random number generator..."
random_seed=/var/run/random-seed
# Carry a random seed from start-up to start-up
# Load and then save the whole entropy pool
if [ \-f $random_seed ]; then
cat $random_seed >/dev/urandom
else
touch $random_seed
fi
chmod 600 $random_seed
poolfile=/proc/sys/kernel/random/poolsize
[ \-r $poolfile ] && bits=$(cat $poolfile) || bits=4096
bytes=$(expr $bits / 8)
dd if=/dev/urandom of=$random_seed count=1 bs=$bytes
.fi
.in +4n
.EX
echo "Initializing random number generator..."
random_seed=/var/run/random-seed
# Carry a random seed from start-up to start-up
# Load and then save the whole entropy pool
if [ \-f $random_seed ]; then
cat $random_seed >/dev/urandom
else
touch $random_seed
fi
chmod 600 $random_seed
poolfile=/proc/sys/kernel/random/poolsize
[ \-r $poolfile ] && bits=$(cat $poolfile) || bits=4096
bytes=$(expr $bits / 8)
dd if=/dev/urandom of=$random_seed count=1 bs=$bytes
.EE
.in
.PP
Also, add the following lines in an appropriate script which is
run during the Linux system shutdown:
.PP
.nf
# Carry a random seed from shut-down to start-up
# Save the whole entropy pool
echo "Saving random seed..."
random_seed=/var/run/random-seed
touch $random_seed
chmod 600 $random_seed
poolfile=/proc/sys/kernel/random/poolsize
[ \-r $poolfile ] && bits=$(cat $poolfile) || bits=4096
bytes=$(expr $bits / 8)
dd if=/dev/urandom of=$random_seed count=1 bs=$bytes
.fi
.in +4n
.EX
# Carry a random seed from shut-down to start-up
# Save the whole entropy pool
echo "Saving random seed..."
random_seed=/var/run/random-seed
touch $random_seed
chmod 600 $random_seed
poolfile=/proc/sys/kernel/random/poolsize
[ \-r $poolfile ] && bits=$(cat $poolfile) || bits=4096
bytes=$(expr $bits / 8)
dd if=/dev/urandom of=$random_seed count=1 bs=$bytes
.EE
.in
.PP
In the above examples, we assume Linux 2.6.0 or later, where
.IR /proc/sys/kernel/random/poolsize

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@ -80,7 +80,8 @@ file is supported by glibc since version 2.5.
The default table according to RFC\ 3484 would be specified with the
following configuration file:
.PP
.nf
.in +4n
.EX
label ::1/128 0
label ::/0 1
label 2002::/16 2
@ -91,7 +92,8 @@ precedence ::/0 40
precedence 2002::/16 30
precedence ::/96 20
precedence ::ffff:0:0/96 10
.fi
.EE
.in
.\" .SH AUTHOR
.\" Ulrich Drepper <drepper@redhat.com>
.\"

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@ -39,7 +39,7 @@ The following (edited) output shows an example of the
contents of this file:
.PP
.in 0
.nf
.EX
$ \fBsudo cat /proc/slabinfo\fP
slabinfo - version: 2.1
# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab> ...
@ -95,7 +95,11 @@ the tunables for a particular cache can be set by writing
lines of the following form to
.IR /proc/slabinfo :
.PP
# \fBecho 'name limit batchcount sharedfactor' > /proc/slabinfo\fP
.in +4n
.EX
# \fBecho 'name limit batchcount sharedfactor' > /proc/slabinfo\fP
.EE
.in
.PP
Here,
.I name

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@ -88,13 +88,11 @@ Next, we use
.BR unshare (1)
to create a process running a new shell in new cgroup and mount namespaces:
.PP
.nf
.EX
.in +4n
# \fBunshare \-Cm bash\fP
.in
.EE
.fi
.PP
We then inspect the
.IR /proc/[pid]/cgroup
@ -105,7 +103,6 @@ command, a process that is in the original cgroup namespace
with PID 1), and a process in a sibling cgroup
.RI ( sub2 ):
.PP
.nf
.EX
.in +4n
$ \fBcat /proc/self/cgroup | grep freezer\fP
@ -116,7 +113,6 @@ $ \fBcat /proc/20124/cgroup | grep freezer\fP
7:freezer:/../sub2
.in
.EE
.fi
.PP
From the output of the first command,
we see that the freezer cgroup membership of the new shell
@ -136,14 +132,12 @@ However, when we look in
.IR /proc/self/mountinfo
we see the following anomaly:
.PP
.nf
.EX
.in +4n
# \fBcat /proc/self/mountinfo | grep freezer\fP
155 145 0:32 /.. /sys/fs/cgroup/freezer ...
.in
.EE
.fi
.PP
The fourth field of this line
.RI ( /.. )
@ -159,7 +153,6 @@ filesystem corresponding to our initial shell process's cgroup namespace
We need to remount the freezer cgroup filesystem
inside this cgroup namespace, after which we see the expected results:
.PP
.nf
.EX
.in +4n
# \fBmount \-\-make\-rslave /\fP # Don't propagate mount events
@ -170,7 +163,6 @@ inside this cgroup namespace, after which we see the expected results:
155 145 0:32 / /sys/fs/cgroup/freezer rw,relatime ...
.in
.EE
.fi
.PP
Use of cgroup namespaces requires a kernel that is configured with the
.B CONFIG_CGROUPS

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@ -85,13 +85,13 @@ from
.I either
of the following macro
definitions must be made before including any header files:
.RS
.nf
.PP
.in +4n
.EX
#define _BSD_SOURCE
#define _XOPEN_SOURCE /* or any value < 500 */
.fi
.RE
.EE
.in
.PP
Alternatively, equivalent definitions can be included in the
compilation command:

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@ -540,8 +540,8 @@ An example of the data that one might see in this file
(with the columns numbered for easy reference below)
is the following:
.IP
.nf
.in 0n
.EX
(1) (2) (3)(4) (5) (6) (7) (8) (9)
009a2028 I--Q--- 1 perm 3f010000 1000 1000 user krb_ccache:primary: 12
1806c4ba I--Q--- 1 perm 3f010000 1000 1000 keyring _pid: 2

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@ -260,9 +260,9 @@ Values about local numeric formatting is made available in a
returned by the
.BR localeconv (3)
function, which has the following declaration:
.in +2n
.nf
.PP
.in +4n
.EX
struct lconv {
/* Numeric (nonmonetary) information */

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@ -174,9 +174,9 @@ Most manual pages should include at least the
sections.
Arrange a new manual page so that sections
are placed in the order shown in the list.
.in +0.5i
.PP
.in +4n
.nf
\fBNAME\fP
\fBSYNOPSIS\fP
CONFIGURATION [Normally only in Section 4]
@ -203,7 +203,7 @@ EXAMPLE
.\" AUTHORS sections are discouraged
.\" AUTHORS [Discouraged]
\fBSEE ALSO\fP
.EE
.fi
.in
.PP
.IR "Where a traditional heading would apply" ", " "please use it" ;
@ -519,11 +519,11 @@ For example, in the
man page, references to the subject of the page would be written as:
.BR fcntl ().
The preferred way to write this in the source file is:
.nf
.PP
.EX
.BR fcntl ()
.fi
.EE
.PP
(Using this format, rather than the use of "\\fB...\\fP()"
makes it easier to write tools that parse man page source files.)
.\"
@ -588,11 +588,11 @@ formatted in Roman (normal) font, without any
separating spaces (e.g.,
.BR intro (2)).
The preferred way to write this in the source file is:
.nf
.PP
.EX
.BR intro (2)
.fi
.EE
.PP
(Including the section number in cross references lets tools like
.BR man2html (1)
create properly hyperlinked pages.)
@ -628,7 +628,9 @@ except where English usage (e.g., proper nouns) or programming
language requirements (e.g., identifier names) dictate otherwise.
For example:
.PP
.EX
.SS Unicode under Linux
.EE
.\"
.SS Indentation of structure definitions, shell session logs, and so on
When structure definitions, shell session logs, and so on are included

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@ -641,7 +641,7 @@ were introduced in Linux 3.6.
The following example program prints inode number, peer's inode number,
and name of all UNIX domain sockets in the current namespace.
.PP
.nf
.EX
#include <errno.h>
#include <stdio.h>
#include <string.h>
@ -834,7 +834,7 @@ main(void)
close(fd);
return ret;
}
.fi
.EE
.SH SEE ALSO
.BR netlink (3),
.BR rtnetlink (3),