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-rw-r--r--docs/man/pkcheck.xml29
1 files changed, 20 insertions, 9 deletions
diff --git a/docs/man/pkcheck.xml b/docs/man/pkcheck.xml
index fc54054..c856ca4 100644
--- a/docs/man/pkcheck.xml
+++ b/docs/man/pkcheck.xml
@@ -55,6 +55,9 @@
<arg choice="plain">
<replaceable>pid,pid-start-time</replaceable>
</arg>
+ <arg choice="plain">
+ <replaceable>pid,pid-start-time,uid</replaceable>
+ </arg>
</group>
</arg>
<arg choice="plain">
@@ -90,7 +93,7 @@
<title>DESCRIPTION</title>
<para>
<command>pkcheck</command> is used to check whether a process, specified by
- either <option>--process</option> or <option>--system-bus-name</option>,
+ either <option>--process</option> (see below) or <option>--system-bus-name</option>,
is authorized for <replaceable>action</replaceable>. The <option>--detail</option>
option can be used zero or more times to pass details about <replaceable>action</replaceable>.
If <option>--allow-user-interaction</option> is passed, <command>pkcheck</command> blocks
@@ -160,15 +163,23 @@ KEY3=VALUE3
<refsect1 id="pkcheck-notes">
<title>NOTES</title>
<para>
- Since process identifiers can be recycled, the caller should always use
- <replaceable>pid,pid-start-time</replaceable> to specify the process
- to check for authorization when using the <option>--process</option> option.
- The value of <replaceable>pid-start-time</replaceable>
- can be determined by consulting e.g. the
+ Do not use either the bare <replaceable>pid</replaceable> or
+ <replaceable>pid,start-time</replaceable> syntax forms for
+ <option>--process</option>. There are race conditions in both.
+ New code should always use
+ <replaceable>pid,pid-start-time,uid</replaceable>. The value of
+ <replaceable>start-time</replaceable> can be determined by
+ consulting e.g. the
<citerefentry><refentrytitle>proc</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- file system depending on the operating system. If only <replaceable>pid</replaceable>
- is passed to the <option>--process</option> option, then <command>pkcheck</command>
- will look up the start time itself but note that this may be racy.
+ file system depending on the operating system. If fewer than 3
+ arguments are passed, <command>pkcheck</command> will attempt to
+ look up them up internally, but note that this may be racy.
+ </para>
+ <para>
+ If your program is a daemon with e.g. a custom Unix domain
+ socket, you should determine the <replaceable>uid</replaceable>
+ parameter via operating system mechanisms such as
+ <literal>PEERCRED</literal>.
</para>
</refsect1>