📄 0192-0194.html
字号:
<HTML>
<HEAD>
<TITLE>Maximum RPM (RPM):Inside the Spec File:EarthWeb Inc.-</TITLE>
<META NAME="ROBOTS" CONTENT="NOINDEX, NOFOLLOW">
<SCRIPT>
<!--
function displayWindow(url, width, height) {
var Win = window.open(url,"displayWindow",'width=' + width +
',height=' + height + ',resizable=1,scrollbars=yes');
}
//-->
</SCRIPT>
</HEAD>
-->
<!-- ISBN=0672311054 //-->
<!-- TITLE=Maximum RPM (RPM)//-->
<!-- AUTHOR=Edward Bailey//-->
<!-- PUBLISHER=Macmillan Computer Publishing//-->
<!-- IMPRINT=Sams//-->
<!-- CHAPTER=13 //-->
<!-- PAGES=0163-0204 //-->
<!-- UNASSIGNED1 //-->
<!-- UNASSIGNED2 //-->
<P><CENTER>
<a href="0188-0191.html">Previous</A> | <a href="../ewtoc.html">Table of Contents</A> | <a href="0195-0197.html">Next</A>
</CENTER></P>
<A NAME="PAGENUM-192"><P>Page 192</P></A>
<P>Here are the resulting commands:
</P>
<!-- CODE SNIP //-->
<PRE>
echo "Patch #0:"
patch -p0 -s < /usr/src/redhat/SOURCES/patch-zero
</PRE>
<!-- END CODE SNIP //-->
<P>The %patch macro nicely displays a message showing that a patch is being applied, and
then invokes the patch command to actually do the dirty work. There are two options to the
patch command:
</P>
<UL>
<LI> The -p option, which directs
patch to remove the specified number of slashes (and
any intervening directories) from the front of any filenames specified in the patch file.
In this case, nothing will be removed.
<LI> The -s option, which directs
patch to apply the patch without displaying any
informational messages. Only errors from patch will be displayed.
</UL>
<P>How did the %patch macro know which patch to apply? Keep in mind that, like the
source tag lines, every patch tag is numbered, starting at
0. The %patch macro, by default, applies the patch file named on the patch (or
patch0) tag line.
</P>
<B>
13.4.2.1. Specifying Which patch Tag to Use
</B>
<P>The %patch macro actually has two different ways to specify the
patch tag line it is to use. The first method is to simply append the number of the desired
patch tag to the end of the %patch macro itself. For example, in order to apply the patch specified on the
patch2 tag line, the following %patch macro could be used:
</P>
<!-- CODE SNIP //-->
<PRE>
%patch2
</PRE>
<!-- END CODE SNIP //-->
<P>The other approach is to use the -P option. This option is followed by the number of the
patch tag line desired. Therefore, this line is identical in function to the previous one:
</P>
<!-- CODE SNIP //-->
<PRE>
%patch -P 2
</PRE>
<!-- END CODE SNIP //-->
<P>Note that the -P option will not apply the file specified on the
patch0 line, by default. Therefore, if you choose to use the
-P option to specify patch numbers, you'll need to use the
following format when applying patch 0:
</P>
<!-- CODE SNIP //-->
<PRE>
%patch -P 0
</PRE>
<!-- END CODE SNIP //-->
<B>
13.4.2.2. -p <#>: Strip <#> Leading Slashes and Directories from
patch Filenames
</B>
<P>The -p (note the lowercase p!) option is sent directly to the
patch command. It is followed by a number, which specifies the number of leading slashes (and the directories in between)
to strip from any filenames present in the patch file. For more information on this option,
consult the patch man page.
</P>
<A NAME="PAGENUM-193"><P>Page 193</P></A>
<B>
13.4.2.3. -b <name>: Set the Backup File Extension to
<name>
</B>
<P>When the patch command is used to apply a patch, unmodified copies of the files patched
are renamed to end with the extension .orig. The
-b option is used to change the extension used by
patch. This is normally done when multiple patches are to be applied to a given file.
By doing this, copies of the file as it existed prior to each patch are readily available.
</P>
<B>
13.4.2.4. -E: Remove Empty Output Files
</B>
<P>The -E option is passed directly to the patch program. When
patch is run with the -E option, any output files that are empty after the patches have been applied are removed.
</P>
<P>Now let's take %patch on a test drive.
</P>
<B>
13.4.2.5. An Example of the %patch Macro in Action
</B>
<P>Using the sample patch tag lines we've used throughout this section, let's put together an
example and look at the resulting commands. In our example, the first patch to be applied
needs to have the root directory stripped. Its
%patch macro will look like this:
</P>
<!-- CODE SNIP //-->
<PRE>
%patch -p1
</PRE>
<!-- END CODE SNIP //-->
<P>The next patch is to be applied to files in the software's
lib subdirectory, so we'll need to add a cd command to get us there. We'll also need to strip an additional directory:
</P>
<!-- CODE SNIP //-->
<PRE>
cd lib
%patch -P 1 -p2
</PRE>
<!-- END CODE SNIP //-->
<P>Finally, the last patch is to be applied from the software's top-level directory, so we need to
cd back up a level. In addition, this patch modifies some files that were also patched the first
time, so we'll need to change the backup file extension:
</P>
<!-- CODE SNIP //-->
<PRE>
cd ..
%patch -P 2 -p1 -b .last-patch
</PRE>
<!-- END CODE SNIP //-->
<P>Here's what the %prep script (minus any %setup macros) looks like:
</P>
<!-- CODE SNIP //-->
<PRE>
%patch -p1
cd lib
%patch -P 1 -p2
cd ..
%patch -P 2 -p1 -b .last-patch
</PRE>
<!-- END CODE SNIP //-->
<P>And here's what the macros expand to:
</P>
<!-- CODE //-->
<PRE>
echo "Patch #0:"
patch -p1 -s < /usr/src/redhat/SOURCES/patch-zero
cd lib
echo "Patch #1:"
patch -p2 -s < /usr/src/redhat/SOURCES/patch-one
cd ..
echo "Patch #2:"
patch -p1 -b .last-patch -s < /usr/src/redhat/SOURCES/patch-two
</PRE>
<!-- END CODE //-->
<A NAME="PAGENUM-194"><P>Page 194</P></A>
<P>No surprises here. Note that the %setup macro leaves the current working directory set to
the software's top-level directory, so our cd commands with their relative paths will do the
right thing. Of course, we have environment variables available that could be used here, too.
</P>
<B>
13.4.2.6. Compressed Patch Files
</B>
<P>If a patch file is compressed with gzip, RPM will automatically decompress it
before applying the patch. Here's a compressed
patch file as specified in the spec file:
</P>
<!-- CODE SNIP //-->
<PRE>
Patch: bother-3.5-hack.patch.gz
</PRE>
<!-- END CODE SNIP //-->
<P>This is part of the script RPM will execute when the
%prep section is executed:
</P>
<!-- CODE //-->
<PRE>
echo Executing: %prep
...
echo "Patch #0:"
gzip -dc /usr/src/redhat/SOURCES/bother-3.5-hack.patch.gz | patch -p1 -s
...
</PRE>
<!-- END CODE //-->
<P>First, the patch file is decompressed using
gzip. The output from gzip is then piped into
patch.
</P>
<P>That's about it for RPM's macros. Next, let's take a look at the
%files list.
</P>
<H3>
13.5. The %files List
</H3>
<P>The %files list indicates to RPM which files on the build system are to be packaged. The
list consists of one file per line. The file may have one or more directives preceding it. These
directives give RPM additional information about the file.
</P>
<P>Normally, each file includes its full path. The path performs two functions. First, it
specifies the file's location on the build system. Second, it denotes where the file should be placed
when the package is to be installed. (This is not entirely the case when a relocatable package is
being built. For more information on relocatable packages, see Chapter 15.)
</P>
<P>For packages that create directories containing hundreds of files, it can be quite
cumbersome creating a list that contains every file. To make this situation a bit easier, if the
%files list contains a path to a directory, RPM will automatically package every file in that directory, as
well as every file in each subdirectory. Shell-style globbing, or wildcard expansion, can also be
used in the %files list.
</P>
<H3><A NAME="ch13_ 10">
13.6. Directives for the %files List
</A></H3>
<P>The %files list may contain a number of different directives. They are used to do the
following:
</P>
<UL>
<LI> Identify documentation and configuration files
<LI> Ensure that a file has the correct permissions and ownership set
</UL>
<P><CENTER>
<a href="0188-0191.html">Previous</A> | <a href="../ewtoc.html">Table of Contents</A> | <a href="0195-0197.html">Next</A>
</CENTER></P>
</td>
</tr>
</table>
<!-- begin footer information -->
</body></html>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -