1 | <?xml version="1.0" encoding="ISO-8859-1"?>
|
---|
2 | <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
|
---|
3 | "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
|
---|
4 | <!ENTITY % general-entities SYSTEM "../../general.ent">
|
---|
5 | %general-entities;
|
---|
6 | ]>
|
---|
7 |
|
---|
8 | <sect1 id="unpacking">
|
---|
9 | <?dbhtml filename="unpacking.html"?>
|
---|
10 |
|
---|
11 | <sect1info>
|
---|
12 | <othername>$LastChangedBy$</othername>
|
---|
13 | <date>$Date$</date>
|
---|
14 | </sect1info>
|
---|
15 |
|
---|
16 | <title>Notes on Building Software</title>
|
---|
17 |
|
---|
18 | <para>Those people who have built an LFS system may be aware
|
---|
19 | of the general principles of downloading and unpacking software. Some
|
---|
20 | of that information is repeated here for those new to building
|
---|
21 | their own software.</para>
|
---|
22 |
|
---|
23 | <para>Each set of installation instructions contains a URL from which you
|
---|
24 | can download the package. The patches; however, are stored on the LFS
|
---|
25 | servers and are available via HTTP. These are referenced as needed in the
|
---|
26 | installation instructions.</para>
|
---|
27 |
|
---|
28 | <para>While you can keep the source files anywhere you like, we assume that
|
---|
29 | you have unpacked the package and changed into the directory created by the
|
---|
30 | unpacking process (the 'build' directory). We also assume you have
|
---|
31 | uncompressed any required patches and they are in the directory immediately
|
---|
32 | above the 'build' directory.</para>
|
---|
33 |
|
---|
34 | <para>We can not emphasize strongly enough that you should start from a
|
---|
35 | <emphasis>clean source tree</emphasis> each time. This means that if
|
---|
36 | you have had an error during configuration or compilation, it's usually
|
---|
37 | best to delete the source tree and
|
---|
38 | re-unpack it <emphasis>before</emphasis> trying again. This obviously
|
---|
39 | doesn't apply if you're an advanced user used to hacking
|
---|
40 | <filename>Makefile</filename>s and C code, but if in doubt, start from a
|
---|
41 | clean tree.</para>
|
---|
42 |
|
---|
43 | <sect2>
|
---|
44 | <title>Building Software as an Unprivileged (non-root) User</title>
|
---|
45 |
|
---|
46 | <para>The golden rule of Unix System Administration is to use your
|
---|
47 | superpowers only when necessary. Hence, BLFS recommends that you
|
---|
48 | build software as an unprivileged user and only become the
|
---|
49 | <systemitem class='username'>root</systemitem> user when installing the
|
---|
50 | software. This philosophy is followed in all the packages in this book.
|
---|
51 | Unless otherwise specified, all instructions should be executed as an
|
---|
52 | unprivileged user. The book will advise you on instructions that need
|
---|
53 | <systemitem class='username'>root</systemitem> privileges.</para>
|
---|
54 |
|
---|
55 | </sect2>
|
---|
56 |
|
---|
57 | <sect2>
|
---|
58 | <title>Unpacking the Software</title>
|
---|
59 |
|
---|
60 | <para>If a file is in <filename class='extension'>.tar</filename> format
|
---|
61 | and compressed, it is unpacked by running one of the following
|
---|
62 | commands:</para>
|
---|
63 |
|
---|
64 | <screen><userinput>tar -xvf filename.tar.gz
|
---|
65 | tar -xvf filename.tgz
|
---|
66 | tar -xvf filename.tar.Z
|
---|
67 | tar -xvf filename.tar.bz2</userinput></screen>
|
---|
68 |
|
---|
69 | <note>
|
---|
70 | <para>You may omit using the <option>v</option> parameter in the commands
|
---|
71 | shown above and below if you wish to suppress the verbose listing of all
|
---|
72 | the files in the archive as they are extracted. This can help speed up the
|
---|
73 | extraction as well as make any errors produced during the extraction
|
---|
74 | more obvious to you.</para>
|
---|
75 | </note>
|
---|
76 |
|
---|
77 | <para>You can also use a slightly different method:</para>
|
---|
78 |
|
---|
79 | <screen><userinput>bzcat filename.tar.bz2 | tar -xv</userinput></screen>
|
---|
80 |
|
---|
81 | <para>Finally, you sometimes need to be able to unpack patches which are
|
---|
82 | generally not in <filename class='extension'>.tar</filename> format. The
|
---|
83 | best way to do this is to copy the patch file to the parent of the 'build'
|
---|
84 | directory and then run one of the following commands depending on whether
|
---|
85 | the file is a <filename class='extension'>.gz</filename> or <filename
|
---|
86 | class='extension'>.bz2</filename> file:</para>
|
---|
87 |
|
---|
88 | <screen><userinput>gunzip -v patchname.gz
|
---|
89 | bunzip2 -v patchname.bz2</userinput></screen>
|
---|
90 |
|
---|
91 | </sect2>
|
---|
92 |
|
---|
93 | <sect2>
|
---|
94 | <title>Verifying File Integrity Using 'md5sum'</title>
|
---|
95 |
|
---|
96 | <para>Generally, to verify that the downloaded file is genuine and complete,
|
---|
97 | many package maintainers also distribute md5sums of the files. To verify the
|
---|
98 | md5sum of the downloaded files, download both the file and the
|
---|
99 | corresponding md5sum file to the same directory (preferably from different
|
---|
100 | on-line locations), and (assuming <filename>file.md5sum</filename> is the
|
---|
101 | md5sum file downloaded) run the following command:</para>
|
---|
102 |
|
---|
103 | <screen><userinput>md5sum -c file.md5sum</userinput></screen>
|
---|
104 |
|
---|
105 | <para>If there are any errors, they will be reported. Note that the BLFS
|
---|
106 | book includes md5sums for all the source files also. To use the BLFS
|
---|
107 | supplied md5sums, you can create a <filename>file.md5sum</filename> (place
|
---|
108 | the md5sum data and the exact name of the downloaded file on the same
|
---|
109 | line of a file, separated by white space) and run the command shown above.
|
---|
110 | Alternately, simply run the command shown below and compare the output
|
---|
111 | to the md5sum data shown in the BLFS book.</para>
|
---|
112 |
|
---|
113 | <screen><userinput>md5sum <replaceable><name_of_downloaded_file></replaceable></userinput></screen>
|
---|
114 |
|
---|
115 | </sect2>
|
---|
116 |
|
---|
117 | <sect2>
|
---|
118 | <title>Creating Log Files During Installation</title>
|
---|
119 |
|
---|
120 | <para>For larger packages, it is convenient to create log files instead of
|
---|
121 | staring at the screen hoping to catch a particular error or warning. Log
|
---|
122 | files are also useful for debugging and keeping records. The following
|
---|
123 | command allows you to create an installation log. Replace
|
---|
124 | <replaceable><command></replaceable> with the command you intend to execute.</para>
|
---|
125 |
|
---|
126 | <screen><userinput>( <replaceable><command></replaceable> 2>&1 | tee compile.log && exit $PIPESTATUS )</userinput></screen>
|
---|
127 |
|
---|
128 | <para><option>2>&1</option> redirects error messages to the same
|
---|
129 | location as standard output. The <command>tee</command> command allows
|
---|
130 | viewing of the output while logging the results to a file. The parentheses
|
---|
131 | around the command run the entire command in a subshell and finally the
|
---|
132 | <command>exit $PIPESTATUS</command> command ensures the result of the
|
---|
133 | <replaceable><command></replaceable> is returned as the result and not the
|
---|
134 | result of the <command>tee</command> command.</para>
|
---|
135 |
|
---|
136 | </sect2>
|
---|
137 |
|
---|
138 | <sect2 id="automating-builds" xreflabel="Automated Building Procedures">
|
---|
139 | <title>Automated Building Procedures</title>
|
---|
140 |
|
---|
141 | <para>There are times when automating the building of a package can come in
|
---|
142 | handy. Everyone has their own reasons for wanting to automate building,
|
---|
143 | and everyone goes about it in their own way. Creating
|
---|
144 | <filename>Makefile</filename>s, <application>Bash</application> scripts,
|
---|
145 | <application>Perl</application> scripts or simply a list of commands used
|
---|
146 | to cut and paste are just some of the methods you can use to automate
|
---|
147 | building BLFS packages. Detailing how and providing examples of the many
|
---|
148 | ways you can automate the building of packages is beyond the scope of this
|
---|
149 | section. This section will expose you to using file redirection and the
|
---|
150 | <command>yes</command> command to help provide ideas on how to automate
|
---|
151 | your builds.</para>
|
---|
152 |
|
---|
153 | <bridgehead renderas="sect3">File Redirection to Automate Input</bridgehead>
|
---|
154 |
|
---|
155 | <para>You will find times throughout your BLFS journey when you will come
|
---|
156 | across a package that has a command prompting you for information. This
|
---|
157 | information might be configuration details, a directory path, or a response
|
---|
158 | to a license agreement. This can present a challenge to automate the
|
---|
159 | building of that package. Occasionally, you will be prompted for different
|
---|
160 | information in a series of questions. One method to automate this type of
|
---|
161 | scenario requires putting the desired responses in a file and using
|
---|
162 | redirection so that the program uses the data in the file as the answers to
|
---|
163 | the questions.</para>
|
---|
164 |
|
---|
165 | <para>Building the <application>CUPS</application> package is a good
|
---|
166 | example of how redirecting a file as input to prompts can help you automate
|
---|
167 | the build. If you run the test suite, you are asked to respond to a series
|
---|
168 | of questions regarding the type of test to run and if you have any
|
---|
169 | auxiliary programs the test can use. You can create a file with your
|
---|
170 | responses, one response per line, and use a command similar to the
|
---|
171 | one shown below to automate running the test suite:</para>
|
---|
172 |
|
---|
173 | <screen><userinput>make check < ../cups-1.1.23-testsuite_parms</userinput></screen>
|
---|
174 |
|
---|
175 | <para>This effectively makes the test suite use the responses in the file
|
---|
176 | as the input to the questions. Occasionally you may end up doing a bit of
|
---|
177 | trial and error determining the exact format of your input file for some
|
---|
178 | things, but once figured out and documented you can use this to automate
|
---|
179 | building the package.</para>
|
---|
180 |
|
---|
181 | <bridgehead renderas="sect3">Using <command>yes</command> to Automate
|
---|
182 | Input</bridgehead>
|
---|
183 |
|
---|
184 | <para>Sometimes you will only need to provide one response, or provide the
|
---|
185 | same response to many prompts. For these instances, the
|
---|
186 | <command>yes</command> command works really well. The
|
---|
187 | <command>yes</command> command can be used to provide a response (the same
|
---|
188 | one) to one or more instances of questions. It can be used to simulate
|
---|
189 | pressing just the <keycap>Enter</keycap> key, entering the
|
---|
190 | <keycap>Y</keycap> key or entering a string of text. Perhaps the easiest
|
---|
191 | way to show its use is in an example.</para>
|
---|
192 |
|
---|
193 | <para>First, create a short <application>Bash</application> script by
|
---|
194 | entering the following commands:</para>
|
---|
195 |
|
---|
196 | <screen><userinput>cat > blfs-yes-test1 << "EOF"
|
---|
197 | <literal>#!/bin/bash
|
---|
198 |
|
---|
199 | echo -n -e "\n\nPlease type something (or nothing) and press Enter ---> "
|
---|
200 |
|
---|
201 | read A_STRING
|
---|
202 |
|
---|
203 | if test "$A_STRING" = ""; then A_STRING="Just the Enter key was pressed"
|
---|
204 | else A_STRING="You entered '$A_STRING'"
|
---|
205 | fi
|
---|
206 |
|
---|
207 | echo -e "\n\n$A_STRING\n\n"</literal>
|
---|
208 | EOF
|
---|
209 | chmod 755 blfs-yes-test1</userinput></screen>
|
---|
210 |
|
---|
211 | <para>Now run the script by issuing <command>./blfs-yes-test1</command> from
|
---|
212 | the command line. It will wait for a response, which can be anything (or
|
---|
213 | nothing) followed by the <keycap>Enter</keycap> key. After entering
|
---|
214 | something, the result will be echoed to the screen. Now use the
|
---|
215 | <command>yes</command> command to automate the entering of a
|
---|
216 | response:</para>
|
---|
217 |
|
---|
218 | <screen><userinput>yes | ./blfs-yes-test1</userinput></screen>
|
---|
219 |
|
---|
220 | <para>Notice that piping <command>yes</command> by itself to the script
|
---|
221 | results in <keycap>y</keycap> being passed to the script. Now try it with a
|
---|
222 | string of text:</para>
|
---|
223 |
|
---|
224 | <screen><userinput>yes 'This is some text' | ./blfs-yes-test1</userinput></screen>
|
---|
225 |
|
---|
226 | <para>The exact string was used as the response to the script. Finally,
|
---|
227 | try it using an empty (null) string:</para>
|
---|
228 |
|
---|
229 | <screen><userinput>yes '' | ./blfs-yes-test1</userinput></screen>
|
---|
230 |
|
---|
231 | <para>Notice this results in passing just the press of the
|
---|
232 | <keycap>Enter</keycap> key to the script. This is useful for times when the
|
---|
233 | default answer to the prompt is sufficient. This syntax is used in the
|
---|
234 | <xref linkend="net-tools-automate-example"/> instructions to accept all the
|
---|
235 | defaults to the many prompts during the configuration step. You may now
|
---|
236 | remove the test script, if desired.</para>
|
---|
237 |
|
---|
238 | <bridgehead renderas="sect3">File Redirection to Automate Output</bridgehead>
|
---|
239 |
|
---|
240 | <para>In order to automate the building of some packages, especially those
|
---|
241 | that require you to read a license agreement one page at a time, requires
|
---|
242 | using a method that avoids having to press a key to display each page.
|
---|
243 | Redirecting the output to a file can be used in these instances to assist
|
---|
244 | with the automation. The previous section on this page touched on creating
|
---|
245 | log files of the build output. The redirection method shown there used the
|
---|
246 | <command>tee</command> command to redirect output to a file while also
|
---|
247 | displaying the output to the screen. Here, the output will only be sent to
|
---|
248 | a file.</para>
|
---|
249 |
|
---|
250 | <para>Again, the easiest way to demonstrate the technique is to show an
|
---|
251 | example. First, issue the command:</para>
|
---|
252 |
|
---|
253 | <screen><userinput>ls -l /usr/bin | more</userinput></screen>
|
---|
254 |
|
---|
255 | <para>Of course, you'll be required to view the output one page at a time
|
---|
256 | because the <command>more</command> filter was used. Now try the same
|
---|
257 | command, but this time redirect the output to a file. The special file
|
---|
258 | <filename>/dev/null</filename> can be used instead of the filename shown,
|
---|
259 | but you will have no log file to examine:</para>
|
---|
260 |
|
---|
261 | <screen><userinput>ls -l /usr/bin | more > redirect_test.log 2>&1</userinput></screen>
|
---|
262 |
|
---|
263 | <para>Notice that this time the command immediately returned to the shell
|
---|
264 | prompt without having to page through the output. You may now remove the
|
---|
265 | log file.</para>
|
---|
266 |
|
---|
267 | <para>The last example will use the <command>yes</command> command in
|
---|
268 | combination with output redirection to bypass having to page through the
|
---|
269 | output and then provide a <keycap>y</keycap> to a prompt. This technique
|
---|
270 | could be used in instances when otherwise you would have to page through
|
---|
271 | the output of a file (such as a license agreement) and then answer the
|
---|
272 | question of <quote>do you accept the above?</quote>. For this example,
|
---|
273 | another short <application>Bash</application> script is required:</para>
|
---|
274 |
|
---|
275 | <screen><userinput>cat > blfs-yes-test2 << "EOF"
|
---|
276 | <literal>#!/bin/bash
|
---|
277 |
|
---|
278 | ls -l /usr/bin | more
|
---|
279 |
|
---|
280 | echo -n -e "\n\nDid you enjoy reading this? (y,n) "
|
---|
281 |
|
---|
282 | read A_STRING
|
---|
283 |
|
---|
284 | if test "$A_STRING" = "y"; then A_STRING="You entered the 'y' key"
|
---|
285 | else A_STRING="You did NOT enter the 'y' key"
|
---|
286 | fi
|
---|
287 |
|
---|
288 | echo -e "\n\n$A_STRING\n\n"</literal>
|
---|
289 | EOF
|
---|
290 | chmod 755 blfs-yes-test2</userinput></screen>
|
---|
291 |
|
---|
292 | <para>This script can be used to simulate a program that requires you to
|
---|
293 | read a license agreement, then respond appropriately to accept the
|
---|
294 | agreement before the program will install anything. First, run the script
|
---|
295 | without any automation techniques by issuing
|
---|
296 | <command>./blfs-yes-test2</command>.</para>
|
---|
297 |
|
---|
298 | <para>Now issue the following command which uses two automation techniques,
|
---|
299 | making it suitable for use in an automated build script:</para>
|
---|
300 |
|
---|
301 | <screen><userinput>yes | ./blfs-yes-test2 > blfs-yes-test2.log 2>&1</userinput></screen>
|
---|
302 |
|
---|
303 | <para>If desired, issue <command>tail blfs-yes-test2.log</command> to see
|
---|
304 | the end of the paged output, and confirmation that <keycap>y</keycap> was
|
---|
305 | passed through to the script. Once satisfied that it works as it should,
|
---|
306 | you may remove the script and log file.</para>
|
---|
307 |
|
---|
308 | <para>Finally, keep in mind that there are many ways to automate and/or
|
---|
309 | script the build commands. There is not a single <quote>correct</quote> way
|
---|
310 | to do it. Your imagination is the only limit.</para>
|
---|
311 |
|
---|
312 | </sect2>
|
---|
313 |
|
---|
314 | <sect2>
|
---|
315 | <title>Dependencies</title>
|
---|
316 |
|
---|
317 | <para>For each package described, BLFS lists the known dependencies.
|
---|
318 | These are listed under several headings, whose meaning is as follows:</para>
|
---|
319 |
|
---|
320 | <itemizedlist>
|
---|
321 | <listitem>
|
---|
322 | <para><emphasis>Required</emphasis> means that the target package
|
---|
323 | cannot be correctly built without the dependency having first been
|
---|
324 | installed.</para>
|
---|
325 | </listitem>
|
---|
326 | <listitem>
|
---|
327 | <para><emphasis>Recommended</emphasis> means that BLFS strongly
|
---|
328 | suggests this package is installed first for a clean and trouble-free
|
---|
329 | build, that won't have issues either during the build process, or at
|
---|
330 | run-time. The instructions in the book assume these packages are
|
---|
331 | installed. Some changes or workarounds may be required if these
|
---|
332 | packages are not installed.</para>
|
---|
333 | </listitem>
|
---|
334 | <listitem>
|
---|
335 | <para><emphasis>Optional</emphasis> means that this package might be
|
---|
336 | installed for added functionality. Often BLFS will describe the
|
---|
337 | dependency to explain the added functionality that will result.</para>
|
---|
338 | </listitem>
|
---|
339 | </itemizedlist>
|
---|
340 |
|
---|
341 | </sect2>
|
---|
342 |
|
---|
343 | <sect2 id="package_updates">
|
---|
344 | <title>Using the Most Current Package Sources</title>
|
---|
345 |
|
---|
346 | <para>On occasion you may run into a situation in the book when a package
|
---|
347 | will not build or work properly. Though the Editors attempt to ensure
|
---|
348 | that every package in the book builds and works properly, sometimes a
|
---|
349 | package has been overlooked or was not tested with this particular version
|
---|
350 | of BLFS.</para>
|
---|
351 |
|
---|
352 | <para>If you discover that a package will not build or work properly, you
|
---|
353 | should see if there is a more current version of the package. Typically
|
---|
354 | this means you go to the maintainer's web site and download the most current
|
---|
355 | tarball and attempt to build the package. If you cannot determine the
|
---|
356 | maintainer's web site by looking at the download URLs, use Google and query
|
---|
357 | the package's name. For example, in the Google search bar type:
|
---|
358 | 'package_name download' (omit the quotes) or something similar. Sometimes
|
---|
359 | typing: 'package_name home page' will result in you finding the
|
---|
360 | maintainer's web site.</para>
|
---|
361 |
|
---|
362 | </sect2>
|
---|
363 |
|
---|
364 | <sect2 id="stripping">
|
---|
365 | <title>Stripping One More Time</title>
|
---|
366 |
|
---|
367 | <para>In LFS, stripping of debugging symbols was discussed a couple of
|
---|
368 | times. When building BLFS packages, there are generally no special
|
---|
369 | instructions that discuss stripping again. It is probably not a good
|
---|
370 | idea to strip an executable or a library while it is in use, so exiting
|
---|
371 | any windowing environment is a good idea. Then you can do:</para>
|
---|
372 |
|
---|
373 | <screen><userinput>find /{,usr/}{bin,lib,sbin} -type f -exec strip --strip-unneeded {} \;</userinput></screen>
|
---|
374 |
|
---|
375 | <para>If you install programs in other directories such as /opt or /usr/local,
|
---|
376 | you may want to strip the files there too.</para>
|
---|
377 |
|
---|
378 | <para>For more information on stripping, see <ulink
|
---|
379 | url="http://www.technovelty.org/linux/stripping-shared-libraries.html"/>.</para>
|
---|
380 |
|
---|
381 | </sect2>
|
---|
382 |
|
---|
383 | <sect2 id="libtool">
|
---|
384 | <title>Libtool files</title>
|
---|
385 |
|
---|
386 | <para>One of the side effects of packages that use Autotools, including
|
---|
387 | libtool, is that they create many files with an .la extension. These
|
---|
388 | files are not needed in an LFS environment. If there are conflicts with
|
---|
389 | pkgconfig entries, they can actually prevent successful builds. You
|
---|
390 | may want to consider removing these files periodically:</para>
|
---|
391 |
|
---|
392 | <screen><userinput>find /lib /usr/lib -not -path "*Image*" -a -name \*.la -delete</userinput></screen>
|
---|
393 |
|
---|
394 | <para>The above command removes all .la files with the exception of those that have
|
---|
395 | "Image" as a part of the path. These .la files are used by the
|
---|
396 | ImageMagick programs. There may be other exceptions by packages not in BLFS.</para>
|
---|
397 |
|
---|
398 | </sect2>
|
---|
399 |
|
---|
400 | </sect1>
|
---|