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diff --git a/public/build-bash-1.html b/public/build-bash-1.html new file mode 100644 index 0000000..fcc612a --- /dev/null +++ b/public/build-bash-1.html @@ -0,0 +1,56 @@ +<!DOCTYPE html> +<html lang="en"> +<head> + <meta charset="utf-8"> + <title>Building Bash 1.14.7 on a modern system — Luke Shumaker</title> + <link rel="stylesheet" type="text/css" href="assets/style.css"> +</head> +<body> +<header><a href="/">Luke Shumaker</a> » <a href=/blog>blog</a> » build-bash-1</header> +<article> +<h1 id="building-bash-1.14.7-on-a-modern-system">Building Bash 1.14.7 on a modern system</h1> +<p>In a previous revision of my <a href="./bash-arrays.html">Bash arrays post</a>, I wrote:</p> +<blockquote> +<p>Bash 1.x won't compile with modern GCC, so I couldn't verify how it behaves.</p> +</blockquote> +<p>I recall spending a little time fighting with it, but apparently I didn't try very hard: getting Bash 1.14.7 to build on a modern box is mostly just adjusting it to use <code>stdarg</code> instead of the no-longer-implemented <code>varargs</code>. There's also a little fiddling with the pre-autoconf automatic configuration.</p> +<h2 id="stdarg">stdarg</h2> +<p>Converting to <code>stdarg</code> is pretty simple: For each variadic function (functions that take a variable number of arguments), follow these steps:</p> +<ol type="1"> +<li>Replace <code>#include <varargs.h></code> with <code>#include <stdarg.h></code></li> +<li>Replace <code>function_name (va_alist) va_dcl</code> with <code>function_name (char *format, ...)</code>.</li> +<li>Removing the declaration and assignment for <code>format</code> from the function body.</li> +<li>Replace <code>va_start (args);</code> with <code>va_start (args, format);</code> in the function bodies.</li> +<li>Replace <code>function_name ();</code> with <code>function_name (char *, ...)</code> in header files and/or at the top of C files.</li> +</ol> +<p>There's one function that uses the variable name <code>control</code> instead of <code>format</code>.</p> +<p>I've prepared <a href="./bash-1.14.7-gcc4-stdarg.patch">a patch</a> that does this.</p> +<h2 id="configuration">Configuration</h2> +<p>Instead of using autoconf-style tests to test for compiler and platform features, Bash 1 used the file <code>machines.h</code> that had <code>#ifdefs</code> and a huge database of of different operating systems for different platforms. It's gross. And quite likely won't handle your modern operating system.</p> +<p>I made these two small changes to <code>machines.h</code> to get it to work correctly on my box:</p> +<ol type="1"> +<li>Replace <code>#if defined (i386)</code> with <code>#if defined (i386) || defined (__x86_64__)</code>. The purpose of this is obvious.</li> +<li>Add <code>#define USE_TERMCAP_EMULATION</code> to the section for Linux [sic] on i386 (<code># if !defined (done386) && (defined (__linux__) || defined (linux))</code>. What this does is tell it to link against libcurses to use curses termcap emulation, instead of linking against libtermcap (which doesn't exist on modern GNU/Linux systems).</li> +</ol> +<p>Again, I've prepared <a href="./bash-1.14.7-machines-config.patch">a patch</a> that does this.</p> +<h2 id="building">Building</h2> +<p>With those adjustments, it should build, but with quite a few warnings. Making a couple of changes to <code>CFLAGS</code> should fix that:</p> +<pre><code>make CFLAGS='-O -g -Werror -Wno-int-to-pointer-cast -Wno-pointer-to-int-cast -Wno-deprecated-declarations -include stdio.h -include stdlib.h -include string.h -Dexp2=bash_exp2'</code></pre> +<p>That's a doozy! Let's break it down:</p> +<ul> +<li><code>-O -g</code> The default value for CFLAGS (defined in <code>cpp-Makefile</code>)</li> +<li><code>-Werror</code> Treat warnings as errors; force us to deal with any issues.</li> +<li><code>-Wno-int-to-pointer-cast -Wno-pointer-to-int-cast</code> Allow casting between integers and pointers. Unfortunately, the way this version of Bash was designed requires this.</li> +<li><code>-Wno-deprecated-declarations</code> The <code>getwd</code> function in <code>unistd.h</code> is considered deprecated (use <code>getcwd</code> instead). However, if <code>getcwd</code> is available, Bash uses it's own <code>getwd</code> wrapper around <code>getcwd</code> (implemented in <code>general.c</code>), and only uses the signature from <code>unistd.h</code>, not the actuall implementation from libc.</li> +<li><code>-include stdio.h -include stdlib.h -include string.h</code> Several files are missing these header file includes. If not for <code>-Werror</code>, the default function signature fallbacks would work.</li> +<li><code>-Dexp2=bash_exp2</code> Avoid a conflict between the parser's <code>exp2</code> helper function and <code>math.h</code>'s base-2 exponential function.</li> +</ul> +<p>Have fun, software archaeologists!</p> + +</article> +<footer> +<p>The content of this page is Copyright © 2015 <a href="mailto:lukeshu@sbcglobal.net">Luke Shumaker</a>.</p> +<p>This page is licensed under the <a href="https://creativecommons.org/licenses/by-sa/3.0/">CC BY-SA-3.0</a> license.</p> +</footer> +</body> +</html> |