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escape segment names ... Markdown! 😧

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Sami Samhuri 2014-06-23 21:43:45 -07:00
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public/posts/2010/01/basics-of-the-mach-o-file-format.md
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@ -34,7 +34,7 @@ Apple's Mach-O overview</a>, which illustrates this quite nicely.</p>
<p>A very basic Mach object file consists of a header followed by single <p>A very basic Mach object file consists of a header followed by single
blob of machine code. That blob could be described by a single blob of machine code. That blob could be described by a single
section named __text, inside a single nameless segment. Here's a section named \_\_text, inside a single nameless segment. Here's a
diagram showing the layout of such a file:</p> diagram showing the layout of such a file:</p>
<pre> <pre>
@ -77,7 +77,7 @@ is where in memory segments will ultimately end up.</p>
<p>Names are optional and can be arbitrary, but the convention is to <p>Names are optional and can be arbitrary, but the convention is to
name segments with uppercase letters preceded by two underscores, name segments with uppercase letters preceded by two underscores,
e.g. __DATA or __TEXT </p> e.g. \_\_DATA or \_\_TEXT </p>
<p>The code exposes some more details about segment commands, but should <p>The code exposes some more details about segment commands, but should
be easy enough to follow.</p> be easy enough to follow.</p>
@ -101,7 +101,7 @@ everything in memory the addresses inside our machine code will need
to be updated.</p> to be updated.</p>
<p>By convention segments are named with lowercase letters preceded by <p>By convention segments are named with lowercase letters preceded by
two underscores, e.g. __bss or __text</p> two underscores, e.g. \_\_bss or \_\_text</p>
<p>Finally, the Ruby code describing section structs:</p> <p>Finally, the Ruby code describing section structs:</p>
@ -130,9 +130,9 @@ beasts.</p>
<p>If you want to see the actual data for a section otool provides a <p>If you want to see the actual data for a section otool provides a
couple of ways to do this. The first is to use couple of ways to do this. The first is to use
<code>otool -d &lt;segment&gt; &lt;section&gt;</code> for an arbitrary <code>otool -d &lt;segment&gt; &lt;section&gt;</code> for an arbitrary
section. To see the contents of a well-known section, such as __text section. To see the contents of a well-known section, such as \_\_text
in the __TEXT segment, use <code>otool -t /usr/bin/true</code>. You can in the \_\_TEXT segment, use <code>otool -t /usr/bin/true</code>. You can
also disassemble the __text section with also disassemble the \_\_text section with
<code>otool -tv /usr/bin/true</code>.</p> <code>otool -tv /usr/bin/true</code>.</p>
<p>You'll get to know otool quite well if you work with Mach-O.</p> <p>You'll get to know otool quite well if you work with Mach-O.</p>
@ -151,8 +151,8 @@ the next post we'll be there.</p>
<p><i>(You can almost do that with what we know now. If you <p><i>(You can almost do that with what we know now. If you
create a Mach file with a Mach header (ncmds=1), a single unnamed create a Mach file with a Mach header (ncmds=1), a single unnamed
segment (nsects=1), and then a section named __text with a segment segment (nsects=1), and then a section named \_\_text with a segment
name of __TEXT, and some x86 machine code as the section data, you name of \_\_TEXT, and some x86 machine code as the section data, you
would almost have a useful Mach object file.)</i></p> would almost have a useful Mach object file.)</i></p>
<p>Until next time, happy hacking!</p> <p>Until next time, happy hacking!</p>