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@@ -18,7 +18,7 @@
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<h2 class='titleHead'>The Linux Kernel Module Programming Guide</h2>
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<h2 class='titleHead'>The Linux Kernel Module Programming Guide</h2>
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<div class='author'><span class='ecrm-1200'>Peter Jay Salzman, Michael Burian, Ori Pomerantz, Bob Mottram, Jim Huang</span></div><br />
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<div class='author'><span class='ecrm-1200'>Peter Jay Salzman, Michael Burian, Ori Pomerantz, Bob Mottram, Jim Huang</span></div><br />
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-<div class='date'><span class='ecrm-1200'>March 9, 2022</span></div>
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+<div class='date'><span class='ecrm-1200'>March 16, 2022</span></div>
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@@ -1079,12 +1079,13 @@ code.
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</p><!-- l. 706 --><p class='indent'> Kernel modules are different here, too. In the hello world
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</p><!-- l. 706 --><p class='indent'> Kernel modules are different here, too. In the hello world
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example, you might have noticed that we used a function,
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example, you might have noticed that we used a function,
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<code> <span class='ectt-1000'>pr_info()</span>
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<code> <span class='ectt-1000'>pr_info()</span>
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-</code> but did not include a standard I/O library. That is because modules are object files whose symbols
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-get resolved upon <code> <span class='ectt-1000'>insmod</span>
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-</code>’ing. The definition for the symbols comes from the kernel itself; the only
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-external functions you can use are the ones provided by the kernel. If you’re
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-curious about what symbols have been exported by your kernel, take a look at
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-<span class='obeylines-h'><span class='verb'><span class='ectt-1000'>/proc/kallsyms</span></span></span>.
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+</code> but did not include a standard I/O library. That is because
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+modules are object files whose symbols get resolved upon running
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+<code> <span class='ectt-1000'>insmod</span>
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+</code> or <code> <span class='ectt-1000'>modprobe</span>
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+</code>. The definition for the symbols comes from the kernel itself; the only external
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+functions you can use are the ones provided by the kernel. If you’re curious about
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+what symbols have been exported by your kernel, take a look at <span class='obeylines-h'><span class='verb'><span class='ectt-1000'>/proc/kallsyms</span></span></span>.
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</p><!-- l. 711 --><p class='indent'> One point to keep in mind is the difference between library functions and system
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</p><!-- l. 711 --><p class='indent'> One point to keep in mind is the difference between library functions and system
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calls. Library functions are higher level, run completely in user space and
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calls. Library functions are higher level, run completely in user space and
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provide a more convenient interface for the programmer to the functions
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provide a more convenient interface for the programmer to the functions
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@@ -1103,13 +1104,13 @@ data into strings and write the string data using the low-level system call
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</code>? It is easy! Compile the following program:
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</code>? It is easy! Compile the following program:
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</p><!-- l. 1 --><p class='indent'>
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</p><!-- l. 1 --><p class='indent'>
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</p>
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</p>
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- <pre class='fancyvrb' id='fancyvrb35'><a id='x1-21016r1'></a><span class='ecrm-0500'>1</span><span id='textcolor259'><span class='ectt-0800'>#include</span></span><span class='ectt-0800'> </span><span id='textcolor260'><span class='ectt-0800'><stdio.h></span></span>
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-<a id='x1-21018r2'></a><span class='ecrm-0500'>2</span>
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-<a id='x1-21020r3'></a><span class='ecrm-0500'>3</span><span id='textcolor261'><span class='ectt-0800'>int</span></span><span class='ectt-0800'> main(</span><span id='textcolor262'><span class='ectt-0800'>void</span></span><span class='ectt-0800'>)</span>
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-<a id='x1-21022r4'></a><span class='ecrm-0500'>4</span><span class='ectt-0800'>{</span>
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-<a id='x1-21024r5'></a><span class='ecrm-0500'>5</span><span class='ectt-0800'> printf(</span><span id='textcolor263'><span class='ectt-0800'>"hello"</span></span><span class='ectt-0800'>);</span>
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-<a id='x1-21026r6'></a><span class='ecrm-0500'>6</span><span class='ectt-0800'> </span><span id='textcolor264'><span class='ectt-0800'>return</span></span><span class='ectt-0800'> 0;</span>
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-<a id='x1-21028r7'></a><span class='ecrm-0500'>7</span><span class='ectt-0800'>}</span></pre>
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+ <pre class='fancyvrb' id='fancyvrb35'><a id='x1-21017r1'></a><span class='ecrm-0500'>1</span><span id='textcolor259'><span class='ectt-0800'>#include</span></span><span class='ectt-0800'> </span><span id='textcolor260'><span class='ectt-0800'><stdio.h></span></span>
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+<a id='x1-21019r2'></a><span class='ecrm-0500'>2</span>
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+<a id='x1-21021r3'></a><span class='ecrm-0500'>3</span><span id='textcolor261'><span class='ectt-0800'>int</span></span><span class='ectt-0800'> main(</span><span id='textcolor262'><span class='ectt-0800'>void</span></span><span class='ectt-0800'>)</span>
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+<a id='x1-21023r4'></a><span class='ecrm-0500'>4</span><span class='ectt-0800'>{</span>
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+<a id='x1-21025r5'></a><span class='ecrm-0500'>5</span><span class='ectt-0800'> printf(</span><span id='textcolor263'><span class='ectt-0800'>"hello"</span></span><span class='ectt-0800'>);</span>
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+<a id='x1-21027r6'></a><span class='ecrm-0500'>6</span><span class='ectt-0800'> </span><span id='textcolor264'><span class='ectt-0800'>return</span></span><span class='ectt-0800'> 0;</span>
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+<a id='x1-21029r7'></a><span class='ecrm-0500'>7</span><span class='ectt-0800'>}</span></pre>
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<!-- l. 729 --><p class='indent'> with <code> <span class='ectt-1000'>gcc -Wall -o hello hello.c</span>
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<!-- l. 729 --><p class='indent'> with <code> <span class='ectt-1000'>gcc -Wall -o hello hello.c</span>
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</code>. Run the executable with <code> <span class='ectt-1000'>strace ./hello</span>
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</code>. Run the executable with <code> <span class='ectt-1000'>strace ./hello</span>
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</code>. Are you impressed? Every line you see corresponds to a system call. <a href='https://strace.io/'>strace</a> is a
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</code>. Are you impressed? Every line you see corresponds to a system call. <a href='https://strace.io/'>strace</a> is a
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