<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/linux.git/tools/perf/util/trace_augment.h, branch v6.12.80</title>
<subtitle>Linux kernel stable tree (mirror)</subtitle>
<id>https://git.radix-linux.su/kernel/linux.git/atom?h=v6.12.80</id>
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<updated>2024-09-10T12:52:13+00:00</updated>
<entry>
<title>perf trace: Pretty print buffer data</title>
<updated>2024-09-10T12:52:13+00:00</updated>
<author>
<name>Howard Chu</name>
<email>howardchu95@gmail.com</email>
</author>
<published>2024-08-24T16:33:19+00:00</published>
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<id>urn:sha1:b257fac12f38d7f503b932313d704cee21092350</id>
<content type='text'>
Define TRACE_AUG_MAX_BUF in trace_augment.h data, which is the maximum
buffer size we can augment. BPF will include this header too.

Print buffer in a way that's different than just printing a string, we
print all the control characters in \digits (such as \0 for null, and
\10 for newline, LF).

For character that has a bigger value than 127, we print the digits
instead of the character itself as well.

Committer notes:

Simplified the buffer scnprintf to avoid using multiple buffers as
discussed in the patch review thread.

We can't really all 'buf' args to SCA_BUF as we're collecting so far
just on the sys_enter path, so we would be printing the previous 'read'
arg buffer contents, not what the kernel puts there.

So instead of:
   static int syscall_fmt__cmp(const void *name, const void *fmtp)
  @@ -1987,8 +1989,6 @@ syscall_arg_fmt__init_array(struct syscall_arg_fmt *arg, struct tep_format_field
  -               else if (strstr(field-&gt;type, "char *") &amp;&amp; strstr(field-&gt;name, "buf"))
  -                       arg-&gt;scnprintf = SCA_BUF;

Do:

static const struct syscall_fmt syscall_fmts[] = {
  +       { .name     = "write",      .errpid = true,
  +         .arg = { [1] = { .scnprintf = SCA_BUF /* buf */, from_user = true, }, }, },

Signed-off-by: Howard Chu &lt;howardchu95@gmail.com&gt;
Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Kan Liang &lt;kan.liang@linux.intel.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lore.kernel.org/r/20240815013626.935097-8-howardchu95@gmail.com
Link: https://lore.kernel.org/r/20240824163322.60796-6-howardchu95@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
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