Reorder P4 struct key initializers and blocks

The basic_routing.p4 program was failing verification due to missed map
key initializers in some paths. Put the goto label at the head of the
block and add a " = {}" for each key declaration inside the block.
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

use __builtin_memcpy() instead of unrolled loop

also remove tab and unused import
Signed-off-by: Alexei Starovoitov <ast@fb.com>

Added cachestat tool

Added .txt to exmaple file to allow link to work

duplicate file

duplicate of .txt version

  Author:    allan mcaleavy <allan.mcaleavy@gmail.com>

offwaketime

Update test_dump_func to be python3 compatible

Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

gethostlatency

bashreadline

more strlen examples

Add uprobe strlen histogram example

This example traces all calls to libc's strlen(). The program is attached as a
retprobe, therefore giving access to the resulting string length. The value is
kept in a log2 histogram that is printed to console once per second.

Example:
```
$ sudo ./strlen_hist.py
22:12:51
     strlen return:      : count     distribution
         0 -> 1          : 2041     |****************                        |
         2 -> 3          : 1120     |********                                |
         4 -> 7          : 3300     |**************************              |
         8 -> 15         : 4995     |****************************************|
        16 -> 31         : 2130     |*****************                       |
        32 -> 63         : 562      |****                                    |
^C
```
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

Uprobe support

Use the full path invocation of objdump in both places.

Add a docstring for the variants of attach_retprobe.
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

The calculation of function address in non-shared libraries was
incorrect. Fix it.
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

This adds a similar set of functions to kprobes for userspace probes.
The calling convention is different, however, since the user must
provide a library/binary name and function symbol or address. Add two
simple test cases for both.

I don't see an easy way in this api to add auto-loading support, as in
kprobe functions that start with "kprobe__". Such niceties can come
later.
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

The base calling convention for uprobes is the same as kprobes, but just
the path in debug/tracing/ is slightly different. Add a new API for this
and slightly refactor the code.
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

wakeuptime

Add decode() to ascii string in offcputime.py

Fixes: #318
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

Updates to use cmake GLOB and libbcc.so.0 in python init

In order not to miss some files in the tools and examples source
directories, use cmake file(GLOB) to collect relevant files. To ease the
implementation, move all tools to be .py suffixed in the source, but
sans-suffix in the installation (same as before)

In addition, to prevent future API breakage confusion (though of course
that may still happen), use CDLL("libbcc.so.0") in the bcc __init__.py.

Fixes: #317
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

offcputime improvements

stack walker typo and improvement