This commit adds bpf_get_first_key helper, which gets the first key of
the map. It automatically tries to use the new Kernel functionality and
falls back to old Kernel behavior. This helps us unify the logic to walk
a map across different APIs (Python, C++, etc.)

Workaround for possible race in pyroute2.ipdb

In simulation.py, add a call to initdb() to force-refresh the netlink
socket and the interface list.
Signed-off-by: Brenden Blanco <bblanco@gmail.com>

remove trailing white spaces from source code files

Trailing white spaces cause problems with git.
Signed-off-by: Mauricio Vasquez B <mauricio.vasquez@polito.it>

Enable recursive scanf support for char[] as string

Improve the internal documentation for the reader and writer generated
functions in the case that u8[]=>"" is used.

Change one `+=` to `=`.
Signed-off-by: Brenden Blanco <bblanco@gmail.com>

When a bpf table contains i8[] in one of its keys/leaves, use "" to
enclose the value, rather than [ %i %i %i ... ] format. This simplifies
the code that is generated for cases such as #1154, and brings it back
under ~200ms code generation, instead of >30s. This change of format is
not particularly robust (it doesn't handle escaping the doublequote
character itself), but it should make more sense for the common case,
such as tracing files and pathnames.

The test case included tests both the functionality of the format string
handling as well as the compile time, since test_clang already has an
implicit 10second timeout limit.

Fixes: #1154
Signed-off-by: Brenden Blanco <bblanco@gmail.com>

Fix bug when finding symbols for shared libraries

llvm5.0: use input kind helper to avoid breakage

Move FileDesc to separated header file and install

Upstream llvm renamed an enum, so use a helper function that is
available in all versions to fix compatibility.
Signed-off-by: Brenden Blanco <bblanco@gmail.com>

Use late-binding to finalize snprintf/sscanf

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

Fedora compile

The api should return 0, not the number of bytes successfully written
(which is what snprintf directly returns).
Signed-off-by: Brenden Blanco <bblanco@gmail.com>

Not all users require the snprintf/sscanf helpers, and in some types the
finalization can take a long time. Defer the finalization until the
first use. Wrap the invocation with a bound function such that the
BPFTable and other users don't need to keep an explicit BPFModule
reference. Use-after-free will be avoided by resetting the function to
an error-returning stub when/if the BPFModule is freed.
Signed-off-by: Brenden Blanco <bblanco@gmail.com>

Update compat header files and add bpf_probe_read_str

Also use it in the RecordMySQLQuery example and updated documentation

This commit updates the compat header files to 4.12-rc1

RFC: Improve mount namespace handling

This commit adds helper method in C API using `ProcMountNSGuard` to enter
and exit mount namespace, and use it in `libbpf.h`

This commit adds `ProcMountNS` and `ProcMountNSGuard`, that
automatically opens and closes FDs, and enters and exists mount
namespace on construction and destruction.

Improve perf map parsing logic

docs:  update feature list for 4.12

All of the features listed to be incluude in 4.12 landed in Linus' tree.
Update the table accordingly.

Fix computation of LUAJIT_INCLUDE_DIR

I don't think the current way cmake uses to locate the correct lua.h
works.  Entries like "include/foo.h" cause cmake to look for a file
like "/usr/include/include/foo.h".  I.e., the include/ prefix for
all the entries is wrong as is adding "include" at the end.

This patch removes the prefix.  With it bcc finally compiles on
Fedora.

If this change causes a problem there is something seriously wrong
with cmake.

Add documentation to guide future scripts to be Python3-ready

I cannot say that I understand the purpose behind the match_so_flags
function.  Is it supposed to be an exhaustive check?  Just a quick
check?  Is it always required to find the DSO which would be used
by the current process?  Should there be an overwrite?

In any case, the current way seems to be wholly inadequate.  It
somehow assumes a specific order of the DSO in the list read from
the ld.so cache.  That's fragile at best.

In the case of one of my machines, I run a x86-64 process and try
to find a symbol in libc.  The first DSO returned in the cache
matching "libc.so" is /libx32/libc.so.6 (i.e., the x32 version of
libc).  Using the file works but the DSO is not used.

I assume the idea behind the short form "c" for the module name
is to use the DSO of the same type as the running process.  As is
all platforms not matching the listed 64-bit platforms are blindly
accepted.

I suggest at the very least to check for the case of the non-64-bit
DSO in the cache to check that the running program is also 32-bit.
This patch does this.

In the longer run a more robust check should be implemented which
compares the current process' ELF header with that of the found DSO.
If this is the desired direction let me know and I'll come up with
a patch.

Some Linux distributions (at least Fedora and RHEL) do not provide
libluajit as an archive and instead only as a DSO.  Using the DSO
does not have any negative impact but the cmake script does not
check for the DSO files and instead fails to find luajit.

This simple change causes cmake to find the file as named in the
above distributions.  Maybe more change or a generalized method are
needed in future.  The prefered way to detect the DSO for Fedora/RHEL
would be to use pkgconfig but I don't propose to use it at this time.

docs: update features list (ThunderX support for XDP)

cc: Work around verifier error when reading USDT probe arguments