tracing: copy loader using a standard Makefile target

Use the XDP_LOADER makefile variable to copy the xdp_loader program to the
tracing01-xdp-simple and tracing03-xdp-debug-print assignments.  The previous
version used the ../basic02-prog-by-name/xdp_loader path which may not exist.
Using the XDP_LOADER variable builds the xdp_loader automatically.

Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>

Author: aspsk

tracing01-xdp-simple/Makefile

@@ -4,6 +4,8 @@
 XDP_TARGETS  := trace_prog_kern xdp_prog_kern
 USER_TARGETS := trace_load_and_stats
 
+COPY_LOADER = xdp_loader
+
 LIBBPF_DIR = ../libbpf/src/
 COMMON_DIR = ../common/
 

tracing01-xdp-simple/README.org

@@ -171,7 +171,7 @@ $ sudo ../testenv/testenv.sh setup --name veth-basic02
 Load the XDP program, tak produces aborted packets:
 
 #+begin_example sh
-$ sudo ../basic02-prog-by-name/xdp_loader --dev veth-basic02 --force --progsec xdp_abort
+$ sudo ./xdp_loader --dev veth-basic02 --force --progsec xdp_abort
 #+end_example
 
 and make some packets:

tracing03-xdp-debug-print/Makefile

@@ -3,6 +3,8 @@
 XDP_TARGETS := xdp_prog_kern
 USER_TARGETS := trace_read
 
+COPY_LOADER = xdp_loader
+
 LLC ?= llc
 CLANG ?= clang
 CC := gcc

tracing03-xdp-debug-print/README.org

@@ -90,7 +90,7 @@ Load XDP program from xdp_prog_kern.o that will print
 ethertnet header on every incoming packet:
 
 #+begin_example sh
-$ sudo ../basic02-prog-by-name/xdp_loader --dev veth-basic02 --force --progsec xdp
+$ sudo ./xdp_loader --dev veth-basic02 --force --progsec xdp
 #+end_example
 
 and make some packets: