Merge pull request #24 from egmc/debug-build

add debug build process

Author: egmc

Makefile

@@ -1,4 +1,6 @@
-.PHONY: all clean build ebpf go-build vmlinux build-libbpf test
+.PHONY: all clean build ebpf ebpf-debug go-build vmlinux build-libbpf test debug
+
+EBPF_CFLAGS ?=
 
 # Default target
 all: vmlinux ebpf go-build
@@ -15,7 +17,14 @@ vmlinux:
 
 # eBPF compilation
 ebpf: vmlinux
-	clang -g -O2 -D__TARGET_ARCH_x86 -I./bpf  -I./dest/libbpf/usr/include -idirafter /usr/include/x86_64-linux-gnu -c bpf/php.bpf.c -target bpf -o bpf/php.bpf.o
+	clang -g -O2 -D__TARGET_ARCH_x86 $(EBPF_CFLAGS) -I./bpf  -I./dest/libbpf/usr/include -idirafter /usr/include/x86_64-linux-gnu -c bpf/php.bpf.c -target bpf -o bpf/php.bpf.o
+
+# eBPF compilation with debug (enables bpf_trace_printk)
+ebpf-debug:
+	$(MAKE) ebpf EBPF_CFLAGS=-DDEBUG
+
+# Debug build (eBPF with -DDEBUG + go binary)
+debug: ebpf-debug go-build
 
 # Go build
 go-build:

bpf/php.bpf.c

@@ -4,6 +4,16 @@
 
 #define MAX_STR_LEN 512
 
+#ifdef DEBUG
+#define debug_printk(fmt, ...)                              \
+    ({                                                      \
+        static const char ____fmt[] = fmt;                  \
+        bpf_trace_printk(____fmt, sizeof(____fmt), ##__VA_ARGS__); \
+    })
+#else
+#define debug_printk(fmt, ...) ((void)0)
+#endif
+
 char filename[MAX_STR_LEN];
 
 
@@ -19,8 +29,7 @@ int BPF_USDT(compile_file_return, char *arg0, char *arg1)
 {
     u64 ts = bpf_ktime_get_ns();
 
-    static const char fmtstr[] = "compile file return: %s, %s\n"; 
-    bpf_trace_printk(fmtstr, sizeof(fmtstr), arg0, arg1);
+    debug_printk("compile file return: %s, %s\n", arg0, arg1);
 
 
     bpf_probe_read_user_str(&filename, sizeof(filename), arg0);