bpf_headers: add bpf_printf() helper macro
(pulled from my notes / in-progress work on non-Android clat implementation)
Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Iae662f542be371c4110205c8c3bef0a416b47566
diff --git a/bpf/headers/include/bpf_helpers.h b/bpf/headers/include/bpf_helpers.h
index c94f1d8..ca0ca76 100644
--- a/bpf/headers/include/bpf_helpers.h
+++ b/bpf/headers/include/bpf_helpers.h
@@ -383,13 +383,17 @@
static int (*bpf_probe_read_user_str)(void* dst, int size, const void* unsafe_ptr) = (void*) BPF_FUNC_probe_read_user_str;
static unsigned long long (*bpf_ktime_get_ns)(void) = (void*) BPF_FUNC_ktime_get_ns;
static unsigned long long (*bpf_ktime_get_boot_ns)(void) = (void*)BPF_FUNC_ktime_get_boot_ns;
-static int (*bpf_trace_printk)(const char* fmt, int fmt_size, ...) = (void*) BPF_FUNC_trace_printk;
static unsigned long long (*bpf_get_current_pid_tgid)(void) = (void*) BPF_FUNC_get_current_pid_tgid;
static unsigned long long (*bpf_get_current_uid_gid)(void) = (void*) BPF_FUNC_get_current_uid_gid;
static unsigned long long (*bpf_get_smp_processor_id)(void) = (void*) BPF_FUNC_get_smp_processor_id;
static long (*bpf_get_stackid)(void* ctx, void* map, uint64_t flags) = (void*) BPF_FUNC_get_stackid;
static long (*bpf_get_current_comm)(void* buf, uint32_t buf_size) = (void*) BPF_FUNC_get_current_comm;
+static int (*bpf_trace_printk)(const char* fmt, int fmt_size, ...) = (void*) BPF_FUNC_trace_printk;
+#define bpf_printf(s, n...) bpf_trace_printk(s, sizeof(s), ## n)
+// Note: bpf only supports up to 3 arguments, log via: bpf_printf("msg %d %d %d", 1, 2, 3);
+// and read via the blocking: sudo cat /sys/kernel/debug/tracing/trace_pipe
+
#define DEFINE_BPF_PROG_EXT(SECTION_NAME, prog_uid, prog_gid, the_prog, min_kv, max_kv, \
min_loader, max_loader, opt, selinux, pindir, ignore_eng, \
ignore_user, ignore_userdebug) \