Use FUNC_RET_READ for inet_csk_accept (#201)

* use FUNC_RET_READ for inet_csk_accept

* add init for ret value macro

* modify probe_fill_relos

* formatting

Author: fearful-symmetry

GPL/Events/Helpers.h

@@ -113,6 +113,7 @@ const volatile int consumer_pid = 0;
         ret;                                                                                       \
     })
 
+// value is replaced later by `probe_fill_relos()`
 #define DECL_FUNC_RET(func) const volatile int ret__##func##__ = 0;
 #define FUNC_RET_READ(type, func)                                                                  \
     ({                                                                                             \

GPL/Events/Network/Probe.bpf.c

@@ -18,6 +18,8 @@
 #include "Network.h"
 #include "State.h"
 
+DECL_FUNC_RET(inet_csk_accept);
+
 static int inet_csk_accept__exit(struct sock *sk)
 {
     if (!sk)
@@ -42,9 +44,9 @@ static int inet_csk_accept__exit(struct sock *sk)
 }
 
 SEC("fexit/inet_csk_accept")
-int BPF_PROG(
-    fexit__inet_csk_accept, struct sock *sk, int flags, int *err, bool kern, struct sock *ret)
+int BPF_PROG(fexit__inet_csk_accept)
 {
+    struct sock *ret = FUNC_RET_READ(___type(ret), inet_csk_accept);
     return inet_csk_accept__exit(ret);
 }
 

non-GPL/Events/Lib/EbpfEvents.c

@@ -268,6 +268,8 @@ static int probe_fill_relos(struct btf *btf, struct EventProbe_bpf *obj)
 {
     int err = 0;
 
+    err = err ?: FILL_FUNC_RET_IDX(obj, btf, inet_csk_accept);
+
     err = err ?: FILL_FUNC_ARG_IDX(obj, btf, vfs_unlink, dentry);
     err = err ?: FILL_FUNC_RET_IDX(obj, btf, vfs_unlink);