fix(userspace/libsinsp): avoid setting evt fdinfo in fch* parsers

Setting the event's fdinfo by leveraging the event's fd parameter is
already done in `sinsp_parser::reset()` and can be avoided the
`fchmod/fchown` exit event parsers. This means completely remove this
parsers.

Signed-off-by: Leonardo Di Giovanna <[email protected]>

Author: ekoops

userspace/libsinsp/parsers.cpp

@@ -140,10 +140,6 @@ void sinsp_parser::process_event(sinsp_evt &evt, sinsp_parser_verdict &verdict)
 	case PPME_SYSCALL_OPEN_BY_HANDLE_AT_X:
 		parse_open_openat_creat_exit(evt);
 		break;
-	case PPME_SYSCALL_FCHMOD_X:
-	case PPME_SYSCALL_FCHOWN_X:
-		parse_fchmod_fchown_exit(evt);
-		break;
 	case PPME_SYSCALL_UNSHARE_X:
 	case PPME_SYSCALL_SETNS_X:
 		parse_unshare_setns_exit(evt);
@@ -2050,20 +2046,6 @@ void sinsp_parser::parse_open_openat_creat_exit(sinsp_evt &evt) const {
 	}
 }
 
-void sinsp_parser::parse_fchmod_fchown_exit(sinsp_evt &evt) {
-	// Both of these syscalls act on fds although they do not
-	// create them. Take the fd argument and attempt to look up
-	// the fd from the thread.
-	if(evt.get_tinfo() == nullptr) {
-		return;
-	}
-
-	ASSERT(evt.get_param_info(1)->type == PT_FD);
-	const int64_t fd = evt.get_param(1)->as<int64_t>();
-	evt.get_tinfo()->m_lastevent_fd = fd;
-	evt.set_fd_info(evt.get_tinfo()->get_fd(fd));
-}
-
 //
 // Helper function to allocate a socket fd, initialize it by parsing its parameters and add it to
 // the fd table of the given thread.

userspace/libsinsp/parsers.h

@@ -91,7 +91,6 @@ class sinsp_parser {
 	void parse_clone_exit(sinsp_evt& evt, sinsp_parser_verdict& verdict) const;
 	void parse_execve_exit(sinsp_evt& evt, sinsp_parser_verdict& verdict) const;
 	void parse_open_openat_creat_exit(sinsp_evt& evt) const;
-	static void parse_fchmod_fchown_exit(sinsp_evt& evt);
 	void parse_pipe_exit(sinsp_evt& evt) const;
 	void parse_socketpair_exit(sinsp_evt& evt) const;
 	void parse_socket_exit(sinsp_evt& evt) const;