[lttng-dev] [PATCH lttng-modules 1/2] Add x86-64 override for accept4 syscall

[Jérémie Galarneau]

This patch adds an instrumentation override for the accept4() syscall
which is almost identical to accept(), except for an additional
"flags" parameter.

A follow-up patch refactors both overrides to minimize code
duplication as is done for the select/pselect6 overrides.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau at efficios.com>
---
 .../x86-64-syscalls-3.10.0-rc7_pointers_override.h | 57 ++++++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/instrumentation/syscalls/headers/x86-64-syscalls-3.10.0-rc7_pointers_override.h b/instrumentation/syscalls/headers/x86-64-syscalls-3.10.0-rc7_pointers_override.h
index 40fa930..6c59790 100644
--- a/instrumentation/syscalls/headers/x86-64-syscalls-3.10.0-rc7_pointers_override.h
+++ b/instrumentation/syscalls/headers/x86-64-syscalls-3.10.0-rc7_pointers_override.h
@@ -108,6 +108,63 @@ SC_LTTNG_TRACEPOINT_EVENT_CODE(accept,
 	TP_code_post()
 )
 
+#define OVERRIDE_64_accept4
+SC_LTTNG_TRACEPOINT_EVENT_CODE(accept4,
+	TP_PROTO(sc_exit(long ret,) int fd, struct sockaddr * upeer_sockaddr, int * upeer_addrlen, int flags),
+	TP_ARGS(sc_exit(ret,) fd, upeer_sockaddr, upeer_addrlen, flags),
+	TP_locvar(
+		__typeof__(upeer_sockaddr->sa_family) sa_family;
+		uint16_t sport;
+		uint32_t v4addr;
+		uint16_t v6addr[8];
+		int v4addr_len, v6addr_len;
+		int uaddr_len;
+	),
+	TP_code_pre(
+		sc_inout(
+			memset(tp_locvar, 0, sizeof(*tp_locvar));
+			(void) get_user(tp_locvar->uaddr_len, upeer_addrlen);
+		)
+		sc_out(
+			if (tp_locvar->uaddr_len < sizeof(struct sockaddr))
+				goto skip_code;
+			(void) get_user(tp_locvar->sa_family, &upeer_sockaddr->sa_family);
+			switch (tp_locvar->sa_family) {
+			case AF_INET:
+				if (tp_locvar->uaddr_len < sizeof(struct sockaddr_in))
+					goto skip_code;
+				(void) get_user(tp_locvar->sport, &((struct sockaddr_in *) upeer_sockaddr)->sin_port);
+				(void) get_user(tp_locvar->v4addr, &((struct sockaddr_in *) upeer_sockaddr)->sin_addr.s_addr);
+				tp_locvar->v4addr_len = 4;
+				break;
+			case AF_INET6:
+				if (tp_locvar->uaddr_len < sizeof(struct sockaddr_in6))
+					goto skip_code;
+				(void) get_user(tp_locvar->sport, &((struct sockaddr_in6 *) upeer_sockaddr)->sin6_port);
+				if (copy_from_user(tp_locvar->v6addr,
+						&((struct sockaddr_in6 *) upeer_sockaddr)->sin6_addr.in6_u.u6_addr8,
+						sizeof(tp_locvar->v6addr)))
+					memset(tp_locvar->v6addr, 0, sizeof(tp_locvar->v6addr));
+				tp_locvar->v6addr_len = 8;
+				break;
+			}
+		skip_code:
+		)
+	),
+	TP_FIELDS(
+		sc_exit(ctf_integer(long, ret, ret))
+		sc_in(ctf_integer(int, fd, fd))
+		sc_in(ctf_integer_hex(struct sockaddr *, upeer_sockaddr, upeer_sockaddr))
+		sc_inout(ctf_integer(int, upeer_addrlen, tp_locvar->uaddr_len))
+		sc_in(ctf_integer_hex(int, flags, flags))
+		sc_out(ctf_integer(int, family, tp_locvar->sa_family))
+		sc_out(ctf_integer_network(uint16_t, sport, tp_locvar->sport))
+		sc_out(ctf_sequence_network(uint8_t, v4addr, &tp_locvar->v4addr, unsigned int, tp_locvar->v4addr_len))
+		sc_out(ctf_sequence_network(uint16_t, v6addr, &tp_locvar->v6addr, unsigned int, tp_locvar->v6addr_len))
+	),
+	TP_code_post()
+)
+
 #define OVERRIDE_64_pipe
 SC_LTTNG_TRACEPOINT_EVENT(pipe,
 	TP_PROTO(sc_exit(long ret,) int * fildes),
-- 
2.9.3