perf trace augmented_syscalls: Augment sendto's 'addr' arg

Its a 'struct sockaddr' pointer, augment it with the same beautifier as
for 'connect' and 'bind', that all receive from userspace that pointer.

Doing it in the other direction remains to be done, hooking at the
syscalls:sys_exit_{accept4?,recvmsg} tracepoints somehow.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-k2eu68lsphnm2fthc32gq76c@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-trace.c

@@ -795,7 +795,8 @@ static struct syscall_fmt {
 	{ .name	    = "sendmsg",
 	  .arg = { [2] = { .scnprintf = SCA_MSG_FLAGS, /* flags */ }, }, },
 	{ .name	    = "sendto",
-	  .arg = { [3] = { .scnprintf = SCA_MSG_FLAGS, /* flags */ }, }, },
+	  .arg = { [3] = { .scnprintf = SCA_MSG_FLAGS, /* flags */ },
+		   [4] = { .scnprintf = SCA_SOCKADDR, /* addr */ }, }, },
 	{ .name	    = "set_tid_address", .errpid = true, },
 	{ .name	    = "setitimer",
 	  .arg = { [0] = STRARRAY(which, itimers), }, },

tools/perf/examples/bpf/augmented_syscalls.c

@@ -142,4 +142,17 @@ struct syscall_enter_connect_args {
 
 augmented_sockaddr_syscall_enter(connect);
 
+struct syscall_enter_sendto_args {
+	unsigned long long common_tp_fields;
+	long		   syscall_nr;
+	long		   fd;
+	void		   *buff;
+	long		   len;
+	unsigned long	   flags;
+	struct sockaddr	   *addr_ptr;
+	long		   addr_len;
+};
+
+augmented_sockaddr_syscall_enter(sendto);
+
 license(GPL);