[PATCH 020/107] perf trace beauty: Beautify 'sendto's sockaddr arg

Arnaldo Carvalho de Melo
2019-07-30T02:57:23Z

From: Arnaldo Carvalho de Melo <acme@redhat.com>

By just writing the collector in the augmented_raw_syscalls.c BPF
program:

# perf trace -e sendto
<SNIP>
ping/23492 sendto(3, 0x56253bbef700, 64, NONE, { .family: PF_INET, port: 0, addr: 10.10.161.32 }, 0x10) = 64
ping/23492 sendto(3, 0x56253bbef700, 64, NONE, { .family: PF_INET, port: 0, addr: 10.10.161.32 }, 0x10) = 64
ping/23492 sendto(3, 0x56253bbef700, 64, NONE, { .family: PF_INET, port: 0, addr: 10.10.161.32 }, 0x10) = 64
ping/23492 sendto(3, 0x56253bbef700, 64, NONE, { .family: PF_INET, port: 0, addr: 10.10.161.32 }, 0x10) = 64
Socket Thread/3573 sendto(247, 0x7fb32d49c000, 120, NONE, { .family: PF_UNSPEC }, NULL) = 120
DNS Res~er #18/11374 sendto(242, 0x7fb342cfe420, 20, NONE, { .family: PF_NETLINK }, 0xc) = 20
DNS Res~er #18/11374 sendto(242, 0x7fb342cfcca0, 42, MSG_NOSIGNAL, { .family: PF_UNSPEC }, NULL) = 42
DNS Res~er #18/11374 sendto(242, 0x7fb342cfcccc, 42, MSG_NOSIGNAL, { .family: PF_UNSPEC }, NULL) = 42
ping/23492 sendto(3, 0x56253bbef700, 64, NONE, { .family: PF_INET, port: 0, addr: 10.10.161.32 }, 0x10) = 64
Socket Thread/3573 sendto(242, 0x7fb308bb1c08, 296, NONE, { .family: PF_UNSPEC }, NULL) = 296
ping/23492 sendto(3, 0x56253bbef700, 64, NONE, { .family: PF_INET, port: 0, addr: 10.10.161.32 }, 0x10) = 64
ping/23492 sendto(3, 0x56253bbef700, 64, NONE, { .family: PF_INET, port: 0, addr: 10.10.161.32 }, 0x10) = 64
ping/23492 sendto(3, 0x56253bbef700, 64, NONE, { .family: PF_INET, port: 0, addr: 10.10.161.32 }, 0x10) = 64
ping/23492 sendto(3, 0x56253bbef700, 64, NONE, { .family: PF_INET, port: 0, addr: 10.10.161.32 }, 0x10) = 64
^C
#

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-p0l0rlvq19v5zf8qc2x2itow@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
.../examples/bpf/augmented_raw_syscalls.c | 21 +++++++++++++++++++
1 file changed, 21 insertions(+)

diff --git a/tools/perf/examples/bpf/augmented_raw_syscalls.c b/tools/perf/examples/bpf/augmented_raw_syscalls.c
index d7a292d7ee2f..9c2228b01ee6 100644
--- a/tools/perf/examples/bpf/augmented_raw_syscalls.c
+++ b/tools/perf/examples/bpf/augmented_raw_syscalls.c
@@ -142,6 +142,27 @@ int sys_enter_connect(struct syscall_enter_args *args)
return perf_event_output(args, &__augmented_syscalls__, BPF_F_CURRENT_CPU, augmented_args, len + socklen);
}

+SEC("!syscalls:sys_enter_sendto")
+int sys_enter_sendto(struct syscall_enter_args *args)
+{
+ int key = 0;
+ struct augmented_args_payload *augmented_args = bpf_map_lookup_elem(&augmented_args_tmp, &key);
+ const void *sockaddr_arg = (const void *)args->args[4];
+ unsigned int socklen = args->args[5];
+ unsigned int len = sizeof(augmented_args->args);
+
+ if (augmented_args == NULL)
+ return 1; /* Failure: don't filter */
+
+ if (socklen > sizeof(augmented_args->saddr))
+ socklen = sizeof(augmented_args->saddr);
+
+ probe_read(&augmented_args->saddr, socklen, sockaddr_arg);
+
+ /* If perf_event_output fails, return non-zero so that it gets recorded unaugmented */
+ return perf_event_output(args, &__augmented_syscalls__, BPF_F_CURRENT_CPU, augmented_args, len + socklen);
+}
+
SEC("!syscalls:sys_enter_open")
int sys_enter_open(struct syscall_enter_args *args)
{
--
2.21.0