[lttng-dev] [PATCH lttng-modules v6 4/5] Extract the payload for epoll_ctl
Mathieu Desnoyers
mathieu.desnoyers at efficios.com
Sat Apr 30 14:19:24 UTC 2016
----- On Apr 30, 2016, at 10:17 AM, Mathieu Desnoyers mathieu.desnoyers at efficios.com wrote:
> ----- On Apr 29, 2016, at 6:53 PM, Julien Desfossez jdesfossez at efficios.com
> wrote:
>
>> Map the operation to its name (EPOLL_CTL_*), extract the standard event
>> flags (EPOLL*) and output the data in two different formats: FD as an
>> int in decimal, and u64 in hex. The less standard event flags are not
>> extracted yet, but we extract the raw value in hex for more advanced
>> analyses.
>>
>> Here is an example output:
>> syscall_entry_epoll_ctl: {
>> epfd = 4, op_enum = ( "EPOLL_CTL_ADD" : container = 1 ),
>> fd = 0, event = { raw_events = 0x80000003,
>> events = { EPOLLIN = 1, EPOLLPRI = 1, EPOLLOUT = 0, EPOLLERR = 0,
>> padding = 0 },
>> data_union = { u64 = 0x0, fd = 0 } }
>> }
>>
>> syscall_exit_epoll_ctl: { ret = 0 }
>>
>> Signed-off-by: Julien Desfossez <jdesfossez at efficios.com>
>> ---
>> .../syscalls/headers/syscalls_pointers_override.h | 140 +++++++++++++++++++++
>> 1 file changed, 140 insertions(+)
>>
>> diff --git a/instrumentation/syscalls/headers/syscalls_pointers_override.h
>> b/instrumentation/syscalls/headers/syscalls_pointers_override.h
>> index 11d5f3d..59931df 100644
>> --- a/instrumentation/syscalls/headers/syscalls_pointers_override.h
>> +++ b/instrumentation/syscalls/headers/syscalls_pointers_override.h
>> @@ -555,4 +555,144 @@ SC_LTTNG_TRACEPOINT_EVENT_CODE(ppoll,
>> )
>> #endif /* defined(CONFIG_X86_32) || defined(CONFIG_X86_64) ||
>> defined(CONFIG_ARM64) || defined(CONFIG_ARM) */
>>
>> +#include <linux/eventpoll.h>
>> +
>> +SC_LTTNG_TRACEPOINT_ENUM(lttng_epoll_op,
>> + TP_ENUM_VALUES(
>> + ctf_enum_value("EPOLL_CTL_ADD", EPOLL_CTL_ADD)
>> + ctf_enum_value("EPOLL_CTL_DEL", EPOLL_CTL_DEL)
>> + ctf_enum_value("EPOLL_CTL_MOD", EPOLL_CTL_MOD)
>> + )
>> +)
>> +
>> +#ifndef ONCE_LTTNG_TRACE_EPOLL_CTL_H
>> +#define ONCE_LTTNG_TRACE_EPOLL_CTL_H
>> +
>> +#define LTTNG_EPOLL_NRFLAGS (POLLHUP + 1)
>> +#define EPOLL_FLAGS_PADDING_SIZE (sizeof(uint8_t) * BITS_PER_BYTE) - \
>> + ilog2(LTTNG_EPOLL_NRFLAGS - 1)
>> +
>> +/*
>> + * Only extract the values specified by iBCS2 for now.
>> + */
>> +static struct lttng_event_field lttng_epoll_ctl_events_fields[] = {
>> + /* 0x0001 */
>> + [ilog2(POLLIN)] = {
>> + .name = "EPOLLIN",
>> + .type = __type_integer(int, 1, 1, 0, __LITTLE_ENDIAN, 10, none),
>> + },
>> + /* 0x0002 */
>> + [ilog2(POLLPRI)] = {
>> + .name = "EPOLLPRI",
>> + .type = __type_integer(int, 1, 1, 0, __LITTLE_ENDIAN, 10, none),
>> + },
>> + /* 0x0004 */
>> + [ilog2(POLLOUT)] = {
>> + .name = "EPOLLOUT",
>> + .type = __type_integer(int, 1, 1, 0, __LITTLE_ENDIAN, 10, none),
>> + },
>> + /* 0x0008 */
>> + [ilog2(POLLERR)] = {
>> + .name = "EPOLLERR",
>> + .type = __type_integer(int, 1, 1, 0, __LITTLE_ENDIAN, 10, none),
>> + },
>> + /* 0x0010 */
>> + [ilog2(POLLHUP)] = {
>> + .name = "EPOLLHUP",
>> + .type = __type_integer(int, 1, 1, 0, __LITTLE_ENDIAN, 10, none),
>> + },
>> + [ilog2(LTTNG_EPOLL_NRFLAGS)] = {
>> + .name = "padding",
>> + .type = __type_integer(int, EPOLL_FLAGS_PADDING_SIZE, 1, 0,
>> + __LITTLE_ENDIAN, 10, none),
>> + },
>> +
>> +};
>> +
>> +static struct lttng_event_field lttng_epoll_data_fields[] = {
>> + [0] = {
>> + .name = "u64",
>> + .type = __type_integer(uint64_t, 0, 0, 0, __BYTE_ORDER, 16, none),
>> + },
>> + [1] = {
>> + .name = "fd",
>> + .type = __type_integer(int, 0, 0, 0, __BYTE_ORDER, 10, none),
>> + },
>> +};
>> +
>> +static struct lttng_event_field epoll_ctl_fields[] = {
>> + [0] = {
>> + .name = "data_union",
>> + .type = {
>> + .atype = atype_struct,
>> + .u._struct.nr_fields = ARRAY_SIZE(lttng_epoll_data_fields),
>> + .u._struct.fields = lttng_epoll_data_fields,
>> + }
>> + },
>> + [1] = {
>> + .name = "raw_events",
>> + .type = __type_integer(uint32_t, 0, 0, 0, __BYTE_ORDER, 16, none),
>> + },
>> + [2] = {
>> + .name = "events",
>> + .type = {
>> + .atype = atype_struct,
>> + .u._struct.nr_fields = ARRAY_SIZE(lttng_epoll_ctl_events_fields),
>> + .u._struct.fields = lttng_epoll_ctl_events_fields,
>> + }
>> + },
>> +};
>> +#endif /* ONCE_LTTNG_TRACE_EPOLL_CTL_H */
>> +
>> +#if defined(CONFIG_X86_32) || defined(CONFIG_X86_64) || defined(CONFIG_ARM64)
>> || defined(CONFIG_ARM)
>> +#define OVERRIDE_32_epoll_ctl
>> +#define OVERRIDE_64_epoll_ctl
>> +SC_LTTNG_TRACEPOINT_EVENT_CODE(epoll_ctl,
>> + TP_PROTO(sc_exit(long ret,) int epfd, int op, int fd,
>> + struct epoll_event __user * uevent),
>> + TP_ARGS(sc_exit(ret,) epfd, op, fd, uevent),
>> + TP_locvar(
>> + struct epoll_event event;
>> + int err;
>> + ),
>> + TP_code_pre(
>> + tp_locvar->err = lib_ring_buffer_copy_from_user_check_nofault(
>> + &tp_locvar->event, uevent, sizeof(struct epoll_event));
>> + ),
>> + TP_FIELDS(
>> + sc_exit(ctf_integer(long, ret, ret))
>> + sc_in(ctf_integer(int, epfd, epfd))
>> + sc_in(ctf_enum(lttng_epoll_op, int, op_enum, op))
>> + sc_in(ctf_integer(int, fd, fd))
>> + sc_in(
>> + ctf_custom_field(
>> + ctf_custom_type(
>> + .atype = atype_struct,
>> + .u._struct.nr_fields = ARRAY_SIZE(epoll_ctl_fields),
>> + .u._struct.fields = epoll_ctl_fields,
>> + ),
>> + event,
>> + ctf_custom_code(
>> + ctf_align(uint64_t)
>> + if (!tp_locvar->err) {
>> + ctf_integer_type(uint64_t, tp_locvar->event.data)
>> + ctf_integer_type(int, tp_locvar->event.data)
>> + ctf_integer_bitfield_type(uint32_t,
>> + cpu_to_le32(tp_locvar->event.events))
>
> not sure why we reverse the endianness here ? It does not
> match the "__BYTE_ORDER" type description, and differs from
> the way raw_events fields is handled in the poll/ppoll instrumentation.
also, why use a 32-bit integer rather than 16-bit as in poll/ppoll here ?
Mathie
>
> Thanks,
>
> Mathieu
>
>> + ctf_integer_bitfield_type(uint8_t,
>> + (uint8_t) tp_locvar->event.events)
>> + } else {
>> + ctf_integer_type(uint64_t, 0)
>> + ctf_integer_type(int, 0)
>> + ctf_integer_bitfield_type(uint32_t, 0)
>> + ctf_integer_bitfield_type(uint8_t, 0)
>> + }
>> + )
>> + )
>> + )
>> + ),
>> + TP_code_post()
>> +)
>> +#endif /* defined(CONFIG_X86_32) || defined(CONFIG_X86_64) ||
>> defined(CONFIG_ARM64) || defined(CONFIG_ARM) */
>> +
>> #endif /* CREATE_SYSCALL_TABLE */
>> --
>> 1.9.1
>
> --
> Mathieu Desnoyers
> EfficiOS Inc.
> http://www.efficios.com
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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