[lttng-dev] [PATCH lttng-modules v7 5/5] Extract the payload of epoll_wait/epoll_pwait
Julien Desfossez
jdesfossez at efficios.com
Sat Apr 30 15:09:30 UTC 2016
When epoll_wait returns, extract the content of the "events" field
(events set and data payload).
Here is an example output:
syscall_entry_epoll_wait: { epfd = 3, maxevents = 32, timeout = 100 }
syscall_exit_epoll_wait: { ret = 1, fds_length = 1,
fds = [ [0] = { raw_events = 0x1,
events = { EPOLLIN = 1, EPOLLPRI = 0, EPOLLOUT = 0, EPOLLERR = 0,
padding = 0 },
data_union = { u64 = 0x100000005, fd = 5 } } ]
}
Signed-off-by: Julien Desfossez <jdesfossez at efficios.com>
---
.../syscalls/headers/syscalls_pointers_override.h | 179 +++++++++++++++++++++
1 file changed, 179 insertions(+)
diff --git a/instrumentation/syscalls/headers/syscalls_pointers_override.h b/instrumentation/syscalls/headers/syscalls_pointers_override.h
index 636287f..5be739b 100644
--- a/instrumentation/syscalls/headers/syscalls_pointers_override.h
+++ b/instrumentation/syscalls/headers/syscalls_pointers_override.h
@@ -695,4 +695,183 @@ SC_LTTNG_TRACEPOINT_EVENT_CODE(epoll_ctl,
)
#endif /* defined(CONFIG_X86_32) || defined(CONFIG_X86_64) || defined(CONFIG_ARM64) || defined(CONFIG_ARM) */
+#ifndef ONCE_LTTNG_TRACE_EPOLL_H
+#define ONCE_LTTNG_TRACE_EPOLL_H
+
+static struct lttng_event_field lttng_epoll_wait_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,
+ }
+ },
+};
+
+static struct lttng_type lttng_epoll_wait_elem = {
+ .atype = atype_struct,
+ .u._struct.nr_fields = ARRAY_SIZE(lttng_epoll_wait_fields),
+ .u._struct.fields = lttng_epoll_wait_fields,
+};
+
+#endif /* ONCE_LTTNG_TRACE_EPOLL_H */
+
+#define LTTNG_SYSCALL_EPOLL_WAIT_locvar \
+ sc_out( \
+ unsigned int fds_length; \
+ uint8_t overflow; \
+ struct epoll_event *events; \
+ )
+
+#define LTTNG_SYSCALL_EPOLL_WAIT_code_pre \
+ BUILD_BUG_ON(((ARRAY_SIZE(lttng_epoll_ctl_events_fields) - 1) + \
+ EPOLL_FLAGS_PADDING_SIZE) != \
+ sizeof(uint8_t) * BITS_PER_BYTE); \
+ sc_out({ \
+ int err; \
+ unsigned long maxalloc; \
+ \
+ tp_locvar->fds_length = 0; \
+ tp_locvar->events = NULL; \
+ tp_locvar->overflow = 0; \
+ \
+ if (maxevents <= 0 || ret <= 0 || ret > maxevents) \
+ goto skip_code; \
+ \
+ if (maxevents > (PAGE_SIZE / sizeof(struct epoll_event))) { \
+ maxalloc = PAGE_SIZE / sizeof(struct epoll_event); \
+ } else { \
+ maxalloc = maxevents; \
+ } \
+ \
+ if (ret > maxalloc) { \
+ tp_locvar->fds_length = maxalloc; \
+ tp_locvar->overflow = 1; \
+ } else { \
+ tp_locvar->fds_length = ret; \
+ } \
+ \
+ tp_locvar->events = kmalloc( \
+ maxalloc * sizeof(struct epoll_event), \
+ GFP_ATOMIC | GFP_NOWAIT); \
+ if (!tp_locvar->events) { \
+ tp_locvar->fds_length = 0; \
+ goto skip_code; \
+ } \
+ \
+ err = lib_ring_buffer_copy_from_user_check_nofault( \
+ tp_locvar->events, uevents, \
+ maxevents * sizeof(struct epoll_event)); \
+ if (err != 0) \
+ tp_locvar->fds_length = 0; \
+ } \
+ skip_code: \
+ )
+
+#define LTTNG_SYSCALL_EPOLL_WAIT_fds_field \
+ ctf_custom_field( \
+ ctf_custom_type( \
+ .atype = atype_sequence_compound, \
+ .u.sequence_compound.length_name = \
+ "fds_length", \
+ .u.sequence_compound.elem_type = \
+ <tng_epoll_wait_elem, \
+ ), \
+ fds, \
+ ctf_custom_code( \
+ uint32_t i; \
+ \
+ ctf_align(uint64_t) \
+ for (i = 0; i < tp_locvar->fds_length; i++) { \
+ ctf_integer_type(uint64_t, tp_locvar->events[i].data) \
+ ctf_integer_type(int, tp_locvar->events[i].data) \
+ ctf_integer_bitfield_type(uint32_t, \
+ tp_locvar->events[i].events) \
+ ctf_integer_bitfield_type(uint8_t, \
+ (uint8_t) tp_locvar->events[i].events) \
+ } \
+ ) \
+ )
+
+#define LTTNG_SYSCALL_EPOLL_WAIT_code_post \
+ sc_out( \
+ kfree(tp_locvar->events); \
+ )
+
+
+#if defined(CONFIG_X86_32) || defined(CONFIG_X86_64)
+#define OVERRIDE_32_epoll_wait
+#define OVERRIDE_64_epoll_wait
+SC_LTTNG_TRACEPOINT_EVENT_CODE(epoll_wait,
+ TP_PROTO(sc_exit(long ret,) int epfd, struct epoll_event __user * uevents,
+ int maxevents, int timeout),
+ TP_ARGS(sc_exit(ret,) epfd, uevents, maxevents, timeout),
+ TP_locvar(
+ LTTNG_SYSCALL_EPOLL_WAIT_locvar
+ ),
+ TP_code_pre(
+ LTTNG_SYSCALL_EPOLL_WAIT_code_pre
+ ),
+ TP_FIELDS(
+ sc_exit(ctf_integer(long, ret, ret))
+ sc_in(ctf_integer(int, epfd, epfd))
+ sc_in(ctf_integer(int, maxevents, maxevents))
+ sc_in(ctf_integer(int, timeout, timeout))
+ sc_out(ctf_integer(unsigned int, fds_length, tp_locvar->fds_length))
+ sc_out(ctf_integer(uint8_t, overflow, tp_locvar->overflow))
+ sc_out(
+ LTTNG_SYSCALL_EPOLL_WAIT_fds_field
+ )
+ ),
+ TP_code_post(
+ LTTNG_SYSCALL_EPOLL_WAIT_code_post
+ )
+)
+#endif /* defined(CONFIG_X86_32) || defined(CONFIG_X86_64) */
+
+#if defined(CONFIG_X86_32) || defined(CONFIG_X86_64) || defined(CONFIG_ARM64) || defined(CONFIG_ARM)
+#define OVERRIDE_32_epoll_pwait
+#define OVERRIDE_64_epoll_pwait
+SC_LTTNG_TRACEPOINT_EVENT_CODE(epoll_pwait,
+ TP_PROTO(sc_exit(long ret,) int epfd, struct epoll_event __user * uevents,
+ int maxevents, int timeout, const sigset_t __user * sigmask, size_t sigsetsize),
+ TP_ARGS(sc_exit(ret,) epfd, uevents, maxevents, timeout, sigmask, sigsetsize),
+ TP_locvar(
+ LTTNG_SYSCALL_EPOLL_WAIT_locvar
+ ),
+ TP_code_pre(
+ LTTNG_SYSCALL_EPOLL_WAIT_code_pre
+ ),
+ TP_FIELDS(
+ sc_exit(ctf_integer(long, ret, ret))
+ sc_in(ctf_integer(int, epfd, epfd))
+ sc_in(ctf_integer(int, maxevents, maxevents))
+ sc_in(ctf_integer(int, timeout, timeout))
+ sc_in(ctf_integer_hex(const sigset_t *, sigmask, sigmask))
+ sc_in(ctf_integer(size_t, sigsetsize, sigsetsize))
+ sc_out(ctf_integer(unsigned int, fds_length, tp_locvar->fds_length))
+ sc_out(ctf_integer(uint8_t, overflow, tp_locvar->overflow))
+ sc_out(
+ LTTNG_SYSCALL_EPOLL_WAIT_fds_field
+ )
+ ),
+ TP_code_post(
+ LTTNG_SYSCALL_EPOLL_WAIT_code_post
+ )
+)
+#endif /* defined(CONFIG_X86_32) || defined(CONFIG_X86_64) || defined(CONFIG_ARM64) || defined(CONFIG_ARM) */
+
#endif /* CREATE_SYSCALL_TABLE */
--
1.9.1
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