From mboxrd@z Thu Jan 1 00:00:00 1970 From: mathieu.desnoyers@efficios.com (Mathieu Desnoyers) Date: Sat, 30 Apr 2016 14:22:22 +0000 (UTC) Subject: [lttng-dev] [PATCH lttng-modules v6 5/5] Extract the payload of epoll_wait/epoll_pwait In-Reply-To: <1461970404-27468-6-git-send-email-jdesfossez@efficios.com> References: <1461970404-27468-1-git-send-email-jdesfossez@efficios.com> <1461970404-27468-6-git-send-email-jdesfossez@efficios.com> Message-ID: <1608828304.74707.1462026142059.JavaMail.zimbra@efficios.com> ----- On Apr 29, 2016, at 6:53 PM, Julien Desfossez jdesfossez at efficios.com wrote: > 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 > --- > .../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 59931df..ceb1fab 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 * sizeof(struct epoll_event)) > PAGE_SIZE) { \ change for if (maxevents > PAGE_SIZE / sizeof(struct epoll_event)) to handle overflows. > + 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, \ > + cpu_to_le32(tp_locvar->events[i].events)) \ why LE, and why 32-bit rather than 16 ? Thanks, Mathieu > + 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 -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com