From: Julien Desfossez Date: Sat, 30 Apr 2016 15:09:30 +0000 (-0400) Subject: Extract the payload of epoll_wait/epoll_pwait X-Git-Tag: v2.9.0-rc1~69 X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=f22697caff66036a134afa017980999caf02f938;p=lttng-modules.git Extract the payload of epoll_wait/epoll_pwait 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 Signed-off-by: Mathieu Desnoyers --- diff --git a/instrumentation/syscalls/headers/syscalls_pointers_override.h b/instrumentation/syscalls/headers/syscalls_pointers_override.h index 97ea9a5c..dd6f9544 100644 --- a/instrumentation/syscalls/headers/syscalls_pointers_override.h +++ b/instrumentation/syscalls/headers/syscalls_pointers_override.h @@ -693,4 +693,183 @@ 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 */