From mboxrd@z Thu Jan 1 00:00:00 1970 From: mathieu.desnoyers@efficios.com (Mathieu Desnoyers) Date: Sat, 30 Apr 2016 14:14:27 +0000 (UTC) Subject: [lttng-dev] [PATCH lttng-modules v6 3/5] Extract the FDs and flags from poll and ppoll In-Reply-To: <1461970404-27468-4-git-send-email-jdesfossez@efficios.com> References: <1461970404-27468-1-git-send-email-jdesfossez@efficios.com> <1461970404-27468-4-git-send-email-jdesfossez@efficios.com> Message-ID: <1610129397.74686.1462025667383.JavaMail.zimbra@efficios.com> ----- On Apr 29, 2016, at 6:53 PM, Julien Desfossez jdesfossez at efficios.com wrote: > Instead of printing the pointer address of the poll set, extract all the > FDs and flags from the poll set. For now, we only output the > standardized set of events to limit the verbosity of the output, we also > extract the raw value. When we switch to CTF2 we will be able to hide > unset fields and then we will extract all the fields. > > Here is an example of output with one FD: > syscall_entry_poll: { > timeout_msecs = -1, nfds = 1, fds_length = 1, > fds = [ > [0] = { fd = 4, raw_events = 0x5, events = { POLLIN = 1, POLLPRI = 0, > POLLOUT = 1, POLLERR = 0, POLLHUP = 0, padding = 0 } } ] > } > > syscall_exit_poll: { > ret = 1, nfds = 1, fds_length = 1, > fds = [ [0] = { fd = 4, raw_events = 0x4, events = { POLLIN = 0, > POLLPRI = 0, POLLOUT = 1, POLLERR = 0, POLLHUP = 0, padding = 0 } } ] } > > Signed-off-by: Julien Desfossez > --- > .../syscalls/headers/syscalls_pointers_override.h | 254 +++++++++++++++++++++ > 1 file changed, 254 insertions(+) > > diff --git a/instrumentation/syscalls/headers/syscalls_pointers_override.h > b/instrumentation/syscalls/headers/syscalls_pointers_override.h > index b9dd54a..11d5f3d 100644 > --- a/instrumentation/syscalls/headers/syscalls_pointers_override.h > +++ b/instrumentation/syscalls/headers/syscalls_pointers_override.h > @@ -301,4 +301,258 @@ SC_LTTNG_TRACEPOINT_EVENT_CODE(pselect6, > ) > #endif /* defined(CONFIG_X86_32) || defined(CONFIG_X86_64) || > defined(CONFIG_ARM64) || defined(CONFIG_ARM) */ > > +#ifndef ONCE_LTTNG_TRACE_POLL_H > +#define ONCE_LTTNG_TRACE_POLL_H > + > +#define LTTNG_POLL_NRFLAGS (POLLNVAL + 1) > +#define POLL_FLAGS_PADDING_SIZE (sizeof(uint8_t) * BITS_PER_BYTE) - \ > + ilog2(LTTNG_POLL_NRFLAGS - 1) > + > +/* > + * Only extract the values specified by iBCS2 for now. > + */ > +static struct lttng_event_field lttng_pollfd_flag_fields[] = { > + [ilog2(POLLIN)] = { > + .name = "POLLIN", > + .type = __type_integer(int, 1, 1, 0, __LITTLE_ENDIAN, 10, none), > + }, > + [ilog2(POLLPRI)] = { > + .name = "POLLPRI", > + .type = __type_integer(int, 1, 1, 0, __LITTLE_ENDIAN, 10, none), > + }, > + [ilog2(POLLOUT)] = { > + .name = "POLLOUT", > + .type = __type_integer(int, 1, 1, 0, __LITTLE_ENDIAN, 10, none), > + }, > + [ilog2(POLLERR)] = { > + .name = "POLLERR", > + .type = __type_integer(int, 1, 1, 0, __LITTLE_ENDIAN, 10, none), > + }, > + [ilog2(POLLHUP)] = { > + .name = "POLLHUP", > + .type = __type_integer(int, 1, 1, 0, __LITTLE_ENDIAN, 10, none), > + }, > + [ilog2(POLLNVAL)] = { > + .name = "POLLNVAL", > + .type = __type_integer(int, 1, 1, 0, __LITTLE_ENDIAN, 10, none), > + }, > + [ilog2(LTTNG_POLL_NRFLAGS)] = { > + .name = "padding", > + .type = __type_integer(int, POLL_FLAGS_PADDING_SIZE, 1, 0, > + __LITTLE_ENDIAN, 10, none), > + }, > +}; > + > +static struct lttng_event_field lttng_pollfd_fields[] = { > + [0] = { > + .name = "fd", > + .type = __type_integer(int, 0, 0, 0, __BYTE_ORDER, 10, none), > + }, > + [1] = { > + .name = "raw_events", > + .type = __type_integer(short, 0, 0, 0, __BYTE_ORDER, 16, none), > + }, > + [2] = { > + .name = "events", > + .type = { > + .atype = atype_struct, > + .u._struct.nr_fields = ARRAY_SIZE(lttng_pollfd_flag_fields), > + .u._struct.fields = lttng_pollfd_flag_fields, > + } > + }, > +}; > + > +static struct lttng_type lttng_pollfd_elem = { > + .atype = atype_struct, > + .u._struct.nr_fields = ARRAY_SIZE(lttng_pollfd_fields), > + .u._struct.fields = lttng_pollfd_fields, > +}; > +#endif /* ONCE_LTTNG_TRACE_POLL_H */ > + > +#define LTTNG_SYSCALL_POLL_locvar \ > + unsigned int fds_length, fds_max_len, alloc_fds; \ > + struct pollfd *fds; \ > + uint8_t overflow; > + > +#define LTTNG_SYSCALL_POLL_code_pre \ > + BUILD_BUG_ON(((ARRAY_SIZE(lttng_pollfd_flag_fields) - 1) + \ > + POLL_FLAGS_PADDING_SIZE) != \ > + sizeof(uint8_t) * BITS_PER_BYTE); \ > + tp_locvar->fds = NULL; \ > + tp_locvar->overflow = 0; \ > + \ > + sc_in( \ > + if (nfds * sizeof(struct pollfd) > PAGE_SIZE) { \ This check is incorrect if nfds * sizeof(struct pollfd) overflows an unsigned int. Should instead be: if (nfds > PAGE_SIZE / sizeof(struct pollfd)) Please audit all other checks on input size for this kind of mistake. > + tp_locvar->fds_length = PAGE_SIZE / sizeof(struct pollfd); \ > + tp_locvar->fds_max_len = PAGE_SIZE / sizeof(struct pollfd); \ > + tp_locvar->overflow = 1; \ > + } else { \ > + tp_locvar->fds_length = nfds; \ > + tp_locvar->fds_max_len = nfds; \ > + } \ > + tp_locvar->alloc_fds = tp_locvar->fds_length * sizeof(struct pollfd); \ > + ) \ > + /* \ > + * On exit, the number of active FDs is determined by ret, \ > + * nfds stays the same as the entry, but we only want to \ > + * output the FDs that are relevant. \ > + */ \ > + sc_out( \ > + if (ret <= 0 || ret > nfds) \ > + goto error; \ > + \ > + if (nfds * sizeof(struct pollfd) > PAGE_SIZE) { \ same here. Thanks, Mathieu > + tp_locvar->fds_length = PAGE_SIZE / sizeof(struct pollfd); \ > + tp_locvar->fds_max_len = PAGE_SIZE / sizeof(struct pollfd); \ > + tp_locvar->overflow = 1; \ > + } else { \ > + tp_locvar->fds_length = ret; \ > + tp_locvar->fds_max_len = nfds; \ > + } \ > + tp_locvar->alloc_fds = tp_locvar->fds_max_len * sizeof(struct pollfd); \ > + ) \ > + { \ > + int err; \ > + \ > + tp_locvar->fds = kmalloc(tp_locvar->alloc_fds, \ > + GFP_ATOMIC | GFP_NOWAIT); \ > + if (!tp_locvar->fds) \ > + goto error; \ > + err = lib_ring_buffer_copy_from_user_check_nofault( \ > + tp_locvar->fds, ufds, \ > + nfds * sizeof(struct pollfd)); \ > + if (err != 0) \ > + goto error; \ > + } \ > + goto end; \ > + \ > +error: \ > + tp_locvar->fds_length = 0; \ > + tp_locvar->fds_max_len = 0; \ > +end: \ > + ; > + > +#define LTTNG_SYSCALL_POLL_fds_field \ > + sc_in( \ > + ctf_custom_field( \ > + ctf_custom_type( \ > + .atype = atype_sequence_compound, \ > + .u.sequence_compound.length_name = "fds_length", \ > + .u.sequence_compound.elem_type = <tng_pollfd_elem, \ > + ), \ > + fds, \ > + ctf_custom_code( \ > + uint32_t i; \ > + \ > + ctf_align(int) /* Align on largest field in struct. */ \ > + for (i = 0; i < tp_locvar->fds_length; i++) { \ > + ctf_integer_type(int, tp_locvar->fds[i].fd) \ > + ctf_integer_type(short, tp_locvar->fds[i].events) \ > + ctf_integer_bitfield_type(uint8_t, \ > + (uint8_t) tp_locvar->fds[i].events) \ > + } \ > + ) \ > + ) \ > + ) \ > + sc_out( \ > + ctf_custom_field( \ > + ctf_custom_type( \ > + .atype = atype_sequence_compound, \ > + .u.sequence_compound.length_name = "fds_length", \ > + .u.sequence_compound.elem_type = <tng_pollfd_elem, \ > + ), \ > + fds, \ > + ctf_custom_code( \ > + uint32_t i; \ > + unsigned int nr = 0; \ > + \ > + ctf_align(int) /* Align on largest field in struct. */ \ > + /* \ > + * Iterate over the complete array, but only output \ > + * "ret" active FDs. \ > + */ \ > + for (i = 0; i < tp_locvar->fds_max_len; i++) { \ > + if (!tp_locvar->fds[i].revents) \ > + continue; \ > + if (nr++ >= tp_locvar->fds_length) \ > + break; \ > + ctf_integer_type(int, tp_locvar->fds[i].fd) \ > + ctf_integer_type(short, tp_locvar->fds[i].revents) \ > + ctf_integer_bitfield_type(uint8_t, \ > + (uint8_t) tp_locvar->fds[i].revents) \ > + } \ > + /* \ > + * If there is a discrepancy between ret and the \ > + * content of revents (e.g. caused by userspace corrupting \ > + * the array from a concurrent thread), we have to output \ > + * zeros to keep the trace readable. \ > + */ \ > + for (i = nr; i < tp_locvar->fds_length; i++) { \ > + ctf_integer_type(int, 0) \ > + ctf_integer_type(short, 0) \ > + ctf_integer_bitfield_type(uint8_t, 0) \ > + } \ > + ) \ > + ) \ > + ) > + > +#define LTTNG_SYSCALL_POLL_code_post \ > + kfree(tp_locvar->fds); > + > +#if defined(CONFIG_X86_32) || defined(CONFIG_X86_64) > +#define OVERRIDE_32_poll > +#define OVERRIDE_64_poll > +SC_LTTNG_TRACEPOINT_EVENT_CODE(poll, > + TP_PROTO(sc_exit(long ret,) struct pollfd __user * ufds, > + unsigned int nfds, int timeout_msecs), > + TP_ARGS(sc_exit(ret,) ufds, nfds, timeout_msecs), > + TP_locvar( > + LTTNG_SYSCALL_POLL_locvar > + ), > + TP_code_pre( > + LTTNG_SYSCALL_POLL_code_pre > + ), > + TP_FIELDS( > + sc_exit(ctf_integer(long, ret, ret)) > + sc_in(ctf_integer(int, timeout_msecs, timeout_msecs)) > + sc_inout(ctf_integer(unsigned int, nfds, nfds)) > + sc_inout(ctf_integer(unsigned int, fds_length, tp_locvar->fds_length)) > + sc_in(ctf_integer(uint8_t, overflow, tp_locvar->overflow)) > + LTTNG_SYSCALL_POLL_fds_field > + ), > + TP_code_post( > + LTTNG_SYSCALL_POLL_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_ppoll > +#define OVERRIDE_64_ppoll > +SC_LTTNG_TRACEPOINT_EVENT_CODE(ppoll, > + TP_PROTO(sc_exit(long ret,) struct pollfd __user * ufds, > + unsigned int nfds, struct timespec * tsp, const sigset_t * sigmask, size_t > sigsetsize), > + TP_ARGS(sc_exit(ret,) ufds, nfds, tsp, sigmask, sigsetsize), > + TP_locvar( > + LTTNG_SYSCALL_POLL_locvar > + ), > + TP_code_pre( > + LTTNG_SYSCALL_POLL_code_pre > + ), > + TP_FIELDS( > + sc_exit(ctf_integer(long, ret, ret)) > + sc_in(ctf_integer(struct timespec *, tsp, tsp)) > + sc_in(ctf_integer(const sigset_t *, sigmask, sigmask)) > + sc_in(ctf_integer(size_t, sigsetsize, sigsetsize)) > + sc_inout(ctf_integer(unsigned int, nfds, nfds)) > + sc_inout(ctf_integer(unsigned int, fds_length, tp_locvar->fds_length)) > + sc_inout(ctf_integer(uint8_t, overflow, tp_locvar->overflow)) > + LTTNG_SYSCALL_POLL_fds_field > + ), > + TP_code_post( > + LTTNG_SYSCALL_POLL_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