Extract the FDs and flags from poll and ppoll
[lttng-modules.git] / instrumentation / syscalls / headers / syscalls_pointers_override.h
index d116052fbfeca19973712c5a179fb4040b004f74..1a2695e197ba2ae952942f7f206a6f2e780956fb 100644 (file)
@@ -300,4 +300,257 @@ 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 > PAGE_SIZE / sizeof(struct pollfd)) {                         \
+                       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 > PAGE_SIZE / sizeof(struct pollfd)) {                         \
+                       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 = &lttng_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 = &lttng_pollfd_elem,            \
+                       ),                                                                      \
+                       fds,                                                                    \
+                       ctf_custom_code(                                                        \
+                               unsigned int i, 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 */
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