ltt-events.h

   1 #ifndef _LTT_EVENTS_H
   2 #define _LTT_EVENTS_H
   3
   4 /*
   5  * ltt-events.h
   6  *
   7  * Copyright 2010 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  *
   9  * Holds LTTng per-session event registry.
  10  */
  11
  12 #include <linux/list.h>
  13 #include <linux/uuid.h>
  14 #include <linux/kprobes.h>
  15 #include "ltt-debugfs-abi.h"
  16
  17 struct ltt_channel;
  18 struct ltt_session;
  19 struct lib_ring_buffer_ctx;
  20
  21 /* Type description */
  22
  23 /* Update the astract_types name table in lttng-types.c along with this enum */
  24 enum abstract_types {
  25         atype_integer,
  26         atype_enum,
  27         atype_array,
  28         atype_sequence,
  29         atype_string,
  30         NR_ABSTRACT_TYPES,
  31 };
  32
  33 /* Update the string_encodings name table in lttng-types.c along with this enum */
  34 enum lttng_string_encodings {
  35         lttng_encode_UTF8 = 0,
  36         lttng_encode_ASCII = 1,
  37         NR_STRING_ENCODINGS,
  38 };
  39
  40 struct lttng_enum_entry {
  41         unsigned long long start, end;  /* start and end are inclusive */
  42         const char *string;
  43 };
  44
  45 #define __type_integer(_type, _byte_order)                      \
  46         {                                                       \
  47             .atype = atype_integer,                             \
  48             .u.basic.integer =                                  \
  49                 {                                               \
  50                   .size = sizeof(_type),                        \
  51                   .alignment = ltt_alignof(_type) * CHAR_BIT,   \
  52                   .signedness = is_signed_type(_type),          \
  53                   .reverse_byte_order = _byte_order != __BYTE_ORDER,    \
  54                 },                                              \
  55         }                                                       \
  56
  57 struct lttng_integer_type {
  58         unsigned int size;              /* in bits */
  59         unsigned short alignment;       /* in bits */
  60         unsigned int signedness:1;
  61         unsigned int reverse_byte_order:1;
  62 };
  63
  64 union _lttng_basic_type {
  65         struct lttng_integer_type integer;
  66         struct {
  67                 const char *name;
  68         } enumeration;
  69         struct {
  70                 enum lttng_string_encodings encoding;
  71         } string;
  72 };
  73
  74 struct lttng_basic_type {
  75         enum abstract_types atype;
  76         union {
  77                 union _lttng_basic_type basic;
  78         } u;
  79 };
  80
  81 struct lttng_type {
  82         enum abstract_types atype;
  83         union {
  84                 union _lttng_basic_type basic;
  85                 struct {
  86                         struct lttng_basic_type elem_type;
  87                         unsigned int length;            /* num. elems. */
  88                 } array;
  89                 struct {
  90                         struct lttng_basic_type length_type;
  91                         struct lttng_basic_type elem_type;
  92                 } sequence;
  93         } u;
  94 };
  95
  96 struct lttng_enum {
  97         const char *name;
  98         struct lttng_type container_type;
  99         const struct lttng_enum_entry *entries;
 100         unsigned int len;
 101 };
 102
 103 /* Event field description */
 104
 105 struct lttng_event_field {
 106         const char *name;
 107         const struct lttng_type type;
 108 };
 109
 110 struct lttng_event_desc {
 111         const struct lttng_event_field *fields;
 112         const char *name;
 113         void *probe_callback;
 114         unsigned int nr_fields;
 115 };
 116
 117 struct lttng_probe_desc {
 118         const struct lttng_event_desc *event_desc;
 119         unsigned int nr_events;
 120         struct list_head head;                  /* chain registered probes */
 121 };
 122
 123 /*
 124  * ltt_event structure is referred to by the tracing fast path. It must be
 125  * kept small.
 126  */
 127 struct ltt_event {
 128         unsigned int id;
 129         struct ltt_channel *chan;
 130         const struct lttng_event_desc *desc;
 131         void *filter;
 132         enum lttng_kernel_instrumentation instrumentation;
 133         union {
 134                 struct {
 135                         struct kprobe kp;
 136                         char *symbol_name;
 137                 } kprobe;
 138         } u;
 139         struct list_head list;          /* Event list */
 140         int metadata_dumped:1;
 141 };
 142
 143 struct ltt_channel_ops {
 144         struct channel *(*channel_create)(const char *name,
 145                                 struct ltt_channel *ltt_chan,
 146                                 void *buf_addr,
 147                                 size_t subbuf_size, size_t num_subbuf,
 148                                 unsigned int switch_timer_interval,
 149                                 unsigned int read_timer_interval);
 150         void (*channel_destroy)(struct channel *chan);
 151         struct lib_ring_buffer *(*buffer_read_open)(struct channel *chan);
 152         void (*buffer_read_close)(struct lib_ring_buffer *buf);
 153         int (*event_reserve)(struct lib_ring_buffer_ctx *ctx);
 154         void (*event_commit)(struct lib_ring_buffer_ctx *ctx);
 155         void (*event_write)(struct lib_ring_buffer_ctx *ctx, const void *src,
 156                             size_t len);
 157         /*
 158          * packet_avail_size returns the available size in the current
 159          * packet. Note that the size returned is only a hint, since it
 160          * may change due to concurrent writes.
 161          */
 162         size_t (*packet_avail_size)(struct channel *chan);
 163         wait_queue_head_t *(*get_reader_wait_queue)(struct ltt_channel *chan);
 164 };
 165
 166 struct ltt_channel {
 167         unsigned int id;
 168         struct channel *chan;           /* Channel buffers */
 169         /* Event ID management */
 170         struct ltt_session *session;
 171         struct file *file;              /* File associated to channel */
 172         unsigned int free_event_id;     /* Next event ID to allocate */
 173         struct list_head list;          /* Channel list */
 174         wait_queue_head_t notify_wait;  /* Channel addition notif. waitqueue */
 175         struct ltt_channel_ops *ops;
 176         int header_type;                /* 0: unset, 1: compact, 2: large */
 177         int metadata_dumped:1;
 178 };
 179
 180 struct ltt_session {
 181         int active;                     /* Is trace session active ? */
 182         struct file *file;              /* File associated to session */
 183         struct ltt_channel *metadata;   /* Metadata channel */
 184         struct list_head chan;          /* Channel list head */
 185         struct list_head events;        /* Event list head */
 186         struct list_head list;          /* Session list */
 187         unsigned int free_chan_id;      /* Next chan ID to allocate */
 188         uuid_le uuid;                   /* Trace session unique ID */
 189         int metadata_dumped:1;
 190 };
 191
 192 struct ltt_transport {
 193         char *name;
 194         struct module *owner;
 195         struct list_head node;
 196         struct ltt_channel_ops ops;
 197 };
 198
 199 struct ltt_session *ltt_session_create(void);
 200 int ltt_session_start(struct ltt_session *session);
 201 int ltt_session_stop(struct ltt_session *session);
 202 void ltt_session_destroy(struct ltt_session *session);
 203
 204 struct ltt_channel *ltt_channel_create(struct ltt_session *session,
 205                                        const char *transport_name,
 206                                        void *buf_addr,
 207                                        size_t subbuf_size, size_t num_subbuf,
 208                                        unsigned int switch_timer_interval,
 209                                        unsigned int read_timer_interval);
 210 struct ltt_channel *ltt_global_channel_create(struct ltt_session *session,
 211                                        int overwrite, void *buf_addr,
 212                                        size_t subbuf_size, size_t num_subbuf,
 213                                        unsigned int switch_timer_interval,
 214                                        unsigned int read_timer_interval);
 215 void _ltt_channel_destroy(struct ltt_channel *chan);
 216
 217 struct ltt_event *ltt_event_create(struct ltt_channel *chan,
 218                                    char *name,
 219                                    struct lttng_kernel_event *event_param,
 220                                    const struct lttng_event_desc *event_desc,
 221                                    void *filter);
 222 int ltt_event_unregister(struct ltt_event *event);
 223
 224 void ltt_transport_register(struct ltt_transport *transport);
 225 void ltt_transport_unregister(struct ltt_transport *transport);
 226
 227 int ltt_debugfs_abi_init(void);
 228 void ltt_debugfs_abi_exit(void);
 229
 230 int ltt_probe_register(struct lttng_probe_desc *desc);
 231 void ltt_probe_unregister(struct lttng_probe_desc *desc);
 232 const struct lttng_event_desc *ltt_event_get(const char *name);
 233 void ltt_event_put(const struct lttng_event_desc *desc);
 234 int ltt_probes_init(void);
 235 void ltt_probes_exit(void);
 236
 237 void lttng_kprobes_handler_pre(struct kprobe *p, struct pt_regs *regs);
 238
 239 #endif /* _LTT_EVENTS_H */