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_none = 0,
  36         lttng_encode_UTF8 = 1,
  37         lttng_encode_ASCII = 2,
  38         NR_STRING_ENCODINGS,
  39 };
  40
  41 struct lttng_enum_entry {
  42         unsigned long long start, end;  /* start and end are inclusive */
  43         const char *string;
  44 };
  45
  46 #define __type_integer(_type, _byte_order, _base)               \
  47         {                                                       \
  48             .atype = atype_integer,                             \
  49             .u.basic.integer =                                  \
  50                 {                                               \
  51                   .size = sizeof(_type),                        \
  52                   .alignment = ltt_alignof(_type) * CHAR_BIT,   \
  53                   .signedness = is_signed_type(_type),          \
  54                   .reverse_byte_order = _byte_order != __BYTE_ORDER,    \
  55                   .base = _base,                                \
  56                   .encoding = lttng_encode_none,                \
  57                 },                                              \
  58         }                                                       \
  59
  60 struct lttng_integer_type {
  61         unsigned int size;              /* in bits */
  62         unsigned short alignment;       /* in bits */
  63         unsigned int signedness:1;
  64         unsigned int reverse_byte_order:1;
  65         unsigned int base;              /* 2, 8, 10, 16, for pretty print */
  66         enum lttng_string_encodings encoding;
  67 };
  68
  69 union _lttng_basic_type {
  70         struct lttng_integer_type integer;
  71         struct {
  72                 const char *name;
  73         } enumeration;
  74         struct {
  75                 enum lttng_string_encodings encoding;
  76         } string;
  77 };
  78
  79 struct lttng_basic_type {
  80         enum abstract_types atype;
  81         union {
  82                 union _lttng_basic_type basic;
  83         } u;
  84 };
  85
  86 struct lttng_type {
  87         enum abstract_types atype;
  88         union {
  89                 union _lttng_basic_type basic;
  90                 struct {
  91                         struct lttng_basic_type elem_type;
  92                         unsigned int length;            /* num. elems. */
  93                 } array;
  94                 struct {
  95                         struct lttng_basic_type length_type;
  96                         struct lttng_basic_type elem_type;
  97                 } sequence;
  98         } u;
  99 };
 100
 101 struct lttng_enum {
 102         const char *name;
 103         struct lttng_type container_type;
 104         const struct lttng_enum_entry *entries;
 105         unsigned int len;
 106 };
 107
 108 /* Event field description */
 109
 110 struct lttng_event_field {
 111         const char *name;
 112         struct lttng_type type;
 113 };
 114
 115 struct lttng_event_ctx {
 116         const struct lttng_event_field *fields;
 117         unsigned int nr_fields;
 118 };
 119
 120 struct lttng_event_desc {
 121         const char *name;
 122         void *probe_callback;
 123         const struct lttng_event_ctx *ctx;      /* context */
 124         const struct lttng_event_field *fields; /* event payload */
 125         unsigned int nr_fields;
 126 };
 127
 128 struct lttng_probe_desc {
 129         const struct lttng_event_desc *event_desc;
 130         unsigned int nr_events;
 131         struct list_head head;                  /* chain registered probes */
 132 };
 133
 134 /*
 135  * ltt_event structure is referred to by the tracing fast path. It must be
 136  * kept small.
 137  */
 138 struct ltt_event {
 139         unsigned int id;
 140         struct ltt_channel *chan;
 141         const struct lttng_event_desc *desc;
 142         void *filter;
 143         enum lttng_kernel_instrumentation instrumentation;
 144         union {
 145                 struct {
 146                         struct kprobe kp;
 147                         char *symbol_name;
 148                 } kprobe;
 149                 struct {
 150                         char *symbol_name;
 151                 } ftrace;
 152         } u;
 153         struct list_head list;          /* Event list */
 154         int metadata_dumped:1;
 155 };
 156
 157 struct ltt_channel_ops {
 158         struct channel *(*channel_create)(const char *name,
 159                                 struct ltt_channel *ltt_chan,
 160                                 void *buf_addr,
 161                                 size_t subbuf_size, size_t num_subbuf,
 162                                 unsigned int switch_timer_interval,
 163                                 unsigned int read_timer_interval);
 164         void (*channel_destroy)(struct channel *chan);
 165         struct lib_ring_buffer *(*buffer_read_open)(struct channel *chan);
 166         void (*buffer_read_close)(struct lib_ring_buffer *buf);
 167         int (*event_reserve)(struct lib_ring_buffer_ctx *ctx);
 168         void (*event_commit)(struct lib_ring_buffer_ctx *ctx);
 169         void (*event_write)(struct lib_ring_buffer_ctx *ctx, const void *src,
 170                             size_t len);
 171         /*
 172          * packet_avail_size returns the available size in the current
 173          * packet. Note that the size returned is only a hint, since it
 174          * may change due to concurrent writes.
 175          */
 176         size_t (*packet_avail_size)(struct channel *chan);
 177         wait_queue_head_t *(*get_reader_wait_queue)(struct ltt_channel *chan);
 178 };
 179
 180 struct ltt_channel {
 181         unsigned int id;
 182         struct channel *chan;           /* Channel buffers */
 183         /* Event ID management */
 184         struct ltt_session *session;
 185         struct file *file;              /* File associated to channel */
 186         unsigned int free_event_id;     /* Next event ID to allocate */
 187         struct list_head list;          /* Channel list */
 188         wait_queue_head_t notify_wait;  /* Channel addition notif. waitqueue */
 189         struct ltt_channel_ops *ops;
 190         int header_type;                /* 0: unset, 1: compact, 2: large */
 191         int metadata_dumped:1;
 192 };
 193
 194 struct ltt_session {
 195         int active;                     /* Is trace session active ? */
 196         struct file *file;              /* File associated to session */
 197         struct ltt_channel *metadata;   /* Metadata channel */
 198         struct list_head chan;          /* Channel list head */
 199         struct list_head events;        /* Event list head */
 200         struct list_head list;          /* Session list */
 201         unsigned int free_chan_id;      /* Next chan ID to allocate */
 202         uuid_le uuid;                   /* Trace session unique ID */
 203         int metadata_dumped:1;
 204 };
 205
 206 struct ltt_transport {
 207         char *name;
 208         struct module *owner;
 209         struct list_head node;
 210         struct ltt_channel_ops ops;
 211 };
 212
 213 struct ltt_session *ltt_session_create(void);
 214 int ltt_session_start(struct ltt_session *session);
 215 int ltt_session_stop(struct ltt_session *session);
 216 void ltt_session_destroy(struct ltt_session *session);
 217
 218 struct ltt_channel *ltt_channel_create(struct ltt_session *session,
 219                                        const char *transport_name,
 220                                        void *buf_addr,
 221                                        size_t subbuf_size, size_t num_subbuf,
 222                                        unsigned int switch_timer_interval,
 223                                        unsigned int read_timer_interval);
 224 struct ltt_channel *ltt_global_channel_create(struct ltt_session *session,
 225                                        int overwrite, void *buf_addr,
 226                                        size_t subbuf_size, size_t num_subbuf,
 227                                        unsigned int switch_timer_interval,
 228                                        unsigned int read_timer_interval);
 229 void _ltt_channel_destroy(struct ltt_channel *chan);
 230
 231 struct ltt_event *ltt_event_create(struct ltt_channel *chan,
 232                                    char *name,
 233                                    struct lttng_kernel_event *event_param,
 234                                    void *filter);
 235 int ltt_event_unregister(struct ltt_event *event);
 236
 237 void ltt_transport_register(struct ltt_transport *transport);
 238 void ltt_transport_unregister(struct ltt_transport *transport);
 239
 240 int ltt_debugfs_abi_init(void);
 241 void ltt_debugfs_abi_exit(void);
 242
 243 int ltt_probe_register(struct lttng_probe_desc *desc);
 244 void ltt_probe_unregister(struct lttng_probe_desc *desc);
 245 const struct lttng_event_desc *ltt_event_get(const char *name);
 246 void ltt_event_put(const struct lttng_event_desc *desc);
 247 int ltt_probes_init(void);
 248 void ltt_probes_exit(void);
 249
 250 #ifdef CONFIG_KPROBES
 251 int lttng_kprobes_register(const char *name,
 252                 const char *symbol_name,
 253                 uint64_t offset,
 254                 uint64_t addr,
 255                 struct ltt_event *event);
 256 void lttng_kprobes_unregister(struct ltt_event *event);
 257 #else
 258 static inline
 259 int lttng_kprobes_register(const char *name,
 260                 const char *symbol_name,
 261                 uint64_t offset,
 262                 uint64_t addr,
 263                 struct ltt_event *event)
 264 {
 265         return -ENOSYS;
 266 }
 267
 268 void lttng_kprobes_unregister(struct ltt_event *event)
 269 {
 270 }
 271 #endif
 272
 273 #ifdef CONFIG_DYNAMIC_FTRACE
 274 int lttng_ftrace_register(const char *name,
 275                           const char *symbol_name,
 276                           struct ltt_event *event);
 277 void lttng_ftrace_unregister(struct ltt_event *event);
 278 #else
 279 static inline
 280 int lttng_ftrace_register(const char *name,
 281                           const char *symbol_name,
 282                           struct ltt_event *event)
 283 {
 284         return -ENOSYS;
 285 }
 286
 287 static inline
 288 void lttng_ftrace_unregister(struct ltt_event *event)
 289 {
 290 }
 291 #endif
 292 #endif /* _LTT_EVENTS_H */