1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
|
/******************************************************
Sessions
(c) 1996 Innobase Oy
Created 6/25/1996 Heikki Tuuri
*******************************************************/
#ifndef usr0sess_h
#define usr0sess_h
#include "univ.i"
#include "ut0byte.h"
#include "hash0hash.h"
#include "trx0types.h"
#include "srv0srv.h"
#include "trx0types.h"
#include "usr0types.h"
#include "que0types.h"
#include "data0data.h"
#include "rem0rec.h"
#include "com0com.h"
/* The session system global data structure */
extern sess_sys_t* sess_sys;
/*************************************************************************
Sets the session id in a client message. */
void
sess_cli_msg_set_sess(
/*==================*/
byte* str, /* in/out: message string */
dulint sess_id);/* in: session id */
/***************************************************************************
Sets the message type of a message from the client. */
UNIV_INLINE
void
sess_cli_msg_set_type(
/*==================*/
byte* str, /* in: message string */
ulint type); /* in: message type */
/***************************************************************************
Gets the message type of a message from the server. */
UNIV_INLINE
ulint
sess_srv_msg_get_type(
/*==================*/
/* out: message type */
byte* str); /* in: message string */
/***************************************************************************
Creates a session sytem at database start. */
void
sess_sys_init_at_db_start(void);
/*===========================*/
/*************************************************************************
Opens a session. */
sess_t*
sess_open(
/*======*/
/* out, own: session object */
com_endpoint_t* endpoint, /* in: communication endpoint used
for communicating with the client */
byte* addr_buf, /* in: client address */
ulint addr_len); /* in: client address length */
/*************************************************************************
Closes a session, freeing the memory occupied by it. */
void
sess_close(
/*=======*/
sess_t* sess); /* in, own: session object */
/*************************************************************************
Raises an SQL error. */
void
sess_raise_error_low(
/*=================*/
trx_t* trx, /* in: transaction */
ulint err_no, /* in: error number */
ulint type, /* in: more info of the error, or 0 */
dict_table_t* table, /* in: dictionary table or NULL */
dict_index_t* index, /* in: table index or NULL */
dtuple_t* tuple, /* in: tuple to insert or NULL */
rec_t* rec, /* in: record or NULL */
char* err_str);/* in: arbitrary null-terminated error string,
or NULL */
/*************************************************************************
Closes a session, freeing the memory occupied by it, if it is in a state
where it should be closed. */
ibool
sess_try_close(
/*===========*/
/* out: TRUE if closed */
sess_t* sess); /* in, own: session object */
/*************************************************************************
Initializes the first fields of a message to client. */
void
sess_srv_msg_init(
/*==============*/
sess_t* sess, /* in: session object */
byte* buf, /* in: message buffer, must be at least of size
SESS_SRV_MSG_DATA */
ulint type); /* in: message type */
/*************************************************************************
Sends a simple message to client. */
void
sess_srv_msg_send_simple(
/*=====================*/
sess_t* sess, /* in: session object */
ulint type, /* in: message type */
ulint rel_kernel); /* in: SESS_RELEASE_KERNEL or
SESS_NOT_RELEASE_KERNEL */
/***************************************************************************
Processes a message from a client. NOTE: May release the kernel mutex
temporarily. */
void
sess_receive_msg_rel_kernel(
/*========================*/
sess_t* sess, /* in: session */
byte* str, /* in: message string */
ulint len); /* in: message length */
/***************************************************************************
When a command has been completed, this function sends the message about it
to the client. */
void
sess_command_completed_message(
/*===========================*/
sess_t* sess, /* in: session */
byte* msg, /* in: message buffer */
ulint len); /* in: message data length */
/***********************************************************************
Starts a new connection and a session, or starts a query based on a client
message. This is called by a SRV_COM thread. */
void
sess_process_cli_msg(
/*=================*/
byte* str, /* in: message string */
ulint len, /* in: string length */
byte* addr, /* in: address string */
ulint alen); /* in: address length */
/* The session handle. All fields are protected by the kernel mutex */
struct sess_struct{
dulint id; /* session id */
dulint usr_id; /* user id */
hash_node_t hash; /* hash chain node */
ulint refer_count; /* reference count to the session
object: when this drops to zero
and the session has no query graphs
left, discarding the session object
is allowed */
dulint error_count; /* if this counter has increased while
a thread is parsing an SQL command,
its graph should be discarded */
ibool disconnecting; /* TRUE if the session is to be
disconnected when its reference
count drops to 0 */
ulint state; /* state of the session */
dulint msgs_sent; /* count of messages sent to the
client */
dulint msgs_recv; /* count of messages received from the
client */
ibool client_waits; /* when the session receives a message
from the client, this set to TRUE, and
when the session sends a message to
the client this is set to FALSE */
trx_t* trx; /* transaction object permanently
assigned for the session: the
transaction instance designated by the
trx id changes, but the memory
structure is preserved */
ulint next_graph_id; /* next query graph id to assign */
UT_LIST_BASE_NODE_T(que_t)
graphs; /* query graphs belonging to this
session */
/*------------------------------*/
ulint err_no; /* latest error number, 0 if none */
char* err_str; /* latest error string */
ulint err_len; /* error string length */
/*------------------------------*/
com_endpoint_t* endpoint; /* server communications endpoint used
to communicate with the client */
char* addr_buf; /* client address string */
ulint addr_len; /* client address string length */
/*------------------------------*/
byte* big_msg; /* if the client sends a message which
does not fit in a single packet,
it is assembled in this buffer; if
this field is not NULL, it is assumed
that the message should be catenated
here */
ulint big_msg_size; /* size of the big message buffer */
ulint big_msg_len; /* length of data in the big message
buffer */
};
/* The session system; this is protected by the kernel mutex */
struct sess_sys_struct{
ulint state; /* state of the system:
SESS_SYS_RUNNING or
SESS_SYS_SHUTTING_DOWN */
sess_t* shutdown_req; /* if shutdown was requested by some
session, confirmation of shutdown
completion should be sent to this
session */
dulint free_sess_id; /* first unused session id */
hash_table_t* hash; /* hash table of the sessions */
};
/*---------------------------------------------------*/
/* The format of an incoming message from a client */
#define SESS_CLI_MSG_CHECKSUM 0 /* the checksum should be the first
field in the message */
#define SESS_CLI_MSG_SESS_ID 4 /* this is set to 0 if the client
wants to connect and establish
a new session */
#define SESS_CLI_MSG_SESS_ID_CHECK 12 /* checksum of the sess id field */
#define SESS_CLI_MSG_TYPE 16
#define SESS_CLI_MSG_NO 20
#define SESS_CLI_MSG_CONTINUE 28 /* 0, or SESS_MSG_FIRST_PART
SESS_MSG_MIDDLE_PART, or
SESS_MSG_LAST_PART */
#define SESS_CLI_MSG_CONT_SIZE 32 /* size of a multipart message in
kilobytes (rounded upwards) */
#define SESS_CLI_MSG_DATA 36
/*---------------------------------------------------*/
/* Client-to-session message types */
#define SESS_CLI_CONNECT 1
#define SESS_CLI_PREPARE 2
#define SESS_CLI_EXECUTE 3
#define SESS_CLI_BREAK_EXECUTION 4
/* Client-to-session statement command types */
#define SESS_COMM_FETCH_NEXT 1
#define SESS_COMM_FETCH_PREV 2
#define SESS_COMM_FETCH_FIRST 3
#define SESS_COMM_FETCH_LAST 4
#define SESS_COMM_FETCH_NTH 5
#define SESS_COMM_FETCH_NTH_LAST 6
#define SESS_COMM_EXECUTE 7
#define SESS_COMM_NO_COMMAND 8
/*---------------------------------------------------*/
/* The format of an outgoing message from a session to the client */
#define SESS_SRV_MSG_CHECKSUM 0 /* the checksum should be the first
field in the message */
#define SESS_SRV_MSG_SESS_ID 4
#define SESS_SRV_MSG_TYPE 12
#define SESS_SRV_MSG_NO 16
#define SESS_SRV_MSG_CONTINUE 24 /* 0, or SESS_MSG_FIRST_PART
SESS_MSG_MIDDLE_PART, or
SESS_MSG_LAST_PART */
#define SESS_SRV_MSG_CONT_SIZE 28 /* size of a multipart message
in kilobytes (rounded upward) */
#define SESS_SRV_MSG_DATA 32
/*---------------------------------------------------*/
/* Session-to-client message types */
#define SESS_SRV_ACCEPT_CONNECT 1
#define SESS_SRV_SUCCESS 2
#define SESS_SRV_ERROR 3
/* Multipart messages */
#define SESS_MSG_SINGLE_PART 0
#define SESS_MSG_FIRST_PART 1
#define SESS_MSG_MIDDLE_PART 2
#define SESS_MSG_LAST_PART 3
/* Error numbers */
#define SESS_ERR_NONE 0
#define SESS_ERR_TRX_COMMITTED 1
#define SESS_ERR_TRX_ROLLED_BACK 2
#define SESS_ERR_SESSION_DISCONNECTED 3
#define SESS_ERR_REPLY_FAILED 4
#define SESS_ERR_CANNOT_BREAK_OP 5
#define SESS_ERR_MSG_LOST 6
#define SESS_ERR_MSG_CORRUPTED 7
#define SESS_ERR_EXTRANEOUS_MSG 8
#define SESS_ERR_OUT_OF_MEMORY 9
#define SESS_ERR_SQL_ERROR 10
#define SESS_ERR_STMT_NOT_FOUND 11
#define SESS_ERR_STMT_NOT_READY 12
#define SESS_ERR_EXTRANEOUS_SRV_MSG 13
#define SESS_ERR_BREAK_BY_CLIENT 14
/* Session states */
#define SESS_ACTIVE 1
#define SESS_ERROR 2 /* session contains an error message
which has not yet been communicated
to the client */
/* Session system states */
#define SESS_SYS_RUNNING 1
#define SESS_SYS_SHUTTING_DOWN 2
/* Session hash table size */
#define SESS_HASH_SIZE 1024
/* Flags used in sess_srv_msg_send */
#define SESS_RELEASE_KERNEL 1
#define SESS_NOT_RELEASE_KERNEL 2
#ifndef UNIV_NONINL
#include "usr0sess.ic"
#endif
#endif
|
