slave IO流程之一：mysql登陆过程（mysql_real_connect）

 1   if (!net->vio &&
 2       (!mysql->options.protocol ||
 3        mysql->options.protocol == MYSQL_PROTOCOL_SOCKET) &&
 4       (unix_socket || mysql_unix_port) &&
 5       (!host || !strcmp(host,LOCAL_HOST)))
 6   {
 7     my_socket sock= socket(AF_UNIX, SOCK_STREAM, 0);
 8     DBUG_PRINT("info", ("Using socket"));
 9     if (sock == SOCKET_ERROR)
10     {
11       set_mysql_extended_error(mysql, CR_SOCKET_CREATE_ERROR,
12                                unknown_sqlstate,
13                                ER(CR_SOCKET_CREATE_ERROR),
14                                socket_errno);
15       goto error;
16     }
17 
18     net->vio= vio_new(sock, VIO_TYPE_SOCKET,
19                       VIO_LOCALHOST | VIO_BUFFERED_READ);
20     if (!net->vio)
21     {
22       DBUG_PRINT("error",("Unknow protocol %d ", mysql->options.protocol));
23       set_mysql_error(mysql, CR_CONN_UNKNOW_PROTOCOL, unknown_sqlstate);
24       closesocket(sock);
25       goto error;
26     }
27 
28     host= LOCAL_HOST;
29     if (!unix_socket)
30       unix_socket= mysql_unix_port;
31     host_info= (char*) ER(CR_LOCALHOST_CONNECTION);
32     DBUG_PRINT("info", ("Using UNIX sock ‘%s‘", unix_socket));
33 
34     memset(&UNIXaddr, 0, sizeof(UNIXaddr));
35     UNIXaddr.sun_family= AF_UNIX;
36     strmake(UNIXaddr.sun_path, unix_socket, sizeof(UNIXaddr.sun_path)-1);
37 
38     if (vio_socket_connect(net->vio, (struct sockaddr *) &UNIXaddr,
39                            sizeof(UNIXaddr), get_vio_connect_timeout(mysql)))
40     {
41       DBUG_PRINT("error",("Got error %d on connect to local server",
42               socket_errno));
43       set_mysql_extended_error(mysql, CR_CONNECTION_ERROR,
44                                unknown_sqlstate,
45                                ER(CR_CONNECTION_ERROR),
46                                unix_socket, socket_errno);
47       vio_delete(net->vio);
48       net->vio= 0;
49       goto error;
50     }
51     mysql->options.protocol=MYSQL_PROTOCOL_SOCKET;
52   }

  1 for (t_res= res_lst; t_res; t_res= t_res->ai_next)
  2     {
  3       DBUG_PRINT("info", ("Create socket, family: %d  type: %d  proto: %d",
  4                           t_res->ai_family, t_res->ai_socktype,
  5                           t_res->ai_protocol));
  6 
  7       sock= socket(t_res->ai_family, t_res->ai_socktype, t_res->ai_protocol);
  8       if (sock == SOCKET_ERROR)
  9       {
 10         DBUG_PRINT("info", ("Socket created was invalid"));
 11         /* Try next address if there is one */
 12         saved_error= socket_errno;
 13         continue;
 14       }
 15 
 16       if (client_bind_ai_lst)
 17       {
 18         struct addrinfo* curr_bind_ai= NULL;
 19         DBUG_PRINT("info", ("Attempting to bind socket to bind address(es)"));
 20 
 21         /*
 22            We‘ll attempt to bind to each of the addresses returned, until
 23            we find one that works.
 24            If none works, we‘ll try the next destination host address
 25            (if any)
 26         */
 27         curr_bind_ai= client_bind_ai_lst;
 28 
 29         while (curr_bind_ai != NULL)
 30         {
 31           /* Attempt to bind the socket to the given address */
 32           bind_result= bind(sock,
 33                             curr_bind_ai->ai_addr,
 34                             curr_bind_ai->ai_addrlen);
 35           if (!bind_result)
 36             break;   /* Success */
 37 
 38           DBUG_PRINT("info", ("bind failed, attempting another bind address"));
 39           /* Problem with the bind, move to next address if present */
 40           curr_bind_ai= curr_bind_ai->ai_next;
 41         }
 42 
 43         if (bind_result)
 44         {
 45           /*
 46             Could not bind to any client-side address with this destination
 47              Try the next destination address (if any)
 48           */
 49           DBUG_PRINT("info", ("All bind attempts with this address failed"));
 50           saved_error= socket_errno;
 51           closesocket(sock);
 52           continue;
 53         }
 54         DBUG_PRINT("info", ("Successfully bound client side of socket"));
 55       }
 56 
 57       /* Create a new Vio object to abstract the socket. */
 58       if (!net->vio)
 59       {
 60         if (!(net->vio= vio_new(sock, VIO_TYPE_TCPIP, flags)))
 61         {
 62           set_mysql_error(mysql, CR_OUT_OF_MEMORY, unknown_sqlstate);
 63           closesocket(sock);
 64           freeaddrinfo(res_lst);
 65           if (client_bind_ai_lst)
 66             freeaddrinfo(client_bind_ai_lst);
 67           goto error;
 68         }
 69       }
 70       /* Just reinitialize if one is already allocated. */
 71       else if (vio_reset(net->vio, VIO_TYPE_TCPIP, sock, NULL, flags))
 72       {
 73         set_mysql_error(mysql, CR_UNKNOWN_ERROR, unknown_sqlstate);
 74         closesocket(sock);
 75         freeaddrinfo(res_lst);
 76         if (client_bind_ai_lst)
 77           freeaddrinfo(client_bind_ai_lst);
 78         goto error;
 79       }
 80 
 81       DBUG_PRINT("info", ("Connect socket"));
 82       status= vio_socket_connect(net->vio, t_res->ai_addr,
 83                                  (socklen_t)t_res->ai_addrlen,
 84                                  get_vio_connect_timeout(mysql));
 85       /*
 86         Here we rely on vio_socket_connect() to return success only if
 87         the connect attempt was really successful. Otherwise we would
 88         stop trying another address, believing we were successful.
 89       */
 90       if (!status)
 91         break;
 92 
 93       /*
 94         Save either the socket error status or the error code of
 95         the failed vio_connection operation. It is necessary to
 96         avoid having it overwritten by later operations.
 97       */
 98       saved_error= socket_errno;
 99 
100       DBUG_PRINT("info", ("No success, try next address."));
101     }

 1  if ((pkt_length=cli_safe_read(mysql, NULL)) == packet_error)
 2   {
 3     if (mysql->net.last_errno == CR_SERVER_LOST)
 4       set_mysql_extended_error(mysql, CR_SERVER_LOST, unknown_sqlstate,
 5                                ER(CR_SERVER_LOST_EXTENDED),
 6                                "reading initial communication packet",
 7                                socket_errno);
 8     goto error;
 9   }
10   pkt_end= (char*)net->read_pos + pkt_length;
11   /* Check if version of protocol matches current one */
12   mysql->protocol_version= net->read_pos[0];
13   DBUG_DUMP("packet",(uchar*) net->read_pos,10);
14   DBUG_PRINT("info",("mysql protocol version %d, server=%d",
15              PROTOCOL_VERSION, mysql->protocol_version));
16   if (mysql->protocol_version != PROTOCOL_VERSION)
17   {
18     set_mysql_extended_error(mysql, CR_VERSION_ERROR, unknown_sqlstate,
19                              ER(CR_VERSION_ERROR), mysql->protocol_version,
20                              PROTOCOL_VERSION);
21     goto error;
22   }
23   server_version_end= end= strend((char*) net->read_pos+1);
24   mysql->thread_id=uint4korr((uchar*) end + 1);
25   end+=5;
26   /* 
27     Scramble is split into two parts because old clients do not understand
28     long scrambles; here goes the first part.
29   */
30   scramble_data= end;
31   scramble_data_len= AUTH_PLUGIN_DATA_PART_1_LENGTH + 1;
32   scramble_plugin= NULL;
33   end+= scramble_data_len;
34 
35   if (pkt_end >= end + 1)
36     mysql->server_capabilities=uint2korr((uchar*) end);
37   if (pkt_end >= end + 18)
38   {
39     /* New protocol with 16 bytes to describe server characteristics */
40     mysql->server_language=end[2];
41     mysql->server_status=uint2korr((uchar*) end + 3);
42     mysql->server_capabilities|= uint2korr((uchar*) end + 5) << 16;
43     pkt_scramble_len= end[7];
44     if (pkt_scramble_len < 0)
45     {
46       set_mysql_error(mysql, CR_MALFORMED_PACKET,
47                       unknown_sqlstate);        /* purecov: inspected */
48       goto error;
49     }
50   }
51   end+= 18;
52 
53   if (mysql_init_character_set(mysql))
54     goto error;

 1   mpvio.mysql_change_user= data_plugin == 0;
 2   mpvio.cached_server_reply.pkt= (uchar*)data;
 3   mpvio.cached_server_reply.pkt_len= data_len;
 4   mpvio.read_packet= client_mpvio_read_packet;
 5   mpvio.write_packet= client_mpvio_write_packet;
 6   mpvio.info= client_mpvio_info;
 7   mpvio.mysql= mysql;
 8   mpvio.packets_read= mpvio.packets_written= 0;
 9   mpvio.db= db;
10   mpvio.plugin= auth_plugin;
11 
12   MYSQL_TRACE(AUTH_PLUGIN, mysql, (auth_plugin->name));
13 
14   res= auth_plugin->authenticate_user((struct st_plugin_vio *)&mpvio, mysql);

 1 static int native_password_auth_client(MYSQL_PLUGIN_VIO *vio, MYSQL *mysql)
 2 {
 3   int pkt_len;
 4   uchar *pkt;
 5 
 6   DBUG_ENTER("native_password_auth_client");
 7 
 8 
 9   if (((MCPVIO_EXT *)vio)->mysql_change_user)
10   {
11     /*
12       in mysql_change_user() the client sends the first packet.
13       we use the old scramble.
14     */
15     pkt= (uchar*)mysql->scramble;
16     pkt_len= SCRAMBLE_LENGTH + 1;
17   }
18   else
19   {
20     /* read the scramble */
21     if ((pkt_len= vio->read_packet(vio, &pkt)) < 0)
22       DBUG_RETURN(CR_ERROR);
23 
24     if (pkt_len != SCRAMBLE_LENGTH + 1)
25       DBUG_RETURN(CR_SERVER_HANDSHAKE_ERR);
26 
27     /* save it in MYSQL */
28     memcpy(mysql->scramble, pkt, SCRAMBLE_LENGTH);
29     mysql->scramble[SCRAMBLE_LENGTH] = 0;
30   }
31 
32   if (mysql->passwd[0])
33   {
34     char scrambled[SCRAMBLE_LENGTH + 1];
35     DBUG_PRINT("info", ("sending scramble"));
36     scramble(scrambled, (char*)pkt, mysql->passwd);
37     if (vio->write_packet(vio, (uchar*)scrambled, SCRAMBLE_LENGTH))
38       DBUG_RETURN(CR_ERROR);
39   }
40   else
41   {
42     DBUG_PRINT("info", ("no password"));
43     if (vio->write_packet(vio, 0, 0)) /* no password */
44       DBUG_RETURN(CR_ERROR);
45   }
46 
47   DBUG_RETURN(CR_OK);
48 }

1  /* read the OK packet (or use the cached value in mysql->net.read_pos */
2   if (res == CR_OK)
3     pkt_length= (*mysql->methods->read_change_user_result)(mysql);
4   else /* res == CR_OK_HANDSHAKE_COMPLETE */
5     pkt_length= mpvio.last_read_packet_len;

 1 int STDCALL
 2 mysql_select_db(MYSQL *mysql, const char *db)
 3 {
 4   int error;
 5   DBUG_ENTER("mysql_select_db");
 6   DBUG_PRINT("enter",("db: ‘%s‘",db));
 7 
 8   if ((error=simple_command(mysql,COM_INIT_DB, (const uchar*) db,
 9                             (ulong) strlen(db),0)))
10     DBUG_RETURN(error);
11   my_free(mysql->db);
12   mysql->db=my_strdup(key_memory_MYSQL,
13                       db,MYF(MY_WME));
14   DBUG_RETURN(0);
15 }

 1 1              [0a] protocol version
 2 string[NUL]    server version
 3 4              connection id
 4 string[8]      auth-plugin-data-part-1
 5 1              [00] filler
 6 2              capability flags (lower 2 bytes)
 7   if more data in the packet:
 8 1              character set
 9 2              status flags
10 2              capability flags (upper 2 bytes)
11   if capabilities & CLIENT_PLUGIN_AUTH {
12 1              length of auth-plugin-data
13   } else {
14 1              [00]
15   }
16 string[10]     reserved (all [00])
17   if capabilities & CLIENT_SECURE_CONNECTION {
18 string[$len]   auth-plugin-data-part-2 ($len=MAX(13, length of auth-plugin-data - 8))
19   if capabilities & CLIENT_PLUGIN_AUTH {
20 string[NUL]    auth-plugin name
21   }

 1 4              capability flags, CLIENT_PROTOCOL_41 always set
 2 4              max-packet size
 3 1              character set
 4 string[23]     reserved (all [0])
 5 string[NUL]    username
 6   if capabilities & CLIENT_PLUGIN_AUTH_LENENC_CLIENT_DATA {
 7 lenenc-int     length of auth-response
 8 string[n]      auth-response
 9   } else if capabilities & CLIENT_SECURE_CONNECTION {
10 1              length of auth-response
11 string[n]      auth-response
12   } else {
13 string[NUL]    auth-response
14   }
15   if capabilities & CLIENT_CONNECT_WITH_DB {
16 string[NUL]    database
17   }
18   if capabilities & CLIENT_PLUGIN_AUTH {
19 string[NUL]    auth plugin name
20   }
21   if capabilities & CLIENT_CONNECT_ATTRS {
22 lenenc-int     length of all key-values
23 lenenc-str     key
24 lenenc-str     value
25    if-more data in ‘length of all key-values‘, more keys and value pairs
26   }

 1 Type    Name    Description
 2 int<1>    header    [00] or [fe] the OK packet header
 3 int<lenenc>    affected_rows    affected rows
 4 int<lenenc>    last_insert_id    last insert-id
 5 if capabilities & CLIENT_PROTOCOL_41 {
 6   int<2>    status_flags    Status Flags
 7   int<2>    warnings    number of warnings
 8 } elseif capabilities & CLIENT_TRANSACTIONS {
 9   int<2>    status_flags    Status Flags
10 }
11 if capabilities & CLIENT_SESSION_TRACK {
12   string<lenenc>    info    human readable status information
13   if status_flags & SERVER_SESSION_STATE_CHANGED {
14     string<lenenc>    session_state_changes    session state info
15   }
16 } else {
17   string<EOF>    info    human readable status information
18 }