FreeTDS API

Functions
Network functions
LibTDS API

Functions for reading or writing from network. More...

Collaboration diagram for Network functions:

## Functions

static size_t | read_and_convert (TDSSOCKET *tds, TDSICONV *char_conv, size_t *wire_size, char *outbuf, size_t outbytesleft)
| For UTF-8 and similar, tds_iconv() may encounter a partial sequence when the chunk boundary is not aligned with the character boundary. More...
int | tds7_get_instance_port (struct addrinfo *addr, const char *instance)
| Get port of given instance. More...
int | tds7_get_instance_ports (FILE *output, struct addrinfo *addr)
| Get port of all instances. More...
const char * | tds_addrinfo2str (struct addrinfo *addr, char *name, int namemax)
static void | tds_addrinfo_set_port (struct addrinfo *addr, unsigned int port)
void | tds_close_socket (TDSSOCKET *tds)
| Close current socket. More...
static TDSERRNO | tds_connect_socket (TDSSOCKET *tds, struct addrinfo *addr, unsigned int port, int timeout, int *p_oserr)
void | tds_connection_close (TDSCONNECTION *conn)
int | tds_connection_read (TDSSOCKET *tds, unsigned char *buf, int buflen)
static int | tds_connection_signaled (TDSCONNECTION *conn)
int | tds_connection_write (TDSSOCKET *tds, const unsigned char *buf, int buflen, int final)
DSTR * | tds_dstr_get (TDSSOCKET *tds, DSTR *s, size_t len)
| Reads a string from wire and put in a DSTR. More...
TDSRET | tds_flush_packet (TDSSOCKET *tds)
| Flush packet to server. More...
unsigned char | tds_get_byte (TDSSOCKET *tds)
| Return a single byte from the input buffer. More...
TDSRET | tds_get_char_data (TDSSOCKET *tds, char *row_buffer, size_t wire_size, TDSCOLUMN *curcol)
| Fetch character data the wire. More...
void * | tds_get_n (TDSSOCKET *tds, void *dest, size_t need)
| Get N bytes from the buffer and return them in the already allocated space given to us. More...
size_t | tds_get_string (TDSSOCKET *tds, size_t string_len, char *dest, size_t dest_size)
| Fetch a string from the wire. More...
TDS_UINT | tds_get_uint (TDSSOCKET *tds)
| Get an int32 from the server. More...
TDS_UINT8 | tds_get_uint8 (TDSSOCKET *tds)
| Get an uint64 from the server. More...
TDS_USMALLINT | tds_get_usmallint (TDSSOCKET *tds)
| Get an int16 from the server.
int | tds_goodread (TDSSOCKET *tds, unsigned char *buf, int buflen)
| Loops until we have received some characters return -1 on failure.
int | tds_goodwrite (TDSSOCKET *tds, const unsigned char *buffer, size_t buflen)
int | tds_init_write_buf (TDSSOCKET *tds)
TDSERRNO | tds_open_socket (TDSSOCKET *tds, struct addrinfo *addr, unsigned int port, int timeout, int *p_oserr)
unsigned char | tds_peek (TDSSOCKET *tds)
| Reads a byte from the TDS stream without removing it. More...
int | tds_put_buf (TDSSOCKET *tds, const unsigned char *buf, int dsize, int ssize)
int | tds_put_byte (TDSSOCKET *tds, unsigned char c)
int | tds_put_cancel (TDSSOCKET *tds)
int | tds_put_int (TDSSOCKET *tds, TDS_INT i)
int | tds_put_int8 (TDSSOCKET *tds, TDS_INT8 i)
int | tds_put_n (TDSSOCKET *tds, const void *buf, size_t n)
int | tds_put_smallint (TDSSOCKET *tds, TDS_SMALLINT si)
int | tds_put_string (TDSSOCKET *tds, const char *s, int len)
| Output a string to wire automatic translate string to unicode if needed. More...
int | tds_read_packet (TDSSOCKET *tds)
| Read in one 'packet' from the server. More...
int | tds_select (TDSSOCKET *tds, unsigned tds_sel, int timeout_seconds)
| Select on a socket until it's available or the timeout expires. More...
void | tds_socket_flush (TDS_SYS_SOCKET sock)
static int | tds_socket_read (TDSCONNECTION *conn, TDSSOCKET *tds, unsigned char *buf, int buflen)
| Read from an OS socket remove tds, save error somewhere, report error in another way. More...
int | tds_socket_set_nonblocking (TDS_SYS_SOCKET sock)
| Set socket to non-blocking. More...
static int | tds_socket_write (TDSCONNECTION *conn, TDSSOCKET *tds, const unsigned char *buf, int buflen)
| Write to an OS socket. More...
void | tds_unget_byte (TDSSOCKET *tds)
| Unget will always work as long as you don't call it twice in a row. More...
void | tds_wakeup_close (TDSPOLLWAKEUP *wakeup)
int | tds_wakeup_init (TDSPOLLWAKEUP *wakeup)
void | tds_wakeup_send (TDSPOLLWAKEUP *wakeup, char cancel)
TDSRET | tds_write_packet (TDSSOCKET *tds, unsigned char final)

## Detailed Description

Functions for reading or writing from network.

## Function Documentation

## § read_and_convert()

static size_t read_and_convert | ( | TDSSOCKET * | tds,
|  | TDSICONV * | char_conv,
|  | size_t * | wire_size,
|  | char * | outbuf,
|  | size_t | outbytesleft
| ) |  |

static

For UTF-8 and similar, tds_iconv() may encounter a partial sequence when the chunk boundary is not aligned with the character boundary.

In that event, it will return an error, and some number of bytes (less than a character) will remain in the tail end of temp[]. They are moved to the beginning, ptemp is adjusted to point just behind them, and the next chunk is read.

Parameters

  | tds | A pointer to the TDSSOCKET structure managing a client/server operation.
  | char_conv | conversion structure
  [out] | wire_size | size readed from wire
  | outbuf | buffer to write to
  | outbytesleft | buffer length

Returns
  bytes readed

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## § tds7_get_instance_port()

int tds7_get_instance_port | ( | struct addrinfo * | addr,
|  | const char * | instance
| ) |  |

Get port of given instance.

Returns
  port number or 0 if error

## § tds7_get_instance_ports()

int tds7_get_instance_ports | ( | FILE * | output,
|  | struct addrinfo * | addr
| ) |  |

Get port of all instances.

Returns
  default port number or 0 if error

Remarks
  experimental, cf. MC-SQLR.pdf.

## § tds_close_socket()

void tds_close_socket | ( | TDSSOCKET * | tds | ) |

Close current socket.

For last socket close entire connection. For MARS send FIN request. This attempts a graceful disconnection, for ungraceful call tds_connection_close.

## § tds_dstr_get()

DSTR* tds_dstr_get | ( | TDSSOCKET * | tds,
|  | DSTR * | s,
|  | size_t | len
| ) |  |

Reads a string from wire and put in a DSTR.

On error we read the bytes from the wire anyway.

Parameters

  | tds | A pointer to the TDSSOCKET structure managing a client/server operation.
  [out] | s | output string
  [in] | len | string length (in characters)

Returns
  string or NULL on error

## § tds_flush_packet()

TDSRET tds_flush_packet | ( | TDSSOCKET * | tds | ) |

Flush packet to server.

Returns
  TDS_FAIL or TDS_SUCCESS

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## § tds_get_byte()

unsigned char tds_get_byte | ( | TDSSOCKET * | tds | ) |

Return a single byte from the input buffer.

Parameters

  tds | A pointer to the TDSSOCKET structure managing a client/server operation.

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## § tds_get_char_data()

TDSRET tds_get_char_data | ( | TDSSOCKET * | tds,
|  | char * | row_buffer,
|  | size_t | wire_size,
|  | TDSCOLUMN * | curcol
| ) |  |

Fetch character data the wire.

Output is NOT null terminated. If char_conv is not NULL, convert data accordingly.

Parameters

  tds | state information for the socket and the TDS protocol
  row_buffer | destination buffer in current_row. Can't be NULL
  wire_size | size to read from wire (in bytes)
  curcol | column information

Returns
  TDS_SUCCESS or TDS_FAIL (probably memory error on text data)

## § tds_get_n()

void* tds_get_n | ( | TDSSOCKET * | tds,
|  | void * | dest,
|  | size_t | need
| ) |  |

Get N bytes from the buffer and return them in the already allocated space given to us.

We ASSUME that the person calling this function has done the bounds checking for us since they know how many bytes they want here. dest of NULL means we just want to eat the bytes. (tethe.nosp@m.row@.nosp@m.nol.o.nosp@m.rg)

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## § tds_get_string()

size_t tds_get_string | ( | TDSSOCKET * | tds,
|  | size_t | string_len,
|  | char * | dest,
|  | size_t | dest_size
| ) |  |

Fetch a string from the wire.

Output string is NOT null terminated. If TDS version is 7 or 8 read unicode string and convert it. This function should be use to read server default encoding strings like columns name, table names, etc, not for data (use tds_get_char_data instead)

Returns
  bytes written to dest

Parameters

  tds | connection information
  string_len | length of string to read from wire (in server characters, bytes for tds4-tds5, ucs2 for tds7+)
  dest | destination buffer, if NULL string is read and discarded
  dest_size | destination buffer size, in bytes

## § tds_get_uint()

TDS_UINT tds_get_uint | ( | TDSSOCKET * | tds | ) |

Get an int32 from the server.

Parameters

  tds | A pointer to the TDSSOCKET structure managing a client/server operation.

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## § tds_get_uint8()

TDS_UINT8 tds_get_uint8 | ( | TDSSOCKET * | tds | ) |

Get an uint64 from the server.

Parameters

  tds | A pointer to the TDSSOCKET structure managing a client/server operation.

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## § tds_goodwrite()

int tds_goodwrite | ( | TDSSOCKET * | tds,
|  | const unsigned char * | buffer,
|  | size_t | buflen
| ) |  |

Parameters

  tds | the famous socket
  buffer | data to send
  buflen | bytes in buffer
  last | 1 if this is the last packet, else 0

Returns
  length written (>0), <0 on failure

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## § tds_peek()

unsigned char tds_peek | ( | TDSSOCKET * | tds | ) |

Reads a byte from the TDS stream without removing it.

Parameters

  tds | A pointer to the TDSSOCKET structure managing a client/server operation.

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## § tds_put_string()

int tds_put_string | ( | TDSSOCKET * | tds,
|  | const char * | s,
|  | int | len
| ) |  |

Output a string to wire automatic translate string to unicode if needed.

Returns
  bytes written to wire

Parameters

  tds | state information for the socket and the TDS protocol
  s | string to write
  len | length of string in characters, or -1 for null terminated

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## § tds_read_packet()

int tds_read_packet | ( | TDSSOCKET * | tds | ) |

Read in one 'packet' from the server.

This is a wrapped outer packet of the protocol (they bundle result packets into chunks and wrap them at what appears to be 512 bytes regardless of how that breaks internal packet up. (tetherow@nol.org)

Returns
  bytes read or -1 on failure

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## § tds_select()

int tds_select | ( | TDSSOCKET * | tds,
|  | unsigned | tds_sel,
|  | int | timeout_seconds
| ) |  |

Select on a socket until it's available or the timeout expires.

Meanwhile, call the interrupt function.

Returns
  >0 ready descriptors 0 timeout <0 error (cf. errno). Caller should close socket and return failure. This function does not call tdserror or close the socket because it can't know the context in which it's being called.

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## § tds_socket_read()

static int tds_socket_read | ( | TDSCONNECTION * | conn,
|  | TDSSOCKET * | tds,
|  | unsigned char * | buf,
|  | int | buflen
| ) |  |

static

Read from an OS socket remove tds, save error somewhere, report error in another way.

Returns
  0 if blocking, <0 error >0 bytes read

## § tds_socket_set_nonblocking()

int tds_socket_set_nonblocking | ( | TDS_SYS_SOCKET | sock | ) |

Set socket to non-blocking.

Parameters

  sock | socket to set

Returns
  0 on success or error code

## § tds_socket_write()

static int tds_socket_write | ( | TDSCONNECTION * | conn,
|  | TDSSOCKET * | tds,
|  | const unsigned char * | buf,
|  | int | buflen
| ) |  |

static

Write to an OS socket.

Returns
  0 if blocking, <0 error >0 bytes readed

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## § tds_unget_byte()

void tds_unget_byte | ( | TDSSOCKET * | tds | ) |

Unget will always work as long as you don't call it twice in a row.

It it may work if you call it multiple times as long as you don't backup over the beginning of network packet boundary which can occur anywhere in the token stream.

Parameters

  tds | A pointer to the TDSSOCKET structure managing a client/server operation.