libpq.h

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/*-------------------------------------------------------------------------
 *
 * libpq.h
 *    POSTGRES LIBPQ buffer structure definitions.
 *
 *
 * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/libpq/libpq.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef LIBPQ_H
#define LIBPQ_H

#include <netinet/in.h>

#include "lib/stringinfo.h"
#include "libpq/libpq-be.h"
#include "storage/latch.h"


/*
 * Callers of pq_getmessage() must supply a maximum expected message size.
 * By convention, if there's not any specific reason to use another value,
 * use PQ_SMALL_MESSAGE_LIMIT for messages that shouldn't be too long, and
 * PQ_LARGE_MESSAGE_LIMIT for messages that can be long.
 */
#define PQ_SMALL_MESSAGE_LIMIT  10000
#define PQ_LARGE_MESSAGE_LIMIT  (MaxAllocSize - 1)

typedef struct
{
    void        (*comm_reset) (void);
    int         (*flush) (void);
    int         (*flush_if_writable) (void);
    bool        (*is_send_pending) (void);
    int         (*putmessage) (char msgtype, const char *s, size_t len);
    void        (*putmessage_noblock) (char msgtype, const char *s, size_t len);
} PQcommMethods;

extern const PGDLLIMPORT PQcommMethods *PqCommMethods;

#define pq_comm_reset() (PqCommMethods->comm_reset())
#define pq_flush() (PqCommMethods->flush())
#define pq_flush_if_writable() (PqCommMethods->flush_if_writable())
#define pq_is_send_pending() (PqCommMethods->is_send_pending())
#define pq_putmessage(msgtype, s, len) \
    (PqCommMethods->putmessage(msgtype, s, len))
#define pq_putmessage_noblock(msgtype, s, len) \
    (PqCommMethods->putmessage_noblock(msgtype, s, len))

/*
 * External functions.
 */

/*
 * prototypes for functions in pqcomm.c
 */
extern WaitEventSet *FeBeWaitSet;

#define FeBeWaitSetSocketPos 0
#define FeBeWaitSetLatchPos 1

extern int  StreamServerPort(int family, const char *hostName,
                             unsigned short portNumber, const char *unixSocketDir,
                             pgsocket ListenSocket[], int MaxListen);
extern int  StreamConnection(pgsocket server_fd, Port *port);
extern void StreamClose(pgsocket sock);
extern void TouchSocketFiles(void);
extern void RemoveSocketFiles(void);
extern void pq_init(void);
extern int  pq_getbytes(char *s, size_t len);
extern void pq_startmsgread(void);
extern void pq_endmsgread(void);
extern bool pq_is_reading_msg(void);
extern int  pq_getmessage(StringInfo s, int maxlen);
extern int  pq_getbyte(void);
extern int  pq_peekbyte(void);
extern int  pq_getbyte_if_available(unsigned char *c);
extern int  pq_putmessage_v2(char msgtype, const char *s, size_t len);
extern bool pq_check_connection(void);

/*
 * prototypes for functions in be-secure.c
 */
extern char *ssl_library;
extern char *ssl_cert_file;
extern char *ssl_key_file;
extern char *ssl_ca_file;
extern char *ssl_crl_file;
extern char *ssl_crl_dir;
extern char *ssl_dh_params_file;
extern PGDLLIMPORT char *ssl_passphrase_command;
extern PGDLLIMPORT bool ssl_passphrase_command_supports_reload;
#ifdef USE_SSL
extern bool ssl_loaded_verify_locations;
#endif

extern int  secure_initialize(bool isServerStart);
extern bool secure_loaded_verify_locations(void);
extern void secure_destroy(void);
extern int  secure_open_server(Port *port);
extern void secure_close(Port *port);
extern ssize_t secure_read(Port *port, void *ptr, size_t len);
extern ssize_t secure_write(Port *port, void *ptr, size_t len);
extern ssize_t secure_raw_read(Port *port, void *ptr, size_t len);
extern ssize_t secure_raw_write(Port *port, const void *ptr, size_t len);

/*
 * prototypes for functions in be-secure-gssapi.c
 */
#ifdef ENABLE_GSS
extern ssize_t secure_open_gssapi(Port *port);
#endif

/* GUCs */
extern char *SSLCipherSuites;
extern char *SSLECDHCurve;
extern bool SSLPreferServerCiphers;
extern int  ssl_min_protocol_version;
extern int  ssl_max_protocol_version;

enum ssl_protocol_versions
{
    PG_TLS_ANY = 0,
    PG_TLS1_VERSION,
    PG_TLS1_1_VERSION,
    PG_TLS1_2_VERSION,
    PG_TLS1_3_VERSION,
};

/*
 * prototypes for functions in be-secure-common.c
 */
extern int  run_ssl_passphrase_command(const char *prompt, bool is_server_start,
                                       char *buf, int size);
extern bool check_ssl_key_file_permissions(const char *ssl_key_file,
                                           bool isServerStart);

#endif                          /* LIBPQ_H */