libpq.h

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/*-------------------------------------------------------------------------
 *
 * libpq.h
 *    POSTGRES LIBPQ buffer structure definitions.
 *
 *
 * Portions Copyright (c) 1996-2026, 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"
 
 
/* avoid including waiteventset.h */
typedef struct WaitEventSet WaitEventSet;
 
 
/*
 * 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 PGDLLIMPORT WaitEventSet *FeBeWaitSet;
 
#define FeBeWaitSetSocketPos 0
#define FeBeWaitSetLatchPos 1
#define FeBeWaitSetNEvents 3
 
extern int  ListenServerPort(int family, const char *hostName,
                             unsigned short portNumber, const char *unixSocketDir,
                             pgsocket ListenSockets[], int *NumListenSockets, int MaxListen);
extern int  AcceptConnection(pgsocket server_fd, ClientSocket *client_sock);
extern void TouchSocketFiles(void);
extern void RemoveSocketFiles(void);
extern Port *pq_init(ClientSocket *client_sock);
extern int  pq_getbytes(void *b, 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 ssize_t pq_buffer_remaining_data(void);
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 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, const 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);
 
/*
 * declarations for variables defined in be-secure.c
 */
extern PGDLLIMPORT char *ssl_library;
extern PGDLLIMPORT char *ssl_ca_file;
extern PGDLLIMPORT char *ssl_cert_file;
extern PGDLLIMPORT char *ssl_crl_file;
extern PGDLLIMPORT char *ssl_crl_dir;
extern PGDLLIMPORT char *ssl_key_file;
extern PGDLLIMPORT int ssl_min_protocol_version;
extern PGDLLIMPORT int ssl_max_protocol_version;
extern PGDLLIMPORT char *ssl_passphrase_command;
extern PGDLLIMPORT bool ssl_passphrase_command_supports_reload;
extern PGDLLIMPORT char *ssl_dh_params_file;
extern PGDLLIMPORT char *SSLCipherSuites;
extern PGDLLIMPORT char *SSLCipherList;
extern PGDLLIMPORT char *SSLECDHCurve;
extern PGDLLIMPORT bool SSLPreferServerCiphers;
#ifdef USE_SSL
extern PGDLLIMPORT bool ssl_loaded_verify_locations;
#endif
 
#ifdef USE_SSL
#define SSL_LIBRARY "OpenSSL"
#else
#define SSL_LIBRARY ""
#endif
 
#ifdef USE_OPENSSL
#define DEFAULT_SSL_CIPHERS "HIGH:MEDIUM:+3DES:!aNULL"
#else
#define DEFAULT_SSL_CIPHERS "none"
#endif
 
#ifdef USE_SSL
#define DEFAULT_SSL_GROUPS "X25519:prime256v1"
#else
#define DEFAULT_SSL_GROUPS "none"
#endif
 
/*
 * prototypes for functions in be-secure-gssapi.c
 */
#ifdef ENABLE_GSS
extern ssize_t secure_open_gssapi(Port *port);
#endif
 
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 */