diff options
Diffstat (limited to 'src/backend/libpq/pqcomm.c')
| -rw-r--r-- | src/backend/libpq/pqcomm.c | 778 |
1 files changed, 0 insertions, 778 deletions
diff --git a/src/backend/libpq/pqcomm.c b/src/backend/libpq/pqcomm.c deleted file mode 100644 index dd9c6e75d21..00000000000 --- a/src/backend/libpq/pqcomm.c +++ /dev/null @@ -1,778 +0,0 @@ -/*------------------------------------------------------------------------- - * - * pqcomm.c - * Communication functions between the Frontend and the Backend - * - * These routines handle the low-level details of communication between - * frontend and backend. They just shove data across the communication - * channel, and are ignorant of the semantics of the data --- or would be, - * except for major brain damage in the design of the COPY OUT protocol. - * Unfortunately, COPY OUT is designed to commandeer the communication - * channel (it just transfers data without wrapping it into messages). - * No other messages can be sent while COPY OUT is in progress; and if the - * copy is aborted by an elog(ERROR), we need to close out the copy so that - * the frontend gets back into sync. Therefore, these routines have to be - * aware of COPY OUT state. - * - * NOTE: generally, it's a bad idea to emit outgoing messages directly with - * pq_putbytes(), especially if the message would require multiple calls - * to send. Instead, use the routines in pqformat.c to construct the message - * in a buffer and then emit it in one call to pq_putmessage. This helps - * ensure that the channel will not be clogged by an incomplete message - * if execution is aborted by elog(ERROR) partway through the message. - * The only non-libpq code that should call pq_putbytes directly is COPY OUT. - * - * At one time, libpq was shared between frontend and backend, but now - * the backend's "backend/libpq" is quite separate from "interfaces/libpq". - * All that remains is similarities of names to trap the unwary... - * - * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group - * Portions Copyright (c) 1994, Regents of the University of California - * - * $Id: pqcomm.c,v 1.137 2002/06/20 20:29:28 momjian Exp $ - * - *------------------------------------------------------------------------- - */ - -/*------------------------ - * INTERFACE ROUTINES - * - * setup/teardown: - * StreamServerPort - Open postmaster's server port - * StreamConnection - Create new connection with client - * StreamClose - Close a client/backend connection - * pq_init - initialize libpq at backend startup - * pq_close - shutdown libpq at backend exit - * - * low-level I/O: - * pq_getbytes - get a known number of bytes from connection - * pq_getstring - get a null terminated string from connection - * pq_getbyte - get next byte from connection - * pq_peekbyte - peek at next byte from connection - * pq_putbytes - send bytes to connection (not flushed until pq_flush) - * pq_flush - flush pending output - * - * message-level I/O (and COPY OUT cruft): - * pq_putmessage - send a normal message (suppressed in COPY OUT mode) - * pq_startcopyout - inform libpq that a COPY OUT transfer is beginning - * pq_endcopyout - end a COPY OUT transfer - * - *------------------------ - */ -#include "postgres.h" - -#include <signal.h> -#include <errno.h> -#include <fcntl.h> -#include <grp.h> -#include <unistd.h> -#include <sys/types.h> -#include <sys/stat.h> -#include <sys/socket.h> -#include <netdb.h> -#include <netinet/in.h> -#ifdef HAVE_NETINET_TCP_H -#include <netinet/tcp.h> -#endif -#include <arpa/inet.h> -#include <sys/file.h> - -#include "libpq/libpq.h" -#include "miscadmin.h" -#include "storage/ipc.h" - -extern void secure_close(Port *); -extern ssize_t secure_read(Port *, void *, size_t); -extern ssize_t secure_write(Port *, const void *, size_t); - -static void pq_close(void); - - -/* - * Configuration options - */ -int Unix_socket_permissions; -char *Unix_socket_group; - - -/* - * Buffers for low-level I/O - */ - -#define PQ_BUFFER_SIZE 8192 - -static unsigned char PqSendBuffer[PQ_BUFFER_SIZE]; -static int PqSendPointer; /* Next index to store a byte in - * PqSendBuffer */ - -static unsigned char PqRecvBuffer[PQ_BUFFER_SIZE]; -static int PqRecvPointer; /* Next index to read a byte from - * PqRecvBuffer */ -static int PqRecvLength; /* End of data available in PqRecvBuffer */ - -/* - * Message status - */ -static bool DoingCopyOut; - - -/* -------------------------------- - * pq_init - initialize libpq at backend startup - * -------------------------------- - */ -void -pq_init(void) -{ - PqSendPointer = PqRecvPointer = PqRecvLength = 0; - DoingCopyOut = false; - on_proc_exit(pq_close, 0); -} - - -/* -------------------------------- - * pq_close - shutdown libpq at backend exit - * - * Note: in a standalone backend MyProcPort will be null, - * don't crash during exit... - * -------------------------------- - */ -static void -pq_close(void) -{ - if (MyProcPort != NULL) - { - secure_close(MyProcPort); - close(MyProcPort->sock); - /* make sure any subsequent attempts to do I/O fail cleanly */ - MyProcPort->sock = -1; - } -} - - - -/* - * Streams -- wrapper around Unix socket system calls - * - * - * Stream functions are used for vanilla TCP connection protocol. - */ - -static char sock_path[MAXPGPATH]; - - -/* StreamDoUnlink() - * Shutdown routine for backend connection - * If a Unix socket is used for communication, explicitly close it. - */ -static void -StreamDoUnlink(void) -{ - Assert(sock_path[0]); - unlink(sock_path); -} - -/* - * StreamServerPort -- open a sock stream "listening" port. - * - * This initializes the Postmaster's connection-accepting port *fdP. - * - * RETURNS: STATUS_OK or STATUS_ERROR - */ - -int -StreamServerPort(int family, char *hostName, unsigned short portNumber, - char *unixSocketName, int *fdP) -{ - SockAddr saddr; - int fd, - err; - int maxconn; - size_t len = 0; - int one = 1; - - Assert(family == AF_INET || family == AF_UNIX); - - if ((fd = socket(family, SOCK_STREAM, 0)) < 0) - { - elog(LOG, "StreamServerPort: socket() failed: %m"); - return STATUS_ERROR; - } - - if (family == AF_INET) - { - if ((setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *) &one, - sizeof(one))) == -1) - { - elog(LOG, "StreamServerPort: setsockopt(SO_REUSEADDR) failed: %m"); - return STATUS_ERROR; - } - } - - MemSet((char *) &saddr, 0, sizeof(saddr)); - saddr.sa.sa_family = family; - -#ifdef HAVE_UNIX_SOCKETS - if (family == AF_UNIX) - { - UNIXSOCK_PATH(saddr.un, portNumber, unixSocketName); - len = UNIXSOCK_LEN(saddr.un); - strcpy(sock_path, saddr.un.sun_path); - - /* - * Grab an interlock file associated with the socket file. - */ - if (!CreateSocketLockFile(sock_path, true)) - return STATUS_ERROR; - - /* - * Once we have the interlock, we can safely delete any - * pre-existing socket file to avoid failure at bind() time. - */ - unlink(sock_path); - } -#endif /* HAVE_UNIX_SOCKETS */ - - if (family == AF_INET) - { - /* TCP/IP socket */ - if (hostName[0] == '\0') - saddr.in.sin_addr.s_addr = htonl(INADDR_ANY); - else - { - struct hostent *hp; - - hp = gethostbyname(hostName); - if ((hp == NULL) || (hp->h_addrtype != AF_INET)) - { - elog(LOG, "StreamServerPort: gethostbyname(%s) failed", - hostName); - return STATUS_ERROR; - } - memmove((char *) &(saddr.in.sin_addr), (char *) hp->h_addr, - hp->h_length); - } - - saddr.in.sin_port = htons(portNumber); - len = sizeof(struct sockaddr_in); - } - - err = bind(fd, (struct sockaddr *) & saddr.sa, len); - if (err < 0) - { - if (family == AF_UNIX) - elog(LOG, "StreamServerPort: bind() failed: %m\n" - "\tIs another postmaster already running on port %d?\n" - "\tIf not, remove socket node (%s) and retry.", - (int) portNumber, sock_path); - else - elog(LOG, "StreamServerPort: bind() failed: %m\n" - "\tIs another postmaster already running on port %d?\n" - "\tIf not, wait a few seconds and retry.", - (int) portNumber); - return STATUS_ERROR; - } - -#ifdef HAVE_UNIX_SOCKETS - if (family == AF_UNIX) - { - /* Arrange to unlink the socket file at exit */ - on_proc_exit(StreamDoUnlink, 0); - - /* - * Fix socket ownership/permission if requested. Note we must do - * this before we listen() to avoid a window where unwanted - * connections could get accepted. - */ - Assert(Unix_socket_group); - if (Unix_socket_group[0] != '\0') - { - char *endptr; - unsigned long int val; - gid_t gid; - - val = strtoul(Unix_socket_group, &endptr, 10); - if (*endptr == '\0') - { - /* numeric group id */ - gid = val; - } - else - { - /* convert group name to id */ - struct group *gr; - - gr = getgrnam(Unix_socket_group); - if (!gr) - { - elog(LOG, "No such group as '%s'", - Unix_socket_group); - return STATUS_ERROR; - } - gid = gr->gr_gid; - } - if (chown(sock_path, -1, gid) == -1) - { - elog(LOG, "Could not set group of %s: %m", - sock_path); - return STATUS_ERROR; - } - } - - if (chmod(sock_path, Unix_socket_permissions) == -1) - { - elog(LOG, "Could not set permissions on %s: %m", - sock_path); - return STATUS_ERROR; - } - } -#endif /* HAVE_UNIX_SOCKETS */ - - /* - * Select appropriate accept-queue length limit. PG_SOMAXCONN is only - * intended to provide a clamp on the request on platforms where an - * overly large request provokes a kernel error (are there any?). - */ - maxconn = MaxBackends * 2; - if (maxconn > PG_SOMAXCONN) - maxconn = PG_SOMAXCONN; - - err = listen(fd, maxconn); - if (err < 0) - { - elog(LOG, "StreamServerPort: listen() failed: %m"); - return STATUS_ERROR; - } - - *fdP = fd; - - return STATUS_OK; -} - -/* - * StreamConnection -- create a new connection with client using - * server port. - * - * ASSUME: that this doesn't need to be non-blocking because - * the Postmaster uses select() to tell when the server master - * socket is ready for accept(). - * - * RETURNS: STATUS_OK or STATUS_ERROR - */ -int -StreamConnection(int server_fd, Port *port) -{ - ACCEPT_TYPE_ARG3 addrlen; - - /* accept connection (and fill in the client (remote) address) */ - addrlen = sizeof(port->raddr); - if ((port->sock = accept(server_fd, - (struct sockaddr *) & port->raddr, - &addrlen)) < 0) - { - elog(LOG, "StreamConnection: accept() failed: %m"); - return STATUS_ERROR; - } - -#ifdef SCO_ACCEPT_BUG - - /* - * UnixWare 7+ and OpenServer 5.0.4 are known to have this bug, but it - * shouldn't hurt to catch it for all versions of those platforms. - */ - if (port->raddr.sa.sa_family == 0) - port->raddr.sa.sa_family = AF_UNIX; -#endif - - /* fill in the server (local) address */ - addrlen = sizeof(port->laddr); - if (getsockname(port->sock, (struct sockaddr *) & port->laddr, - &addrlen) < 0) - { - elog(LOG, "StreamConnection: getsockname() failed: %m"); - return STATUS_ERROR; - } - - /* select NODELAY and KEEPALIVE options if it's a TCP connection */ - if (port->laddr.sa.sa_family == AF_INET) - { - int on = 1; - - if (setsockopt(port->sock, IPPROTO_TCP, TCP_NODELAY, - (char *) &on, sizeof(on)) < 0) - { - elog(LOG, "StreamConnection: setsockopt(TCP_NODELAY) failed: %m"); - return STATUS_ERROR; - } - if (setsockopt(port->sock, SOL_SOCKET, SO_KEEPALIVE, - (char *) &on, sizeof(on)) < 0) - { - elog(LOG, "StreamConnection: setsockopt(SO_KEEPALIVE) failed: %m"); - return STATUS_ERROR; - } - } - - return STATUS_OK; -} - -/* - * StreamClose -- close a client/backend connection - */ -void -StreamClose(int sock) -{ - close(sock); -} - - -/* -------------------------------- - * Low-level I/O routines begin here. - * - * These routines communicate with a frontend client across a connection - * already established by the preceding routines. - * -------------------------------- - */ - - -/* -------------------------------- - * pq_recvbuf - load some bytes into the input buffer - * - * returns 0 if OK, EOF if trouble - * -------------------------------- - */ -static int -pq_recvbuf(void) -{ - if (PqRecvPointer > 0) - { - if (PqRecvLength > PqRecvPointer) - { - /* still some unread data, left-justify it in the buffer */ - memmove(PqRecvBuffer, PqRecvBuffer + PqRecvPointer, - PqRecvLength - PqRecvPointer); - PqRecvLength -= PqRecvPointer; - PqRecvPointer = 0; - } - else - PqRecvLength = PqRecvPointer = 0; - } - - /* Can fill buffer from PqRecvLength and upwards */ - for (;;) - { - int r; - - r = secure_read(MyProcPort, PqRecvBuffer + PqRecvLength, - PQ_BUFFER_SIZE - PqRecvLength); - - if (r < 0) - { - if (errno == EINTR) - continue; /* Ok if interrupted */ - - /* - * Careful: an elog() that tries to write to the client - * would cause recursion to here, leading to stack overflow - * and core dump! This message must go *only* to the postmaster - * log. - */ - elog(COMMERROR, "pq_recvbuf: recv() failed: %m"); - return EOF; - } - if (r == 0) - { - /* as above, only write to postmaster log */ - elog(COMMERROR, "pq_recvbuf: unexpected EOF on client connection"); - return EOF; - } - /* r contains number of bytes read, so just incr length */ - PqRecvLength += r; - return 0; - } -} - -/* -------------------------------- - * pq_getbyte - get a single byte from connection, or return EOF - * -------------------------------- - */ -int -pq_getbyte(void) -{ - while (PqRecvPointer >= PqRecvLength) - { - if (pq_recvbuf()) /* If nothing in buffer, then recv some */ - return EOF; /* Failed to recv data */ - } - return PqRecvBuffer[PqRecvPointer++]; -} - -/* -------------------------------- - * pq_peekbyte - peek at next byte from connection - * - * Same as pq_getbyte() except we don't advance the pointer. - * -------------------------------- - */ -int -pq_peekbyte(void) -{ - while (PqRecvPointer >= PqRecvLength) - { - if (pq_recvbuf()) /* If nothing in buffer, then recv some */ - return EOF; /* Failed to recv data */ - } - return PqRecvBuffer[PqRecvPointer]; -} - -/* -------------------------------- - * pq_getbytes - get a known number of bytes from connection - * - * returns 0 if OK, EOF if trouble - * -------------------------------- - */ -int -pq_getbytes(char *s, size_t len) -{ - size_t amount; - - while (len > 0) - { - while (PqRecvPointer >= PqRecvLength) - { - if (pq_recvbuf()) /* If nothing in buffer, then recv some */ - return EOF; /* Failed to recv data */ - } - amount = PqRecvLength - PqRecvPointer; - if (amount > len) - amount = len; - memcpy(s, PqRecvBuffer + PqRecvPointer, amount); - PqRecvPointer += amount; - s += amount; - len -= amount; - } - return 0; -} - -/* -------------------------------- - * pq_getstring - get a null terminated string from connection - * - * The return value is placed in an expansible StringInfo. - * Note that space allocation comes from the current memory context! - * - * NOTE: this routine does not do any MULTIBYTE conversion, - * even though it is presumably useful only for text, because - * no code in this module should depend on MULTIBYTE mode. - * See pq_getstr in pqformat.c for that. - * - * returns 0 if OK, EOF if trouble - * -------------------------------- - */ -int -pq_getstring(StringInfo s) -{ - int i; - - /* Reset string to empty */ - s->len = 0; - s->data[0] = '\0'; - - /* Read until we get the terminating '\0' */ - for(;;) - { - while (PqRecvPointer >= PqRecvLength) - { - if (pq_recvbuf()) /* If nothing in buffer, then recv some */ - return EOF; /* Failed to recv data */ - } - - for (i = PqRecvPointer; i < PqRecvLength; i++) - { - if (PqRecvBuffer[i] == '\0') - { - /* does not copy the \0 */ - appendBinaryStringInfo(s, PqRecvBuffer + PqRecvPointer, - i - PqRecvPointer); - PqRecvPointer = i + 1; /* advance past \0 */ - return 0; - } - } - - /* If we're here we haven't got the \0 in the buffer yet. */ - - appendBinaryStringInfo(s, PqRecvBuffer + PqRecvPointer, - PqRecvLength - PqRecvPointer); - PqRecvPointer = PqRecvLength; - } -} - - -/* -------------------------------- - * pq_putbytes - send bytes to connection (not flushed until pq_flush) - * - * returns 0 if OK, EOF if trouble - * -------------------------------- - */ -int -pq_putbytes(const char *s, size_t len) -{ - size_t amount; - - while (len > 0) - { - if (PqSendPointer >= PQ_BUFFER_SIZE) - if (pq_flush()) /* If buffer is full, then flush it out */ - return EOF; - amount = PQ_BUFFER_SIZE - PqSendPointer; - if (amount > len) - amount = len; - memcpy(PqSendBuffer + PqSendPointer, s, amount); - PqSendPointer += amount; - s += amount; - len -= amount; - } - return 0; -} - -/* -------------------------------- - * pq_flush - flush pending output - * - * returns 0 if OK, EOF if trouble - * -------------------------------- - */ -int -pq_flush(void) -{ - static int last_reported_send_errno = 0; - - unsigned char *bufptr = PqSendBuffer; - unsigned char *bufend = PqSendBuffer + PqSendPointer; - - while (bufptr < bufend) - { - int r; - - r = secure_write(MyProcPort, bufptr, bufend - bufptr); - - if (r <= 0) - { - if (errno == EINTR) - continue; /* Ok if we were interrupted */ - - /* - * Careful: an elog() that tries to write to the client - * would cause recursion to here, leading to stack overflow - * and core dump! This message must go *only* to the postmaster - * log. - * - * If a client disconnects while we're in the midst of output, - * we might write quite a bit of data before we get to a safe - * query abort point. So, suppress duplicate log messages. - */ - if (errno != last_reported_send_errno) - { - last_reported_send_errno = errno; - elog(COMMERROR, "pq_flush: send() failed: %m"); - } - - /* - * We drop the buffered data anyway so that processing can - * continue, even though we'll probably quit soon. - */ - PqSendPointer = 0; - return EOF; - } - - last_reported_send_errno = 0; /* reset after any successful send */ - bufptr += r; - } - - PqSendPointer = 0; - return 0; -} - - -/* - * Return EOF if the connection has been broken, else 0. - */ -int -pq_eof(void) -{ - char x; - int res; - - res = recv(MyProcPort->sock, &x, 1, MSG_PEEK); - - if (res < 0) - { - /* can log to postmaster log only */ - elog(COMMERROR, "pq_eof: recv() failed: %m"); - return EOF; - } - if (res == 0) - return EOF; - else - return 0; -} - - -/* -------------------------------- - * Message-level I/O routines begin here. - * - * These routines understand about COPY OUT protocol. - * -------------------------------- - */ - - -/* -------------------------------- - * pq_putmessage - send a normal message (suppressed in COPY OUT mode) - * - * If msgtype is not '\0', it is a message type code to place before - * the message body (len counts only the body size!). - * If msgtype is '\0', then the buffer already includes the type code. - * - * All normal messages are suppressed while COPY OUT is in progress. - * (In practice only a few messages might get emitted then; dropping - * them is annoying, but at least they will still appear in the - * postmaster log.) - * - * returns 0 if OK, EOF if trouble - * -------------------------------- - */ -int -pq_putmessage(char msgtype, const char *s, size_t len) -{ - if (DoingCopyOut) - return 0; - if (msgtype) - if (pq_putbytes(&msgtype, 1)) - return EOF; - return pq_putbytes(s, len); -} - -/* -------------------------------- - * pq_startcopyout - inform libpq that a COPY OUT transfer is beginning - * -------------------------------- - */ -void -pq_startcopyout(void) -{ - DoingCopyOut = true; -} - -/* -------------------------------- - * pq_endcopyout - end a COPY OUT transfer - * - * If errorAbort is indicated, we are aborting a COPY OUT due to an error, - * and must send a terminator line. Since a partial data line might have - * been emitted, send a couple of newlines first (the first one could - * get absorbed by a backslash...) - * -------------------------------- - */ -void -pq_endcopyout(bool errorAbort) -{ - if (!DoingCopyOut) - return; - if (errorAbort) - pq_putbytes("\n\n\\.\n", 5); - /* in non-error case, copy.c will have emitted the terminator line */ - DoingCopyOut = false; -} |