mirror of
https://git.postgresql.org/git/postgresql.git
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1109 lines
26 KiB
C
1109 lines
26 KiB
C
/*-------------------------------------------------------------------------
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*
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* FILE
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* fe-misc.c
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*
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* DESCRIPTION
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* miscellaneous useful functions
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*
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* The communication routines here are analogous to the ones in
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* backend/libpq/pqcomm.c and backend/libpq/pqcomprim.c, but operate
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* in the considerably different environment of the frontend libpq.
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* In particular, we work with a bare nonblock-mode socket, rather than
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* a stdio stream, so that we can avoid unwanted blocking of the application.
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*
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* XXX: MOVE DEBUG PRINTOUT TO HIGHER LEVEL. As is, block and restart
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* will cause repeat printouts.
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*
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* We must speak the same transmitted data representations as the backend
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* routines.
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*
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*
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* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-misc.c,v 1.94 2003/06/12 08:11:07 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres_fe.h"
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#include <errno.h>
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#include <signal.h>
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#include <time.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#ifdef WIN32
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#include "win32.h"
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#else
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#include <unistd.h>
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#include <sys/time.h>
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#endif
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#ifdef HAVE_POLL_H
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#include <poll.h>
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#endif
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#ifdef HAVE_SYS_POLL_H
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#include <sys/poll.h>
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#endif
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#ifdef HAVE_SYS_SELECT_H
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#include <sys/select.h>
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#endif
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#include "libpq-fe.h"
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#include "libpq-int.h"
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#include "pqsignal.h"
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#include "mb/pg_wchar.h"
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static int pqPutMsgBytes(const void *buf, size_t len, PGconn *conn);
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static int pqSendSome(PGconn *conn, int len);
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static int pqSocketCheck(PGconn *conn, int forRead, int forWrite,
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time_t end_time);
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static int pqSocketPoll(int sock, int forRead, int forWrite, time_t end_time);
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/*
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* pqGetc: get 1 character from the connection
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*
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* All these routines return 0 on success, EOF on error.
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* Note that for the Get routines, EOF only means there is not enough
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* data in the buffer, not that there is necessarily a hard error.
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*/
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int
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pqGetc(char *result, PGconn *conn)
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{
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if (conn->inCursor >= conn->inEnd)
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return EOF;
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*result = conn->inBuffer[conn->inCursor++];
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if (conn->Pfdebug)
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fprintf(conn->Pfdebug, "From backend> %c\n", *result);
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return 0;
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}
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/*
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* pqPutc: write 1 char to the current message
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*/
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int
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pqPutc(char c, PGconn *conn)
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{
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if (pqPutMsgBytes(&c, 1, conn))
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return EOF;
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if (conn->Pfdebug)
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fprintf(conn->Pfdebug, "To backend> %c\n", c);
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return 0;
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}
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/*
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* pqGets:
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* get a null-terminated string from the connection,
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* and store it in an expansible PQExpBuffer.
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* If we run out of memory, all of the string is still read,
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* but the excess characters are silently discarded.
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*/
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int
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pqGets(PQExpBuffer buf, PGconn *conn)
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{
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/* Copy conn data to locals for faster search loop */
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char *inBuffer = conn->inBuffer;
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int inCursor = conn->inCursor;
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int inEnd = conn->inEnd;
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int slen;
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while (inCursor < inEnd && inBuffer[inCursor])
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inCursor++;
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if (inCursor >= inEnd)
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return EOF;
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slen = inCursor - conn->inCursor;
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resetPQExpBuffer(buf);
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appendBinaryPQExpBuffer(buf, inBuffer + conn->inCursor, slen);
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conn->inCursor = ++inCursor;
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if (conn->Pfdebug)
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fprintf(conn->Pfdebug, "From backend> \"%s\"\n",
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buf->data);
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return 0;
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}
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/*
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* pqPuts: write a null-terminated string to the current message
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*/
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int
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pqPuts(const char *s, PGconn *conn)
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{
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if (pqPutMsgBytes(s, strlen(s) + 1, conn))
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return EOF;
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if (conn->Pfdebug)
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fprintf(conn->Pfdebug, "To backend> '%s'\n", s);
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return 0;
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}
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/*
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* pqGetnchar:
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* get a string of exactly len bytes in buffer s, no null termination
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*/
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int
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pqGetnchar(char *s, size_t len, PGconn *conn)
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{
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if (len < 0 || len > (size_t) (conn->inEnd - conn->inCursor))
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return EOF;
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memcpy(s, conn->inBuffer + conn->inCursor, len);
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/* no terminating null */
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conn->inCursor += len;
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if (conn->Pfdebug)
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fprintf(conn->Pfdebug, "From backend (%lu)> %.*s\n", (unsigned long) len, (int) len, s);
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return 0;
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}
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/*
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* pqPutnchar:
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* write exactly len bytes to the current message
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*/
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int
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pqPutnchar(const char *s, size_t len, PGconn *conn)
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{
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if (pqPutMsgBytes(s, len, conn))
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return EOF;
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if (conn->Pfdebug)
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fprintf(conn->Pfdebug, "To backend> %.*s\n", (int) len, s);
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return 0;
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}
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/*
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* pgGetInt
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* read a 2 or 4 byte integer and convert from network byte order
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* to local byte order
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*/
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int
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pqGetInt(int *result, size_t bytes, PGconn *conn)
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{
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uint16 tmp2;
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uint32 tmp4;
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char noticeBuf[64];
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switch (bytes)
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{
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case 2:
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if (conn->inCursor + 2 > conn->inEnd)
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return EOF;
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memcpy(&tmp2, conn->inBuffer + conn->inCursor, 2);
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conn->inCursor += 2;
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*result = (int) ntohs(tmp2);
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break;
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case 4:
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if (conn->inCursor + 4 > conn->inEnd)
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return EOF;
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memcpy(&tmp4, conn->inBuffer + conn->inCursor, 4);
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conn->inCursor += 4;
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*result = (int) ntohl(tmp4);
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break;
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default:
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snprintf(noticeBuf, sizeof(noticeBuf),
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libpq_gettext("integer of size %lu not supported by pqGetInt\n"),
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(unsigned long) bytes);
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PGDONOTICE(conn, noticeBuf);
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return EOF;
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}
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if (conn->Pfdebug)
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fprintf(conn->Pfdebug, "From backend (#%lu)> %d\n", (unsigned long) bytes, *result);
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return 0;
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}
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/*
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* pgPutInt
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* write an integer of 2 or 4 bytes, converting from host byte order
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* to network byte order.
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*/
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int
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pqPutInt(int value, size_t bytes, PGconn *conn)
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{
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uint16 tmp2;
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uint32 tmp4;
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char noticeBuf[64];
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switch (bytes)
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{
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case 2:
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tmp2 = htons((uint16) value);
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if (pqPutMsgBytes((const char *) &tmp2, 2, conn))
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return EOF;
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break;
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case 4:
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tmp4 = htonl((uint32) value);
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if (pqPutMsgBytes((const char *) &tmp4, 4, conn))
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return EOF;
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break;
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default:
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snprintf(noticeBuf, sizeof(noticeBuf),
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libpq_gettext("integer of size %lu not supported by pqPutInt\n"),
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(unsigned long) bytes);
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PGDONOTICE(conn, noticeBuf);
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return EOF;
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}
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if (conn->Pfdebug)
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fprintf(conn->Pfdebug, "To backend (%lu#)> %d\n", (unsigned long) bytes, value);
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return 0;
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}
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/*
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* Make sure conn's output buffer can hold bytes_needed bytes (caller must
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* include already-stored data into the value!)
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*
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* Returns 0 on success, EOF if failed to enlarge buffer
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*/
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static int
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pqCheckOutBufferSpace(int bytes_needed, PGconn *conn)
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{
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int newsize = conn->outBufSize;
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char *newbuf;
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if (bytes_needed <= newsize)
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return 0;
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/*
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* If we need to enlarge the buffer, we first try to double it in size;
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* if that doesn't work, enlarge in multiples of 8K. This avoids
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* thrashing the malloc pool by repeated small enlargements.
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*
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* Note: tests for newsize > 0 are to catch integer overflow.
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*/
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do {
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newsize *= 2;
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} while (bytes_needed > newsize && newsize > 0);
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if (bytes_needed <= newsize)
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{
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newbuf = realloc(conn->outBuffer, newsize);
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if (newbuf)
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{
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/* realloc succeeded */
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conn->outBuffer = newbuf;
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conn->outBufSize = newsize;
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return 0;
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}
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}
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newsize = conn->outBufSize;
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do {
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newsize += 8192;
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} while (bytes_needed > newsize && newsize > 0);
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if (bytes_needed <= newsize)
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{
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newbuf = realloc(conn->outBuffer, newsize);
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if (newbuf)
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{
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/* realloc succeeded */
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conn->outBuffer = newbuf;
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conn->outBufSize = newsize;
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return 0;
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}
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}
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/* realloc failed. Probably out of memory */
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printfPQExpBuffer(&conn->errorMessage,
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"cannot allocate memory for output buffer\n");
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return EOF;
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}
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/*
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* Make sure conn's input buffer can hold bytes_needed bytes (caller must
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* include already-stored data into the value!)
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*
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* Returns 0 on success, EOF if failed to enlarge buffer
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*/
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int
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pqCheckInBufferSpace(int bytes_needed, PGconn *conn)
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{
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int newsize = conn->inBufSize;
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char *newbuf;
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if (bytes_needed <= newsize)
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return 0;
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/*
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* If we need to enlarge the buffer, we first try to double it in size;
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* if that doesn't work, enlarge in multiples of 8K. This avoids
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* thrashing the malloc pool by repeated small enlargements.
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*
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* Note: tests for newsize > 0 are to catch integer overflow.
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*/
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do {
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newsize *= 2;
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} while (bytes_needed > newsize && newsize > 0);
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if (bytes_needed <= newsize)
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{
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newbuf = realloc(conn->inBuffer, newsize);
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if (newbuf)
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{
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/* realloc succeeded */
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conn->inBuffer = newbuf;
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conn->inBufSize = newsize;
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return 0;
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}
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}
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newsize = conn->inBufSize;
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do {
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newsize += 8192;
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} while (bytes_needed > newsize && newsize > 0);
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if (bytes_needed <= newsize)
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{
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newbuf = realloc(conn->inBuffer, newsize);
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if (newbuf)
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{
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/* realloc succeeded */
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conn->inBuffer = newbuf;
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conn->inBufSize = newsize;
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return 0;
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}
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}
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/* realloc failed. Probably out of memory */
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printfPQExpBuffer(&conn->errorMessage,
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"cannot allocate memory for input buffer\n");
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return EOF;
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}
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/*
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* pqPutMsgStart: begin construction of a message to the server
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*
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* msg_type is the message type byte, or 0 for a message without type byte
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* (only startup messages have no type byte)
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*
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* force_len forces the message to have a length word; otherwise, we add
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* a length word if protocol 3.
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*
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* Returns 0 on success, EOF on error
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*
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* The idea here is that we construct the message in conn->outBuffer,
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* beginning just past any data already in outBuffer (ie, at
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* outBuffer+outCount). We enlarge the buffer as needed to hold the message.
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* When the message is complete, we fill in the length word (if needed) and
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* then advance outCount past the message, making it eligible to send.
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*
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* The state variable conn->outMsgStart points to the incomplete message's
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* length word: it is either outCount or outCount+1 depending on whether
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* there is a type byte. If we are sending a message without length word
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* (pre protocol 3.0 only), then outMsgStart is -1. The state variable
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* conn->outMsgEnd is the end of the data collected so far.
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*/
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int
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pqPutMsgStart(char msg_type, bool force_len, PGconn *conn)
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{
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int lenPos;
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int endPos;
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/* allow room for message type byte */
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if (msg_type)
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endPos = conn->outCount + 1;
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else
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endPos = conn->outCount;
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|
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/* do we want a length word? */
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if (force_len || PG_PROTOCOL_MAJOR(conn->pversion) >= 3)
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{
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lenPos = endPos;
|
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/* allow room for message length */
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endPos += 4;
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}
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else
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{
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lenPos = -1;
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}
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|
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/* make sure there is room for message header */
|
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if (pqCheckOutBufferSpace(endPos, conn))
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return EOF;
|
|
/* okay, save the message type byte if any */
|
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if (msg_type)
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conn->outBuffer[conn->outCount] = msg_type;
|
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/* set up the message pointers */
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conn->outMsgStart = lenPos;
|
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conn->outMsgEnd = endPos;
|
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/* length word, if needed, will be filled in by pqPutMsgEnd */
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|
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if (conn->Pfdebug)
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fprintf(conn->Pfdebug, "To backend> Msg %c\n",
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msg_type ? msg_type : ' ');
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return 0;
|
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}
|
|
|
|
/*
|
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* pqPutMsgBytes: add bytes to a partially-constructed message
|
|
*
|
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* Returns 0 on success, EOF on error
|
|
*/
|
|
static int
|
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pqPutMsgBytes(const void *buf, size_t len, PGconn *conn)
|
|
{
|
|
/* make sure there is room for it */
|
|
if (pqCheckOutBufferSpace(conn->outMsgEnd + len, conn))
|
|
return EOF;
|
|
/* okay, save the data */
|
|
memcpy(conn->outBuffer + conn->outMsgEnd, buf, len);
|
|
conn->outMsgEnd += len;
|
|
/* no Pfdebug call here, caller should do it */
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* pqPutMsgEnd: finish constructing a message and possibly send it
|
|
*
|
|
* Returns 0 on success, EOF on error
|
|
*
|
|
* We don't actually send anything here unless we've accumulated at least
|
|
* 8K worth of data (the typical size of a pipe buffer on Unix systems).
|
|
* This avoids sending small partial packets. The caller must use pqFlush
|
|
* when it's important to flush all the data out to the server.
|
|
*/
|
|
int
|
|
pqPutMsgEnd(PGconn *conn)
|
|
{
|
|
if (conn->Pfdebug)
|
|
fprintf(conn->Pfdebug, "To backend> Msg complete, length %u\n",
|
|
conn->outMsgEnd - conn->outCount);
|
|
|
|
/* Fill in length word if needed */
|
|
if (conn->outMsgStart >= 0)
|
|
{
|
|
uint32 msgLen = conn->outMsgEnd - conn->outMsgStart;
|
|
|
|
msgLen = htonl(msgLen);
|
|
memcpy(conn->outBuffer + conn->outMsgStart, &msgLen, 4);
|
|
}
|
|
|
|
/* Make message eligible to send */
|
|
conn->outCount = conn->outMsgEnd;
|
|
|
|
if (conn->outCount >= 8192)
|
|
{
|
|
int toSend = conn->outCount - (conn->outCount % 8192);
|
|
|
|
if (pqSendSome(conn, toSend) < 0)
|
|
return EOF;
|
|
/* in nonblock mode, don't complain if unable to send it all */
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* ----------
|
|
* pqReadData: read more data, if any is available
|
|
* Possible return values:
|
|
* 1: successfully loaded at least one more byte
|
|
* 0: no data is presently available, but no error detected
|
|
* -1: error detected (including EOF = connection closure);
|
|
* conn->errorMessage set
|
|
* NOTE: callers must not assume that pointers or indexes into conn->inBuffer
|
|
* remain valid across this call!
|
|
* ----------
|
|
*/
|
|
int
|
|
pqReadData(PGconn *conn)
|
|
{
|
|
int someread = 0;
|
|
int nread;
|
|
|
|
if (conn->sock < 0)
|
|
{
|
|
printfPQExpBuffer(&conn->errorMessage,
|
|
libpq_gettext("connection not open\n"));
|
|
return -1;
|
|
}
|
|
|
|
/* Left-justify any data in the buffer to make room */
|
|
if (conn->inStart < conn->inEnd)
|
|
{
|
|
if (conn->inStart > 0)
|
|
{
|
|
memmove(conn->inBuffer, conn->inBuffer + conn->inStart,
|
|
conn->inEnd - conn->inStart);
|
|
conn->inEnd -= conn->inStart;
|
|
conn->inCursor -= conn->inStart;
|
|
conn->inStart = 0;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* buffer is logically empty, reset it */
|
|
conn->inStart = conn->inCursor = conn->inEnd = 0;
|
|
}
|
|
|
|
/*
|
|
* If the buffer is fairly full, enlarge it. We need to be able to
|
|
* enlarge the buffer in case a single message exceeds the initial
|
|
* buffer size. We enlarge before filling the buffer entirely so as
|
|
* to avoid asking the kernel for a partial packet. The magic constant
|
|
* here should be large enough for a TCP packet or Unix pipe
|
|
* bufferload. 8K is the usual pipe buffer size, so...
|
|
*/
|
|
if (conn->inBufSize - conn->inEnd < 8192)
|
|
{
|
|
if (pqCheckInBufferSpace(conn->inEnd + 8192, conn))
|
|
{
|
|
/*
|
|
* We don't insist that the enlarge worked, but we need some room
|
|
*/
|
|
if (conn->inBufSize - conn->inEnd < 100)
|
|
return -1; /* errorMessage already set */
|
|
}
|
|
}
|
|
|
|
/* OK, try to read some data */
|
|
retry3:
|
|
nread = pqsecure_read(conn, conn->inBuffer + conn->inEnd,
|
|
conn->inBufSize - conn->inEnd);
|
|
if (nread < 0)
|
|
{
|
|
if (SOCK_ERRNO == EINTR)
|
|
goto retry3;
|
|
/* Some systems return EAGAIN/EWOULDBLOCK for no data */
|
|
#ifdef EAGAIN
|
|
if (SOCK_ERRNO == EAGAIN)
|
|
return someread;
|
|
#endif
|
|
#if defined(EWOULDBLOCK) && (!defined(EAGAIN) || (EWOULDBLOCK != EAGAIN))
|
|
if (SOCK_ERRNO == EWOULDBLOCK)
|
|
return someread;
|
|
#endif
|
|
/* We might get ECONNRESET here if using TCP and backend died */
|
|
#ifdef ECONNRESET
|
|
if (SOCK_ERRNO == ECONNRESET)
|
|
goto definitelyFailed;
|
|
#endif
|
|
printfPQExpBuffer(&conn->errorMessage,
|
|
libpq_gettext("could not receive data from server: %s\n"),
|
|
SOCK_STRERROR(SOCK_ERRNO));
|
|
return -1;
|
|
}
|
|
if (nread > 0)
|
|
{
|
|
conn->inEnd += nread;
|
|
|
|
/*
|
|
* Hack to deal with the fact that some kernels will only give us
|
|
* back 1 packet per recv() call, even if we asked for more and
|
|
* there is more available. If it looks like we are reading a
|
|
* long message, loop back to recv() again immediately, until we
|
|
* run out of data or buffer space. Without this, the
|
|
* block-and-restart behavior of libpq's higher levels leads to
|
|
* O(N^2) performance on long messages.
|
|
*
|
|
* Since we left-justified the data above, conn->inEnd gives the
|
|
* amount of data already read in the current message. We
|
|
* consider the message "long" once we have acquired 32k ...
|
|
*/
|
|
if (conn->inEnd > 32768 &&
|
|
(conn->inBufSize - conn->inEnd) >= 8192)
|
|
{
|
|
someread = 1;
|
|
goto retry3;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
if (someread)
|
|
return 1; /* got a zero read after successful tries */
|
|
|
|
/*
|
|
* A return value of 0 could mean just that no data is now available,
|
|
* or it could mean EOF --- that is, the server has closed the
|
|
* connection. Since we have the socket in nonblock mode, the only way
|
|
* to tell the difference is to see if select() is saying that the
|
|
* file is ready. Grumble. Fortunately, we don't expect this path to
|
|
* be taken much, since in normal practice we should not be trying to
|
|
* read data unless the file selected for reading already.
|
|
*/
|
|
switch (pqReadReady(conn))
|
|
{
|
|
case 0:
|
|
/* definitely no data available */
|
|
return 0;
|
|
case 1:
|
|
/* ready for read */
|
|
break;
|
|
default:
|
|
goto definitelyFailed;
|
|
}
|
|
|
|
/*
|
|
* Still not sure that it's EOF, because some data could have just
|
|
* arrived.
|
|
*/
|
|
retry4:
|
|
nread = pqsecure_read(conn, conn->inBuffer + conn->inEnd,
|
|
conn->inBufSize - conn->inEnd);
|
|
if (nread < 0)
|
|
{
|
|
if (SOCK_ERRNO == EINTR)
|
|
goto retry4;
|
|
/* Some systems return EAGAIN/EWOULDBLOCK for no data */
|
|
#ifdef EAGAIN
|
|
if (SOCK_ERRNO == EAGAIN)
|
|
return 0;
|
|
#endif
|
|
#if defined(EWOULDBLOCK) && (!defined(EAGAIN) || (EWOULDBLOCK != EAGAIN))
|
|
if (SOCK_ERRNO == EWOULDBLOCK)
|
|
return 0;
|
|
#endif
|
|
/* We might get ECONNRESET here if using TCP and backend died */
|
|
#ifdef ECONNRESET
|
|
if (SOCK_ERRNO == ECONNRESET)
|
|
goto definitelyFailed;
|
|
#endif
|
|
printfPQExpBuffer(&conn->errorMessage,
|
|
libpq_gettext("could not receive data from server: %s\n"),
|
|
SOCK_STRERROR(SOCK_ERRNO));
|
|
return -1;
|
|
}
|
|
if (nread > 0)
|
|
{
|
|
conn->inEnd += nread;
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* OK, we are getting a zero read even though select() says ready.
|
|
* This means the connection has been closed. Cope.
|
|
*/
|
|
definitelyFailed:
|
|
printfPQExpBuffer(&conn->errorMessage,
|
|
libpq_gettext(
|
|
"server closed the connection unexpectedly\n"
|
|
"\tThis probably means the server terminated abnormally\n"
|
|
"\tbefore or while processing the request.\n"));
|
|
conn->status = CONNECTION_BAD; /* No more connection to backend */
|
|
pqsecure_close(conn);
|
|
closesocket(conn->sock);
|
|
conn->sock = -1;
|
|
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
* pqSendSome: send data waiting in the output buffer.
|
|
*
|
|
* len is how much to try to send (typically equal to outCount, but may
|
|
* be less).
|
|
*
|
|
* Return 0 on success, -1 on failure and 1 when not all data could be sent
|
|
* because the socket would block and the connection is non-blocking.
|
|
*/
|
|
static int
|
|
pqSendSome(PGconn *conn, int len)
|
|
{
|
|
char *ptr = conn->outBuffer;
|
|
int remaining = conn->outCount;
|
|
int result = 0;
|
|
|
|
if (conn->sock < 0)
|
|
{
|
|
printfPQExpBuffer(&conn->errorMessage,
|
|
libpq_gettext("connection not open\n"));
|
|
return -1;
|
|
}
|
|
|
|
/* while there's still data to send */
|
|
while (len > 0)
|
|
{
|
|
int sent;
|
|
|
|
sent = pqsecure_write(conn, ptr, len);
|
|
|
|
if (sent < 0)
|
|
{
|
|
/*
|
|
* Anything except EAGAIN or EWOULDBLOCK is trouble. If it's
|
|
* EPIPE or ECONNRESET, assume we've lost the backend
|
|
* connection permanently.
|
|
*/
|
|
switch (SOCK_ERRNO)
|
|
{
|
|
#ifdef EAGAIN
|
|
case EAGAIN:
|
|
break;
|
|
#endif
|
|
#if defined(EWOULDBLOCK) && (!defined(EAGAIN) || (EWOULDBLOCK != EAGAIN))
|
|
case EWOULDBLOCK:
|
|
break;
|
|
#endif
|
|
case EINTR:
|
|
continue;
|
|
|
|
case EPIPE:
|
|
#ifdef ECONNRESET
|
|
case ECONNRESET:
|
|
#endif
|
|
printfPQExpBuffer(&conn->errorMessage,
|
|
libpq_gettext(
|
|
"server closed the connection unexpectedly\n"
|
|
"\tThis probably means the server terminated abnormally\n"
|
|
"\tbefore or while processing the request.\n"));
|
|
|
|
/*
|
|
* We used to close the socket here, but that's a bad
|
|
* idea since there might be unread data waiting
|
|
* (typically, a NOTICE message from the backend
|
|
* telling us it's committing hara-kiri...). Leave
|
|
* the socket open until pqReadData finds no more data
|
|
* can be read. But abandon attempt to send data.
|
|
*/
|
|
conn->outCount = 0;
|
|
return -1;
|
|
|
|
default:
|
|
printfPQExpBuffer(&conn->errorMessage,
|
|
libpq_gettext("could not send data to server: %s\n"),
|
|
SOCK_STRERROR(SOCK_ERRNO));
|
|
/* We don't assume it's a fatal error... */
|
|
conn->outCount = 0;
|
|
return -1;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
ptr += sent;
|
|
len -= sent;
|
|
remaining -= sent;
|
|
}
|
|
|
|
if (len > 0)
|
|
{
|
|
/* We didn't send it all, wait till we can send more */
|
|
|
|
/*
|
|
* if the socket is in non-blocking mode we may need to abort
|
|
* here and return 1 to indicate that data is still pending.
|
|
*/
|
|
#ifdef USE_SSL
|
|
/* can't do anything for our SSL users yet */
|
|
if (conn->ssl == NULL)
|
|
{
|
|
#endif
|
|
if (pqIsnonblocking(conn))
|
|
{
|
|
result = 1;
|
|
break;
|
|
}
|
|
#ifdef USE_SSL
|
|
}
|
|
#endif
|
|
|
|
if (pqWait(FALSE, TRUE, conn))
|
|
{
|
|
result = -1;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* shift the remaining contents of the buffer */
|
|
if (remaining > 0)
|
|
memmove(conn->outBuffer, ptr, remaining);
|
|
conn->outCount = remaining;
|
|
|
|
return result;
|
|
}
|
|
|
|
|
|
/*
|
|
* pqFlush: send any data waiting in the output buffer
|
|
*
|
|
* Return 0 on success, -1 on failure and 1 when not all data could be sent
|
|
* because the socket would block and the connection is non-blocking.
|
|
*/
|
|
int
|
|
pqFlush(PGconn *conn)
|
|
{
|
|
if (conn->Pfdebug)
|
|
fflush(conn->Pfdebug);
|
|
|
|
if (conn->outCount > 0)
|
|
return pqSendSome(conn, conn->outCount);
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
/*
|
|
* pqWait: wait until we can read or write the connection socket
|
|
*
|
|
* JAB: If SSL enabled and used and forRead, buffered bytes short-circuit the
|
|
* call to select().
|
|
*
|
|
* We also stop waiting and return if the kernel flags an exception condition
|
|
* on the socket. The actual error condition will be detected and reported
|
|
* when the caller tries to read or write the socket.
|
|
*/
|
|
int
|
|
pqWait(int forRead, int forWrite, PGconn *conn)
|
|
{
|
|
return pqWaitTimed(forRead, forWrite, conn, (time_t) -1);
|
|
}
|
|
|
|
/*
|
|
* pqWaitTimed: wait, but not past finish_time.
|
|
*
|
|
* If finish_time is exceeded then we return failure (EOF). This is like
|
|
* the response for a kernel exception because we don't want the caller
|
|
* to try to read/write in that case.
|
|
*
|
|
* finish_time = ((time_t) -1) disables the wait limit.
|
|
*/
|
|
int
|
|
pqWaitTimed(int forRead, int forWrite, PGconn *conn, time_t finish_time)
|
|
{
|
|
int result;
|
|
|
|
result = pqSocketCheck(conn, forRead, forWrite, finish_time);
|
|
|
|
if (result < 0)
|
|
return EOF; /* errorMessage is already set */
|
|
|
|
if (result == 0)
|
|
{
|
|
printfPQExpBuffer(&conn->errorMessage,
|
|
libpq_gettext("timeout expired\n"));
|
|
return EOF;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* pqReadReady: is select() saying the file is ready to read?
|
|
* Returns -1 on failure, 0 if not ready, 1 if ready.
|
|
*/
|
|
int
|
|
pqReadReady(PGconn *conn)
|
|
{
|
|
return pqSocketCheck(conn, 1, 0, (time_t) 0);
|
|
}
|
|
|
|
/*
|
|
* pqWriteReady: is select() saying the file is ready to write?
|
|
* Returns -1 on failure, 0 if not ready, 1 if ready.
|
|
*/
|
|
int
|
|
pqWriteReady(PGconn *conn)
|
|
{
|
|
return pqSocketCheck(conn, 0, 1, (time_t) 0);
|
|
}
|
|
|
|
/*
|
|
* Checks a socket, using poll or select, for data to be read, written,
|
|
* or both. Returns >0 if one or more conditions are met, 0 if it timed
|
|
* out, -1 if an error occurred.
|
|
*
|
|
* If SSL is in use, the SSL buffer is checked prior to checking the socket
|
|
* for read data directly.
|
|
*/
|
|
static int
|
|
pqSocketCheck(PGconn *conn, int forRead, int forWrite, time_t end_time)
|
|
{
|
|
int result;
|
|
|
|
if (!conn)
|
|
return -1;
|
|
if (conn->sock < 0)
|
|
{
|
|
printfPQExpBuffer(&conn->errorMessage,
|
|
libpq_gettext("socket not open\n"));
|
|
return -1;
|
|
}
|
|
|
|
#ifdef USE_SSL
|
|
/* Check for SSL library buffering read bytes */
|
|
if (forRead && conn->ssl && SSL_pending(conn->ssl) > 0)
|
|
{
|
|
/* short-circuit the select */
|
|
return 1;
|
|
}
|
|
#endif
|
|
|
|
/* We will retry as long as we get EINTR */
|
|
do
|
|
{
|
|
result = pqSocketPoll(conn->sock, forRead, forWrite, end_time);
|
|
}
|
|
while (result < 0 && SOCK_ERRNO == EINTR);
|
|
|
|
if (result < 0)
|
|
{
|
|
printfPQExpBuffer(&conn->errorMessage,
|
|
libpq_gettext("select() failed: %s\n"),
|
|
SOCK_STRERROR(SOCK_ERRNO));
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
|
|
/*
|
|
* Check a file descriptor for read and/or write data, possibly waiting.
|
|
* If neither forRead nor forWrite are set, immediately return a timeout
|
|
* condition (without waiting). Return >0 if condition is met, 0
|
|
* if a timeout occurred, -1 if an error or interrupt occurred.
|
|
*
|
|
* Timeout is infinite if end_time is -1. Timeout is immediate (no blocking)
|
|
* if end_time is 0 (or indeed, any time before now).
|
|
*/
|
|
static int
|
|
pqSocketPoll(int sock, int forRead, int forWrite, time_t end_time)
|
|
{
|
|
/* We use poll(2) if available, otherwise select(2) */
|
|
#ifdef HAVE_POLL
|
|
struct pollfd input_fd;
|
|
int timeout_ms;
|
|
|
|
if (!forRead && !forWrite)
|
|
return 0;
|
|
|
|
input_fd.fd = sock;
|
|
input_fd.events = POLLERR;
|
|
input_fd.revents = 0;
|
|
|
|
if (forRead)
|
|
input_fd.events |= POLLIN;
|
|
if (forWrite)
|
|
input_fd.events |= POLLOUT;
|
|
|
|
/* Compute appropriate timeout interval */
|
|
if (end_time == ((time_t) -1))
|
|
{
|
|
timeout_ms = -1;
|
|
}
|
|
else
|
|
{
|
|
time_t now = time(NULL);
|
|
|
|
if (end_time > now)
|
|
timeout_ms = (end_time - now) * 1000;
|
|
else
|
|
timeout_ms = 0;
|
|
}
|
|
|
|
return poll(&input_fd, 1, timeout_ms);
|
|
|
|
#else /* !HAVE_POLL */
|
|
|
|
fd_set input_mask;
|
|
fd_set output_mask;
|
|
fd_set except_mask;
|
|
struct timeval timeout;
|
|
struct timeval *ptr_timeout;
|
|
|
|
if (!forRead && !forWrite)
|
|
return 0;
|
|
|
|
FD_ZERO(&input_mask);
|
|
FD_ZERO(&output_mask);
|
|
FD_ZERO(&except_mask);
|
|
if (forRead)
|
|
FD_SET(sock, &input_mask);
|
|
if (forWrite)
|
|
FD_SET(sock, &output_mask);
|
|
FD_SET(sock, &except_mask);
|
|
|
|
/* Compute appropriate timeout interval */
|
|
if (end_time == ((time_t) -1))
|
|
{
|
|
ptr_timeout = NULL;
|
|
}
|
|
else
|
|
{
|
|
time_t now = time(NULL);
|
|
|
|
if (end_time > now)
|
|
timeout.tv_sec = end_time - now;
|
|
else
|
|
timeout.tv_sec = 0;
|
|
timeout.tv_usec = 0;
|
|
ptr_timeout = &timeout;
|
|
}
|
|
|
|
return select(sock + 1, &input_mask, &output_mask,
|
|
&except_mask, ptr_timeout);
|
|
#endif /* HAVE_POLL */
|
|
}
|
|
|
|
|
|
/*
|
|
* A couple of "miscellaneous" multibyte related functions. They used
|
|
* to be in fe-print.c but that file is doomed.
|
|
*/
|
|
|
|
/*
|
|
* returns the byte length of the word beginning s, using the
|
|
* specified encoding.
|
|
*/
|
|
int
|
|
PQmblen(const unsigned char *s, int encoding)
|
|
{
|
|
return (pg_encoding_mblen(encoding, s));
|
|
}
|
|
|
|
/*
|
|
* Get encoding id from environment variable PGCLIENTENCODING.
|
|
*/
|
|
int
|
|
PQenv2encoding(void)
|
|
{
|
|
char *str;
|
|
int encoding = PG_SQL_ASCII;
|
|
|
|
str = getenv("PGCLIENTENCODING");
|
|
if (str && *str != '\0')
|
|
encoding = pg_char_to_encoding(str);
|
|
return (encoding);
|
|
}
|
|
|
|
|
|
#ifdef ENABLE_NLS
|
|
|
|
char *
|
|
libpq_gettext(const char *msgid)
|
|
{
|
|
static int already_bound = 0;
|
|
|
|
if (!already_bound)
|
|
{
|
|
already_bound = 1;
|
|
bindtextdomain("libpq", LOCALEDIR);
|
|
}
|
|
|
|
return dgettext("libpq", msgid);
|
|
}
|
|
|
|
#endif /* ENABLE_NLS */
|