fe-misc.c File Reference

#include "postgres_fe.h"
#include <signal.h>
#include <time.h>
#include <unistd.h>
#include "libpq-fe.h"
#include "libpq-int.h"
#include "mb/pg_wchar.h"
#include "pg_config_paths.h"
#include "port/pg_bswap.h"

Include dependency graph for fe-misc.c:

Go to the source code of this file.

Functions
static int	pqPutMsgBytes (const void *buf, size_t len, PGconn *conn)
static int	pqSendSome (PGconn *conn, int len)
static int	pqSocketCheck (PGconn *conn, int forRead, int forWrite, time_t end_time)
static int	pqSocketPoll (int sock, int forRead, int forWrite, time_t end_time)
int	PQlibVersion (void)
int	pqGetc (char *result, PGconn *conn)
int	pqPutc (char c, PGconn *conn)
static int	pqGets_internal (PQExpBuffer buf, PGconn *conn, bool resetbuffer)
int	pqGets (PQExpBuffer buf, PGconn *conn)
int	pqGets_append (PQExpBuffer buf, PGconn *conn)
int	pqPuts (const char *s, PGconn *conn)
int	pqGetnchar (char *s, size_t len, PGconn *conn)
int	pqSkipnchar (size_t len, PGconn *conn)
int	pqPutnchar (const char *s, size_t len, PGconn *conn)
int	pqGetInt (int *result, size_t bytes, PGconn *conn)
int	pqPutInt (int value, size_t bytes, PGconn *conn)
int	pqCheckOutBufferSpace (size_t bytes_needed, PGconn *conn)
int	pqCheckInBufferSpace (size_t bytes_needed, PGconn *conn)
int	pqPutMsgStart (char msg_type, PGconn *conn)
int	pqPutMsgEnd (PGconn *conn)
int	pqReadData (PGconn *conn)
int	pqFlush (PGconn *conn)
int	pqWait (int forRead, int forWrite, PGconn *conn)
int	pqWaitTimed (int forRead, int forWrite, PGconn *conn, time_t finish_time)
int	pqReadReady (PGconn *conn)
int	pqWriteReady (PGconn *conn)
int	PQmblen (const char *s, int encoding)
int	PQmblenBounded (const char *s, int encoding)
int	PQdsplen (const char *s, int encoding)
int	PQenv2encoding (void)

Function Documentation

pqCheckInBufferSpace()

int pqCheckInBufferSpace	(	size_t	bytes_needed,
		PGconn *	conn
	)

Definition at line 354 of file fe-misc.c.

References appendPQExpBufferStr(), pg_conn::errorMessage, pg_conn::inBuffer, pg_conn::inBufSize, pg_conn::inCursor, pg_conn::inEnd, pg_conn::inStart, and realloc.

Referenced by getCopyDataMessage(), PQconnectPoll(), pqFunctionCall3(), pqParseInput3(), and pqReadData().

{
    int         newsize = conn->inBufSize;
    char       *newbuf;

    /* Quick exit if we have enough space */
    if (bytes_needed <= (size_t) newsize)
        return 0;

    /*
     * Before concluding that we need to enlarge the buffer, left-justify
     * whatever is in it and recheck.  The caller's value of bytes_needed
     * includes any data to the left of inStart, but we can delete that in
     * preference to enlarging the buffer.  It's slightly ugly to have this
     * function do this, but it's better than making callers worry about it.
     */
    bytes_needed -= conn->inStart;

    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;
    }

    /* Recheck whether we have enough space */
    if (bytes_needed <= (size_t) newsize)
        return 0;

    /*
     * If we need to enlarge the buffer, we first try to double it in size; if
     * that doesn't work, enlarge in multiples of 8K.  This avoids thrashing
     * the malloc pool by repeated small enlargements.
     *
     * Note: tests for newsize > 0 are to catch integer overflow.
     */
    do
    {
        newsize *= 2;
    } while (newsize > 0 && bytes_needed > (size_t) newsize);

    if (newsize > 0 && bytes_needed <= (size_t) newsize)
    {
        newbuf = realloc(conn->inBuffer, newsize);
        if (newbuf)
        {
            /* realloc succeeded */
            conn->inBuffer = newbuf;
            conn->inBufSize = newsize;
            return 0;
        }
    }

    newsize = conn->inBufSize;
    do
    {
        newsize += 8192;
    } while (newsize > 0 && bytes_needed > (size_t) newsize);

    if (newsize > 0 && bytes_needed <= (size_t) newsize)
    {
        newbuf = realloc(conn->inBuffer, newsize);
        if (newbuf)
        {
            /* realloc succeeded */
            conn->inBuffer = newbuf;
            conn->inBufSize = newsize;
            return 0;
        }
    }

    /* realloc failed. Probably out of memory */
    appendPQExpBufferStr(&conn->errorMessage,
                         "cannot allocate memory for input buffer\n");
    return EOF;
}

pqCheckOutBufferSpace()

int pqCheckOutBufferSpace	(	size_t	bytes_needed,
		PGconn *	conn
	)

Definition at line 290 of file fe-misc.c.

References appendPQExpBufferStr(), pg_conn::errorMessage, pg_conn::outBuffer, pg_conn::outBufSize, and realloc.

Referenced by PQputCopyData(), pqPutMsgBytes(), and pqPutMsgStart().

{
    int         newsize = conn->outBufSize;
    char       *newbuf;

    /* Quick exit if we have enough space */
    if (bytes_needed <= (size_t) newsize)
        return 0;

    /*
     * If we need to enlarge the buffer, we first try to double it in size; if
     * that doesn't work, enlarge in multiples of 8K.  This avoids thrashing
     * the malloc pool by repeated small enlargements.
     *
     * Note: tests for newsize > 0 are to catch integer overflow.
     */
    do
    {
        newsize *= 2;
    } while (newsize > 0 && bytes_needed > (size_t) newsize);

    if (newsize > 0 && bytes_needed <= (size_t) newsize)
    {
        newbuf = realloc(conn->outBuffer, newsize);
        if (newbuf)
        {
            /* realloc succeeded */
            conn->outBuffer = newbuf;
            conn->outBufSize = newsize;
            return 0;
        }
    }

    newsize = conn->outBufSize;
    do
    {
        newsize += 8192;
    } while (newsize > 0 && bytes_needed > (size_t) newsize);

    if (newsize > 0 && bytes_needed <= (size_t) newsize)
    {
        newbuf = realloc(conn->outBuffer, newsize);
        if (newbuf)
        {
            /* realloc succeeded */
            conn->outBuffer = newbuf;
            conn->outBufSize = newsize;
            return 0;
        }
    }

    /* realloc failed. Probably out of memory */
    appendPQExpBufferStr(&conn->errorMessage,
                         "cannot allocate memory for output buffer\n");
    return EOF;
}

PQdsplen()

int PQdsplen	(	const char *	s,
		int	encoding
	)

Definition at line 1212 of file fe-misc.c.

References pg_encoding_dsplen().

Referenced by get_prompt(), pg_wcsformat(), pg_wcssize(), pg_wcswidth(), and strlen_max_width().

{
    return pg_encoding_dsplen(encoding, s);
}

PQenv2encoding()

int PQenv2encoding

(

void

)

Definition at line 1221 of file fe-misc.c.

References dgettext, dngettext, encoding, libpq_gettext, libpq_ngettext, pg_char_to_encoding(), PG_SQL_ASCII, PG_TEXTDOMAIN, and generate_unaccent_rules::str.

Referenced by main().

{
    char       *str;
    int         encoding = PG_SQL_ASCII;

    str = getenv("PGCLIENTENCODING");
    if (str && *str != '\0')
    {
        encoding = pg_char_to_encoding(str);
        if (encoding < 0)
            encoding = PG_SQL_ASCII;
    }
    return encoding;
}

pqFlush()

int pqFlush

(

PGconn *

conn

)

Definition at line 965 of file fe-misc.c.

References pg_conn::outCount, pg_conn::Pfdebug, and pqSendSome().

Referenced by pg_SASL_init(), PQconnectPoll(), PQconsumeInput(), pqEndcopy3(), PQexitPipelineMode(), PQflush(), pqFunctionCall3(), PQgetResult(), pqPacketSend(), pqPipelineFlush(), PQputCopyData(), PQputCopyEnd(), PQsetnonblocking(), and sendTerminateConn().

{
    if (conn->outCount > 0)
    {
        if (conn->Pfdebug)
            fflush(conn->Pfdebug);

        return pqSendSome(conn, conn->outCount);
    }

    return 0;
}

pqGetc()

int pqGetc	(	char *	result,
		PGconn *	conn
	)

Definition at line 80 of file fe-misc.c.

References pg_conn::inBuffer, pg_conn::inCursor, and pg_conn::inEnd.

Referenced by getCopyDataMessage(), getCopyStart(), getReadyForQuery(), PQconnectPoll(), pqFunctionCall3(), pqGetErrorNotice3(), and pqParseInput3().

{
    if (conn->inCursor >= conn->inEnd)
        return EOF;

    *result = conn->inBuffer[conn->inCursor++];

    return 0;
}

pqGetInt()

int pqGetInt	(	int *	result,
		size_t	bytes,
		PGconn *	conn
	)

Definition at line 219 of file fe-misc.c.

References pg_conn::inBuffer, pg_conn::inCursor, pg_conn::inEnd, pg_conn::noticeHooks, pg_ntoh16, pg_ntoh32, and pqInternalNotice().

Referenced by getAnotherTuple(), getCopyDataMessage(), getCopyStart(), getNotify(), getParamDescriptions(), getRowDescriptions(), PQconnectPoll(), pqFunctionCall3(), and pqParseInput3().

{
    uint16      tmp2;
    uint32      tmp4;

    switch (bytes)
    {
        case 2:
            if (conn->inCursor + 2 > conn->inEnd)
                return EOF;
            memcpy(&tmp2, conn->inBuffer + conn->inCursor, 2);
            conn->inCursor += 2;
            *result = (int) pg_ntoh16(tmp2);
            break;
        case 4:
            if (conn->inCursor + 4 > conn->inEnd)
                return EOF;
            memcpy(&tmp4, conn->inBuffer + conn->inCursor, 4);
            conn->inCursor += 4;
            *result = (int) pg_ntoh32(tmp4);
            break;
        default:
            pqInternalNotice(&conn->noticeHooks,
                             "integer of size %lu not supported by pqGetInt",
                             (unsigned long) bytes);
            return EOF;
    }

    return 0;
}

pqGetnchar()

int pqGetnchar	(	char *	s,
		size_t	len,
		PGconn *	conn
	)

Definition at line 168 of file fe-misc.c.

References pg_conn::inBuffer, pg_conn::inCursor, and pg_conn::inEnd.

Referenced by pg_password_sendauth(), pg_SASL_continue(), and pqFunctionCall3().

{
    if (len > (size_t) (conn->inEnd - conn->inCursor))
        return EOF;

    memcpy(s, conn->inBuffer + conn->inCursor, len);
    /* no terminating null */

    conn->inCursor += len;

    return 0;
}

pqGets()

int pqGets	(	PQExpBuffer	buf,
		PGconn *	conn
	)

Definition at line 139 of file fe-misc.c.

References pqGets_internal().

Referenced by getNotify(), getParameterStatus(), getRowDescriptions(), pg_SASL_init(), pqGetErrorNotice3(), and pqParseInput3().

{
    return pqGets_internal(buf, conn, true);
}

pqGets_append()

int pqGets_append	(	PQExpBuffer	buf,
		PGconn *	conn
	)

Definition at line 145 of file fe-misc.c.

References pqGets_internal().

Referenced by PQconnectPoll().

{
    return pqGets_internal(buf, conn, false);
}

pqGets_internal()

static int pqGets_internal ( PQExpBuffer  buf, PGconn *  conn, bool  resetbuffer  )

static

Definition at line 112 of file fe-misc.c.

References appendBinaryPQExpBuffer(), pg_conn::inBuffer, pg_conn::inCursor, pg_conn::inEnd, and resetPQExpBuffer().

Referenced by pqGets(), and pqGets_append().

{
    /* Copy conn data to locals for faster search loop */
    char       *inBuffer = conn->inBuffer;
    int         inCursor = conn->inCursor;
    int         inEnd = conn->inEnd;
    int         slen;

    while (inCursor < inEnd && inBuffer[inCursor])
        inCursor++;

    if (inCursor >= inEnd)
        return EOF;

    slen = inCursor - conn->inCursor;

    if (resetbuffer)
        resetPQExpBuffer(buf);

    appendBinaryPQExpBuffer(buf, inBuffer + conn->inCursor, slen);

    conn->inCursor = ++inCursor;

    return 0;
}

PQlibVersion()

int PQlibVersion

(

void

)

Definition at line 66 of file fe-misc.c.

{
    return PG_VERSION_NUM;
}

PQmblen()

int PQmblen	(	const char *	s,
		int	encoding
	)

Definition at line 1192 of file fe-misc.c.

References pg_encoding_mblen().

Referenced by appendStringLiteral(), get_prompt(), pg_wcsformat(), pg_wcssize(), pg_wcswidth(), and strlen_max_width().

{
    return pg_encoding_mblen(encoding, s);
}

PQmblenBounded()

int PQmblenBounded	(	const char *	s,
		int	encoding
	)

Definition at line 1202 of file fe-misc.c.

References pg_encoding_mblen(), and strnlen().

Referenced by command_no_begin(), do_field(), is_select_command(), patternToSQLRegex(), quote_if_needed(), reportErrorPosition(), skip_white_space(), splitTableColumnsSpec(), strip_quotes(), and strtokx().

{
    return strnlen(s, pg_encoding_mblen(encoding, s));
}

pqPutc()

int pqPutc	(	char	c,
		PGconn *	conn
	)

Definition at line 95 of file fe-misc.c.

References pqPutMsgBytes().

Referenced by PQsendDescribe(), PQsendQueryGuts(), and PQsendQueryInternal().

{
    if (pqPutMsgBytes(&c, 1, conn))
        return EOF;

    return 0;
}

pqPutInt()

int pqPutInt	(	int	value,
		size_t	bytes,
		PGconn *	conn
	)

Definition at line 256 of file fe-misc.c.

References pg_conn::noticeHooks, pg_hton16, pg_hton32, pqInternalNotice(), and pqPutMsgBytes().

Referenced by pg_SASL_init(), pqFunctionCall3(), PQsendPrepare(), PQsendQueryGuts(), and PQsendQueryInternal().

{
    uint16      tmp2;
    uint32      tmp4;

    switch (bytes)
    {
        case 2:
            tmp2 = pg_hton16((uint16) value);
            if (pqPutMsgBytes((const char *) &tmp2, 2, conn))
                return EOF;
            break;
        case 4:
            tmp4 = pg_hton32((uint32) value);
            if (pqPutMsgBytes((const char *) &tmp4, 4, conn))
                return EOF;
            break;
        default:
            pqInternalNotice(&conn->noticeHooks,
                             "integer of size %lu not supported by pqPutInt",
                             (unsigned long) bytes);
            return EOF;
    }

    return 0;
}

pqPutMsgBytes()

static int pqPutMsgBytes ( const void *  buf, size_t  len, PGconn *  conn  )

static

Definition at line 497 of file fe-misc.c.

References pg_conn::outBuffer, pg_conn::outMsgEnd, and pqCheckOutBufferSpace().

Referenced by pqPutc(), pqPutInt(), pqPutnchar(), and pqPuts().

{
    /* 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()

int pqPutMsgEnd

(

PGconn *

conn

)

Definition at line 520 of file fe-misc.c.

References pg_conn::outBuffer, pg_conn::outCount, pg_conn::outMsgEnd, pg_conn::outMsgStart, pg_conn::Pfdebug, pg_hton32, pqSendSome(), pqTraceOutputMessage(), and pqTraceOutputNoTypeByteMessage().

Referenced by pg_SASL_init(), pqEndcopy3(), pqFunctionCall3(), pqPacketSend(), PQpipelineSync(), PQputCopyData(), PQputCopyEnd(), PQsendDescribe(), PQsendFlushRequest(), PQsendPrepare(), PQsendQueryGuts(), PQsendQueryInternal(), and sendTerminateConn().

{
    /* Fill in length word if needed */
    if (conn->outMsgStart >= 0)
    {
        uint32      msgLen = conn->outMsgEnd - conn->outMsgStart;

        msgLen = pg_hton32(msgLen);
        memcpy(conn->outBuffer + conn->outMsgStart, &msgLen, 4);
    }

    /* trace client-to-server message */
    if (conn->Pfdebug)
    {
        if (conn->outCount < conn->outMsgStart)
            pqTraceOutputMessage(conn, conn->outBuffer + conn->outCount, true);
        else
            pqTraceOutputNoTypeByteMessage(conn,
                                           conn->outBuffer + conn->outMsgStart);
    }

    /* 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;
}

pqPutMsgStart()

int pqPutMsgStart	(	char	msg_type,
		PGconn *	conn
	)

Definition at line 461 of file fe-misc.c.

References pg_conn::outBuffer, pg_conn::outCount, pg_conn::outMsgEnd, pg_conn::outMsgStart, and pqCheckOutBufferSpace().

Referenced by pg_SASL_init(), pqEndcopy3(), pqFunctionCall3(), pqPacketSend(), PQpipelineSync(), PQputCopyData(), PQputCopyEnd(), PQsendDescribe(), PQsendFlushRequest(), PQsendPrepare(), PQsendQueryGuts(), PQsendQueryInternal(), and sendTerminateConn().

{
    int         lenPos;
    int         endPos;

    /* allow room for message type byte */
    if (msg_type)
        endPos = conn->outCount + 1;
    else
        endPos = conn->outCount;

    /* do we want a length word? */
    lenPos = endPos;
    /* allow room for message length */
    endPos += 4;

    /* make sure there is room for message header */
    if (pqCheckOutBufferSpace(endPos, conn))
        return EOF;
    /* okay, save the message type byte if any */
    if (msg_type)
        conn->outBuffer[conn->outCount] = msg_type;
    /* set up the message pointers */
    conn->outMsgStart = lenPos;
    conn->outMsgEnd = endPos;
    /* length word, if needed, will be filled in by pqPutMsgEnd */

    return 0;
}

pqPutnchar()

int pqPutnchar	(	const char *	s,
		size_t	len,
		PGconn *	conn
	)

Definition at line 205 of file fe-misc.c.

References pqPutMsgBytes().

Referenced by pg_SASL_init(), pqFunctionCall3(), pqPacketSend(), PQputCopyData(), and PQsendQueryGuts().

{
    if (pqPutMsgBytes(s, len, conn))
        return EOF;

    return 0;
}

pqPuts()

int pqPuts	(	const char *	s,
		PGconn *	conn
	)

Definition at line 155 of file fe-misc.c.

References pqPutMsgBytes().

Referenced by pg_SASL_init(), PQputCopyEnd(), PQsendDescribe(), PQsendPrepare(), PQsendQueryGuts(), and PQsendQueryInternal().

{
    if (pqPutMsgBytes(s, strlen(s) + 1, conn))
        return EOF;

    return 0;
}

pqReadData()

int pqReadData

(

PGconn *

conn

)

Definition at line 568 of file fe-misc.c.

References ALL_CONNECTION_FAILURE_ERRNOS, appendPQExpBufferStr(), CONNECTION_BAD, EAGAIN, EINTR, pg_conn::errorMessage, EWOULDBLOCK, pg_conn::inBuffer, pg_conn::inBufSize, pg_conn::inCursor, pg_conn::inEnd, pg_conn::inStart, libpq_gettext, PGINVALID_SOCKET, pqCheckInBufferSpace(), pqDropConnection(), pqReadReady(), pqsecure_read(), pg_conn::sock, SOCK_ERRNO, pg_conn::ssl_in_use, and pg_conn::status.

Referenced by PQconnectPoll(), PQconsumeInput(), pqFunctionCall3(), pqGetCopyData3(), pqGetline3(), PQgetResult(), and pqSendSome().

{
    int         someread = 0;
    int         nread;

    if (conn->sock == PGINVALID_SOCKET)
    {
        appendPQExpBufferStr(&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 + (size_t) 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)
    {
        switch (SOCK_ERRNO)
        {
            case EINTR:
                goto retry3;

                /* Some systems return EAGAIN/EWOULDBLOCK for no data */
#ifdef EAGAIN
            case EAGAIN:
                return someread;
#endif
#if defined(EWOULDBLOCK) && (!defined(EAGAIN) || (EWOULDBLOCK != EAGAIN))
            case EWOULDBLOCK:
                return someread;
#endif

                /* We might get ECONNRESET etc here if connection failed */
            case ALL_CONNECTION_FAILURE_ERRNOS:
                goto definitelyFailed;

            default:
                /* pqsecure_read set the error message for us */
                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.
     *
     * In SSL mode it's even worse: SSL_read() could say WANT_READ and then
     * data could arrive before we make the pqReadReady() test, but the second
     * SSL_read() could still say WANT_READ because the data received was not
     * a complete SSL record.  So we must play dumb and assume there is more
     * data, relying on the SSL layer to detect true EOF.
     */

#ifdef USE_SSL
    if (conn->ssl_in_use)
        return 0;
#endif

    switch (pqReadReady(conn))
    {
        case 0:
            /* definitely no data available */
            return 0;
        case 1:
            /* ready for read */
            break;
        default:
            /* we override pqReadReady's message with something more useful */
            goto definitelyEOF;
    }

    /*
     * 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)
    {
        switch (SOCK_ERRNO)
        {
            case EINTR:
                goto retry4;

                /* Some systems return EAGAIN/EWOULDBLOCK for no data */
#ifdef EAGAIN
            case EAGAIN:
                return 0;
#endif
#if defined(EWOULDBLOCK) && (!defined(EAGAIN) || (EWOULDBLOCK != EAGAIN))
            case EWOULDBLOCK:
                return 0;
#endif

                /* We might get ECONNRESET etc here if connection failed */
            case ALL_CONNECTION_FAILURE_ERRNOS:
                goto definitelyFailed;

            default:
                /* pqsecure_read set the error message for us */
                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.
     */
definitelyEOF:
    appendPQExpBufferStr(&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"));

    /* Come here if lower-level code already set a suitable errorMessage */
definitelyFailed:
    /* Do *not* drop any already-read data; caller still wants it */
    pqDropConnection(conn, false);
    conn->status = CONNECTION_BAD;  /* No more connection to backend */
    return -1;
}

pqReadReady()

int pqReadReady

(

PGconn *

conn

)

Definition at line 1027 of file fe-misc.c.

References pqSocketCheck().

Referenced by gss_read(), and pqReadData().

{
    return pqSocketCheck(conn, 1, 0, (time_t) 0);
}

pqSendSome()

static int pqSendSome ( PGconn *  conn, int  len  )

static

Definition at line 788 of file fe-misc.c.

References PQExpBufferData::data, EAGAIN, EINTR, pg_conn::errorMessage, EWOULDBLOCK, PQExpBufferData::len, libpq_gettext, Min, pg_conn::outBuffer, pg_conn::outCount, PGINVALID_SOCKET, PQExpBufferBroken, pqIsnonblocking, pqReadData(), pqsecure_write(), pqWait(), remaining, pg_conn::sock, SOCK_ERRNO, pg_conn::write_err_msg, and pg_conn::write_failed.

Referenced by pqFlush(), and pqPutMsgEnd().

{
    char       *ptr = conn->outBuffer;
    int         remaining = conn->outCount;
    int         oldmsglen = conn->errorMessage.len;
    int         result = 0;

    /*
     * If we already had a write failure, we will never again try to send data
     * on that connection.  Even if the kernel would let us, we've probably
     * lost message boundary sync with the server.  conn->write_failed
     * therefore persists until the connection is reset, and we just discard
     * all data presented to be written.  However, as long as we still have a
     * valid socket, we should continue to absorb data from the backend, so
     * that we can collect any final error messages.
     */
    if (conn->write_failed)
    {
        /* conn->write_err_msg should be set up already */
        conn->outCount = 0;
        /* Absorb input data if any, and detect socket closure */
        if (conn->sock != PGINVALID_SOCKET)
        {
            if (pqReadData(conn) < 0)
                return -1;
        }
        return 0;
    }

    if (conn->sock == PGINVALID_SOCKET)
    {
        conn->write_failed = true;
        /* Insert error message into conn->write_err_msg, if possible */
        /* (strdup failure is OK, we'll cope later) */
        conn->write_err_msg = strdup(libpq_gettext("connection not open\n"));
        /* Discard queued data; no chance it'll ever be sent */
        conn->outCount = 0;
        return 0;
    }

    /* while there's still data to send */
    while (len > 0)
    {
        int         sent;

#ifndef WIN32
        sent = pqsecure_write(conn, ptr, len);
#else

        /*
         * Windows can fail on large sends, per KB article Q201213. The
         * failure-point appears to be different in different versions of
         * Windows, but 64k should always be safe.
         */
        sent = pqsecure_write(conn, ptr, Min(len, 65536));
#endif

        if (sent < 0)
        {
            /* Anything except EAGAIN/EWOULDBLOCK/EINTR is trouble */
            switch (SOCK_ERRNO)
            {
#ifdef EAGAIN
                case EAGAIN:
                    break;
#endif
#if defined(EWOULDBLOCK) && (!defined(EAGAIN) || (EWOULDBLOCK != EAGAIN))
                case EWOULDBLOCK:
                    break;
#endif
                case EINTR:
                    continue;

                default:
                    /* pqsecure_write set the error message for us */
                    conn->write_failed = true;

                    /*
                     * Transfer error message to conn->write_err_msg, if
                     * possible (strdup failure is OK, we'll cope later).
                     *
                     * We only want to transfer whatever has been appended to
                     * conn->errorMessage since we entered this routine.
                     */
                    if (!PQExpBufferBroken(&conn->errorMessage))
                    {
                        conn->write_err_msg = strdup(conn->errorMessage.data +
                                                     oldmsglen);
                        conn->errorMessage.len = oldmsglen;
                        conn->errorMessage.data[oldmsglen] = '\0';
                    }

                    /* Discard queued data; no chance it'll ever be sent */
                    conn->outCount = 0;

                    /* Absorb input data if any, and detect socket closure */
                    if (conn->sock != PGINVALID_SOCKET)
                    {
                        if (pqReadData(conn) < 0)
                            return -1;
                    }
                    return 0;
            }
        }
        else
        {
            ptr += sent;
            len -= sent;
            remaining -= sent;
        }

        if (len > 0)
        {
            /*
             * We didn't send it all, wait till we can send more.
             *
             * There are scenarios in which we can't send data because the
             * communications channel is full, but we cannot expect the server
             * to clear the channel eventually because it's blocked trying to
             * send data to us.  (This can happen when we are sending a large
             * amount of COPY data, and the server has generated lots of
             * NOTICE responses.)  To avoid a deadlock situation, we must be
             * prepared to accept and buffer incoming data before we try
             * again.  Furthermore, it is possible that such incoming data
             * might not arrive until after we've gone to sleep.  Therefore,
             * we wait for either read ready or write ready.
             *
             * In non-blocking mode, we don't wait here directly, but return 1
             * to indicate that data is still pending.  The caller should wait
             * for both read and write ready conditions, and call
             * PQconsumeInput() on read ready, but just in case it doesn't, we
             * call pqReadData() ourselves before returning.  That's not
             * enough if the data has not arrived yet, but it's the best we
             * can do, and works pretty well in practice.  (The documentation
             * used to say that you only need to wait for write-ready, so
             * there are still plenty of applications like that out there.)
             *
             * Note that errors here don't result in write_failed becoming
             * set.
             */
            if (pqReadData(conn) < 0)
            {
                result = -1;    /* error message already set up */
                break;
            }

            if (pqIsnonblocking(conn))
            {
                result = 1;
                break;
            }

            if (pqWait(true, 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;
}

pqSkipnchar()

int pqSkipnchar	(	size_t	len,
		PGconn *	conn
	)

Definition at line 190 of file fe-misc.c.

References pg_conn::inCursor, and pg_conn::inEnd.

Referenced by getAnotherTuple().

{
    if (len > (size_t) (conn->inEnd - conn->inCursor))
        return EOF;

    conn->inCursor += len;

    return 0;
}

pqSocketCheck()

static int pqSocketCheck ( PGconn *  conn, int  forRead, int  forWrite, time_t  end_time  )

static

Definition at line 1051 of file fe-misc.c.

References appendPQExpBuffer(), appendPQExpBufferStr(), EINTR, pg_conn::errorMessage, libpq_gettext, PG_STRERROR_R_BUFLEN, PGINVALID_SOCKET, pgtls_read_pending(), pqSocketPoll(), pg_conn::sock, SOCK_ERRNO, SOCK_STRERROR, and pg_conn::ssl_in_use.

Referenced by pqReadReady(), pqWaitTimed(), and pqWriteReady().

{
    int         result;

    if (!conn)
        return -1;
    if (conn->sock == PGINVALID_SOCKET)
    {
        appendPQExpBufferStr(&conn->errorMessage,
                             libpq_gettext("invalid socket\n"));
        return -1;
    }

#ifdef USE_SSL
    /* Check for SSL library buffering read bytes */
    if (forRead && conn->ssl_in_use && pgtls_read_pending(conn))
    {
        /* 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)
    {
        char        sebuf[PG_STRERROR_R_BUFLEN];

        appendPQExpBuffer(&conn->errorMessage,
                          libpq_gettext("%s() failed: %s\n"),
                          "select",
                          SOCK_STRERROR(SOCK_ERRNO, sebuf, sizeof(sebuf)));
    }

    return result;
}

pqSocketPoll()

static int pqSocketPoll ( int  sock, int  forRead, int  forWrite, time_t  end_time  )

static

Definition at line 1102 of file fe-misc.c.

References now(), and select.

Referenced by pqSocketCheck().

{
    /* 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 */
}

pqWait()

int pqWait	(	int	forRead,
		int	forWrite,
		PGconn *	conn
	)

Definition at line 990 of file fe-misc.c.

References pqWaitTimed().

Referenced by pqFunctionCall3(), pqGetCopyData3(), pqGetline3(), PQgetResult(), and pqSendSome().

{
    return pqWaitTimed(forRead, forWrite, conn, (time_t) -1);
}

pqWaitTimed()

int pqWaitTimed	(	int	forRead,
		int	forWrite,
		PGconn *	conn,
		time_t	finish_time
	)

Definition at line 1003 of file fe-misc.c.

References appendPQExpBufferStr(), pg_conn::errorMessage, libpq_gettext, and pqSocketCheck().

Referenced by connectDBComplete(), and pqWait().

{
    int         result;

    result = pqSocketCheck(conn, forRead, forWrite, finish_time);

    if (result < 0)
        return -1;              /* errorMessage is already set */

    if (result == 0)
    {
        appendPQExpBufferStr(&conn->errorMessage,
                             libpq_gettext("timeout expired\n"));
        return 1;
    }

    return 0;
}

pqWriteReady()

int pqWriteReady

(

PGconn *

conn

)

Definition at line 1037 of file fe-misc.c.

References pqSocketCheck().

{
    return pqSocketCheck(conn, 0, 1, (time_t) 0);
}