greenplumn fe-misc 源码
greenplumn fe-misc 代码
文件路径：/src/interfaces/libpq/fe-misc.c
/*-------------------------------------------------------------------------
*
* FILE
* fe-misc.c
*
* DESCRIPTION
* miscellaneous useful functions
*
* The communication routines here are analogous to the ones in
* backend/libpq/pqcomm.c and backend/libpq/pqcomprim.c, but operate
* in the considerably different environment of the frontend libpq.
* In particular, we work with a bare nonblock-mode socket, rather than
* a stdio stream, so that we can avoid unwanted blocking of the application.
*
* XXX: MOVE DEBUG PRINTOUT TO HIGHER LEVEL. As is, block and restart
* will cause repeat printouts.
*
* We must speak the same transmitted data representations as the backend
* routines.
*
*
* Portions Copyright (c) 2012-Present VMware, Inc. or its affiliates.
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/interfaces/libpq/fe-misc.c
*
*-------------------------------------------------------------------------
*/
#ifndef FRONTEND
#include "postgres.h"
#else
#include "postgres_fe.h"
#endif
#include <signal.h>
#include <time.h>
#ifdef WIN32
#include "win32.h"
#else
#include <unistd.h>
#include <sys/time.h>
#endif
#ifdef HAVE_POLL_H
#include <poll.h>
#endif
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
#include "libpq-fe.h"
#include "libpq-int.h"
#include "mb/pg_wchar.h"
#include "port/pg_bswap.h"
#include "pg_config_paths.h"
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);
/*
* PQlibVersion: return the libpq version number
*/
int
PQlibVersion(void)
{
return PG_VERSION_NUM;
}
/*
* fputnbytes: print exactly N bytes to a file
*
* We avoid using %.*s here because it can misbehave if the data
* is not valid in what libc thinks is the prevailing encoding.
*/
static void
fputnbytes(FILE *f, const char *str, size_t n)
{
while (n-- > 0)
fputc(*str++, f);
}
/*
* pqGetc: get 1 character from the connection
*
* All these routines return 0 on success, EOF on error.
* Note that for the Get routines, EOF only means there is not enough
* data in the buffer, not that there is necessarily a hard error.
*/
int
pqGetc(char *result, PGconn *conn)
{
if (conn->inCursor >= conn->inEnd)
return EOF;
*result = conn->inBuffer[conn->inCursor++];
if (conn->Pfdebug)
fprintf(conn->Pfdebug, "From backend> %c\n", *result);
return 0;
}
/*
* pqPutc: write 1 char to the current message
*/
int
pqPutc(char c, PGconn *conn)
{
if (pqPutMsgBytes(&c, 1, conn))
return EOF;
if (conn->Pfdebug)
fprintf(conn->Pfdebug, "To backend> %c\n", c);
return 0;
}
/*
* pqGets[_append]:
* get a null-terminated string from the connection,
* and store it in an expansible PQExpBuffer.
* If we run out of memory, all of the string is still read,
* but the excess characters are silently discarded.
*/
static int
pqGets_internal(PQExpBuffer buf, PGconn *conn, bool resetbuffer)
{
/* 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;
if (conn->Pfdebug)
fprintf(conn->Pfdebug, "From backend> \"%s\"\n",
buf->data);
return 0;
}
int
pqGets(PQExpBuffer buf, PGconn *conn)
{
return pqGets_internal(buf, conn, true);
}
int
pqGets_append(PQExpBuffer buf, PGconn *conn)
{
return pqGets_internal(buf, conn, false);
}
/*
* pqPuts: write a null-terminated string to the current message
*/
int
pqPuts(const char *s, PGconn *conn)
{
if (pqPutMsgBytes(s, strlen(s) + 1, conn))
return EOF;
if (conn->Pfdebug)
fprintf(conn->Pfdebug, "To backend> \"%s\"\n", s);
return 0;
}
/*
* pqGetnchar:
* get a string of exactly len bytes in buffer s, no null termination
*/
int
pqGetnchar(char *s, size_t len, PGconn *conn)
{
if (len > (size_t) (conn->inEnd - conn->inCursor))
return EOF;
memcpy(s, conn->inBuffer + conn->inCursor, len);
/* no terminating null */
conn->inCursor += len;
if (conn->Pfdebug)
{
fprintf(conn->Pfdebug, "From backend (%lu)> ", (unsigned long) len);
fputnbytes(conn->Pfdebug, s, len);
fprintf(conn->Pfdebug, "\n");
}
return 0;
}
/*
* pqSkipnchar:
* skip over len bytes in input buffer.
*
* Note: this is primarily useful for its debug output, which should
* be exactly the same as for pqGetnchar. We assume the data in question
* will actually be used, but just isn't getting copied anywhere as yet.
*/
int
pqSkipnchar(size_t len, PGconn *conn)
{
if (len > (size_t) (conn->inEnd - conn->inCursor))
return EOF;
if (conn->Pfdebug)
{
fprintf(conn->Pfdebug, "From backend (%lu)> ", (unsigned long) len);
fputnbytes(conn->Pfdebug, conn->inBuffer + conn->inCursor, len);
fprintf(conn->Pfdebug, "\n");
}
conn->inCursor += len;
return 0;
}
/*
* pqPutnchar:
* write exactly len bytes to the current message
*/
int
pqPutnchar(const char *s, size_t len, PGconn *conn)
{
if (pqPutMsgBytes(s, len, conn))
return EOF;
if (conn->Pfdebug)
{
fprintf(conn->Pfdebug, "To backend> ");
fputnbytes(conn->Pfdebug, s, len);
fprintf(conn->Pfdebug, "\n");
}
return 0;
}
/*
* pqGetInt
* read a 2 or 4 byte integer and convert from network byte order
* to local byte order
*/
int
pqGetInt(int *result, size_t bytes, PGconn *conn)
{
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;
}
if (conn->Pfdebug)
fprintf(conn->Pfdebug, "From backend (#%lu)> %d\n", (unsigned long) bytes, *result);
return 0;
}
int64
pqGetInt64(int64 *result, PGconn *conn)
{
int64 tmp;
uint32 h32;
uint32 l32;
if (conn->inCursor + 8 > conn->inEnd)
return EOF;
memcpy(&h32, conn->inBuffer + conn->inCursor, 4);
conn->inCursor += 4;
memcpy(&l32, conn->inBuffer + conn->inCursor, 4);
conn->inCursor += 4;
h32 = ntohl(h32);
l32 = ntohl(l32);
#ifdef INT64_IS_BUSTED
/* error out if incoming value is wider than 32 bits */
tmp = l32;
if ((tmp < 0) ? (h32 != -1) : (h32 != 0))
{
pqInternalNotice(&conn->noticeHooks,
"binary value is out of range for type bigint");
return EOF;
}
#else
tmp = h32;
tmp <<= 32;
tmp |= l32;
#endif
*result = tmp;
return 0;
}
/*
* pqPutInt
* write an integer of 2 or 4 bytes, converting from host byte order
* to network byte order.
*/
int
pqPutInt(int value, size_t bytes, PGconn *conn)
{
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;
}
if (conn->Pfdebug)
fprintf(conn->Pfdebug, "To backend (%lu#)> %d\n", (unsigned long) bytes, value);
return 0;
}
/*
* Make sure conn's output buffer can hold bytes_needed bytes (caller must
* include already-stored data into the value!)
*
* Returns 0 on success, EOF if failed to enlarge buffer
*/
int
pqCheckOutBufferSpace(size_t bytes_needed, PGconn *conn)
{
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 */
printfPQExpBuffer(&conn->errorMessage,
"cannot allocate memory for output buffer\n");
return EOF;
}
/*
* Make sure conn's input buffer can hold bytes_needed bytes (caller must
* include already-stored data into the value!)
*
* Returns 0 on success, EOF if failed to enlarge buffer
*/
int
pqCheckInBufferSpace(size_t bytes_needed, PGconn *conn)
{
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 */
printfPQExpBuffer(&conn->errorMessage,
"cannot allocate memory for input buffer\n");
return EOF;
}
/*
* pqPutMsgStart: begin construction of a message to the server
*
* msg_type is the message type byte, or 0 for a message without type byte
* (only startup messages have no type byte)
*
* force_len forces the message to have a length word; otherwise, we add
* a length word if protocol 3.
*
* Returns 0 on success, EOF on error
*
* The idea here is that we construct the message in conn->outBuffer,
* beginning just past any data already in outBuffer (ie, at
* outBuffer+outCount). We enlarge the buffer as needed to hold the message.
* When the message is complete, we fill in the length word (if needed) and
* then advance outCount past the message, making it eligible to send.
*
* The state variable conn->outMsgStart points to the incomplete message's
* length word: it is either outCount or outCount+1 depending on whether
* there is a type byte. If we are sending a message without length word
* (pre protocol 3.0 only), then outMsgStart is -1. The state variable
* conn->outMsgEnd is the end of the data collected so far.
*/
int
pqPutMsgStart(char msg_type, bool force_len, PGconn *conn)
{
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? */
if (force_len || PG_PROTOCOL_MAJOR(conn->pversion) >= 3)
{
lenPos = endPos;
/* allow room for message length */
endPos += 4;
}
else
lenPos = -1;
/* 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 */
if (conn->Pfdebug)
fprintf(conn->Pfdebug, "To backend> Msg %c\n",
msg_type ? msg_type : ' ');
return 0;
}
/*
* pqPutMsgBytes: add bytes to a partially-constructed message
*
* Returns 0 on success, EOF on error
*/
static int
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;
}
/**
* Same as pqPutMsgEnd except that data is NEVER flushed.
*/
void
pqPutMsgEndNoAutoFlush(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 = pg_hton32(msgLen);
memcpy(conn->outBuffer + conn->outMsgStart, &msgLen, 4);
}
/* Make message eligible to send */
conn->outCount = conn->outMsgEnd;
}
/*
* 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)
{
pqPutMsgEndNoAutoFlush(conn);
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 == PGINVALID_SOCKET)
{
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 + (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)
{
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
/* 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)
{
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
/* 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:
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"));
/* 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;
}
/*
* 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.
*
* Upon write failure, conn->write_failed is set and the error message is
* saved in conn->write_err_msg, but we clear the output buffer and return
* zero anyway; this is because callers should soldier on until it's possible
* to read from the server and check for an error message. write_err_msg
* should be reported only when we are unable to obtain a server error first.
* (Thus, a -1 result is returned only for an internal *read* failure.)
*/
static int
pqSendSome(PGconn *conn, int len)
{
char *ptr = conn->outBuffer;
int remaining = conn->outCount;
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.
*/
if (conn->write_failed)
{
/* conn->write_err_msg should be set up already */
conn->outCount = 0;
return 0;
}
if (conn->sock == PGINVALID_SOCKET)
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("connection not open\n"));
conn->write_failed = true;
/* Transfer error message to conn->write_err_msg, if possible */
/* (strdup failure is OK, we'll cope later) */
conn->write_err_msg = strdup(conn->errorMessage.data);
resetPQExpBuffer(&conn->errorMessage);
/* 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).
*
* Note: this assumes that pqsecure_write and its children
* will overwrite not append to conn->errorMessage. If
* that's ever changed, we could remember the length of
* conn->errorMessage at entry to this routine, and then
* save and delete just what was appended.
*/
conn->write_err_msg = strdup(conn->errorMessage.data);
resetPQExpBuffer(&conn->errorMessage);
/* Discard queued data; no chance it'll ever be sent */
conn->outCount = 0;
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)
{
if (conn->outBuffer_shared)
conn->outBuffer = ptr;
else
memmove(conn->outBuffer, ptr, remaining);
}
conn->outCount = remaining;
/* Once we finish with the external buffer, switch back to the original. */
if (remaining == 0 && conn->outBuffer_shared)
{
conn->outBuffer_shared = false;
conn->outBuffer = conn->outBufferSaved;
}
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.
* (See pqSendSome comments about how failure should be handled.)
*/
int
pqFlush(PGconn *conn)
{
if (conn->Pfdebug)
fflush(conn->Pfdebug);
if (conn->outCount > 0)
return pqSendSome(conn, conn->outCount);
return 0;
}
/*
* pqFlushNonBlocking:
*
* wrapper for pqFlush, used by the dispatcher.
* conn will be temporarily set to non-blocking mode,
* so that if not all data could be sent on 1st attempt,
* pqFlushNonBlocking will return 1 instead of waiting/retrying.
*
* Return 0 on success, -1 on failure and 1 when not all data could be sent
*/
int
pqFlushNonBlocking(PGconn *conn)
{
int ret;
bool old = conn->nonblocking;
conn->nonblocking = true;
ret = pqFlush(conn);
conn->nonblocking = old;
return ret;
}
/*
* 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.
*
* finish_time = ((time_t) -1) disables the wait limit.
*
* Returns -1 on failure, 0 if the socket is readable/writable, 1 if it timed out.
*/
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 -1; /* errorMessage is already set */
if (result == 0)
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("timeout expired\n"));
return 1;
}
return 0;
}
/*
* pgWaitTimeout: wait, but not past finish_time.
* wrapper for pqSocketCheck.
*
* finish_time = ((time_t) -1) disables the wait limit.
*/
int
pqWaitTimeout(int forRead, int forWrite, PGconn *conn, time_t finish_time)
{
int result;
result = pqSocketCheck(conn, forRead, forWrite, finish_time);
if (result == 0)
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("timeout expired\n"));
}
return result;
}
/*
* 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 == PGINVALID_SOCKET)
{
printfPQExpBuffer(&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];
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("select() failed: %s\n"),
SOCK_STRERROR(SOCK_ERRNO, sebuf, sizeof(sebuf)));
}
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 character beginning at s, using the
* specified encoding.
*/
int
PQmblen(const char *s, int encoding)
{
return pg_encoding_mblen(encoding, s);
}
/*
* returns the display length of the character beginning at s, using the
* specified encoding.
*/
int
PQdsplen(const char *s, int encoding)
{
return pg_encoding_dsplen(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);
if (encoding < 0)
encoding = PG_SQL_ASCII;
}
return encoding;
}
#ifdef ENABLE_NLS
static void
libpq_binddomain()
{
static bool already_bound = false;
if (!already_bound)
{
/* bindtextdomain() does not preserve errno */
#ifdef WIN32
int save_errno = GetLastError();
#else
int save_errno = errno;
#endif
const char *ldir;
already_bound = true;
/* No relocatable lookup here because the binary could be anywhere */
ldir = getenv("PGLOCALEDIR");
if (!ldir)
ldir = LOCALEDIR;
bindtextdomain(PG_TEXTDOMAIN("libpq"), ldir);
#ifdef WIN32
SetLastError(save_errno);
#else
errno = save_errno;
#endif
}
}
char *
libpq_gettext(const char *msgid)
{
libpq_binddomain();
return dgettext(PG_TEXTDOMAIN("libpq"), msgid);
}
char *
libpq_ngettext(const char *msgid, const char *msgid_plural, unsigned long n)
{
libpq_binddomain();
return dngettext(PG_TEXTDOMAIN("libpq"), msgid, msgid_plural, n);
}
#endif /* ENABLE_NLS */
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