/*------------------------------------------------------------------------- * * 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) 1996-2009, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * Portions Copyright (c) 2010-2012 Postgres-XC Development Group * * IDENTIFICATION * $PostgreSQL: pgsql/src/interfaces/libpq/fe-misc.c,v 1.137 2008/12/11 07:34:09 petere Exp $ * *------------------------------------------------------------------------- */ #include "gtm/gtm_c.h" #include #include #include #include #include #include #include #include #include #include "gtm/libpq-fe.h" #include "gtm/libpq-int.h" static int gtmpqPutMsgBytes(const void *buf, size_t len, GTM_Conn *conn); static int gtmpqSendSome(GTM_Conn *conn, int len); static int gtmpqSocketCheck(GTM_Conn *conn, int forRead, int forWrite, time_t end_time); static int gtmpqSocketPoll(int sock, int forRead, int forWrite, time_t end_time); /* * gtmpqGetc: 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 gtmpqGetc(char *result, GTM_Conn *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; } /* * gtmpqPutc: write 1 char to the current message */ int gtmpqPutc(char c, GTM_Conn *conn) { if (gtmpqPutMsgBytes(&c, 1, conn)) return EOF; if (conn->Pfdebug) fprintf(conn->Pfdebug, "To backend> %c\n", c); return 0; } /* * gtmpqGets[_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 gtmpqGets_internal(PQExpBuffer buf, GTM_Conn *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) resetGTMPQExpBuffer(buf); appendBinaryGTMPQExpBuffer(buf, inBuffer + conn->inCursor, slen); conn->inCursor = ++inCursor; if (conn->Pfdebug) fprintf(conn->Pfdebug, "From backend> \"%s\"\n", buf->data); return 0; } int gtmpqGets(PQExpBuffer buf, GTM_Conn *conn) { return gtmpqGets_internal(buf, conn, true); } int gtmpqGets_append(PQExpBuffer buf, GTM_Conn *conn) { return gtmpqGets_internal(buf, conn, false); } /* * gtmpqPuts: write a null-terminated string to the current message */ int gtmpqPuts(const char *s, GTM_Conn *conn) { if (gtmpqPutMsgBytes(s, strlen(s) + 1, conn)) return EOF; if (conn->Pfdebug) fprintf(conn->Pfdebug, "To backend> \"%s\"\n", s); return 0; } /* * gtmpqGetnchar: * get a string of exactly len bytes in buffer s, no null termination */ int gtmpqGetnchar(char *s, size_t len, GTM_Conn *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)> %.*s\n", (unsigned long) len, (int) len, s); return 0; } /* * gtmpqPutnchar: * write exactly len bytes to the current message */ int gtmpqPutnchar(const char *s, size_t len, GTM_Conn *conn) { if (gtmpqPutMsgBytes(s, len, conn)) return EOF; if (conn->Pfdebug) fprintf(conn->Pfdebug, "To backend> %.*s\n", (int) len, s); return 0; } /* * gtmpqGetInt * read a 2 or 4 byte integer and convert from network byte order * to local byte order */ int gtmpqGetInt(int *result, size_t bytes, GTM_Conn *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) ntohs(tmp2); break; case 4: if (conn->inCursor + 4 > conn->inEnd) return EOF; memcpy(&tmp4, conn->inBuffer + conn->inCursor, 4); conn->inCursor += 4; *result = (int) ntohl(tmp4); break; default: fprintf(conn->Pfdebug, "Integer size of (%ld) bytes not supported", bytes); return EOF; } if (conn->Pfdebug) fprintf(conn->Pfdebug, "From backend (#%lu)> %d\n", (unsigned long) bytes, *result); return 0; } /* * gtmpqPutInt * write an integer of 2 or 4 bytes, converting from host byte order * to network byte order. */ int gtmpqPutInt(int value, size_t bytes, GTM_Conn *conn) { uint16 tmp2; uint32 tmp4; switch (bytes) { case 2: tmp2 = htons((uint16) value); if (gtmpqPutMsgBytes((const char *) &tmp2, 2, conn)) return EOF; break; case 4: tmp4 = htonl((uint32) value); if (gtmpqPutMsgBytes((const char *) &tmp4, 4, conn)) return EOF; break; default: fprintf(conn->Pfdebug, "Integer size of (%ld) bytes not supported", 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 gtmpqCheckOutBufferSpace(size_t bytes_needed, GTM_Conn *conn) { int newsize = conn->outBufSize; char *newbuf; 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 */ printfGTMPQExpBuffer(&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 gtmpqCheckInBufferSpace(size_t bytes_needed, GTM_Conn *conn) { int newsize = conn->inBufSize; char *newbuf; 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 */ printfGTMPQExpBuffer(&conn->errorMessage, "cannot allocate memory for input buffer\n"); return EOF; } /* * gtmpqPutMsgStart: 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 gtmpqPutMsgStart(char msg_type, bool force_len, GTM_Conn *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) { lenPos = endPos; /* allow room for message length */ endPos += 4; } else lenPos = -1; /* make sure there is room for message header */ if (gtmpqCheckOutBufferSpace(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 gtmpqPutMsgEnd */ if (conn->Pfdebug) fprintf(conn->Pfdebug, "To backend> Msg %c\n", msg_type ? msg_type : ' '); return 0; } /* * gtmpqPutMsgBytes: add bytes to a partially-constructed message * * Returns 0 on success, EOF on error */ static int gtmpqPutMsgBytes(const void *buf, size_t len, GTM_Conn *conn) { /* make sure there is room for it */ if (gtmpqCheckOutBufferSpace(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; } /* * gtmpqPutMsgEnd: 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 gtmpqFlush * when it's important to flush all the data out to the server. */ int gtmpqPutMsgEnd(GTM_Conn *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 (gtmpqSendSome(conn, toSend) < 0) return EOF; /* in nonblock mode, don't complain if unable to send it all */ } return 0; } /* ---------- * gtmpqReadData: 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 gtmpqReadData(GTM_Conn *conn) { int someread = 0; int nread; if (conn->sock < 0) { printfGTMPQExpBuffer(&conn->errorMessage, "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 (gtmpqCheckInBufferSpace(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 = recv(conn->sock, conn->inBuffer + conn->inEnd, conn->inBufSize - conn->inEnd, 0); conn->last_call = GTM_LastCall_RECV; if (nread < 0) { conn->last_errno = SOCK_ERRNO; 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 printfGTMPQExpBuffer(&conn->errorMessage, "could not receive data from server:\n"); return -1; } else conn->last_errno = 0; 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 ... */ #ifdef NOT_USED if (conn->inEnd > 32768 && (conn->inBufSize - conn->inEnd) >= 8192) { someread = 1; goto retry3; } #endif 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 gtmpqReadReady() test. So we must * play dumb and assume there is more data, relying on the SSL layer to * detect true EOF. */ switch (gtmpqReadReady(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 = recv(conn->sock, conn->inBuffer + conn->inEnd, conn->inBufSize - conn->inEnd, 0); conn->last_call = GTM_LastCall_RECV; if (nread < 0) { conn->last_errno = SOCK_ERRNO; 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 printfGTMPQExpBuffer(&conn->errorMessage, "could not receive data from server: \n"); return -1; } else conn->last_errno = 0; 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: printfGTMPQExpBuffer(&conn->errorMessage, "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 */ close(conn->sock); conn->sock = -1; return -1; } /* * gtmpqSendSome: 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 gtmpqSendSome(GTM_Conn *conn, int len) { char *ptr = conn->outBuffer; int remaining = conn->outCount; int result = 0; if (conn->sock < 0) { printfGTMPQExpBuffer(&conn->errorMessage, "connection not open\n"); return -1; } /* while there's still data to send */ while (len > 0) { int sent; sent = send(conn->sock, ptr, len, 0); conn->last_call = GTM_LastCall_SEND; if (sent < 0) { conn->last_errno = SOCK_ERRNO; /* * Anything except EAGAIN/EWOULDBLOCK/EINTR 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 printfGTMPQExpBuffer(&conn->errorMessage, "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 * gtmpqReadData finds no more data can be read. But abandon * attempt to send data. */ conn->outCount = 0; return -1; default: printfGTMPQExpBuffer(&conn->errorMessage, "could not send data to server: \n"); /* We don't assume it's a fatal error... */ conn->outCount = 0; return -1; } } else { ptr += sent; len -= sent; remaining -= sent; conn->last_errno = 0; } if (len > 0) { /* * We didn't send it all, wait till we can send more. * * If the connection is in non-blocking mode we don't wait, but * return 1 to indicate that data is still pending. */ result = 1; break; } } /* shift the remaining contents of the buffer */ if (remaining > 0) memmove(conn->outBuffer, ptr, remaining); conn->outCount = remaining; return result; } /* * gtmpqFlush: 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 gtmpqFlush(GTM_Conn *conn) { if (conn->Pfdebug) fflush(conn->Pfdebug); if (conn->outCount > 0) return gtmpqSendSome(conn, conn->outCount); return 0; } /* * gtmpqWait: 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 gtmpqWait(int forRead, int forWrite, GTM_Conn *conn) { return gtmpqWaitTimed(forRead, forWrite, conn, (time_t) -1); } /* * gtmpqWaitTimed: 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 gtmpqWaitTimed(int forRead, int forWrite, GTM_Conn *conn, time_t finish_time) { int result; result = gtmpqSocketCheck(conn, forRead, forWrite, finish_time); if (result < 0) return EOF; /* errorMessage is already set */ if (result == 0) { printfGTMPQExpBuffer(&conn->errorMessage, "timeout expired\n"); return EOF; } return 0; } /* * gtmpqReadReady: is select() saying the file is ready to read? * Returns -1 on failure, 0 if not ready, 1 if ready. */ int gtmpqReadReady(GTM_Conn *conn) { return gtmpqSocketCheck(conn, 1, 0, (time_t) 0); } /* * gtmpqWriteReady: is select() saying the file is ready to write? * Returns -1 on failure, 0 if not ready, 1 if ready. */ int gtmpqWriteReady(GTM_Conn *conn) { return gtmpqSocketCheck(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 gtmpqSocketCheck(GTM_Conn *conn, int forRead, int forWrite, time_t end_time) { int result; if (!conn) return -1; if (conn->sock < 0) { printfGTMPQExpBuffer(&conn->errorMessage, "socket not open\n"); return -1; } /* We will retry as long as we get EINTR */ do result = gtmpqSocketPoll(conn->sock, forRead, forWrite, end_time); while (result < 0 && SOCK_ERRNO == EINTR); if (result < 0) printfGTMPQExpBuffer(&conn->errorMessage, "select() failed: \n"); 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 gtmpqSocketPoll(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 */ }