diff options
Diffstat (limited to 'libpq/fe-misc.c')
-rw-r--r-- | libpq/fe-misc.c | 1267 |
1 files changed, 0 insertions, 1267 deletions
diff --git a/libpq/fe-misc.c b/libpq/fe-misc.c deleted file mode 100644 index 32da8ca..0000000 --- a/libpq/fe-misc.c +++ /dev/null @@ -1,1267 +0,0 @@ -/*------------------------------------------------------------------------- - * - * 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) 1996-2016, PostgreSQL Global Development Group - * Portions Copyright (c) 1994, Regents of the University of California - * - * IDENTIFICATION - * src/interfaces/libpq/fe-misc.c - * - *------------------------------------------------------------------------- - */ - -#include "postgres_fe.h" - -#include <signal.h> -#include <time.h> - -#include <netinet/in.h> -#include <arpa/inet.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_POLL_H -#include <sys/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 "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) 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: - 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; -} - -/* - * 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 = htons((uint16) value); - if (pqPutMsgBytes((const char *) &tmp2, 2, conn)) - return EOF; - break; - case 4: - tmp4 = htonl((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; -} - -/* - * pqPutMsgEnd: finish constructing a message and possibly send it - * - * Returns 0 on success, EOF on error - * - * We don't actually send anything here unless we've accumulated at least - * 8K worth of data (the typical size of a pipe buffer on Unix systems). - * This avoids sending small partial packets. The caller must use pqFlush - * when it's important to flush all the data out to the server. - */ -int -pqPutMsgEnd(PGconn *conn) -{ - if (conn->Pfdebug) - fprintf(conn->Pfdebug, "To backend> Msg complete, length %u\n", - conn->outMsgEnd - conn->outCount); - - /* Fill in length word if needed */ - if (conn->outMsgStart >= 0) - { - uint32 msgLen = conn->outMsgEnd - conn->outMsgStart; - - msgLen = htonl(msgLen); - memcpy(conn->outBuffer + conn->outMsgStart, &msgLen, 4); - } - - /* Make message eligible to send */ - conn->outCount = conn->outMsgEnd; - - if (conn->outCount >= 8192) - { - int toSend = conn->outCount - (conn->outCount % 8192); - - if (pqSendSome(conn, toSend) < 0) - return EOF; - /* in nonblock mode, don't complain if unable to send it all */ - } - - return 0; -} - -/* ---------- - * pqReadData: read more data, if any is available - * Possible return values: - * 1: successfully loaded at least one more byte - * 0: no data is presently available, but no error detected - * -1: error detected (including EOF = connection closure); - * conn->errorMessage set - * NOTE: callers must not assume that pointers or indexes into conn->inBuffer - * remain valid across this call! - * ---------- - */ -int -pqReadData(PGconn *conn) -{ - int someread = 0; - int nread; - - if (conn->sock == 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. - */ -static int -pqSendSome(PGconn *conn, int len) -{ - char *ptr = conn->outBuffer; - int remaining = conn->outCount; - int result = 0; - - if (conn->sock == PGINVALID_SOCKET) - { - printfPQExpBuffer(&conn->errorMessage, - libpq_gettext("connection not open\n")); - /* Discard queued data; no chance it'll ever be sent */ - conn->outCount = 0; - return -1; - } - - /* 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 */ - - /* - * We used to close the socket here, but that's a bad idea - * since there might be unread data waiting (typically, a - * NOTICE message from the backend telling us it's - * committing hara-kiri...). Leave the socket open until - * pqReadData finds no more data can be read. But abandon - * attempt to send data. - */ - conn->outCount = 0; - return -1; - } - } - 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.) - */ - 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; -} - - -/* - * pqFlush: send any data waiting in the output buffer - * - * Return 0 on success, -1 on failure and 1 when not all data could be sent - * because the socket would block and the connection is non-blocking. - */ -int -pqFlush(PGconn *conn) -{ - if (conn->Pfdebug) - fflush(conn->Pfdebug); - - if (conn->outCount > 0) - return pqSendSome(conn, conn->outCount); - - return 0; -} - - -/* - * pqWait: wait until we can read or write the connection socket - * - * JAB: If SSL enabled and used and forRead, buffered bytes short-circuit the - * call to select(). - * - * We also stop waiting and return if the kernel flags an exception condition - * on the socket. The actual error condition will be detected and reported - * when the caller tries to read or write the socket. - */ -int -pqWait(int forRead, int forWrite, PGconn *conn) -{ - return pqWaitTimed(forRead, forWrite, conn, (time_t) -1); -} - -/* - * pqWaitTimed: wait, but not past finish_time. - * - * If finish_time is exceeded then we return failure (EOF). This is like - * the response for a kernel exception because we don't want the caller - * to try to read/write in that case. - * - * finish_time = ((time_t) -1) disables the wait limit. - */ -int -pqWaitTimed(int forRead, int forWrite, PGconn *conn, time_t finish_time) -{ - int result; - - result = pqSocketCheck(conn, forRead, forWrite, finish_time); - - if (result < 0) - return EOF; /* errorMessage is already set */ - - if (result == 0) - { - printfPQExpBuffer(&conn->errorMessage, - libpq_gettext("timeout expired\n")); - return EOF; - } - - return 0; -} - -/* - * pqReadReady: is select() saying the file is ready to read? - * Returns -1 on failure, 0 if not ready, 1 if ready. - */ -int -pqReadReady(PGconn *conn) -{ - return pqSocketCheck(conn, 1, 0, (time_t) 0); -} - -/* - * pqWriteReady: is select() saying the file is ready to write? - * Returns -1 on failure, 0 if not ready, 1 if ready. - */ -int -pqWriteReady(PGconn *conn) -{ - return pqSocketCheck(conn, 0, 1, (time_t) 0); -} - -/* - * Checks a socket, using poll or select, for data to be read, written, - * or both. Returns >0 if one or more conditions are met, 0 if it timed - * out, -1 if an error occurred. - * - * If SSL is in use, the SSL buffer is checked prior to checking the socket - * for read data directly. - */ -static int -pqSocketCheck(PGconn *conn, int forRead, int forWrite, time_t end_time) -{ - int result; - - if (!conn) - return -1; - if (conn->sock == 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) > 0) - { - /* short-circuit the select */ - return 1; - } -#endif - - /* We will retry as long as we get EINTR */ - do - result = pqSocketPoll(conn->sock, forRead, forWrite, end_time); - while (result < 0 && SOCK_ERRNO == EINTR); - - if (result < 0) - { - char sebuf[256]; - - 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 */ |