os_unix.c

php-4.4.7学习linux时下载的源代码

		FD_SET(fd, &readFdSetPost);
		FD_CLR(fd, &readFdSet);
	    }

            if(FD_ISSET(fd, &writeFdSetCpy)) {
	        numWrPosted++;
	        FD_SET(fd, &writeFdSetPost);
		FD_CLR(fd, &writeFdSet);
	    }
        }
    }

    if(numRdPosted == 0 && numWrPosted == 0)
        return 0;

    for(fd = 0; fd <= maxFd; fd++) {
        /*
	 * Do reads and dispatch callback.
	 */
        if(FD_ISSET(fd, &readFdSetPost)
	   && asyncIoTable[AIO_RD_IX(fd)].inUse) {

	    numRdPosted--;
	    FD_CLR(fd, &readFdSetPost);
	    aioPtr = &asyncIoTable[AIO_RD_IX(fd)];

	    len = read(aioPtr->fd, aioPtr->buf, aioPtr->len);

	    procPtr = aioPtr->procPtr;
	    aioPtr->procPtr = NULL;
	    clientData = aioPtr->clientData;
	    aioPtr->inUse = 0;

	    (*procPtr)(clientData, len);
	}

        /*
	 * Do writes and dispatch callback.
	 */
        if(FD_ISSET(fd, &writeFdSetPost) &&
           asyncIoTable[AIO_WR_IX(fd)].inUse) {

	    numWrPosted--;
	    FD_CLR(fd, &writeFdSetPost);
	    aioPtr = &asyncIoTable[AIO_WR_IX(fd)];

	    len = write(aioPtr->fd, aioPtr->buf, aioPtr->len);

	    procPtr = aioPtr->procPtr;
	    aioPtr->procPtr = NULL;
	    clientData = aioPtr->clientData;
	    aioPtr->inUse = 0;
	    (*procPtr)(clientData, len);
	}
    }
    return 0;
}

/* 
 * Not all systems have strdup().  
 * @@@ autoconf should determine whether or not this is needed, but for now..
 */
static char * str_dup(const char * str)
{
    char * sdup = (char *) malloc(strlen(str) + 1);

    if (sdup)
        strcpy(sdup, str);

    return sdup;
}

/*
 *----------------------------------------------------------------------
 *
 * ClientAddrOK --
 *
 *      Checks if a client address is in a list of allowed addresses
 *
 * Results:
 *	TRUE if address list is empty or client address is present
 *      in the list, FALSE otherwise.
 *
 *----------------------------------------------------------------------
 */
static int ClientAddrOK(struct sockaddr_in *saPtr, const char *clientList)
{
    int result = FALSE;
    char *clientListCopy, *cur, *next;

    if (clientList == NULL || *clientList == '\0') {
        return TRUE;
    }

    clientListCopy = str_dup(clientList);

    for (cur = clientListCopy; cur != NULL; cur = next) {
        next = strchr(cur, ',');
        if (next != NULL) {
            *next++ = '\0';
        }
        if (inet_addr(cur) == saPtr->sin_addr.s_addr) {
            result = TRUE;
            break;
        }
    }

    free(clientListCopy);
    return result;
}

/*
 *----------------------------------------------------------------------
 *
 * AcquireLock --
 *
 *      On platforms that implement concurrent calls to accept
 *      on a shared listening ipcFd, returns 0.  On other platforms,
 *	acquires an exclusive lock across all processes sharing a
 *      listening ipcFd, blocking until the lock has been acquired.
 *
 * Results:
 *      0 for successful call, -1 in case of system error (fatal).
 *
 * Side effects:
 *      This process now has the exclusive lock.
 *
 *----------------------------------------------------------------------
 */
static int AcquireLock(int sock, int fail_on_intr)
{
#ifdef USE_LOCKING
    do {
        struct flock lock;
        lock.l_type = F_WRLCK;
        lock.l_start = 0;
        lock.l_whence = SEEK_SET;
        lock.l_len = 0;

        if (fcntl(sock, F_SETLKW, &lock) != -1)
            return 0;
    } while (errno == EINTR 
             && ! fail_on_intr 
             && ! shutdownPending);

    return -1;

#else
    return 0;
#endif
}

/*
 *----------------------------------------------------------------------
 *
 * ReleaseLock --
 *
 *      On platforms that implement concurrent calls to accept
 *      on a shared listening ipcFd, does nothing.  On other platforms,
 *	releases an exclusive lock acquired by AcquireLock.
 *
 * Results:
 *      0 for successful call, -1 in case of system error (fatal).
 *
 * Side effects:
 *      This process no longer holds the lock.
 *
 *----------------------------------------------------------------------
 */
static int ReleaseLock(int sock)
{
#ifdef USE_LOCKING
    do {
        struct flock lock;
        lock.l_type = F_UNLCK;
        lock.l_start = 0;
        lock.l_whence = SEEK_SET;
        lock.l_len = 0;

        if (fcntl(sock, F_SETLK, &lock) != -1)
            return 0;
    } while (errno == EINTR);

    return -1;

#else
    return 0;
#endif
}

/**********************************************************************
 * Determine if the errno resulting from a failed accept() warrants a
 * retry or exit().  Based on Apache's http_main.c accept() handling
 * and Stevens' Unix Network Programming Vol 1, 2nd Ed, para. 15.6.
 */
static int is_reasonable_accept_errno (const int error)
{
    switch (error) {
#ifdef EPROTO
        /* EPROTO on certain older kernels really means ECONNABORTED, so
         * we need to ignore it for them.  See discussion in new-httpd
         * archives nh.9701 search for EPROTO.  Also see nh.9603, search
         * for EPROTO:  There is potentially a bug in Solaris 2.x x<6, and
         * other boxes that implement tcp sockets in userland (i.e. on top of
         * STREAMS).  On these systems, EPROTO can actually result in a fatal
         * loop.  See PR#981 for example.  It's hard to handle both uses of
         * EPROTO. */
        case EPROTO:
#endif
#ifdef ECONNABORTED
        case ECONNABORTED:
#endif
        /* Linux generates the rest of these, other tcp stacks (i.e.
         * bsd) tend to hide them behind getsockopt() interfaces.  They
         * occur when the net goes sour or the client disconnects after the
         * three-way handshake has been done in the kernel but before
         * userland has picked up the socket. */
#ifdef ECONNRESET
        case ECONNRESET:
#endif
#ifdef ETIMEDOUT
        case ETIMEDOUT:
#endif
#ifdef EHOSTUNREACH
        case EHOSTUNREACH:
#endif
#ifdef ENETUNREACH
        case ENETUNREACH:
#endif
            return 1;

        default:
            return 0;
    }
}

/**********************************************************************
 * This works around a problem on Linux 2.0.x and SCO Unixware (maybe
 * others?).  When a connect() is made to a Unix Domain socket, but its
 * not accept()ed before the web server gets impatient and close()s, an
 * accept() results in a valid file descriptor, but no data to read.
 * This causes a block on the first read() - which never returns!
 *
 * Another approach to this is to write() to the socket to provoke a
 * SIGPIPE, but this is a pain because of the FastCGI protocol, the fact
 * that whatever is written has to be universally ignored by all FastCGI
 * web servers, and a SIGPIPE handler has to be installed which returns
 * (or SIGPIPE is ignored).
 *
 * READABLE_UNIX_FD_DROP_DEAD_TIMEVAL = 2,0 by default.
 *
 * Making it shorter is probably safe, but I'll leave that to you.  Making
 * it 0,0 doesn't work reliably.  The shorter you can reliably make it,
 * the faster your application will be able to recover (waiting 2 seconds
 * may _cause_ the problem when there is a very high demand). At any rate,
 * this is better than perma-blocking.
 */
static int is_af_unix_keeper(const int fd)
{
    struct timeval tval = { READABLE_UNIX_FD_DROP_DEAD_TIMEVAL };
    fd_set read_fds;

    FD_ZERO(&read_fds);
    FD_SET(fd, &read_fds);

    return select(fd + 1, &read_fds, NULL, NULL, &tval) >= 0 && FD_ISSET(fd, &read_fds);
}

/*
 *----------------------------------------------------------------------
 *
 * OS_Accept --
 *
 *	Accepts a new FastCGI connection.  This routine knows whether
 *      we're dealing with TCP based sockets or NT Named Pipes for IPC.
 *
 * Results:
 *      -1 if the operation fails, otherwise this is a valid IPC fd.
 *
 * Side effects:
 *      New IPC connection is accepted.
 *
 *----------------------------------------------------------------------
 */
int OS_Accept(int listen_sock, int fail_on_intr, const char *webServerAddrs)
{
    int socket = -1;
    union {
        struct sockaddr_un un;
        struct sockaddr_in in;
    } sa;

    for (;;) {
        if (AcquireLock(listen_sock, fail_on_intr))
            return -1;

        for (;;) {
            do {
#ifdef HAVE_SOCKLEN
                socklen_t len = sizeof(sa);
#else
                int len = sizeof(sa);
#endif
                if (shutdownPending) break;
                /* There's a window here */

                socket = accept(listen_sock, (struct sockaddr *)&sa, &len);
            } while (socket < 0 
                     && errno == EINTR 
                     && ! fail_on_intr 
                     && ! shutdownPending);

            if (socket < 0) {
                if (shutdownPending || ! is_reasonable_accept_errno(errno)) {
                    int errnoSave = errno;

                    ReleaseLock(listen_sock);
                    
                    if (! shutdownPending) {
                        errno = errnoSave;
                    }

                    return (-1);
                }
                errno = 0;
            }
            else {  /* socket >= 0 */
                int set = 1;

                if (sa.in.sin_family != AF_INET)
                    break;

#ifdef TCP_NODELAY
                /* No replies to outgoing data, so disable Nagle */
                setsockopt(socket, IPPROTO_TCP, TCP_NODELAY, (char *)&set, sizeof(set));
#endif

                /* Check that the client IP address is approved */
                if (ClientAddrOK(&sa.in, webServerAddrs))
                    break;

                close(socket);
            }  /* socket >= 0 */
        }  /* for(;;) */

        if (ReleaseLock(listen_sock))
            return (-1);

        if (sa.in.sin_family != AF_UNIX || is_af_unix_keeper(socket))
            break;

        close(socket);
    }  /* while(1) - lock */

    return (socket);
}

/*
 *----------------------------------------------------------------------
 *
 * OS_IpcClose
 *
 *	OS IPC routine to close an IPC connection.
 *
 * Results:
 *
 *
 * Side effects:
 *      IPC connection is closed.
 *
 *----------------------------------------------------------------------
 */
int OS_IpcClose(int ipcFd, int shutdown)
{
    return OS_Close(ipcFd, shutdown);
}

/*
 *----------------------------------------------------------------------
 *
 * OS_IsFcgi --
 *
 *	Determines whether this process is a FastCGI process or not.
 *
 * Results:
 *      Returns 1 if FastCGI, 0 if not.
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */
int OS_IsFcgi(int sock)
{
	union {
        struct sockaddr_in in;
        struct sockaddr_un un;
    } sa;
#ifdef HAVE_SOCKLEN
    socklen_t len = sizeof(sa);
#else
    int len = sizeof(sa);
#endif

    errno = 0;

    if (getpeername(sock, (struct sockaddr *)&sa, &len) != 0 && errno == ENOTCONN) {
        return TRUE;
    }
    else {
        return FALSE;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * OS_SetFlags --
 *
 *      Sets selected flag bits in an open file descriptor.
 *
 *----------------------------------------------------------------------
 */
void OS_SetFlags(int fd, int flags)
{
    int val;
    if((val = fcntl(fd, F_GETFL, 0)) < 0) {
        return;
    }
    val |= flags;
    if(fcntl(fd, F_SETFL, val) < 0) {
        return;
    }
}