typedef enum {
MEM_READ,
- MEM_WRITE,
+ MEM_WRITE
} memc_read_or_write;
static ssize_t io_flush(memcached_server_st *ptr, memcached_return *error);
+static void increment_udp_message_id(memcached_server_st *ptr);
static memcached_return io_wait(memcached_server_st *ptr,
memc_read_or_write read_or_write)
{
- struct pollfd fds[1];
- short flags= 0;
+ struct pollfd fds= {
+ .fd= ptr->fd,
+ .events = POLLIN
+ };
int error;
- if (read_or_write == MEM_WRITE) /* write */
- flags= POLLOUT | POLLERR;
- else
- flags= POLLIN | POLLERR;
-
- memset(&fds, 0, sizeof(struct pollfd));
- fds[0].fd= ptr->fd;
- fds[0].events= flags;
+ unlikely (read_or_write == MEM_WRITE) /* write */
+ fds.events= POLLOUT;
/*
** We are going to block on write, but at least on Solaris we might block
** the test.
*/
if (read_or_write == MEM_WRITE)
- memcached_purge(ptr);
+ {
+ memcached_return rc= memcached_purge(ptr);
+ if (rc != MEMCACHED_SUCCESS && rc != MEMCACHED_STORED)
+ return MEMCACHED_FAILURE;
+ }
+
+ int timeout= ptr->root->poll_timeout;
+ if ((ptr->root->flags & MEM_NO_BLOCK) == 0)
+ timeout= -1;
- error= poll(fds, 1, ptr->root->poll_timeout);
+ error= poll(&fds, 1, timeout);
if (error == 1)
return MEMCACHED_SUCCESS;
else if (error == 0)
- {
return MEMCACHED_TIMEOUT;
- }
/* Imposssible for anything other then -1 */
WATCHPOINT_ASSERT(error == -1);
memcached_quit_server(ptr, 1);
return MEMCACHED_FAILURE;
+}
+/**
+ * Try to fill the input buffer for a server with as much
+ * data as possible.
+ *
+ * @param ptr the server to pack
+ */
+static bool repack_input_buffer(memcached_server_st *ptr)
+{
+ if (ptr->read_ptr != ptr->read_buffer)
+ {
+ /* Move all of the data to the beginning of the buffer so
+ ** that we can fit more data into the buffer...
+ */
+ memmove(ptr->read_buffer, ptr->read_ptr, ptr->read_buffer_length);
+ ptr->read_ptr= ptr->read_buffer;
+ ptr->read_data_length= ptr->read_buffer_length;
+ }
+
+ /* There is room in the buffer, try to fill it! */
+ if (ptr->read_buffer_length != MEMCACHED_MAX_BUFFER)
+ {
+ /* Just try a single read to grab what's available */
+ ssize_t nr= read(ptr->fd,
+ ptr->read_ptr + ptr->read_data_length,
+ MEMCACHED_MAX_BUFFER - ptr->read_data_length);
+
+ if (nr > 0)
+ {
+ ptr->read_data_length+= (size_t)nr;
+ ptr->read_buffer_length+= (size_t)nr;
+ return true;
+ }
+ }
+ return false;
+}
+
+/**
+ * If the we have callbacks connected to this server structure
+ * we may start process the input queue and fire the callbacks
+ * for the incomming messages. This function is _only_ called
+ * when the input buffer is full, so that we _know_ that we have
+ * at least _one_ message to process.
+ *
+ * @param ptr the server to star processing iput messages for
+ * @return true if we processed anything, false otherwise
+ */
+static bool process_input_buffer(memcached_server_st *ptr)
+{
+ /*
+ ** We might be able to process some of the response messages if we
+ ** have a callback set up
+ */
+ if (ptr->root->callbacks != NULL && (ptr->root->flags & MEM_USE_UDP) == 0)
+ {
+ /*
+ * We might have responses... try to read them out and fire
+ * callbacks
+ */
+ memcached_callback_st cb= *ptr->root->callbacks;
+
+ char buffer[MEMCACHED_DEFAULT_COMMAND_SIZE];
+ memcached_return error;
+ error= memcached_response(ptr, buffer, sizeof(buffer),
+ &ptr->root->result);
+ if (error == MEMCACHED_SUCCESS)
+ {
+ for (unsigned int x= 0; x < cb.number_of_callback; x++)
+ {
+ error= (*cb.callback[x])(ptr->root, &ptr->root->result, cb.context);
+ if (error != MEMCACHED_SUCCESS)
+ break;
+ }
+
+ /* @todo what should I do with the error message??? */
+ }
+ /* @todo what should I do with other error messages?? */
+ return true;
+ }
+
+ return false;
}
#ifdef UNUSED
}
#endif
-ssize_t memcached_io_read(memcached_server_st *ptr,
- void *buffer, size_t length)
+memcached_return memcached_io_read(memcached_server_st *ptr,
+ void *buffer, size_t length, ssize_t *nread)
{
char *buffer_ptr;
while (length)
{
- uint8_t found_eof= 0;
if (!ptr->read_buffer_length)
{
ssize_t data_read;
while (1)
{
- data_read= read(ptr->fd,
- ptr->read_buffer,
- MEMCACHED_MAX_BUFFER);
+ data_read= read(ptr->fd, ptr->read_buffer, MEMCACHED_MAX_BUFFER);
if (data_read > 0)
break;
else if (data_read == -1)
{
ptr->cached_errno= errno;
+ memcached_return rc= MEMCACHED_UNKNOWN_READ_FAILURE;
switch (errno)
{
case EAGAIN:
- {
- memcached_return rc;
-
- rc= io_wait(ptr, MEM_READ);
+ case EINTR:
+ if ((rc= io_wait(ptr, MEM_READ)) == MEMCACHED_SUCCESS)
+ continue;
+ /* fall through */
- if (rc == MEMCACHED_SUCCESS)
- continue;
- }
- /* fall trough */
default:
{
memcached_quit_server(ptr, 1);
- return -1;
+ *nread= -1;
+ return rc;
}
}
}
else
{
- found_eof= 1;
- break;
+ /*
+ EOF. Any data received so far is incomplete
+ so discard it. This always reads by byte in case of TCP
+ and protocol enforcement happens at memcached_response()
+ looking for '\n'. We do not care for UDB which requests 8 bytes
+ at once. Generally, this means that connection went away. Since
+ for blocking I/O we do not return 0 and for non-blocking case
+ it will return EGAIN if data is not immediatly available.
+ */
+ memcached_quit_server(ptr, 1);
+ *nread= -1;
+ return MEMCACHED_UNKNOWN_READ_FAILURE;
}
}
ptr->io_bytes_sent = 0;
- ptr->read_data_length= data_read;
- ptr->read_buffer_length= data_read;
+ ptr->read_data_length= (size_t) data_read;
+ ptr->read_buffer_length= (size_t) data_read;
ptr->read_ptr= ptr->read_buffer;
}
buffer_ptr++;
break;
}
-
- if (found_eof)
- break;
}
- return (size_t)(buffer_ptr - (char*)buffer);
+ ptr->server_failure_counter= 0;
+ *nread = (ssize_t)(buffer_ptr - (char*)buffer);
+ return MEMCACHED_SUCCESS;
}
ssize_t memcached_io_write(memcached_server_st *ptr,
size_t original_length;
const char* buffer_ptr;
+ WATCHPOINT_ASSERT(ptr->fd != -1);
+
original_length= length;
buffer_ptr= buffer;
{
char *write_ptr;
size_t should_write;
+ size_t buffer_end;
- should_write= MEMCACHED_MAX_BUFFER - ptr->write_buffer_offset;
- write_ptr= ptr->write_buffer + ptr->write_buffer_offset;
-
- should_write= (should_write < length) ? should_write : length;
+ if (ptr->type == MEMCACHED_CONNECTION_UDP)
+ {
+ //UDP does not support partial writes
+ buffer_end= MAX_UDP_DATAGRAM_LENGTH;
+ should_write= length;
+ if (ptr->write_buffer_offset + should_write > buffer_end)
+ return -1;
+ }
+ else
+ {
+ buffer_end= MEMCACHED_MAX_BUFFER;
+ should_write= buffer_end - ptr->write_buffer_offset;
+ should_write= (should_write < length) ? should_write : length;
+ }
+ write_ptr= ptr->write_buffer + ptr->write_buffer_offset;
memcpy(write_ptr, buffer_ptr, should_write);
ptr->write_buffer_offset+= should_write;
buffer_ptr+= should_write;
length-= should_write;
- if (ptr->write_buffer_offset == MEMCACHED_MAX_BUFFER)
+ if (ptr->write_buffer_offset == buffer_end && ptr->type != MEMCACHED_CONNECTION_UDP)
{
memcached_return rc;
ssize_t sent_length;
+ WATCHPOINT_ASSERT(ptr->fd != -1);
sent_length= io_flush(ptr, &rc);
if (sent_length == -1)
return -1;
- WATCHPOINT_ASSERT(sent_length == MEMCACHED_MAX_BUFFER);
+ /* If io_flush calls memcached_purge, sent_length may be 0 */
+ unlikely (sent_length != 0)
+ {
+ WATCHPOINT_ASSERT(sent_length == (ssize_t)buffer_end);
+ }
}
}
if (with_flush)
{
memcached_return rc;
+ WATCHPOINT_ASSERT(ptr->fd != -1);
if (io_flush(ptr, &rc) == -1)
return -1;
}
- return original_length;
+ return (ssize_t) original_length;
}
memcached_return memcached_io_close(memcached_server_st *ptr)
return MEMCACHED_SUCCESS;
/* in case of death shutdown to avoid blocking at close() */
- r= shutdown(ptr->fd, SHUT_RDWR);
-
-#ifdef HAVE_DEBUG
- if (r && errno != ENOTCONN)
+ if (1)
{
- WATCHPOINT_NUMBER(ptr->fd);
- WATCHPOINT_ERRNO(errno);
- WATCHPOINT_ASSERT(errno);
- }
+ r= shutdown(ptr->fd, SHUT_RDWR);
+
+#ifdef DEBUG
+ if (r && errno != ENOTCONN)
+ {
+ WATCHPOINT_NUMBER(ptr->fd);
+ WATCHPOINT_ERRNO(errno);
+ WATCHPOINT_ASSERT(errno);
+ }
#endif
+ }
r= close(ptr->fd);
-#ifdef HAVE_DEBUG
+#ifdef DEBUG
if (r != 0)
WATCHPOINT_ERRNO(errno);
#endif
return MEMCACHED_SUCCESS;
}
+memcached_server_st *memcached_io_get_readable_server(memcached_st *memc)
+{
+#define MAX_SERVERS_TO_POLL 100
+ struct pollfd fds[MAX_SERVERS_TO_POLL];
+ unsigned int host_index= 0;
+
+ for (unsigned int x= 0;
+ x< memc->number_of_hosts && host_index < MAX_SERVERS_TO_POLL;
+ ++x)
+ {
+ if (memc->hosts[x].read_buffer_length > 0) /* I have data in the buffer */
+ return &memc->hosts[x];
+
+ if (memcached_server_response_count(&memc->hosts[x]) > 0)
+ {
+ fds[host_index].events = POLLIN;
+ fds[host_index].revents = 0;
+ fds[host_index].fd = memc->hosts[x].fd;
+ ++host_index;
+ }
+ }
+
+ if (host_index < 2)
+ {
+ /* We have 0 or 1 server with pending events.. */
+ for (unsigned int x= 0; x< memc->number_of_hosts; ++x)
+ if (memcached_server_response_count(&memc->hosts[x]) > 0)
+ return &memc->hosts[x];
+
+ return NULL;
+ }
+
+ int err= poll(fds, host_index, memc->poll_timeout);
+ switch (err) {
+ case -1:
+ memc->cached_errno = errno;
+ /* FALLTHROUGH */
+ case 0:
+ break;
+ default:
+ for (unsigned int x= 0; x < host_index; ++x)
+ if (fds[x].revents & POLLIN)
+ for (unsigned int y= 0; y < memc->number_of_hosts; ++y)
+ if (memc->hosts[y].fd == fds[x].fd)
+ return &memc->hosts[y];
+ }
+
+ return NULL;
+}
+
static ssize_t io_flush(memcached_server_st *ptr,
memcached_return *error)
{
+ /*
+ ** We might want to purge the input buffer if we haven't consumed
+ ** any output yet... The test for the limits is the purge is inline
+ ** in the purge function to avoid duplicating the logic..
+ */
+ {
+ memcached_return rc;
+ WATCHPOINT_ASSERT(ptr->fd != -1);
+ rc= memcached_purge(ptr);
+
+ if (rc != MEMCACHED_SUCCESS && rc != MEMCACHED_STORED)
+ return -1;
+ }
ssize_t sent_length;
size_t return_length;
char *local_write_ptr= ptr->write_buffer;
*error= MEMCACHED_SUCCESS;
- if (ptr->write_buffer_offset == 0)
+ WATCHPOINT_ASSERT(ptr->fd != -1);
+
+ // UDP Sanity check, make sure that we are not sending somthing too big
+ if (ptr->type == MEMCACHED_CONNECTION_UDP && write_length > MAX_UDP_DATAGRAM_LENGTH)
+ return -1;
+
+ if (ptr->write_buffer_offset == 0 || (ptr->type == MEMCACHED_CONNECTION_UDP
+ && ptr->write_buffer_offset == UDP_DATAGRAM_HEADER_LENGTH))
return 0;
/* Looking for memory overflows */
-#if defined(HAVE_DEBUG)
+#if defined(DEBUG)
if (write_length == MEMCACHED_MAX_BUFFER)
WATCHPOINT_ASSERT(ptr->write_buffer == local_write_ptr);
WATCHPOINT_ASSERT((ptr->write_buffer + MEMCACHED_MAX_BUFFER) >= (local_write_ptr + write_length));
return_length= 0;
while (write_length)
{
+ WATCHPOINT_ASSERT(ptr->fd != -1);
WATCHPOINT_ASSERT(write_length > 0);
sent_length= 0;
if (ptr->type == MEMCACHED_CONNECTION_UDP)
+ increment_udp_message_id(ptr);
+ sent_length= write(ptr->fd, local_write_ptr, write_length);
+
+ if (sent_length == -1)
{
- struct addrinfo *ai;
-
- ai= ptr->address_info;
-
- /* Crappy test code */
- char buffer[HUGE_STRING_LEN + 8];
- memset(buffer, 0, HUGE_STRING_LEN + 8);
- memcpy (buffer+8, local_write_ptr, write_length);
- buffer[0]= 0;
- buffer[1]= 0;
- buffer[2]= 0;
- buffer[3]= 0;
- buffer[4]= 0;
- buffer[5]= 1;
- buffer[6]= 0;
- buffer[7]= 0;
- sent_length= sendto(ptr->fd, buffer, write_length + 8, 0,
- (struct sockaddr *)ai->ai_addr,
- ai->ai_addrlen);
- if (sent_length == -1)
+ ptr->cached_errno= errno;
+ switch (errno)
{
- WATCHPOINT_ERRNO(errno);
- WATCHPOINT_ASSERT(0);
- }
- sent_length-= 8; /* We remove the header */
- }
- else
- {
- /*
- ** We might want to purge the input buffer if we haven't consumed
- ** any output yet... The test for the limits is the purge is inline
- ** in the purge function to avoid duplicating the logic..
- */
- memcached_purge(ptr);
-
- if ((sent_length= write(ptr->fd, local_write_ptr,
- write_length)) == -1)
+ case ENOBUFS:
+ continue;
+ case EAGAIN:
{
- switch (errno)
- {
- case ENOBUFS:
+ /*
+ * We may be blocked on write because the input buffer
+ * is full. Let's check if we have room in our input
+ * buffer for more data and retry the write before
+ * waiting..
+ */
+ if (repack_input_buffer(ptr) ||
+ process_input_buffer(ptr))
continue;
- case EAGAIN:
- {
- memcached_return rc;
- rc= io_wait(ptr, MEM_WRITE);
- if (rc == MEMCACHED_SUCCESS)
- continue;
+ memcached_return rc;
+ rc= io_wait(ptr, MEM_WRITE);
- memcached_quit_server(ptr, 1);
- return -1;
- }
- default:
- memcached_quit_server(ptr, 1);
- ptr->cached_errno= errno;
- *error= MEMCACHED_ERRNO;
- return -1;
- }
+ if (rc == MEMCACHED_SUCCESS || rc == MEMCACHED_TIMEOUT)
+ continue;
+
+ memcached_quit_server(ptr, 1);
+ return -1;
+ }
+ default:
+ memcached_quit_server(ptr, 1);
+ *error= MEMCACHED_ERRNO;
+ return -1;
}
}
- ptr->io_bytes_sent += sent_length;
+ if (ptr->type == MEMCACHED_CONNECTION_UDP &&
+ (size_t)sent_length != write_length)
+ {
+ memcached_quit_server(ptr, 1);
+ return -1;
+ }
+
+ ptr->io_bytes_sent += (uint32_t) sent_length;
local_write_ptr+= sent_length;
- write_length-= sent_length;
- return_length+= sent_length;
+ write_length-= (uint32_t) sent_length;
+ return_length+= (uint32_t) sent_length;
}
WATCHPOINT_ASSERT(write_length == 0);
// Need to study this assert() WATCHPOINT_ASSERT(return_length ==
// ptr->write_buffer_offset);
- ptr->write_buffer_offset= 0;
- return return_length;
+ // if we are a udp server, the begining of the buffer is reserverd for
+ // the upd frame header
+ if (ptr->type == MEMCACHED_CONNECTION_UDP)
+ ptr->write_buffer_offset= UDP_DATAGRAM_HEADER_LENGTH;
+ else
+ ptr->write_buffer_offset= 0;
+
+ return (ssize_t) return_length;
}
-/*
+/*
Eventually we will just kill off the server with the problem.
*/
void memcached_io_reset(memcached_server_st *ptr)
{
- memcached_quit_server(ptr, 0);
+ memcached_quit_server(ptr, 1);
+}
+
+/**
+ * Read a given number of bytes from the server and place it into a specific
+ * buffer. Reset the IO channel on this server if an error occurs.
+ */
+memcached_return memcached_safe_read(memcached_server_st *ptr,
+ void *dta,
+ size_t size)
+{
+ size_t offset= 0;
+ char *data= dta;
+
+ while (offset < size)
+ {
+ ssize_t nread;
+ memcached_return rc= memcached_io_read(ptr, data + offset, size - offset,
+ &nread);
+ if (rc != MEMCACHED_SUCCESS)
+ return rc;
+
+ offset+= (size_t) nread;
+ }
+
+ return MEMCACHED_SUCCESS;
+}
+
+memcached_return memcached_io_readline(memcached_server_st *ptr,
+ char *buffer_ptr,
+ size_t size)
+{
+ bool line_complete= false;
+ size_t total_nr= 0;
+
+ while (!line_complete)
+ {
+ if (ptr->read_buffer_length == 0)
+ {
+ /*
+ * We don't have any data in the buffer, so let's fill the read
+ * buffer. Call the standard read function to avoid duplicating
+ * the logic.
+ */
+ ssize_t nread;
+ memcached_return rc= memcached_io_read(ptr, buffer_ptr, 1, &nread);
+ if (rc != MEMCACHED_SUCCESS)
+ return rc;
+
+ if (*buffer_ptr == '\n')
+ line_complete= true;
+
+ ++buffer_ptr;
+ ++total_nr;
+ }
+
+ /* Now let's look in the buffer and copy as we go! */
+ while (ptr->read_buffer_length && total_nr < size && !line_complete)
+ {
+ *buffer_ptr = *ptr->read_ptr;
+ if (*buffer_ptr == '\n')
+ line_complete = true;
+ --ptr->read_buffer_length;
+ ++ptr->read_ptr;
+ ++total_nr;
+ ++buffer_ptr;
+ }
+
+ if (total_nr == size)
+ return MEMCACHED_PROTOCOL_ERROR;
+ }
+
+ return MEMCACHED_SUCCESS;
+}
+
+/*
+ * The udp request id consists of two seperate sections
+ * 1) The thread id
+ * 2) The message number
+ * The thread id should only be set when the memcached_st struct is created
+ * and should not be changed.
+ *
+ * The message num is incremented for each new message we send, this function
+ * extracts the message number from message_id, increments it and then
+ * writes the new value back into the header
+ */
+static void increment_udp_message_id(memcached_server_st *ptr)
+{
+ struct udp_datagram_header_st *header= (struct udp_datagram_header_st *)ptr->write_buffer;
+ uint16_t cur_req= get_udp_datagram_request_id(header);
+ int msg_num= get_msg_num_from_request_id(cur_req);
+ int thread_id= get_thread_id_from_request_id(cur_req);
+
+ if (((++msg_num) & UDP_REQUEST_ID_THREAD_MASK) != 0)
+ msg_num= 0;
+
+ header->request_id= htons((uint16_t) (thread_id | msg_num));
+}
+
+memcached_return memcached_io_init_udp_header(memcached_server_st *ptr, uint16_t thread_id)
+{
+ if (thread_id > UDP_REQUEST_ID_MAX_THREAD_ID)
+ return MEMCACHED_FAILURE;
+
+ struct udp_datagram_header_st *header= (struct udp_datagram_header_st *)ptr->write_buffer;
+ header->request_id= htons((uint16_t) (generate_udp_request_thread_id(thread_id)));
+ header->num_datagrams= htons(1);
+ header->sequence_number= htons(0);
+
+ return MEMCACHED_SUCCESS;
}
projects / m6w6 / libmemcached / blobdiff