X-Git-Url: https://git.m6w6.name/?a=blobdiff_plain;f=libmemcached%2Fmemcached_io.c;h=693ce95c54ddc052642acc7fd98137c54fb8ebbc;hb=a7a011c2ea4a63368b3a96a332da00820ed402cb;hp=72a02a0f97f52b030b3c1ab45cefa84b742c4bf4;hpb=c442af1afa9376ff660008f82b6217e577a36a73;p=m6w6%2Flibmemcached

diff --git a/libmemcached/memcached_io.c b/libmemcached/memcached_io.c
index 72a02a0f..693ce95c 100644
--- a/libmemcached/memcached_io.c
+++ b/libmemcached/memcached_io.c
@@ -9,26 +9,23 @@
 
 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
@@ -40,26 +37,109 @@ static memcached_return io_wait(memcached_server_st *ptr,
   */
   if (read_or_write == MEM_WRITE)
   {
-    memcached_return rc=memcached_purge(ptr);
+    memcached_return rc= memcached_purge(ptr);
     if (rc != MEMCACHED_SUCCESS && rc != MEMCACHED_STORED)
-       return MEMCACHED_FAILURE;
+      return MEMCACHED_FAILURE;
   }
 
-  error= poll(fds, 1, ptr->root->poll_timeout);
+  int timeout= ptr->root->poll_timeout;
+  if ((ptr->root->flags & MEM_NO_BLOCK) == 0)
+    timeout= -1;
+
+  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
@@ -89,8 +169,8 @@ void memcached_io_preread(memcached_st *ptr)
 }
 #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;
 
@@ -104,31 +184,26 @@ ssize_t memcached_io_read(memcached_server_st *ptr,
 
       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:
-          case EINTR: 
-            {
-              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;
             }
           }
         }
@@ -144,13 +219,14 @@ ssize_t memcached_io_read(memcached_server_st *ptr,
             it will return EGAIN if data is not immediatly available.
           */
           memcached_quit_server(ptr, 1);
-          return -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;
     }
 
@@ -176,7 +252,9 @@ ssize_t memcached_io_read(memcached_server_st *ptr,
     }
   }
 
-  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,
@@ -194,18 +272,30 @@ ssize_t memcached_io_write(memcached_server_st *ptr,
   {
     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;
@@ -216,8 +306,10 @@ ssize_t memcached_io_write(memcached_server_st *ptr,
         return -1;
 
       /* If io_flush calls memcached_purge, sent_length may be 0 */
-      if (sent_length != 0)
-        WATCHPOINT_ASSERT(sent_length == MEMCACHED_MAX_BUFFER);
+      unlikely (sent_length != 0)
+      {
+        WATCHPOINT_ASSERT(sent_length == (ssize_t)buffer_end);
+      }
     }
   }
 
@@ -229,7 +321,7 @@ ssize_t memcached_io_write(memcached_server_st *ptr,
       return -1;
   }
 
-  return original_length;
+  return (ssize_t) original_length;
 }
 
 memcached_return memcached_io_close(memcached_server_st *ptr)
@@ -244,7 +336,7 @@ memcached_return memcached_io_close(memcached_server_st *ptr)
   {
     r= shutdown(ptr->fd, SHUT_RDWR);
 
-#ifdef HAVE_DEBUG
+#ifdef DEBUG
     if (r && errno != ENOTCONN)
     {
       WATCHPOINT_NUMBER(ptr->fd);
@@ -255,7 +347,7 @@ memcached_return memcached_io_close(memcached_server_st *ptr)
   }
 
   r= close(ptr->fd);
-#ifdef HAVE_DEBUG
+#ifdef DEBUG
   if (r != 0)
     WATCHPOINT_ERRNO(errno);
 #endif
@@ -263,6 +355,56 @@ memcached_return memcached_io_close(memcached_server_st *ptr)
   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)
 {
@@ -288,11 +430,16 @@ static ssize_t io_flush(memcached_server_st *ptr,
 
   WATCHPOINT_ASSERT(ptr->fd != -1);
 
-  if (ptr->write_buffer_offset == 0)
+  // 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));
@@ -305,79 +452,73 @@ static ssize_t io_flush(memcached_server_st *ptr,
     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
-    {
-      WATCHPOINT_ASSERT(ptr->fd != -1);
-      if ((sent_length= write(ptr->fd, local_write_ptr, 
-                              write_length)) == -1)
+      case ENOBUFS:
+        continue;
+      case EAGAIN:
       {
-        ptr->cached_errno= errno;
-        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 || rc == MEMCACHED_TIMEOUT) 
-              continue;
+        memcached_return rc;
+        rc= io_wait(ptr, MEM_WRITE);
 
-            memcached_quit_server(ptr, 1);
-            return -1;
-          }
-        default:
-          memcached_quit_server(ptr, 1);
-          *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)
@@ -387,7 +528,7 @@ void memcached_io_reset(memcached_server_st *ptr)
 
 /**
  * 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. 
+ * buffer. Reset the IO channel on this server if an error occurs.
  */
 memcached_return memcached_safe_read(memcached_server_st *ptr,
                                      void *dta,
@@ -398,13 +539,13 @@ memcached_return memcached_safe_read(memcached_server_st *ptr,
 
   while (offset < size)
   {
-    ssize_t nread= memcached_io_read(ptr, data + offset, size - offset);
-    if (nread <= 0)
-    {
-      memcached_io_reset(ptr);
-      return MEMCACHED_UNKNOWN_READ_FAILURE;
-    }
-    offset+= nread;
+    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;
@@ -415,7 +556,7 @@ memcached_return memcached_io_readline(memcached_server_st *ptr,
                                        size_t size)
 {
   bool line_complete= false;
-  int total_nr= 0;
+  size_t total_nr= 0;
 
   while (!line_complete)
   {
@@ -426,8 +567,10 @@ memcached_return memcached_io_readline(memcached_server_st *ptr,
        * buffer. Call the standard read function to avoid duplicating
        * the logic.
        */
-      if (memcached_io_read(ptr, buffer_ptr, 1) != 1)
-        return MEMCACHED_UNKNOWN_READ_FAILURE;
+      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;
@@ -454,3 +597,40 @@ memcached_return memcached_io_readline(memcached_server_st *ptr,
 
   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;
+}