git.m6w6.name Git - m6w6/libmemcached/blob - src/libmemcachedprotocol/handler.c

   1 /*
   2     +--------------------------------------------------------------------+
   3     | libmemcached - C/C++ Client Library for memcached                  |
   4     +--------------------------------------------------------------------+
   5     | Redistribution and use in source and binary forms, with or without |
   6     | modification, are permitted under the terms of the BSD license.    |
   7     | You should have received a copy of the license in a bundled file   |
   8     | named LICENSE; in case you did not receive a copy you can review   |
   9     | the terms online at: https://opensource.org/licenses/BSD-3-Clause  |
  10     +--------------------------------------------------------------------+
  11     | Copyright (c) 2006-2014 Brian Aker   https://datadifferential.com/ |
  12     | Copyright (c) 2020 Michael Wallner   <mike@php.net>                |
  13     +--------------------------------------------------------------------+
  14 */
  15
  16 #include "libmemcachedprotocol/common.h"
  17
  18 #include <stdlib.h>
  19 #include <sys/types.h>
  20 #include <errno.h>
  21 #include <stdbool.h>
  22 #include <string.h>
  23 #if HAVE_STRINGS_H
  24 #  include <strings.h>
  25 #endif
  26 #include <ctype.h>
  27 #include <stdio.h>
  28
  29 #include "p9y/socket.hpp"
  30
  31 /*
  32 ** **********************************************************************
  33 ** INTERNAL INTERFACE
  34 ** **********************************************************************
  35 */
  36
  37 /**
  38  * The default function to receive data from the client. This function
  39  * just wraps the recv function to receive from a socket.
  40  * See man -s3socket recv for more information.
  41  *
  42  * @param cookie cookie indentifying a client, not used
  43  * @param sock socket to read from
  44  * @param buf the destination buffer
  45  * @param nbytes the number of bytes to read
  46  * @return the number of bytes transferred of -1 upon error
  47  */
  48 static ssize_t default_recv(const void *cookie, memcached_socket_t sock, void *buf, size_t nbytes) {
  49   (void) cookie;
  50   return recv(sock, buf, nbytes, 0);
  51 }
  52
  53 /**
  54  * The default function to send data to the server. This function
  55  * just wraps the send function to send through a socket.
  56  * See man -s3socket send for more information.
  57  *
  58  * @param cookie cookie indentifying a client, not used
  59  * @param sock socket to send to
  60  * @param buf the source buffer
  61  * @param nbytes the number of bytes to send
  62  * @return the number of bytes transferred of -1 upon error
  63  */
  64 static ssize_t default_send(const void *cookie, memcached_socket_t fd, const void *buf,
  65                             size_t nbytes) {
  66   (void) cookie;
  67   return send(fd, buf, nbytes, MSG_NOSIGNAL);
  68 }
  69
  70 /**
  71  * Try to drain the output buffers without blocking
  72  *
  73  * @param client the client to drain
  74  * @return false if an error occured (connection should be shut down)
  75  *         true otherwise (please note that there may be more data to
  76  *              left in the buffer to send)
  77  */
  78 static bool drain_output(struct memcached_protocol_client_st *client) {
  79   if (client->is_verbose) {
  80     fprintf(stderr, "%s:%d %s mute:%d output:%s length:%d\n", __FILE__, __LINE__, __func__,
  81             (int) client->mute, client->output ? "yes" : "no",
  82             client->output ? (int) (client->output->nbytes - client->output->offset) : 0);
  83   }
  84
  85   /* Do we have pending data to send? */
  86   while (client->output) {
  87     ssize_t len =
  88         client->root->send(client, client->sock, client->output->data + client->output->offset,
  89                            client->output->nbytes - client->output->offset);
  90
  91     if (len == -1) {
  92       if (get_socket_errno() == EWOULDBLOCK) {
  93         return true;
  94       } else if (get_socket_errno() != EINTR) {
  95         client->error = get_socket_errno();
  96         return false;
  97       }
  98     } else {
  99       client->output->offset += (size_t) len;
 100       if (client->output->offset == client->output->nbytes) {
 101         /* This was the complete buffer */
 102         struct chunk_st *old = client->output;
 103         client->output = client->output->next;
 104         if (client->output == NULL) {
 105           client->output_tail = NULL;
 106         }
 107         cache_free(client->root->buffer_cache, old);
 108       }
 109     }
 110   }
 111
 112   return true;
 113 }
 114
 115 /**
 116  * Allocate an output buffer and chain it into the output list
 117  *
 118  * @param client the client that needs the buffer
 119  * @return pointer to the new chunk if the allocation succeeds, NULL otherwise
 120  */
 121 static struct chunk_st *allocate_output_chunk(struct memcached_protocol_client_st *client) {
 122   struct chunk_st *ret = cache_alloc(client->root->buffer_cache);
 123
 124   if (ret == NULL) {
 125     return NULL;
 126   }
 127
 128   ret->offset = ret->nbytes = 0;
 129   ret->next = NULL;
 130   ret->size = CHUNK_BUFFERSIZE;
 131   ret->data = (void *) (ret + 1);
 132   if (client->output == NULL) {
 133     client->output = client->output_tail = ret;
 134   } else {
 135     client->output_tail->next = ret;
 136     client->output_tail = ret;
 137   }
 138
 139   return ret;
 140 }
 141
 142 /**
 143  * Spool data into the send-buffer for a client.
 144  *
 145  * @param client the client to spool the data for
 146  * @param data the data to spool
 147  * @param length the number of bytes of data to spool
 148  * @return PROTOCOL_BINARY_RESPONSE_SUCCESS if success,
 149  *         PROTOCOL_BINARY_RESPONSE_ENOMEM if we failed to allocate memory
 150  */
 151 static protocol_binary_response_status spool_output(struct memcached_protocol_client_st *client,
 152                                                     const void *data, size_t length) {
 153   if (client->is_verbose) {
 154     fprintf(stderr, "%s:%d %s mute:%d length:%d\n", __FILE__, __LINE__, __func__,
 155             (int) client->mute, (int) length);
 156   }
 157
 158   if (client->mute) {
 159     return PROTOCOL_BINARY_RESPONSE_SUCCESS;
 160   }
 161
 162   size_t offset = 0;
 163
 164   struct chunk_st *chunk = client->output;
 165   while (offset < length) {
 166     if (chunk == NULL || (chunk->size - chunk->nbytes) == 0) {
 167       if ((chunk = allocate_output_chunk(client)) == NULL) {
 168         return PROTOCOL_BINARY_RESPONSE_ENOMEM;
 169       }
 170     }
 171
 172     size_t bulk = length - offset;
 173     if (bulk > chunk->size - chunk->nbytes) {
 174       bulk = chunk->size - chunk->nbytes;
 175     }
 176
 177     memcpy(chunk->data + chunk->nbytes, data, bulk);
 178     chunk->nbytes += bulk;
 179     offset += bulk;
 180   }
 181
 182   return PROTOCOL_BINARY_RESPONSE_SUCCESS;
 183 }
 184
 185 /**
 186  * Try to determine the protocol used on this connection.
 187  * If the first byte contains the magic byte PROTOCOL_BINARY_REQ we should
 188  * be using the binary protocol on the connection. I implemented the support
 189  * for the ASCII protocol by wrapping into the simple interface (aka v1),
 190  * so the implementors needs to provide an implementation of that interface
 191  *
 192  */
 193 static memcached_protocol_event_t determine_protocol(struct memcached_protocol_client_st *client,
 194                                                      ssize_t *length, void **endptr) {
 195   if (*client->root->input_buffer == (uint8_t) PROTOCOL_BINARY_REQ) {
 196     if (client->is_verbose) {
 197       fprintf(stderr, "%s:%d PROTOCOL: memcached_binary_protocol_process_data\n", __FILE__,
 198               __LINE__);
 199     }
 200     client->work = memcached_binary_protocol_process_data;
 201   } else if (client->root->callback->interface_version == 1) {
 202     if (client->is_verbose) {
 203       fprintf(stderr, "%s:%d PROTOCOL: memcached_ascii_protocol_process_data\n", __FILE__,
 204               __LINE__);
 205     }
 206
 207     /*
 208      * The ASCII protocol can only be used if the implementors provide
 209      * an implementation for the version 1 of the interface..
 210      *
 211      * @todo I should allow the implementors to provide an implementation
 212      *       for version 0 and 1 at the same time and set the preferred
 213      *       interface to use...
 214      */
 215     client->work = memcached_ascii_protocol_process_data;
 216   } else {
 217     if (client->is_verbose) {
 218       fprintf(stderr, "%s:%d PROTOCOL: Unsupported protocol\n", __FILE__, __LINE__);
 219     }
 220
 221     /* Let's just output a warning the way it is supposed to look like
 222      * in the ASCII protocol...
 223      */
 224     const char *err = "CLIENT_ERROR: Unsupported protocol\r\n";
 225     client->root->spool(client, err, strlen(err));
 226     client->root->drain(client);
 227
 228     return MEMCACHED_PROTOCOL_ERROR_EVENT; /* Unsupported protocol */
 229   }
 230
 231   return client->work(client, length, endptr);
 232 }
 233
 234 /*
 235 ** **********************************************************************
 236 ** * PUBLIC INTERFACE
 237 ** * See protocol_handler.h for function description
 238 ** **********************************************************************
 239 */
 240 struct memcached_protocol_st *memcached_protocol_create_instance(void) {
 241   struct memcached_protocol_st *ret = calloc(1, sizeof(*ret));
 242   if (ret) {
 243     ret->recv = default_recv;
 244     ret->send = default_send;
 245     ret->drain = drain_output;
 246     ret->spool = spool_output;
 247     ret->input_buffer_size = 1 * 1024 * 1024;
 248     ret->input_buffer = malloc(ret->input_buffer_size);
 249     if (ret->input_buffer == NULL) {
 250       free(ret);
 251       ret = NULL;
 252
 253       return NULL;
 254     }
 255
 256     ret->buffer_cache =
 257         cache_create("protocol_handler", CHUNK_BUFFERSIZE + sizeof(struct chunk_st), 0, NULL, NULL);
 258     if (ret->buffer_cache == NULL) {
 259       free(ret->input_buffer);
 260       free(ret);
 261       ret = NULL;
 262     }
 263   }
 264
 265   return ret;
 266 }
 267
 268 void memcached_protocol_destroy_instance(struct memcached_protocol_st *instance) {
 269   cache_destroy(instance->buffer_cache);
 270   free(instance->input_buffer);
 271   free(instance);
 272 }
 273
 274 struct memcached_protocol_client_st *
 275 memcached_protocol_create_client(struct memcached_protocol_st *instance, memcached_socket_t sock) {
 276   struct memcached_protocol_client_st *ret = calloc(1, sizeof(memcached_protocol_client_st));
 277   if (ret) {
 278     ret->root = instance;
 279     ret->sock = sock;
 280     ret->work = determine_protocol;
 281   }
 282
 283   return ret;
 284 }
 285
 286 void memcached_protocol_client_destroy(struct memcached_protocol_client_st *client) {
 287   free(client);
 288 }
 289
 290 void memcached_protocol_client_set_verbose(struct memcached_protocol_client_st *client, bool arg) {
 291   if (client) {
 292     client->is_verbose = arg;
 293   }
 294 }
 295
 296 memcached_protocol_event_t
 297 memcached_protocol_client_work(struct memcached_protocol_client_st *client) {
 298   /* Try to send data and read from the socket */
 299   bool more_data = true;
 300   do {
 301     ssize_t len = client->root->recv(client, client->sock,
 302                                      client->root->input_buffer + client->input_buffer_offset,
 303                                      client->root->input_buffer_size - client->input_buffer_offset);
 304
 305     if (len > 0) {
 306       /* Do we have the complete packet? */
 307       if (client->input_buffer_offset > 0) {
 308         memcpy(client->root->input_buffer, client->input_buffer, client->input_buffer_offset);
 309         len += (ssize_t) client->input_buffer_offset;
 310
 311         /* @todo use buffer-cache! */
 312         free(client->input_buffer);
 313         client->input_buffer_offset = 0;
 314       }
 315
 316       void *endptr;
 317       memcached_protocol_event_t events = client->work(client, &len, &endptr);
 318       if (events == MEMCACHED_PROTOCOL_ERROR_EVENT) {
 319         return MEMCACHED_PROTOCOL_ERROR_EVENT;
 320       }
 321
 322       if (len > 0) {
 323         /* save the data for later on */
 324         /* @todo use buffer-cache */
 325         client->input_buffer = malloc((size_t) len);
 326         if (client->input_buffer == NULL) {
 327           client->error = ENOMEM;
 328           return MEMCACHED_PROTOCOL_ERROR_EVENT;
 329         }
 330         memcpy(client->input_buffer, endptr, (size_t) len);
 331         client->input_buffer_offset = (size_t) len;
 332         more_data = false;
 333       }
 334     } else if (len == 0) {
 335       /* Connection closed */
 336       drain_output(client);
 337       return MEMCACHED_PROTOCOL_ERROR_EVENT;
 338     } else {
 339       if (get_socket_errno() != EWOULDBLOCK) {
 340         client->error = get_socket_errno();
 341         /* mark this client as terminated! */
 342         return MEMCACHED_PROTOCOL_ERROR_EVENT;
 343       }
 344       more_data = false;
 345     }
 346   } while (more_data);
 347
 348   if (!drain_output(client)) {
 349     return MEMCACHED_PROTOCOL_ERROR_EVENT;
 350   }
 351
 352   memcached_protocol_event_t ret = MEMCACHED_PROTOCOL_READ_EVENT;
 353   if (client->output) {
 354     ret |= MEMCACHED_PROTOCOL_READ_EVENT;
 355   }
 356
 357   return ret;
 358 }