src/server/iotquery.cpp

   1 #include "iotquery.h"
   2 #include <string.h>
   3 #include <sys/stat.h>
   4 #include <sys/types.h>
   5 #include <sys/file.h>
   6 #include <fcntl.h>
   7 #include <unistd.h>
   8 #include <stdlib.h>
   9 #include <errno.h>
  10 #include <netinet/in.h>
  11
  12 using namespace std;
  13
  14 const char * query_str="QUERY_STRING";
  15 const char * uri_str="REQUEST_URI";
  16 const char * method_str="REQUEST_METHOD";
  17 const char * iotcloudroot_str="IOTCLOUD_ROOT";
  18 const char * length_str="CONTENT_LENGTH";
  19
  20 IoTQuery::IoTQuery(FCGX_Request *request) :
  21         request(request),
  22         data(NULL),
  23         directory(NULL),
  24         uri(NULL),
  25         query(NULL),
  26         method(NULL),
  27         iotcloudroot(NULL),
  28         length(0),
  29         oldestentry(0),
  30         newestentry(0),
  31         requestsequencenumber(0),
  32         numqueueentries(DEFAULT_SIZE),
  33         fd(-1),
  34         reqGetSlot(false),
  35         reqPutSlot(false) {
  36 }
  37
  38 IoTQuery::~IoTQuery() {
  39         if (fd >= 0)
  40                 close(fd);
  41         if (directory)
  42                 delete directory;
  43         if (data)
  44                 delete data;
  45 }
  46
  47 bool IoTQuery::checkDirectory() {
  48         struct stat s;
  49         int err=stat(directory, &s);
  50         if (-1 == err)
  51                 return false;
  52         return S_ISDIR(s.st_mode);
  53 }
  54
  55 void IoTQuery::decodeQuery() {
  56         int len=strlen(query);
  57         char * str=new char[len+1];
  58         memcpy(str, query, len+1);
  59         char *tok_ptr=str;
  60
  61         /* Parse commands */
  62         char *command=strsep(&tok_ptr, "&");
  63         if (strncmp(command, "req=putslot", 11) == 0)
  64                 reqPutSlot = true;
  65
  66         if (strncmp(command, "req=getslot", 11) == 0)
  67                 reqGetSlot = true;
  68
  69         /* Load Sequence Number for request */
  70         char *sequencenumber_str = strsep(&tok_ptr, "&");
  71         if (sequencenumber_str != NULL &&
  72                         strncmp(sequencenumber_str, "seq=", 4) == 0) {
  73                 sequencenumber_str = strchr(sequencenumber_str, '=');
  74                 if (sequencenumber_str != NULL) {
  75                         requestsequencenumber = strtoll(sequencenumber_str + 1, NULL, 10);
  76                 }
  77         }
  78
  79         /* Update size if we get request */
  80         char * numqueueentries_str = tok_ptr;
  81         if (numqueueentries_str != NULL &&
  82                         strncmp(numqueueentries_str, "max=", 4) == 0) {
  83                 numqueueentries_str = strchr(numqueueentries_str + 1, '=');
  84                 numqueueentries = strtoll(numqueueentries_str, NULL, 10);
  85         }
  86
  87         delete str;
  88 }
  89
  90 void doWrite(int fd, char *data, long long length) {
  91         long long offset=0;
  92         do {
  93                 long long byteswritten=write(fd, &data[offset], length);
  94                 if (byteswritten > 0) {
  95                         length -= byteswritten;
  96                         offset += byteswritten;
  97                 } else {
  98                         cerr << "Bytes not written" << endl;
  99                         if (byteswritten < 0) {
 100                                 cerr << strerror(errno) << " error writing slot file" << endl;
 101                         }
 102                         return;
 103                 }
 104         } while(length != 0);
 105 }
 106
 107 bool doRead(int fd, void *buf, int numbytes) {
 108         int offset=0;
 109         char *ptr=(char *)buf;
 110         do {
 111                 int bytesread=read(fd, ptr+offset, numbytes);
 112                 if (bytesread > 0) {
 113                         offset += bytesread;
 114                         numbytes -= bytesread;
 115                 } else
 116                         return false;
 117         } while (numbytes!=0);
 118         return true;
 119 }
 120
 121 void IoTQuery::getSlot() {
 122         int numrequeststosend = (int)((newestentry-requestsequencenumber)+1);
 123         if (numrequeststosend < 0)
 124                 numrequeststosend = 0;
 125         long long numbytes = 0;
 126         int filesizes[numrequeststosend];
 127         int fdarray[numrequeststosend];
 128         int index=0;
 129         for(long long seqn = requestsequencenumber; seqn <= newestentry; seqn++, index++) {
 130                 struct stat st;
 131                 char *filename=getSlotFileName(seqn);
 132                 if (stat(filename, &st) == 0) {
 133                         fdarray[index]=open(filename, O_RDONLY);
 134                         filesizes[index]=st.st_size;
 135                         numbytes+=filesizes[index];
 136                 } else {
 137                         fdarray[index]=-1;
 138                         filesizes[index]=0;
 139                 }
 140                 delete filename;
 141         }
 142         const char header[]="getslot";
 143         long long size=sizeof(header)-1+sizeof(numrequeststosend)+4*numrequeststosend+numbytes; //header + payload + file count + sizes
 144         char * response = new char[size];
 145         long long offset=0;
 146         memcpy(response, header, sizeof(header)-1);
 147         offset+=sizeof(header)-1;
 148         int numreq=htonl(numrequeststosend);
 149         cerr << numrequeststosend << " " << numreq << endl;
 150         memcpy(response + offset, &numreq, sizeof(numreq));
 151         offset+=sizeof(numrequeststosend);
 152         for(int i=0;i<numrequeststosend;i++) {
 153                 int filesize=htonl(filesizes[i]);
 154                 memcpy(response + offset, &filesize, sizeof(filesize));
 155                 offset+=sizeof(int);
 156         }
 157
 158         //copy file data
 159         for(int i=0;i<numrequeststosend;i++) {
 160                 if (fdarray[i]>=0) {
 161                         doRead(fdarray[i], response+offset, filesizes[i]);
 162                         offset+=filesizes[i];
 163                 }
 164         }
 165
 166         //write response out
 167         sendResponse(response, size);
 168
 169         //cleanup
 170         delete response;
 171         for(int i=0;i<numrequeststosend;i++) {
 172                 if (fdarray[i] >= 0)
 173                         close(fdarray[i]);
 174         }
 175 }
 176
 177 void IoTQuery::putSlot() {
 178         if (requestsequencenumber!=(newestentry+1)) {
 179                 getSlot();
 180                 return;
 181         }
 182
 183         int numberofliveslots=(int) ((newestentry-oldestentry)+1);
 184         if (numberofliveslots >=  numqueueentries) {
 185                 //need to drop slot
 186                 removeOldestSlot();
 187         }
 188
 189         //write slot data out to file
 190         char *filename = getSlotFileName(requestsequencenumber);
 191         int slotfd = open(filename, O_CREAT|O_WRONLY, S_IRUSR| S_IWUSR);
 192         doWrite(slotfd, data, length);
 193         close(slotfd);
 194         delete filename;
 195         newestentry = requestsequencenumber; // update sequence number
 196         updateStatusFile(); // update counts
 197         char command[]="putslot";
 198         sendResponse(command, sizeof(command)-1);
 199 }
 200
 201 void IoTQuery::sendResponse(char * bytes, int len) {
 202         cout << "Accept-Ranges: bytes\r\n"
 203                          << "Content-Length: " << len << "\r\n"
 204                          << "\r\n";
 205         cout.write(bytes, len);
 206 }
 207
 208 char * IoTQuery::getSlotFileName(long long slot) {
 209         int directorylen=strlen(directory);
 210         char * filename=new char[25+directorylen];//19 digits for long number + 4 characters for SLOT + 1 character for null termination
 211         snprintf(filename, 24+directorylen+1, "%s/SLOT%lld", directory, slot);
 212         return filename;
 213 }
 214
 215 void IoTQuery::removeOldestSlot() {
 216         if (oldestentry!=0) {
 217                 char * filename=getSlotFileName(oldestentry);
 218                 unlink(filename);
 219                 delete filename;
 220         }
 221         oldestentry++;
 222 }
 223
 224 void IoTQuery::processQuery() {
 225         getQuery();
 226         getDirectory();
 227         readData();
 228
 229         if (strncmp(method, "POST", 4) != 0) {
 230                 cerr << "Not POST Request" << endl;
 231                 return;
 232         }
 233
 234         if (directory == NULL ||
 235                         !checkDirectory()) {
 236                 cerr << "Directory " << directory << " does not exist" << endl;
 237                 return;
 238         }
 239
 240         if (!openStatusFile()) {
 241                 cerr << "Failed to open status file" << endl;
 242                 return;
 243         }
 244
 245         flock(fd, LOCK_EX);
 246
 247         decodeQuery();
 248
 249         if (reqGetSlot)
 250                 getSlot();
 251         else if (reqPutSlot)
 252                 putSlot();
 253         else {
 254                 cerr << "No recognized request" << endl;
 255                 return;
 256         }
 257 }
 258
 259 void IoTQuery::readData() {
 260         if (length) {
 261                 data = new char[length+1];
 262                 memset(data, 0, length+1);
 263                 cin.read(data, length);
 264         }
 265         do {
 266                 char dummy;
 267                 cin >> dummy;
 268         } while (!cin.eof());
 269 }
 270
 271 void IoTQuery::getQuery() {
 272         uri = FCGX_GetParam(uri_str, request->envp);
 273         query = FCGX_GetParam(query_str, request->envp);
 274         method = FCGX_GetParam(method_str, request->envp);
 275         iotcloudroot = FCGX_GetParam(iotcloudroot_str, request->envp);
 276
 277         char * reqlength = FCGX_GetParam(length_str, request->envp);
 278         if (reqlength) {
 279                 length=strtoll(reqlength, NULL, 10);
 280         } else {
 281                 length=0;
 282         }
 283 }
 284
 285 void IoTQuery::getDirectory() {
 286         char * split = strchr((char *)uri, '?');
 287         if (split == NULL)
 288                 return;
 289         int split_len = (int) (split-uri);
 290         int rootdir_len = strlen(iotcloudroot);
 291         int directory_len = split_len + rootdir_len + 1;
 292         directory = new char[directory_len];
 293         memcpy(directory, iotcloudroot, rootdir_len);
 294         memcpy(directory + rootdir_len, uri, split_len);
 295         directory[directory_len-1]=0;
 296 }
 297
 298 int doread(int fd, void *ptr, size_t count, off_t offset) {
 299         do {
 300                 size_t bytesread=pread(fd, ptr, count, offset);
 301                 if (bytesread==count) {
 302                         return 1;
 303                 } else if (bytesread==0) {
 304                         return 0;
 305                 }
 306         } while(1);
 307 }
 308
 309 void IoTQuery::updateStatusFile() {
 310         pwrite(fd, &numqueueentries, sizeof(numqueueentries), OFFSET_MAX);
 311         pwrite(fd, &oldestentry, sizeof(oldestentry), OFFSET_OLD);
 312         pwrite(fd, &newestentry, sizeof(newestentry), OFFSET_NEW);
 313 }
 314
 315 bool IoTQuery::openStatusFile() {
 316         char statusfile[]="queuestatus";
 317         int len=strlen(directory);
 318
 319         char * filename=new char[len+sizeof(statusfile)+2];
 320         memcpy(filename, directory, len);
 321         filename[len]='/';
 322         memcpy(filename+len+1, statusfile, sizeof(statusfile));
 323         filename[len+sizeof(statusfile)+1]=0;
 324         fd=open(filename, O_CREAT| O_RDWR, S_IRUSR| S_IWUSR);
 325         delete filename;
 326
 327         if (fd < 0) {
 328                 cerr << strerror(errno) << " error opening statusfile" << endl;
 329                 return false;
 330         }
 331
 332         int size;
 333         int needwrite=0;
 334         if (doread(fd, &size, sizeof(size), OFFSET_MAX))
 335                 numqueueentries=size;
 336         else
 337                 needwrite=1;
 338
 339         long long entry;
 340         if (doread(fd, &entry, sizeof(entry), OFFSET_OLD))
 341                 oldestentry=entry;
 342         else
 343                 needwrite=1;
 344
 345         if (doread(fd, &entry, sizeof(entry), OFFSET_NEW))
 346                 newestentry=entry;
 347         else
 348                 needwrite=1;
 349
 350         if (needwrite)
 351                 updateStatusFile();
 352
 353         return true;
 354 }
 355
 356