4 * This is the other half of the webserver. It handles the task of hooking
5 * up HTTP requests with the session they belong to, using HTTP cookies to
6 * keep track of things. If the HTTP request doesn't belong to any currently
7 * active session, a new session is spawned.
22 #include <sys/types.h>
24 #include <sys/socket.h>
25 #ifdef HAVE_SYS_TIME_H
31 #include <netinet/in.h>
39 #include "webserver.h"
41 /* Only one thread may manipulate SessionList at a time... */
42 pthread_mutex_t SessionListMutex;
44 struct wcsession *SessionList = NULL;
46 pthread_key_t MyConKey; /* TSD key for MySession() */
48 void do_housekeeping(void)
50 struct wcsession *sptr, *ss, *session_to_kill;
53 session_to_kill = NULL;
54 pthread_mutex_lock(&SessionListMutex);
55 for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
57 /* Kill idle sessions */
58 if ((time(NULL) - (sptr->lastreq)) >
59 (time_t) WEBCIT_TIMEOUT) {
63 /* Remove sessions flagged for kill */
66 /* remove session from linked list */
67 if (sptr == SessionList) {
68 SessionList = SessionList->next;
70 else for (ss=SessionList;ss!=NULL;ss=ss->next) {
71 if (ss->next == sptr) {
72 ss->next = ss->next->next;
76 session_to_kill = sptr;
80 BREAKOUT: pthread_mutex_unlock(&SessionListMutex);
82 if (session_to_kill != NULL) {
83 pthread_mutex_lock(&session_to_kill->SessionMutex);
84 close(session_to_kill->serv_sock);
85 pthread_mutex_unlock(&session_to_kill->SessionMutex);
86 free(session_to_kill);
89 } while (session_to_kill != NULL);
94 * Wake up occasionally and clean house
96 void housekeeping_loop(void)
106 * Generate a unique WebCit session ID (which is not the same thing as the
107 * Citadel session ID).
109 * FIX ... ensure that session number is truly unique
112 int GenerateSessionID(void)
114 static int seq = (-1);
117 seq = (int) time(NULL);
125 * Collapse multiple cookies on one line
127 int req_gets(int sock, char *buf, char *hold)
131 if (strlen(hold) == 0) {
132 a = client_gets(sock, buf);
139 if (!strncasecmp(buf, "Cookie: ", 8)) {
140 for (a = 0; a < strlen(buf); ++a)
142 sprintf(hold, "Cookie: %s", &buf[a + 1]);
144 while (isspace(hold[8]))
145 strcpy(&hold[8], &hold[9]);
153 * lingering_close() a`la Apache. see
154 * http://www.apache.org/docs/misc/fin_wait_2.html for rationale
157 static int lingering_close(int fd)
162 struct timeval tv, start;
164 gettimeofday(&start, NULL);
168 gettimeofday(&tv, NULL);
169 tv.tv_sec = SLEEPING - (tv.tv_sec - start.tv_sec);
170 tv.tv_usec = start.tv_usec - tv.tv_usec;
171 if (tv.tv_usec < 0) {
173 tv.tv_usec += 1000000;
177 i = select(fd + 1, &set, NULL, NULL, &tv);
178 } while (i == -1 && errno == EINTR);
183 i = read(fd, buf, sizeof buf);
184 } while (i != 0 && (i != -1 || errno == EINTR));
193 * This loop gets called once for every HTTP connection made to WebCit. At
194 * this entry point we have an HTTP socket with a browser allegedly on the
195 * other end, but we have not yet bound to a WebCit session.
197 * The job of this function is to locate the correct session and bind to it,
198 * or create a session if necessary and bind to it, then run the WebCit
199 * transaction loop. Afterwards, we unbind from the session. When this
200 * function returns, the worker thread is then free to handle another
203 void context_loop(int sock)
205 struct httprequest *req = NULL;
206 struct httprequest *last = NULL;
207 struct httprequest *hptr;
208 char buf[256], hold[256];
209 int desired_session = 0;
211 struct wcsession *TheSession, *sptr;
214 * Find out what it is that the web browser is asking for
217 if (req_gets(sock, buf, hold) < 0) return;
218 if (!strncasecmp(buf, "Cookie: webcit=", 15)) {
219 cookie_to_stuff(&buf[15], &desired_session,
224 hptr = (struct httprequest *)
225 malloc(sizeof(struct httprequest));
233 strcpy(hptr->line, buf);
235 } while (strlen(buf) > 0);
239 * If requesting a non-root page, there should already be a cookie
240 * set. If there isn't, the client browser has cookies turned off
241 * (or doesn't support them) and we have to barf & bail.
243 strcpy(buf, req->line);
244 if (!strncasecmp(buf, "GET ", 4)) strcpy(buf, &buf[4]);
245 else if (!strncasecmp(buf, "HEAD ", 5)) strcpy(buf, &buf[5]);
246 if (buf[1]==' ') buf[1]=0;
249 * While we're at it, gracefully handle requests for the
252 if (!strncasecmp(buf, "/robots.txt", 11)) {
253 strcpy(req->line, "GET /static/robots.txt HTTP/1.0");
256 /* Do the non-root-cookie check now. */
257 else if ( (strcmp(buf, "/")) && (got_cookie == 0)) {
258 strcpy(req->line, "GET /static/nocookies.html HTTP/1.0");
264 * See if there's an existing session open with the desired ID
267 if (desired_session != 0) {
268 pthread_mutex_lock(&SessionListMutex);
269 for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
270 if (sptr->wc_session == desired_session) {
274 pthread_mutex_unlock(&SessionListMutex);
278 * Create a new session if we have to
280 if (TheSession == NULL) {
281 fprintf(stderr, "Creating a new session\n");
282 TheSession = (struct wcsession *)
283 malloc(sizeof(struct wcsession));
284 memset(TheSession, 0, sizeof(struct wcsession));
285 TheSession->wc_session = GenerateSessionID();
286 pthread_mutex_init(&TheSession->SessionMutex, NULL);
288 pthread_mutex_lock(&SessionListMutex);
289 TheSession->next = SessionList;
290 SessionList = TheSession;
291 pthread_mutex_unlock(&SessionListMutex);
297 * FIX ... check session integrity here before continuing
304 * Bind to the session and perform the transaction
306 pthread_mutex_lock(&TheSession->SessionMutex); /* bind */
307 pthread_setspecific(MyConKey, (void *)TheSession);
308 TheSession->http_sock = sock;
309 TheSession->lastreq = time(NULL); /* log */
310 fprintf(stderr, "%s\n", req->line);
311 session_loop(req); /* perform the requested transaction */
312 pthread_mutex_unlock(&TheSession->SessionMutex); /* unbind */
314 /* Free the request buffer */
315 while (req != NULL) {
322 * Now our HTTP connection is done. Close the socket and exit this
323 * function, so the worker thread can handle a new HTTP connection.
325 lingering_close(sock);