X-Git-Url: https://code.citadel.org/?a=blobdiff_plain;f=webcit%2Fcontext_loop.c;h=e9ea3772ac210c8bc348c62a564ce6945b1bc2b1;hb=792253218528e4327e0ddf1da78e424c9c9f08a4;hp=814f1355a6f7b142817e8d09ee3ec6243b3dd7df;hpb=82abbe960ef846f529815a0326f1b9c3266ee86a;p=citadel.git

diff --git a/webcit/context_loop.c b/webcit/context_loop.c
index 814f1355a..e9ea3772a 100644
--- a/webcit/context_loop.c
+++ b/webcit/context_loop.c
@@ -2,165 +2,393 @@
  * context_loop.c
  *
  * This is the other half of the webserver.  It handles the task of hooking
- * up HTTP requests with the session they belong to, using HTTP cookies to
+ * up HTTP requests with the sessions they belong to, using HTTP cookies to
  * keep track of things.  If the HTTP request doesn't belong to any currently
- * active session, a new session is spawned.
+ * active session, a new session is started.
+ *
+ * $Id$
  */
 
+#include <ctype.h>
 #include <stdlib.h>
+#ifdef HAVE_UNISTD_H
 #include <unistd.h>
+#endif
 #include <stdio.h>
+#ifdef HAVE_FCNTL_H
 #include <fcntl.h>
+#endif
 #include <signal.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <sys/socket.h>
+#ifdef HAVE_SYS_TIME_H
 #include <sys/time.h>
+#endif
+#ifdef HAVE_LIMITS_H
 #include <limits.h>
+#endif
 #include <netinet/in.h>
 #include <netdb.h>
 #include <string.h>
-
 #include <errno.h>
 #include <stdarg.h>
 #include <pthread.h>
+#include <signal.h>
+#include "webcit.h"
+#include "webserver.h"
 
-/*
- * We keep one of these around for each active session
- */
-struct wc_session {
-	struct wc_session *next;	/* Next session in list */
-	int session_id;			/* Session ID */
-	int inpipe[2];			/* Data from webserver to session */
-	int outpipe[2];			/* Data from session to webserver */
-	pthread_mutex_t critter;	/* Critical section uses pipes */
-	};
-
-struct wc_session *SessionList = NULL;
-
-int GenerateSessionID() {
-	return getpid();
+/* Only one thread may manipulate SessionList at a time... */
+pthread_mutex_t SessionListMutex;
+
+struct wcsession *SessionList = NULL;
+
+pthread_key_t MyConKey;                         /* TSD key for MySession() */
+
+
+void free_attachments(struct wcsession *sess) {
+	struct wc_attachment *att;
+
+	while (sess->first_attachment != NULL) {
+		att = sess->first_attachment;
+		sess->first_attachment = sess->first_attachment->next;
+		free(att->data);
+		free(att);
 	}
+}
 
 
-void gets0(int fd, char buf[]) {
+void do_housekeeping(void)
+{
+	struct wcsession *sptr, *ss, *session_to_kill;
+	int num_sessions = 0;
+	static int num_threads = MIN_WORKER_THREADS;
 
-	buf[0] = 0;
 	do {
-		buf[strlen(buf)+1] = 0;
-		read(fd, &buf[strlen(buf)], 1);
-		} while (buf[strlen(buf)-1] >= 32);
-	buf[strlen(buf)-1] = 0;
+		session_to_kill = NULL;
+		pthread_mutex_lock(&SessionListMutex);
+		num_sessions = 0;
+		for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
+			++num_sessions;
+
+			/* Kill idle sessions */
+			if ((time(NULL) - (sptr->lastreq)) >
+			   (time_t) WEBCIT_TIMEOUT) {
+				sptr->killthis = 1;
+			}
+
+			/* Remove sessions flagged for kill */
+			if (sptr->killthis) {
+
+				lprintf(3, "Destroying session %d\n",
+					sptr->wc_session);
+
+				/* remove session from linked list */
+				if (sptr == SessionList) {
+					SessionList = SessionList->next;
+				}
+				else for (ss=SessionList;ss!=NULL;ss=ss->next) {
+					if (ss->next == sptr) {
+						ss->next = ss->next->next;
+					}
+				}
+
+				session_to_kill = sptr;
+				goto BREAKOUT;
+			}
+		}
+BREAKOUT:	pthread_mutex_unlock(&SessionListMutex);
+
+		if (session_to_kill != NULL) {
+			pthread_mutex_lock(&session_to_kill->SessionMutex);
+			close(session_to_kill->serv_sock);
+			close(session_to_kill->chat_sock);
+			if (session_to_kill->preferences != NULL) {
+				free(session_to_kill->preferences);
+			}
+			free_attachments(session_to_kill);
+			pthread_mutex_unlock(&session_to_kill->SessionMutex);
+			free(session_to_kill);
+		}
+
+	} while (session_to_kill != NULL);
+
+	/*
+	 * See if we need more worker threads
+	 */
+	while ( (num_sessions > num_threads)
+	      && (num_threads <= MAX_WORKER_THREADS) ) {
+		spawn_another_worker_thread();
+		++num_threads;
+		lprintf(3, "There are %d sessions and %d threads active.\n",
+			num_sessions, num_threads);
 	}
+}
+
+
+/* 
+ * Wake up occasionally and clean house
+ */
+void housekeeping_loop(void)
+{
+	while (1) {
+		sleeeeeeeeeep(HOUSEKEEPING);
+		do_housekeeping();
+	}
+}
 
 
 /*
- * This loop gets called once for every HTTP connection made to WebCit.
+ * Generate a unique WebCit session ID (which is not the same thing as the
+ * Citadel session ID).
+ *
+ * FIXME ... ensure that session number is truly unique
+ *
  */
-void *context_loop(int *socknumptr) {
-	char req[256][256];
-	char buf[256];
-	int num_lines = 0;
+int GenerateSessionID(void)
+{
+	static int seq = (-1);
+
+	if (seq < 0) {
+		seq = (int) time(NULL);
+	}
+		
+	return ++seq;
+}
+
+
+/*
+ * Collapse multiple cookies on one line
+ */
+int req_gets(int sock, char *buf, char *hold)
+{
 	int a;
-	int f;
-	int sock;
-	int desired_session = 0;
-	char str_session[256];
-	struct wc_session *sptr;
-	struct wc_session *TheSession;
-	int ContentLength;
 
-	sock = *socknumptr;
+	if (strlen(hold) == 0) {
+		strcpy(buf, "");
+		a = client_gets(sock, buf);
+		if (a<1) return(-1);
+	} else {
+		safestrncpy(buf, hold, SIZ);
+	}
+	strcpy(hold, "");
+
+	if (!strncasecmp(buf, "Cookie: ", 8)) {
+		for (a = 0; a < strlen(buf); ++a)
+			if (buf[a] == ';') {
+				sprintf(hold, "Cookie: %s", &buf[a + 1]);
+				buf[a] = 0;
+				while (isspace(hold[8]))
+					strcpy(&hold[8], &hold[9]);
+				return(0);
+			}
+	}
+
+	return(0);
+}
+
+/*
+ * lingering_close() a`la Apache. see
+ * http://www.apache.org/docs/misc/fin_wait_2.html for rationale
+ */
+
+int lingering_close(int fd)
+{
+	char buf[SIZ];
+	int i;
+	fd_set set;
+	struct timeval tv, start;
+
+	gettimeofday(&start, NULL);
+	shutdown(fd, 1);
+	do {
+		do {
+			gettimeofday(&tv, NULL);
+			tv.tv_sec = SLEEPING - (tv.tv_sec - start.tv_sec);
+			tv.tv_usec = start.tv_usec - tv.tv_usec;
+			if (tv.tv_usec < 0) {
+				tv.tv_sec--;
+				tv.tv_usec += 1000000;
+			}
+			FD_ZERO(&set);
+			FD_SET(fd, &set);
+			i = select(fd + 1, &set, NULL, NULL, &tv);
+		} while (i == -1 && errno == EINTR);
+
+		if (i <= 0)
+			break;
+
+		i = read(fd, buf, sizeof buf);
+	} while (i != 0 && (i != -1 || errno == EINTR));
+
+	return close(fd);
+}
+
+
+
+/*
+ * Check for bogus requests coming from (for example) brain-dead
+ * Windoze boxes that are infected with the latest worm-of-the-week.
+ * If we detect one of these, bail out without bothering our Citadel
+ * server.
+ */
+int is_bogus(char *http_cmd) {
+
+	if (!strncasecmp(http_cmd, "GET /scripts/root.exe", 21)) return(1);
+	if (!strncasecmp(http_cmd, "GET /c/winnt", 12)) return(2);
+	if (!strncasecmp(http_cmd, "GET /MSADC/", 11)) return(3);
+
+	return(0);	/* probably ok */
+}
+
+
+
+/*
+ * This loop gets called once for every HTTP connection made to WebCit.  At
+ * this entry point we have an HTTP socket with a browser allegedly on the
+ * other end, but we have not yet bound to a WebCit session.
+ *
+ * The job of this function is to locate the correct session and bind to it,
+ * or create a session if necessary and bind to it, then run the WebCit
+ * transaction loop.  Afterwards, we unbind from the session.  When this
+ * function returns, the worker thread is then free to handle another
+ * transaction.
+ */
+void context_loop(int sock)
+{
+	struct httprequest *req = NULL;
+	struct httprequest *last = NULL;
+	struct httprequest *hptr;
+	char buf[SIZ], hold[SIZ];
+	int desired_session = 0;
+	int got_cookie = 0;
+	struct wcsession *TheSession, *sptr;
 
 	/*
 	 * Find out what it is that the web browser is asking for
 	 */
+	memset(hold, 0, sizeof(hold));
 	do {
-		client_gets(sock, buf);
-		if (!strncasecmp(buf, "Cookie: wc_session=", 19)) {
-			desired_session = atoi(&buf[19]);
-			}
+		if (req_gets(sock, buf, hold) < 0) return;
+
+		if (!strncasecmp(buf, "Cookie: webcit=", 15)) {
+			cookie_to_stuff(&buf[15], &desired_session,
+				NULL, NULL, NULL);
+			got_cookie = 1;
+		}
+
+		hptr = (struct httprequest *)
+			malloc(sizeof(struct httprequest));
+		if (req == NULL)
+			req = hptr;
+		else
+			last->next = hptr;
+		hptr->next = NULL;
+		last = hptr;
+
+		safestrncpy(hptr->line, buf, sizeof hptr->line);
+
+	} while (strlen(buf) > 0);
 
+	safestrncpy(buf, req->line, sizeof buf);
+	lprintf(5, "HTTP: %s\n", buf);
 
-		strcpy(&req[num_lines++][0], buf);
-		} while(strlen(buf)>0);
+	/* Check for bogus requests */
+	if (is_bogus(buf)) goto bail;
+
+	/*
+	 * If requesting a non-root page, there should already be a cookie
+	 * set.  If there isn't, the client browser has cookies turned off
+	 * (or doesn't support them) and we have to barf & bail.
+	 */
+	if (!strncasecmp(buf, "GET ", 4)) strcpy(buf, &buf[4]);
+	else if (!strncasecmp(buf, "HEAD ", 5)) strcpy(buf, &buf[5]);
+	else if (!strncasecmp(buf, "POST ", 5)) strcpy(buf, &buf[5]);
+	if (buf[1]==' ') buf[1]=0;
+
+	/*
+	 * While we're at it, gracefully handle requests for the
+	 * robots.txt and favicon.ico files.
+	 */
+	if (!strncasecmp(buf, "/robots.txt", 11)) {
+		strcpy(req->line, "GET /static/robots.txt"
+				"?force_close_session=yes HTTP/1.0");
+	}
+	else if (!strncasecmp(buf, "/favicon.ico", 12)) {
+		strcpy(req->line, "GET /static/favicon.ico");
+	}
+
+	/* These are the URL's which may be executed without a
+	 * session cookie already set.  If it's not one of these,
+	 * force the session to close because cookies are
+	 * probably disabled on the client browser.
+	 */
+	else if ( (strcmp(buf, "/"))
+		&& (strncasecmp(buf, "/listsub", 8))
+		&& (strncasecmp(buf, "/freebusy", 9))
+		&& (strncasecmp(buf, "/do_logout", 10))
+	        && (got_cookie == 0)) {
+		strcpy(req->line, "GET /static/nocookies.html"
+				"?force_close_session=yes HTTP/1.0");
+	}
 
 	/*
 	 * See if there's an existing session open with the desired ID
 	 */
 	TheSession = NULL;
 	if (desired_session != 0) {
-		for (sptr=SessionList; sptr!=NULL; sptr=sptr->next) {
-			if (sptr->session_id == desired_session) {
+		pthread_mutex_lock(&SessionListMutex);
+		for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
+			if (sptr->wc_session == desired_session) {
 				TheSession = sptr;
-				}
 			}
 		}
+		pthread_mutex_unlock(&SessionListMutex);
+	}
 
 	/*
 	 * Create a new session if we have to
 	 */
 	if (TheSession == NULL) {
-		printf("Creating a new session\n");
-		TheSession = (struct wc_session *)
-			malloc(sizeof(struct wc_session));
-		TheSession->session_id = GenerateSessionID();
-		pthread_mutex_init(&TheSession->critter, NULL);
-		pipe(TheSession->inpipe);
-		pipe(TheSession->outpipe);
+		lprintf(3, "Creating a new session\n");
+		TheSession = (struct wcsession *)
+			malloc(sizeof(struct wcsession));
+		memset(TheSession, 0, sizeof(struct wcsession));
+		TheSession->serv_sock = (-1);
+		TheSession->chat_sock = (-1);
+		TheSession->wc_session = GenerateSessionID();
+		pthread_mutex_init(&TheSession->SessionMutex, NULL);
+
+		pthread_mutex_lock(&SessionListMutex);
 		TheSession->next = SessionList;
 		SessionList = TheSession;
-		sprintf(str_session, "%d", TheSession->session_id);
-		f = fork();
-		fflush(stdout); fflush(stdin);
-		if (f==0) {
-			dup2(TheSession->inpipe[0], 0);
-			dup2(TheSession->outpipe[1], 1);
-			execlp("./webcit", "webcit", str_session, NULL);
-			printf("HTTP/1.0 404 WebCit Failure\n\n");
-			printf("Content-type: text/html\n");
-			printf("Content-length: 76\n");
-			printf("\n");
-			printf("<HTML><HEAD><TITLE>Error</TITLE></HEAD>\n");
-			printf("<BODY>execlp() failed</BODY></HTML>\n");
-			exit(0);
-			}
-		}
+		pthread_mutex_unlock(&SessionListMutex);
+	}
 
-	/* 
-	 * Send the request to the appropriate session
+	/*
+	 * A future improvement might be to check the session integrity
+	 * at this point before continuing.
 	 */
-	pthread_mutex_lock(&TheSession->critter);
-	for (a=0; a<num_lines; ++a) {
-		write(TheSession->inpipe[1], &req[a][0], strlen(&req[a][0]));
-		write(TheSession->inpipe[1], "\n", 1);
-		}
-	write(TheSession->inpipe[1], "\n", 1);
 
 	/*
-	 * ...and get the response (FIX for non-text)
+	 * Bind to the session and perform the transaction
 	 */
-	ContentLength = 0;
-	do {
-		gets0(TheSession->outpipe[0], buf);
-		write(sock, buf, strlen(buf));
-		write(sock, "\n", 1);
-		if (!strncasecmp(buf, "Content-length: ", 16))
-			ContentLength = atoi(&buf[16]);
-		} while (strlen(buf) > 0);
-
-	while(ContentLength--) {
-		read(TheSession->outpipe[0], buf, 1);
-		write(sock, buf, 1);
-		}
+	pthread_mutex_lock(&TheSession->SessionMutex);		/* bind */
+	pthread_setspecific(MyConKey, (void *)TheSession);
+	TheSession->http_sock = sock;
+	TheSession->lastreq = time(NULL);			/* log */
+	session_loop(req);				/* do transaction */
+	pthread_mutex_unlock(&TheSession->SessionMutex);	/* unbind */
 
-	pthread_mutex_unlock(&TheSession->critter);
+	/* Free the request buffer */
+bail:	while (req != NULL) {
+		hptr = req->next;
+		free(req);
+		req = hptr;
+	}
 
-	/*
-	 * Now our HTTP connection is done.  It would be relatively easy
-	 * to support HTTP/1.1 "persistent" connections by looping back to
-	 * the top of this function.  For now, we'll just exit.
+	/* Free up any session-local substitution variables which
+	 * were set during this transaction
 	 */
-	close(sock);
-	pthread_exit(NULL);
-	}
+	clear_local_substs();
+}