* 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 */
- };
+/* Only one thread may manipulate SessionList at a time... */
+pthread_mutex_t SessionListMutex;
-struct wc_session *SessionList = NULL;
+struct wcsession *SessionList = NULL;
-/* Only one thread may manipulate SessionList at a time... */
-pthread_mutex_t MasterCritter;
+pthread_key_t MyConKey; /* TSD key for MySession() */
+
+
+void free_attachments(struct wcsession *sess) {
+ struct wc_attachment *att;
-int GenerateSessionID() {
- return getpid();
+ 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();
}
+}
+
+
+/*
+ * 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
+ *
+ */
+int GenerateSessionID(void)
+{
+ static int seq = (-1);
+
+ if (seq < 0) {
+ seq = (int) time(NULL);
+ }
+
+ return ++seq;
+}
+
/*
* Collapse multiple cookies on one line
*/
-void req_gets(int sock, char *buf, char *hold) {
+int req_gets(int sock, char *buf, char *hold)
+{
int a;
- if (strlen(hold)==0) {
- client_gets(sock, buf);
- }
- else {
- strcpy(buf, hold);
- }
+ 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;
+ 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);
+}
/*
- * This loop gets called once for every HTTP connection made to WebCit.
+ * lingering_close() a`la Apache. see
+ * http://www.apache.org/docs/misc/fin_wait_2.html for rationale
*/
-void *context_loop(int sock) {
- char req[256][256];
- char buf[256], hold[256];
- int num_lines = 0;
- int a;
- int f;
- int desired_session = 0;
- char str_session[256];
- struct wc_session *sptr;
- struct wc_session *TheSession;
- int ContentLength;
- int CloseSession = 0;
- printf("Reading request from socket %d\n", sock);
+int lingering_close(int fd)
+{
+ char buf[SIZ];
+ int i;
+ fd_set set;
+ struct timeval tv, start;
- /*
- * Find out what it is that the web browser is asking for
- */
- ContentLength = 0;
+ gettimeofday(&start, NULL);
+ shutdown(fd, 1);
do {
- req_gets(sock, buf, hold);
- if (!strncasecmp(buf, "Cookie: wc_session=", 19)) {
- desired_session = atoi(&buf[19]);
+ 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;
}
- if (!strncasecmp(buf, "Content-length: ", 16)) {
- ContentLength = atoi(&buf[16]);
- }
- strcpy(&req[num_lines++][0], buf);
- } while(strlen(buf)>0);
+ 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;
/*
- * See if there's an existing session open with the desired ID
+ * Find out what it is that the web browser is asking for
*/
- TheSession = NULL;
- if (desired_session != 0) {
- pthread_mutex_lock(&MasterCritter);
- for (sptr=SessionList; sptr!=NULL; sptr=sptr->next) {
- if (sptr->session_id == desired_session) {
- TheSession = sptr;
- }
- }
- pthread_mutex_unlock(&MasterCritter);
+ memset(hold, 0, sizeof(hold));
+ do {
+ 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);
+
+ /* Check for bogus requests */
+ if (is_bogus(buf)) goto bail;
+
/*
- * Create a new session if we have to
+ * 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 (TheSession == NULL) {
- printf("Creating a new session\n");
- pthread_mutex_lock(&MasterCritter);
- TheSession = (struct wc_session *)
- malloc(sizeof(struct wc_session));
- TheSession->session_id = GenerateSessionID();
- pipe(TheSession->inpipe);
- pipe(TheSession->outpipe);
- pthread_mutex_init(&TheSession->critter, NULL);
- 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("Server: %s\n", SERVER);
- 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(&MasterCritter);
- }
+ 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;
/*
- * Grab a lock on the session, so other threads don't try to access
- * the pipes at the same time.
+ * While we're at it, gracefully handle requests for the
+ * robots.txt and favicon.ico files.
*/
- printf("Locking session %d...\n", TheSession->session_id);
- pthread_mutex_lock(&TheSession->critter);
- printf(" ...got lock\n");
+ 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");
+ }
- /*
- * Send the request to the appropriate session...
+ /* 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.
*/
- printf(" Writing %d lines of command\n", num_lines);
- printf("%s\n", &req[0][0]);
- for (a=0; a<num_lines; ++a) {
- write(TheSession->inpipe[1], &req[a][0], strlen(&req[a][0]));
- write(TheSession->inpipe[1], "\n", 1);
- }
- printf(" Writing %d bytes of content\n", ContentLength);
- while (ContentLength--) {
- read(sock, buf, 1);
- write(TheSession->inpipe[1], buf, 1);
- }
+ 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");
+ }
/*
- * ...and get the response.
+ * See if there's an existing session open with the desired ID
*/
- printf(" Reading response\n");
- 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]);
- if (!strcasecmp(buf, "X-WebCit-Session: close")) {
- CloseSession = 1;
+ TheSession = NULL;
+ if (desired_session != 0) {
+ pthread_mutex_lock(&SessionListMutex);
+ for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
+ if (sptr->wc_session == desired_session) {
+ TheSession = sptr;
}
- } while (strlen(buf) > 0);
-
- printf(" Reading %d bytes of content\n");
- while(ContentLength--) {
- read(TheSession->outpipe[0], buf, 1);
- write(sock, buf, 1);
}
+ pthread_mutex_unlock(&SessionListMutex);
+ }
/*
- * 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 close.
+ * Create a new session if we have to
*/
- printf(" Closing socket\n");
- close(sock);
+ if (TheSession == NULL) {
+ 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;
+ pthread_mutex_unlock(&SessionListMutex);
+ }
/*
- * Let go of the lock
+ * A future improvement might be to check the session integrity
+ * at this point before continuing.
*/
- printf("Unlocking.\n");
- pthread_mutex_unlock(&TheSession->critter);
-
-
/*
- * If the last response included a "close session" directive,
- * remove the context now.
+ * Bind to the session and perform the transaction
*/
- if (CloseSession) {
- printf("Removing session.\n");
- pthread_mutex_lock(&MasterCritter);
-
- if (SessionList==TheSession) {
- SessionList = SessionList->next;
- }
- else {
- for (sptr=SessionList; sptr!=NULL; sptr=sptr->next) {
- if (sptr->next == TheSession) {
- sptr->next = TheSession->next;
- }
- }
- }
-
- free(TheSession);
-
- pthread_mutex_unlock(&MasterCritter);
- }
-
+ 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 */
+ /* Free the request buffer */
+bail: while (req != NULL) {
+ hptr = req->next;
+ free(req);
+ req = hptr;
+ }
- /*
- * The thread handling this HTTP connection is now finished.
+ /* Free up any session-local substitution variables which
+ * were set during this transaction
*/
- pthread_exit(NULL);
- }
+ clear_local_substs();
+}
projects / citadel.git / blobdiff