* Debugged all possible ways for a session to terminate; do them cleanly.

[citadel.git] / citadel / sysdep.c

diff --git a/citadel/sysdep.c b/citadel/sysdep.c
index 7eea262a32c7fd67f4dc59b1c69799b6466a2937..f1545b7dc88f7334523f4c5df317dfd862e9bf56 100644 (file)
--- a/citadel/sysdep.c
+++ b/citadel/sysdep.c
@@ -312,7 +312,8 @@ struct CitContext *MyContext(void) {
  * Initialize a new context and place it in the list.
  */
 struct CitContext *CreateNewContext(void) {
-       struct CitContext *me;
+       struct CitContext *me, *ptr;
+       int num = 1;
 
        me = (struct CitContext *) mallok(sizeof(struct CitContext));
        if (me == NULL) {
@@ -328,8 +329,19 @@ struct CitContext *CreateNewContext(void) {
        me->state = CON_EXECUTING;
 
        begin_critical_section(S_SESSION_TABLE);
+
+       /* obtain a unique session number */
+       for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
+               if (ptr->cs_pid == num) {
+                       ++num;
+                       ptr = ContextList;
+               }
+       }
+
+       me->cs_pid = num;
        me->next = ContextList;
        ContextList = me;
+
        end_critical_section(S_SESSION_TABLE);
        return(me);
        }
@@ -367,7 +379,8 @@ void client_write(char *buf, int nbytes)
                if (retval < 1) {
                        lprintf(2, "client_write() failed: %s\n",
                                strerror(errno));
-                       CC->state = CON_DYING;
+                       CC->kill_me = 1;
+                       return;
                        }
                bytes_written = bytes_written + retval;
                }
@@ -423,7 +436,8 @@ int client_read_to(char *buf, int bytes, int timeout)
                if (rlen<1) {
                        lprintf(2, "client_read() failed: %s\n",
                                strerror(errno));
-                       CC->state = CON_DYING;
+                       CC->kill_me = 1;
+                       return(-1);
                        }
                len = len + rlen;
                }
@@ -494,7 +508,7 @@ void kill_session(int session_to_kill) {
        begin_critical_section(S_SESSION_TABLE);
        for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
                if (ptr->cs_pid == session_to_kill) {
-                       ptr->state = CON_DYING;
+                       ptr->kill_me = 1;
                        }
                }
        end_critical_section(S_SESSION_TABLE);
@@ -610,6 +624,36 @@ int convert_login(char NameToConvert[]) {
 
 
 
+/*
+ * Purge all sessions which have the 'kill_me' flag set.
+ * This function has code to prevent it from running more than once every
+ * few seconds, because running it after every single unbind would waste a lot
+ * of CPU time and keep the context list locked too much.
+ */
+void dead_session_purge(void) {
+       static time_t last_purge = 0;
+       struct CitContext *ptr, *rem;
+       
+       if ( (time(NULL) - last_purge) < 5 ) return;    /* Too soon, go away */
+
+       do {
+               rem = NULL;
+               begin_critical_section(S_SESSION_TABLE);
+               for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
+                       if ( (ptr->state == CON_IDLE) && (ptr->kill_me) ) {
+                               rem = ptr;      
+                       }
+               }
+               end_critical_section(S_SESSION_TABLE);
+
+               /* RemoveContext() enters its own S_SESSION_TABLE critical
+                * section, so we have to do it like this.
+                */     
+               if (rem != NULL) RemoveContext(rem);
+
+       } while (rem != NULL);
+}
+
 
        
 
@@ -918,12 +962,10 @@ SETUP_FD: FD_ZERO(&readfds);
                                pthread_setspecific(MyConKey, (void *)bind_me);
                                do_command_loop();
                                pthread_setspecific(MyConKey, (void *)NULL);
-                               if (bind_me->state == CON_DYING) {
-                                       cleanup(bind_me);
+                               bind_me->state = CON_IDLE;
+                               if (bind_me->kill_me == 1) {
+                                       RemoveContext(bind_me);
                                } 
-                               else {
-                                       bind_me->state = CON_IDLE;
-                               }
                                write(rescan[1], &junk, 1);
                        }
                        else {
@@ -932,7 +974,7 @@ SETUP_FD:   FD_ZERO(&readfds);
                        }
 
                }
-
+               dead_session_purge();
        }
 
        pthread_exit(NULL);