Replace all occurrences of `strcpy' with `sstrncpy'.
[collectd.git] / src / email.c
index c1e139e..b718cf5 100644 (file)
@@ -1,11 +1,10 @@
 /**
  * collectd - src/email.c
- * Copyright (C) 2006  Sebastian Harl
+ * Copyright (C) 2006,2007  Sebastian Harl
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the
- * Free Software Foundation; either version 2 of the License, or (at your
- * option) any later version.
+ * Free Software Foundation; only version 2 of the License is applicable.
  *
  * This program is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
 
 #include "configfile.h"
 
+#include <stddef.h>
+
 #if HAVE_LIBPTHREAD
 # include <pthread.h>
-# define EMAIL_HAVE_READ 1
-#else
-# define EMAIL_HAVE_READ 0
 #endif
 
-#if HAVE_SYS_SELECT_H
-#      include <sys/select.h>
-#endif /* HAVE_SYS_SELECT_H */
-
-#if HAVE_SYS_SOCKET_H
-#      include <sys/socket.h>
-#endif /* HAVE_SYS_SOCKET_H */
-
-/* *sigh* glibc does not define UNIX_PATH_MAX in sys/un.h ... */
-#if HAVE_LINUX_UN_H
-#      include <linux/un.h>
-#elif HAVE_SYS_UN_H
-#      include <sys/un.h>
-#endif /* HAVE_LINUX_UN_H | HAVE_SYS_UN_H */
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/select.h>
 
 /* some systems (e.g. Darwin) seem to not define UNIX_PATH_MAX at all */
 #ifndef UNIX_PATH_MAX
 /* 256 bytes ought to be enough for anybody ;-) */
 #define BUFSIZE 256
 
-#ifndef COLLECTD_SOCKET_PREFIX
-# define COLLECTD_SOCKET_PREFIX "/tmp/.collectd-"
-#endif /* COLLECTD_SOCKET_PREFIX */
-
-#define SOCK_PATH COLLECTD_SOCKET_PREFIX"email"
+#define SOCK_PATH LOCALSTATEDIR"/run/"PACKAGE_NAME"-email"
 #define MAX_CONNS 5
 #define MAX_CONNS_LIMIT 16384
 
+#define log_err(...) ERROR (MODULE_NAME": "__VA_ARGS__)
+#define log_warn(...) WARNING (MODULE_NAME": "__VA_ARGS__)
+
 /*
  * Private data structures
  */
-#if EMAIL_HAVE_READ
 /* linked list of email and check types */
 typedef struct type {
        char        *name;
@@ -100,41 +85,47 @@ typedef struct {
        type_t *tail;
 } type_list_t;
 
-/* linked list of collector thread control information */
+/* collector thread control information */
 typedef struct collector {
        pthread_t thread;
 
+       /* socket descriptor of the current/last connection */
+       int socket;
+} collector_t;
+
+/* linked list of pending connections */
+typedef struct conn {
        /* socket to read data from */
        int socket;
 
        /* buffer to read data to */
-       char buffer[BUFSIZE];
-       int  idx; /* current position in buffer */
+       char *buffer;
+       int  idx; /* current write position in buffer */
+       int  length; /* length of the current line, i.e. index of '\0' */
 
-       struct collector *next;
-} collector_t;
+       struct conn *next;
+} conn_t;
 
 typedef struct {
-       collector_t *head;
-       collector_t *tail;
-} collector_list_t;
-#endif /* EMAIL_HAVE_READ */
+       conn_t *head;
+       conn_t *tail;
+} conn_list_t;
 
 /*
  * Private variables
  */
-#if EMAIL_HAVE_READ
 /* valid configuration file keys */
-static char *config_keys[] =
+static const char *config_keys[] =
 {
+       "SocketFile",
        "SocketGroup",
        "SocketPerms",
-       "MaxConns",
-       NULL
+       "MaxConns"
 };
-static int config_keys_num = 3;
+static int config_keys_num = STATIC_ARRAY_SIZE (config_keys);
 
 /* socket configuration */
+static char *sock_file  = SOCK_PATH;
 static char *sock_group = COLLECTD_GRP_NAME;
 static int  sock_perms  = S_IRWXU | S_IRWXG;
 static int  max_conns   = MAX_CONNS;
@@ -143,19 +134,24 @@ static int  max_conns   = MAX_CONNS;
 static int disabled = 0;
 
 /* thread managing "client" connections */
-static pthread_t connector;
-static int connector_socket;
+static pthread_t connector = (pthread_t) 0;
+static int connector_socket = -1;
+
+/* tell the collector threads that a new connection is available */
+static pthread_cond_t conn_available = PTHREAD_COND_INITIALIZER;
+
+/* connections that are waiting to be processed */
+static pthread_mutex_t conns_mutex = PTHREAD_MUTEX_INITIALIZER;
+static conn_list_t conns;
 
 /* tell the connector thread that a collector is available */
 static pthread_cond_t collector_available = PTHREAD_COND_INITIALIZER;
 
-/* collector threads that are in use */
-static pthread_mutex_t active_mutex = PTHREAD_MUTEX_INITIALIZER;
-static collector_list_t active;
+/* collector threads */
+static collector_t **collectors = NULL;
 
-/* collector threads that are available for use */
 static pthread_mutex_t available_mutex = PTHREAD_MUTEX_INITIALIZER;
-static collector_list_t available;
+static int available_collectors;
 
 static pthread_mutex_t count_mutex = PTHREAD_MUTEX_INITIALIZER;
 static type_list_t count;
@@ -169,44 +165,16 @@ static int score_count;
 
 static pthread_mutex_t check_mutex = PTHREAD_MUTEX_INITIALIZER;
 static type_list_t check;
-#endif /* EMAIL_HAVE_READ */
-
-#define COUNT_FILE "email/email-%s.rrd"
-static char *count_ds_def[] =
-{
-       "DS:count:GAUGE:"COLLECTD_HEARTBEAT":0:U",
-       NULL
-};
-static int count_ds_num = 1;
-
-#define SIZE_FILE  "email/email_size-%s.rrd"
-static char *size_ds_def[] =
-{
-       "DS:size:GAUGE:"COLLECTD_HEARTBEAT":0:U",
-       NULL
-};
-static int size_ds_num = 1;
-
-#define SCORE_FILE "email/spam_score.rrd"
-static char *score_ds_def[] =
-{
-       "DS:score:GAUGE:"COLLECTD_HEARTBEAT":U:U",
-       NULL
-};
-static int score_ds_num = 1;
-
-#define CHECK_FILE "email/spam_check-%s.rrd"
-static char *check_ds_def[] =
-{
-       "DS:hits:GAUGE:"COLLECTD_HEARTBEAT":0:U",
-       NULL
-};
-static int check_ds_num = 1;
 
-#if EMAIL_HAVE_READ
-static int email_config (char *key, char *value)
+/*
+ * Private functions
+ */
+static int email_config (const char *key, const char *value)
 {
-       if (0 == strcasecmp (key, "SocketGroup")) {
+       if (0 == strcasecmp (key, "SocketFile")) {
+               sock_file = sstrdup (value);
+       }
+       else if (0 == strcasecmp (key, "SocketGroup")) {
                sock_group = sstrdup (value);
        }
        else if (0 == strcasecmp (key, "SocketPerms")) {
@@ -275,7 +243,7 @@ static void type_list_incr (type_list_t *list, char *name, int incr)
 
 /* Read a single character from the socket. If an error occurs or end-of-file
  * is reached return '\0'. */
-char read_char (collector_t *src)
+static char read_char (conn_t *src)
 {
        char ret = '\0';
 
@@ -285,7 +253,9 @@ char read_char (collector_t *src)
        FD_SET (src->socket, &fdset);
 
        if (-1 == select (src->socket + 1, &fdset, NULL, NULL, NULL)) {
-               syslog (LOG_ERR, "select() failed: %s", strerror (errno));
+               char errbuf[1024];
+               log_err ("select() failed: %s",
+                               sstrerror (errno, errbuf, sizeof (errbuf)));
                return '\0';
        }
 
@@ -297,7 +267,9 @@ char read_char (collector_t *src)
                errno = 0;
                if (0 > (len = read (src->socket, (void *)&ret, 1))) {
                        if (EINTR != errno) {
-                               syslog (LOG_ERR, "read() failed: %s", strerror (errno));
+                               char errbuf[1024];
+                               log_err ("read() failed: %s",
+                                               sstrerror (errno, errbuf, sizeof (errbuf)));
                                return '\0';
                        }
                }
@@ -306,13 +278,12 @@ char read_char (collector_t *src)
                        return '\0';
        } while (EINTR == errno);
        return ret;
-} /* char read_char (collector_t *) */
+} /* static char read_char (conn_t *) */
 
 /* Read a single line (terminated by '\n') from the the socket.
  *
  * The return value is zero terminated and does not contain any newline
- * characters. In case that no complete line is available (non-blocking mode
- * should be enabled) an empty string is returned.
+ * characters.
  *
  * If an error occurs or end-of-file is reached return NULL.
  *
@@ -320,12 +291,18 @@ char read_char (collector_t *src)
  * characters of the input stream, the line will will be ignored! By
  * definition we should not get any longer input lines, thus this is
  * acceptable in this case ;-) */
-char *read_line (collector_t *src)
+static char *read_line (conn_t *src)
 {
-       int  i = 0;
-       char *ret;
+       int i = 0;
+
+       assert ((BUFSIZE >= src->idx) && (src->idx >= 0));
+       assert ((src->idx > src->length) || (src->length == 0));
 
-       assert (BUFSIZE > src->idx);
+       if (src->length > 0) { /* remove old line */
+               src->idx -= (src->length + 1);
+               memmove (src->buffer, src->buffer + src->length + 1, src->idx);
+               src->length = 0;
+       }
 
        for (i = 0; i < src->idx; ++i) {
                if ('\n' == src->buffer[i])
@@ -334,14 +311,16 @@ char *read_line (collector_t *src)
 
        if (i == src->idx) {
                fd_set fdset;
-       
+
                ssize_t len = 0;
 
                FD_ZERO (&fdset);
                FD_SET (src->socket, &fdset);
 
                if (-1 == select (src->socket + 1, &fdset, NULL, NULL, NULL)) {
-                       syslog (LOG_ERR, "select() failed: %s", strerror (errno));
+                       char errbuf[1024];
+                       log_err ("select() failed: %s",
+                                       sstrerror (errno, errbuf, sizeof (errbuf)));
                        return NULL;
                }
 
@@ -350,10 +329,12 @@ char *read_line (collector_t *src)
                do {
                        errno = 0;
                        if (0 > (len = read (src->socket,
-                                                       (void *)(&(src->buffer[0]) + src->idx),
+                                                       (void *)(src->buffer + src->idx),
                                                        BUFSIZE - src->idx))) {
                                if (EINTR != errno) {
-                                       syslog (LOG_ERR, "read() failed: %s", strerror (errno));
+                                       char errbuf[1024];
+                                       log_err ("read() failed: %s",
+                                                       sstrerror (errno, errbuf, sizeof (errbuf)));
                                        return NULL;
                                }
                        }
@@ -370,9 +351,7 @@ char *read_line (collector_t *src)
                }
 
                if (i == src->idx) {
-                       ret = (char *)smalloc (1);
-
-                       ret[0] = '\0';
+                       src->length = 0;
 
                        if (BUFSIZE == src->idx) { /* no space left in buffer */
                                while ('\n' != read_char (src))
@@ -380,157 +359,141 @@ char *read_line (collector_t *src)
 
                                src->idx = 0;
                        }
-                       return ret;
+                       return read_line (src);
                }
        }
 
-       ret = (char *)smalloc (i + 1);
-       memcpy (ret, &(src->buffer[0]), i + 1);
-       ret[i] = '\0';
+       src->buffer[i] = '\0';
+       src->length    = i;
 
-       src->idx -= (i + 1);
-
-       if (0 == src->idx)
-               src->buffer[0] = '\0';
-       else
-               memmove (&(src->buffer[0]), &(src->buffer[i + 1]), src->idx);
-       return ret;
-} /* char *read_line (collector_t *) */
+       return src->buffer;
+} /* static char *read_line (conn_t *) */
 
 static void *collect (void *arg)
 {
        collector_t *this = (collector_t *)arg;
-       
-       int loop = 1;
 
-       { /* put the socket in non-blocking mode */
-               int flags = 0;
+       char *buffer = (char *)smalloc (BUFSIZE);
 
-               errno = 0;
-               if (-1 == fcntl (this->socket, F_GETFL, &flags)) {
-                       syslog (LOG_ERR, "fcntl() failed: %s", strerror (errno));
-                       loop = 0;
-               }
+       while (1) {
+               int loop = 1;
 
-               errno = 0;
-               if (-1 == fcntl (this->socket, F_SETFL, flags | O_NONBLOCK)) {
-                       syslog (LOG_ERR, "fcntl() failed: %s", strerror (errno));
-                       loop = 0;
-               }
-       }
+               conn_t *connection;
 
-       while (loop) {
-               char *line = read_line (this);
+               pthread_mutex_lock (&conns_mutex);
 
-               if (NULL == line) {
-                       loop = 0;
-                       break;
+               while (NULL == conns.head) {
+                       pthread_cond_wait (&conn_available, &conns_mutex);
                }
 
-               if ('\0' == line[0]) {
-                       free (line);
-                       continue;
-               }
+               connection = conns.head;
+               conns.head = conns.head->next;
 
-               if (':' != line[1]) {
-                       syslog (LOG_ERR, "email: syntax error in line '%s'", line);
-                       free (line);
-                       continue;
+               if (NULL == conns.head) {
+                       conns.tail = NULL;
                }
 
-               if ('e' == line[0]) { /* e:<type>:<bytes> */
-                       char *ptr  = NULL;
-                       char *type = strtok_r (line + 2, ":", &ptr);
-                       char *tmp  = strtok_r (NULL, ":", &ptr);
-                       int  bytes = 0;
+               this->socket = connection->socket;
 
-                       if (NULL == tmp) {
-                               syslog (LOG_ERR, "email: syntax error in line '%s'", line);
-                               free (line);
-                               continue;
-                       }
+               pthread_mutex_unlock (&conns_mutex);
 
-                       bytes = atoi (tmp);
+               connection->buffer = buffer;
+               connection->idx    = 0;
+               connection->length = 0;
 
-                       pthread_mutex_lock (&count_mutex);
-                       type_list_incr (&count, type, 1);
-                       pthread_mutex_unlock (&count_mutex);
+               { /* put the socket in non-blocking mode */
+                       int flags = 0;
 
-                       pthread_mutex_lock (&size_mutex);
-                       type_list_incr (&size, type, bytes);
-                       pthread_mutex_unlock (&size_mutex);
-               }
-               else if ('s' == line[0]) { /* s:<value> */
-                       pthread_mutex_lock (&score_mutex);
-                       score = (score * (double)score_count + atof (line + 2))
-                                       / (double)(score_count + 1);
-                       ++score_count;
-                       pthread_mutex_unlock (&score_mutex);
-               }
-               else if ('c' == line[0]) { /* c:<type1>[,<type2>,...] */
-                       char *ptr  = NULL;
-                       char *type = strtok_r (line + 2, ",", &ptr);
-
-                       do {
-                               pthread_mutex_lock (&check_mutex);
-                               type_list_incr (&check, type, 1);
-                               pthread_mutex_unlock (&check_mutex);
-                       } while (NULL != (type = strtok_r (NULL, ",", &ptr)));
-               }
-               else {
-                       syslog (LOG_ERR, "email: unknown type '%c'", line[0]);
+                       errno = 0;
+                       if (-1 == fcntl (connection->socket, F_GETFL, &flags)) {
+                               char errbuf[1024];
+                               log_err ("fcntl() failed: %s",
+                                               sstrerror (errno, errbuf, sizeof (errbuf)));
+                               loop = 0;
+                       }
+
+                       errno = 0;
+                       if (-1 == fcntl (connection->socket, F_SETFL, flags | O_NONBLOCK)) {
+                               char errbuf[1024];
+                               log_err ("fcntl() failed: %s",
+                                               sstrerror (errno, errbuf, sizeof (errbuf)));
+                               loop = 0;
+                       }
                }
 
-               free (line);
-       }
+               while (loop) {
+                       char *line = read_line (connection);
 
-       /* put this thread back into the available list */
-       pthread_mutex_lock (&active_mutex);
-       {
-               collector_t *last;
-               collector_t *ptr;
+                       if (NULL == line) {
+                               loop = 0;
+                               break;
+                       }
 
-               last = NULL;
+                       if (':' != line[1]) {
+                               log_err ("syntax error in line '%s'", line);
+                               continue;
+                       }
 
-               for (ptr = active.head; NULL != ptr; last = ptr, ptr = ptr->next) {
-                       if (0 != pthread_equal (ptr->thread, this->thread))
-                               break;
-               }
+                       if ('e' == line[0]) { /* e:<type>:<bytes> */
+                               char *ptr  = NULL;
+                               char *type = strtok_r (line + 2, ":", &ptr);
+                               char *tmp  = strtok_r (NULL, ":", &ptr);
+                               int  bytes = 0;
 
-               /* the current thread _has_ to be in the active list */
-               assert (NULL != ptr);
+                               if (NULL == tmp) {
+                                       log_err ("syntax error in line '%s'", line);
+                                       continue;
+                               }
 
-               if (NULL == last) {
-                       active.head = ptr->next;
-               }
-               else {
-                       last->next = ptr->next;
+                               bytes = atoi (tmp);
+
+                               pthread_mutex_lock (&count_mutex);
+                               type_list_incr (&count, type, 1);
+                               pthread_mutex_unlock (&count_mutex);
 
-                       if (NULL == last->next) {
-                               active.tail = last;
+                               if (bytes > 0) {
+                                       pthread_mutex_lock (&size_mutex);
+                                       type_list_incr (&size, type, bytes);
+                                       pthread_mutex_unlock (&size_mutex);
+                               }
                        }
-               }
-       }
-       pthread_mutex_unlock (&active_mutex);
+                       else if ('s' == line[0]) { /* s:<value> */
+                               pthread_mutex_lock (&score_mutex);
+                               score = (score * (double)score_count + atof (line + 2))
+                                               / (double)(score_count + 1);
+                               ++score_count;
+                               pthread_mutex_unlock (&score_mutex);
+                       }
+                       else if ('c' == line[0]) { /* c:<type1>[,<type2>,...] */
+                               char *ptr  = NULL;
+                               char *type = strtok_r (line + 2, ",", &ptr);
+
+                               do {
+                                       pthread_mutex_lock (&check_mutex);
+                                       type_list_incr (&check, type, 1);
+                                       pthread_mutex_unlock (&check_mutex);
+                               } while (NULL != (type = strtok_r (NULL, ",", &ptr)));
+                       }
+                       else {
+                               log_err ("unknown type '%c'", line[0]);
+                       }
+               } /* while (loop) */
 
-       this->next = NULL;
+               close (connection->socket);
+               free (connection);
 
-       pthread_mutex_lock (&available_mutex);
+               this->socket = -1;
 
-       if (NULL == available.head) {
-               available.head = this;
-               available.tail = this;
-       }
-       else {
-               available.tail->next = this;
-               available.tail = this;
-       }
+               pthread_mutex_lock (&available_mutex);
+               ++available_collectors;
+               pthread_mutex_unlock (&available_mutex);
 
-       pthread_mutex_unlock (&available_mutex);
+               pthread_cond_signal (&collector_available);
+       } /* while (1) */
 
-       pthread_cond_signal (&collector_available);
+       free (buffer);
        pthread_exit ((void *)0);
-} /* void *collect (void *) */
+} /* static void *collect (void *) */
 
 static void *open_connection (void *arg)
 {
@@ -539,14 +502,16 @@ static void *open_connection (void *arg)
        /* create UNIX socket */
        errno = 0;
        if (-1 == (connector_socket = socket (PF_UNIX, SOCK_STREAM, 0))) {
+               char errbuf[1024];
                disabled = 1;
-               syslog (LOG_ERR, "socket() failed: %s", strerror (errno));
+               log_err ("socket() failed: %s",
+                               sstrerror (errno, errbuf, sizeof (errbuf)));
                pthread_exit ((void *)1);
        }
 
        addr.sun_family = AF_UNIX;
 
-       strncpy (addr.sun_path, SOCK_PATH, (size_t)(UNIX_PATH_MAX - 1));
+       strncpy (addr.sun_path, sock_file, (size_t)(UNIX_PATH_MAX - 1));
        addr.sun_path[UNIX_PATH_MAX - 1] = '\0';
        unlink (addr.sun_path);
 
@@ -554,327 +519,348 @@ static void *open_connection (void *arg)
        if (-1 == bind (connector_socket, (struct sockaddr *)&addr,
                                offsetof (struct sockaddr_un, sun_path)
                                        + strlen(addr.sun_path))) {
+               char errbuf[1024];
                disabled = 1;
-               syslog (LOG_ERR, "bind() failed: %s", strerror (errno));
+               connector_socket = -1; /* TODO: close? */
+               log_err ("bind() failed: %s",
+                               sstrerror (errno, errbuf, sizeof (errbuf)));
                pthread_exit ((void *)1);
        }
 
        errno = 0;
        if (-1 == listen (connector_socket, 5)) {
+               char errbuf[1024];
                disabled = 1;
-               syslog (LOG_ERR, "listen() failed: %s", strerror (errno));
+               connector_socket = -1; /* TODO: close? */
+               log_err ("listen() failed: %s",
+                               sstrerror (errno, errbuf, sizeof (errbuf)));
                pthread_exit ((void *)1);
        }
 
-       if ((uid_t)0 == geteuid ()) {
+       if ((uid_t) 0 == geteuid ())
+       {
+               struct group sg;
                struct group *grp;
-
-               errno = 0;
-               if (NULL != (grp = getgrnam (sock_group))) {
-                       errno = 0;
-                       if (0 != chown (SOCK_PATH, (uid_t)-1, grp->gr_gid)) {
-                               syslog (LOG_WARNING, "chown() failed: %s", strerror (errno));
-                       }
+               char grbuf[2048];
+               int status;
+
+               grp = NULL;
+               status = getgrnam_r (sock_group, &sg, grbuf, sizeof (grbuf), &grp);
+               if (status != 0)
+               {
+                       char errbuf[1024];
+                       log_warn ("getgrnam_r (%s) failed: %s", sock_group,
+                                       sstrerror (errno, errbuf, sizeof (errbuf)));
                }
-               else {
-                       syslog (LOG_WARNING, "getgrnam() failed: %s", strerror (errno));
+               else if (grp == NULL)
+               {
+                       log_warn ("No such group: `%s'", sock_group);
+               }
+               else
+               {
+                       status = chown (sock_file, (uid_t) -1, grp->gr_gid);
+                       if (status != 0)
+                       {
+                               char errbuf[1024];
+                               log_warn ("chown (%s, -1, %i) failed: %s",
+                                               sock_file, (int) grp->gr_gid,
+                                               sstrerror (errno, errbuf, sizeof (errbuf)));
+                       }
                }
        }
-       else {
-               syslog (LOG_WARNING, "not running as root");
+       else /* geteuid != 0 */
+       {
+               log_warn ("not running as root");
        }
 
        errno = 0;
-       if (0 != chmod (SOCK_PATH, sock_perms)) {
-               syslog (LOG_WARNING, "chmod() failed: %s", strerror (errno));
+       if (0 != chmod (sock_file, sock_perms)) {
+               char errbuf[1024];
+               log_warn ("chmod() failed: %s",
+                               sstrerror (errno, errbuf, sizeof (errbuf)));
        }
 
-       { /* initialize queue of available threads */
-               int i = 0;
+       { /* initialize collector threads */
+               int i   = 0;
+               int err = 0;
+
+               pthread_attr_t ptattr;
+
+               conns.head = NULL;
+               conns.tail = NULL;
 
-               collector_t *last;
+               pthread_attr_init (&ptattr);
+               pthread_attr_setdetachstate (&ptattr, PTHREAD_CREATE_DETACHED);
 
-               active.head = NULL;
-               active.tail = NULL;
+               available_collectors = max_conns;
 
-               available.head = (collector_t *)smalloc (sizeof (collector_t));
-               available.tail = available.head;
-               available.tail->next = NULL;
+               collectors =
+                       (collector_t **)smalloc (max_conns * sizeof (collector_t *));
 
-               last = available.head;
+               for (i = 0; i < max_conns; ++i) {
+                       collectors[i] = (collector_t *)smalloc (sizeof (collector_t));
+                       collectors[i]->socket = -1;
 
-               for (i = 1; i < max_conns; ++i) {
-                       last->next = (collector_t *)smalloc (sizeof (collector_t));
-                       last = last->next;
-                       available.tail = last;
-                       available.tail->next = NULL;
+                       if (0 != (err = pthread_create (&collectors[i]->thread, &ptattr,
+                                                       collect, collectors[i]))) {
+                               char errbuf[1024];
+                               log_err ("pthread_create() failed: %s",
+                                               sstrerror (errno, errbuf, sizeof (errbuf)));
+                               collectors[i]->thread = (pthread_t) 0;
+                       }
                }
+
+               pthread_attr_destroy (&ptattr);
        }
 
        while (1) {
                int remote = 0;
-               int err    = 0;
 
-               collector_t *collector;
-
-               pthread_attr_t ptattr;
+               conn_t *connection;
 
                pthread_mutex_lock (&available_mutex);
-               while (NULL == available.head) {
+
+               while (0 == available_collectors) {
                        pthread_cond_wait (&collector_available, &available_mutex);
                }
+
+               --available_collectors;
+
                pthread_mutex_unlock (&available_mutex);
 
                do {
                        errno = 0;
                        if (-1 == (remote = accept (connector_socket, NULL, NULL))) {
                                if (EINTR != errno) {
+                                       char errbuf[1024];
                                        disabled = 1;
-                                       syslog (LOG_ERR, "accept() failed: %s", strerror (errno));
+                                       connector_socket = -1; /* TODO: close? */
+                                       log_err ("accept() failed: %s",
+                                                       sstrerror (errno, errbuf, sizeof (errbuf)));
                                        pthread_exit ((void *)1);
                                }
                        }
                } while (EINTR == errno);
 
-               /* assign connection to next available thread */
-               pthread_mutex_lock (&available_mutex);
-
-               collector = available.head;
-               collector->socket = remote;
-
-               if (available.head == available.tail) {
-                       available.head = NULL;
-                       available.tail = NULL;
-               }
-               else {
-                       available.head = available.head->next;
-               }
-
-               pthread_mutex_unlock (&available_mutex);
-
-               collector->idx  = 0;
-               collector->next = NULL;
-
-               pthread_attr_init (&ptattr);
-               pthread_attr_setdetachstate (&ptattr, PTHREAD_CREATE_DETACHED);
+               connection = (conn_t *)smalloc (sizeof (conn_t));
 
-               if (0 == (err = pthread_create (&collector->thread, &ptattr, collect,
-                               (void *)collector))) {
-                       pthread_mutex_lock (&active_mutex);
+               connection->socket = remote;
+               connection->next   = NULL;
 
-                       if (NULL == active.head) {
-                               active.head = collector;
-                               active.tail = collector;
-                       }
-                       else {
-                               active.tail->next = collector;
-                               active.tail = collector;
-                       }
+               pthread_mutex_lock (&conns_mutex);
 
-                       pthread_mutex_unlock (&active_mutex);
+               if (NULL == conns.head) {
+                       conns.head = connection;
+                       conns.tail = connection;
                }
                else {
-                       pthread_mutex_lock (&available_mutex);
-
-                       if (NULL == available.head) {
-                               available.head = collector;
-                               available.tail = collector;
-                       }
-                       else {
-                               available.tail->next = collector;
-                               available.tail = collector;
-                       }
-
-                       pthread_mutex_unlock (&available_mutex);
-
-                       close (remote);
-                       syslog (LOG_ERR, "pthread_create() failed: %s", strerror (err));
+                       conns.tail->next = connection;
+                       conns.tail = conns.tail->next;
                }
 
-               pthread_attr_destroy (&ptattr);
+               pthread_mutex_unlock (&conns_mutex);
+
+               pthread_cond_signal (&conn_available);
        }
        pthread_exit ((void *)0);
-} /* void *open_connection (void *) */
-#endif /* EMAIL_HAVE_READ */
+} /* static void *open_connection (void *) */
 
-static void email_init (void)
+static int email_init (void)
 {
-#if EMAIL_HAVE_READ
        int err = 0;
 
        if (0 != (err = pthread_create (&connector, NULL,
                                open_connection, NULL))) {
+               char errbuf[1024];
                disabled = 1;
-               syslog (LOG_ERR, "pthread_create() failed: %s", strerror (err));
-               return;
+               log_err ("pthread_create() failed: %s",
+                               sstrerror (errno, errbuf, sizeof (errbuf)));
+               return (-1);
        }
-#endif /* EMAIL_HAVE_READ */
-       return;
-} /* static void email_init (void) */
-
-#if EMAIL_HAVE_READ
-static void email_shutdown (void)
-{
-       collector_t *ptr;
 
-       if (disabled)
-               return;
-
-       close (connector_socket);
-       pthread_kill (connector, SIGTERM);
+       return (0);
+} /* int email_init */
 
-       pthread_mutex_lock (&active_mutex);
+static int email_shutdown (void)
+{
+       int i = 0;
 
-       for (ptr = active.head; NULL != ptr; ptr = ptr->next) {
-               close (ptr->socket);
-               pthread_kill (ptr->thread, SIGTERM);
+       if (connector != ((pthread_t) 0)) {
+               pthread_kill (connector, SIGTERM);
+               connector = (pthread_t) 0;
        }
 
-       pthread_mutex_unlock (&active_mutex);
+       if (connector_socket >= 0) {
+               close (connector_socket);
+               connector_socket = -1;
+       }
 
-       unlink (SOCK_PATH);
-       return;
-} /* static void email_shutdown (void) */
-#endif /* EMAIL_HAVE_READ */
+       /* don't allow any more connections to be processed */
+       pthread_mutex_lock (&conns_mutex);
 
-static void count_write (char *host, char *inst, char *val)
-{
-       char file[BUFSIZE] = "";
-       int  len           = 0;
+       if (collectors != NULL) {
+               for (i = 0; i < max_conns; ++i) {
+                       if (collectors[i] == NULL)
+                               continue;
 
-       len = snprintf (file, BUFSIZE, COUNT_FILE, inst);
-       if ((len < 0) || (len >= BUFSIZE))
-               return;
+                       if (collectors[i]->thread != ((pthread_t) 0)) {
+                               pthread_kill (collectors[i]->thread, SIGTERM);
+                               collectors[i]->thread = (pthread_t) 0;
+                       }
 
-       rrd_update_file (host, file, val, count_ds_def, count_ds_num);
-       return;
-} /* static void email_write (char *host, char *inst, char *val) */
+                       if (collectors[i]->socket >= 0) {
+                               close (collectors[i]->socket);
+                               collectors[i]->socket = -1;
+                       }
+               }
+       } /* if (collectors != NULL) */
 
-static void size_write (char *host, char *inst, char *val)
-{
-       char file[BUFSIZE] = "";
-       int  len           = 0;
+       pthread_mutex_unlock (&conns_mutex);
 
-       len = snprintf (file, BUFSIZE, SIZE_FILE, inst);
-       if ((len < 0) || (len >= BUFSIZE))
-               return;
+       unlink (sock_file);
+       errno = 0;
 
-       rrd_update_file (host, file, val, size_ds_def, size_ds_num);
-       return;
-} /* static void size_write (char *host, char *inst, char *val) */
+       return (0);
+} /* static void email_shutdown (void) */
 
-static void score_write (char *host, char *inst, char *val)
+static void email_submit (const char *type, const char *type_instance, gauge_t value)
 {
-       rrd_update_file (host, SCORE_FILE, val, score_ds_def, score_ds_num);
-       return;
-} /* static void score_write (char *host, char *inst, char *val) */
-
-static void check_write (char *host, char *inst, char *val)
+       value_t values[1];
+       value_list_t vl = VALUE_LIST_INIT;
+
+       values[0].gauge = value;
+
+       vl.values = values;
+       vl.values_len = 1;
+       vl.time = time (NULL);
+       sstrncpy (vl.host, hostname_g, sizeof (vl.host));
+       sstrncpy (vl.plugin, "email", sizeof (vl.plugin));
+       strncpy (vl.type_instance, type_instance, sizeof (vl.type_instance));
+
+       plugin_dispatch_values (type, &vl);
+} /* void email_submit */
+
+/* Copy list l1 to list l2. l2 may partly exist already, but it is assumed
+ * that neither the order nor the name of any element of either list is
+ * changed and no elements are deleted. The values of l1 are reset to zero
+ * after they have been copied to l2. */
+static void copy_type_list (type_list_t *l1, type_list_t *l2)
 {
-       char file[BUFSIZE] = "";
-       int  len           = 0;
+       type_t *ptr1;
+       type_t *ptr2;
 
-       len = snprintf (file, BUFSIZE, CHECK_FILE, inst);
-       if ((len < 0) || (len >= BUFSIZE))
-               return;
+       type_t *last = NULL;
 
-       rrd_update_file (host, file, val, check_ds_def, check_ds_num);
-       return;
-} /* static void check_write (char *host, char *inst, char *val) */
+       for (ptr1 = l1->head, ptr2 = l2->head; NULL != ptr1;
+                       ptr1 = ptr1->next, last = ptr2, ptr2 = ptr2->next) {
+               if (NULL == ptr2) {
+                       ptr2 = (type_t *)smalloc (sizeof (type_t));
+                       ptr2->name = NULL;
+                       ptr2->next = NULL;
 
-#if EMAIL_HAVE_READ
-static void type_submit (char *plugin, char *inst, int value)
-{
-       char buf[BUFSIZE] = "";
-       int  len          = 0;
+                       if (NULL == last) {
+                               l2->head = ptr2;
+                       }
+                       else {
+                               last->next = ptr2;
+                       }
 
-       if (0 == value)
-               return;
+                       l2->tail = ptr2;
+               }
 
-       len = snprintf (buf, BUFSIZE, "%u:%i", (unsigned int)curtime, value);
-       if ((len < 0) || (len >= BUFSIZE))
-               return;
+               if (NULL == ptr2->name) {
+                       ptr2->name = sstrdup (ptr1->name);
+               }
 
-       plugin_submit (plugin, inst, buf);
+               ptr2->value = ptr1->value;
+               ptr1->value = 0;
+       }
        return;
-} /* static void type_submit (char *, char *, int) */
+}
 
-static void score_submit (double value)
+static int email_read (void)
 {
-       char buf[BUFSIZE] = "";
-       int  len          = 0;
+       type_t *ptr;
 
-       if (0.0 == value)
-               return;
+       double score_old;
+       int score_count_old;
 
-       len = snprintf (buf, BUFSIZE, "%u:%.2f", (unsigned int)curtime, value);
-       if ((len < 0) || (len >= BUFSIZE))
-               return;
+       static type_list_t *cnt;
+       static type_list_t *sz;
+       static type_list_t *chk;
 
-       plugin_submit ("email_spam_score", NULL, buf);
-       return;
-}
+       if (disabled)
+               return (-1);
 
-static void email_read (void)
-{
-       type_t *ptr;
+       if (NULL == cnt) {
+               cnt = (type_list_t *)smalloc (sizeof (type_list_t));
+               cnt->head = NULL;
+       }
 
-       if (disabled)
-               return;
+       if (NULL == sz) {
+               sz = (type_list_t *)smalloc (sizeof (type_list_t));
+               sz->head = NULL;
+       }
 
+       if (NULL == chk) {
+               chk = (type_list_t *)smalloc (sizeof (type_list_t));
+               chk->head = NULL;
+       }
+
+       /* email count */
        pthread_mutex_lock (&count_mutex);
 
-       for (ptr = count.head; NULL != ptr; ptr = ptr->next) {
-               type_submit ("email_count", ptr->name, ptr->value);
-               ptr->value = 0;
-       }
+       copy_type_list (&count, cnt);
 
        pthread_mutex_unlock (&count_mutex);
 
+       for (ptr = cnt->head; NULL != ptr; ptr = ptr->next) {
+               email_submit ("email_count", ptr->name, ptr->value);
+       }
+
+       /* email size */
        pthread_mutex_lock (&size_mutex);
 
-       for (ptr = size.head; NULL != ptr; ptr = ptr->next) {
-               type_submit ("email_size", ptr->name, ptr->value);
-               ptr->value = 0;
-       }
+       copy_type_list (&size, sz);
 
        pthread_mutex_unlock (&size_mutex);
 
+       for (ptr = sz->head; NULL != ptr; ptr = ptr->next) {
+               email_submit ("email_size", ptr->name, ptr->value);
+       }
+
+       /* spam score */
        pthread_mutex_lock (&score_mutex);
 
-       score_submit (score);
+       score_old = score;
+       score_count_old = score_count;
        score = 0.0;
        score_count = 0;
 
        pthread_mutex_unlock (&score_mutex);
 
+       if (score_count_old > 0)
+               email_submit ("spam_score", "", score_old);
+
+       /* spam checks */
        pthread_mutex_lock (&check_mutex);
 
-       for (ptr = check.head; NULL != ptr; ptr = ptr->next) {
-               type_submit ("email_spam_check", ptr->name, ptr->value);
-               ptr->value = 0;
-       }
+       copy_type_list (&check, chk);
 
        pthread_mutex_unlock (&check_mutex);
-       return;
-} /* static void read (void) */
-#else /* if !EMAIL_HAVE_READ */
-# define email_read NULL
-#endif
+
+       for (ptr = chk->head; NULL != ptr; ptr = ptr->next)
+               email_submit ("spam_check", ptr->name, ptr->value);
+
+       return (0);
+} /* int email_read */
 
 void module_register (void)
 {
-       plugin_register (MODULE_NAME, email_init, email_read, NULL);
-       plugin_register ("email_count", NULL, NULL, count_write);
-       plugin_register ("email_size", NULL, NULL, size_write);
-       plugin_register ("email_spam_score", NULL, NULL, score_write);
-       plugin_register ("email_spam_check", NULL, NULL, check_write);
-#if EMAIL_HAVE_READ
-       plugin_register_shutdown (MODULE_NAME, email_shutdown);
-       cf_register (MODULE_NAME, email_config, config_keys, config_keys_num);
-#endif /* EMAIL_HAVE_READ */
-       return;
-} /* void module_register (void) */
+       plugin_register_config ("email", email_config, config_keys, config_keys_num);
+       plugin_register_init ("email", email_init);
+       plugin_register_read ("email", email_read);
+       plugin_register_shutdown ("email", email_shutdown);
+} /* void module_register */
 
 /* vim: set sw=4 ts=4 tw=78 noexpandtab : */
-