unixsock plugin: Added a first version of a UNIX-socket output plugin.

The goal is to build a nagios-interface on top of this.

diff --git a/configure.in b/configure.in
index 0b0aa8904f2515c5e45d26459f67b10105b14e04..23f0e59e8502fc48d5354e236a042ece8b1f44b2 100644 (file)
--- a/configure.in
+++ b/configure.in
@@ -1005,6 +1005,7 @@ AC_COLLECTD([serial],    [disable], [module], [serial statistics])
 AC_COLLECTD([swap],      [disable], [module], [swap statistics])
 AC_COLLECTD([tape],      [disable], [module], [tape statistics])
 AC_COLLECTD([traffic],   [disable], [module], [system traffic statistics])
+AC_COLLECTD([unixsock],  [disable], [module], [UNIX socket plugin])
 AC_COLLECTD([users],     [disable], [module], [user count statistics])
 AC_COLLECTD([vserver],   [disable], [module], [vserver statistics])
 AC_COLLECTD([wireless],  [disable], [module], [wireless link statistics])
@@ -1061,6 +1062,7 @@ Configuration:
     swap  . . . . . . . $enable_swap
     tape  . . . . . . . $enable_tape
     traffic . . . . . . $enable_traffic
+    unixsock  . . . . . $enable_unixsock
     users . . . . . . . $enable_users
     vserver . . . . . . $enable_vserver
     wireless  . . . . . $enable_wireless

diff --git a/src/Makefile.am b/src/Makefile.am
index 87dcec07984122862f133d780dc33f8d608324c3..d9d90ef14271286c35e69bfc0de308fe58d347af 100644 (file)
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -18,6 +18,7 @@ collectd_SOURCES = collectd.c collectd.h \
                   plugin.c plugin.h \
                   configfile.c configfile.h
 collectd_CPPFLAGS = $(LTDLINCL)
+collectd_CPPFLAGS += -DPREFIX='"${prefix}"'
 collectd_CPPFLAGS += -DCONFIGFILE='"${sysconfdir}/${PACKAGE_NAME}.conf"'
 collectd_CPPFLAGS += -DPKGLOCALSTATEDIR='"${localstatedir}/lib/${PACKAGE_NAME}"'
 if BUILD_FEATURE_DAEMON
@@ -430,6 +431,17 @@ traffic_la_LDFLAGS += -lstatgrab
 endif
 endif
 
+if BUILD_MODULE_UNIXSOCK
+pkglib_LTLIBRARIES += unixsock.la
+unixsock_la_SOURCES = unixsock.c
+unixsock_la_LDFLAGS = -module -avoid-version
+if BUILD_WITH_LIBPTHREAD
+unixsock_la_LDFLAGS += -lpthread
+endif
+collectd_LDADD += "-dlopen" unixsock.la
+collectd_DEPENDENCIES += unixsock.la
+endif
+
 if BUILD_MODULE_USERS
 pkglib_LTLIBRARIES += users.la
 users_la_SOURCES = users.c

diff --git a/src/unixsock.c b/src/unixsock.c
new file mode 100644 (file)
index 0000000..84d49fd
--- /dev/null
+++ b/src/unixsock.c
@@ -0,0 +1,656 @@
+/**
+ * collectd - src/unixsock.c
+ * Copyright (C) 2007  Florian octo Forster
+ *
+ * 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; 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
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ *
+ * Author:
+ *   Florian octo Forster <octo at verplant.org>
+ **/
+
+#include "collectd.h"
+#include "common.h"
+#include "plugin.h"
+#include "configfile.h"
+#include "utils_debug.h"
+
+/* Folks without pthread will need to disable this plugin. */
+#include <pthread.h>
+
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/poll.h>
+
+#include <grp.h>
+
+#ifndef UNIX_PATH_MAX
+# define UNIX_PATH_MAX sizeof (((struct sockaddr_un *)0)->sun_path)
+#endif
+
+#define US_DEFAULT_PATH PREFIX"/var/run/"PACKAGE_NAME"-unixsock"
+
+/*
+ * Private data structures
+ */
+/* linked list of cached values */
+typedef struct value_cache_s
+{
+       char       name[4*DATA_MAX_NAME_LEN];
+       int        values_num;
+       gauge_t   *gauge;
+       counter_t *counter;
+       time_t     time;
+       struct value_cache_s *next;
+} value_cache_t;
+
+/*
+ * Private variables
+ */
+/* valid configuration file keys */
+static const char *config_keys[] =
+{
+       "SocketFile",
+       "SocketGroup",
+       "SocketPerms",
+       NULL
+};
+static int config_keys_num = 3;
+
+/* socket configuration */
+static int   sock_fd    = -1;
+static char *sock_file  = NULL;
+static char *sock_group = NULL;
+static int   sock_perms = S_IRWXU | S_IRWXG;
+
+static pthread_t listen_thread = -1;
+
+/* Linked list and auxilliary variables for saving values */
+static value_cache_t   *cache_head = NULL;
+static pthread_mutex_t  cache_lock = PTHREAD_MUTEX_INITIALIZER;
+static unsigned int     cache_oldest = UINT_MAX;
+
+/*
+ * Functions
+ */
+static value_cache_t *cache_search (const char *name)
+{
+       value_cache_t *vc;
+
+       for (vc = cache_head; vc != NULL; vc = vc->next)
+       {
+               if (strcmp (vc->name, name) == 0)
+                       break;
+       } /* for vc = cache_head .. NULL */
+
+       return (vc);
+} /* value_cache_t *cache_search */
+
+static int cache_alloc_name (char *ret, int ret_len,
+               const char *plugin, const char *plugin_instance,
+               const char *type, const char *type_instance)
+{
+       int  status;
+
+       assert (plugin != NULL);
+       assert (type != NULL);
+
+       if ((plugin_instance == NULL) || (strlen (plugin_instance) == 0))
+       {
+               if ((type_instance == NULL) || (strlen (type_instance) == 0))
+                       status = snprintf (ret, ret_len, "%s/%s",
+                                       plugin, type);
+               else
+                       status = snprintf (ret, ret_len, "%s/%s-%s",
+                                       plugin, type, type_instance);
+       }
+       else
+       {
+               if ((type_instance == NULL) || (strlen (type_instance) == 0))
+                       status = snprintf (ret, ret_len, "%s-%s/%s",
+                                       plugin, plugin_instance, type);
+               else
+                       status = snprintf (ret, ret_len, "%s-%s/%s-%s",
+                                       plugin, plugin_instance,
+                                       type, type_instance);
+       }
+
+       if ((status < 1) || (status >= ret_len))
+               return (-1);
+       return (0);
+} /* int cache_alloc_name */
+
+static int cache_insert (const data_set_t *ds, const value_list_t *vl)
+{
+       /* We're called from `cache_update' so we don't need to lock the mutex */
+       value_cache_t *vc;
+       int i;
+
+       DBG ("ds->ds_num = %i; vl->values_len = %i;",
+                       ds->ds_num, vl->values_len);
+       assert (ds->ds_num == vl->values_len);
+
+       vc = (value_cache_t *) malloc (sizeof (value_cache_t));
+       if (vc == NULL)
+       {
+               pthread_mutex_unlock (&cache_lock);
+               syslog (LOG_ERR, "unixsock plugin: malloc failed: %s",
+                               strerror (errno));
+               return (-1);
+       }
+
+       vc->gauge = (gauge_t *) malloc (sizeof (gauge_t) * vl->values_len);
+       if (vc->gauge == NULL)
+       {
+               pthread_mutex_unlock (&cache_lock);
+               syslog (LOG_ERR, "unixsock plugin: malloc failed: %s",
+                               strerror (errno));
+               free (vc);
+               return (-1);
+       }
+
+       vc->counter = (counter_t *) malloc (sizeof (counter_t) * vl->values_len);
+       if (vc->counter == NULL)
+       {
+               pthread_mutex_unlock (&cache_lock);
+               syslog (LOG_ERR, "unixsock plugin: malloc failed: %s",
+                               strerror (errno));
+               free (vc->gauge);
+               free (vc);
+               return (-1);
+       }
+
+       if (cache_alloc_name (vc->name, sizeof (vc->name),
+                               vl->plugin, vl->plugin_instance,
+                               ds->type, vl->type_instance) != 0)
+       {
+               pthread_mutex_unlock (&cache_lock);
+               syslog (LOG_ERR, "unixsock plugin: cache_alloc_name failed.");
+               free (vc->counter);
+               free (vc->gauge);
+               free (vc);
+               return (-1);
+       }
+
+       for (i = 0; i < ds->ds_num; i++)
+       {
+               if (ds->ds[i].type == DS_TYPE_COUNTER)
+               {
+                       vc->gauge[i] = 0.0;
+                       vc->counter[i] = vl->values[i].counter;
+               }
+               else if (ds->ds[i].type == DS_TYPE_GAUGE)
+               {
+                       vc->gauge[i] = vl->values[i].gauge;
+                       vc->counter[i] = 0;
+               }
+               else
+               {
+                       vc->gauge[i] = 0.0;
+                       vc->counter[i] = 0;
+               }
+       }
+       vc->values_num = ds->ds_num;
+
+       vc->next = cache_head;
+       cache_head = vc;
+
+       vc->time = vl->time;
+       if (vc->time < cache_oldest)
+               cache_oldest = vc->time;
+
+       pthread_mutex_unlock (&cache_lock);
+       return (0);
+} /* int cache_insert */
+
+static int cache_update (const data_set_t *ds, const value_list_t *vl)
+{
+       char name[4*DATA_MAX_NAME_LEN];;
+       value_cache_t *vc;
+       int i;
+
+       if (cache_alloc_name (name, sizeof (name),
+                               vl->plugin, vl->plugin_instance,
+                               ds->type, vl->type_instance) != 0)
+               return (-1);
+
+       pthread_mutex_lock (&cache_lock);
+
+       vc = cache_search (name);
+
+       if (vc == NULL)
+               return (cache_insert (ds, vl));
+
+       assert (vc->values_num == ds->ds_num);
+       assert (vc->values_num == vl->values_len);
+
+       /*
+        * Update the values. This is possibly a lot more that you'd expect
+        * because we honor min and max values and handle counter overflows here.
+        */
+       for (i = 0; i < ds->ds_num; i++)
+       {
+               if (ds->ds[i].type == DS_TYPE_COUNTER)
+               {
+                       if (vl->values[i].counter < vc->counter[i])
+                       {
+                               if (vl->values[i].counter <= 4294967295U)
+                               {
+                                       vc->gauge[i] = ((4294967295U - vl->values[i].counter)
+                                                       + vc->counter[i]) / (vl->time - vc->time);
+                               }
+                               else
+                               {
+                                       vc->gauge[i] = ((18446744073709551615ULL - vl->values[i].counter)
+                                               + vc->counter[i]) / (vl->time - vc->time);
+                               }
+                       }
+                       else
+                       {
+                               vc->gauge[i] = (vl->values[i].counter - vc->counter[i])
+                                       / (vl->time - vc->time);
+                       }
+
+                       DBG ("name = %s; old counter: %llu; new counter: %llu; rate: %lf;",
+                                       name,
+                                       vc->counter[i], vl->values[i].counter,
+                                       vc->gauge[i]);
+
+                       vc->counter[i] = vl->values[i].counter;
+               }
+               else if (ds->ds[i].type == DS_TYPE_GAUGE)
+               {
+                       vc->gauge[i] = vl->values[i].gauge;
+                       vc->counter[i] = 0;
+
+                       DBG ("name, %s; gauge: %lf;",
+                                       name, vc->gauge[i]);
+               }
+               else
+               {
+                       vc->gauge[i] = NAN;
+                       vc->counter[i] = 0;
+               }
+
+               if ((vc->gauge[i] == NAN)
+                               || ((ds->ds[i].min != NAN) && (vc->gauge[i] < ds->ds[i].min))
+                               || ((ds->ds[i].max != NAN) && (vc->gauge[i] > ds->ds[i].max)))
+                       vc->gauge[i] = NAN;
+       } /* for i = 0 .. ds->ds_num */
+
+       vc->time = vl->time;
+
+       if (vc->time < cache_oldest)
+               cache_oldest = vc->time;
+
+       pthread_mutex_unlock (&cache_lock);
+       return (0);
+} /* int cache_update */
+
+static void cache_flush (int max_age)
+{
+       value_cache_t *this;
+       value_cache_t *prev;
+       time_t now;
+
+       pthread_mutex_lock (&cache_lock);
+
+       now = time (NULL);
+
+       if ((now - cache_oldest) <= max_age)
+       {
+               pthread_mutex_unlock (&cache_lock);
+               return;
+       }
+       
+       cache_oldest = now;
+
+       prev = NULL;
+       this = cache_head;
+
+       while (this != NULL)
+       {
+               if ((now - this->time) <= max_age)
+               {
+                       if (this->time < cache_oldest)
+                               cache_oldest = this->time;
+
+                       prev = this;
+                       this = this->next;
+                       continue;
+               }
+
+               if (prev == NULL)
+                       cache_head = this->next;
+               else
+                       prev->next = this->next;
+
+               free (this->gauge);
+               free (this->counter);
+               free (this);
+
+               if (prev == NULL)
+                       this = cache_head;
+               else
+                       this = prev->next;
+       } /* while (this != NULL) */
+
+       pthread_mutex_unlock (&cache_lock);
+} /* int cache_flush */
+
+static int us_open_socket (void)
+{
+       struct sockaddr_un sa;
+       int status;
+
+       sock_fd = socket (PF_UNIX, SOCK_STREAM, 0);
+       if (sock_fd < 0)
+       {
+               syslog (LOG_ERR, "unixsock plugin: socket failed: %s",
+                               strerror (errno));
+               return (-1);
+       }
+
+       memset (&sa, '\0', sizeof (sa));
+       sa.sun_family = AF_UNIX;
+       strncpy (sa.sun_path, (sock_file != NULL) ? sock_file : US_DEFAULT_PATH,
+                       sizeof (sa.sun_path) - 1);
+       /* unlink (sa.sun_path); */
+
+       status = bind (sock_fd, (struct sockaddr *) &sa, sizeof (sa));
+       if (status != 0)
+       {
+               DBG ("bind failed: %s; sa.sun_path = %s",
+                               strerror (errno), sa.sun_path);
+               syslog (LOG_ERR, "unixsock plugin: bind failed: %s",
+                               strerror (errno));
+               close (sock_fd);
+               sock_fd = -1;
+               return (-1);
+       }
+
+       status = listen (sock_fd, 8);
+       if (status != 0)
+       {
+               syslog (LOG_ERR, "unixsock plugin: listen failed: %s",
+                               strerror (errno));
+               close (sock_fd);
+               sock_fd = -1;
+               return (-1);
+       }
+
+       do
+       {
+               struct group *g;
+
+               errno = 0;
+               g = getgrnam ((sock_group != NULL) ? sock_group : COLLECTD_GRP_NAME);
+
+               if (errno != 0)
+               {
+                       syslog (LOG_WARNING, "unixsock plugin: getgrnam (%s) failed: %s",
+                                       (sock_group != NULL) ? sock_group : COLLECTD_GRP_NAME,
+                                       strerror (errno));
+                       break;
+               }
+
+               if (g == NULL)
+                       break;
+
+               if (chown ((sock_file != NULL) ? sock_file : US_DEFAULT_PATH,
+                                       (uid_t) -1, g->gr_gid) != 0)
+               {
+                       syslog (LOG_WARNING, "unixsock plugin: chown (%s, -1, %i) failed: %s",
+                                       (sock_file != NULL) ? sock_file : US_DEFAULT_PATH,
+                                       (int) g->gr_gid,
+                                       strerror (errno));
+               }
+       } while (0);
+
+       return (0);
+} /* int us_open_socket */
+
+static int us_handle_getval (FILE *fh, char **fields, int fields_num)
+{
+       char *plugin = fields[1];
+       char *plugin_instance;
+       char *type;
+       char *type_instance;
+       char  name[4*DATA_MAX_NAME_LEN];
+       value_cache_t *vc;
+       int   status;
+       int   i;
+
+       if (fields_num != 2)
+               return (-1);
+
+       type = strchr (plugin, '/');
+       if (type == NULL)
+               return (-1);
+       *type = '\0'; type++;
+
+       plugin_instance = strchr (plugin, '-');
+       if (plugin_instance != NULL)
+       {
+               *plugin_instance = '\0';
+               plugin_instance++;
+       }
+
+       type_instance = strchr (type, '-');
+       if (type_instance != NULL)
+       {
+               *type_instance = '\0';
+               type_instance++;
+       }
+
+       status = cache_alloc_name (name, sizeof (name),
+                       plugin, plugin_instance, type, type_instance);
+       if (status != 0)
+               return (-1);
+
+       pthread_mutex_lock (&cache_lock);
+
+       vc = cache_search (name);
+
+       fprintf (fh, "%i", vc->values_num);
+       for (i = 0; i < vc->values_num; i++)
+       {
+               if (vc->gauge[i] == NAN)
+                       fprintf (fh, " NaN");
+               else
+                       fprintf (fh, " %12e", vc->gauge[i]);
+       }
+
+       /* Free the mutex as soon as possible and definitely before flushing */
+       pthread_mutex_unlock (&cache_lock);
+
+       fprintf (fh, "\n");
+       fflush (fh);
+
+       return (0);
+} /* int us_handle_getval */
+
+static void *us_handle_client (void *arg)
+{
+       int fd;
+       FILE *fh;
+       char buffer[1024];
+       char *fields[128];
+       int   fields_num;
+
+       fd = *((int *) arg);
+       free (arg);
+       arg = NULL;
+
+       DBG ("Reading from fd #%i", fd);
+
+       fh = fdopen (fd, "r+");
+       if (fh == NULL)
+       {
+               syslog (LOG_ERR, "unixsock plugin: fdopen failed: %s",
+                               strerror (errno));
+               close (fd);
+               pthread_exit ((void *) 1);
+       }
+
+       while (fgets (buffer, sizeof (buffer), fh) != NULL)
+       {
+               DBG ("fgets -> buffer = %s", buffer);
+
+               fields_num = strsplit (buffer, fields,
+                               sizeof (fields) / sizeof (fields[0]));
+
+               if (fields_num < 1)
+               {
+                       close (fd);
+                       break;
+               }
+
+               if (strcasecmp (fields[0], "getval") == 0)
+               {
+                       us_handle_getval (fh, fields, fields_num);
+               }
+               else
+               {
+                       fprintf (fh, "Unknown command: %s\n", fields[0]);
+                       fflush (fh);
+               }
+       } /* while (fgets) */
+
+       DBG ("Exiting..");
+       close (fd);
+
+       pthread_exit ((void *) 0);
+} /* void *us_handle_client */
+
+static void *us_server_thread (void *arg)
+{
+       int  status;
+       int *remote_fd;
+       pthread_t th;
+
+       if (us_open_socket () != 0)
+               pthread_exit ((void *) 1);
+
+       while (42)
+       {
+               DBG ("Calling accept..");
+               status = accept (sock_fd, NULL, NULL);
+               if (status < 0)
+               {
+                       if (errno == EINTR)
+                               continue;
+
+                       syslog (LOG_ERR, "unixsock plugin: accept failed: %s",
+                                       strerror (errno));
+                       close (sock_fd);
+                       sock_fd = -1;
+                       pthread_exit ((void *) 1);
+               }
+
+               remote_fd = (int *) malloc (sizeof (int));
+               if (remote_fd == NULL)
+               {
+                       syslog (LOG_WARNING, "unixsock plugin: malloc failed: %s",
+                                       strerror (errno));
+                       close (status);
+                       continue;
+               }
+               *remote_fd = status;
+
+               DBG ("Spawning child to handle connection on fd #%i", *remote_fd);
+
+               status = pthread_create (&th, NULL, us_handle_client, (void *) remote_fd);
+               if (status != 0)
+               {
+                       syslog (LOG_WARNING, "unixsock plugin: pthread_create failed: %s",
+                                       strerror (status));
+                       close (*remote_fd);
+                       free (remote_fd);
+                       continue;
+               }
+       } /* while (42) */
+
+       return ((void *) 0);
+} /* void *us_server_thread */
+
+static int us_config (const char *key, const char *val)
+{
+       if (strcasecmp (key, "SocketFile") == 0)
+       {
+               sfree (sock_file);
+               sock_file = strdup (val);
+       }
+       else if (strcasecmp (key, "SocketGroup") == 0)
+       {
+               sfree (sock_group);
+               sock_group = strdup (val);
+       }
+       else if (strcasecmp (key, "SocketPerms") == 0)
+       {
+               sock_perms = (int) strtol (val, NULL, 8);
+       }
+       else
+       {
+               return (-1);
+       }
+
+       return (0);
+} /* int us_config */
+
+static int us_init (void)
+{
+       int status;
+
+       status = pthread_create (&listen_thread, NULL, us_server_thread, NULL);
+       if (status != 0)
+       {
+               syslog (LOG_ERR, "unixsock plugin: pthread_create failed: %s",
+                               strerror (status));
+               return (-1);
+       }
+
+       return (0);
+} /* int us_init */
+
+static int us_shutdown (void)
+{
+       void *ret;
+
+       if (listen_thread >= 0)
+       {
+               pthread_kill (listen_thread, SIGTERM);
+               pthread_join (listen_thread, &ret);
+       }
+
+       return (0);
+} /* int us_shutdown */
+
+static int us_write (const data_set_t *ds, const value_list_t *vl)
+{
+       cache_update (ds, vl);
+       cache_flush (2 * atoi (COLLECTD_STEP));
+
+       return (0);
+}
+
+void module_register (void)
+{
+       plugin_register_config ("unixsock", us_config,
+                       config_keys, config_keys_num);
+       plugin_register_init ("unixsock", us_init);
+       plugin_register_write ("unixsock", us_write);
+       plugin_register_shutdown ("unixsock", us_shutdown);
+} /* void module_register (void) */
+
+/* vim: set sw=4 ts=4 sts=4 tw=78 : */