X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=src%2Fexec.c;h=5eae906bee3f12ca74faeb07382488de7f36c6f6;hb=9d5a7847b03d78a94b6a0b153abeb630b4b94ddd;hp=5bddfc5920ff9a09ed33c3b7ded80c1b05adab71;hpb=06adec208286b5a136ffa5c5f3832c35e9f62844;p=collectd.git

diff --git a/src/exec.c b/src/exec.c
index 5bddfc59..5eae906b 100644
--- a/src/exec.c
+++ b/src/exec.c
@@ -1,6 +1,6 @@
 /**
  * collectd - src/exec.c
- * Copyright (C) 2007  Florian octo Forster
+ * Copyright (C) 2007,2008  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
@@ -23,160 +23,258 @@
 #include "common.h"
 #include "plugin.h"
 
+#include "utils_cmd_putval.h"
+#include "utils_cmd_putnotif.h"
+
 #include <sys/types.h>
 #include <pwd.h>
+#include <grp.h>
 #include <signal.h>
 
 #include <pthread.h>
 
+#define PL_NORMAL        0x01
+#define PL_NOTIF_ACTION  0x02
+
+#define PL_RUNNING       0x10
+
 /*
  * Private data types
  */
+/*
+ * Access to this structure is serialized using the `pl_lock' lock and the
+ * `PL_RUNNING' flag. The execution of notifications is *not* serialized, so
+ * all functions used to handle notifications MUST NOT write to this structure.
+ * The `pid' and `status' fields are thus unused if the `PL_NOTIF_ACTION' flag
+ * is set.
+ * The `PL_RUNNING' flag is set in `exec_read' and unset in `exec_read_one'.
+ */
 struct program_list_s;
 typedef struct program_list_s program_list_t;
 struct program_list_s
 {
   char           *user;
+  char           *group;
   char           *exec;
+  char          **argv;
   int             pid;
+  int             status;
+  int             flags;
   program_list_t *next;
 };
 
+typedef struct program_list_and_notification_s
+{
+  program_list_t *pl;
+  notification_t n;
+} program_list_and_notification_t;
+
 /*
  * Private variables
  */
-static data_source_t dsrc_counter[1] =
-{
-  {"value", DS_TYPE_COUNTER, NAN, NAN}
-};
-
-static data_set_t ds_counter =
-{
-  "counter", STATIC_ARRAY_SIZE (dsrc_counter), dsrc_counter
-};
-
-static data_source_t dsrc_gauge[1] =
-{
-  {"value", DS_TYPE_GAUGE, NAN, NAN}
-};
-
-static data_set_t ds_gauge =
-{
-  "gauge", STATIC_ARRAY_SIZE (dsrc_gauge), dsrc_gauge
-};
-
-static const char *config_keys[] =
-{
-  "Exec"
-};
-static int config_keys_num = STATIC_ARRAY_SIZE (config_keys);
-
 static program_list_t *pl_head = NULL;
+static pthread_mutex_t pl_lock = PTHREAD_MUTEX_INITIALIZER;
 
 /*
  * Functions
  */
-static int exec_config (const char *key, const char *value)
+static void sigchld_handler (int signal) /* {{{ */
 {
-  if (strcasecmp ("Exec", key) == 0)
+  pid_t pid;
+  int status;
+  while ((pid = waitpid (-1, &status, WNOHANG)) > 0)
   {
     program_list_t *pl;
-    pl = (program_list_t *) malloc (sizeof (program_list_t));
-    if (pl == NULL)
-      return (1);
-    memset (pl, '\0', sizeof (program_list_t));
+    for (pl = pl_head; pl != NULL; pl = pl->next)
+      if (pl->pid == pid)
+	break;
+    if (pl != NULL)
+      pl->status = status;
+  } /* while (waitpid) */
+} /* void sigchld_handler }}} */
+
+static int exec_config_exec (oconfig_item_t *ci) /* {{{ */
+{
+  program_list_t *pl;
+  char buffer[128];
+  int i;
 
-    pl->user = strdup (value);
-    if (pl->user == NULL)
-    {
-      sfree (pl);
-      return (1);
-    }
+  if (ci->children_num != 0)
+  {
+    WARNING ("exec plugin: The config option `%s' may not be a block.",
+	ci->key);
+    return (-1);
+  }
+  if (ci->values_num < 2)
+  {
+    WARNING ("exec plugin: The config option `%s' needs at least two "
+	"arguments.", ci->key);
+    return (-1);
+  }
+  if ((ci->values[0].type != OCONFIG_TYPE_STRING)
+      || (ci->values[1].type != OCONFIG_TYPE_STRING))
+  {
+    WARNING ("exec plugin: The first two arguments to the `%s' option must "
+	"be string arguments.", ci->key);
+    return (-1);
+  }
+
+  pl = (program_list_t *) malloc (sizeof (program_list_t));
+  if (pl == NULL)
+  {
+    ERROR ("exec plugin: malloc failed.");
+    return (-1);
+  }
+  memset (pl, '\0', sizeof (program_list_t));
+
+  if (strcasecmp ("NotificationExec", ci->key) == 0)
+    pl->flags |= PL_NOTIF_ACTION;
+  else
+    pl->flags |= PL_NORMAL;
+
+  pl->user = strdup (ci->values[0].value.string);
+  if (pl->user == NULL)
+  {
+    ERROR ("exec plugin: strdup failed.");
+    sfree (pl);
+    return (-1);
+  }
+
+  pl->group = strchr (pl->user, ':');
+  if (pl->group != NULL)
+  {
+    *pl->group = '\0';
+    pl->group++;
+  }
+
+  pl->exec = strdup (ci->values[1].value.string);
+  if (pl->exec == NULL)
+  {
+    ERROR ("exec plugin: strdup failed.");
+    sfree (pl->user);
+    sfree (pl);
+    return (-1);
+  }
+
+  pl->argv = (char **) malloc (ci->values_num * sizeof (char *));
+  if (pl->argv == NULL)
+  {
+    ERROR ("exec plugin: malloc failed.");
+    sfree (pl->exec);
+    sfree (pl->user);
+    sfree (pl);
+    return (-1);
+  }
+  memset (pl->argv, '\0', ci->values_num * sizeof (char *));
 
-    pl->exec = strchr (pl->user, ' ');
-    if (pl->exec == NULL)
+  {
+    char *tmp = strrchr (ci->values[1].value.string, '/');
+    if (tmp == NULL)
+      strncpy (buffer, ci->values[1].value.string, sizeof (buffer));
+    else
+      strncpy (buffer, tmp + 1, sizeof (buffer));
+    buffer[sizeof (buffer) - 1] = '\0';
+  }
+  pl->argv[0] = strdup (buffer);
+  if (pl->argv[0] == NULL)
+  {
+    ERROR ("exec plugin: malloc failed.");
+    sfree (pl->argv);
+    sfree (pl->exec);
+    sfree (pl->user);
+    sfree (pl);
+    return (-1);
+  }
+
+  for (i = 1; i < (ci->values_num - 1); i++)
+  {
+    if (ci->values[i + 1].type == OCONFIG_TYPE_STRING)
     {
-      sfree (pl->user);
-      sfree (pl);
-      return (1);
+      pl->argv[i] = strdup (ci->values[i + 1].value.string);
     }
-    while (*pl->exec == ' ')
+    else
     {
-      *pl->exec = '\0';
-      pl->exec++;
+      if (ci->values[i + 1].type == OCONFIG_TYPE_NUMBER)
+      {
+	snprintf (buffer, sizeof (buffer), "%lf",
+	    ci->values[i + 1].value.number);
+      }
+      else
+      {
+	if (ci->values[i + 1].value.boolean)
+	  strncpy (buffer, "true", sizeof (buffer));
+	else
+	  strncpy (buffer, "false", sizeof (buffer));
+      }
+      buffer[sizeof (buffer) - 1] = '\0';
+
+      pl->argv[i] = strdup (buffer);
     }
 
-    if (*pl->exec == '\0')
+    if (pl->argv[i] == NULL)
     {
-      sfree (pl->user);
-      sfree (pl);
-      return (1);
+      ERROR ("exec plugin: strdup failed.");
+      break;
     }
+  } /* for (i) */
 
-    pl->next = pl_head;
-    pl_head = pl;
-  }
-  else
+  if (i < (ci->values_num - 1))
   {
+    while ((--i) >= 0)
+    {
+      sfree (pl->argv[i]);
+    }
+    sfree (pl->argv);
+    sfree (pl->exec);
+    sfree (pl->user);
+    sfree (pl);
     return (-1);
   }
 
-  return (0);
-} /* int exec_config */
-
-static void submit_counter (const char *type_instance, counter_t value)
-{
-  value_t values[1];
-  value_list_t vl = VALUE_LIST_INIT;
-
-  DEBUG ("type_instance = %s; value = %llu;", type_instance, value);
-
-  values[0].counter = value;
+  for (i = 0; pl->argv[i] != NULL; i++)
+  {
+    DEBUG ("exec plugin: argv[%i] = %s", i, pl->argv[i]);
+  }
 
-  vl.values = values;
-  vl.values_len = 1;
-  vl.time = time (NULL);
-  strcpy (vl.host, hostname_g);
-  strcpy (vl.plugin, "exec");
-  strcpy (vl.plugin_instance, "");
-  strncpy (vl.type_instance, type_instance, sizeof (vl.type_instance));
+  pl->next = pl_head;
+  pl_head = pl;
 
-  plugin_dispatch_values ("counter", &vl);
-} /* void submit_counter */
+  return (0);
+} /* int exec_config_exec }}} */
 
-static void submit_gauge (const char *type_instance, gauge_t value)
+static int exec_config (oconfig_item_t *ci) /* {{{ */
 {
-  value_t values[1];
-  value_list_t vl = VALUE_LIST_INIT;
-
-  DEBUG ("type_instance = %s; value = %lf;", type_instance, value);
+  int i;
 
-  values[0].gauge = value;
-
-  vl.values = values;
-  vl.values_len = 1;
-  vl.time = time (NULL);
-  strcpy (vl.host, hostname_g);
-  strcpy (vl.plugin, "exec");
-  strcpy (vl.plugin_instance, "");
-  strncpy (vl.type_instance, type_instance, sizeof (vl.type_instance));
+  for (i = 0; i < ci->children_num; i++)
+  {
+    oconfig_item_t *child = ci->children + i;
+    if ((strcasecmp ("Exec", child->key) == 0)
+	|| (strcasecmp ("NotificationExec", child->key) == 0))
+      exec_config_exec (child);
+    else
+    {
+      WARNING ("exec plugin: Unknown config option `%s'.", child->key);
+    }
+  } /* for (i) */
 
-  plugin_dispatch_values ("gauge", &vl);
-} /* void submit_counter */
+  return (0);
+} /* int exec_config }}} */
 
-static void exec_child (program_list_t *pl)
+static void exec_child (program_list_t *pl) /* {{{ */
 {
   int status;
   int uid;
-  char *arg0;
+  int gid;
+  int egid;
 
   struct passwd *sp_ptr;
   struct passwd sp;
-  char pwnambuf[2048];
+  char nambuf[2048];
   char errbuf[1024];
 
   sp_ptr = NULL;
-  status = getpwnam_r (pl->user, &sp, pwnambuf, sizeof (pwnambuf), &sp_ptr);
+  status = getpwnam_r (pl->user, &sp, nambuf, sizeof (nambuf), &sp_ptr);
   if (status != 0)
   {
     ERROR ("exec plugin: getpwnam_r failed: %s",
@@ -190,42 +288,121 @@ static void exec_child (program_list_t *pl)
   }
 
   uid = sp.pw_uid;
+  gid = sp.pw_gid;
   if (uid == 0)
   {
     ERROR ("exec plugin: Cowardly refusing to exec program as root.");
     exit (-1);
   }
 
-  status = setuid (uid);
+  /* The group configured in the configfile is set as effective group, because
+   * this way the forked process can (re-)gain the user's primary group. */
+  egid = -1;
+  if (NULL != pl->group)
+  {
+    if ('\0' != *pl->group) {
+      struct group *gr_ptr = NULL;
+      struct group gr;
+
+      status = getgrnam_r (pl->group, &gr, nambuf, sizeof (nambuf), &gr_ptr);
+      if (0 != status)
+      {
+	ERROR ("exec plugin: getgrnam_r failed: %s",
+	    sstrerror (errno, errbuf, sizeof (errbuf)));
+	exit (-1);
+      }
+      if (NULL == gr_ptr)
+      {
+	ERROR ("exec plugin: No such group: `%s'", pl->group);
+	exit (-1);
+      }
+
+      egid = gr.gr_gid;
+    }
+    else
+    {
+      egid = gid;
+    }
+  } /* if (pl->group == NULL) */
+
+#if HAVE_SETGROUPS
+  if (getuid () == 0)
+  {
+    gid_t  glist[2];
+    size_t glist_len;
+
+    glist[0] = gid;
+    glist_len = 1;
+
+    if ((gid != egid) && (egid != -1))
+    {
+      glist[1] = egid;
+      glist_len = 2;
+    }
+
+    setgroups (glist_len, glist);
+  }
+#endif /* HAVE_SETGROUPS */
+
+  status = setgid (gid);
   if (status != 0)
   {
-    ERROR ("exec plugin: setuid failed: %s",
-	sstrerror (errno, errbuf, sizeof (errbuf)));
+    ERROR ("exec plugin: setgid (%i) failed: %s",
+	gid, sstrerror (errno, errbuf, sizeof (errbuf)));
     exit (-1);
   }
 
-  arg0 = strrchr (pl->exec, '/');
-  if (arg0 != NULL)
-    arg0++;
-  if ((arg0 == NULL) || (*arg0 == '\0'))
-    arg0 = pl->exec;
+  if (egid != -1)
+  {
+    status = setegid (egid);
+    if (status != 0)
+    {
+      ERROR ("exec plugin: setegid (%i) failed: %s",
+	  egid, sstrerror (errno, errbuf, sizeof (errbuf)));
+      exit (-1);
+    }
+  }
 
-  status = execlp (pl->exec, arg0, (char *) 0);
+  status = setuid (uid);
+  if (status != 0)
+  {
+    ERROR ("exec plugin: setuid (%i) failed: %s",
+	uid, sstrerror (errno, errbuf, sizeof (errbuf)));
+    exit (-1);
+  }
+
+  status = execvp (pl->exec, pl->argv);
 
   ERROR ("exec plugin: exec failed: %s",
       sstrerror (errno, errbuf, sizeof (errbuf)));
   exit (-1);
-} /* void exec_child */
+} /* void exec_child }}} */
 
-static int fork_child (program_list_t *pl)
+/*
+ * Creates two pipes (one for reading, ong for writing), forks a child, sets up
+ * the pipes so that fd_in is connected to STDIN of the child and fd_out is
+ * connected to STDOUT and STDERR of the child. Then is calls `exec_child'.
+ */
+static int fork_child (program_list_t *pl, int *fd_in, int *fd_out) /* {{{ */
 {
-  int fd_pipe[2];
+  int fd_pipe_in[2];
+  int fd_pipe_out[2];
   int status;
+  int pid;
 
   if (pl->pid != 0)
     return (-1);
 
-  status = pipe (fd_pipe);
+  status = pipe (fd_pipe_in);
+  if (status != 0)
+  {
+    char errbuf[1024];
+    ERROR ("exec plugin: pipe failed: %s",
+	sstrerror (errno, errbuf, sizeof (errbuf)));
+    return (-1);
+  }
+
+  status = pipe (fd_pipe_out);
   if (status != 0)
   {
     char errbuf[1024];
@@ -234,44 +411,113 @@ static int fork_child (program_list_t *pl)
     return (-1);
   }
 
-  pl->pid = fork ();
-  if (pl->pid < 0)
+  pid = fork ();
+  if (pid < 0)
   {
     char errbuf[1024];
     ERROR ("exec plugin: fork failed: %s",
 	sstrerror (errno, errbuf, sizeof (errbuf)));
     return (-1);
   }
-  else if (pl->pid == 0)
+  else if (pid == 0)
   {
-    close (fd_pipe[0]);
+    int fd_num;
+    int fd;
 
-    /* Connect the pipe to STDOUT and STDERR */
-    if (fd_pipe[1] != STDOUT_FILENO)
-      dup2 (fd_pipe[1], STDOUT_FILENO);
-    if (fd_pipe[1] != STDERR_FILENO)
-      dup2 (fd_pipe[1], STDERR_FILENO);
-    if ((fd_pipe[1] != STDOUT_FILENO) && (fd_pipe[1] != STDERR_FILENO))
-      close (fd_pipe[1]);
+    /* Close all file descriptors but the pipe end we need. */
+    fd_num = getdtablesize ();
+    for (fd = 0; fd < fd_num; fd++)
+    {
+      if ((fd == fd_pipe_in[0]) || (fd == fd_pipe_out[1]))
+	continue;
+      close (fd);
+    }
+
+    /* If the `out' pipe has the filedescriptor STDIN we have to be careful
+     * with the `dup's below. So, if this is the case we have to handle the
+     * `out' pipe first. */
+    if (fd_pipe_out[1] == STDIN_FILENO)
+    {
+      int new_fileno = (fd_pipe_in[0] == STDOUT_FILENO)
+	? STDERR_FILENO : STDOUT_FILENO;
+      dup2 (fd_pipe_out[1], new_fileno);
+      close (fd_pipe_out[1]);
+      fd_pipe_out[1] = new_fileno;
+    }
+    /* Now `fd_pipe_out[1]' is either `STDOUT' or `STDERR', but definitely not
+     * `STDIN_FILENO'. */
+
+    /* Connect the `in' pipe to STDIN */
+    if (fd_pipe_in[0] != STDIN_FILENO)
+    {
+      dup2 (fd_pipe_in[0], STDIN_FILENO);
+      close (fd_pipe_in[0]);
+      fd_pipe_in[0] = STDIN_FILENO;
+    }
+
+    /* Now connect the `out' pipe to STDOUT and STDERR */
+    if (fd_pipe_out[1] != STDOUT_FILENO)
+      dup2 (fd_pipe_out[1], STDOUT_FILENO);
+    if (fd_pipe_out[1] != STDERR_FILENO)
+      dup2 (fd_pipe_out[1], STDERR_FILENO);
+
+    /* If the pipe has some FD that's something completely different, close it
+     * now. */
+    if ((fd_pipe_out[1] != STDOUT_FILENO) && (fd_pipe_out[1] != STDERR_FILENO))
+    {
+      close (fd_pipe_out[1]);
+      fd_pipe_out[1] = STDOUT_FILENO;
+    }
 
     exec_child (pl);
     /* does not return */
   }
 
-  close (fd_pipe[1]);
-  return (fd_pipe[0]);
-} /* int fork_child */
+  close (fd_pipe_in[0]);
+  close (fd_pipe_out[1]);
+
+  if (fd_in != NULL)
+    *fd_in = fd_pipe_in[1];
+  else
+    close (fd_pipe_in[1]);
+
+  if (fd_out != NULL)
+    *fd_out = fd_pipe_out[0];
+  else
+    close (fd_pipe_out[0]);
+
+  return (pid);
+} /* int fork_child }}} */
+
+static int parse_line (char *buffer) /* {{{ */
+{
+  char *fields[256];
+  int fields_num;
+
+  fields[0] = "PUTVAL";
+  fields_num = strsplit (buffer, fields + 1, STATIC_ARRAY_SIZE(fields) - 1);
+
+  if (strcasecmp (fields[1], "putval") == 0)
+    return (handle_putval (stdout, fields + 1, fields_num));
+  else if (strcasecmp (fields[1], "putnotif") == 0)
+    return (handle_putnotif (stdout, fields + 1, fields_num));
+
+  /* compatibility code */
+  return (handle_putval (stdout, fields, fields_num + 1));
+} /* int parse_line }}} */
 
-static void *exec_read_one (void *arg)
+static void *exec_read_one (void *arg) /* {{{ */
 {
   program_list_t *pl = (program_list_t *) arg;
   int fd;
   FILE *fh;
   char buffer[1024];
+  int status;
 
-  fd = fork_child (pl);
-  if (fd < 0)
+  status = fork_child (pl, NULL, &fd);
+  if (status < 0)
     pthread_exit ((void *) 1);
+  pl->pid = status;
 
   assert (pl->pid != 0);
 
@@ -282,63 +528,125 @@ static void *exec_read_one (void *arg)
     ERROR ("exec plugin: fdopen (%i) failed: %s", fd,
 	sstrerror (errno, errbuf, sizeof (errbuf)));
     kill (pl->pid, SIGTERM);
+    pl->pid = 0;
     close (fd);
     pthread_exit ((void *) 1);
   }
 
+  buffer[0] = '\0';
   while (fgets (buffer, sizeof (buffer), fh) != NULL)
   {
     int len;
-    char *type;
-    char *type_instance;
-    char *value;
-
-    DEBUG ("buffer = %s", buffer);
 
     len = strlen (buffer);
-    if (len < 5)
-      continue;
 
-    if (buffer[0] == '#')
-      continue;
+    /* Remove newline from end. */
+    while ((len > 0) && ((buffer[len - 1] == '\n')
+	  || (buffer[len - 1] == '\r')))
+      buffer[--len] = '\0';
 
-    type = buffer;
+    DEBUG ("exec plugin: exec_read_one: buffer = %s", buffer);
 
-    type_instance = strchr (type, ',');
-    if (type_instance == NULL)
-      continue;
-    *type_instance = '\0';
-    type_instance++;
+    parse_line (buffer);
+  } /* while (fgets) */
 
-    if ((strcasecmp ("counter", type) != 0)
-	&& (strcasecmp ("gauge", type) != 0))
-    {
-      WARNING ("exec plugin: Received invalid type: %s", type);
-      continue;
-    }
+  fclose (fh);
 
-    value = strchr (type_instance, ',');
-    if (value == NULL)
-      continue;
-    *value = '\0';
-    value++;
+  if (waitpid (pl->pid, &status, 0) > 0)
+    pl->status = status;
 
-    DEBUG ("value = %s", value);
+  DEBUG ("exec plugin: Child %i exited with status %i.",
+      (int) pl->pid, pl->status);
 
-    if (strcasecmp ("counter", type) == 0)
-      submit_counter (type_instance, atoll (value));
-    else
-      submit_gauge (type_instance, atof (value));
-  } /* while (fgets) */
+  pl->pid = 0;
 
+  pthread_mutex_lock (&pl_lock);
+  pl->flags &= ~PL_RUNNING;
+  pthread_mutex_unlock (&pl_lock);
+
+  pthread_exit ((void *) 0);
+  return (NULL);
+} /* void *exec_read_one }}} */
+
+static void *exec_notification_one (void *arg) /* {{{ */
+{
+  program_list_t *pl = ((program_list_and_notification_t *) arg)->pl;
+  const notification_t *n = &((program_list_and_notification_t *) arg)->n;
+  int fd;
+  FILE *fh;
+  int pid;
+  int status;
+  const char *severity;
+
+  pid = fork_child (pl, &fd, NULL);
+  if (pid < 0) {
+    sfree (arg);
+    pthread_exit ((void *) 1);
+  }
+
+  fh = fdopen (fd, "w");
+  if (fh == NULL)
+  {
+    char errbuf[1024];
+    ERROR ("exec plugin: fdopen (%i) failed: %s", fd,
+	sstrerror (errno, errbuf, sizeof (errbuf)));
+    kill (pl->pid, SIGTERM);
+    pl->pid = 0;
+    close (fd);
+    sfree (arg);
+    pthread_exit ((void *) 1);
+  }
+
+  severity = "FAILURE";
+  if (n->severity == NOTIF_WARNING)
+    severity = "WARNING";
+  else if (n->severity == NOTIF_OKAY)
+    severity = "OKAY";
+
+  fprintf (fh,
+      "Severity: %s\n"
+      "Time: %u\n",
+      severity, (unsigned int) n->time);
+
+  /* Print the optional fields */
+  if (strlen (n->host) > 0)
+    fprintf (fh, "Host: %s\n", n->host);
+  if (strlen (n->plugin) > 0)
+    fprintf (fh, "Plugin: %s\n", n->plugin);
+  if (strlen (n->plugin_instance) > 0)
+    fprintf (fh, "PluginInstance: %s\n", n->plugin_instance);
+  if (strlen (n->type) > 0)
+    fprintf (fh, "Type: %s\n", n->type);
+  if (strlen (n->type_instance) > 0)
+    fprintf (fh, "TypeInstance: %s\n", n->type_instance);
+
+  fprintf (fh, "\n%s\n", n->message);
+
+  fflush (fh);
   fclose (fh);
-  pl->pid = 0;
 
+  waitpid (pid, &status, 0);
+
+  DEBUG ("exec plugin: Child %i exited with status %i.",
+      pid, status);
+
+  sfree (arg);
   pthread_exit ((void *) 0);
   return (NULL);
-} /* void *exec_read_one */
+} /* void *exec_notification_one }}} */
+
+static int exec_init (void) /* {{{ */
+{
+  struct sigaction sa;
+
+  memset (&sa, '\0', sizeof (sa));
+  sa.sa_handler = sigchld_handler;
+  sigaction (SIGCHLD, &sa, NULL);
+
+  return (0);
+} /* int exec_init }}} */
 
-static int exec_read (void)
+static int exec_read (void) /* {{{ */
 {
   program_list_t *pl;
 
@@ -347,18 +655,66 @@ static int exec_read (void)
     pthread_t t;
     pthread_attr_t attr;
 
-    if (pl->pid != 0)
+    /* Only execute `normal' style executables here. */
+    if ((pl->flags & PL_NORMAL) == 0)
       continue;
 
+    pthread_mutex_lock (&pl_lock);
+    /* Skip if a child is already running. */
+    if ((pl->flags & PL_RUNNING) != 0)
+    {
+      pthread_mutex_unlock (&pl_lock);
+      continue;
+    }
+    pl->flags |= PL_RUNNING;
+    pthread_mutex_unlock (&pl_lock);
+
     pthread_attr_init (&attr);
     pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
     pthread_create (&t, &attr, exec_read_one, (void *) pl);
   } /* for (pl) */
 
   return (0);
-} /* int exec_read */
+} /* int exec_read }}} */
 
-static int exec_shutdown (void)
+static int exec_notification (const notification_t *n)
+{
+  program_list_t *pl;
+  program_list_and_notification_t *pln;
+
+  for (pl = pl_head; pl != NULL; pl = pl->next)
+  {
+    pthread_t t;
+    pthread_attr_t attr;
+
+    /* Only execute `notification' style executables here. */
+    if ((pl->flags & PL_NOTIF_ACTION) == 0)
+      continue;
+
+    /* Skip if a child is already running. */
+    if (pl->pid != 0)
+      continue;
+
+    pln = (program_list_and_notification_t *) malloc (sizeof
+	(program_list_and_notification_t));
+    if (pln == NULL)
+    {
+      ERROR ("exec plugin: malloc failed.");
+      continue;
+    }
+
+    pln->pl = pl;
+    memcpy (&pln->n, n, sizeof (notification_t));
+
+    pthread_attr_init (&attr);
+    pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
+    pthread_create (&t, &attr, exec_notification_one, (void *) pln);
+  } /* for (pl) */
+
+  return (0);
+} /* int exec_notification */
+
+static int exec_shutdown (void) /* {{{ */
 {
   program_list_t *pl;
   program_list_t *next;
@@ -382,24 +738,17 @@ static int exec_shutdown (void)
   pl_head = NULL;
 
   return (0);
-} /* int exec_shutdown */
+} /* int exec_shutdown }}} */
 
-void module_register (modreg_e load)
+void module_register (void)
 {
-  if (load & MR_DATASETS)
-  {
-    plugin_register_data_set (&ds_counter);
-    plugin_register_data_set (&ds_gauge);
-  }
-
-  if (load & MR_READ)
-  {
-    plugin_register_config ("exec", exec_config, config_keys, config_keys_num);
-    plugin_register_read ("exec", exec_read);
-    plugin_register_shutdown ("exec", exec_shutdown);
-  }
+  plugin_register_complex_config ("exec", exec_config);
+  plugin_register_init ("exec", exec_init);
+  plugin_register_read ("exec", exec_read);
+  plugin_register_notification ("exec", exec_notification);
+  plugin_register_shutdown ("exec", exec_shutdown);
 } /* void module_register */
 
 /*
- * vim:shiftwidth=2:softtabstop=2:tabstop=8
+ * vim:shiftwidth=2:softtabstop=2:tabstop=8:fdm=marker
  */