filesystem.[ch]: Move filesystem accessing functions into a separate module.

[collection4.git] / filesystem.c

diff --git a/filesystem.c b/filesystem.c
new file mode 100644 (file)
index 0000000..ba57249
--- /dev/null
+++ b/filesystem.c
@@ -0,0 +1,299 @@
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <limits.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <dirent.h>
+
+#define DATA_DIR "/var/lib/collectd/rrd"
+
+#include "filesystem.h"
+
+struct fs_scan_dir_data_s /* {{{ */
+{
+  fs_ident_cb_t callback;
+  void *user_data;
+
+  char *host;
+  char *plugin;
+  char *plugin_instance;
+  char *type;
+  char *type_instance;
+}; /* }}} */
+typedef struct fs_scan_dir_data_s fs_scan_dir_data_t;
+
+typedef int (*callback_type_t)   (const char *type,   void *user_data);
+typedef int (*callback_plugin_t) (const char *plugin, void *user_data);
+typedef int (*callback_host_t)   (const char *host,   void *user_data);
+
+/*
+ * Directory and file walking functions
+ */
+static int foreach_rrd_file (const char *dir, /* {{{ */
+    int (*callback) (const char *, void *),
+    void *user_data)
+{
+  DIR *dh;
+  struct dirent *entry;
+  int status;
+
+  if (callback == NULL)
+    return (EINVAL);
+
+  dh = opendir (dir);
+  if (dh == NULL)
+    return (errno);
+
+  while ((entry = readdir (dh)) != NULL)
+  {
+    struct stat statbuf;
+    char abspath[PATH_MAX + 1];
+    size_t d_name_len;
+
+    if (entry->d_name[0] == '.')
+      continue;
+
+    d_name_len = strlen (entry->d_name);
+    if (d_name_len <= 4)
+      continue;
+
+    if (strcasecmp (".rrd", entry->d_name + (d_name_len - 4)) != 0)
+      continue;
+
+    snprintf (abspath, sizeof (abspath), "%s/%s", dir, entry->d_name);
+    abspath[sizeof (abspath) - 1] = 0;
+
+    memset (&statbuf, 0, sizeof (statbuf));
+
+    status = stat (abspath, &statbuf);
+    if (status != 0)
+      continue;
+
+    if (!S_ISREG (statbuf.st_mode))
+      continue;
+
+    entry->d_name[d_name_len - 4] = 0;
+
+    status = (*callback) (entry->d_name, user_data);
+    if (status != 0)
+      break;
+  } /* while (readdir) */
+
+  closedir (dh);
+  return (status);
+} /* }}} int foreach_rrd_file */
+
+static int foreach_dir (const char *dir, /* {{{ */
+    int (*callback) (const char *, void *),
+    void *user_data)
+{
+  DIR *dh;
+  struct dirent *entry;
+  int status;
+
+  if (callback == NULL)
+    return (EINVAL);
+
+  dh = opendir (dir);
+  if (dh == NULL)
+    return (errno);
+
+  while ((entry = readdir (dh)) != NULL)
+  {
+    struct stat statbuf;
+    char abspath[PATH_MAX + 1];
+
+    if (entry->d_name[0] == '.')
+      continue;
+
+    snprintf (abspath, sizeof (abspath), "%s/%s", dir, entry->d_name);
+    abspath[sizeof (abspath) - 1] = 0;
+
+    memset (&statbuf, 0, sizeof (statbuf));
+
+    status = stat (abspath, &statbuf);
+    if (status != 0)
+      continue;
+
+    if (!S_ISDIR (statbuf.st_mode))
+      continue;
+
+    status = (*callback) (entry->d_name, user_data);
+    if (status != 0)
+      break;
+  } /* while (readdir) */
+
+  closedir (dh);
+  return (status);
+} /* }}} int foreach_dir */
+
+static int foreach_type (const char *host, const char *plugin, /* {{{ */
+    callback_type_t callback, void *user_data)
+{
+  char abspath[PATH_MAX + 1];
+
+  if ((host == NULL) || (plugin == NULL))
+    return (EINVAL);
+
+  snprintf (abspath, sizeof (abspath), "%s/%s/%s", DATA_DIR, host, plugin);
+  abspath[sizeof (abspath) - 1] = 0;
+
+  return (foreach_rrd_file (abspath, callback, user_data));
+} /* }}} int foreach_type */
+
+static int foreach_plugin (const char *host, /* {{{ */
+    callback_plugin_t callback,
+    void *user_data)
+{
+  char abspath[PATH_MAX + 1];
+
+  if (host == NULL)
+    return (EINVAL);
+
+  snprintf (abspath, sizeof (abspath), "%s/%s", DATA_DIR, host);
+  abspath[sizeof (abspath) - 1] = 0;
+
+  return (foreach_dir (abspath, callback, user_data));
+} /* }}} int foreach_plugin */
+
+static int foreach_host (callback_host_t callback, /* {{{ */
+    void *user_data)
+{
+  return (foreach_dir (DATA_DIR, callback, user_data));
+} /* }}} int foreach_host */
+
+/*
+ * Functions building "fs_scan_dir_data_t" and calling the user-supplied
+ * callback eventually.
+ */
+static int scan_type (const char *type, void *user_data) /* {{{ */
+{
+  fs_scan_dir_data_t *data = user_data;
+  graph_ident_t *ident;
+  int status;
+
+  if ((type == NULL) || (data == NULL))
+    return (EINVAL);
+
+  if ((data->type != NULL) || (data->type_instance != NULL))
+    return (EINVAL);
+
+  data->type = strdup (type);
+  if (data->type == NULL)
+    return (ENOMEM);
+
+  data->type_instance = strchr (data->type, '-');
+  if (data->type_instance != NULL)
+  {
+    *data->type_instance = 0;
+    data->type_instance++;
+  }
+  else
+  {
+    data->type_instance = data->type + strlen (data->type);
+  }
+
+  ident = ident_create (data->host,
+      data->plugin, data->plugin_instance,
+      data->type, data->type_instance);
+  if (ident == NULL)
+  {
+    status = -1;
+  }
+  else
+  {
+    status = (*data->callback) (ident, data->user_data);
+    ident_destroy (ident);
+  }
+
+  free (data->type);
+  data->type = NULL;
+  data->type_instance = NULL;
+
+  return (status);
+} /* }}} int scan_type */
+
+static int scan_plugin (const char *plugin, void *user_data) /* {{{ */
+{
+  fs_scan_dir_data_t *data = user_data;
+  int status;
+
+  if ((plugin == NULL) || (data == NULL))
+    return (EINVAL);
+
+  if ((data->plugin != NULL) || (data->plugin_instance != NULL))
+    return (EINVAL);
+
+  data->plugin = strdup (plugin);
+  if (data->plugin == NULL)
+    return (ENOMEM);
+
+  data->plugin_instance = strchr (data->plugin, '-');
+  if (data->plugin_instance != NULL)
+  {
+    *data->plugin_instance = 0;
+    data->plugin_instance++;
+  }
+  else
+  {
+    data->plugin_instance = data->plugin + strlen (data->plugin);
+  }
+
+  status = foreach_type (data->host, plugin, scan_type, data);
+
+  free (data->plugin);
+  data->plugin = NULL;
+  data->plugin_instance = NULL;
+
+  return (status);
+} /* }}} int scan_plugin */
+
+static int scan_host (const char *host, void *user_data) /* {{{ */
+{
+  fs_scan_dir_data_t *data = user_data;
+  int status;
+
+  if ((host == NULL) || (data == NULL))
+    return (EINVAL);
+
+  if (data->host != NULL)
+    return (EINVAL);
+
+  data->host = strdup (host);
+  if (data->host == NULL)
+    return (ENOMEM);
+
+  status =  foreach_plugin (host, scan_plugin, data);
+
+  free (data->host);
+  data->host = NULL;
+
+  return (status);
+} /* }}} int scan_host */
+
+/*
+ * Public function
+ */
+int fs_scan (fs_ident_cb_t callback, void *user_data) /* {{{ */
+{
+  fs_scan_dir_data_t data;
+
+  memset (&data, 0, sizeof (data));
+  data.callback = callback;
+  data.user_data = user_data;
+
+  data.host = NULL;
+  data.plugin = NULL;
+  data.plugin_instance = NULL;
+  data.type = NULL;
+  data.type_instance = NULL;
+
+  foreach_host (scan_host, &data);
+
+  return (0);
+} /* }}} int fs_scan */
+
+/* vim: set sw=2 sts=2 et fdm=marker : */