config.c: loading templates from multiple files into one template table

This patch implements loading files from /etc/cgconfig.d/. It uses already implemented functions. To hold list of files to be read for template reloading, new static variable for this list (list of template files) has been added to config.c. It is the same list as file list read with cgconfigparser (cgconfig.c file), i.e. the same functions are called. Because parser reads only one file, it is called for each file in template file list. Thus initialization, resp. template duplication has to be called before, resp. after each file parsing. Thus new functions has been presented, thus modifying config.[h|c] api and libcgroup.map. Again parsing more files for templates is analogy to parsing files for groups in cgconfig.c.

cgroup_load_cached_templates_from_file is a modification of cgroup_reload_cached_templates and cgroup_init_templates_cache. Only for loop and auxiliary variables added.

Changelog:
        Description of config.h updated. [init|reload] replaced by load
        TEMPLATE_ACTION_[INIT|RELOAD] removed
        Instead of returning error on uninitialized list of template files, CGCONFIG_CONF_FILE with old cgroup_[init|reload]_templates_cache functions is called.
        cgroup_config_create_template_group reports which template file caused unsuccesfull loading of template files

Signed-off-by: Jan Chaloupka <jchaloup@redhat.com>
Acked-by: Ivana Hutarova Varekova <varekova@redhat.com>

diff --git a/include/libcgroup/config.h b/include/libcgroup/config.h
index 43568e1cf8d06b2d6ad81dc21effac3cd0ce60f5..9aaa39032a8bf8e6e9b862e4b5def32b098311b4 100644 (file)
--- a/include/libcgroup/config.h
+++ b/include/libcgroup/config.h
@@ -83,12 +83,33 @@ int cgroup_init_templates_cache(char *pathname);
  */
 int cgroup_reload_cached_templates(char *pathname);
 
+/**
+ * Load the templates cache from files. Before calling this function,
+ * cgroup_templates_cache_set_source_files has to be called first.
+ * @param file_index index of file which was unable to be parsed
+ * @return 0 on success, > 0 on error
+ */
+int cgroup_load_templates_cache_from_files(int *file_index);
+
+/**
+ * Setting source files of templates. This function has to be called before
+ * any call of cgroup_load_templates_cache_from_files.
+ * @param tmpl_files
+ */
+struct cgroup_string_list;
+void cgroup_templates_cache_set_source_files(
+       struct cgroup_string_list *tmpl_files);
+
 /**
  * Physically create a new control group in kernel, based on given control
  * group template and configuration file. If given template is not set in
  * configuration file, then the procedure works create the control group
  * using  cgroup_create_cgroup() function
  *
+ * Templates are loaded using cgroup_load_templates_cache_from_files
+ * function, which must be preceded by cgroup_templates_cache_set_source_files
+ * call.
+ *
  * The flags can alter the behavior of this function:
  * CGFLAG_USE_TEMPLATE_CACHE: Use cached templates instead of
  * parsing the config file

diff --git a/src/config.c b/src/config.c
index da2c0dd024ab078a43417b4dd1a440516818d1c1..a576001f3b090f0b9e7fc9b855282e9b0ed69f70 100644 (file)
--- a/src/config.c
+++ b/src/config.c
@@ -41,6 +41,8 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 
+#include "tools/tools-common.h"
+
 unsigned int MAX_CGROUPS = 64; /* NOTE: This value changes dynamically */
 unsigned int MAX_TEMPLATES = 64;
                                /* NOTE: This value changes dynamically */
@@ -89,6 +91,7 @@ static int config_template_table_index;
  */
 static struct cgroup *template_table;
 static int template_table_index;
+static struct cgroup_string_list *template_files;
 
 
 /*
@@ -1572,6 +1575,161 @@ int cgroup_init_templates_cache(char *pathname)
 
 }
 
+/**
+ * Setting source files of templates. This function has to be called before
+ * any call of cgroup_load_templates_cache_from_files.
+ * @param tmpl_files
+ */
+void cgroup_templates_cache_set_source_files(
+       struct cgroup_string_list *tmpl_files)
+{
+       template_files = tmpl_files;
+}
+
+/**
+ * Appending cgroup templates parsed by parser to template_table
+ * @param offset number of templates already in the table
+ */
+int cgroup_add_cgroup_templates(int offset)
+{
+       int i, ti, ret;
+
+       for (i = 0; i < config_template_table_index; i++) {
+               ti = i + offset;
+               ret = cgroup_copy_cgroup(&template_table[ti],
+                       &config_template_table[i]);
+               if (ret)
+                       return ret;
+
+               strcpy((template_table[ti]).name,
+                       (config_template_table[i]).name);
+               template_table[ti].tasks_uid =
+                       config_template_table[i].tasks_uid;
+               template_table[ti].tasks_gid =
+                       config_template_table[i].tasks_gid;
+               template_table[ti].task_fperm =
+                       config_template_table[i].task_fperm;
+               template_table[ti].control_uid =
+                       config_template_table[i].control_uid;
+               template_table[ti].control_gid =
+                       config_template_table[i].control_gid;
+               template_table[ti].control_fperm =
+                       config_template_table[i].control_fperm;
+               template_table[ti].control_dperm =
+                       config_template_table[i].control_dperm;
+       }
+
+       return 0;
+}
+
+/**
+ * Expand template table based on new number of parsed templates, i.e.
+ * on value of config_template_table_index.
+ * Change value of template_table_index.
+ * @return 0 on success, < 0 on error
+ */
+int cgroup_expand_template_table(void)
+{
+       int i;
+
+       template_table = realloc(template_table,
+               (template_table_index + config_template_table_index)
+               *sizeof(struct cgroup));
+
+       if (template_table == NULL)
+               return -ECGOTHER;
+
+       for (i = 0; i < config_template_table_index; i++)
+               template_table[i + template_table_index].index = 0;
+
+       template_table_index += config_template_table_index;
+
+       return 0;
+}
+
+/**
+ * Load the templates cache from files. Before calling this function,
+ * cgroup_templates_cache_set_source_files has to be called first.
+ * @param file_index index of file which was unable to be parsed
+ * @return 0 on success, > 0 on error
+ */
+int cgroup_load_templates_cache_from_files(int *file_index)
+{
+       int ret;
+       int i, j;
+       int template_table_last_index;
+       char *pathname;
+
+       if (!template_files) {
+               /* source files has not been set */
+               cgroup_dbg("Template source files have not been set. ");
+               cgroup_dbg("Using only %s\n", CGCONFIG_CONF_FILE);
+
+               if (template_table_index == 0)
+                       /* the rules cache is empty */
+                       return cgroup_init_templates_cache(
+                               CGCONFIG_CONF_FILE);
+               else
+                       /* cache is not empty */
+                       return cgroup_reload_cached_templates(
+                               CGCONFIG_CONF_FILE);
+       }
+
+       if (template_table) {
+               /* template structures have to be free */
+               for (i = 0; i < template_table_index; i++)
+                       cgroup_free_controllers(&template_table[i]);
+               free(template_table);
+               template_table = NULL;
+       }
+       template_table_index = 0;
+
+       if ((config_template_table_index != 0) || (config_table_index != 0)) {
+               /* config structures have to be clean before parsing */
+               cgroup_free_config();
+       }
+
+       for (j = 0; j < template_files->count; j++) {
+               pathname = template_files->items[j];
+
+               cgroup_dbg("Parsing templates from %s.\n", pathname);
+               /* Attempt to read the configuration file
+                * and cache the rules. */
+               ret = cgroup_parse_config(pathname);
+               if (ret) {
+                       cgroup_dbg("Could not initialize rule cache, ");
+                       cgroup_dbg("error was: %d\n", ret);
+                       *file_index = j;
+                       return ret;
+               }
+
+               if (config_template_table_index > 0) {
+                       template_table_last_index = template_table_index;
+                       ret = cgroup_expand_template_table();
+                       if (ret) {
+                               cgroup_dbg("Could not expand template table, ");
+                               cgroup_dbg("error was: %d\n", -ret);
+                               *file_index = j;
+                               return -ret;
+                       }
+
+                       /* copy template data to templates cache structures */
+                       cgroup_dbg("Copying templates to template table ");
+                       cgroup_dbg("from %s.\n", pathname);
+                       ret = cgroup_add_cgroup_templates(
+                               template_table_last_index);
+                       if (ret) {
+                               cgroup_dbg("Unable to copy cgroup\n");
+                               *file_index = j;
+                               return ret;
+                       }
+                       cgroup_dbg("Templates to template table copied\n");
+               }
+       }
+
+       return 0;
+}
+
 /*
  * Create a given cgroup, based on template configuration if it is present
  * if the template is not present cgroup is creted using cgroup_create_cgroup
@@ -1593,13 +1751,22 @@ int cgroup_config_create_template_group(struct cgroup *cgroup,
         * use CGCONFIG_CONF_FILE by default
         */
        if (!(flags & CGFLAG_USE_TEMPLATE_CACHE)) {
-               if (template_table_index == 0)
-                       /* the rules cache is empty */
-                       ret = cgroup_init_templates_cache(CGCONFIG_CONF_FILE);
-               else
-                       /* cache is not empty */
-                       ret = cgroup_reload_cached_templates(
-                               CGCONFIG_CONF_FILE);
+               int fileindex;
+
+               /* the rules cache is empty */
+               ret = cgroup_load_templates_cache_from_files(
+                       &fileindex);
+               if (ret != 0) {
+                       if (fileindex < 0) {
+                               cgroup_dbg("Error: Template source files ");
+                               cgroup_dbg("have not been set\n");
+                       } else {
+                           cgroup_dbg("Error: Failed to load template");
+                           cgroup_dbg("rules from %s. ",
+                                   template_files->items[fileindex]);
+                       }
+               }
+
                if (ret != 0) {
                        cgroup_dbg("Failed initialize templates cache.\n");
                        return ret;

diff --git a/src/libcgroup.map b/src/libcgroup.map
index b0c162c2581c746d8a4f1caa8adca95b06c2f87a..f8b0fb966ce40e94510bf6a0aadadf4d91c4ca4e 100644 (file)
--- a/src/libcgroup.map
+++ b/src/libcgroup.map
@@ -117,3 +117,8 @@ CGROUP_0.39 {
        cgroup_log;
        cgroup_parse_log_level_str;
 } CGROUP_0.38;
+
+CGROUP_0.40 {
+       cgroup_templates_cache_set_source_files;
+       cgroup_load_templates_cache_from_files;
+} CGROUP_0.39;