libcgroup: Added simple structure for list of strings.

As preparation for next patches, simple list of strings is added to
tools-common.[ch]. It will be used as list of config files later.

Signed-off-by: Jan Safranek <jsafrane@redhat.com>

diff --git a/src/tools/tools-common.c b/src/tools/tools-common.c
index 7d633be404ae542383e214b0c45b7a72d68ec1aa..729b00c002d0e14ac7b2074f445913d61d3cb28a 100644 (file)
--- a/src/tools/tools-common.c
+++ b/src/tools/tools-common.c
@@ -14,10 +14,15 @@
  *
  */
 
+/* for asprintf */
+#define _GNU_SOURCE
+
 #include <errno.h>
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
+#include <sys/types.h>
+#include <dirent.h>
 
 #include <libcgroup.h>
 #include "tools-common.h"
@@ -114,3 +119,117 @@ void cgroup_free_group_spec(struct cgroup_group_spec *cl)
 }
 
 
+int cgroup_string_list_init(struct cgroup_string_list *list,
+               int initial_size)
+{
+       if (list == NULL)
+               return ECGINVAL;
+       list->items = calloc(initial_size, sizeof(char *));
+       if (!list->items)
+               return ECGFAIL;
+       list->count = 0;
+       list->size = initial_size;
+       return 0;
+}
+
+void cgroup_string_list_free(struct cgroup_string_list *list)
+{
+       int i;
+
+       if (list == NULL)
+               return;
+
+       if (list->items == NULL)
+               return;
+
+       for (i = 0; i < list->count; i++)
+               free(list->items[i]);
+
+       free(list->items);
+}
+
+int cgroup_string_list_add_item(struct cgroup_string_list *list,
+               const char *item)
+{
+       if (list == NULL)
+               return ECGINVAL;
+       if (list->size <= list->count) {
+               char **tmp = realloc(list->items,
+                               sizeof(char *) * list->size*2);
+               if (tmp == NULL)
+                       return ECGFAIL;
+               list->items = tmp;
+               list->size = list->size * 2;
+       }
+
+       list->items[list->count] = strdup(item);
+       if (list->items[list->count] == NULL)
+               return ECGFAIL;
+       list->count++;
+       return 0;
+}
+
+static int _compare_string(const void *a, const void *b)
+{
+       const char *sa = * (char * const *) a;
+       const char *sb = * (char * const *) b;
+       return strcmp(sa, sb);
+}
+
+
+int cgroup_string_list_add_directory(struct cgroup_string_list *list,
+               char *dirname, char *program_name)
+{
+       int start, ret, count = 0;
+       DIR *d;
+       struct dirent *item;
+
+       if (list == NULL)
+               return ECGINVAL;
+
+       start = list->count;
+
+       d = opendir(dirname);
+       if (!d) {
+               fprintf(stderr, "%s: cannot open %s: %s\n", program_name,
+                               dirname, strerror(errno));
+               exit(1);
+       }
+
+       do {
+               errno = 0;
+               item = readdir(d);
+               if (item && (item->d_type == DT_REG
+                               || item->d_type == DT_LNK)) {
+                       char *tmp;
+                       ret = asprintf(&tmp, "%s/%s", dirname, item->d_name);
+                       if (ret < 0) {
+                               fprintf(stderr, "%s: out of memory\n",
+                                               program_name);
+                               exit(1);
+                       }
+                       ret = cgroup_string_list_add_item(list, tmp);
+                       free(tmp);
+                       count++;
+                       if (ret) {
+                               fprintf(stderr, "%s: %s\n",
+                                               program_name,
+                                               cgroup_strerror(ret));
+                               exit(1);
+                       }
+               }
+               if (!item && errno) {
+                       fprintf(stderr, "%s: cannot read %s: %s\n",
+                                       program_name, dirname, strerror(errno));
+                       exit(1);
+               }
+       } while (item != NULL);
+       closedir(d);
+
+       /* sort the names found in the directory */
+       if (count > 0)
+               qsort(&list->items[start], count, sizeof(char *),
+                               _compare_string);
+       return 0;
+}
+

diff --git a/src/tools/tools-common.h b/src/tools/tools-common.h
index b261dc326d2047f08b439f4cc37f6ca0de1bf801..199444d3ff9670bc4b44b895d8ae0037ed0b40e5 100644 (file)
--- a/src/tools/tools-common.h
+++ b/src/tools/tools-common.h
@@ -37,6 +37,15 @@ struct cgroup_group_spec {
 };
 
 
+/**
+ * Simple dynamic array of strings.
+ */
+struct cgroup_string_list {
+       char **items;
+       int size;
+       int count;
+};
+
 /**
  * Parse command line option with group specifier into provided data structure.
  * The option must have form of 'controller1,controller2,..:group_name'.
@@ -59,4 +68,41 @@ int parse_cgroup_spec(struct cgroup_group_spec **cdptr, char *optarg,
  */
 void cgroup_free_group_spec(struct cgroup_group_spec *cl);
 
+
+/**
+ * Initialize a new list.
+ * @param list List to initialize.
+ * @param initial_size Initial size of the list to pre-allocate.
+ */
+int cgroup_string_list_init(struct cgroup_string_list *list,
+               int initial_size);
+
+/**
+ * Destroy a list, automatically freeing all its items.
+ * @param list List to destroy.
+ */
+void cgroup_string_list_free(struct cgroup_string_list *list);
+
+/**
+ * Adds new item to the list. It automatically resizes underlying array if
+ * needed.
+ * @param list List to modify.
+ * @param item Item to add. The item is automatically copied to new buffer.
+ */
+int cgroup_string_list_add_item(struct cgroup_string_list *list,
+               const char *item);
+
+/**
+ * Add alphabetically sorted files present in given directory (without subdirs)
+ * to list of strings. The function exits on error.
+ * @param list The list to add files to.
+ * @param dirname Full path to directory to examime.
+ * @param program_name Name of the executable, it will be used for printing
+ * errors to stderr.
+ *
+ */
+int cgroup_string_list_add_directory(struct cgroup_string_list *list,
+               char *dirname, char *program_name);
+
+
 #endif /* TOOLS_COMMON */