lib/configs: refactor directory list merging

The original implementation used complex nested loops to merge
configuration file lists from different directories. This commit
simplifies the code by introducing a new config_merge_list()
function that handles the merging logic.

Changes:
- Add config_merge_list() to merge lists with duplicate detection
- Add config_cmp() comparison function using strcoll() (consistent
  with alphasort() behavior from scandirat())
- Add configs_add_filename() helper to reduce code duplication
- Simplify ul_configs_file_list() by replacing ~120 lines of
  merging logic with 3 calls to config_merge_list()
- Remove intermediate etc_run_file_list, merge directly to output
- Update read_dir() to return 0/-ENOMEM instead of entry count
- Use list_count_entries() to get final count

The new config_merge_list() moves entries directly from source
lists to the destination list without extra allocations, making
it more efficient than the previous approach.

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/lib/configs.c b/lib/configs.c
index 0b800d2d07107de132e58dd0d608d846f913bdb1..07576d2f0aa96345781c95cc81937f6e6c143363 100644 (file)
--- a/lib/configs.c
+++ b/lib/configs.c
@@ -96,6 +96,18 @@ static struct file_element *new_list_entry(const char *filename)
        return file_element;
 }
 
+static int configs_add_filename(struct list_head *list, const char *filename)
+{
+       struct file_element *e;
+
+       e = new_list_entry(filename);
+       if (e == NULL)
+               return -ENOMEM;
+
+       list_add_tail(&e->file_list, list);
+       return 0;
+}
+
 #if defined(HAVE_SCANDIRAT) && defined(HAVE_OPENAT)
 
 static int filter(const struct dirent *d)
@@ -120,9 +132,8 @@ static int read_dir(struct list_head *file_list,
        char *dirname = NULL;
        char *filename = NULL;
        int dd = -1, nfiles = 0, i;
-       int counter = 0;
+       int ret = 0;
        struct dirent **namelist = NULL;
-       struct file_element *entry = NULL;
 
        if (config_suffix)
                dirname = config_mk_path(S_IFDIR, "%s/%s/%s.%s.d",
@@ -152,18 +163,14 @@ static int read_dir(struct list_head *file_list,
                }
 
                if (asprintf(&filename, "%s/%s", dirname, d->d_name) < 0) {
-                       counter = -ENOMEM;
+                       ret = -ENOMEM;
                        break;
                }
-               entry = new_list_entry(filename);
+
+               ret = configs_add_filename(file_list, filename);
                free(filename);
-               if (entry == NULL) {
-                       counter = -ENOMEM;
+               if (ret < 0)
                        break;
-               }
-
-               list_add_tail(&entry->file_list, file_list);
-               counter++;
        }
 
 finish:
@@ -173,17 +180,58 @@ finish:
        free(dirname);
        if (dd >= 0)
                close(dd);
-       return counter;
+       return ret;
 }
 
 #endif /* HAVE_SCANDIRAT */
 
+static int config_cmp(struct list_head *a, struct list_head *b,
+                     void *data __attribute__((__unused__)))
+{
+       struct file_element *ea = list_entry(a, struct file_element, file_list);
+       struct file_element *eb = list_entry(b, struct file_element, file_list);
+       char *na = ul_basename(ea->filename);
+       char *nb = ul_basename(eb->filename);
+
+       return strcoll(na, nb);
+}
+
 static void free_list_entry(struct file_element *element)
 {
        free(element->filename);
        free(element);
 }
 
+static int config_merge_list(struct list_head *main_list,
+                             struct list_head *new_list)
+{
+       struct list_head *n, *m, *next;
+
+       list_for_each_safe(n, next, new_list) {
+               struct file_element *ne = list_entry(n, struct file_element, file_list);
+               char *nn = ul_basename(ne->filename);
+               int duplicate = 0;
+
+               list_for_each(m, main_list) {
+                       struct file_element *me = list_entry(m, struct file_element, file_list);
+                       char *mn = ul_basename(me->filename);
+
+                       if (strcoll(mn, nn) == 0) {
+                               duplicate = 1;
+                               break;
+                       }
+               }
+
+               if (!duplicate) {
+                       list_del_init(n);
+                       list_add_tail(n, main_list);
+               }
+       }
+
+       list_sort(main_list, config_cmp, NULL);
+       return 0;
+}
+
 int ul_configs_file_list(struct list_head *file_list,
                         const char *project,
                         const char *etc_subdir,
@@ -192,22 +240,17 @@ int ul_configs_file_list(struct list_head *file_list,
                         const char *config_name,
                         const char *config_suffix)
 {
-       char *filename = NULL, *run_basename = NULL, *usr_basename = NULL,
-               *etc_basename = NULL, *etc_run_basename = NULL;
+       char *main_file = NULL;
        struct list_head etc_file_list;
        struct list_head run_file_list;
-       struct list_head etc_run_file_list;
        struct list_head usr_file_list;
-       struct list_head *etc_entry = NULL, *usr_entry = NULL, *run_entry = NULL, *etc_run_entry = NULL;
-       struct file_element *add_element = NULL, *usr_element = NULL,
-               *run_element = NULL, *etc_element = NULL, *etc_run_element = NULL;
        int counter = 0;
+       int ret;
 
        INIT_LIST_HEAD(file_list);
 
-       if (!config_name){
+       if (!config_name)
                return -ENOTEMPTY;
-       }
 
        /* Default is /etc */
        if (!etc_subdir)
@@ -220,145 +263,65 @@ int ul_configs_file_list(struct list_head *file_list,
        if (!project)
                project = "";
 
-       /* Evaluating first "main" file which has to be parsed */
-       /* in the following order : /etc /run /usr             */
-       filename = main_configs(etc_subdir, project, config_name, config_suffix);
-       if (filename == NULL)
-               filename = main_configs(run_subdir, project, config_name, config_suffix);
-       if (filename == NULL)
-               filename = main_configs(usr_subdir, project, config_name, config_suffix);
-       if (filename != NULL) {
-               add_element = new_list_entry(filename);
-               free(filename);
-               if (add_element == NULL)
-                       return -ENOMEM;
-               list_add_tail(&add_element->file_list, file_list);
-               counter++;
-       }
+       /* Find "main" config file (but don't add to list yet) */
+       /* Search order: /etc /run /usr */
+       main_file = main_configs(etc_subdir, project, config_name, config_suffix);
+       if (main_file == NULL)
+               main_file = main_configs(run_subdir, project, config_name, config_suffix);
+       if (main_file == NULL)
+               main_file = main_configs(usr_subdir, project, config_name, config_suffix);
 
        INIT_LIST_HEAD(&etc_file_list);
        INIT_LIST_HEAD(&run_file_list);
-       INIT_LIST_HEAD(&etc_run_file_list);
        INIT_LIST_HEAD(&usr_file_list);
 
 #if defined(HAVE_SCANDIRAT) && defined(HAVE_OPENAT)
-       int ret_usr = 0, ret_etc = 0, ret_run = 0;
-        ret_etc = read_dir(&etc_file_list,
-                          project,
-                          etc_subdir,
-                          config_name,
-                          config_suffix);
-       ret_run = read_dir(&run_file_list,
-                          project,
-                          run_subdir,
-                          config_name,
-                          config_suffix);
-       ret_usr = read_dir(&usr_file_list,
-                          project,
-                          usr_subdir,
-                          config_name,
-                          config_suffix);
-       if (ret_etc == -ENOMEM || ret_usr == -ENOMEM || ret_run == -ENOMEM) {
-               counter = -ENOMEM;
+       ret = read_dir(&etc_file_list, project, etc_subdir, config_name, config_suffix);
+       if (ret == -ENOMEM)
                goto finish;
-       }
-#endif
 
-       /* Merging run and etc list in the correct order. Output: etc_run_list */
-       list_for_each(etc_entry, &etc_file_list) {
+       ret = read_dir(&run_file_list, project, run_subdir, config_name, config_suffix);
+       if (ret == -ENOMEM)
+               goto finish;
 
-               etc_element = list_entry(etc_entry, struct file_element, file_list);
-               etc_basename = ul_basename(etc_element->filename);
+       ret = read_dir(&usr_file_list, project, usr_subdir, config_name, config_suffix);
+       if (ret == -ENOMEM)
+               goto finish;
+#endif
 
-               list_for_each(run_entry, &run_file_list) {
+       /* Merge drop-in directories in priority order (high to low) */
+       ret = config_merge_list(file_list, &etc_file_list);
+       if (ret < 0)
+               goto finish;
 
-                       run_element = list_entry(run_entry, struct file_element, file_list);
-                       run_basename = ul_basename(run_element->filename);
+       ret = config_merge_list(file_list, &run_file_list);
+       if (ret < 0)
+               goto finish;
 
-                       if (strcmp(run_basename, etc_basename) <= 0) {
-                               if (strcmp(run_basename, etc_basename) < 0) {
-                                       add_element = new_list_entry(run_element->filename);
-                                       if (add_element == NULL) {
-                                               counter = -ENOMEM;
-                                               goto finish;
-                                       }
-                                       list_add_tail(&add_element->file_list, &etc_run_file_list);
-                               }
-                               list_del(&run_element->file_list);
-                       } else {
-                               break;
-                       }
-               }
-               add_element = new_list_entry(etc_element->filename);
-               if (add_element == NULL) {
-                       counter = -ENOMEM;
-                       goto finish;
-               }
-               list_add_tail(&add_element->file_list, &etc_run_file_list);
-       }
+       ret = config_merge_list(file_list, &usr_file_list);
+       if (ret < 0)
+               goto finish;
 
-       /* taking the rest of /run */
-       list_for_each(run_entry, &run_file_list) {
-               run_element = list_entry(run_entry, struct file_element, file_list);
-               add_element = new_list_entry(run_element->filename);
-               if (add_element == NULL) {
-                       counter = -ENOMEM;
-                       goto finish;
-               }
-               list_add_tail(&add_element->file_list, &etc_run_file_list);
-       }
+       /* Add main config file at the beginning (highest priority) */
+       if (main_file != NULL) {
+               struct list_head *e;
 
-       /* Merging etc_run list and var list in the correct order. Output: file_list
-          which will be returned. */
-       list_for_each(etc_run_entry, &etc_run_file_list) {
-
-               etc_run_element = list_entry(etc_run_entry, struct file_element, file_list);
-               etc_run_basename = ul_basename(etc_run_element->filename);
-
-               list_for_each(usr_entry, &usr_file_list) {
-
-                       usr_element = list_entry(usr_entry, struct file_element, file_list);
-                       usr_basename = ul_basename(usr_element->filename);
-
-                       if (strcmp(usr_basename, etc_run_basename) <= 0) {
-                               if (strcmp(usr_basename, etc_run_basename) < 0) {
-                                       add_element = new_list_entry(usr_element->filename);
-                                       if (add_element == NULL) {
-                                               counter = -ENOMEM;
-                                               goto finish;
-                                       }
-                                       list_add_tail(&add_element->file_list, file_list);
-                                       counter++;
-                               }
-                               list_del(&usr_element->file_list);
-                       } else {
-                               break;
-                       }
-               }
-               add_element = new_list_entry(etc_run_element->filename);
-               if (add_element == NULL) {
-                       counter = -ENOMEM;
+               ret = configs_add_filename(file_list, main_file);
+               free(main_file);
+               if (ret < 0)
                        goto finish;
-               }
-               list_add_tail(&add_element->file_list, file_list);
-               counter++;
-       }
 
-       /* taking the rest of /usr */
-       list_for_each(usr_entry, &usr_file_list) {
-               usr_element = list_entry(usr_entry, struct file_element, file_list);
-               add_element = new_list_entry(usr_element->filename);
-               if (add_element == NULL) {
-                       counter = -ENOMEM;
-                       goto finish;
-               }
-               list_add_tail(&add_element->file_list, file_list);
-               counter++;
+               /* Move last element (just added) to front */
+               e = file_list->prev;
+               list_del(e);
+               list_add(e, file_list);
        }
 
+       counter = list_count_entries(file_list);
+
 finish:
        ul_configs_free_list(&etc_file_list);
-       ul_configs_free_list(&etc_run_file_list);
+       ul_configs_free_list(&run_file_list);
        ul_configs_free_list(&usr_file_list);
 
        return counter;