ucm: top-level path - set directory from symlink

It is useful to read the top-level symlink and set the configuration
directory according this symlink for the relative paths.

Signed-off-by: Jaroslav Kysela <perex@perex.cz>

diff --git a/src/ucm/parser.c b/src/ucm/parser.c
index 487900574e5caf2c526f0f6dfe123e9468f9c989..7bdaa8fe7b1bde36292fd8b563f9cfba9fa000c5 100644 (file)
--- a/src/ucm/parser.c
+++ b/src/ucm/parser.c
@@ -31,6 +31,7 @@
  */
 
 #include "ucm_local.h"
+#include <sys/stat.h>
 #include <stdbool.h>
 #include <dirent.h>
 #include <limits.h>
@@ -2186,6 +2187,7 @@ static int parse_toplevel_path(snd_use_case_mgr_t *uc_mgr,
        snd_config_t *n, *n2;
        const char *id;
        char *dir = NULL, *file = NULL, fn[PATH_MAX];
+       struct stat st;
        long version;
        int err;
 
@@ -2260,23 +2262,51 @@ static int parse_toplevel_path(snd_use_case_mgr_t *uc_mgr,
                }
 
                ucm_filename(fn, sizeof(fn), version, dir, file);
-               if (access(fn, R_OK) == 0) {
-                       if (replace_string(&uc_mgr->conf_dir_name, dir) == NULL) {
-                               err = -ENOMEM;
-                               goto __error;
-                       }
-                       if (replace_string(&uc_mgr->conf_file_name, file) == NULL) {
-                               err = -ENOMEM;
-                               goto __error;
+               if (access(fn, R_OK) == 0 && lstat(fn, &st) == 0) {
+                       if (st.st_mode & S_IFLNK) {
+                               ssize_t r;
+                               char *link, *dir2, *p;
+
+                               link = malloc(PATH_MAX);
+                               if (link == NULL)
+                                       goto __enomem;
+                               r = readlink(fn, link, PATH_MAX - 1);
+                               if (r <= 0) {
+                                       free(link);
+                                       goto __next;
+                               }
+                               link[r] = '\0';
+                               p = strrchr(link, '/');
+                               if (p) {
+                                       *p = '\0';
+                                       dir2 = malloc(PATH_MAX);
+                                       if (dir2 == NULL) {
+                                               free(link);
+                                               goto __enomem;
+                                       }
+                                       strncpy(dir2, dir, PATH_MAX - 1);
+                                       strncat(dir2, "/", PATH_MAX - 1);
+                                       strncat(dir2, link, PATH_MAX - 1);
+                                       fn[PATH_MAX - 1] = '\0';
+                                       free(dir);
+                                       dir = dir2;
+                               }
+                               free(link);
                        }
+                       if (replace_string(&uc_mgr->conf_dir_name, dir) == NULL)
+                               goto __enomem;
+                       if (replace_string(&uc_mgr->conf_file_name, file) == NULL)
+                               goto __enomem;
                        strncpy(filename, fn, PATH_MAX);
+                       filename[PATH_MAX - 1] = '\0';
                        uc_mgr->conf_format = version;
                        goto __ok;
                }
 
 __next:
                free(file);
-               free(dir);
+               if (dir != fn)
+                       free(dir);
                dir = NULL;
                file = NULL;
        }
@@ -2284,11 +2314,16 @@ __next:
        err = -ENOENT;
        goto __error;
 
+__enomem:
+       err = -ENOMEM;
+       goto __error;
+
 __ok:
        err = 0;
 __error:
        free(file);
-       free(dir);
+       if (dir != fn)
+               free(dir);
        return err;
 }