libudev: update documentation

[elogind.git] / libudev / libudev-enumerate.c

diff --git a/libudev/libudev-enumerate.c b/libudev/libudev-enumerate.c
index 96cf0609073dd283695338c76219d3aff61b3f4a..9a61a61f0d4a44d32ca78717b0c2d0c2d5766f54 100644 (file)
--- a/libudev/libudev-enumerate.c
+++ b/libudev/libudev-enumerate.c
@@ -190,7 +190,8 @@ static int syspath_cmp(const void *p1, const void *p2)
        return ret;
 }
 
-static int devices_delay(struct udev *udev, const char *syspath)
+/* For devices that should be moved to the absolute end of the list */
+static int devices_delay_end(struct udev *udev, const char *syspath)
 {
        static const char *delay_device_list[] = {
                "/block/md",
@@ -210,6 +211,32 @@ static int devices_delay(struct udev *udev, const char *syspath)
        return 0;
 }
 
+/* For devices that should just be moved a little bit later, just
+ * before the point where some common path prefix changes. Returns the
+ * number of characters that make up that common prefix */
+static size_t devices_delay_later(struct udev *udev, const char *syspath)
+{
+       const char *c;
+
+       /* For sound cards the control device must be enumerated last
+        * to make sure it's the final device node that gets ACLs
+        * applied. Applications rely on this fact and use ACL changes
+        * on the control node as an indicator that the ACL change of
+        * the entire sound card completed. The kernel makes this
+        * guarantee when creating those devices, and hence we should
+        * too when enumerating them. */
+
+       if ((c = strstr(syspath, "/sound/card"))) {
+               c += 11;
+               c += strcspn(c, "/");
+
+               if (strncmp(c, "/controlC", 9) == 0)
+                       return c - syspath + 1;
+       }
+
+       return 0;
+}
+
 /**
  * udev_enumerate_get_list_entry:
  * @udev_enumerate: context
@@ -223,7 +250,8 @@ struct udev_list_entry *udev_enumerate_get_list_entry(struct udev_enumerate *ude
        if (!udev_enumerate->devices_uptodate) {
                unsigned int i;
                unsigned int max;
-               struct syspath *prev = NULL;
+               struct syspath *prev = NULL, *move_later = NULL;
+               size_t move_later_prefix = 0;
 
                udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->devices_list);
                qsort(udev_enumerate->devices, udev_enumerate->devices_cur, sizeof(struct syspath), syspath_cmp);
@@ -240,14 +268,39 @@ struct udev_list_entry *udev_enumerate_get_list_entry(struct udev_enumerate *ude
                        prev = entry;
 
                        /* skip to be delayed devices, and add them to the end of the list */
-                       if (devices_delay(udev_enumerate->udev, entry->syspath)) {
+                       if (devices_delay_end(udev_enumerate->udev, entry->syspath)) {
                                syspath_add(udev_enumerate, entry->syspath);
                                continue;
                        }
 
+                       /* skip to be delayed devices, and move the to
+                        * the point where the prefix changes. We can
+                        * only move one item at a time. */
+                       if (!move_later) {
+                               move_later_prefix = devices_delay_later(udev_enumerate->udev, entry->syspath);
+
+                               if (move_later_prefix > 0) {
+                                       move_later = entry;
+                                       continue;
+                               }
+                       }
+
+                       if (move_later &&
+                           strncmp(entry->syspath, move_later->syspath, move_later_prefix) != 0) {
+
+                               udev_list_entry_add(udev_enumerate->udev, &udev_enumerate->devices_list,
+                                           move_later->syspath, NULL, 0, 0);
+                               move_later = NULL;
+                       }
+
                        udev_list_entry_add(udev_enumerate->udev, &udev_enumerate->devices_list,
                                            entry->syspath, NULL, 0, 0);
                }
+
+               if (move_later)
+                       udev_list_entry_add(udev_enumerate->udev, &udev_enumerate->devices_list,
+                                           move_later->syspath, NULL, 0, 0);
+
                /* add and cleanup delayed devices from end of list */
                for (i = max; i < udev_enumerate->devices_cur; i++) {
                        struct syspath *entry = &udev_enumerate->devices[i];
@@ -506,7 +559,7 @@ static int scan_dir_and_add_devices(struct udev_enumerate *udev_enumerate,
        if (subdir1 != NULL)
                l = util_strpcpyl(&s, l, "/", subdir1, NULL);
        if (subdir2 != NULL)
-               l = util_strpcpyl(&s, l, "/", subdir2, NULL);
+               util_strpcpyl(&s, l, "/", subdir2, NULL);
        dir = opendir(path);
        if (dir == NULL)
                return -1;
@@ -521,6 +574,8 @@ static int scan_dir_and_add_devices(struct udev_enumerate *udev_enumerate,
                        continue;
 
                util_strscpyl(syspath, sizeof(syspath), path, "/", dent->d_name, NULL);
+               if (!match_property(udev_enumerate, syspath))
+                       continue;
                if (lstat(syspath, &statbuf) != 0)
                        continue;
                if (S_ISREG(statbuf.st_mode))
@@ -533,8 +588,6 @@ static int scan_dir_and_add_devices(struct udev_enumerate *udev_enumerate,
                        continue;
                if (!match_sysattr(udev_enumerate, syspath))
                        continue;
-               if (!match_property(udev_enumerate, syspath))
-                       continue;
                syspath_add(udev_enumerate, syspath);
        }
        closedir(dir);
@@ -632,18 +685,6 @@ int udev_enumerate_scan_devices(struct udev_enumerate *udev_enumerate)
                scan_dir(udev_enumerate, "bus", "devices", NULL);
                dbg(udev, "searching '/class/*' dir\n");
                scan_dir(udev_enumerate, "class", NULL, NULL);
-               /* if block isn't a class, scan /block/ */
-               util_strscpyl(base, sizeof(base), udev_get_sys_path(udev), "/class/block", NULL);
-               if (stat(base, &statbuf) != 0) {
-                       if (match_subsystem(udev_enumerate, "block")) {
-                               dbg(udev, "searching '/block/*' dir\n");
-                               /* scan disks */
-                               scan_dir_and_add_devices(udev_enumerate, "block", NULL, NULL);
-                               /* scan partitions */
-                               dbg(udev, "searching '/block/*/*' dir\n");
-                               scan_dir(udev_enumerate, "block", NULL, "block");
-                       }
-               }
        }
        return 0;
 }