From: E.Smith <31170571+azlm8t@users.noreply.github.com>
Date: Fri, 13 Oct 2017 00:02:52 +0000 (+0100)
Subject: dvr: Handle symlinks for inotify. (#4702)
X-Git-Tag: v4.2.7~61
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=76a274c98003dbca0bc6600f91f59c5ae6fd1876;p=thirdparty%2Ftvheadend.git

dvr: Handle symlinks for inotify. (#4702)

The filenames stored in the dvr/log are not realpath but can
be based on symlinks.

So, we might record in to /media/Videos/user1/show1 but
user1 could be a symlink to /media/Videos-drive2 (rather than
a bind mount).

Since inotify returns realpaths, if means that when we attempt
to update the dvr/log the filenames do not match.

So we now monitor the realpath for the directories and convert
filenames to realpath when doing the compare.

We do not store realpath in the dvr/log since users do not
want symlinks replaced with real paths.

Issue: #4702.
---

diff --git a/src/dvr/dvr_inotify.c b/src/dvr/dvr_inotify.c
index c568b250a..2c7315bdf 100644
--- a/src/dvr/dvr_inotify.c
+++ b/src/dvr/dvr_inotify.c
@@ -112,14 +112,20 @@ static void dvr_inotify_add_one ( dvr_entry_t *de, htsmsg_t *m )
   dvr_inotify_filename_t *dif;
   dvr_inotify_entry_t *e;
   const char *filename;
-  char *path;
   int fd = atomic_get(&_inot_fd);
 
   filename = htsmsg_get_str(m, "filename");
   if (filename == NULL || fd < 0)
     return;
 
-  path = tvh_strdupa(filename);
+  char path[PATH_MAX];
+  /* Since filename might be inside a symlinked directory
+   * we want to get the true name otherwise when we move
+   * a file we will not match correctly since some files
+   * may point to /mnt/a/z.ts and some to /mnt/b/z.ts
+   */
+  if (!realpath(filename, path))
+    return;
 
   SKEL_ALLOC(dvr_inotify_entry_skel);
   dvr_inotify_entry_skel->path = dirname(path);
@@ -143,6 +149,9 @@ static void dvr_inotify_add_one ( dvr_entry_t *de, htsmsg_t *m )
       tvherror(LS_DVR, "failed to add inotify watch to %s (err=%s)",
                e->path, strerror(errno));
       dvr_inotify_del(de);
+    } else {
+      tvhdebug(LS_DVR, "adding inotify watch to %s (fd=%d)",
+               e->path, e->fd);
     }
 
   }
@@ -240,6 +249,7 @@ _dvr_inotify_moved
     return;
 
   snprintf(path, sizeof(path), "%s/%s", die->path, from);
+  tvhdebug(LS_DVR, "inotify: moved from_fd: %d path: \"%s\" to: \"%s\" to_fd: %d", from_fd, path, to?:"<none>", to_fd);
 
   de = NULL;
   LIST_FOREACH(dif, &die->entries, link) {
@@ -249,8 +259,34 @@ _dvr_inotify_moved
     HTSMSG_FOREACH(f, de->de_files)
       if ((m = htsmsg_field_get_map(f)) != NULL) {
         filename = htsmsg_get_str(m, "filename");
-        if (filename && !strcmp(path, filename))
+        if (!filename)
+          continue;
+
+        /* Simple case of names match */
+        if (!strcmp(path, filename))
           break;
+
+        /* Otherwise get the real path (after symlinks)
+         * and compare that.
+         *
+         * This is made far more complicated since the
+         * file has already disappeared so we can't realpath
+         * on it, so we need to realpath on the directory
+         * it _was_ in, append the filename part and then
+         * compare against the realpath of the path we
+         * were given by inotify.
+         */
+        char *dir = tvh_strdupa(filename);
+        dir = dirname(dir);
+        char realdir[PATH_MAX];
+        if (realpath(dir, realdir)) {
+          char *file = tvh_strdupa(filename);
+          file = basename(file);
+          char complete[PATH_MAX];
+          snprintf(complete, sizeof complete, "%s/%s", realdir, file);
+          if (!strcmp(path, complete))
+            break;
+        }
       }
     if (f)
       break;
@@ -273,8 +309,11 @@ _dvr_inotify_moved
           return;
         }
       }
-      snprintf(path, sizeof(path), "%s/%s", die->path, to);
-      htsmsg_set_str(m, "filename", path);
+      char new_path[PATH_MAX];
+      snprintf(new_path, sizeof(path), "%s/%s", die->path, to);
+      char ubuf[UUID_HEX_SIZE];
+      tvhdebug(LS_DVR, "inotify: moved from name: \"%s\" to: \"%s\" for \"%s\"", path, new_path, idnode_uuid_as_str(&de->de_id, ubuf));
+      htsmsg_set_str(m, "filename", new_path);
       idnode_changed(&de->de_id);
     } else {
       htsmsg_field_destroy(de->de_files, f);