[vlc-devel] [PATCH] Udev SD: Try to find out the mount point for blu-ray discs.

[Konstantin Pavlov]

On Wed, Feb 15, 2012 at 06:09:41PM +0100, Rémi Denis-Courmont wrote:
> On Wed, 15 Feb 2012 20:18:40 +0400, Konstantin Pavlov
> <thresh at videolan.org>
> wrote:
> > On Wed, Feb 15, 2012 at 04:39:02PM +0100, Rémi Denis-Courmont wrote:
> >> >> > +        while ((m = getmntent_r (mtab, &mbuf, buf, sizeof(buf)))
> !=
> >> >> NULL)
> >> >> > +        {
> >> >> > +            if( !strcmp (m->mnt_fsname, val)) val = m->mnt_dir;
> >> >> > +        }
> >> >> > +        endmntent (mtab);
> >> >> > +    }
> >> >> > +
> >> >> >      return make_URI (val, scheme);
> >> >> 
> >> >> This looks like use-after-release to me.
> >> > 
> >> > Uhm, why?
> >> 
> >> val = m->mnt_dir... I don't suppose the storage for that is still
> valid.
> > 
> > The attached patch doesnt re-use val.
> 
> We already went through this. It will fail if the disc is inserted _after_
> the SD plugin starts. By the time udev fires the disc event, the file
> system is obviously not mounted.

You're right.  I moved the check to bluray access, see attached patch.

-- 
Konstantin Pavlov
VideoLAN team
-------------- next part --------------
>From e374130fc2a3caf273d0e31453d59817237e3769 Mon Sep 17 00:00:00 2001
From: Konstantin Pavlov <thresh at videolan.org>
Date: Wed, 15 Feb 2012 16:30:38 +0400
Subject: [PATCH] Bluray: try to find mount point if block device file is
 passed.

---
 modules/access/bluray.c |   24 ++++++++++++++++++++++++
 1 files changed, 24 insertions(+), 0 deletions(-)

diff --git a/modules/access/bluray.c b/modules/access/bluray.c
index 7bfc3f0..9b5660c 100644
--- a/modules/access/bluray.c
+++ b/modules/access/bluray.c
@@ -26,6 +26,10 @@
 
 #include <assert.h>
 #include <limits.h>                         /* PATH_MAX */
+#ifdef HAVE_SYS_STAT_H
+#include <mntent.h>
+#include <sys/stat.h>
+#endif
 
 #include <vlc_common.h>
 #include <vlc_plugin.h>
@@ -122,6 +126,26 @@ static int blurayOpen( vlc_object_t *object )
         bd_path[PATH_MAX - 1] = '\0';
     }
 
+#ifdef HAVE_SYS_STAT_H
+    /* If we're passed a block device, try to convert it to the mount point. */
+    struct stat st;
+    if ( !stat (bd_path, &st)) {
+        if (S_ISBLK (st.st_mode)) {
+            FILE* mtab = setmntent ("/proc/self/mounts", "r");
+            struct mntent* m;
+            struct mntent mbuf;
+            char buf [8192];
+            while ((m = getmntent_r (mtab, &mbuf, buf, sizeof(buf))) != NULL) {
+                if (!strcmp (m->mnt_fsname, bd_path)) {
+                    strncpy (bd_path, m->mnt_dir, sizeof(bd_path));
+                    bd_path[sizeof(bd_path) - 1] = '\0';
+                    break;
+                }
+            }
+            endmntent (mtab);
+        }
+    }
+#endif /* HAVE_SYS_STAT_H */
     p_sys->bluray = bd_open(bd_path, NULL);
     if (!p_sys->bluray) {
         free(p_sys);
-- 
1.7.8.4