From 7ec51ba998c7a5a4870451fc538b571f79ec633b Mon Sep 17 00:00:00 2001 From: Sami Kerola Date: Thu, 25 Aug 2011 20:54:34 +0200 Subject: docs: add libmount & libblkid debug instructions Signed-off-by: Sami Kerola --- Documentation/howto-debug.txt | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) (limited to 'Documentation') diff --git a/Documentation/howto-debug.txt b/Documentation/howto-debug.txt index bacc61508..28c6e2252 100644 --- a/Documentation/howto-debug.txt +++ b/Documentation/howto-debug.txt @@ -36,3 +36,36 @@ Now external debugging tools can be run on the binary. Happy hacking! Davidlohr Bueso, August 2011 + + +The libmount & libblkid +----------------------- + +Both of the libraries can be debugged by setting an environment variable +consistig a number. The number will be used as a bit mask, so the more 1 the +greater the debugging level. Seach for `DEBUG' from files + + libblkid/src/blkidP.h + libmount/src/mountP.h + +to see what the different bit mean. At the time of writing this the following +enabled full debug. + + export LIBBLKID_DEBUG=0xffff + export LIBMOUNT_DEBUG=0xffff + +The libblkid reads by default /etc/blkid.conf which can be overriden by the +environment variable BLKID_CONF. See manual libblkid/libblkid.3 for details +about the configuration file. + +Block device information is normally kept in a cache file /etc/blkid.tab that +can be overridden by the environment variable BLKID_FILE. + +To libmount uses three paths, which can be override by using environment +variables. Notice that these environment variables are ignored for non-root +users + + env variable if not set defaults to + LIBMOUNT_FSTAB /etc/fstab + LIBMOUNT_MTAB /etc/mtab + LIBMOUNT_UTAB /run/mount/utab or /dev/.mount/utab -- cgit v1.2.3-55-g7522