The -D option provides limited means for specifying the device
cache file path. Its ? function will report the read-only and
write device cache file paths that lsof will use.
When the -D b, r, and u functions are available, you can use them
to request that the cache file be built in a specific location
(b[path]); read but not rebuilt (r[path]); or read and rebuilt
(u[path]). The b, r, and u functions are restricted under some
conditions. They are restricted when the lsof process is
setuid-root. The path specified with the r function is always
read-only, even when it is available.
The b, r, and u functions are also restricted when the lsof
process runs setgid and lsof doesn't surrender the setgid
permission. (See the LSOF PERMISSIONS THAT AFFECT DEVICE CACHE
FILE ACCESS section for a list of implementations that normally
don't surrender their setgid permission.)
A further -D function, i (for ignore), is always available.
When available, the b function tells lsof to read device
information from the kernel with the stat(2) function and build a
device cache file at the indicated path.
When available, the r function tells lsof to read the device
cache file, but not update it. When a path argument accompanies
-Dr, it names the device cache file path. The r function is
always available when it is specified without a path name
argument. If lsof is not running setuid-root and surrenders its
setgid permission, a path name argument may accompany the r
function.
When available, the u function tells lsof to attempt to read and
use the device cache file. If it can't read the file, or if it
finds the contents of the file incorrect or outdated, it will
read information from the kernel, and attempt to write an updated
version of the device cache file, but only to a path it considers
legitimate for the lsof process effective and real UIDs.
