Linux kernel modules can provide services (called "symbols") for
other modules to use (using one of the EXPORT_SYMBOL variants in the
code). If a second module uses this symbol, that second module clearly
depends on the first module. These dependencies can get quite complex.
depmod creates a list of module dependencies
by reading each module under
and determining what symbols it exports and what symbols it
needs. By default, this list is written to
modules.dep, and a binary hashed version named
modules.dep.bin, in the same directory. If
filenames are given on the command line, only those modules are
examined (which is rarely useful unless all modules are listed).
depmod also creates a list of symbols provided
by modules in the file named modules.symbols
and its binary hashed version, modules.symbols.bin.
If a version is provided, then that
kernel version's module directory is used rather than the
current kernel version (as returned by uname -r).
depmod will also generate various legacy map
files in the output directory for use by the older hotplug
infrastructure. These map files are largely deprecated.
Probe all modules. This option is enabled by default if no
file names are given in the command-line.
This option scans to see if any modules are newer than the
modules.dep file before any work is done:
if not, it silently exits rather than regenerating the files.
-b basedir --basedir basedir
If your modules are not currently in the (normal)
but in a staging area, you can specify a
basedir which is prepended to
the directory name. This
basedir is stripped from the
resulting modules.dep file, so it
is ready to be moved into the normal location. Use this option
if you are a distribution vendor who needs to pre-generate the
meta-data files rather than running depmod again later.
-C --config file or directory
This option overrides the default configuration file at
/etc/depmod.conf (or the
/etc/depmod.d/ directory if that is not found).
When combined with the -F option, this
reports any symbols which a module needs which are not
supplied by other modules or the kernel. Normally, any
symbols not provided by modules are assumed to be
provided by the kernel (which should be true in a
perfect world), but this assumption can break espencially
when additionally updated third party drivers are not
correctly installed or were built incorrectly.
-F --filesyms System.map
Supplied with the System.map produced
when the kernel was built, this allows the
-e option to report unresolved symbols.
Print the help message and exit.
This sends the resulting modules.dep and the various
map files to standard output rather than writing them into
the module directory.
In verbose mode, depmod will print (to stdout)
all the symbols each module depends on and the module's file name
which provides that symbol.
Show version of program and exit. See below for caveats when
run on older kernels.
This manual page originally Copyright 2002, Rusty Russell,
IBM Corporation. Maintained by Jon Masters and others.