depmod

8

depmod

program to generate `modules.dep` and map files.

          depmod
          -b basedir
          -e
          -F System.map
          -n
          -v
          version
          -A

          depmod
          -e
          -FSystem.map
          -n
          -v
          version
          filename

## DESCRIPTION

Linux kernel modules can provide services (called "symbols") for other modules to use (using EXPORT_SYMBOL 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 `/lib/modules/``version` and determining what symbols it exports, and what symbols it needs. By default this list is written to `modules.dep` 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).

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 map files in this directory, for use by the hotplug infrastructure.

## OPTIONS

`-a` `--all`

- Probe all modules. This option is enabled by default if no file names are given in the command-line.

`-A` `--quick`

- 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) directory `/lib/modules/``version`, 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.

`-C` `--config `file or directory``

- This option overrides the default configuration file (/etc/depmod.conf or /etc/depmod.d/ if that isn’t found).

`-e` `--errsyms`

- 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).

`-F` `--filesyms `System.map``

- Supplied with the `System.map` produced when the kernel was built, this allows the `-e` option to report unresolved symbols.

`-h` `--help`

- Print the help message, and exit.

`-n` `--dry-run`

- This sends the resulting modules.dep, then the various map files, to standard output, rather than writing them into the module directory.

`-v` `--verbose`

- 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.

`-V` `--version`

- Show version of program, and exit. See below for caveats when run on older kernels.

## BACKWARDS COMPATIBILITY

This version of `depmod` is for kernels `2.5.48` and above. If it detects a kernel with support for old-style modules, or the version specified is before `2.5.48`, it will attempt to run `depmod.old` in its place, so it is completely transparent to the user.

## COPYRIGHT

This manual page Copyright 2002, Rusty Russell, IBM Corporation.

## SEE ALSO

modprobe

8 ,

modules.dep

5 ,

depmod.old

8