modload(2)

modload -- load a loadable kernel module on demand

Synopsis

   #include <sys/mod.h>
   
   int modload(const char *pathname);

Description

modload allows processes with privilege P_LOADMOD to demand-load a loadable module into a running system.

pathname gives the pathname of the module to be loaded, specified either as a module name or as an absolute pathname. If pathname specifies a module name, modload searches for the module's object file on disk in the list of directories set by modpath(2) (including the default directory /etc/conf/mod.d). If pathname specifies an absolute pathname, only pathname is used to locate the module's object file.

Tasks performed during the load operation include:

open the module's object file on disk
allocate kernel memory to hold the module
read the module's object file into memory
load any modules upon which the module depends that are not already loaded
relocate the module's symbols
resolve any external references to kernel symbols made by the module
execute the module's wrapper routine to perform any setup the module requires to initialize itself
logically link the module to the running kernel by creating the module's switch table entries
set a flag that prevents the module from being unloaded by the kernel auto-unload mechanism

Return values

On success, modload returns the integer module id of the loaded module. On failure, modload returns -1 and sets errno to identify the error.

Errors

In the following conditions, modload fails and sets errno to:

EACCES: Search permission was denied by a pathname component.
ENOENT: The file pathname does not exist.
EINVAL: The file pathname is not preconfigured for dynamic loading or has invalid dependencies on other modules (such as a circular dependency).
EPERM: The caller does not possess P_LOADMOD privileges.
ERELOC: Error occurred processing the module's object file, or the module references symbols not defined in the running kernel, or the module references symbols in another loadable module, but it did not define its dependence on this module in its Master file.
EBADVER: The version number specified in the module's wrapper routine does not match the version number for the running kernel.
ENAMETOOLONG: pathname is more than MAXPATHLEN characters long.
ENOSYS: Unable to perform the requested operation because the loadable modules functions are not configured into the system.

References

idbuild(1M), idmodload(1M), idtune(1M), modadmin(1M), modpath(2), modstat(2), moduload(2)