This chapter introduced the following kernel symbols.
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/etc/modules.conf This is the configuration file for modprobe and depmod. It is used to configure demand loading and is described in the manpages for the two programs.
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#include <linux/kmod.h>,int request_module(const char *name); -
void inter_module_register(const char *string, struct module *module, const void *data);,void inter_module_unregister(const char *); inter_module_register makes data available to other modules via the inter-module communication system. When the data is no longer to be shared, inter_module_unregister will end that availability.
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const void *inter_module_get(const char *string);,const void *inter_module_get_request(const char *string, const char *module);,void inter_module_put(const char *string); The first two functions look up a string in the intermodule communication system; inter_module_get_request also attempts to load the given
moduleif the string is not found. Both increment the usage count of the module that exported the string; inter_module_put should be called to decrement it when the data pointer is no longer needed.-
#include <linux/config.h>,CONFIG_MODVERSIONS This macro is defined only if the current kernel has been compiled to support versioned symbols.
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#ifdef MODVERSIONS,#include <linux/modversions.h> This header, which exists only if
CONFIG_MODVERSIONSis valid, contains the versioned names for all the symbols exported by the kernel.-
__GENKSYMS__ This macro is defined by make when preprocessing files to be read by genksyms to build new version codes. It is used to conditionally prevent inclusion of
<linux/modversions.h>when building new checksums.-
int call_usermodehelper(char *path, char *argv[], char *envp[]); This function runs a user-mode program in the keventd process context.