query_module(2) — Linux manual pages

Linux manual pages	Section 2: System Calls

Name

query_module — query the kernel for various bits pertaining to modules

Synopsis

#include <linux/module.h>

`int query_module(`	const char *`name`,
	int `which`,
	void *`buf`,
	size_t `bufsize`,
	size_t *`ret)`;

	Note
	There is no glibc wrapper for this system call; see NOTES.

DESCRIPTION

	Note
	This system call is present only in kernels before Linux 2.6.

query_module() requests information from the kernel about loadable modules. The returned information is placed in the buffer pointed to by buf. The caller must specify the size of buf in bufsize. The precise nature and format of the returned information depend on the operation specified by which. Some operations require name to identify a currently loaded module, some allow name to be NULL, indicating the kernel proper.

The following values can be specified for which:

0

Returns success, if the kernel supports query_module(). Used to probe for availability of the system call.

QM_MODULES

Returns the names of all loaded modules. The returned buffer consists of a sequence of null-terminated strings; ret is set to the number of modules.

QM_DEPS

Returns the names of all modules used by the indicated module. The returned buffer consists of a sequence of null-terminated strings; ret is set to the number of modules.

QM_REFS

Returns the names of all modules using the indicated module. This is the inverse of QM_DEPS. The returned buffer consists of a sequence of null-terminated strings; ret is set to the number of modules.

QM_SYMBOLS

Returns the symbols and values exported by the kernel or the indicated module. The returned buffer is an array of structures of the following form

struct module_symbol {

unsigned long value;

unsigned long name;

};

followed by null-terminated strings. The value of name is the character offset of the string relative to the start of buf; ret is set to the number of symbols.

QM_INFO

Returns miscellaneous information about the indicated module. The output buffer format is:

struct module_info {

unsigned long address;

unsigned long size;

unsigned long flags;

};

where address is the kernel address at which the module resides, size is the size of the module in bytes, and flags is a mask of MOD_RUNNING, MOD_AUTOCLEAN, etc., that indicates the current status of the module (see the Linux kernel source file include/linux/module.h). ret is set to the size of the module_info structure.

RETURN VALUE

On success, zero is returned. On error, −1 is returned and errno is set appropriately.

ERRORS

EFAULT: At least one of name, buf, or ret was outside the program's accessible address space.
EINVAL: Invalid which; or name is NULL (indicating "the kernel"), but this is not permitted with the specified value of which.
ENOENT: No module by that name exists.
ENOSPC: The buffer size provided was too small. ret is set to the minimum size needed.
ENOSYS: query_module() is not supported in this version of the kernel (e.g., the kernel is version 2.6 or later).

VERSIONS

This system call is present on Linux only up until kernel 2.4; it was removed in Linux 2.6.

CONFORMING TO

query_module() is Linux-specific.

NOTES

Some of the information that was formerly available via query_module() can be obtained from /proc/modules, /proc/kallsyms, and the files under the directory /sys/module.

Glibc does not provide a wrapper for this system call; in the unlikely event that you need to use it on an old kernel, use syscall(2).

COLOPHON

This page is part of release 3.52 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man−pages/.

Copyright (C) 1996 Free Software Foundation, Inc.

%%%LICENSE_START(GPL_NOVERSION_ONELINE)
This file is distributed according to the GNU General Public License.
%%%LICENSE_END

2006-02-09, some reformatting by Luc Van Oostenryck; some
reformatting and rewordings by mtk

struct	module_symbol {
	unsigned long	`value`;
	unsigned long	`name`;
};

struct	module_info {
	unsigned long	`address`;
	unsigned long	`size`;
	unsigned long	`flags`;
};