QUERY_MODULE
Section: Linux Programmer's Manual (2)
Updated: 2017-09-15
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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:
No declaration of this system call is provided in glibc headers; 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,
and so on, 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.
The
query_module()
system call is not supported by glibc.
No declaration is provided in glibc headers, but,
through a quirk of history, glibc does export an ABI for this system call.
Therefore, in order to employ this system call,
it is sufficient to manually declare the interface in your code;
alternatively, you can invoke the system call using
syscall(2).
SEE ALSO
create_module(2),
delete_module(2),
get_kernel_syms(2),
init_module(2),
lsmod(8),
modinfo(8)
COLOPHON
This page is part of release 4.13 of the Linux
man-pages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
https://www.kernel.org/doc/man-pages/.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- VERSIONS
-
- CONFORMING TO
-
- NOTES
-
- SEE ALSO
-
- COLOPHON
-
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