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query_module() - Unix, Linux System Call
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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);
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DESCRIPTION
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:
| Tag | Description |
|---|
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0 |
Always returns success.
Used to probe for availability of the system call.
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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.
|
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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.
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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;
};
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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.
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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;
};
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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 kernel source file
include/linux/module.h). ret is set to the size of the
module_info structure.
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RETURN VALUE
On success, zero is returned. On error, -1 is returned and
errno is set appropriately.
ERRORS
| Tag | Description |
|---|
|
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.
|
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ENOSPC |
The buffer size provided was too small.
ret is set to the minimum size needed.
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CONFORMING TO
query_module() is Linux specific.
NOTES
This system call is only present on Linux up until kernel 2.4;
it was removed in Linux 2.6.
Some of the information that was available via
query_module() can be obtained from
/proc/modules, /proc/kallsyms, and
/sys/modules. SEE ALSO
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