# query_module

## NAME



           query_module - query the kernel for various bits pertaining to
           modules
    


## SYNOPSIS



           **#include <linux/module.h>**
    
           **[[deprecated]] int query_module(** size_t bufsize;
                                           **const char ***_name_**, int** _which_**,**
                                           **void** _buf_**[**_bufsize_**], size_t** _bufsize_**,**
                                           **size_t ***_ret_**);**
    


## DESCRIPTION



           _Note_ : This system call is present only 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 to indicate the error.
    


## 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., Linux 2.6 or later).
    


## STANDARDS



           Linux.
    


## VERSIONS



           Removed in Linux 2.6.
    
           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).
    


* * *