QUERY_MODULE(2)                                     Linux Programmer's Manual                                    QUERY_MODULE(2)



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);

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:

       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  ker-
              nel 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.

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
       create_module(2), delete_module(2), get_kernel_syms(2), init_module(2)

COLOPHON
       This  page  is  part of release 3.25 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/.



Linux                                                      2007-06-03                                            QUERY_MODULE(2)