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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 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.

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 infor-
       mation that was available via query_module() can be obtained from /proc/modules, /proc/kallsyms, and  /sys/mod-
       ules.

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

COLOPHON
       This  page  is part of release 3.22 of the Linux man-pages project.  A description of the project, and informa-
       tion about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.



Linux                             2007-06-03                   QUERY_MODULE(2)