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

NAME         top

       query_module - query the kernel for various bits pertaining to modules

SYNOPSIS         top

       #include <linux/module.h>

       int query_module(const char *name, int which, void *buf,
                        size_t bufsize, size_t *ret);

DESCRIPTION         top

       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         top

       On success, zero is returned.  On error, -1 is returned and errno is set
       appropriately.

ERRORS         top

       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         top

       query_module() is Linux-specific.

NOTES         top

       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         top

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

COLOPHON         top

       This page is part of release 3.23 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)