NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | VERSIONS | CONFORMING TO | NOTES | SEE ALSO | COLOPHON

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

NAME         top

       query_module  -  query the kernel for various bits pertaining to mod‐
       ules

SYNOPSIS         top

       #include <linux/module.h>

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

       Note: No declaration of this system call is provided in glibc
       headers; see NOTES.

DESCRIPTION         top

       Note: This system call is present only in kernels 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         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
              (e.g., the kernel is version 2.6 or later).

VERSIONS         top

       This system call is present on Linux only up until kernel 2.4; it was
       removed in Linux 2.6.

CONFORMING TO         top

       query_module() is Linux-specific.

NOTES         top

       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).

SEE ALSO         top

       create_module(2), delete_module(2), get_kernel_syms(2),
       init_module(2), lsmod(8), modinfo(8)

COLOPHON         top

       This page is part of release 4.08 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at
       https://www.kernel.org/doc/man-pages/.

Linux                            2014-05-10                  QUERY_MODULE(2)