query_module

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);

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

DESCRIPTION
       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
       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
              (e.g., the kernel is version 2.6 or later).

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

CONFORMING TO
       query_module() is Linux-specific.

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

COLOPHON
       This page is part of release 5.10 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                              2017-09-15                    QUERY_MODULE(2)