man2/query_module.2

   1 .\" Copyright (C) 1996 Free Software Foundation, Inc.
   2 .\" This file is distributed according to the GNU General Public License.
   3 .\" See the file COPYING in the top level source directory for details.
   4 .\"
   5 .\" 2006-02-09, some reformatting by Luc Van Oostenryck; some
   6 .\" reformatting and rewordings by mtk
   7 .\"
   8 .TH QUERY_MODULE 2 2007-06-03 "Linux" "Linux Programmer's Manual"
   9 .SH NAME
  10 query_module \- query the kernel for various bits pertaining to modules
  11 .SH SYNOPSIS
  12 .nf
  13 .B #include <linux/module.h>
  14 .sp
  15 .BI "int query_module(const char *" name ", int " which ", void *" buf ,
  16 .BI "                 size_t " bufsize ", size_t *" ret );
  17 .fi
  18 .SH DESCRIPTION
  19 .BR query_module ()
  20 requests information from the kernel about loadable modules.
  21 The returned information is placed in the buffer pointed to by
  22 .IR buf .
  23 The caller must specify the size of
  24 .I buf
  25 in
  26 .IR bufsize .
  27 The precise nature and format of the returned information
  28 depend on the operation specified by
  29 .IR which .
  30 Some operations require
  31 .I name
  32 to identify a currently loaded module, some allow
  33 .I name
  34 to be NULL, indicating the kernel proper.
  35
  36 The following values can be specified for
  37 .IR which :
  38 .TP
  39 .B 0
  40 Returns success, if the kernel supports
  41 .BR query_module ().
  42 Used to probe for availability of the system call.
  43 .TP
  44 .B QM_MODULES
  45 Returns the names of all loaded modules.
  46 The returned buffer consists of a sequence of null-terminated strings;
  47 .I ret
  48 is set to the number of
  49 modules.
  50 .TP
  51 .B QM_DEPS
  52 Returns the names of all modules used by the indicated module.
  53 The returned buffer consists of a sequence of null-terminated strings;
  54 .I ret
  55 is set to the number of modules.
  56 .TP
  57 .B QM_REFS
  58 Returns the names of all modules using the indicated module.
  59 This is the inverse of
  60 .BR QM_DEPS .
  61 The returned buffer consists of a sequence of null-terminated strings;
  62 .I ret
  63 is set to the number of modules.
  64 .TP
  65 .B QM_SYMBOLS
  66 Returns the symbols and values exported by the kernel or the indicated
  67 module.
  68 The returned buffer is an array of structures of the following form
  69 .RS
  70 .PP
  71 .nf
  72 struct module_symbol {
  73     unsigned long value;
  74     unsigned long name;
  75 };
  76 .fi
  77 .PP
  78 followed by null-terminated strings.
  79 The value of
  80 .I name
  81 is the character offset of the string relative to the start of
  82 .IR buf ;
  83 .I ret
  84 is set to the number of symbols.
  85 .RE
  86 .TP
  87 .B QM_INFO
  88 Returns miscellaneous information about the indicated module.
  89 The output buffer format is:
  90 .RS
  91 .PP
  92 .nf
  93 struct module_info {
  94     unsigned long address;
  95     unsigned long size;
  96     unsigned long flags;
  97 };
  98 .fi
  99 .PP
 100 where
 101 .I address
 102 is the kernel address at which the module resides,
 103 .I size
 104 is the size of the module in bytes, and
 105 .I flags
 106 is a mask of
 107 .BR MOD_RUNNING ,
 108 .BR MOD_AUTOCLEAN ,
 109 etc. that indicates the current status of the module
 110 (see the kernel source file
 111 .IR include/linux/module.h ).
 112 .I ret
 113 is set to the size of the
 114 .I module_info
 115 structure.
 116 .RE
 117 .SH "RETURN VALUE"
 118 On success, zero is returned.
 119 On error, \-1 is returned and
 120 .I errno
 121 is set appropriately.
 122 .SH ERRORS
 123 .TP
 124 .B EFAULT
 125 At least one of
 126 .IR name ,
 127 .IR buf ,
 128 or
 129 .I ret
 130 was outside the program's accessible address space.
 131 .TP
 132 .B EINVAL
 133 Invalid
 134 .IR which ;
 135 or
 136 .I name
 137 is NULL (indicating "the kernel"),
 138 but this is not permitted with the specified value of
 139 .IR which .
 140 .\" Not permitted with QM_DEPS, QM_REFS, or QM_INFO.
 141 .TP
 142 .B ENOENT
 143 No module by that
 144 .I name
 145 exists.
 146 .TP
 147 .B ENOSPC
 148 The buffer size provided was too small.
 149 .I ret
 150 is set to the minimum size needed.
 151 .TP
 152 .B ENOSYS
 153 .BR query_module ()
 154 is not supported in this version of the kernel.
 155 .SH "CONFORMING TO"
 156 .BR query_module ()
 157 is Linux specific.
 158 .SH NOTES
 159 This system call is only present on Linux up until kernel 2.4;
 160 it was removed in Linux 2.6.
 161 .\" Removed in Linux-2.5.48
 162 Some of the information that was available via
 163 .BR query_module ()
 164 can be obtained from
 165 .IR /proc/modules ,
 166 .IR /proc/kallsyms ,
 167 and
 168 .IR /sys/modules .
 169 .SH "SEE ALSO"
 170 .BR create_module (2),
 171 .BR delete_module (2),
 172 .BR get_kernel_syms (2),
 173 .BR init_module (2)