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 "2002" "Linux" "Linux Module Support"
   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 ",
  16 .BI "void *" buf ", 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 Always returns success.
  41 Used to probe for availability of the system call.
  42 .TP
  43 .B QM_MODULES
  44 Returns the names of all loaded modules.
  45 The returned buffer consists of a sequence of null-terminated strings;
  46 .I ret
  47 is set to the number of
  48 modules.
  49 .TP
  50 .B QM_DEPS
  51 Returns the names of all modules used by the indicated module.
  52 The returned buffer consists of a sequence of null-terminated strings;
  53 .I ret
  54 is set to the number of modules.
  55 .TP
  56 .B QM_REFS
  57 Returns the names of all modules using the indicated module.  This is
  58 the inverse of
  59 .BR QM_DEPS .
  60 The returned buffer consists of a sequence of null-terminated strings;
  61 .I ret
  62 is set to the number of modules.
  63 .TP
  64 .B QM_SYMBOLS
  65 Returns the symbols and values exported by the kernel or the indicated
  66 module.
  67 The returned buffer is an array of structures of the following form
  68 .RS
  69 .PP
  70 .nf
  71 struct module_symbol {
  72     unsigned long value;
  73     unsigned long name;
  74 };
  75 .fi
  76 .PP
  77 followed by null-terminated strings.
  78 The value of
  79 .I name
  80 is the character offset of the string relative to the start of
  81 .IR buf ;
  82 .I ret
  83 is set to the number of symbols.
  84 .RE
  85 .TP
  86 .B QM_INFO
  87 Returns miscellaneous information about the indicated module.  The output
  88 buffer format is:
  89 .RS
  90 .PP
  91 .nf
  92 struct module_info {
  93     unsigned long address;
  94     unsigned long size;
  95     unsigned long flags;
  96 };
  97 .fi
  98 .PP
  99 where
 100 .I address
 101 is the kernel address at which the module resides,
 102 .I size
 103 is the size of the module in bytes, and
 104 .I flags
 105 is a mask of
 106 .BR MOD_RUNNING ,
 107 .BR MOD_AUTOCLEAN ,
 108 etc. that indicates the current status of the module
 109 (see the kernel source file
 110 .IR include/linux/module.h ).
 111 .I ret
 112 is set to the size of the
 113 .I module_info
 114 structure.
 115 .RE
 116 .SH "RETURN VALUE"
 117 On success, zero is returned.  On error, \-1 is returned and
 118 .I errno
 119 is set appropriately.
 120 .SH ERRORS
 121 .TP
 122 .B EFAULT
 123 At least one of
 124 .IR name ,
 125 .IR buf ,
 126 or
 127 .I ret
 128 was outside the program's accessible address space.
 129 .TP
 130 .B EINVAL
 131 Invalid
 132 .IR which ;
 133 or
 134 .I name
 135 is NULL (indicating "the kernel"),
 136 but this is not permitted with the specified value of
 137 .IR which .
 138 .\" Not permitted with QM_DEPS, QM_REFS, or QM_INFO.
 139 .TP
 140 .B ENOENT
 141 No module by that
 142 .I name
 143 exists.
 144 .TP
 145 .B ENOSPC
 146 The buffer size provided was too small.
 147 .I ret
 148 is set to the minimum size needed.
 149 .SH "CONFORMING TO"
 150 .BR query_module ()
 151 is Linux specific.
 152 .SH NOTES
 153 This system call is only present on Linux up until kernel 2.4;
 154 it was removed in Linux 2.6.
 155 .\" Removed in Linux-2.5.48
 156 Some of the information that was available via
 157 .BR query_module ()
 158 can be obtained from
 159 .IR /proc/modules ,
 160 .IR /proc/kallsyms ,
 161 and
 162 .IR /sys/modules .
 163 .SH "SEE ALSO"
 164 .BR create_module (2),
 165 .BR delete_module (2),
 166 .BR get_kernel_syms (2),
 167 .BR init_module (2)