query_module(2)

1query_module(2)               System Calls Manual              query_module(2)
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NAME

6       query_module - query the kernel for various bits pertaining to modules
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SYNOPSIS

9       #include <linux/module.h>
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11       [[deprecated]] int query_module(const char *name, int which,
12                                       void buf[.bufsize], size_t bufsize,
13                                       size_t *ret);
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DESCRIPTION

16       Note: This system call is present only before Linux 2.6.
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18       query_module() requests information from the kernel about loadable mod‐
19       ules.  The returned information is placed in the buffer pointed  to  by
20       buf.   The caller must specify the size of buf in bufsize.  The precise
21       nature and format of the returned information depend on  the  operation
22       specified  by  which.   Some operations require name to identify a cur‐
23       rently loaded module, some allow name to be NULL, indicating the kernel
24       proper.
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26       The following values can be specified for which:
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28       0      Returns success, if the kernel supports query_module().  Used to
29              probe for availability of the system call.
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31       QM_MODULES
32              Returns the names of all loaded modules.   The  returned  buffer
33              consists of a sequence of null-terminated strings; ret is set to
34              the number of modules.
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36       QM_DEPS
37              Returns the names of all modules used by the  indicated  module.
38              The  returned  buffer  consists of a sequence of null-terminated
39              strings; ret is set to the number of modules.
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41       QM_REFS
42              Returns the names of all modules  using  the  indicated  module.
43              This is the inverse of QM_DEPS.  The returned buffer consists of
44              a sequence of null-terminated strings; ret is set to the  number
45              of modules.
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47       QM_SYMBOLS
48              Returns the symbols and values exported by the kernel or the in‐
49              dicated module.  The returned buffer is an array  of  structures
50              of the following form
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52                  struct module_symbol {
53                      unsigned long value;
54                      unsigned long name;
55                  };
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57              followed  by  null-terminated strings.  The value of name is the
58              character offset of the string relative to the start of buf; ret
59              is set to the number of symbols.
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61       QM_INFO
62              Returns  miscellaneous  information  about the indicated module.
63              The output buffer format is:
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65                  struct module_info {
66                      unsigned long address;
67                      unsigned long size;
68                      unsigned long flags;
69                  };
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71              where address is the kernel address at which the module resides,
72              size  is the size of the module in bytes, and flags is a mask of
73              MOD_RUNNING, MOD_AUTOCLEAN, and so on, that indicates  the  cur‐
74              rent  status of the module (see the Linux kernel source file in‐
75              clude/linux/module.h).  ret is set  to  the  size  of  the  mod‐
76              ule_info structure.
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RETURN VALUE

79       On  success,  zero  is returned.  On error, -1 is returned and errno is
80       set to indicate the error.
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ERRORS

83       EFAULT At least one of name, buf, or ret was outside the program's  ac‐
84              cessible address space.
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86       EINVAL Invalid  which;  or  name is NULL (indicating "the kernel"), but
87              this is not permitted with the specified value of which.
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89       ENOENT No module by that name exists.
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91       ENOSPC The buffer size provided was too small.  ret is set to the mini‐
92              mum size needed.
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94       ENOSYS query_module()  is  not  supported in this version of the kernel
95              (e.g., Linux 2.6 or later).
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STANDARDS

98       Linux.
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VERSIONS

101       Removed in Linux 2.6.
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103       Some of the information that was formerly available via  query_module()
104       can be obtained from /proc/modules, /proc/kallsyms, and the files under
105       the directory /sys/module.
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107       The query_module() system call is not supported by glibc.  No  declara‐
108       tion  is  provided  in  glibc headers, but, through a quirk of history,
109       glibc does export an ABI for this system call.  Therefore, in order  to
110       employ  this  system call, it is sufficient to manually declare the in‐
111       terface in your code; alternatively, you can invoke the system call us‐
112       ing syscall(2).
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