man2/get_kernel_syms.2

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  10 .TH GET_KERNEL_SYMS 2 2016-10-08 "Linux" "Linux Programmer's Manual"
  11 .SH NAME
  12 get_kernel_syms \- retrieve exported kernel and module symbols
  13 .SH SYNOPSIS
  14 .nf
  15 .B #include <linux/module.h>
  16 .PP
  17 .BI "int get_kernel_syms(struct kernel_sym *" table );
  18 .fi
  19 .PP
  20 .IR Note :
  21 No declaration of this system call is provided in glibc headers; see NOTES.
  22 .SH DESCRIPTION
  23 .BR Note :
  24 This system call is present only in kernels before Linux 2.6.
  25 .PP
  26 If
  27 .I table
  28 is NULL,
  29 .BR get_kernel_syms ()
  30 returns the number of symbols available for query.
  31 Otherwise, it fills in a table of structures:
  32 .PP
  33 .in +4n
  34 .nf
  35 struct kernel_sym {
  36     unsigned long value;
  37     char          name[60];
  38 };
  39 .fi
  40 .in
  41 .PP
  42 The symbols are interspersed with magic symbols of the form
  43 .BI # module-name
  44 with the kernel having an empty name.
  45 The value associated with a symbol of this form is the address at
  46 which the module is loaded.
  47 .PP
  48 The symbols exported from each module follow their magic module tag
  49 and the modules are returned in the reverse of the
  50 order in which they were loaded.
  51 .SH RETURN VALUE
  52 On success, returns the number of symbols copied to
  53 .IR table .
  54 On error, \-1 is returned and
  55 .I errno
  56 is set appropriately.
  57 .SH ERRORS
  58 There is only one possible error return:
  59 .TP
  60 .B ENOSYS
  61 .BR get_kernel_syms ()
  62 is not supported in this version of the kernel.
  63 .SH VERSIONS
  64 This system call is present on Linux only up until kernel 2.4;
  65 it was removed in Linux 2.6.
  66 .\" Removed in Linux 2.5.48
  67 .SH CONFORMING TO
  68 .BR get_kernel_syms ()
  69 is Linux-specific.
  70 .SH NOTES
  71 This obsolete system call is not supported by glibc.
  72 No declaration is provided in glibc headers, but, through a quirk of history,
  73 glibc versions before 2.23 did export an ABI for this system call.
  74 Therefore, in order to employ this system call,
  75 it was sufficient to manually declare the interface in your code;
  76 alternatively, you could invoke the system call using
  77 .BR syscall (2).
  78 .SH BUGS
  79 There is no way to indicate the size of the buffer allocated for
  80 .IR table .
  81 If symbols have been added to the kernel since the
  82 program queried for the symbol table size, memory will be corrupted.
  83 .PP
  84 The length of exported symbol names is limited to 59 characters.
  85 .PP
  86 Because of these limitations, this system call is deprecated in
  87 favor of
  88 .BR query_module (2)
  89 (which is itself nowadays deprecated
  90 in favor of other interfaces described on its manual page).
  91 .SH SEE ALSO
  92 .BR create_module (2),
  93 .BR delete_module (2),
  94 .BR init_module (2),
  95 .BR query_module (2)