elf/dl-tunable-types.h

   1 /* Internal representation of tunables.
   2
   3    Copyright (C) 2016-2024 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <https://www.gnu.org/licenses/>.  */
  19
  20 #ifndef _TUNABLE_TYPES_H_
  21 #define _TUNABLE_TYPES_H_
  22
  23 /* Note: This header is included in the generated dl-tunables-list.h and
  24    only used internally in the tunables implementation in dl-tunables.c.  */
  25
  26 #include <stdbool.h>
  27 #include <stddef.h>
  28 #include <stdint.h>
  29
  30 typedef enum
  31 {
  32   TUNABLE_TYPE_INT_32,
  33   TUNABLE_TYPE_UINT_64,
  34   TUNABLE_TYPE_SIZE_T,
  35   TUNABLE_TYPE_STRING
  36 } tunable_type_code_t;
  37
  38 typedef struct
  39 {
  40   tunable_type_code_t type_code;
  41   tunable_num_t min;
  42   tunable_num_t max;
  43 } tunable_type_t;
  44
  45 /* Security level for tunables.  This decides what to do with individual
  46    tunables for AT_SECURE binaries.  */
  47 typedef enum
  48 {
  49   /* Erase the tunable for AT_SECURE binaries so that child processes don't
  50      read it.  */
  51   TUNABLE_SECLEVEL_SXID_ERASE = 0,
  52   /* Ignore the tunable for AT_SECURE binaries, but don't erase it, so that
  53      child processes can read it.  */
  54   TUNABLE_SECLEVEL_SXID_IGNORE = 1,
  55   /* Read the tunable.  */
  56   TUNABLE_SECLEVEL_NONE = 2,
  57 } tunable_seclevel_t;
  58
  59 /* A tunable.  */
  60 struct _tunable
  61 {
  62   const char name[TUNABLE_NAME_MAX];    /* Internal name of the tunable.  */
  63   tunable_type_t type;                  /* Data type of the tunable.  */
  64   const tunable_val_t def;              /* The value.  */
  65   tunable_val_t val;                    /* The value.  */
  66   bool initialized;                     /* Flag to indicate that the tunable is
  67                                            initialized.  */
  68   /* Compatibility elements.  */
  69   const char env_alias[TUNABLE_ALIAS_MAX]; /* The compatibility environment
  70                                            variable name.  */
  71 };
  72
  73 typedef struct _tunable tunable_t;
  74
  75 static __always_inline bool
  76 unsigned_tunable_type (tunable_type_code_t t)
  77 {
  78   switch (t)
  79     {
  80     case TUNABLE_TYPE_INT_32:
  81       return false;
  82     case TUNABLE_TYPE_UINT_64:
  83     case TUNABLE_TYPE_SIZE_T:
  84       return true;
  85     case TUNABLE_TYPE_STRING:
  86     default:
  87       break;
  88     }
  89   __builtin_unreachable ();
  90 }
  91
  92 #endif