1 /* Parse the Linux auxiliary vector.
2    Copyright (C) 1995-2022 Free Software Foundation, Inc.
3    This file is part of the GNU C Library.
4 
5    The GNU C Library is free software; you can redistribute it and/or
6    modify it under the terms of the GNU Lesser General Public
7    License as published by the Free Software Foundation; either
8    version 2.1 of the License, or (at your option) any later version.
9 
10    The GNU C Library is distributed in the hope that it will be useful,
11    but WITHOUT ANY WARRANTY; without even the implied warranty of
12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13    Lesser General Public License for more details.
14 
15    You should have received a copy of the GNU Lesser General Public
16    License along with the GNU C Library; if not, see
17    <https://www.gnu.org/licenses/>.  */
18 
19 #include <elf.h>
20 #include <entry.h>
21 #include <fpu_control.h>
22 #include <ldsodefs.h>
23 #include <link.h>
24 
25 typedef ElfW(Addr) dl_parse_auxv_t[AT_MINSIGSTKSZ + 1];
26 
27 /* Copy the auxiliary vector into AUXV_VALUES and set up GLRO
28    variables.  */
29 static inline
_dl_parse_auxv(ElfW (auxv_t)* av,dl_parse_auxv_t auxv_values)30 void _dl_parse_auxv (ElfW(auxv_t) *av, dl_parse_auxv_t auxv_values)
31 {
32   auxv_values[AT_ENTRY] = (ElfW(Addr)) ENTRY_POINT;
33   auxv_values[AT_PAGESZ] = EXEC_PAGESIZE;
34   auxv_values[AT_FPUCW] = _FPU_DEFAULT;
35 
36   /* NB: Default to a constant CONSTANT_MINSIGSTKSZ.  */
37   _Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ),
38                   "CONSTANT_MINSIGSTKSZ is constant");
39   auxv_values[AT_MINSIGSTKSZ] = CONSTANT_MINSIGSTKSZ;
40 
41   for (; av->a_type != AT_NULL; av++)
42     if (av->a_type <= AT_MINSIGSTKSZ)
43       auxv_values[av->a_type] = av->a_un.a_val;
44 
45   GLRO(dl_pagesize) = auxv_values[AT_PAGESZ];
46   __libc_enable_secure = auxv_values[AT_SECURE];
47   GLRO(dl_platform) = (void *) auxv_values[AT_PLATFORM];
48   GLRO(dl_hwcap) = auxv_values[AT_HWCAP];
49   GLRO(dl_hwcap2) = auxv_values[AT_HWCAP2];
50   GLRO(dl_clktck) = auxv_values[AT_CLKTCK];
51   GLRO(dl_fpu_control) = auxv_values[AT_FPUCW];
52   _dl_random = (void *) auxv_values[AT_RANDOM];
53   GLRO(dl_minsigstacksize) = auxv_values[AT_MINSIGSTKSZ];
54   GLRO(dl_sysinfo_dso) = (void *) auxv_values[AT_SYSINFO_EHDR];
55 #ifdef NEED_DL_SYSINFO
56   if (GLRO(dl_sysinfo_dso) != NULL)
57     GLRO(dl_sysinfo) = auxv_values[AT_SYSINFO];
58 #endif
59 
60   DL_PLATFORM_AUXV
61 }
62