sysdeps/unix/sysv/linux/riscv/readelflib.c

   1 /* Support for reading ELF files.
   2    Copyright (C) 1999-2021 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
  20 int process_elf32_file (const char *file_name, const char *lib,
  21                         int *flag, unsigned int *osversion,
  22                         unsigned int *isa_level, char **soname,
  23                         void *file_contents, size_t file_length);
  24 int process_elf64_file (const char *file_name, const char *lib,
  25                         int *flag, unsigned int *osversion,
  26                         unsigned int *isa_level, char **soname,
  27                         void *file_contents, size_t file_length);
  28
  29 /* The ELF flags supported by our current glibc port:
  30    - EF_RISCV_FLOAT_ABI: We support the soft and double ABIs.
  31    - EF_RISCV_RVC: While the Linux ABI mandates the presence of the C
  32      extension, we can still support libraries compiled without that extension
  33      so we just ignore this flag.
  34    - EF_RISCV_RVE: glibc (and Linux) don't support RV32E based systems.
  35    - EF_RISCV_TSO: The TSO extension isn't supported, as doing so would require
  36      some mechanism to ensure that the TSO extension is enabled which doesn't
  37      currently exist.  */
  38 #define SUPPORTED_ELF_FLAGS (EF_RISCV_FLOAT_ABI | EF_RISCV_RVC)
  39
  40 /* Returns 0 if everything is ok, != 0 in case of error.  */
  41 int
  42 process_elf_file (const char *file_name, const char *lib, int *flag,
  43                   unsigned int *osversion, unsigned int *isa_level,
  44                   char **soname, void *file_contents, size_t file_length)
  45 {
  46   ElfW(Ehdr) *elf_header = (ElfW(Ehdr) *) file_contents;
  47   Elf32_Ehdr *elf32_header = (Elf32_Ehdr *) elf_header;
  48   Elf64_Ehdr *elf64_header = (Elf64_Ehdr *) elf_header;
  49   int ret;
  50   long flags;
  51
  52   /* RISC-V libraries are always libc.so.6+.  */
  53   *flag = FLAG_ELF_LIBC6;
  54
  55   if (elf_header->e_ident [EI_CLASS] == ELFCLASS32)
  56     {
  57       ret = process_elf32_file (file_name, lib, flag, osversion, isa_level,
  58                                 soname, file_contents, file_length);
  59       flags = elf32_header->e_flags;
  60     }
  61   else
  62     {
  63       ret = process_elf64_file (file_name, lib, flag, osversion, isa_level,
  64                                 soname, file_contents, file_length);
  65       flags = elf64_header->e_flags;
  66     }
  67
  68   /* RISC-V linkers encode the floating point ABI as part of the ELF headers.  */
  69   switch (flags & EF_RISCV_FLOAT_ABI)
  70     {
  71       case EF_RISCV_FLOAT_ABI_SOFT:
  72         *flag |= FLAG_RISCV_FLOAT_ABI_SOFT;
  73         break;
  74       case EF_RISCV_FLOAT_ABI_DOUBLE:
  75         *flag |= FLAG_RISCV_FLOAT_ABI_DOUBLE;
  76         break;
  77       default:
  78         return 1;
  79     }
  80
  81   /* If there are any other ELF flags set then glibc doesn't support this
  82      library.  */
  83   if (flags & ~SUPPORTED_ELF_FLAGS)
  84     return 1;
  85
  86   return ret;
  87 }
  88
  89 #undef __ELF_NATIVE_CLASS
  90 #undef process_elf_file
  91 #define process_elf_file process_elf32_file
  92 #define __ELF_NATIVE_CLASS 32
  93 #include "elf/readelflib.c"
  94
  95 #undef __ELF_NATIVE_CLASS
  96 #undef process_elf_file
  97 #define process_elf_file process_elf64_file
  98 #define __ELF_NATIVE_CLASS 64
  99 #include "elf/readelflib.c"