tests/qemu.h

   1 /* Determine whether the current process is running under QEMU.
   2    Copyright (C) 2021-2024 Free Software Foundation, Inc.
   3
   4    This file is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU Lesser General Public License as
   6    published by the Free Software Foundation; either version 2.1 of the
   7    License, or (at your option) any later version.
   8
   9    This file is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Bruno Haible <bruno@clisp.org>, 2021.  */
  18
  19 #ifdef __linux__
  20 # include <fcntl.h>
  21 # include <string.h>
  22 # include <unistd.h>
  23 #endif
  24
  25 /* This function determines whether the current process is running under QEMU
  26    (user-mode).
  27
  28    It does so by looking at parts of the environment that QEMU does not emulate
  29    100% perfectly well.
  30
  31    For comparison, the techniques given in the paper
  32      Thomas Raffetseder, Christopher Kruegel, Engin Kirda
  33      "Detecting System Emulators"
  34      2007
  35      https://publik.tuwien.ac.at/files/pub-inf_5317.pdf
  36    apply to both the QEMU system mode and QEMU user mode.  */
  37
  38 static bool
  39 is_running_under_qemu_user (void)
  40 {
  41 #ifdef __linux__
  42   char buf[4096 + 1];
  43   int fd;
  44
  45 # if defined __m68k__
  46   fd = open ("/proc/hardware", O_RDONLY);
  47   if (fd >= 0)
  48     {
  49       int n = read (fd, buf, sizeof (buf) - 1);
  50       close (fd);
  51       if (n > 0)
  52         {
  53           buf[n] = '\0';
  54           if (strstr (buf, "qemu") != NULL)
  55             return true;
  56         }
  57     }
  58 # endif
  59
  60   fd = open ("/proc/cpuinfo", O_RDONLY);
  61   if (fd >= 0)
  62     {
  63       int n = read (fd, buf, sizeof (buf) - 1);
  64       close (fd);
  65       if (n > 0)
  66         {
  67           buf[n] = '\0';
  68 # if defined __hppa__
  69           if (strstr (buf, "QEMU") != NULL)
  70             return true;
  71 # endif
  72 # if !(defined __i386__ || defined __x86_64__)
  73           if (strstr (buf, "AuthenticAMD") != NULL
  74               || strstr (buf, "GenuineIntel") != NULL)
  75             return true;
  76 # endif
  77 # if !(defined __arm__ || defined __aarch64__)
  78           if (strstr (buf, "ARM") != NULL
  79               || strcasestr (buf, "aarch64") != NULL)
  80             return true;
  81 # endif
  82 # if !defined __sparc__
  83           if (strcasestr (buf, "SPARC") != NULL)
  84             return true;
  85 # endif
  86 # if !defined __powerpc__
  87           if (strstr (buf, "POWER") != NULL)
  88             return true;
  89 # endif
  90         }
  91     }
  92
  93   /* If you need more heuristics, look at system calls that are not perfectly
  94      well emulated in qemu/linux-user/syscall.c.  */
  95 #endif
  96
  97   return false;
  98 }