1 /* Determine whether the current process is running under QEMU.
2 Copyright (C) 2021 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 #include <stdbool.h>
20 #ifdef __linux__
21 # include <fcntl.h>
22 # include <string.h>
23 # include <unistd.h>
24 #endif
25
26 /* This function determines whether the current process is running under QEMU
27 (user-mode).
28
29 It does so by looking at parts of the environment that QEMU does not emulate
30 100% perfectly well.
31
32 For comparison, the techniques given in the paper
33 Thomas Raffetseder, Christopher Kruegel, Engin Kirda
34 "Detecting System Emulators"
35 2007
36 https://publik.tuwien.ac.at/files/pub-inf_5317.pdf
37 apply to both the QEMU system mode and QEMU user mode. */
38
39 static bool
is_running_under_qemu_user(void)40 is_running_under_qemu_user (void)
41 {
42 #ifdef __linux__
43 char buf[4096 + 1];
44 int fd;
45
46 # if defined __m68k__
47 fd = open ("/proc/hardware", O_RDONLY);
48 if (fd >= 0)
49 {
50 int n = read (fd, buf, sizeof (buf) - 1);
51 close (fd);
52 if (n > 0)
53 {
54 buf[n] = '\0';
55 if (strstr (buf, "qemu") != NULL)
56 return true;
57 }
58 }
59 # endif
60
61 fd = open ("/proc/cpuinfo", O_RDONLY);
62 if (fd >= 0)
63 {
64 int n = read (fd, buf, sizeof (buf) - 1);
65 close (fd);
66 if (n > 0)
67 {
68 buf[n] = '\0';
69 # if defined __hppa__
70 if (strstr (buf, "QEMU") != NULL)
71 return true;
72 # endif
73 # if !(defined __i386__ || defined __x86_64__)
74 if (strstr (buf, "AuthenticAMD") != NULL
75 || strstr (buf, "GenuineIntel") != NULL)
76 return true;
77 # endif
78 # if !(defined __arm__ || defined __aarch64__)
79 if (strstr (buf, "ARM") != NULL
80 || strcasestr (buf, "aarch64") != NULL)
81 return true;
82 # endif
83 # if !defined __sparc__
84 if (strcasestr (buf, "SPARC") != NULL)
85 return true;
86 # endif
87 # if !defined __powerpc__
88 if (strstr (buf, "POWER") != NULL)
89 return true;
90 # endif
91 }
92 }
93
94 /* If you need more heuristics, look at system calls that are not perfectly
95 well emulated in qemu/linux-user/syscall.c. */
96 #endif
97
98 return false;
99 }
100