1 files changed, 134 insertions, 0 deletions
diff --git a/tests/virtualbox.h b/tests/virtualbox.h
new file mode 100644
index 00000000..2cc97001
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+++ b/tests/virtualbox.h
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+/* Determine whether the current system is running under VirtualBox/KVM.
+   Copyright (C) 2021-2024 Free Software Foundation, Inc.
+
+   This file is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   This file is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2024.  */
+
+#ifdef __linux__
+# include <fcntl.h>
+# include <string.h>
+# include <unistd.h>
+#endif
+
+/* This function determines whether the current system is Linux and running
+   under the VirtualBox emulator.  */
+_GL_ATTRIBUTE_MAYBE_UNUSED static bool
+is_running_under_virtualbox (void)
+{
+#ifdef __linux__
+  /* On distributions with systemd, this could be done through
+       test `systemd-detect-virt --vm` = oracle
+     More generally, it can be done through
+       test "`cat /sys/class/dmi/id/product_name`" = VirtualBox
+     This is what we do here.  */
+  char buf[4096];
+  int fd = open ("/sys/class/dmi/id/product_name", O_RDONLY);
+  if (fd >= 0)
+    {
+      int n = read (fd, buf, sizeof (buf));
+      close (fd);
+      if (n == 10 + 1 && memcmp (buf, "VirtualBox\n", 10 + 1) == 0)
+        return true;
+    }
+#endif
+
+  return false;
+}
+
+/* This function determines whether the current system is Linux and running
+   under the VirtualBox emulator, with paravirtualization acceleration set to
+   "Default" or "KVM".  */
+static bool
+is_running_under_virtualbox_kvm (void)
+{
+#ifdef __linux__
+  if (is_running_under_virtualbox ())
+    {
+      /* As root, one can determine this paravirtualization mode through
+           dmesg | grep -i kvm
+         which produces output like this:
+           [    0.000000] Hypervisor detected: KVM
+           [    0.000000] kvm-clock: Using msrs 4b564d01 and 4b564d00
+           [    0.000001] kvm-clock: using sched offset of 3736655524 cycles
+           [    0.000004] clocksource: kvm-clock: mask: 0xffffffffffffffff max_cycles: 0x1cd42e4dffb, max_idle_ns: 881590591483 ns
+           [    0.007355] Booting paravirtualized kernel on KVM
+           [    0.213538] clocksource: Switched to clocksource kvm-clock
+         So, we test whether the file
+         /sys/devices/system/clocksource/clocksource0/available_clocksource
+         contains the word 'kvm-clock'.  */
+      char buf[4096 + 1];
+      int fd = open ("/sys/devices/system/clocksource/clocksource0/available_clocksource", O_RDONLY);
+      if (fd >= 0)
+        {
+          int n = read (fd, buf, sizeof (buf) - 1);
+          close (fd);
+          if (n > 0)
+            {
+              buf[n] = '\0';
+              char *saveptr;
+              char *word;
+              for (word = strtok_r (buf, " \n", &saveptr);
+                   word != NULL;
+                   word = strtok_r (NULL, " \n", &saveptr))
+                {
+                  if (strcmp (word, "kvm-clock") == 0)
+                    return true;
+                }
+            }
+        }
+    }
+#endif
+
+  return false;
+}
+
+/* This function returns the number of CPUs in the current system, assuming
+   it is Linux.  */
+static int
+num_cpus (void)
+{
+#ifdef __linux__
+  /* We could use sysconf (_SC_NPROCESSORS_CONF), which on glibc and musl libc
+     is implemented through sched_getaffinity().  But there are some
+     complications; see nproc.c.  It's simpler to parse /proc/cpuinfo.
+     More precisely, it's sufficient to count the number of blank lines in
+     /proc/cpuinfo.  */
+  char buf[4096];
+  int fd = open ("/proc/cpuinfo", O_RDONLY);
+  if (fd >= 0)
+    {
+      unsigned int blank_lines = 0;
+      bool last_char_was_newline = false;
+      for (;;)
+        {
+          int n = read (fd, buf, sizeof (buf));
+          if (n <= 0)
+            break;
+          int i;
+          for (i = 0; i < n; i++)
+            {
+              if (last_char_was_newline && buf[i] == '\n')
+                blank_lines++;
+              last_char_was_newline = (buf[i] == '\n');
+            }
+        }
+      close (fd);
+      if (blank_lines > 0)
+        return blank_lines;
+    }
+#endif
+
+  return 1;
+}