New APIs for guest inspection.

This commit converts (some of) the Perl inspection code to C and
makes it available through core APIs.  The new APIs are:

inspect-os        - Does the inspection, returns list of OSes
inspect-get-*     - Get results of the inspection

where '*' is one of:

  type            - 'windows' or 'linux'
  distro          - Linux distro
  arch            - architecture
  product-name    - long product name string
  major-version
  minor-version   - major.minor version of OS
  mountpoints     - get a list of the mountpoints
  filesystems     - get all filesystems associated with the OS

This works for all existing supported Linux and Windows OSes.

1 files changed, 1017 insertions, 0 deletions

diff --git a/src/inspect.c b/src/inspect.c
index d19e23b6..d1bb7bb4 100644
--- a/src/inspect.c
+++ b/src/inspect.c
@@ -28,8 +28,11 @@
 
 #include <pcre.h>
 #include <magic.h>
+#include <hivex.h>
+#include <augeas.h>
 
 #include "ignore-value.h"
+#include "xstrtol.h"
 
 #include "guestfs.h"
 #include "guestfs-internal.h"
@@ -44,6 +47,14 @@
 static pcre *re_file_elf;
 static pcre *re_file_win64;
 static pcre *re_elf_ppc64;
+static pcre *re_fedora;
+static pcre *re_rhel_old;
+static pcre *re_rhel;
+static pcre *re_rhel_no_minor;
+static pcre *re_debian;
+static pcre *re_aug_seq;
+static pcre *re_xdev;
+static pcre *re_windows_version;
 
 static void compile_regexps (void) __attribute__((constructor));
 static void
@@ -64,6 +75,17 @@ compile_regexps (void)
   COMPILE (re_file_elf,
            "ELF.*(?:executable|shared object|relocatable), (.+?),", 0);
   COMPILE (re_elf_ppc64, "64.*PowerPC", 0);
+  COMPILE (re_fedora, "Fedora release (\\d+)", 0);
+  COMPILE (re_rhel_old,
+           "(?:Red Hat Enterprise Linux|CentOS|Scientific Linux).*release (\\d+).*Update (\\d+)", 0);
+  COMPILE (re_rhel,
+           "(?:Red Hat Enterprise Linux|CentOS|Scientific Linux).*release (\\d+)\\.(\\d+)", 0);
+  COMPILE (re_rhel_no_minor,
+           "(?:Red Hat Enterprise Linux|CentOS|Scientific Linux).*release (\\d+)", 0);
+  COMPILE (re_debian, "(\\d+)\\.(\\d+)", 0);
+  COMPILE (re_aug_seq, "/\\d+$", 0);
+  COMPILE (re_xdev, "^/dev/(?:h|s|v|xv)d([a-z]\\d*)$", 0);
+  COMPILE (re_windows_version, "^(\\d+)\\.(\\d+)", 0);
 }
 
 /* Match a regular expression which contains no captures.  Returns
@@ -111,6 +133,29 @@ match1 (guestfs_h *g, const char *str, const pcre *re)
   return safe_strndup (g, &str[vec[2]], vec[3]-vec[2]);
 }
 
+/* Match a regular expression which contains exactly two captures. */
+static int
+match2 (guestfs_h *g, const char *str, const pcre *re, char **ret1, char **ret2)
+{
+  size_t len = strlen (str);
+  int vec[30], r;
+
+  r = pcre_exec (re, NULL, str, len, 0, 0, vec, 30);
+  if (r == PCRE_ERROR_NOMATCH)
+    return 0;
+  if (r != 3) {
+    /* Internal error -- should not happen. */
+    fprintf (stderr, "libguestfs: %s: %s: internal error: pcre_exec returned unexpected error code %d when matching against the string \"%s\"\n",
+             __FILE__, __func__, r, str);
+    return 0;
+  }
+
+  *ret1 = safe_strndup (g, &str[vec[2]], vec[3]-vec[2]);
+  *ret2 = safe_strndup (g, &str[vec[4]], vec[5]-vec[4]);
+
+  return 1;
+}
+
 /* Convert output from 'file' command on ELF files to the canonical
  * architecture string.  Caller must free the result.
  */
@@ -278,3 +323,975 @@ guestfs__file_architecture (guestfs_h *g, const char *path)
   free (elf_arch);
   return ret;                   /* caller frees */
 }
+
+/* The main inspection code. */
+static int feature_available (guestfs_h *g, const char *feature);
+static void free_string_list (char **);
+static int check_for_filesystem_on (guestfs_h *g, const char *device);
+
+char **
+guestfs__inspect_os (guestfs_h *g)
+{
+  /* Remove any information previously stored in the handle. */
+  guestfs___free_inspect_info (g);
+
+  if (guestfs_umount_all (g) == -1)
+    return NULL;
+
+  /* Iterate over all possible devices.  Try to mount each
+   * (read-only).  Examine ones which contain filesystems and add that
+   * information to the handle.
+   */
+  /* Look to see if any devices directly contain filesystems (RHBZ#590167). */
+  char **devices;
+  devices = guestfs_list_devices (g);
+  if (devices == NULL)
+    return NULL;
+
+  size_t i;
+  for (i = 0; devices[i] != NULL; ++i) {
+    if (check_for_filesystem_on (g, devices[i]) == -1) {
+      free_string_list (devices);
+      guestfs___free_inspect_info (g);
+      return NULL;
+    }
+  }
+  free_string_list (devices);
+
+  /* Look at all partitions. */
+  char **partitions;
+  partitions = guestfs_list_partitions (g);
+  if (partitions == NULL) {
+    guestfs___free_inspect_info (g);
+    return NULL;
+  }
+
+  for (i = 0; partitions[i] != NULL; ++i) {
+    if (check_for_filesystem_on (g, partitions[i]) == -1) {
+      free_string_list (partitions);
+      guestfs___free_inspect_info (g);
+      return NULL;
+    }
+  }
+  free_string_list (partitions);
+
+  /* Look at all LVs. */
+  if (feature_available (g, "lvm2")) {
+    char **lvs;
+    lvs = guestfs_lvs (g);
+    if (lvs == NULL) {
+      guestfs___free_inspect_info (g);
+      return NULL;
+    }
+
+    for (i = 0; lvs[i] != NULL; ++i) {
+      if (check_for_filesystem_on (g, lvs[i]) == -1) {
+        free_string_list (lvs);
+        guestfs___free_inspect_info (g);
+        return NULL;
+      }
+    }
+    free_string_list (lvs);
+  }
+
+  /* At this point we have, in the handle, a list of all filesystems
+   * found and data about each one.  Now we assemble the list of
+   * filesystems which are root devices and return that to the user.
+   */
+  size_t count = 0;
+  for (i = 0; i < g->nr_fses; ++i)
+    if (g->fses[i].is_root)
+      count++;
+
+  char **ret = calloc (count+1, sizeof (char *));
+  if (ret == NULL) {
+    perrorf (g, "calloc");
+    guestfs___free_inspect_info (g);
+    return NULL;
+  }
+
+  count = 0;
+  for (i = 0; i < g->nr_fses; ++i) {
+    if (g->fses[i].is_root) {
+      ret[count] = safe_strdup (g, g->fses[i].device);
+      count++;
+    }
+  }
+  ret[count] = NULL;
+
+  return ret;
+}
+
+void
+guestfs___free_inspect_info (guestfs_h *g)
+{
+  size_t i;
+  for (i = 0; i < g->nr_fses; ++i) {
+    free (g->fses[i].device);
+    free (g->fses[i].product_name);
+    free (g->fses[i].arch);
+    size_t j;
+    for (j = 0; j < g->fses[i].nr_fstab; ++j) {
+      free (g->fses[i].fstab[j].device);
+      free (g->fses[i].fstab[j].mountpoint);
+    }
+    free (g->fses[i].fstab);
+  }
+  free (g->fses);
+  g->nr_fses = 0;
+  g->fses = NULL;
+}
+
+static void
+free_string_list (char **argv)
+{
+  size_t i;
+  for (i = 0; argv[i] != NULL; ++i)
+    free (argv[i]);
+  free (argv);
+}
+
+/* In the Perl code this is a public function. */
+static int
+feature_available (guestfs_h *g, const char *feature)
+{
+  /* If there's an error we should ignore it, so to do that we have to
+   * temporarily replace the error handler with a null one.
+   */
+  guestfs_error_handler_cb old_error_cb = g->error_cb;
+  g->error_cb = NULL;
+
+  const char *groups[] = { feature, NULL };
+  int r = guestfs_available (g, (char * const *) groups);
+
+  g->error_cb = old_error_cb;
+
+  return r == 0 ? 1 : 0;
+}
+
+/* Find out if 'device' contains a filesystem.  If it does, add
+ * another entry in g->fses.
+ */
+static int check_filesystem (guestfs_h *g, const char *device);
+static int check_linux_root (guestfs_h *g, struct inspect_fs *fs);
+static int check_fstab (guestfs_h *g, struct inspect_fs *fs);
+static int check_windows_root (guestfs_h *g, struct inspect_fs *fs);
+static int check_windows_arch (guestfs_h *g, struct inspect_fs *fs,
+                               const char *systemroot);
+static int check_windows_registry (guestfs_h *g, struct inspect_fs *fs,
+                                   const char *systemroot);
+static char *resolve_windows_path_silently (guestfs_h *g, const char *);
+static int extend_fses (guestfs_h *g);
+static int parse_unsigned_int (guestfs_h *g, const char *str);
+static int add_fstab_entry (guestfs_h *g, struct inspect_fs *fs,
+                            const char *spec, const char *mp);
+static char *resolve_fstab_device (guestfs_h *g, const char *spec);
+
+static int
+check_for_filesystem_on (guestfs_h *g, const char *device)
+{
+  /* Get vfs-type in order to check if it's a Linux(?) swap device.
+   * If there's an error we should ignore it, so to do that we have to
+   * temporarily replace the error handler with a null one.
+   */
+  guestfs_error_handler_cb old_error_cb = g->error_cb;
+  g->error_cb = NULL;
+  char *vfs_type = guestfs_vfs_type (g, device);
+  g->error_cb = old_error_cb;
+
+  int is_swap = vfs_type && STREQ (vfs_type, "swap");
+
+  if (g->verbose)
+    fprintf (stderr, "check_for_filesystem_on: %s (%s)\n",
+             device, vfs_type ? vfs_type : "failed to get vfs type");
+
+  if (is_swap) {
+    free (vfs_type);
+    if (extend_fses (g) == -1)
+      return -1;
+    g->fses[g->nr_fses-1].is_swap = 1;
+    return 0;
+  }
+
+  /* Try mounting the device.  As above, ignore errors. */
+  g->error_cb = NULL;
+  int r = guestfs_mount_ro (g, device, "/");
+  if (r == -1 && vfs_type && STREQ (vfs_type, "ufs")) /* Hack for the *BSDs. */
+    r = guestfs_mount_vfs (g, "ro,ufstype=ufs2", "ufs", device, "/");
+  free (vfs_type);
+  g->error_cb = old_error_cb;
+  if (r == -1)
+    return 0;
+
+  /* Do the rest of the checks. */
+  r = check_filesystem (g, device);
+
+  /* Unmount the filesystem. */
+  if (guestfs_umount_all (g) == -1)
+    return -1;
+
+  return r;
+}
+
+static int
+check_filesystem (guestfs_h *g, const char *device)
+{
+  if (extend_fses (g) == -1)
+    return -1;
+
+  struct inspect_fs *fs = &g->fses[g->nr_fses-1];
+
+  fs->device = safe_strdup (g, device);
+  fs->is_mountable = 1;
+
+  /* Grub /boot? */
+  if (guestfs_is_file (g, "/grub/menu.lst") > 0 ||
+      guestfs_is_file (g, "/grub/grub.conf") > 0)
+    fs->content = FS_CONTENT_LINUX_BOOT;
+  /* Linux root? */
+  else if (guestfs_is_dir (g, "/etc") > 0 &&
+           guestfs_is_dir (g, "/bin") > 0 &&
+           guestfs_is_file (g, "/etc/fstab") > 0) {
+    fs->is_root = 1;
+    fs->content = FS_CONTENT_LINUX_ROOT;
+    if (check_linux_root (g, fs) == -1)
+      return -1;
+  }
+  /* Linux /usr/local? */
+  else if (guestfs_is_dir (g, "/etc") > 0 &&
+           guestfs_is_dir (g, "/bin") > 0 &&
+           guestfs_is_dir (g, "/share") > 0 &&
+           guestfs_exists (g, "/local") == 0 &&
+           guestfs_is_file (g, "/etc/fstab") == 0)
+    fs->content = FS_CONTENT_LINUX_USR_LOCAL;
+  /* Linux /usr? */
+  else if (guestfs_is_dir (g, "/etc") > 0 &&
+           guestfs_is_dir (g, "/bin") > 0 &&
+           guestfs_is_dir (g, "/share") > 0 &&
+           guestfs_exists (g, "/local") > 0 &&
+           guestfs_is_file (g, "/etc/fstab") == 0)
+    fs->content = FS_CONTENT_LINUX_USR;
+  /* Linux /var? */
+  else if (guestfs_is_dir (g, "/log") > 0 &&
+           guestfs_is_dir (g, "/run") > 0 &&
+           guestfs_is_dir (g, "/spool") > 0)
+    fs->content = FS_CONTENT_LINUX_VAR;
+  /* Windows root? */
+  else if (guestfs_is_file (g, "/AUTOEXEC.BAT") > 0 ||
+           guestfs_is_file (g, "/autoexec.bat") > 0 ||
+           guestfs_is_dir (g, "/Program Files") > 0 ||
+           guestfs_is_dir (g, "/WINDOWS") > 0 ||
+           guestfs_is_dir (g, "/Windows") > 0 ||
+           guestfs_is_dir (g, "/windows") > 0 ||
+           guestfs_is_dir (g, "/WIN32") > 0 ||
+           guestfs_is_dir (g, "/Win32") > 0 ||
+           guestfs_is_dir (g, "/WINNT") > 0 ||
+           guestfs_is_file (g, "/boot.ini") > 0 ||
+           guestfs_is_file (g, "/ntldr") > 0) {
+    fs->is_root = 1;
+    fs->content = FS_CONTENT_WINDOWS_ROOT;
+    if (check_windows_root (g, fs) == -1)
+      return -1;
+  }
+
+  return 0;
+}
+
+/* The currently mounted device is known to be a Linux root.  Try to
+ * determine from this the distro, version, etc.  Also parse
+ * /etc/fstab to determine the arrangement of mountpoints and
+ * associated devices.
+ */
+static int
+check_linux_root (guestfs_h *g, struct inspect_fs *fs)
+{
+  fs->type = OS_TYPE_LINUX;
+
+  if (guestfs_exists (g, "/etc/redhat-release") > 0) {
+    fs->distro = OS_DISTRO_REDHAT_BASED; /* Something generic Red Hat-like. */
+
+    char **product_name = guestfs_head_n (g, 1, "/etc/redhat-release");
+    if (product_name == NULL)
+      return -1;
+    if (product_name[0] == NULL) {
+      error (g, "/etc/redhat-release file is empty");
+      free_string_list (product_name);
+      return -1;
+    }
+
+    /* Note that this string becomes owned by the handle and will
+     * be freed by guestfs___free_inspect_info.
+     */
+    fs->product_name = product_name[0];
+    free (product_name);
+
+    char *major, *minor;
+    if ((major = match1 (g, fs->product_name, re_fedora)) != NULL) {
+      fs->distro = OS_DISTRO_FEDORA;
+      fs->major_version = parse_unsigned_int (g, major);
+      free (major);
+      if (fs->major_version == -1)
+        return -1;
+    }
+    else if (match2 (g, fs->product_name, re_rhel_old, &major, &minor) ||
+             match2 (g, fs->product_name, re_rhel, &major, &minor)) {
+      fs->distro = OS_DISTRO_RHEL;
+      fs->major_version = parse_unsigned_int (g, major);
+      free (major);
+      if (fs->major_version == -1) {
+        free (minor);
+        return -1;
+      }
+      fs->minor_version = parse_unsigned_int (g, minor);
+      free (minor);
+      if (fs->minor_version == -1)
+        return -1;
+    }
+    else if ((major = match1 (g, fs->product_name, re_rhel_no_minor)) != NULL) {
+      fs->distro = OS_DISTRO_RHEL;
+      fs->major_version = parse_unsigned_int (g, major);
+      free (major);
+      if (fs->major_version == -1)
+        return -1;
+      fs->minor_version = 0;
+    }
+  }
+  else if (guestfs_exists (g, "/etc/debian_version") > 0) {
+    fs->distro = OS_DISTRO_DEBIAN;
+
+    char **product_name = guestfs_head_n (g, 1, "/etc/debian_version");
+    if (product_name == NULL)
+      return -1;
+    if (product_name[0] == NULL) {
+      error (g, "/etc/debian_version file is empty");
+      free_string_list (product_name);
+      return -1;
+    }
+
+    /* Note that this string becomes owned by the handle and will
+     * be freed by guestfs___free_inspect_info.
+     */
+    fs->product_name = product_name[0];
+    free (product_name);
+
+    char *major, *minor;
+    if (match2 (g, fs->product_name, re_debian, &major, &minor)) {
+      fs->major_version = parse_unsigned_int (g, major);
+      free (major);
+      if (fs->major_version == -1) {
+        free (minor);
+        return -1;
+      }
+      fs->minor_version = parse_unsigned_int (g, minor);
+      free (minor);
+      if (fs->minor_version == -1)
+        return -1;
+    }
+  }
+
+  /* Determine the architecture. */
+  const char *binaries[] =
+    { "/bin/bash", "/bin/ls", "/bin/echo", "/bin/rm", "/bin/sh" };
+  size_t i;
+  for (i = 0; i < sizeof binaries / sizeof binaries[0]; ++i) {
+    if (guestfs_is_file (g, binaries[i]) > 0) {
+      /* Ignore errors from file_architecture call. */
+      guestfs_error_handler_cb old_error_cb = g->error_cb;
+      g->error_cb = NULL;
+      char *arch = guestfs_file_architecture (g, binaries[i]);
+      g->error_cb = old_error_cb;
+
+      if (arch) {
+        /* String will be owned by handle, freed by
+         * guestfs___free_inspect_info.
+         */
+        fs->arch = arch;
+        break;
+      }
+    }
+  }
+
+  /* We already know /etc/fstab exists because it's part of the test
+   * for Linux root above.  We must now parse this file to determine
+   * which filesystems are used by the operating system and how they
+   * are mounted.
+   * XXX What if !feature_available (g, "augeas")?
+   */
+  if (guestfs_aug_init (g, "/", AUG_NO_LOAD|AUG_SAVE_NOOP) == -1)
+    return -1;
+
+  /* Tell Augeas to only load /etc/fstab (thanks Raphaël Pinson). */
+  guestfs_aug_rm (g, "/augeas/load//incl[. != \"/etc/fstab\"]");
+  guestfs_aug_load (g);
+
+  int r = check_fstab (g, fs);
+  guestfs_aug_close (g);
+  if (r == -1)
+    return -1;
+
+  return 0;
+}
+
+static int
+check_fstab (guestfs_h *g, struct inspect_fs *fs)
+{
+  char **lines = guestfs_aug_ls (g, "/files/etc/fstab");
+  if (lines == NULL)
+    return -1;
+
+  if (lines[0] == NULL) {
+    error (g, "could not parse /etc/fstab or empty file");
+    free_string_list (lines);
+    return -1;
+  }
+
+  size_t i;
+  char augpath[256];
+  for (i = 0; lines[i] != NULL; ++i) {
+    /* Ignore comments.  Only care about sequence lines which
+     * match m{/\d+$}.
+     */
+    if (match (g, lines[i], re_aug_seq)) {
+      snprintf (augpath, sizeof augpath, "%s/spec", lines[i]);
+      char *spec = guestfs_aug_get (g, augpath);
+      if (spec == NULL) {
+        free_string_list (lines);
+        return -1;
+      }
+
+      snprintf (augpath, sizeof augpath, "%s/file", lines[i]);
+      char *mp = guestfs_aug_get (g, augpath);
+      if (mp == NULL) {
+        free_string_list (lines);
+        free (spec);
+        return -1;
+      }
+
+      int r = add_fstab_entry (g, fs, spec, mp);
+      free (spec);
+      free (mp);
+
+      if (r == -1) {
+        free_string_list (lines);
+        return -1;
+      }
+    }
+  }
+
+  free_string_list (lines);
+  return 0;
+}
+
+/* Add a filesystem and possibly a mountpoint entry for
+ * the root filesystem 'fs'.
+ *
+ * 'spec' is the fstab spec field, which might be a device name or a
+ * pseudodevice or 'UUID=...' or 'LABEL=...'.
+ *
+ * 'mp' is the mount point, which could also be 'swap' or 'none'.
+ */
+static int
+add_fstab_entry (guestfs_h *g, struct inspect_fs *fs,
+                 const char *spec, const char *mp)
+{
+  /* Ignore certain mountpoints. */
+  if (STRPREFIX (mp, "/dev/") ||
+      STREQ (mp, "/dev") ||
+      STRPREFIX (mp, "/media/") ||
+      STRPREFIX (mp, "/proc/") ||
+      STREQ (mp, "/proc") ||
+      STRPREFIX (mp, "/selinux/") ||
+      STREQ (mp, "/selinux") ||
+      STRPREFIX (mp, "/sys/") ||
+      STREQ (mp, "/sys"))
+    return 0;
+
+  /* Resolve UUID= and LABEL= to the actual device. */
+  char *device = NULL;
+  if (STRPREFIX (spec, "UUID="))
+    device = guestfs_findfs_uuid (g, &spec[5]);
+  else if (STRPREFIX (spec, "LABEL="))
+    device = guestfs_findfs_label (g, &spec[6]);
+  /* Resolve guest block device names. */
+  else if (spec[0] == '/')
+    device = resolve_fstab_device (g, spec);
+  /* Also ignore pseudo-devices completely, like spec == "tmpfs".
+   * If we haven't resolved the device successfully by this point,
+   * we don't care, just ignore it.
+   */
+  if (device == NULL)
+    return 0;
+
+  char *mountpoint = safe_strdup (g, mp);
+
+  /* Add this to the fstab entry in 'fs'.
+   * Note these are further filtered by guestfs_inspect_get_mountpoints
+   * and guestfs_inspect_get_filesystems.
+   */
+  size_t n = fs->nr_fstab + 1;
+  struct inspect_fstab_entry *p;
+
+  p = realloc (fs->fstab, n * sizeof (struct inspect_fstab_entry));
+  if (p == NULL) {
+    perrorf (g, "realloc");
+    free (device);
+    free (mountpoint);
+    return -1;
+  }
+
+  fs->fstab = p;
+  fs->nr_fstab = n;
+
+  /* These are owned by the handle and freed by guestfs___free_inspect_info. */
+  fs->fstab[n-1].device = device;
+  fs->fstab[n-1].mountpoint = mountpoint;
+
+  if (g->verbose)
+    fprintf (stderr, "fstab: device=%s mountpoint=%s\n", device, mountpoint);
+
+  return 0;
+}
+
+/* Resolve block device name to the libguestfs device name, eg.
+ * /dev/xvdb1 => /dev/vdb1.  This assumes that disks were added in the
+ * same order as they appear to the real VM, which is a reasonable
+ * assumption to make.  Return things like LV names unchanged (or
+ * anything we don't recognize).
+ */
+static char *
+resolve_fstab_device (guestfs_h *g, const char *spec)
+{
+  char **devices = guestfs_list_devices (g);
+  if (devices == NULL)
+    return NULL;
+
+  size_t count;
+  for (count = 0; devices[count] != NULL; count++)
+    ;
+
+  char *device = NULL;
+  char *a1 = match1 (g, spec, re_xdev);
+  if (a1) {
+    size_t i = a1[0] - 'a'; /* a1[0] is always [a-z] because of regex. */
+    if (i < count) {
+      size_t len = strlen (devices[i]) + strlen (a1) + 16;
+      device = safe_malloc (g, len);
+      snprintf (device, len, "%s%s", devices[i], &a1[1]);
+    }
+  } else {
+    /* Didn't match device pattern, return original spec unchanged. */
+    device = safe_strdup (g, spec);
+  }
+
+  free (a1);
+  free_string_list (devices);
+
+  return device;
+}
+
+/* XXX Handling of boot.ini in the Perl version was pretty broken.  It
+ * essentially didn't do anything for modern Windows guests.
+ * Therefore I've omitted all that code.
+ */
+static int
+check_windows_root (guestfs_h *g, struct inspect_fs *fs)
+{
+  fs->type = OS_TYPE_WINDOWS;
+  fs->distro = OS_DISTRO_WINDOWS;
+
+  /* Try to find Windows systemroot using some common locations. */
+  const char *systemroots[] =
+    { "/windows", "/winnt", "/win32", "/win" };
+  size_t i;
+  char *systemroot = NULL;
+  for (i = 0;
+       systemroot == NULL && i < sizeof systemroots / sizeof systemroots[0];
+       ++i) {
+    systemroot = resolve_windows_path_silently (g, systemroots[i]);
+  }
+
+  if (!systemroot) {
+    error (g, _("cannot resolve Windows %%SYSTEMROOT%%"));
+    return -1;
+  }
+
+  /* XXX There is a case for exposing systemroot and many variables
+   * from the registry through the libguestfs API.
+   */
+
+  if (g->verbose)
+    fprintf (stderr, "windows %%SYSTEMROOT%% = %s", systemroot);
+
+  if (check_windows_arch (g, fs, systemroot) == -1) {
+    free (systemroot);
+    return -1;
+  }
+
+  if (check_windows_registry (g, fs, systemroot) == -1) {
+    free (systemroot);
+    return -1;
+  }
+
+  free (systemroot);
+  return 0;
+}
+
+static int
+check_windows_arch (guestfs_h *g, struct inspect_fs *fs,
+                    const char *systemroot)
+{
+  size_t len = strlen (systemroot) + 32;
+  char cmd_exe[len];
+  snprintf (cmd_exe, len, "%s/system32/cmd.exe", systemroot);
+
+  char *cmd_exe_path = resolve_windows_path_silently (g, cmd_exe);
+  if (!cmd_exe_path)
+    return 0;
+
+  char *arch = guestfs_file_architecture (g, cmd_exe_path);
+  free (cmd_exe_path);
+
+  if (arch)
+    fs->arch = arch;        /* freed by guestfs___free_inspect_info */
+
+  return 0;
+}
+
+/* At the moment, pull just the ProductName and version numbers from
+ * the registry.  In future there is a case for making many more
+ * registry fields available to callers.
+ */
+static int
+check_windows_registry (guestfs_h *g, struct inspect_fs *fs,
+                        const char *systemroot)
+{
+  size_t len = strlen (systemroot) + 64;
+  char software[len];
+  snprintf (software, len, "%s/system32/config/software", systemroot);
+
+  char *software_path = resolve_windows_path_silently (g, software);
+  if (!software_path)
+    /* If the software hive doesn't exist, just accept that we cannot
+     * find product_name etc.
+     */
+    return 0;
+
+  int ret = -1;
+  hive_h *h = NULL;
+  hive_value_h *values = NULL;
+
+  char dir[] = "/tmp/winreg.XXXXXX";
+#define dir_len 18
+  if (mkdtemp (dir) == NULL) {
+    perrorf (g, "mkdtemp");
+    goto out;
+  }
+
+  char software_hive[dir_len + 16];
+  snprintf (software_hive, dir_len + 16, "%s/software", dir);
+
+  if (guestfs_download (g, software_path, software_hive) == -1)
+    goto out;
+
+  h = hivex_open (software_hive, g->verbose ? HIVEX_OPEN_VERBOSE : 0);
+  if (h == NULL) {
+    perrorf (g, "hivex_open");
+    goto out;
+  }
+
+  hive_node_h node = hivex_root (h);
+  const char *hivepath[] =
+    { "Microsoft", "Windows NT", "CurrentVersion" };
+  size_t i;
+  for (i = 0;
+       node != 0 && i < sizeof hivepath / sizeof hivepath[0];
+       ++i) {
+    node = hivex_node_get_child (h, node, hivepath[i]);
+  }
+
+  if (node == 0) {
+    perrorf (g, "hivex: cannot locate HKLM\\SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion");
+    goto out;
+  }
+
+  values = hivex_node_values (h, node);
+
+  for (i = 0; values[i] != 0; ++i) {
+    char *key = hivex_value_key (h, values[i]);
+    if (key == NULL) {
+      perrorf (g, "hivex_value_key");
+      goto out;
+    }
+
+    if (STRCASEEQ (key, "ProductName")) {
+      fs->product_name = hivex_value_string (h, values[i]);
+      if (!fs->product_name) {
+        perrorf (g, "hivex_value_string");
+        free (key);
+        goto out;
+      }
+    }
+    else if (STRCASEEQ (key, "CurrentVersion")) {
+      char *version = hivex_value_string (h, values[i]);
+      if (!version) {
+        perrorf (g, "hivex_value_string");
+        free (key);
+        goto out;
+      }
+      char *major, *minor;
+      if (match2 (g, version, re_windows_version, &major, &minor)) {
+        fs->major_version = parse_unsigned_int (g, major);
+        free (major);
+        if (fs->major_version == -1) {
+          free (minor);
+          free (key);
+          free (version);
+          goto out;
+        }
+        fs->minor_version = parse_unsigned_int (g, minor);
+        free (minor);
+        if (fs->minor_version == -1) {
+          free (key);
+          free (version);
+          return -1;
+        }
+      }
+
+      free (version);
+    }
+
+    free (key);
+  }
+
+  ret = 0;
+
+ out:
+  if (h) hivex_close (h);
+  free (values);
+  free (software_path);
+
+  /* Free up the temporary directory.  Note the directory name cannot
+   * contain shell meta-characters because of the way it was
+   * constructed above.
+   */
+  char cmd[dir_len + 16];
+  snprintf (cmd, dir_len + 16, "rm -rf %s", dir);
+  ignore_value (system (cmd));
+#undef dir_len
+
+  return ret;
+}
+
+static char *
+resolve_windows_path_silently (guestfs_h *g, const char *path)
+{
+  guestfs_error_handler_cb old_error_cb = g->error_cb;
+  g->error_cb = NULL;
+  char *ret = guestfs_case_sensitive_path (g, path);
+  g->error_cb = old_error_cb;
+  return ret;
+}
+
+static int
+extend_fses (guestfs_h *g)
+{
+  size_t n = g->nr_fses + 1;
+  struct inspect_fs *p;
+
+  p = realloc (g->fses, n * sizeof (struct inspect_fs));
+  if (p == NULL) {
+    perrorf (g, "realloc");
+    return -1;
+  }
+
+  g->fses = p;
+  g->nr_fses = n;
+
+  memset (&g->fses[n-1], 0, sizeof (struct inspect_fs));
+
+  return 0;
+}
+
+/* Parse small, unsigned ints, as used in version numbers. */
+static int
+parse_unsigned_int (guestfs_h *g, const char *str)
+{
+  long ret;
+  int r = xstrtol (str, NULL, 10, &ret, "");
+  if (r != LONGINT_OK) {
+    error (g, "could not parse integer in version number: %s", str);
+    return -1;
+  }
+  return ret;
+}
+
+static struct inspect_fs *
+search_for_root (guestfs_h *g, const char *root)
+{
+  if (g->nr_fses == 0) {
+    error (g, _("no inspection data: call guestfs_inspect_os first"));
+    return NULL;
+  }
+
+  size_t i;
+  struct inspect_fs *fs;
+  for (i = 0; i < g->nr_fses; ++i) {
+    fs = &g->fses[i];
+    if (fs->is_root && STREQ (root, fs->device))
+      return fs;
+  }
+
+  error (g, _("%s: root device not found: only call this function with a root device previously returned by guestfs_inspect_os"),
+         root);
+  return NULL;
+}
+
+char *
+guestfs__inspect_get_type (guestfs_h *g, const char *root)
+{
+  struct inspect_fs *fs = search_for_root (g, root);
+  if (!fs)
+    return NULL;
+
+  char *ret;
+  switch (fs->type) {
+  case OS_TYPE_LINUX: ret = safe_strdup (g, "linux"); break;
+  case OS_TYPE_WINDOWS: ret = safe_strdup (g, "windows"); break;
+  case OS_TYPE_UNKNOWN: default: ret = safe_strdup (g, "unknown"); break;
+  }
+
+  return ret;
+}
+
+char *
+guestfs__inspect_get_arch (guestfs_h *g, const char *root)
+{
+  struct inspect_fs *fs = search_for_root (g, root);
+  if (!fs)
+    return NULL;
+
+  return safe_strdup (g, fs->arch ? : "unknown");
+}
+
+char *
+guestfs__inspect_get_distro (guestfs_h *g, const char *root)
+{
+  struct inspect_fs *fs = search_for_root (g, root);
+  if (!fs)
+    return NULL;
+
+  char *ret;
+  switch (fs->distro) {
+  case OS_DISTRO_DEBIAN: ret = safe_strdup (g, "debian"); break;
+  case OS_DISTRO_FEDORA: ret = safe_strdup (g, "fedora"); break;
+  case OS_DISTRO_REDHAT_BASED: ret = safe_strdup (g, "redhat-based"); break;
+  case OS_DISTRO_RHEL: ret = safe_strdup (g, "rhel"); break;
+  case OS_DISTRO_WINDOWS: ret = safe_strdup (g, "windows"); break;
+  case OS_DISTRO_UNKNOWN: default: ret = safe_strdup (g, "unknown"); break;
+  }
+
+  return ret;
+}
+
+int 
+guestfs__inspect_get_major_version (guestfs_h *g, const char *root)
+{
+  struct inspect_fs *fs = search_for_root (g, root);
+  if (!fs)
+    return -1;
+
+  return fs->major_version;
+}
+
+int 
+guestfs__inspect_get_minor_version (guestfs_h *g, const char *root)
+{
+  struct inspect_fs *fs = search_for_root (g, root);
+  if (!fs)
+    return -1;
+
+  return fs->minor_version;
+}
+
+char *
+guestfs__inspect_get_product_name (guestfs_h *g, const char *root)
+{
+  struct inspect_fs *fs = search_for_root (g, root);
+  if (!fs)
+    return NULL;
+
+  return safe_strdup (g, fs->product_name ? : "unknown");
+}
+
+char **
+guestfs__inspect_get_mountpoints (guestfs_h *g, const char *root)
+{
+  struct inspect_fs *fs = search_for_root (g, root);
+  if (!fs)
+    return NULL;
+
+  char **ret;
+
+  /* If no fstab information (Windows) return just the root. */
+  if (fs->nr_fstab == 0) {
+    ret = calloc (3, sizeof (char *));
+    ret[0] = safe_strdup (g, "/");
+    ret[1] = safe_strdup (g, root);
+    ret[2] = NULL;
+    return ret;
+  }
+
+#define CRITERION fs->fstab[i].mountpoint[0] == '/'
+  size_t i, count = 0;
+  for (i = 0; i < fs->nr_fstab; ++i)
+    if (CRITERION)
+      count++;
+
+  /* Hashtables have 2N+1 entries. */
+  ret = calloc (2*count+1, sizeof (char *));
+  if (ret == NULL) {
+    perrorf (g, "calloc");
+    return NULL;
+  }
+
+  count = 0;
+  for (i = 0; i < fs->nr_fstab; ++i)
+    if (CRITERION) {
+      ret[2*count] = safe_strdup (g, fs->fstab[i].mountpoint);
+      ret[2*count+1] = safe_strdup (g, fs->fstab[i].device);
+      count++;
+    }
+#undef CRITERION
+
+  return ret;
+}
+
+char **
+guestfs__inspect_get_filesystems (guestfs_h *g, const char *root)
+{
+  struct inspect_fs *fs = search_for_root (g, root);
+  if (!fs)
+    return NULL;
+
+  char **ret;
+
+  /* If no fstab information (Windows) return just the root. */
+  if (fs->nr_fstab == 0) {
+    ret = calloc (2, sizeof (char *));
+    ret[0] = safe_strdup (g, root);
+    ret[1] = NULL;
+    return ret;
+  }
+
+  ret = calloc (fs->nr_fstab + 1, sizeof (char *));
+  if (ret == NULL) {
+    perrorf (g, "calloc");
+    return NULL;
+  }
+
+  size_t i;
+  for (i = 0; i < fs->nr_fstab; ++i)
+    ret[i] = safe_strdup (g, fs->fstab[i].device);
+
+  return ret;
+}