inspect: Optimize root filesystem check.

[libguestfs.git] / src / inspect.c

diff --git a/src/inspect.c b/src/inspect.c
index 3b2720c..2f543b5 100644 (file)
--- a/src/inspect.c
+++ b/src/inspect.c
@@ -257,13 +257,18 @@ check_filesystem (guestfs_h *g, const char *device)
   fs->device = safe_strdup (g, device);
   fs->is_mountable = 1;
 
+  /* Optimize some of the tests by avoiding multiple tests of the same thing. */
+  int is_dir_etc = guestfs_is_dir (g, "/etc") > 0;
+  int is_dir_bin = guestfs_is_dir (g, "/bin") > 0;
+  int is_dir_share = guestfs_is_dir (g, "/share") > 0;
+
   /* 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 &&
+  else if (is_dir_etc &&
+           is_dir_bin &&
            guestfs_is_file (g, "/etc/fstab") > 0) {
     fs->is_root = 1;
     fs->content = FS_CONTENT_LINUX_ROOT;
@@ -271,16 +276,16 @@ check_filesystem (guestfs_h *g, const char *device)
       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 &&
+  else if (is_dir_etc &&
+           is_dir_bin &&
+           is_dir_share &&
            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 &&
+  else if (is_dir_etc &&
+           is_dir_bin &&
+           is_dir_share &&
            guestfs_exists (g, "/local") > 0 &&
            guestfs_is_file (g, "/etc/fstab") == 0)
     fs->content = FS_CONTENT_LINUX_USR;
@@ -1526,4 +1531,29 @@ guestfs___match2 (guestfs_h *g, const char *str, const pcre *re,
   return 1;
 }
 
+/* Match a regular expression which contains exactly three captures. */
+int
+guestfs___match3 (guestfs_h *g, const char *str, const pcre *re,
+                  char **ret1, char **ret2, char **ret3)
+{
+  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 != 4) {
+    /* 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]);
+  *ret3 = safe_strndup (g, &str[vec[6]], vec[7]-vec[6]);
+
+  return 1;
+}
+
 #endif /* HAVE_PCRE */