Add the "search for other bootloaders" euristic.

When looking for the place to install GRUB we need to search for
the drives/partitions that dont have other bootloaders in the
first 512 bytes.  This will be done by means of functions that
specifically look for boot loaders.  ATM there is only one
function that will allow an installation allways.  In the futre
we hope to have user defined funcitons for specific bootloaders.

2 files changed, 63 insertions, 20 deletions

diff --git a/plugins/grub/grub.py b/plugins/grub/grub.py
index 4f75b49..166be55 100644
--- a/plugins/grub/grub.py
+++ b/plugins/grub/grub.py
@@ -49,11 +49,11 @@ class Grub(Plugin):
         # found.
         self.grub_dir_parts = []
 
-        # The partitions where the grub binary is found in the first 446 bytes.
-        self.grub_bin_parts = []
+        # The partitions where grub binary will be installed (first 446 bytes).
+        self.install_grub_parts = []
 
-        # The devs where the grub binary is found in the first 446 bytes.
-        self.grub_bin_devs = []
+        # The devs where grub binary will be installed (first 446 bytes).
+        self.install_grub_devs = []
 
         # Initialize our list of related issues.
         self.issue_grub_dir = SimpleIssue(self.name, "Missing grub dir or " \
@@ -92,32 +92,50 @@ class Grub(Plugin):
                                 "searching partition %s. Error: %s." % \
                                 (part.path(), e) ,origin = self)
 
+
+            # We will search the devices and disks for the ones in which we can
+            # install the grub binary.  There are three possibilities when
+            # making this decision:
+            # 1. We find a grub in the mbr:  In this case we want to add it to
+            #       add it to the list because we will be reinstalling it.
+            # 2. We find no bootloader present:  In this case we also want
+            #       to add it because it wont hurt to have grub on a secto
+            #       that is not used anyway.  And there is a possibility that
+            #       installing it will fix the problem.
+            # 3. We find another bootloader:  In this case the default
+            #       behavior is to leave it alone.
+            # There will exist two override statements:
+            # 1. Dont ignore devices with other bootloaders.
+            # 2. Pass a list of devices in which the user wants to install the
+            #       grub.  In which case all checks are ignored.
+            #
             # We must search in all the possible partitions and devices for the
             # grub binary.
-            self._reporting.info("Searching for the grub stage1 image.", \
-                    origin = self)
+            self._reporting.info("Searching for locations in which to " \
+                    "install grub.", origin = self)
             for (dev, parts) in self.devices.iteritems():
 
-                # We look for grub in the device
+                # We see if we can install grub in device.
                 try:
-                    if grubUtils.grub_bin_in_dev(Dname(dev)):
-                        self._reporting.info("Found grub stage1 image in %s " \
-                                "device" % Dname.asPath(dev), origin = self)
-                        self.grub_bin_devs.append(grubUtils.Dname(dev))
+                    if grubUtils.other_bootloader_present(Dname(dev)):
+                        self._reporting.info("Found no other bootloader in " \
+                                "%s device." % Dname.asPath(dev), \
+                                origin = self)
+                        self.install_grub_devs.append(grubUtils.Dname(dev))
 
                 except Exception, e:
                     self._reporting.error("There was an error searching for " \
                             "the grub images in device %s. Error %s." % \
                             (Dname.asPath(dev), e), origin = self)
 
-                # No we look for the grub in the partitions.
+                # Now we see if we can install in the partitions.
                 for part in parts:
                     try:
-                        if grubUtils.grub_bin_in_part(Dname(part)):
-                            self._reporting.info("Found grub stage1 image " \
-                                    "in %s partition" % Dname.asPath(dev), \
-                                    origin = self)
-                            self.grub_bin_parts.append(Dname(part))
+                        if grubUtils.other_bootloader_present(Dname(part)):
+                        self._reporting.info("Found no other bootloader in " \
+                                "%s partition." % Dname.asPath(part), \
+                                origin = self)
+                            self.install_grub_parts.append(Dname(part))
 
                     except Exception, e:
                         self._reporting.error("There was an error searching " \
@@ -160,16 +178,16 @@ class Grub(Plugin):
         # At this point we know that we are going to reinstall the grub.  We
         # inform the user about the state of the stage1 in the partitions but
         # we do nothing else with this information.
-        if len(self.grub_bin_parts) == 0:
+        if len(self.install_grub_parts) == 0:
             self._reporting.info("No valid grub image was found in any " \
                     "partition in the system.", origin = self)
-        if len(self.grub_bin_devs) == 0:
+        if len(self.install_grub_devs) == 0:
             self._reporting.info("No valid grub image was found in any " \
                     "device in the system.", origin = self)
 
         # Only if there is no recognizable image do we consider it to be
         # an issue.
-        if len(self.grub_bin_parts) == 0 and len(self.grub_bin_devs) == 0:
+        if len(self.install_grub_parts) == 0 and len(self.install_grub_devs) == 0:
             self.issue_grub_image.set(checked = True, happened = True,
                     reporting = self._reporting, origin = self)
         else:
diff --git a/plugins/grub/grubUtils.py b/plugins/grub/grubUtils.py
index 6a5578f..54a5083 100644
--- a/plugins/grub/grubUtils.py
+++ b/plugins/grub/grubUtils.py
@@ -233,6 +233,31 @@ def part_unmount(part, opts=None):
     else:
         return True
 
+
+#
+# There will be the possitility of installing the grub in all partitions
+# that dont have a boot loader (This will hopefully be default behavior).
+# For this purpose we must test to see if there are boot loaders in the
+# device.
+#
+# The idea here is to have people scream about firstaidkit messing their
+# other bootloaders up and creating new tests as needed.
+#
+# FIXME:If this function gets too big, might want to make another file.
+def other_bootloader_present(dev):
+    # Will allways say that no bootloader is present.
+    def none_grub(dev):
+        return False
+
+    # We will have the list of all the tests in the tests variable.
+    tests = {none_grub}
+
+    for test in tests:
+        if test(dev):
+            return True
+
+    return False
+
 # The Strings contained in the grub stage one:
 stage1strings = ["GRUB", "Geom", "Hard", "Disk", "Read", "Error"]