Re: [PATCH] grub-core/commands/probe.c: Add bootable parameter

[Vladimir 'phcoder' Serbinenko]

On Tue, Dec 12, 2017, 09:56 Carlo Caione <address@hidden> wrote:

From: Carlo Caione <address@hidden>

Sometimes we are interested in checking whether an msdos partition has
the boot flag set. Introduce a new parameter to the probe command to
check this.

Signed-off-by: Carlo Caione <address@hidden>
---
 grub-core/commands/probe.c | 18 ++++++++++++++++++
 grub-core/partmap/msdos.c  |  1 +
 include/grub/partition.h   |  3 +++
 3 files changed, 22 insertions(+)

diff --git a/grub-core/commands/probe.c b/grub-core/commands/probe.c
index cf2793e1d..22d1c5660 100644
--- a/grub-core/commands/probe.c
+++ b/grub-core/commands/probe.c
@@ -31,6 +31,7 @@
 #include <grub/env.h>
 #include <grub/extcmd.h>
 #include <grub/i18n.h>
+#include <grub/msdos_partition.h>

 GRUB_MOD_LICENSE ("GPLv3+");

@@ -45,6 +46,7 @@ static const struct grub_arg_option options[] =
     {"fs",             'f', 0, N_("Determine filesystem type."), 0, 0},
     {"fs-uuid",                'u', 0, N_("Determine filesystem UUID."), 0, 0},
     {"label",          'l', 0, N_("Determine filesystem label."), 0, 0},
+    {"bootable",       'b', 0, N_("Determine if bootable / active flag is set."), 0, 0},
     {0, 0, 0, 0, 0, 0}
   };

@@ -154,6 +156,22 @@ grub_cmd_probe (grub_extcmd_context_t ctxt, int argc, char **args)
       grub_device_close (dev);
       return GRUB_ERR_NONE;
     }
+  if (state[6].set)
+    {
+      const char *val = "none";
+      if (dev->disk &&
+          dev->disk->partition &&
+          dev->disk->partition->msdostype != GRUB_PC_PARTITION_TYPE_GPT_DISK &&
+          grub_strcmp (dev->disk->partition->partmap->name, "msdos") == 0)
+      if (dev->disk->partition->flag & 0x80)
+        val = "bootable";
+      if (state[0].set)
+        grub_env_set (state[0].arg, val);
+      else
+        grub_printf ("%s", val);
+      grub_device_close (dev);
+      return GRUB_ERR_NONE;
+    }
   grub_device_close (dev);
   return grub_error (GRUB_ERR_BAD_ARGUMENT, "unrecognised target");
 }
diff --git a/grub-core/partmap/msdos.c b/grub-core/partmap/msdos.c
index 6d4b455a1..6c13c6b8b 100644
--- a/grub-core/partmap/msdos.c
+++ b/grub-core/partmap/msdos.c
@@ -180,6 +180,7 @@ grub_partition_msdos_iterate (grub_disk_t disk,
          p.len = grub_le_to_cpu32 (e->length)
            << (disk->log_sector_size - GRUB_DISK_SECTOR_BITS);
          p.msdostype = e->type;
+         p.flag = e->flag;

part_msdos is too size-sensitive. Please don't add anything there. Just reread the sector with MBR or EBR in probing.

          grub_dprintf ("partition",
                        "partition %d: flag 0x%x, type 0x%x, start 0x%llx, len 0x%llx\n",
diff --git a/include/grub/partition.h b/include/grub/partition.h
index 7adb7ec6e..d450415e0 100644
--- a/include/grub/partition.h
+++ b/include/grub/partition.h
@@ -87,6 +87,9 @@ struct grub_partition
   /* The type of partition whne it's on MSDOS.
      Used for embedding detection.  */
   grub_uint8_t msdostype;
+
+  /* Partition flag */
+  grub_uint8_t flag;
 };

 grub_partition_t EXPORT_FUNC(grub_partition_probe) (struct grub_disk *disk,
--
2.14.1


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