1 files changed, 117 insertions, 0 deletions
diff --git a/grub-core/loader/i386/xen_file.c b/grub-core/loader/i386/xen_file.c
new file mode 100644
index 0000000..9af5d66
--- /dev/null
+++ b/grub-core/loader/i386/xen_file.c
@@ -0,0 +1,117 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2013  Free Software Foundation, Inc.
+ *
+ *  GRUB is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB 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 General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/xen_file.h>
+#include <grub/i386/linux.h>
+#include <grub/misc.h>
+
+#define XZ_MAGIC "\3757zXZ\0"
+
+grub_elf_t
+grub_xen_file (grub_file_t file)
+{
+  grub_elf_t elf;
+  struct linux_i386_kernel_header lh;
+  grub_file_t off_file;
+  grub_uint32_t payload_offset, payload_length;
+  grub_uint8_t magic[6];
+
+  elf = grub_elf_file (file, file->name);
+  if (elf)
+    return elf;
+  grub_errno = GRUB_ERR_NONE;
+
+  if (grub_file_seek (file, 0) == (grub_off_t) -1)
+    goto fail;
+
+  if (grub_file_read (file, &lh, sizeof (lh)) != sizeof (lh))
+    goto fail;
+
+  if (lh.boot_flag != grub_cpu_to_le16_compile_time (0xaa55)
+      || lh.header != grub_cpu_to_le32_compile_time (GRUB_LINUX_I386_MAGIC_SIGNATURE)
+      || grub_le_to_cpu16 (lh.version) < 0x0208)
+    {
+      grub_error (GRUB_ERR_BAD_OS, "version too old for xen boot");
+      return NULL;
+    }
+
+  payload_length = lh.payload_length;
+  payload_offset = (lh.setup_sects + 1) * 512
+    + lh.payload_offset;
+
+  if (payload_length < sizeof (magic))
+    {
+      grub_error (GRUB_ERR_BAD_OS, "payload too short");
+      return NULL;
+    }
+
+  grub_dprintf ("xen", "found bzimage payload 0x%llx-0x%llx\n",
+		(unsigned long long) payload_offset,
+		(unsigned long long) lh.payload_length);
+
+  grub_file_seek (file, payload_offset);
+
+  if (grub_file_read (file, &magic, sizeof (magic)) != sizeof (magic))
+    {
+      if (!grub_errno)
+	grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"),
+		    file->name);
+      goto fail;
+    }
+
+  /* Kernel suffixes xz payload with their uncompressed size.
+     Trim it.  */
+  if (grub_memcmp (magic, XZ_MAGIC, sizeof (XZ_MAGIC) - 1) == 0)
+    payload_length -= 4;
+  off_file = grub_file_offset_open (file, GRUB_FILE_TYPE_LINUX_KERNEL, payload_offset,
+				    payload_length);
+  if (!off_file)
+    goto fail;
+
+  elf = grub_elf_file (off_file, file->name);
+  if (elf)
+    return elf;
+  grub_file_offset_close (off_file);
+
+fail:
+  grub_error (GRUB_ERR_BAD_OS, "not xen image");
+  return NULL;
+}
+
+grub_err_t
+grub_xen_get_info (grub_elf_t elf, struct grub_xen_file_info * xi)
+{
+  grub_memset (xi, 0, sizeof (*xi));
+
+  if (grub_elf_is_elf64 (elf)
+      && elf->ehdr.ehdr64.e_machine
+      == grub_cpu_to_le16_compile_time (EM_X86_64)
+      && elf->ehdr.ehdr64.e_ident[EI_DATA] == ELFDATA2LSB)
+    {
+      xi->arch = GRUB_XEN_FILE_X86_64;
+      return grub_xen_get_info64 (elf, xi);
+    }
+  if (grub_elf_is_elf32 (elf)
+      && elf->ehdr.ehdr32.e_machine == grub_cpu_to_le16_compile_time (EM_386)
+      && elf->ehdr.ehdr32.e_ident[EI_DATA] == ELFDATA2LSB)
+    {
+      xi->arch = GRUB_XEN_FILE_I386;
+      return grub_xen_get_info32 (elf, xi);
+    }
+  return grub_error (GRUB_ERR_BAD_OS, "unknown ELF type");
+}