[Xen-changelog] [xen-unstable] tools: readnote: Add bzImage kernel support

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User Xuesen Guo <Xuesen.Guo@xxxxxxxxxxxxxxxxxxxxx>
# Date 1339166034 -3600
# Node ID 4d40d7a4c6f1fcdb65558adb5b85e48e4600c190
# Parent  9d1fd58ff602f5f7b8a50ea3866adfd8668e0285
tools: readnote: Add bzImage kernel support

Add the check of bzImage kernel and make it work
with RHEL 6 big zImage kernel

Signed-off-by: Xuesen Guo <Xuesen.Guo@xxxxxxxxxxxxxxxxxxxxx>
Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Committed-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
---


diff -r 9d1fd58ff602 -r 4d40d7a4c6f1 tools/xcutils/readnotes.c
--- a/tools/xcutils/readnotes.c Fri Jun 08 15:26:01 2012 +0100
+++ b/tools/xcutils/readnotes.c Fri Jun 08 15:33:54 2012 +0100
@@ -18,6 +18,48 @@
 
 static xc_interface *xch;
 
+/* According to the implemation of xc_dom_probe_bzimage_kernel() function */
+/* We add support of bzImage kernel */
+/* Copied from tools/libxc/xc_doom_bzImageloader.c */
+struct setup_header {
+       uint8_t  _pad0[0x1f1];  /* skip uninteresting stuff */
+       uint8_t  setup_sects;
+       uint16_t root_flags;
+       uint32_t syssize;
+       uint16_t ram_size;
+       uint16_t vid_mode;
+       uint16_t root_dev;
+       uint16_t boot_flag;
+       uint16_t jump;
+       uint32_t header;
+#define HDR_MAGIC  "HdrS"
+#define HDR_MAGIC_SZ 4
+       uint16_t version;
+#define VERSION(h,l) (((h)<<8) | (l))
+       uint32_t realmode_swtch;
+       uint16_t start_sys;
+       uint16_t kernel_version;
+       uint8_t  type_of_loader;
+       uint8_t  loadflags;
+       uint16_t setup_move_size;
+       uint32_t code32_start;
+       uint32_t ramdisk_image;
+       uint32_t ramdisk_size;
+       uint32_t bootsect_kludge;
+       uint16_t heap_end_ptr;
+       uint16_t _pad1;
+       uint32_t cmd_line_ptr;
+       uint32_t initrd_addr_max;
+       uint32_t kernel_alignment;
+       uint8_t  relocatable_kernel;
+       uint8_t  _pad2[3];
+       uint32_t cmdline_size;
+       uint32_t hardware_subarch;
+       uint64_t hardware_subarch_data;
+       uint32_t payload_offset;
+       uint32_t payload_length;
+} __attribute__((packed));
+
 static void print_string_note(const char *prefix, struct elf_binary *elf,
                              const elf_note *note)
 {
@@ -131,6 +173,9 @@ int main(int argc, char **argv)
        const elf_shdr *shdr;
        int notes_found = 0;
 
+       struct setup_header *hdr;
+       uint64_t payload_offset, payload_length;
+
        if (argc != 2)
        {
                fprintf(stderr, "Usage: readnotes <elfimage>\n");
@@ -159,13 +204,45 @@ int main(int argc, char **argv)
                fprintf(stderr, "Unable to map %s: %s\n", f, strerror(errno));
                return 1;
        }
-       size = st.st_size;
+       
+       /* Check the magic of bzImage kernel */
+       hdr = (struct setup_header *)image;
+       if ( memcmp(&hdr->header, HDR_MAGIC, HDR_MAGIC_SZ) == 0 )
+       {
+               if ( hdr->version < VERSION(2,8) )
+               {
+                       printf("%s: boot protocol too old (%04x)", 
__FUNCTION__, hdr->version);
+                       return 1;
+               }
 
-       usize = xc_dom_check_gzip(xch, image, st.st_size);
+               /* upcast to 64 bits to avoid overflow */
+               /* setup_sects is u8 and so cannot overflow */
+               payload_offset = (hdr->setup_sects + 1) * 512;
+               payload_offset += hdr->payload_offset;
+               payload_length = hdr->payload_length;
+               
+               if ( payload_offset >= st.st_size )
+               {
+                       printf("%s: payload offset overflow", __FUNCTION__);
+                       return 1;
+               }
+               if ( (payload_offset + payload_length) > st.st_size )
+               {
+                       printf("%s: payload length overflow", __FUNCTION__);
+                       return 1;
+               }
+
+               image = image + payload_offset;
+               size = payload_length;
+       } else {
+               size = st.st_size;
+       }
+
+       usize = xc_dom_check_gzip(xch, image, size);
        if (usize)
        {
                tmp = malloc(usize);
-               xc_dom_do_gunzip(xch, image, st.st_size, tmp, usize);
+               xc_dom_do_gunzip(xch, image, size, tmp, usize);
                image = tmp;
                size = usize;
        }

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