domain builder: Implement bzip2 and LZMA loaders

Recent upstream kernels can be compressed using either gzip,
bzip2, or LZMA.  However, the PV kernel loader in Xen currently only
understands gzip, and will fail on the other two types.  The attached
patch implements kernel decompression for gzip, bzip2, and LZMA so
that kernels compressed with any of these methods can be launched.

Signed-off-by: Chris Lalancette <clalance@redhat.com>
Signed-off-by: Keir Fraser <keir.fraser@citrix.com>

1 files changed, 329 insertions, 57 deletions

diff --git a/tools/libxc/xc_dom_bzimageloader.c b/tools/libxc/xc_dom_bzimageloader.c
index 628cd7ddb4..4202ac79d7 100644
--- a/tools/libxc/xc_dom_bzimageloader.c
+++ b/tools/libxc/xc_dom_bzimageloader.c
@@ -11,6 +11,7 @@
  * written 2006 by Gerd Hoffmann <kraxel@suse.de>.
  * written 2007 by Jeremy Fitzhardinge <jeremy@xensource.com>
  * written 2008 by Ian Campbell <ijc@hellion.org.uk>
+ * written 2009 by Chris Lalancette <clalance@redhat.com>
  *
  */
 #include <stdio.h>
@@ -20,43 +21,289 @@
 #include "xg_private.h"
 #include "xc_dom.h"
 
+#if defined(HAVE_BZLIB)
+
+#include <bzlib.h>
+
+static int xc_try_bzip2_decode(
+    struct xc_dom_image *dom, void **blob, size_t *size)
+{
+    bz_stream stream;
+    int ret;
+    char *out_buf;
+    int retval = -1;
+    int outsize;
+    uint64_t total;
+
+    stream.bzalloc = NULL;
+    stream.bzfree = NULL;
+    stream.opaque = NULL;
+
+    ret = BZ2_bzDecompressInit(&stream, 0, 0);
+    if ( ret != BZ_OK )
+    {
+        xc_dom_printf("Error initting bz2 stream\n");
+        return -1;
+    }
+
+    /* sigh.  We don't know up-front how much memory we are going to need
+     * for the output buffer.  Allocate the output buffer to be equal
+     * the input buffer to start, and we'll realloc as needed.
+     */
+    outsize = dom->kernel_size;
+    out_buf = malloc(outsize);
+    if ( out_buf == NULL )
+    {
+        xc_dom_printf("Failed to alloc memory\n");
+        goto bzip2_cleanup;
+    }
+
+    stream.next_in = dom->kernel_blob;
+    stream.avail_in = dom->kernel_size;
+
+    stream.next_out = out_buf;
+    stream.avail_out = dom->kernel_size;
+
+    for ( ; ; )
+    {
+        ret = BZ2_bzDecompress(&stream);
+        if ( (stream.avail_out == 0) || (ret != BZ_OK) )
+        {
+            out_buf = realloc(out_buf, outsize * 2);
+            if ( out_buf == NULL )
+            {
+                xc_dom_printf("Failed to realloc memory\n");
+                break;
+            }
+
+            stream.next_out = out_buf + outsize;
+            stream.avail_out = (outsize * 2) - outsize;
+            outsize *= 2;
+        }
+
+        if ( ret != BZ_OK )
+        {
+            if ( ret == BZ_STREAM_END )
+            {
+                xc_dom_printf("Saw data stream end\n");
+                retval = 0;
+                break;
+            }
+            xc_dom_printf("BZIP error\n");
+        }
+    }
+
+    total = (stream.total_out_hi32 << 31) | stream.total_out_lo32;
+
+    xc_dom_printf("%s: BZIP2 decompress OK, 0x%zx -> 0x%lx\n",
+                  __FUNCTION__, *size, (long unsigned int) total);
+
+    *blob = out_buf;
+    *size = total;
+
+ bzip2_cleanup:
+    BZ2_bzDecompressEnd(&stream);
+
+    return retval;
+}
+
+#else /* !defined(HAVE_BZLIB) */
+
+static int xc_try_bzip2_decode(
+    struct xc_dom_image *dom, void **blob, size_t *size)
+{
+    xc_dom_printf("%s: LZMA decompress support unavailable\n",
+                  __FUNCTION__);
+    return -1;
+}
+
+#endif
+
+#if defined(HAVE_LZMA)
+
+#include <lzma.h>
+
+static uint64_t physmem(void)
+{
+    uint64_t ret = 0;
+    const long pagesize = sysconf(_SC_PAGESIZE);
+    const long pages = sysconf(_SC_PHYS_PAGES);
+
+    if ( (pagesize != -1) || (pages != -1) )
+    {
+        /*
+         * According to docs, pagesize * pages can overflow.
+         * Simple case is 32-bit box with 4 GiB or more RAM,
+         * which may report exactly 4 GiB of RAM, and "long"
+         * being 32-bit will overflow. Casting to uint64_t
+         * hopefully avoids overflows in the near future.
+         */
+        ret = (uint64_t)(pagesize) * (uint64_t)(pages);
+    }
+
+    return ret;
+}
+
+static int xc_try_lzma_decode(
+    struct xc_dom_image *dom, void **blob, size_t *size)
+{
+    lzma_stream stream = LZMA_STREAM_INIT;
+    lzma_ret ret;
+    lzma_action action = LZMA_RUN;
+    unsigned char *out_buf;
+    int retval = -1;
+    int outsize;
+    const char *msg;
+
+    ret = lzma_alone_decoder(&stream, physmem() / 3);
+    if ( ret != LZMA_OK )
+    {
+        xc_dom_printf("Failed to init lzma stream decoder\n");
+        return -1;
+    }
+
+    /* sigh.  We don't know up-front how much memory we are going to need
+     * for the output buffer.  Allocate the output buffer to be equal
+     * the input buffer to start, and we'll realloc as needed.
+     */
+    outsize = dom->kernel_size;
+    out_buf = malloc(outsize);
+    if ( out_buf == NULL )
+    {
+        xc_dom_printf("Failed to alloc memory\n");
+        goto lzma_cleanup;
+    }
+
+    stream.next_in = dom->kernel_blob;
+    stream.avail_in = dom->kernel_size;
+
+    stream.next_out = out_buf;
+    stream.avail_out = dom->kernel_size;
+
+    for ( ; ; )
+    {
+        ret = lzma_code(&stream, action);
+        if ( (stream.avail_out == 0) || (ret != LZMA_OK) )
+        {
+            out_buf = realloc(out_buf, outsize * 2);
+            if ( out_buf == NULL )
+            {
+                xc_dom_printf("Failed to realloc memory\n");
+                break;
+            }
+
+            stream.next_out = out_buf + outsize;
+            stream.avail_out = (outsize * 2) - outsize;
+            outsize *= 2;
+        }
+
+        if ( ret != LZMA_OK )
+        {
+            if ( ret == LZMA_STREAM_END )
+            {
+                xc_dom_printf("Saw data stream end\n");
+                retval = 0;
+                break;
+            }
+
+            switch ( ret )
+            {
+            case LZMA_MEM_ERROR:
+                msg = strerror(ENOMEM);
+                break;
+
+            case LZMA_MEMLIMIT_ERROR:
+                msg = "Memory usage limit reached";
+                break;
+
+            case LZMA_FORMAT_ERROR:
+                msg = "File format not recognized";
+                break;
+
+            case LZMA_OPTIONS_ERROR:
+                // FIXME: Better message?
+                msg = "Unsupported compression options";
+                break;
+
+            case LZMA_DATA_ERROR:
+                msg = "File is corrupt";
+                break;
+
+            case LZMA_BUF_ERROR:
+                msg = "Unexpected end of input";
+                break;
+
+            default:
+                msg = "Internal program error (bug)";
+                break;
+            }
+            xc_dom_printf("%s: LZMA decompression error %s\n",
+                          __FUNCTION__, msg);
+            break;
+        }
+    }
+
+    xc_dom_printf("%s: LZMA decompress OK, 0x%zx -> 0x%zx\n",
+                  __FUNCTION__, *size, (size_t)stream.total_out);
+
+    *blob = out_buf;
+    *size = stream.total_out;
+
+ lzma_cleanup:
+    lzma_end(&stream);
+
+    return retval;
+}
+
+#else /* !defined(HAVE_LZMA) */
+
+static int xc_try_lzma_decode(
+    struct xc_dom_image *dom, void **blob, size_t *size)
+{
+    xc_dom_printf("%s: LZMA decompress support unavailable\n",
+                  __FUNCTION__);
+    return -1;
+}
+
+#endif
+
 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;
+    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));
 
 extern struct xc_dom_loader elf_loader;
@@ -70,22 +317,22 @@ static unsigned int payload_offset(struct setup_header *hdr)
     return off;
 }
 
-static int check_bzimage_kernel(struct xc_dom_image *dom, int verbose)
+static int xc_dom_probe_bzimage_kernel(struct xc_dom_image *dom)
 {
     struct setup_header *hdr;
+    int ret;
 
     if ( dom->kernel_blob == NULL )
     {
-        if ( verbose )
-            xc_dom_panic(XC_INTERNAL_ERROR, "%s: no kernel image loaded\n",
-                         __FUNCTION__);
+        xc_dom_panic(XC_INTERNAL_ERROR, "%s: no kernel image loaded\n",
+                     __FUNCTION__);
         return -EINVAL;
     }
+
     if ( dom->kernel_size < sizeof(struct setup_header) )
     {
-        if ( verbose )
-            xc_dom_panic(XC_INTERNAL_ERROR, "%s: kernel image too small\n",
-                         __FUNCTION__);
+        xc_dom_panic(XC_INTERNAL_ERROR, "%s: kernel image too small\n",
+                     __FUNCTION__);
         return -EINVAL;
     }
 
@@ -93,39 +340,64 @@ static int check_bzimage_kernel(struct xc_dom_image *dom, int verbose)
 
     if ( memcmp(&hdr->header, HDR_MAGIC, HDR_MAGIC_SZ) != 0 )
     {
-        if ( verbose )
-            xc_dom_panic(XC_INVALID_KERNEL, "%s: kernel is not a bzImage\n",
-                         __FUNCTION__);
+        xc_dom_panic(XC_INVALID_KERNEL, "%s: kernel is not a bzImage\n",
+                     __FUNCTION__);
         return -EINVAL;
     }
 
     if ( hdr->version < VERSION(2,8) )
     {
-        if ( verbose )
-            xc_dom_panic(XC_INVALID_KERNEL, "%s: boot protocol too old (%04x)\n",
-                         __FUNCTION__, hdr->version);
+        xc_dom_panic(XC_INVALID_KERNEL, "%s: boot protocol too old (%04x)\n",
+                     __FUNCTION__, hdr->version);
         return -EINVAL;
     }
 
     dom->kernel_blob = dom->kernel_blob + payload_offset(hdr);
     dom->kernel_size = hdr->payload_length;
 
-    if ( xc_dom_try_gunzip(dom, &dom->kernel_blob, &dom->kernel_size) == -1 )
+    if ( memcmp(dom->kernel_blob, "\037\213", 2) == 0 )
     {
-        if ( verbose )
-            xc_dom_panic(XC_INVALID_KERNEL, "%s: unable to decompress kernel\n",
+        ret = xc_dom_try_gunzip(dom, &dom->kernel_blob, &dom->kernel_size);
+        if ( ret == -1 )
+        {
+            xc_dom_panic(XC_INVALID_KERNEL,
+                         "%s: unable to gzip decompress kernel\n",
                          __FUNCTION__);
+            return -EINVAL;
+        }
+    }
+    else if ( memcmp(dom->kernel_blob, "\102\132\150", 3) == 0 )
+    {
+        ret = xc_try_bzip2_decode(dom, &dom->kernel_blob, &dom->kernel_size);
+        if ( ret < 0 )
+        {
+            xc_dom_panic(XC_INVALID_KERNEL,
+                         "%s unable to BZIP2 decompress kernel",
+                         __FUNCTION__);
+            return -EINVAL;
+        }
+    }
+    else if ( memcmp(dom->kernel_blob, "\135\000", 2) == 0 )
+    {
+        ret = xc_try_lzma_decode(dom, &dom->kernel_blob, &dom->kernel_size);
+        if ( ret < 0 )
+        {
+            xc_dom_panic(XC_INVALID_KERNEL,
+                         "%s unable to LZMA decompress kernel\n",
+                         __FUNCTION__);
+            return -EINVAL;
+        }
+    }
+    else
+    {
+        xc_dom_panic(XC_INVALID_KERNEL, "%s: unknown compression format\n",
+                     __FUNCTION__);
         return -EINVAL;
     }
 
     return elf_loader.probe(dom);
 }
 
-static int xc_dom_probe_bzimage_kernel(struct xc_dom_image *dom)
-{
-    return check_bzimage_kernel(dom, 0);
-}
-
 static int xc_dom_parse_bzimage_kernel(struct xc_dom_image *dom)
 {
     return elf_loader.parser(dom);