[PATCH 15/28] kvm tools: Allow initrd_check() to match a cpio

Matt Evans
2011-12-06T03:40:55Z

cpios are valid as initrds too, so allow them through the check.

Signed-off-by: Matt Evans <matt@ozlabs.org>
---
tools/kvm/kvm.c | 8 +++++---
1 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/tools/kvm/kvm.c b/tools/kvm/kvm.c
index 33243f1..457de1a 100644
--- a/tools/kvm/kvm.c
+++ b/tools/kvm/kvm.c
@@ -317,10 +317,11 @@ struct kvm *kvm__init(const char *kvm_dev, u64 ram_size, const char *name)
/* RFC 1952 */
#define GZIP_ID1 0x1f
#define GZIP_ID2 0x8b
-
+#define CPIO_MAGIC "0707"
+/* initrd may be gzipped, or a plain cpio */
static bool initrd_check(int fd)
{
- unsigned char id[2];
+ unsigned char id[4];

if (read_in_full(fd, id, ARRAY_SIZE(id)) < 0)
return false;
@@ -328,7 +329,8 @@ static bool initrd_check(int fd)
if (lseek(fd, 0, SEEK_SET) < 0)
die_perror("lseek");

- return id[0] = GZIP_ID1 && id[1] = GZIP_ID2;
+ return (id[0] = GZIP_ID1 && id[1] = GZIP_ID2) ||
+ !memcmp(id, CPIO_MAGIC, 4);
}

bool kvm__load_kernel(struct kvm *kvm, const char *kernel_filename,