[libvirt] [PATCH 1/2] qemu: blockPeek: Fix filling of the return buffer

[Peter Krempa]

Commit 3956af495e broke the blockPeek API since virStorageFileRead
allocates a return buffer and fills it with the data, while the API
fills a user-provided buffer. This did not get caught by the compiler
since the API prototype uses a 'void *'.

Fix it by transferring the data from the allocated buffer to the user
provided buffer.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1491217
---
 src/qemu/qemu_driver.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index e1a0dd553..93a1c6061 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -11415,6 +11415,7 @@ qemuDomainBlockPeek(virDomainPtr dom,
     virQEMUDriverPtr driver = dom->conn->privateData;
     virDomainDiskDefPtr disk = NULL;
     virDomainObjPtr vm;
+    char *tmpbuf = NULL;
     int ret = -1;

     virCheckFlags(0, -1);
@@ -11444,12 +11445,15 @@ qemuDomainBlockPeek(virDomainPtr dom,
     if (virStorageFileRead(disk->src, offset, size, buffer) < 0)
         goto cleanup;

+    memcpy(buffer, tmpbuf, size);
+
     ret = 0;

  cleanup:
     if (disk)
         virStorageFileDeinit(disk->src);
     virDomainObjEndAPI(&vm);
+    VIR_FREE(tmpbuf);
     return ret;
 }

-- 
2.14.1