Re: [PATCH] kvm tool: Make kvm structure to carry name copy

[Cyrill Gorcunov <gorcunov@openvz.org>]

On Sat, Feb 04, 2012 at 02:57:23PM +0200, Pekka Enberg wrote:
> On Sat, 4 Feb 2012, Cyrill Gorcunov wrote:
> >Index: linux-2.6.git/tools/kvm/kvm.c
> >===================================================================
> >--- linux-2.6.git.orig/tools/kvm/kvm.c
> >+++ linux-2.6.git/tools/kvm/kvm.c
> >@@ -254,6 +254,7 @@ int kvm__exit(struct kvm *kvm)
> >	kvm__arch_delete_ram(kvm);
> >	kvm_ipc__stop();
> >	kvm__remove_socket(kvm->name);
> >+	free((void *)kvm->name);
> 
> Please fix the struct definition and drop the cast.
> 

I believe having it as const char * might save us some
potential troubles, but sure, here we go ;)

	Cyrill
---
kvm tool: Make kvm structure to carry name copy

If default guest name is used (which is the default
case) the kvm might end up carrying the pointer to
a name which is allocated on stack.

kvm_cmd_run_init
  (on stack) default_name
  kvm__init(..., default_name)
    kvm->name = default_name

So make it to carry a copy of name.

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
---

 tools/kvm/kvm.c                          |    9 +++++++--
 tools/kvm/powerpc/include/kvm/kvm-arch.h |    2 +-
 tools/kvm/x86/include/kvm/kvm-arch.h     |    2 +-
 3 files changed, 9 insertions(+), 4 deletions(-)

Index: linux-2.6.git/tools/kvm/kvm.c
===================================================================
--- linux-2.6.git.orig/tools/kvm/kvm.c
+++ linux-2.6.git/tools/kvm/kvm.c
@@ -254,6 +254,7 @@ int kvm__exit(struct kvm *kvm)
 	kvm__arch_delete_ram(kvm);
 	kvm_ipc__stop();
 	kvm__remove_socket(kvm->name);
+	free(kvm->name);
 	free(kvm);
 
 	return 0;
@@ -377,6 +378,12 @@ struct kvm *kvm__init(const char *kvm_de
 		goto cleanup;
 	}
 
+	kvm->name = strdup(name);
+	if (!kvm->name) {
+		ret = -ENOMEM;
+		goto cleanup;
+	}
+
 	if (kvm__check_extensions(kvm)) {
 		pr_err("A required KVM extention is not supported by OS");
 		ret = -ENOSYS;
@@ -384,8 +391,6 @@ struct kvm *kvm__init(const char *kvm_de
 
 	kvm__arch_init(kvm, hugetlbfs_path, ram_size);
 
-	kvm->name = name;
-
 	kvm_ipc__start(kvm__create_socket(kvm));
 	kvm_ipc__register_handler(KVM_IPC_PID, kvm__pid);
 	return kvm;
Index: linux-2.6.git/tools/kvm/powerpc/include/kvm/kvm-arch.h
===================================================================
--- linux-2.6.git.orig/tools/kvm/powerpc/include/kvm/kvm-arch.h
+++ linux-2.6.git/tools/kvm/powerpc/include/kvm/kvm-arch.h
@@ -64,7 +64,7 @@ struct kvm {
 	unsigned long		fdt_gra;
 	unsigned long		initrd_gra;
 	unsigned long		initrd_size;
-	const char		*name;
+	char			*name;
 	int			vm_state;
 };
 
Index: linux-2.6.git/tools/kvm/x86/include/kvm/kvm-arch.h
===================================================================
--- linux-2.6.git.orig/tools/kvm/x86/include/kvm/kvm-arch.h
+++ linux-2.6.git/tools/kvm/x86/include/kvm/kvm-arch.h
@@ -48,7 +48,7 @@ struct kvm {
 	struct disk_image       **disks;
 	int                     nr_disks;
 
-	const char		*name;
+	char			*name;
 
 	int			vm_state;
 };