From 726a63a437efd96510ce316bf30d16f213d4db27 Mon Sep 17 00:00:00 2001

From: Daniel P. Berrange <berrange@redhat.com>

Date: Tue, 15 Jun 2010 16:15:51 +0100

Subject: [PATCH 04/11] Require format to be passed into virStorageFileGetMetadata

Require the disk image to be passed into virStorageFileGetMetadata.

If this is set to VIR_STORAGE_FILE_AUTO, then the format will be

resolved using probing. This makes it easier to control when

probing will be used

* src/qemu/qemu_driver.c, src/qemu/qemu_security_dac.c,

  src/security/security_selinux.c, src/security/virt-aa-helper.c:

  Set VIR_STORAGE_FILE_AUTO when calling virStorageFileGetMetadata.

* src/storage/storage_backend_fs.c: Probe for disk format before

  calling virStorageFileGetMetadata.

* src/util/storage_file.h, src/util/storage_file.c: Remove format

  from virStorageFileMeta struct & require it to be passed into

  method.

---

 src/qemu/qemu_driver.c           |   27 +++++++++++++++++---

 src/qemu/qemu_security_dac.c     |    4 ++-

 src/security/security_selinux.c  |    4 ++-

 src/security/virt-aa-helper.c    |    4 ++-

 src/storage/storage_backend_fs.c |   11 ++++++--

 src/util/storage_file.c          |   50 +++++++++++++++++++++++++------------

 src/util/storage_file.h          |    3 +-

 7 files changed, 76 insertions(+), 27 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c

index 487bfa3..97f2990 100644

--- a/src/qemu/qemu_driver.c

+++ b/src/qemu/qemu_driver.c

@@ -3069,7 +3069,9 @@ static int qemuSetupDiskCgroup(virCgroupPtr cgroup,

             }

         }

-        rc = virStorageFileGetMetadata(path, &meta);

+        rc = virStorageFileGetMetadata(path,

+                                       VIR_STORAGE_FILE_AUTO,

+                                       &meta);

         if (rc < 0)

             VIR_WARN("Unable to lookup parent image for %s", path);

@@ -3119,7 +3121,9 @@ static int qemuTeardownDiskCgroup(virCgroupPtr cgroup,

             }

         }

-        rc = virStorageFileGetMetadata(path, &meta);

+        rc = virStorageFileGetMetadata(path,

+                                       VIR_STORAGE_FILE_AUTO,

+                                       &meta);

         if (rc < 0)

             VIR_WARN("Unable to lookup parent image for %s", path);

@@ -9614,6 +9618,7 @@ static int qemuDomainGetBlockInfo(virDomainPtr dom,

     virDomainDiskDefPtr disk = NULL;

     struct stat sb;

     int i;

+    int format;

     virCheckFlags(0, -1);

@@ -9658,7 +9663,21 @@ static int qemuDomainGetBlockInfo(virDomainPtr dom,

     }

     /* Probe for magic formats */

-    if (virStorageFileGetMetadataFromFD(path, fd, &meta) < 0)

+    if (disk->driverType) {

+        if ((format = virStorageFileFormatTypeFromString(disk->driverType)) < 0) {

+            qemuReportError(VIR_ERR_INTERNAL_ERROR,

+                            _("unknown disk format %s for %s"),

+                            disk->driverType, disk->src);

+            goto cleanup;

+        }

+    } else {

+        if ((format = virStorageFileProbeFormat(disk->src)) < 0)

+            goto cleanup;

+    }

+

+    if (virStorageFileGetMetadataFromFD(path, fd,

+                                        format,

+                                        &meta) < 0)

         goto cleanup;

     /* Get info for normal formats */

@@ -9706,7 +9725,7 @@ static int qemuDomainGetBlockInfo(virDomainPtr dom,

        highest allocated extent from QEMU */

     if (virDomainObjIsActive(vm) &&

         disk->type == VIR_DOMAIN_DISK_TYPE_BLOCK &&

-        meta.format != VIR_STORAGE_FILE_RAW &&

+        format != VIR_STORAGE_FILE_RAW &&

         S_ISBLK(sb.st_mode)) {

         qemuDomainObjPrivatePtr priv = vm->privateData;

         if (qemuDomainObjBeginJob(vm) < 0)

diff --git a/src/qemu/qemu_security_dac.c b/src/qemu/qemu_security_dac.c

index 95015b0..acfe48e 100644

--- a/src/qemu/qemu_security_dac.c

+++ b/src/qemu/qemu_security_dac.c

@@ -115,7 +115,9 @@ qemuSecurityDACSetSecurityImageLabel(virDomainObjPtr vm ATTRIBUTE_UNUSED,

         virStorageFileMetadata meta;

         int ret;

-        ret = virStorageFileGetMetadata(path, &meta);

+        ret = virStorageFileGetMetadata(path,

+                                        VIR_STORAGE_FILE_AUTO,

+                                        &meta);

         if (path != disk->src)

             VIR_FREE(path);

diff --git a/src/security/security_selinux.c b/src/security/security_selinux.c

index e5eef19..5c0f002 100644

--- a/src/security/security_selinux.c

+++ b/src/security/security_selinux.c

@@ -457,7 +457,9 @@ SELinuxSetSecurityImageLabel(virDomainObjPtr vm,

         virStorageFileMetadata meta;

         int ret;

-        ret = virStorageFileGetMetadata(path, &meta);

+        ret = virStorageFileGetMetadata(path,

+                                        VIR_STORAGE_FILE_AUTO,

+                                        &meta);

         if (path != disk->src)

             VIR_FREE(path);

diff --git a/src/security/virt-aa-helper.c b/src/security/virt-aa-helper.c

index c66f107..2c045e6 100644

--- a/src/security/virt-aa-helper.c

+++ b/src/security/virt-aa-helper.c

@@ -830,7 +830,9 @@ get_files(vahControl * ctl)

             do {

                 virStorageFileMetadata meta;

-                ret = virStorageFileGetMetadata(path, &meta);

+                ret = virStorageFileGetMetadata(path,

+                                                VIR_STORAGE_FILE_AUTO,

+                                                &meta);

                 if (path != ctl->def->disks[i]->src)

                     VIR_FREE(path);

diff --git a/src/storage/storage_backend_fs.c b/src/storage/storage_backend_fs.c

index f0cd770..d3ac0fe 100644

--- a/src/storage/storage_backend_fs.c

+++ b/src/storage/storage_backend_fs.c

@@ -75,14 +75,19 @@ virStorageBackendProbeTarget(virStorageVolTargetPtr target,

     memset(&meta, 0, sizeof(meta));

-    if (virStorageFileGetMetadataFromFD(target->path, fd, &meta) < 0) {

+    if ((target->format = virStorageFileProbeFormatFromFD(target->path, fd)) < 0) {

         close(fd);

         return -1;

     }

-    close(fd);

+    if (virStorageFileGetMetadataFromFD(target->path, fd,

+                                        target->format,

+                                        &meta) < 0) {

+        close(fd);

+        return -1;

+    }

-    target->format = meta.format;

+    close(fd);

     if (backingStore) {

         *backingStore = meta.backingStore;

diff --git a/src/util/storage_file.c b/src/util/storage_file.c

index 221268b..9712d92 100644

--- a/src/util/storage_file.c

+++ b/src/util/storage_file.c

@@ -696,18 +696,23 @@ virStorageFileProbeFormat(const char *path)

 /**

  * virStorageFileGetMetadataFromFD:

  *

- * Probe for the format of 'fd' (which is an open file descriptor

- * for the file 'path'), filling 'meta' with the detected

- * format and other associated metadata.

+ * Extract metadata about the storage volume with the specified

+ * image format. If image format is VIR_STORAGE_FILE_AUTO, it

+ * will probe to automatically identify the format. 

  *

- * Callers are advised never to trust the returned 'meta->format'

- * unless it is listed as VIR_STORAGE_FILE_RAW, since a

- * malicious guest can turn a raw file into any other non-raw

- * format at will.

+ * Callers are advised never to use VIR_STORAGE_FILE_AUTO as a

+ * format, since a malicious guest can turn a raw file into any

+ * other non-raw format at will.

+ *

+ * If the returned meta.backingStoreFormat is VIR_STORAGE_FILE_AUTO

+ * it indicates the image didn't specify an explicit format for its

+ * backing store. Callers are advised against probing for the

+ * backing store format in this case.

  */

 int

 virStorageFileGetMetadataFromFD(const char *path,

                                 int fd,

+                                int format,

                                 virStorageFileMetadata *meta)

 {

     unsigned char *head;

@@ -731,9 +736,16 @@ virStorageFileGetMetadataFromFD(const char *path,

         goto cleanup;

     }

-    meta->format = virStorageFileProbeFormatFromBuf(path, head, len);

+    if (format == VIR_STORAGE_FILE_AUTO)

+        format = virStorageFileProbeFormatFromBuf(path, head, len);

+

+    if (format < 0 ||

+        format >= VIR_STORAGE_FILE_LAST) {

+        virReportSystemError(EINVAL, _("unknown storage file format %d"), format);

+        return -1;

+    }

-    ret = virStorageFileGetMetadataFromBuf(meta->format, path, head, len, meta);

+    ret = virStorageFileGetMetadataFromBuf(format, path, head, len, meta);

 cleanup:

     VIR_FREE(head);

@@ -743,16 +755,22 @@ cleanup:

 /**

  * virStorageFileGetMetadata:

  *

- * Probe for the format of 'path', filling 'meta' with the detected

- * format and other associated metadata.

+ * Extract metadata about the storage volume with the specified

+ * image format. If image format is VIR_STORAGE_FILE_AUTO, it

+ * will probe to automatically identify the format. 

  *

- * Callers are advised never to trust the returned 'meta->format'

- * unless it is listed as VIR_STORAGE_FILE_RAW, since a

- * malicious guest can turn a raw file into any other non-raw

- * format at will.

+ * Callers are advised never to use VIR_STORAGE_FILE_AUTO as a

+ * format, since a malicious guest can turn a raw file into any

+ * other non-raw format at will.

+ *

+ * If the returned meta.backingStoreFormat is VIR_STORAGE_FILE_AUTO

+ * it indicates the image didn't specify an explicit format for its

+ * backing store. Callers are advised against probing for the

+ * backing store format in this case.

  */

 int

 virStorageFileGetMetadata(const char *path,

+                          int format,

                           virStorageFileMetadata *meta)

 {

     int fd, ret;

@@ -762,7 +780,7 @@ virStorageFileGetMetadata(const char *path,

         return -1;

     }

-    ret = virStorageFileGetMetadataFromFD(path, fd, meta);

+    ret = virStorageFileGetMetadataFromFD(path, fd, format, meta);

     close(fd);

diff --git a/src/util/storage_file.h b/src/util/storage_file.h

index 3420d44..6853182 100644

--- a/src/util/storage_file.h

+++ b/src/util/storage_file.h

@@ -46,7 +46,6 @@ enum virStorageFileFormat {

 VIR_ENUM_DECL(virStorageFileFormat);

 typedef struct _virStorageFileMetadata {

-    int format;

     char *backingStore;

     int backingStoreFormat;

     unsigned long long capacity;

@@ -62,9 +61,11 @@ int virStorageFileProbeFormatFromFD(const char *path,

                                     int fd);

 int virStorageFileGetMetadata(const char *path,

+                              int format,

                               virStorageFileMetadata *meta);

 int virStorageFileGetMetadataFromFD(const char *path,

                                     int fd,

+                                    int format,

                                     virStorageFileMetadata *meta);

 int virStorageFileIsSharedFS(const char *path);

-- 

1.7.1.1