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[Qemu-devel] [PATCH] block: add read only to whitelist
From: |
Fam Zheng |
Subject: |
[Qemu-devel] [PATCH] block: add read only to whitelist |
Date: |
Tue, 28 May 2013 14:44:26 +0800 |
We may want to include a driver in the whitelist for read only tasks
such as diagnosing or exporting guest data (with libguestfs as a good
example). This patch introduces the magic prefix ^ to include a driver
to the whitelist, but only enables qemu to open specific image
format readonly, and returns -ENOTSUP for RW opening.
Example: To include vmdk readonly, and others read+write:
./configure --block-drv-whitelist=qcow2,raw,file,qed,^vmdk
Signed-off-by: Fam Zheng <address@hidden>
---
block.c | 43 +++++++++++++++++++++++++++----------------
blockdev.c | 4 ++--
configure | 2 ++
include/block/block.h | 3 ++-
scripts/create_config | 9 ++++++++-
5 files changed, 41 insertions(+), 20 deletions(-)
diff --git a/block.c b/block.c
index 3f87489..e6a7270 100644
--- a/block.c
+++ b/block.c
@@ -328,28 +328,40 @@ BlockDriver *bdrv_find_format(const char *format_name)
return NULL;
}
-static int bdrv_is_whitelisted(BlockDriver *drv)
+static int bdrv_is_whitelisted(BlockDriver *drv, bool read_only)
{
- static const char *whitelist[] = {
- CONFIG_BDRV_WHITELIST
+ static const char *whitelist_rw[] = {
+ CONFIG_BDRV_WHITELIST_RW
+ };
+ static const char *whitelist_ro[] = {
+ CONFIG_BDRV_WHITELIST_RO
};
const char **p;
- if (!whitelist[0])
+ if (!whitelist_rw[0] && !whitelist_ro[0]) {
return 1; /* no whitelist, anything goes */
+ }
- for (p = whitelist; *p; p++) {
+ for (p = whitelist_rw; *p; p++) {
if (!strcmp(drv->format_name, *p)) {
return 1;
}
}
+ if (read_only) {
+ for (p = whitelist_ro; *p; p++) {
+ if (!strcmp(drv->format_name, *p)) {
+ return 1;
+ }
+ }
+ }
return 0;
}
-BlockDriver *bdrv_find_whitelisted_format(const char *format_name)
+BlockDriver *bdrv_find_whitelisted_format(const char *format_name,
+ bool read_only)
{
BlockDriver *drv = bdrv_find_format(format_name);
- return drv && bdrv_is_whitelisted(drv) ? drv : NULL;
+ return drv && bdrv_is_whitelisted(drv, read_only) ? drv : NULL;
}
typedef struct CreateCo {
@@ -684,10 +696,6 @@ static int bdrv_open_common(BlockDriverState *bs,
BlockDriverState *file,
trace_bdrv_open_common(bs, filename ?: "", flags, drv->format_name);
- if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv)) {
- return -ENOTSUP;
- }
-
/* bdrv_open() with directly using a protocol as drv. This layer is already
* opened, so assign it to bs (while file becomes a closed
BlockDriverState)
* and return immediately. */
@@ -698,9 +706,15 @@ static int bdrv_open_common(BlockDriverState *bs,
BlockDriverState *file,
bs->open_flags = flags;
bs->buffer_alignment = 512;
+ open_flags = bdrv_open_flags(bs, flags);
+ bs->read_only = !(open_flags & BDRV_O_RDWR);
+
+ if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) {
+ return -ENOTSUP;
+ }
assert(bs->copy_on_read == 0); /* bdrv_new() and bdrv_close() make it so */
- if ((flags & BDRV_O_RDWR) && (flags & BDRV_O_COPY_ON_READ)) {
+ if (!bs->read_only && (flags & BDRV_O_COPY_ON_READ)) {
bdrv_enable_copy_on_read(bs);
}
@@ -714,9 +728,6 @@ static int bdrv_open_common(BlockDriverState *bs,
BlockDriverState *file,
bs->opaque = g_malloc0(drv->instance_size);
bs->enable_write_cache = !!(flags & BDRV_O_CACHE_WB);
- open_flags = bdrv_open_flags(bs, flags);
-
- bs->read_only = !(open_flags & BDRV_O_RDWR);
/* Open the image, either directly or using a protocol */
if (drv->bdrv_file_open) {
@@ -801,7 +812,7 @@ int bdrv_file_open(BlockDriverState **pbs, const char
*filename,
/* Find the right block driver */
drvname = qdict_get_try_str(options, "driver");
if (drvname) {
- drv = bdrv_find_whitelisted_format(drvname);
+ drv = bdrv_find_whitelisted_format(drvname, !(flags & BDRV_O_RDWR));
qdict_del(options, "driver");
} else if (filename) {
drv = bdrv_find_protocol(filename);
diff --git a/blockdev.c b/blockdev.c
index d1ec99a..b9b2d10 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -477,7 +477,7 @@ DriveInfo *drive_init(QemuOpts *all_opts,
BlockInterfaceType block_default_type)
error_printf("\n");
return NULL;
}
- drv = bdrv_find_whitelisted_format(buf);
+ drv = bdrv_find_whitelisted_format(buf, ro);
if (!drv) {
error_report("'%s' invalid format", buf);
return NULL;
@@ -1096,7 +1096,7 @@ void qmp_change_blockdev(const char *device, const char
*filename,
}
if (format) {
- drv = bdrv_find_whitelisted_format(format);
+ drv = bdrv_find_whitelisted_format(format, bs->read_only);
if (!drv) {
error_set(errp, QERR_INVALID_BLOCK_FORMAT, format);
return;
diff --git a/configure b/configure
index eb74510..87bf54c 100755
--- a/configure
+++ b/configure
@@ -1106,6 +1106,8 @@ echo " --enable-cocoa enable Cocoa (default on
Mac OS X)"
echo " --audio-drv-list=LIST set audio drivers list:"
echo " Available drivers: $audio_possible_drivers"
echo " --block-drv-whitelist=L set block driver whitelist"
+echo " prefix with ^ to include driver readonly"
+echo " e.g. --block-drv-whitelist=raw,file,^vmdk"
echo " (affects only QEMU, not qemu-img)"
echo " --enable-mixemu enable mixer emulation"
echo " --disable-xen disable xen backend driver support"
diff --git a/include/block/block.h b/include/block/block.h
index 1251c5c..5604418 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -124,7 +124,8 @@ void bdrv_init(void);
void bdrv_init_with_whitelist(void);
BlockDriver *bdrv_find_protocol(const char *filename);
BlockDriver *bdrv_find_format(const char *format_name);
-BlockDriver *bdrv_find_whitelisted_format(const char *format_name);
+BlockDriver *bdrv_find_whitelisted_format(const char *format_name,
+ bool readonly);
int bdrv_create(BlockDriver *drv, const char* filename,
QEMUOptionParameter *options);
int bdrv_create_file(const char* filename, QEMUOptionParameter *options);
diff --git a/scripts/create_config b/scripts/create_config
index c471e8c..2dfda3e 100755
--- a/scripts/create_config
+++ b/scripts/create_config
@@ -35,11 +35,18 @@ case $line in
echo ""
;;
CONFIG_BDRV_WHITELIST=*)
- echo "#define CONFIG_BDRV_WHITELIST \\"
+ echo "#define CONFIG_BDRV_WHITELIST_RW \\"
for drv in ${line#*=}; do
+ [[ "${drv}" = ^* ]] && continue;
echo " \"${drv}\",\\"
done
echo " NULL"
+ echo "#define CONFIG_BDRV_WHITELIST_RO \\"
+ for drv in ${line#*=}; do
+ [[ "${drv}" != ^* ]] && continue;
+ echo " \"${drv#^}\",\\"
+ done
+ echo " NULL"
;;
CONFIG_*=y) # configuration
name=${line%=*}
--
1.8.2.3
- [Qemu-devel] [PATCH] block: add read only to whitelist,
Fam Zheng <=