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[PATCH v2 1/1] modules: load modules from versioned /var/run dir
From: |
Christian Ehrhardt |
Subject: |
[PATCH v2 1/1] modules: load modules from versioned /var/run dir |
Date: |
Tue, 10 Mar 2020 15:58:06 +0100 |
On upgrades the old .so files usually are replaced. But on the other
hand since a qemu process represents a guest instance it is usually kept
around.
That makes late addition of dynamic features e.g. 'hot-attach of a ceph
disk' fail by trying to load a new version of e.f. block-rbd.so into an
old still running qemu binary.
This adds a fallback to also load modules from a versioned directory in the
temporary /var/run path. That way qemu is providing a way for packaging
to store modules of an upgraded qemu package as needed until the next reboot.
An example how that can then be used in packaging can be seen in:
https://git.launchpad.net/~paelzer/ubuntu/+source/qemu/log/?h=bug-1847361-miss-old-so-on-upgrade-UBUNTU
Fixes: https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/1847361
Signed-off-by: Christian Ehrhardt <address@hidden>
---
configure | 15 +++++++++++++++
util/module.c | 14 ++++++++++++++
2 files changed, 29 insertions(+)
diff --git a/configure b/configure
index cbf864bff1..5911bf1a82 100755
--- a/configure
+++ b/configure
@@ -405,6 +405,7 @@ EXESUF=""
DSOSUF=".so"
LDFLAGS_SHARED="-shared"
modules="no"
+module_upgrades="no"
prefix="/usr/local"
mandir="\${prefix}/share/man"
datadir="\${prefix}/share"
@@ -1032,6 +1033,10 @@ for opt do
--disable-modules)
modules="no"
;;
+ --disable-module-upgrades) module_upgrades="no"
+ ;;
+ --enable-module-upgrades) module_upgrades="yes"
+ ;;
--cpu=*)
;;
--target-list=*) target_list="$optarg"
@@ -1786,6 +1791,7 @@ disabled with --disable-FEATURE, default is enabled if
available:
guest-agent-msi build guest agent Windows MSI installation package
pie Position Independent Executables
modules modules support (non-Windows)
+ module-upgrades try to load modules from alternate paths for upgrades
debug-tcg TCG debugging (default is disabled)
debug-info debugging information
sparse sparse checker
@@ -2049,6 +2055,11 @@ if test "$modules" = "yes" && test "$mingw32" = "yes" ;
then
error_exit "Modules are not available for Windows"
fi
+# module_upgrades is only reasonable if modules are enabled
+if test "$modules" = "no" && test "$module_upgrades" = "yes" ; then
+ error_exit "Can't enable module-upgrades as Modules are not enabled"
+fi
+
# Static linking is not possible with modules or PIE
if test "$static" = "yes" ; then
if test "$modules" = "yes" ; then
@@ -6584,6 +6595,7 @@ if test "$slirp" != "no" ; then
echo "smbd $smbd"
fi
echo "module support $modules"
+echo "alt path mod load $module_upgrades"
echo "host CPU $cpu"
echo "host big endian $bigendian"
echo "target list $target_list"
@@ -6937,6 +6949,9 @@ if test "$modules" = "yes"; then
echo "CONFIG_STAMP=_$( (echo $qemu_version; echo $pkgversion; cat $0) |
$shacmd - | cut -f1 -d\ )" >> $config_host_mak
echo "CONFIG_MODULES=y" >> $config_host_mak
fi
+if test "$module_upgrades" = "yes"; then
+ echo "CONFIG_MODULE_UPGRADES=y" >> $config_host_mak
+fi
if test "$have_x11" = "yes" && test "$need_x11" = "yes"; then
echo "CONFIG_X11=y" >> $config_host_mak
echo "X11_CFLAGS=$x11_cflags" >> $config_host_mak
diff --git a/util/module.c b/util/module.c
index 236a7bb52a..5f7896870a 100644
--- a/util/module.c
+++ b/util/module.c
@@ -19,6 +19,9 @@
#endif
#include "qemu/queue.h"
#include "qemu/module.h"
+#ifdef CONFIG_MODULE_UPGRADES
+#include "qemu-version.h"
+#endif
typedef struct ModuleEntry
{
@@ -170,6 +173,9 @@ bool module_load_one(const char *prefix, const char
*lib_name)
#ifdef CONFIG_MODULES
char *fname = NULL;
char *exec_dir;
+#ifdef CONFIG_MODULE_UPGRADES
+ char *version_dir;
+#endif
const char *search_dir;
char *dirs[4];
char *module_name;
@@ -201,6 +207,14 @@ bool module_load_one(const char *prefix, const char
*lib_name)
dirs[n_dirs++] = g_strdup_printf("%s", CONFIG_QEMU_MODDIR);
dirs[n_dirs++] = g_strdup_printf("%s/..", exec_dir ? : "");
dirs[n_dirs++] = g_strdup_printf("%s", exec_dir ? : "");
+
+#ifdef CONFIG_MODULE_UPGRADES
+ version_dir = g_strcanon(g_strdup(QEMU_PKGVERSION),
+ G_CSET_A_2_Z G_CSET_a_2_z G_CSET_DIGITS "+-.~",
+ '_');
+ dirs[n_dirs++] = g_strdup_printf("/var/run/qemu/%s", version_dir);
+#endif
+
assert(n_dirs <= ARRAY_SIZE(dirs));
g_free(exec_dir);
--
2.25.1