From ec3b6f34ab30ee0609ff7b6fd37d856f105866fd Mon Sep 17 00:00:00 2001

Message-Id: <ec3b6f34ab30ee0609ff7b6fd37d856f105866fd.1391615407.git.jdenemar@redhat.com>

From: John Ferlan <jferlan@redhat.com>

Date: Tue, 4 Feb 2014 13:34:52 -0500

Subject: [PATCH] utils: Introduce functions for kernel module manipulation

https://bugzilla.redhat.com/show_bug.cgi?id=1045124

virKModConfig()        - Return a buffer containing kernel module configuration

virKModLoad()          - Load a specific module into the kernel configuration

virKModUnload()        - Unload a specific module from the kernel configuration

virKModIsBlacklisted() - Determine whether a module is blacklisted within

                         the kernel configuration

(cherry picked from commit 4a2179ea9224ec01c036de116c0c226ce3f4d436)

Signed-off-by: John Ferlan <jferlan@redhat.com>

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>

---

 configure.ac             |   6 ++

 src/Makefile.am          |   1 +

 src/libvirt_private.syms |   7 ++

 src/util/virkmod.c       | 181 +++++++++++++++++++++++++++++++++++++++++++++++

 src/util/virkmod.h       |  34 +++++++++

 5 files changed, 229 insertions(+)

 create mode 100644 src/util/virkmod.c

 create mode 100644 src/util/virkmod.h

diff --git a/configure.ac b/configure.ac

index eb20f1c..1fe901d 100644

--- a/configure.ac

+++ b/configure.ac

@@ -327,6 +327,8 @@ AC_PATH_PROG([UDEVSETTLE], [udevsettle], [],

 	[/sbin:/usr/sbin:/usr/local/sbin:$PATH])

 AC_PATH_PROG([MODPROBE], [modprobe], [modprobe],

 	[/sbin:/usr/sbin:/usr/local/sbin:$PATH])

+AC_PATH_PROG([RMMOD], [rmmod], [rmmod],

+	[/sbin:/usr/sbin:/usr/local/sbin:$PATH])

 AC_PATH_PROG([OVSVSCTL], [ovs-vsctl], [ovs-vsctl],

 	[/sbin:/usr/sbin:/usr/local/sbin:$PATH])

 AC_PATH_PROG([SCRUB], [scrub], [scrub],

@@ -353,6 +355,10 @@ if test -n "$MODPROBE"; then

   AC_DEFINE_UNQUOTED([MODPROBE],["$MODPROBE"],

         [Location or name of the modprobe program])

 fi

+if test -n "$RMMOD"; then

+  AC_DEFINE_UNQUOTED([RMMOD],["$RMMOD"],

+        [Location or name of the rmmod program])

+fi

 AC_DEFINE_UNQUOTED([SCRUB],["$SCRUB"],

         [Location or name of the scrub program (for wiping algorithms)])

diff --git a/src/Makefile.am b/src/Makefile.am

index 2dddf15..8a7cefb 100644

--- a/src/Makefile.am

+++ b/src/Makefile.am

@@ -122,6 +122,7 @@ UTIL_SOURCES =							\

 		util/virnetdevvportprofile.h util/virnetdevvportprofile.c \

 		util/virnetlink.c util/virnetlink.h		\

 		util/virnodesuspend.c util/virnodesuspend.h	\

+		util/virkmod.c util/virkmod.h                   \

 		util/virnuma.c util/virnuma.h			\

 		util/virobject.c util/virobject.h		\

 		util/virpci.c util/virpci.h			\

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms

index a07b52e..a1b3e4a 100644

--- a/src/libvirt_private.syms

+++ b/src/libvirt_private.syms

@@ -1547,6 +1547,13 @@ virKeyFileLoadFile;

 virKeyFileNew;

+# util/virkmod.h

+virKModConfig;

+virKModIsBlacklisted;

+virKModLoad;

+virKModUnload;

+

+

 # util/virlockspace.h

 virLockSpaceAcquireResource;

 virLockSpaceCreateResource;

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

new file mode 100644

index 0000000..73cb3c7

--- /dev/null

+++ b/src/util/virkmod.c

@@ -0,0 +1,181 @@

+/*

+ * virkmod.c: helper APIs for managing kernel modules

+ *

+ * Copyright (C) 2014 Red Hat, Inc.

+ *

+ * This library is free software; you can redistribute it and/or

+ * modify it under the terms of the GNU Lesser General Public

+ * License as published by the Free Software Foundation; either

+ * version 2.1 of the License, or (at your option) any later version.

+ *

+ * This library is distributed in the hope that it will be useful,

+ * but WITHOUT ANY WARRANTY; without even the implied warranty of

+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

+ * Lesser General Public License for more details.

+ *

+ * You should have received a copy of the GNU Lesser General Public

+ * License along with this library.  If not, see

+ * <http://www.gnu.org/licenses/>.

+ *

+ */

+

+#include <config.h>

+#include "viralloc.h"

+#include "virkmod.h"

+#include "vircommand.h"

+#include "virstring.h"

+

+static int

+doModprobe(const char *opts, const char *module, char **outbuf, char **errbuf)

+{

+    int ret = -1;

+    virCommandPtr cmd = NULL;

+

+    cmd = virCommandNew(MODPROBE);

+    if (opts)

+        virCommandAddArg(cmd, opts);

+    if (module)

+        virCommandAddArg(cmd, module);

+    if (outbuf)

+        virCommandSetOutputBuffer(cmd, outbuf);

+    if (errbuf)

+        virCommandSetErrorBuffer(cmd, errbuf);

+

+    if (virCommandRun(cmd, NULL) < 0)

+        goto cleanup;

+

+    ret = 0;

+

+cleanup:

+    virCommandFree(cmd);

+    return ret;

+}

+

+static int

+doRmmod(const char *module, char **errbuf)

+{

+    int ret = -1;

+    virCommandPtr cmd = NULL;

+

+    cmd = virCommandNewArgList(RMMOD, module, NULL);

+    virCommandSetErrorBuffer(cmd, errbuf);

+

+    if (virCommandRun(cmd, NULL) < 0)

+        goto cleanup;

+

+    ret = 0;

+

+cleanup:

+    virCommandFree(cmd);

+    return ret;

+}

+

+/**

+ * virKModConfig:

+ *

+ * Get the current kernel module configuration

+ *

+ * Returns NULL on failure or a pointer to the output which

+ * must be VIR_FREE()'d by the caller

+ */

+char *

+virKModConfig(void)

+{

+    char *outbuf = NULL;

+

+    if (doModprobe("-c", NULL, &outbuf, NULL) < 0)

+        return NULL;

+

+    return outbuf;

+}

+

+

+/**

+ * virKModLoad:

+ * @module: Name of the module to load

+ * @useBlacklist: True if honoring blacklist

+ *

+ * Attempts to load a kernel module

+ *

+ * returns NULL in case of success and the error buffer output from the

+ * virCommandRun() on failure.  The returned buffer must be VIR_FREE()

+ * by the caller

+ */

+char *

+virKModLoad(const char *module, bool useBlacklist)

+{

+    char *errbuf = NULL;

+

+    if (doModprobe(useBlacklist ? "-b" : NULL, module, NULL, &errbuf) < 0)

+        return errbuf;

+

+    VIR_FREE(errbuf);

+    return NULL;

+}

+

+

+/**

+ * virKModUnload:

+ * @module: Name of the module to unload

+ *

+ * Remove or unload a module.

+ *

+ * NB: Do not use 'modprobe -r' here as that code will recursively

+ * unload any modules that were dependancies of the one being removed

+ * even if things still require them. e.g. it'll see the 'bridge'

+ * module has refcount of 0 and remove it, even if there are bridges

+ * created on the host

+ *

+ * returns NULL in case of success and the error buffer output from the

+ * virCommandRun() on failure.  The returned buffer must be VIR_FREE()

+ * by the caller

+ */

+char *

+virKModUnload(const char *module)

+{

+    char *errbuf = NULL;

+

+    if (doRmmod(module, &errbuf) < 0)

+        return errbuf;

+

+    VIR_FREE(errbuf);

+    return NULL;

+}

+

+

+/**

+ * virKModIsBlacklisted:

+ * @module: Name of the module to check for on the blacklist

+ *

+ * Search the output of the configuration data for the module being

+ * blacklisted.

+ *

+ * returns true when found blacklisted, false otherwise.

+ */

+bool

+virKModIsBlacklisted(const char *module)

+{

+    bool retval = false;

+    size_t i;

+    char *drvblklst = NULL;

+    char *outbuf = NULL;

+

+    if (virAsprintfQuiet(&drvblklst, "blacklist %s\n", module) < 0)

+        goto cleanup;

+

+    /* modprobe will convert all '-' into '_', so we need to as well */

+    for (i = 0; i < drvblklst[i]; i++)

+        if (drvblklst[i] == '-')

+            drvblklst[i] = '_';

+

+    if (doModprobe("-c", NULL, &outbuf, NULL) < 0)

+        goto cleanup;

+

+    if (strstr(outbuf, drvblklst))

+        retval = true;

+

+cleanup:

+    VIR_FREE(drvblklst);

+    VIR_FREE(outbuf);

+    return retval;

+}

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

new file mode 100644

index 0000000..608f1b8

--- /dev/null

+++ b/src/util/virkmod.h

@@ -0,0 +1,34 @@

+/*

+ * virkmod.h: helper APIs for managing kernel modprobe

+ *

+ * Copyright (C) 2014 Red Hat, Inc.

+ *

+ * This library is free software; you can redistribute it and/or

+ * modify it under the terms of the GNU Lesser General Public

+ * License as published by the Free Software Foundation; either

+ * version 2.1 of the License, or (at your option) any later version.

+ *

+ * This library is distributed in the hope that it will be useful,

+ * but WITHOUT ANY WARRANTY; without even the implied warranty of

+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

+ * Lesser General Public License for more details.

+ *

+ * You should have received a copy of the GNU Lesser General Public

+ * License along with this library.  If not, see

+ * <http://www.gnu.org/licenses/>.

+ *

+ */

+

+#ifndef __VIR_KMOD_H__

+# define __VIR_KMOD_H__

+

+# include "internal.h"

+

+char *virKModConfig(void);

+char *virKModLoad(const char *, bool)

+    ATTRIBUTE_NONNULL(1);

+char *virKModUnload(const char *)

+    ATTRIBUTE_NONNULL(1);

+bool virKModIsBlacklisted(const char *)

+    ATTRIBUTE_NONNULL(1);

+#endif /* __VIR_KMOD_H__ */

-- 

1.8.5.3