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[libvirt] [PATCH v5 04/11] Helper functions for host TPM support



Implement helper functions to find the TPM's sysfs cancel file.

Signed-off-by: Stefan Berger <stefanb linux vnet ibm com>
Reviewed-by: Corey Bryant <coreyb linux vnet ibm com>
Tested-by: Corey Bryant <coreyb linux vnet ibm com>

---
 po/POTFILES.in           |    1 
 src/Makefile.am          |    1 
 src/libvirt_private.syms |    4 +
 src/util/virtpm.c        |  132 +++++++++++++++++++++++++++++++++++++++++++++++
 src/util/virtpm.h        |   27 +++++++++
 5 files changed, 165 insertions(+)

Index: libvirt/src/Makefile.am
===================================================================
--- libvirt.orig/src/Makefile.am
+++ libvirt/src/Makefile.am
@@ -122,6 +122,7 @@ UTIL_SOURCES =							\
 		util/virthreadwin32.h				\
 		util/virthreadpool.c util/virthreadpool.h	\
 		util/virtime.h util/virtime.c			\
+		util/virtpm.h util/virtpm.c			\
 		util/virtypedparam.c util/virtypedparam.h	\
 		util/virusb.c util/virusb.h			\
 		util/viruri.h util/viruri.c			\
Index: libvirt/src/util/virtpm.c
===================================================================
--- /dev/null
+++ libvirt/src/util/virtpm.c
@@ -0,0 +1,132 @@
+/*
+ * virtpm.c: TPM support
+ *
+ * Copyright (C) 2013 IBM Corporation
+ *
+ * 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/>.
+ *
+ * Author: Stefan Berger <stefanb linux vnet ibm com>
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <dirent.h>
+#include <unistd.h>
+#include <sys/stat.h>
+
+#include "c-ctype.h"
+#include "virobject.h"
+#include "viralloc.h"
+#include "virutil.h"
+#include "virerror.h"
+#include "virbuffer.h"
+#include "virtpm.h"
+
+#define VIR_FROM_THIS VIR_FROM_NONE
+
+/*
+ * Check whether the given base path, e.g.,  /sys/class/misc/tpm0/device,
+ * is the sysfs entry of a TPM. A TPM sysfs entry should be uniquely
+ * recognizable by the file entries 'pcrs' and 'cancel'.
+ * Upon success the basepath with '/cancel' appended is returned, NULL
+ * otherwise.
+ */
+static char *
+virTPMCheckSysfsCancel(char *basepath)
+{
+    char *path = NULL;
+    struct stat statbuf;
+
+    if (virAsprintf(&path, "%s/pcrs", basepath) < 0) {
+        virReportOOMError();
+        goto cleanup;
+    }
+
+    if (stat(path, &statbuf) == -1 || !S_ISREG(statbuf.st_mode)) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("Could not determine TPM cancel path since pcrs "
+                         "file was not found in directory %s"),
+                       basepath);
+        goto cleanup;
+    }
+
+    VIR_FREE(path);
+
+    if (virAsprintf(&path, "%s/cancel", basepath) < 0) {
+        virReportOOMError();
+        goto cleanup;
+    }
+
+    if (stat(path, &statbuf) == -1 || !S_ISREG(statbuf.st_mode)) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("Could not determine TPM cancel path since cancel "
+                         "file was not found in directory %s"),
+                       basepath);
+        goto cleanup;
+    }
+
+    return path;
+
+cleanup:
+    VIR_FREE(path);
+    return NULL;
+}
+
+
+char *
+virTPMFindCancelPath(void)
+{
+    unsigned int idx;
+    DIR *pnp_dir;
+    char *path = NULL, *basepath = NULL;
+    struct dirent *entry;
+
+    pnp_dir = opendir("/sys/class/misc");
+    if (pnp_dir != NULL) {
+        while ((entry = readdir(pnp_dir)) != NULL) {
+            /* expecting 'tpm%u' -- skip other file patterns */
+            if (!STRPREFIX(entry->d_name, "tpm") ||
+                virStrToLong_ui(entry->d_name + strlen("tpm"),
+                                NULL, 10, &idx) < 0)
+                continue;
+            if (virAsprintf(&basepath, "/sys/class/misc/%s/device",
+                            entry->d_name) < 0) {
+                virReportOOMError();
+                break;
+            }
+            if ((path = virTPMCheckSysfsCancel(basepath)))
+                break;
+
+            VIR_FREE(basepath);
+        }
+        closedir(pnp_dir);
+    } else {
+        virReportSystemError(errno, "%s",
+                             _("Could not open directory /sys/class/misc "
+                             "to find TPM cancel path"));
+    }
+
+    VIR_FREE(basepath);
+
+    /* report error if no path was found & no error was reported earlier */
+    if (!path && !virGetLastError())
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       "%s",
+                       _("Could not determine TPM cancel path. You may need "
+                       "to insert the TPM driver module into the kernel"));
+
+    return path;
+}
Index: libvirt/src/libvirt_private.syms
===================================================================
--- libvirt.orig/src/libvirt_private.syms
+++ libvirt/src/libvirt_private.syms
@@ -1781,6 +1781,10 @@ virTimeStringThen;
 virTimeStringThenRaw;
 
 
+# util/virtpm.h
+virTPMFindCancelPath;
+
+
 # util/virtypedparam.h
 virTypedParameterArrayValidate;
 virTypedParameterAssign;
Index: libvirt/src/util/virtpm.h
===================================================================
--- /dev/null
+++ libvirt/src/util/virtpm.h
@@ -0,0 +1,27 @@
+/*
+ * virtpm.h: TPM support
+ *
+ * Copyright (C) 2013 IBM Corporation
+ *
+ * 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/>.
+ *
+ * Author: Stefan Berger <stefanb linux vnet ibm com>
+ */
+#ifndef __VIR_TPM_H__
+# define __VIR_TPM_H__
+
+char *virTPMFindCancelPath(void);
+
+#endif /* __VIR_TPM_H__ */
Index: libvirt/po/POTFILES.in
===================================================================
--- libvirt.orig/po/POTFILES.in
+++ libvirt/po/POTFILES.in
@@ -181,6 +181,7 @@ src/util/virsysinfo.c
 src/util/virerror.c
 src/util/virerror.h
 src/util/virtime.c
+src/util/virtpm.c
 src/util/virtypedparam.c
 src/util/viruri.c
 src/util/virusb.c


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