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Re: [libvirt] [PATCH v3 04/11] Helper functions for host TPM support





On 03/21/2013 11:42 AM, Stefan Berger wrote:
Signed-off-by: Stefan Berger<stefanb linux vnet ibm com>

---
  po/POTFILES.in           |    1
  src/Makefile.am          |    1
  src/libvirt_private.syms |    4 +
  src/util/virtpm.c        |  124 +++++++++++++++++++++++++++++++++++++++++++++++
  src/util/virtpm.h        |   27 ++++++++++
  5 files changed, 157 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 +1,124 @@
+/*
+ * 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 "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 'true' is returned and the basebath buffer has '/cancel'

s/basebath/basepath

+ * appended.
+ */
+static bool
+virTPMCheckSysfsCancel(char *basepath, size_t bufsz)
+{
+    char *path = NULL;
+    struct stat statbuf;
+
+    if (virAsprintf(&path, "%s/pcrs", basepath) < 0) {
+        virReportOOMError();
+        goto error;
+    }
+    if (stat(path, &statbuf) == -1 || !S_ISREG(statbuf.st_mode))
+        goto error;
+
+    VIR_FREE(path);
+
+    if (virAsprintf(&path, "%s/cancel", basepath) < 0) {
+        virReportOOMError();
+        goto error;
+    }
+
+    if (stat(path, &statbuf) == -1 || !S_ISREG(statbuf.st_mode))
+        goto error;
+
+    if (!virStrncpy(basepath, path, strlen(path) + 1, bufsz)) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("Basepath buffer is too small"));
+        goto error;
+    }
+
+    VIR_FREE(path);
+
+    return true;
+
+error:
+    VIR_FREE(path);
+    return false;
+}
+
+
+char *
+virTPMFindCancelPath(void)
+{
+    unsigned int idx;
+    int len;
+    DIR *pnp_dir;
+    char path[100], *p;

Is there any reason not to use PATH_MAX instead of 100 here?

+    struct dirent entry, *result;
+    bool found = false;
+
+    snprintf(path, sizeof(path), "/sys/class/misc");
+    pnp_dir = opendir(path);
+    if (pnp_dir != NULL) {
+        while (readdir_r(pnp_dir, &entry, &result) == 0 &&
+               result != NULL) {
+            if (sscanf(entry.d_name, "tpm%u%n", &idx, &len) < 1 ||
+                len <= strlen("tpm") ||
+                len != strlen(entry.d_name)) {
+                continue;
+            }
+            snprintf(path, sizeof(path), "/sys/class/misc/%s/device",
+                     entry.d_name);
+            if (!virTPMCheckSysfsCancel(path, sizeof(path))) {
+                continue;
+            }
+
+            found = true;
+            break;
+        }
+        closedir(pnp_dir);
+    }
+
+    if (found) {
+        if (!(p = strdup(path)))
+            virReportOOMError();
+        return p;
+    }
+
+    return NULL;
+}
Index: libvirt/src/libvirt_private.syms
===================================================================
--- libvirt.orig/src/libvirt_private.syms
+++ libvirt/src/libvirt_private.syms
@@ -1772,6 +1772,10 @@ 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


--
Regards,
Corey Bryant


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