tpm: Move qemuTPMEmulatorInit to virTPMEmulatorInit in virtpm.c

Move qemuTPMEmulatorInit to virTPMEmulatorInit in virtpm.c and introduce
a few functions to query the executables needed for virCommands.

Add locking to protect the tool paths and return a copy of the tool paths
to callers wanting to access them so that we can run the initialization
function multiples time later on and detect when the executable gets updated.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

src/libvirt_private.syms

@@ -3177,6 +3177,10 @@ virTimeStringThenRaw;
 
 # util/virtpm.h
 virTPMCreateCancelPath;
+virTPMEmulatorInit;
+virTPMGetSwtpm;
+virTPMGetSwtpmIoctl;
+virTPMGetSwtpmSetup;
 
 
 # util/virtypedparam.h

src/qemu/qemu_tpm.c

@@ -41,79 +41,12 @@
 #include "configmake.h"
 #include "dirname.h"
 #include "qemu_tpm.h"
+#include "virtpm.h"
 
 #define VIR_FROM_THIS VIR_FROM_NONE
 
 VIR_LOG_INIT("qemu.tpm");
 
-/*
- * executables for the swtpm; to be found on the host
- */
-static char *swtpm_path;
-static char *swtpm_setup;
-static char *swtpm_ioctl;
-
-/*
- * qemuTPMEmulatorInit
- *
- * Initialize the Emulator functions by searching for necessary
- * executables that we will use to start and setup the swtpm
- */
-static int
-qemuTPMEmulatorInit(void)
-{
-    if (!swtpm_path) {
-        swtpm_path = virFindFileInPath("swtpm");
-        if (!swtpm_path) {
-            virReportSystemError(ENOENT, "%s",
-                                 _("Unable to find 'swtpm' binary in $PATH"));
-            return -1;
-        }
-        if (!virFileIsExecutable(swtpm_path)) {
-            virReportError(VIR_ERR_INTERNAL_ERROR,
-                           _("TPM emulator %s is not an executable"),
-                           swtpm_path);
-            VIR_FREE(swtpm_path);
-            return -1;
-        }
-    }
-
-    if (!swtpm_setup) {
-        swtpm_setup = virFindFileInPath("swtpm_setup");
-        if (!swtpm_setup) {
-            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
-                           _("Could not find 'swtpm_setup' in PATH"));
-            return -1;
-        }
-        if (!virFileIsExecutable(swtpm_setup)) {
-            virReportError(VIR_ERR_INTERNAL_ERROR,
-                           _("'%s' is not an executable"),
-                           swtpm_setup);
-            VIR_FREE(swtpm_setup);
-            return -1;
-        }
-    }
-
-    if (!swtpm_ioctl) {
-        swtpm_ioctl = virFindFileInPath("swtpm_ioctl");
-        if (!swtpm_ioctl) {
-            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
-                           _("Could not find swtpm_ioctl in PATH"));
-            return -1;
-        }
-        if (!virFileIsExecutable(swtpm_ioctl)) {
-            virReportError(VIR_ERR_INTERNAL_ERROR,
-                           _("swtpm_ioctl program %s is not an executable"),
-                           swtpm_ioctl);
-            VIR_FREE(swtpm_ioctl);
-            return -1;
-        }
-    }
-
-    return 0;
-}
-
-
 /*
  * qemuTPMCreateEmulatorStoragePath
  *
@@ -345,12 +278,13 @@ qemuTPMEmulatorGetPid(const char *swtpmStateDir,
                       pid_t *pid)
 {
     int ret;
+    VIR_AUTOFREE(char *) swtpm = virTPMGetSwtpm();
     char *pidfile = qemuTPMEmulatorCreatePidFilename(swtpmStateDir,
                                                      shortName);
     if (!pidfile)
         return -ENOMEM;
 
-    ret = virPidFileReadPathIfAlive(pidfile, pid, swtpm_path);
+    ret = virPidFileReadPathIfAlive(pidfile, pid, swtpm);
 
     VIR_FREE(pidfile);
 
@@ -386,7 +320,7 @@ qemuTPMEmulatorPrepareHost(virDomainTPMDefPtr tpm,
 {
     int ret = -1;
 
-    if (qemuTPMEmulatorInit() < 0)
+    if (virTPMEmulatorInit() < 0)
         return -1;
 
     /* create log dir ... allow 'tss' user to cd into it */
@@ -471,6 +405,10 @@ qemuTPMEmulatorRunSetup(const char *storagepath,
     int ret = -1;
     char uuid[VIR_UUID_STRING_BUFLEN];
     char *vmid = NULL;
+    VIR_AUTOFREE(char *)swtpm_setup = virTPMGetSwtpmSetup();
+
+    if (!swtpm_setup)
+        return -1;
 
     if (!privileged && tpmversion == VIR_DOMAIN_TPM_VERSION_1_2)
         return virFileWriteStr(logfile,
@@ -562,6 +500,10 @@ qemuTPMEmulatorBuildCommand(virDomainTPMDefPtr tpm,
     virCommandPtr cmd = NULL;
     bool created = false;
     char *pidfile;
+    VIR_AUTOFREE(char *) swtpm = virTPMGetSwtpm();
+
+    if (!swtpm)
+        return NULL;
 
     if (qemuTPMCreateEmulatorStorage(tpm->data.emulator.storagepath,
                                      &created, swtpm_user, swtpm_group) < 0)
@@ -575,7 +517,7 @@ qemuTPMEmulatorBuildCommand(virDomainTPMDefPtr tpm,
 
     unlink(tpm->data.emulator.source.data.nix.path);
 
-    cmd = virCommandNew(swtpm_path);
+    cmd = virCommandNew(swtpm);
     if (!cmd)
         goto error;
 
@@ -639,8 +581,12 @@ qemuTPMEmulatorStop(const char *swtpmStateDir,
     virCommandPtr cmd;
     char *pathname;
     char *errbuf = NULL;
+    VIR_AUTOFREE(char *) swtpm_ioctl = virTPMGetSwtpmIoctl();
 
-    if (qemuTPMEmulatorInit() < 0)
+    if (!swtpm_ioctl)
+        return;
+
+    if (virTPMEmulatorInit() < 0)
         return;
 
     if (!(pathname = qemuTPMCreateEmulatorSocket(swtpmStateDir, shortName)))

src/util/virtpm.c

@@ -72,3 +72,125 @@ virTPMCreateCancelPath(const char *devpath)
  cleanup:
     return path;
 }
+
+/*
+ * executables for the swtpm; to be found on the host
+ */
+static virMutex swtpm_tools_lock = VIR_MUTEX_INITIALIZER;
+static char *swtpm_path;
+static char *swtpm_setup;
+static char *swtpm_ioctl;
+
+char *
+virTPMGetSwtpm(void)
+{
+    char *s;
+
+    if (!swtpm_path && virTPMEmulatorInit() < 0)
+        return NULL;
+
+    virMutexLock(&swtpm_tools_lock);
+    ignore_value(VIR_STRDUP(s, swtpm_path));
+    virMutexUnlock(&swtpm_tools_lock);
+
+    return s;
+}
+
+char *
+virTPMGetSwtpmSetup(void)
+{
+    char *s;
+
+    if (!swtpm_setup && virTPMEmulatorInit() < 0)
+        return NULL;
+
+    virMutexLock(&swtpm_tools_lock);
+    ignore_value(VIR_STRDUP(s, swtpm_setup));
+    virMutexUnlock(&swtpm_tools_lock);
+
+    return s;
+}
+
+char *
+virTPMGetSwtpmIoctl(void)
+{
+    char *s;
+
+    if (!swtpm_ioctl && virTPMEmulatorInit() < 0)
+        return NULL;
+
+    virMutexLock(&swtpm_tools_lock);
+    ignore_value(VIR_STRDUP(s, swtpm_ioctl));
+    virMutexUnlock(&swtpm_tools_lock);
+
+    return s;
+}
+
+/*
+ * virTPMEmulatorInit
+ *
+ * Initialize the Emulator functions by searching for necessary
+ * executables that we will use to start and setup the swtpm
+ */
+int
+virTPMEmulatorInit(void)
+{
+    int ret = -1;
+
+    virMutexLock(&swtpm_tools_lock);
+
+    if (!swtpm_path) {
+        swtpm_path = virFindFileInPath("swtpm");
+        if (!swtpm_path) {
+            virReportSystemError(ENOENT, "%s",
+                                 _("Unable to find 'swtpm' binary in $PATH"));
+            goto cleanup;
+        }
+        if (!virFileIsExecutable(swtpm_path)) {
+            virReportError(VIR_ERR_INTERNAL_ERROR,
+                           _("TPM emulator %s is not an executable"),
+                           swtpm_path);
+            VIR_FREE(swtpm_path);
+            goto cleanup;
+        }
+    }
+
+    if (!swtpm_setup) {
+        swtpm_setup = virFindFileInPath("swtpm_setup");
+        if (!swtpm_setup) {
+            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                           _("Could not find 'swtpm_setup' in PATH"));
+            goto cleanup;
+        }
+        if (!virFileIsExecutable(swtpm_setup)) {
+            virReportError(VIR_ERR_INTERNAL_ERROR,
+                           _("'%s' is not an executable"),
+                           swtpm_setup);
+            VIR_FREE(swtpm_setup);
+            goto cleanup;
+        }
+    }
+
+    if (!swtpm_ioctl) {
+        swtpm_ioctl = virFindFileInPath("swtpm_ioctl");
+        if (!swtpm_ioctl) {
+            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                           _("Could not find swtpm_ioctl in PATH"));
+            goto cleanup;
+        }
+        if (!virFileIsExecutable(swtpm_ioctl)) {
+            virReportError(VIR_ERR_INTERNAL_ERROR,
+                           _("swtpm_ioctl program %s is not an executable"),
+                           swtpm_ioctl);
+            VIR_FREE(swtpm_ioctl);
+            goto cleanup;
+        }
+    }
+
+    ret = 0;
+
+ cleanup:
+    virMutexUnlock(&swtpm_tools_lock);
+
+    return ret;
+}

src/util/virtpm.h

@@ -21,3 +21,8 @@
 #pragma once
 
 char *virTPMCreateCancelPath(const char *devpath) ATTRIBUTE_NOINLINE;
+
+char *virTPMGetSwtpm(void);
+char *virTPMGetSwtpmSetup(void);
+char *virTPMGetSwtpmIoctl(void);
+int virTPMEmulatorInit(void);