logging: preserve driver, dom name & uuid against log file

The virt driver, dom name and uuid associated with a log
file are important pieces of metadata to keep around for
sake of future enhancements to virtlogd. Currently we
discard them after opening the log file, but we should
preserve them, even across restarts.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

src/logging/log_handler.c

@@ -30,6 +30,7 @@
 #include "virstring.h"
 #include "virlog.h"
 #include "virrotatingfile.h"
+#include "viruuid.h"
 
 #include <unistd.h>
 #include <fcntl.h>
@@ -51,6 +52,10 @@ struct _virLogHandlerLogFile {
     virRotatingFileWriterPtr file;
     int watch;
     int pipefd; /* Read from QEMU via this */
+
+    char *driver;
+    unsigned char domuuid[VIR_UUID_BUFLEN];
+    char *domname;
 };
 
 struct _virLogHandler {
@@ -93,6 +98,9 @@ virLogHandlerLogFileFree(virLogHandlerLogFilePtr file)
 
     if (file->watch != -1)
         virEventRemoveHandle(file->watch);
+
+    VIR_FREE(file->driver);
+    VIR_FREE(file->domname);
     VIR_FREE(file);
 }
 
@@ -204,6 +212,8 @@ virLogHandlerLogFilePostExecRestart(virLogHandlerPtr handler,
 {
     virLogHandlerLogFilePtr file;
     const char *path;
+    const char *domuuid;
+    const char *tmp;
 
     if (VIR_ALLOC(file) < 0)
         return NULL;
@@ -212,7 +222,34 @@ virLogHandlerLogFilePostExecRestart(virLogHandlerPtr handler,
 
     if ((path = virJSONValueObjectGetString(object, "path")) == NULL) {
         virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
-                       _("Missing file path in JSON document"));
+                       _("Missing 'path' field in JSON document"));
+        goto error;
+    }
+
+    if ((tmp = virJSONValueObjectGetString(object, "driver")) == NULL) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("Missing 'driver' in JSON document"));
+        goto error;
+    }
+    if (VIR_STRDUP(file->driver, tmp) < 0)
+        goto error;
+
+    if ((tmp = virJSONValueObjectGetString(object, "domname")) == NULL) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("Missing 'domname' in JSON document"));
+        goto error;
+    }
+    if (VIR_STRDUP(file->domname, tmp) < 0)
+        goto error;
+
+    if ((domuuid = virJSONValueObjectGetString(object, "domuuid")) == NULL) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("Missing 'domuuid' in JSON document"));
+        goto error;
+    }
+    if (virUUIDParse(domuuid, file->domuuid) < 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("Malformed 'domuuid' in JSON document"));
         goto error;
     }
 
@@ -225,7 +262,7 @@ virLogHandlerLogFilePostExecRestart(virLogHandlerPtr handler,
 
     if (virJSONValueObjectGetNumberInt(object, "pipefd", &file->pipefd) < 0) {
         virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
-                       _("Missing file pipefd in JSON document"));
+                       _("Missing 'pipefd' in JSON document"));
         goto error;
     }
     if (virSetInherit(file->pipefd, false) < 0) {
@@ -347,7 +384,7 @@ virLogHandlerGetLogFilePathForDomain(virLogHandlerPtr handler,
 int
 virLogHandlerDomainOpenLogFile(virLogHandlerPtr handler,
                                const char *driver,
-                               const unsigned char *domuuid ATTRIBUTE_UNUSED,
+                               const unsigned char *domuuid,
                                const char *domname,
                                ino_t *inode,
                                off_t *offset)
@@ -388,6 +425,10 @@ virLogHandlerDomainOpenLogFile(virLogHandlerPtr handler,
     file->watch = -1;
     file->pipefd = pipefd[0];
     pipefd[0] = -1;
+    memcpy(file->domuuid, domuuid, VIR_UUID_BUFLEN);
+    if (VIR_STRDUP(file->driver, driver) < 0 ||
+        VIR_STRDUP(file->domname, domname) < 0)
+        goto error;
 
     if ((file->file = virRotatingFileWriterNew(path,
                                                DEFAULT_FILE_SIZE,
@@ -531,6 +572,7 @@ virLogHandlerPreExecRestart(virLogHandlerPtr handler)
     virJSONValuePtr ret = virJSONValueNewObject();
     virJSONValuePtr files;
     size_t i;
+    char domuuid[VIR_UUID_STRING_BUFLEN];
 
     if (!ret)
         return NULL;
@@ -561,6 +603,18 @@ virLogHandlerPreExecRestart(virLogHandlerPtr handler)
                                            virRotatingFileWriterGetPath(handler->files[i]->file)) < 0)
             goto error;
 
+        if (virJSONValueObjectAppendString(file, "driver",
+                                           handler->files[i]->driver) < 0)
+            goto error;
+
+        if (virJSONValueObjectAppendString(file, "domname",
+                                           handler->files[i]->domname) < 0)
+            goto error;
+
+        virUUIDFormat(handler->files[i]->domuuid, domuuid);
+        if (virJSONValueObjectAppendString(file, "domuuid", domuuid) < 0)
+            goto error;
+
         if (virSetInherit(handler->files[i]->pipefd, true) < 0) {
             virReportSystemError(errno, "%s",
                                  _("Cannot disable close-on-exec flag"));