[libvirt] [PATCH v2 6/8] logging: support truncation of logfiles when opening

[Daniel P. Berrange]

The virtlogd daemon currently opens all files for append, but
in some cases the user may wish to discard existing data. Define
a new flag to indicate that logfiles should be truncated when
opening.
---
 src/logging/log_daemon_dispatch.c | 3 ++-
 src/logging/log_handler.c         | 6 ++----
 src/logging/log_handler.h         | 2 +-
 src/logging/log_manager.h         | 2 ++
 src/logging/log_protocol.x        | 4 ++++
 5 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/src/logging/log_daemon_dispatch.c b/src/logging/log_daemon_dispatch.c
index a5fa7f0..b00cee2 100644
--- a/src/logging/log_daemon_dispatch.c
+++ b/src/logging/log_daemon_dispatch.c
@@ -50,13 +50,14 @@ virLogManagerProtocolDispatchDomainOpenLogFile(virNetServerPtr server ATTRIBUTE_
     int rv = -1;
     off_t offset;
     ino_t inode;
+    bool trunc = args->flags & VIR_LOG_MANAGER_PROTOCOL_DOMAIN_OPEN_LOG_FILE_TRUNCATE;
 
     if ((fd = virLogHandlerDomainOpenLogFile(virLogDaemonGetHandler(logDaemon),
                                              args->driver,
                                              (unsigned char *)args->dom.uuid,
                                              args->dom.name,
                                              args->path,
-                                             args->flags,
+                                             trunc,
                                              &inode, &offset)) < 0)
         goto cleanup;
 
diff --git a/src/logging/log_handler.c b/src/logging/log_handler.c
index 92cff50..4c08223 100644
--- a/src/logging/log_handler.c
+++ b/src/logging/log_handler.c
@@ -357,7 +357,7 @@ virLogHandlerDomainOpenLogFile(virLogHandlerPtr handler,
                                const unsigned char *domuuid,
                                const char *domname,
                                const char *path,
-                               unsigned int flags,
+                               bool trunc,
                                ino_t *inode,
                                off_t *offset)
 {
@@ -365,8 +365,6 @@ virLogHandlerDomainOpenLogFile(virLogHandlerPtr handler,
     virLogHandlerLogFilePtr file = NULL;
     int pipefd[2] = { -1, -1 };
 
-    virCheckFlags(0, -1);
-
     virObjectLock(handler);
 
     handler->inhibitor(true, handler->opaque);
@@ -400,7 +398,7 @@ virLogHandlerDomainOpenLogFile(virLogHandlerPtr handler,
     if ((file->file = virRotatingFileWriterNew(path,
                                                DEFAULT_FILE_SIZE,
                                                DEFAULT_MAX_BACKUP,
-                                               false,
+                                               trunc,
                                                DEFAULT_MODE)) == NULL)
         goto error;
 
diff --git a/src/logging/log_handler.h b/src/logging/log_handler.h
index e61f32d..54a9cd9 100644
--- a/src/logging/log_handler.h
+++ b/src/logging/log_handler.h
@@ -48,7 +48,7 @@ int virLogHandlerDomainOpenLogFile(virLogHandlerPtr handler,
                                    const unsigned char *domuuid,
                                    const char *domname,
                                    const char *path,
-                                   unsigned int flags,
+                                   bool trunc,
                                    ino_t *inode,
                                    off_t *offset);
 
diff --git a/src/logging/log_manager.h b/src/logging/log_manager.h
index d3b9d29..7deaba7 100644
--- a/src/logging/log_manager.h
+++ b/src/logging/log_manager.h
@@ -26,6 +26,8 @@
 
 # include "internal.h"
 
+# include "logging/log_protocol.h"
+
 typedef struct _virLogManager virLogManager;
 typedef virLogManager *virLogManagerPtr;
 
diff --git a/src/logging/log_protocol.x b/src/logging/log_protocol.x
index b0ac31b..0363c75 100644
--- a/src/logging/log_protocol.x
+++ b/src/logging/log_protocol.x
@@ -30,6 +30,10 @@ struct virLogManagerProtocolLogFilePosition {
 };
 typedef struct virLogManagerProtocolLogFilePosition virLogManagerProtocolLogFilePosition;
 
+enum virLogManagerProtocolDomainOpenLogFileFlags {
+    VIR_LOG_MANAGER_PROTOCOL_DOMAIN_OPEN_LOG_FILE_TRUNCATE = 1
+};
+
 /* Obtain a file handle suitable for writing to a
  * log file for a domain
  */
-- 
2.5.0