util: helper functions for fibre channel devices

We will need some convenient helper functions for managing sysfs-entries
for fibre channel-backed devices. Let's implement them and make them
available in the private API.

Signed-off-by: Bjoern Walk <bwalk@linux.vnet.ibm.com>

po/POTFILES.in

@@ -206,6 +206,7 @@ src/util/virdnsmasq.c
 src/util/virerror.c
 src/util/virerror.h
 src/util/vireventpoll.c
+src/util/virfcp.c
 src/util/virfdstream.c
 src/util/virfile.c
 src/util/virfirewall.c

src/Makefile.am

@@ -117,6 +117,7 @@ UTIL_SOURCES =							\
 		util/virerror.c util/virerror.h			\
 		util/virevent.c util/virevent.h			\
 		util/vireventpoll.c util/vireventpoll.h		\
+		util/virfcp.c util/virfcp.h			\
 		util/virfdstream.c util/virfdstream.h		\
 		util/virfile.c util/virfile.h			\
 		util/virfirewall.c util/virfirewall.h		\

src/libvirt_private.syms

@@ -1586,6 +1586,11 @@ virEventPollUpdateHandle;
 virEventPollUpdateTimeout;
 
 
+# util/virfcp.h
+virFCIsCapableRport;
+virFCReadRportValue;
+
+
 # util/virfdstream.h
 virFDStreamConnectUNIX;
 virFDStreamCreateFile;

src/util/virfcp.c

@@ -0,0 +1,98 @@
+/*
+ * virfcp.c: Utility functions for the Fibre Channel Protocol
+ *
+ * Copyright (C) 2017 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: Bjoern Walk <bwalk@linux.vnet.ibm.com>
+ */
+
+#include <config.h>
+
+#include "internal.h"
+
+#include "viralloc.h"
+#include "virfile.h"
+#include "virstring.h"
+
+#include "virfcp.h"
+
+#define VIR_FROM_THIS VIR_FROM_NONE
+
+#ifdef __linux__
+
+# define SYSFS_FC_RPORT_PATH "/sys/class/fc_remote_ports"
+
+bool
+virFCIsCapableRport(const char *rport)
+{
+    bool ret = false;
+    char *path = NULL;
+
+    if (virBuildPath(&path, SYSFS_FC_RPORT_PATH, rport) < 0)
+        return false;
+
+    ret = virFileExists(path);
+    VIR_FREE(path);
+
+    return ret;
+}
+
+int
+virFCReadRportValue(const char *rport,
+                    const char *entry,
+                    char **result)
+{
+    int ret = -1;
+    char *buf = NULL, *p = NULL;
+
+    if (virFileReadValueString(&buf, "%s/%s/%s",
+                               SYSFS_FC_RPORT_PATH, rport, entry) < 0) {
+        return -1;
+    }
+
+    if ((p = strchr(buf, '\n')))
+        *p = '\0';
+
+    if (VIR_STRDUP(*result, buf) < 0)
+        goto cleanup;
+
+    ret = 0;
+
+ cleanup:
+    VIR_FREE(buf);
+    return ret;
+}
+
+#else
+
+bool
+virSysfsIsCapableFCRport(const char *rport ATTRIBUTE_UNUSED)
+{
+    virReportSystemError(ENOSYS, "%s", _("Not supported on this platform"));
+    return false;
+}
+
+int
+virSysfsReadFCRport(const char *rport ATTRIBUTE_UNUSED,
+                    const char *entry ATTRIBUTE_UNUSED,
+                    char **result ATTRIBUTE_UNUSED)
+{
+    virReportSystemError(ENOSYS, "%s", _("Not supported on this platform"));
+    return -1;
+}
+
+#endif

src/util/virfcp.h

@@ -0,0 +1,34 @@
+/*
+ * virfcp.h: Utility functions for the Fibre Channel Protocol
+ *
+ * Copyright (C) 2017 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: Bjoern Walk <bwalk@linux.vnet.ibm.com>
+ */
+
+#ifndef __VIR_FCP_H__
+# define __VIR_FCP_H__
+
+bool
+virFCIsCapableRport(const char *rport);
+
+int
+virFCReadRportValue(const char *rport,
+                    const char *entry,
+                    char **result);
+
+#endif