util: pci: Introduce virPCIGetMdevTypes helper

This is a replacement for the existing udevPCIGetMdevTypesCap which is
static to the udev backend. This simple helper constructs the sysfs path
from the device's base path for each mdev type and queries the
corresponding attributes of that type.

Signed-off-by: Erik Skultety <eskultet@redhat.com>

src/libvirt_private.syms

@@ -2457,6 +2457,7 @@ virPCIDeviceWaitForCleanup;
 virPCIEDeviceInfoFree;
 virPCIGetDeviceAddressFromSysfsLink;
 virPCIGetHeaderType;
+virPCIGetMdevTypes;
 virPCIGetNetName;
 virPCIGetPhysicalFunction;
 virPCIGetVirtualFunctionIndex;

src/util/virpci.c

@@ -3027,6 +3027,64 @@ virPCIGetVirtualFunctionInfo(const char *vf_sysfs_device_path,
     return ret;
 }
 
+
+ssize_t
+virPCIGetMdevTypes(const char *sysfspath,
+                   virMediatedDeviceTypePtr **types)
+{
+    ssize_t ret = -1;
+    int dirret = -1;
+    DIR *dir = NULL;
+    struct dirent *entry;
+    char *types_path = NULL;
+    char *tmppath = NULL;
+    virMediatedDeviceTypePtr mdev_type = NULL;
+    virMediatedDeviceTypePtr *mdev_types = NULL;
+    size_t ntypes = 0;
+    size_t i;
+
+    if (virAsprintf(&types_path, "%s/mdev_supported_types", sysfspath) < 0)
+        return -1;
+
+    if ((dirret = virDirOpenIfExists(&dir, types_path)) < 0)
+        goto cleanup;
+
+    if (dirret == 0) {
+        ret = 0;
+        goto cleanup;
+    }
+
+    while ((dirret = virDirRead(dir, &entry, types_path)) > 0) {
+        /* append the type id to the path and read the attributes from there */
+        if (virAsprintf(&tmppath, "%s/%s", types_path, entry->d_name) < 0)
+            goto cleanup;
+
+        if (virMediatedDeviceTypeReadAttrs(tmppath, &mdev_type) < 0)
+            goto cleanup;
+
+        if (VIR_APPEND_ELEMENT(mdev_types, ntypes, mdev_type) < 0)
+            goto cleanup;
+
+        VIR_FREE(tmppath);
+    }
+
+    if (dirret < 0)
+        goto cleanup;
+
+    VIR_STEAL_PTR(*types, mdev_types);
+    ret = ntypes;
+    ntypes = 0;
+ cleanup:
+    virMediatedDeviceTypeFree(mdev_type);
+    for (i = 0; i < ntypes; i++)
+        virMediatedDeviceTypeFree(mdev_types[i]);
+    VIR_FREE(mdev_types);
+    VIR_FREE(types_path);
+    VIR_FREE(tmppath);
+    VIR_DIR_CLOSE(dir);
+    return ret;
+}
+
 #else
 static const char *unsupported = N_("not supported on non-linux platforms");
 

src/util/virpci.h

@@ -25,6 +25,7 @@
 # define __VIR_PCI_H__
 
 # include "internal.h"
+# include "virmdev.h"
 # include "virobject.h"
 # include "virutil.h"
 
@@ -249,4 +250,7 @@ int virPCIGetHeaderType(virPCIDevicePtr dev, int *hdrType);
 
 void virPCIEDeviceInfoFree(virPCIEDeviceInfoPtr dev);
 
+ssize_t virPCIGetMdevTypes(const char *sysfspath,
+                           virMediatedDeviceType ***types);
+
 #endif /* __VIR_PCI_H__ */