domaincaps: Expose UEFI binary path, if it exists

Check to see if the UEFI binary mentioned in qemu.conf actually
exists, and if so expose it in domcapabilities like

<loader ...>
  <value>/path/to/ovmf</value>
</loader>

We introduce some generic domcaps infrastructure for handling
a dynamic list of string values, it may be of use for future bits.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>

tests/domaincapsschemadata/domaincaps-full.xml

@@ -6,6 +6,8 @@
   <vcpu max='255'/>
   <os supported='yes'>
     <loader supported='yes'>
+      <value>/foo/bar</value>
+      <value>/tmp/my_path</value>
       <enum name='type'>
         <value>rom</value>
         <value>pflash</value>

tests/domaincapsschemadata/domaincaps-qemu_1.6.50-1.xml

@@ -5,6 +5,7 @@
   <arch>x86_64</arch>
   <os supported='yes'>
     <loader supported='yes'>
+      <value>/usr/share/OVMF/OVMF_CODE.fd</value>
       <enum name='type'>
         <value>rom</value>
         <value>pflash</value>

tests/domaincapstest.c

@@ -34,6 +34,27 @@ typedef int (*virDomainCapsFill)(virDomainCapsPtr domCaps,
 #define SET_ALL_BITS(x) \
     memset(&(x.values), 0xff, sizeof(x.values))
 
+static int ATTRIBUTE_SENTINEL
+fillStringValues(virDomainCapsStringValuesPtr values, ...)
+{
+    int ret = 0;
+    va_list list;
+    const char *str;
+
+    va_start(list, values);
+    while ((str = va_arg(list, const char *))) {
+        if (VIR_REALLOC_N(values->values, values->nvalues + 1) < 0 ||
+            VIR_STRDUP(values->values[values->nvalues], str) < 0) {
+            ret = -1;
+            break;
+        }
+        values->nvalues++;
+    }
+    va_end(list);
+
+    return ret;
+}
+
 static int
 fillAll(virDomainCapsPtr domCaps,
         void *opaque ATTRIBUTE_UNUSED)
@@ -49,6 +70,11 @@ fillAll(virDomainCapsPtr domCaps,
     loader->device.supported = true;
     SET_ALL_BITS(loader->type);
     SET_ALL_BITS(loader->readonly);
+    if (fillStringValues(&loader->values,
+                         "/foo/bar",
+                         "/tmp/my_path",
+                         NULL) < 0)
+        return -1;
 
     disk->device.supported = true;
     SET_ALL_BITS(disk->diskDevice);
@@ -66,13 +92,21 @@ fillAll(virDomainCapsPtr domCaps,
 
 #ifdef WITH_QEMU
 # include "testutilsqemu.h"
+
+struct fillQemuCapsData {
+    virQEMUCapsPtr qemuCaps;
+    virQEMUDriverConfigPtr cfg;
+};
+
 static int
 fillQemuCaps(virDomainCapsPtr domCaps,
              void *opaque)
 {
-    virQEMUCapsPtr qemuCaps = (virQEMUCapsPtr) opaque;
+    struct fillQemuCapsData *data = (struct fillQemuCapsData *) opaque;
+    virQEMUCapsPtr qemuCaps = data->qemuCaps;
+    virQEMUDriverConfigPtr cfg = data->cfg;
 
-    if (virQEMUCapsFillDomainCaps(domCaps, qemuCaps) < 0)
+    if (virQEMUCapsFillDomainCaps(domCaps, qemuCaps, cfg) < 0)
         return -1;
 
     /* The function above tries to query host's KVM & VFIO capabilities by
@@ -97,7 +131,7 @@ buildVirDomainCaps(const char *emulatorbin,
                    virDomainCapsFill fillFunc,
                    void *opaque)
 {
-    virDomainCapsPtr domCaps;
+    virDomainCapsPtr domCaps, ret = NULL;
 
     if (!(domCaps = virDomainCapsNew(emulatorbin, machine, arch, type)))
         goto cleanup;
@@ -107,8 +141,9 @@ buildVirDomainCaps(const char *emulatorbin,
         domCaps = NULL;
     }
 
+    ret = domCaps;
  cleanup:
-    return domCaps;
+    return ret;
 }
 
 struct test_virDomainCapsFormatData {
@@ -182,13 +217,16 @@ mymain(void)
 
 #ifdef WITH_QEMU
 
+    virQEMUDriverConfigPtr cfg = virQEMUDriverConfigNew(false);
+
 # define DO_TEST_QEMU(Filename, QemuCapsFile, Emulatorbin, Machine, Arch, Type, ...)    \
     do {                                                                                \
         const char *capsPath = abs_srcdir "/qemucapabilitiesdata/" QemuCapsFile ".caps";    \
         virQEMUCapsPtr qemuCaps = qemuTestParseCapabilities(capsPath);                  \
+        struct fillQemuCapsData fillData = {.qemuCaps = qemuCaps, .cfg = cfg};          \
         struct test_virDomainCapsFormatData data = {.filename = Filename,               \
             .emulatorbin = Emulatorbin, .machine = Machine, .arch = Arch,               \
-            .type = Type, .fillFunc = fillQemuCaps, .opaque = qemuCaps};                \
+            .type = Type, .fillFunc = fillQemuCaps, .opaque = &fillData};               \
         if (!qemuCaps) {                                                                \
             fprintf(stderr, "Unable to build qemu caps from %s\n", capsPath);           \
             ret = -1;                                                                   \
@@ -199,6 +237,7 @@ mymain(void)
     DO_TEST_QEMU("qemu_1.6.50-1", "caps_1.6.50-1", "/usr/bin/qemu-system-x86_64",
                  "pc-1.2",  VIR_ARCH_X86_64, VIR_DOMAIN_VIRT_KVM);
 
+    virObjectUnref(cfg);
 #endif /* WITH_QEMU */
 
     return ret;