[PATCH v1] virdnsmasq: fix runtime search for executable

[Olaf Hering <olaf@xxxxxxxxx>]

dnsmasq is an optional binary which does not neccessary exist during build.

Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>
---
 src/util/virdnsmasq.c | 28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/src/util/virdnsmasq.c b/src/util/virdnsmasq.c
index f2f606913f..06d192c99d 100644
--- a/src/util/virdnsmasq.c
+++ b/src/util/virdnsmasq.c
@@ -729,8 +729,26 @@ dnsmasqCapsRefreshInternal(dnsmasqCaps *caps, bool force)
     return ret;
 }
 
+static char *
+dnsmasqGetBinaryPath(void)
+{
+    static const char binary[] = DNSMASQ;
+    char *binary_path;
+
+    if (g_path_is_absolute(binary))
+        return g_strdup(binary);
+
+    binary_path = virFindFileInPath(binary);
+    if (!binary_path) {
+        virReportSystemError(ENOENT, _("Cannot find '%s' in path"), binary);
+        binary_path = g_strdup(binary);
+    }
+
+    return binary_path;
+}
+
 static dnsmasqCaps *
-dnsmasqCapsNewEmpty(const char *binaryPath)
+dnsmasqCapsNewEmpty(void)
 {
     dnsmasqCaps *caps;
 
@@ -739,14 +757,14 @@ dnsmasqCapsNewEmpty(const char *binaryPath)
     if (!(caps = virObjectNew(dnsmasqCapsClass)))
         return NULL;
     caps->flags = virBitmapNew(DNSMASQ_CAPS_LAST);
-    caps->binaryPath = g_strdup(binaryPath ? binaryPath : DNSMASQ);
+    caps->binaryPath = dnsmasqGetBinaryPath();
     return caps;
 }
 
 dnsmasqCaps *
 dnsmasqCapsNewFromBuffer(const char *buf)
 {
-    dnsmasqCaps *caps = dnsmasqCapsNewEmpty(DNSMASQ);
+    dnsmasqCaps *caps = dnsmasqCapsNewEmpty();
 
     if (!caps)
         return NULL;
@@ -761,7 +779,7 @@ dnsmasqCapsNewFromBuffer(const char *buf)
 dnsmasqCaps *
 dnsmasqCapsNewFromBinary(void)
 {
-    dnsmasqCaps *caps = dnsmasqCapsNewEmpty(DNSMASQ);
+    dnsmasqCaps *caps = dnsmasqCapsNewEmpty();
 
     if (!caps)
         return NULL;
@@ -776,7 +794,7 @@ dnsmasqCapsNewFromBinary(void)
 const char *
 dnsmasqCapsGetBinaryPath(dnsmasqCaps *caps)
 {
-    return caps ? caps->binaryPath : DNSMASQ;
+    return caps ? caps->binaryPath : dnsmasqGetBinaryPath();
 }
 
 unsigned long