tests: Support for faking emulator in qemuxml2argv

This patch allows for using custom scripts instead of /usr/bin/qemu
emulator in domain XML. To do so, one would specify relative path to the
custom script in <emulator/>. The path needs to be relative to
qemuxml2argvdata directory and it will be transparently made absolute in
runtime. The expected command line needs to contain the exact relative
path as was used in domain XML.

The problem is RelaxNG schema for domain XML only allows for absolute
path within <emulator/>. To workaround it, an extra '/' must be added at
the beginning of the path. That is, instead of "./qemu.sh" or
"../emulator/qemu.sh" one would use "/./qemu.sh" or
"/../emulator/qemu.sh". The extra slash is removed before further
processing. I don't like this workaround, it's very ugly but it's the
best option I was able to come up with. Relaxing domain XML schema is
not an option IMO.

diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
index e6174be26b5058841ebef885f90fc5c15fcbdd1d..d2b5e249915c35fd22e67fe5aaa4a30ba139f2bb 100644 (file)
--- a/tests/qemuxml2argvtest.c
+++ b/tests/qemuxml2argvtest.c
@@ -41,6 +41,7 @@ static int testCompareXMLToArgvFiles(const char *xml,
     virDomainChrDef monitor_chr;
     virConnectPtr conn;
     char *log = NULL;
+    char *emulator = NULL;
 
     if (!(conn = virGetConnect()))
         goto fail;
@@ -52,6 +53,26 @@ static int testCompareXMLToArgvFiles(const char *xml,
                                         VIR_DOMAIN_XML_INACTIVE)))
         goto fail;
 
+    /*
+     * For test purposes, we may want to fake emulator's output by providing
+     * our own script instead of a real emulator. For this to work we need to
+     * specify a relative path in <emulator/> element, which, however, is not
+     * allowed by RelaxNG schema for domain XML. To work around it we add an
+     * extra '/' at the beginning of relative emulator path so that it looks
+     * like, e.g., "/./qemu.sh" or "/../emulator/qemu.sh" instead of
+     * "./qemu.sh" or "../emulator/qemu.sh" respectively. The following code
+     * detects such paths, strips the extra '/' and makes the path absolute.
+     */
+    if (vmdef->emulator && STRPREFIX(vmdef->emulator, "/.")) {
+        if (!(emulator = strdup(vmdef->emulator + 1)))
+            goto fail;
+        free(vmdef->emulator);
+        vmdef->emulator = NULL;
+        if (virAsprintf(&vmdef->emulator, "%s/qemuxml2argvdata/%s",
+                        abs_srcdir, emulator) < 0)
+            goto fail;
+    }
+
     if (extraFlags & QEMUD_CMD_FLAG_DOMID)
         vmdef->id = 6;
     else
@@ -104,6 +125,12 @@ static int testCompareXMLToArgvFiles(const char *xml,
         virResetLastError();
     }
 
+    if (emulator && *argv) {
+        free(*(char**) argv);
+        *argv = emulator;
+        emulator = NULL;
+    }
+
     len = 1; /* for trailing newline */
     tmp = qenv;
     while (*tmp) {
@@ -144,6 +171,7 @@ static int testCompareXMLToArgvFiles(const char *xml,
 
  fail:
     free(log);
+    free(emulator);
     free(actualargv);
     if (argv) {
         tmp = argv;