Use VERSION_FILE env variable to define opentitantool version

The version file path is configurable instead of a hard-coded path in
version.rs.

There is an existing bazel label to grab the OT version information.

Change-Id: I0fc8d456223787cf4e324515edb4c1c3e2178a97

sw/host/opentitantool/BUILD

diff --git a/sw/host/opentitantool/BUILD b/sw/host/opentitantool/BUILD
index 54d3392..19222cd 100644
--- a/sw/host/opentitantool/BUILD
+++ b/sw/host/opentitantool/BUILD
@@ -24,9 +24,15 @@
         "src/command/version.rs",
         "src/main.rs",
     ],
+    compile_data = [
+        "//util:full_version.txt",
+    ],
     proc_macro_deps = [
         "//sw/host/opentitanlib/opentitantool_derive",
     ],
+    rustc_env = {
+        "VERSION_FILE": "$(location //util:full_version.txt)",
+    },
     stamp = 1,
     deps = [
         "//sw/host/opentitanlib",

sw/host/opentitantool/src/command/version.rs

diff --git a/sw/host/opentitantool/src/command/version.rs b/sw/host/opentitantool/src/command/version.rs
index 80b007f..375e52e 100644
--- a/sw/host/opentitantool/src/command/version.rs
+++ b/sw/host/opentitantool/src/command/version.rs
@@ -19,17 +19,15 @@
 ///
 /// At runtime, this string is parsed into key/value pairs, which are returned.  (It would have
 /// been desirable to perform the parsing at compile time as well.)
-/// TODO(ykwang): The include path has to be prefixed with "../../" when setup opentitan as
-/// external repo.
-///fn get_volatile_status() -> BTreeMap<&'static str, &'static str> {
-///    let volatile_status = include_str!("../../../../../bazel-out/volatile-status.txt");
-///    let re = Regex::new(r"([A-Z_]+) ([^\n]+)\n").unwrap();
-///    let mut properties: BTreeMap<&'static str, &'static str> = BTreeMap::new();
-///    for cap in re.captures_iter(volatile_status) {
-///        properties.insert(cap.get(1).unwrap().as_str(), cap.get(2).unwrap().as_str());
-///    }
-///    properties
-///}
+fn get_volatile_status() -> BTreeMap<&'static str, &'static str> {
+    let volatile_status = include_str!(env!("VERSION_FILE"));
+    let re = Regex::new(r"([A-Z_]+) ([^\n]+)\n").unwrap();
+    let mut properties: BTreeMap<&'static str, &'static str> = BTreeMap::new();
+    for cap in re.captures_iter(volatile_status) {
+        properties.insert(cap.get(1).unwrap().as_str(), cap.get(2).unwrap().as_str());
+    }
+    properties
+}
 
 #[derive(Debug, StructOpt)]
 pub struct Version {}
@@ -40,8 +38,6 @@
     clean: bool,
     timestamp: i64,
 }
-#[derive(Debug, serde::Serialize)]
-pub struct DummyResponse {}
 
 impl CommandDispatch for Version {
     fn run(
@@ -49,13 +45,12 @@
         _context: &dyn Any,
         _transport: &TransportWrapper,
     ) -> Result<Option<Box<dyn Serialize>>> {
-        //let properties = get_volatile_status();
-        //Ok(Some(Box::new(VersionResponse {
-        //    version: properties.get("BUILD_GIT_VERSION").unwrap().to_string(),
-        //    revision: properties.get("BUILD_SCM_REVISION").unwrap().to_string(),
-        //    clean: *properties.get("BUILD_SCM_STATUS").unwrap() == "clean",
-        //    timestamp: properties.get("BUILD_TIMESTAMP").unwrap().parse::<i64>()?,
-        //})))
-        Ok(Some(Box::new(DummyResponse {})))
+        let properties = get_volatile_status();
+        Ok(Some(Box::new(VersionResponse {
+            version: properties.get("BUILD_GIT_VERSION").unwrap().to_string(),
+            revision: properties.get("BUILD_SCM_REVISION").unwrap().to_string(),
+            clean: *properties.get("BUILD_SCM_STATUS").unwrap() == "clean",
+            timestamp: properties.get("BUILD_TIMESTAMP").unwrap().parse::<i64>()?,
+        })))
     }
 }

util/BUILD

diff --git a/util/BUILD b/util/BUILD
index 7d3c2b8..932a1a5 100644
--- a/util/BUILD
+++ b/util/BUILD
@@ -19,7 +19,7 @@
 genrule(
     name = "full_version_file",
     outs = ["full_version.txt"],
-    cmd = """cp bazel-out/volatile-status.txt $@""",
+    cmd = """cp -f bazel-out/volatile-status.txt $@""",
     stamp = 1,  # this provides volatile-status.txt
 )