DAOS-16585 tests: Fix NLT handling of __fxstat detection

Use strace to determine whether calls to __fxstat actually happen
when using a utility/command the IL is being tested on, and stop
treating it as an error to not see __fxstat when it's not used.

Signed-off-by: Nicholas Murphy <ncmurphy@google.com>
Required-githooks: true

ci/unit/required_packages.sh

@@ -30,6 +30,7 @@ pkgs="argobots                         \
       pmix                             \
       protobuf-c                       \
       spdk-devel                       \
+      strace                           \  
       valgrind-devel"
 
 # output with trailing newline suppressed

utils/node_local_test.py

@@ -1521,8 +1521,8 @@ def il_cmd(self, cmd, check_read=True, check_write=True, check_fstat=True):
         print(f'Logged il to {log_name}')
         print(ret)
 
-        if self.caching:
-            check_fstat = False
+        check_fstat = check_fstat and not self.caching and \
+            look_for_library_call(self.conf, cmd, '__fxstat')
 
         try:
             log_test(self.conf, log_name, check_read=check_read, check_write=check_write,
@@ -6327,6 +6327,23 @@ def server_fi(args):
         server.set_fi(probability=0)
 
 
+def look_for_library_call(conf, cmd, library_str):
+    """Look for library_str in the strace call stack of running cmd."""
+    tmpfile = tempfile.NamedTemporaryFile(mode='r',
+                                          prefix='dnt_assess_',
+                                          suffix='.strace',
+                                          dir=conf.tmp_dir)
+    strace_cmd = ['strace', '--stack-traces', '-v', '-o', tmpfile.name] + cmd
+    subprocess.run(strace_cmd, check=True)
+    lines = tmpfile.readlines()
+    tmpfile.close()
+    for line in lines:
+        if re.search(library_str, line):
+            return True
+
+    return False
+
+
 def run(wf, args):
     """Main entry point"""
     # pylint: disable=too-many-branches

utils/scripts/install-el8.sh

@@ -60,6 +60,7 @@ dnf --nodocs install \
     python3-devel \
     python3-pip \
     sg3_utils \
+    strace \
     sudo \
     systemd \
     valgrind-devel \

utils/scripts/install-el9.sh

@@ -59,6 +59,7 @@ dnf --nodocs install \
     python3-devel \
     python3-pip \
     sg3_utils \
+    strace \
     sudo \
     valgrind-devel \
     which \

utils/scripts/install-leap15.sh

@@ -57,6 +57,7 @@ dnf --nodocs install \
     python3-devel \
     scons \
     sg3_utils \
+    strace \
     sudo \
     valgrind-devel \
     which \

utils/scripts/install-ubuntu.sh

@@ -52,6 +52,7 @@ apt-get install \
     pkg-config \
     python3-dev \
     python3-venv \
+    strace \
     uuid-dev \
     valgrind \
     yasm