1 files changed, 147 insertions, 0 deletions
diff --git a/util/statetrace/base/tracechild.cc b/util/statetrace/base/tracechild.cc
new file mode 100644
index 000000000..b5665ff37
--- /dev/null
+++ b/util/statetrace/base/tracechild.cc
@@ -0,0 +1,147 @@
+/*
+ * Copyright (c) 2006-2007 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Gabe Black
+ */
+
+#include "tracechild.hh"
+#include <cstring>
+#include <errno.h>
+#include <iostream>
+#include <sys/ptrace.h>
+#include <sys/wait.h>
+
+using namespace std;
+
+bool
+TraceChild::startTracing(const char * pathToFile, char * const argv[])
+{
+    instructions = 0;
+    pid = fork();
+    if (pid == -1) {
+        cout << "fork failed" << endl;
+        return false;
+    } else if (pid == 0) {
+        //We're the child. Get things ready and then exec the program to trace.
+        //Let our parent trace us
+        if (ptrace(PTRACE_TRACEME, 0, 0, 0) == -1) {
+            cout << "Failure calling TRACEME\n" << strerror(errno) << endl;
+            return false;
+        }
+
+        //Set up an empty environment for the child... We would want to
+        //specify this somehow at some point
+        char * env[] = {NULL};
+
+        //Start the program to trace
+        execve(pathToFile, argv, env);
+
+        //We should never get here, so this is an error!
+        cout << "Exec failed\n" <<  strerror(errno) << endl;
+        return false;
+    }
+
+    //From this point forward, we know we're in the parent process.
+    if (!doWait()) {
+        cout << "Didn't wait successfully" << endl;
+        return false;
+    }
+    tracing = true;
+    return true;
+}
+
+bool
+TraceChild::stopTracing()
+{
+    if (ptrace(PTRACE_KILL, pid, 0, 0) != 0)
+        return false;
+    tracing = false;
+    return true;
+}
+
+bool
+TraceChild::step()
+{
+    ptraceSingleStep();
+}
+
+bool
+TraceChild::ptraceSingleStep()
+{
+    if (!tracing) {
+        cout << "Not tracing!" << endl;
+        return false;
+    }
+    if (ptrace(PTRACE_SINGLESTEP, pid, 0, 0) != 0) {
+        switch (errno) {
+          case EBUSY: cout << "EBUSY" << endl; break;
+          case EFAULT: cout << "EFAULT" << endl; break;
+          case EIO: cout << "EIO" << endl; break;
+          case EPERM: cout << "EPERM" << endl; break;
+          case ESRCH: cout << "ESRCH" << endl; break;
+          default: cout << "Unknown error" << endl; break;
+        }
+        cout << "Not able to single step!" << endl;
+        tracing == false;
+        return false;
+    }
+    doWait();
+    update(pid);
+}
+
+bool
+TraceChild::doWait()
+{
+    int wait_val;
+    wait(&wait_val);
+    if (WIFEXITED(wait_val)) {
+        cerr << "Program exited! Exit status is "
+             << WEXITSTATUS(wait_val) << endl;
+        cerr << "Executed " << instructions
+             << " instructions." << endl;
+        tracing = false;
+        return false;
+    }
+    if (WIFSIGNALED(wait_val)) {
+        if (WTERMSIG(wait_val))
+            cerr << "Program terminated by signal "
+                 << WTERMSIG(wait_val) << endl;
+        if (WCOREDUMP(wait_val))
+            cerr << "Program core dumped!" << endl;
+        tracing = false;
+        cerr << "Executed " << instructions
+             << " instructions." << endl;
+        return false;
+    }
+    if (WIFSTOPPED(wait_val) && WSTOPSIG(wait_val) != SIGTRAP) {
+        cerr << "Program stopped by signal " << WSTOPSIG(wait_val) << endl;
+        tracing = false;
+        cerr << "Executed " << instructions << " instructions." << endl;
+            return false;
+    }
+    return true;
+}