1 files changed, 145 insertions, 0 deletions
diff --git a/util/statetrace/tracechild.cc b/util/statetrace/tracechild.cc
new file mode 100644
index 000000000..292c45658
--- /dev/null
+++ b/util/statetrace/tracechild.cc
@@ -0,0 +1,145 @@
+/*
+ * Copyright (c) 2006 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 <sys/wait.h>
+#include <sys/ptrace.h>
+#include <iostream>
+#include <errno.h>
+
+using namespace std;
+
+bool TraceChild::startTracing(const char * pathToFile, const char * arg)
+{
+        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
+                ptrace(PTRACE_TRACEME, 0, 0, 0);
+
+                //Start the program to trace
+                execl(pathToFile, arg);
+
+                //We should never get here, so this is an error!
+                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;
+        if(!update(pid))
+        {
+                cout << "Didn't update successfully!" << endl;
+                return false;
+        }
+        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;
+                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;
+                return false;
+        }
+        if(WIFSTOPPED(wait_val) && WSTOPSIG(wait_val) != SIGTRAP)
+        {
+                cerr << "Program stopped by signal "
+                        << WSTOPSIG(wait_val) << endl;
+                tracing = false;
+                return false;
+        }
+        return true;
+}