Updated ptrace wrapper to allow creation of new processes.

3 files changed, 54 insertions, 8 deletions

diff --git a/hypodermic/ptrace.py b/hypodermic/ptrace.py
index fdfe5b8..d073930 100644
--- a/hypodermic/ptrace.py
+++ b/hypodermic/ptrace.py
@@ -29,29 +29,42 @@ class Process(object):
         object.
 
     Args:
-        pid (int): The pid of the process to attach to.
+        pid (:obj:`int`, optional): The pid of the process to attach to.
+            Defaults to 0, which means that it will not be used.
+        path (:obj:`str`, optional): The path of the binary to run.
+            Defaults to "", which will be used if no pid is specified.
 
     Raises:
         TypeError: If the pid argument is not an int.
         OSError: If the pid cannot be attached to.
     """
 
-    def __init__(self, pid: int):
+    def __init__(self, pid=0, path=""):
         if not isinstance(pid, int):
             raise TypeError("pid argument must be an int")
+        elif not isinstance(path, str):
+            raise TypeError("path argument must be a string")
         self._load_ffi_methods()
 
-        if self._attach(ctypes.c_int(pid)):
-            raise OSError("Could not attach to pid {}".format(pid))
-        self.pid = pid
+        if pid != 0:
+            self._is_parent = False
+            if self._attach(ctypes.c_int(pid)):
+                raise OSError("Could not attach to pid {}".format(pid))
+        else:
+            self._is_parent = True
+            self.pid = self._new_proc(ctypes.c_char_p(path.encode()))
+            if self.pid < 0:
+                raise OSError("Could not create process {}".format(path))
+
 
     def __del__(self):
-        if hasattr(self, "pid"):
+        if hasattr(self, "_is_parent") and not self._is_parent:
             self.detach()
 
     def _load_ffi_methods(self):
         # FIXME: How are we going to deal with the path?
         self._so = ctypes.cdll.LoadLibrary("/tmp/libptracew.so")
+        self._new_proc = self._so.new_proc
         self._attach = self._so.attach
         self._detach = self._so.detach
         self._cont = self._so.cont
@@ -62,7 +75,7 @@ class Process(object):
         Raises:
             OSError: If the process cannot be detached from.
         """
-        if self._detach(ctypes.c_int(self.pid)):
+        if not self._is_parent and self._detach(ctypes.c_int(self.pid)):
             raise OSError("Could not detach from pid {}".format(self.pid))
 
     def cont(self):
diff --git a/wrapper/Makefile b/wrapper/Makefile
index 1019833..026f4ba 100644
--- a/wrapper/Makefile
+++ b/wrapper/Makefile
@@ -8,5 +8,5 @@ LDFLAGS += $(USER_LDFLAGS)
 
 all: libptracew.so
 
-libtestw.so: ptrace.c
+libptracew.so: ptrace.c
 	$(CC) $(CFLAGS) $^ -o $@ $(LDFLAGS)
diff --git a/wrapper/ptrace.c b/wrapper/ptrace.c
index 3ce42a1..caf510f 100644
--- a/wrapper/ptrace.c
+++ b/wrapper/ptrace.c
@@ -16,9 +16,42 @@
    along with Hypodermic. If not, see <http://www.gnu.org/licenses/>. */
 
 #include <sys/ptrace.h>
+#include <sys/types.h>
 #include <sys/wait.h>
 
 #include <stddef.h>
+#include <unistd.h>
+
+
+static void run_target(const char *path) {
+    if (ptrace(PTRACE_TRACEME, 0, NULL, NULL) < 0) {
+        return;
+    }
+
+    execl(path, path, 0);
+}
+
+
+int new_proc(const char *path) {
+    int   wait_stat;
+    pid_t pid;
+
+    if (path == NULL) {
+        return -1;
+    }
+
+    pid = fork();
+
+    if (pid == 0) {
+        run_target(path);
+    } else if (pid > 0) {
+        wait(&wait_stat);
+    } else {
+        return -1;
+    }
+
+    return pid;
+}
 
 
 int attach(int pid) {