Refactor pwndbg.proc.exe and pwndbg.proc.get_file

Revert the change from 3e4ad60 and make the `pwndbg.proc.get_file` to strip the "target:" prefix instead of the `pwndbg.proc.exe`.

This way, we will prevent bugs when pwndbg code would use `pwndbg.proc.exe` on remote targets but not pass the returned path to `pwndbg.proc.get_file` to get the real remote file and instead use the local one (if it exists in the same path).

Additionally, we assert the `path` passed to `pwndbg.proc.get_file` so we prevent incorrect use of the function when an absolute path or not a remote path is passed to it.

pwndbg/file.py

@@ -22,13 +22,23 @@ def get_file(path):
     Downloads the specified file from the system where the current process is
     being debugged.
 
+    If the `path` is prefixed with "target:" the prefix is stripped
+    (to support remote target paths properly).
+
     Returns:
         The local path to the file
     """
+    assert path.startswith('/') or path.startswith('target:'), "get_file called with incorrect path"
+
+    if path.startswith('target:'):
+        path = path[7:]  # len('target:') == 7
+
     local_path = path
     qemu_root = pwndbg.qemu.root()
+
     if qemu_root:
         return os.path.join(qemu_root, path)
+
     elif pwndbg.remote.is_remote():
         if not pwndbg.qemu.is_qemu():
             local_path = tempfile.mktemp(dir=pwndbg.symbol.remote_files_dir)

pwndbg/proc.py

@@ -59,21 +59,17 @@ class module(ModuleType):
     @property
     def exe(self):
         """
-        We lstrip "target:" for remote debugging. Otherwise, the
+        Returns the debugged file name.
-        `pwndbg.file.get_file(pwndbg.proc.exe)` would not work on remote targets.
 
-        This should not be a problem on local targets as `gdb.current_progspace().filename`
+        On remote targets, this may be prefixed with "target:" string.
-        seems to return absolute paths.
+        See this by executing those in two terminals:
+        1. gdbserver 127.0.0.1:1234 /bin/ls
+        2. gdb -ex "target remote :1234" -ex "pi pwndbg.proc.exe"
 
-        DO NOT USE THIS if you want to process the debugged file with another tool.
+        If you need to process the debugged file use:
-        For this, use `pwndbg.file.get_file` as it supports remote target.
+            `pwndbg.file.get_file(pwndbg.proc.exe)`
         """
-        fn = gdb.current_progspace().filename
+        return gdb.current_progspace().filename
-
-        if fn.startswith('target:'):
-            return fn[7:]  # len('target') == 7
-
-        return fn
 
     @property
     def mem_page(self):