gdblib/symbol.py: remove symbol autofetch (#1494)

Removing this _autofetch: first of all, it never called gdb.execute
since it was commented out. Second of all, GDB seems to do symbol
autofetching by default or at least with my simple tests it was working.

Maybe a very old GDB version did not do that and that's we wanted to
have it in the first place.

pwndbg/gdblib/symbol.py

@@ -5,14 +5,8 @@ vice-versa.
 Uses IDA when available if there isn't sufficient symbol
 information available.
 """
-import os
 import re
-from typing import Dict
 
-import elftools.common.exceptions
-import elftools.elf.constants
-import elftools.elf.elffile
-import elftools.elf.segments
 import gdb
 
 import pwndbg.gdblib.android
@@ -64,97 +58,6 @@ if "/usr/lib/debug" not in _get_debug_file_directory():
     _add_debug_file_directory("/usr/lib/debug")
 
 
-_remote_files: Dict[str, str] = {}
-
-
-@pwndbg.gdblib.events.exit
-def _reset_remote_files() -> None:
-    global _remote_files
-    _remote_files = {}
-
-
-@pwndbg.gdblib.events.new_objfile
-def _autofetch() -> None:
-    """
-    Automatically downloads ELF files with debug symbols from the remotely debugged system.
-    Does not work with QEMU and Android. It also does not work when debugging embedded devices, as they don't even have a filesystem.
-    """
-    if not pwndbg.gdblib.remote.is_remote():
-        return
-
-    if pwndbg.gdblib.remote.is_debug_probe():
-        return
-
-    if pwndbg.gdblib.qemu.is_qemu_usermode():
-        return
-
-    if pwndbg.gdblib.android.is_android():
-        return
-
-    remote_files_dir = pwndbg.gdblib.file.remote_files_dir()
-    if remote_files_dir not in _get_debug_file_directory().split(":"):
-        _add_debug_file_directory(remote_files_dir)
-
-    for mapping in pwndbg.gdblib.vmmap.get():
-        objfile = mapping.objfile
-
-        # Don't attempt to download things like '[stack]' and '[heap]'
-        if not objfile.startswith("/"):
-            continue
-
-        # Don't re-download things that we have already downloaded
-        if not objfile or objfile in _remote_files:
-            continue
-
-        msg = "Downloading %r from the remote server" % objfile
-        print(msg, end="")
-
-        try:
-            data = pwndbg.gdblib.file.get(objfile)
-            print("\r" + msg + ": OK")
-        except OSError:
-            # The file could not be downloaded :(
-            print("\r" + msg + ": Failed")
-            return
-
-        filename = os.path.basename(objfile)
-        local_path = os.path.join(remote_files_dir, filename)
-
-        with open(local_path, "wb+") as f:
-            f.write(data)
-
-        _remote_files[objfile] = local_path
-
-        base = None
-        for mapping in pwndbg.gdblib.vmmap.get():
-            if mapping.objfile != objfile:
-                continue
-
-            if base is None or mapping.vaddr < base.vaddr:
-                base = mapping
-
-        if not base:
-            continue
-
-        base = base.vaddr
-
-        try:
-            elf = elftools.elf.elffile.ELFFile(open(local_path, "rb"))
-        except elftools.common.exceptions.ELFError:
-            continue
-
-        gdb_command = ["add-symbol-file", local_path, hex(int(base))]
-        for section in elf.iter_sections():
-            name = section.name  # .decode('latin-1')
-            section = section.header
-            if not section.sh_flags & elftools.elf.constants.SH_FLAGS.SHF_ALLOC:
-                continue
-            gdb_command += ["-s", name, hex(int(base + section.sh_addr))]
-
-        print(" ".join(gdb_command))
-        # gdb.execute(' '.join(gdb_command), from_tty=False, to_string=True)
-
-
 @pwndbg.lib.memoize.reset_on_objfile
 def get(address: int, gdb_only=False) -> str:
     """