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symbol.py: remove _add_main_symbol_to_exe (#1609) 

It seems this function is redundant. If you do:

```
gdbserver 0.0.0.0:1234 ./a.out
```

on a local machine and then do `gdb ./a.out --ex 'target remote :1234'`
the `_add_main_symbol_to_exe` will kick off and run its
`add-symbol-file` command to add the symbols from the binary. However,
the GDB already loaded the binary symbols and so we will do it for the
second time. As a result, we get something like this:

```
pwndbg> info symbol main
main in section .text of /pwndbg/bug/vaccine
main in section .text of /pwndbg/bug/vaccine
```

This function has been in Pwndbg since always and I am not sure why we
needed it. Perhaps an old GDB did not download the binary from the
remote target, but since now GDB does this automagically, this function
seems redundant.

Just for the sake of documenting it, here is how a symbol appears if you
connect to a remote target on a different machine without Pwndbg (the
GDB downloads the binary itself and loads its symbols):

```
(gdb) p main
$1 = {<text variable, no debug info>} 0x55555555466a <main>
(gdb) info symbol main
main in section .text of target:/home/dc/a.out
```
This commit is contained in:
Disconnect3d 2023-03-06 06:28:57 -04:00 committed by GitHub
parent ffad9be01e
commit 9ac6e679e5
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1 changed files with 0 additions and 33 deletions
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33
pwndbg/gdblib/symbol.py
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@ -179,39 +179,6 @@ def static_linkage_symbol_address(symbol: str) -> int:
return None
@pwndbg.gdblib.events.stop
@pwndbg.lib.memoize.reset_on_start
def _add_main_exe_to_symbols() -> None:
if not pwndbg.gdblib.remote.is_remote():
return
if pwndbg.gdblib.android.is_android():
return
exe = pwndbg.gdblib.elf.exe()
if not exe:
return
addr = exe.address
if not addr:
return
addr = int(addr)
mmap = pwndbg.gdblib.vmmap.find(addr)
if not mmap:
return
path = mmap.objfile
if path and (pwndbg.gdblib.arch.endian == pwndbg.gdblib.arch.native_endian):
try:
gdb.execute("add-symbol-file %s" % (path,), from_tty=False, to_string=True)
except gdb.error:
pass
@pwndbg.lib.memoize.reset_on_stop
@pwndbg.lib.memoize.reset_on_start
def selected_frame_source_absolute_filename():