Mirror of the gdb-patches mailing list
 help / color / mirror / Atom feed
From: Hannes Domani <ssbssa@yahoo.de>
To: gdb-patches@sourceware.org
Subject: [PATCH] Fix DLL export forwarding
Date: Mon,  4 Dec 2023 17:50:29 +0100	[thread overview]
Message-ID: <20231204165029.408-1-ssbssa@yahoo.de> (raw)
In-Reply-To: <20231204165029.408-1-ssbssa.ref@yahoo.de>

I noticed it when I was trying to set a breakpoint at ExitProcess:
```
(gdb) b ExitProcess
Breakpoint 1 at 0x14001fdd0
(gdb) r
Starting program: C:\qiewer\heob\heob64.exe
Warning:
Cannot insert breakpoint 1.
Cannot access memory at address 0x3dbf4120
Cannot insert breakpoint 1.
Cannot access memory at address 0x77644120
```

The problem doesn't exist in gdb 13.2, and the difference can easily be
seen when printing ExitProcess.
gdb 14.1:
```
(gdb) p ExitProcess
$1 = {<text variable, no debug info>} 0x77644120 <UserHandleGrantAccess+36128>
```
gdb 13.2:
```
(gdb) p ExitProcess
$1 = {<text variable, no debug info>} 0x77734120 <ntdll!RtlExitUserProcess>
```

The new behavior started with 9675da25357c7a3f472731ddc6eb3becc65b469a,
where VMA was then calculated relative to FORWARD_DLL_NAME, while it was
relative to DLL_NAME before.

Fixed by calculating VMA relative to DLL_NAME again.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31112
---
 gdb/coff-pe-read.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/gdb/coff-pe-read.c b/gdb/coff-pe-read.c
index 56137ac4dd0..c9d6d86a085 100644
--- a/gdb/coff-pe-read.c
+++ b/gdb/coff-pe-read.c
@@ -210,7 +210,10 @@ add_pe_forwarded_sym (minimal_symbol_reader &reader,
 			      " \"%s\" in dll \"%s\", pointing to \"%s\"\n"),
 		sym_name, dll_name, forward_qualified_name.c_str ());
 
-  unrelocated_addr vma = msymbol.minsym->unrelocated_address ();
+  /* Calculate VMA as if if where relative to DLL_NAME/OBJFILE, even though
+     it actually points inside another dll (FORWARD_DLL_NAME).  */
+  unrelocated_addr vma = unrelocated_addr(msymbol.value_address ()
+					  - objfile->text_section_offset ());
   msymtype = msymbol.minsym->type ();
   section = msymbol.minsym->section_index ();
 
-- 
2.35.1


       reply	other threads:[~2023-12-04 16:50 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20231204165029.408-1-ssbssa.ref@yahoo.de>
2023-12-04 16:50 ` Hannes Domani [this message]
2023-12-04 17:34   ` Lancelot SIX
2023-12-06 19:31   ` Tom Tromey
2023-12-06 20:16     ` Hannes Domani

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20231204165029.408-1-ssbssa@yahoo.de \
    --to=ssbssa@yahoo.de \
    --cc=gdb-patches@sourceware.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox