From: Josh Kunz via Qemu-devel <qemu-devel@nongnu.org>
To: qemu-devel@nongnu.org
Cc: qemu-trivial@nongnu.org, riku.voipio@iki.f, laurent@vivier.eu,
Josh Kunz <jkz@google.com>
Subject: [Qemu-devel] [PATCH] linux-user: Support gdb 'qOffsets' query for ELF
Date: Fri, 16 Aug 2019 16:34:22 -0700 [thread overview]
Message-ID: <20190816233422.16715-1-jkz@google.com> (raw)
This is needed to support debugging PIE ELF binaries running under QEMU
user mode. Currently, `code_offset` and `data_offset` remain unset for
all ELF binaries, so GDB is unable to correctly locate the position of
the binary's text and data.
The fields `code_offset`, and `data_offset` were originally added way
back in 2006 to support debugging of bFMT executables (978efd6aac6),
and support was just never added for ELF. Since non-PIE binaries are
loaded at exactly the address specified in the binary, GDB does not need
to relocate any symbols, so the buggy behavior is not normally observed.
Buglink: https://bugs.launchpad.net/qemu/+bug/1528239
Signed-off-by: Josh Kunz <jkz@google.com>
---
linux-user/elfload.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 3365e192eb..ceac035208 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -2380,6 +2380,8 @@ static void load_elf_image(const char *image_name, int image_fd,
}
info->load_bias = load_bias;
+ info->code_offset = load_bias;
+ info->data_offset = load_bias;
info->load_addr = load_addr;
info->entry = ehdr->e_entry + load_bias;
info->start_code = -1;
--
2.23.0.rc1.153.gdeed80330f-goog
next reply other threads:[~2019-08-17 1:05 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-16 23:34 Josh Kunz via Qemu-devel [this message]
2019-08-16 23:36 ` [Qemu-devel] [PATCH] linux-user: Support gdb 'qOffsets' query for ELF Josh Kunz via Qemu-devel
2019-08-17 1:35 ` no-reply
2019-08-26 8:29 ` Laurent Vivier
2019-09-03 19:19 ` Josh Kunz via Qemu-devel
2019-09-04 5:23 ` Laurent Vivier
2019-09-05 10:54 ` Philippe Mathieu-Daudé
2019-09-10 8:23 ` Laurent Vivier
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