From bfdb52f83ca6ca3a0eb43ef2bd0f4f8193a06472 Mon Sep 17 00:00:00 2001 From: Tom Tromey Date: Tue, 19 Apr 2022 11:21:35 -0600 Subject: [PATCH] Handle encoding failures in Windows thread names Internally at AdaCore, we noticed that the new Windows thread name code could fail. First, it might return a zero-length string, but in gdb conventions it should return nullptr instead. Second, an encoding failure could wind up showing replacement characters to the user; this is confusing and not useful; it's better to recognize such errors and simply discard the name. This patch makes both of these changes. --- gdb/nat/windows-nat.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) diff --git a/gdb/nat/windows-nat.c b/gdb/nat/windows-nat.c index bd1b9459145..c8db19439f3 100644 --- a/gdb/nat/windows-nat.c +++ b/gdb/nat/windows-nat.c @@ -119,12 +119,23 @@ windows_thread_info::thread_name () HRESULT result = GetThreadDescription (h, &value); if (SUCCEEDED (result)) { - size_t needed = wcstombs (nullptr, value, 0); - if (needed != (size_t) -1) + int needed = WideCharToMultiByte (CP_ACP, 0, value, -1, nullptr, 0, + nullptr, nullptr); + if (needed != 0) { - name.reset ((char *) xmalloc (needed)); - if (wcstombs (name.get (), value, needed) == (size_t) -1) - name.reset (); + /* USED_DEFAULT is how we detect that the encoding + conversion had to fall back to the substitution + character. It seems better to just reject bad + conversions here. */ + BOOL used_default = FALSE; + gdb::unique_xmalloc_ptr new_name + ((char *) xmalloc (needed)); + if (WideCharToMultiByte (CP_ACP, 0, value, -1, + new_name.get (), needed, + nullptr, &used_default) == needed + && !used_default + && strlen (new_name.get ()) > 0) + name = std::move (new_name); } LocalFree (value); } -- 2.30.2