From ef53352dbc0a149f6bc6eab555887ac646914144 Mon Sep 17 00:00:00 2001
From: Ahmad Samir <a.samirh78@gmail.com>
Date: Mon, 29 May 2023 21:54:22 +0300
Subject: [PATCH] QFileDialog: use ::sysconf() to get initial passwd struct
 buffer size

Use QVLA since buf is no techincally a var-length-array.

Change-Id: I334cf2d1f9ef162495ed223a8e48e1b8e674afc0
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>
---
 src/widgets/dialogs/qfiledialog.cpp | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/widgets/dialogs/qfiledialog.cpp b/src/widgets/dialogs/qfiledialog.cpp
index 7461a643ad3..6b146bbaa56 100644
--- a/src/widgets/dialogs/qfiledialog.cpp
+++ b/src/widgets/dialogs/qfiledialog.cpp
@@ -1109,13 +1109,15 @@ static QString homeDirFromPasswdEntry(const QString &path, const QByteArray &use
 #if defined(_POSIX_THREAD_SAFE_FUNCTIONS) && !defined(Q_OS_OPENBSD) && !defined(Q_OS_WASM)
     passwd pw;
     passwd *tmpPw;
-    char buf[200];
-    const int bufSize = sizeof(buf);
+    long bufSize = ::sysconf(_SC_GETPW_R_SIZE_MAX);
+    if (bufSize == -1)
+        bufSize = 1024;
+    QVarLengthArray<char, 1024> buf(bufSize);
     int err = 0;
 #  if defined(Q_OS_SOLARIS) && (_POSIX_C_SOURCE - 0 < 199506L)
-    tmpPw = getpwnam_r(userName.constData(), &pw, buf, bufSize);
+    tmpPw = getpwnam_r(userName.constData(), &pw, buf.data(), buf.size());
 #  else
-    err = getpwnam_r(userName.constData(), &pw, buf, bufSize, &tmpPw);
+    err = getpwnam_r(userName.constData(), &pw, buf.data(), buf.size(), &tmpPw);
 #  endif
     if (err || !tmpPw)
         return path;