From 80c152d6898c1b8727ac14d32437b274153a7089 Mon Sep 17 00:00:00 2001
From: Thiago Macieira <thiago.macieira@intel.com>
Date: Fri, 30 Jun 2017 13:30:52 -0700
Subject: Move the readlink(2) wrapper to qcore_unix.cpp
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This deduplicates the code between QFileSystemEngine and QLockFile.

Change-Id: I1eba2b016de74620bfc8fffd14cd005d5fd9beaa
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@qt.io>
---
 src/corelib/kernel/qcore_unix.cpp | 33 +++++++++++++++++++++++++++++++++
 src/corelib/kernel/qcore_unix_p.h |  2 ++
 2 files changed, 35 insertions(+)

(limited to 'src/corelib/kernel')

diff --git a/src/corelib/kernel/qcore_unix.cpp b/src/corelib/kernel/qcore_unix.cpp
index 686143f8c7..3b0da136ca 100644
--- a/src/corelib/kernel/qcore_unix.cpp
+++ b/src/corelib/kernel/qcore_unix.cpp
@@ -50,6 +50,37 @@
 
 QT_BEGIN_NAMESPACE
 
+QByteArray qt_readlink(const char *path)
+{
+#ifndef PATH_MAX
+    // suitably large value that won't consume too much memory
+#  define PATH_MAX  1024*1024
+#endif
+
+    QByteArray buf(256, Qt::Uninitialized);
+
+    ssize_t len = ::readlink(path, buf.data(), buf.size());
+    while (len == buf.size()) {
+        // readlink(2) will fill our buffer and not necessarily terminate with NUL;
+        if (buf.size() >= PATH_MAX) {
+            errno = ENAMETOOLONG;
+            return QByteArray();
+        }
+
+        // double the size and try again
+        buf.resize(buf.size() * 2);
+        len = ::readlink(path, buf.data(), buf.size());
+    }
+
+    if (len == -1)
+        return QByteArray();
+
+    buf.resize(len);
+    return buf;
+}
+
+#ifndef QT_BOOTSTRAPPED
+
 #if QT_CONFIG(poll_pollts)
 #  define ppoll pollts
 #endif
@@ -121,4 +152,6 @@ int qt_safe_poll(struct pollfd *fds, nfds_t nfds, const struct timespec *timeout
     }
 }
 
+#endif // QT_BOOTSTRAPPED
+
 QT_END_NAMESPACE
diff --git a/src/corelib/kernel/qcore_unix_p.h b/src/corelib/kernel/qcore_unix_p.h
index ea5d98cbf3..9d2c4f6c31 100644
--- a/src/corelib/kernel/qcore_unix_p.h
+++ b/src/corelib/kernel/qcore_unix_p.h
@@ -55,6 +55,7 @@
 #include <QtCore/private/qglobal_p.h>
 #include "qplatformdefs.h"
 #include "qatomic.h"
+#include "qbytearray.h"
 
 #ifndef Q_OS_UNIX
 # error "qcore_unix_p.h included on a non-Unix system"
@@ -339,6 +340,7 @@ static inline pid_t qt_safe_waitpid(pid_t pid, int *status, int options)
 // in qelapsedtimer_mac.cpp or qtimestamp_unix.cpp
 timespec qt_gettime() Q_DECL_NOTHROW;
 void qt_nanosleep(timespec amount);
+QByteArray qt_readlink(const char *path);
 
 /* non-static */
 inline bool qt_haveLinuxProcfs()
-- 
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