[PATCH v4 05/15] qga: add qga_open_cloexec() helper

[marcandre.lureau@redhat.com]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

QGA calls qemu_open_old() in various places. Calling qemu_open() instead
isn't a great alternative, as it has special "/dev/fdset" handling and
depends on QEMU internal monitor data structures.

Instead, provide a simple helper for QGA needs, with Error* support. The
following patches will make use of it.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 qga/cutils.c    | 37 +++++++++++++++++++++++++++++++++++++
 qga/cutils.h    |  8 ++++++++
 qga/meson.build |  1 +
 3 files changed, 46 insertions(+)
 create mode 100644 qga/cutils.c
 create mode 100644 qga/cutils.h

diff --git a/qga/cutils.c b/qga/cutils.c
new file mode 100644
index 0000000000..37dd877451
--- /dev/null
+++ b/qga/cutils.c
@@ -0,0 +1,37 @@
+/*
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+#include "cutils.h"
+
+#include "qapi/error.h"
+
+/**
+ * qga_open_cloexec:
+ * @name: the pathname to open
+ * @flags: as in open()
+ * @mode: as in open()
+ * @errp: pointer to Error*, or NULL
+ *
+ * A wrapper for open() function which sets O_CLOEXEC.
+ *
+ * On error, -1 is returned and @errp is set.
+ */
+int qga_open_cloexec(const char *name, int flags, mode_t mode, Error **errp)
+{
+    int ret;
+
+#ifdef O_CLOEXEC
+    ret = open(name, flags | O_CLOEXEC, mode);
+#else
+    ret = open(name, flags, mode);
+    if (ret >= 0) {
+        qemu_set_cloexec(ret);
+    }
+#endif
+    if (ret == -1) {
+        error_setg_errno(errp, errno, "Failed to open file '%s'", name);
+    }
+
+    return ret;
+}
diff --git a/qga/cutils.h b/qga/cutils.h
new file mode 100644
index 0000000000..caccf79e45
--- /dev/null
+++ b/qga/cutils.h
@@ -0,0 +1,8 @@
+#ifndef CUTILS_H_
+#define CUTILS_H_
+
+#include "qemu/osdep.h"
+
+int qga_open_cloexec(const char *name, int flags, mode_t mode, Error **errp);
+
+#endif /* CUTILS_H_ */
diff --git a/qga/meson.build b/qga/meson.build
index 6d9f39bb32..35fe2229e9 100644
--- a/qga/meson.build
+++ b/qga/meson.build
@@ -65,6 +65,7 @@ qga_ss.add(files(
   'commands.c',
   'guest-agent-command-state.c',
   'main.c',
+  'cutils.c',
 ))
 qga_ss.add(when: 'CONFIG_POSIX', if_true: files(
   'channel-posix.c',
-- 
2.36.1