[V2,07/11] oslib: qemu_clear_cloexec

Commit Message

Steve Sistare June 30, 2024, 7:40 p.m. UTC

Define qemu_clear_cloexec, analogous to qemu_set_cloexec.

Signed-off-by: Steve Sistare <[e-mail]>
Reviewed-by: Dr. David Alan Gilbert <[e-mail]>
Reviewed-by: Marc-André Lureau <[e-mail]>
Reviewed-by: Fabiano Rosas <[e-mail]>
---
 include/qemu/osdep.h | 9 +++++++++
 util/oslib-posix.c   | 9 +++++++++
 util/oslib-win32.c   | 4 ++++
 3 files changed, 22 insertions(+)

Patch

diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index 191916f..6ebf192 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -662,6 +662,15 @@  ssize_t qemu_write_full(int fd, const void *buf, size_t count)
 
 void qemu_set_cloexec(int fd);
 
+/*
+ * Clear FD_CLOEXEC for a descriptor.
+ *
+ * The caller must guarantee that no other fork+exec's occur before the
+ * exec that is intended to inherit this descriptor, eg by suspending CPUs
+ * and blocking monitor commands.
+ */
+void qemu_clear_cloexec(int fd);
+
 /* Return a dynamically allocated directory path that is appropriate for storing
  * local state.
  *
diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index e764416..614c3e5 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -272,6 +272,15 @@  int qemu_socketpair(int domain, int type, int protocol, int sv[2])
     return ret;
 }
 
+void qemu_clear_cloexec(int fd)
+{
+    int f;
+    f = fcntl(fd, F_GETFD);
+    assert(f != -1);
+    f = fcntl(fd, F_SETFD, f & ~FD_CLOEXEC);
+    assert(f != -1);
+}
+
 char *
 qemu_get_local_state_dir(void)
 {
diff --git a/util/oslib-win32.c b/util/oslib-win32.c
index b623830..c3e969a 100644
--- a/util/oslib-win32.c
+++ b/util/oslib-win32.c
@@ -222,6 +222,10 @@  void qemu_set_cloexec(int fd)
 {
 }
 
+void qemu_clear_cloexec(int fd)
+{
+}
+
 int qemu_get_thread_id(void)
 {
     return GetCurrentThreadId();