path: root/util/oslib-win32.c
diff options
authorDaniel P. Berrange <>2015-08-28 14:40:01 +0100
committerDaniel P. Berrange <>2015-10-20 14:40:49 +0100
commit57cb38b3833c5215131b983f181b26d6ba9b8d35 (patch)
treee277f087c5a7c2f9a4240637936a80e2b09f89be /util/oslib-win32.c
parente0d03b8ceb52e390b8b0a5db1762a8435dd8a44e (diff)
osdep: add qemu_fork() wrapper for safely handling signals
When using regular fork() the child process of course inherits all the parents' signal handlers. If the child then proceeds to close() any open file descriptors, it may break some of those registered signal handlers. The child generally does not want to ever run any of the signal handlers that the parent may have installed in the short time before it exec's. The parent may also have blocked various signals which the child process will want enabled. This introduces a wrapper qemu_fork() that takes care to sanitize signal handling across fork. Before forking it blocks all signals in the parent thread. After fork returns, the parent unblocks the signals and carries on as usual. The child, however, resets all the signal handlers back to their defaults before it unblocks signals. The child process can now exec the binary in a "clean" signal environment. Signed-off-by: Daniel P. Berrange <>
Diffstat (limited to 'util/oslib-win32.c')
1 files changed, 9 insertions, 0 deletions
diff --git a/util/oslib-win32.c b/util/oslib-win32.c
index 08f5a9c..09f9e98 100644
--- a/util/oslib-win32.c
+++ b/util/oslib-win32.c
@@ -496,3 +496,12 @@ int qemu_read_password(char *buf, int buf_size)
buf[i] = '\0';
return 0;
+pid_t qemu_fork(Error **errp)
+ errno = ENOSYS;
+ error_setg_errno(errp, errno,
+ "cannot fork child process");
+ return -1;
OpenPOWER on IntegriCloud