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-rw-r--r--arch/um/os-Linux/file.c30
1 files changed, 30 insertions, 0 deletions
diff --git a/arch/um/os-Linux/file.c b/arch/um/os-Linux/file.c
index 5c819f89b8c2..26ecbd64c409 100644
--- a/arch/um/os-Linux/file.c
+++ b/arch/um/os-Linux/file.c
@@ -5,6 +5,7 @@
#include <stdio.h>
#include <unistd.h>
+#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
@@ -17,6 +18,7 @@
#include <sys/un.h>
#include <sys/types.h>
#include <sys/eventfd.h>
+#include <poll.h>
#include <os.h>
static void copy_stat(struct uml_stat *dst, const struct stat64 *src)
@@ -665,3 +667,31 @@ int os_sendmsg_fds(int fd, const void *buf, unsigned int len, const int *fds,
return -errno;
return err;
}
+
+int os_poll(unsigned int n, const int *fds)
+{
+ /* currently need 2 FDs at most so avoid dynamic allocation */
+ struct pollfd pollfds[2] = {};
+ unsigned int i;
+ int ret;
+
+ if (n > ARRAY_SIZE(pollfds))
+ return -EINVAL;
+
+ for (i = 0; i < n; i++) {
+ pollfds[i].fd = fds[i];
+ pollfds[i].events = POLLIN;
+ }
+
+ ret = poll(pollfds, n, -1);
+ if (ret < 0)
+ return -errno;
+
+ /* Return the index of the available FD */
+ for (i = 0; i < n; i++) {
+ if (pollfds[i].revents)
+ return i;
+ }
+
+ return -EIO;
+}