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authorJohannes Berg <johannes.berg@intel.com>2020-02-13 16:26:47 +0300
committerRichard Weinberger <richard@nod.at>2020-03-30 00:29:08 +0300
commit88ce642492339f49a0b391af40e5798c08948e49 (patch)
tree157046746a6ff7554cc0b843daad22519ad88e74 /arch/um/os-Linux
parentdd9ada5627245a3441ebde00736dd63d09acc222 (diff)
downloadlinux-88ce642492339f49a0b391af40e5798c08948e49.tar.xz
um: Implement time-travel=ext
This implements synchronized time-travel mode which - using a special application on a unix socket - lets multiple machines take part in a time-travelling simulation together. The protocol for the unix domain socket is defined in the new file include/uapi/linux/um_timetravel.h. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'arch/um/os-Linux')
-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;
+}