1 files changed, 65 insertions, 29 deletions

diff --git a/arch/um/os-Linux/file.c b/arch/um/os-Linux/file.c
index fc4450db59bd..5adf8f630049 100644
--- a/arch/um/os-Linux/file.c
+++ b/arch/um/os-Linux/file.c
@@ -17,6 +17,7 @@
 #include <sys/stat.h>
 #include <sys/sysmacros.h>
 #include <sys/un.h>
+#include <sys/mman.h>
 #include <sys/types.h>
 #include <sys/eventfd.h>
 #include <poll.h>
@@ -240,6 +241,16 @@ out:
 	return err;
 }
 
+int os_dup_file(int fd)
+{
+	int new_fd = dup(fd);
+
+	if (new_fd < 0)
+		return -errno;
+
+	return new_fd;
+}
+
 void os_close_file(int fd)
 {
 	close(fd);
@@ -502,44 +513,47 @@ int os_shutdown_socket(int fd, int r, int w)
 	return 0;
 }
 
-int os_rcv_fd(int fd, int *helper_pid_out)
+/**
+ * os_rcv_fd_msg - receive message with (optional) FDs
+ * @fd: the FD to receive from
+ * @fds: the array for FDs to write to
+ * @n_fds: number of FDs to receive (@fds array size)
+ * @data: the message buffer
+ * @data_len: the size of the message to receive
+ *
+ * Receive a message with FDs.
+ *
+ * Returns: the size of the received message, or an error code
+ */
+ssize_t os_rcv_fd_msg(int fd, int *fds, unsigned int n_fds,
+		      void *data, size_t data_len)
 {
-	int new, n;
-	char buf[CMSG_SPACE(sizeof(new))];
-	struct msghdr msg;
+	char buf[CMSG_SPACE(sizeof(*fds) * n_fds)];
 	struct cmsghdr *cmsg;
-	struct iovec iov;
-
-	msg.msg_name = NULL;
-	msg.msg_namelen = 0;
-	iov = ((struct iovec) { .iov_base  = helper_pid_out,
-				.iov_len   = sizeof(*helper_pid_out) });
-	msg.msg_iov = &iov;
-	msg.msg_iovlen = 1;
-	msg.msg_control = buf;
-	msg.msg_controllen = sizeof(buf);
-	msg.msg_flags = 0;
+	struct iovec iov = {
+		.iov_base = data,
+		.iov_len = data_len,
+	};
+	struct msghdr msg = {
+		.msg_iov = &iov,
+		.msg_iovlen = 1,
+		.msg_control = buf,
+		.msg_controllen = sizeof(buf),
+	};
+	int n;
 
 	n = recvmsg(fd, &msg, 0);
 	if (n < 0)
 		return -errno;
-	else if (n != iov.iov_len)
-		*helper_pid_out = -1;
 
 	cmsg = CMSG_FIRSTHDR(&msg);
-	if (cmsg == NULL) {
-		printk(UM_KERN_ERR "rcv_fd didn't receive anything, "
-		       "error = %d\n", errno);
-		return -1;
-	}
-	if ((cmsg->cmsg_level != SOL_SOCKET) ||
-	    (cmsg->cmsg_type != SCM_RIGHTS)) {
-		printk(UM_KERN_ERR "rcv_fd didn't receive a descriptor\n");
-		return -1;
-	}
+	if (!cmsg ||
+	    cmsg->cmsg_level != SOL_SOCKET ||
+	    cmsg->cmsg_type != SCM_RIGHTS)
+		return n;
 
-	new = ((int *) CMSG_DATA(cmsg))[0];
-	return new;
+	memcpy(fds, CMSG_DATA(cmsg), cmsg->cmsg_len);
+	return n;
 }
 
 int os_create_unix_socket(const char *file, int len, int close_on_exec)
@@ -705,3 +719,25 @@ int os_poll(unsigned int n, const int *fds)
 
 	return -EIO;
 }
+
+void *os_mmap_rw_shared(int fd, size_t size)
+{
+	void *res = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+
+	if (res == MAP_FAILED)
+		return NULL;
+
+	return res;
+}
+
+void *os_mremap_rw_shared(void *old_addr, size_t old_size, size_t new_size)
+{
+	void *res;
+
+	res = mremap(old_addr, old_size, new_size, MREMAP_MAYMOVE, NULL);
+
+	if (res == MAP_FAILED)
+		return NULL;
+
+	return res;
+}