[V1,25/32] char: save/restore chardev pty fds

Commit Message

Steven Sistare July 30, 2020, 3:14 p.m. UTC

Save and restore pty descriptors across cprsave and cprload.

Signed-off-by: Steve Sistare <[e-mail]>
---
 chardev/char-pty.c     | 38 +++++++++++++++++++++++++++-----------
 chardev/char.c         |  2 ++
 include/chardev/char.h |  1 +
 3 files changed, 30 insertions(+), 11 deletions(-)

Patch

diff --git a/chardev/char-pty.c b/chardev/char-pty.c
index 1cc501a..0785429 100644
--- a/chardev/char-pty.c
+++ b/chardev/char-pty.c
@@ -30,6 +30,7 @@ 
 #include "qemu/sockets.h"
 #include "qemu/error-report.h"
 #include "qemu/module.h"
+#include "qemu/cutils.h"
 #include "qemu/qemu-print.h"
 
 #include "chardev/char-io.h"
@@ -183,6 +184,16 @@  static void pty_chr_state(Chardev *chr, int connected)
     }
 }
 
+void save_char_pty_fd(Chardev *chr)
+{
+    PtyChardev *s = PTY_CHARDEV(chr);
+    QIOChannelFile *fioc = QIO_CHANNEL_FILE(s->ioc);
+
+    if (fioc) {
+        setenv_fd(chr->label, fioc->fd);
+    }
+}
+
 static void char_pty_finalize(Object *obj)
 {
     Chardev *chr = CHARDEV(obj);
@@ -204,18 +215,23 @@  static void char_pty_open(Chardev *chr,
     char pty_name[PATH_MAX];
     char *name;
 
-    master_fd = qemu_openpty_raw(&slave_fd, pty_name);
-    if (master_fd < 0) {
-        error_setg_errno(errp, errno, "Failed to create PTY");
-        return;
-    }
-
-    close(slave_fd);
-    qemu_set_nonblock(master_fd);
+    master_fd = getenv_fd(chr->label);
+    if (master_fd >= 0) {
+        unsetenv_fd(chr->label);
+        chr->filename = g_strdup_printf("pty:unknown");
+    } else {
+        master_fd = qemu_openpty_raw(&slave_fd, pty_name);
+        if (master_fd < 0) {
+            error_setg_errno(errp, errno, "Failed to create PTY");
+            return;
+        }
 
-    chr->filename = g_strdup_printf("pty:%s", pty_name);
-    qemu_printf("char device redirected to %s (label %s)\n",
-                pty_name, chr->label);
+        close(slave_fd);
+        qemu_set_nonblock(master_fd);
+        chr->filename = g_strdup_printf("pty:%s", pty_name);
+        qemu_printf("char device redirected to %s (label %s)\n",
+                    pty_name, chr->label);
+    }
 
     s = PTY_CHARDEV(chr);
     s->ioc = QIO_CHANNEL(qio_channel_file_new_fd(master_fd));
diff --git a/chardev/char.c b/chardev/char.c
index 8fd54cc..da75a04 100644
--- a/chardev/char.c
+++ b/chardev/char.c
@@ -1180,6 +1180,8 @@  static int chardev_is_socket(Object *child, void *opaque)
 {
     if (CHARDEV_IS_SOCKET(child)) {
         save_char_socket_fd((Chardev *) child);
+    } else if (CHARDEV_IS_PTY(child)) {
+        save_char_pty_fd((Chardev *) child);
     }
     return 0;
 }
diff --git a/include/chardev/char.h b/include/chardev/char.h
index 80a9cf8..c18bda8 100644
--- a/include/chardev/char.h
+++ b/include/chardev/char.h
@@ -294,5 +294,6 @@  void qemu_chr_parse_vc(QemuOpts *opts, ChardevBackend *backend, Error **errp);
 
 void save_char_socket_fd(Chardev *);
 void load_char_socket_fd(Chardev *);
+void save_char_pty_fd(Chardev *);
 
 #endif