[V9,37/46] chardev: cpr for simple devices

Commit Message

Steven Sistare July 26, 2022, 4:10 p.m. UTC

Set QEMU_CHAR_FEATURE_CPR for devices that trivially support cpr-exec.
char-stdio is slightly less trivial.  Allow the gdb server by
closing it on exec.

Signed-off-by: Steve Sistare <[e-mail]>
---
 MAINTAINERS           |  1 +
 chardev/char-mux.c    |  1 +
 chardev/char-null.c   |  1 +
 chardev/char-serial.c |  1 +
 chardev/char-stdio.c  | 31 +++++++++++++++++++++++++++++++
 gdbstub.c             |  1 +
 stubs/meson.build     |  1 +
 stubs/migration.c     | 33 +++++++++++++++++++++++++++++++++
 8 files changed, 70 insertions(+)
 create mode 100644 stubs/migration.c

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index 3af099a..b93b0bb 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3038,6 +3038,7 @@  F: tests/qtest/migration-test.c
 F: docs/devel/migration.rst
 F: qapi/migration.json
 F: tests/migration/
+F: stubs/migration.c
 
 D-Bus
 M: Marc-André Lureau <[e-mail]>
diff --git a/chardev/char-mux.c b/chardev/char-mux.c
index ee2d47b..d47fa31 100644
--- a/chardev/char-mux.c
+++ b/chardev/char-mux.c
@@ -337,6 +337,7 @@  static void qemu_chr_open_mux(Chardev *chr,
      */
     *be_opened = muxes_opened;
     qemu_chr_fe_init(&d->chr, drv, errp);
+    qemu_chr_set_feature(chr, QEMU_CHAR_FEATURE_CPR);
 }
 
 static void qemu_chr_parse_mux(QemuOpts *opts, ChardevBackend *backend,
diff --git a/chardev/char-null.c b/chardev/char-null.c
index 1c6a290..02acaff 100644
--- a/chardev/char-null.c
+++ b/chardev/char-null.c
@@ -32,6 +32,7 @@  static void null_chr_open(Chardev *chr,
                           Error **errp)
 {
     *be_opened = false;
+    qemu_chr_set_feature(chr, QEMU_CHAR_FEATURE_CPR);
 }
 
 static void char_null_class_init(ObjectClass *oc, void *data)
diff --git a/chardev/char-serial.c b/chardev/char-serial.c
index 4b0b83d..7aa2042 100644
--- a/chardev/char-serial.c
+++ b/chardev/char-serial.c
@@ -277,6 +277,7 @@  static void qmp_chardev_open_serial(Chardev *chr,
     }
     tty_serial_init(fd, 115200, 'N', 8, 1);
 
+    qemu_chr_set_feature(chr, QEMU_CHAR_FEATURE_CPR);
     qemu_chr_open_fd(chr, fd, fd);
 }
 #endif /* __linux__ || __sun__ */
diff --git a/chardev/char-stdio.c b/chardev/char-stdio.c
index 3c64867..7a96bdc 100644
--- a/chardev/char-stdio.c
+++ b/chardev/char-stdio.c
@@ -27,6 +27,7 @@ 
 #include "qemu/option.h"
 #include "qemu/sockets.h"
 #include "qapi/error.h"
+#include "migration/misc.h"
 #include "chardev/char.h"
 
 #ifdef _WIN32
@@ -40,19 +41,46 @@ 
 #ifndef _WIN32
 /* init terminal so that we can grab keys */
 static struct termios oldtty;
+static struct termios newtty;
 static int old_fd0_flags;
+static int new_fd0_flags;
 static bool stdio_in_use;
 static bool stdio_allow_signal;
 static bool stdio_echo_state;
+static Notifier cpr_notifier;
 
 static void term_exit(void)
 {
     if (stdio_in_use) {
+        tcgetattr(0, &newtty);
+        new_fd0_flags = fcntl(0, F_GETFL);
+
         tcsetattr(0, TCSANOW, &oldtty);
         fcntl(0, F_SETFL, old_fd0_flags);
     }
 }
 
+static void term_reenter(void)
+{
+    if (stdio_in_use) {
+        tcsetattr(0, TCSANOW, &newtty);
+        fcntl(0, F_SETFL, new_fd0_flags);
+    }
+}
+
+static void term_cpr_exec_notifier(Notifier *notifier, void *data)
+{
+    MigrationState *s = data;
+
+    if (migrate_mode_of(s) == MIG_MODE_CPR_EXEC) {
+        if (migration_has_finished(s)) {
+            term_exit();
+        } else if (migration_has_failed(s)) {
+            term_reenter();
+        }
+    }
+}
+
 static void qemu_chr_set_echo_stdio(Chardev *chr, bool echo)
 {
     struct termios tty;
@@ -117,6 +145,8 @@  static void qemu_chr_open_stdio(Chardev *chr,
 
     stdio_allow_signal = !opts->has_signal || opts->signal;
     qemu_chr_set_echo_stdio(chr, false);
+    qemu_chr_set_feature(chr, QEMU_CHAR_FEATURE_CPR);
+    migration_add_notifier(&cpr_notifier, term_cpr_exec_notifier);
 }
 #endif
 
@@ -147,6 +177,7 @@  static void char_stdio_finalize(Object *obj)
 {
 #ifndef _WIN32
     term_exit();
+    migration_remove_notifier(&cpr_notifier);
 #endif
 }
 
diff --git a/gdbstub.c b/gdbstub.c
index cf869b1..08b3d80 100644
--- a/gdbstub.c
+++ b/gdbstub.c
@@ -3616,6 +3616,7 @@  int gdbserver_start(const char *device)
         mon_chr = gdbserver_state.mon_chr;
         reset_gdbserver_state();
     }
+    mon_chr->reopen_on_cpr = true;
 
     create_processes(&gdbserver_state);
 
diff --git a/stubs/meson.build b/stubs/meson.build
index 392b1b5..a1eda95 100644
--- a/stubs/meson.build
+++ b/stubs/meson.build
@@ -27,6 +27,7 @@  if libaio.found()
   stub_ss.add(files('linux-aio.c'))
 endif
 stub_ss.add(files('migr-blocker.c'))
+stub_ss.add(files('migration.c'))
 stub_ss.add(files('module-opts.c'))
 stub_ss.add(files('monitor.c'))
 stub_ss.add(files('monitor-core.c'))
diff --git a/stubs/migration.c b/stubs/migration.c
new file mode 100644
index 0000000..f2f79bd
--- /dev/null
+++ b/stubs/migration.c
@@ -0,0 +1,33 @@ 
+/*
+ * Copyright (c) 2021, 2022 Oracle and/or its affiliates.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "migration/misc.h"
+
+void migration_add_notifier(Notifier *notify,
+                            void (*cb)(Notifier *notifier, void *data))
+{
+}
+
+void migration_remove_notifier(Notifier *notify)
+{
+}
+
+bool migration_has_finished(MigrationState *s)
+{
+    return false;
+}
+
+bool migration_has_failed(MigrationState *s)
+{
+    return false;
+}
+
+MigMode migrate_mode_of(MigrationState *s)
+{
+    return 0;
+}