Patchwork [2/2] char: Prevent multiple devices opening same chardev

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Submitter Amit Shah
Date March 15, 2011, 9 a.m.
Message ID <5a8335528d2b75d06a54bc931b919432cf2329ea.1300179439.git.amit.shah@redhat.com>
Download mbox | patch
Permalink /patch/86900/
State New
Headers show

Comments

Amit Shah - March 15, 2011, 9 a.m.
Prevent:

-chardev socket,path=/tmp/foo,server,nowait,id=c0 \
-device virtserialport,chardev=c0,id=vs0 \
-device virtserialport,chardev=c0,id=vs1

Reported-by: Mike Cao <bcao@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 hw/qdev-properties.c |    7 ++++++-
 qemu-char.c          |    4 ++++
 qemu-char.h          |    1 +
 3 files changed, 11 insertions(+), 1 deletions(-)

Patch

diff --git a/hw/qdev-properties.c b/hw/qdev-properties.c
index a45b61e..1088a26 100644
--- a/hw/qdev-properties.c
+++ b/hw/qdev-properties.c
@@ -351,8 +351,13 @@  static int parse_chr(DeviceState *dev, Property *prop, const char *str)
     CharDriverState **ptr = qdev_get_prop_ptr(dev, prop);
 
     *ptr = qemu_chr_find(str);
-    if (*ptr == NULL)
+    if (*ptr == NULL) {
         return -ENOENT;
+    }
+    if ((*ptr)->assigned) {
+        return -EEXIST;
+    }
+    (*ptr)->assigned = 1;
     return 0;
 }
 
diff --git a/qemu-char.c b/qemu-char.c
index bd4e944..524cdc1 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -197,6 +197,10 @@  void qemu_chr_add_handlers(CharDriverState *s,
                            IOEventHandler *fd_event,
                            void *opaque)
 {
+    if (!opaque) {
+        /* chr driver being released. */
+        s->assigned = 0;
+    }
     s->chr_can_read = fd_can_read;
     s->chr_read = fd_read;
     s->chr_event = fd_event;
diff --git a/qemu-char.h b/qemu-char.h
index 56d9954..fb96eef 100644
--- a/qemu-char.h
+++ b/qemu-char.h
@@ -70,6 +70,7 @@  struct CharDriverState {
     char *label;
     char *filename;
     int opened;
+    int assigned; /* chardev assigned to a device */
     QTAILQ_ENTRY(CharDriverState) next;
 };