[Xen-changelog] [xen-3.1-testing] [HVM] Save/restore: don't leak shared-memory segments after HVM

["Xen patchbot-3.1-testing" <patchbot-3.1-testing@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1203529827 0
# Node ID c374d4d0945c5b335d380e707936ccc0958d3950
# Parent  4fb1c626023ea35e83da0e74786516d8a9b2894d
[HVM] Save/restore: don't leak shared-memory segments after HVM
live-migrate.
Signed-off-by: Tim Deegan <Tim.Deegan@xxxxxxxxxxxxx>
xen-unstable changeset:   15645:07655ed2fe58ebf883b8a4b5c2dccf15576f4778
xen-unstable date:        Thu Jul 26 12:00:32 2007 +0100
---
 tools/xcutils/xc_save.c |   25 ++++++++++++++++++-------
 1 files changed, 18 insertions(+), 7 deletions(-)

diff -r 4fb1c626023e -r c374d4d0945c tools/xcutils/xc_save.c
--- a/tools/xcutils/xc_save.c   Mon Feb 18 17:19:08 2008 +0000
+++ b/tools/xcutils/xc_save.c   Wed Feb 20 17:50:27 2008 +0000
@@ -54,7 +54,17 @@ static int suspend(int domid)
 
 static char *qemu_active_path;
 static char *qemu_next_active_path;
+static int qemu_shmid = -1;
 static struct xs_handle *xs;
+
+
+/* Mark the shared-memory segment for destruction */
+static void qemu_destroy_buffer(void)
+{
+    if (qemu_shmid != -1)
+        shmctl(qemu_shmid, IPC_RMID, NULL);
+    qemu_shmid = -1;
+}
 
 /* Get qemu to change buffers. */
 static void qemu_flip_buffer(int domid, int next_active)
@@ -97,22 +107,23 @@ static void * init_qemu_maps(int domid, 
 {
     key_t key;
     char key_ascii[17] = {0,};
-    int shmid = -1;
     void *seg; 
     char *path, *p;
 
     /* Make a shared-memory segment */
-    while (shmid == -1)
-    {
+    do {
         key = rand(); /* No security, just a sequence of numbers */
-        shmid = shmget(key, 2 * bitmap_size, 
+        qemu_shmid = shmget(key, 2 * bitmap_size, 
                        IPC_CREAT|IPC_EXCL|S_IRUSR|S_IWUSR);
-        if (shmid == -1 && errno != EEXIST)
+        if (qemu_shmid == -1 && errno != EEXIST)
             errx(1, "can't get shmem to talk to qemu-dm");
-    }
+    } while (qemu_shmid == -1);
+
+    /* Remember to tidy up after ourselves */
+    atexit(qemu_destroy_buffer);
 
     /* Map it into our address space */
-    seg = shmat(shmid, NULL, 0);
+    seg = shmat(qemu_shmid, NULL, 0);
     if (seg == (void *) -1) 
         errx(1, "can't map shmem to talk to qemu-dm");
     memset(seg, 0, 2 * bitmap_size);

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