[PATCH V4 24/24] xl: update configuration when we unplug a device

[Wei Liu <wei.liu2@citrix.com>]

Some macros are written to accomplish following tasks:
1. load domain configuration
2. allocate a new array of devices
3. copy the devices that are to be remain in configuration
4. replace pointer in libxl_domain_config
5. store domain configuration

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 tools/libxl/xl_cmdimpl.c |   83 ++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 69 insertions(+), 14 deletions(-)

diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 91172c5..ae3df6e 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -411,6 +411,59 @@ static void *xrealloc(void *ptr, size_t sz) {
         libxl_domain_config_dispose((d_config));                        \
     } while (0)
 
+#define COMPARE_DEVID(a, b) ((a)->devid == (b)->devid)
+#define COMPARE_DISK(a, b) (!strcmp((a)->vdev, (b)->vdev))
+#define COMPARE_PCI(a, b) ((a)->bus == (b)->bus &&      \
+                               (a)->dev == (b)->dev &&  \
+                           (a)->func == (b)->func)
+
+/* Remove / destroy a device and update the stored configuration */
+#define REMOVEDESTROY_DEVICE(devtype,domid,dev,ptr,cnt,                 \
+                             compare,removedestroy)                     \
+    do {                                                                \
+        libxl_domain_config d_config;                                   \
+        libxl_device_ ## devtype *p = NULL, *x;                         \
+        int num;                                                        \
+        int j, k;                                                       \
+                                                                        \
+        libxl_domain_config_init(&d_config);                            \
+        load_domain_config((domid), &d_config);                         \
+                                                                        \
+        k = 0;                                                          \
+        for (j = 0; j < d_config.cnt; j++) {                            \
+            x = d_config.ptr + j;                                       \
+            if (compare(x, &(dev)))                                     \
+                k++;                                                    \
+        }                                                               \
+                                                                        \
+        num = d_config.cnt - k;                                         \
+                                                                        \
+        p = xrealloc(p, sizeof(*p) * num);                              \
+                                                                        \
+        k = 0;                                                          \
+        for (j = 0; j < d_config.cnt; j++) {                            \
+            x = d_config.ptr + j;                                       \
+            if (compare(x, &(dev)))                                     \
+                continue;                                               \
+            libxl_device_ ## devtype ## _copy(ctx, &p[k],               \
+                                              d_config.ptr + j);        \
+            k++;                                                        \
+        }                                                               \
+                                                                        \
+        if (libxl_device_ ## devtype ## _ ## removedestroy(ctx,(domid), \
+                                                &(dev), 0)) {           \
+            fprintf(stderr, "libxl_device_%s_remove failed.\n", #devtype); \
+            exit(1);                                                    \
+        }                                                               \
+                                                                        \
+        free(d_config.ptr);                                             \
+        d_config.ptr = p;                                               \
+        d_config.cnt = num;                                             \
+                                                                        \
+        store_domain_config((domid), &d_config);                        \
+        libxl_domain_config_dispose(&d_config);                         \
+    } while (0)
+
 #define LOG(_f, _a...)   dolog(__FILE__, __LINE__, __func__, _f "\n", ##_a)
 
 static void dolog(const char *file, int line, const char *func, char *fmt, ...)
@@ -3048,9 +3101,11 @@ static void pcidetach(uint32_t domid, const char *bdf, int force)
         exit(2);
     }
     if (force)
-        libxl_device_pci_destroy(ctx, domid, &pcidev, 0);
+        REMOVEDESTROY_DEVICE(pci, domid, pcidev, pcidevs,
+                             num_pcidevs, COMPARE_PCI, destroy);
     else
-        libxl_device_pci_remove(ctx, domid, &pcidev, 0);
+        REMOVEDESTROY_DEVICE(pci, domid, pcidev, pcidevs,
+                             num_pcidevs, COMPARE_PCI, remove);
 
     libxl_device_pci_dispose(&pcidev);
     xlu_cfg_destroy(config);
@@ -6154,10 +6209,10 @@ int main_networkdetach(int argc, char **argv)
             return 1;
         }
     }
-    if (libxl_device_nic_remove(ctx, domid, &nic, 0)) {
-        fprintf(stderr, "libxl_device_nic_del failed.\n");
-        return 1;
-    }
+
+    REMOVEDESTROY_DEVICE(nic, domid, nic, nics, num_nics,
+                         COMPARE_DEVID, remove);
+
     libxl_device_nic_dispose(&nic);
     return 0;
 }
@@ -6254,10 +6309,10 @@ int main_blockdetach(int argc, char **argv)
         fprintf(stderr, "Error: Device %s not connected.\n", argv[optind+1]);
         return 1;
     }
-    rc = libxl_device_disk_remove(ctx, domid, &disk, 0);
-    if (rc) {
-        fprintf(stderr, "libxl_device_disk_remove failed.\n");
-    }
+
+    REMOVEDESTROY_DEVICE(disk, domid, disk, disks, num_disks,
+                         COMPARE_DISK, remove);
+
     libxl_device_disk_dispose(&disk);
     return rc;
 }
@@ -6382,10 +6437,10 @@ int main_vtpmdetach(int argc, char **argv)
             return 1;
         }
     }
-    rc = libxl_device_vtpm_remove(ctx, domid, &vtpm, 0);
-    if (rc) {
-        fprintf(stderr, "libxl_device_vtpm_remove failed.\n");
-    }
+
+    REMOVEDESTROY_DEVICE(vtpm, domid, vtpm, vtpms, num_vtpms,
+                         COMPARE_DEVID, remove);
+
     libxl_device_vtpm_dispose(&vtpm);
     return rc;
 }
-- 
1.7.10.4