Merge remote-tracking branch 'remotes/mjt/tags/pull-trivial-patches-2015-11-06' into staging

trivial patches for 2015-11-06

# gpg: Signature made Fri 06 Nov 2015 12:42:43 GMT using RSA key ID A4C3D7DB
# gpg: Good signature from "Michael Tokarev <mjt@tls.msk.ru>"
# gpg:                 aka "Michael Tokarev <mjt@corpit.ru>"
# gpg:                 aka "Michael Tokarev <mjt@debian.org>"

* remotes/mjt/tags/pull-trivial-patches-2015-11-06: (24 commits)
  tap-bsd: use user-specified tap device if it already exists
  qemu-sockets: do not test path with access() before unlinking
  taget-ppc: Fix read access to IBAT registers higher than IBAT3
  exec: avoid unnecessary cacheline bounce on ram_list.mru_block
  target-alpha: fix uninitialized variable
  ivshmem-server: fix possible OVERRUN
  pci-assign: do not test path with access() before opening
  qom/object: fix 2 comment typos
  configure: remove help string for 'vnc-tls' option
  usb: Use g_new() & friends where that makes obvious sense
  qxl: Use g_new() & friends where that makes obvious sense
  ui: Use g_new() & friends where that makes obvious sense
  bt: fix use of uninitialized variable seqlen
  hw/dma/pxa2xx: Remove superfluous memset
  linux-user/syscall: Replace g_malloc0 + memcpy with g_memdup
  tests/i44fx-test: No need for zeroing memory before memset
  hw/input/tsc210x: Remove superfluous memset
  xen: fix invalid assertion
  tests: ignore test-qga
  fix bad indentation in pcie_cap_slot_write_config()
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 33 insertions, 5 deletions

diff --git a/net/tap-bsd.c b/net/tap-bsd.c
index 7028d9be95..0103a97bf6 100644
--- a/net/tap-bsd.c
+++ b/net/tap-bsd.c
@@ -109,8 +109,7 @@ int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
 
 #define PATH_NET_TAP "/dev/tap"
 
-int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
-             int vnet_hdr_required, int mq_required, Error **errp)
+static int tap_open_clone(char *ifname, int ifname_size, Error **errp)
 {
     int fd, s, ret;
     struct ifreq ifr;
@@ -126,7 +125,8 @@ int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
     ret = ioctl(fd, TAPGIFNAME, (void *)&ifr);
     if (ret < 0) {
         error_setg_errno(errp, errno, "could not get tap interface name");
-        goto error;
+        close(fd);
+        return -1;
     }
 
     if (ifname[0] != '\0') {
@@ -135,19 +135,47 @@ int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
         if (s < 0) {
             error_setg_errno(errp, errno,
                              "could not open socket to set interface name");
-            goto error;
+            close(fd);
+            return -1;
         }
         ifr.ifr_data = ifname;
         ret = ioctl(s, SIOCSIFNAME, (void *)&ifr);
         close(s);
         if (ret < 0) {
             error_setg(errp, "could not set tap interface name");
-            goto error;
+            close(fd);
+            return -1;
         }
     } else {
         pstrcpy(ifname, ifname_size, ifr.ifr_name);
     }
 
+    return fd;
+}
+
+int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
+             int vnet_hdr_required, int mq_required, Error **errp)
+{
+    int fd = -1;
+
+    /* If the specified tap device already exists just use it. */
+    if (ifname[0] != '\0') {
+        char dname[100];
+        snprintf(dname, sizeof dname, "/dev/%s", ifname);
+        TFR(fd = open(dname, O_RDWR));
+        if (fd < 0 && errno != ENOENT) {
+            error_setg_errno(errp, errno, "could not open %s", dname);
+            return -1;
+        }
+    }
+
+    if (fd < 0) {
+        /* Tap device not specified or does not exist. */
+        if ((fd = tap_open_clone(ifname, ifname_size, errp)) < 0) {
+            return -1;
+        }
+    }
+
     if (*vnet_hdr) {
         /* BSD doesn't have IFF_VNET_HDR */
         *vnet_hdr = 0;