This patch makes xc_linux properly deal with:
1. discovering and creating device nodes if necessary
2. the new form of xen/<dev> device names soon to be used by the kernel
This changes the logic slightly:
- If a device node already exists with the proper name, then it uses it
as-is, assuming it has already been correctly created.
- If the path doesn't exist, or it exists but isn't a device node, and
it has successfully found the major/minor for the device, then
(re)create the device node.
Since this logic is identical for gntdev and evtchn, make a common function
to handle both.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
diff -r f146aa75120c tools/libxc/xc_linux.c
--- a/tools/libxc/xc_linux.c Thu May 27 12:14:32 2010 -0700
+++ b/tools/libxc/xc_linux.c Fri May 28 16:33:11 2010 -0700
@@ -378,34 +378,73 @@
return makedev(major, minor);
}
-#define EVTCHN_DEV_NAME "/dev/xen/evtchn"
+#define DEVXEN "/dev/xen"
+
+static int make_dev_xen(void)
+{
+ if (mkdir(DEVXEN, 0755) != 0) {
+ struct stat st;
+
+ if (stat(DEVXEN, &st) != 0 || !S_ISDIR(st.st_mode))
+ return -1;
+ }
+
+ return 0;
+}
+
+static int xendev_open(const char *dev)
+{
+ int fd, devnum;
+ struct stat st;
+ char *devname, *devpath;
+
+ devname = devpath = NULL;
+ fd = -1;
+
+ if (asprintf(&devname, "xen!%s", dev) == 0)
+ goto fail;
+
+ if (asprintf(&devpath, "%s/%s", DEVXEN, dev) == 0)
+ goto fail;
+
+ devnum = xc_find_device_number(dev);
+ if (devnum == -1)
+ devnum = xc_find_device_number(devname);
+
+ /*
+ * If we know what the correct device is and the path doesn't
+ * exist or isn't a device, then remove it so we can create the
+ * device.
+ */
+ if (devnum != -1 &&
+ (stat(devpath, &st) != 0 || !S_ISCHR(st.st_mode))) {
+ unlink(devpath);
+
+ if (make_dev_xen() == -1)
+ goto fail;
+
+ if (mknod(devpath, S_IFCHR|0600, devnum) != 0) {
+ PERROR("Couldn't make %s", devpath);
+ goto fail;
+ }
+ }
+
+ fd = open(devpath, O_RDWR);
+
+ if (fd == -1)
+ PERROR("Could not open %s", devpath);
+
+fail:
+ free(devname);
+ free(devpath);
+
+ return fd;
+}
+
int xc_evtchn_open(void)
{
- struct stat st;
- int fd;
- int devnum;
-
- devnum = xc_find_device_number("evtchn");
-
- /* Make sure any existing device file links to correct device. */
- if ( (lstat(EVTCHN_DEV_NAME, &st) != 0) || !S_ISCHR(st.st_mode) ||
- (st.st_rdev != devnum) )
- (void)unlink(EVTCHN_DEV_NAME);
-
- reopen:
- if ( (fd = open(EVTCHN_DEV_NAME, O_RDWR)) == -1 )
- {
- if ( (errno == ENOENT) &&
- ((mkdir("/dev/xen", 0755) == 0) || (errno == EEXIST)) &&
- (mknod(EVTCHN_DEV_NAME, S_IFCHR|0600, devnum) == 0) )
- goto reopen;
-
- PERROR("Could not open event channel interface");
- return -1;
- }
-
- return fd;
+ return xendev_open("evtchn");
}
int xc_evtchn_close(int xce_handle)
@@ -519,34 +558,9 @@
errno = saved_errno;
}
-#define GNTTAB_DEV_NAME "/dev/xen/gntdev"
-
int xc_gnttab_open(void)
{
- struct stat st;
- int fd;
- int devnum;
-
- devnum = xc_find_device_number("gntdev");
-
- /* Make sure any existing device file links to correct device. */
- if ( (lstat(GNTTAB_DEV_NAME, &st) != 0) || !S_ISCHR(st.st_mode) ||
- (st.st_rdev != devnum) )
- (void)unlink(GNTTAB_DEV_NAME);
-
-reopen:
- if ( (fd = open(GNTTAB_DEV_NAME, O_RDWR)) == -1 )
- {
- if ( (errno == ENOENT) &&
- ((mkdir("/dev/xen", 0755) == 0) || (errno == EEXIST)) &&
- (mknod(GNTTAB_DEV_NAME, S_IFCHR|0600, devnum) == 0) )
- goto reopen;
-
- PERROR("Could not open grant table interface");
- return -1;
- }
-
- return fd;
+ return xendev_open("gntdev");
}
int xc_gnttab_close(int xcg_handle)
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