Windows: pioctl path retrying with \\afs\all

When the redirector is in use, \\AFS is identified as being an AFS path.
With the SMB redirector, \\AFS was not considered a valid path.  In order
to simulate the notion of \\AFS being the root volume, failover logic
was added to the symlink and fs modules being triggered that
would retry a request for \\afs\foo as \\afs\all\foo.

The VIOC_SYMLINK and VIOC_AFS_CREATE_MT_PT pioctls are broken.  The
'path' parameter that is passed in contains the directory entry that
is to be created.  Since the AFS redirector maps \\afs to the root.afs
volume the "foo" in \\afs\foo must exist in order for the
_._AFS_IOCTL_._ special file to be opened.

This patch implements an alternative to the failover.  If the opcode
is one of the two listed above and the input path is a UNC path,
then the path is re-written as \\AFS\all.  This is necessary because
the repeated attempts to open a UNC path through the SMB redirector
with different usernames can result in the smb session becoming
disconnected.  If this is done when the SYSTEM account is in use,
the tokens associated with the connection can be lost.

LICENSE MIT

Change-Id: I2c2f6c08c7ca5c137062d34e1353731b6f78f633
Reviewed-on: http://gerrit.openafs.org/5336
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>

src/sys/pioctl_nt.c

@@ -33,7 +33,7 @@
 #include <cm_dir.h>
 #include <cm_utils.h>
 #include <cm_ioctl.h>
-
+#include <smb_iocons.h>
 #include <smb.h>
 #include <pioctl_nt.h>
 #include <WINNT/afsreg.h>
@@ -1231,8 +1231,97 @@ pioctl_int(char *pathp, afs_int32 opcode, struct ViceIoctl *blobp, afs_int32 fol
     long code;
     long temp;
     char fullPath[1000];
+    char altPath[1024];
     HANDLE reqHandle;
     int save;
+    int i,j,count,all;
+
+    /*
+     * The pioctl operations for creating a mount point and a symlink are broken.
+     * Instead of 'pathp' referring to the directory object in which the symlink
+     * or mount point within which the new object is to be created, 'pathp' refers
+     * to the object itself.  This results in a problem when the object being created
+     * is located within the Freelance root.afs volume.  \\afs\foo will not be a
+     * valid share name since the 'foo' object does not yet exist.  Therefore,
+     * \\afs\foo\_._.afs_ioctl_._ cannot be opened.  Instead in these two cases
+     * we must force the use of the \\afs\all\foo form of the path.
+     *
+     * We cannot use this form in all cases because of smb submounts which are
+     * not located within the Freelance local root.
+     */
+    switch ( opcode ) {
+    case VIOC_AFS_CREATE_MT_PT:
+    case VIOC_SYMLINK:
+        if (pathp &&
+             (pathp[0] == '\\' && pathp[1] == '\\' ||
+              pathp[0] == '/' && pathp[1] == '/')) {
+            for (all = count = j = 0; pathp[j]; j++) {
+                if (pathp[j] == '\\' || pathp[j] == '/')
+                    count++;
+
+                /* Test to see if the second component is 'all' */
+                if (count == 3) {
+                    all = 1;
+                    for (i=0; pathp[i+j]; i++) {
+                        switch(i) {
+                        case 0:
+                            if (pathp[i+j] != 'a' &&
+                                pathp[i+j] != 'A') {
+                                all = 0;
+                                goto notall;
+                            }
+                            break;
+                        case 1:
+                        case 2:
+                            if (pathp[i+j] != 'l' &&
+                                 pathp[i+j] != 'L') {
+                                all = 0;
+                                goto notall;
+                            }
+                            break;
+                        default:
+                            all = 0;
+                            goto notall;
+                        }
+                    }
+                    if (i != 3)
+                        all = 0;
+                }
+
+              notall:
+                if (all)
+                    break;
+            }
+
+            /*
+             * if count is three and the second component is not 'all',
+             * then we are attempting to create an object in the
+             * Freelance root.afs volume.  Substitute the path.
+             */
+
+            if (count == 3 && !all) {
+                /* Normalize the name to use \\afs\all as the root */
+                for (count = i = j = 0; pathp[j] && i < sizeof(altPath); j++) {
+                    if (pathp[j] == '\\' || pathp[j] == '/') {
+                        altPath[i++] = '\\';
+                        count++;
+
+                        if (count == 3) {
+                            altPath[i++] = 'a';
+                            altPath[i++] = 'l';
+                            altPath[i++] = 'l';
+                            altPath[i++] = '\\';
+                            count++;
+                        }
+                    } else {
+                        altPath[i++] = pathp[j];
+                    }
+                }
+                altPath[i] = '\0';
+                pathp = altPath;
+            }
+        }
+    }
 
     code = GetIoctlHandle(pathp, &reqHandle);
     if (code) {