afs: Introduce afs_IsPagId()

Many places in the code contain a check like this, in order to check
if a given uid number represents a PAG:

    if (((uid >> 24) & 0xff) == 'A')

Consolidate these checks into a single function, called afs_IsPagId.

Change-Id: I8b9e9a8fc07672a3e1edfd2eff8227d8c2558a0a
Reviewed-on: https://gerrit.openafs.org/14086
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Cheyenne Wills <cwills@sinenomine.net>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>

src/afs/DARWIN/osi_groups.c

@@ -74,7 +74,7 @@ Afs_xsetgroups(p, args, retval)
     pcred_unlock(p);
 
     if (PagInCred(cr) == NOPAG) {
-	if (((treq.uid >> 24) & 0xff) == 'A') {
+	if (afs_IsPagId(treq.uid)) {
 	    AFS_GLOCK();
 	    /* we've already done a setpag, so now we redo it */
 	    AddPag(p, treq.uid, &cr);

src/afs/FBSD/osi_groups.c

@@ -58,7 +58,7 @@ Afs_xsetgroups(struct thread *td, struct setgroups_args *uap)
     cr = crdup(td->td_ucred);
 
     if (PagInCred(cr) == NOPAG) {
-	if (((treq.uid >> 24) & 0xff) == 'A') {
+	if (afs_IsPagId(treq.uid)) {
 	    AFS_GLOCK();
 	    /* we've already done a setpag, so now we redo it */
 	    AddPag(td, treq.uid, &cr);

src/afs/HPUX/osi_groups.c

@@ -47,7 +47,7 @@ Afs_xsetgroups()
      * overwrite it with the old pag.
      */
     if (PagInCred(p_cred(u.u_procp)) == NOPAG) {
-	if (((treq.uid >> 24) & 0xff) == 'A') {
+	if (afs_IsPagId(treq.uid)) {
 	    struct ucred *cred;
 	    AFS_GLOCK();
 	    /* we've already done a setpag, so now we redo it */

src/afs/IRIX/osi_groups.c

@@ -67,7 +67,7 @@ fixup_pags(int **credpp, int ngroups, gid_t * gidset, int old_afs_pag,
     }
     if (ngroups >= 1) {		/* possibly a DFS PAG */
 	new_dfs_pag = (int)groups[ngroups - 1];
-	if (((new_dfs_pag >> 24) & 0xff) == 'A')
+	if (afs_IsPagId(new_dfs_pag))
 	    new_dfs_pag = (int)groups[ngroups - 1];
 	else
 	    new_dfs_pag = 0;
@@ -138,7 +138,7 @@ osi_DFSGetPagFromCred(struct ucred *credp)
      *  the first or third group entry.
      */
     pag = credp->cr_groups[ngroups - 1];
-    if (((pag >> 24) & 0xff) == 'A')
+    if (afs_IsPagId(pag))
 	return pag;
     else
 	return NOPAG;

src/afs/LINUX/osi_groups.c

@@ -39,7 +39,7 @@ afs_linux_pag_from_groups(struct group_info *group_info)
 
     for (i = 0; i < group_info->ngroups; i++) {
 	g0 = afs_from_kgid(GROUP_AT(group_info, i));
-	if (((g0 >> 24) & 0xff) == 'A')
+	if (afs_IsPagId(g0))
 	    return g0;
     }
     return NOPAG;
@@ -61,7 +61,7 @@ afs_linux_pag_to_groups(afs_uint32 newpag,
 
     for (i = 0, j = 0; i < old->ngroups; ++i) {
 	afs_kgid_t ths = GROUP_AT(old, i);
-	if ((afs_from_kgid(ths) >> 24) == 'A')
+	if (afs_IsPagId(afs_from_kgid(ths)))
 	    continue;
 	if ((i == 0 || !gid_lt(newkgid, GROUP_AT(old, i - 1))) &&
 	    gid_lt(newkgid, ths)) {
@@ -658,7 +658,7 @@ osi_get_keyring_pag(afs_ucred_t *cred)
 		/* Only set PAG in groups if needed,
 		 * and the creds are from the current process */
 		if (afs_linux_cred_is_current(cred) &&
-		    ((keyring_pag >> 24) & 0xff) == 'A' &&
+		    afs_IsPagId(keyring_pag) &&
 		    keyring_pag != afs_linux_pag_from_groups(current_group_info())) {
 
 		    __setpag(&cred, keyring_pag, &newpag, 0, NULL);

src/afs/NBSD/osi_groups.c

@@ -65,7 +65,7 @@ Afs_xsetgroups(afs_proc_t *p, const void *args, register_t *retval)
      * overwrite it with the old pag.
      */
     if (PagInCred(cred) == NOPAG) {
-	if (((treq.uid >> 24) & 0xff) == 'A') {
+	if (afs_IsPagId(treq.uid)) {
 	    AFS_GLOCK();
 	    /* we've already done a setpag, so now we redo it */
 	    AddPag(p, treq.uid, &cred);

src/afs/OBSD/osi_groups.c

@@ -61,7 +61,7 @@ Afs_xsetgroups(p, args, retval)
      * overwrite it with the old pag.
      */
     if (PagInCred(p->p_rcred) == NOPAG) {
-	if (((treq.uid >> 24) & 0xff) == 'A') {
+	if (afs_IsPagId(treq.uid)) {
 	    AFS_GLOCK();
 	    /* we've already done a setpag, so now we redo it */
 	    AddPag(p, treq.uid, &p->p_rcred);

src/afs/SOLARIS/osi_groups.c

@@ -60,7 +60,7 @@ afs_xsetgroups(u_int uap, gid_t *rvp)
      * overwrite it with the old pag.
      */
     if (PagInCred(proc->p_cred) == NOPAG) {
-	if (((treq.uid >> 24) & 0xff) == 'A') {
+	if (afs_IsPagId(treq.uid)) {
 	    AFS_GLOCK();
 	    /* we've already done a setpag, so now we redo it */
 	    AddPag(treq.uid, &proc->p_cred);
@@ -93,7 +93,7 @@ pag_to_gidset(afs_uint32 pagvalue, gid_t *gidset, int *a_ngroups,
 
     /* See if we already have a PAG gid */
     for (i = 0; i < ngroups; i++) {
-        if (((gidset[i] >> 24) & 0xff) == 'A') {
+	if (afs_IsPagId(gidset[i])) {
             gidslot = &gidset[i];
             break;
         }
@@ -276,7 +276,7 @@ osi_get_group_pag(struct cred *cred) {
     ngroups = crgetngroups(cred);
 
     for (i = 0; i < ngroups; i++) {
-        if (((gidset[i] >> 24) & 0xff) == 'A') {
+	if (afs_IsPagId(gidset[i])) {
             return gidset[i];
         }
     }

src/afs/afs_osi_pag.c

@@ -575,7 +575,7 @@ afs_get_pag_from_groups(gid_t g0a, gid_t g1a)
 	return ret;
 # else
 	/* Additional testing */
-	if (((ret >> 24) & 0xff) == 'A')
+	if (afs_IsPagId(ret))
 	    return ret;
 # endif /* UKERNEL */
     }
@@ -713,3 +713,12 @@ PagInCred(afs_ucred_t *cred)
 #endif
     return pag;
 }
+
+int
+afs_IsPagId(afs_uint32 id)
+{
+    if (((id >> 24) & 0xff) == 'A') {
+	return 1;
+    }
+    return 0;
+}

src/afs/afs_prototypes.h

@@ -541,6 +541,7 @@ extern void afs_DestroyReq(struct vrequest *av);
 extern afs_uint32 afs_get_pag_from_groups(gid_t g0a, gid_t g1a);
 extern void afs_get_groups_from_pag(afs_uint32 pag, gid_t * g0p, gid_t * g1p);
 extern afs_int32 PagInCred(afs_ucred_t *cred);
+extern int afs_IsPagId(afs_uint32 id);
 
 /* afs_osi_uio.c */
 #if !defined(AFS_DARWIN80_ENV)

src/afs/afs_user.c

@@ -782,7 +782,7 @@ afs_GCPAGs(afs_int32 * ReleasedCount)
     for (i = 0; i < NUSERS; i++) {
 	for (pu = afs_users[i]; pu; pu = pu->next) {
 	    pu->states |= TMP_UPAGNotReferenced;
-	    if (((pu->uid >> 24) & 0xff) != 'A') {
+	    if (afs_IsPagId(pu->uid)) {
 		/* this is a uid-based token, */
 		/* increment the count */
 		afs_GCPAGs_UIDBaseTokenCount++;