* prevent ambiguous account registration

git-svn-id: http://opensvn.csie.org/pttbbs/trunk/pttbbs@4752 63ad8ddf-47c3-0310-b6dd-a9e9d9715204

1 files changed, 68 insertions, 0 deletions

diff --git a/mbbsd/register.c b/mbbsd/register.c
index cadcdd3d..207325f4 100644
--- a/mbbsd/register.c
+++ b/mbbsd/register.c
@@ -632,6 +632,70 @@ setupnewuser(const userec_t *user)
     return uid;
 }
 
+void
+build_unambiguous_userid(char *uid)
+{
+    int i = 0;
+    const char *ambtbl[] = {
+	"0Oo",
+	"1Il",
+	NULL
+    };
+
+    for (i = 0; ambtbl[i]; )
+    {
+	size_t pos = strcspn(uid, ambtbl[i]);
+	if (!uid[pos])
+	{
+	    i++;
+	    continue;
+	}
+	uid[pos] = ambtbl[i][0];
+	uid += (pos+1);	// skip the processed character
+    }
+}
+
+int 
+find_ambiguous_userid(const char *userid)
+{
+    const char *ambchars = "0Oo1Il";
+    size_t uidlen = 0, iamb;
+    char ambuid[IDLEN+1], shmuid[IDLEN+1];
+    int i;
+
+    assert(userid && *userid);
+
+    // if NULL, found nothing.
+    iamb = strcspn(userid, ambchars);
+    if (!userid[iamb])
+	return 0;
+
+    // build un-ambiguous uid
+    uidlen = strlcpy(ambuid, userid, sizeof(ambuid));
+    build_unambiguous_userid(ambuid);
+
+    for (i = 0; i < MAX_USERS; i++)
+    {
+	const char *ruid = SHM->userid[i];
+
+	// quick test: same non-amb prefix, and remote uid has amb characters
+	if (iamb > 0 && tolower(*ruid) != tolower(*ambuid))
+	    continue;
+	if (!ruid[strcspn(ruid, ambchars)])
+	    continue;
+
+	// copy and check remote uid length
+	if (strlcpy(shmuid, ruid, sizeof(shmuid)) != uidlen)
+	    continue;
+
+	build_unambiguous_userid(shmuid);
+	if (strcasecmp(shmuid, ambuid) == 0)
+	    return 1;
+    }
+
+    return 0;
+}
+
 /////////////////////////////////////////////////////////////////////////////
 // New Registration (Phase 1: Create Account)
 /////////////////////////////////////////////////////////////////////////////
@@ -705,6 +769,10 @@ new_register(void)
 	} 
 	else if (reserved_user_id(passbuf))
 	    outs("此代號已由系統保留，請使用別的代號\n");
+#ifndef NO_CHECK_AMBIGUOUS_USERID
+	else if (find_ambiguous_userid(passbuf))
+	    outs("此代號過於近似它人帳號，請改用別的代號。\n");
+#endif
 	else // success
 	    break;
     }