@@ -8,16 +8,18 @@ ## design
 
 This is the working structure of the 9p filesystem:
 
-* `/ctl`: Write-only control file for inputing system commands
-  * `login PW`: Authenticate with `xrxs` -- password is hashed against realm password hash
-  * `load CART`: Load a cartridge
-  * `chunk TYPE N`: Load data of type TYPE and chunk number N
+* `/ctl`: Read/write control file for inputing system commands. Reading the file shows the status of the last input command: 1 for success, 0 for failure; `logout` is a special case, and the status code will be -1 if it was succesful. the following are valid command syntax:
+  * `login PW`: Authenticate with `xrxs` -- password is hashed against realm password hash.
+  * `logout`: Gracefully remove yourself from the users table.
+  * `load CART`: Load a cartridge.
+  * `chunk TYPE N`: Load data of type TYPE and chunk number N.
   * `create REALM`: Create a new realm (start a new game) -- must have a cartridge loaded
   * `protect PW`: Protect the curent realm with a password if you are the master.
   * `transfer USER`: Transfer ownership of the realm to another user.
-  * `enter REALM`: Join an existing realm
-  * `leave`: Leave the current realm
-  * `unload`: Unload the cartridge
+  * `delete REALM`: Delete the realm off the server if you are the master and it is empty.
+  * `enter REALM`: Join an existing realm.
+  * `leave`: Leave the current realm.
+  * `unload`: Unload the cartridge.
   
 * `/users`: Read-only; Self and others in the realm are readable from here, one per line. It contains only yourself before joining a realm. Your username on your machine is used as your username in `xrxs` -- if your name is taken, you will get an error on attaching.
 
@@ -36,6 +38,13 @@
 * `/random`: Read-only, get a random number from 0 to 99.
 
 * `/grandom`: Read-only, get a random number from 0 to 99 -- These are doled out on a per-realm basis, and the number stays the same until everyone in the realm has had a chance to read it. If you've already read it this round or aren't in a realm, it will be empty.
+
+## configuration
+
+`config.h` in the source contains the following configuration macros:
+
+  * `MAX_USERS`: the maximum number of simultaneous users able to attach to the `xrxs` service
+  * `DATA_DIR`: the path to the root of the cartridge and realm storage; can be absolute or relative to the `xrxs` executable, but must have the trailing `/`
 
 ## realm format
 

@@ -1,18 +1,19 @@
 #include <u.h>
 #include <libc.h>
+#include "config.h"
 #include "util.h"
 #include "user.h"
 #include "cart.h"
 
 Cart* create_cart(char* name) {
-  char path[64] = {0};
-  char file[64] = {0};
+  char path[256] = {0};
+  char file[256] = {0};
   Cart* cart;
   Blob* cart_data;
 
-  scat(path, "carts/");
+  scat(path, DATA_DIR);
   scat(path, name);
-  scpy(path, file, 64);
+  scpy(path, file, 256);
   ccat(file, '/');
   scat(file, name);
   scat(file, ".rom");

@@ -5,6 +5,7 @@ CHUNK = 190974201,
   CREATE = 7083959236,
   PROTECT = 295480618573,
   TRANSFER = 11311529048177,
+  DELETE = 7129299147,
   ENTER = 195024746,
   LEAVE = 207662601,
   LOGOUT = 7702552890,

@@ -0,0 +1,5 @@
+/* Maximum number of users on the server */
+#define MAX_USERS 64
+
+/* Path to cart/realm storage (must include trailing slash) */
+#define DATA_DIR "/home/nilix/src/xrxs/carts/"

@@ -1,6 +1,7 @@
 #include <u.h>
 #include <libc.h>
 #include <stdio.h>
+#include "config.h"
 #include "util.h"
 #include "user.h"
 #include "cart.h"
@@ -13,7 +14,7 @@ UserInfo* u = find_user(table, uname);
   char cart[32];
   int max = 4;
   char* n = name;
-  char path[128] = {0};
+  char path[256] = {0};
 
   if (u == nil || u->cart == nil)
     return 0;
@@ -28,7 +29,7 @@ n++;
     max = atoi(n);
   }
 
-  scat(path, "carts/");
+  scat(path, DATA_DIR);
   scat(path, cart);
   scat(path, "/realms/");
   if (open(path, OREAD) < 0)
@@ -55,14 +56,14 @@
 Realm* parse_realm(char* cart, char* name) {
   Realm* self;
   FILE* f;
-  char path[128] = {0};
-  char file[128] = {0};
+  char path[256] = {0};
+  char file[256] = {0};
   char buf[256] = {0};
-  scat(path, "carts/");
+  scat(path, DATA_DIR);
   scat(path, cart);
   scat(path, "/realms/");
   scat(path, name);
-  scpy(path, file, 128);
+  scpy(path, file, 256);
 
   scat(file, "/realm");
 
@@ -85,7 +86,7 @@ } else {
     return nil;
   }
 
-  scpy(path, file, 128);
+  scpy(path, file, 256);
   scat(file, "/universe");
   self->universe = parse_universe(cart, name);
   return self;
@@ -95,7 +96,7 @@ Realm* find_realm(UserInfo* table, char* name) {
   UserInfo* u = table;
   int i;
 
-  for (i = 0; i < 64; i++) {
+  for (i = 0; i < MAX_USERS; i++) {
     if (slen(u->name) > 0 && u->realm != nil && scmp(u->realm->name, name))
       return u->realm;
     u++;
@@ -105,13 +106,13 @@ }
 
 void save_realm(char* cart, Realm* self) {
   FILE* f;
-  char path[128] = {0};
-  char file[128] = {0};
-  scat(path, "carts/");
+  char path[256] = {0};
+  char file[256] = {0};
+  scat(path, DATA_DIR);
   scat(path, cart);
   scat(path, "/realms/");
   scat(path, self->name);
-  scpy(path, file, 128);
+  scpy(path, file, 256);
 
   scat(file, "/realm");
   f = fopen(file, "w");

@@ -1,6 +1,7 @@
 #include <u.h>
 #include <libc.h>
 #include <stdio.h>
+#include "config.h"
 #include "util.h"
 #include "universe.h"
 
@@ -14,7 +15,7 @@ return self;
 }
 
 Universe* parse_universe(char* cart, char* realm_name) {
-  char path[64] = {0};
+  char path[256] = {0};
   char buf[256] = {0};
   char name[16] = {0};
   char value[64] = {0};
@@ -22,7 +23,7 @@ FILE* f;
   Atom* a;
   Universe* self;
 
-  scat(path, "carts/");
+  scat(path, DATA_DIR);
   scat(path, cart);
   scat(path, "/realms/");
   scat(path, realm_name);
@@ -52,12 +53,12 @@ return nil;
 }
 
 void save_universe(char* cart, Universe* self, char* realm_name) {
-  char path[64] = {0};
+  char path[256] = {0};
   FILE* f;
   Atom* a;
   int i;
 
-  scat(path, "carts/");
+  scat(path, DATA_DIR);
   scat(path, cart);
   scat(path, "/realms/");
   scat(path, realm_name);

@@ -4,7 +4,7 @@ typedef struct Atom Atom;
 
 struct Atom {
   char name[16];
-  char value[64];
+  char value[MAX_USERS];
   Atom* next;
 };
 

@@ -1,6 +1,8 @@
 #include <u.h>
+#include <sys/stat.h>
 #include <libc.h>
 #include <stdio.h>
+#include "config.h"
 #include "util.h"
 #include "cart.h"
 #include "realm.h"
@@ -11,11 +13,18 @@
 UserInfo* find_user(UserInfo* table, char* uname) {
   UserInfo* u = table;
   int i;
-  for (i = 0; i < 64; i++) {
+  for (i = 0; i < MAX_USERS; i++) {
     if (scmp(uname, u->name))
       return u;
     u++;
   }
+  return nil;
+}
+
+int* ctl_code_handle(UserInfo* table, char* uname) {
+  UserInfo* u = find_user(table, uname);
+  if (u != nil)
+    return &(u->ctl_code);
   return nil;
 }
 
@@ -43,7 +52,7 @@ free(u->scope);
     u->scope = nil;
   }
 
-  u->random = 0;
+  u->random = -1;
 
   if (u->realm != nil)
     leave_realm(table, uname);
@@ -104,8 +113,7 @@ fprintf(stderr, "no cart\n");
     return 0;
   }
 
-  for (i = 0; i < 64; i++) {
-    fprintf(stderr, "iterating through users table: slot %d\n", i);
+  for (i = 0; i < MAX_USERS; i++) {
     if (table[i].realm != nil && scmp(table[i].realm->name, realm_name))
       j++;
   }
@@ -162,4 +170,49 @@
   destroy_cart(u->cart);
   u->cart = nil;
   return 1;
+}
+
+int delete_realm(UserInfo* table, char* uname, char* realm) {
+  UserInfo* u = find_user(table, uname);
+  char path[256] = {0};
+  char file[256] = {0};
+  Blob* realm_data;
+  char garbage[32] = {0};
+  char master[32] = {0};
+  int i;
+  if (u == nil || u->cart == nil) {
+    fprintf(stderr, "no user/cart\n");
+    return 0;
+  }
+
+  for (i = 0; i < MAX_USERS; i++) {
+    if (table[i].realm != nil && scmp(table[i].realm->name, realm)) {
+      fprintf(stderr, "realm not empty\n");
+      return 0;
+    }
+  }
+
+  scat(path, DATA_DIR);
+  scat(path, u->cart->name);
+  scat(path, "/realms/");
+  scat(path, realm);
+  scpy(path, file, 256);
+  ccat(file, '/');
+  scat(file, "realm");
+
+  fprintf(stderr, "%s\n", file);
+  realm_data = read_chars(file);
+  if (realm_data == nil)
+    return 0;
+
+  sscanf(
+    realm_data->data,
+    "%u %32s %llu",
+    (uint*)garbage,
+    master,
+    (uvlong*)garbage);
+  if (scmp(master, uname) && rm_dir(path))
+    return 1;
+  else
+    return 0;
 }

@@ -7,9 +7,11 @@ Cart* cart;
   Realm* realm;
   char* scope;
   int random;
+  int ctl_code;
 } UserInfo;
 
 UserInfo* find_user(UserInfo* table, char* uname);
+int* ctl_code_handle(UserInfo* table, char* uname);
 int login(UserInfo* table, char* uname, char* password);
 int logout(UserInfo* table, char* uname);
 int protect_realm(UserInfo* table, char* uname, char* password);
@@ -18,3 +20,4 @@ int load_cart(UserInfo* table, char* uname, char* cart_name);
 int enter_realm(UserInfo* table, char* uname, char* realm_name);
 int leave_realm(UserInfo* table, char* uname);
 int unload_cart(UserInfo* table, char* uname);
+int delete_realm(UserInfo* table, char* uname, char* realm);

@@ -1,4 +1,5 @@
 #include <u.h>
+#include <sys/stat.h>
 #include <libc.h>
 #include <stdio.h>
 #include "cart.h"
@@ -147,6 +148,59 @@ self->data = buf;
     self->length = count;
     return self;
   }
+}
+
+int issymlink(char* name) {
+  struct stat s;
+  return lstat(name, &s) >= 0 && S_ISLNK(s.st_mode);
+}
+
+int rm_dir(char* f) {
+  char* name;
+  int fd, i, j, n, ndir, nname;
+  Dir* dirbuf;
+  int fail = 0;
+
+  fd = open(f, OREAD);
+  if (fd < 0) {
+    return 0;
+  }
+  n = dirreadall(fd, &dirbuf);
+  close(fd);
+  if (n < 0) {
+    return 0;
+  }
+
+  nname = strlen(f) + 1 + STATMAX + 1; /* plenty! */
+  name = malloc(nname);
+  if (name == 0) {
+    return 0;
+  }
+
+  ndir = 0;
+  for (i = 0; i < n; i++) {
+    snprint(name, nname, "%s/%s", f, dirbuf[i].name);
+    if (remove(name) != -1 || issymlink(name))
+      dirbuf[i].qid.type = QTFILE; /* so we won't recurse */
+    else {
+      if (dirbuf[i].qid.type & QTDIR)
+        ndir++;
+      else
+        fail = 1;
+    }
+  }
+  if (ndir)
+    for (j = 0; j < n; j++)
+      if (dirbuf[j].qid.type & QTDIR) {
+        snprint(name, nname, "%s/%s", f, dirbuf[j].name);
+        rmdir(name);
+      }
+  if (remove(f) == -1)
+    fail = 1;
+
+  free(name);
+  free(dirbuf);
+  return fail ? 0 : 1;
 }
 
 void strreverse(char* begin, char* end) {

@@ -16,4 +16,5 @@ int ssin(char* str, char* substr);
 char* ccat(char* dst, char c);
 Blob* read_bytes(char* path);
 Blob* read_chars(char* path);
-void itoa(int, char*, int);+void itoa(int, char*, int);
+int rm_dir(char* path);

@@ -7,6 +7,7 @@ #include <stdio.h>
 #include <dirent.h>
 #include <libString.h>
 #include <string.h>
+#include "config.h"
 #include "err.h"
 #include "command.h"
 #include "util.h"
@@ -16,14 +17,11 @@ #include "universe.h"
 #include "realm.h"
 #include "user.h"
 
-#define CARTSPATH "./carts"
-#define REALMSPATH "./realms"
-
 int chatty9p = 1;
 
 static Tree* tree;
 
-static UserInfo users_table[64];
+static UserInfo users_table[MAX_USERS];
 
 void xrxs_attach(Req* r) {
   /* As it is, once the user detaches, they will stay in the table
@@ -36,7 +34,7 @@ int vacancy = 0;
   char* usr;
   char* username = r->ifcall.uname;
 
-  for (i = 0; i < 64; i++) {
+  for (i = 0; i < MAX_USERS; i++) {
     usr = users_table[i].name;
     if (scmp(usr, username)) {
       respond(r, EUNAME);
@@ -44,6 +42,7 @@ return;
     }
     if (*usr == 0) {
       scpy(username, usr, 32);
+      users_table[i].random = -1;
       vacancy = 1;
       break;
     }
@@ -59,6 +58,7 @@ void write_ctl(Req* r) {
   char cmd[16] = {0};
   char* c = r->ifcall.data;
   int i;
+  int* code = ctl_code_handle(users_table, r->fid->uid);
 
   for (i = 0; i < r->ifcall.count && *c != ' ' && *c != '\n'; i++) {
     ccat(cmd, *c++);
@@ -71,28 +71,31 @@ fprintf(stderr, "%s(%s)\n", cmd, c);
   uvlong const cmd_hashv = hash(cmd, 0);
   switch (cmd_hashv) {
     case LOGIN:
-      login(users_table, r->fid->uid, c);
+      *code = login(users_table, r->fid->uid, c);
       break;
     case LOAD:
-      load_cart(users_table, r->fid->uid, c);
+      *code = load_cart(users_table, r->fid->uid, c);
       break;
     case CHUNK:
-      get_chunk(users_table, r->fid->uid, c);
+      *code = get_chunk(users_table, r->fid->uid, c);
       break;
     case CREATE:
-      create_realm(users_table, r->fid->uid, c);
+      *code = create_realm(users_table, r->fid->uid, c) != nil ? 1 : 0;
       break;
     case PROTECT:
-      protect_realm(users_table, r->fid->uid, c);
+      *code = protect_realm(users_table, r->fid->uid, c);
       break;
     case TRANSFER:
-      transfer_realm(users_table, r->fid->uid, c);
+      *code = transfer_realm(users_table, r->fid->uid, c);
+      break;
+    case DELETE:
+      *code = delete_realm(users_table, r->fid->uid, c);
       break;
     case ENTER:
-      enter_realm(users_table, r->fid->uid, c);
+      *code = enter_realm(users_table, r->fid->uid, c);
       break;
     case LEAVE:
-      leave_realm(users_table, r->fid->uid);
+      *code = leave_realm(users_table, r->fid->uid);
       break;
     case LOGOUT:
       logout(users_table, r->fid->uid);
@@ -104,7 +107,7 @@ case RESET:
       // reset(r->fid->uid);
       break;
     case UNLOAD:
-      unload_cart(users_table, r->fid->uid);
+      *code = unload_cart(users_table, r->fid->uid);
       break;
   }
   r->ofcall.count = r->ifcall.count;
@@ -189,26 +192,27 @@ }
 }
 
 void read_users(Req* r) {
-  char buf[2113] = {0};
+  String* data = s_new();
   int i;
-  for (i = 0; i < 64; i++) {
+  for (i = 0; i < MAX_USERS; i++) {
     if (scmp(users_table[i].name, r->fid->uid)) {
-      scat(buf, users_table[i].name);
-      ccat(buf, '\n');
+      s_append(data, users_table[i].name);
+      s_putc(data, '\n');
       break;
     }
   }
-  for (i = 0; i < 64; i++) {
+  for (i = 0; i < MAX_USERS; i++) {
     if (
       scmp(users_table[i].name, "\0") ||
       scmp(users_table[i].name, r->fid->uid)) {
       continue;
     }
-    scat(buf, users_table[i].name);
-    ccat(buf, '\n');
+    s_append(data, users_table[i].name);
+    s_putc(data, '\n');
   }
-  ccat(buf, 0);
-  readstr(r, buf);
+  s_terminate(data);
+  readstr(r, data->base);
+  s_free(data);
   respond(r, nil);
 }
 
@@ -250,8 +254,24 @@ }
   free(ss);
 }
 
+void read_ctl(Req* r) {
+  int* code = ctl_code_handle(users_table, r->fid->uid);
+  char buf[8] = {0};
+  if (code != nil) {
+    if (*code) {
+      strcat(buf, "1\n");
+    } else {
+      strcat(buf, "0\n");
+    }
+  } else {
+    strcat(buf, "-1\n");
+  }
+  readstr(r, buf);
+  respond(r, nil);
+}
+
 void read_carts(Req* r) {
-  String** carts = list_dir(CARTSPATH);
+  String** carts = list_dir(DATA_DIR);
   String** c = carts;
   String* data = s_new();
   while (*c != nil) {
@@ -318,7 +338,7 @@ }
 
 void read_realms(Req* r) {
   UserInfo* user = find_user(users_table, r->fid->uid);
-  char realm_path[128] = {0};
+  char realm_path[256] = {0};
   String** realms;
   String** rr;
   Realm* realm;
@@ -346,7 +366,7 @@ realm = parse_realm(user->cart->name, (*rr)->base);
     m = realm->max;
     p = realm->password ? 1 : 0;
 
-    for (i = u = 0; i < 64; i++) {
+    for (i = u = 0; i < MAX_USERS; i++) {
       if (
         users_table[i].realm != nil &&
         scmp(users_table[i].realm->name, realm->name))
@@ -463,22 +483,24 @@ int i;
   int reset = 1;
   int random;
   UserInfo* u = find_user(users_table, r->fid->uid);
-  UserInfo** usrs = malloc(64 * sizeof(UserInfo*));
+  UserInfo** usrs = malloc(MAX_USERS * sizeof(UserInfo*));
   UserInfo* p = users_table;
   UserInfo** uu = usrs;
 
-  if (u->realm == nil)
+  if (u->realm == nil) {
+    respond(r, nil);
     return;
+  }
 
-  for (i = 0; i < 64; i++) {
+  for (i = 0; i < MAX_USERS; i++) {
     if (scmp(p->realm->name, u->realm->name)) {
       *uu++ = p;
-      if (i < 64)
+      if (i < MAX_USERS - 1)
         *uu = nil;
     }
   }
   uu = usrs;
-  for (i = 0; i < 64; i++) {
+  for (i = 0; i < MAX_USERS; i++) {
     if ((*uu) != nil && (*uu)->random >= 0) {
       reset = 0;
       break;
@@ -489,7 +511,7 @@ if (reset) {
     srand(rand());
     random = rand() % 100;
     uu = usrs;
-    for (i = 0; i < 64; i++) {
+    for (i = 0; i < MAX_USERS; i++) {
       if ((*uu) != nil) {
         (*uu)->random = random;
       }
@@ -505,6 +527,9 @@
 void xrxs_read(Req* r) {
   Aux* a = r->fid->file->aux;
   switch (a->type) {
+    case CTL:
+      read_ctl(r);
+      break;
     case USERS:
       read_users(r);
       break;
@@ -586,7 +611,7 @@ fs.tree = alloctree(nil, nil, DMDIR | 0777, fs_destroy_file);
   tree = fs.tree;
 
   closefile(
-    createfile(tree->root, "ctl", nil, DMAPPEND | 0300, create_aux(CTL)));
+    createfile(tree->root, "ctl", nil, DMAPPEND | 0600, create_aux(CTL)));
   closefile(createfile(tree->root, "carts", nil, 0400, create_aux(CARTS)));
   closefile(createfile(tree->root, "users", nil, 0400, create_aux(USERS)));
   closefile(createfile(tree->root, "slot", nil, 0400, create_aux(SLOT)));