Add internal min/max/next id management fucntions

Retrieve minID and maxID from domain configuration so that lower
and upper bounds can be set per domain.

Add function that keeps track of the next available id, increments
and returns it on requests, avoiding collisions with existing ids.

3 files changed, 290 insertions, 14 deletions

diff --git a/server/db/sysdb.c b/server/db/sysdb.c
index b6558499..bdc7588f 100644
--- a/server/db/sysdb.c
+++ b/server/db/sysdb.c
@@ -36,6 +36,12 @@ struct ldb_dn *sysdb_group_dn(struct sysdb_ctx *ctx, void *memctx,
     return ldb_dn_new_fmt(memctx, ctx->ldb, SYSDB_TMPL_GROUP, name, domain);
 }
 
+struct ldb_dn *sysdb_domain_dn(struct sysdb_ctx *ctx, void *memctx,
+                              const char *domain)
+{
+    return ldb_dn_new_fmt(memctx, ctx->ldb, SYSDB_DOM_BASE, domain);
+}
+
 struct ldb_context *sysdb_ctx_get_ldb(struct sysdb_ctx *ctx)
 {
     return ctx->ldb;
diff --git a/server/db/sysdb.h b/server/db/sysdb.h
index c1ae7979..4083edd8 100644
--- a/server/db/sysdb.h
+++ b/server/db/sysdb.h
@@ -36,6 +36,10 @@
 #define SYSDB_USER_CLASS "user"
 #define SYSDB_GROUP_CLASS "group"
 
+#define SYSDB_NEXTID "nextID"
+#define SYSDB_UIDNUM "uidNumber"
+#define SYSDB_GIDNUM "gidNumber"
+
 #define SYSDB_PW_NAME "uid"
 #define SYSDB_PW_PWD "userPassword"
 #define SYSDB_PW_UIDNUM "uidNumber"
@@ -64,6 +68,8 @@
 
 #define SYSDB_LAST_UPDATE "lastUpdate"
 
+#define SYSDB_NEXTID_FILTER "("SYSDB_NEXTID"=*)"
+
 #define SYSDB_PWNAM_FILTER "(&(objectclass="SYSDB_USER_CLASS")("SYSDB_PW_NAME"=%s))"
 #define SYSDB_PWUID_FILTER "(&(objectclass="SYSDB_USER_CLASS")("SYSDB_PW_UIDNUM"=%lu))"
 #define SYSDB_PWENT_FILTER "(objectclass="SYSDB_USER_CLASS")"
@@ -160,9 +166,10 @@ void sysdb_operation_done(struct sysdb_req *req);
 
 struct ldb_dn *sysdb_user_dn(struct sysdb_ctx *ctx, void *memctx,
                              const char *domain, const char *name);
-
 struct ldb_dn *sysdb_group_dn(struct sysdb_ctx *ctx, void *memctx,
                               const char *domain, const char *name);
+struct ldb_dn *sysdb_domain_dn(struct sysdb_ctx *ctx, void *memctx,
+                               const char *domain);
 
 int sysdb_init(TALLOC_CTX *mem_ctx,
                struct tevent_context *ev,
diff --git a/server/db/sysdb_ops.c b/server/db/sysdb_ops.c
index 3a51f435..8e3eb4fa 100644
--- a/server/db/sysdb_ops.c
+++ b/server/db/sysdb_ops.c
@@ -50,6 +50,28 @@ static int add_ulong(struct ldb_message *msg, int flags,
     return ret;
 }
 
+static uint32_t get_attr_as_uint32(struct ldb_message *msg, const char *attr)
+{
+    const struct ldb_val *v = ldb_msg_find_ldb_val(msg, attr);
+    long long int l;
+
+    if (!v || !v->data) {
+        return 0;
+    }
+
+    errno = 0;
+    l = strtoll((const char *)v->data, NULL, 0);
+    if (errno) {
+        return (uint32_t)-1;
+    }
+
+    if (l < 0 || l > ((uint32_t)(-1))) {
+        return (uint32_t)-1;
+    }
+
+    return l;
+}
+
 /* the following are all SYNCHRONOUS calls
  * TODO: make these asynchronous */
 
@@ -268,19 +290,22 @@ static int delete_callback(struct ldb_request *req, struct ldb_reply *rep)
 
     switch (rep->type) {
     case LDB_REPLY_ENTRY:
-        res->msgs = talloc_realloc(res, res->msgs,
-                                   struct ldb_message *,
-                                   res->count + 2);
+        if (res->msgs != NULL) {
+            DEBUG(1, ("More than one reply for a base search ?! "
+                      "DB seems corrupted, aborting."));
+            return_error(cbctx, EFAULT);
+            return LDB_ERR_OPERATIONS_ERROR;
+        }
+        res->msgs = talloc_realloc(res, res->msgs, struct ldb_message *, 2);
         if (!res->msgs) {
             ret = LDB_ERR_OPERATIONS_ERROR;
             return_error(cbctx, sysdb_error_to_errno(ret));
             return ret;
         }
 
-        res->msgs[res->count + 1] = NULL;
-
-        res->msgs[res->count] = talloc_steal(res->msgs, rep->message);
-        res->count++;
+        res->msgs[0] = talloc_steal(res->msgs, rep->message);
+        res->msgs[1] = NULL;
+        res->count = 1;
 
         break;
 
@@ -291,12 +316,6 @@ static int delete_callback(struct ldb_request *req, struct ldb_reply *rep)
             return_done(cbctx);
             break;
         }
-        if (res->count > 1) {
-            DEBUG(0, ("Cache DB corrupted, base search returned %d results\n",
-                      res->count));
-            return_error(cbctx, EFAULT);
-            return LDB_ERR_OPERATIONS_ERROR;
-        }
 
         dn = ldb_dn_copy(del_ctx, res->msgs[0]->dn);
         if (!dn) {
@@ -490,6 +509,250 @@ int sysdb_set_user_attr(struct sysdb_req *sysreq,
     return EOK;
 }
 
+struct next_id {
+    uint32_t id;
+};
+
+struct next_id_ctx {
+    struct sysdb_req *sysreq;
+    struct sss_domain_info *domain;
+    struct sysdb_cb_ctx *cbctx;
+
+    struct ldb_dn *base_dn;
+	struct ldb_result *res;
+    uint32_t tmp_id;
+
+    enum next_step { NEXTID_SEARCH=0, NEXTID_VERIFY, NEXTID_STORE } step;
+
+    struct next_id *result;
+};
+
+static int nextid_callback(struct ldb_request *req, struct ldb_reply *rep);
+
+static int sysdb_get_next_available_id(struct sysdb_req *sysreq,
+                                       struct sss_domain_info *domain,
+                                       struct next_id *result,
+                                       sysdb_callback_t fn, void *pvt)
+{
+    static const char *attrs[] = { SYSDB_NEXTID, NULL };
+    struct sysdb_ctx *ctx;
+    struct next_id_ctx *idctx;
+    struct ldb_request *req;
+    int ret;
+
+    if (!sysdb_req_check_running(sysreq)) {
+        DEBUG(2, ("Invalid request! Not running at this time.\n"));
+        return EINVAL;
+    }
+
+    ctx = sysdb_req_get_ctx(sysreq);
+
+    idctx = talloc_zero(sysreq, struct next_id_ctx);
+    if (!idctx) return ENOMEM;
+
+    idctx->domain = domain;
+    idctx->result = result;
+
+    idctx->cbctx = talloc_zero(sysreq, struct sysdb_cb_ctx);
+    if (!idctx->cbctx) return ENOMEM;
+
+    idctx->cbctx->fn = fn;
+    idctx->cbctx->pvt = pvt;
+
+    idctx->base_dn = sysdb_domain_dn(ctx, idctx, domain->name);
+    if (!idctx->base_dn) return ENOMEM;
+
+    idctx->res = talloc_zero(idctx, struct ldb_result);
+    if (!idctx->res) return ENOMEM;
+
+    ret = ldb_build_search_req(&req, ctx->ldb, idctx,
+                               idctx->base_dn, LDB_SCOPE_BASE,
+                               SYSDB_NEXTID_FILTER, attrs, NULL,
+                               idctx, nextid_callback, NULL);
+    if (ret != LDB_SUCCESS) {
+        DEBUG(1, ("Failed to build search request: %s(%d)[%s]\n",
+                  ldb_strerror(ret), ret, ldb_errstring(ctx->ldb)));
+        return sysdb_error_to_errno(ret);
+    }
+
+    ret = ldb_request(ctx->ldb, req);
+    if (ret != LDB_SUCCESS) return sysdb_error_to_errno(ret);
+
+    return EOK;
+}
+
+static int nextid_callback(struct ldb_request *req, struct ldb_reply *rep)
+{
+    static const char *attrs[] = { SYSDB_UIDNUM, SYSDB_GIDNUM, NULL };
+    struct next_id_ctx *idctx;
+    struct sysdb_cb_ctx *cbctx;
+    struct sysdb_ctx *ctx;
+    struct ldb_request *nreq;
+    struct ldb_message *msg;
+    struct ldb_result *res;
+    char *filter;
+    int ret;
+
+    idctx = talloc_get_type(req->context, struct next_id_ctx);
+    ctx = sysdb_req_get_ctx(idctx->sysreq);
+    cbctx = idctx->cbctx;
+    res = idctx->res;
+
+    if (!rep) {
+        return_error(cbctx, EIO);
+        return LDB_ERR_OPERATIONS_ERROR;
+    }
+    if (rep->error != LDB_SUCCESS) {
+        return_error(cbctx, sysdb_error_to_errno(rep->error));
+        return rep->error;
+    }
+
+    switch (rep->type) {
+    case LDB_REPLY_ENTRY:
+
+        if (idctx->step == NEXTID_VERIFY) {
+            res->count++;
+            break;
+        }
+
+        /* NEXTID_SEARCH */
+        if (res->msgs != NULL) {
+            DEBUG(1, ("More than one reply for a base search ?! "
+                      "DB seems corrupted, aborting."));
+            return_error(cbctx, EFAULT);
+            return LDB_ERR_OPERATIONS_ERROR;
+        }
+
+        res->msgs = talloc_realloc(res, res->msgs, struct ldb_message *, 2);
+        if (!res->msgs) {
+            ret = LDB_ERR_OPERATIONS_ERROR;
+            return_error(cbctx, sysdb_error_to_errno(ret));
+            return ret;
+        }
+
+        res->msgs[0] = talloc_steal(res->msgs, rep->message);
+        res->msgs[1] = NULL;
+        res->count = 1;
+
+        break;
+
+    case LDB_REPLY_DONE:
+
+        switch (idctx->step) {
+        case NEXTID_SEARCH:
+            if (res->count == 0) {
+                DEBUG(4, ("Base search returned no results\n"));
+                return_done(cbctx);
+                break;
+            }
+
+            idctx->tmp_id = get_attr_as_uint32(res->msgs[0], SYSDB_NEXTID);
+            if (idctx->tmp_id == (uint32_t)(-1)) {
+                DEBUG(1, ("Invalid Next ID in domain %s\n",
+                          idctx->domain->name));
+                return_error(cbctx, ERANGE);
+                return LDB_ERR_OPERATIONS_ERROR;
+            }
+
+            if (idctx->tmp_id < idctx->domain->id_min) {
+                DEBUG(2, ("Initializing domain next id to id min %u\n",
+                          idctx->domain->id_min));
+            }
+            if ((idctx->domain->id_max != 0) &&
+                (idctx->tmp_id > idctx->domain->id_max)) {
+                DEBUG(0, ("Failed to allocate new id, out of range (%u/%u)\n",
+                          idctx->tmp_id, idctx->domain->id_max));
+                return_error(cbctx, ERANGE);
+                return LDB_ERR_OPERATIONS_ERROR;
+            }
+
+            talloc_free(res->msgs);
+            res->msgs = NULL;
+
+            idctx->step = NEXTID_VERIFY;
+
+        case NEXTID_VERIFY:
+            if (res->count) {
+                /* actually something's using the id, try next */
+                idctx->tmp_id++;
+            } else {
+                /* ok store new next_id */
+                idctx->result->id = idctx->tmp_id;
+                idctx->tmp_id++;
+                idctx->step = NEXTID_STORE;
+            }
+
+        default:
+            DEBUG(1, ("Invalid step, aborting.\n"));
+            return_error(cbctx, EFAULT);
+            return LDB_ERR_OPERATIONS_ERROR;
+        }
+
+        switch (idctx->step) {
+        case NEXTID_VERIFY:
+            filter = talloc_asprintf(idctx, "(|(%s=%u)(%s=%u))",
+                                     SYSDB_UIDNUM, idctx->tmp_id,
+                                     SYSDB_GIDNUM, idctx->tmp_id);
+            if (!filter) {
+                return_error(cbctx, ENOMEM);
+                return LDB_ERR_OPERATIONS_ERROR;
+            }
+            ret = ldb_build_search_req(&nreq, ctx->ldb, idctx,
+                                       idctx->base_dn, LDB_SCOPE_SUBTREE,
+                                       filter, attrs, NULL,
+                                       idctx, nextid_callback, NULL);
+            break;
+
+        case NEXTID_STORE:
+            msg = ldb_msg_new(idctx);
+            if (!msg) {
+                return_error(cbctx, ENOMEM);
+                return LDB_ERR_OPERATIONS_ERROR;
+            }
+
+            msg->dn = idctx->base_dn;
+
+            ret = add_ulong(msg, LDB_FLAG_MOD_REPLACE,
+                            SYSDB_NEXTID, idctx->tmp_id);
+            if (ret != LDB_SUCCESS) {
+                return_error(cbctx, ENOMEM);
+                return LDB_ERR_OPERATIONS_ERROR;
+            }
+
+            ret = ldb_build_mod_req(&nreq, ctx->ldb, idctx, msg, NULL,
+                                    idctx, sysdb_op_callback, NULL);
+            break;
+
+        default:
+            DEBUG(1, ("Invalid step, aborting.\n"));
+            return_error(cbctx, EFAULT);
+            return LDB_ERR_OPERATIONS_ERROR;
+        }
+
+        if (ret != LDB_SUCCESS) {
+            DEBUG(1, ("Failed to build search request: %s(%d)[%s]\n",
+                      ldb_strerror(ret), ret, ldb_errstring(ctx->ldb)));
+            return_error(cbctx, sysdb_error_to_errno(ret));
+            return LDB_ERR_OPERATIONS_ERROR;
+        }
+
+        ret = ldb_request(ctx->ldb, nreq);
+        if (ret != LDB_SUCCESS) {
+            return_error(cbctx, sysdb_error_to_errno(ret));
+            return LDB_ERR_OPERATIONS_ERROR;
+        }
+
+        break;
+
+    default:
+        return_error(cbctx, EINVAL);
+        return LDB_ERR_OPERATIONS_ERROR;
+    }
+
+    talloc_free(rep);
+    return LDB_SUCCESS;
+}
+