Support a per-location nice value. Note that since we now have two different settings
in the per-dir configuration, we need to introduce a merge function.

Index: httpd-2.4.1/server/mpm/itk/itk.c
===================================================================
--- httpd-2.4.1.orig/server/mpm/itk/itk.c
+++ httpd-2.4.1/server/mpm/itk/itk.c
@@ -165,11 +165,14 @@ static pid_t ap_my_pid; /* it seems sill
 static pid_t parent_pid;
 static int my_child_num;
 
+#define UNSET_NICE_VALUE 100
+
 typedef struct
 {
     uid_t uid;
     gid_t gid;
     char *username;
+    int nice_value;
 } itk_per_dir_conf;
 
 typedef struct
@@ -532,6 +535,7 @@ static void child_main(int child_num_arg
         CAP_SETUID,
         CAP_SETGID,
         CAP_DAC_READ_SEARCH,
+        CAP_SYS_NICE,
     };
 #endif    
 
@@ -1554,6 +1558,12 @@ static int itk_post_perdir_config(reques
     strncpy(ap_scoreboard_image->servers[my_child_num][0].vhost, r->server->server_hostname, 31);
     ap_scoreboard_image->servers[my_child_num][0].vhost[31] = 0;
 
+    if (dconf->nice_value != UNSET_NICE_VALUE &&
+        setpriority(PRIO_PROCESS, 0, dconf->nice_value)) {
+        _DBG("setpriority(): %s", strerror(errno));
+        err = 1;
+    }
+
     wanted_uid = dconf->uid;
     wanted_gid = dconf->gid;
     wanted_username = dconf->username;
@@ -1564,7 +1574,7 @@ static int itk_post_perdir_config(reques
         wanted_username = ap_unixd_config.user_name;
     }
 
-    if (wanted_uid != -1 && wanted_gid != -1 && (getuid() != wanted_uid || getgid() != wanted_gid)) {
+    if (!err && wanted_uid != -1 && wanted_gid != -1 && (getuid() != wanted_uid || getgid() != wanted_gid)) {
         if (setgid(wanted_gid)) {
             _DBG("setgid(%d): %s", wanted_gid, strerror(errno));
             err = 1;
@@ -1584,7 +1594,7 @@ static int itk_post_perdir_config(reques
      */
     if (err) {
         ap_log_error(APLOG_MARK, APLOG_WARNING, 0, NULL, \
-            "Couldn't set uid/gid, closing connection.");
+            "Couldn't set uid/gid/priority, closing connection.");
         ap_lingering_close(r->connection);
         exit(0);
     }
@@ -1695,6 +1705,27 @@ static const char *set_max_clients_vhost
     return NULL;
 }
 
+static const char *set_nice_value (cmd_parms *cmd, void *ptr, const char *arg)
+{
+    itk_per_dir_conf *dconf = (itk_per_dir_conf *) ptr;
+    int nice_value = atoi(arg);
+
+    if (nice_value < -20) {
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                     "WARNING: NiceValue of %d is below -20, increasing NiceValue to -20.",
+                     nice_value);
+        nice_value = -20;
+    }
+    else if (nice_value > 19) {
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                     "WARNING: NiceValue of %d is above 19, lowering NiceValue to 19.",
+                     nice_value);
+        nice_value = 19;
+    }
+    dconf->nice_value = nice_value;
+    return NULL;
+}
+
 static const command_rec itk_cmds[] = {
 LISTEN_COMMANDS,
 AP_INIT_TAKE1("StartServers", set_daemons_to_start, NULL, RSRC_CONF,
@@ -1713,6 +1744,8 @@ AP_INIT_TAKE2("AssignUserID", assign_use
               "Tie a virtual host to a specific child process."),
 AP_INIT_TAKE1("MaxClientsVHost", set_max_clients_vhost, NULL, RSRC_CONF,
               "Maximum number of children alive at the same time for this virtual host."),
+AP_INIT_TAKE1("NiceValue", set_nice_value, NULL, RSRC_CONF|ACCESS_CONF,
+              "Set nice value for the given vhost, from -20 (highest priority) to 19 (lowest priority)."),
 AP_GRACEFUL_SHUTDOWN_TIMEOUT_COMMAND,
 { NULL }
 };
@@ -1723,6 +1756,32 @@ static void *itk_create_dir_config(apr_p
     itk_per_dir_conf *c = (itk_per_dir_conf *)
         apr_pcalloc(p, sizeof(itk_per_dir_conf));
     c->uid = c->gid = -1;
+    c->nice_value = UNSET_NICE_VALUE;
+    return c;
+}
+
+/* == merge the parent per-dir config structure into ours == */
+static void *itk_merge_dir_config(apr_pool_t *p, void *parent_ptr, void *child_ptr)
+{
+    itk_per_dir_conf *c = (itk_per_dir_conf *)
+        itk_create_dir_config(p, NULL);
+    itk_per_dir_conf *parent = (itk_per_dir_conf *) parent_ptr;
+    itk_per_dir_conf *child = (itk_per_dir_conf *) child_ptr;
+
+    if (child->username != NULL) {
+      c->username = child->username;
+      c->uid = child->uid;
+      c->gid = child->gid;
+    } else {
+      c->username = parent->username;
+      c->uid = parent->uid;
+      c->gid = parent->gid;
+    }
+    if (child->nice_value != UNSET_NICE_VALUE) {
+      c->nice_value = child->nice_value;
+    } else {
+      c->nice_value = parent->nice_value;
+    }
     return c;
 }
 
@@ -1739,7 +1798,7 @@ AP_DECLARE_MODULE(mpm_itk) = {
     MPM20_MODULE_STUFF,
     NULL,                       /* hook to run before apache parses args */
     itk_create_dir_config,      /* create per-directory config structure */
-    NULL,                       /* merge per-directory config structures */
+    itk_merge_dir_config,       /* merge per-directory config structures */
     itk_create_server_config,   /* create per-server config structure */
     NULL,                       /* merge per-server config structures */
     itk_cmds,                   /* command apr_table_t */