ltt-sessiond/traceable-app.c

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <errno.h>
  21 #include <pthread.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <urcu/list.h>
  25
  26 #include "lttngerr.h"
  27 #include "traceable-app.h"
  28
  29 /* Number of element for the list below. */
  30 static unsigned int traceable_app_count;
  31
  32 /* Init ust traceabl application's list */
  33 struct ltt_traceable_app_list ltt_traceable_app_list = {
  34         .head = CDS_LIST_HEAD_INIT(ltt_traceable_app_list.head),
  35 };
  36
  37 /* List mutex */
  38 pthread_mutex_t ltt_traceable_app_list_mutex;
  39
  40 /* Internal function */
  41 static void add_traceable_app(struct ltt_traceable_app *lta);
  42 static void del_traceable_app(struct ltt_traceable_app *lta);
  43
  44 /*
  45  *  add_traceable_app
  46  *
  47  *  Add a traceable application structure to the global
  48  *  list protected by a mutex.
  49  */
  50 static void add_traceable_app(struct ltt_traceable_app *lta)
  51 {
  52         pthread_mutex_lock(&ltt_traceable_app_list_mutex);
  53         cds_list_add(&lta->list, &ltt_traceable_app_list.head);
  54         traceable_app_count++;
  55         pthread_mutex_unlock(&ltt_traceable_app_list_mutex);
  56 }
  57
  58 /*
  59  *  del_traceable_app
  60  *
  61  *  Delete a traceable application structure from the
  62  *  global list protected by a mutex.
  63  */
  64 static void del_traceable_app(struct ltt_traceable_app *lta)
  65 {
  66         pthread_mutex_lock(&ltt_traceable_app_list_mutex);
  67         cds_list_del(&lta->list);
  68         /* Sanity check */
  69         if (traceable_app_count != 0) {
  70                 traceable_app_count--;
  71         }
  72         pthread_mutex_unlock(&ltt_traceable_app_list_mutex);
  73 }
  74
  75 /*
  76  *  register_traceable_app
  77  *
  78  *  Using pid and uid (of the app), allocate
  79  *  a new ltt_traceable_app struct and add it
  80  *  to the global traceable app list.
  81  *
  82  *  On success, return 0, else return malloc ENOMEM.
  83  */
  84 int register_traceable_app(pid_t pid, uid_t uid)
  85 {
  86         struct ltt_traceable_app *lta;
  87
  88         lta = malloc(sizeof(struct ltt_traceable_app));
  89         if (lta == NULL) {
  90                 perror("malloc");
  91                 return -ENOMEM;
  92         }
  93
  94         lta->uid = uid;
  95         lta->pid = pid;
  96         add_traceable_app(lta);
  97         DBG("Application %d registered with UID %d", pid, uid);
  98
  99         return 0;
 100 }
 101
 102 /*
 103  *  unregister_traceable_app
 104  *
 105  *  Unregister app by removing it from the global
 106  *  traceable app list and freeing the data struct.
 107  */
 108 void unregister_traceable_app(pid_t pid)
 109 {
 110         struct ltt_traceable_app *lta;
 111
 112         lta = find_app_by_pid(pid);
 113         if (lta != NULL) {
 114                 del_traceable_app(lta);
 115                 free(lta);
 116                 DBG("PID %d unregistered", pid);
 117         }
 118 }
 119
 120 /*
 121  *  get_app_count
 122  *
 123  *  Return traceable_app_count
 124  */
 125 unsigned int get_app_count(void)
 126 {
 127         return traceable_app_count;
 128 }
 129
 130 /*
 131  *  find_app_by_pid
 132  *
 133  *  Iterate over the traceable apps list and
 134  *  return a pointer or NULL if not found.
 135  */
 136 struct ltt_traceable_app *find_app_by_pid(pid_t pid)
 137 {
 138         struct ltt_traceable_app *iter;
 139
 140         pthread_mutex_lock(&ltt_traceable_app_list_mutex);
 141         cds_list_for_each_entry(iter, &ltt_traceable_app_list.head, list) {
 142                 if (iter->pid == pid) {
 143                         pthread_mutex_unlock(&ltt_traceable_app_list_mutex);
 144                         /* Found */
 145                         return iter;
 146                 }
 147         }
 148         pthread_mutex_unlock(&ltt_traceable_app_list_mutex);
 149
 150         return NULL;
 151 }
 152
 153 /*
 154  *      get_app_list_pids
 155  *
 156  *  List traceable user-space application and fill an
 157  *  array of pids.
 158  */
 159 void get_app_list_pids(pid_t *pids)
 160 {
 161         int i = 0;
 162         struct ltt_traceable_app *iter;
 163
 164         /* Protected by a mutex here because the threads manage_client
 165          * and manage_apps can access this list.
 166          */
 167         pthread_mutex_lock(&ltt_traceable_app_list_mutex);
 168         cds_list_for_each_entry(iter, &ltt_traceable_app_list.head, list) {
 169                 pids[i] = iter->pid;
 170                 i++;
 171         }
 172         pthread_mutex_unlock(&ltt_traceable_app_list_mutex);
 173 }