server/control.c

   1 /**
   2  * @file control.c
   3  * @brief Handles all client control requests (admin related)
   4  */
   5 #include "common.h"
   6 #include "options.h"
   7 #include "control.h"
   8 #include "sensor.h"
   9 #include "actuator.h"
  10 #include <dirent.h>
  11 #include <sys/types.h>
  12 #include <sys/stat.h>
  13
  14 typedef struct ControlData {
  15         ControlModes current_mode;
  16         pthread_mutex_t mutex;
  17         struct timespec start_time;
  18         char user_name[31]; // The user who owns the currently running experiment
  19         char experiment_dir[BUFSIZ]; //Directory for experiment
  20         char experiment_name[BUFSIZ];
  21 } ControlData;
  22
  23 ControlData g_controls = {CONTROL_STOP, PTHREAD_MUTEX_INITIALIZER, {0}};
  24
  25 bool DirExists(const char *path)
  26 {
  27         DIR *dir = opendir(path);
  28         if (dir) {
  29                 closedir(dir);
  30                 return true;
  31         }
  32         return false;
  33 }
  34
  35 bool PathExists(const char *path)
  36 {
  37         FILE *fp = fopen(path, "r");
  38         if (fp) {
  39                 fclose(fp);
  40                 return true;
  41         }
  42         return false;
  43 }
  44
  45 /**
  46  * Lists all experiments for the current user.
  47  * @param The context to work in
  48  */
  49 void ListExperiments(FCGIContext *context)
  50 {
  51         DIR * dir = opendir(context->user_dir);
  52         if (dir == NULL)
  53         {
  54                 FCGI_RejectJSON(context, "Failed to open user directory");
  55                 return;
  56         }
  57         struct dirent * ent;
  58         FCGI_BeginJSON(context, STATUS_OK);
  59         FCGI_JSONKey("experiments");
  60         FCGI_PrintRaw("[");
  61
  62         bool first = true;
  63         while ((ent = readdir(dir)) != NULL) {
  64                 char *ext = strrchr(ent->d_name, '.');
  65                 if (ext && !strcmp(ext, ".exp")) {
  66                         if (!first) {
  67                                 FCGI_PrintRaw(", ");
  68                         }
  69
  70                         *ext = '\0'; // Ummm... probably not a great idea
  71                         FCGI_PrintRaw("\"%s\"", ent->d_name);
  72                         first = false;
  73                 }
  74         }
  75         FCGI_PrintRaw("]");
  76         FCGI_EndJSON();
  77
  78         closedir(dir);
  79         return;
  80 }
  81
  82 /**
  83  * System control handler. This covers high-level control, including
  84  * admin related functions and starting/stopping experiments..
  85  * @param context The context to work in
  86  * @param params The input parameters
  87  */
  88 void Control_Handler(FCGIContext *context, char *params) {
  89         const char *action = "";
  90         const char *name = "";
  91         bool force = false;
  92         ControlModes desired_mode;
  93
  94         // Login/auth now handled entirely in fastcgi.c and login.c
  95         //TODO: Need to not have the ability for any user to stop someone else' experiment...
  96         // (achieve by storing the username of the person running the current experiment, even when they log out?)
  97         // (Our program should only realisitically support a single experiment at a time, so that should be sufficient)
  98         FCGIValue values[3] = {
  99                 {"action", &action, FCGI_REQUIRED(FCGI_STRING_T)},
 100                 {"force", &force, FCGI_BOOL_T},
 101                 {"name", &name, FCGI_STRING_T}
 102         };
 103
 104         if (!FCGI_ParseRequest(context, params, values, 3))
 105                 return;
 106
 107         if (!strcmp(action, "identify")) {
 108                 FCGI_BeginJSON(context, STATUS_OK);
 109                 FCGI_JSONLong("control_state_id", g_controls.current_mode);
 110                 FCGI_JSONPair("control_user_name", g_controls.user_name);
 111                 FCGI_JSONPair("control_experiment_name", g_controls.experiment_name);
 112                 FCGI_EndJSON();
 113                 return;
 114         } else if (!strcmp(action, "list")) {
 115                 ListExperiments(context);
 116                 return;
 117         }
 118         //TODO: Need a "load" action to set data files (but not run) from a past experiment
 119
 120         //TODO: Need a "delete" action so that people can overwrite experiments (without all this "force" shenanigans)
 121
 122         if (!strcmp(action, "emergency")) {
 123                 desired_mode = CONTROL_EMERGENCY;
 124         } else if (!strcmp(action, "start")) {
 125                 desired_mode = CONTROL_START;
 126         } else if (!strcmp(action, "pause")) {
 127                 desired_mode = CONTROL_PAUSE;
 128         } else if (!strcmp(action, "resume")) {
 129                 desired_mode = CONTROL_RESUME;
 130         } else if (!strcmp(action, "stop")) {
 131                 desired_mode = CONTROL_STOP;
 132         } else {
 133                 FCGI_RejectJSON(context, "Unknown action specified.");
 134                 return;
 135         }
 136
 137         if ((*g_controls.user_name) != '\0' && strcmp(g_controls.user_name, context->user_name) != 0)
 138         {
 139                 if (context->user_type != USER_ADMIN) {
 140                         FCGI_RejectJSON(context, "Another user has an experiment in progress.");
 141                         return;
 142                 }
 143
 144                 if (!force) {
 145                         Log(LOGERR, "User %s is currently running an experiment!", g_controls.user_name);
 146                         FCGI_RejectJSON(context, "Pass \"force\" to take control over another user's experiment");
 147                         return;
 148                 }
 149         }
 150
 151         void *arg = NULL;
 152         char experiment_dir[BUFSIZ] = {0};
 153         if (desired_mode == CONTROL_START) {
 154                 int ret;
 155
 156                 if (*name == '\0') {
 157                         FCGI_RejectJSON(context, "An experiment name must be specified.");
 158                         return;
 159                 } if (strpbrk(name, INVALID_CHARACTERS)) {
 160                         FCGI_RejectJSON(context,
 161                                 "An experiment name must not contain: " INVALID_CHARACTERS_JSON);
 162                         return;
 163                 }
 164
 165                 if (*(context->user_dir) == '\0') {
 166                         FCGI_RejectJSON(context, "Not creating experiment in root dir.");
 167                         return;
 168                 }
 169
 170                 ret = snprintf(experiment_dir, BUFSIZ, "%s/%s.exp",
 171                                                 context->user_dir, name);
 172                 if (ret >= BUFSIZ) {
 173                         FCGI_RejectJSON(context, "The experiment name is too long.");
 174                         return;
 175                 } else if (DirExists(experiment_dir) && !force) {
 176                         FCGI_RejectJSON(context, "An experiment with that name already exists.");
 177                         return;
 178                 }
 179
 180                 arg = (void*) experiment_dir;
 181         }
 182
 183         const char *ret;
 184         if ((ret = Control_SetMode(desired_mode, arg)) != NULL) {
 185                 FCGI_RejectJSON(context, ret);
 186         } else {
 187                 if (desired_mode == CONTROL_STOP) {
 188                         g_controls.user_name[0] = '\0';
 189                         g_controls.experiment_dir[0] = '\0';
 190                         g_controls.experiment_name[0] = '\0';
 191                 } else if (desired_mode == CONTROL_START) {
 192                         snprintf(g_controls.user_name, sizeof(g_controls.user_name),
 193                                                 "%s", context->user_name);
 194                         snprintf(g_controls.experiment_dir, sizeof(g_controls.experiment_dir),
 195                                                 "%s", experiment_dir);
 196                         snprintf(g_controls.experiment_name, sizeof(g_controls.experiment_name),
 197                                                 "%s", name);
 198                 }
 199
 200                 FCGI_AcceptJSON(context, "Ok");
 201         }
 202 }
 203
 204 /**
 205  * Sets the mode to the desired mode, if possible.
 206  * @param desired_mode The mode to be set to
 207  * @param arg An argument specific to the mode to be set.
 208  * @return NULL on success, an error message on failure.
 209  */
 210 const char* Control_SetMode(ControlModes desired_mode, void * arg)
 211 {
 212         const char *ret = NULL;
 213
 214         pthread_mutex_lock(&(g_controls.mutex));
 215         if (g_controls.current_mode == desired_mode)
 216                 ret = "Already in the desired mode.";
 217         else if (g_controls.current_mode == CONTROL_EMERGENCY && desired_mode != CONTROL_STOP)
 218                 ret = "In emergency mode. You must stop before continuing.";
 219         else switch (desired_mode) {
 220                 case CONTROL_START:
 221                         if (g_controls.current_mode == CONTROL_STOP) {
 222                                 const char * path = arg;
 223                                 if (mkdir(path, 0777) != 0 && errno != EEXIST) {
 224                                         Log(LOGERR, "Couldn't create experiment directory %s - %s",
 225                                                 path, strerror(errno));
 226                                         ret = "Couldn't create experiment directory.";
 227                                 } else {
 228                                         clock_gettime(CLOCK_MONOTONIC, &(g_controls.start_time));
 229                                 }
 230                         } else
 231                                 ret = "Cannot start when not in a stopped state.";
 232                 break;
 233                 case CONTROL_PAUSE:
 234                         if (g_controls.current_mode != CONTROL_START)
 235                                 ret = "Cannot pause when not in a running state.";
 236                 break;
 237                 case CONTROL_RESUME:
 238                         if (g_controls.current_mode != CONTROL_PAUSE)
 239                                 ret = "Cannot resume when not in a paused state.";
 240                 break;
 241                 case CONTROL_EMERGENCY:
 242                         if (g_controls.current_mode != CONTROL_START) //pfft
 243                                 ret = "Not running so how can there be an emergency?";
 244                 break;
 245                 default:
 246                 break;
 247         }
 248
 249         if (ret == NULL) {
 250                 Actuator_SetModeAll(desired_mode, arg);
 251                 Sensor_SetModeAll(desired_mode, arg);
 252                 if (desired_mode != CONTROL_RESUME)
 253                         g_controls.current_mode = desired_mode;
 254                 else
 255                         g_controls.current_mode = CONTROL_START;
 256         }
 257         pthread_mutex_unlock(&(g_controls.mutex));
 258         return ret;
 259 }
 260
 261 /**
 262  * Gets a string representation of the current mode
 263  * @param mode The mode to get a string representation of
 264  * @return The string representation of the mode
 265  */
 266 const char * Control_GetModeName() {
 267         const char * ret = "Unknown";
 268
 269         switch (g_controls.current_mode) {
 270                 case CONTROL_START: ret = "Running"; break;
 271                 case CONTROL_PAUSE: ret = "Paused"; break;
 272                 case CONTROL_RESUME: ret = "Resumed"; break;
 273                 case CONTROL_STOP: ret = "Stopped"; break;
 274                 case CONTROL_EMERGENCY: ret = "Emergency mode"; break;
 275         }
 276         return ret;
 277 }
 278
 279 /**
 280  * Gets the start time for the current experiment
 281  * @return the start time
 282  */
 283 const struct timespec * Control_GetStartTime() {
 284         return &g_controls.start_time;
 285 }