server/control.c

   1 /**
   2  * @file control.c
   3  * @brief Handles all client control requests (admin related)
   4  */
   5 #include "common.h"
   6 #include "control.h"
   7 #include "sensor.h"
   8 #include "actuator.h"
   9
  10 typedef struct ControlData {
  11         ControlModes current_mode;
  12         pthread_mutex_t mutex;
  13         struct timeval start_time;
  14 } ControlData;
  15
  16 ControlData g_controls = {CONTROL_STOP, PTHREAD_MUTEX_INITIALIZER, {0}};
  17
  18 static bool PathExists(const char *path) {
  19         FILE *fp = fopen(path, "r");
  20         if (fp) {
  21                 fclose(fp);
  22                 return true;
  23         }
  24         return false;
  25 }
  26
  27 /**
  28  * System control handler. This covers high-level control, including
  29  * admin related functions and starting/stopping experiments..
  30  * @param context The context to work in
  31  * @param params The input parameters
  32  */
  33 void Control_Handler(FCGIContext *context, char *params) {
  34         const char *action, *key = "", *name = "";
  35         bool force = false;
  36         ControlModes desired_mode;
  37
  38         FCGIValue values[4] = {
  39                 {"action", &action, FCGI_REQUIRED(FCGI_STRING_T)},
  40                 {"key", &key, FCGI_STRING_T},
  41                 {"force", &force, FCGI_BOOL_T},
  42                 {"name", &name, FCGI_STRING_T}
  43         };
  44
  45         if (!FCGI_ParseRequest(context, params, values, 4))
  46                 return;
  47
  48         if (!strcmp(action, "lock")) {
  49                 FCGI_LockControl(context, force);
  50                 return;
  51         } else if (!strcmp(action, "emergency")) {
  52                 desired_mode = CONTROL_EMERGENCY;
  53         } else if (FCGI_HasControl(context, key)) {
  54                 if (!strcmp(action, "release")) {
  55                         FCGI_ReleaseControl(context);
  56                 } else if (!strcmp(action, "start")) {
  57                         desired_mode = CONTROL_START;
  58                 } else if (!strcmp(action, "pause")) {
  59                         desired_mode = CONTROL_PAUSE;
  60                 } else if (!strcmp(action, "resume")) {
  61                         desired_mode = CONTROL_RESUME;
  62                 } else if (!strcmp(action, "stop")) {
  63                         desired_mode = CONTROL_STOP;
  64                 } else {
  65                         FCGI_RejectJSON(context, "Unknown action specified.");
  66                         return;
  67                 }
  68         } else {
  69                 FCGI_RejectJSONEx(context, STATUS_UNAUTHORIZED,
  70                         "Invalid control key specified.");
  71                 return;
  72         }
  73
  74         void *arg = NULL;
  75         if (desired_mode == CONTROL_START) {
  76                 if (PathExists(name) && !force) {
  77                         FCGI_RejectJSON(context, "An experiment with that name already exists.");
  78                         return;
  79                 }
  80
  81                 arg = (void*)name;
  82         }
  83
  84         const char *ret;
  85         if ((ret = Control_SetMode(desired_mode, arg)) != NULL) {
  86                 FCGI_RejectJSON(context, ret);
  87         } else {
  88                 FCGI_BeginJSON(context, STATUS_OK);
  89                 FCGI_JSONPair("description", "ok");
  90                 FCGI_EndJSON();
  91         }
  92 }
  93
  94 /**
  95  * Sets the mode to the desired mode, if possible.
  96  * @param desired_mode The mode to be set to
  97  * @param arg An argument specific to the mode to be set.
  98  * @return NULL on success, an error message on failure.
  99  */
 100 const char* Control_SetMode(ControlModes desired_mode, void * arg)
 101 {
 102         const char *ret = NULL;
 103
 104         pthread_mutex_lock(&(g_controls.mutex));
 105         if (g_controls.current_mode == desired_mode)
 106                 ret = "Already in the desired mode.";
 107         else if (g_controls.current_mode == CONTROL_EMERGENCY && desired_mode != CONTROL_STOP)
 108                 ret = "In emergency mode. You must stop before continuing.";
 109         else switch (desired_mode) {
 110                 case CONTROL_START:
 111                         if (g_controls.current_mode == CONTROL_STOP) {
 112                                 const char * name = arg;
 113                                 if (!*name)
 114                                         ret = "An experiment name must be specified";
 115                                 else if (strpbrk(name, INVALID_CHARACTERS))
 116                                         ret = "The experiment name must not contain: " INVALID_CHARACTERS_JSON;
 117                                 else {
 118                                         FILE *fp = fopen((const char*) arg, "a");
 119                                         if (fp) {
 120                                                 fclose(fp);
 121                                                 gettimeofday(&(g_controls.start_time), NULL);
 122                                         } else
 123                                                 ret = "Cannot open experiment name marker";
 124                                 }
 125                         } else
 126                                 ret = "Cannot start when not in a stopped state.";
 127                 break;
 128                 case CONTROL_PAUSE:
 129                         if (g_controls.current_mode != CONTROL_START)
 130                                 ret = "Cannot pause when not in a running state.";
 131                 break;
 132                 case CONTROL_RESUME:
 133                         if (g_controls.current_mode != CONTROL_PAUSE)
 134                                 ret = "Cannot resume when not in a paused state.";
 135                 break;
 136                 case CONTROL_EMERGENCY:
 137                         if (g_controls.current_mode != CONTROL_START) //pfft
 138                                 ret = "Not running so how can there be an emergency.";
 139                 break;
 140                 default:
 141                 break;
 142         }
 143
 144         if (ret == NULL) {
 145                 Actuator_SetModeAll(desired_mode, arg);
 146                 Sensor_SetModeAll(desired_mode, arg);
 147                 if (desired_mode != CONTROL_RESUME)
 148                         g_controls.current_mode = desired_mode;
 149                 else
 150                         g_controls.current_mode = CONTROL_START;
 151         }
 152         pthread_mutex_unlock(&(g_controls.mutex));
 153         return ret;
 154 }
 155
 156 /**
 157  * Gets a string representation of the current mode
 158  * @param mode The mode to get a string representation of
 159  * @return The string representation of the mode
 160  */
 161 const char * Control_GetModeName() {
 162         const char * ret = "Unknown";
 163
 164         switch (g_controls.current_mode) {
 165                 case CONTROL_START: ret = "Running"; break;
 166                 case CONTROL_PAUSE: ret = "Paused"; break;
 167                 case CONTROL_RESUME: ret = "Resumed"; break;
 168                 case CONTROL_STOP: ret = "Stopped"; break;
 169                 case CONTROL_EMERGENCY: ret = "Emergency mode"; break;
 170         }
 171         return ret;
 172 }
 173
 174 /**
 175  * Gets the start time for the current experiment
 176  * @return the start time
 177  */
 178 const struct timeval* Control_GetStartTime() {
 179         return &g_controls.start_time;
 180 }