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 bool PathExists(const char *path)
  19 {
  20         FILE *fp = fopen(path, "r");
  21         if (fp) {
  22                 fclose(fp);
  23                 return true;
  24         }
  25         return false;
  26 }
  27
  28 /**
  29  * System control handler. This covers high-level control, including
  30  * admin related functions and starting/stopping experiments..
  31  * @param context The context to work in
  32  * @param params The input parameters
  33  */
  34 void Control_Handler(FCGIContext *context, char *params) {
  35         const char *action, *key = "", *name = "";
  36         bool force = false;
  37         ControlModes desired_mode;
  38
  39         FCGIValue values[4] = {
  40                 {"action", &action, FCGI_REQUIRED(FCGI_STRING_T)},
  41                 {"key", &key, FCGI_STRING_T},
  42                 {"force", &force, FCGI_BOOL_T},
  43                 {"name", &name, FCGI_STRING_T}
  44         };
  45
  46         if (!FCGI_ParseRequest(context, params, values, 4))
  47                 return;
  48
  49         if (!strcmp(action, "lock")) {
  50                 FCGI_LockControl(context, force);
  51                 return;
  52         } else if (!strcmp(action, "emergency")) {
  53                 desired_mode = CONTROL_EMERGENCY;
  54         } else if (FCGI_HasControl(context, key)) {
  55                 if (!strcmp(action, "release")) {
  56                         FCGI_ReleaseControl(context);
  57                 } else if (!strcmp(action, "start")) {
  58                         desired_mode = CONTROL_START;
  59                 } else if (!strcmp(action, "pause")) {
  60                         desired_mode = CONTROL_PAUSE;
  61                 } else if (!strcmp(action, "resume")) {
  62                         desired_mode = CONTROL_RESUME;
  63                 } else if (!strcmp(action, "stop")) {
  64                         desired_mode = CONTROL_STOP;
  65                 } else {
  66                         FCGI_RejectJSON(context, "Unknown action specified.");
  67                         return;
  68                 }
  69         } else {
  70                 FCGI_RejectJSONEx(context, STATUS_UNAUTHORIZED,
  71                         "Invalid control key specified.");
  72                 return;
  73         }
  74
  75         void *arg = NULL;
  76         if (desired_mode == CONTROL_START) {
  77                 if (PathExists(name) && !force) {
  78                         FCGI_RejectJSON(context, "An experiment with that name already exists.");
  79                         return;
  80                 }
  81
  82                 arg = (void*)name;
  83         }
  84
  85         const char *ret;
  86         if ((ret = Control_SetMode(desired_mode, arg)) != NULL) {
  87                 FCGI_RejectJSON(context, ret);
  88         } else {
  89                 FCGI_BeginJSON(context, STATUS_OK);
  90                 FCGI_JSONPair("description", "ok");
  91                 FCGI_EndJSON();
  92         }
  93 }
  94
  95 /**
  96  * Sets the mode to the desired mode, if possible.
  97  * @param desired_mode The mode to be set to
  98  * @param arg An argument specific to the mode to be set.
  99  * @return NULL on success, an error message on failure.
 100  */
 101 const char* Control_SetMode(ControlModes desired_mode, void * arg)
 102 {
 103         const char *ret = NULL;
 104
 105         pthread_mutex_lock(&(g_controls.mutex));
 106         if (g_controls.current_mode == desired_mode)
 107                 ret = "Already in the desired mode.";
 108         else if (g_controls.current_mode == CONTROL_EMERGENCY && desired_mode != CONTROL_STOP)
 109                 ret = "In emergency mode. You must stop before continuing.";
 110         else switch (desired_mode) {
 111                 case CONTROL_START:
 112                         if (g_controls.current_mode == CONTROL_STOP) {
 113                                 const char * name = arg;
 114                                 if (!*name)
 115                                         ret = "An experiment name must be specified";
 116                                 else if (strpbrk(name, INVALID_CHARACTERS))
 117                                         ret = "The experiment name must not contain: " INVALID_CHARACTERS_JSON;
 118                                 else {
 119                                         FILE *fp = fopen((const char*) arg, "a");
 120                                         if (fp) {
 121                                                 fclose(fp);
 122                                                 gettimeofday(&(g_controls.start_time), NULL);
 123                                         } else
 124                                                 ret = "Cannot open experiment name marker";
 125                                 }
 126                         } else
 127                                 ret = "Cannot start when not in a stopped state.";
 128                 break;
 129                 case CONTROL_PAUSE:
 130                         if (g_controls.current_mode != CONTROL_START)
 131                                 ret = "Cannot pause when not in a running state.";
 132                 break;
 133                 case CONTROL_RESUME:
 134                         if (g_controls.current_mode != CONTROL_PAUSE)
 135                                 ret = "Cannot resume when not in a paused state.";
 136                 break;
 137                 case CONTROL_EMERGENCY:
 138                         if (g_controls.current_mode != CONTROL_START) //pfft
 139                                 ret = "Not running so how can there be an emergency.";
 140                 break;
 141                 default:
 142                 break;
 143         }
 144
 145         if (ret == NULL) {
 146                 Actuator_SetModeAll(desired_mode, arg);
 147                 Sensor_SetModeAll(desired_mode, arg);
 148                 if (desired_mode != CONTROL_RESUME)
 149                         g_controls.current_mode = desired_mode;
 150                 else
 151                         g_controls.current_mode = CONTROL_START;
 152         }
 153         pthread_mutex_unlock(&(g_controls.mutex));
 154         return ret;
 155 }
 156
 157 /**
 158  * Gets a string representation of the current mode
 159  * @param mode The mode to get a string representation of
 160  * @return The string representation of the mode
 161  */
 162 const char * Control_GetModeName() {
 163         const char * ret = "Unknown";
 164
 165         switch (g_controls.current_mode) {
 166                 case CONTROL_START: ret = "Running"; break;
 167                 case CONTROL_PAUSE: ret = "Paused"; break;
 168                 case CONTROL_RESUME: ret = "Resumed"; break;
 169                 case CONTROL_STOP: ret = "Stopped"; break;
 170                 case CONTROL_EMERGENCY: ret = "Emergency mode"; break;
 171         }
 172         return ret;
 173 }
 174
 175 /**
 176  * Gets the start time for the current experiment
 177  * @return the start time
 178  */
 179 const struct timeval* Control_GetStartTime() {
 180         return &g_controls.start_time;
 181 }