[NETWORK_SWITCH] Merge pull request #264 from pioneers/network_switch…

…_update

[NETWORK_SWITCH] Made much more robust for final day of final comp

.gitignore

@@ -11,6 +11,9 @@ lowcar/Device
 # ignore the entire net_handler/pbc_gen folder
 net_handler/pbc_gen
 
+# ignore network_switch/exit_status.txt
+network_switch/exit_status.txt
+
 # Log files
 *.log
 

lowcar/devices/KoalaBear/KoalaBear.cpp

@@ -31,11 +31,11 @@ uint16_t torque_read_data;
 //******************************* KOALABEAR CONSTANTS AND PARAMS ****************************//
 
 // ----------------------> CHANGE THIS TO IMPLEMENT MAX SPEED FOR KARTS <----------------------
-#define MAX_DUTY_CYCLE 0.75  // maximum duty cycle to cap how fast the motors can go: range (0, 1]
+#define MAX_DUTY_CYCLE 1.0  // maximum duty cycle to cap how fast the motors can go: range (0, 1]
 // --------------------------------------------------------------------------------------------
 
 // --------------------> CHANGE THIS TO IMPLEMENT ACCELERATION FOR KARTS <---------------------
-#define ACCEL 0.7  // acceleration of motors, in duty cycle units per second squared
+#define ACCEL 2.0  // acceleration of motors, in duty cycle units per second squared
 // --------------------------------------------------------------------------------------------
 
 // default values for PID controllers; PID control is explained in the Wiki!

network_switch/network_switch.c

@@ -1,11 +1,14 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/wait.h>
 #include "../logger/logger.h"
 #include "../runtime_util/runtime_util.h"
 #include "../shm_wrapper/shm_wrapper.h"
 
+
 #define SLEEP_DELAY 1
+#define INITIAL_SWITCH 2
 
 // Retrieves router name and password from the file name: router_txt
 void get_router_name_password(char* router_name, char* router_password, char* router_txt) {
@@ -22,16 +25,32 @@ int main() {
     shm_init();
     chdir("../network_switch");
     log_printf(INFO, "NETWORK_SWITCH initialized.");
-    bool prev_switch = false;
+    int prev_switch = 2;
+
+    char bash_exe[] = "/usr/bin/bash";
+    char script_name[] = "network_switch.sh";
 
     char local_router[32];
     char local_password[32];
+    char *local_args[5];
     char team_router[] = "teamrouter.txt";
     get_router_name_password(local_router, local_password, team_router);
+    local_args[0] = bash_exe;
+    local_args[1] = script_name;
+    local_args[2] = local_router;
+    local_args[3] = local_password;
+    local_args[4] = NULL;
+
     char pie_router[32];
     char pie_password[32];
+    char *pie_args[5];
     char pie_router_file[] = "pierouter.txt";
     get_router_name_password(pie_router, pie_password, pie_router_file);
+    pie_args[0] = bash_exe;
+    pie_args[1] = script_name;
+    pie_args[2] = pie_router;
+    pie_args[3] = pie_password;
+    pie_args[4] = NULL;
 
     while (1) {
         dev_id_t dev_ids[MAX_DEVICES];
@@ -58,19 +77,49 @@ int main() {
                 device_t* device = get_device(dev_ids[idx].type);
                 param_val_t param_data[MAX_PARAMS];
                 device_read(idx, NET_HANDLER, DATA, get_readable_param_bitmap(device->type), param_data);
-                bool curr_switch = param_data[device->num_params - 1].p_b;  // network switch value is the last parameter
-                if (curr_switch != prev_switch) {
-                    if (!curr_switch) {  // switch to pioneers if curr_switch is false
-                        snprintf(total_command, sizeof(total_command), "./network_switch.sh %s %s", pie_router, pie_password);
-                        system(total_command);
+                bool curr_switch_bool = param_data[device->num_params - 1].p_b;  // network switch value is the last parameter
+                int curr_switch;
+                if (curr_switch_bool) {
+                    curr_switch = 1;
+                } else if (!curr_switch_bool) {
+                    curr_switch = 0;
+                }
+                while (curr_switch != prev_switch) {
+                    int status;
+                    if (curr_switch == 0) {  // switch to pioneers if curr_switch is false
+                        pid_t pid;
+                        if ((pid = fork()) < 0) {
+                            log_printf(ERROR, "network_switch: Failed to fork");
+                            sleep(SLEEP_DELAY);
+                        } else if (pid == 0) {
+                            execv(bash_exe, pie_args); // call the bash script with pioneers router arguments
+                        } else {
+                            waitpid(pid, &status, 0);
+                        }
                     } else {  // switch to student's router if curr_switch is true
-                        snprintf(total_command, sizeof(total_command), "./network_switch.sh %s %s", local_router, local_password);
-                        system(total_command);
+                        pid_t pid;
+                        if ((pid = fork()) < 0) {
+                            log_printf(ERROR, "network_switch: Failed to fork");
+                            sleep(SLEEP_DELAY);
+                        } else if (pid == 0) {
+                            execv(bash_exe, local_args); // call the bash script with local router arguments
+                        } else {
+                            waitpid(pid, &status, 0);
+                        }
+                    }
+                    char buf[5]; 
+                    FILE* exit_status = fopen("exit_status.txt", "r");
+                    fgets(buf, 5, exit_status); // retrieve the output of the bash script in the exit_status.txt
+                    if (strcmp(buf, "1") == 0) { // if output is 1, we successfully connected. Set previous switch = current switch
+                        log_printf(WARN, "SUCCESSFULLY CONNECTED TO NETWORK");
+                        prev_switch = curr_switch;
+                    } else { // if output is not 1, we loop again to call the bash script again
+                        log_printf(WARN, "FAILED TO CONNECT TO NETWORK");
                     }
-                    prev_switch = curr_switch;
+                    fclose(exit_status);
                 }
             }
         }
         sleep(SLEEP_DELAY);
     }
-}
+}

network_switch/network_switch.sh

@@ -1,8 +1,58 @@
 #!/bin/bash
 
-# move into folder with all the network names the potato connected to previously 
-cd /etc/NetworkManager/system-connections
-sudo rm * # remove all network names
-sudo nmcli d wifi connect $1 password $2 # connect to wifi determined by network switch 
+# script takes two arguments, the first being the name of the network to connect to,
+# the second being the password to that network
 
-# keep trying to connect until wifi is connected, check by looping through output of nmcli d 
+# script returns 1 if successfully connected, 0 if unsuccessful
+
+# forget all networks by removing all network configuration files in nmcli folders
+sudo rm /etc/NetworkManager/system-connections/*
+
+# initiate rescan of networks; this command only starts the scan, it doesn't wait for scan to complete
+sudo nmcli dev wifi rescan
+
+# wait 3 seconds, look for the network name in the output of nmcli d wifi list
+# repeat a maximum of 3 times (arbitrarily chosen nmumbers)
+pass=0
+for i in {1..3}; do
+    # if passed, break early
+    if [[ $pass == 1 ]]; then
+        break;
+    fi
+
+    sleep 3
+    printf "Try number $i ...\n"
+
+    while read line; do
+        if [[ $line == *"$1"* ]]; then
+            pass=1
+            break
+        fi
+    done <<< "$(nmcli d wifi list)"
+done
+
+printf "Going to connect!\n"
+
+# connect to the network; again do not proceed before action is complete
+sudo nmcli d wifi connect $1 password $2
+
+# we use the command nmcli -t -f CONNECTION,STATE device to get the state of NetworkManager
+# we look for a line that is exactly <network_name>:connected
+# for example, if successfully connect to pioneers, the output will contain:
+# pioneers:connected
+pass=0
+while read line; do
+    if [[ $line == "$1:connected" ]]; then
+        pass=1
+        break
+    fi
+done <<< "$(nmcli -t -f CONNECTION,STATE device)"
+
+# write "1" or "0" to exit_status.txt to give the C program the result of this script
+if [[ $pass == 1 ]]; then
+    printf "1" > exit_status.txt
+else
+    printf "0" > exit_status.txt
+fi
+
+exit $pass