executing commands in own shell - C - c

Question

I have troubles with creating my own shell in C. Here is the code I have so far
#include "interpreter.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/wait.h>
#include <syslog.h>
void readconfig(int *timeout, char *file){
FILE * fp;
char * line = NULL;
size_t len = 0;
char * token;
fp = fopen(CONFIG, "r");
if (fp == NULL)
{
*timeout = DEFAULTTIME;
}
else
{
while ((getline(&line, &len, fp)) != -1){
token = strtok(line, TOKEN);
if ((strcmp(token,TIME_PERIOD) == 0)){
*timeout = atoi(strtok(NULL, TOKEN));
}
if ((strcmp(token,HISTORY)==0)){
strcpy(file,trim_command(strtok(NULL, TOKEN)));
}
}
}
}
int waitPeriod(pid_t pid){
if(pid) {
int stat_val;
pid_t child_pid;
int time = 0;
while(time < TIME_PERIOD){
child_pid = waitpid(pid, &stat_val, WNOHANG);
if (child_pid == pid){
break;
} else if (child_pid == 0) {
time++;
sleep(1);
}
}
if (time == TIME_PERIOD){
printf("Process ended. Execution time was over. \n");
kill(pid, SIGINT);
if (kill(pid, 0) == 0){
kill(pid, SIGKILL);
}
}
if(WIFEXITED(stat_val)) {
return WEXITSTATUS(stat_val);
}
return 0;
} else {
return -1;
}
}
void splitCommand(char ** parameters, char * command, int count){
char * cm = strtok(command, " ");
int i = 0;
while (cm != NULL){
parameters[i] = malloc(strlen(cm) * sizeof(char *));
parameters[i] = cm;
i++;
cm = strtok (NULL, " ");
}
i++;
parameters[i] = NULL;
}
int getParamsCount(char command[]){
int i;
int count = 1;
int com_length = strlen(command);
for(i=0; i<com_length; i++){
if (command[i] == ' '){
count++;
}
}
return count;
}
void getHistory(FILE * history_file, char ** history_commands){
char line[MAX_INPUT];
int i = 0;
int j;
rewind(history_file);
while (fgets(line, MAX_INPUT, history_file)!= NULL){
history_commands[i] = malloc(strlen(line) * sizeof(char *));
history_commands[i] = strdup(line);
for(j=0; j<MAX_INPUT; j++){
if (history_commands[i][j] == '\n'){
history_commands[i][j] = '\0';
break;
}
}
i++;
}
}
int getNumberOfRows(FILE * history_file){
rewind(history_file);
int lines = 0;
char ch;
while(!feof(history_file)){
ch = fgetc(history_file);
if(ch == '\n'){
lines++;
}
}
return lines;
}
void printCommands(char ** history_commands, int lines){
int i = 0;
int j = 0;
for(j = i; j < lines; j++){
printf("[%d] %s\n", j, history_commands[j]);
}
}
int runCommand(pid_t pid, char * command, char ** parameters, int child){
int count = 0;
switch(pid) {
case -1 :
return -1;
case 0 :
count = getParamsCount(command);
parameters = malloc((count+1) * sizeof(char *));
splitCommand(parameters, command, count);
if (strncmp("cd", parameters[0], 2) == 0){
chdir(parameters[1]);
} else {
execvp(parameters[0], parameters[0]);
}
free(parameters);
return 0;
default :
child = waitPeriod(pid);
printf("Child status: %d\n", child);
command[0] = 0;
free(command);
return 0;
}
}
char * trim_command(char * string){
int l = strlen(string);
int i;
for (i = 0; i<l; i++){
if (string[i] == '\n'){
string[i] = '\0';
}
}
return string;
}
int main(){
char * command;
FILE * history;
char cwd[MAX_INPUT];
pid_t pid = 0;
int child = 0;
int number_of_rows = 0;
int count = 0;
char ** history_commands;
char ** parameters[10];
printf(" Safe comand line interpreter \n");
printf(" Type \"quit\" to cancel interpreter or command \n");
printf(" Type \"history\" to show full command history \n");
printf(" Type \"history number\" to execute command from history \n");
printf("________________________________________________________________________________________\n");
sleep(1);
history = fopen(HISTORY, "a+");
if (history == NULL){
printf("Could not open history file\n");
return -1;
}
while(1){
getcwd(cwd, sizeof(cwd));
printf("Command: [%d]%s : ", child, cwd);
command = malloc(MAX_INPUT * sizeof(char *));
fgets(command, MAX_INPUT, stdin);
trim_command(command);
if (strncmp(QUIT, command, 4) == 0) {
fclose(history);
return EXIT_SUCCESS;
} else if (strncmp("history", command, 7) == 0) {
number_of_rows = getNumberOfRows(history);
history_commands = malloc(number_of_rows * sizeof(char *));
getHistory(history, history_commands);
count = getParamsCount(command);
if (strcmp("history", command) == 0){
printf("HISTORY OF COMMANDS\n");
printCommands(history_commands, number_of_rows);
} else {
char * cm = strtok(command, " ");
cm = strtok(NULL, " ");
int x;
x = atoi(cm);
if (x >= number_of_rows){
printf("Command does not exist\n");
continue;
}
command = strdup(history_commands[x]);
count = getParamsCount(command);
trim_command(command);
fprintf(history, "%s\n", command);
pid = fork();
runCommand(pid, command, parameters, child);
}
} else if (command[0] != 0){
fprintf(history, "%s\n", command);
pid = fork();
runCommand(pid, command, parameters, child);
}
}
fclose(history);
return 0;
}
The problem is, it doesn't execute cd command. When I comment malloc and free lines in runCommand method, cd command starts working, but every other command without parameter is not working...
could somebody help me with this?