I was trying to create a program where I could parse the command and parameters enters by the user into specific arrays (these commands and params would execute commands like "ls", "ls -l", "ls -l | wc" However, I am having problem with parsing:
//Split the command and store each string in parameter[]
cp = (strtok(command, hash)); //Get the initial string (the command)
parameter[0] = (char*) malloc(strlen(cp)+ 1); //Allocate some space to the first element in the array
strncpy(parameter[0], cp, strlen(cp)+ 1);
for(i = 1; i < MAX_ARG; i++)
{
cp = strtok(NULL, hash); //Check for each string in the array
parameter[i] = (char*) malloc(strlen(cp)+ 1);
strncpy(parameter[i], cp, strlen(cp)+ 1); //Store the result string in an indexed off array
if(parameter[i] == NULL)
{
break;
}
if(strcmp(parameter[i], "|") == 0)
{
cp = strtok(NULL, hash);
parameter2[0] = (char*) malloc(strlen(cp)+ 1);
strncpy(parameter2[0], cp, strlen(cp)+ 1);
//Find the second set of commands and parameters
for (j = 1; j < MAX_ARG; j++)
{
cp = strtok(NULL, hash);
if (cp == NULL)
{
leave = 1;
break;
}
else
{
parameter2[j] = (char*) malloc(strlen(cp)+ 1);
strncpy(parameter2[j], cp, strlen(cp)+ 1);
}
}
}
if (leave == 1)
{
break;
}
}
I run into a problem when I do if (strlen(cp) == NULL), there is a segmentation fault. I am trying to break out of the larger for loop once all the inputs have been entered into arrays. I can succesfully enter the correct string elements into the arrays but I just can't exit the loop once I have done so.
strtok
may return NULL pointers if can't found more tokens. So, you must check cp
value before using it:
cp = strtok(NULL, hash);
if (cp != NULL)
{
........
}
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