Cloysta

A Simple Shell for Linux

This shell was intended for submittion for Florida State's Operating Systems course Fall 2015

To build: $> make

To clean: $> make clean

Known bugs:

• Limits doesn't print external commands correctly.
• Piping not functional.
• Multiple redirection doesn't work.
• Parsing a \n when you have it delimming the input results in undefined behavior

Additional comments:

Working References:

• http://stackoverflow.com/questions/1433204/how-do-i-use-extern-to-share-variables-between-source-files-in-c
• http://stackoverflow.com/questions/3356505/remove-first-char-of-string-c
• http://stackoverflow.com/questions/6967889/initializing-a-pointer-to-a-string
• http://stackoverflow.com/questions/8427436/how-can-i-check-whether-this-is-directory-path-or-any-filename-path
• http://stackoverflow.com/questions/2150291/how-do-i-measure-a-time-interval-in-c
• http://man7.org/linux/man-pages/man2/getpid.2.html
• http://stackoverflow.com/questions/16863704/stdlib-h-doesnt-have-declaration-for-putenv

Old Ideas on memory management:

void* set_memmy(int size, size_t type){

int index = set_heap();
if(index == NULL) return NULL;

ADDRS[index]->loc = calloc(size, type);
return *CHAR_ADDRS[index];

}

Instead of handling the heap internally, barring the heap from everyone, we could let each other have more direct control. However, choosing to hide the heap locations and manage internally allows for more control over garbage control. Memory leaks can at least be purged if we store an address to every allocation made. Thus, the struct of "address" allows for a total control.

/* Set Heap Based on specific size

• Allocates memory based on a specified size passed in

• / void set_array(char* name, int rows, int cols, size_t type){

  int i = 0; for(i = 0; i < MAX_HEAP_SIZE; i++){ if(ADDRS[i]->loc == NULL){ strcpy(ADDRS[i]->name, name); ADDRS[i]->type = type; ADDRS[i]->loc = malloc(rows * cols * type); return ADDRS[i]->loc; } } return NULL; }

Just the first iteration before implmenting an _next_addr()

/* Set Heap Based on specific size

• Allocates memory based on a specified size passed in

• / void set_heap(size_t size, size_t type){

  struct address * addr = _next_addr();

  if(addr == NULL) return NULL;

  strcpy(addr->name, "Default"); addr->type = type; addr->loc = malloc(size * type);

  return addr->loc; }

Just the first iteration before implmenting an _init