Shell documentation

Limits of the shell:

Name	Limit
Command length	256 characters
Arguments	128 characters
Directory path	256 characters

However, these shell limits are subject to change ( ͡° ͜ʖ ͡°)

How the shell works

shell.c

Includes

Headers included in shell.c

• ../drivers/debug.h
• ../drivers/filesystem/fat.h
• ../drivers/pit.h
• ../drivers/ps2_keyboard.h
• ../drivers/sound.h
• ../drivers/storage/device.h
• ../drivers/utils.h
• ../drivers/vga.h
• ../drivers/vbe.h
• ../gui/desktop.h
• ../kernel/panic.h
• ../memory/kmalloc.h
• ../memory/pmm.h
• shell.h
• terminal.h
• <stdint.h>

Definitions

Definitions declared in shell.c

#define MAX_COMMAND_LENGTH 256
#define MAX_ARGUMENTS 128

Variables

Variables declared in shell.c

FAT_filesystem_t* s_fat_fs = NULL;
char currentDir[256] = "root";

Type declarations

Types declated in shell.c

typedef int (*math_op_t)(int, int);

Functions

Functions declared in shell.c

List:

• add
• subtract
• divide
• multiply
• find_last_slash
• starts_with
• cpuid
• get_cpu_info
• handle_return_code
• handle_command
• parse_command
• shell_start

Definitions:

int add(int a, int b);
int subtract(int a, int b);
int divide(int a, int b);
int multiply(int a, int b);

char* find_last_slash(char* str);
int starts_with(const char *str, const char *prefix);
void cpuid(uint32_t eax_in, uint32_t* eax, uint32_t* ebx, uint32_t* ecx, uint32_t* edx);
void get_cpu_info(char* vendor, char* brand);
static handle_return_code(int return_code, int argc, char** argv);
static void handle_command(int argc, const char** argv);
static void parse_command(char* command, unsigned length);

void shell_start();

shell.h

Includes

Headers included in shell.h

• ../drivers/filesystem/fat.h

Variables

Variables declared in shell.h

List:

extern FAT_filesystem_t* s_fat_fs;
extern char currentDir[256];