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OS_Project/Part3/09_memory/kernel/kernel.c
2023-11-29 17:53:40 -05:00

169 lines
6.7 KiB
C

#include "kernel.h"
// This only runs once and from there on forth only interrupts will cause something to happen
// e.g. displaying to screen and taking input from keyboard
void _start() {
// Initialize Global Variables and set up interrrupt handlers
// These variables are a vulnerability to OS security if someone can adjust
// the lower value in the kernel code (exploiting, for example, an Intel address hack)
// than kernel memory and even kernel code can be overwritten
// https://www.wired.com/story/intel-lab-istare-hack-chips/
// See libc/globals.h for KMEM_START and KMEM_END values
// See libc/globals.h for UMEM_START and UMEM_END values
kmem_addr = KMEM_START;
kernel_mem_limit = KMEM_END;
umem_addr = UMEM_START;
user_mem_limit = UMEM_END;
global_head = NULL;
global_id = 0;
isr_install();
irq_install();
kprint("Type something, it will go through the kernel\n"
"Type HELP to list commands\n> ");
}
// An interrupt calls this function to parse what was typed in, this is, essentially, your
// Command Line Interpreter for now.
void user_input(char *input) {
static u32 delete_id = 0; // static persistent variable for incrementing during test
static node* umem_head = NULL; // static persistent head variable for contiguous block allocations
if (strcmp(input, "END") == 0) {
kprint("Stopping the CPU. Bye!\n");
asm volatile("hlt");
} else if (strncmp(input, "ADD", 3) == 0) {
u32 base = 0x10000;
u32 limit = 0x100;
bool valid = true;
if (sstrlen(input, 15) > 4) {
char *args1 = input + 4;
base = digit_conver(args1);
int nDigits = digit_len(base);
if (sstrlen(args1, 15) > nDigits + 1) {
char *args2 = args1 + nDigits + 1;
limit = digit_conver(args2);
if (limit < 100) {
kprint("That memory address is to below the min of 0x100.\n");
valid = false;
}
}
if (base < 10000) {
kprint("That memory address is reserved by the Kernel, addresses must be 10000+\n");
valid = false;
}
}
if (valid) {
umem_head = add_node( umem_head, base, limit, true, global_id++);
}
} else if (strcmp(input, "LIST") == 0) {
kprint("***** FORWARD ****\n");
print_list( umem_head, true);
kprint("***** REVERSE ****\n");
print_list( umem_head, false);
} else if (strcmp(input, "SHORTLIST") == 0) {
shortprint_list( umem_head, true);
kprint("\n******************\n");
shortprint_list( umem_head, false);
} else if (strcmp(input, "PAGE") == 0) {
u32 phys_addr = 0;
u32 page = umalloc(0x4200, 0, &phys_addr);
kprint_hex( "Page: ", page, 10);
kprint_hex(", physical address: ", phys_addr, 10);
kprint("\n");
} else if (strcmp(input, "DELETE") == 0) {
umem_head = remove_node_by_id( umem_head, delete_id++);
} else if (strcmp(input, "INSERT") == 0) {
node *new_node = create_node( 0x15000, 0x1100, true, global_id++);
node *insert_point = find_id( umem_head, 3);
umem_head = insert_node( umem_head, insert_point, new_node, true);
new_node = create_node( 0x18000, 0x2100, true, global_id++);
insert_point = find_id( umem_head, 5);
umem_head = insert_node( umem_head, insert_point, new_node, false);
} else if (strcmp(input, "SORTA") == 0) {
umem_head = hacksort_list( umem_head, true);
} else if (strcmp(input, "SORTD") == 0) {
umem_head = hacksort_list( umem_head, false);
} else if (strcmp(input, "SWAP") == 0) {
node *n1 = find_id( umem_head, 1);
node *n2 = find_id( umem_head, 5);
node *n3 = find_id( umem_head, 3);
node *n4 = find_id( umem_head, 7);
swap_node_data( n1, n2);
swap_node_data( n2, n3);
swap_node_data( n3, n4);
} else if (strcmp(input, "TEST") == 0) {
char s1[10] = "ABCDFFGH\0";
char s2[10] = "ABCDEGH\0";
int x = strncmp( s1, s2, 5);
kprint_hex( "STRNCMP: ", x, 16);
kprint("\n");
x = sstrlen( s2, 10);
kprint_hex( "SSTRLEN: ", x, 10);
kprint("\n");
x = strlen( s2);
kprint_hex( "STRLEN: ", x, 10);
kprint("\n");
} else if (strcmp(input, "HELP") == 0) {
kprint("Current Commands: ADD, LIST, SHORTLIST, PAGE, DELETE,\n");
kprint(" : END, INSERT, SORTA, SORTD, SWAP, TEST, HELP\n");
kprint(" Review the kernel.c source code to see what each command does.\n");
kprint(" These are hard coded and are just examples, modify as you see fit.\n");
kprint(" for example - TEST was just added so that I could test the strlen commands.\n");
} else if (strcmp(input, "HOLES") == 0) {
print_holes(umem_head);
} else {
kprint("You said: ");
kprint(input);
kprint("\n");
}
kprint("> ");
}
int digit_len(unsigned digit) {
if (digit >= 1000000000) return 10;
if (digit >= 100000000) return 9;
if (digit >= 10000000) return 8;
if (digit >= 1000000) return 7;
if (digit >= 100000) return 6;
if (digit >= 10000) return 5;
if (digit >= 1000) return 4;
if (digit >= 100) return 3;
if (digit >= 10) return 2;
return 1;
}
int digit_conver(const char *hexString) {
u32 result = 0;
while (*hexString != '\0') {
char hexChar = *hexString;
if ((hexChar >= '0' && hexChar <= '9') || (hexChar >= 'A' && hexChar <= 'F')) {
int digit = (hexChar >= '0' && hexChar <= '9') ? (hexChar - '0') : (10 + (hexChar - 'A'));
result = result * 16 + digit;
} else {
break;
}
hexString++;
}
return result;
}
void print_holes(node* umem_head) {
if (umem_head == NULL) {
kprint("Holes list is Empty");
}
while(umem_head != NULL) {
if (umem_head->base_register - 0x10000 != 0) {
node *hole = add_node( hole, 0x10000, umem_head->base_register-0x10000, true, -1);
print_list(hole, false);
}
}
}