void *initialize_user_process(void *arg) {
PCB *start = (PCB *) malloc(sizeof(PCB));
start->registers = (int *) malloc(NumTotalRegs * sizeof(int));
int i;
for (i = 0; i < NumTotalRegs; i++) {
start->registers[i] = 0;
}
int argc = 0;
while (kos_argv[argc] != NULL) {
argc++;
}
int tempCount = argc;
int fIndex = 0;
int ptr[argc];
int topOfStack = MemorySize - 20;
while (tempCount != 0) {
tempCount--;
topOfStack -= strlen(kos_argv[fIndex]) + 1;
ptr[tempCount] = topOfStack;
strcpy(main_memory + topOfStack, kos_argv[fIndex]);
fIndex++;
}
while (topOfStack % 4) {
topOfStack--;
}
topOfStack -= 4;
int machineAddress = WordToMachine(0);
memcpy(main_memory + topOfStack, &machineAddress, 4);
fIndex = 0;
while (fIndex < argc) {
topOfStack -= 4;
machineAddress = WordToMachine(ptr[fIndex]);
memcpy(main_memory + topOfStack, &machineAddress, 4);
fIndex++;
}
int argv = topOfStack;
// envp
topOfStack -= 4;
machineAddress = WordToMachine(0);
memcpy(main_memory + topOfStack, &machineAddress, 4);
// argv
topOfStack -= 4;
machineAddress = WordToMachine(argv);
memcpy(main_memory + topOfStack, &machineAddress, 4);
// argc
topOfStack -= 4;
machineAddress = WordToMachine(argc);
memcpy(main_memory + topOfStack, &machineAddress, 4);
if (load_user_program(kos_argv[0]) < 0) {
fprintf(stderr, "Error: Unable to load user program.\n");
exit(1);
}
start->registers[StackReg] = topOfStack - 12;
start->registers[PCReg] = 0;
start->registers[NextPCReg] = 4;
Jval j = new_jval_v((void *)start);
dll_append(queue, j);
kt_exit();
}
// loads the user program, sets the stack and the registers, and then returns zero
int perform_execve(PCB *pcb, char *filename, char **kos_argv)
{
// printf("Enters perform_execve\n");
int argc = 0;
int k, tos, index, memIndex, argv;
int tempArgc; //use this to not change your original argc
while(kos_argv[argc] != NULL)
{
// printf("This is kos_argv[%i]: %s\n", argc, kos_argv[argc]);
argc++;
}
// User_Limit = pcb->user_base;
//User_Base = pcb->user_limit;
//printf("This is the argc: %i\n");
int tosPtr[argc];
//printf("This is the filename: %s\n", filename);
//printf("This is User_Base in perform_execve before load user prog: %i\n", User_Base);
// printf("This is User_Limit in perform_execve before load user prog: %i\n", User_Limit);
int loadProg = load_user_program(kos_argv[0]);
if (loadProg < 0)
{
fprintf(stderr,"Can't load program.\n");
exit(1);
}
pcb->brk = (int *)loadProg;
tos = User_Limit-24; //CHANGED THIS TO -24
/* need to back off from top of memory */
/* 12 for argc, argv, envp */
/* 12 for stack frame */
//Put "plank" on top of the stack
tempArgc= argc;
//printf("This is tempArgc: %i\n",tempArgc);
while (tempArgc!=0)
{
// printf("Goes into while loop\n");
tempArgc--;
//printf("tos: %i\n", tos);
// printf("strlen: %i\n", kos_argv[index]);
tos -= (strlen(kos_argv[index])+1);
// printf("tos : %i, tempArgc : %i\n",tos,tempArgc);
tosPtr[tempArgc] = tos;
//printf("next\n");
// printf("This is copying onto the stack[%i]: %s\n",main_memory+tos, strcpy(main_memory+tos, kos_argv[index]));
strcpy(main_memory+tos+pcb->user_base, kos_argv[index]);
index++;
}
//align the stack ptr
while (tos%4)
{
tos--;
}
//place NULL terminated ptr before anything else!
tos -= 4;
k = WordToMachine(0);
memcpy(main_memory+tos+pcb->user_base, &k, 4);
memIndex = 0;
//now placinf ptrs
while(memIndex < argc)
{
tos-= 4;
k= WordToMachine(tosPtr[memIndex]);
//printf("k: %i\n", k);
// printf("This is memcpy[%i]: %c\n", main_memory+tos, memcpy(main_memory+tos, &k, 4));
memcpy(main_memory+tos+pcb->user_base, &k, 4);
memIndex++;
// PrintStack(pcb->registers[StackReg], pcb->user_base);
}
argv = tos;
//printf("This is argv: %i\n", argv);
//Finally place in envp, argv, argc
tos -= 4;
k= WordToMachine(0);
memcpy(main_memory+tos+pcb->user_base, &k, 4);
tos -= 4;
k= WordToMachine(argv);
memcpy(main_memory+tos+pcb->user_base, &k, 4);
tos -= 4;
k= WordToMachine(argc);
memcpy(main_memory+tos+pcb->user_base, &k, 4);
pcb->registers[StackReg] = tos -12;
// printf("Ending perform_execve\n");
// PrintStack(pcb->registers[StackReg], pcb->user_base);
return 0;
}
// Loads user program, sets stack and registers
// Returns 0 on success, else errno.
int perform_execve(PCB *job, char *fn, char **argv_param) {
int machine_address;
int stack_top, index, count;
int program_value;
int argv, argc;
machine_address = 0;
stack_top = 0;
index = 0;
argv = 0;
// Get number of arguments and argv from params
argc = 0;
while( argv_param[argc] != NULL ) {
argc++;
}
int ptr[argc];
count = argc;
User_Base = job->base;
User_Limit = job->limit;
// Load program
program_value = load_user_program(argv_param[0]);
if (program_value < 0) {
fprintf(stderr, "ERROR: Can't load program into memory.\n");
do_exit((void *)job);
}
stack_top = job->limit - 24;
job->brk = (int *) program_value;
while(count != 0) {
count--;
stack_top -= (strlen(argv_param[index]) + 1);
ptr[count] = stack_top;
strcpy(main_memory + stack_top + job->base, argv_param[index]);
index++;
}
index = 0;
while(stack_top % 4) {
stack_top--;
}
stack_top -= 4;
machine_address = WordToMachine(0);
memcpy(main_memory + stack_top + job->base, &machine_address, 4);
while(index < argc) {
stack_top -= 4;
machine_address = WordToMachine(ptr[index]);
memcpy(main_memory + stack_top + job->base, &machine_address, 4);
index++;
}
// Get argv
argv = stack_top;
/* Back off from top of memory */
// 12 for argc, argv, envp
stack_top -= 4;
machine_address = WordToMachine(0); //envp
memcpy(main_memory + stack_top + job->base, &machine_address, 4);
stack_top -= 4;
machine_address = WordToMachine(argv); // argv
memcpy(main_memory + stack_top + job->base, &machine_address, 4);
stack_top -= 4;
machine_address = WordToMachine(argc); // argc
memcpy(main_memory + stack_top + job->base, &machine_address, 4);
// 12 for stack frame
job->registers[StackReg] = stack_top - 12;
return 1;
}
