diff --git a/student-distrib/proc.c b/student-distrib/proc.c
index 25eb4ac954272c56f14cff1cfe664048de213ca4..2621e745839f062f1833e5ac3c7741e88fe65fb8 100644
--- a/student-distrib/proc.c
+++ b/student-distrib/proc.c
@@ -35,7 +35,8 @@ int32_t fd_check(int32_t fd)
if (fd >= MIN_FILE_NUM && fd < MAX_FILE_NUM )
{
/* Now check if file is present */
- if ( terminal[ running_terminal].pcb->fd[fd].flags != 0)
+ // // use running_terminal instead of visible_terminal !!!
+ if ( terminal[running_terminal].pcb->fd[fd].flags != 0)
return 0;
}
return -1;
@@ -44,13 +45,14 @@ int32_t fd_check(int32_t fd)
//clearing fd
void fd_clear(int32_t fd)
{
- terminal[ running_terminal].pcb->fd[fd].fileop_ptr.read = 0;
- terminal[ running_terminal].pcb->fd[fd].fileop_ptr.write = 0;
- terminal[ running_terminal].pcb->fd[fd].fileop_ptr.open = 0;
- terminal[ running_terminal].pcb->fd[fd].fileop_ptr.close = 0;
- terminal[ running_terminal].pcb->fd[fd].inode_index = 0;
- terminal[ running_terminal].pcb->fd[fd].file_pos = 0;
- terminal[ running_terminal].pcb->fd[fd].flags = 0;
+ // use running_terminal instead of visible_terminal !!!
+ terminal[running_terminal].pcb->fd[fd].fileop_ptr.read = 0;
+ terminal[running_terminal].pcb->fd[fd].fileop_ptr.write = 0;
+ terminal[running_terminal].pcb->fd[fd].fileop_ptr.open = 0;
+ terminal[running_terminal].pcb->fd[fd].fileop_ptr.close = 0;
+ terminal[running_terminal].pcb->fd[fd].inode_index = 0;
+ terminal[running_terminal].pcb->fd[fd].file_pos = 0;
+ terminal[running_terminal].pcb->fd[fd].flags = 0;
return;
}
diff --git a/student-distrib/syscall.c b/student-distrib/syscall.c
index f581486da377dd23026afb588c3ac038b2dfe8ab..f8963f29a622a54b7058983b192e5eb14330458f 100644
--- a/student-distrib/syscall.c
+++ b/student-distrib/syscall.c
@@ -6,20 +6,16 @@
*
* DESCRIPTION: This function terminates a process, returning the specified value to its parent process.
*
- * INPUT: status --
+ * INPUT: status
*
- * RETURN:
+ * RETURN: always return 0
*/
-int32_t halt (uint8_t status)
-{
+int32_t halt (uint8_t status) {
int i;
cli();
pcb_t* pcb_cur = terminal[running_terminal].pcb;
-
- // printf("[halt] running_terminal = %d\n", running_terminal);
-
pcb_t* pcb_prev = pcb_cur->parent_pcb;
/* set all present flags in PCB to "Not In Use" */
@@ -38,6 +34,7 @@ int32_t halt (uint8_t status)
terminal[pcb_cur->running_terminal].terminal_prog_count--;
}
+ // exiting "root shell"
if(terminal[running_terminal].terminal_prog_count == 0)
{
printf("[halt] executing new shell...\n");
@@ -57,13 +54,12 @@ int32_t halt (uint8_t status)
clear_pid(pcb_cur->pid);
-
//------------------ Jump to execute return --------------------------------
asm volatile(
"movl %0, %%eax;"
- "movl %1, %%esp;"
- "movl %2, %%ebp;"
+ "movl %1, %%esp;" // restore parent_esp
+ "movl %2, %%ebp;" // restore parent_ebp
"jmp exec_ret"
:
:"r"((uint32_t)status), "r"(pcb_cur->parent_esp), "r"(pcb_cur->parent_ebp)
@@ -94,18 +90,12 @@ int32_t execute(const uint8_t* command)
cli();
- // if command == NULL, abort
+ // invalid command
if(command == NULL) return -1;
- // if(strncmp("\n", command, 1) == 0)
- // return 0;
-
if(strlen((int8_t *) command) == 1)
return 0;
- // printf("[EXE] running_terminal = %d\n", running_terminal);
- // printf("[EXE] (command) = %s\n", command);
-
//------------------ 0 : Parse args ----------------------------------------
uint8_t parsed_cmd[MAX_COMMAND_SIZE];
@@ -116,24 +106,15 @@ int32_t execute(const uint8_t* command)
ret = parse_cmd(command, parsed_cmd, argv);
- /* For keyboard interrupts */
- //sti();
-
- //set argument number for pcb initialization
-
+ // set argument number for pcb initialization
arg_num = (ret > -1) ? ret : 0;
- if(ret == -1)
-
- return -1;
-
- else if(ret == -2)
+ if(ret == -1) return -1;
- exit();
+ if(ret == -2) exit();
//------------------ 1: Executable check -----------------------------------
- // if cpu reaches its maximum control, abort
if(total_prog_count >= MAX_PROCESS)
{
printf("[execute] Reached maximum number of processes %d\n", MAX_PROCESS);
@@ -153,20 +134,19 @@ int32_t execute(const uint8_t* command)
{
return -1;
}
+ // if not an executable file
if ( (buf[0] != AS_DEL) || (buf[1] != AS_E) || (buf[2] != AS_L) || (buf[3] != AS_F) )
{
return -1;
}
- // Get free PID index
+ // Get a new pid
pid = set_pid();
- /* Test variables */
total_prog_count++;
terminal[running_terminal].terminal_prog_count++;
//get entry point from bytes 24 to 27 in exe file
read_data( dentry.inode_index, ENTRY_POINT, buf, 4);
-
entry_point = *((uint32_t*)buf);
//-------------------- 3: Paging -------------------------------------------
@@ -215,16 +195,7 @@ int32_t execute(const uint8_t* command)
if(strncmp("shell", (int8_t *) parsed_cmd, 5) == 0)
terminal[running_terminal].pcb->shell_flag = 1;
- //printf("[EXE] using pcb = %x\n", terminal[running_terminal].pcb);
-
- //printf("[EXE] set pcb ebp to %x , esp to %x\n", terminal[running_terminal].pcb->current_ebp, terminal[running_terminal].pcb->current_esp);
- //printf("[EXE] should be ebp %x , esp %x\n", temp_ebp, temp_esp);
- //--------------------- 6: scheduling initilization -----------------------
-
-
-
-
- //--------------------- 7: context switch-----------------------------------
+ //--------------------- 6: context switch-----------------------------------
// update SS0 and ESP0 in Task State Segment when switching context
tss.ss0 = KERNEL_DS;
@@ -308,8 +279,6 @@ int32_t write (int32_t fd, const void* buf, int32_t nbytes){
int32_t ret;
- //printf("[sys write] before = %d\n", running_terminal);
-
if (fd_check(fd) < 0 || fd == STDIN_FD) return -1; // invalid fd
if (buf == NULL) return -1; // invalid buf
@@ -318,8 +287,6 @@ int32_t write (int32_t fd, const void* buf, int32_t nbytes){
ret = terminal[running_terminal].pcb->fd[fd].fileop_ptr.write(fd, buf, nbytes);
- //printf("[sys write] after = %d\n", running_terminal);
-
return ret;
}
@@ -339,41 +306,38 @@ int32_t open (const uint8_t* filename){
int i;
int fd = -1;
- int type;
dentry_t dentry;
- //terminal[ running_terminal].pcb = current_pcb();
-
- /* Valid file name check */
+ // invalid file name
if( strlen( (char*)filename ) == 0 ) return -1;
-
+
/* File does not exist */
if( read_dentry_by_name(filename, &(dentry)) != 0 ) return -1;
/* File type checks */
- type = dentry.file_type;
- if( type < 0 || type > 2) return -1;
+ if( dentry.file_type < 0 || dentry.file_type > 2) return -1;
/* Looking for available space in FD table */
for(i = USER_FILE_START; i < MAX_FILE_NUM; i++){
- /* Check if FD table entry is unused */
+ // if we can find a free fd
if( terminal[ running_terminal].pcb->fd[i].flags == 0)
{
fd = i;
break;
}
- /* FD table is full */
+ // no free fd
if(i == MAX_FILE_NUM-1) return -1;
-
}
- terminal[ running_terminal].pcb->fd[fd].inode_index = (type == 2)? dentry.inode_index : 0;
- terminal[ running_terminal].pcb->fd[fd].file_pos = 0;
- terminal[ running_terminal].pcb->fd[fd].flags = 1;
+ // only regular file has inode, for other file types, set inode to 0
+ terminal[running_terminal].pcb->fd[fd].inode_index = (dentry.file_type == 2)? dentry.inode_index : 0;
+ terminal[running_terminal].pcb->fd[fd].file_pos = 0;
+ terminal[running_terminal].pcb->fd[fd].flags = 1;
- switch (type) {
+ // insert file specific operation table
+ switch (dentry.file_type) {
case 0:
terminal[ running_terminal].pcb->fd[fd].fileop_ptr = rtc_jumptable;
break;
@@ -385,9 +349,7 @@ int32_t open (const uint8_t* filename){
break;
}
- //sti();
-
- terminal[running_terminal].pcb->fd[fd].fileop_ptr.open(filename);
+ terminal[running_terminal].pcb->fd[fd].fileop_ptr.open(filename);
return fd;
}
@@ -408,8 +370,10 @@ int32_t open (const uint8_t* filename){
*/
int32_t close (int32_t fd)
{
+
+ // invalid fd
if(fd_check(fd) < 0 || fd < USER_FILE_START)
- return -1; // invalid fd
+ return -1;
terminal[running_terminal].pcb->fd[fd].fileop_ptr.close(fd);
@@ -437,25 +401,19 @@ int32_t getargs (uint8_t* buf, int32_t nbytes){
uint8_t* argument;
- //terminal[ running_terminal].pcb = current_pcb();
argument = (uint8_t*) (terminal[running_terminal].pcb->argv);
- if( terminal[running_terminal].pcb->arg_num == 0 || nbytes <= 0 )
+ //If there are no arguments
+ if ( terminal[running_terminal].pcb->arg_num == 0 || nbytes <= 0 )
{
- //printf("[getargs] return -1\n");
- return -1; //If there are no arguments
+ return -1;
}
- //if the arguments and a terminal NULL (0-byte) do not fit in the buffer.
+ // if the arguments and a terminal NULL (0-byte) do not fit in the buffer.
nbytes = (nbytes > MAX_ARGUMENT_SIZE * MAX_ARGUMENT_NUM) ? MAX_ARGUMENT_SIZE * MAX_ARGUMENT_NUM : nbytes;
memcpy(buf, argument, nbytes);
- // uint32_t i;
- // //printf("[getargs] argument number = %d\n", terminal[ running_terminal].pcb->arg_num);
- // for(i = 0; i < terminal[ running_terminal].pcb->arg_num; i++)
- // //printf("[getargs] buf[%d] = %s\n", i, buf+i*MAX_ARGUMENT_SIZE);
- //printf("[getargs] return 0\n");
return 0;
}
@@ -467,7 +425,7 @@ int32_t getargs (uint8_t* buf, int32_t nbytes){
* Although the address returned is always the same, it should be written into the memory
* location provided by the caller (which must be checked for validity).
*
- * INPUT: screen_start --
+ * INPUT: screen_start
*
* RETURN: -1 If the location is invalid.
*
@@ -492,7 +450,7 @@ int32_t vidmap (uint8_t** screen_start)
remap_vidmem();
- *screen_start = (uint8_t *)(0x8400000);
+ *screen_start = (uint8_t *)(0x8400000); // 132MB, video memory starting address
return 0x8400000;
}