/*shell.c

Michael Black, 2007

Creates the shell and handles the shell commands.

The shell is automatically loaded by the kernel

*/

#include "lib.h"

void doshell();

/*the shell starts here*/

main()

{

/*enable interrupts*/

setup();

/*start the main shell routine*/

doshell();

/*terminate - this shouldn't run*/

exit();

}

/*compares command with line. if they are equal, returns 1, else 0*/

int iscommand(char* line, char* command)

{

int i=0;

/*step through until reach end of string*/

while(command[i]!='\0')

{

if (line[i]!=command[i])

return 0;

i++;

}

return 1;

}

char* getDirArgument(char *line)

{

int i = 0;

int j = 0;

while(line[i]!=' ')

i++;

i++;

}

/*returns the first argument after the command*/

char* getargument(char* line)

{

int i=0;

int j=0;

/*find the space*/

while(line[i]!=' ')

i++;

i++;

/*find the end and replace it with a \0*/

j=i;

while(line[j]!=0xd)

{

j++;

if (j-i==6)

break;

}

line[j]=0x0;

return line+i;

}

/*execute a program. fore is 1 if the shell is meant to be paused while the program runs*/

void doexecute(char* line, int fore)

{

char program[12800];

/*extract the name from the command line*/

char* name=getargument(line);

/*check that a program is loaded by putting 0 in the first byte. if it stays, wasn't loaded*/

/*I guess it's bad luck if the program starts with 0*/

program[0]=0x0;

readfile(name,program);

if (program[0]==0x0)

{

printstring("Program not found\r\n\0");

}

else

{

/*use fore to pick one of the library functions*/

if (fore==1)

executeprogram(program,12800);

else

executeprogrambackground(program,12800);

}

}

/*load the file and print out the contents. assume that's it's ASCII*/

void dotype(char* line)

{

char file[12800];

char* name=getargument(line);

file[0]=0x1;

readfile(name,file);

if (file[0]==0x1)

{

printstring("File not found\r\n\0");

}

else

{

printstring(file);

}

}

/*print out a help screen*/

void dohelp()

{

printstring("The commands are: \r\n\0");

printstring(" CLS: Clear the screen\r\n\0");

printstring(" COPY: Copy one file to another with a different name\r\n\0");

printstring(" CREATE <FILE_NAME>: Create a text file FILE_NAME\r\n\0");

printstring(" DELETE <FILE_NAME>: Delete the file FILE_NAME\r\n\0");

printstring(" DIR: Print out the directory\r\n\0");

printstring(" EXEC <PROGRAM_NAME>: Run the program PROGRAM_NAME\r\n\0");

printstring(" EXECBACK <PROGRAM_NAME>: Run PROGRAM_NAME as a background process\r\n\0");

printstring(" HELP or ?: Print this message\r\n\0");

printstring(" KILL <PROCESS_NUMBER>: Terminate the process with the id PROCESS_NUMBER\r\n\0");

printstring(" TYPE <FILE_NAME>: Print out the contents of file FILE_NAME\r\n\0");

printstring(" MKDIR <DIR_NAME>: Create Directory\r\n\0");

printstring(" LS <DIR_NAME>: List Directory\r\n\0");

}

/*

void domkdir(char* dirName)

{

char* name=getargument(dirName);

mkdir(name);

}*/

char *getFirstParameter(char *line)

{

char *name;

char *path;

char *command;

int i=0;

int j=0;

while(line[i] != ' ')

{

i++;

}

i++;

j=0;

while(line[i] != ' ' )

{

path[j] = line[i];

i++;

j++;

}

//j++;

path[j] = '\0';

//printstring("first: ");

//printstring(path);

return path;

}

char *getSecondParameter(char *line)

{

char *name;

char *path;

char *command;

int i=0;

int j=0;

while(line[i] != ' ')

{

command[j] = line[i];

i++;

j++;

}

i++;

j++;

command[j] = '\0';

j=0;

while(line[i] != ' ')

{

path[j] = line[i];

i++;

j++;

}

i++;

j++;

path[j] = '\0';

j=0;

while(line[i] != ' ')

{

name[j] = line[i];

i++;

j++;

}

i++;

j++;

name[j] = '\0';

return name;

}

void domkdir(char* line)

{

char *name;

char *path;

path = getFirstParameter(line);

name = getSecondParameter(line);

mkdir(path,name);

//mkdirFS(name);

}

void dols(char * path)

{

char * pathToList;

pathToList = getargument(path);

ls(pathToList);

}

/*allow the user to create a text file*/

void docreate(char* line)

{

char file[12800];

int index=0;

char* name=getargument(line);

char c=0;

printstring("Enter your text. End the file by typing CTRL-C.\r\n\n\0");

/*terminates when user presses CTRL-C - 3) */

while(c!=0x3)

{

/*get a character and store it*/

c=getchar();

file[index++]=c;

/*echo it back if it isn't CTRL-C*/

if (c!=0x3)

putchar(c);

/*if the user presses ENTER, follow the CR with a LF*/

if (c==0xd)

{

file[index++]=0xa;

putchar(0xa);

}

}

/*terminate the file with a 0*/

file[index-1]=0x0;

/*write it to the disk. Round up the sector*/

writefile(name,file,mydiv(index,512)+1);

printstring("\r\n\0");

}

/*delete a file*/

void dodelete(char* line)

{

char* name=getargument(line);

/*make the system call*/

deletefile(name);

}

/*print out the directory*/

void dodir()

{

char dirsector[512];

char mapsector[512];

char name[7];

int i,j,index,files;

/*read the directory sector*/

readsector(2,dirsector);

printstring("Directory:\r\n\0");

index=0;

files=0;

/*the file system allows no more than 16 files*/

for (i=0; i<16; i++)

{

/*check if the file exists*/

if (dirsector[index]!=0)

{

/*print hte name*/

for (j=0; j<6; j++)

name[j]=dirsector[index+j];

name[6]=0;

printstring(name);

/*calculate the file size in sectors from the directory entry*/

j=0;

while(dirsector[index+j+6]!=0)

j++;

printstring(" \0");

printnumber(j);

printstring(" sectors\r\n\0");

files++;

}

/*move to the next entry*/

index=index+0x20;

}

printnumber(files);

printstring(" files total (out of 16 maximum)\r\n\0");

/*read the map sector to find out how many free sectors are left*/

readsector(1,mapsector);

j=0;

for (i=0; i<256; i++)

{

if (mapsector[i]==0x0)

j++;

}

printnumber(j);

printstring(" sectors available\r\n\0");

}

/*finds where a file name exists within the directory*/

int findname(char* name, char* sector)

{

int i,j,index=0;

/*search the directory until we find name*/

/*after 16 entries, quit*/

for (i=0; i<16; i++)

{

/*not a file? continue*/

if (sector[index]==0)

{

index=index+0x20;

continue;

}

/*try to match name*/

for (j=0; j<6; j++)

{

if (name[j]=='\0' && sector[index+j]==0x20)

{

j=6;

break;

}

if (name[j]!=sector[index+j])

break;

}

/*name matches, break*/

if (j==6)

break;

index=index+0x20;

}

/*did we not find it? then return -1*/

if (i==16)

{

return -1;

}

return index;

}

/*copy a file*/

void docopy()

{

char sname[7];

char dname[7];

char line[80];

char file[12800];

char dirsector[512];

int index,i;

/*prompt for the first file name*/

printstring("Name of the source file? \0");

readstring(line);

for (i=0; i<6; i++)

{

sname[i]=line[i];

if (line[i]==0xd)

break;

}

sname[i]=0x0;

/*make sure it exists - find the directory entry*/

readsector(2,dirsector);

index=findname(sname,dirsector);

if (index==-1)

{

printstring("File not found\r\n\0");

return;

}

/*read the source file*/

readfile(sname,file);

/*prompt for the destination file name*/

printstring("Name of the destination file? \0");

readstring(line);

for (i=0; i<6; i++)

{

dname[i]=line[i];

if (line[i]==0xd)

break;

}

dname[i]=0x0;

/*figure out how long the source file is*/

i=0;

index=index+6;

while(dirsector[index]!=0x0)

{

index++;

i++;

}

/*write the file*/

writefile(dname,file,i);

}

/*kill a process*/

void dokill(char* line)

{

/*make the system call*/

char* arg=getargument(line);

int21(9,arg[0]-0x30);

}

/*clear the screen*/

void doclear()

{

clearscreen();

setcursor(0,0);

}

void dops()

{

ps();

}

/*this is the main routine*/

void doshell()

{

char line[80];

/*run forever - the shell shouldn't end*/

while(1==1)

{

/*read in a line*/

printstring("SHELL>\0");

readstring(line);

/*match it against each possible command*/

/*if the user presses return, ignore it*/

if (line[0]==0xd)

continue;

else if (iscommand(line,"CLS\0")==1)

doclear();

else if (iscommand(line,"cls\0")==1)

doclear();

else if (iscommand(line,"COPY\0")==1)

docopy();

else if (iscommand(line,"copy\0")==1)

docopy();

else if (iscommand(line,"CREATE \0")==1)

docreate(line);

else if (iscommand(line,"create \0")==1)

docreate(line);

else if (iscommand(line,"DELETE \0")==1)

dodelete(line);

else if (iscommand(line,"delete \0")==1)

dodelete(line);

else if (iscommand(line,"DIR\0")==1)

dodir();

else if (iscommand(line,"dir\0")==1)

dodir();

else if (iscommand(line,"EXEC \0")==1)

doexecute(line,1);

else if (iscommand(line,"exec \0")==1)

doexecute(line,1);

else if (iscommand(line,"EXECBACK \0")==1)

doexecute(line,0);

else if (iscommand(line,"execback \0")==1)

doexecute(line,0);

else if (iscommand(line,"HELP\0")==1)

dohelp();

else if (iscommand(line,"help\0")==1)

dohelp();

else if (line[0]=='?')

dohelp();

else if (iscommand(line,"TYPE \0")==1)

dotype(line);

else if (iscommand(line,"type \0")==1)

dotype(line);

else if (iscommand(line,"KILL \0")==1)

dokill(line);

else if (iscommand(line,"kill \0")==1)

dokill(line);

else if (iscommand(line,"PS\0")==1)

dops();

else if (iscommand(line,"ps\0")==1)

dops();

else if (iscommand(line,"mkdir\0")==1)

domkdir(line);

else if (iscommand(line,"MKDIR\0")==1)

domkdir(line);

else if (iscommand(line,"ls\0")==1)

dols(line);

else if (iscommand(line,"LS\0")==1)

dols(line);

else

printstring("Command not found\r\n\0");

printstring("\r\n\0");

}

}