/**
* forks a process and launches a program as child
*/
void launchJob(char *command[], char *file, int newDescriptor,
int executionMode)
{
pid_t pid;
pid = fork();
switch (pid) {
case -1:
perror("R-shell(fork)");
exit(EXIT_FAILURE);
break;
case 0:
/**
* we set the handling for job control signals back to the default.
*/
signal(SIGINT, SIG_DFL);
signal(SIGQUIT, SIG_DFL);
signal(SIGTSTP, SIG_DFL);
signal(SIGCHLD, &signalHandler_child);
signal(SIGTTIN, SIG_DFL);
usleep(20000); // fixes a synchronization bug. Needed for short commands like ls
setpgrp(); // make the child as new process group leader
if (executionMode == FOREGROUND)
tcsetpgrp(RSH_TERMINAL, getpid()); // if we want the process to be in foreground
if (executionMode == BACKGROUND)
printf("[%d] %d\n", ++numActiveJobs, (int) getpid()); // inform the user about the new job in bg
executeCommand(command, file, newDescriptor, executionMode);
exit(EXIT_SUCCESS);
break;
default:
setpgid(pid, pid); // we also make the child a new process group leader from here
// to avoid race conditions
jobsList = insertJob(pid, pid, *(command), file, (int) executionMode); // insert the job in the list
t_job* job = getJob(pid, BY_PROCESS_ID); // and get it as job object
if (executionMode == FOREGROUND) {
putJobForeground(job, FALSE); // put the job in foreground (if desired)
}
if (executionMode == BACKGROUND)
putJobBackground(job, FALSE); // put the job in background (if desired)
break;
}
}
void launchJob(char *command[], char *file, int newDescriptor,
int executionMode)
{
pid_t pid;
pid = fork();
switch (pid) {
case -1:
perror("MyShell");
exit(EXIT_FAILURE);
break;
case 0:
signal(SIGINT, SIG_DFL);
signal(SIGQUIT, SIG_DFL);
signal(SIGTSTP, SIG_DFL);
signal(SIGCHLD, &signalHandler_child);
signal(SIGTTIN, SIG_DFL);
usleep(20000);
setpgrp();
if (executionMode == FOREGROUND)
tcsetpgrp(MSH_TERMINAL, getpid());
if (executionMode == BACKGROUND)
printf("[%d] %d\n", ++numActiveJobs, (int) getpid());
executeCommand(command, file, newDescriptor, executionMode);
exit(EXIT_SUCCESS);
break;
default:
setpgid(pid, pid);
jobsList = insertJob(pid, pid, *(command), file, (int) executionMode);
t_job* job = getJob(pid, BY_PROCESS_ID);
if (executionMode == FOREGROUND) {
putJobForeground(job, FALSE);
}
if (executionMode == BACKGROUND)
putJobBackground(job, FALSE);
break;
}
}
int checkBuiltInCommands()
{
if (strcmp("exit", commandArgv[0]) == 0) {
puts("\nExiting. Thanks for using myShell!\n");
exit(EXIT_SUCCESS);
}
if (strcmp("cd", commandArgv[0]) == 0) {
//add_command_to_history(commandArgv[0]);
changeDirectory();
return 1;
}
/* if (strcmp("in", commandArgv[0]) == 0) {
launchJob(commandArgv + 2, *(commandArgv + 1), STDIN, FOREGROUND);
return 1;
}
if (strcmp("out", commandArgv[0]) == 0) {
launchJob(commandArgv + 2, *(commandArgv + 1), STDOUT, FOREGROUND);
return 1;
}*/
if (strcmp("bg", commandArgv[0]) == 0) {
//add_command_to_history(commandArgv[0]);
if (commandArgv[1] == NULL)
return 0;
/*if (strcmp("in", commandArgv[1]) == 0)
launchJob(commandArgv + 3, *(commandArgv + 2), STDIN, BACKGROUND);
else if (strcmp("out", commandArgv[1]) == 0)
launchJob(commandArgv + 3, *(commandArgv + 2), STDOUT, BACKGROUND);
else
launchJob(commandArgv + 1, "STANDARD", 0, BACKGROUND);*/
int jobId = (int) atoi(commandArgv[1]);
t_job* job = getJob(jobId, BY_JOB_ID);
if(job == NULL)
return 0;
if(job->status == SUSPENDED){
fprintf(stdout, "converting program from suspended to background wait status: ");
puts(job->name);
putJobBackground(job, TRUE);
//launchJob(job->name, "STANDARD", 0, BACKGROUND);
}
else{
putJobBackground(job, FALSE);
fprintf(stdout, "program already in a wait status.");
}
return 1;
}
if (strcmp("&", commandArgv[commandArgc-1]) == 0){ // commandArgv[1] for bg after file
//printf("%s", commandArgv[0]);
if (strcmp("&", commandArgv[0]) == 0) // commandArgv[0] for bg after file
return 0;
else{
//puts(commandArgv);
//printf("commandArgv: %p\n", commandArgv);
launchJob(commandArgv, "STANDARD", 0, BACKGROUND); // ommandArgv for bg after file
}
return 1;
}
else{
//printf("%s", commandArgv[0]);
}
if (strcmp("fg", commandArgv[0]) == 0) {
//add_command_to_history(commandArgv[0]);
if (commandArgv[1] == NULL)
return 0;
int jobId = (int) atoi(commandArgv[1]);
t_job* job = getJob(jobId, BY_JOB_ID);
if (job == NULL)
return 0;
if (job->status == SUSPENDED || job->status == WAITING_INPUT){
fprintf(stdout, "bringing program from background to run: ");
puts(job->name);
putJobForeground(job, TRUE);
}
else // status = BACKGROUND
putJobForeground(job, FALSE);
return 1;
}
if (strcmp("jobs", commandArgv[0]) == 0) {
//add_command_to_history(commandArgv[0]);
printJobs();
return 1;
}
if (strcmp("kill", commandArgv[0]) == 0)
{
//add_command_to_history(commandArgv[0]);
if (commandArgv[1] == NULL)
return 0;
char *nextCharPtr;
char testString[10];
strcpy(testString, commandArgv[1]);
char *test = testString;
if(strncmp("%", test, 1) == 0)
{
nextCharPtr = strtok(testString, "%");
killJob((atoi(nextCharPtr)));
return 1;
}
else{
killJobCredit((atoi(commandArgv[1])));
return 1;
}
}
/*if(strcmp("!1", commandArgv[0]) == 0){
char *cP;
int number;
cP = strtok(commandArgv[0], "!");
number = atoi(cP)-1;
char historyPoint[60];
char *hisString;
char *newCommand[10];
int i;
for(i = 0; i < 60; i++){
historyPoint[i] = (char)history[number][i];
}
hisString = strtok(historyPoint, "");
printf("%s\n", hisString);
//historyPoint = history[number];
//printf("%s\n", historyPoint);
newCommand[0] = hisString;
//printf("commandArgv: %s\n", commandArgv[0]);
commandArgv[0] = newCommand[0];
//printf("new commandArgv: %s\n", commandArgv[0]);
//printf("%s\n", newCommand[0]);
//launchJob(newCommand[0], "STANDARD", 0, FOREGROUND);
//executeCommand(commandArgv[0], "STANDARD", 0, FOREGROUND);
return 1;
}*/
if(strcmp("history", commandArgv[0]) == 0)
{
int index;
int column;
int count = 1;
printf("Command History List\n");
printf("%d: ", count);
for(index = 0; index < 10; index++){
for(column = 0; column < 55; column++){
fprintf(stdout, "%c", history[index][column]);
}
count++;
//printf("%d: ", count);
if(count <= 10){
printf("\n");
printf("%d: ", count);
}
if(count == 11)
printf("\n");
//count++;
}
return 1;
}
if(strcmp("help", commandArgv[0]) == 0)
{
printf("Help Menu\n");
printf("The functionality of this shell is as follows:\n\n");
printf("The execution of simple normal shell operations such as cat, more, echo, any user-defined program, etc. will\n");
printf("operate exactly as they would in the bash shell.\n");
printf("The built-in commands ls, cd, ps and pwd will operate just as they would in the bash shell as well.\n");
printf("To start a program in the background simply append the & symbol such as, ./program &\n");
printf("The command jobs can be used to list the processes that are currently running in the background of your shell.\n");
printf("If a program has been suspended, such as the user entering CTRL-Z, you can background the job to wait status using\n");
printf("the command bg <job number> e.g. bg 1\n");
printf("If a job is in the background, either in wait-status or suspended, it can be brought to the foreground by using the\n");
printf("command fg <job number> e.g. fg 1\n");
printf("A job can be killed using the command kill %<job number> such as kill %1 or using the pid number, kill <pid number>\n");
printf("You can obtain the pid number of a job from the jobs list or the ps command.\n");
printf("Simple input/output redirection is accomplished as follows:\n");
printf("./a.out < input -- would run program a.out with input from file input and would write all output to stdout\n");
printf("./a.out > output -- would run program a.out with output of program sent to the created file output\n");
printf("./a.out < input > output -- would run program a.out with input from file input and would write output to the created file output.\n");
printf("./a.out >> output -- would run program a.out with output of program appended to the end of the previously created file output.\n");
printf("./a.out < input >> output -- would run program a.out with input from file input and append output to the end of the previously\n");
printf("created file output.\n");
printf("Simple pipe functionality has also been implemented in this shell. An example is as follows:\n");
printf("who | wc -- would run command who and pipe output to the word count process\n");
printf("To see a list of previously entered commands type history at the shell prompt, only ten commands are held in history per shell execution.\n");
printf("To execute a previous command listed in history type !<command number> e.g. !1 at the shell prompt.");
printf("To exit the shell program type exit at the shell prompt.\n\n");
printf("End of Help Menu\n");
return 1;
}
//int i;
////for( i=0;i<=commandArgc;i++)
//{
//char *str;
//strcpy(str,commandArgv);
if( commandArgc == 3 )
{
if(strcmp("|", commandArgv[1]) == 0 )
{
pipelining(2);
return 1;
}
else if(strcmp("<", commandArgv[commandArgc-2]) == 0){
int in;
int i = 0;
i = fork();
if(i == 0){
in = open(commandArgv[2], O_RDONLY);
dup2(in, 0);
close(in);
executeCommand(commandArgv, "STANDARD", 0, FOREGROUND);
//puts("test statement 1");
dup2(0, 0);
//printf("test statement 2");
}else{
waitpid(getpid(), NULL, 0);
close(in);
}
return 1;
}
else if(strcmp(">", commandArgv[commandArgc-2]) == 0){
int out;
int i = 0;
i = fork();
if(i == 0){
out = open(commandArgv[2], O_WRONLY | O_TRUNC | O_CREAT, S_IRUSR | S_IRGRP | S_IWGRP | S_IWUSR);
dup2(out, 1);
close(out);
executeCommand(commandArgv, "STANDARD", 0, FOREGROUND);
//printf("test statement 3");
dup2(1, 1);
//printf("test statement 4");
}else{
waitpid(getpid(), NULL, 0);
close(out);
}
return 1;
}
else if(strcmp(">>", commandArgv[commandArgc-2]) == 0){
int out;
int i = 0;
int offset;
i = fork();
if(i == 0){
out = open(commandArgv[2], O_WRONLY | O_APPEND);
offset = lseek(out, 1, SEEK_END);
dup2(out, 1);
close(out);
executeCommandAppend(commandArgv, "STANDARD", 0, FOREGROUND);
dup2(1, 1);
}else{
waitpid(getpid(), NULL, 0);
close(out);
}
return 1;
}
}
if( commandArgc > 3 )
{
if(strcmp(">", commandArgv[commandArgc-2]) == 0){
int in;
int out;
int i = 0;
i = fork();
if(i == 0){
in = open(commandArgv[2], O_RDONLY);
out = open(commandArgv[4], O_WRONLY | O_TRUNC | O_CREAT, S_IRUSR | S_IRGRP | S_IWGRP | S_IWUSR);
dup2(in, 0);
dup2(out, 1);
close(in);
close(out);
executeCommand(commandArgv, "STANDARD", 0, FOREGROUND);
dup2(0, 0);
dup2(1, 1);
}else{
waitpid(getpid(), NULL, 0);
close(in);
close(out);
}
return 1;
}
else if(strcmp("|", commandArgv[commandArgc-2]) == 0 )
{
//puts("works");
//printf("%d",commandArgc);
pipelining(commandArgc-1);
return 1;
}
else if(strcmp(">>", commandArgv[commandArgc-2]) == 0){
int in;
int out;
int offset;
int i = 0;
i = fork();
if(i == 0){
in = open(commandArgv[2], O_RDONLY);
out = open(commandArgv[4], O_WRONLY | O_APPEND);
offset = lseek(out, 1, SEEK_END);
dup2(in, 0);
dup2(out, 1);
close(in);
close(out);
executeCommandAppend(commandArgv, "STANDARD", 0, FOREGROUND);
dup2(0, 0);
dup2(1, 1);
}else{
waitpid(getpid(), NULL, 0);
close(in);
close(out);
}
return 1;
}
}
//break;
//}
return 0;
}