int buildin(char * s){
int rt = 0;
//exit
if(strcmp("exit",s) == 0){
rt = 1;
exit(0);
}
//hisotry
if(strcmp("history",s) == 0){
rt = 1;
history();
}
//exclamation
if (*s == '!') {
rt = 1;
int id = 0;
IDcounter--;
if (IDcounter < 0) {
IDcounter = 0;
}
if (*(s+1) == '\0') {
id = IDcounter;
char* redo = exclamation(id);
buildin(redo);
}
else{
id = atoi(s+1);
char* redo = exclamation(id);
buildin(redo);
}
}
return rt;
}
/*
* eval - Evaluate the command line that the user has just typed in
*
* If the user has requested a built-in command (quit, jobs, bg or fg)
* then execute it immediately. Otherwise, fork a child process and
* run the job in the context of the child. If the job is running in
* the foreground, wait for it to terminate and then return. Note:
* each child process must have a unique process group ID so that our
* background children don't receive SIGINT (SIGTSTP) from the kernel
* when we type ctrl-c (ctrl-z) at the keyboard.
*/
void eval(char *cmdline) {
int bg; /* should the job run in bg or fg? */
struct cmdline_tokens tok;
int pid;
sigset_t mask;
/* Parse command line */
bg = parseline(cmdline, &tok);
if (bg == -1)
return; /* parsing error */
if (tok.argv[0] == NULL)
return; /* ignore empty lines */
if(buildin(&tok) == 0) {
/* empty mask and add SIGCHLD, SIGINT and SIGTSTP to mask */
if(sigemptyset(&mask) == -1)
return;
if(sigaddset(&mask, SIGCHLD) == -1)
return;
if(sigaddset(&mask, SIGINT) == -1)
return;
if(sigaddset(&mask, SIGTSTP) == -1)
return;
/* to avoid race condition, we first block the signals in father process */
if(sigprocmask(SIG_BLOCK, &mask, NULL) == -1)
return;
if((pid = fork()) == 0){
if(sigprocmask(SIG_UNBLOCK, &mask, NULL) == -1)
return;
redirect_io(tok.infile, tok.outfile);
if(setpgid(0, 0) == -1)
return;
if(execve(tok.argv[0], tok.argv, environ) < 0){
fprintf(stderr, "%s: Command not found. \n", tok.argv[0]);
exit(0);
}
}
if(bg){
if(addjob(job_list, pid, BG, cmdline) == 0)
return;
} else {
if(addjob(job_list, pid, FG, cmdline) == 0)
return;
}
/* since we have already added the child processes into job_list, we unblock the signals here */
if(sigprocmask(SIG_UNBLOCK, &mask, NULL) == -1)
return;
if(bg) {
printf("[%d] (%d) %s\n", getjobpid(job_list, pid)->jid, pid, cmdline);
} else {
sigset_t temp_mask;
sigemptyset(&temp_mask);
while(fgpid(job_list) != 0 &&
getjobpid(job_list, pid)->state != ST){
sigsuspend(&temp_mask);
}
}
}
return;
}
int main (int argc, char* argv[]) {
lis = (process *)malloc(20*sizeof(process));
int batch = 0;
input = stdin;
output = STDOUT_FILENO;
if(argc == 2){
batch = 1;
input = fopen(argv[1], "r");
if (input == NULL) {
char error_message[30] = "An error has occurred\n";
write(STDERR_FILENO, error_message, strlen(error_message));
exit(1);
}
}
if (argc > 2) {
char error_message[30] = "An error has occurred\n";
write(STDERR_FILENO, error_message, strlen(error_message));
}
while(1){
char userInput[512];
process* temp;
temp = (process* ) malloc(sizeof(process));
//printf("%s", "mysh # ");
if (batch < 1) {
write(1, "mysh # ", strlen("mysh # "));
}
//scanf("%[^\n]",userInput);
if(fgets(userInput, sizeof(userInput), input) == NULL){
if(feof(input)){
break;
}else{
char error_message[30] = "An error has occurred\n";
write(STDERR_FILENO, error_message, strlen(error_message));
}
}
if(batch == 1){
write(1, userInput, strlen(userInput));
}
//fgets(userInput, sizeof(userInput), stdin);
//truncate the newline character
size_t ln = strlen(userInput) - 1;
if (userInput[ln] == '\n')
userInput[ln] = '\0';
//store in process history
temp->id = IDcounter+1;
strcpy(temp->command,userInput);
lis[IDcounter%20] = *temp;
IDcounter++;
//truncate space in front and after
char* trim_input = truncate_space(userInput);
//printf("%d",strcmp("history\n",userInput));
if(buildin(trim_input)==0){
int flag = 1;
char * filename;
char * ptr;
char * star;
star = trim_input;
ptr = trim_input;
int redirect = 0;
int j;
for (j = 0; j < strlen(trim_input); j++) {
if (*ptr == ' ' && *(ptr-1) != ' ') {
flag++;
}
if (*ptr == '>') {
filename = ptr+1;
filename = truncate_space(filename);
redirect = 1;
*ptr = '\0';
ptr = strlen(trim_input);
}
ptr++;
}
if (redirect == 1) {
FILE* new = open(filename, O_WRONLY|O_CREAT|O_TRUNC, S_IRWXU);
fflush(stdout);
int b = dup(1);
dup2(new, 1);
//close(new);
}
trim_input = truncate_space(userInput);
star = trim_input;
ptr = trim_input+1;
int q;
for (q = 0; q < strlen(trim_input); q++) {
if (*ptr == ' ' && *(ptr-1) != ' ') {
flag++;
}
ptr++;
}
ptr = trim_input+1;
pid_t child_pid;
char* child_argv[flag+1];
int k = 0;
int strlength = strlen(trim_input);
for (ptr; ptr < strlength+trim_input+1; ptr++) {
//printf("%d", strlen(trim_input));
if(*ptr != '>'){
if (*ptr == ' ' && (*(ptr-1) != ' ') && (*(ptr-1) != '\0')) {
*ptr = '\0';
child_argv[k] = star;
//printf("%s", star);
star = ptr+1;
k++;
}
else if (*ptr == '\0') {
//printf("/%s", star);
child_argv[k] = star;
}
}
}
child_argv[flag] = NULL;
int status;
if((child_pid = fork())< 0){
char error_message[30] = "An error has occurred\n";
write(STDERR_FILENO, error_message, strlen(error_message));
exit(1);
}
else if(child_pid == 0){
if(execvp(child_argv[0], child_argv) < 0 ){
char error_message[30] = "An error has occurred\n";
write(STDERR_FILENO, error_message, strlen(error_message));
exit(1);
}
}
else{
wait(&status);
}
}
/**
* parse command
* return the number of command on success
* return -1 on failed
*/
int parse_command(void) {
/*char *cp = cmdline;
char *avp = avline;
int i = 0;
while (*cp != '\0') {
while (*cp==' ' || *cp=='\t') {
// left trim
cp++;
}
if (*cp=='\0' || *cp=='\n') {
break;
}
cmd.args[i] = avp;
// parse args
while (*cp != '\0'
&& *cp != ' '
&& *cp != '\t'
&& *cp != '\n') {
*avp++ = *cp++;
}
*avp++ = '\0';
printf("[%s]\n", cmd.args[i]);
i++;
}
return 0;*/
/* a example command: cat < test.txt
| grep -n public > test2.txt & */
if (check("\n")) {
return 0;
}
if (buildin()) {
return 0;
}
// 1. parse a simple command
get_command(0);
// 2. judge the input redirect
if (check("<")) {
getname(infile);
}
// 3. judge the pipe
int i;
for (i=1; i<PIPELINE; i++) {
if (check("|")) {
get_command(i);
} else {
break;
}
}
// 4. judghe the output redirect
if (check(">")) {
if (check(">")) {
append = 1;
}
getname(outfile);
}
// 5. judge the background job
if (check("&")) {
backgnd = 1;
}
// 6. judge the end of a command
if (check("\n")) {
cmd_count = i;
return cmd_count;
} else {
fprintf(stderr, "command line syntax err");
return -1;
}
}
