int execute_simple_command(simple_command *cmd) {
pid_t pid;
int status;
int result = 0;
if(cmd->builtin == BUILTIN_CD){
return execute_cd(cmd->tokens);
}
else if(cmd->builtin == BUILTIN_EXIT){
exit(0);
}
else if(cmd->builtin == 0){
if((pid = fork()) == -1){
perror("fork");
exit(EXIT_FAILURE);
}
else if(pid > 0){
waitpid(pid, &status, 0);
return status;
}
else if(pid == 0){
execute_nonbuiltin(cmd);
exit(0);
}
}
else{
printf("execute_simple error");
exit(EXIT_FAILURE);
}
return result;
}
/**
* Executes a simple command (no pipes).
*/
int execute_simple_command(simple_command *cmd) {
/**
* Check if the command is builtin.
* 1. If it is, then handle BUILTIN_CD (see execute_cd function provided)
* and BUILTIN_EXIT (simply exit with an appropriate exit status).
* 2. If it isn't, then you must execute the non-builtin command.
* - Fork a process to execute the nonbuiltin command
* (see execute_nonbuiltin function above).
* - The parent should wait for the child.
* (see wait man pages).
*/
int command_number;
/* Handle builtin commands. */
if((command_number = is_builtin(*(cmd->tokens)))) {
switch(command_number) {
case(BUILTIN_CD):
if(execute_cd(cmd->tokens) != EXIT_SUCCESS) {
printf("No such file or directory.\n");
}
return 0;
break;
case(BUILTIN_EXIT):
return -1;
break;
}
/* Handle nonbuiltin commands.
* Fork a process and use execute_nonbuiltin to execute the command.
*/
} else {
int pid;
if((pid = fork()) < 0) {
perror("fork");
return EXIT_FAILURE;
} else if (pid == 0) { //child
/* The exit status of the child process will be the return value
* of execute_nonbuiltin (if there is an error), or the exit
* status of the command exec'd.
*/
exit(execute_nonbuiltin(cmd));
} else { //parent
int status;
/* Wait for the command to return, then return its exit status*/
if(wait(&status) != -1) {
if(WIFEXITED(status)) {
return WEXITSTATUS(status);
} else {
return EXIT_FAILURE;
}
} else {
perror("wait");
return EXIT_FAILURE;
}
}
}
return EXIT_FAILURE;
}
static void
process_command(void)
{
int pos = -1;
char buffer[BUF_SIZE];
print_prompt();
do
{
char ch = getchar();
if (ch == 127)
{
/* Delete/BackSpace */
if (pos >= 0)
{
pos--;
printf("\b \b");
}
}
else if (ch == '\r' && pos < BUF_SIZE - 1)
{
/* Return */
buffer[++pos] = 0;
break;
}
else if (pos < BUF_SIZE - 2)
{
buffer[++pos] = ch;
putchar(buffer[pos]);
}
}
while (buffer[pos] != '\r');
buffer[pos] = 0;
newline();
if (pos == 0)
return;
/* Built-in commands */
if (strncmp(buffer, "cd", 2) == 0)
execute_cd(buffer);
else if (strncmp(buffer, "pwd", 3) == 0)
execute_pwd(buffer);
else if (strncmp(buffer, "exit", 4) == 0)
flag_exit = 1;
else
execute_command(buffer);
}
/**
* Executes a simple command (no pipes).
*/
int execute_simple_command(simple_command *cmd) {
/**
* TODO:
* Check if the command is builtin.
* 1. If it is, then handle BUILTIN_CD (see execute_cd function provided)
* and BUILTIN_EXIT (simply exit with an appropriate exit status).
* 2. If it isn't, then you must execute the non-builtin command.
* - Fork a process to execute the nonbuiltin command
* (see execute_nonbuiltin function above).
* - The parent should wait for the child.
* (see wait man pages).
*/
if(cmd->builtin != 0){
if(is_builtin(cmd->tokens[0]) == BUILTIN_CD){
execute_cd(cmd->tokens);
}else if(is_builtin(cmd->tokens[0]) == BUILTIN_EXIT){
return -1;
}
}else{
int r,status;
if ((r = fork()) == -1){ // fork failed
perror("fork");
exit(-1);
}
else if (r > 1){ // parent process
wait(&status);
} else if (r == 0){ // child process
execute_nonbuiltin(cmd);
exit(1);
}
}
return 0;
}
