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#include "eval.h"
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <ctype.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <errno.h>
#include <iostream>
#include <vector>
#include <string>
using namespace std;
namespace ov4
{
/*
* 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)
{
char arg[MAXARGS][MAXLINE];
char *argv[MAXARGS];
for (int i = 0 ; i < MAXARGS; i++)
{
argv[i] = &arg[i][0];
}
int ground = parseline(cmdline, argv);
if (argv[0] == nullptr) return;
if (exe_bultin_command(argv)) return;
// block_io signals can stop shell
// when child is at foreground, parent shell is at background
sigprocmask(SIG_BLOCK, &block_io, nullptr);
sigset_t prev;
block_all(&prev);
string cmd = find_cmd(argv[0]);
const char* cmd_c = cmd.c_str();
shell_pgid = getpgid(0);
pid_t pid = fork();
if (pid == 0) // child
{
setpgid(0, 0);
if (!ground) // foreground
tcsetpgrp(tty_fd, getpgrp());
sigprocmask(SIG_SETMASK, &prev, nullptr);
// program inside execve may use SIGTTIN/SIGTTOU so just restore in child
sigprocmask(SIG_UNBLOCK, &block_io, nullptr);
execve(cmd_c, argv, environ);
safe_print(cmdline, true);
safe_print(": Command not found\n");
exit(-1); // if no command is found
}
// parent
if (!ground) // foreground
{
addjob(jobs, pid, FG, cmdline);
sigset_t prev_with_sigchld_blocked = prev;
sigaddset(&prev_with_sigchld_blocked, SIGCHLD);
sigprocmask(SIG_SETMASK, &prev_with_sigchld_blocked, NULL);
waitfg(pid);
sigprocmask(SIG_SETMASK, &prev, NULL);
}
else // background
{
addjob(jobs, pid, BG, cmdline);
sigprocmask(SIG_SETMASK, &prev, NULL);
cout << "[" << pid2jid(pid) << "] (" << pid << ") " << cmdline;
}
return;
}
}
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