#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <unistd.h>

#include "../internal/syscall.h"

/* Foreground-process-group ioctls (x86_64 _IO/_IOR derivations). */
#define VLIBC_PROC_TIOCGPGRP 0x540F
#define VLIBC_PROC_TIOCSPGRP 0x5410

/*
 * Process group and session control (POSIX base): setpgid, getpgrp,
 * setsid. The XSI/obsolescent extras (setpgrp, getpgid, getsid,
 * tcgetpgrp, tcsetpgrp) are gated at level 2 below.
 */

/*
 * setpgid: move pid (0 = the caller) into process group pgid (0 = pid's
 * own value). A process can change groups for itself and its children;
 * session leaders cannot change groups.
 */
int
setpgid(pid_t pid, pid_t pgid)
{
    return syscall_ret(__syscall2(SYS_setpgid, pid, pgid));
}

/*
 * getpgrp: the caller's process group.
 */
pid_t
getpgrp(void)
{
    return (pid_t)syscall_ret(__syscall0(SYS_getpgrp));
}

/*
 * setsid: make the caller the leader of a new session and process group,
 * detaching it from the controlling terminal. Returns the new session id
 * (the caller's pid), or -1 with errno EPERM when the caller is already
 * a process group leader.
 */
pid_t
setsid(void)
{
    return (pid_t)syscall_ret(__syscall0(SYS_setsid));
}

#if VLIBC_LEVEL_GE(2)

/* Level 2 (muslmimic): XSI and obsolescent session extras. */

/*
 * setpgrp (obsolescent): setpgid(0, 0) — the caller becomes the leader
 * of its own process group.
 */
int
setpgrp(void)
{
    return setpgid(0, 0);
}

/*
 * getpgid (XSI): the process group of pid (0 = the caller).
 */
pid_t
getpgid(pid_t pid)
{
    return (pid_t)syscall_ret(__syscall1(SYS_getpgid, pid));
}

/*
 * getsid (XSI): the session id of pid (0 = the caller).
 */
pid_t
getsid(pid_t pid)
{
    return (pid_t)syscall_ret(__syscall1(SYS_getsid, pid));
}

/*
 * tcgetpgrp (XSI): the foreground process group of the terminal on
 * fildes, or -1 with errno set (ENOTTY when fildes is not a terminal).
 */
pid_t
tcgetpgrp(int fildes)
{
    int pgrp = 0;

    if (syscall_ret(__syscall3(SYS_ioctl, fildes, VLIBC_PROC_TIOCGPGRP, (long)&pgrp)) < 0)
    {
        return (pid_t)-1;
    }
    return (pid_t)pgrp;
}

/*
 * tcsetpgrp (XSI): make pgid the foreground process group of the
 * terminal on fildes.
 */
int
tcsetpgrp(int fildes, pid_t pgid)
{
    return syscall_ret(__syscall3(SYS_ioctl, fildes, VLIBC_PROC_TIOCSPGRP, pgid));
}

#endif /* VLIBC_LEVEL_GE(2) */