#define _XOPEN_SOURCE
#define _XOPEN_SOURCE_EXTENDED
#include <features.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <fcntl.h>
#include <termios.h>
#include <grp.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/ioctl.h>
#include "putty.h"
#ifndef FALSE
#define FALSE 0
#endif
#ifndef TRUE
#define TRUE 1
#endif
int pty_master_fd;
static int pty_child_pid;
static sig_atomic_t pty_child_dead;
char **pty_argv;
int pty_child_is_dead(void)
{
return pty_child_dead;
}
static void pty_size(void);
static void sigchld_handler(int signum)
{
pid_t pid;
int status;
pid = waitpid(-1, &status, WNOHANG);
if (pid == pty_child_pid && (WIFEXITED(status) || WIFSIGNALED(status)))
pty_child_dead = TRUE;
}
/*
* Called to set up the pty.
*
* Returns an error message, or NULL on success.
*
* Also places the canonical host name into `realhost'. It must be
* freed by the caller.
*/
static char *pty_init(char *host, int port, char **realhost, int nodelay)
{
int slavefd;
char name[FILENAME_MAX];
pid_t pid, pgrp;
#ifdef BSD_PTYS
{
const char chars1[] = "pqrstuvwxyz";
const char chars2[] = "0123456789abcdef";
const char *p1, *p2;
char master_name[20];
for (p1 = chars1; *p1; p1++)
for (p2 = chars2; *p2; p2++) {
sprintf(master_name, "/dev/pty%c%c", *p1, *p2);
pty_master_fd = open(master_name, O_RDWR);
if (pty_master_fd >= 0) {
if (geteuid() == 0 ||
access(master_name, R_OK | W_OK) == 0)
goto got_one;
close(pty_master_fd);
}
}
/* If we get here, we couldn't get a tty at all. */
fprintf(stderr, "pterm: unable to open a pseudo-terminal device\n");
exit(1);
got_one:
strcpy(name, master_name);
name[5] = 't'; /* /dev/ptyXX -> /dev/ttyXX */
}
#else
pty_master_fd = open("/dev/ptmx", O_RDWR);
if (pty_master_fd < 0) {
perror("/dev/ptmx: open");
exit(1);
}
if (grantpt(pty_master_fd) < 0) {
perror("grantpt");
exit(1);
}
if (unlockpt(pty_master_fd) < 0) {
perror("unlockpt");
exit(1);
}
name[FILENAME_MAX-1] = '\0';
strncpy(name, ptsname(pty_master_fd), FILENAME_MAX-1);
#endif
/*
* Fork and execute the command.
*/
pid = fork();
if (pid < 0) {
perror("fork");
exit(1);
}
if (pid == 0) {
int i;
/*
* We are the child.
*/
slavefd = open(name, O_RDWR);
if (slavefd < 0) {
perror("slave pty: open");
exit(1);
}
#ifdef BSD_PTYS
/* We need to chown/chmod the /dev/ttyXX device. */
{
struct group *gp = getgrnam("tty");
fchown(slavefd, getuid(), gp ? gp->gr_gid : -1);
fchmod(slavefd, 0600);
}
#endif
close(pty_master_fd);
close(0);
close(1);
close(2);
fcntl(slavefd, F_SETFD, 0); /* don't close on exec */
dup2(slavefd, 0);
dup2(slavefd, 1);
dup2(slavefd, 2);
setsid();
ioctl(slavefd, TIOCSCTTY, 1);
pgrp = getpid();
tcsetpgrp(slavefd, pgrp);
setpgrp();
close(open(name, O_WRONLY, 0));
setpgrp();
/* In case we were setgid-utmp or setuid-root, drop privs. */
setgid(getgid());
setuid(getuid());
/* Close everything _else_, for tidiness. */
for (i = 3; i < 1024; i++)
close(i);
{
char term_env_var[10 + sizeof(cfg.termtype)];
sprintf(term_env_var, "TERM=%s", cfg.termtype);
putenv(term_env_var);
}
if (pty_argv)
execvp(pty_argv[0], pty_argv);
else
execl(getenv("SHELL"), getenv("SHELL"), NULL);
/*
* If we're here, exec has gone badly foom.
*/
perror("exec");
exit(127);
} else {
close(slavefd);
pty_child_pid = pid;
pty_child_dead = FALSE;
signal(SIGCHLD, sigchld_handler);
}
return NULL;
}
/*
* Called to send data down the pty.
*/
static int pty_send(char *buf, int len)
{
while (len > 0) {
int ret = write(pty_master_fd, buf, len);
if (ret < 0) {
perror("write pty master");
exit(1);
}
buf += ret;
len -= ret;
}
return 0;
}
/*
* Called to query the current socket sendability status.
*/
static int pty_sendbuffer(void)
{
return 0;
}
/*
* Called to set the size of the window
*/
static void pty_size(void)
{
struct winsize size;
size.ws_row = (unsigned short)rows;
size.ws_col = (unsigned short)cols;
ioctl(pty_master_fd, TIOCSWINSZ, (void *)&size);
return;
}
/*
* Send special codes.
*/
static void pty_special(Telnet_Special code)
{
/* Do nothing! */
return;
}
static Socket pty_socket(void)
{
return NULL; /* shouldn't ever be needed */
}
static int pty_sendok(void)
{
return 1;
}
static void pty_unthrottle(int backlog)
{
/* do nothing */
}
static int pty_ldisc(int option)
{
return 0; /* neither editing nor echoing */
}
static int pty_exitcode(void)
{
/* Shouldn't ever be required */
return 0;
}
Backend pty_backend = {
pty_init,
pty_send,
pty_sendbuffer,
pty_size,
pty_special,
pty_socket,
pty_exitcode,
pty_sendok,
pty_ldisc,
pty_unthrottle,
1
};