mirror of
https://git.tartarus.org/simon/putty.git
synced 2025-01-10 09:58:01 +00:00
459 lines
9.5 KiB
C
459 lines
9.5 KiB
C
#define _XOPEN_SOURCE
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#define _XOPEN_SOURCE_EXTENDED
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#include <features.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <signal.h>
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#include <fcntl.h>
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#include <termios.h>
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#include <grp.h>
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#include <utmp.h>
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#include <pwd.h>
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#include <time.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <sys/ioctl.h>
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#include "putty.h"
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#ifndef FALSE
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#define FALSE 0
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#endif
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#ifndef TRUE
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#define TRUE 1
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#endif
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#ifndef UTMP_FILE
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#define UTMP_FILE "/var/run/utmp"
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#endif
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#ifndef WTMP_FILE
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#define WTMP_FILE "/var/log/wtmp"
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#endif
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#ifndef LASTLOG_FILE
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#ifdef _PATH_LASTLOG
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#define LASTLOG_FILE _PATH_LASTLOG
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#else
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#define LASTLOG_FILE "/var/log/lastlog"
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#endif
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#endif
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/*
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* Set up a default for vaguely sane systems. The idea is that if
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* OMIT_UTMP is not defined, then at least one of the symbols which
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* enable particular forms of utmp processing should be, if only so
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* that a link error can warn you that you should have defined
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* OMIT_UTMP if you didn't want any. Currently HAVE_PUTUTLINE is
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* the only such symbol.
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*/
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#ifndef OMIT_UTMP
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#if !defined HAVE_PUTUTLINE
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#define HAVE_PUTUTLINE
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#endif
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#endif
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int pty_master_fd;
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static int pty_stamped_utmp = 0;
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static int pty_child_pid;
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static sig_atomic_t pty_child_dead;
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#ifndef OMIT_UTMP
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static struct utmp utmp_entry;
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#endif
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char **pty_argv;
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int pty_child_is_dead(void)
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{
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return pty_child_dead;
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}
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static void pty_size(void);
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static void setup_utmp(char *ttyname)
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{
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#ifndef OMIT_UTMP
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#ifdef HAVE_LASTLOG
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struct lastlog lastlog_entry;
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FILE *lastlog;
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#endif
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struct passwd *pw;
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char *location;
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FILE *wtmp;
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if (!cfg.stamp_utmp)
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return;
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pw = getpwuid(getuid());
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location = get_x_display();
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memset(&utmp_entry, 0, sizeof(utmp_entry));
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utmp_entry.ut_type = USER_PROCESS;
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utmp_entry.ut_pid = getpid();
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strncpy(utmp_entry.ut_line, ttyname+5, lenof(utmp_entry.ut_line));
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strncpy(utmp_entry.ut_id, ttyname+8, lenof(utmp_entry.ut_id));
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strncpy(utmp_entry.ut_user, pw->pw_name, lenof(utmp_entry.ut_user));
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strncpy(utmp_entry.ut_host, location, lenof(utmp_entry.ut_host));
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time(&utmp_entry.ut_time);
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#if defined HAVE_PUTUTLINE
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utmpname(UTMP_FILE);
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setutent();
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pututline(&utmp_entry);
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endutent();
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#endif
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if ((wtmp = fopen(WTMP_FILE, "a")) != NULL) {
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fwrite(&utmp_entry, 1, sizeof(utmp_entry), wtmp);
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fclose(wtmp);
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}
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#ifdef HAVE_LASTLOG
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memset(&lastlog_entry, 0, sizeof(lastlog_entry));
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strncpy(lastlog_entry.ll_line, ttyname+5, lenof(lastlog_entry.ll_line));
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strncpy(lastlog_entry.ll_host, location, lenof(lastlog_entry.ll_host));
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time(&lastlog_entry.ll_time);
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if ((lastlog = fopen(LASTLOG_FILE, "r+")) != NULL) {
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fseek(lastlog, sizeof(lastlog_entry) * getuid(), SEEK_SET);
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fwrite(&lastlog_entry, 1, sizeof(lastlog_entry), lastlog);
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fclose(lastlog);
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}
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#endif
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pty_stamped_utmp = 1;
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#endif
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}
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static void cleanup_utmp(void)
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{
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#ifndef OMIT_UTMP
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FILE *wtmp;
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if (!cfg.stamp_utmp || !pty_stamped_utmp)
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return;
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utmp_entry.ut_type = DEAD_PROCESS;
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memset(utmp_entry.ut_user, 0, lenof(utmp_entry.ut_user));
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time(&utmp_entry.ut_time);
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if ((wtmp = fopen(WTMP_FILE, "a")) != NULL) {
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fwrite(&utmp_entry, 1, sizeof(utmp_entry), wtmp);
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fclose(wtmp);
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}
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memset(utmp_entry.ut_line, 0, lenof(utmp_entry.ut_line));
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utmp_entry.ut_time = 0;
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#if defined HAVE_PUTUTLINE
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utmpname(UTMP_FILE);
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setutent();
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pututline(&utmp_entry);
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endutent();
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#endif
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pty_stamped_utmp = 0; /* ensure we never double-cleanup */
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#endif
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}
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static void sigchld_handler(int signum)
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{
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pid_t pid;
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int status;
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pid = waitpid(-1, &status, WNOHANG);
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if (pid == pty_child_pid && (WIFEXITED(status) || WIFSIGNALED(status)))
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pty_child_dead = TRUE;
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}
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static void fatal_sig_handler(int signum)
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{
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signal(signum, SIG_DFL);
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cleanup_utmp();
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setuid(getuid());
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raise(signum);
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}
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/*
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* Called to set up the pty.
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*
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* Returns an error message, or NULL on success.
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*
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* Also places the canonical host name into `realhost'. It must be
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* freed by the caller.
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*/
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static char *pty_init(char *host, int port, char **realhost, int nodelay)
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{
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int slavefd;
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char name[FILENAME_MAX];
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pid_t pid, pgrp;
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#ifdef BSD_PTYS
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{
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const char chars1[] = "pqrstuvwxyz";
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const char chars2[] = "0123456789abcdef";
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const char *p1, *p2;
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char master_name[20];
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for (p1 = chars1; *p1; p1++)
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for (p2 = chars2; *p2; p2++) {
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sprintf(master_name, "/dev/pty%c%c", *p1, *p2);
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pty_master_fd = open(master_name, O_RDWR);
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if (pty_master_fd >= 0) {
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if (geteuid() == 0 ||
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access(master_name, R_OK | W_OK) == 0)
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goto got_one;
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close(pty_master_fd);
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}
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}
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/* If we get here, we couldn't get a tty at all. */
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fprintf(stderr, "pterm: unable to open a pseudo-terminal device\n");
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exit(1);
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got_one:
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strcpy(name, master_name);
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name[5] = 't'; /* /dev/ptyXX -> /dev/ttyXX */
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}
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#else
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pty_master_fd = open("/dev/ptmx", O_RDWR);
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if (pty_master_fd < 0) {
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perror("/dev/ptmx: open");
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exit(1);
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}
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if (grantpt(pty_master_fd) < 0) {
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perror("grantpt");
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exit(1);
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}
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if (unlockpt(pty_master_fd) < 0) {
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perror("unlockpt");
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exit(1);
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}
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name[FILENAME_MAX-1] = '\0';
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strncpy(name, ptsname(pty_master_fd), FILENAME_MAX-1);
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#endif
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/*
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* Trap as many fatal signals as we can in the hope of having
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* the best chance to clean up utmp before termination.
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*/
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signal(SIGHUP, fatal_sig_handler);
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signal(SIGINT, fatal_sig_handler);
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signal(SIGQUIT, fatal_sig_handler);
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signal(SIGILL, fatal_sig_handler);
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signal(SIGABRT, fatal_sig_handler);
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signal(SIGFPE, fatal_sig_handler);
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signal(SIGPIPE, fatal_sig_handler);
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signal(SIGALRM, fatal_sig_handler);
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signal(SIGTERM, fatal_sig_handler);
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signal(SIGSEGV, fatal_sig_handler);
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signal(SIGUSR1, fatal_sig_handler);
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signal(SIGUSR2, fatal_sig_handler);
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#ifdef SIGBUS
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signal(SIGBUS, fatal_sig_handler);
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#endif
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#ifdef SIGPOLL
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signal(SIGPOLL, fatal_sig_handler);
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#endif
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#ifdef SIGPROF
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signal(SIGPROF, fatal_sig_handler);
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#endif
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#ifdef SIGSYS
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signal(SIGSYS, fatal_sig_handler);
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#endif
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#ifdef SIGTRAP
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signal(SIGTRAP, fatal_sig_handler);
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#endif
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#ifdef SIGVTALRM
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signal(SIGVTALRM, fatal_sig_handler);
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#endif
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#ifdef SIGXCPU
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signal(SIGXCPU, fatal_sig_handler);
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#endif
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#ifdef SIGXFSZ
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signal(SIGXFSZ, fatal_sig_handler);
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#endif
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#ifdef SIGIO
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signal(SIGIO, fatal_sig_handler);
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#endif
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/* Also clean up utmp on normal exit. */
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atexit(cleanup_utmp);
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setup_utmp(name);
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/*
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* Fork and execute the command.
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*/
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pid = fork();
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if (pid < 0) {
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perror("fork");
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exit(1);
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}
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if (pid == 0) {
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int i;
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/*
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* We are the child.
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*/
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slavefd = open(name, O_RDWR);
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if (slavefd < 0) {
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perror("slave pty: open");
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exit(1);
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}
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#ifdef BSD_PTYS
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/* We need to chown/chmod the /dev/ttyXX device. */
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{
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struct group *gp = getgrnam("tty");
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fchown(slavefd, getuid(), gp ? gp->gr_gid : -1);
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fchmod(slavefd, 0600);
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}
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#endif
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close(pty_master_fd);
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close(0);
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close(1);
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close(2);
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fcntl(slavefd, F_SETFD, 0); /* don't close on exec */
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dup2(slavefd, 0);
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dup2(slavefd, 1);
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dup2(slavefd, 2);
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setsid();
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ioctl(slavefd, TIOCSCTTY, 1);
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pgrp = getpid();
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tcsetpgrp(slavefd, pgrp);
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setpgrp();
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close(open(name, O_WRONLY, 0));
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setpgrp();
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/* In case we were setgid-utmp or setuid-root, drop privs. */
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setgid(getgid());
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setuid(getuid());
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/* Close everything _else_, for tidiness. */
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for (i = 3; i < 1024; i++)
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close(i);
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{
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char term_env_var[10 + sizeof(cfg.termtype)];
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sprintf(term_env_var, "TERM=%s", cfg.termtype);
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putenv(term_env_var);
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}
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if (pty_argv)
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execvp(pty_argv[0], pty_argv);
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else {
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char *shell = getenv("SHELL");
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char *shellname;
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if (cfg.login_shell) {
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char *p = strrchr(shell, '/');
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shellname = smalloc(2+strlen(shell));
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p = p ? p+1 : shell;
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sprintf(shellname, "-%s", p);
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} else
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shellname = shell;
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execl(getenv("SHELL"), shellname, NULL);
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}
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/*
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* If we're here, exec has gone badly foom.
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*/
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perror("exec");
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exit(127);
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} else {
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close(slavefd);
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pty_child_pid = pid;
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pty_child_dead = FALSE;
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signal(SIGCHLD, sigchld_handler);
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}
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return NULL;
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}
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/*
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* Called to send data down the pty.
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*/
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static int pty_send(char *buf, int len)
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{
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while (len > 0) {
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int ret = write(pty_master_fd, buf, len);
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if (ret < 0) {
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perror("write pty master");
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exit(1);
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}
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buf += ret;
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len -= ret;
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}
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return 0;
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}
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/*
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* Called to query the current socket sendability status.
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*/
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static int pty_sendbuffer(void)
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{
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return 0;
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}
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/*
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* Called to set the size of the window
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*/
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static void pty_size(void)
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{
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struct winsize size;
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size.ws_row = (unsigned short)rows;
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size.ws_col = (unsigned short)cols;
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size.ws_xpixel = (unsigned short) cols * font_dimension(0);
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size.ws_ypixel = (unsigned short) rows * font_dimension(1);
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ioctl(pty_master_fd, TIOCSWINSZ, (void *)&size);
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return;
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}
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/*
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* Send special codes.
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*/
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static void pty_special(Telnet_Special code)
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{
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/* Do nothing! */
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return;
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}
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static Socket pty_socket(void)
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{
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return NULL; /* shouldn't ever be needed */
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}
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static int pty_sendok(void)
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{
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return 1;
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}
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static void pty_unthrottle(int backlog)
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{
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/* do nothing */
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}
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static int pty_ldisc(int option)
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{
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return 0; /* neither editing nor echoing */
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}
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static int pty_exitcode(void)
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{
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/* Shouldn't ever be required */
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return 0;
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}
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Backend pty_backend = {
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pty_init,
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pty_send,
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pty_sendbuffer,
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pty_size,
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pty_special,
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pty_socket,
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pty_exitcode,
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pty_sendok,
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pty_ldisc,
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pty_unthrottle,
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1
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};
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