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putty-source/contrib/cygtermd/pty.c
Simon Tatham ddfca43402 Fix a controlling-terminal bug reported by Anthony Heading: Cygwin
doesn't have TIOCSCTTY, so my attempt to set the ctty of the child
process isn't doing anything, and only works by chance when you run
bash because bash does the thing that _will_ set the ctty, namely
opening the terminal file again without O_NOCTTY. So now we do that
too.

[originally from svn r9638]
2012-08-28 17:42:47 +00:00

203 lines
4.4 KiB
C

/*
* pty.c - pseudo-terminal handling
*/
#define _XOPEN_SOURCE
#include <features.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <unistd.h>
#include <fcntl.h>
#include <termios.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <pwd.h>
#include "pty.h"
#include "malloc.h"
static char ptyname[FILENAME_MAX];
int master = -1;
void pty_preinit(void)
{
/*
* Allocate the pty.
*/
master = open("/dev/ptmx", O_RDWR);
if (master < 0) {
perror("/dev/ptmx: open");
exit(1);
}
if (grantpt(master) < 0) {
perror("grantpt");
exit(1);
}
if (unlockpt(master) < 0) {
perror("unlockpt");
exit(1);
}
}
void pty_resize(int w, int h)
{
struct winsize sz;
assert(master >= 0);
sz.ws_row = h;
sz.ws_col = w;
sz.ws_xpixel = sz.ws_ypixel = 0;
ioctl(master, TIOCSWINSZ, &sz);
}
int run_program_in_pty(const struct shell_data *shdata,
char *directory, char **program_args)
{
int slave, pid;
char *fallback_args[2];
assert(master >= 0);
ptyname[FILENAME_MAX-1] = '\0';
strncpy(ptyname, ptsname(master), FILENAME_MAX-1);
#if 0
{
struct winsize ws;
struct termios ts;
/*
* FIXME: think up some good defaults here
*/
if (!ioctl(0, TIOCGWINSZ, &ws))
ioctl(master, TIOCSWINSZ, &ws);
if (!tcgetattr(0, &ts))
tcsetattr(master, TCSANOW, &ts);
}
#endif
slave = open(ptyname, O_RDWR | O_NOCTTY);
if (slave < 0) {
perror("slave pty: open");
return 1;
}
/*
* Fork and execute the command.
*/
pid = fork();
if (pid < 0) {
perror("fork");
return 1;
}
if (pid == 0) {
int i, fd;
/*
* We are the child.
*/
close(master);
fcntl(slave, F_SETFD, 0); /* don't close on exec */
dup2(slave, 0);
dup2(slave, 1);
if (slave != 0 && slave != 1)
close(slave);
dup2(1, 2);
setsid();
setpgrp();
i = 0;
#ifdef TIOCNOTTY
if ((fd = open("/dev/tty", O_RDWR)) >= 0) {
ioctl(fd, TIOCNOTTY, &i);
close(fd);
}
#endif
/*
* Make the new pty our controlling terminal. On some OSes
* this is done with TIOCSCTTY; Cygwin doesn't have that, so
* instead it's done by simply opening the pty without
* O_NOCTTY. This code is primarily intended for Cygwin, but
* it's useful to have it work in other contexts for testing
* purposes, so I leave the TIOCSCTTY here anyway.
*/
if ((fd = open(ptyname, O_RDWR)) >= 0) {
#ifdef TIOCSCTTY
ioctl(fd, TIOCSCTTY, &i);
#endif
close(fd);
} else {
perror("slave pty: open");
exit(127);
}
tcsetpgrp(0, getpgrp());
for (i = 0; i < shdata->nenvvars; i++)
putenv(shdata->envvars[i]);
if (shdata->termtype)
putenv(shdata->termtype);
if (directory)
chdir(directory);
/*
* Use the provided shell program name, if the user gave
* one. Failing that, use $SHELL; failing that, look up
* the user's default shell in the password file; failing
* _that_, revert to the bog-standard /bin/sh.
*/
if (!program_args) {
char *shell;
shell = getenv("SHELL");
if (!shell) {
const char *login;
uid_t uid;
struct passwd *pwd;
/*
* For maximum generality in the face of multiple
* /etc/passwd entries with different login names and
* shells but a shared uid, we start by using
* getpwnam(getlogin()) if it's available - but we
* insist that its uid must match our real one, or we
* give up and fall back to getpwuid(getuid()).
*/
uid = getuid();
login = getlogin();
if (login && (pwd = getpwnam(login)) && pwd->pw_uid == uid)
shell = pwd->pw_shell;
else if ((pwd = getpwuid(uid)))
shell = pwd->pw_shell;
}
if (!shell)
shell = "/bin/sh";
fallback_args[0] = shell;
fallback_args[1] = NULL;
program_args = fallback_args;
}
execv(program_args[0], program_args);
/*
* If we're here, exec has gone badly foom.
*/
perror("exec");
exit(127);
}
close(slave);
return master;
}