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putty-source/unix/uxpty.c
Simon Tatham b4c8fd9d86 New abstraction 'Seat', to pass to backends. 
This is a new vtable-based abstraction which is passed to a backend in
place of Frontend, and it implements only the subset of the Frontend
functions needed by a backend. (Many other Frontend functions still
exist, notably the wide range of things called by terminal.c providing
platform-independent operations on the GUI terminal window.)

The purpose of making it a vtable is that this opens up the
possibility of creating a backend as an internal implementation detail
of some other activity, by providing just that one backend with a
custom Seat that implements the methods differently.

For example, this refactoring should make it feasible to directly
implement an SSH proxy type, aka the 'jump host' feature supported by
OpenSSH, aka 'open a secondary SSH session in MAINCHAN_DIRECT_TCP
mode, and then expose the main channel of that as the Socket for the
primary connection'. (Which of course you can already do by spawning
'plink -nc' as a separate proxy process, but this would permit it in
the _same_ process without anything getting confused.)

I've centralised a full set of stub methods in misc.c for the new
abstraction, which allows me to get rid of several annoying stubs in
the previous code. Also, while I'm here, I've moved a lot of
duplicated modalfatalbox() type functions from application main
program files into wincons.c / uxcons.c, which I think saves
duplication overall. (A minor visible effect is that the prefixes on
those console-based fatal error messages will now be more consistent
between applications.)
2018-10-11 19:58:42 +01:00

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/*
* Pseudo-tty backend for pterm.
*/
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <assert.h>
#include <fcntl.h>
#include <termios.h>
#include <grp.h>
#include <utmp.h>
#include <pwd.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/ioctl.h>
#include <errno.h>
#include "putty.h"
#include "tree234.h"
#ifndef OMIT_UTMP
#include <utmpx.h>
#endif
/* updwtmpx() needs the name of the wtmp file. Try to find it. */
#ifndef WTMPX_FILE
#ifdef _PATH_WTMPX
#define WTMPX_FILE _PATH_WTMPX
#else
#define WTMPX_FILE "/var/log/wtmpx"
#endif
#endif
#ifndef LASTLOG_FILE
#ifdef _PATH_LASTLOG
#define LASTLOG_FILE _PATH_LASTLOG
#else
#define LASTLOG_FILE "/var/log/lastlog"
#endif
#endif
/*
* Set up a default for vaguely sane systems. The idea is that if
* OMIT_UTMP is not defined, then at least one of the symbols which
* enable particular forms of utmp processing should be, if only so
* that a link error can warn you that you should have defined
* OMIT_UTMP if you didn't want any. Currently HAVE_PUTUTLINE is
* the only such symbol.
*/
#ifndef OMIT_UTMP
#if !defined HAVE_PUTUTLINE
#define HAVE_PUTUTLINE
#endif
#endif
typedef struct Pty Pty;
/*
* The pty_signal_pipe, along with the SIGCHLD handler, must be
* process-global rather than session-specific.
*/
static int pty_signal_pipe[2] = { -1, -1 }; /* obviously bogus initial val */
struct Pty {
Conf *conf;
int master_fd, slave_fd;
Seat *seat;
char name[FILENAME_MAX];
pid_t child_pid;
int term_width, term_height;
int child_dead, finished;
int exit_code;
bufchain output_data;
Backend backend;
};
/*
* We store our pty backends in a tree sorted by master fd, so that
* when we get an uxsel notification we know which backend instance
* is the owner of the pty that caused it.
*/
static int pty_compare_by_fd(void *av, void *bv)
{
Pty *a = (Pty *)av;
Pty *b = (Pty *)bv;
if (a->master_fd < b->master_fd)
return -1;
else if (a->master_fd > b->master_fd)
return +1;
return 0;
}
static int pty_find_by_fd(void *av, void *bv)
{
int a = *(int *)av;
Pty *b = (Pty *)bv;
if (a < b->master_fd)
return -1;
else if (a > b->master_fd)
return +1;
return 0;
}
static tree234 *ptys_by_fd = NULL;
/*
* We also have a tree sorted by child pid, so that when we wait()
* in response to the signal we know which backend instance is the
* owner of the process that caused the signal.
*/
static int pty_compare_by_pid(void *av, void *bv)
{
Pty *a = (Pty *)av;
Pty *b = (Pty *)bv;
if (a->child_pid < b->child_pid)
return -1;
else if (a->child_pid > b->child_pid)
return +1;
return 0;
}
static int pty_find_by_pid(void *av, void *bv)
{
pid_t a = *(pid_t *)av;
Pty *b = (Pty *)bv;
if (a < b->child_pid)
return -1;
else if (a > b->child_pid)
return +1;
return 0;
}
static tree234 *ptys_by_pid = NULL;
/*
* If we are using pty_pre_init(), it will need to have already
* allocated a pty structure, which we must then return from
* pty_init() rather than allocating a new one. Here we store that
* structure between allocation and use.
*
* Note that although most of this module is entirely capable of
* handling multiple ptys in a single process, pty_pre_init() is
* fundamentally _dependent_ on there being at most one pty per
* process, so the normal static-data constraints don't apply.
*
* Likewise, since utmp is only used via pty_pre_init, it too must
* be single-instance, so we can declare utmp-related variables
* here.
*/
static Pty *single_pty = NULL;
#ifndef OMIT_UTMP
static pid_t pty_utmp_helper_pid = -1;
static int pty_utmp_helper_pipe = -1;
static int pty_stamped_utmp;
static struct utmpx utmp_entry;
#endif
/*
* pty_argv is a grievous hack to allow a proper argv to be passed
* through from the Unix command line. Again, it doesn't really
* make sense outside a one-pty-per-process setup.
*/
char **pty_argv;
char *pty_osx_envrestore_prefix;
static void pty_close(Pty *pty);
static void pty_try_write(Pty *pty);
#ifndef OMIT_UTMP
static void setup_utmp(char *ttyname, char *location)
{
#ifdef HAVE_LASTLOG
struct lastlog lastlog_entry;
FILE *lastlog;
#endif
struct passwd *pw;
struct timeval tv;
pw = getpwuid(getuid());
memset(&utmp_entry, 0, sizeof(utmp_entry));
utmp_entry.ut_type = USER_PROCESS;
utmp_entry.ut_pid = getpid();
#if __GNUC__ >= 8
# pragma GCC diagnostic push
# pragma GCC diagnostic ignored "-Wstringop-truncation"
#endif // __GNUC__ >= 8
strncpy(utmp_entry.ut_line, ttyname+5, lenof(utmp_entry.ut_line));
strncpy(utmp_entry.ut_id, ttyname+8, lenof(utmp_entry.ut_id));
strncpy(utmp_entry.ut_user, pw->pw_name, lenof(utmp_entry.ut_user));
strncpy(utmp_entry.ut_host, location, lenof(utmp_entry.ut_host));
#if __GNUC__ >= 8
# pragma GCC diagnostic pop
#endif // __GNUC__ >= 8
/*
* Apparently there are some architectures where (struct
* utmpx).ut_tv is not essentially struct timeval (e.g. Linux
* amd64). Hence the temporary.
*/
gettimeofday(&tv, NULL);
utmp_entry.ut_tv.tv_sec = tv.tv_sec;
utmp_entry.ut_tv.tv_usec = tv.tv_usec;
setutxent();
pututxline(&utmp_entry);
endutxent();
updwtmpx(WTMPX_FILE, &utmp_entry);
#ifdef HAVE_LASTLOG
memset(&lastlog_entry, 0, sizeof(lastlog_entry));
strncpy(lastlog_entry.ll_line, ttyname+5, lenof(lastlog_entry.ll_line));
strncpy(lastlog_entry.ll_host, location, lenof(lastlog_entry.ll_host));
time(&lastlog_entry.ll_time);
if ((lastlog = fopen(LASTLOG_FILE, "r+")) != NULL) {
fseek(lastlog, sizeof(lastlog_entry) * getuid(), SEEK_SET);
fwrite(&lastlog_entry, 1, sizeof(lastlog_entry), lastlog);
fclose(lastlog);
}
#endif
pty_stamped_utmp = 1;
}
static void cleanup_utmp(void)
{
struct timeval tv;
if (!pty_stamped_utmp)
return;
utmp_entry.ut_type = DEAD_PROCESS;
memset(utmp_entry.ut_user, 0, lenof(utmp_entry.ut_user));
gettimeofday(&tv, NULL);
utmp_entry.ut_tv.tv_sec = tv.tv_sec;
utmp_entry.ut_tv.tv_usec = tv.tv_usec;
updwtmpx(WTMPX_FILE, &utmp_entry);
memset(utmp_entry.ut_line, 0, lenof(utmp_entry.ut_line));
utmp_entry.ut_tv.tv_sec = 0;
utmp_entry.ut_tv.tv_usec = 0;
setutxent();
pututxline(&utmp_entry);
endutxent();
pty_stamped_utmp = 0; /* ensure we never double-cleanup */
}
#endif
static void sigchld_handler(int signum)
{
if (write(pty_signal_pipe[1], "x", 1) <= 0)
/* not much we can do about it */;
}
static void pty_setup_sigchld_handler(void)
{
static int setup = FALSE;
if (!setup) {
putty_signal(SIGCHLD, sigchld_handler);
setup = TRUE;
}
}
#ifndef OMIT_UTMP
static void fatal_sig_handler(int signum)
{
putty_signal(signum, SIG_DFL);
cleanup_utmp();
raise(signum);
}
#endif
static int pty_open_slave(Pty *pty)
{
if (pty->slave_fd < 0) {
pty->slave_fd = open(pty->name, O_RDWR);
cloexec(pty->slave_fd);
}
return pty->slave_fd;
}
static void pty_open_master(Pty *pty)
{
#ifdef BSD_PTYS
const char chars1[] = "pqrstuvwxyz";
const char chars2[] = "0123456789abcdef";
const char *p1, *p2;
char master_name[20];
struct group *gp;
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) {
/*
* We must also check at this point that we are
* able to open the slave side of the pty. We
* wouldn't want to allocate the wrong master,
* get all the way down to forking, and _then_
* find we're unable to open the slave.
*/
strcpy(pty->name, master_name);
pty->name[5] = 't'; /* /dev/ptyXX -> /dev/ttyXX */
cloexec(pty->master_fd);
if (pty_open_slave(pty) >= 0 &&
access(pty->name, R_OK | W_OK) == 0)
goto got_one;
if (pty->slave_fd > 0)
close(pty->slave_fd);
pty->slave_fd = -1;
}
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:
/* We need to chown/chmod the /dev/ttyXX device. */
gp = getgrnam("tty");
chown(pty->name, getuid(), gp ? gp->gr_gid : -1);
chmod(pty->name, 0600);
#else
const int flags = O_RDWR
#ifdef O_NOCTTY
| O_NOCTTY
#endif
;
#ifdef HAVE_POSIX_OPENPT
#ifdef SET_NONBLOCK_VIA_OPENPT
/*
* OS X, as of 10.10 at least, doesn't permit me to set O_NONBLOCK
* on pty master fds via the usual fcntl mechanism. Fortunately,
* it does let me work around this by adding O_NONBLOCK to the
* posix_openpt flags parameter, which isn't a documented use of
* the API but seems to work. So we'll do that for now.
*/
pty->master_fd = posix_openpt(flags | O_NONBLOCK);
#else
pty->master_fd = posix_openpt(flags);
#endif
if (pty->master_fd < 0) {
perror("posix_openpt");
exit(1);
}
#else
pty->master_fd = open("/dev/ptmx", flags);
if (pty->master_fd < 0) {
perror("/dev/ptmx: open");
exit(1);
}
#endif
if (grantpt(pty->master_fd) < 0) {
perror("grantpt");
exit(1);
}
if (unlockpt(pty->master_fd) < 0) {
perror("unlockpt");
exit(1);
}
cloexec(pty->master_fd);
pty->name[FILENAME_MAX-1] = '\0';
strncpy(pty->name, ptsname(pty->master_fd), FILENAME_MAX-1);
#endif
#ifndef SET_NONBLOCK_VIA_OPENPT
nonblock(pty->master_fd);
#endif
if (!ptys_by_fd)
ptys_by_fd = newtree234(pty_compare_by_fd);
add234(ptys_by_fd, pty);
}
static Pty *new_pty_struct(void)
{
Pty *pty = snew(Pty);
pty->conf = NULL;
bufchain_init(&pty->output_data);
return pty;
}
/*
* Pre-initialisation. This is here to get around the fact that GTK
* doesn't like being run in setuid/setgid programs (probably
* sensibly). So before we initialise GTK - and therefore before we
* even process the command line - we check to see if we're running
* set[ug]id. If so, we open our pty master _now_, chown it as
* necessary, and drop privileges. We can always close it again
* later. If we're potentially going to be doing utmp as well, we
* also fork off a utmp helper process and communicate with it by
* means of a pipe; the utmp helper will keep privileges in order
* to clean up utmp when we exit (i.e. when its end of our pipe
* closes).
*/
void pty_pre_init(void)
{
#ifndef NO_PTY_PRE_INIT
Pty *pty;
#ifndef OMIT_UTMP
pid_t pid;
int pipefd[2];
#endif
pty = single_pty = new_pty_struct();
/* set the child signal handler straight away; it needs to be set
* before we ever fork. */
pty_setup_sigchld_handler();
pty->master_fd = pty->slave_fd = -1;
#ifndef OMIT_UTMP
pty_stamped_utmp = FALSE;
#endif
if (geteuid() != getuid() || getegid() != getgid()) {
pty_open_master(pty);
#ifndef OMIT_UTMP
/*
* Fork off the utmp helper.
*/
if (pipe(pipefd) < 0) {
perror("pterm: pipe");
exit(1);
}
cloexec(pipefd[0]);
cloexec(pipefd[1]);
pid = fork();
if (pid < 0) {
perror("pterm: fork");
exit(1);
} else if (pid == 0) {
char display[128], buffer[128];
int dlen, ret;
close(pipefd[1]);
/*
* Now sit here until we receive a display name from the
* other end of the pipe, and then stamp utmp. Unstamp utmp
* again, and exit, when the pipe closes.
*/
dlen = 0;
while (1) {
ret = read(pipefd[0], buffer, lenof(buffer));
if (ret <= 0) {
cleanup_utmp();
_exit(0);
} else if (!pty_stamped_utmp) {
if (dlen < lenof(display))
memcpy(display+dlen, buffer,
min(ret, lenof(display)-dlen));
if (buffer[ret-1] == '\0') {
/*
* Now we have a display name. NUL-terminate
* it, and stamp utmp.
*/
display[lenof(display)-1] = '\0';
/*
* Trap as many fatal signals as we can in the
* hope of having the best possible chance to
* clean up utmp before termination. We are
* unfortunately unprotected against SIGKILL,
* but that's life.
*/
putty_signal(SIGHUP, fatal_sig_handler);
putty_signal(SIGINT, fatal_sig_handler);
putty_signal(SIGQUIT, fatal_sig_handler);
putty_signal(SIGILL, fatal_sig_handler);
putty_signal(SIGABRT, fatal_sig_handler);
putty_signal(SIGFPE, fatal_sig_handler);
putty_signal(SIGPIPE, fatal_sig_handler);
putty_signal(SIGALRM, fatal_sig_handler);
putty_signal(SIGTERM, fatal_sig_handler);
putty_signal(SIGSEGV, fatal_sig_handler);
putty_signal(SIGUSR1, fatal_sig_handler);
putty_signal(SIGUSR2, fatal_sig_handler);
#ifdef SIGBUS
putty_signal(SIGBUS, fatal_sig_handler);
#endif
#ifdef SIGPOLL
putty_signal(SIGPOLL, fatal_sig_handler);
#endif
#ifdef SIGPROF
putty_signal(SIGPROF, fatal_sig_handler);
#endif
#ifdef SIGSYS
putty_signal(SIGSYS, fatal_sig_handler);
#endif
#ifdef SIGTRAP
putty_signal(SIGTRAP, fatal_sig_handler);
#endif
#ifdef SIGVTALRM
putty_signal(SIGVTALRM, fatal_sig_handler);
#endif
#ifdef SIGXCPU
putty_signal(SIGXCPU, fatal_sig_handler);
#endif
#ifdef SIGXFSZ
putty_signal(SIGXFSZ, fatal_sig_handler);
#endif
#ifdef SIGIO
putty_signal(SIGIO, fatal_sig_handler);
#endif
setup_utmp(pty->name, display);
}
}
}
} else {
close(pipefd[0]);
pty_utmp_helper_pid = pid;
pty_utmp_helper_pipe = pipefd[1];
}
#endif
}
/* Drop privs. */
{
#ifndef HAVE_NO_SETRESUID
int gid = getgid(), uid = getuid();
int setresgid(gid_t, gid_t, gid_t);
int setresuid(uid_t, uid_t, uid_t);
if (setresgid(gid, gid, gid) < 0) {
perror("setresgid");
exit(1);
}
if (setresuid(uid, uid, uid) < 0) {
perror("setresuid");
exit(1);
}
#else
if (setgid(getgid()) < 0) {
perror("setgid");
exit(1);
}
if (setuid(getuid()) < 0) {
perror("setuid");
exit(1);
}
#endif
}
#endif /* NO_PTY_PRE_INIT */
}
void pty_real_select_result(Pty *pty, int event, int status)
{
char buf[4096];
int ret;
int finished = FALSE;
if (event < 0) {
/*
* We've been called because our child process did
* something. `status' tells us what.
*/
if ((WIFEXITED(status) || WIFSIGNALED(status))) {
/*
* The primary child process died. We could keep
* the terminal open for remaining subprocesses to
* output to, but conventional wisdom seems to feel
* that that's the Wrong Thing for an xterm-alike,
* so we bail out now (though we don't necessarily
* _close_ the window, depending on the state of
* Close On Exit). This would be easy enough to
* change or make configurable if necessary.
*/
pty->exit_code = status;
pty->child_dead = TRUE;
del234(ptys_by_pid, pty);
finished = TRUE;
}
} else {
if (event == 1) {
ret = read(pty->master_fd, buf, sizeof(buf));
/*
* Clean termination condition is that either ret == 0, or ret
* < 0 and errno == EIO. Not sure why the latter, but it seems
* to happen. Boo.
*/
if (ret == 0 || (ret < 0 && errno == EIO)) {
/*
* We assume a clean exit if the pty has closed but the
* actual child process hasn't. The only way I can
* imagine this happening is if it detaches itself from
* the pty and goes daemonic - in which case the
* expected usage model would precisely _not_ be for
* the pterm window to hang around!
*/
finished = TRUE;
if (!pty->child_dead)
pty->exit_code = 0;
} else if (ret < 0) {
perror("read pty master");
exit(1);
} else if (ret > 0) {
seat_stdout(pty->seat, buf, ret);
}
} else if (event == 2) {
/*
* Attempt to send data down the pty.
*/
pty_try_write(pty);
}
}
if (finished && !pty->finished) {
int close_on_exit;
uxsel_del(pty->master_fd);
pty_close(pty);
pty->master_fd = -1;
pty->finished = TRUE;
/*
* This is a slight layering-violation sort of hack: only
* if we're not closing on exit (COE is set to Never, or to
* Only On Clean and it wasn't a clean exit) do we output a
* `terminated' message.
*/
close_on_exit = conf_get_int(pty->conf, CONF_close_on_exit);
if (close_on_exit == FORCE_OFF ||
(close_on_exit == AUTO && pty->exit_code != 0)) {
char message[512];
message[0] = '\0';
if (WIFEXITED(pty->exit_code))
sprintf(message, "\r\n[pterm: process terminated with exit"
" code %d]\r\n", WEXITSTATUS(pty->exit_code));
else if (WIFSIGNALED(pty->exit_code))
#ifdef HAVE_NO_STRSIGNAL
sprintf(message, "\r\n[pterm: process terminated on signal"
" %d]\r\n", WTERMSIG(pty->exit_code));
#else
sprintf(message, "\r\n[pterm: process terminated on signal"
" %d (%.400s)]\r\n", WTERMSIG(pty->exit_code),
strsignal(WTERMSIG(pty->exit_code)));
#endif
seat_stdout(pty->seat, message, strlen(message));
}
seat_notify_remote_exit(pty->seat);
}
}
void pty_select_result(int fd, int event)
{
Pty *pty;
if (fd == pty_signal_pipe[0]) {
pid_t pid;
int status;
char c[1];
if (read(pty_signal_pipe[0], c, 1) <= 0)
/* ignore error */;
/* ignore its value; it'll be `x' */
do {
pid = waitpid(-1, &status, WNOHANG);
pty = find234(ptys_by_pid, &pid, pty_find_by_pid);
if (pty)
pty_real_select_result(pty, -1, status);
} while (pid > 0);
} else {
pty = find234(ptys_by_fd, &fd, pty_find_by_fd);
if (pty)
pty_real_select_result(pty, event, 0);
}
}
static void pty_uxsel_setup(Pty *pty)
{
int rwx;
rwx = 1; /* always want to read from pty */
if (bufchain_size(&pty->output_data))
rwx |= 2; /* might also want to write to it */
uxsel_set(pty->master_fd, rwx, pty_select_result);
/*
* In principle this only needs calling once for all pty
* backend instances, but it's simplest just to call it every
* time; uxsel won't mind.
*/
uxsel_set(pty_signal_pipe[0], 1, pty_select_result);
}
/*
* 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 const char *pty_init(Seat *seat, Backend **backend_handle,
LogContext *logctx, Conf *conf,
const char *host, int port,
char **realhost, int nodelay, int keepalive)
{
int slavefd;
pid_t pid, pgrp;
#ifndef NOT_X_WINDOWS /* for Mac OS X native compilation */
int got_windowid;
long windowid;
#endif
Pty *pty;
if (single_pty) {
pty = single_pty;
assert(pty->conf == NULL);
} else {
pty = new_pty_struct();
pty->master_fd = pty->slave_fd = -1;
#ifndef OMIT_UTMP
pty_stamped_utmp = FALSE;
#endif
}
pty->seat = seat;
pty->backend.vt = &pty_backend;
*backend_handle = &pty->backend;
pty->conf = conf_copy(conf);
pty->term_width = conf_get_int(conf, CONF_width);
pty->term_height = conf_get_int(conf, CONF_height);
if (pty->master_fd < 0)
pty_open_master(pty);
#ifndef OMIT_UTMP
/*
* Stamp utmp (that is, tell the utmp helper process to do so),
* or not.
*/
if (pty_utmp_helper_pipe >= 0) { /* if it's < 0, we can't anyway */
if (!conf_get_int(conf, CONF_stamp_utmp)) {
close(pty_utmp_helper_pipe); /* just let the child process die */
pty_utmp_helper_pipe = -1;
} else {
const char *location = seat_get_x_display(pty->seat);
int len = strlen(location)+1, pos = 0; /* +1 to include NUL */
while (pos < len) {
int ret = write(pty_utmp_helper_pipe, location+pos, len - pos);
if (ret < 0) {
perror("pterm: writing to utmp helper process");
close(pty_utmp_helper_pipe); /* arrgh, just give up */
pty_utmp_helper_pipe = -1;
break;
}
pos += ret;
}
}
}
#endif
#ifndef NOT_X_WINDOWS /* for Mac OS X native compilation */
got_windowid = seat_get_windowid(pty->seat, &windowid);
#endif
/*
* Set up the signal handler to catch SIGCHLD, if pty_pre_init
* didn't already do it.
*/
pty_setup_sigchld_handler();
/*
* Fork and execute the command.
*/
pid = fork();
if (pid < 0) {
perror("fork");
exit(1);
}
if (pid == 0) {
struct termios attrs;
/*
* We are the child.
*/
if (pty_osx_envrestore_prefix) {
int plen = strlen(pty_osx_envrestore_prefix);
extern char **environ;
char **ep;
restart_osx_env_restore:
for (ep = environ; *ep; ep++) {
char *e = *ep;
if (!strncmp(e, pty_osx_envrestore_prefix, plen)) {
int unset = (e[plen] == 'u');
char *pname = dupprintf("%.*s", (int)strcspn(e, "="), e);
char *name = pname + plen + 1;
char *value = e + strcspn(e, "=");
if (*value) value++;
value = dupstr(value);
if (unset)
unsetenv(name);
else
setenv(name, value, 1);
unsetenv(pname);
sfree(pname);
sfree(value);
goto restart_osx_env_restore;
}
}
}
slavefd = pty_open_slave(pty);
if (slavefd < 0) {
perror("slave pty: open");
_exit(1);
}
close(pty->master_fd);
noncloexec(slavefd);
dup2(slavefd, 0);
dup2(slavefd, 1);
dup2(slavefd, 2);
close(slavefd);
setsid();
#ifdef TIOCSCTTY
ioctl(0, TIOCSCTTY, 1);
#endif
pgrp = getpid();
tcsetpgrp(0, pgrp);
/*
* Set up configuration-dependent termios settings on the new
* pty. Linux would have let us do this on the pty master
* before we forked, but that fails on OS X, so we do it here
* instead.
*/
if (tcgetattr(0, &attrs) == 0) {
/*
* Set the backspace character to be whichever of ^H and
* ^? is specified by bksp_is_delete.
*/
attrs.c_cc[VERASE] = conf_get_int(conf, CONF_bksp_is_delete)
? '\177' : '\010';
/*
* Set the IUTF8 bit iff the character set is UTF-8.
*/
#ifdef IUTF8
if (seat_is_utf8(seat))
attrs.c_iflag |= IUTF8;
else
attrs.c_iflag &= ~IUTF8;
#endif
tcsetattr(0, TCSANOW, &attrs);
}
setpgid(pgrp, pgrp);
{
int ptyfd = open(pty->name, O_WRONLY, 0);
if (ptyfd >= 0)
close(ptyfd);
}
setpgid(pgrp, pgrp);
{
char *term_env_var = dupprintf("TERM=%s",
conf_get_str(conf, CONF_termtype));
putenv(term_env_var);
/* We mustn't free term_env_var, as putenv links it into the
* environment in place.
*/
}
#ifndef NOT_X_WINDOWS /* for Mac OS X native compilation */
if (got_windowid) {
char *windowid_env_var = dupprintf("WINDOWID=%ld", windowid);
putenv(windowid_env_var);
/* We mustn't free windowid_env_var, as putenv links it into the
* environment in place.
*/
}
{
/*
* In case we were invoked with a --display argument that
* doesn't match DISPLAY in our actual environment, we
* should set DISPLAY for processes running inside the
* terminal to match the display the terminal itself is
* on.
*/
const char *x_display = seat_get_x_display(pty->seat);
char *x_display_env_var = dupprintf("DISPLAY=%s", x_display);
putenv(x_display_env_var);
/* As above, we don't free this. */
}
#endif
{
char *key, *val;
for (val = conf_get_str_strs(conf, CONF_environmt, NULL, &key);
val != NULL;
val = conf_get_str_strs(conf, CONF_environmt, key, &key)) {
char *varval = dupcat(key, "=", val, NULL);
putenv(varval);
/*
* We must not free varval, since putenv links it
* into the environment _in place_. Weird, but
* there we go. Memory usage will be rationalised
* as soon as we exec anyway.
*/
}
}
/*
* SIGINT, SIGQUIT and SIGPIPE may have been set to ignored by
* our parent, particularly by things like sh -c 'pterm &' and
* some window or session managers. SIGPIPE was also
* (potentially) blocked by us during startup. Reverse all
* this for our child process.
*/
putty_signal(SIGINT, SIG_DFL);
putty_signal(SIGQUIT, SIG_DFL);
putty_signal(SIGPIPE, SIG_DFL);
block_signal(SIGPIPE, 0);
if (pty_argv) {
/*
* Exec the exact argument list we were given.
*/
execvp(pty_argv[0], pty_argv);
/*
* If that fails, and if we had exactly one argument, pass
* that argument to $SHELL -c.
*
* This arranges that we can _either_ follow 'pterm -e'
* with a list of argv elements to be fed directly to
* exec, _or_ with a single argument containing a command
* to be parsed by a shell (but, in cases of doubt, the
* former is more reliable).
*
* A quick survey of other terminal emulators' -e options
* (as of Debian squeeze) suggests that:
*
* - xterm supports both modes, more or less like this
* - gnome-terminal will only accept a one-string shell command
* - Eterm, kterm and rxvt will only accept a list of
* argv elements (as did older versions of pterm).
*
* It therefore seems important to support both usage
* modes in order to be a drop-in replacement for either
* xterm or gnome-terminal, and hence for anyone's
* plausible uses of the Debian-style alias
* 'x-terminal-emulator'...
*/
if (pty_argv[1] == NULL) {
char *shell = getenv("SHELL");
if (shell)
execl(shell, shell, "-c", pty_argv[0], (void *)NULL);
}
} else {
char *shell = getenv("SHELL");
char *shellname;
if (conf_get_int(conf, CONF_login_shell)) {
char *p = strrchr(shell, '/');
shellname = snewn(2+strlen(shell), char);
p = p ? p+1 : shell;
sprintf(shellname, "-%s", p);
} else
shellname = shell;
execl(getenv("SHELL"), shellname, (void *)NULL);
}
/*
* If we're here, exec has gone badly foom.
*/
perror("exec");
_exit(127);
} else {
pty->child_pid = pid;
pty->child_dead = FALSE;
pty->finished = FALSE;
if (pty->slave_fd > 0)
close(pty->slave_fd);
if (!ptys_by_pid)
ptys_by_pid = newtree234(pty_compare_by_pid);
add234(ptys_by_pid, pty);
}
if (pty_signal_pipe[0] < 0) {
if (pipe(pty_signal_pipe) < 0) {
perror("pipe");
exit(1);
}
cloexec(pty_signal_pipe[0]);
cloexec(pty_signal_pipe[1]);
}
pty_uxsel_setup(pty);
*realhost = dupstr("");
return NULL;
}
static void pty_reconfig(Backend *be, Conf *conf)
{
Pty *pty = container_of(be, Pty, backend);
/*
* We don't have much need to reconfigure this backend, but
* unfortunately we do need to pick up the setting of Close On
* Exit so we know whether to give a `terminated' message.
*/
conf_copy_into(pty->conf, conf);
}
/*
* Stub routine (never called in pterm).
*/
static void pty_free(Backend *be)
{
Pty *pty = container_of(be, Pty, backend);
/* Either of these may fail `not found'. That's fine with us. */
del234(ptys_by_pid, pty);
del234(ptys_by_fd, pty);
bufchain_clear(&pty->output_data);
conf_free(pty->conf);
pty->conf = NULL;
if (pty == single_pty) {
/*
* Leave this structure around in case we need to Restart
* Session.
*/
} else {
sfree(pty);
}
}
static void pty_try_write(Pty *pty)
{
void *data;
int len, ret;
assert(pty->master_fd >= 0);
while (bufchain_size(&pty->output_data) > 0) {
bufchain_prefix(&pty->output_data, &data, &len);
ret = write(pty->master_fd, data, len);
if (ret < 0 && (errno == EWOULDBLOCK)) {
/*
* We've sent all we can for the moment.
*/
break;
}
if (ret < 0) {
perror("write pty master");
exit(1);
}
bufchain_consume(&pty->output_data, ret);
}
pty_uxsel_setup(pty);
}
/*
* Called to send data down the pty.
*/
static int pty_send(Backend *be, const char *buf, int len)
{
Pty *pty = container_of(be, Pty, backend);
if (pty->master_fd < 0)
return 0; /* ignore all writes if fd closed */
bufchain_add(&pty->output_data, buf, len);
pty_try_write(pty);
return bufchain_size(&pty->output_data);
}
static void pty_close(Pty *pty)
{
if (pty->master_fd >= 0) {
close(pty->master_fd);
pty->master_fd = -1;
}
#ifndef OMIT_UTMP
if (pty_utmp_helper_pipe >= 0) {
close(pty_utmp_helper_pipe); /* this causes utmp to be cleaned up */
pty_utmp_helper_pipe = -1;
}
#endif
}
/*
* Called to query the current socket sendability status.
*/
static int pty_sendbuffer(Backend *be)
{
/* Pty *pty = container_of(be, Pty, backend); */
return 0;
}
/*
* Called to set the size of the window
*/
static void pty_size(Backend *be, int width, int height)
{
Pty *pty = container_of(be, Pty, backend);
struct winsize size;
int xpixel = 0, ypixel = 0;
pty->term_width = width;
pty->term_height = height;
seat_get_char_cell_size(pty->seat, &xpixel, &ypixel);
size.ws_row = (unsigned short)pty->term_height;
size.ws_col = (unsigned short)pty->term_width;
size.ws_xpixel = (unsigned short)pty->term_width * xpixel;
size.ws_ypixel = (unsigned short)pty->term_height * ypixel;
ioctl(pty->master_fd, TIOCSWINSZ, (void *)&size);
return;
}
/*
* Send special codes.
*/
static void pty_special(Backend *be, SessionSpecialCode code, int arg)
{
/* Pty *pty = container_of(be, Pty, backend); */
/* Do nothing! */
return;
}
/*
* Return a list of the special codes that make sense in this
* protocol.
*/
static const SessionSpecial *pty_get_specials(Backend *be)
{
/* Pty *pty = container_of(be, Pty, backend); */
/*
* Hmm. When I get round to having this actually usable, it
* might be quite nice to have the ability to deliver a few
* well chosen signals to the child process - SIGINT, SIGTERM,
* SIGKILL at least.
*/
return NULL;
}
static int pty_connected(Backend *be)
{
/* Pty *pty = container_of(be, Pty, backend); */
return TRUE;
}
static int pty_sendok(Backend *be)
{
/* Pty *pty = container_of(be, Pty, backend); */
return 1;
}
static void pty_unthrottle(Backend *be, int backlog)
{
/* Pty *pty = container_of(be, Pty, backend); */
/* do nothing */
}
static int pty_ldisc(Backend *be, int option)
{
/* Pty *pty = container_of(be, Pty, backend); */
return 0; /* neither editing nor echoing */
}
static void pty_provide_ldisc(Backend *be, Ldisc *ldisc)
{
/* Pty *pty = container_of(be, Pty, backend); */
/* This is a stub. */
}
static int pty_exitcode(Backend *be)
{
Pty *pty = container_of(be, Pty, backend);
if (!pty->finished)
return -1; /* not dead yet */
else
return pty->exit_code;
}
static int pty_cfg_info(Backend *be)
{
/* Pty *pty = container_of(be, Pty, backend); */
return 0;
}
const struct BackendVtable pty_backend = {
pty_init,
pty_free,
pty_reconfig,
pty_send,
pty_sendbuffer,
pty_size,
pty_special,
pty_get_specials,
pty_connected,
pty_exitcode,
pty_sendok,
pty_ldisc,
pty_provide_ldisc,
pty_unthrottle,
pty_cfg_info,
NULL /* test_for_upstream */,
"pty",
-1,
0
};
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