rlgwebd/ptyhelper.c
2012-05-06 08:45:40 -07:00

149 lines
3.5 KiB
C

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <pty.h>
#include <utmp.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/select.h>
#include <termios.h>
int got_sighup = 0;
void handle_HUP(int signum) {
if (signum == SIGHUP)
got_sighup = 1;
return;
}
int main(int argc, char *argv[]) {
int ptymaster, ptyslave; /* File descriptors */
int child;
int status, selstatus;
int w = 80, h = 24, t;
struct sigaction sighup_act;
fd_set readset;
struct timeval select_time;
char buf[4096];
int nread;
char *penv, *ptmp;
#if 0
struct termios ptysettings;
#endif
struct winsize ptysize;
if (argc == 1) {
fprintf(stderr, "No command given.\n");
exit(1);
}
/* Set up the signal handler. */
sighup_act.sa_handler = &handle_HUP;
sighup_act.sa_flags = SA_RESTART;
sigaction(SIGHUP, &sighup_act, NULL);
/* Check the environment for configuration options. */
penv = getenv("PTYHELPER");
if (penv != NULL) {
t = strtol(penv, &ptmp, 10);
if (t > 0 && t < 256)
h = t;
if (*ptmp != '\0') {
penv = ptmp + 1;
t = strtol(penv, &ptmp, 10);
if (t > 0 && t < 256)
w = t;
}
}
/* Set up the size. */
ptysize.ws_row = h;
ptysize.ws_col = w;
/* Open a pty */
if (openpty(&ptymaster, &ptyslave, NULL, NULL, &ptysize)) {
return 1;
}
#if 0
/* Put it into raw mode. */
tcgetattr(ptyslave, &ptysettings);
cfmakeraw(&ptysettings);
tcsetattr(ptyslave, TCSANOW, &ptysettings);
#endif
/* Start the child */
/* forkpty() might be more convenient. */
if (!(child = fork())) {
/* Child process */
login_tty(ptyslave);
close(ptymaster);
execvp(argv[1], argv + 1);
perror("execvp() failed");
return 1;
}
close(ptyslave);
while (1) {
/* Now do a select() over stdin and ptymaster, and write anything that
* appears to ptymaster and stdout respectively. */
FD_ZERO(&readset);
FD_SET(0, &readset);
FD_SET(ptymaster, &readset);
select_time.tv_sec = 1;
select_time.tv_usec = 0;
selstatus = select(ptymaster + 1, &readset, NULL, NULL, &select_time);
if (selstatus > 0) {
/* TODO make sure it all gets written if a signal interrupts write(). */
if (FD_ISSET(0, &readset)) {
nread = read(0, buf, 4096);
if (nread > 0) {
write(ptymaster, buf, nread);
}
}
if (FD_ISSET(ptymaster, &readset)) {
nread = read(ptymaster, buf, 4096);
if (nread > 0) {
write(1, buf, nread);
}
}
}
/* Periodically check to see if we're done. */
/* TODO: catch SIGCHLD and only wait() if it is delivered. */
if (waitpid(child, &status, WNOHANG)) {
break;
}
/* If node sighup's us, pass it along. */
if (got_sighup) {
kill(child, SIGHUP);
}
}
/* Get any leftover output and clean up. */
/* FIXME looping over select() is pointless if there's only one fd that
* nothing's writing to. Just loop over read() until it's empty. */
while (1) {
FD_ZERO(&readset);
FD_SET(ptymaster, &readset);
select_time.tv_sec = 0;
select_time.tv_usec = 0;
if (select(ptymaster + 1, &readset, NULL, NULL, &select_time) > 0) {
nread = read(ptymaster, buf, 4096);
if (nread > 0) {
write(1, buf, nread);
}
else
break;
}
else
break;
}
close(ptymaster);
/* Return the child's exit status. */
if (WIFEXITED(status))
return WEXITSTATUS(status);
return 0;
}