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Add support for session switching #27

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130 changes: 114 additions & 16 deletions attach.c
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Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,26 @@
static struct termios cur_term;
/* 1 if the window size changed */
static int win_changed;
/* Switch support: press DTACH_SWITCH_KEY to run DTACH_SWITCH_CMD which prints
** a socket path (first line) to switch to. */
static char switch_key;
static char *switch_cmd;

static void
enter_raw_mode(void)
{
cur_term = orig_term;
cur_term.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP|INLCR|IGNCR|ICRNL);
cur_term.c_iflag &= ~(IXON|IXOFF);
cur_term.c_oflag &= ~(OPOST);
cur_term.c_lflag &= ~(ECHO|ECHONL|ICANON|ISIG|IEXTEN);
cur_term.c_cflag &= ~(CSIZE|PARENB);
cur_term.c_cflag |= CS8;
cur_term.c_cc[VLNEXT] = VDISABLE;
cur_term.c_cc[VMIN] = 1;
cur_term.c_cc[VTIME] = 0;
tcsetattr(0, TCSADRAIN, &cur_term);
}

/* Restores the original terminal settings. */
static void
Expand Down Expand Up @@ -104,14 +124,93 @@ win_change(ATTRIBUTE_UNUSED int sig)

/* Handles input from the keyboard. */
static void
process_kbd(int s, struct packet *pkt)
process_kbd(int *ps, struct packet *pkt)
{
/* Switch key: run external selector command to choose new socket. */
if (switch_key && switch_cmd && pkt->u.buf[0] == (unsigned char)switch_key)
{
char line[512];
char *nl;
int do_switch = 0;

/* Tell current master we are detaching while selecting. */
pkt->type = MSG_DETACH;
write_packet_or_fail(*ps, pkt);

/* Restore original terminal settings before running external command. */
// tcsetattr(0, TCSADRAIN, &orig_term);
// fflush(stdout);
restore_term();

FILE *fp = popen(switch_cmd, "r");
if (fp)
{
if (fgets(line, sizeof(line), fp))
{
nl = strpbrk(line, "\r\n");
if (nl) *nl = '\0';
/* Trim trailing spaces */
for (nl = line + strlen(line);
nl > line && nl[-1] == ' '; --nl)
nl[-1] = '\0';
if (line[0] && strcmp(line, sockname) != 0)
do_switch = 1;
}
pclose(fp);
}

/* Re-enter raw mode. */
enter_raw_mode();

if (do_switch)
{
int newfd = connect_socket(line);
if (newfd >= 0)
{
close(*ps);
*ps = newfd;
sockname = strdup(line); /* update global */

/* Clear screen */
write_buf_or_fail(1, "\33[H\33[J", 6);

/* Attach handshake */
memset(pkt, 0, sizeof(*pkt));
pkt->type = MSG_ATTACH;
write_packet_or_fail(*ps, pkt);
pkt->type = MSG_REDRAW;
pkt->len = redraw_method;
ioctl(0, TIOCGWINSZ, &pkt->u.ws);
write_packet_or_fail(*ps, pkt);

printf(EOS "\r\n[switched to %s]\r\n", line);
fflush(stdout);
return;
}
else
{
printf(EOS "\r\n[switch failed: %s]\r\n",
strerror(errno));
}
}

/* Reattach original session (or failed switch). */
memset(pkt, 0, sizeof(*pkt));
pkt->type = MSG_ATTACH;
write_packet_or_fail(*ps, pkt);
pkt->type = MSG_REDRAW;
pkt->len = redraw_method;
ioctl(0, TIOCGWINSZ, &pkt->u.ws);
write_packet_or_fail(*ps, pkt);
return;
}

/* Suspend? */
if (!no_suspend && (pkt->u.buf[0] == cur_term.c_cc[VSUSP]))
{
/* Tell the master that we are suspending. */
pkt->type = MSG_DETACH;
write_packet_or_fail(s, pkt);
write_packet_or_fail(*ps, pkt);

/* And suspend... */
tcsetattr(0, TCSADRAIN, &orig_term);
Expand All @@ -121,13 +220,13 @@ process_kbd(int s, struct packet *pkt)

/* Tell the master that we are returning. */
pkt->type = MSG_ATTACH;
write_packet_or_fail(s, pkt);
write_packet_or_fail(*ps, pkt);

/* We would like a redraw, too. */
pkt->type = MSG_REDRAW;
pkt->len = redraw_method;
ioctl(0, TIOCGWINSZ, &pkt->u.ws);
write_packet_or_fail(s, pkt);
write_packet_or_fail(*ps, pkt);
return;
}
/* Detach char? */
Expand All @@ -141,7 +240,7 @@ process_kbd(int s, struct packet *pkt)
win_changed = 1;

/* Push it out */
write_packet_or_fail(s, pkt);
write_packet_or_fail(*ps, pkt);
}

int
Expand Down Expand Up @@ -189,6 +288,14 @@ attach_main(int noerror)
return 1;
}

/* Read switch env vars (optional) */
{
char *k = getenv("DTACH_SWITCH_KEY");
char *c = getenv("DTACH_SWITCH_CMD");
if (k && k[0]) switch_key = k[0];
if (c && *c) switch_cmd = c;
}

/* The current terminal settings are equal to the original terminal
** settings at this point. */
cur_term = orig_term;
Expand All @@ -206,16 +313,7 @@ attach_main(int noerror)
signal(SIGWINCH, win_change);

/* Set raw mode. */
cur_term.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP|INLCR|IGNCR|ICRNL);
cur_term.c_iflag &= ~(IXON|IXOFF);
cur_term.c_oflag &= ~(OPOST);
cur_term.c_lflag &= ~(ECHO|ECHONL|ICANON|ISIG|IEXTEN);
cur_term.c_cflag &= ~(CSIZE|PARENB);
cur_term.c_cflag |= CS8;
cur_term.c_cc[VLNEXT] = VDISABLE;
cur_term.c_cc[VMIN] = 1;
cur_term.c_cc[VTIME] = 0;
tcsetattr(0, TCSADRAIN, &cur_term);
enter_raw_mode();

/* Clear the screen. This assumes VT100. */
write_buf_or_fail(1, "\33[H\33[J", 6);
Expand Down Expand Up @@ -279,7 +377,7 @@ attach_main(int noerror)
exit(1);

pkt.len = len;
process_kbd(s, &pkt);
process_kbd(&s, &pkt);
n--;
}

Expand Down