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/*
* Copyright (C) 2011 by Nelson Elhage
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/select.h>
#include <sys/ioctl.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <stdarg.h>
#include <termios.h>
#include <signal.h>
#include "reptyr.h"
#include "reallocarray.h"
#include "platform/platform.h"
static int verbose = 0;
void _debug(const char *pfx, const char *msg, va_list ap) {
if (pfx)
fprintf(stderr, "%s", pfx);
vfprintf(stderr, msg, ap);
fprintf(stderr, "\n");
}
void die(const char *msg, ...) {
va_list ap;
va_start(ap, msg);
_debug("[!] ", msg, ap);
va_end(ap);
exit(1);
}
void debug(const char *msg, ...) {
va_list ap;
if (!verbose)
return;
va_start(ap, msg);
_debug("[+] ", msg, ap);
va_end(ap);
}
void error(const char *msg, ...) {
va_list ap;
va_start(ap, msg);
_debug("[-] ", msg, ap);
va_end(ap);
}
void setup_raw(struct termios *save) {
struct termios set;
if (tcgetattr(0, save) < 0) {
fprintf(stderr, "Unable to read terminal attributes: %m");
return;
}
set = *save;
cfmakeraw(&set);
if (tcsetattr(0, TCSANOW, &set) < 0)
die("Unable to set terminal attributes: %m");
}
void resize_pty(int pty) {
struct winsize sz;
if (ioctl(0, TIOCGWINSZ, &sz) < 0) {
// provide fake size to workaround some problems
struct winsize defaultsize = {30, 80, 640, 480};
if (ioctl(pty, TIOCSWINSZ, &defaultsize) < 0) {
fprintf(stderr, "Cannot set terminal size\n");
}
return;
}
ioctl(pty, TIOCSWINSZ, &sz);
}
int writeall(int fd, const void *buf, ssize_t count) {
ssize_t rv;
while (count > 0) {
rv = write(fd, buf, count);
if (rv < 0) {
if (errno == EINTR)
continue;
return rv;
}
count -= rv;
buf += rv;
}
return 0;
}
volatile sig_atomic_t winch_happened = 0;
void do_winch(int signal) {
winch_happened = 1;
}
void do_proxy(int pty) {
char buf[4096];
ssize_t count;
fd_set set;
struct timeval timeout;
while (1) {
if (winch_happened) {
winch_happened = 0;
/*
* FIXME: If a signal comes in after this point but before
* select(), the resize will be delayed until we get more
* input. signalfd() is probably the cleanest solution.
*/
resize_pty(pty);
}
FD_ZERO(&set);
FD_SET(0, &set);
FD_SET(pty, &set);
timeout.tv_sec = 0;
timeout.tv_usec = 1000;
if (select(pty + 1, &set, NULL, NULL, &timeout) < 0) {
if (errno == EINTR)
continue;
fprintf(stderr, "select: %m");
return;
}
if (FD_ISSET(0, &set)) {
count = read(0, buf, sizeof buf);
if (count < 0)
return;
writeall(pty, buf, count);
}
if (FD_ISSET(pty, &set)) {
count = read(pty, buf, sizeof buf);
if (count <= 0)
return;
writeall(1, buf, count);
}
}
}
void usage(char *me) {
fprintf(stderr, "Usage: %s [-s] PID\n", me);
fprintf(stderr, " %s -l|-L [COMMAND [ARGS]]\n", me);
fprintf(stderr, " -l Create a new pty pair and print the name of the slave.\n");
fprintf(stderr, " if there are command-line arguments after -l\n");
fprintf(stderr, " they are executed with REPTYR_PTY set to path of pty.\n");
fprintf(stderr, " -L Like '-l', but also redirect the child's stdio to the slave.\n");
fprintf(stderr, " -s Attach fds 0-2 on the target, even if it is not attached to a tty.\n");
fprintf(stderr, " -T Steal the entire terminal session of the target.\n");
fprintf(stderr, " [experimental] May be more reliable, and will attach all\n");
fprintf(stderr, " processes running on the terminal.\n");
fprintf(stderr, " -h Print this help message and exit.\n");
fprintf(stderr, " -v Print the version number and exit.\n");
fprintf(stderr, " -V Print verbose debug output.\n");
}
int main(int argc, char **argv) {
struct termios saved_termios;
struct sigaction act;
int pty;
int opt;
int err;
int do_attach = 1;
int force_stdio = 0;
int do_steal = 0;
int unattached_script_redirection = 0;
while ((opt = getopt(argc, argv, "hlLsTvV")) != -1) {
switch (opt) {
case 'h':
usage(argv[0]);
return 0;
case 'l':
do_attach = 0;
break;
case 'L':
do_attach = 0;
unattached_script_redirection = 1;
break;
case 's':
force_stdio = 1;
break;
case 'T':
do_steal = 1;
break;
case 'v':
printf("This is reptyr version %s.\n", REPTYR_VERSION);
printf(" by Nelson Elhage <nelhage@nelhage.com>\n");
printf("http://github.com/nelhage/reptyr/\n");
return 0;
case 'V':
verbose = 1;
break;
default:
usage(argv[0]);
return 1;
}
if (opt == 'l' || opt == 'L') break; // the rest is a command line
}
if (do_attach && optind >= argc) {
fprintf(stderr, "%s: No pid specified to attach\n", argv[0]);
usage(argv[0]);
return 1;
}
if (!do_steal) {
if ((pty = get_pt()) < 0)
die("Unable to allocate a new pseudo-terminal: %m");
if (unlockpt(pty) < 0)
die("Unable to unlockpt: %m");
if (grantpt(pty) < 0)
die("Unable to grantpt: %m");
}
if (do_attach) {
char *endptr = NULL;
errno = 0;
long t = strtol(argv[optind], &endptr, 10);
if (errno == ERANGE)
die("Invalid pid: %m");
if (*endptr)
die("Invalid pid: must be integer");
/* check for overflow/underflow */
pid_t child = (pid_t)t;
if (child < t || t < 1) /* pids can't be < 1, so no *real* underflow check */
die("Invalid pid: %s", strerror(ERANGE));
if (do_steal) {
err = steal_pty(child, &pty);
} else {
err = attach_child(child, ptsname(pty), force_stdio);
}
if (err) {
fprintf(stderr, "Unable to attach to pid %d: %s\n", child, strerror(err));
if (err == EPERM) {
check_ptrace_scope();
}
return 1;
}
} else {
printf("Opened a new pty: %s\n", ptsname(pty));
fflush(stdout);
if (argc > 2) {
if (!fork()) {
setenv("REPTYR_PTY", ptsname(pty), 1);
if (unattached_script_redirection) {
int f;
setpgid(0, getppid());
setsid();
f = open(ptsname(pty), O_RDONLY, 0);
dup2(f, 0);
close(f);
f = open(ptsname(pty), O_WRONLY, 0);
dup2(f, 1);
dup2(f, 2);
close(f);
}
close(pty);
execvp(argv[2], argv + 2);
exit(1);
}
}
}
setup_raw(&saved_termios);
memset(&act, 0, sizeof act);
act.sa_handler = do_winch;
act.sa_flags = 0;
sigaction(SIGWINCH, &act, NULL);
resize_pty(pty);
do_proxy(pty);
do {
errno = 0;
if (tcsetattr(0, TCSANOW, &saved_termios) && errno != EINTR)
die("Unable to tcsetattr: %m");
} while (errno == EINTR);
return 0;
}
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