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#include "config.h"
extern FILE *log_fp;
int copy_a_bit(int in_fd, int out_fd, int dribble_fd,char *message) ;
void connect_direct(char * path) ;
void connect_ssh(char *host, char *path) ;
#define UNIX_PATH_MAX 108
/*
$0 /tmp/my-socket
or
$0 user@hostname:/tmp/my-socket
In the latter case, we open an ssh connection to user@hostname then
run $0 on the remote machine with the remainder of the command
*/
int was_interrupted=0, time_to_die=0;
void control_c_pressed(int signal) {
was_interrupted=1;
}
void tears_in_the_rain(int signal) {
fprintf(log_fp, "Got signal %d, closing down\n", signal);
time_to_die=signal;
}
main(int argc,char *argv[], char *envp[]) {
char *host=NULL; /* "hostname" or "user@hostname" */
char *path; /* path to socket */
char *p;
struct sigaction act;
if(argc!=2) {
fprintf(stderr, "%s: unrecognized arguments\nusage: %s /path/to/socket\n %s remote_user@remote_host:/path/to/socket\n", argv[0], argv[0], argv[0]);
exit(1);
}
p=strdup(argv[1]);
log_fp=stderr;
if(path=strchr(p,':')) {
host=p;
*path='\0';
path++;
} else {
path=p;
}
/* catch SIGINT and send character \003 over the link */
act.sa_handler=control_c_pressed;
sigemptyset(&(act.sa_mask));
act.sa_flags=0;
sigaction(SIGINT,&act,0);
/* catch SIGCHLD and exit */
act.sa_handler=tears_in_the_rain;
sigemptyset(&(act.sa_mask));
act.sa_flags=SA_RESETHAND;
sigaction(SIGCHLD,&act,0);
sigaction(SIGQUIT,&act,0);
if(host) {
logprintf("attachtty","connecting through ssh to %s on %s\n",path,host);
connect_ssh(host,path);
} else {
logprintf("attachtty","connecting directly to %s\n",path);
connect_direct(path);
}
}
/* copy between stdin,stdout and unix-domain socket */
void connect_direct(char * path) {
int sock=-1;
struct pollfd ufds[3];
struct sockaddr_un s_a;
s_a.sun_family=AF_UNIX;
strncpy(s_a.sun_path,path,UNIX_PATH_MAX);
s_a.sun_path[UNIX_PATH_MAX-1]='\0';
sock=socket(PF_UNIX,SOCK_STREAM,0);
if(sock==-1) bail("attachtty","socket");
if(connect(sock,(const struct sockaddr *) &s_a,sizeof s_a)!=0)
bail("attachtty","connect");
while(! time_to_die) {
if(was_interrupted) {
write(sock,"\003",1);
was_interrupted=0;
}
ufds[0].fd=sock; ufds[0].events=POLLIN;
ufds[1].fd=0; ufds[1].events=POLLIN|POLLHUP;
if (poll(ufds,2 ,-1) == -1) continue;
if(ufds[0].revents & POLLIN)
copy_a_bit(sock,1,-1,"copying from socket");
if(ufds[1].revents & POLLIN) {
int n=copy_a_bit(0,sock,-1,"copying to socket");
if(n==0) {
logprintf("attachtty","closed connection due to zero-length read");
close(sock); sock=-1;
}
}
if(ufds[1].revents & POLLHUP) {
logprintf("attachtty","closed connection due to hangup");
exit(0);
}
}
}
/*
create pipe
fork,
in child, manipulate fd so pipe reader=0
in child, start ssh
install sigint handler
normal usage: copy stdin to pipe writer
if sigint received, send \003 to pipe
*/
/* we do character-at-a-time copying into ssh, because speed is not
critical and I'm lazy */
void connect_ssh(char *host, char *path) {
int pipe_des[2];
int pid;
char buf[2];
if(pipe(&pipe_des)) bail("pipe");
pid=fork();
if(pid<0) { /* error */
bail("attachtty","Can't fork");
} else if(pid==0) { /* child */
setsid();
close(0);
dup2(pipe_des[0],0);
execlp("ssh", "ssh", host, "attachtty", path, NULL);
bail("attachtty", "exec failed");
} else { /* parent */
logprintf("attachtty","Successfully started");
while(! time_to_die) {
if(was_interrupted) {
buf[0]='\003';
write(pipe_des[1],buf,1);
was_interrupted=0;
}
if(read(0,buf,1) == 0) {
logprintf("attachtty","closed connection due to zero-length read");
time_to_die=SIGTERM;
}else
write(pipe_des[1],buf,1);
}
if(time_to_die==SIGCHLD) {
logprintf("attachtty","ssh exited, so closed connection");
} else {
kill(pid,SIGTERM); /* if it's still there, say goodbye */
}
/* don't worry about wait()ing for it, we're leaving anyway */
}
}
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