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#include "coprocess.hh"
#include <stdlib.h>
#include <unistd.h>
#include <string>
#include <errno.h>
#include <signal.h>
#include <string.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <pdns/misc.hh>
#include <pdns/ahuexception.hh>
CoProcess::CoProcess(const string &command,int timeout, int infd, int outfd)
{
const char *argv[2];
argv[0]=strdup(command.c_str());
argv[1]=0;
launch(argv,timeout,infd,outfd);
}
CoProcess::CoProcess(const char **argv, int timeout, int infd, int outfd)
{
launch(argv,timeout,infd,outfd);
}
void CoProcess::launch(const char **argv, int timeout, int infd, int outfd)
{
d_timeout=timeout;
d_infd=infd;
d_outfd=outfd;
signal(SIGPIPE, SIG_IGN);
if(access(argv[0],X_OK)) // check before fork so we can throw
throw AhuException("Command '"+string(argv[0])+"' cannot be executed: "+stringerror());
if(pipe(d_fd1)<0 || pipe(d_fd2)<0)
throw AhuException("Unable to open pipe for coprocess: "+string(strerror(errno)));
if((d_pid=fork())<0)
throw AhuException("Unable to fork for coprocess: "+stringerror());
else if(d_pid>0) { // parent speaking
close(d_fd1[0]);
close(d_fd2[1]);
if(!(d_fp=fdopen(d_fd2[0],"r")))
throw AhuException("Unable to associate a file pointer with pipe: "+stringerror());
setbuf(d_fp,0); // no buffering please, confuses select
}
else if(!d_pid) { // child
close(d_fd1[1]);
close(d_fd2[0]);
if(d_fd1[0]!= infd) {
dup2(d_fd1[0], infd);
close(d_fd1[0]);
}
if(d_fd2[1]!= outfd) {
dup2(d_fd2[1], outfd);
close(d_fd2[1]);
}
// stdin & stdout are now connected, fire up our coprocess!
if(execv(argv[0], const_cast<char * const *>(argv))<0) // now what
exit(123);
/* not a lot we can do here. We shouldn't return because that will leave a forked process around.
no way to log this either - only thing we can do is make sure that our parent catches this soonest! */
}
}
CoProcess::~CoProcess()
{
int status;
if(!waitpid(d_pid, &status, WNOHANG))
kill(d_pid, 9);
}
void CoProcess::checkStatus()
{
int status;
int ret=waitpid(d_pid, &status, WNOHANG);
if(ret<0)
throw AhuException("Unable to ascertain status of coprocess "+itoa(d_pid)+" from "+itoa(getpid())+": "+string(strerror(errno)));
else if(ret) {
if(WIFEXITED(status)) {
int ret=WEXITSTATUS(status);
throw AhuException("Coprocess exited with code "+itoa(ret));
}
if(WIFSIGNALED(status)) {
int sig=WTERMSIG(status);
string reason="CoProcess died on receiving signal "+itoa(sig);
#ifdef WCOREDUMP
if(WCOREDUMP(status))
reason+=". Dumped core";
#endif
throw AhuException(reason);
}
}
}
void CoProcess::send(const string &snd)
{
checkStatus();
string line(snd);
line.append(1,'\n');
unsigned int sent=0;
int bytes;
// writen routine - socket may not accept al data in one go
while(sent<line.size()) {
bytes=write(d_fd1[1],line.c_str()+sent,line.length()-sent);
if(bytes<0)
throw AhuException("Writing to coprocess failed: "+string(strerror(errno)));
sent+=bytes;
}
}
void CoProcess::receive(string &receive)
{
char line[1024];
memset(line,0,1024);
if(d_timeout) {
struct timeval tv={tv_sec: d_timeout, tv_usec: 0,};
fd_set rds;
FD_ZERO(&rds);
FD_SET(fileno(d_fp),&rds);
int ret=select(fileno(d_fp)+1,&rds,0,0,&tv);
if(ret<0)
throw AhuException("Error waiting on data from coprocess: "+stringerror());
if(!ret)
throw AhuException("Timeout waiting for data from coprocess");
}
if(!fgets(line,1023,d_fp))
throw AhuException("Child closed pipe");
char *p;
if((p=strrchr(line,'\n')))
*p=0;
receive=line;
}
void CoProcess::sendReceive(const string &snd, string &rcv)
{
checkStatus();
send(snd);
receive(rcv);
}
#ifdef TESTDRIVER
main()
{
try {
CoProcess cp("./irc.pl");
string reply;
cp.sendReceive("www.trilab.com", reply);
cout<<"Answered: '"<<reply<<"'"<<endl;
}
catch(AhuException &ae) {
cerr<<ae.reason<<endl;
}
}
#endif
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