don't break in the absence of sendmail

If for whatever reason notify child isn't properly spawned, don't die and still
try to launch process in question

Signed-off-by: Michael Krelin <hacker@klever.net>

1 files changed, 6 insertions, 1 deletions

diff --git a/src/process.cc b/src/process.cc
index 6d3b2a2..4807b98 100644
--- a/src/process.cc
+++ b/src/process.cc
@@ -77,211 +77,216 @@ void process::launch(const string& id,configuration& config) {
 		throw runtime_error("Failed to resolve User value to uid");
 	}
     }
     if(!group.empty()) {
 	struct group *gtmp = getgrnam(group.c_str());
 	if(gtmp) {
 	    gid = gtmp->gr_gid;
 	}else{
 	    errno = 0;
 	    gid = strtol(group.c_str(),NULL,0);
 	    if(errno)
 		throw runtime_error("Failed to reslove Group value to gid");
 	}
     }
     pid_t p = fork();
     if(p<0)
 	throw runtime_error(string(__PRETTY_FUNCTION__)+": failed to fork()");
     if(!p) {
 	// child
 	try {
 	    setsid();
 	    if(!group.empty()) {
 		if(user.empty()) {
 		    if((getgid()!=gid) && setgid(gid))
 			throw runtime_error(string(__PRETTY_FUNCTION__)+": failed to setgid()");
 		}else{
 		    if(initgroups(user.c_str(),gid))
 			throw runtime_error(string(__PRETTY_FUNCTION__)+": failed to initgroups()");
 		}
 	    }
 	    if(!chroot.empty()) {
 		if(::chroot(chroot.c_str()))
 		    throw runtime_error(string(__PRETTY_FUNCTION__)+": failed to chroot()");
 	    }
 	    if(!user.empty()) {
 		if((getuid()!=uid) && setuid(uid))
 		    throw runtime_error(string(__PRETTY_FUNCTION__)+": failed to setuid()");
 	    }
 	    char *argv[] = { "/bin/sh", "-c", (char*)restart_cmd.c_str(), NULL };
 	    close(0); close(1); close(2);
 	    execv("/bin/sh",argv);
 	}catch(exception& e) {
 	    syslog(LOG_ERR,"Error trying to launch process '%s': %s",id.c_str(),e.what());
 	}
 	_exit(-1);
     }
     // parent
     int rv;
     if(waitpid(p,&rv,0)<0)
 	throw runtime_error(string(__PRETTY_FUNCTION__)+": failed to waitpid()");
 }
 
 void process::do_notify(const string& id,const string& event,const string& description,configuration& config) {
     string the_notify;
     if(!notify.empty())
 	the_notify=notify;
     else if(!config.notify.empty())
 	the_notify=config.notify;
     else
 	return;
     try {
 	string::size_type colon = the_notify.find(':');
 	if(colon==string::npos)
 	    throw runtime_error("invalid notify action specification");
 	string nschema = the_notify.substr(0,colon);
 	string ntarget = the_notify.substr(colon+1);
 	if(nschema=="mailto") {
 	    notify_mailto(ntarget,id,event,description,config);
 	}else
 	    throw runtime_error("unrecognized notification schema");
     }catch(exception& e) {
 	syslog(LOG_ERR,"Notification error: %s",e.what());
     }
 }
 
 void process::notify_mailto(const string& email,const string& id,const string& event,const string& description,configuration& config) {
     int files[2];
     if(pipe(files))
 	throw runtime_error("Failed to pipe()");
     pid_t pid = vfork();
     if(pid==-1) {
 	close(files[0]);
 	close(files[1]);
 	throw runtime_error("Failed to vfork()");
     }
     if(!pid) {
 	// child
 	if(dup2(files[0],0)!=0)
 	    _exit(-1);
 	close(1);
 	close(files[0]);
 	close(files[1]);
 	execl("/usr/sbin/sendmail","usr/sbin/sendmail","-i",email.c_str(),NULL);
 	_exit(-1);
     }
     // parent
+    int status;
+    if(waitpid(pid,&status,WNOHANG)) {
+	close(files[0]);
+	close(files[1]);
+	throw runtime_error("vfork()ed sendmail child exited unexpectedly");
+    }
     close(files[0]);
     FILE *mta = fdopen(files[1],"w");
     for(headers_t::const_iterator i=mailto_headers.begin();i!=mailto_headers.end();++i) {
 	fprintf(mta,"%s: %s\n",i->first.c_str(),i->second.c_str());
     }
     for(headers_t::const_iterator i=config.mailto_headers.begin();i!=config.mailto_headers.end();++i) {
 	if(mailto_headers.find(i->first)!=mailto_headers.end())
 	    continue;
 	fprintf(mta,"%s: %s\n",i->first.c_str(),i->second.c_str());
     }
     fprintf(mta,
 	    "Subject: [%s] %s\n\n"
 	    "%s\n"
 	    "---\n"
 	    "This message was sent automatically by the 'dudki' daemon\n",
 	    id.c_str(), event.c_str(),
 	    description.c_str() );
     fclose(mta);
-    int status;
     waitpid(pid,&status,0);
     // TODO: check the return code
 }
 
 void process::signal(int signum) const {
     if(!pidfile.empty()) {
 	ifstream pids(pidfile.c_str(),ios::in);
 	if(!pids)
 	    throw runtime_error("no pidfile found");
 	pid_t pid = 0;
 	pids >> pid;
 	pids.close();
 	if(!pid)
 	    throw runtime_error("no pid in pidfile");
 	if(kill(pid,signum))
 	    throw runtime_error("failed to signal process");
     }else if(!process_name.empty()) {
 	if(procpids.empty())
 	    gather_proc_info();
 	pair<multimap<string,pid_t>::const_iterator,multimap<string,pid_t>::const_iterator> range = procpids.equal_range(process_name);
 	int count = 0;
 	for(multimap<string,pid_t>::const_iterator i=range.first;i!=range.second;++i) {
 	    pid_t pid = i->second;
 	    if(kill(i->second,signum))
 		throw runtime_error("failed to signal process");
 	    count++;
 	}
 	if(!count)
 	    throw runtime_error("no running instance detected");
     }else
 	throw runtime_error("nothing is known about the process");
 }
 
 void process::prepare_herd() {
     procpids.clear();
 }
 void process::unprepare_herd() {
     procpids.clear();
 }
 void process::gather_proc_info() {
     vector<pid_t> allpids;
     DIR *pd = opendir("/proc");
     if(!pd)
 	throw runtime_error("failed to open /proc");
     struct dirent *pde;
     pid_t selfpid = getpid();
     while(pde=readdir(pd)) {
 	errno=0;
 	pid_t pid = atoi(pde->d_name);
 	if((!pid) || pid==selfpid)
 	    continue;
 	allpids.push_back(pid);
     }
     closedir(pd);
     char s[256];
     procpids.clear();
     for(vector<pid_t>::const_iterator i=allpids.begin();i!=allpids.end();++i) {
 	int r = snprintf(s,sizeof(s),"/proc/%d/stat",*i);
 	if(r>=sizeof(s) || r<1)
 	    continue;
 	string cmd;
 	ifstream ss(s,ios::in);
 	if(ss) {
 	    getline(ss,cmd);
 	    string::size_type op = cmd.find('(');
 	    if(op==string::npos)
 		continue;
 	    cmd.erase(0,op+1);
 	    string::size_type cp = cmd.find(')');
 	    if(cp==string::npos)
 		continue;
 	    cmd.erase(cp);
 	}else{
 	    r = snprintf(s,sizeof(s),"/proc/%d/status",*i);
 	    if(r>=sizeof(s) || r<1)
 		continue;
 	    ifstream ss(s,ios::in);
 	    if(!ss)
 		continue;
 	    ss >> cmd;
 	    if(cmd.empty())
 		continue;
 	}
 	r = snprintf(s,sizeof(s),"/proc/%d/cmdline",*i);
 	if(r>=sizeof(s) || r<1)
 	    continue;
 	ifstream cs(s,ios::binary);
 	if(!cs)
 	    continue;
 	string command;
 	while(cs) {
 	    string cl;
 	    getline(cs,cl,(char)0);
 	    string::size_type lsl = cl.rfind('/');
 	    if(lsl!=string::npos)
 		cl.erase(0,lsl+1);