dudki: initial import into svn repository

1 files changed, 184 insertions, 0 deletions

diff --git a/src/process.cc b/src/process.cc
new file mode 100644
index 0000000..fda35e8
--- a/dev/null
+++ b/src/process.cc
@@ -0,0 +1,184 @@
+#include <stdio.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <signal.h>
+#include <pwd.h>
+#include <grp.h>
+#include <sys/wait.h>
+#include <syslog.h>
+#include <errno.h>
+#include <iostream>
+#include <fstream>
+#include <stdexcept>
+using namespace std;
+#include "process.h"
+#include "configuration.h"
+
+void process::check(const string& id,configuration& config) {
+    bool running = false;
+    ifstream pids(pidfile.c_str(),ios::in);
+    if(pids) {
+	pid_t pid = 0;
+	pids >> pid;
+	pids.close();
+	if(pid) {
+	    if(!kill(pid,0)) {
+		running = true;
+	    }
+	}
+    }
+    if(running){
+	patience = 0;
+    }else{
+	if(patience>60) { // TODO: configurable
+	    patience = 0;
+	}else{
+	    if(patience<10) { // TODO: configurable
+		syslog(LOG_NOTICE,"The process '%s' is down, trying to launch.",id.c_str());
+		do_notify(id,"Starting up",
+			"The named process seems to be down. Dudki will try\n"
+			"to revive it by running the specified command.\n",
+			config);
+		try {
+		    launch(id,config);
+		}catch(exception& e) {
+		    syslog(LOG_ERR,"Error trying to launch process '%s': %s",id.c_str(),e.what());
+		}
+	    }else if(patience==10){ // TODO: configurable like the above
+		syslog(LOG_NOTICE,"Giving up on process '%s' for a while",id.c_str());
+		do_notify(id,"Giving up",
+			"After a number of attempts to relaunch the named process\n"
+			"It still seems to be down. Dudki is giving up attempts\n"
+			"to revive the process for a while.\n",
+			config);
+	    }
+	    patience++;
+	}
+    }
+}
+
+void process::launch(const string& id,configuration& config) {
+    uid_t uid = 0;
+    if(!user.empty()) {
+	struct passwd *ptmp = getpwnam(user.c_str());
+	if(ptmp) {
+	    uid = ptmp->pw_uid;
+	}else{
+	    errno=0;
+	    uid = strtol(user.c_str(),NULL,0);
+	    if(errno)
+		throw runtime_error("Failed to resolve User value to uid");
+	}
+    }
+    gid_t gid = 0;
+    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(!chroot.empty()) {
+		if(::chroot(chroot.c_str()))
+		    throw runtime_error(string(__PRETTY_FUNCTION__)+": failed to chroot()");
+	    }
+	    if(!group.empty()) {
+		// TODO: initgroups()?
+		if((getgid()!=gid) && setgid(gid))
+		    throw runtime_error(string(__PRETTY_FUNCTION__)+": failed to setgid()");
+	    }
+	    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
+    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
+}