Just curious but what is wrong with just writing a program that doesn't
put out any text to the console and starting it with a script with a
command like this:
mydaemon&
Besides the fact that it's a little less elegant?
It's been a long long time since I did C/C++ coding and righting
daemons. I'm planning on writing up a little tcp/ip daemon for my
Zaurus. Thanks for any input.
-David
On Thu, 2002-05-23 at 19:13, M. Mueller wrote:
> On Thursday 23 May 2002 06:40 pm, Peter Long reputedly wrote:
>
> > Hi all,
> >
> > I have a console application that I want to turn into a daemon. Does anyone
> > know where I can find documentation on how to do that.
> >
> > Thanks in advance.
>
>
> Here's my daemon launcher. It is more than a basic daemon launcher because I
> have N daemons that all talk to each other. Furthermore, I don't want any
> daemons to start doing business until all the other daemons are ready.
>
> --
> Mike Mueller
> www.ss7box.com
> ----
>
> #include <sys/stat.h>
> #include <sys/msg.h>
> #include <fcntl.h>
> #include <syslog.h>
> #include <stdio.h>
> #include <unistd.h>
> #include <errno.h>
> #include "ipc_mq.h"
>
> #define MAX_DAEMONS 5
> #define DAEMON_PATH "usr/local/ss7t/bin/"
>
> char *env_init[] = {"USER=mtp3d", "PATH=/tmp", NULL};
> char *daemon_names[][MAX_DAEMONS] = {
> "mtp3_d",
> "tali_d",
> // "sctp_d",
> "oam_d",
> "mr_d",
> "ps_d"
> };
>
> int sockfd;
> struct sockaddr_in myaddr, peeraddr;
> t_ipc_mqbuf mb;
> socklen_t sockaddrlen;
>
> void get_busy (unsigned int daemon_id)
> /******************************************************************************
> ******************************************************************************/
> {
> int r;
>
> bzero(&peeraddr, sizeof(peeraddr));
> peeraddr.sin_family = AF_INET;
> peeraddr.sin_port = htons(daemon_id);
> r = inet_pton(AF_INET, IPC_ADDR_STR, &peeraddr.sin_addr.s_addr);
> if (r == -1)
> {
> syslog (LOG_INFO, "F:daemon_launcher:get_busy:inet_pton failed:%s",
> strerror(errno));
> exit (-1);
> }
>
> bzero (&mb, sizeof(mb));
> mb.mhdr.s_id = DLAUNCH_ID; // this is the letter sender
> mb.mhdr.mcode = IPC_PROCEED;
> mb.mhdr.mlen = sizeof(t_ipc_mb_hdr);
>
> r = sendto (sockfd, &mb, mb.mhdr.mlen, NOFLAGS,
> &peeraddr, sizeof (peeraddr));
> if (r == -1)
> {
> syslog (LOG_INFO, "F:get busy:sendto failed:cause %s target: %s",
> strerror(errno), daemon_id);
> exit (-1);
> }
> }
>
> int daemon_init(char *p_daemon_fname)
> /******************************************************************************
> ******************************************************************************/
> {
> char daemon_pathname [128];
> pid_t pid;
>
> if ( (pid = fork()) < 0)
> return(-1);
> else if (pid != 0)
> return (0); /* the parent process returns from this function here
>*/
>
> // the child process continues here
>
> setsid(); /* become session leader */
> chdir("/"); /* change working directory */
> umask(0); /* clear our file mode creation mask */
>
> if ((strlen (p_daemon_fname) + strlen (DAEMON_PATH)+ 1) > sizeof
>(daemon_pathname))
> {
> syslog (LOG_INFO, "daemon pathname too long");
> exit (-1);
> }
>
> // exec the daemon in the child process
>
> execl (
> strcat (strcpy (daemon_pathname,DAEMON_PATH), p_daemon_fname),
> p_daemon_fname,
> (char *) 0
> );
>
> // should never reach this statement
>
> exit(0);
> }
>
> int daemon_comm_ready (void)
> /******************************************************************************
> ******************************************************************************/
> {
> ssize_t bw;
> u_long daemons_ready;
>
> daemons_ready = 0;
>
> for (;;)
> {
> // blocking read; wait for a daemon to report for duty; if this becomes
> // a block-forever condition, then one must resort to killing process
> // use "ps -axj" as superuser to find the processes to be killed
>
> bw = recvfrom (sockfd, &mb, sizeof (mb), NOFLAGS,
> &peeraddr, &sockaddrlen);
> if (bw == -1)
> {
> syslog (LOG_INFO, "F:daemon_comm_ready:recvfrom failed");
> exit (-1);
> }
>
> // show who's ready for duty; add a string termination
>
> //mb.mdata[mb.mhdr.mlen - sizeof(t_ipc_mb_hdr)] = '\0';
> syslog (LOG_INFO, "I:mb contents:s_id %d daemon on duty: %s",
> mb.mhdr.s_id,
> &mb.mdata);
>
> daemons_ready = daemons_ready | mb.mhdr.s_id;
> if (daemons_ready == ALL_DAEMONS_READY)
> {
> syslog (LOG_INFO, "I:daemon_comm_ready:all daemons ready");
> break;
> }
> } // end of for loop
>
> // tell the daemons that IPC may proceed
>
> get_busy (MTP3_PORT);
> get_busy (TALI_PORT);
> // get_busy (SCTP_IPC_PORT);
> get_busy (OAM_PORT);
> get_busy (MR_PORT);
> get_busy (PS_PORT);
> }
>
> int configure_dl()
> /******************************************************************************
> ******************************************************************************/
> {
> //dlConf = new c_confReader("dl");
> //delete dlConf
> }
>
> int main (int argc, char **argv)
> /******************************************************************************
> ******************************************************************************/
> {
> int d;
> int r;
>
> openlog ("daemon_init" ,LOG_PID, LOG_USER);
> syslog (LOG_INFO ,"Daemon launcher starting");
>
> // read daemon launcher conf file
>
> configure_dl();
>
> sockfd = socket(AF_INET, SOCK_DGRAM, 0);
> if (sockfd == -1)
> {
> syslog (LOG_INFO, "socket failed");
> exit (-1);
> }
>
> // create an Internet Protocol address
>
> bzero(&myaddr, sizeof(myaddr));
> myaddr.sin_family = AF_INET;
> myaddr.sin_port = htons(DLAUNCH_PORT);
> r = inet_pton(AF_INET, IPC_ADDR_STR, &myaddr.sin_addr.s_addr);
> if (r == -1)
> {
> syslog (LOG_INFO, "I:daemon_launcher:main:inet_pton failed:%s",
> strerror(errno));
> exit (-1);
> }
>
> r = bind (sockfd, (const struct sockaddr *) &myaddr, sizeof(myaddr));
> if (r == -1)
> {
> syslog (LOG_INFO, "bind failed");
> exit (-1);
> }
>
> for (d = 0; d < MAX_DAEMONS; d++)
> {
> if (daemon_init (daemon_names [0][d]) == -1)
> {
> syslog (LOG_INFO, "fork failed; daemon ID: %s\n",
>daemon_names[d]);
> return (-1);
> }
> }
>
> if (daemon_comm_ready () == -1)
> {
> }
> return (0);
> }
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