mdmon: fork and run as a daemon.

[thirdparty/mdadm.git] / mdmon.c

diff --git a/mdmon.c b/mdmon.c
index c7d7f680db574c31fb58b5c627e05b8f08432b56..d35c05b2d7a9ac779610b3cc932627d318ccdec2 100644 (file)
--- a/mdmon.c
+++ b/mdmon.c
@@ -32,6 +32,7 @@
 #include       <sys/un.h>
 #include       <sys/mman.h>
 #include       <sys/syscall.h>
+#include       <sys/wait.h>
 #include       <stdio.h>
 #include       <errno.h>
 #include       <string.h>
@@ -175,6 +176,8 @@ int main(int argc, char *argv[])
        struct supertype *container;
        sigset_t set;
        struct sigaction act;
+       int pfd[2];
+       int status;
 
        if (argc != 2) {
                fprintf(stderr, "Usage: md-manage /device/name/for/container\n");
@@ -192,6 +195,24 @@ int main(int argc, char *argv[])
                exit(1);
        }
 
+       /* Fork, and have the child tell us when they are ready */
+       pipe(pfd);
+       switch(fork()){
+       case -1:
+               fprintf(stderr, "mdmon: failed to fork: %s\n",
+                       strerror(errno));
+               exit(1);
+       case 0: /* child */
+               close(pfd[0]);
+               break;
+       default: /* parent */
+               close(pfd[1]);
+               if (read(pfd[0], &status, sizeof(status)) != sizeof(status)) {
+                       wait(&status);
+                       status = WEXITSTATUS(status);
+               }
+               exit(status);
+       }
        /* hopefully it is a container - we'll check later */
 
        container = malloc(sizeof(*container));
@@ -268,6 +289,23 @@ int main(int argc, char *argv[])
                exit(3);
        }
 
+       /* Ok, this is close enough.  We can say goodbye to our parent now.
+        */
+       status = 0;
+       write(pfd[1], &status, sizeof(status));
+       close(pfd[1]);
+
+       chdir("/");
+       setsid();
+       close(0);
+       open("/dev/null", O_RDWR);
+       close(1);
+       dup(0);
+#ifndef DEBUG
+       close(2);
+       dup(0);
+#endif
+
        mlockall(MCL_FUTURE);
 
        /* SIGUSR is sent between parent and child.  So both block it