r32: keep track of children and send them SIGTERM if someone sends us that;

invoke daemon() before we do anything.

diff --git a/nbd-server.c b/nbd-server.c
index 0821422..e19a381 100644 (file)
--- a/nbd-server.c
+++ b/nbd-server.c
@@ -26,9 +26,14 @@
  *     _FILE_OFFSET_BITS=64 and _LARGEFILE_SOURCE if you used to be
  *     using FS_32BIT. This will allow you to use files >2GB instead of
  *     having to use the -m option. Wouter Verhelst <wouter@debian.org>
+ * Version 2.4 - Added code to keep track of children, so that we can
+ *     properly kill them from initscripts. Add a call to daemon(),
+ *     so that processes don't think they have to wait for us, which is
+ *     interesting for initscripts as well. Wouter Verhelst
+ *     <wouter@debian.org>
  */
 
-#define VERSION "2.3"
+#define VERSION PACKAGE_VERSION
 #define GIGA (1*1024*1024*1024)
 
 #include <sys/types.h>
@@ -56,6 +61,10 @@
    clients authorized to use the server. If it does not exist,
    access is permitted. */
 #define AUTH_FILE "nbd_server.allow"
+/* how much space for child PIDs we have by default. Dynamically
+   allocated, and will be realloc()ed if out of space, so this should
+   probably be fair for most situations. */
+#define DEFAULT_CHILD_ARRAY 256
 
 #include "cliserv.h"
 //#undef _IO
@@ -117,7 +126,6 @@ int authorized_client(char *name)
   return 0 ;
 }
 
-
 inline void readit(int f, void *buf, int len)
 {
        int res;
@@ -157,7 +165,8 @@ int difffile=-1 ;
 u32 difffilelen=0 ; /* number of pages in difffile */
 u32 *difmap=NULL ;
 char clientname[256] ;
-
+int child_arraysize=DEFAULT_CHILD_ARRAY;
+pid_t *children;
 
 #define DIFFPAGESIZE 4096 /* diff file uses those chunks */
 
@@ -227,7 +236,35 @@ void cmdline(int argc, char *argv[])
 
 void sigchld_handler(int s)
 {
-       while(wait(NULL) > 0);
+        int* status=NULL;
+       int i;
+       pid_t pid;
+
+       while((pid=wait(status)) > 0) {
+               if(WIFEXITED(status)) {
+                       msg3(LOG_INFO, "Child exited with %d", WEXITSTATUS(status));
+               }
+               for(i=0;children[i]!=pid&&i<child_arraysize;i++);
+               if(i>=child_arraysize) {
+                       msg3(LOG_INFO, "SIGCHLD received for an unknown child with PID %ld",(long) pid);
+               } else {
+                       children[i]=(pid_t)0;
+                       DEBUG2("Removing %d from the list of children", pid);
+               }
+       }
+}
+
+/* If we are terminated, make sure our children are, too. */
+void sigterm_handler(int s) {
+       int i;
+
+       for(i=0;i<child_arraysize;i++) {
+               if(children[i]) {
+                       kill(children[i], s);
+               }
+       }
+
+       exit(0);
 }
 
 void connectme(int port)
@@ -235,7 +272,7 @@ void connectme(int port)
        struct sockaddr_in addrin;
        struct sigaction sa;
        int addrinlen = sizeof(addrin);
-       int net, sock, newpid;
+       int net, sock, newpid, i;
 #ifndef sun
        int yes=1;
 #else
@@ -265,30 +302,52 @@ void connectme(int port)
        sa.sa_flags = SA_RESTART;
        if(sigaction(SIGCHLD, &sa, NULL) == -1)
                err("sigaction: %m");
+       sa.sa_handler = sigterm_handler;
+       sigemptyset(&sa.sa_mask);
+       sa.sa_flags = SA_RESTART;
+       if(sigaction(SIGTERM, &sa, NULL) == -1)
+               err("sigaction: %m");
+       children=malloc(sizeof(pid_t)*child_arraysize);
+       memset(children, 0, sizeof(pid_t)*DEFAULT_CHILD_ARRAY);
+#ifndef NODAEMON
+#ifndef NOFORK
+       if(daemon(1,0)<0) {
+               err("daemon");
+       }
+#endif /* NOFORK */
+#endif /* NODAEMON */
        for(;;) { /* infinite loop */
-         if ((net = accept(sock, (struct sockaddr *) &addrin, &addrinlen)) < 0)
-           err("accept: %m");
-
-         set_peername(net,clientname) ;
-         if (!authorized_client(clientname)) {
-           msg2(LOG_INFO,"Unauthorized client") ;
-           close(net) ;
-           continue ;
-         }
-         msg2(LOG_INFO,"Authorized client") ;
+               if ((net = accept(sock, (struct sockaddr *) &addrin, &addrinlen)) < 0)
+                       err("accept: %m");
+               
+               set_peername(net,clientname) ;
+               if (!authorized_client(clientname)) {
+                       msg2(LOG_INFO,"Unauthorized client") ;
+                       close(net) ;
+                       continue ;
+               }
+               msg2(LOG_INFO,"Authorized client") ;
+               for(i=0;children[i]&&i<child_arraysize;i++);
+               if(i>=child_arraysize) {
+                       realloc(children, sizeof(pid_t)*child_arraysize);
+                       memset(children+child_arraysize, 0, sizeof(pid_t)*DEFAULT_CHILD_ARRAY);
+                       i=child_arraysize+1;
+                       child_arraysize+=DEFAULT_CHILD_ARRAY;
+               }
 #ifndef NOFORK
-         if ((newpid=fork())<0) {
-           msg3(LOG_INFO,"Could not fork (%s)",strerror(errno)) ;
-           close(net) ;
-           continue ;
-         }
-         if (newpid>0) { /* parent */
-           close(net) ; continue ; }
-         /* child */
-         close(sock) ;
+               if ((children[i]=fork())<0) {
+                       msg3(LOG_INFO,"Could not fork (%s)",strerror(errno)) ;
+                       close(net) ;
+                       continue ;
+               }
+               if (children[i]>0) { /* parent */
+                       close(net) ; continue ; }
+               /* child */
+               realloc(children,0);
+               close(sock) ;
 #endif // NOFORK
-         msg2(LOG_INFO,"Starting to serve") ;
-         serveconnection(net) ;        
+               msg2(LOG_INFO,"Starting to serve") ;
+               serveconnection(net) ;        
        }
 }
 
@@ -427,7 +486,6 @@ int mainloop(int net)
 #define BUFSIZE (1024*1024)
                char buf[BUFSIZE];
                int len;
-
 #ifdef DODBG
                i++;
                printf("%d: ", i);