Change apr_proc_detach to take a parameter that can enable/disable automatic

forking (aka, to "daemonize").

Detailed explanation: If we are only interested in detaching from the
controlling terminal, then we are only interested in creating a new
process group (or creating a new session, which implicitly creates a
new process group). In order to do so, we must _NOT_ already be
a process group leader. The only way to ensure that is true, we normally
will call fork() and allow the parent to exit, ensuring that the child
is at least a child of a process group leader (and not one itself).

Doing this by default prevents some process-watching tools from working
with Apache. Therefore, when calling apr_proc_detach with
APR_PROC_DETACH_FOREGROUND, the caller is taking responsibility
for _NOT_ being a process group leader, which is guaranteed by
such process management tools.

[A similiar patch was originally submitted Jos and later modifed by Aaron.]

Obtained from:  Jos Backus <josb@cncdsl.com>
Submitted by:	Aaron Bannert


git-svn-id: https://svn.apache.org/repos/asf/apr/apr/trunk@63044 13f79535-47bb-0310-9956-ffa450edef68

5 files changed, 27 insertions, 17 deletions

diff --git a/include/apr_thread_proc.h b/include/apr_thread_proc.h
index d8598e0f3..d6e01aab9 100644
--- a/include/apr_thread_proc.h
+++ b/include/apr_thread_proc.h
@@ -578,10 +578,16 @@ APR_DECLARE(apr_status_t) apr_proc_wait_all_procs(apr_proc_t *proc,
                                                   apr_wait_how_e waithow,
                                                   apr_pool_t *p);
 
+#define APR_PROC_DETACH_FOREGROUND 0
+#define APR_PROC_DETACH_DAEMONIZE 1
+
 /**
  * Detach the process from the controlling terminal.
+ * @param daemonize set to non-zero if the process should daemonize
+ *                  and become a background process, else it will
+ *                  stay in the foreground.
  */
-APR_DECLARE(apr_status_t) apr_proc_detach(void);
+APR_DECLARE(apr_status_t) apr_proc_detach(int daemonize);
 
 #if APR_HAS_OTHER_CHILD
 
diff --git a/threadproc/netware/procsup.c b/threadproc/netware/procsup.c
index e7a3d69a4..daa1b8dc7 100644
--- a/threadproc/netware/procsup.c
+++ b/threadproc/netware/procsup.c
@@ -54,7 +54,7 @@
 
 #include "threadproc.h"
 
-apr_status_t apr_proc_detach(void)
+apr_status_t apr_proc_detach(int daemonize)
 {
 #if 0
     int x;
diff --git a/threadproc/os2/proc.c b/threadproc/os2/proc.c
index 08af08794..fdb2841ca 100644
--- a/threadproc/os2/proc.c
+++ b/threadproc/os2/proc.c
@@ -622,7 +622,7 @@ APR_DECLARE(apr_status_t) apr_get_os_proc(apr_os_proc_t *theproc, apr_proc_t *pr
 
 
 
-APR_DECLARE(apr_status_t) apr_proc_detach()
+APR_DECLARE(apr_status_t) apr_proc_detach(int daemonize)
 {
     return APR_ENOTIMPL;
 }
diff --git a/threadproc/unix/proc.c b/threadproc/unix/proc.c
index ff80f2cfe..deb188a58 100644
--- a/threadproc/unix/proc.c
+++ b/threadproc/unix/proc.c
@@ -362,26 +362,26 @@ APR_DECLARE(apr_status_t) apr_proc_create(apr_proc_t *new, const char *progname,
             }
             newargs[i + 2] = NULL;
             if (attr->detached) {
-                apr_proc_detach();
+                apr_proc_detach(APR_PROC_DETACH_DAEMONIZE);
             }
             execve(SHELL_PATH, (char * const *) newargs, (char * const *)env);
         }
         else if (attr->cmdtype == APR_PROGRAM) {
             if (attr->detached) {
-                apr_proc_detach();
+                apr_proc_detach(APR_PROC_DETACH_DAEMONIZE);
             }
             execve(progname, (char * const *)args, (char * const *)env);
         }
         else if (attr->cmdtype == APR_PROGRAM_ENV) {
             if (attr->detached) {
-                apr_proc_detach();
+                apr_proc_detach(APR_PROC_DETACH_DAEMONIZE);
             }
             execv(progname, (char * const *)args);
         }
         else {
             /* APR_PROGRAM_PATH */
             if (attr->detached) {
-                apr_proc_detach();
+                apr_proc_detach(APR_PROC_DETACH_DAEMONIZE);
             }
             execvp(progname, (char * const *)args);
         }
diff --git a/threadproc/unix/procsup.c b/threadproc/unix/procsup.c
index b96cb48ec..391f803bd 100644
--- a/threadproc/unix/procsup.c
+++ b/threadproc/unix/procsup.c
@@ -54,24 +54,28 @@
 
 #include "threadproc.h"
 
-APR_DECLARE(apr_status_t) apr_proc_detach(void)
+APR_DECLARE(apr_status_t) apr_proc_detach(int daemonize)
 {
     int x;
     pid_t pgrp;
 
     chdir("/");
 #if !defined(MPE) && !defined(OS2) && !defined(TPF) && !defined(BEOS)
-/* Don't detach for MPE because child processes can't survive the death of
-   the parent. */
-    if ((x = fork()) > 0)
-        exit(0);
-    else if (x == -1) {
-        perror("fork");
-        fprintf(stderr, "unable to fork new process\n");
-        exit(1);  /* we can't do anything here, so just exit. */
+    /* Don't detach for MPE because child processes can't survive the death of
+     * the parent. */
+    if (daemonize) {
+	    if ((x = fork()) > 0) {
+	        exit(0);
+        }
+	    else if (x == -1) {
+	        perror("fork");
+	        fprintf(stderr, "unable to fork new process\n");
+	        exit(1);  /* we can't do anything here, so just exit. */
+	    }
+	    /* RAISE_SIGSTOP(DETACH); */
     }
-/*    RAISE_SIGSTOP(DETACH);*/
 #endif
+
 #ifdef HAVE_SETSID
     if ((pgrp = setsid()) == -1) {
         return errno;