X-Git-Url: https://www.tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=lib%2Fdropin.c;h=5f4fcebd39135873b013da52e1d26b9b35e3d4c9;hp=faa2314bd90749ce7f948c0265dc2922122fc319;hb=1ca04711aeab615161746c6bbb5d137388c73263;hpb=c94f7637427f4c89d56c41fe4c75f2970b664a63

diff --git a/lib/dropin.c b/lib/dropin.c
index faa2314b..5f4fcebd 100644
--- a/lib/dropin.c
+++ b/lib/dropin.c
@@ -17,7 +17,7 @@
     along with this program; if not, write to the Free Software
     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 
-    $Id: dropin.c,v 1.1.2.1 2000/11/28 23:23:41 zarq Exp $
+    $Id: dropin.c,v 1.1.2.2 2000/11/29 00:33:15 zarq Exp $
 */
 
 #include "config.h"
@@ -28,9 +28,24 @@
 #include <unistd.h>
 #include <stdio.h>
 
+#include <xalloc.h>
+
 #include <system.h>
 
 #ifndef HAVE_DAEMON
+/*
+  Replacement for the daemon() function.
+  
+  The daemon() function is for programs wishing to detach themselves
+  from the controlling terminal and run in the background as system
+  daemons.
+
+  Unless the argument nochdir is non-zero, daemon() changes the
+  current working directory to the root (``/'').
+
+  Unless the argument noclose is non-zero, daemon() will redirect
+  standard input, standard output and standard error to /dev/null.
+*/
 int daemon(int nochdir, int noclose)
 {
   pid_t pid;
@@ -39,7 +54,6 @@ int daemon(int nochdir, int noclose)
   pid = fork();
   
   /* Check if forking failed */
-    
   if(pid < 0)
     {
       perror("fork");
@@ -47,27 +61,24 @@ int daemon(int nochdir, int noclose)
     }
 
   /* If we are the parent, terminate */
-  
   if(pid)
     exit(0);
 
   /* Detach by becoming the new process group leader */
-  
   if(setsid() < 0)
     {
       perror("setsid");
       return -1;
     }
   
-  /* Change working directory to the root (to avoid keeping mount points busy) */
-  
+  /* Change working directory to the root (to avoid keeping mount
+     points busy) */
   if(!nochdir)
     {
       chdir("/");
     }
     
   /* Redirect stdin/out/err to /dev/null */
-
   if(!noclose)
     {
       fd = open("/dev/null", O_RDWR);
@@ -77,7 +88,7 @@ int daemon(int nochdir, int noclose)
           perror("opening /dev/null");
           return -1;
         }
-        else
+      else
         {
           dup2(fd, 0);
           dup2(fd, 1);
@@ -90,12 +101,36 @@ int daemon(int nochdir, int noclose)
 
 
 
-
 #ifndef HAVE_GET_CURRENT_DIR_NAME
+/*
+  Replacement for the GNU get_current_dir_name function:
 
+  get_current_dir_name will malloc(3) an array big enough to hold the
+  current directory name.  If the environment variable PWD is set, and
+  its value is correct, then that value will be returned.
+*/
 char *get_current_dir_name(void)
 {
-  return ".";
-}
+  size_t size;
+  char *buf;
+
+  /* Start with 100 bytes.  If this turns out to be insufficient to
+     contain the working directory, double the size.  */
+  size = 100;
+  buf = xmalloc(size);
+
+  errno = 0; /* Success */
+  r = getcwd(buf, size);
+  /* getcwd returns NULL and sets errno to ERANGE if the bufferspace
+     is insufficient to contain the entire working directory.  */
+  while(r == NULL && errno = ERANGE)
+    {
+      free(buf);
+      size <<= 1; /* double the size */
+      buf = xmalloc(size);
+      r = getcwd(buf, size);
+    }
 
+  return buf;
+}
 #endif