Sun Oct 24 12:14:07 PDT 1999

(KainX)

Lock files now store PID's so that stale checks can be made.  It seems to
work here, but I'll need lots of testing.

PLEASE remove all .lock files from ~/.enlightenment/epplet_config/*/ and close
all running epplets before running any new ones!


SVN revision: 963

ChangeLog

@@ -67,3 +67,14 @@ Sat Oct 23 21:00:30 PDT 1999
 (Mandrake)
 
 Second patch from horms about popup entry removal
+
+-------------------------------------------------------------------------------
+
+Sun Oct 24 12:14:07 PDT 1999
+(KainX)
+
+Lock files now store PID's so that stale checks can be made.  It seems to
+work here, but I'll need lots of testing.
+
+PLEASE remove all .lock files from ~/.enlightenment/epplet_config/*/ and close
+all running epplets before running any new ones!

api/epplet.c

@@ -3712,10 +3712,8 @@ Epplet_find_instance(char *name)
 {
   struct stat st;
   char s[1024];
-  int i = 0;
-  FILE *fp;
-
-  epplet_instance = 1;
+  int i = 0, fd;
+  pid_t pid;
 
   /* make sure basic dir exists */
   sprintf(s, "%s/.enlightenment/epplet_config", getenv("HOME"));
@@ -3728,6 +3726,8 @@ Epplet_find_instance(char *name)
 	  sprintf(err, "Unable to create epplet config directory %s -- %s.\n",
 		  s, strerror(errno));
 	  Epplet_dialog_ok(err);
+	  epplet_instance = 1;
+	  return;
 	}
     }
 
@@ -3743,28 +3743,70 @@ Epplet_find_instance(char *name)
 	  sprintf(err, "Unable to create epplet config directory %s -- %s.\n",
 		  s, strerror(errno));
 	  Epplet_dialog_ok(err);
+	  epplet_instance = 1;
+	  return;
 	}
     }
 
-  /* find out instance */
-  do
+  /* Pick our instance number.  255 is the max to avoid infinite loops, which could be caused by
+     lack of insert permissions in the config directory. */
+  for (i = 1; i < 256; i++)
     {
-      i++;
       sprintf(s, "%s/.lock_%i", conf_dir, i);
+      if (stat(s, &st) >= 0)
+	{
+	  /* Lock file exists.  Read from it. */
+	  if ((fd = open(s, O_RDONLY)) < 0)
+	    {
+	      /* Either it's there and we can't read it, or it's gone now.  Next! */
+	      fprintf(stderr, "Unable to read lock file %s -- %s\n", s, strerror(errno));
+	      continue;
+	    }
+	  if ((read(fd, &pid, sizeof(pid_t))) < ((int) sizeof(pid_t)))
+	    {
+	      /* We didn't get enough bytes.  Next! */
+	      fprintf(stderr, "Read attempt for lock file %s failed -- %s\n", s, strerror(errno));
+	      continue;
+	    }
+	  if (pid <= 0)
+	    {
+	      /* We got a bogus process ID.  Next! */
+	      fprintf(stderr, "Lock file %s contained a bogus process ID (%lu)\n", s, (unsigned long) pid);
+	      continue;
+	    }
+	  if ((kill(pid, 0) == 0) || (errno != ESRCH))
+	    {
+	      /* The process exists.  Next! */
+	      continue;
+	    }
+	  /* Okay, looks like a stale lockfile at this point.  Remove it. */
+	  if ((unlink(s)) != 0)
+	    {
+	      /* Removal failed.  Next! */
+	      fprintf(stderr, "Unable to remove stale lock file %s -- %s.  Please remove it manually.\n",
+		      s, strerror(errno));
+	      continue;
+	    }
+	}
+      if ((fd = open(s, (O_WRONLY | O_EXCL | O_CREAT))) < 0)
+	{
+	  /* Apparently another process just came in under us and created it.  Next! */
+	  continue;
+	}
+      pid = getpid();
+      write(fd, &pid, sizeof(pid_t));  /* Not sure how best to deal with write errors here */
+      close(fd);
+      /* If we made it here, we've just written the lock file and saved it.  We have our instance
+	 number, so exit the loop. */
+      break;
     }
-  while (stat(s, &st) >= 0);
-  epplet_instance = i;
-  
-  /* create lock file */
-  if (!(fp = fopen(s, "w")))
+
+  /* Anything this high is probably an error. */
+  if (i >= 255)
     {
-      char err[255];
-      
-      sprintf(err, "Unable to create lock file %s -- %s.\n", s, strerror(errno));
-      Epplet_dialog_ok(err);
+      i = 1;
     }
-  else
-    fclose(fp);
+  epplet_instance = i;
   
   /* find out epplet's name */
   if (epplet_instance > 1)