From http://www.jwz.org/xscreensaver/xscreensaver-5.35.tar.gz

[xscreensaver] / driver / stderr.c

diff --git a/driver/stderr.c b/driver/stderr.c
index 6246dd3a8e554fd8caa0e8486599283a571473a0..84fa697290d6268c34846fb36fb548ea56b8503a 100644 (file)
--- a/driver/stderr.c
+++ b/driver/stderr.c
@@ -1,5 +1,5 @@
 /* stderr.c --- capturing stdout/stderr output onto the screensaver window.
- * xscreensaver, Copyright (c) 1991-2006 Jamie Zawinski <jwz@jwz.org>
+ * xscreensaver, Copyright (c) 1991-2016 Jamie Zawinski <jwz@jwz.org>
  *
  * Permission to use, copy, modify, distribute, and sell this software and its
  * documentation for any purpose is hereby granted without fee, provided that
@@ -464,6 +464,7 @@ initialize_stderr (saver_info *si)
          perror ("could not dup() a new stdout:");
          return;
        }
+      close (out);
     }
 
   stderr_stdout_read_fd = in;
@@ -472,6 +473,47 @@ initialize_stderr (saver_info *si)
 }
 
 
+/* If the "-log file" command-line option has been specified,
+   open the file for append, and redirect stdout/stderr there.
+   This is called very early, before initialize_stderr().
+ */
+void
+stderr_log_file (saver_info *si)
+{
+  int stdout_fd = 1;
+  int stderr_fd = 2;
+  const char *filename = get_string_resource (si->dpy, "logFile", "LogFile");
+  int fd;
+
+  if (!filename || !*filename) return;
+
+  fd = open (filename, O_WRONLY | O_APPEND | O_CREAT, 0666);
+
+  if (fd < 0)
+    {
+      char buf[255];
+    FAIL:
+      sprintf (buf, "%.100s: %.100s", blurb(), filename);
+      perror (buf);
+      fflush (stderr);
+      fflush (stdout);
+      exit (1);
+    }
+
+  fprintf (stderr, "%s: logging to file %s\n", blurb(), filename);
+
+  if (dup2 (fd, stdout_fd) < 0) goto FAIL;
+  if (dup2 (fd, stderr_fd) < 0) goto FAIL;
+
+  fprintf (stderr, "\n\n"
+ "##########################################################################\n"
+           "%s: logging to \"%s\" at %s\n"
+ "##########################################################################\n"
+           "\n",
+           blurb(), filename, timestring(0));
+}
+
+
 /* If there is anything in the stderr buffer, flush it to the real stderr.
    This does no X operations.  Call this when exiting to make sure any
    last words actually show up.
@@ -487,8 +529,7 @@ shutdown_stderr (saver_info *si)
 
   stderr_callback ((XtPointer) si, &stderr_stdout_read_fd, 0);
 
-  if (stderr_buffer &&
-      stderr_tail &&
+  if (stderr_tail &&
       stderr_buffer < stderr_tail)
     {
       *stderr_tail = 0;
@@ -500,9 +541,20 @@ shutdown_stderr (saver_info *si)
   if (real_stderr) fflush (real_stderr);
 
   if (stdout != real_stdout)
-    dup2 (fileno(real_stdout), fileno(stdout));
+    {
+      dup2 (fileno(real_stdout), fileno(stdout));
+      fclose (real_stdout);
+      real_stdout = stdout;
+    }
   if (stderr != real_stderr)
-    dup2 (fileno(real_stderr), fileno(stderr));
-
-  stderr_stdout_read_fd = -1;
+    {
+      dup2 (fileno(real_stderr), fileno(stderr));
+      fclose (real_stderr);
+      real_stderr = stderr;
+    }
+  if (stderr_stdout_read_fd != -1)
+    {
+      close (stderr_stdout_read_fd);
+      stderr_stdout_read_fd = -1;
+    }
 }