ftp://ftp.krokus.ru/pub/OpenBSD/distfiles/xscreensaver-5.01.tar.gz

[xscreensaver] / driver / subprocs.c

diff --git a/driver/subprocs.c b/driver/subprocs.c
index b6948e8789c30dd8c8c025f79eeafa1d7a568c27..0bbe4a87609c836239b693642957276d33f64a89 100644 (file)
--- a/driver/subprocs.c
+++ b/driver/subprocs.c
@@ -1,5 +1,5 @@
 /* subprocs.c --- choosing, spawning, and killing screenhacks.
 /* subprocs.c --- choosing, spawning, and killing screenhacks.

- * xscreensaver, Copyright (c) 1991-2003 Jamie Zawinski <jwz@jwz.org>
+ * xscreensaver, Copyright (c) 1991-2006 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
  *
  * Permission to use, copy, modify, distribute, and sell this software and its
  * documentation for any purpose is hereby granted without fee, provided that


@@ -25,6 +25,7 @@
 #endif
 
 #include <sys/time.h>          /* sys/resource.h needs this for timeval */
 #endif
 
 #include <sys/time.h>          /* sys/resource.h needs this for timeval */

+#include <sys/param.h>         /* for PATH_MAX */

 
 #ifdef HAVE_SYS_WAIT_H
 # include <sys/wait.h>         /* for waitpid() and associated macros */
 
 #ifdef HAVE_SYS_WAIT_H
 # include <sys/wait.h>         /* for waitpid() and associated macros */


@@ -65,12 +66,66 @@ extern int kill (pid_t, int);               /* signal() is in sys/signal.h... */
 #define Widget       void*
 
 #include "xscreensaver.h"
 #define Widget       void*
 
 #include "xscreensaver.h"

+#include "exec.h"

 #include "yarandom.h"
 #include "visual.h"    /* for id_to_visual() */
 
 extern saver_info *global_si_kludge;   /* I hate C so much... */
 
 
 #include "yarandom.h"
 #include "visual.h"    /* for id_to_visual() */
 
 extern saver_info *global_si_kludge;   /* I hate C so much... */
 
 

+/* Used when printing error/debugging messages from signal handlers.
+ */
+static const char *
+no_malloc_number_to_string (long num)
+{
+  static char string[128] = "";
+  int num_digits;
+  Bool negative_p = False;
+
+  num_digits = 0;
+
+  if (num == 0)
+    return "0";
+
+  if (num < 0)
+    {
+      negative_p = True;
+      num = -num;
+    }
+
+  while ((num > 0) && (num_digits < sizeof(string - 1)))
+    {
+      int digit;
+      digit = (int) num % 10;
+      num_digits++;
+      string[sizeof(string) - 1 - num_digits] = digit + '0';
+      num /= 10;
+    }
+
+  if (negative_p)
+    {
+      num_digits++;
+      string[sizeof(string) - 1 - num_digits] = '-';
+    }
+
+  return string + sizeof(string) - 1 - num_digits;
+}
+
+/* Like write(), but runs strlen() on the arg to get the length. */
+static int
+write_string (int fd, const char *str)
+{
+  return write (fd, str, strlen (str));
+}
+
+static int
+write_long (int fd, long n)
+{
+  const char *str = no_malloc_number_to_string (n);
+  return write_string (fd, str);
+}
+
+

 /* RLIMIT_AS (called RLIMIT_VMEM on some systems) controls the maximum size
    of a process's address space, i.e., the maximal brk(2) and mmap(2) values.
    Setting this lets you put a cap on how much memory a process can allocate.
 /* RLIMIT_AS (called RLIMIT_VMEM on some systems) controls the maximum size
    of a process's address space, i.e., the maximal brk(2) and mmap(2) values.
    Setting this lets you put a cap on how much memory a process can allocate.


@@ -88,6 +143,12 @@ extern saver_info *global_si_kludge;        /* I hate C so much... */
 static void
 limit_subproc_memory (int address_space_limit, Bool verbose_p)
 {
 static void
 limit_subproc_memory (int address_space_limit, Bool verbose_p)
 {

+
+/* This has caused way more problems than it has solved...
+   Let's just completely ignore the "memoryLimit" option now.
+ */
+#undef HAVE_SETRLIMIT
+

 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_AS)
   struct rlimit r;
 
 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_AS)
   struct rlimit r;
 


@@ -157,7 +218,10 @@ struct screenhack_job {
 
 static struct screenhack_job *jobs = 0;
 
 
 static struct screenhack_job *jobs = 0;
 

-/* for debugging -- nothing calls this, but it's useful to invoke from gdb. */
+/* for debugging -- nothing calls this, but it's useful to invoke from gdb.
+ */
+void show_job_list (void);
+

 void
 show_job_list (void)
 {
 void
 show_job_list (void)
 {


@@ -288,17 +352,28 @@ static void describe_dead_child (saver_info *, pid_t, int wait_status);
 static int block_sigchld_handler = 0;
 
 
 static int block_sigchld_handler = 0;
 
 

-void
+#ifdef HAVE_SIGACTION
+ sigset_t
+#else  /* !HAVE_SIGACTION */
+ int
+#endif /* !HAVE_SIGACTION */

 block_sigchld (void)
 {
 #ifdef HAVE_SIGACTION
   sigset_t child_set;
   sigemptyset (&child_set);
   sigaddset (&child_set, SIGCHLD);
 block_sigchld (void)
 {
 #ifdef HAVE_SIGACTION
   sigset_t child_set;
   sigemptyset (&child_set);
   sigaddset (&child_set, SIGCHLD);

+  sigaddset (&child_set, SIGPIPE);

   sigprocmask (SIG_BLOCK, &child_set, 0);
 #endif /* HAVE_SIGACTION */
 
   block_sigchld_handler++;
   sigprocmask (SIG_BLOCK, &child_set, 0);
 #endif /* HAVE_SIGACTION */
 
   block_sigchld_handler++;

+
+#ifdef HAVE_SIGACTION
+  return child_set;
+#else  /* !HAVE_SIGACTION */
+  return 0;
+#endif /* !HAVE_SIGACTION */

 }
 
 void
 }
 
 void


@@ -308,6 +383,7 @@ unblock_sigchld (void)
   sigset_t child_set;
   sigemptyset(&child_set);
   sigaddset(&child_set, SIGCHLD);
   sigset_t child_set;
   sigemptyset(&child_set);
   sigaddset(&child_set, SIGCHLD);

+  sigaddset(&child_set, SIGPIPE);

   sigprocmask(SIG_UNBLOCK, &child_set, 0);
 #endif /* HAVE_SIGACTION */
 
   sigprocmask(SIG_UNBLOCK, &child_set, 0);
 #endif /* HAVE_SIGACTION */
 


@@ -394,8 +470,19 @@ sigchld_handler (int sig)
   saver_info *si = global_si_kludge;   /* I hate C so much... */
 
   if (si->prefs.debug_p)
   saver_info *si = global_si_kludge;   /* I hate C so much... */
 
   if (si->prefs.debug_p)

-    fprintf(stderr, "%s: got SIGCHLD%s\n", blurb(),
+    {
+      /* Don't call fprintf() from signal handlers, as it might malloc.
+      fprintf(stderr, "%s: got SIGCHLD%s\n", blurb(),

            (block_sigchld_handler ? " (blocked)" : ""));
            (block_sigchld_handler ? " (blocked)" : ""));

+      */
+      write_string (STDERR_FILENO, blurb());
+      write_string (STDERR_FILENO, ": got SIGCHLD");
+
+      if (block_sigchld_handler)
+        write_string (STDERR_FILENO, " (blocked)\n");
+      else
+        write_string (STDERR_FILENO, "\n");
+    }

 
   if (block_sigchld_handler < 0)
     abort();
 
   if (block_sigchld_handler < 0)
     abort();


@@ -412,6 +499,7 @@ sigchld_handler (int sig)
 
 
 #ifndef VMS
 
 
 #ifndef VMS

+

 static void
 await_dying_children (saver_info *si)
 {
 static void
 await_dying_children (saver_info *si)
 {


@@ -426,11 +514,29 @@ await_dying_children (saver_info *si)
       if (si->prefs.debug_p)
        {
          if (kid < 0 && errno)
       if (si->prefs.debug_p)
        {
          if (kid < 0 && errno)

-           fprintf (stderr, "%s: waitpid(-1) ==> %ld (%d)\n", blurb(),
-                    (long) kid, errno);
-         else
-           fprintf (stderr, "%s: waitpid(-1) ==> %ld\n", blurb(),
-                    (long) kid);
+            {
+              /* Don't call fprintf() from signal handlers, as it might malloc.
+             fprintf (stderr, "%s: waitpid(-1) ==> %ld (%d)\n", blurb(),
+                      (long) kid, errno);
+               */
+              write_string (STDERR_FILENO, blurb());
+              write_string (STDERR_FILENO, ": waitpid(-1) ==> ");
+              write_long   (STDERR_FILENO, (long) kid);
+              write_string (STDERR_FILENO, " (");
+              write_long   (STDERR_FILENO, (long) errno);
+              write_string (STDERR_FILENO, ")\n");
+            }
+          else
+            {
+              /* Don't call fprintf() from signal handlers, as it might malloc.
+              fprintf (stderr, "%s: waitpid(-1) ==> %ld\n", blurb(),
+                       (long) kid);
+               */
+              write_string (STDERR_FILENO, blurb());
+              write_string (STDERR_FILENO, ": waitpid(-1) ==> ");
+              write_long   (STDERR_FILENO, (long) kid);
+              write_string (STDERR_FILENO, "\n");
+            }

        }
 
       /* 0 means no more children to reap.
        }
 
       /* 0 means no more children to reap.


@@ -470,12 +576,38 @@ describe_dead_child (saver_info *si, pid_t kid, int wait_status)
       if (!job ||
          (exit_status != 0 &&
           (p->verbose_p || job->status != job_killed)))
       if (!job ||
          (exit_status != 0 &&
           (p->verbose_p || job->status != job_killed)))

-       fprintf (stderr,
-                "%s: %d: child pid %lu (%s) exited abnormally (code %d).\n",
-                blurb(), screen_no, (unsigned long) kid, name, exit_status);
+        {
+          /* Don't call fprintf() from signal handlers, as it might malloc.
+         fprintf (stderr,
+                  "%s: %d: child pid %lu (%s) exited abnormally (code %d).\n",
+                  blurb(), screen_no, (unsigned long) kid, name, exit_status);
+           */
+          write_string (STDERR_FILENO, blurb());
+          write_string (STDERR_FILENO, ": ");
+          write_long   (STDERR_FILENO, (long) screen_no);
+          write_string (STDERR_FILENO, ": child pid ");
+          write_long   (STDERR_FILENO, (long) kid);
+          write_string (STDERR_FILENO, " (");
+          write_string (STDERR_FILENO, name);
+          write_string (STDERR_FILENO, ") exited abnormally (code ");
+          write_long   (STDERR_FILENO, (long) exit_status);
+          write_string (STDERR_FILENO, ").\n"); 
+        }

       else if (p->verbose_p)
       else if (p->verbose_p)

-       fprintf (stderr, "%s: %d: child pid %lu (%s) exited normally.\n",
-                blurb(), screen_no, (unsigned long) kid, name);
+        {
+          /* Don't call fprintf() from signal handlers, as it might malloc.
+         fprintf (stderr, "%s: %d: child pid %lu (%s) exited normally.\n",
+                  blurb(), screen_no, (unsigned long) kid, name);
+           */
+          write_string (STDERR_FILENO, blurb());
+          write_string (STDERR_FILENO, ": ");
+          write_long   (STDERR_FILENO, (long) screen_no);
+          write_string (STDERR_FILENO, ": child pid ");
+          write_long   (STDERR_FILENO, (long) kid);
+          write_string (STDERR_FILENO, " (");
+          write_string (STDERR_FILENO, name);
+          write_string (STDERR_FILENO, ") exited normally.\n");
+        }

 
       if (job)
        job->status = job_dead;
 
       if (job)
        job->status = job_dead;


@@ -486,9 +618,23 @@ describe_dead_child (saver_info *si, pid_t kid, int wait_status)
          !job ||
          job->status != job_killed ||
          WTERMSIG (wait_status) != SIGTERM)
          !job ||
          job->status != job_killed ||
          WTERMSIG (wait_status) != SIGTERM)

-       fprintf (stderr, "%s: %d: child pid %lu (%s) terminated with %s.\n",
-                blurb(), screen_no, (unsigned long) kid, name,
-                signal_name (WTERMSIG(wait_status)));
+        {
+          /* Don't call fprintf() from signal handlers, as it might malloc.
+         fprintf (stderr, "%s: %d: child pid %lu (%s) terminated with %s.\n",
+                  blurb(), screen_no, (unsigned long) kid, name,
+                  signal_name (WTERMSIG(wait_status)));
+           */
+          write_string (STDERR_FILENO, blurb());
+          write_string (STDERR_FILENO, ": ");
+          write_long   (STDERR_FILENO, (long) screen_no);
+          write_string (STDERR_FILENO, ": child pid ");
+          write_long   (STDERR_FILENO, (long) kid);
+          write_string (STDERR_FILENO, " (");
+          write_string (STDERR_FILENO, name);
+          write_string (STDERR_FILENO, ") terminated with signal ");
+          write_long   (STDERR_FILENO, WTERMSIG(wait_status));
+          write_string (STDERR_FILENO, ".\n");
+        }

 
       if (job)
        job->status = job_dead;
 
       if (job)
        job->status = job_dead;


@@ -496,17 +642,41 @@ describe_dead_child (saver_info *si, pid_t kid, int wait_status)
   else if (WIFSTOPPED (wait_status))
     {
       if (p->verbose_p)
   else if (WIFSTOPPED (wait_status))
     {
       if (p->verbose_p)

-       fprintf (stderr, "%s: child pid %lu (%s) stopped with %s.\n",
-                blurb(), (unsigned long) kid, name,
-                signal_name (WSTOPSIG (wait_status)));
+        {
+          /* Don't call fprintf() from signal handlers, as it might malloc.
+         fprintf (stderr, "%s: child pid %lu (%s) stopped with %s.\n",
+                  blurb(), (unsigned long) kid, name,
+                  signal_name (WSTOPSIG (wait_status)));
+           */
+          write_string (STDERR_FILENO, blurb());
+          write_string (STDERR_FILENO, ": ");
+          write_long   (STDERR_FILENO, (long) screen_no);
+          write_string (STDERR_FILENO, ": child pid ");
+          write_long   (STDERR_FILENO, (long) kid);
+          write_string (STDERR_FILENO, " (");
+          write_string (STDERR_FILENO, name);
+          write_string (STDERR_FILENO, ") stopped with signal ");
+          write_long   (STDERR_FILENO, WSTOPSIG(wait_status));
+          write_string (STDERR_FILENO, ".\n");
+        }

 
       if (job)
        job->status = job_stopped;
     }
   else
     {
 
       if (job)
        job->status = job_stopped;
     }
   else
     {

+      /* Don't call fprintf() from signal handlers, as it might malloc.

       fprintf (stderr, "%s: child pid %lu (%s) died in a mysterious way!",
               blurb(), (unsigned long) kid, name);
       fprintf (stderr, "%s: child pid %lu (%s) died in a mysterious way!",
               blurb(), (unsigned long) kid, name);

+       */
+      write_string (STDERR_FILENO, blurb());
+      write_string (STDERR_FILENO, ": ");
+      write_long   (STDERR_FILENO, (long) screen_no);
+      write_string (STDERR_FILENO, ": child pid ");
+      write_long   (STDERR_FILENO, (long) kid);
+      write_string (STDERR_FILENO, " (");
+      write_string (STDERR_FILENO, name);
+      write_string (STDERR_FILENO, ") died in a mysterious way!");

       if (job)
        job->status = job_dead;
     }
       if (job)
        job->status = job_dead;
     }


@@ -619,7 +789,8 @@ print_path_error (const char *program)
       fprintf (stderr, "\n");
       *path = 0;
 # if defined(HAVE_GETCWD)
       fprintf (stderr, "\n");
       *path = 0;
 # if defined(HAVE_GETCWD)

-      getcwd (path, sizeof(path));
+      if (! getcwd (path, sizeof(path)))
+        *path = 0;

 # elif defined(HAVE_GETWD)
       getwd (path);
 # endif
 # elif defined(HAVE_GETWD)
       getwd (path);
 # endif


@@ -637,6 +808,60 @@ print_path_error (const char *program)
 }
 
 
 }
 
 

+/* Executes the command in another process.
+   Command may be any single command acceptable to /bin/sh.
+   It may include wildcards, but no semicolons.
+   If successful, the pid of the other process is returned.
+   Otherwise, -1 is returned and an error may have been
+   printed to stderr.
+ */
+pid_t
+fork_and_exec (saver_screen_info *ssi, const char *command)
+{
+  saver_info *si = ssi->global;
+  saver_preferences *p = &si->prefs;
+  pid_t forked;
+
+  switch ((int) (forked = fork ()))
+    {
+    case -1:
+      {
+        char buf [255];
+        sprintf (buf, "%s: couldn't fork", blurb());
+        perror (buf);
+        break;
+      }
+
+    case 0:
+      close (ConnectionNumber (si->dpy));      /* close display fd */
+      limit_subproc_memory (p->inferior_memory_limit, p->verbose_p);
+      hack_subproc_environment (ssi);          /* set $DISPLAY */
+
+      if (p->verbose_p)
+        fprintf (stderr, "%s: %d: spawning \"%s\" in pid %lu.\n",
+                 blurb(), ssi->number, command,
+                 (unsigned long) getpid ());
+
+      exec_command (p->shell, command, p->nice_inferior);
+
+      /* If that returned, we were unable to exec the subprocess.
+         Print an error message, if desired.
+       */
+      if (! p->ignore_uninstalled_p)
+        print_path_error (command);
+
+      exit (1);  /* exits child fork */
+      break;
+
+    default:   /* parent */
+      (void) make_job (forked, ssi->number, command);
+      break;
+    }
+
+  return forked;
+}
+
+

 static void
 spawn_screenhack_1 (saver_screen_info *ssi, Bool first_time_p)
 {
 static void
 spawn_screenhack_1 (saver_screen_info *ssi, Bool first_time_p)
 {


@@ -650,7 +875,7 @@ spawn_screenhack_1 (saver_screen_info *ssi, Bool first_time_p)
       screenhack *hack;
       pid_t forked;
       char buf [255];
       screenhack *hack;
       pid_t forked;
       char buf [255];

-      int new_hack;
+      int new_hack = -1;

       int retry_count = 0;
       Bool force = False;
 
       int retry_count = 0;
       Bool force = False;
 


@@ -697,6 +922,14 @@ spawn_screenhack_1 (saver_screen_info *ssi, Bool first_time_p)
         {
           new_hack = -1;
         }
         {
           new_hack = -1;
         }

+      else if (p->mode == RANDOM_HACKS_SAME &&
+               ssi->number != 0)
+       {
+         /* Use the same hack that's running on screen 0.
+             (Assumes this function was called on screen 0 first.)
+           */
+          new_hack = si->screens[0].current_hack;
+       }

       else  /* (p->mode == RANDOM_HACKS) */
        {
          /* Select a random hack (but not the one we just ran.) */
       else  /* (p->mode == RANDOM_HACKS) */
        {
          /* Select a random hack (but not the one we just ran.) */


@@ -726,6 +959,7 @@ spawn_screenhack_1 (saver_screen_info *ssi, Bool first_time_p)
         
       if (!force &&
          (!hack->enabled_p ||
         
       if (!force &&
          (!hack->enabled_p ||

+          !on_path_p (hack->command) ||

           !select_visual_of_hack (ssi, hack)))
        {
          if (++retry_count > (p->screenhacks_count*4))
           !select_visual_of_hack (ssi, hack)))
        {
          if (++retry_count > (p->screenhacks_count*4))


@@ -751,38 +985,19 @@ spawn_screenhack_1 (saver_screen_info *ssi, Bool first_time_p)
       if (si->selection_mode < 0)
        si->selection_mode = 0;
 
       if (si->selection_mode < 0)
        si->selection_mode = 0;
 

-      switch ((int) (forked = fork ()))
+      forked = fork_and_exec (ssi, hack->command);
+      switch ((int) forked)

        {
        {

-       case -1:
+       case -1: /* fork failed */
+       case 0:  /* child fork (can't happen) */

          sprintf (buf, "%s: couldn't fork", blurb());
          perror (buf);
          restore_real_vroot (si);
          sprintf (buf, "%s: couldn't fork", blurb());
          perror (buf);
          restore_real_vroot (si);

-         saver_exit (si, 1, 0);
-
-       case 0:
-         close (ConnectionNumber (si->dpy));   /* close display fd */
-         limit_subproc_memory (p->inferior_memory_limit, p->verbose_p);
-         hack_subproc_environment (ssi);       /* set $DISPLAY */
-
-          if (p->verbose_p)
-            fprintf (stderr, "%s: %d: spawning \"%s\" in pid %lu.\n",
-                     blurb(), ssi->number, hack->command,
-                     (unsigned long) getpid ());
-
-         exec_command (p->shell, hack->command, p->nice_inferior);
-
-          /* If that returned, we were unable to exec the subprocess.
-             Print an error message, if desired.
-           */
-          if (! p->ignore_uninstalled_p)
-            print_path_error (hack->command);
-
-          exit (1);  /* exits child fork */
+         saver_exit (si, 1, "couldn't fork");

          break;
 
        default:
          ssi->pid = forked;
          break;
 
        default:
          ssi->pid = forked;

-         (void) make_job (forked, ssi->number, hack->command);

          break;
        }
     }
          break;
        }
     }


@@ -916,29 +1131,46 @@ hack_subproc_environment (saver_screen_info *ssi)
      be the screen on which this particular hack is running -- not the display
      specification which the driver itself is using, since the driver ignores
      its screen number and manages all existing screens.
      be the screen on which this particular hack is running -- not the display
      specification which the driver itself is using, since the driver ignores
      its screen number and manages all existing screens.

+
+     Likewise, store a window ID in $XSCREENSAVER_WINDOW -- this will allow
+     us to (eventually) run multiple hacks in Xinerama mode, where each hack
+     has the same $DISPLAY but a different piece of glass.

    */
   saver_info *si = ssi->global;
   const char *odpy = DisplayString (si->dpy);
    */
   saver_info *si = ssi->global;
   const char *odpy = DisplayString (si->dpy);

-  char *ndpy = (char *) malloc(strlen(odpy) + 20);
-  char *s;
+  char *ndpy = (char *) malloc (strlen(odpy) + 20);
+  char *nssw = (char *) malloc (40);
+  char *s, *c;

 
   strcpy (ndpy, "DISPLAY=");
   s = ndpy + strlen(ndpy);
   strcpy (s, odpy);
 
 
   strcpy (ndpy, "DISPLAY=");
   s = ndpy + strlen(ndpy);
   strcpy (s, odpy);
 

-  while (*s && *s != ':') s++;                 /* skip to colon */
-  while (*s == ':') s++;                       /* skip over colons */
+  /* We have to find the last colon since it is the boundary between
+     hostname & screen - IPv6 numeric format addresses may have many
+     colons before that point, and DECnet addresses always have two colons */
+  c = strrchr(s,':');                          /* skip to last colon */
+  if (c != NULL) s = c+1;

   while (isdigit(*s)) s++;                     /* skip over dpy number */
   while (*s == '.') s++;                       /* skip over dot */
   if (s[-1] != '.') *s++ = '.';                        /* put on a dot */
   while (isdigit(*s)) s++;                     /* skip over dpy number */
   while (*s == '.') s++;                       /* skip over dot */
   if (s[-1] != '.') *s++ = '.';                        /* put on a dot */

-  sprintf(s, "%d", ssi->number);               /* put on screen number */
+  sprintf(s, "%d", ssi->real_screen_number);   /* put on screen number */
+
+  sprintf (nssw, "XSCREENSAVER_WINDOW=0x%lX",
+           (unsigned long) ssi->screensaver_window);

 
   /* Allegedly, BSD 4.3 didn't have putenv(), but nobody runs such systems
      any more, right?  It's not Posix, but everyone seems to have it. */
 #ifdef HAVE_PUTENV
   if (putenv (ndpy))
     abort ();
 
   /* Allegedly, BSD 4.3 didn't have putenv(), but nobody runs such systems
      any more, right?  It's not Posix, but everyone seems to have it. */
 #ifdef HAVE_PUTENV
   if (putenv (ndpy))
     abort ();

-  /* do not free(ndpy) -- see above. */
+  if (putenv (nssw))
+    abort ();
+
+  /* don't free ndpy/nssw -- some implementations of putenv (BSD 4.4,
+     glibc 2.0) copy the argument, but some (libc4,5, glibc 2.1.2)
+     do not.  So we must leak it (and/or the previous setting). Yay.
+   */

 #endif /* HAVE_PUTENV */
 }
 
 #endif /* HAVE_PUTENV */
 }
 


@@ -1015,7 +1247,8 @@ get_best_gl_visual (saver_screen_info *ssi)
         close (out);  /* don't need this one */
 
         *buf = 0;
         close (out);  /* don't need this one */
 
         *buf = 0;

-        fgets (buf, sizeof(buf)-1, f);
+        if (! fgets (buf, sizeof(buf)-1, f))
+          *buf = 0;

         fclose (f);
 
         /* Wait for the child to die. */
         fclose (f);
 
         /* Wait for the child to die. */