/* subprocs.c --- choosing, spawning, and killing screenhacks.
* xscreensaver, Copyright (c) 1991, 1992, 1993, 1995, 1997, 1998
- * Jamie Zawinski <jwz@netscape.com>
+ * 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
#include <X11/Xlib.h> /* not used for much... */
#ifndef ESRCH
-#include <errno.h>
+# include <errno.h>
#endif
#include <sys/time.h> /* sys/resource.h needs this for timeval */
-#ifndef VMS
-
-# include <sys/resource.h> /* for setpriority() and PRIO_PROCESS */
+#ifdef HAVE_SYS_WAIT_H
# include <sys/wait.h> /* for waitpid() and associated macros */
+#endif
-#else /* VMS */
-
-# if __DECC_VER >= 50200000
-# include <sys/wait.h>
-# endif
+#if defined(HAVE_SETPRIORITY) && defined(PRIO_PROCESS)
+# include <sys/resource.h> /* for setpriority() and PRIO_PROCESS */
+#endif
+#ifdef VMS
# include <processes.h>
# include <unixio.h> /* for close */
# include <unixlib.h> /* for getpid */
-# define pid_t int
-# define fork vfork
-
+# define pid_t int
+# define fork vfork
#endif /* VMS */
#include <signal.h> /* for the signal names */
-#ifndef NO_SETUID
-#include <pwd.h> /* for getpwnam() and struct passwd */
-#include <grp.h> /* for getgrgid() and struct group */
-#endif /* NO_SETUID */
-
#if !defined(SIGCHLD) && defined(SIGCLD)
-#define SIGCHLD SIGCLD
+# define SIGCHLD SIGCLD
#endif
+#if 0 /* putenv() is declared in stdlib.h on modern linux systems. */
#ifdef HAVE_PUTENV
extern int putenv (/* const char * */); /* getenv() is in stdlib.h... */
#endif
+#endif
+
extern int kill (pid_t, int); /* signal() is in sys/signal.h... */
/* This file doesn't need the Xt headers, so stub these types out... */
Bool hairy_p = !!strpbrk (command, "*?$&!<>[];`'\\\"");
if (p->verbose_p)
- printf ("%s: spawning \"%s\" in pid %lu%s.\n",
- blurb(), command, (unsigned long) getpid (),
- (hairy_p ? " (via shell)" : ""));
+ fprintf (stderr, "%s: spawning \"%s\" in pid %lu%s.\n",
+ blurb(), command, (unsigned long) getpid (),
+ (hairy_p ? " (via shell)" : ""));
if (hairy_p)
/* If it contains any shell metacharacters, do it the hard way,
#else /* VMS */
if (p->verbose_p)
- printf ("%s: spawning \"%s\" in pid %lu.\n", blurb(), command, getpid());
+ fprintf (stderr, "%s: spawning \"%s\" in pid %lu.\n",
+ blurb(), command, getpid());
exec_vms_command (command);
#endif /* VMS */
"%s: child pid %lu (%s) exited abnormally (code %d).\n",
blurb(), (unsigned long) kid, name, exit_status);
else if (p->verbose_p)
- printf ("%s: child pid %lu (%s) exited normally.\n",
- blurb(), (unsigned long) kid, name);
+ fprintf (stderr, "%s: child pid %lu (%s) exited normally.\n",
+ blurb(), (unsigned long) kid, name);
if (job)
job->status = job_dead;
AGAIN:
if (p->screenhacks_count == 1)
new_hack = 0;
- else if (si->next_mode_p == 1)
+ else if (si->selection_mode == -1)
new_hack = (ssi->current_hack + 1) % p->screenhacks_count;
- else if (si->next_mode_p == 2)
+ else if (si->selection_mode == -2)
new_hack = ((ssi->current_hack + p->screenhacks_count - 1)
% p->screenhacks_count);
+ else if (si->selection_mode > 0)
+ new_hack = ((si->selection_mode - 1) % p->screenhacks_count);
else
while ((new_hack = random () % p->screenhacks_count)
== ssi->current_hack)
goto AGAIN;
}
}
- si->next_mode_p = 0;
+
+ if (si->selection_mode < 0)
+ si->selection_mode = 0;
/* If there's a visual description on the front of the command, nuke it.
sprintf (buf, "%s: couldn't fork", blurb());
perror (buf);
restore_real_vroot (si);
- saver_exit (si, 1);
+ saver_exit (si, 1, 0);
case 0:
close (ConnectionNumber (si->dpy)); /* close display fd */
if (!monitor_powered_on_p (si))
{
if (si->prefs.verbose_p)
- printf ("%s: server reports that monitor has powered down; "
- "not launching a new hack.\n", blurb());
+ fprintf (stderr,
+ "%s: server reports that monitor has powered down; "
+ "not launching a new hack.\n", blurb());
return;
}
}
\f
-/* Restarting the xscreensaver process from scratch. */
+/* Environment variables. */
-static char **saved_argv;
+/* Modifies $PATH in the current environment, so that if DEFAULT_PATH_PREFIX
+ is defined, the xscreensaver daemon will search that directory for hacks.
+ */
void
-save_argv (int argc, char **argv)
+hack_environment (saver_info *si)
{
- saved_argv = (char **) malloc ((argc + 2) * sizeof (char *));
- saved_argv [argc] = 0;
- while (argc--)
+#if defined(HAVE_PUTENV) && defined(DEFAULT_PATH_PREFIX)
+ static const char *def_path = DEFAULT_PATH_PREFIX;
+ if (def_path && *def_path)
{
- int i = strlen (argv [argc]) + 1;
- saved_argv [argc] = (char *) malloc (i);
- memcpy (saved_argv [argc], argv [argc], i);
- }
-}
+ const char *opath = getenv("PATH");
+ char *npath = (char *) malloc(strlen(def_path) + strlen(opath) + 20);
+ strcpy (npath, "PATH=");
+ strcat (npath, def_path);
+ strcat (npath, ":");
+ strcat (npath, opath);
-void
-restart_process (saver_info *si)
-{
- fflush (real_stdout);
- fflush (real_stderr);
- execvp (saved_argv [0], saved_argv); /* shouldn't return */
- {
- char buf [512];
- sprintf (buf, "%s: could not restart process", blurb());
- perror(buf);
- fflush(stderr);
- }
+ if (putenv (npath))
+ abort ();
+ }
+#endif /* HAVE_PUTENV && DEFAULT_PATH_PREFIX */
}
-/* Like restart_process(), but ensures that when it restarts,
- it comes up in demo-mode. */
-void
-demo_mode_restart_process (saver_info *si)
-{
- int i;
- for (i = 0; saved_argv [i]; i++);
- /* add the -initial-demo-mode switch; save_argv() left room for this. */
- saved_argv [i] = "-initial-demo-mode";
- saved_argv [i+1] = 0;
- restart_process (si); /* shouldn't return */
- saved_argv [i] = 0;
- XBell(si->dpy, 0);
-}
static void
hack_subproc_environment (saver_screen_info *ssi)
for (screen_number = 0; screen_number < si->nscreens; screen_number++)
if (ssi == &si->screens[screen_number])
break;
- if (screen_number >= si->nscreens) abort();
strcpy (ndpy, "DISPLAY=");
s = ndpy + strlen(ndpy);
#endif /* HAVE_PUTENV */
}
+\f
+/* Restarting the xscreensaver process from scratch. */
+
+static char **saved_argv;
void
-hack_environment (saver_info *si)
+save_argv (int argc, char **argv)
{
-#if defined(HAVE_PUTENV) && defined(DEFAULT_PATH_PREFIX)
- static const char *def_path = DEFAULT_PATH_PREFIX;
- if (def_path && *def_path)
+ /* Leave room for one more argument, the -initial-demo-mode switch. */
+ saved_argv = (char **) calloc (argc+2, sizeof (char *));
+ saved_argv [argc] = 0;
+ while (argc--)
{
- const char *opath = getenv("PATH");
- char *npath = (char *) malloc(strlen(def_path) + strlen(opath) + 20);
- strcpy (npath, "PATH=");
- strcat (npath, def_path);
- strcat (npath, ":");
- strcat (npath, opath);
-
- if (putenv (npath))
- abort ();
+ int i = strlen (argv [argc]) + 1;
+ saved_argv [argc] = (char *) malloc (i);
+ memcpy (saved_argv [argc], argv [argc], i);
}
-#endif /* HAVE_PUTENV && DEFAULT_PATH_PREFIX */
}
-
-\f
-/* Change the uid/gid of the screensaver process, so that it is safe for it
- to run setuid root (which it needs to do on some systems to read the
- encrypted passwords from the passwd file.)
-
- hack_uid() is run before opening the X connection, so that XAuth works.
- hack_uid_warn() is called after the connection is opened and the command
- line arguments are parsed, so that the messages from hack_uid() get
- printed after we know whether we're in `verbose' mode.
+/* Modifies saved_argv to either contain or not contain "-initial-demo-mode".
*/
+static void
+hack_saved_argv (Bool demo_mode_p)
+{
+ static char *demo_mode_switch = "-initial-demo-mode";
-#ifndef NO_SETUID
+ if (demo_mode_p) /* We want the switch to be in the args. */
+ {
+ /* See if the switch is there already. If so, we're done. */
+ int i;
+ for (i = 0; saved_argv[i]; i++)
+ if (!strcmp (saved_argv[i], demo_mode_switch))
+ return;
+
+ /* If it wasn't there, add it to the end. save_argv() made room. */
+ saved_argv [i] = demo_mode_switch;
+ saved_argv [i+1] = 0;
+ }
+ else /* We want the switch to not be in the args. */
+ {
+ int i;
+ for (i = 0; saved_argv[i]; i++)
+ while (!strcmp (saved_argv [i], demo_mode_switch))
+ {
+ int j;
+ for (j = i; saved_argv[j]; j++)
+ saved_argv [j] = saved_argv [j+1];
+ }
+ }
+}
-static int hack_uid_errno;
-static char hack_uid_buf [255], *hack_uid_error;
-void
-hack_uid (saver_info *si)
+/* Re-execs the process with the arguments in saved_argv.
+ Does not return unless there was an error.
+ */
+static void
+restart_process_1 (saver_info *si)
{
+ fflush (real_stdout);
+ fflush (real_stderr);
+ execvp (saved_argv [0], saved_argv); /* shouldn't return */
+ {
+ char buf [512];
+ sprintf (buf, "%s: could not restart process", blurb());
+ perror(buf);
+ fflush(stderr);
+ }
+ XBell(si->dpy, 0);
+}
- /* If we've been run as setuid or setgid to someone else (most likely root)
- turn off the extra permissions so that random user-specified programs
- don't get special privileges. (On some systems it might be necessary
- to install this as setuid root in order to read the passwd file to
- implement lock-mode...)
- */
- setgid (getgid ());
- setuid (getuid ());
-
- hack_uid_errno = 0;
- hack_uid_error = 0;
-
- /* If we're being run as root (as from xdm) then switch the user id
- to something safe. */
- if (getuid () == 0)
- {
- struct passwd *p;
- /* Locking can't work when running as root, because we have no way of
- knowing what the user id of the logged in user is (so we don't know
- whose password to prompt for.)
- */
- si->locking_disabled_p = True;
- si->nolock_reason = "running as root";
- p = getpwnam ("nobody");
- if (! p) p = getpwnam ("noaccess");
- if (! p) p = getpwnam ("daemon");
- if (! p) p = getpwnam ("bin");
- if (! p) p = getpwnam ("sys");
- if (! p)
- {
- hack_uid_error = "couldn't find safe uid; running as root.";
- hack_uid_errno = -1;
- }
- else
- {
- struct group *g = getgrgid (p->pw_gid);
- hack_uid_error = hack_uid_buf;
- sprintf (hack_uid_error, "changing uid/gid to %s/%s (%ld/%ld).",
- p->pw_name, (g ? g->gr_name : "???"),
- (long) p->pw_uid, (long) p->pw_gid);
-
- /* Change the gid to be a safe one. If we can't do that, then
- print a warning. We change the gid before the uid so that we
- change the gid while still root. */
- if (setgid (p->pw_gid) != 0)
- {
- hack_uid_errno = errno;
- sprintf (hack_uid_error, "couldn't set gid to %s (%ld)",
- (g ? g->gr_name : "???"), (long) p->pw_gid);
- }
- /* Now change the uid to be a safe one. */
- if (setuid (p->pw_uid) != 0)
- {
- hack_uid_errno = errno;
- sprintf (hack_uid_error, "couldn't set uid to %s (%ld)",
- p->pw_name, (long) p->pw_uid);
- }
- }
- }
-# ifndef NO_LOCKING
- else /* disable locking if already being run as "someone else" */
- {
- struct passwd *p = getpwuid (getuid ());
- if (!p ||
- !strcmp (p->pw_name, "root") ||
- !strcmp (p->pw_name, "nobody") ||
- !strcmp (p->pw_name, "noaccess") ||
- !strcmp (p->pw_name, "daemon") ||
- !strcmp (p->pw_name, "bin") ||
- !strcmp (p->pw_name, "sys"))
- {
- si->locking_disabled_p = True;
- si->nolock_reason = hack_uid_buf;
- sprintf (si->nolock_reason, "running as %s", p->pw_name);
- }
- }
-# endif /* !NO_LOCKING */
+/* Re-execs the process with the arguments in saved_argv,
+ minus -initial-demo-mode.
+ Does not return unless there was an error.
+ */
+void
+restart_process (saver_info *si)
+{
+ hack_saved_argv (True);
+ restart_process_1 (si);
}
+/* Re-execs the process with the arguments in saved_argv,
+ plus -initial-demo-mode.
+ Does not return unless there was an error.
+ */
void
-hack_uid_warn (saver_info *si)
+demo_mode_restart_process (saver_info *si)
{
- saver_preferences *p = &si->prefs;
-
- if (! hack_uid_error)
- ;
- else if (hack_uid_errno == 0)
- {
- if (p->verbose_p)
- printf ("%s: %s\n", blurb(), hack_uid_error);
- }
- else
- {
- char buf [255];
- sprintf (buf, "%s: %s", blurb(), hack_uid_error);
- if (hack_uid_errno == -1)
- fprintf (stderr, "%s\n", buf);
- else
- {
- errno = hack_uid_errno;
- perror (buf);
- }
- }
+ hack_saved_argv (False);
+ restart_process_1 (si);
}
-
-#endif /* !NO_SETUID */
projects / xscreensaver / blobdiff