Run the editor in its own process group.

This fixes suspending the editor on GNU Hurd which doesn't seem to
have proper process group signal handling.

MANIFEST

@@ -360,6 +360,7 @@ lib/util/strtonum.c
 lib/util/sudo_conf.c
 lib/util/sudo_debug.c
 lib/util/sudo_dso.c
+lib/util/suspend_parent.c
 lib/util/sys_siglist.h
 lib/util/sys_signame.h
 lib/util/term.c
@@ -599,6 +600,7 @@ plugins/sudoers/b64_encode.c
 plugins/sudoers/boottime.c
 plugins/sudoers/bsm_audit.c
 plugins/sudoers/bsm_audit.h
+plugins/sudoers/canon_path.c
 plugins/sudoers/check.c
 plugins/sudoers/check.h
 plugins/sudoers/check_aliases.c
@@ -740,7 +742,6 @@ plugins/sudoers/prompt.c
 plugins/sudoers/pwutil.c
 plugins/sudoers/pwutil.h
 plugins/sudoers/pwutil_impl.c
-plugins/sudoers/canon_path.c
 plugins/sudoers/redblack.c
 plugins/sudoers/redblack.h
 plugins/sudoers/regress/check_symbols/check_symbols.c
@@ -1269,8 +1270,6 @@ src/sudo_intercept_common.c
 src/sudo_noexec.c
 src/sudo_plugin_int.h
 src/sudo_usage.h.in
-src/suspend_nopty.c
-src/tcsetpgrp_nobg.c
 src/tgetpass.c
 src/ttyname.c
 src/utmp.c

include/sudo_util.h

@@ -344,6 +344,10 @@ sudo_dso_public int sudo_strtomode_v1(const char *cp, const char **errstr);
 /* sudo_printf.c */
 extern int (*sudo_printf)(int msg_type, const char *fmt, ...);
 
+/* suspend_parent.c */
+sudo_dso_public void sudo_suspend_parent_v1(int signo, pid_t my_pid, pid_t my_pgrp, pid_t cmnd_pid, void *closure, void (*callback)(void *, int));
+#define sudo_suspend_parent(_a, _b, _c, _d, _e, _f) sudo_suspend_parent_v1((_a), (_b), (_c), (_d), (_e), (_f))
+
 /* term.c */
 sudo_dso_public bool sudo_term_cbreak_v1(int fd);
 #define sudo_term_cbreak(_a) sudo_term_cbreak_v1((_a))

lib/util/Makefile.in

@@ -150,7 +150,7 @@ LTOBJS = basename.lo @DIGEST@ event.lo fatal.lo key_val.lo gethostname.lo \
 	 multiarch.lo parseln.lo progname.lo rcstr.lo regex.lo roundup.lo \
 	 secure_path.lo setgroups.lo strsplit.lo strtobool.lo strtoid.lo \
 	 strtomode.lo strtonum.lo sudo_conf.lo sudo_debug.lo sudo_dso.lo \
-	 term.lo ttyname_dev.lo ttysize.lo uuid.lo \
+	 suspend_parent.lo term.lo ttyname_dev.lo ttysize.lo uuid.lo \
 	 @COMMON_OBJS@ @LTLIBOBJS@
 
 IOBJS = $(LTOBJS:.lo=.i)
@@ -1629,6 +1629,12 @@ sudo_dso.i: $(srcdir)/sudo_dso.c $(incdir)/compat/stdbool.h \
 	$(CC) -E -o $@ $(CPPFLAGS) $<
 sudo_dso.plog: sudo_dso.i
 	rm -f $@; pvs-studio --cfg $(PVS_CFG) --sourcetree-root $(top_srcdir) --skip-cl-exe yes --source-file $(srcdir)/sudo_dso.c --i-file $< --output-file $@
+suspend_parent.lo: $(srcdir)/suspend_parent.c $(top_builddir)/config.h
+	$(LIBTOOL) $(LTFLAGS) --mode=compile $(CC) -c -o $@ $(CPPFLAGS) $(CFLAGS) $(ASAN_CFLAGS) $(PIE_CFLAGS) $(HARDENING_CFLAGS) $(srcdir)/suspend_parent.c
+suspend_parent.i: $(srcdir)/suspend_parent.c $(top_builddir)/config.h
+	$(CC) -E -o $@ $(CPPFLAGS) $<
+suspend_parent.plog: suspend_parent.i
+	rm -f $@; pvs-studio --cfg $(PVS_CFG) --sourcetree-root $(top_srcdir) --skip-cl-exe yes --source-file $(srcdir)/suspend_parent.c --i-file $< --output-file $@
 term.lo: $(srcdir)/term.c $(incdir)/compat/stdbool.h $(incdir)/sudo_compat.h \
          $(incdir)/sudo_debug.h $(incdir)/sudo_queue.h $(incdir)/sudo_util.h \
          $(top_builddir)/config.h

lib/util/suspend_parent.c

@@ -1,7 +1,7 @@
 /*
  * SPDX-License-Identifier: ISC
  *
- * Copyright (c) 2009-2022 Todd C. Miller <Todd.Miller@sudo.ws>
+ * Copyright (c) 2009-2023 Todd C. Miller <Todd.Miller@sudo.ws>
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -30,17 +30,66 @@
 #include <fcntl.h>
 #include <signal.h>
 
-#include "sudo.h"
+#include "pathnames.h"
-#include "sudo_exec.h"
+#include "sudo_debug.h"
+#include "sudo_fatal.h"
+#include "sudo_gettext.h"
+#include "sudo_util.h"
 
+static volatile sig_atomic_t got_sigttou;
+
+/*
+ * SIGTTOU signal handler for term_restore that just sets a flag.
+ */
+static void
+sigttou(int signo)
+{
+    got_sigttou = 1;
+}
+
+/*
+ * Like tcsetpgrp() but restarts on EINTR _except_ for SIGTTOU.
+ * Returns 0 on success or -1 on failure, setting errno.
+ * Sets got_sigttou on failure if interrupted by SIGTTOU.
+ */
+static int
+tcsetpgrp_nobg(int fd, pid_t pgrp_id)
+{
+    struct sigaction sa, osa;
+    int rc;
+    debug_decl(tcsetpgrp_nobg, SUDO_DEBUG_UTIL);
+
+    /*
+     * If we receive SIGTTOU from tcsetpgrp() it means we are
+     * not in the foreground process group.
+     * This avoid a TOCTOU race compared to using tcgetpgrp().
+     */
+    memset(&sa, 0, sizeof(sa));
+    sigemptyset(&sa.sa_mask);
+    sa.sa_flags = 0; /* do not restart syscalls */
+    sa.sa_handler = sigttou;
+    got_sigttou = 0;
+    (void)sigaction(SIGTTOU, &sa, &osa);
+    do {
+	rc = tcsetpgrp(fd, pgrp_id);
+    } while (rc != 0 && errno == EINTR && !got_sigttou);
+    (void)sigaction(SIGTTOU, &osa, NULL);
+
+    debug_return_int(rc);
+}
+
+/*
+ * Suspend the main process in response to an interactive child process
+ * being suspended.
+ */
 void
-suspend_sudo_nopty(struct exec_closure *ec, int signo, pid_t my_pid,
+sudo_suspend_parent_v1(int signo, pid_t my_pid, pid_t my_pgrp, pid_t cmnd_pid,
-    pid_t my_pgrp, pid_t cmnd_pid)
+     void *closure, void (*callback)(void *, int))
 {
     struct sigaction sa, osa;
     pid_t saved_pgrp = -1;
     int fd;
-    debug_decl(suspend_sudo_nopty, SUDO_DEBUG_EXEC);
+    debug_decl(sudo_suspend_parent, SUDO_DEBUG_EXEC);
 
     /*
      * Save the controlling terminal's process group so we can restore
@@ -81,26 +130,28 @@ suspend_sudo_nopty(struct exec_closure *ec, int signo, pid_t my_pid,
 	}
     }
 
-    /* Log the suspend event. */
+    /* Run callback before we suspend. */
-    log_suspend(ec, signo);
+    if (callback != NULL)
+	callback(callback, signo);
 
     if (signo == SIGTSTP) {
 	memset(&sa, 0, sizeof(sa));
 	sigemptyset(&sa.sa_mask);
 	sa.sa_flags = SA_RESTART;
 	sa.sa_handler = SIG_DFL;
-	if (sudo_sigaction(SIGTSTP, &sa, &osa) != 0)
+	if (sigaction(SIGTSTP, &sa, &osa) != 0)
 	    sudo_warn(U_("unable to set handler for signal %d"), SIGTSTP);
     }
     if (kill(my_pid, signo) != 0)
 	sudo_warn("kill(%d, %d)", (int)my_pid, signo);
     if (signo == SIGTSTP) {
-	if (sudo_sigaction(SIGTSTP, &osa, NULL) != 0)
+	if (sigaction(SIGTSTP, &osa, NULL) != 0)
 	    sudo_warn(U_("unable to restore handler for signal %d"), SIGTSTP);
     }
 
-    /* Log the resume event. */
+    /* Run callback on resume. */
-    log_suspend(ec, SIGCONT);
+    if (callback != NULL)
+	callback(callback, SIGCONT);
 
     if (saved_pgrp != -1) {
 	/*

lib/util/util.exp.in

@@ -144,6 +144,7 @@ sudo_strtoid_v2
 sudo_strtoidx_v1
 sudo_strtomode_v1
 sudo_strtonum
+sudo_suspend_parent_v1
 sudo_term_cbreak_v1
 sudo_term_copy_v1
 sudo_term_eof

plugins/sudoers/visudo.c

@@ -93,7 +93,7 @@ static bool install_sudoers(struct sudoersfile *, bool, bool);
 static bool visudo_track_error(const char *file, int line, int column, const char *fmt, va_list args) sudo_printf0like(4, 0);
 static int print_unused(struct sudoers_parse_tree *, struct alias *, void *);
 static bool reparse_sudoers(char *, int, char **, bool, bool);
-static int run_command(const char *, char *const *);
+static int run_command(const char *, char *const *, bool);
 static void parse_sudoers_options(void);
 static void setup_signals(void);
 static void visudo_cleanup(void);
@@ -557,7 +557,7 @@ edit_sudoers(struct sudoersfile *sp, char *editor, int editor_argc,
 	goto done;
     }
 
-    if (run_command(editor, editor_argv) != -1) {
+    if (run_command(editor, editor_argv, true) != -1) {
 	if (sudo_gettime_real(&times[1]) == -1) {
 	    sudo_warn("%s", U_("unable to read the clock"));
 	    goto done;
@@ -820,7 +820,7 @@ install_sudoers(struct sudoersfile *sp, bool set_owner, bool set_mode)
 	    av[3] = NULL;
 
 	    /* And run it... */
-	    if (run_command(_PATH_MV, av) != 0) {
+	    if (run_command(_PATH_MV, av, false) != 0) {
 		sudo_warnx(U_("command failed: '%s %s %s', %s unchanged"),
 		    _PATH_MV, sp->tpath, sp->path, sp->path);
 		goto done;
@@ -895,9 +895,9 @@ setup_signals(void)
 }
 
 static int
-run_command(const char *path, char *const *argv)
+run_command(const char *path, char *const *argv, bool foreground)
 {
-    int status;
+    int fd, status;
     pid_t pid, rv;
     debug_decl(run_command, SUDOERS_DEBUG_UTIL);
 
@@ -906,6 +906,14 @@ run_command(const char *path, char *const *argv)
 	    sudo_fatal(U_("unable to execute %s"), path);
 	    break;	/* NOTREACHED */
 	case 0:
+	    /* Run command as the foreground process of a new process group. */
+	    if (foreground) {
+		pid = getpid();
+		setpgid(0, pid);
+		fd = open(_PATH_TTY, O_RDWR);
+		if (fd != -1)
+		    tcsetpgrp(fd, pid);
+	    }
 	    closefrom(STDERR_FILENO + 1);
 	    execv(path, argv);
 	    sudo_warn(U_("unable to run %s"), path);
@@ -914,11 +922,19 @@ run_command(const char *path, char *const *argv)
     }
 
     for (;;) {
-	rv = waitpid(pid, &status, 0);
+	rv = waitpid(pid, &status, WUNTRACED);
-	if (rv == -1 && errno != EINTR)
+	if (rv == -1) {
+	    if (errno == EINTR)
+		continue;
 	    break;
-	if (rv != -1 && !WIFSTOPPED(status))
+	}
+	if (!WIFSTOPPED(status))
 	    break;
+	if (foreground) {
+	    sudo_suspend_parent(WSTOPSIG(status), getpid(), getpgrp(),
+		pid, NULL, NULL);
+	    killpg(pid, SIGCONT);
+	}
     }
 
     if (rv != -1)

src/Makefile.in

@@ -145,8 +145,7 @@ OBJS = conversation.o copy_file.o edit_open.o env_hooks.o exec.o \
        exec_common.o exec_intercept.o exec_iolog.o exec_monitor.o \
        exec_nopty.o exec_preload.o exec_ptrace.o exec_pty.o get_pty.o \
        hooks.o limits.o load_plugins.o net_ifs.o parse_args.o preserve_fds.o \
-       signal.o sudo.o sudo_edit.o suspend_nopty.o tcsetpgrp_nobg.o \
+       signal.o sudo.o sudo_edit.o tgetpass.o ttyname.o utmp.o @SUDO_OBJS@
-       tgetpass.o ttyname.o utmp.o @SUDO_OBJS@
 
 IOBJS = $(OBJS:.o=.i) sesh.i sudo_intercept.i sudo_intercept_common.i
 
@@ -163,7 +162,7 @@ CHECK_NOEXEC_OBJS = check_noexec.o exec_common.o exec_preload.o
 
 CHECK_TTYNAME_OBJS = check_ttyname.o ttyname.o
 
-TEST_PTRACE_OBJS = suspend_nopty.o tcsetpgrp_nobg.o test_ptrace.o
+TEST_PTRACE_OBJS = test_ptrace.o
 
 LIBOBJDIR = $(top_builddir)/@ac_config_libobj_dir@/
 
@@ -1005,42 +1004,6 @@ sudo_intercept_common.i: $(srcdir)/sudo_intercept_common.c \
 	$(CC) -E -o $@ $(CPPFLAGS) $<
 sudo_intercept_common.plog: sudo_intercept_common.i
 	rm -f $@; pvs-studio --cfg $(PVS_CFG) --sourcetree-root $(top_srcdir) --skip-cl-exe yes --source-file $(srcdir)/sudo_intercept_common.c --i-file $< --output-file $@
-suspend_nopty.o: $(srcdir)/suspend_nopty.c $(incdir)/compat/stdbool.h \
-                 $(incdir)/sudo_compat.h $(incdir)/sudo_conf.h \
-                 $(incdir)/sudo_debug.h $(incdir)/sudo_event.h \
-                 $(incdir)/sudo_fatal.h $(incdir)/sudo_gettext.h \
-                 $(incdir)/sudo_plugin.h $(incdir)/sudo_queue.h \
-                 $(incdir)/sudo_util.h $(srcdir)/sudo.h $(srcdir)/sudo_exec.h \
-                 $(top_builddir)/config.h $(top_builddir)/pathnames.h
-	$(CC) -c $(CPPFLAGS) $(CFLAGS) $(ASAN_CFLAGS) $(PIE_CFLAGS) $(HARDENING_CFLAGS) $(srcdir)/suspend_nopty.c
-suspend_nopty.i: $(srcdir)/suspend_nopty.c $(incdir)/compat/stdbool.h \
-                 $(incdir)/sudo_compat.h $(incdir)/sudo_conf.h \
-                 $(incdir)/sudo_debug.h $(incdir)/sudo_event.h \
-                 $(incdir)/sudo_fatal.h $(incdir)/sudo_gettext.h \
-                 $(incdir)/sudo_plugin.h $(incdir)/sudo_queue.h \
-                 $(incdir)/sudo_util.h $(srcdir)/sudo.h $(srcdir)/sudo_exec.h \
-                 $(top_builddir)/config.h $(top_builddir)/pathnames.h
-	$(CC) -E -o $@ $(CPPFLAGS) $<
-suspend_nopty.plog: suspend_nopty.i
-	rm -f $@; pvs-studio --cfg $(PVS_CFG) --sourcetree-root $(top_srcdir) --skip-cl-exe yes --source-file $(srcdir)/suspend_nopty.c --i-file $< --output-file $@
-tcsetpgrp_nobg.o: $(srcdir)/tcsetpgrp_nobg.c $(incdir)/compat/stdbool.h \
-                  $(incdir)/sudo_compat.h $(incdir)/sudo_conf.h \
-                  $(incdir)/sudo_debug.h $(incdir)/sudo_event.h \
-                  $(incdir)/sudo_fatal.h $(incdir)/sudo_gettext.h \
-                  $(incdir)/sudo_plugin.h $(incdir)/sudo_queue.h \
-                  $(incdir)/sudo_util.h $(srcdir)/sudo.h \
-                  $(top_builddir)/config.h $(top_builddir)/pathnames.h
-	$(CC) -c $(CPPFLAGS) $(CFLAGS) $(ASAN_CFLAGS) $(PIE_CFLAGS) $(HARDENING_CFLAGS) $(srcdir)/tcsetpgrp_nobg.c
-tcsetpgrp_nobg.i: $(srcdir)/tcsetpgrp_nobg.c $(incdir)/compat/stdbool.h \
-                  $(incdir)/sudo_compat.h $(incdir)/sudo_conf.h \
-                  $(incdir)/sudo_debug.h $(incdir)/sudo_event.h \
-                  $(incdir)/sudo_fatal.h $(incdir)/sudo_gettext.h \
-                  $(incdir)/sudo_plugin.h $(incdir)/sudo_queue.h \
-                  $(incdir)/sudo_util.h $(srcdir)/sudo.h \
-                  $(top_builddir)/config.h $(top_builddir)/pathnames.h
-	$(CC) -E -o $@ $(CPPFLAGS) $<
-tcsetpgrp_nobg.plog: tcsetpgrp_nobg.i
-	rm -f $@; pvs-studio --cfg $(PVS_CFG) --sourcetree-root $(top_srcdir) --skip-cl-exe yes --source-file $(srcdir)/tcsetpgrp_nobg.c --i-file $< --output-file $@
 test_ptrace.o: $(srcdir)/regress/intercept/test_ptrace.c \
                $(incdir)/compat/endian.h $(incdir)/compat/stdbool.h \
                $(incdir)/sudo_compat.h $(incdir)/sudo_conf.h \

src/exec_iolog.c

@@ -533,8 +533,9 @@ log_stderr(const char *buf, unsigned int n, struct io_buffer *iob)
 
 /* Call I/O plugin suspend log method. */
 void
-log_suspend(struct exec_closure *ec, int signo)
+log_suspend(void *v, int signo)
 {
+    struct exec_closure *ec = v;
     struct plugin_container *plugin;
     const char *errstr = NULL;
     sigset_t omask;

src/exec_nopty.c

@@ -758,8 +758,8 @@ handle_sigchld_nopty(struct exec_closure *ec)
 
 	    /* If the main command is suspended, suspend sudo too. */
 	    if (pid == ec->cmnd_pid) {
-		suspend_sudo_nopty(ec, signo, ec->sudo_pid, ec->ppgrp,
+		sudo_suspend_parent(signo, ec->sudo_pid, ec->ppgrp,
-		    ec->cmnd_pid);
+		    ec->cmnd_pid, ec, log_suspend);
 	    }
 	} else {
 	    if (WIFSIGNALED(status)) {

src/regress/intercept/test_ptrace.c

@@ -104,13 +104,6 @@ sudo_sigaction(int signo, struct sigaction *sa, struct sigaction *osa)
     return sigaction(signo, sa, osa);
 }
 
-/* STUB */
-void
-log_suspend(struct exec_closure *ec, int signo)
-{
-    return;
-}
-
 int
 main(int argc, char *argv[])
 {
@@ -228,8 +221,8 @@ main(int argc, char *argv[])
 	    } else if (WIFSTOPPED(status)) {
 		if (exec_ptrace_stopped(pid, status, &closure)) {
 		    if (pid == child) {
-			suspend_sudo_nopty(NULL, WSTOPSIG(status), my_pid,
+			sudo_suspend_parent(WSTOPSIG(status), my_pid,
-			    my_pgrp, child);
+			    my_pgrp, child, NULL, NULL);
 			if (kill(child, SIGCONT) != 0)
 			    sudo_warn("kill(%d, SIGCONT)", (int)child);
 		    }

src/sudo.h

@@ -336,9 +336,6 @@ int add_preserved_fd(struct preserved_fd_list *pfds, int fd);
 void closefrom_except(int startfd, struct preserved_fd_list *pfds);
 void parse_preserved_fds(struct preserved_fd_list *pfds, const char *fdstr);
 
-/* setpgrp_nobg.c */
-int tcsetpgrp_nobg(int fd, pid_t pgrp_id);
-
 /* limits.c */
 void disable_coredump(void);
 void restore_limits(void);

src/sudo_exec.h

@@ -194,7 +194,7 @@ bool log_stdin(const char *buf, unsigned int n, struct io_buffer *iob);
 bool log_ttyout(const char *buf, unsigned int n, struct io_buffer *iob);
 bool log_stdout(const char *buf, unsigned int n, struct io_buffer *iob);
 bool log_stderr(const char *buf, unsigned int n, struct io_buffer *iob);
-void log_suspend(struct exec_closure *ec, int signo);
+void log_suspend(void *v, int signo);
 void log_winchange(struct exec_closure *ec, unsigned int rows, unsigned int cols);
 void io_buf_new(int rfd, int wfd, bool (*action)(const char *, unsigned int, struct io_buffer *), void (*read_cb)(int fd, int what, void *v), void (*write_cb)(int fd, int what, void *v), struct exec_closure *ec, struct io_buffer_list *head);
 int safe_close(int fd);
@@ -232,7 +232,4 @@ bool exec_ptrace_stopped(pid_t pid, int status, void *intercept);
 bool set_exec_filter(void);
 int exec_ptrace_seize(pid_t child);
 
-/* suspend_nopty.c */
-void suspend_sudo_nopty(struct exec_closure *ec, int signo, pid_t my_pid, pid_t my_pgrp, pid_t cmnd_pid);
-
 #endif /* SUDO_EXEC_H */

src/tcsetpgrp_nobg.c

@@ -1,71 +0,0 @@
-/*
- * SPDX-License-Identifier: ISC
- *
- * Copyright (c) 2017 Todd C. Miller <Todd.Miller@sudo.ws>
- *
- * Permission to use, copy, modify, and distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
- */
-
-/*
- * This is an open source non-commercial project. Dear PVS-Studio, please check it.
- * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
- */
-
-#include <config.h>
-#include <string.h>
-#include <unistd.h>
-#include <errno.h>
-#include <signal.h>
-
-#include "sudo.h"
-
-static volatile sig_atomic_t got_sigttou;
-
-/*
- * SIGTTOU signal handler for tcsetpgrp_nobg() that just sets a flag.
- */
-static void
-sigttou(int signo)
-{
-    got_sigttou = 1;
-}
-
-/*
- * Like tcsetpgrp() but restarts on EINTR _except_ for SIGTTOU.
- * Returns 0 on success or -1 on failure, setting errno.
- * Sets got_sigttou on failure if interrupted by SIGTTOU.
- */
-int
-tcsetpgrp_nobg(int fd, pid_t pgrp_id)
-{
-    struct sigaction sa, osa;
-    int rc;
-
-    /*
-     * If we receive SIGTTOU from tcsetpgrp() it means we are
-     * not in the foreground process group.
-     * This avoid a TOCTOU race compared to using tcgetpgrp().
-     */
-    memset(&sa, 0, sizeof(sa));
-    sigemptyset(&sa.sa_mask);
-    sa.sa_flags = 0; /* do not restart syscalls */
-    sa.sa_handler = sigttou;
-    got_sigttou = 0;
-    (void)sigaction(SIGTTOU, &sa, &osa);
-    do {
-	rc = tcsetpgrp(fd, pgrp_id);
-    } while (rc != 0 && errno == EINTR && !got_sigttou);
-    (void)sigaction(SIGTTOU, &osa, NULL);
-
-    return rc;
-}