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-rw-r--r--libc/termios/tcgetsid.c64
1 files changed, 64 insertions, 0 deletions
diff --git a/libc/termios/tcgetsid.c b/libc/termios/tcgetsid.c
new file mode 100644
index 000000000..35e1c95eb
--- /dev/null
+++ b/libc/termios/tcgetsid.c
@@ -0,0 +1,64 @@
+/* Copyright (C) 1997, 1999 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include <errno.h>
+#include <termios.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#define __USE_XOPEN_EXTENDED
+#include <unistd.h>
+
+
+/* Return the session ID of FD. */
+pid_t tcgetsid (int fd)
+{
+ pid_t pgrp;
+ pid_t sid;
+#ifdef TIOCGSID
+ static int tiocgsid_does_not_work;
+
+ if (! tiocgsid_does_not_work)
+ {
+ int serrno = errno;
+ int sid;
+
+ if (ioctl (fd, TIOCGSID, &sid) < 0)
+ {
+ if (errno == EINVAL)
+ {
+ tiocgsid_does_not_work = 1;
+ errno=serrno;
+ }
+ else
+ return (pid_t) -1;
+ }
+ else
+ return (pid_t) sid;
+ }
+#endif
+
+ pgrp = tcgetpgrp (fd);
+ if (pgrp == -1)
+ return (pid_t) -1;
+
+ sid = getsid (pgrp);
+ if (sid == -1 && errno == ESRCH)
+ errno=ENOTTY;
+
+ return sid;
+}