Add in libutil, based on Cory Visi's variant of Michael Shmulevich's libutil

[uclinux-h8/uClibc.git] / libutil / openpty.c

diff --git a/libutil/openpty.c b/libutil/openpty.c
new file mode 100644 (file)
index 0000000..1c2adbf
--- /dev/null
+++ b/libutil/openpty.c
@@ -0,0 +1,142 @@
+/* Copyright (C) 1998, 1999 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Zack Weinberg <zack@rabi.phys.columbia.edu>, 1998.
+
+   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 <fcntl.h>
+#include <limits.h>
+#include <pty.h>
+#include <stdlib.h>
+#include <string.h>
+#include <termios.h>
+#include <unistd.h>
+#include <sys/types.h>
+
+extern int getpt (void);
+extern int grantpt (int fd);
+extern int ptsname_r (int fd, char *buf, size_t buflen);
+extern int unlockpt (int fd);
+
+/* Return the result of ptsname_r in the buffer pointed to by PTS,
+   which should be of length BUF_LEN.  If it is too long to fit in
+   this buffer, a sufficiently long buffer is allocated using malloc,
+   and returned in PTS.  0 is returned upon success, -1 otherwise.  */
+static int
+pts_name (int fd, char **pts, size_t buf_len)
+{
+  int rv;
+  char *buf = *pts;
+
+  for (;;)
+    {
+      char *new_buf;
+
+      if (buf_len)
+       {
+         rv = ptsname_r (fd, buf, buf_len);
+
+         if (rv != 0 || memchr (buf, '\0', buf_len))
+           /* We either got an error, or we succeeded and the
+              returned name fit in the buffer.  */
+           break;
+
+         /* Try again with a longer buffer.  */
+         buf_len += buf_len;   /* Double it */
+       }
+      else
+       /* No initial buffer; start out by mallocing one.  */
+       buf_len = 128;          /* First time guess.  */
+
+      if (buf != *pts)
+       /* We've already malloced another buffer at least once.  */
+       new_buf = realloc (buf, buf_len);
+      else
+       new_buf = malloc (buf_len);
+      if (! new_buf)
+       {
+         rv = -1;
+         errno = ENOMEM;
+         break;
+       }
+      buf = new_buf;
+    }
+
+  if (rv == 0)
+    *pts = buf;                /* Return buffer to the user.  */
+  else if (buf != *pts)
+    free (buf);                /* Free what we malloced when returning an error.  */
+
+  return rv;
+}
+
+/* Create pseudo tty master slave pair and set terminal attributes
+   according to TERMP and WINP.  Return handles for both ends in
+   AMASTER and ASLAVE, and return the name of the slave end in NAME.  */
+int
+openpty (int *amaster, int *aslave, char *name, struct termios *termp,
+        struct winsize *winp)
+{
+#ifdef PATH_MAX
+  char _buf[PATH_MAX];
+#else
+  char _buf[512];
+#endif
+  char *buf = _buf;
+  int master, slave;
+
+  master = getpt ();
+  if (master == -1)
+    return -1;
+
+  if (grantpt (master))
+    goto fail;
+
+  if (unlockpt (master))
+    goto fail;
+
+  if (pts_name (master, &buf, sizeof (_buf)))
+    goto fail;
+
+  slave = open (buf, O_RDWR | O_NOCTTY);
+  if (slave == -1)
+    {
+      if (buf != _buf)
+       free (buf);
+
+      goto fail;
+    }
+
+  /* XXX Should we ignore errors here?  */
+  if(termp)
+    tcsetattr (slave, TCSAFLUSH, termp);
+  if (winp)
+    ioctl (slave, TIOCSWINSZ, winp);
+
+  *amaster = master;
+  *aslave = slave;
+  if (name != NULL)
+    strcpy (name, buf);
+
+  if (buf != _buf)
+    free (buf);
+  return 0;
+
+ fail:
+  close (master);
+  return -1;
+}