1 files changed, 165 insertions, 0 deletions
diff --git a/lib/sh/input_avail.c b/lib/sh/input_avail.c
new file mode 100644
index 0000000..695165f
--- /dev/null
+++ b/lib/sh/input_avail.c
@@ -0,0 +1,165 @@
+/* input_avail.c -- check whether or not data is available for reading on a
+		    specified file descriptor. */
+
+/* Copyright (C) 2008,2009-2019 Free Software Foundation, Inc.
+
+   This file is part of GNU Bash, the Bourne Again SHell.
+
+   Bash is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   Bash 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with Bash.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#if defined (__TANDEM)
+#  include <floss.h>
+#endif
+
+#if defined (HAVE_CONFIG_H)
+#  include <config.h>
+#endif
+
+#include <sys/types.h>
+#include <fcntl.h>
+#if defined (HAVE_SYS_FILE_H)
+#  include <sys/file.h>
+#endif /* HAVE_SYS_FILE_H */
+
+#if defined (HAVE_PSELECT)
+#  include <signal.h>
+#endif
+
+#if defined (HAVE_UNISTD_H)
+#  include <unistd.h>
+#endif /* HAVE_UNISTD_H */
+
+#include "bashansi.h"
+
+#include "posixselect.h"
+
+#if defined (FIONREAD_IN_SYS_IOCTL)
+#  include <sys/ioctl.h>
+#endif
+
+#include <stdio.h>
+#include <errno.h>
+
+#if !defined (errno)
+extern int errno;
+#endif /* !errno */
+
+#if !defined (O_NDELAY) && defined (O_NONBLOCK)
+#  define O_NDELAY O_NONBLOCK	/* Posix style */
+#endif
+
+/* Return >= 1 if select/FIONREAD indicates data available for reading on
+   file descriptor FD; 0 if no data available.  Return -1 on error. */
+int
+input_avail (fd)
+     int fd;
+{
+  int result, chars_avail;
+#if defined(HAVE_SELECT)
+  fd_set readfds, exceptfds;
+  struct timeval timeout;
+#endif
+
+  if (fd < 0)
+    return -1;
+
+  chars_avail = 0;
+
+#if defined (HAVE_SELECT)
+  FD_ZERO (&readfds);
+  FD_ZERO (&exceptfds);
+  FD_SET (fd, &readfds);
+  FD_SET (fd, &exceptfds);
+  timeout.tv_sec = 0;
+  timeout.tv_usec = 0;
+  result = select (fd + 1, &readfds, (fd_set *)NULL, &exceptfds, &timeout);
+  return ((result <= 0) ? 0 : 1);
+#endif
+
+#if defined (FIONREAD)
+  errno = 0;
+  result = ioctl (fd, FIONREAD, &chars_avail);
+  if (result == -1 && errno == EIO)
+    return -1;
+  return (chars_avail);
+#endif
+
+  return 0;
+}
+
+/* Wait until NCHARS are available for reading on file descriptor FD.
+   This can wait indefinitely. Return -1 on error. */
+int
+nchars_avail (fd, nchars)
+     int fd;
+     int nchars;
+{
+  int result, chars_avail;
+#if defined(HAVE_SELECT)
+  fd_set readfds, exceptfds;
+#endif
+#if defined (HAVE_PSELECT)
+  sigset_t set, oset;
+#endif
+
+  if (fd < 0 || nchars < 0)
+    return -1;
+  if (nchars == 0)
+    return (input_avail (fd));
+
+  chars_avail = 0;
+
+#if defined (HAVE_SELECT)
+  FD_ZERO (&readfds);
+  FD_ZERO (&exceptfds);
+  FD_SET (fd, &readfds);
+  FD_SET (fd, &exceptfds);
+#endif
+#if defined (HAVE_SELECT) || defined (HAVE_PSELECT)
+  sigprocmask (SIG_BLOCK, (sigset_t *)NULL, &set);
+#  ifdef SIGCHLD
+  sigaddset (&set, SIGCHLD);
+#  endif
+  sigemptyset (&oset);
+#endif
+
+  while (1)
+    {
+      result = 0;
+#if defined (HAVE_PSELECT)
+      /* XXX - use pselect(2) to block SIGCHLD atomically */
+      result = pselect (fd + 1, &readfds, (fd_set *)NULL, &exceptfds, (struct timespec *)NULL, &set);
+#elif defined (HAVE_SELECT)
+      sigprocmask (SIG_BLOCK, &set, &oset);
+      result = select (fd + 1, &readfds, (fd_set *)NULL, &exceptfds, (struct timeval *)NULL);
+      sigprocmask (SIG_BLOCK, &oset, (sigset_t *)NULL);
+#endif
+      if (result < 0)
+        return -1;
+
+#if defined (FIONREAD)
+      errno = 0;
+      result = ioctl (fd, FIONREAD, &chars_avail);
+      if (result == -1 && errno == EIO)
+        return -1;
+      if (chars_avail >= nchars)
+        break;
+#else
+      break;
+#endif
+    }
+
+  return 0;
+}