Adding upstream version 5.2.37.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

lib/sh/zread.c

@@ -0,0 +1,228 @@
+/* zread - read data from file descriptor into buffer with retries */
+
+/* Copyright (C) 1999-2020 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/>.
+*/
+
+#include <config.h>
+
+#include <sys/types.h>
+
+#if defined (HAVE_UNISTD_H)
+#  include <unistd.h>
+#endif
+
+#include <signal.h>
+#include <errno.h>
+
+#if !defined (errno)
+extern int errno;
+#endif
+
+#ifndef SEEK_CUR
+#  define SEEK_CUR 1
+#endif
+
+#ifndef ZBUFSIZ
+#  define ZBUFSIZ 4096
+#endif
+
+extern int executing_builtin;
+
+extern void check_signals_and_traps (void);
+extern void check_signals (void);
+extern int signal_is_trapped (int);
+extern int read_builtin_timeout (int);
+
+/* Read LEN bytes from FD into BUF.  Retry the read on EINTR.  Any other
+   error causes the loop to break. */
+ssize_t
+zread (fd, buf, len)
+     int fd;
+     char *buf;
+     size_t len;
+{
+  ssize_t r;
+
+  check_signals ();	/* check for signals before a blocking read */
+  /* should generalize into a mechanism where different parts of the shell can
+     `register' timeouts and have them checked here. */
+  while (((r = read_builtin_timeout (fd)) < 0 || (r = read (fd, buf, len)) < 0) &&
+	     errno == EINTR)
+    {
+      int t;
+      t = errno;
+      /* XXX - bash-5.0 */
+      /* We check executing_builtin and run traps here for backwards compatibility */
+      if (executing_builtin)
+	check_signals_and_traps ();	/* XXX - should it be check_signals()? */
+      else
+	check_signals ();
+      errno = t;
+    }
+
+  return r;
+}
+
+/* Read LEN bytes from FD into BUF.  Retry the read on EINTR, up to three
+   interrupts.  Any other error causes the loop to break. */
+
+#ifdef NUM_INTR
+#  undef NUM_INTR
+#endif
+#define NUM_INTR 3
+
+ssize_t
+zreadretry (fd, buf, len)
+     int fd;
+     char *buf;
+     size_t len;
+{
+  ssize_t r;
+  int nintr;
+
+  for (nintr = 0; ; )
+    {
+      r = read (fd, buf, len);
+      if (r >= 0)
+	return r;
+      if (r == -1 && errno == EINTR)
+	{
+	  if (++nintr >= NUM_INTR)
+	    return -1;
+	  continue;
+	}
+      return r;
+    }
+}
+
+/* Call read(2) and allow it to be interrupted.  Just a stub for now. */
+ssize_t
+zreadintr (fd, buf, len)
+     int fd;
+     char *buf;
+     size_t len;
+{
+  check_signals ();
+  return (read (fd, buf, len));
+}
+
+/* Read one character from FD and return it in CP.  Return values are as
+   in read(2).  This does some local buffering to avoid many one-character
+   calls to read(2), like those the `read' builtin performs. */
+
+static char lbuf[ZBUFSIZ];
+static size_t lind, lused;
+
+ssize_t
+zreadc (fd, cp)
+     int fd;
+     char *cp;
+{
+  ssize_t nr;
+
+  if (lind == lused || lused == 0)
+    {
+      nr = zread (fd, lbuf, sizeof (lbuf));
+      lind = 0;
+      if (nr <= 0)
+	{
+	  lused = 0;
+	  return nr;
+	}
+      lused = nr;
+    }
+  if (cp)
+    *cp = lbuf[lind++];
+  return 1;
+}
+
+/* Don't mix calls to zreadc and zreadcintr in the same function, since they
+   use the same local buffer. */
+ssize_t
+zreadcintr (fd, cp)
+     int fd;
+     char *cp;
+{
+  ssize_t nr;
+
+  if (lind == lused || lused == 0)
+    {
+      nr = zreadintr (fd, lbuf, sizeof (lbuf));
+      lind = 0;
+      if (nr <= 0)
+	{
+	  lused = 0;
+	  return nr;
+	}
+      lused = nr;
+    }
+  if (cp)
+    *cp = lbuf[lind++];
+  return 1;
+}
+
+/* Like zreadc, but read a specified number of characters at a time.  Used
+   for `read -N'. */
+ssize_t
+zreadn (fd, cp, len)
+     int fd;
+     char *cp;
+     size_t len;
+{
+  ssize_t nr;
+
+  if (lind == lused || lused == 0)
+    {
+      if (len > sizeof (lbuf))
+	len = sizeof (lbuf);
+      nr = zread (fd, lbuf, len);
+      lind = 0;
+      if (nr <= 0)
+	{
+	  lused = 0;
+	  return nr;
+	}
+      lused = nr;
+    }
+  if (cp)
+    *cp = lbuf[lind++];
+  return 1;
+}
+
+void
+zreset ()
+{
+  lind = lused = 0;
+}
+
+/* Sync the seek pointer for FD so that the kernel's idea of the last char
+   read is the last char returned by zreadc. */
+void
+zsyncfd (fd)
+     int fd;
+{
+  off_t off, r;
+
+  off = lused - lind;
+  r = 0;
+  if (off > 0)
+    r = lseek (fd, -off, SEEK_CUR);
+
+  if (r != -1)
+    lused = lind = 0;
+}