Updated to fedora-glibc-20041018T0940

10 files changed, 690 insertions, 0 deletions

diff --git a/sysdeps/generic/memcpy_chk.c b/sysdeps/generic/memcpy_chk.c
new file mode 100644
index 0000000000..638cd0e4fb
--- /dev/null
+++ b/sysdeps/generic/memcpy_chk.c
@@ -0,0 +1,66 @@
+/* Copy memory to memory until the specified number of bytes
+   has been copied with error checking.  Overlap is NOT handled correctly.
+   Copyright (C) 1991, 1997, 2003, 2004 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Torbjorn Granlund (tege@sics.se).
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <string.h>
+#include <memcopy.h>
+#include <pagecopy.h>
+
+void *
+__memcpy_chk (dstpp, srcpp, len, dstlen)
+     void *dstpp;
+     const void *srcpp;
+     size_t len;
+     size_t dstlen;
+{
+  if (__builtin_expect (dstlen < len, 0))
+    __chk_fail ();
+
+  unsigned long int dstp = (long int) dstpp;
+  unsigned long int srcp = (long int) srcpp;
+
+  /* Copy from the beginning to the end.  */
+
+  /* If there not too few bytes to copy, use word copy.  */
+  if (len >= OP_T_THRES)
+    {
+      /* Copy just a few bytes to make DSTP aligned.  */
+      len -= (-dstp) % OPSIZ;
+      BYTE_COPY_FWD (dstp, srcp, (-dstp) % OPSIZ);
+
+      /* Copy whole pages from SRCP to DSTP by virtual address manipulation,
+	 as much as possible.  */
+
+      PAGE_COPY_FWD_MAYBE (dstp, srcp, len, len);
+
+      /* Copy from SRCP to DSTP taking advantage of the known alignment of
+	 DSTP.  Number of bytes remaining is put in the third argument,
+	 i.e. in LEN.  This number may vary from machine to machine.  */
+
+      WORD_COPY_FWD (dstp, srcp, len, len);
+
+      /* Fall out and copy the tail.  */
+    }
+
+  /* There are just a few bytes to copy.  Use byte memory operations.  */
+  BYTE_COPY_FWD (dstp, srcp, len);
+
+  return dstpp;
+}
diff --git a/sysdeps/generic/memmove_chk.c b/sysdeps/generic/memmove_chk.c
new file mode 100644
index 0000000000..f3b74d23d9
--- /dev/null
+++ b/sysdeps/generic/memmove_chk.c
@@ -0,0 +1,98 @@
+/* Copy memory to memory until the specified number of bytes
+   has been copied with error checking.  Overlap is handled correctly.
+   Copyright (C) 1991,1995,1996,1997,2003,2004 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Torbjorn Granlund (tege@sics.se).
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <string.h>
+#include <memcopy.h>
+#include <pagecopy.h>
+
+void *
+__memmove_chk (dest, src, len, destlen)
+     void *dest;
+     const void *src;
+     size_t len;
+     size_t destlen;
+{
+  if (__builtin_expect (destlen < len, 0))
+    __chk_fail ();
+
+  unsigned long int dstp = (long int) dest;
+  unsigned long int srcp = (long int) src;
+
+  /* This test makes the forward copying code be used whenever possible.
+     Reduces the working set.  */
+  if (dstp - srcp >= len)	/* *Unsigned* compare!  */
+    {
+      /* Copy from the beginning to the end.  */
+
+      /* If there not too few bytes to copy, use word copy.  */
+      if (len >= OP_T_THRES)
+	{
+	  /* Copy just a few bytes to make DSTP aligned.  */
+	  len -= (-dstp) % OPSIZ;
+	  BYTE_COPY_FWD (dstp, srcp, (-dstp) % OPSIZ);
+
+	  /* Copy whole pages from SRCP to DSTP by virtual address
+	     manipulation, as much as possible.  */
+
+	  PAGE_COPY_FWD_MAYBE (dstp, srcp, len, len);
+
+	  /* Copy from SRCP to DSTP taking advantage of the known
+	     alignment of DSTP.  Number of bytes remaining is put
+	     in the third argument, i.e. in LEN.  This number may
+	     vary from machine to machine.  */
+
+	  WORD_COPY_FWD (dstp, srcp, len, len);
+
+	  /* Fall out and copy the tail.  */
+	}
+
+      /* There are just a few bytes to copy.  Use byte memory operations.  */
+      BYTE_COPY_FWD (dstp, srcp, len);
+    }
+  else
+    {
+      /* Copy from the end to the beginning.  */
+      srcp += len;
+      dstp += len;
+
+      /* If there not too few bytes to copy, use word copy.  */
+      if (len >= OP_T_THRES)
+	{
+	  /* Copy just a few bytes to make DSTP aligned.  */
+	  len -= dstp % OPSIZ;
+	  BYTE_COPY_BWD (dstp, srcp, dstp % OPSIZ);
+
+	  /* Copy from SRCP to DSTP taking advantage of the known
+	     alignment of DSTP.  Number of bytes remaining is put
+	     in the third argument, i.e. in LEN.  This number may
+	     vary from machine to machine.  */
+
+	  WORD_COPY_BWD (dstp, srcp, len, len);
+
+	  /* Fall out and copy the tail.  */
+	}
+
+      /* There are just a few bytes to copy.  Use byte memory operations.  */
+      BYTE_COPY_BWD (dstp, srcp, len);
+    }
+
+  return dest;
+}
diff --git a/sysdeps/generic/mempcpy_chk.c b/sysdeps/generic/mempcpy_chk.c
new file mode 100644
index 0000000000..5297bbab92
--- /dev/null
+++ b/sysdeps/generic/mempcpy_chk.c
@@ -0,0 +1,67 @@
+/* Copy memory to memory until the specified number of bytes
+   has been copied, return pointer to following byte, with error checking.
+   Overlap is NOT handled correctly.
+   Copyright (C) 1991, 1997, 1998, 2002, 2004 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Torbjorn Granlund (tege@sics.se).
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <string.h>
+#include <memcopy.h>
+#include <pagecopy.h>
+
+void *
+__mempcpy_chk (dstpp, srcpp, len, dstlen)
+     void *dstpp;
+     const void *srcpp;
+     size_t len;
+     size_t dstlen;
+{
+  if (__builtin_expect (dstlen < len, 0))
+    __chk_fail ();
+
+  unsigned long int dstp = (long int) dstpp;
+  unsigned long int srcp = (long int) srcpp;
+
+  /* Copy from the beginning to the end.  */
+
+  /* If there not too few bytes to copy, use word copy.  */
+  if (len >= OP_T_THRES)
+    {
+      /* Copy just a few bytes to make DSTP aligned.  */
+      len -= (-dstp) % OPSIZ;
+      BYTE_COPY_FWD (dstp, srcp, (-dstp) % OPSIZ);
+
+      /* Copy whole pages from SRCP to DSTP by virtual address manipulation,
+	 as much as possible.  */
+
+      PAGE_COPY_FWD_MAYBE (dstp, srcp, len, len);
+
+      /* Copy from SRCP to DSTP taking advantage of the known alignment of
+	 DSTP.  Number of bytes remaining is put in the third argument,
+	 i.e. in LEN.  This number may vary from machine to machine.  */
+
+      WORD_COPY_FWD (dstp, srcp, len, len);
+
+      /* Fall out and copy the tail.  */
+    }
+
+  /* There are just a few bytes to copy.  Use byte memory operations.  */
+  BYTE_COPY_FWD (dstp, srcp, len);
+
+  return (void *) dstp;
+}
diff --git a/sysdeps/generic/memset_chk.c b/sysdeps/generic/memset_chk.c
new file mode 100644
index 0000000000..c311914395
--- /dev/null
+++ b/sysdeps/generic/memset_chk.c
@@ -0,0 +1,92 @@
+/* Copyright (C) 1991, 1997, 2003, 2004 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 Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <string.h>
+#include <memcopy.h>
+
+void *
+__memset_chk (dstpp, c, len, dstlen)
+     void *dstpp;
+     int c;
+     size_t len;
+     size_t dstlen;
+{
+  if (__builtin_expect (dstlen < len, 0))
+    __chk_fail ();
+
+  long int dstp = (long int) dstpp;
+
+  if (len >= 8)
+    {
+      size_t xlen;
+      op_t cccc;
+
+      cccc = (unsigned char) c;
+      cccc |= cccc << 8;
+      cccc |= cccc << 16;
+      if (OPSIZ > 4)
+	/* Do the shift in two steps to avoid warning if long has 32 bits.  */
+	cccc |= (cccc << 16) << 16;
+
+      /* There are at least some bytes to set.
+	 No need to test for LEN == 0 in this alignment loop.  */
+      while (dstp % OPSIZ != 0)
+	{
+	  ((byte *) dstp)[0] = c;
+	  dstp += 1;
+	  len -= 1;
+	}
+
+      /* Write 8 `op_t' per iteration until less than 8 `op_t' remain.  */
+      xlen = len / (OPSIZ * 8);
+      while (xlen > 0)
+	{
+	  ((op_t *) dstp)[0] = cccc;
+	  ((op_t *) dstp)[1] = cccc;
+	  ((op_t *) dstp)[2] = cccc;
+	  ((op_t *) dstp)[3] = cccc;
+	  ((op_t *) dstp)[4] = cccc;
+	  ((op_t *) dstp)[5] = cccc;
+	  ((op_t *) dstp)[6] = cccc;
+	  ((op_t *) dstp)[7] = cccc;
+	  dstp += 8 * OPSIZ;
+	  xlen -= 1;
+	}
+      len %= OPSIZ * 8;
+
+      /* Write 1 `op_t' per iteration until less than OPSIZ bytes remain.  */
+      xlen = len / OPSIZ;
+      while (xlen > 0)
+	{
+	  ((op_t *) dstp)[0] = cccc;
+	  dstp += OPSIZ;
+	  xlen -= 1;
+	}
+      len %= OPSIZ;
+    }
+
+  /* Write the last few bytes.  */
+  while (len > 0)
+    {
+      ((byte *) dstp)[0] = c;
+      dstp += 1;
+      len -= 1;
+    }
+
+  return dstpp;
+}
diff --git a/sysdeps/generic/readonly-area.c b/sysdeps/generic/readonly-area.c
new file mode 100644
index 0000000000..df5b96015c
--- /dev/null
+++ b/sysdeps/generic/readonly-area.c
@@ -0,0 +1,29 @@
+/* Copyright (C) 2004 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 Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+/* Return 1 if the whole area PTR .. PTR+SIZE is not writable.
+   Return -1 if it is writable.  */
+
+#include <stdlib.h>
+
+int
+__readonly_str (const void *ptr, size_t size)
+{
+  /* The conservative answer is that all strings are writable.  */
+  return -1;
+}
diff --git a/sysdeps/generic/stpcpy_chk.c b/sysdeps/generic/stpcpy_chk.c
new file mode 100644
index 0000000000..dacda0115a
--- /dev/null
+++ b/sysdeps/generic/stpcpy_chk.c
@@ -0,0 +1,45 @@
+/* Copyright (C) 1992, 1995, 1997, 2002, 2004 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 Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <string.h>
+
+
+/* Copy SRC to DEST, returning the address of the terminating '\0' in DEST.  */
+char *
+__stpcpy_chk (dest, src, destlen)
+     char *dest;
+     const char *src;
+     size_t destlen;
+{
+  register char *d = dest;
+  register const char *s = src;
+
+  do
+    {
+      if (__builtin_expect (destlen-- == 0, 0))
+	__chk_fail ();
+      *d++ = *s;
+    }
+  while (*s++ != '\0');
+
+  return d - 1;
+}
diff --git a/sysdeps/generic/strcat_chk.c b/sysdeps/generic/strcat_chk.c
new file mode 100644
index 0000000000..b3fb3470b7
--- /dev/null
+++ b/sysdeps/generic/strcat_chk.c
@@ -0,0 +1,58 @@
+/* Copyright (C) 1991, 1997, 2003, 2004 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 Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <string.h>
+#include <memcopy.h>
+
+
+/* Append SRC on the end of DEST.  */
+char *
+__strcat_chk (dest, src, destlen)
+     char *dest;
+     const char *src;
+     size_t destlen;
+{
+  char *s1 = dest;
+  const char *s2 = src;
+  reg_char c;
+
+  /* Find the end of the string.  */
+  do
+    {
+      if (__builtin_expect (destlen-- == 0, 0))
+	__chk_fail ();
+      c = *s1++;
+    }
+  while (c != '\0');
+
+  /* Make S1 point before the next character, so we can increment
+     it while memory is read (wins on pipelined cpus).  */
+  ++destlen;
+  s1 -= 2;
+
+  do
+    {
+      if (__builtin_expect (destlen-- == 0, 0))
+	__chk_fail ();
+      c = *s2++;
+      *++s1 = c;
+    }
+  while (c != '\0');
+
+  return dest;
+}
diff --git a/sysdeps/generic/strcpy_chk.c b/sysdeps/generic/strcpy_chk.c
new file mode 100644
index 0000000000..5c1ae44cd0
--- /dev/null
+++ b/sysdeps/generic/strcpy_chk.c
@@ -0,0 +1,46 @@
+/* Copyright (C) 1991, 1997, 2000, 2003, 2004 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 Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <stddef.h>
+#include <string.h>
+#include <memcopy.h>
+
+#undef strcpy
+
+/* Copy SRC to DEST with checking of destination buffer overflow.  */
+char *
+__strcpy_chk (dest, src, destlen)
+     char *dest;
+     const char *src;
+     size_t destlen;
+{
+  reg_char c;
+  char *s = (char *) src;
+  const ptrdiff_t off = dest - s - 1;
+
+  do
+    {
+      if (__builtin_expect (destlen-- == 0, 0))
+	__chk_fail ();
+      c = *s++;
+      s[off] = c;
+    }
+  while (c != '\0');
+
+  return dest;
+}
diff --git a/sysdeps/generic/strncat_chk.c b/sysdeps/generic/strncat_chk.c
new file mode 100644
index 0000000000..953b435a4b
--- /dev/null
+++ b/sysdeps/generic/strncat_chk.c
@@ -0,0 +1,100 @@
+/* Copyright (C) 1991, 1997, 2004 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 Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <string.h>
+
+#include <memcopy.h>
+
+
+char *
+__strncat_chk (s1, s2, n, s1len)
+     char *s1;
+     const char *s2;
+     size_t n;
+     size_t s1len;
+{
+  reg_char c;
+  char *s = s1;
+
+  /* Find the end of S1.  */
+  do
+    {
+      if (__builtin_expect (s1len-- == 0, 0))
+	__chk_fail ();
+      c = *s1++;
+    }
+  while (c != '\0');
+
+  /* Make S1 point before next character, so we can increment
+     it while memory is read (wins on pipelined cpus).  */
+  ++s1len;
+  s1 -= 2;
+
+  if (n >= 4)
+    {
+      size_t n4 = n >> 2;
+      do
+	{
+	  if (__builtin_expect (s1len-- == 0, 0))
+	    __chk_fail ();
+	  c = *s2++;
+	  *++s1 = c;
+	  if (c == '\0')
+	    return s;
+	  if (__builtin_expect (s1len-- == 0, 0))
+	    __chk_fail ();
+	  c = *s2++;
+	  *++s1 = c;
+	  if (c == '\0')
+	    return s;
+	  if (__builtin_expect (s1len-- == 0, 0))
+	    __chk_fail ();
+	  c = *s2++;
+	  *++s1 = c;
+	  if (c == '\0')
+	    return s;
+	  if (__builtin_expect (s1len-- == 0, 0))
+	    __chk_fail ();
+	  c = *s2++;
+	  *++s1 = c;
+	  if (c == '\0')
+	    return s;
+	} while (--n4 > 0);
+      n &= 3;
+    }
+
+  while (n > 0)
+    {
+      if (__builtin_expect (s1len-- == 0, 0))
+	__chk_fail ();
+      c = *s2++;
+      *++s1 = c;
+      if (c == '\0')
+	return s;
+      n--;
+    }
+
+  if (c != '\0')
+    {
+      if (__builtin_expect (s1len-- == 0, 0))
+	__chk_fail ();
+      *++s1 = '\0';
+    }
+
+  return s;
+}
diff --git a/sysdeps/generic/strncpy_chk.c b/sysdeps/generic/strncpy_chk.c
new file mode 100644
index 0000000000..bdede7738b
--- /dev/null
+++ b/sysdeps/generic/strncpy_chk.c
@@ -0,0 +1,89 @@
+/* Copyright (C) 1991, 1997, 2003, 2004 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 Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <string.h>
+#include <memcopy.h>
+
+
+char *
+__strncpy_chk (s1, s2, n, s1len)
+     char *s1;
+     const char *s2;
+     size_t n;
+     size_t s1len;
+{
+  reg_char c;
+  char *s = s1;
+
+  if (__builtin_expect (s1len < n, 0))
+    __chk_fail ();
+
+  --s1;
+
+  if (n >= 4)
+    {
+      size_t n4 = n >> 2;
+
+      for (;;)
+	{
+	  c = *s2++;
+	  *++s1 = c;
+	  if (c == '\0')
+	    break;
+	  c = *s2++;
+	  *++s1 = c;
+	  if (c == '\0')
+	    break;
+	  c = *s2++;
+	  *++s1 = c;
+	  if (c == '\0')
+	    break;
+	  c = *s2++;
+	  *++s1 = c;
+	  if (c == '\0')
+	    break;
+	  if (--n4 == 0)
+	    goto last_chars;
+	}
+      n = n - (s1 - s) - 1;
+      if (n == 0)
+	return s;
+      goto zero_fill;
+    }
+
+ last_chars:
+  n &= 3;
+  if (n == 0)
+    return s;
+
+  do
+    {
+      c = *s2++;
+      *++s1 = c;
+      if (--n == 0)
+	return s;
+    }
+  while (c != '\0');
+
+ zero_fill:
+  do
+    *++s1 = '\0';
+  while (--n > 0);
+
+  return s;
+}