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Diffstat (limited to 'sysdeps/generic/memmove_chk.c')
| -rw-r--r-- | sysdeps/generic/memmove_chk.c | 98 |
1 files changed, 98 insertions, 0 deletions
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; +} |